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1
WILLIAMS, N. W., J. M. T. PENROSE, and D. R. HOSE. "Computer Model Analysis of the Swanson and Sutter Metacarpophalangeal Joint Implants." Journal of Hand Surgery 25, no. 2 (April 2000): 212–20. http://dx.doi.org/10.1054/jhsb.1999.0352.
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A representative model which mimics the behaviour of Silastic® finger metacarpophalangeal joint implants was constructed using a finite element software package. The modelled implants were moved through a range of flexion, lateral deviation and a combination of both. Pistoning of both implants stems occurred within the modelled medullary cavities. For equivalent flexion angles, the Sutter implant produced a higher stress field than the Swanson implant, and the field was positioned at the central hinge mechanism. In both implants, lateral deviation increased the internal stress concentrations more than when pure flexion was applied. Overall the Swanson style of implant had lower stress magnitudes than the Sutter implant, and it is predicted that the Sutter implant will be more likely to fail than the Swanson. The failure mode for the Sutter implant would be at the central hinge region. The Swanson implant is likely to fail at the central hinge-stem interface regions.
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Tonetto, Mateus Rodrigues, Matheus Coelho Bandéca, Vinicius Ibiapina Mascarenhas, Lívia Jacovassi Tavares, and Lara Maria Ferreira Mendes. "The use of Computer Guided Implant Surgery in Oral Rehabilitation: A Literature Review." World Journal of Dentistry 5, no. 1 (2014): 60–63. http://dx.doi.org/10.5005/jp-journals-10015-1259.
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ABSTRACT The virtual planning of dental implants is a technology that brings many benefits to practitioners and patients who undergo a prosthetic rehabilitation. The cone beam computed tomography (CBCT) produces high-resolution images allowing to implant a breakthrough in preoperative planning, making planning more accurate. The virtually guided surgery is a surgery planned based computers in a 3D anatomical model of the patient and transferred to the surgical procedure through guides built especially for this purpose. The objective of this study is to report the current concepts in the literature on virtually guided surgery, emphasizing its applicability, indications and benefits in prosthetic rehabilitation with dental implants. Thus, it was concluded that the technique of guided surgery represents an advance in the field of implantology significantly decreasing errors, bringing good results postoperative and increasing predictability of the results, one technique suitable for various cases. How to cite this article Mascarenhas VI, de Molon RS, Tavares LJ, Mendes LMF, Tonetto MR, Bandeca MC. The use of Computer Guided Implant Surgery in Oral Rehabilitation: A Literature Review. World J Dent 2014;5(1):60-63.
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Edelmann, Cornelia, Martin Wetzel, Anne Knipper, Ralph G. Luthardt, and Sigmar Schnutenhaus. "Accuracy of Computer-Assisted Dynamic Navigation in Implant Placement with a Fully Digital Approach: A Prospective Clinical Trial." Journal of Clinical Medicine 10, no. 9 (April 21, 2021): 1808. http://dx.doi.org/10.3390/jcm10091808.
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Background: This prospective clinical study aimed to investigate a possible deviation between the digitally planned implant position and the position achieved using dynamic navigation. The aim of the study was to establish clinical effectiveness and precision of implantation using dynamic navigation. Methods: Twenty consecutive patients received an implant (iSy-Implantat, Camlog, Wimsheim, Germany). One screw implant was placed in one jaw with remaining dentition of at least six teeth. The workflow was fully digital. Digital implant planning was conducted using cone-beam computed tomography (CBCT) and an intraoral scan of the actual condition. Twenty implants were subsequently placed using a dynamic computer-assisted procedure. The clinical situation of the implant position was recorded using an intraoral scan. Using these data, models were produced via 3D printing, and CBCTs of these models were made using laboratory analogs. Deviations of the achieved implant position from the planned position were determined using evaluation software. Results: The evaluation of 20 implants resulted in a mean angle deviation of 2.7° (95% CI 2.2–3.3°). The 3D deviation at the implant shoulder was 1.83 mm (95% CI 1.34–2.33 mm). No significant differences were found for any of the parameters between the implantation in the upper or lower jaw and an open or flapless procedure (p-value < 0.05). Conclusion: The clinical trial showed that sufficiently precise implantation was possible with the dynamic navigation system used here. Dynamic navigation can improve the quality of implant positioning. In particular, the procedure allows safe positioning of the implants in minimally invasive procedures, which usually cannot be performed freehand in this form. A clinical benefit and effectiveness can be determined from the results.
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Lee, Jungwon, Young-Jun Lim, Bongju Kim, and Ki-Tae Koo. "Early Loading of Mandibular Molar Single Implants: 1 Year Results of a Randomized Controlled Clinical Trial." Materials 13, no. 18 (September 4, 2020): 3912. http://dx.doi.org/10.3390/ma13183912.
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The purpose of this study was to compare the implant survival, peri-implant marginal bone level, and peri-implant soft tissue of three different types of implants. This was performed with an early loading protocol, using a complete digital workflow, for one year of follow-up. Twenty-four patients with a single missing tooth in the mandibular posterior region were randomly assigned to the control group (SLActive Bone level implant; Institut Straumann AG, Basel, Switzerland), experiment group 1 (CMI IS-III Active implant; Neobiotech Co., Seoul, Korea), and experiment group 2 (CMI IS-III HActive implant; Neobiotech Co., Seoul, Korea). For each patient, a single implant was installed using the surgical template, and all prostheses were fabricated using a computer-aided design/computer-aided manufacturing system on a 3-dimensional model. A provisional prosthesis was implanted at 4 weeks, and a definitive monolithic zirconia prosthesis was substituted 12 weeks following the implant placement. The implant stability quotient (ISQ) and peri-implant soft tissue parameters were measured, and periapical radiographs were taken at 1, 3, 4, 8, 12, 24, 36, and 48 weeks after implant placements. Seven implants in the control group, nine implants in the experiment 1 group, and eight implants in the experiment 2 group were analyzed. There were no significant differences among the three groups in terms of insertion torque, ISQ values between surgery and 8 weeks of follow-up, marginal bone loss at 48 weeks of follow-up, and peri-implant soft tissue parameters (P > 0.05). Statistically significant differences in ISQ values were observed between the control and experiment 1 groups, and the control and experiment 2 groups at the 12 to 48 weeks’ follow-ups. Within the limits of this prospective study, an early loading protocol can be applied as a predictable treatment modality in posterior mandibular single missing restorations, achieving proper primary stability.
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Schnutenhaus, Sigmar, Anne Knipper, Martin Wetzel, Cornelia Edelmann, and Ralph Luthardt. "Accuracy of Computer-Assisted Dynamic Navigation as a Function of Different Intraoral Reference Systems: An In Vitro Study." International Journal of Environmental Research and Public Health 18, no. 6 (March 21, 2021): 3244. http://dx.doi.org/10.3390/ijerph18063244.
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The aim of this in vitro study was to determine whether the process chain influences the accuracy of a computer-assisted dynamic navigation procedure. Four different data integration workflows using cone-beam computed tomography (CBCT), conventional impressions, and intraoral digitization with and without reference markers were analyzed. Digital implant planning was conducted using data from the CBCT scans and 3D data of the oral models. The restoration of the free end of the lower jaw was simulated. Fifteen models were each implanted with two new teeth for each process chain. The models were then scanned with scan bodies screwed onto the implants. The deviations between the planned and achieved implant positions were determined. The evaluation of all 120 implants resulted in a mean angular deviation of 2.88 ± 2.03°. The mean 3D deviation at the implant shoulder was 1.53 ± 0.70 mm. No significant differences were found between the implant regions. In contrast, the workflow showed significant differences in various parameters. The position of the reference marker affected the accuracy of the implant position. The in vitro examination showed that precise implantation is possible with the dynamic navigation system used in this study. The results are of the same order of magnitude that can be achieved using static navigation methods. Clinical studies are yet to confirm the results of this study.
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Liu, Yun-Ting, and Han-Yi Cheng. "Development of Effects on Chewing with Mandibular Fixed Dental Bridges with Implants via Finite Element Method." Journal of Biomaterials and Tissue Engineering 10, no. 8 (August 1, 2020): 1071–76. http://dx.doi.org/10.1166/jbt.2020.2380.
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The aim of the present research was to evaluate the biomechanics of dental bridge with and without implant. Oral models were reconstructed by 3D computer tomography images to simulate oral environment. The stress is an important role in dental bridge applications for osseointegration. Many studies have investigated finite element researches for dental implants; however, few have evaluated a model for dental bridge with and without implant. The results revealed that abnormal focusing stress was found when dental bridge was used with implant. Moreover, the unbalance situation was found on the model with only one implant, the highest stress appeared in the present group. Dental bridge with implants would be an effective means of recovering dental performance. However, the present study showed that if only one pier with dental implant in bridge treatment has a potential to increase abnormal stress, and uniformly distributing stress.
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Baek, Yeon-Wha, Young-Jun Lim, Jungwon Lee, Ki-Tae Koo, Myung-Joo Kim, and Ho-Beom Kwon. "One-Year Results of a Randomized Controlled Clinical Trial of Immediately Loaded Short Implants Placed in the Lower Posterior Single Molar Using a Complete Digital Workflow." Applied Sciences 9, no. 7 (March 27, 2019): 1282. http://dx.doi.org/10.3390/app9071282.
