Digital Technologies for Dental Implant Treatment Planning and Guided Surgery

Automatic planning of maxillary anterior dental implant based on prosthetically guided and pose evaluation indicator

PURPOSE

Preoperative planning of maxillary anterior dental implant is a prerequisite to ensuring that the implant achieves the proper three-dimensional (3D) pose, which is essential for its long-term stability. However, the current planning process is labor-intensive and subjective, relying heavily on the surgeon's experience. Consequently, this paper proposes an automatic method for computing the optimal pose of the dental implant.

METHODS

The method adopts the principle of prosthetically guided dental implant placement. Initially, the prosthesis coordinate system is established to determine the implant candidate orientations. Subsequently, virtual slices of the maxilla in the buccal-palatal direction are generated according to the prosthesis position. By extracting feature points from the virtual slices, the implant candidate starting points are acquired. Then, a candidate pose set is obtained by combining these candidate starting points and orientations. Finally, a pose evaluation indicator is introduced to determine the optimal implant pose from this set.

RESULTS

Twenty-two cases were utilized to validate the method. The results show that the method could determine an ideal pose for the dental implant, with the average minimum distance between the implant and the left tooth root, the right tooth root, the palatal side, and the buccal side being 2.57 ± 0.53 mm, 2.59 ± 0.65 mm, 0.74 ± 0.19 mm, 1.83 ± 0.16 mm, respectively. The planning time was less than 9 s.

CONCLUSION

Unlike manual planning, the proposed method can efficiently and accurately complete maxillary anterior dental implant planning, providing a theoretical analysis of the success rate of the implant. Thus, it has great potential for future clinical application.

Deep learning for the identification of ridge deficiency around dental implants

OBJECTIVES

This study aimed to use a deep learning (DL) approach for the automatic identification of the ridge deficiency around dental implants based on an image slice from cone-beam computerized tomography (CBCT).

MATERIALS AND METHODS

Single slices crossing the central long-axis of 630 mandibular and 845 maxillary virtually placed implants (4-5 mm diameter, 10 mm length) in 412 patients were used. The ridges were classified based on the intraoral bone-implant support and sinus floor location. The slices were either preprocessed by alveolar ridge homogenizing prior to DL (preprocessed) or left unpreprocessed. A convolutional neural network with ResNet-50 architecture was employed for DL.

RESULTS

The model achieved an accuracy of >98.5% on the unpreprocessed image slices and was found to be superior to the accuracy observed on the preprocessed slices. On the mandible, model accuracy was 98.91 ± 1.45%, and F1 score, a measure of a model's accuracy in binary classification tasks, was lowest (97.30%) on the ridge with a combined horizontal-vertical defect. On the maxilla, model accuracy was 98.82 ± 1.11%, and the ridge presenting an implant collar-sinus floor distance of 5-10 mm with a dehiscence defect had the lowest F1 score (95.86%). To achieve >90% model accuracy, ≥441 mandibular slices or ≥592 maxillary slices were required.

CONCLUSIONS

The ridge deficiency around dental implants can be identified using DL from CBCT image slices without the need for preprocessed homogenization. The model will be further strengthened by implementing more clinical expertise in dental implant treatment planning and incorporating multiple slices to classify 3-dimensional implant-ridge relationships.

Accuracy of Microimplant Placement Using a 3D Guide Plate for Orthodontic Anchorage

This study aimed to design a three-dimensional (3D) guide plate using computer-aided design and a 3D printing system for precise implantation of microimplants for orthodontic treatment and investigate the accuracy and feasibility of a 3D guide plate in clinical practice. A total of 30 microimplants were placed in 15 patients in the Department of Stomatology, Affiliated Hospital of Jiangnan University. Before surgery, DICOM data from cone-beam computed tomography (CBCT) scans and STereoLithography data from the 3D model scan were imported to 3Shape Dental System. Data fitting and matching were performed, and 3D guide plates were designed primarily focusing on the thickness of guide plates, amount of concave compensation, and dimensions of the ring. Assist implantation method was used to place the microimplants, and postoperative CBCT images were used to evaluate the position and implantation angle. The feasibility of placing microimplants and precise implantation guided by the 3D guide plate. CBCT data before and after the placement of microimplants were compared. Regarding the secure positioning of microimplants based on CBCT data, 26 implants were categorized as Grade i, four as Grade ii, and none as Grade iii. No loosening of microimplants 1 and 3 months after surgery was reported. The implantation of microimplants is more accurate under the guidance of a 3D guide plate. This technology can achieve accurate implant positioning, thus ensuring safety, stability, and improved success rates after implantation.

Accuracy Analysis of Computer-Assisted and Guided Dental Implantology by Comparing 3D Planning Data and Actual Implant Placement in a Mandibular Training Model: A Monocentric Comparison between Dental Students and Trained Implantologists

The aim of this study was to investigate how precisely implantation can be realized by participants on a phantom head according to preliminary planning. Of particular interest here was the influence of participants' previous knowledge and surgical experience on the precision of the implant placement. The placed implants were scanned using an intraoral scanner, saved as STL files, and superimposed with the 3D-planned implant placement. Deviations from the planning were indicated in millimeters and degrees. We were able to show that on average, the deviations from computer-assisted 3D planning were less than 1 mm for implantologists, and the students also did not deviate more than 1.78 mm on average from 3D planning. This study shows that guided implantology provides predictable and reproducible results in dental implantology. Incorrect positioning, injuries to anatomical structures, and implant positions that cannot be prosthetically restored can thus be avoided.

