Haptics in fixed prosthodontics and their role in dental education: A literature review.

Technological progress leads to new advances in dental education. One of the applications involves the use of virtual and augmented reality as educational aids. The emerging question is to establish if and how these enhancements may prove beneficial to the overall student learning process. A review of recent literature was conducted with the aim of providing evidence for the development of relevant clinical guidelines. The proposed topic attempted to provide answers to the questions of (a) how participants perform when using haptic devices compared to traditional tooth preparation methods on typodonts, (b) how the use of simulators is perceived by both students and educators, and (c) what added value simulators may have in prosthetic dentistry training. The main findings of this study showed that participants expressed satisfaction with the educational experience, finding it both stimulating and very similar to the actual clinical environment. However, differences between haptic and conventional methods were also apparent. Haptics was a significant predictor of clinical crown performance. Significantly better results and shorter preparation times tended to increase with experience. In conclusion, self-directed learning appears to be beneficial in the clinical education that follows data-driven approach. At the pre-laboratory level, simulators may act as an initial familiarization instrument. At the preclinical level, they may aid in detecting students who require extra assistance, or to provide extra training hours for students lacking adequate competency to enter the clinical training phase.

Haptics Vs Typodonts for Crown Preparation in Undergraduate Dental Student Education.

OBJECTIVES: This study aims to compare students' subjective perceptions and objective results by comparing two methods of crown preparation: typodonts and haptics. MATERIALS AND METHODS: Fifty-four second-year students were given instructions on crown preparation for the upper right second premolar. First on typodonts and then with haptics. They were given five minutes to familiarize with the artificial environment and then thirty minutes for the actual preparation. Finally, they completed a questionnaire about their experience. Their preparations were objectively compared by measuring the angle of total occlusal convergence-TOC on the typodonts and with haptics. RESULTS: Students reported that haptics can enhance the learning process and that they would use them for skill training in the future. Overall, their experience was rated as positive. The TOC of teeth prepared with haptics was significantly higher than those prepared with typodonts, but all values were within the acceptable range. CONCLUSION: Although students did not prefer haptics to typodonts, haptics appear to be a powerful tool in the educational process because it can be a complementary option to traditional methods at the preclinical level.

Application of digital scanning combined with reverse engineering technology in the teaching of full crown preparation / 中华医学教育探索杂志

Objective:To investigate the application of digital scanning combined with reverse engineering technology in the teaching of full crown preparation.Methods:A total of 30 undergraduate students in the fifth grade of stomatology were selected from Shantou University Medical College and were divided into experimental group and control group using a random number table. Two resin teeth were distributed to each student and were placed on dental head simulators to perform full crown preparation. The students in the control group received teaching with analogies of experience, and those in the experimental group received teaching with digital scanning, i.e., full crown preparation for the second time after digital scanning for the first time of full crown preparation. The score was determined based on China Stomatological Association Standards: Guideline for the tooth preparation of dental ceramic crowns (T/CHSA 008—2023), with a total score of 100 points. SAS9.4 software was used for the two-independent-samples t test and the paired t-test, and the Kendall W concordance coefficient was used to investigate the consistency of evaluators. Results:There were significant changes after teaching in the preparation scores of the right maxillary central incisor (76.27 pre-demonstration vs. 84.70 post-demonstration, P<0.001) and the right maxillary first molar (72.10 pre-demonstration vs. 82.37 post-demonstration, P<0.001). Compared with the control group, the experimental group had a significant increase in the mean preparation score of the right maxillary first molar (14.00 vs. 6.53, t=2.64, P=0.014). In the experimental group, there were significant increases in the preparation scores of the right maxillary first molar for the occlusal surface (15.40 pre-demonstration vs. 19.33 post-demonstration, P<0.001), the buccolingual surface (18.13 pre-demonstration vs. 20.87 post-demonstration, P=0.016), and the proximal surface (12.40 pre-demonstration vs. 14.07 post-demonstration, P=0.004), as well as significant increases in the scores of the convergence angles of the buccolingual surface (2.80 pre-demonstration vs. 4.07 post-demonstration, P=0.004) and the proximal surface (3.47 pre-demonstration vs. 4.47 post-demonstration, P=0.008). Conclusions:Application of digital teaching for difficult crown preparation of posterior teeth can effectively improve the quality of crown preparation among students, standardize the teaching process of crown preparation, and increase the precision of crown preparation, thereby laying a foundation for promoting uniformity in talent cultivation for dental prosthodontics.