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The purpose of this randomized clinical trial is to evaluate immediately loaded single implants with varying lengths in the posterior mandible using a fully digital, model-free prosthetic-driven implant planning pathway, and to compare clinical and radiological outcomes of short and long implants. The 52 patients with the single tooth missing in the posterior molar regions of the mandible were randomly assigned to the control (CMI IS-III active® long implant; 5.0 × 10 mm) and experimental (CMI IS-III active® short implant; 5.5 × 6.6, 7.3, 8.5 mm) groups. For each patient, a single implant was placed using the computer aided surgical template and all prostheses were fabricated by means of computer-aided design/computer-aided manufacturing (CAD/CAM) system on the virtual model. The patients received provisional and definitive monolithic zirconia prostheses at 1 week and 12 weeks after implant surgery, respectively. The implant stability quotient (ISQ) measurements and periapical radiographs were taken and peri-implant parameters were evaluated at 1, 3, 4, 8, 12, 24, 36, and 48 weeks after surgery. Nineteen long implants and 27 short implants were finally used for the statistical analysis. There was no significant difference between the groups in terms of insertion torque, ISQ values (except 3 weeks), marginal bone loss, and peri-implant soft tissue parameters (p > 0.05). Both groups exhibited no stability dip during the early phase of healing. The average marginal bone loss from the baseline of implant placement for the control and experimental groups was −0.07 and 0.03 mm after 12 weeks and 0.06 and 0.05 mm after 48 weeks. All of the soft tissue parameters were within normal limits. Within the limits of the short term follow up, immediate loading of short single implants can be considered as one of predictable treatment modality in mandible with reduced bone height when primary stability can be achieved.
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Huang, Wan-Ting, and Han-Yi Cheng. "Finite Element Analysis of Stress in Dental Bridge with Implant." Journal of Biomaterials and Tissue Engineering 10, no. 6 (June 1, 2020): 743–48. http://dx.doi.org/10.1166/jbt.2020.2338.
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The objective of this research was to investigate dental bridges with and without implants. Threedimensional (3D) mandible models were reconstructed by computer tomography (CT) to simulate biting behaviors. The dental implant is an important factor in dental bridge applications. Several studies have investigated finite element models for dental implants; however, few have examined a model for dental bridge with implant. The results revealed that stress was significantly increased when dental bridge was used with implant. Moreover, the dental bridge with implant group demonstrated a relatively big stress in mandible, which was 4.01% lower compared with that of the control group. Dental bridge would be an effective means of recovering dental performance. However, the present research stated that the implant of dental bridge has a potential to increase abnormal stress, and uniformly distributing stress in the dental bridges.
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Emery, Robert W., Scott A. Merritt, Kathryn Lank, and Jason D. Gibbs. "Accuracy of Dynamic Navigation for Dental Implant Placement–Model-Based Evaluation." Journal of Oral Implantology 42, no. 5 (October 1, 2016): 399–405. http://dx.doi.org/10.1563/aaid-joi-d-16-00025.
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The purpose of this model-based study was to determine the accuracy of placing dental implants using a new dynamic navigation system. This investigation focuses on measurements of overall accuracy for implant placement relative to the virtual plan in both dentate and edentulous models, and provides a comparison with a meta-analysis of values reported in the literature for comparable static guidance, dynamic guidance, and freehand placement studies. This study involves 1 surgeon experienced with dynamic navigation placing implants in models under clinical simulation using a dynamic navigation system (X-Guide, X-Nav Technologies, LLC, Lansdale, Pa) based on optical triangulation tracking. Virtual implants were placed into planned sites using the navigation system computer. Post–implant placement cone-beam scans were taken. These scans were mesh overlaid with the virtual plan and used to determine deviations from the virtual plan. The primary outcome variables were platform and angular deviations comparing the actual placement to the virtual plan. The angular accuracy of implants delivered using the tested device was 0.89° ± 0.35° for dentate case types and 1.26° ± 0.66° for edentulous case types, measured relative to the preoperative implant plan. Three-dimensional positional accuracy was 0.38 ± 0.21 mm for dentate and 0.56 ± 0.17 mm for edentulous, measured from the implant apex.
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Yi, Hee-Gyeong, Yeong-Jin Choi, Jin Woo Jung, Jinah Jang, Tae-Ha Song, Suhun Chae, Minjun Ahn, Tae Hyun Choi, Jong-Won Rhie, and Dong-Woo Cho. "Three-dimensional printing of a patient-specific engineered nasal cartilage for augmentative rhinoplasty." Journal of Tissue Engineering 10 (January 2019): 204173141882479. http://dx.doi.org/10.1177/2041731418824797.
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Autologous cartilages or synthetic nasal implants have been utilized in augmentative rhinoplasty to reconstruct the nasal shape for therapeutic and cosmetic purposes. Autologous cartilage is considered to be an ideal graft, but has drawbacks, such as limited cartilage source, requirements of additional surgery for obtaining autologous cartilage, and donor site morbidity. In contrast, synthetic nasal implants are abundantly available but have low biocompatibility than the autologous cartilages. Moreover, the currently used nasal cartilage grafts involve additional reshaping processes, by meticulous manual carving during surgery to fit the diverse nose shape of each patient. The final shapes of the manually tailored implants are highly dependent on the surgeons’ proficiency and often result in patient dissatisfaction and even undesired separation of the implant. This study describes a new process of rhinoplasty, which integrates three-dimensional printing and tissue engineering approaches. We established a serial procedure based on computer-aided design to generate a three-dimensional model of customized nasal implant, and the model was fabricated through three-dimensional printing. An engineered nasal cartilage implant was generated by injecting cartilage-derived hydrogel containing human adipose-derived stem cells into the implant containing the octahedral interior architecture. We observed remarkable expression levels of chondrogenic markers from the human adipose-derived stem cells grown in the engineered nasal cartilage with the cartilage-derived hydrogel. In addition, the engineered nasal cartilage, which was implanted into mouse subcutaneous region, exhibited maintenance of the exquisite shape and structure, and striking formation of the cartilaginous tissues for 12 weeks. We expect that the developed process, which combines computer-aided design, three-dimensional printing, and tissue-derived hydrogel, would be beneficial in generating implants of other types of tissue.
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Bugbee, William D., Hideki Mizu-uchi, Shantanu Patil, and Darryl D'Lima. "Accuracy of Implant Placement Utilizing Customized Patient Instrumentation in Total Knee Arthroplasty." Advances in Orthopedics 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/891210.
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Customized patient instrumentation (CPI) combines preoperative planning with customized cutting jigs to position and align implants during total knee arthroplasty (TKA). We compared postoperative implant alignment of patients undergoing surgery with CPI to traditional TKA instrumentation for accuracy of implant placement. Twenty-five consecutive TKAs using CPI were analyzed. Preoperative CT scans of the lower extremities were segmented using a computer program. Limb alignment and mechanical axis were computed. Virtual implantation of computer-aided design models was done. Postoperative coronal and sagittal view radiographs were obtained. Using 3D image-matching software, relative positions of femoral and tibial implants were determined. Twenty-five TKAs implanted using traditional instrumentation were also analyzed. For CPI, difference in alignment from the preoperative plan was calculated. In the CPI group, the mean absolute difference between the planned and actual femoral placements was 0.67° in the coronal plane and 1.2° in the sagittal plane. For tibial alignment, the mean absolute difference was 0.9° in the coronal plane and 1.3° in the sagittal plane. For traditional instrumentation, difference from ideal placement for the femur was 1.5° in the coronal plane and 2.3° in the sagittal plane. For the tibia, the difference was 1.8° in the coronal plane. CPI achieved accurate implant positioning and was superior to traditional TKA instrumentation.
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Franchina, Alessio, Luigi V. Stefanelli, Fabio Maltese, George A. Mandelaris, Alessandro Vantaggiato, Michele Pagliarulo, Nicola Pranno, Edoardo Brauner, Francesca De Angelis, and Stefano Di Carlo. "Validation of an Intra-Oral Scan Method Versus Cone Beam Computed Tomography Superimposition to Assess the Accuracy between Planned and Achieved Dental Implants: A Randomized In Vitro Study." International Journal of Environmental Research and Public Health 17, no. 24 (December 14, 2020): 9358. http://dx.doi.org/10.3390/ijerph17249358.
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Computer aided implantology is the safest way to perform dental implants. The research of high accuracy represents a daily effort. The validated method to assess the accuracy of placed dental implants is the superimposition of a pre-operative and a post-operative cone beam computed tomography (CBCT) with planned and placed implants. This procedure is accountable for a biologic cost for the patient. To investigate alternative procedure for accuracy assessment, fifteen resin casts were printed. For each model, six implants were digitally planned and then placed following three different approaches: (a) template guided free hand, (b) static computer aided implantology (SCAI), and (c) dynamic computer aided implantology (DCAI). The placement accuracy of each implant was performed via two methods: the CBCT comparison described above and a matching between implant positions recovered from the original surgical plan with those obtained with a post-operative intraoral scan (IOS). Statistically significant mean differences between guided groups (SCAI and DCAI) and the free hand group were found at all considered deviations, while no differences resulted between the SCAI and DCAI approaches. Moreover, no mean statistically significant differences were found between CBCT and IOS assessment, confirming the validity of this new method.
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Evans, Zachary P., Walter G. Renne, Thierry R. Bacro, Anthony S. Mennito, Mark E. Ludlow, and Michael K. Lecholop. "Anatomic Customization of Root-Analog Dental Implants With Cone-Beam CT and CAD/CAM Fabrication: A Cadaver-Based Pilot Evaluation." Journal of Oral Implantology 44, no. 1 (February 1, 2018): 15–26. http://dx.doi.org/10.1563/aaid-joi-d-17-00090.
