Students' perception of 3D video microscope use in preclinical fixed prosthodontics: A comparative study.

OBJECTIVES: The purpose of this study was to determine how students perceived the use of a 3D video microscope (3D VM), in comparison to conventional methods, for providing instruction on fixed prosthodontics procedures and issuing feedback on student performance. METHODS: From May until December of 2020, University at Buffalo School of Dental Medicine's second-year students were introduced to fixed prosthodontics. During May and June, a 3D VM was used to live-stream psychomotor skill demonstrations via a web-based software. After each procedure, students were asked to complete a short survey regarding their experience with the training. From August until December 2020, students received feedback via: 1. The conventional method, in which faculty use magnification loupes to assess student's perfromance. 2. A 3D VM. Irrespective of the method used, feedback was given following the same defined rubrics. At the conclusion of the semester, students completed a survey comparing their experiences in receiving instruction and feedback. The data were gathered and analyzed descriptively. The chi-square test (α = .05) was used to gauge if students' gender had an impact on their perception of feedback methods. RESULTS: More than 94% of students participated in the surveys. The majority of students had a positive reaction toward the use of the 3D VM for live web-based training. In regard to receiving feedback, 63% opined that the 3D VM was more effective than the conventional method. Additionally, 80% of students felt that the 3D VM was effective in maintaining physical distance during skill evaluations. CONCLUSION: This study examined the use of a 3D VM for teaching psychomotor skills and providing student feedback and compared it to the conventional method. It was found that the use of the 3D VM was perceived positively by students. Gender had no significant impact on students' attitudes toward the teaching and feedback methods.

Assessment of Teeth Prepared by Senior Dental Students for CAD/CAM Restorations.

The aim of this study was to evaluate teeth prepared for computer-aided design/computer-aided manufacturing (CAD/CAM) restorations by senior dental students using recently developed rubrics. The rubrics used evaluation criteria based on four factors: retention or resistance form; marginal or internal adaption or manufacturing process; biology, esthetics, or durability of restorative material; and intraoral scanner impression. In academic year 2018-19, four faculty members used the rubrics to assess 111 first maxillary right premolars (tooth no. 4) prepared for lithium disilicate crowns and 223 second maxillary right premolars (tooth no. 5) and first maxillary right molars (tooth no. 3) prepared for monolithic zirconia partial fixed dental prostheses. The preparations had been performed on typodont teeth. The most common errors identified for tooth preparations were in the finish line quality (136 errors in 223 prostheses), a criterion that is crucial for quality CAD/CAM restorations. To prevent poorly fit CAD/CAM restoration preparations that result from an unacceptable finish line quality, students need to understand the rationale used to develop detailed rubrics and adhere to the defined critera.

Acquisition of Skills in Operative Dentistry Following a Contemporary Technique Skills Course: A Retrospective Study.

The aim of this study was to evaluate the impact of a contemporary preclinical technique skills course on early dental student performance in a preclinical operative course. Ivorine teeth prepared for Class I resin restorations by the Classes of 2020 and 2021 in one U.S. dental school were evaluated in this study (N=184). Ivorine teeth were prepared during the first practical exam of the operative dentistry course. Students in the Class of 2021 had been enrolled in a contemporary technique skills course a semester prior to the operative dentistry course, while students in the Class of 2020 were not. The preparations were randomly evaluated by three calibrated and blinded faculty members using magnification loupes, an explorer, and a periodontal probe to evaluate external outline form, internal form, depth, and margin following an established rubric. The results showed that students in the Class of 2021 (who had taken the technique skills course) performed significantly better than students in the Class of 2020 for all criteria evaluated (p<0.05). In this study, incorporation of the preclinical technique skills course improved student performance in the subsequent operative dentistry course.

Agreement Between Faculty and %Comparison for Preparation Depth Assessment in a Dental Technique Skills Course.

The aim of this retrospective study was to assess agreement between faculty and virtual assessment software in depth evaluation of rounded rectangular preparations in non-anatomical teeth prepared by second-year dental students. A total of 184 non-anatomical ivorine mandibular first molars prepared by second-year students were retrospectively evaluated in 2018. Each tooth was prepared to a depth of 1.5 mm within a laser-marked outline using a 330 bur, as detailed in the technique skills course syllabus. Preparations were recorded using an intraoral scanner. Then, virtual assessment software was used to superimpose a three-dimensional (3D) image of each preparation on a 3D image of a standard preparation produced by a faculty member. The software was used to calculate percentage comparison (%Comparison) values at 200 µm tolerance. Values of %Comparison ≥72% were considered satisfactory. In addition, each preparation depth was evaluated by two calibrated faculty members using a periodontal probe and a 330 bur. The preparation depth was considered satisfactory when more than 50% of the tooth preparation had a depth of 1.5 mm. The results showed almost perfect agreement (0.81 < kappa < 0.99) between faculty assessment and %Comparison value. The findings suggest that %Comparison values may be used to assess the tooth preparation depth of rounded rectangular preparations in non-anatomical teeth when prepared in a laser-marked outline.

Use of Virtual Comparison Software for Preparation Depth Assessment in a Dental Technique Skills Course.

The aims of this study were 1) to determine whether the Compare software Comparison% score provided appropriate feedback for preparation depth on a non-anatomical tooth and 2) to define an acceptable tolerance for use in calculating the Comparison% for virtual assessment of cavity depth on a non-anatomical mandibular first molar. Forty-six non-anatomical ivorine teeth with laser-marked outlines on their occlusal surfaces were used for this study. One tooth was prepared at a 1.5 mm depth, approved by participating faculty at a U.S. dental school, and served as the standard preparation. The remaining teeth were divided into three groups (n=15 per group) for cavity preparation depths of 1 mm, 1.5 mm, and 2 mm in the laser-engraved external outline. Teeth were prepared using an electric handpiece with a 330 bur and a hatchet. Virtual images of the standard and experimental tooth preparations were recorded using an intraoral scanner. Virtual comparison software was then used to superimpose a three-dimensional (3D) image of each experimental preparation on the 3D image of the standard preparation. The software calculated comparison surface percentage values (Comparison%) at a 100 and 200 micron tolerance for each specimen. Two-way mixed linear models (α=0.01) were adopted to compare outcomes for the two levels of tolerance for teeth with different depths of preparation. Using a tolerance level of 200 µm, Comparison% scores for the acceptable preparation depth of 1.5 mm were found to be significantly different (p<0.01) from those of the unacceptable 1 mm and 2 mm depth preparations. These findings suggest that virtual comparison software may be used to assess an acceptable depth for cavity preparation within a defined external outline.