Crown Preparation in a Patient with Hypertension and Type 2 Diabetes Mellitus.

Management of the diabetic dental patient should focus on the delivery of comprehensive dental care with an emphasis on maintaining periodontal health. Gingivitis, periodontitis, and associated bone loss independent of plaque accumulation are associated with poorly controlled diabetes. Periodontal status should be monitored carefully in patients with diabetes and underlying disease managed aggressively. Likewise, the dental team plays an important role in the identification of hypertension and managing dental-related side effects of anti-hypertensives.

Droplet Distribution in a University Dental Clinic Setting: The Importance of High-Volume Evacuation.

The purpose of this study is to compare droplet distribution during a piezoelectric ultrasonic debridement procedure using either high-volume or slow-volume evacuation. Droplet distribution during a crown preparation with slow-volume evacuation is also examined. Fluorescein dye is added to the water reservoir and the procedures are performed by a single operator for 15 min on a dental manikin with artificial upper and lower teeth. Placement of filter paper squares (10 cm × 10 cm) in radiating lines away from the oral cavity of the dental manikin allows for visualization of droplet dispersion. Results show minimal difference in the spread of the droplets between the two evacuators during the debridement procedure; however, the slow-volume evacuator produces a higher concentration of droplets than the high-volume evacuator. An even higher concentration of droplets in the vicinity of the dental chair is observed during the crown preparation procedure. This study recommends the use of a high-volume evacuator where possible during professional debridement and crown preparation to reduce contamination around the dental chair from potentially pathogenic microorganisms.

Scanning Accuracy of 10 Intraoral Scanners for Single-crown and Three-unit Fixed Denture Preparations: An In Vitro Study.

OBJECTIVE: To evaluate the accuracy of 10 intraoral scanners for single-crown and three-unit preparation models. METHODS: A maxillary partially edentulous model was fabricated. A dental cast scanner was used to obtain standard tessellation language (STL) data. Ten intraoral scanners, namely Trios 2 (TR2; 3Shape, Copenhagen, Denmark), True Definition (TD; 3M, Saint Paul, MN, USA), CEREC AC Omnicam (OM; Dentsply Sirona, Charlotte, NC, USA), Organical Scan Oral (OS; R+K, Berlin, Germany), PlanScan (PS; Planmeca, Helsinki, Finland), DWIOP (DW; Dental Wings, Montreal, Canada), Xianlin (XL; Hangzhou Xianlin, Hangzhou, China), DL-100 (DL; Guangzhou Longcheng, Guangzhou, China), Trios 3 (TR3; 3Shape) and i500 (MD; MEDIT, Seoul, South Korea) were used to obtain stereolithography data as test groups. Trueness, precision and surface accuracy were evaluated by deviation analysis using 3D image processing software. One tooth with a three-unit preparation for each test group was registered with the reference scan data, and the absolute distance from another tooth was calculated as the absolute accuracy. The data were analysed using a Mann-Whitney U test and Dunn-Bonferroni test (α = 0.05). RESULTS: The best trueness, precision and surface accuracy of scanning single crown preparation were recorded with TD (trueness 2.9 µm and precision 1.9 µm) and XL (surface accuracy 20.3 ± 2.9 µm). The best trueness, precision, surface accuracy and absolute accuracy of three-unit preparations were recorded with TD (2.6 µm), XL (1.9 µm), OM (27.1 ± 5.2 µm) and TR3 (79.2 ± 19.6 µm), respectively. There was no statistically significant difference in trueness between single- and multiple-unit preparations for any of the intraoral scanners (P > 0.05). A statistically significant difference in the surface accuracy between single and multiple preparations was found for TR2, TD, OM, DW, XL, DL and MD (P < 0.05). CONCLUSION: The trueness and precision of intraoral scanners for scanning three-unit preparations were nearly the same as those for single-crown preparations; however, with the exception of OS, PS and TR3, the surface accuracy of single-crown preparations was significantly better than that for three-unit preparations.