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Existing root-analog dental implant systems have no standardized protocols regarding retentive design, surface manipulation, or prosthetic attachment design relative to the site's unique anatomy. Historically, existing systems made those design choices arbitrarily. For this report, strategies were developed that deliberately reference the adjacent anatomy, implant and restorable path of draw, and bone density for implant and retentive design. For proof of concept, dentate arches from human cadavers were scanned using cone-beam computed tomography and then digitally modeled. Teeth of interest were virtually extracted and manipulated via computer-aided design to generate root-analog implants from zirconium. We created a stepwise protocol for analyzing and developing the implant sites, implant design and retention, and prosthetic emergence and connection all from the pre-op cone-beam data. Root-analog implants were placed at the time of extraction and examined radiographically and mechanically concerning ideal fit and stability. This study provides proof of concept that retentive root-analog implants can be produced from cone-beam data while improving fit, retention, safety, esthetics, and restorability when compared to the existing protocols. These advancements may provide the critical steps necessary for clinical relevance and success of immediately placed root-analog implants. Additional studies are necessary to validate the model prior to clinical trial.
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Ajami, Elnaz, Cong Fu, Hai Bo Wen, Jeffrey Bassett, Sun Jin Park, and Marie Pollard. "Early Bone Healing on Hydroxyapatite-Coated and Chemically-Modified Hydrophilic Implant Surfaces in an Ovine Model." International Journal of Molecular Sciences 22, no. 17 (August 28, 2021): 9361. http://dx.doi.org/10.3390/ijms22179361.
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Implant topography affects early peri-implant bone healing by changing the osteoconduction rate in the surrounding biological environment. Implant surfaces have been designed to promote faster and stronger bone formation for rapid and stable prosthesis loading. Early peri-implant bone healing has been observed with a sandblasted, acid-etched implant that was chemically modified to be hydrophilic (cmSLA). The present study investigates whether early peri-implant bone healing extends to a rough surface implant with a high crystalline hydroxyapatite surface (TSV MP-1 HA). Three implants were randomly placed in porous trabecular bone within both medial femoral condyles of 10 sheep. Early peri-implant bone stability was measured at 3- and 6-weeks healing time following implant insertion. Results indicated a similar implant stability quotient between the implants at insertion and over time. The significant increase over time of reverse torque values with respect to insertion torque (p < 0.001) did not differ between the implants. However, the bone-to-implant contact of TSV MP-1 HA was significantly higher than that of cmSLA implants at 6 weeks (p < 0.01). These data validate previous findings of a hydrophilic implant surface and extend the observation of early osseointegration to a rough surface implant in porous trabecular bone.
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Thangwarawut, Pisut, Pokpong Amornvit, Dinesh Rokaya, and Sirichai Kiattavorncharoen. "Comparison of Different Types of Static Computer-Guided Implant Surgery in Varying Bone Inclinations." Materials 15, no. 9 (April 20, 2022): 3004. http://dx.doi.org/10.3390/ma15093004.
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This research aimed to compare the accuracy of dental implant placement among three types of surgical guide: metal sleeve with key handle (Nobel guide, Nobel Biocare, Göteborg, Sweden), metal sleeve without key handle, and non-sleeve without key handle (Dentium full guide kit, Dentium Co., Seoul, Korea) when placing the implant in different bone inclinations. A total of 72 polyurethane bone models were fabricated in different inclinations (0°, 45°, and 60°). The dental implants were placed in bone models following the company’s recommendations. After dental implants were installed, the digital scans were done by an extraoral scanner. The deviations of the dental implant position were evaluated by superimposition between post-implant placement and reference model by using GOM inspect software. The deviation measurement was shown in 5 parameters: angular deviation, 3D deviation at the crest, 3D deviation at the apex, lateral linear deviation, and vertical linear deviation. The data were analyzed using One-way ANOVA and post-hoc tests at a significance level of 0.05. The accuracy of the dental implant position was not significantly influenced by the difference in the surgical guide system (p > 0.05). There were significant differences between placed and planned implant positions in the different inclinations of the bone. A significant difference was found in all parameters of 0° and 60° bone inclinations (p < 0.05). At 0° and 45°, angulated bone showed significant differences except in 3D deviation at the apex. Between 45° and 60° were significant differences only in angular deviation. Within the limitations of this study, the accuracy of implant placement among three types of surgical guides (Non-sleeve without key handle, Metal sleeve without key handle, and Metal sleeve with key handle) from two companies (Dentium and Nobel Biocare) was similar. Hence, the operators can choose the surgical guide system according to their preference. The inclination of bone can influence the angulation of dental implants.
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Chrcanovic, Bruno R., Davidson R. Oliveira, and Antônio L. Custódio. "Accuracy Evaluation of Computed Tomography–Derived Stereolithographic Surgical Guides in Zygomatic Implant Placement in Human Cadavers." Journal of Oral Implantology 36, no. 5 (October 1, 2010): 345–55. http://dx.doi.org/10.1563/aaid-joi-d-09-00074.
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Abstract Presurgical planning is essential to achieve esthetic and functional implants. For implant planning and placement, the association of computer-aided design (CAD) and computer-aided manufacturing (CAM) techniques furnishes some advantages regarding tridimensional determination of the patient's anatomy and fabrication of both anatomic models and surgical guides. The goal of this clinical study was to determine the angular deviations between planned and placed zygomatic implants using stereolithographic surgical guides in human cadavers. A total of 16 zygomatic implants were placed, 4 in each cadaver, with the use of stereolithographic (SLA) surgical guides generated by computed tomography (CT). A new CT scan was made after implant insertion. The angle between the long axis of the planned and actual implants was calculated. The mean angular deviation of the long axis between the planned and placed implants was 8.06 ± 6.40 (mean ± SD) for the anterior-posterior view, and 11.20 ± 9.75 (mean ± SD) for the caudal-cranial view. Use of the zygomatic implant, in the context of this protocol, should probably be reevaluated because some large deviations were noted. An implant insertion guiding system is needed because this last step is carried out manually. It is recommended that the sinus slot technique should be used together with the CT-based drilling guide to enhance final results. Further research to enhance the precision of zygomatic implant placement should be undertaken.
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Likibi, Fidele, Michel Assad, Christine Coillard, Gilles Chabot, and Charles-H. Rivard. "PERIPROSTHETIC BONE DENSITY CHANGES EVALUATION USING COMPUTED TOMOGRAPHY." Hirurgiâ pozvonočnika, no. 4 (December 15, 2005): 072–76. http://dx.doi.org/10.14531/ss2005.4.72-76.
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The aim of this study was to examine the effect of the presence of two types of metallic intervertebral lumbar fusion implants (a porous nitinol and a hollow titanium cylindrical implants) in the implant peripheral tissue after 3, 6 and 12 months post-implantation in a lumbar sheep model in order to evaluate and compare the biofunctionality and biocompatibility of both implants. 19 sheep were used to evaluate this bone density variation using computer tomography (CT). 16 of them received both implants at either level L2–L3 or L4–L5 and 3 other non-treated animals were used as controls. Results indicated that PNT obtained a superior biofunctionality that the conventional titanium implant. However, the biocompatibility of porous nitinol seemed comparable to that of titanium – a well-known long-term implant material.
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Mešić, Elmedin, Enis Muratović, Lejla Redžepagić-Vražalica, Nedim Pervan, Adis J. Muminović, Muamer Delić, and Mirza Glušac. "Experimental & FEM Analysis of Orthodontic Mini-Implant Design on Primary Stability." Applied Sciences 11, no. 12 (June 12, 2021): 5461. http://dx.doi.org/10.3390/app11125461.
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The main objective of this research is to establish a connection between orthodontic mini-implant design, pull-out force and primary stability by comparing two commercial mini-implants or temporary anchorage devices, Tomas®-pin and Perfect Anchor. Mini-implant geometric analysis and quantification of bone characteristics are performed, whereupon experimental in vitro pull-out test is conducted. With the use of the CATIA (Computer Aided Three-dimensional Interactive Application) CAD (Computer Aided Design)/CAM (Computer Aided Manufacturing)/CAE (Computer Aided Engineering) system, 3D (Three-dimensional) geometric models of mini-implants and bone segments are created. Afterwards, those same models are imported into Abaqus software, where finite element models are generated with a special focus on material properties, boundary conditions and interactions. FEM (Finite Element Method) analysis is used to simulate the pull-out test. Then, the results of the structural analysis are compared with the experimental results. The FEM analysis results contain information about maximum stresses on implant–bone system caused due to the pull-out force. It is determined that the core diameter of a screw thread and conicity are the main factors of the mini-implant design that have a direct impact on primary stability. Additionally, stresses generated on the Tomas®-pin model are lower than stresses on Perfect Anchor, even though Tomas®-pin endures greater pull-out forces, the implant system with implemented Tomas®-pin still represents a more stressed system due to the uniform distribution of stresses with bigger values.
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Kim, Seong-Min, Keunbada Son, Duk-Yeon Kim, and Kyu-Bok Lee. "Digital Evaluation of the Accuracy of Computer-Guided Dental Implant Placement: An In Vitro Study." Applied Sciences 9, no. 16 (August 16, 2019): 3373. http://dx.doi.org/10.3390/app9163373.