Three-dimensionally printed implant surgical guide-related experience, knowledge, attitude, and professional behaviors among 2028 dentists in China: A cross-sectional study

STATEMENT OF PROBLEM

Research on the current place of 3-dimensionally printed implant surgical guides (3D-ISGs) among practicing dentists worldwide is lacking, with little research focused on dentists' experience, knowledge, attitude, or professional behavior related to 3D-ISG or on the main obstacle to adoption.

PURPOSE

The purpose of this cross-sectional study was to identify the adoption of 3D-ISG in dental practice in China and to determine factors that influence its further application and dentists' attitudes and willingness.

MATERIAL AND METHODS

Semistructured questionnaires were sent to a sample of Chinese dentists composed of users and nonusers of 3D-ISG. The questionnaires were displayed and distributed through a professional online survey system (http://www.wjx.cn) and a social media platform (WeChat). The responses were analyzed with multivariable generalized equations, and the effect of various demographic variables was determined, including dentist experience, academic degree, and type of practice (public or private).

RESULTS

A total of 2028 valid questionnaires were collected. In dental practice, 39.3% of the respondents used 3D-ISG. Respondents with a PhD (62.4%) used the 3D-ISG more than twice as frequently as respondents with a junior college degree or below (31.8%). The majority of the members of implantology departments (81.7%) applied 3D-ISG, but doctors in other departments used it at a rate of less than half. The 3D-ISG was most frequently used in the maxillary anterior area (78.4%), followed by the edentulous maxilla and mandible (61.0% and 60.5%, respectively). The main barriers were high initial cost, complex and time-consuming digital design, and lack of expertise in the proper use of 3D-ISG.

CONCLUSIONS

Most dentists did not use 3D-ISG in dental practice. The 3D-ISG application rate was significantly associated with sex, academic degree, years of dental practice, department, monthly income, and type of healthcare facility. To improve the popularity of 3D-ISG, particularly among dentists without advanced degrees, it would be important to optimize the digital design software program and provide sufficient training.

Performance of novice versus experienced surgeons for dental implant placement with freehand, static guided and dynamic navigation approaches

Lack of evidence exists related to the investigation of the accuracy and efficacy of novice versus experienced practitioners for dental implant placement. Hence, the following in vitro study was conducted to assess the accuracy of implant positioning and self-efficacy of novice compared to experienced surgeons for placing implant using freehand (FH), pilot drill-based partial guidance (PPG) and dynamic navigation (DN) approaches. The findings revealed that DN significantly improved the angular accuracy of implant placement compared with FH (P < 0.001) and PPG approaches (P < 0.001). The time required with DN was significantly longer than FH and PPG (P < 0.001), however, it was similar for both novice and experienced practitioners. The surgeon's self-confidence questionnaire suggested that novice practitioners scored higher with both guided approaches, whereas experienced practitioners achieved higher scoring with PPG and FH compared to DN. In conclusion, implant placement executed under the guidance of DN showed high accuracy irrespective of the practitioner's experience. The application of DN could be regarded as a beneficial tool for novices who offered high confidence of using the navigation system with the same level of accuracy and surgical time as that of experienced practitioners.

The effect of implant surgery experience on the learning curve of a dynamic navigation system: an in vitro study

BACKGROUND

Dynamic navigation systems have a broad application prospect in digital implanting field. This study aimed to explore and compare the dynamic navigation system learning curve of dentists with different implant surgery experience through dental models.

METHODS

The nine participants from the same hospital were divided equally into three groups. Group 1 (G1) and Group 2 (G2) were dentists who had more than 5 years of implant surgery experience. G1 also had more than 3 years of experience with dynamic navigation, while G2 had no experience with dynamic navigation. Group 3 (G3) consisted of dentists with no implant surgery experience and no experience with dynamic navigation. Each participant sequentially placed two implants (31 and 36) on dental models according to four practice courses (1-3, 4-6, 7-9, 10-12 exercises). Each dentist completed 1-3, 4-6 exercises in one day, and then 7-9 and 10-12 exercises 7 ± 1 days later. The preparation time, surgery time and related implant accuracy were analyzed.

RESULTS

Three groups placed 216 implants in four practice courses. The regressions for preparation time (F = 10.294, R² = 0.284), coronal deviation (F = 4.117, R² = 0.071), apical deviation (F = 13.016, R² = 0.194) and axial deviation (F = 30.736, R² = 0.363) were statistically significant in G2. The regressions for preparation time (F = 9.544, R² = 0.269), surgery time (F = 45.032, R² = 0.455), apical deviation (F = 4.295, R² = 0.074) and axial deviation (F = 21.656, R² = 0.286) were statistically significant in G3. Regarding preparation and surgery time, differences were found between G1 and G3, G2 and G3. Regarding implant accuracy, differences were found in the first two practice courses between G1 and G3.