Clinical assessment of resin-coating technique applied to exposed dentin after crown preparation.

The resin-coating technique, in which exposed dentin surfaces are covered using a thin-film coating material, was approved in the Japanese public health insurance system in December 2019. The purpose of this study was to evaluate clinical cases treated using the resin-coating technique with Hybrid Coat II (HC II) after tooth preparation on vital teeth. A total of 134 cases from patients who visited nine dental clinics were examined from the clinical records. Clinical signs and symptoms of cases before, during, and after treatment and at the time of recall were evaluated. The resin-coating was applied as either a single application with HC II (86.6%) or a combined application of HC II and a flowable resin composite (13.4%). The success rate without any symptoms of sensivity to cold water was 92.5% (124 cases). The current results indicated that the resin-coating with HC II is a reliable treatment for the tooth preparation of vital teeth.

Investigation on the quality analysis of 1 312 single crown digital models.

OBJECTIVES: This study aimed to investigate the quality of single crown digital models, enhance communication between clinicians and technicians, and improve the quality of restorations to further reduce remake rate. METHODS: A total of 1 312 single crown digital models (180 anterior teeth, 294 premolars, and 838 molars) were randomly selected from a large commercial dental factory. The digital models were evaluated by three investigators with the same working experience with the same intraoral scanning system (CEREC). CEREC SW 4.4 was used in capturing the images of single crown preparations, and prepCheck 3.1 was used in evaluating the quality of single crown digital models. RESULTS: Approximately 6.55%, 0.08%, 81.17%, 19.59%, and 22.48% of 1 312 single crown digital models did not meet the standards of the undercut, surface quality, margin quality, buccal-lingual taper, and mesiodistal taper, respectively. Moreover, 23.25%, 28.51%, 28.43%, and 28.35% of the investigated single crown digital models did not meet the standards of the buccal inclination taper, lingual inclination taper, mesial inclination taper, and distal inclination taper, respectively. The quality of anterior teeth, premolars, molars at the margin quality, buccal-lingual taper, mesiodistal taper, buccal inclination taper, lingual inclination taper, mesial inclination taper, and distal inclination taper significantly varied in the evaluation results (P<0.01). CONCLUSIONS: In addition to the undercut and surface quality met the standard, the overall situation of the quality of the single crown digital preparation model was poor, and the quality of the preparation needs to be improved urgently.

Fit of tooth-supported zirconia single crowns-A systematic review of the literature.

PURPOSE: The purpose of this study is to systematically map all the factors that influence the fit and adaptation of zirconia crowns and/or copings. MATERIALS AND METHODS: The investigational strategy involved carrying out an electronic search between December 1, 2009 and September 1, 2019 through the Embase and Medline databases using Boolean operators to locate appropriate articles. RESULTS: A total of 637 articles were discovered after the removal of duplicates, and 46 of these were selected for evaluation. Further, a quality assessment was performed using GRADE evaluation criteria. CONCLUSIONS: Shoulder finish line preparations had slightly better marginal fit compared to chamfer finish lines. Crowns obtained from digital impressions had comparable to superior marginal adaptation compared to conventional impressions. Increasing cement space showed to improve zirconia crown adaptation. Cementation and veneering zirconia frameworks found to increase the marginal and internal gaps. Limited information is available on the effect of the alteration of sintering time/Temperature and/or sintering techniques on the adaptation of zirconia crowns. Most of the selected studies had a moderate quality assessment evaluation. Future studies could investigate the chair-side, ultra-fast sintering effect on the marginal gap of zirconia crowns.