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Compared to traditional implant surgical guides, computer-assisted implant surgical guides can be considered for positioning implants in the final prosthesis. These computer-assisted implant surgical guides can be easily fabricated with personal 3D printers after being designed with implant planning CAD software. Although the accuracy of computer-assisted implant surgical guides fabricated using personal 3D printers is an important factor in their clinical use, there is still a lack of research examining their accuracy. Therefore, this study evaluated the accuracy of computer-assisted implant surgical guides, which were designed using two implant planning CAD software programs (Deltanine and R2gate software) and fabricated with personal 3D printers using a non-radiographic method. Amongst the patients who visited Kyungpook National University Dental Hospital, one patient scheduled to undergo surgery of the left mandibular second premolar was randomly selected. Twenty partially edentulous resin study models were produced using a 3D printer. Using the Deltanine and R2gate implant planning CAD software, 10 implant surgical guides per software were designed and produced using a personal 3D printer. The implants (SIII SA (Ø 4.0, L = 10 mm), Osstem, Busan, Korea) were placed by one skilled investigator using the computer-assisted implant surgical guides. To confirm the position of the actual implant fixture, the study models with the implant fixtures were scanned with a connected scan body to extract the STL files, and then overlapped with the scanned file by connecting the scan body-implant fixture complex. As a result, the mean apical deviation of the Deltanine and R2gate software was 0.603 ± 0.19 mm and 0.609 ± 0.18 mm, while the mean angular deviation was 1.97 ± 0.84° and 1.92 ± 0.52°, respectively. There was no significant difference between the two software programs (p > 0.05). Thus, the accuracy of the personal 3D printing implant surgical guides is in the average range allowed by the dental clinician.
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Szejka, Anderson Luis, Osíris Canciglieri, Marcelo Rudek, and Hervé Panetto. "A Conceptual Knowledge-Link Model for Supporting Dental Implant Process." Advanced Materials Research 945-949 (June 2014): 3424–29. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.3424.
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Computer aided techniques widely used as diagnostic and surgical procedures tools are scarcely applied in implantology, which continues using visualization of CT images to define the parameters for dental implant process leaving to the dentist discretion the implant determination, since only the images analysis is non-deterministic. Thus, this research proposes the development of a knowledge-link model integrated to a reasoner system to support dental implant process through information modeling. The system presents an interface that interacts with the user and consists of reasoning mechanisms connected by knowledge-links to a base of knowledge that enables information translation, conversion and sharing. The results obtained using the model showed that it is a valuable tool in the decisions making made by the surgeon in the dental implant planning process as it will be based on concrete and measurable data generated by the system through the analysis of the patient’s tomographic images and implants data.
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A, Manmadhachary, Santosh Kumar Malyala, Ravi Kumar Y., Haranadha Reddy M., and Adityamohan Alwala. "Design & Manufacturing of Implant for reconstructive surgery: A Case Study." KnE Engineering 2, no. 2 (February 9, 2017): 143. http://dx.doi.org/10.18502/keg.v2i2.608.
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<p>Additive Manufacturing (AM), also known as 3D printing is an emerging technology in oral & maxillofacial surgery with respect to reconstructive bone surgery. Such treatment protocols often require customized implants to fulfill the functional and aesthetic requirements. Currently, such customized implants are being manufactured using AM technology. This paper describes a mandible defect of oral & maxillofacial surgery. The fracture and defect of the mandible inferior border is one of the serious complications during alignment and fixing of the implant. Reconstruction of such defects is daunting tasks. The case report describes a method based on Computer Aided Design (CAD) and AM for individual design, fabrication and implantation of a mandible inferior border. A 40-year old male meet an accident with rash drive. The patient specific customized implant is designed with patient Computed Tomography (CT) data. The CT images in Digital Imaging and Communication in Medicine (DICOM) file format is used to develop a 3D CAD model of customized implant. The implant is designed to maintain the symmetry of mandible from right to left. The designed implant model is manufactured by Fused Deposition Modelling (FDM) techniques with a biocompatible material. The patient mandible prototype model was manufactured by AM process, which is helpful for pre-planning of surgical procedures. For these pre-planning surgical procedures, a perfect fit obtained during surgery. The patient ultimately regained reasonable mandible contour and appearance of the face. </p>
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Matsuoka, Takashi, Tamaki Nakano, Satoshi Yamaguchi, Shinji Ono, Shota Watanabe, Takumi Sato, and Hirofumi Yatani. "Effects of Implant–Abutment Connection Type and Inter-Implant Distance on Inter-Implant Bone Stress and Microgap: Three-Dimensional Finite Element Analysis." Materials 14, no. 9 (May 6, 2021): 2421. http://dx.doi.org/10.3390/ma14092421.
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The attainment of a good aesthetic outcome in dental implant treatment requires inter-implant papilla reconstruction, which is very difficult to perform. Maintenance of the inter-implant bone is essential for maintenance of the inter-implant papilla. The aim of this study was to investigate the mechanical influences of the implant–abutment connection type and inter-implant distance on the inter-implant bone by using three-dimensional finite element analysis. Three computer-aided design models of two-piece implants were designed: external connection (EC), internal connection (IC), and conical connection (CC). In each model, two identical implants were placed with inter-implant distances of 3.0, 2.5, and 2.0 mm. The maximum principal stress and microgap were evaluated. The stress values of the inter-implant bone decreased in the following order: IC, EC, and CC. The microgap decreased in the following order: EC, IC, and CC. Regardless of the type of implant–abutment connection, the stress of the inter-implant bone increased as the inter-implant distance decreased. The microgap barely changed as the inter-implant distance decreased. A CC implant is a mechanically advantageous implant–abutment connection type for maintenance of the inter-implant bone. With an inter-implant distance of less than 3.0 mm, use of a CC implant might suppress absorption of the inter-implant bone.
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KAMAL, ZEINAB, and GHOLAMREZA ROUHI. "A PARAMETRIC INVESTIGATION OF THE EFFECTS OF CERVICAL DISC PROSTHESES WITH UPWARD AND DOWNWARD NUCLEI ON SPINE BIOMECHANICS." Journal of Mechanics in Medicine and Biology 16, no. 07 (November 2016): 1650092. http://dx.doi.org/10.1142/s0219519416500925.
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This work aimed at investigating the influence of Baguera and Discocerv cervical disc prostheses, with mobile downward center of rotation (COR) and fixed upward COR, respectively, on the biomechanical behavior of C4–C6 cervical spine. For this purpose, using computed tomography (CT) data, a parametric nonlinear finite element (FE) model of intact C4–C6 spinal segments was developed, and an artificial disc was implanted at C5–C6 level. To assess the influence of implants on the biomechanics of cervical spine, the FE models were analyzed in flexion, extension, lateral bending, and axial rotation, and the results were presented in the range of motion (ROM) curves, and torsional stiffness. Results of this study, in agreement with the literature, suggested that both Baguera and Discocerv implants might be able to preserve the motion, and limit the alteration of the biomechanics of adjacent levels. Except for the possible confliction of adjacent vertebrae at the implanted level with Baguera implant in lateral bending, results of this study also indicated that the movability and downward COR of Baguera disc prosthesis caused ROMs of the implanted segment to be more similar to the intact model than Discocerv implant. Moreover, the upward COR of Discocerv implant may result in over-distraction on facets in the maximal flexion, with the ratio of 1.22 versus 1.36, and consequently facet syndrome during extension for Bageura and Discocerv disc prostheses, respectively.
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Li, Xinyu, Changjiang Wang, Yuan Guo, and Weiyi Chen. "An Approach to Developing Customized Total Knee Replacement Implants." Journal of Healthcare Engineering 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/9298061.
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Total knee replacement (TKR) has been performed for patients with end-stage knee joint arthritis to relieve pain and gain functions. Most knee replacement patients can gain satisfactory knee functions; however, the range of motion of the implanted knee is variable. There are many designs of TKR implants; it has been suggested by some researchers that customized implants could offer a better option for patients. Currently, the 3-dimensional knee model of a patient can be created from magnetic resonance imaging (MRI) or computed tomography (CT) data using image processing techniques. The knee models can be used for patient-specific implant design, biomechanical analysis, and creating bone cutting guide blocks. Researchers have developed patient-specific musculoskeletal lower limb model with total knee replacement, and the models can be used to predict muscle forces, joint forces on knee condyles, and wear of tibial polyethylene insert. These available techniques make it feasible to create customized implants for individual patients. Methods and a workflow of creating a customized total knee replacement implant for improving TKR kinematics and functions are discussed and presented in this paper.
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Dashevskiy, I. N., D. A. Gribov, and V. N. Olesova. "PERSONIFIED BIOMECHANICS OF EDENTULOUS JAW WITH RESTORATION ON THE SCHEME OF “ALL-ON-4” AND WITH PARALLEL IMPLANTS." Russian Journal of Dentistry 23, no. 1 (February 15, 2019): 21–23. http://dx.doi.org/10.18821/1728-2802-2019-23-1-21-23.
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The technology of patient-specific computer planning of the restoration process of the edentulous mandible dentition using dental implants is considered. A model of the jaw and distribution of elastic modules by its volume are reconstructed from a computer tomogram. The model is supplemented with virtual implants and a model of the prosthetic structure and is passed on to the finite element complex, where the loading and supporting conditions are specified. Biomechanical analysis and comparison of two implant placement schemes (“All-on-4” and in parallel implants) is carried out for two types of loading that model biting and chewing.
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Sultan, Haseeb, Muhammad Owais, Jiho Choi, Tahir Mahmood, Adnan Haider, Nadeem Ullah, and Kang Ryoung Park. "Artificial Intelligence-Based Solution in Personalized Computer-Aided Arthroscopy of Shoulder Prostheses." Journal of Personalized Medicine 12, no. 1 (January 14, 2022): 109. http://dx.doi.org/10.3390/jpm12010109.
