International Journal of Computerized Dentistry, 04/2024

Aim: The present randomized controlled clinical trial focused on graft volume alterations after sinus floor augmentation with a deproteinized bovine bone mineral (DBBM; Bio-Oss), a deproteinized porcine bone mineral (DPBM; THE Graft), or a biphasic calcium phosphate (BCP; Osopia) material. Materials and methods: A total of 28 patients with edentulism in the posterior maxilla with ≤ 5 mm of residual bone height received a two-staged external sinus grafting procedure with DBBM, DPBM, or BCP. Three CBCT scans were performed: 1) prior to surgery (CBCT1); 2) directly after surgery (CBCT2); 3) after a healing period of 4 to 6 months, prior to implant placement (CBCT3). The CBCT scans were used to analyze volumetric alterations of the sinus grafts by virtual 3D model matching of CBCT1 and CBCT2 (situation after sinus grafting), and CBCT1 and CBCT3 (situation prior to implant placement). Results: The volume of the bone graft in the maxillary sinus (volume [VOL%] directly after grafting rated as 100%) was stable after the healing period in the DBBM (VOL%: 103 ± 4%) and the DPBM (VOL%: 112 ± 23%) groups, with no statistically significant differences regarding 3D measurements. In the BCP group, the grafted volume declined to VOL%: 66 ± 25%, statistically inferior to the DBBM and DPBM groups. Conclusions: Regarding bone graft stability/volume, the DBBM and DPBM groups showed comparable outcomes. Due to resorption, the BCP group showed inferior bone graft volume after healing (statistically significant) compared with the DBBM and DPBM groups. Keywords: 3D, bone substitute, CBCT, sinus grafting, volumetric stability

Aim: Virtual reality (VR) technologies can be used as a content-delivery system for the purposes of both entertainment and education. Remote and digital education has become increasingly important in a world where disruptive events such as global pandemics and natural disasters can define access to face-to-face learning environments. An important aspect of VR technologies for dentistry is the creation of digital 3D models. The primary objective of the present review was to answer the focused research question: “What software techniques are used in the creation of digital 3D models for use in dental education?” Methods: The study systematically evaluated current software and techniques used for creating digital 3D models in dental education using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Results: The search strategies did not find any specific studies relating to the creation of dental-related 3D models. Therefore, this is the first study to provide an overview of common techniques of 3D model fabrication. In addition, some examples of methods of creating 3D models relevant to dentistry such as armamentarium and anatomical oral structures are discussed in considerable detail. Conclusion: The creation of 3D modeling is a rapidly evolving field, with software updates and new programs being continually released. The present study highlights the fundamental lack of published work in the creation of 3D dental models for educational applications. Keywords: 3D modeling, dental education, dentistry, digital modeling, polygonal modeling, virtual reality

Aim: The objective of the present study was to evaluate the failure rate of palatal computer-guided miniscrews placed in the paramedian (PM) and parapalatal (PP) regions for orthodontic purposes. An additional aim was to investigate whether a learning curve was required to perform computer-guided miniscrew insertion as well as to evaluate the peri-implant soft tissue response at three follow-up time points. Materials and methods: A total of 202 palatal computer-guided miniscrews were inserted in 78 subjects for orthodontic purposes. A surgical guide was designed after planning the appropriate insertion sites on 3D images created by the fusion of CBCT scans and digital dental model images. The orthodontic appliances were disassembled monthly to perform a percussion test and evaluate the mobility of each miniscrew. To determine whether a learning curve was required for computer-guided miniscrew insertion, the time point of miniscrew failures and the number of surgeries were evaluated. Bleeding on probing (BOP) and probing pocket depth (PPD) were recorded for each miniscrew at 2- (T0), 6- (T1), and 12-month (T2) follow-up time points. Results: An immediate failure rate of 4.95% was recorded due to lack of primary stability immediately following miniscrew insertion, with a statistically significantly higher failure rate of PP miniscrews (P = 0.00). Failure of the miniscrews occurred at random times, with no learning curve required for their insertion. The measured BOP rates (mean: 3.13%) and PPD values (mean: 1.68 mm) remained stable over time. Conclusions: Computer-guided miniscrew insertion in the palatal vault showed a low failure rate without a determined learning curve required for their insertion to obtain predictable results and with long-term stability of peri-implant soft tissue indices. Keywords: computer-guided surgery, failure rate, orthodontics, skeletal anchorage, TADs

Aim: To evaluate and compare the marginal adaptation and fracture resistance of resin matrix ceramic crowns fabricated using 3D printing and CAD/CAM milling technology. Materials and methods: Thirty extracted human maxillary first premolars were prepared to receive crown restorations and grouped into three groups according to different crown materials used (n = 10): 1) VE: teeth restored with CAD/CAM-milled Vita Enamic; 2) CS: teeth restored with CAD/CAM-milled Cerasmart 270; VSC: teeth restored with 3D-printed VarseoSmile Crown plus. Marginal analysis was performed with the aid of a digital microscope at 230x magnification both before and after cementation with self-adhesive resin cement, and analyzed with ImageJ analysis software. The fracture loads for each sample were then recorded using a universal testing machine in a single load-to-failure test up until crown failure. Results: The lowest marginal gap values were recorded for VSC before (8.03 μm) and after (15.07 μm) cementation, with a significant difference compared with the other crown materials (P 0.05), while the differences between the CAD/CAM-milled groups were not significant, both before (CS [11.35 μm] and VE [11.86 μm]) and after (CS [20.01 μm] and VE [21.08 μm]) cementation. In terms of fracture resistance, the crowns fabricated from VE recorded significantly lower fracture load values (727.8 N; P 0.05) than those fabricated from CS (1213.8 N) and VSC (1181.5 N), which showed no statistically significant differences from each other. Conclusion: 3D-printed definitive crowns outperformed CAD/CAM-milled crowns in terms of marginal adaptation and showed comparable fracture resistance values. Keywords: 3D printing, additive manufacturing, CAD/CAM, milling, resin matrix ceramics