Effect of a Standardized Training with Digital Evaluation on the Improvement of Prosthodontic Faculty's Performance in Crown Preparation: A Pre-Post Design.

PURPOSE: Standardized crown preparation is an important competency for prosthodontic faculty especially when they take on the dual role of clinician and clinical teacher. Effects of faculty training for enhancing crown preparation competency are seldom reported. This study aimed to analyze the impact of a standardized training workshop with digital evaluation on the dental faculty's performance in crown preparation. MATERIALS AND METHODS: The digitally evaluated grades of anterior (the maxillary right central incisor) and posterior (the mandibular left first molar) tooth preparations made by 76 participants who accomplished all six training tasks were collected, including off-site and on-site exercises before the didactic lecture and live demonstration, three rounds of practices with digital feedback, and a final test. Grades of preparations performed in the on-site exercise were adopted as pre-training scores, and those in the final test as post-training scores. Total scores and marks deducted for the parameters including amount of reduction, margin line, and taper were compared among each training task. RESULTS: The post-training scores of both anterior and posterior tooth preparations increased significantly more than the pre-training scores. The average increased score proportion was 22.95% ± 4.17% for anterior tooth preparations, and 21.78% ± 3.68% for posterior tooth preparations. For anterior tooth preparations, total scores and the parameters except taper significantly improved in the first practice and maintained the same level for the next sessions. Total scores and all parameters for posterior tooth preparations exhibited continual improvement during the training process. CONCLUSION: Standardized training can further improve dental faculty's crown preparation performance in a moderate way. Individual design for crown preparation training can be considered based on different tooth positions. Providing such training will aid the calibration of clinical teaching behavior and the elevation of clinical operative standards for prosthodontic faculty.

Investigation of inter- and intra-rater reliability using digital dental software for prosthodontics crown preparations.

INTRODUCTION: Since the introduction of the digital dental assessment systems, there has been a shift towards this trend as it appears to provide a more accurate, reliable, time efficient, and reproducible assessment. The Planmeca Emerald scanner coupled with Romexis Compare software allows students and staff to objectively assess individual crown preparations, receive numerical values of key dimensions, and subsequently undergo comparison with ideal crown preparation dimensions. OBJECTIVES: To measure the inter- and intra-rater reliability using the intra-oral scanner and Romexis Compare for prosthodontic crown preparations, and to evaluate the possible implementation of this software as a grading and self-assessment tool in a preclinical setting. METHODS: The Planmeca scanner and Romexis Compare were used to compare the difference between 30 experimental preparations (n = 15 anterior teeth, n = 15 posterior teeth) with their respective unprepared typodont teeth. Three student examiners (W., K., V.) independently scanned the typodont teeth in pre-formed standardized and non-standardized putty jigs. Each preparation was measured from facial, lingual, incisal/occlusal, and margin surfaces. A second trial was completed after 2 weeks to assess intra-rater reliability. The data were tabulated, graphed, and analyzed using SPSS and GraphPad Prism. RESULTS: The results of the study show greater consistencies in inter-operator measurements for anterior teeth. Some variations, however, were found in posterior teeth measurements between the operators. The results of the intra-rater measurements appear to be relatively consistent. CONCLUSION: With some limitations, Romexis Compare can be used as a reliable and repeatable method for objective and consistent evaluation of student prosthodontic preparations in a preclinical setting.

Simulation training for ceramic crown preparation in the dental setting using a virtual educational system.