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Background: Early recognition of prostheses before reoperation can reduce perioperative morbidity and mortality. Because of the intricacy of the shoulder biomechanics, accurate classification of implant models before surgery is fundamental for planning the correct medical procedure and setting apparatus for personalized medicine. Expert surgeons usually use X-ray images of prostheses to set the patient-specific apparatus. However, this subjective method is time-consuming and prone to errors. Method: As an alternative, artificial intelligence has played a vital role in orthopedic surgery and clinical decision-making for accurate prosthesis placement. In this study, three different deep learning-based frameworks are proposed to identify different types of shoulder implants in X-ray scans. We mainly propose an efficient ensemble network called the Inception Mobile Fully-Connected Convolutional Network (IMFC-Net), which is comprised of our two designed convolutional neural networks and a classifier. To evaluate the performance of the IMFC-Net and state-of-the-art models, experiments were performed with a public data set of 597 de-identified patients (597 shoulder implants). Moreover, to demonstrate the generalizability of IMFC-Net, experiments were performed with two augmentation techniques and without augmentation, in which our model ranked first, with a considerable difference from the comparison models. A gradient-weighted class activation map technique was also used to find distinct implant characteristics needed for IMFC-Net classification decisions. Results: The results confirmed that the proposed IMFC-Net model yielded an average accuracy of 89.09%, a precision rate of 89.54%, a recall rate of 86.57%, and an F1.score of 87.94%, which were higher than those of the comparison models. Conclusion: The proposed model is efficient and can minimize the revision complexities of implants.
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Chang, Shih-Hao, Hsiang-I. Mei, and Chun-Li Lin. "Integrating CAD and 3D-Printing Techniques to Construct an In Vitro Laser Standard Treatment Platform for Evaluating the Effectiveness of Sterilization by Er:YAG Laser in Peri-Implant Intra-Bony Defects." Applied Sciences 10, no. 10 (May 15, 2020): 3431. http://dx.doi.org/10.3390/app10103431.
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This study established an in vitro model mimicking clinical peri-implant intra-bony defects. We investigated the effect of access limitation and the bactericidal effectiveness of erbium-doped yttrium, aluminum and garnet (Er:YAG) laser irradiation in shallow and deep peri-implant defects at different tooth positions. Reverse engineering, computer-aided design (CAD), and 3D-printing techniques were integrated to establish physical peri-implant intra-bony defect models at mandibular central incisor, first premolar, and first molar positions with shallow (2 mm depth) or deep (6 mm depth) defects and with 1.5 mm and 1.8 mm widths at the bottom and crestal portions of the alveolar process, respectively. Three-dimensional printed suites at the corresponding implant sites replaced experimental implant specimens for the investigation of bacterial adhesion in individuals. Dental implants with diameters of 3, 4 and 5 mm were utilized at the mandibular incisor, premolar, and molar positions, respectively. Bacterial adhesion of Gram (–) Escherichia coli on the exposed implant surfaces prior to sterilization was assessed. Sterilization with shallow and deep intra-bony defects was investigated by measuring the reduction of residual viable bacteria on implants after 60 s of irradiation with an Er:YAG laser. The adhesion rate of Gram (–) Escherichia coli on the investigated implant surfaces ranged from 1% to 3% (1.76 ± 1.25%, 2.19 ± 0.75% and 2.66 ± 1.26% for 3, 4, and 5 mm implants, respectively). With shallow peri-implant bony defects, the Er:YAG laser sterilization rates were 99.6 ± 0.5%, 99.3 ± 0.41% and 93.8 ± 7.65% at mandibular incisor, premolar, and molar positions, respectively. Similarly, sterilization rates in deep peri-implant defects were 99 ± 1.35%, 99.1 ± 0.98% and 97.14 ± 2.57%, respectively. A 3D-printed model with replaceable implant specimens mimicking human peri-implant intra-bony defects was established and tested in vitro. This investigation demonstrated effective sterilization using Er:YAG laser irradiation in both shallow and deep peri-implant intra-bony defects at different positions and diameters of dental implants.
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Nagasao, Tomohisa, Junpei Miyamoto, Hongmei Jin, Tamotsu Tamaki, Yasushige Isshiki, Tsuyoshi Kaneko, and Tatsuo Nakajima. "The Dynamics in Implantation for Patients with Clefts." Cleft Palate-Craniofacial Journal 43, no. 1 (January 2006): 84–91. http://dx.doi.org/10.1597/04-091r1.1.
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Objective To investigate the stresses and strains of an endosseous dental implant in patients with different types of cleft palate in a finite element model. Materials and Methods Seven three-dimensional (3D) maxillary models were designed on a personal computer according to computed tomography slice data obtained from seven dry skulls. Next, computer-aided modification was performed on each model to produce three other 3D models with different cleft patterns. Thus, four model types with different cleft patterns were designed and termed NORM (without cleft), ALVEOLAR (only alveolar cleft), PALATAL (only palatal cleft), and COMPLETE (complete cleft). An implant was embedded into the molar region of each model, and a 300-N vertical load and 50-N horizontal load were applied to simulate mastication. Under these conditions, the stresses occurring at the implant-bone interface were calculated by finite element analysis. Results Different stress patterns were observed between the models with a palatal cleft (PALATAL and COMPLETE) and those without palatal cleft (NORM and ALVEOLAR). Regarding vertical load application, greater stresses occurred in PALATAL and COMPLETE types than in NORM and ALVEOLAR types. On application of a horizontal load, though the stresses did not show quantitative difference, their vector patterns differed. Conclusion In patients with palatal clefts, characteristic stress patterns occur on the bone-implant interface during mastication. This should be taken into consideration when performing an implant treatment in patients with clefts.
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Lin, Junxiong, Ge Zhang, Zhenyu Jiang, Liqun Tang, and Keqian Lian. "Evaluation of Biomechanical Health Degree of Peri-Implant Bone Through Finite Element Analysis: A First Approach." International Journal of Applied Mechanics 10, no. 09 (November 2018): 1850097. http://dx.doi.org/10.1142/s1758825118500977.
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The biomechanical health degree of peri-implant bone plays a critical role during the service of implants. This paper presents a preliminary exploration of the quantitative evaluation of the biomechanical health degree for the bone tissues around dental implant through finite element method. The finite element model of a part of mandible with three molars is constructed based on computer tomography scan image as a control sample, which is supposed to represent a healthy state. The model of treated mandible is made by replacing the middle tooth in the healthy model with a commercial implant. A regional average strain energy density (RASED) is proposed as a more accurate index to describe the stress state of peri-implant bone tissues, compared with the widely used maximum equivalent von Mises stress. The simulation shows that the stress state in peri-implant bone, i.e., the distribution and level of stress, is highly dependent on the modulus of implant material. Among the implants made of materials with various moduli, including Ti, stainless steel, zirconia, porous Ti, dentin material and polyether-ether-ketone (PEEK), the ones with medium modulus (15–40[Formula: see text]GPa) are found to achieve relatively healthy stress states. This study provides an effective tool to assess the risk of overloading or stress shielding in peri-implant bone tissues. It demonstrates a great potential in the optimization of design, production and usage of implants.
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Cenkoglu, Brunilda, Nilufer Balcioglu, Tayfun Ozdemir, and Eitan Mijiritsky. "The Effect of the Length and Distribution of Implants for Fixed Prosthetic Reconstructions in the Atrophic Posterior Maxilla: A Finite Element Analysis." Materials 12, no. 16 (August 11, 2019): 2556. http://dx.doi.org/10.3390/ma12162556.
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In this study, different prosthetic designs that could be applied instead of advanced surgical techniques in atrophic maxilla were evaluated with finite element analysis. Atrophic posterior maxilla was modeled using computer tomography images and four models were prepared as follows: Model 1 (M1), two implants supporting a three-unit distal cantilever prosthesis; Model 2 (M2), two implants supporting a three-unit conventional fixed partial denture; Model 3 (M3), three implants supporting three connected crowns; and Model 4 (M4), two implants supporting two connected crowns. Implants 4 mm in width and 8 mm or 13 mm in length were used. A linear three-dimensional finite element programme was used for analysis. The maximum principle stress (tensile) and minimum principle stress (compressive) were used to display stress in cortical and cancellous bones. The von Mises criteria were used to evaluate the stress on the implants. M1 was found to be the most risky model. The short dental arch case (M4) revealed the lowest stresses among the models but is not recommended when one more implant can be placed because of the bending forces that could occur at the mesial implant. In M2 and M3, the distal implants were placed bicortically between the crestal and sinus cortical plates, causing a fall of the stresses because of the bicortical stability of these implants.
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Zubrzycki, Jarosław, and Natalia Smidova. "Computer-Aided Design of Human Knee Implant." Applied Mechanics and Materials 613 (August 2014): 172–81. http://dx.doi.org/10.4028/www.scientific.net/amm.613.172.
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This paper presents the design process of human knee implant. The design has been used CT scans from the actual clinical trials. To make a 3D model from CT images Materialise Mimics software was used. On the basis of the resulting model, further work was carried out to obtain a STL model is necessary to carry out research numerical finite element method. This paper presents the results of numerical only one element of which is the medical polyethylene insert, which will act as a prosthetic meniscus.
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Tsai, Fu-Hui, and Han-Yi Cheng. "Evaluation of Structural and Biomechanical Characterization of Implant for Cranial Restoration." Journal of Biomaterials and Tissue Engineering 9, no. 7 (July 1, 2019): 898–903. http://dx.doi.org/10.1166/jbt.2019.2075.