CONCLUSIONS

The operation process of dynamic navigation system is relatively simple and easy to use. The linear regression analysis showed there is a dynamic navigation learning curve for dentists with or without implant experience and the learning curve of surgery time for dentists with implant experience fluctuates. However, dentists with implant experience learn more efficiently and have a shorter learning curve.

Dental innovations which will influence the oral health care of baby boomers

From the widespread use of smartphones and tablets to the multitude of applications available, older adults are showing an interest in utilizing technology to maintain their independence and to improve their quality of life. As technology continues to advance and be incorporated into many day-to-day activities, the baby boom generation will see these changes affecting the way they access and utilize dental services. Innovative toothbrushes and chemotherapeutics are continuing to be developed and utilized by many older adults. Within the dental office, older adults are seeing greater application of technology in every day dental procedures. These include the use of teledentistry, artificial intelligence (AI), innovative restorative materials, digitization of fixed and removable prosthodontics, cone beam computed tomography (CBCT) scans to guide dental implant placement and endodontic procedures. There is also new technology to aid in cancer detection and shielding during cancer treatment. Improved communication between the medical and dental fields has become increasingly necessary to facilitate effective patient care and a few innovative healthcare systems have begun to consolidate these services. Overall, the baby boom generation will continue to see dental innovations that will change the way they experience everyday life and dental services.

Clinical study of dynamic real-time navigation assisted immediate implant without flapping in the esthetic zone

OBJECTIVE

The purpose of this study is to investigate the clinical effect of Dynamic real-time navigation to assist immediate implant without flapping in the esthetic zone.

METHODS

Eight patients who underwent immediate implantation in the aesthetic area were included. A total of 11 implants were implanted using dynamic real-time navigation system combined with non-flap technology. Clinical indicators including implant deviation, initial stability, alveolar bone absorption, implant success rate, pink esthetic score (PES), Papilla index score (PIS), and the thickness of labial side bone plate of the implant were recorded.

RESULTS

The deviation between the actual implant position and the preoperative design was (0.76±0.08) mm at the top, (1.11±0.18) mm at the root, (0.90±0.16) mm at the depth, and (1.48±0.91)°at the Angle. ISO values of all implants were greater than 59. PES was greater than 8. PIS index was 2 or 3. The average alveolar bone absorption was (0.34±0.09) mm and the thickness of bone plate on the lip of implant was greater than 1.6 mm. The success rate of implantation was 100%.

CONCLUSION

The use of dynamic real-time navigation assisted non-flap implantation in the aesthetic area can effectively reduce implant deviation and improve the aesthetic effect.

A chairside digital radiographic guide for registering digital casts to cone beam computed tomography scans with strong metallic artifacts

Accurate registration of digital casts and cone beam computed tomography (CBCT) scans with strong metallic artifacts is essential for the accuracy of guided implant surgery. This article describes a procedure for mapping digital casts onto CBCT scans containing significant scatter artifacts in the virtual implant planning stage. The technique uses a chairside segmented occlusal wing-like radiographic guide, which is constructed of digital splints fabricated using a desktop 3-dimensional printer and composite resin spheres as markers to accurately superimpose the bimaxillary digital scans onto the CBCT scans in a single procedure. This cost-effective technique is timesaving for clinicians and patients, and the digital information for implant planning can be collected in a single visit.

Guided Approach to Implant Placement, Immediate Provisionalization, and Definitive Restoration: A Case Letter

Replacement of missing teeth is becoming more prevalent, currently with more than 700,000 dental implants being placed every year. Patients seek out dental treatment with the expectations of having procedures performed in the least number of time/visits, for as inexpensive as possible, and at the highest quality. As this continues, clinicians can adapt with changing times and adopt the newer advancements in digital dentistry. This case letter aims to provide readers with insight to integration of digital workflows to optimize patient and clinician outcomes with single tooth implant therapy.

Digital workflow for designing an interim implant-supported restoration with an optimal emergence profile in an open-source software program

The esthetics and emergence profile design of implant-supported restorations in the anterior zone can be challenging. This dental technique describes a digital approach to designing an optimal emergence profile from the implant head to the definitive prosthetic volume with facial cutback for an esthetic implant-supported interim crown. A printed interim implant-supported restoration with an adequate emergence profile and a facial cutback for composite resin layering is obtained.

Reducing errors in guided implant surgery to optimize treatment outcomes

Clinical considerations and treatment criteria in implant placement are constantly evolving. Prosthetically driven implant surgery has become the standard of care to improve short and long-term functional and esthetic outcomes. Therefore, implant position and angulation are planned according to the available bone, anatomical structures, and the requirements of the future prosthetic superstructure. In parallel with these developments, significant progress has been made in data imaging and different software technologies to allow the integration of data within a digital file format. Digitalization in implant surgery enables optimal planning of implant position, as well as the ability to transfer this planning to the surgical field-a process defined as "computer-supported implant planning and guided surgery." The aims of the present review are as follows: (a) to critically appraise the indications and potential "added value" of guided implant surgery, elaborating the main differences between dynamic and static guidance; and (b) to discuss the most important clinical considerations relevant for the different steps of the workflow that might influence the surgical outcome and to offer recommendations on how to avoid or reduce process errors in order to optimize treatment outcomes.