OBJECTIVES: The aim was to evaluate the effectiveness of a pre-clinical training of ceramic crown preparation using the Virtual Educational System for Dentistry. MATERIAL AND METHODS: Fifty-seven dental students were recruited to prepare a ceramic crown under the guidance of the Real-time Dental Training and Evaluation System (RDTES) in order to collect pre-learning data. They participated in the online virtual learning course independently on the Virtual Learning Network Platform (VLNP). One week later, the students were invited to complete their post-learning crown preparation with the RDTES. A questionnaire survey explored students' perceived benefits or drawbacks of the virtual educational system. Students were allocated into Group A (n = 15), B (n = 24) and C (n = 18) based on their pre-learning performance. Differences of assessment results amongst different groups were evaluated by ANOVA and Kruskal-Wallis tests. The pre- and post-learning assessment results in all groups were compared using paired t tests or Wilcoxon signed rank tests. RESULTS: The error scores for four assessment items (instrument selection, preparation section, preparation reduction, preparation surface and profile) and total score of outcome assessment after the virtual learning were significantly different with those before the virtual learning (P < 0.05). There were significant interactions between time and student group in the mean scores of process and outcome assessments (P < 0.001), except for the assessment item "damage of adjacent teeth." CONCLUSION: The application of a Virtual Educational System for Dentistry with the VLNP and RDTES in pre-clinical operative training helps students improve their clinical skills.

Retrospective Study of 18 Titanium Alloy Crowns Produced by Computer-Aided Design and Manufacturing in Dogs.

Computer-aided design (CAD) and computer-aided manufacturing (CAM) technology is routinely used in various fields of human dentistry, particularly prosthodontics. Reverse engineering and additive manufacturing allow the technician to create an easier, faster and more accurate restoration, with a natural design and adequate strength. Eighteen titanium alloy full crowns were produced for canine teeth of 7 working dogs using CAD/CAM technology (3D BioCare, Nobel Biocare). Reasons for crown therapy included abrasion, enamel infraction, and crown fracture. Crown preparation was routinely performed, and impressions were delivered to the laboratory where digital impressions were performed with a lab scanner. Using 3D dental design software, the metal crown was designed and sent for manufacture. Each prosthodontic crown was then carved from a solid titanium alloy block to obtain the final crown. All prosthodontic crowns were an adequate fit, and cementation was routinely performed. Crowns were lost from 2 canine teeth during the dogs' normal working activity, in one case, for 2 times. In all cases, replicas were requested. In the first case, the second cementation was successful. In the second case, the second crown was again lost and only the third cementation was successful. Follow up of all cases range from 12 to 62 months. Mean survival time for the crowns was 58.0 months. Here, CAD/CAM technology is shown to be a useful tool for manufacturing accurate prosthodontic crowns for veterinary patients. Moreover, CAD/CAM enables the production of prosthodontic crown replicas in a very short time and at relatively low cost compared to traditional methods, consequently eliminating the need for at least one anesthetic procedure in the incidence of crown cementation failure.

Rubric system for evaluation of crown preparation performed by dental students.

OBJECTIVE: This study aimed to investigate the use of an analytic rubric system for the evaluation of all-ceramic crown preparation on the right maxillary central incisor performed by the dental students. MATERIALS AND METHODS: Seventy-two-third-year students and 8 faculty members from prosthodontics participated in this double-blind study. The students prepared an ivorine tooth # 11 for all-ceramic crown. The students were given clear instructions regarding the all-ceramic crown preparation and informed about the criteria for the assessment of the preparation. An analytic rubric based on 10-point scale for assessment of various preparation parameters was used by the 8 examiners. Descriptive statistics, ANOVA and post hoc Tukey tests were used for statistical analysis. RESULTS: One-way analysis of variance indicated significance amongst the examiners for all the parameters except for time management. The overall mean scoring by examiners was 7.60 ± 1.18, with highest and lowest mean scores for Examiner 1 (8.02 ± 1.06) and Examiner 4 (6.82 ± 1.50), respectively. The highest number of interexaminer variation (difference) in scoring was found for two plane reduction, and the least difference amongst the examiners was observed for finishing of margins and walls of the preparation. Examiner 4 had the highest number of significant difference with the rest of the examiners. The students scored least marks in axial reduction (56.33%) and preservation of adjacent teeth (66.9%). CONCLUSIONS: Criteria-based assessment using analytic rubric for crown preparations in pre-clinical fixed prosthodontics is an effective tool for finding the errors/weak areas of dental students.

Limitations of Surface Mapping Technology in Accurately Identifying Critical Errors in Dental Students' Crown Preparations.