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The objective this research was to investigate the biomechanical properties of various structures and thicknesses of implants for cranial restoration. A three-dimensional (3D) printing (3DP) technique has been applied in factories for several decades, but it was only recently introduced to the dental field less than 10 years ago. The structures of pre-shaped cranial mesh implants are critical factors for clinical applications. Many previous studies used finite element models to investigate for implants, but few examined a 3D model for pre-shaped cranial mesh implants with different structures and thicknesses. 3D cranial models were reconstructed using computer tomography to simulate preshaped cranial mesh implants under physical impacts. Data indicated that the stress significantly decreased when implants with greater thicknesses were used. Moreover, the implant with a circular structure created a relatively smaller stress that was approximately 7% lower compared to the implant with a triangular structure. As described above, the results of the present study demonstrate that 3DP-Ti is a reliable material of implants for cranial restoration.
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Velasco-Ortega, Eugenio, Ivan Ortiz-García, Alvaro Jiménez-Guerra, Loreto Monsalve-Guil, Fernando Muñoz-Guzón, Roman A. Perez, and F. Javier Gil. "Comparison between Sandblasted Acid-Etched and Oxidized Titanium Dental Implants: In Vivo Study." International Journal of Molecular Sciences 20, no. 13 (July 3, 2019): 3267. http://dx.doi.org/10.3390/ijms20133267.
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The surface modifications of titanium dental implants play important roles in the enhancement of osseointegration. The objective of the present study was to test two different implant surface treatments on a rabbit model to investigate the osseointegration. The tested surfaces were: a) acid-etched surface with sandblasting treatment (SA) and b) an oxidized implant surface (OS). The roughness was measured by an interferometeric microscope with white light and the residual stress of the surfaces was measured with X-ray residual stress Bragg–Bentano diffraction. Six New Zealand white rabbits were used for the in vivo study. Implants with the two different surfaces (SA and OS) were inserted in the femoral bone. After 12 weeks of implantation, histological and histomorphometric analyses of the blocks containing the implants and the surrounding bone were performed. All the implants were correctly implanted and no signs of infection were observed. SA and OS surfaces were both surrounded by newly formed trabeculae. Histomorphometric analysis revealed that the bone–implant contact % (BIC) was higher around the SA implants (53.49 ± 8.46) than around the OS implants (50.94 ± 16.42), although there were no significant statistical differences among them. Both implant surfaces (SA and OS) demonstrated a good bone response with significant amounts of newly formed bone along the implant surface after 12 weeks of implantation. These results confirmed the importance of the topography and physico–chemical properties of dental implants in the osseointegration.
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Han, Yen-Ting, Wei-Chun Lin, Fang-Yu Fan, Chih-Long Chen, Chia-Cheng Lin, and Hsin-Chung Cheng. "Comparison of Dental Surface Image Registration and Fiducial Marker Registration: An In Vivo Accuracy Study of Static Computer-Assisted Implant Surgery." Journal of Clinical Medicine 10, no. 18 (September 16, 2021): 4183. http://dx.doi.org/10.3390/jcm10184183.
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This study compared the accuracy of static computer-assisted implant surgery (sCAIS) planned through dental surface image registration and fiducial marker registration. Stone models of 30 patients were converted into digital dental casts by using a desktop scanner. Cone-beam computed tomography (CBCT) was performed and superimposed to the digital dental casts with two methods: matching the dental surface images or matching the fiducial markers on a stereolithographic radiographic template. Following the implant planning, stereolithographic surgical guides were fabricated, and 56 fully guided implants were inserted by the same doctor. Deviations between planned and inserted implants were measured and compared using postoperative CBCT images. After adjustment for other potential influencing factors, compared with the fiducial marker registration group, significantly larger mean lateral deviations were noted in the dental surface registration group at both the implant platform and apex (p = 0.0188 and 0.0371, respectively). However, the mean lateral deviations for the dental surface registration (0.83 ± 0.51 mm at implant platform and 1.24 ± 0.68 mm at implant apex) were comparable to the literature. In conclusion, our findings indicate that although sCAIS planned using dental surface image registration was not statistically as accurate as that using fiducial marker registration, its accuracy was satisfactory for clinical use.
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P.A., Nikitin, Nudnov N.V., Znamenskiy I.A., Azimov R.H., Kharina D.S., and Kudryavtsev A.D. "ESTIMATION OF CORRECT MEASUREMENT OF THE TITANIUM RETAINED IMPLANTS AREA BY CT EXPERIMENTAL MODEL." Global problems of modernity 3, no. 1 (April 20, 2022): 59–63. http://dx.doi.org/10.26787/nydha-2713-2048-2022-3-1-59-63.
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Annotation: This article presents the results of evaluating the measurement of the area of titanium mesh implants using computed tomography (CT) data based on the use of an experimental model. Hernioplasty using mesh implants is a modern method of treating hernias of the anterior abdominal wall. The most common complication of hernia surgery is hernia recurrence. The main reason for the development of recurrence is the discrepancy between the size of the implant and the hernial defect, which may occur due to a decrease in the size of the mesh after its installation. CT can be used to assess changes in mesh size. The study showed that the dimensions obtained because of non-invasive measurement of the mesh implant by CT did not significantly differ from the dimensions of the implant obtained intraoperatively. Thus, CT is a highly effective method for assessing the size of titanium mesh implants and can be used in clinical practice.
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Liu, Xiaqing, Fang Pang, Ying Li, Hui Jia, Xiaohua Cui, Yuan Yue, Xuelian Yang, and Qi Yang. "Effects of Different Positions and Angles of Implants in Maxillary Edentulous Jaw on Surrounding Bone Stress under Dynamic Loading: A Three-Dimensional Finite Element Analysis." Computational and Mathematical Methods in Medicine 2019 (December 17, 2019): 1–9. http://dx.doi.org/10.1155/2019/8074096.
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Purpose. To evaluate the effects of different placements of mesial implants and different angles of distant implants in maxillary edentulous jaws on the stress on the implant and the surrounding bone tissue under dynamic loading. Materials and Methods. Cone beam computed tomography was used to acquire images of maxillary edentulous jaws. Using Mimics 17.0, Geomagic, and Unigraphics NX8.5 software, three-dimensional models were established: two mesial implants were placed vertically in the anterior region of the maxilla (bilateral central incisor, lateral incisor, and canine), and two distant implants were placed obliquely in the bilateral second premolar area at different inclined angles (15°, 30°, and 45°). The established models were designated I–IX. The models were subjected to dynamic load using Abaqus 6.12, with the working side posterior teeth loading of 150 N and simulation cycle of 0.875 s. Results. During the second to fourth phases of the mastication cycle, the stress was mainly concentrated on the neck of the distal implant. The stress of the distal implants was greater than that of mesial implants. Stress levels peaked in the third stage of the cycle. The stress of the distal cortical bone of distal implant of Model I reached the maximum of 183.437 MPa. The stress of the distal cortical bone and cancellous bone of distal implant of Model VIII represented the minima (62.989 MPa and 17.186 MPa, respectively). Conclusions. Our models showed optimal stress reductions when the mesial implants were located in the canine region and the distal implants tilted 30°.
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Park, Hyung Jun, Tae Soo Bae, Seung-Baik Kang, Hyeong Ho Baek, Moon Jong Chang, and Chong Bum Chang. "A three-dimensional finite element analysis on the effects of implant materials and designs on periprosthetic tibial bone resorption." PLOS ONE 16, no. 2 (February 10, 2021): e0246866. http://dx.doi.org/10.1371/journal.pone.0246866.
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Introduction Implant material is a more important factor for periprosthetic tibial bone resorption than implant design after total knee arthroplasty (TKA). The virtual perturbation study was planned to perform using single case of proximal tibia model. We determined whether the implant materials’ stiffness affects the degree of periprosthetic tibial bone resorption, and whether the effect of material change with the same implant design differed according to the proximal tibial plateau areas. Materials and methods This three-dimensional finite element analysis included two cobalt-chromium (CoCr) and two titanium (Ti) tibial implants with different designs. They were implanted into the proximal tibial model reconstructed using extracted images from computed tomography. The degree of bone resorption or formation was measured using the strain energy density after applying axial load. The same analysis was performed after exchanging the materials while maintaining the design of each implant. Results The degree of periprosthetic tibial bone resorption was not determined by the type of implant materials alone. When the implant materials were changed from Ti to CoCr, the bone resorption in the medial compartment increased and vice versa. The effect of material composition’s change on anterior and posterior areas varied accordingly. Conclusions Although the degree of bone resorption was associated with implant materials, it differed depending on the design of each implant. The effect on the degree of bone resorption according to the materials after TKA should be evaluated while concomitantly considering design.
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Çetindağ, Aykut, and Belgin Gülsün. "Examination of the stresses of the implants applied to the atrophic edentulous maxilla on the maxillary bone." International Dental Research 11, Suppl. 1 (September 30, 2021): 210–15. http://dx.doi.org/10.5577/intdentres.2021.vol11.suppl1.30.
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Aim: In advanced atrophy of the posterior maxilla, applied zygoma implants increase the success of the surgical procedure by reducing morbidity and procedure time. In our study, using tomographic records, a model with posterior atrophy was obtained in a computer environment, and zygomatic and dental implants in different numbers and localizations were applied to this model. The aim of our study was to choose the most accurate surgical planning according to the stresses arising from the applied forces.