One-Stage Virtual Plan of a Complex Orthodontic/Prosthetic Dental Rehabilitation

In complex dental treatments, a preliminary virtual plan (VP) can minimise the probability of errors and increase the predictability of the achieved result. Digital technologies and artificial intelligence open more opportunities for such planning, as they can be applied at the early stages of clinical examination to develop a simultaneous VP of all stages of treatment. The present clinical case describes a one-stage entire VP combining all the stages of treatment: gnathological, orthodontic, and prosthetic rehabilitation, until the final result. This approach avoids the accumulation errors associated with multistage VP, in which one stage of planning follows the end of a previous stage. One-step VP also allows demonstrating to the patients the expected results of the restoration, which increases their motivation to initiate the treatment.

Three-dimensional inlay-guided endodontics applied in variant root canals: A case report and review of literature

BACKGROUND

Root canal retreatment is common after root canal therapy in clinical situations. Especially, completing the retreatment of variant root canals can be challenging. This is particularly true for the molars located at the end of the dental arch. However, advancements in digital dental diagnosis and treatment techniques can solve these problems. Here, we describe a case of a maxillary second molar with a variant distobuccal root canal treated via a novel “inlay-guided endodontics” technique based on improved computer-generated programs.

CASE SUMMARY

A 63-year-old man complained of a defect in the maxillary left second molar. The tooth, diagnosed with post-treatment endodontic disease, was initially treated by conventional methods, which were ineffective. Our “inlay-guided endodontics” technique was subsequently adopted, with the establishment of a precise integrated three-dimensional (3D) plate model of cone-beam computed tomography data and a digital impression of the dentition. An optimal root canal approach was generated for the “virtual file” in the 3D model. The plate data were imported into a 3D printer and printed. With the help of the guide plate, the file was accurately placed into the cervical third of the distal root canal. The root canal and prosthodontic treatments successfully proceeded subsequently.

CONCLUSION

Our newly developed inlay guide plates may facilitate individualized and minimally invasive root canal treatment.

Preliminary application and evaluation of digital step-by-step tooth-preparation templates

STATEMENT OF PROBLEM

Tooth preparation is a fundamental technique, and inaccurate preparation may lead to excessive irreversible tooth removal or insufficient restorative space. The conventional process depends mostly on operator experience, and variable quality is inevitable. Whether a tooth preparation template would be beneficial, especially for inexperienced dentists, is unclear.

PURPOSE

The purpose of this preliminary study was to evaluate the application of new digitally designed step-by-step templates to guide tooth preparation.

MATERIAL AND METHODS

A laboratory scanner was used to obtain digital scans of dental casts. A 3-dimensional reverse engineering software program was used for the step-by-step digital design. The data for a series of guide templates were imported into a computer-aided manufacturing (CAM) machine for milling. Ten experts and 10 inexperienced dentists prepared teeth on a dentoform in a mannequin head. They were instructed to complete the preparation within 20 minutes both with and without the step-by-step template. The prepared crowns were subsequently scanned with an intraoral scanner, the scans were imported into a preparation evaluation software program, and various indexes were scored. The t test was used to analyze the differences between the 2 methods of tooth preparation in each group (α=.05).

RESULTS

No significant differences were found in total scores with and without the guide templates in the expert group (P=.256), but the scores in the inexperienced group differed significantly between the 2 preparation methods (P<.001). In undercut comparisons, the 2 methods of preparation did not differ significantly in the expert (P=.912) or inexperienced groups (P=.601). However, the scores for taper and occlusal reduction were significantly higher in the inexperienced group when using the guide template (P<.001).

CONCLUSIONS

The new digitally designed step-by-step tooth preparation guide template significantly improved the efficiency and quality of tooth preparation for inexperienced dentists when preparing multiple teeth.

The role of simulator and digital technologies in head and neck reconstruction

This review summarizes the development of digital technology in the field of head and neck surgeries. Advances in digital technology assist surgeons during preoperative planning, where they can simulate their surgeries with improvement in the resulting accuracy of the surgery. In addition to digital technologies having many applications in the surgical field, they can be used in medical devices, surgical and educational models, and tissue engineering.

Radiopaque fiducial markers as an aid to fabrication of an implant surgical guide for a patient with orthodontic brackets: A dental technique

Designing implant surgical guides for patients undergoing orthodontics merely by merging data imaging and communications in medicine (DICOM) files generated from cone beam computed tomography (CBCT) images and standard tessellation language (STL) files generated from surface scanners is challenging because of the inaccuracy caused by metal artifacts. The present technique describes a straightforward and effective method of fabricating a surgical guide with the aid of fiducial markers made from cotton swabs and flowable resin. The implant surgical guide is designed by using a software program after the superimposition of digital scan and CBCT data. This chairside technique provides an accurate, convenient, and cost-effective option for the clinician.

Time-efficiency and cost-analysis comparing three digital workflows for treatment with monolithic zirconia implant fixed dental prostheses: A double-blinded RCT

OBJECTIVES

This double-blinded randomized controlled trial investigated economic performance indicators (EPI) in terms of time-efficiency and production costs of 3-unit monolithic zirconium-dioxide (ZrO2) implant fixed dental prostheses (iFDP) in three different workflows.