The aim of this study was to evaluate the effectiveness of the Planmeca Compare software in identifying and quantifying a common critical error in dental students' crown preparations. In 2014-17, a study was conducted at one U.S. dental school that evaluated an ideal crown prep made by a faculty member on a dentoform to modified preps. Two types of preparation errors were created by the addition of flowable composite to the occlusal surface of identical dies of the preparations to represent the underreduction of the distolingual cusp. The error was divided into two classes: the minor class allowed for 1 mm of occlusal clearance, and the major class allowed for no occlusal clearance. The preparations were then digitally evaluated against the ideal preparation using Planmeca Compare. Percent comparison values were obtained from each trial and averaged together. False positives and false negatives were also identified and used to determine the accuracy of the evaluation. Critical errors that did not involve a substantial change in the surface area of the preparation were inconsistently identified. Within the limitations of this study, the authors concluded that the Compare software was unable to consistently identify common critical errors within an acceptable degree of error.

Utilising an innovative digital software to grade pre-clinical crown preparation exercise.

BACKGROUND: Accurate assessment of dental students' pre-clinical work is the most critical component of the dental education process. Thus, this study came to investigate the effectiveness of using technology in students' pre-clinical work evaluation; by comparing grades generated from a digital assessment software of a prepared tooth and a traditional visual inspection carried out by four calibrated faculty members. METHODS: Ninety-six teeth were prepared for a ceramo-metal crown by fourth year dental students. The four examiners and the digital grading software evaluated independently each preparation once. A random sample of 20 preparations were graded twice to assess intra-rater reliability. Inter-class correlation (ICC) was used to measure agreement among the four examiners, and between the examiners and the digital grading software. Paired student t-test was used to assess the accuracy of grades generated from visual inspection when compared to the digital grading system. RESULTS: Intra-rater reliability for examiners 1 and 2 were 0.73 and 0.78 and for the digital grading system was 0.99. The inter-rater reliability among the four examiners was very good, ICC of 0.76. However, the agreement between scores produced by the examiners and the digital system were mostly in the low to moderate range. The paired t-test demonstrated statistically significant differences between each examiner and the digital grading by 6-25 grades. CONCLUSIONS: This study demonstrates that the digital grading system used in this study can reliably scan and compare students' tooth preparations to a known gold standard. Results of this study suggests that using digital grading will preclude the variability and the subjectivity that usually result from the traditional visual inspection grading.

All-ceramic crown preparations: An alternative technique.

BACKGROUND: The aim of this study was to compare the crown preparation dimensions produced from two different techniques of preparation for posterior all-ceramic crowns. METHODS: Twenty-four fourth year dental students undertook a course of advanced simulation training involving education in an alternative technique of preparation for a 36 all-ceramic crown. Crown preparations performed using the traditional technique were compared with an alternative technique for total occlusal convergence (TOC) and reduction difference (RD) using digital scanning and comparative software. RESULTS: Groups that spent the most time performing the alternative technique produced crown preparations with significantly lower buccolingual (BL) TOC. The training resulted in crown preparations that were closer to ideal TOC and RD measurements. CONCLUSIONS: The alternative technique of crown preparation for a posterior all-ceramic crown showed initial promise in creating a less buccolingually tapered and more ideally occlusally reduced crown preparation.

Quantitative Comparison of Mathematical Models to Measure Surface Area of Canine Teeth Prepared to Receive Full Veneer Crowns in Dogs.