Methodology: In our study, one zygoma implant on the right and left in Group 1, two zygoma implants in Group 2, one zygoma implant in Group 3 and one dental implant in the first premolar tooth area, one zygoma implant in Group 4 and one dental implant in the lateral tooth area and one zygoma implant in Group 5 and one dental implant in the lateral and a first premolar tooth area were applied. 150 N were applied vertically to the prosthetic superstructure from the lateral tooth, 1st premolar tooth, 1st molar tooth and 2nd molar tooth. As a result of the applied forces, the maximum stress values in the maxilla molar region were examined by finite element stress analysis.
Results: In our study, it was observed that Group 1 had the highest stress value, followed by Group 3. Stress values in Groups 2, 4 and 5 were low and they were measured close to each other.
Conclusion: As a result of our study, it was seen that zygomatic and dental implants applied in addition to the zygomatic implant reduce stress and the localization of dental implants affect the stress values.
How to cite this article: Gülsün B, Çetindağ A. Examination of the stresses of the implants applied to the atrophic edentulous maxilla on the maxillary bone. Int Dent Res 2021;11(Suppl.1):210-5. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.30
Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.
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Mulyantoro, Inu, Oktoria Indrapraja, Widjiati Widjiati, and Noor Pramono Noerpramana. "Effect of Metformin on Bcl-2/Bax Expression Ratio and Endometrial Implants: A Mouse Model in Endometriosis Study." Journal of Biomedicine and Translational Research 6, no. 2 (August 18, 2020): 53–58. http://dx.doi.org/10.14710/jbtr.v6i2.8113.
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Background: Endometriosis is a gynaecological disorder characterised by the presence of endometrial tissue outside the uterine cavity. Apoptosis, regulated by the balance of Bcl-2/Bax, plays an important role in the endometrial improvement. Metformin, an insulin sensitizer that is known to have beneficial effect in the endometriosis treatment, is expected to lower Bcl-2/Bax expression ratio and reduce endometrial implants.Objective: To explore the effect of metformin on the Bcl-2/Bax expression ratio and endometrial implant area of endometriosis-induced mice.Methods: This experimental study used 3-month old 33 BALB/c mice of endometriosis that were randomly and equally divided into three groups (P0, P1, and P2). On the 15th day, the P0 group was first terminated for Bcl-2/Bax examination and the size of endometrial implants. The P1 group was given aquabidest, whereas the P2 group was given metformin 4 mg/day for 14 days. The immunohistochemistry of Bcl-2/Bax expression were performed from cavum abdomen and pelvis peritoneal tissues of the mice and measured by the Remmele Scale Index, whereas the extracted mice’ endometrial implants were analysed with computer tracing method. All data normality test was calculated with Shapiro-Wilk test. The mean difference test of all groups was analysed using the one-way ANOVA test, whereas the mean difference test between groups was completed using the Unpaired T-test (LSD/Least Significance Difference).Results: The Bcl-2/Bax expression ratio and endometrial implant area in the P2 group were significantly lower compared to P0 and P1 (p<0.001). There were no significant differences in the Bcl-2/Bax expression ratio or endometrial implant area in P0 and P1 (p>0.05)Conclusion: Metformin may be a potential effective drug treatment for endometriosis by decreasing Bcl-2/Bax expression ratio and endometrial implants.
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Wang, Miaozhen, Xiaohui Rausch-Fan, Yalin Zhan, Huidan Shen, and Feng Liu. "Comparison of Implant Placement Accuracy in Healed and Fresh Extraction Sockets between Static and Dynamic Computer-Assisted Implant Surgery Navigation Systems: A Model-Based Evaluation." Materials 15, no. 8 (April 11, 2022): 2806. http://dx.doi.org/10.3390/ma15082806.
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The aim of this model-base study was to compare the accuracy of implant placement between static and dynamic computer-assisted implant surgery (CAIS) systems in a fresh extraction socket and healed ridge. A randomized in vitro study was conducted. Twenty 3D-printed maxillary models and 80 implants were used. One experienced researcher placed the implants using either the static navigation or dynamic navigation system. Accuracy was measured by overlaying the real position in the postoperative CBCT on the virtual presurgical placement of the implant in a CBCT image. Descriptive and bivariate analyses of the data were performed. In the fresh sockets, the mean deviation was 1.24 ± 0.26 mm (entry point), 1.69 ± 0.34 mm (apical point), and 3.44 ± 1.06° (angle discrepancy) in the static CAIS group, and 0.60 ± 0.29 mm, 0.78 ± 0.33 mm, and 2.47 ± 1.09° in the dynamic CIAS group, respectively. In the healed ridge, the mean deviation was 1.09 ± 0.17 mm and 1.40 ± 0.30 mm, and 2.12 ± 1.11° in the static CAIS group, and 0.80 ± 0.29 mm, 0.98 ± 0.37 mm, and 1.69 ± 0.76° in the dynamic CIAS group, respectively. Compared with the static CAIS system, the dynamic CAIS system resulted in significantly lower entry and apical errors in both fresh sockets and healed ridges. Differences in bone morphology therefore seem to have little effect on accuracy in the dynamic CAIS group.
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Maslov, Leonid, Alexey Borovkov, Irina Maslova, Dmitriy Soloviev, Mikhail Zhmaylo, and Fedor Tarasenko. "Finite Element Analysis of Customized Acetabular Implant and Bone after Pelvic Tumour Resection throughout the Gait Cycle." Materials 14, no. 22 (November 21, 2021): 7066. http://dx.doi.org/10.3390/ma14227066.
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The aim of this paper is to investigate and compare the stress distribution of a reconstructed pelvis under different screw forces in a typical walking pattern. Computer-aided design models of the pelvic bones and sacrum made based on computer tomography images and individually designed implants are the basis for creating finite element models, which are imported into ABAQUS software. The screws provide compression loading and bring the implant and pelvic bones together. The sacrum is fixed at the level of the L5 vertebrae. The variants of strength analyses are carried out with four different screw pretension forces. The loads equivalent to the hip joint reaction forces arising during moderate walking are applied to reference points based on the centres of the acetabulum. According to the results of the performed analyses, the optimal and critical values of screw forces are estimated for the current model. The highest stresses among all the models occurred in the screws and implant. As soon as the screw force increases up to the ultimate value, the bone tissue might be locally destroyed. The results prove that the developed implant design with optimal screw pretension forces should have good biomechanical characteristics.
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Kümbüloğlu, Övül, Beril Koyuncu, Gözde Yerlioğlu, Nadin Al-Haj Husain, and Mutlu Özcan. "Stress Distribution on Various Implant-Retained Bar Overdentures." Materials 15, no. 9 (April 30, 2022): 3248. http://dx.doi.org/10.3390/ma15093248.
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The purpose of this study was to evaluate the effects of various fabrication techniques and materials used in implant-supported mandibular overdentures with a Hader bar attachment over added stress distribution. Three-dimensional geometric solid models, consisting of two implants (3.3 mm × 12 mm) placed at the bone level on both mandibular canine regions and a Hader bar structure, were prepared. Model 1 simulated a bar retentive system made from Titanium Grade 5 material by Computer Numerical Control (CNC) milling technique without using any converting adapter/multi-unit element on the implants, while Model 2 simulated the same configuration, but with converting adapters on the implants. Model 3 simulated a bar retentive system made from Cobalt-Chromium material, made by using conventional casting technique with converting adapters on the implants. Static loads of 100 Newton were applied on test models from horizontal, vertical and oblique directions. ANSYS R15.0 Workbench Software was used to compare Von Mises stress distribution and minimum/maximum principal stress values, and the results were evaluated by using Finite Element Analysis method. As a result, the highest stress distribution values under static loading in three different directions were obtained in Model 1. Stress was observed intensely around the necks of the implants and the surrounding cortical bone areas in all models. In scope of the results obtained, using converting adapters on implants has been considered to decrease transmission of forces onto implants and surrounding bone structures, thus providing a better stress distribution. It has also been observed that the type of material used for bar fabrication has no significant influence on stress values in those models where converting adapters were used.
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Yuan, Fusong, Yao Sun, Lei Zhang, and Yuchun Sun. "Accuracy of chair-side fused-deposition modelling for dental applications." Rapid Prototyping Journal 25, no. 5 (June 10, 2019): 857–63. http://dx.doi.org/10.1108/rpj-04-2018-0082.
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Purpose The purpose of this paper is to establish a chair-side design and production method for a tooth-supported fixed implant guide and to evaluate its accuracy. Design/methodology/approach Three-dimensional (3D) data of the alveolar ridge, adjacent teeth and antagonistic teeth were acquired from models of the edentulous area of 30 patients. The implant guides were then constructed using self-developed computer-aided design software and chair-side fused deposition modelling 3D-printing and positioned on a dental model. A model scanner was used to acquire 3D data of the positioned implant guides, and the overall error was then evaluated. Findings The overall error was 0.599 ± 0.146 mm (n = 30). One-way ANOVA revealed no statistical differences among the 30 implant guides. The gap between the occlusal surface of the teeth covering and the tissue surface of the implant guide was measured. The maximum gap after positioning of the implant guide was 0.341 mm (mean, 0.179 ± 0.019 mm). The implanted axes of the printed implant guide and designed guide were compared in terms of overall, lateral and angular error, which were 0.104 ± 0.004 mm, 0.097 ± 0.003 mm, and 2.053° ± 0.017°, respectively. Originality/value The results of this study demonstrated that the accuracy of a new chair-side tooth-supported fixed implant guide can satisfy clinical requirements.
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Lam, Griselda, and Sun-Young Kim. "Three-Dimensional Computer-Assisted Surgical Planning and Use of Three-Dimensional Printing in the Repair of a Complex Articular Femoral Fracture in a Dog." VCOT Open 01, no. 01 (July 2018): e12-e18. http://dx.doi.org/10.1055/s-0038-1676062.