METHODS

Twenty patients with two Straumann Tissue-Level-Implants received three iFDPs; two were fabricated in proprietary complete digital workflows with intraoral optical scanning and model-free fabrication with company-related CAD/CAM lab-software while one iFDP was manufactured on digitized casts from conventional impressions. The sequence of impression-taking for the three workflows (TRIOS 3/3Shape [Test-1]; Virtuo Vivo/Dental Wings [Test-2]; Impregum/3M Espe [Control]) was randomly allocated. Sixty iFDPs bonded to ti-base abutments were analyzed. Clinical and technical worksteps for Test-1/Test-2/Control were recorded and evaluated for time-efficiency including cost-analysis (CHF=Swiss Francs) using ANOVA-Tests (significance level α=0.05).

RESULTS

Mean total work time, as the sum of clinical plus technical steps, was 97.5 min (SD ± 23.6) for Test-1, 193.1 min (SD ± 25.2) for Test-2, and 172.6 min (SD ± 27.4) for Control. Times were significantly different between Test-1/Test-2 (p < 0.00001), Test-1/Control (p < 0.00001), and Test-2/Control (p < 0.03610). Technical costs were 566 CHF (SD ± 49.3) for Test-1, 711 CHF (SD ± 78.8) for Test-2, 812 CHF (SD ± 89.6) for Control, and were also significantly different for all comparisons (p < 0.00001).

CONCLUSIONS

Test-1 demonstrated the best performance for time-efficiency, Test-2 revealed the worst result. This indicates that digital workflows are not the same and not necessarily superior to analog workflows of monolithic ZrO2 iFDPs. Complexity decreases by reducing the number of steps following complete digital workflows, resulting in lower production costs compared to the mixed analog-digital workflow with conventional impressions.

CLINICAL SIGNIFICANCE

Complete digital workflows comprising intraoral optical scanning without physical models for treatment with monolithic ZrO2 iFDPs is an efficient alternative to mixed analog-digital workflows with conventional impressions and labside digitization of dental casts.

A Double-Blind Crossover RCT Analyzing Technical and Clinical Performance of Monolithic ZrO2 Implant Fixed Dental Prostheses (iFDP) in Three Different Digital Workflows

This double-blind randomized controlled trial with a crossover design analyzed the technical and clinical performance of three-unit monolithic ZrO₂ implant-fixed dental prostheses (iFDPs), prepared using two complete digital workflows (Test-1, Test-2) and one mixed analog–digital workflow (Control). Each of the 20 study patients received three iFDPs, resulting in 60 restorations for analysis. The quality of the restorations was assessed by analyzing laboratory cross-mounting and calculating the chairside adjustment time required during fitting. All iFDPs could be produced successfully with all three workflows. The highest cross-mounting success rate was observed for the original pairing iFDP/model of the Control group. Overall, 60% of iFDPs prepared with Test-1 workflow did not require chairside adjustment compared with 50% for Test-2 and 30% for Controls. The mean total chairside adjustment time, as the sum of interproximal, pontic, and occlusal corrections was 2.59 ± 2.51 min (Control), 2.88 ± 2.86 min (Test-1), and 3.87 ± 3.02 min (Test-2). All tested workflows were feasible for treatment with iFDPs in posterior sites on a soft tissue level type implant system. For clinical routine, it has to be considered that chairside adjustments may be necessary, at least in every second patient, independent on the workflow used.

Online dental teaching practices during the COVID-19 pandemic: a cross-sectional online survey from China

Background

Coronavirus disease 2019 (COVID-19) emerged in China in December 2019. The COVID-19 pandemic hindered dental education, as school buildings were closed. Online dental teaching provided an alternative teaching tool for dental education. However, the efficiency of online dental teaching and student preferences for online dental teaching are unclear.

Aim

To investigate the satisfaction with online dental teaching practices among undergraduate dental students and standardized resident physician training students during the COVID-19 pandemic in China.

Methods

A total of 104 undergraduate dental students and 57 standardized resident physician training students from Zhejiang University participated in the study. A 12-item survey was conducted. This investigation included the teaching methods received, frequency of classes, degree of satisfaction, preferred teaching method, whether to participate in a course regarding COVID-19 prevention, and the effects of teaching. The percentages were then calculated and evaluated for each item.

Results

A total of 161 students (104 undergraduate dental students and 57 standardized resident physician training students) participated in this survey. All students had online dental classes during the COVID-19 pandemic. Lecture-based learning (LBL), case-based learning (CBL), problem-based learning (PBL), team-based learning (TBL), and research-based learning (RBL) were selected as teaching methods. Students were more satisfied with LBL and CBL than PBL, RBL, and TBL. The majority of students had more than four classes per week. The most selected protective measures were hand washing, wearing masks, and wearing gloves. A total of 46.6% of students participated in courses on COVID-19. After training, the students consciously chose to wear face shields and protective clothing.