OBJECTIVE: This study was performed in order to determine if mathematical modeling of the canine teeth in dogs could be utilized to provide an accurate and reliable estimation of crown surface area that could be used in both a research and a clinical setting. MATERIALS AND METHODS: Actual surface area (aSA) calculations for 32 stone dies of clinical crown preparations were acquired utilizing a tridimensional (3D) laser scanner and 3D computer-aided design and manufacturing (CAD/CAM) software applications. These calculations were used as a control. Seventeen unique mathematical models from eight geometric shapes were used to calculate estimated surface area (eSA) of each stone die. Linear association and agreement between eSA and aSA calculations were assessed with multiple statistical methods. RESULTS: All methods of eSA showed a significant linear association with aSA. Five of the mathematical models [right elliptical frustum (H3), right elliptical cone (G3), right pyramidal cone (A3), right circular frustum (F2), and right circular cone (E1)] were superior to the other 12 models. CONCLUSION: The H3 mathematical model based on the right elliptical frustum provided the most accurate estimate of crown surface area of dog teeth. However, H3 requires the use of laser scans and a 3D CAD software program. As a result, this model would be recommended for research applications. The E1 mathematical model was similar in accuracy to H3 and, given it requires only two measurements and a comparatively simple equation for calculation, this method would be recommended for clinical chair-side use.

A prospective study of the incidence of asymptomatic pulp necrosis following crown preparation.

AIM: To determine the incidence of asymptomatic pulp necrosis following crown preparation as well as the positive predictive value of the electric pulp testing. METHODOLOGY: A total of 120 teeth with healthy pulps scheduled to receive fixed crowns (experimental teeth) were included. Teeth were divided into two groups according to the preoperative crown condition (intact teeth and teeth with preoperative caries, restorations or crowns) and into four groups according to tooth type (maxillary anterior teeth, maxillary posterior teeth, mandibular anterior teeth and mandibular posterior teeth). Experimental and control teeth were submitted to electric pulp testing on three different occasions before treatment commencement (stage 0), at the impression making session (stage 1) and just before the final cementation of the crown (stage 2). Teeth that were considered to contain necrotic pulps were submitted to root canal treatment. Upon access, absence of bleeding was considered as a confirmation of pulp necrosis. Data were analysed using bivariate (chi-square) and multivariate analysis (logistic regression). All reported probability values (P-values) were based on two-sided tests and compared to a significance level of 5%. RESULTS: The overall incidence of pulp necrosis was 9%. Intact teeth had a significantly lower incidence of pulp necrosis (5%) compared with preoperatively structurally compromised teeth (13%) [(OR: 9.113, P = 0.035)]. No significant differences were found amongst the four groups with regard to tooth type (P = 0.923). The positive predictive value of the electric pulp testing was 1.00. CONCLUSIONS: The incidence of asymptomatic pulp necrosis of teeth following crown preparation is noteworthy. The presence of preoperative caries, restorations or crowns of experimental teeth correlated with a significantly higher incidence of pulp necrosis. Electric pulp testing remains a useful diagnostic instrument for determining the pulp condition.

Effectiveness and feasibility of utilizing E4D technology as a teaching tool in a preclinical dental education environment.

Recent efforts have been directed towards utilizing CAD/CAM technology in the education of future dentists. The purpose of this pilot study was to investigate the feasibility of implementing CAD/CAM technology in instruction on preparing a tooth for restoration. Students at one dental school were assigned access to CAD/CAM technology vs. traditional preparation methods in a randomized, crossover design. In a convenience sample of a second-year class, seventy-six of the seventy-nine students volunteered to participate, for a response rate of 96 percent. Two analyses were performed on this pilot data: a primary effectiveness analysis comparing students' competency exam scores by intervention group (intention-to-treat analysis) and a secondary efficacy analysis comparing competency exam scores among students who reported using CAD/CAM versus those who did not. The effectiveness analysis showed no difference in outcomes by intervention group assignment. While student survey results indicated interest in utilizing the technology, the actual utilization rate was much less than one might anticipate, yielding a sample size that limited statistical power. The secondary analysis demonstrated higher mean competency exam scores for students reporting use of CAD/CAM compared to those who did not use the technology, but these results did not reach statistical significance (p=0.075). Prior research has investigated the efficacy of CAD/CAM in a controlled educational trial, but this study adds to the literature by investigating student use of CAD/CAM in a real-world, self-study fashion. Further studies should investigate ways in which to increase student utilization of CAD/CAM and whether or not increased utilization, with a larger sample size, would yield significant outcomes.