Aim: The purpose of the present systematic review and meta-analysis was to evaluate the marginal adaptation of single-unit full-coverage lithium disilicate fixed dental restorations fabricated with the conventional heat-pressed technique and the digital CAD/CAM workflow. Materials and methods: The present study was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Α study research was conducted in Medline via PubMed and Cochrane Library databases together with a hand search of studies published until June 2022. The search terms combined suitable MeSH (Medical Subject Headings) terms together with free text words in single or multiple conjunctions. A modified methodological index was used to assess the risk of bias of the included studies. A random effects model was applied to pool the effect estimates, and further assessment of the heterogeneity across studies was conducted using the Q test and the I2 metric. All statistical analyses were performed with RStudio software, version 4.1.2, using the “meta” package. Results: The electronic search and hand search identified 51 articles. Eighteen articles met the inclusion criteria and were included in the systematic review, 17 of which were in vitro studies and only 1 was an in vivo study. However, only 17 of the initial 18 articles could be included in the meta-analysis due to a lack of statistical data in one of the in vitro studies. Statistical analyses were conducted using the RStudio software program. Meta-analysis was performed with the random effects model (α = 0.05). No statistical difference was found between the two fabrication methods (P = 0.49). Conclusions: Although the mean marginal adaptation of lithium disilicate single crowns was found to be better with the heat-pressed technique, there was no statistical significance with the CAD/CAM-fabricated restorations, and both resulted in a clinically acceptable result. Nonetheless, more clinical studies are needed for safer conclusions. Keywords: all-ceramic restoration, CAD/CAM, dental ceramics, glass-ceramics, lithium disilicate crown, marginal fit, single crown

Aim: The adjustment and transfer of a stable occlusion can be a major challenge in prosthetic rehabilitations. The aim of the present study was to assess a noninvasive treatment option for complex prosthetic rehabilitations and occlusal analyses using 3D-printed restorations clinically. Materials and methods: Eleven patients received a partial or complete rehabilitation with the aid of 3D-printed restorations (n = 171). After 12 months of clinical service, all restorations were analyzed using the United States Public Health Service (USPHS) criteria. Results: The 12-month clinical data revealed that 3D-printed restorations showed a survival rate of 84.4%. Complications occurred mostly regarding the anatomical form (7%) or marginal integrity (6%) and were consequently rated “Charlie” or “Delta.” Color stability and color match of 3D-printed restorations were rated “Alpha” in 83% and 73%, respectively, of all restorations. Marginal inflammation was rated “Alpha” in 89% of all restorations. An excellent surface texture and no secondary caries or postoperative sensitivities (100%) were observed. Conclusions: 3D-printed restorations might be an alternative treatment option for initiating complex prosthetic rehabilitations. Technical complications rarely occurred. Biologic complications did not occur at all. The color stability showed promising results after 12 months of clinical service. However, the results should be interpreted with caution until long-term results with a high number of restorations are available. Keywords: 3D-printing, additive manufacturing, color stability, wear behavior, in vivo, CAD/CAM

Aim: Learning tooth preparation techniques and the finesse required is an important part of preclinical dental education. Being able to practice surgical skills without loss of Frasaco teeth while being provided with performance analysis data is a boon to students and educators. The present authors investigated the combination of haptics-enhanced virtual reality (Simodont) and conventional phantom head practice in a preclinical dental course, evaluating the students’ performances and perceptions. Materials and methods: Forty students were randomized into two groups: Group One worked within a VR-haptic setting, while Group Two worked with Frasaco teeth. Halfway through the course, the scenarios were switched. A crown preparation test on the Frasaco teeth was conducted at the end of the course. Students’ performances and satisfaction were assessed anonymously. Analysis of the students’ performances included clinical metrics (occlusal and axial reduction, convergence angle, damage to adjacent teeth). The perceived usefulness of VR-haptic and phantom head simulations was assessed. Results: In Group One, the tooth preparation metrics were more in line with the requested parameters compared with Group Two. All students ranked VR-haptics highly with regard to manual dexterity improvement. Conclusion: The present study shows that by combining VR-haptics with conventional dental procedures it is possible to improve important preparation metrics in fixed prosthodontics tooth preparation. Keywords: dental training, manual dexterity, practice-based learning and improvement, VR-haptic simulation

Aim: The objective of the present study was to investigate the clinical understanding and reasoning abilities of large language models (LLMs); namely, ChatGPT, GPT-4, and New Bing, by evaluating their performance in the NDLE (National Dental Licensing Examination) in China. Materials and methods: Questions from the NDLE from 2020 to 2022 were selected based on subject weightings. Standardized prompts were utilized to regulate the output of LLMs for acquiring more precise answers. The performance of each model across each subject category and for the subjects overall was analyzed employing the McNemar’s test. Results: The percentage scores obtained by ChatGPT, GPT-4, and New Bing were 42.6% (138/324), 63.0% (204/324), and 72.5% (235/324), respectively. Significant variance was seen between the performance of New Bing compared with ChatGPT and GPT-4. GPT-4 and New Bing outperformed ChatGPT across all subjects, with New Bing surpassing GPT-4 in most subjects. Conclusion: GPT-4 and New Bing exhibited promising capabilities in the NDLE. However, their performance in specific subjects such as prosthodontics and oral and maxillofacial surgery requires improvement. This performance gap can be attributed to limited dental training data and the inherent complexity of these subjects. Keywords: artificial intelligence, big data, evidence-based dental/health care, dental education, deep learning/machine learning