Conclusions

Dental students accepted online dental learning during the COVID-19 pandemic. Students preferred LBL and CBL and were satisfied with the classes. Courses on COVID-19 helped students understand how to prevent COVID-19 transmission in the dental clinic.

The Modern and Digital Transformation of Oral Health Care: A Mini Review

Dentistry is a part of the field of medicine which is advocated in this digital revolution. The increasing trend in dentistry digitalization has led to the advancement in computer-derived data processing and manufacturing. This progress has been exponentially supported by the Internet of medical things (IoMT), big data and analytical algorithm, internet and communication technologies (ICT) including digital social media, augmented and virtual reality (AR and VR), and artificial intelligence (AI). The interplay between these sophisticated digital aspects has dramatically changed the healthcare and biomedical sectors, especially for dentistry. This myriad of applications of technologies will not only be able to streamline oral health care, facilitate workflow, increase oral health at a fraction of the current conventional cost, relieve dentist and dental auxiliary staff from routine and laborious tasks, but also ignite participatory in personalized oral health care. This narrative article review highlights recent dentistry digitalization encompassing technological advancement, limitations, challenges, and conceptual theoretical modern approaches in oral health prevention and care, particularly in ensuring the quality, efficiency, and strategic dental care in the modern era of dentistry.

Current Trends in Research on Bone Regeneration: A Bibliometric Analysis

Background

Bone regeneration is a frequent research topic in clinical studies, but macroscopic studies on the clinical application of bone regeneration are rare. We conducted a bibliometric analysis, using international databases, to explore the clinical application and mechanism of bone regeneration, to highlight the relevant research hotspots and prospects. Material and Methods. Scientific reports on bone regeneration published during 2009–2019 were retrieved from PubMed. VOSviewer for cooccurrence keywords and authorship analysis. BICOMB software was used to retrieve high-frequency words and construct a text/coword matrix. The matrix was inputted into gCLUTO software, managed by biclustering analysis, in order to identify hotspots, which could achieve mountain and matrix visualizations. The matrix was also analyzed by using Ucinet 6 software for social network analysis. A strategic diagram was used for further analysis of the research hotspots of bone regeneration by “SCIMAT” software. We searched the Web of Science for relevant articles.

Results

Eighty-nine high-frequency major MeSH terms were obtained from 10237 articles and were divided into 5 clusters. We generated a network visualization map, an overlay visualization mountain map, and a social network diagram. Then, the MeSH terms were subdivided into 7 categories according to each diagram; current research hotspots were identified as scaffold, drug effect, osseointegration in dental implant, guided bone regeneration, factors impacting bone regeneration, treatment of bone and tissue loss, and bone regeneration in dental implants.

Conclusion

BICOMB, VOSviewer, and other bibliometric tools revealed that dental implants, scaffolds, and factors impacting bone regeneration are hot research topics, while scaffolds also hold promise from the perspective of bone tissue regeneration.

The Effects of Distribution of Image Matched Fiducial Markers on Accuracy of Computer-Guided Implant Surgery

PURPOSE

Image registration of the optical intraoral scan to computed tomography image is essential for computer-guided implant surgery. The remaining teeth, which are considered to be congruent structures observed in the scan and radiographic images, are used to perform the image registration. The purpose of this study was to evaluate the effects of the distribution of matching fiducial points on the accuracy of the image registration.

MATERIALS AND METHODS

A partially edentulous model with three anterior remaining teeth was prepared. Two mini dental implants were inserted in the posterior edentulous areas on both sides, and computed tomography and surface scan data were obtained. Three groups were set according to the distribution of the image matching points used: localized distribution, unilateral distribution, and bilateral distribution. Fifteen graduate students performed the registration process in each group using the same image matching method. The accuracy of image registration was evaluated by measuring the geometric discrepancies between the radiographic and registered scan images in the anterior, middle, and posterior regions. One-way and two-way analysis of variance with the Tukey HSD post hoc test were used for statistical analysis (α = 0.05) RESULTS: In general, the registration discrepancy was lowest in the bilateral distribution group, followed by the unilateral distribution and localized distribution groups (p< 0.001). In the regional analysis, the registration error tended to increase as the measurement region moved farther from the matching points. The distribution of the matching points and measurement regions had a statistical interaction in the accuracy of image registration.

CONCLUSION

The accuracy of image registration of the surface scan to the computed tomography is affected by the matching point distribution that can be improved by placing artificial markers in the edentulous areas.

Advantages and limitations of implant surgery with CAD/CAM surgical guides: A literature review

Background

The purpose of this study is to review the available literature associated with implant surgery using computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guides and discuss the advantages and disadvantages of this advanced technique.

Material and Methods

An electronic literature search was conducted in the PubMed database for the relevant information on implant placement with CAD/CAM surgical guides. This review was constructed following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Articles were limited to those published within the past 10 years and in the English language. Only clinical studies were included. Inclusion criteria were: studies including 10 implants or more and studies presenting angular deviations in degrees and linear deviations in millimeter. Observational studies, reviews, animal studies, in vitro studies, case reports, simulation studies were excluded. Nine articles were included for qualitative synthesis.