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Objective The main purpose of this study was to describe the use and benefits of 3-dimensional (3D) computer-assisted surgical planning (CASP) and printing in a complex articular fracture repair in a dog. Study Design Case report. Animals Client-owned dog. Results One dog with a closed, severely comminuted, distal femoral supracondylar and bicondylar fracture underwent a preoperative computed tomography scan. Three-dimensional CASP was performed using computer-aided design software. Three-dimensional CASP allowed for visualization of the fracture fragments and virtual surgery, including reduction of the fragments and implant placement. A 3D model of the affected femur was printed and a bone plate was pre-contoured to the model. Intraoperative fracture reduction and stabilization were performed without complications. Postoperative radiographs revealed successful execution of the planned procedure. Subsequent radiographs and clinical examination indicated that bone healing was achieved with return to normal function of the limb. Three-dimensional CASP and the printed 3D model allowed for improved understanding of the anatomical relationship between fracture fragments, preoperative implant selection and contouring, and the ability to practice fracture reduction and implant placement preoperatively. The model was also used for client education, and to teach students and residents. Conclusion Three-dimensional CASP and printed models are valuable tools in the preoperative planning of complex fracture repairs, educating clients and teaching students and residents.
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Devika, D., and G. Arumaikkannu. "Study on Influence of Implant Thickness and Fixation Position on Implant Stability Using Finite Element Analysis." Journal of Biomimetics, Biomaterials and Tissue Engineering 9 (January 2011): 47–55. http://dx.doi.org/10.4028/www.scientific.net/jbbte.9.47.
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Patient anatomy specific orthopaedic implant design, fabrication and identification of the most suitable position to fix implants onto bone fractures are challenging problems for surgeons to overcome of the existing shortcomings of commercially available implants. In this work, a 3D finite element model of the left tibial bone of an adult male is developed from Computed Tomography scan images. Proximal tibial fracture type B1 (as per Association for the Study of Internal Fixation) is simulated on the bone model. A geometry specific implant is obtained in order to promote better bone ingrowths and uniform stress distribution, by extracting the surface features of the bone. Finite Element Analysis is performed to evaluate and compare the mechanical properties such as stress, strain and displacement of the bone and implant of four various thicknesses which are fixed at two different positions. The design objectives such as low stress and displacement combination is obtained through the antero-lateral position with 1.8 mm implant thickness. Various material properties are assigned to cortical, cancellous, trabecular regions of the bone and to implants made up of titanium alloy. The results obtained from the Finite Element Analysis are used to evaluate the stability and suitability of the implant for that particular fracture.
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Basaruddin, Khairul Salleh, and Ruslizam Daud. "The Effect of Trabecular Bone on the Mechanical Response of Human Mandible with Implant." Applied Mechanics and Materials 695 (November 2014): 588–91. http://dx.doi.org/10.4028/www.scientific.net/amm.695.588.
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This study aims to investigate the influence of trabecular bone in human mandible bone on the mechanical response under implant load. Three dimensional voxel finite element (FE) model of mandible bone was reconstructed from micro-computed tomography (CT) images that were captured from bone specimen. Two FE models were developed where the first consists of cortical bone, trabecular bone and implants, and trabecular bone part was excluded in the second model. A static analysis was conducted on both models using commercial software Voxelcon. The results suggest that trabecular bone contributed to the strength of human mandible bone and to the effectiveness of load distribution under implant load.
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Singare, Se Kou, Li Wang, Shou Yan Zhong, Guang Hui Xu, Wei Ping Wang, and Jian Jun Zhou. "Fabrication of Maxillofacial Implant Using CAD CAM System." Advanced Materials Research 146-147 (October 2010): 353–56. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.353.
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We present an approach that combines Computer Tomography (CT), reverse engineering (RE) and rapid prototyping (RP) for individual implant production in maxillofacial surgery. 3D acquisition of the patient’s skull is performed, after acquisition of data; an individual computer-based 3D model of the bony defect is generated. These data are transferred into RE software to create the implant using a computer-aided design (CAD) model, which is directed into the RP machine for the production of the physical model. The implant is then directly used in investment casting such as “Quick Cast” pattern to produce the titanium model. In the clinical reports presented here, reconstructions of one patient with mandible bone defects were performed using this method. The custom prostheses perfectly fit the defects during the operations, and surgery time was reduced.
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Leelatian, Leena, Panjit Chunhabundit, Phingphol Charoonrut, and Pattapon Asvanund. "Induction of Osseointegration by Nacre in Pigs." Molecules 27, no. 9 (April 20, 2022): 2653. http://dx.doi.org/10.3390/molecules27092653.
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Nacre is a biomaterial that has shown osteoinductive and osteoconductive properties in vitro and in vivo. These properties make nacre a material of interest for inducing bone regeneration. However, information is very limited regarding the introduction of nacre to dental implant surgery for promoting osteogenesis. This study investigated the potential of nacre powder for peri-implant bone regeneration in a porcine model. Ninety-six dental implants were placed into the tibia of twelve male domestic pigs. The dental implants were coated with nacre powder from the giant oyster before implantation. Implantations without nacre powder were used as control groups. Euthanization took place at 2, 4 and 6 weeks after implantation, after which we measured bone-to-implant contact (BIC) and bone volume density (BVD) of the implanted bone samples using micro-computed tomography (micro-CT), and examined the histology of the surrounding bone using histological sections stained with Stevenel’s blue and Alizarin red S. The micro-CT analyses showed that the BIC of dental implantations with nacre powder were significantly higher than those without nacre powder, by 7.60%. BVD of implantations with nacre powder were significantly higher than those without nacre powder, by 12.48% to 13.66% in cortical bone, and by 3.37% to 6.11% in spongy bone. Histological study revealed more peri-implant bone regeneration toward the surface of the dental implants after implantation with nacre powder. This was consistent with the micro-CT results. This study demonstrates the feasibility of using nacre to promote peri-implant bone regeneration in dental implantation.
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Al Qahtani, Waleed M. S. "Effect of Variable Implant Tip Distances on Stress Distribution around the Mental Foramen: A Finite Element Analysis." Open Access Macedonian Journal of Medical Sciences 9, no. D (October 14, 2021): 202–9. http://dx.doi.org/10.3889/oamjms.2021.6407.
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AIM: This study aimed to evaluate the effect of gap between traditional implant tip and mental nerve using finite element analysis. METHODS: Four finite element models (FEM) were prepared for dummy crowns that were supported by traditional implants that were placed vertically in laser scanned mandibular bone geometry. Where gap distance were designed to be 1.5, 2.0, 2.5, and 3.0 mm. Dummy crown, 50 μm cement layer, and implant complex models’ components were modeled in 3D on engineering computer-aided design (CAD)/CAD (computer-aided manufacturer) software formerly collected in Finite Element Analysis package. Each model was subjected to two loading cases as 150N compressive load at central fossa, and 50N Oblique (45º) load at central fossa of the dummy crown. RESULTS: Good agreement of the FEM was obtained when compared to similar studies. Under applied study loads, all resulting values of stresses and deformations of the four models were within physiological limits. The obtained data showed no effect on cortical bone, implant complex, cement layer, and dummy crown to changing of gap distance. In addition, the cancellous bone, especially around the mental canal, was considerably affected by the variation in that gap distance. CONCLUSION: Increasing the gap distance between the dental implant tips may reduce the stress and deformation around the mental canal. Minimum gap distance of order 2.5 mm is recommended to reduce stresses and deformations around canal to favorable limits, while more gap distance is also recommended with larger bone geometries.
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González Rueda, Juan Ramón, Irene García Ávila, Víctor Manuel de Paz Hermoso, Elena Riad Deglow, Álvaro Zubizarreta-Macho, Jesús Pato Mourelo, Javier Montero Martín, and Sofía Hernández Montero. "Accuracy of a Computer-Aided Dynamic Navigation System in the Placement of Zygomatic Dental Implants: An In Vitro Study." Journal of Clinical Medicine 11, no. 5 (March 5, 2022): 1436. http://dx.doi.org/10.3390/jcm11051436.
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The objective of this in vitro study was to evaluate and compare the accuracy of zygomatic dental implant (ZI) placement carried out using a dynamic navigation system. Materials and Methods: Forty (40) ZIs were randomly distributed into one of two study groups: (A) ZI placement via a computer-aided dynamic navigation system (n = 20) (navigation implant (NI)); and (B) ZI placement using a conventional free-hand technique (n = 20) (free-hand implant (FHI)). A cone-beam computed tomography (CBCT) scan of the existing situation was performed preoperatively to plan the surgical approach for the computer-aided study group. Four zygomatic dental implants were placed in anatomically based polyurethane models (n = 10) manufactured by stereolithography, and a postoperative CBCT scan was performed. Subsequently, the preoperative planning and postoperative CBCT scans were added to dental implant software to analyze the coronal entry point, apical end point, and angular deviations. Results were analyzed using the Student’s t-test. Results: The results showed statistically significant differences in the apical end-point deviations between FHI and NI (p = 0.0018); however, no statistically significant differences were shown in the coronal entry point (p = 0.2617) or in the angular deviations (p = 0.3132). Furthermore, ZIs placed in the posterior region showed more deviations than the anterior region at the coronal entry point, apical end point, and angular level. Conclusions: The conventional free-hand technique enabled more accurate placement of ZIs than the computer-assisted surgical technique. In addition, placement of ZIs in the anterior region was more accurate than that in the posterior region.