Results

The initial search detected 61 articles, and after screening abstracts, a total of 15 articles were selected for full-text review. After the full-text analysis of the 15 articles, six articles were excluded as they did not meet inclusion criteria for study design, study population, and implant placement with data presentation for angular and linear deviations. Ultimately, nine articles providing angular and linear deviations between planned and actual placed implants were used in this review. Common problems that may be encountered by clinicians were listed, and recommendations were made on how to avoid those problems.

Conclusions

It has been suggested that although unrealistic expectations are often associated with implant placement with CAD/CAM surgical guides, there is no impeccable accuracy in the clinic. This review demonstrated that the practitioners should be aware of the angular and linear deviations up to 5 ° and 2.3 mm. Therefore, inexperienced dentists should obtain adequate training and be familiar with the basic steps with CAD/CAM surgical guides to avoid complications.

Key words:CAD/CAM, CBCT, implant, stereolithography, surgical guide.

Comparison between flapless and open-flap implant placement: a systematic review and meta-analysis

No consensus has been reached regarding the influence of the flapless and open-flap surgical techniques on the placement of dental implants. This systematic review compared the effects of flapless implant placement and implant placement with elevation of the mucoperiosteal flap in terms of marginal bone loss, implant survival rate and complications rates. This review followed PRISMA guidelines and was registered in PROSPERO with the registration number CRD42017071475. Two independent reviewers performed a comprehensive search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published until December 2017. The search identified 559 references. After a detailed review, 24 studies were assessed for eligibility. A total of 1025 patients who had received a total of 1873 dental implants were included. There were no significant differences between the flapless and open-flap surgical techniques in terms of implant survival rates (P=0.34; risk ratio (RR): 1.36; confidence interval (CI): 0.72-2.56), marginal bone loss (P=0.23; MD: -0.20; CI: -0.52-0.13), or complication rates (P=0.67; RR: 1.10; CI: 0.70-1.73). The current meta-analysis showed that the implant survival rate, marginal bone levels, and complications of flapless surgery were similar to those of open-flap surgery over a mean follow-up period of 21.62 months.

Accuracy, reproducibility, and dimensional stability of additively manufactured surgical templates

STATEMENT OF PROBLEM

Additively manufactured surgical templates are commonly used for computer-guided implant placement. However, their accuracy, reproducibility, and dimensional stability have not been thoroughly investigated with the different 3D printers and materials used for their fabrication.

PURPOSE

The purpose of this in vitro study was to evaluate the accuracy, reproducibility, and dimensional stability of additively manufactured surgical templates fabricated by using different 3D printers.

MATERIAL AND METHODS

Thirty surgical templates were designed and additively manufactured from 3 different 3D printers as follows: group SLA (n=10) was fabricated by using a desktop stereolithography (SLA) 3D printer and photopolymerizing resin; group PolyJet (n=10) was fabricated by using a PolyJet 3D printer and photopolymerizing resins; and group DMP (n=10) was fabricated by using a direct metal printing (DMP) system and Co-Cr metal alloy. All surgical templates were scanned by using a laser scanner within 36 hours of production and digitalized again 1 month later. All scanned files were compared with the corresponding designed files in a surface matching software program. The mean deviation root mean square (RMS, measured in mm, representing accuracy), percentage of measurement data points within 1 standard deviation of mean RMS (in %, representing reproducibility), and dimensional changes were determined and compared.

RESULTS

At the postproduction stage, group PolyJet was most accurate with the lowest RMS value of 0.10 ±0.02 mm and highest reproducibility with 93.07 ±1.54% of measurement data points within 1 standard deviation of mean RMS. After 1-month storage, group PolyJet_(1month) remained the most accurate with the lowest RMS value of 0.14 ±0.03 mm and the highest reproducibility value of 92.46 ±1.50%. For dimensional stability, group SLA versus group SLA_(1month) comparison showed a significant decrease in accuracy (RMS values of 0.20 ±0.08 mm versus 0.25 ±0.08 mm, P<.001) and reproducibility (88.16 ±3.66% versus 86.10 ±4.16%, P=.012). Group PolyJet versus group PolyJet_(1month) comparison only showed significant changes in accuracy (RMS values of 0.10 ±0.02 mm versus 0.14 ±0.03 mm, P=.011). Group DMP versus group DMP_(1month) comparison showed no significant changes in accuracy (RMS values of 0.19 ±0.03 mm versus 0.20 ±0.04 mm, P=.981) or reproducibility (89.77 ±1.61% versus 89.74 ±2.24%, P=1.000).

CONCLUSIONS

Printed resin surgical templates produced by using the PolyJet 3D printer showed higher accuracy and reproducibility than those produced by using the desktop SLA 3D printer and printed Co-Cr surgical templates at both the postproduction stage and after 1-month storage. The level of accuracy and reproducibility in printed Co-Cr surgical templates was not affected by 1-month storage.

Anatomical characteristics of maxillary sinus septa visualized by cone beam computed tomography

Proper implant positioning in the posterior region of the edentulous maxilla commonly requires sinus floor elevation. Maxillary sinus septa increase the risk of membrane perforation during sinus floor elevation. The purpose of this retrospective, cone beam computed tomography (CBCT)-based study was to examine the frequency, number, location, and orientation of antral septa in the maxillary sinus. Further, possible associated factors were assessed. Measurements were performed on CBCT scans of 301 patients (602 sinuses). The data were analysed statistically with respect to patient age, sex, and dentition type. One or more septa were detected in 117 patients (38.9%). A total of 188 septa were found in the 602 sinuses (31.2%). Septa were most often coronally oriented (53.2%), followed by sagittal (24.5%) and transverse (22.3%) orientations. Septa were most often found in the region of the first and second molar (37.2%), followed by the posterior region of the third molar (33.0%) and the anterior region of the premolars and canines (29.8%). A significant association was found between edentulism and the presence of septa. For edentulous patients, the septa were most often transversally oriented. Maxillary sinus septa are encountered in every third patient. This may have an influence on the performance of sinus floor elevation.

Evaluation of accuracy and sensory outcomes of mandibular reconstruction using computer-assisted surgical simulation

PURPOSE

To introduce a modified protocol for mandibular reconstruction and evaluate the protocol using a standardized assessment method.

METHOD

This retrospective study involved a case series of nine patients who underwent mandibular reconstruction between 2015 and 2017. The modular protocol comprised three novel modifications in terms of computer-assisted surgical simulation (CASS); surgical template (ST), and surgical procedure. The standardized postoperative evaluation consisted of operation time, part comparison analysis (PCA), facial symmetry, and mechanical quantitative sensory testing.

RESULTS

The surgery successfully removed the affected mandible and preserved the inferior alveolar neurovascular bundle (IANB). PCA revealed that the mean error and standard deviation were 0.92 and 0.96 mm, respectively, for all mandibular surface sites. Follow-up results showed good facial symmetry, existence of sensation in lower lip, and no significant differences in pulp vitality between both sides (p = 0.181). Also, the results showed a reduction in the overall operating time.

CONCLUSION

The modified mandibular reconstruction method used in this study could repair lateral mandibular defects and preserve the sensory function of the chin and lower lip.

Optimizing accuracy in computer-guided implant surgery with a superimposition-anchor microscrew system: A clinical report

The accuracy of computer-guided implant placement decreases when the remaining teeth are poorly distributed. This clinical report demonstrates a protocol for using a superimposition-anchor microscrew (SAM) system to improve the accuracy of computer-guided implant surgery in a posterior unilateral edentulous area. The SAM functioned as a fiducial marker for image superimposition and as an anchor for guide positioning. Applying the SAM system to computer-guided implant surgery enhances the accuracy of implant placement by minimizing possible errors occurring during image registration and guide positioning.

Advanced dental implant placement techniques

The availability of in office Cone Beam CT (CBCT) scanners, dental implant planning software, CAD CAM milling, and rapid printing technologies allow for the precise placement of dental implants and immediate prosthetic temporization. These technologies allow for flapless implant placement, or open flap bone reduction for "All on 4" techniques with improved preoperative planning and intraoperative performance. CBCT permits practitioners in an office setting with powerful diagnostic capabilities for the evaluation of bone quality and quantity, as well as dental and osseous pathology essential for better informed dental implant treatment. CBCT provides the convenience of in office imaging and decreased radiation exposure. Rapid printing technologies provide decreased time and high accuracy for bone model and surgical guide fabrication.

Reconstruction of Mandible: A Fully Digital Workflow From Visualized Iliac Bone Grafting to Implant Restoration

PURPOSE

Although digital aids can help surgeons compensate for the shortcomings of traditional mandibular reconstruction techniques to perform surgery more precisely and effectively, the use of these digital techniques has often been fragmented, divided, and incomplete. This article describes the workflow of a fully digital mandibular reconstruction to explore the proper indications and discusses innovations based on the accuracy and effectiveness of digital techniques.

MATERIALS AND METHODS

A restoration-oriented mandibular reconstruction was performed by applying different digital techniques. Preoperative virtual surgery and rapid prototyping were used to aid the vascularized iliac bone graft surgery, which offered a solid basis for the ensuing treatment. Subsequently, implant rehabilitation was accomplished with the assistance of computer-assisted design and manufacture, laser treatment, and selective laser melting techniques.

RESULT

The workflow of the fully digital mandibular reconstruction successfully achieved a restoration-oriented treatment. These predictable, accurate, and effective digital techniques improved the consistency of pretreatment design and follow-up treatment. The treatment sequence achieved high predictability and reproducibility owing to the use of digital techniques.

CONCLUSION

This study shows that a digital workflow can be predictable, accurate, and effective, which suggests that it could be a valid digital protocol for developing a treatment sequence for patients with jaw defects caused by trauma, congenital anomalies, or mandibular tumor resection.

In-office fabrication of dental implant surgical guides using desktop stereolithographic printing and implant treatment planning software: A clinical report

Guided surgery is accepted as the most accurate way to place an implant and predictably relate the implant to its definitive prosthesis, although few clinicians use it. However, recent developments in high-quality desktop 3-dimensional stereolithographic printers have led to the in-office fabrication of stereolithographic surgical guides at reduced cost. This clinical report demonstrates a protocol for using a cost-effective, in-office rapid prototyping technique to fabricate a surgical guide for dental implant placement.