Investigating correlations between the PAT and three hand-skill exercises to performance in preclinical laboratory courses.

OBJECTIVES: Perceptual ability test (PAT) is a valid determinant for spatial perceptions. However, proven psychomotor skill tests for dentistry do not currently exist. This study aimed to determine whether performance on the PAT, Operation game, mirror tracing, and wax carving exercises correlate to preclinical laboratory performance in Dental Anatomy and Restorative Dentistry courses. METHODS: First-year dental students (n = 96) participated in the study. Final laboratory grades were obtained from course directors of preclinical Restorative Dentistry and Dental Anatomy courses. Admissions committee provided participants' PAT results. Participants completed a wax carving exercise by carving a cube and a semicircle into a wax block using the wax subtraction method. Two calibrated faculty graded the carvings as Ideal (5), Satisfactory (3), or Unsatisfactory (1). Time to complete the Operation game and number of infractions were recorded. Participants traced the six-pointed star pattern on the Auto Scoring Mirror Tracer instrument in both clockwise and counterclockwise directions. Completion times and number of instances outside the pattern were recorded. Spearman Rank Correlations were used to determine associations at 0.05 confidence interval. RESULTS: Mean PAT score was 21.7; mean times to complete the Operation game and mirror tracing exercise were 4:20 and 1:30, respectively. Mean score on the wax carving exercise was 3.19. Correlations between the independent and dependent variables were minimal to weak. The wax carving exercise was the most reliable predictor of performance. CONCLUSIONS: When PAT scores are striated into low (less than 20), middle (21-22), and high (23-30), it was possible to predict performance in both preclinical laboratory courses.

An evaluation of factors affecting dental shade matching in first-year dental students.

STATEMENT OF PROBLEM: Shade selection has become more important and challenging as it becomes more emphasized in esthetic dentistry. It would be beneficial to screen dental students early in their predoctoral education for any deficiencies in color discrimination. Specific tests that reliably predict dental shade-matching ability have not been fully established. PURPOSE: The purpose of this study was to determine whether the Farnsworth-Munsell 100 Hue Test (FM-100), Perceptual Ability Test (PAT), ethnicity, age, sex, and time to complete the tests affect dental shade-matching ability and value discernment in first-year dental students. Secondary aims were to determine whether correlations exist between performance on the PAT and FM-100 and between FM-100 and dental shade matching. MATERIAL AND METHODS: The FM-100 test was administered to 98 first-year dental students in a Judge II booth (color temperature=6500 K, color rendering index=90). The Vita Toothguide 3D-Master shade guide was used in this study. For the Value Test, students arranged 3 sets of 5 masked shade tabs from lightest to darkest. In all 3 sets, the value ranged from 1 to 5. In set #1, each shade tab had the same hue and chroma. In set #2, the hues were constant, but the chroma varied. In set #3, the hue and chroma varied. For the Matching Test, students matched together 11 pairs of masked shade tabs from 2 shade guides. Ethnicity (white, African American, Hispanic, Middle Eastern, and Asian), PAT scores, age, sex, and time to complete tests were recorded. Data were analyzed by using least square means, Wilcoxon Rank Sum, Kruskal-Wallis, and Spearman correlation tests (α=.05). RESULTS: FM-100 total error scores (TES) ranged from 0 to 188. Forty-three students had superior color discrimination (TES 0 to16), 51 had average (TES 20 to 100), and 4 had poor color discrimination (TES>100). Ethnicity, age, and sex did not significantly affect performance on any tests. Longer completion time resulted in better performance on FM-100 (P=.002) and Matching Tests (P=.032). However, increased time resulted in fewer correct answers on the Value Test (P=.016). There was a significant effect of PAT on FM-100 results (P<.001). As PAT scores increased, TES scores decreased, indicating better color discrimination. Similarly, lower TES scores resulted in higher Matching Test results (P<.001). However, this was not observed on the Value Test (P=.302). Correlation between the PAT and FM-100 was weak (r=-0.217), as well as between the FM-100 and Matching Test (r=-0.364). CONCLUSIONS: Ethnicity, age, and sex did not affect dental shade-matching ability. Participants with higher PAT scores demonstrated higher color discrimination on the FM-100 and were better at matching dental shade tabs. Time had different effects on the Matching and Value tests.

Wax carving exercises predict performance on practical examinations for first-year dental students.

Perceptual ability test (PAT) is a valid determinant for spatial perceptions. However, a validated psychomotor skill test for dentistry does not currently exist. PURPOSE/OBJECTIVES: This study aimed to determine whether the results of two wax carving exercises (E1 and E2), PAT, quantitative reasoning (QR), and academic average (AA) tests predict students' performance on dental anatomy practical examinations. METHODS: First-year dental students (n = 69) participated in the study. Results of the PAT, QR, and AA were obtained from the Admissions Office. Participants completed wax carving exercises during the first (E1) and last weeks (E2) of the dental anatomy course. Carving instruments, instruction, and rubrics, were provided to participants who were instructed to carve a cube and a semicircle shape into a wax block using the wax subtraction technique. Two calibrated and blinded faculty graded the exercise as ideal, satisfactory, or unsatisfactory in four categories: finish, sharpness, symmetry, and accuracy. During the dental anatomy course, participants completed wax carving practical examinations for a maxillary central incisor and a mandibular first molar. Examinations were graded by calibrated faculty as ideal, satisfactory, or unsatisfactory. The linear mixed effects model assessed influences of independent variables on the practical examinations. RESULTS: estimates of the independent variables on the practical examinations were PAT (0.027), AA (0.088), QR (-0.014), E1 (0.235), and E2 (0.175). CONCLUSIONS: wax carving exercises were stronger predictors of performance on the practical examinations than the PAT, AA, and QR. This simple exercise may help identify students early in their preclinical education requiring additional assistance.

Microshear bond strength of resin luting agents to monolithic zirconia.

The objective of this study was to evaluate the effects of different surface treatments on the microshear bond strength (µSBS) of resin cements to zirconia. Twenty-four zirconia wafers measuring 2.0 × 9.0 × 15.0 mm were sintered and randomly distributed into 3 groups based on the resin cement (n = 8): Panavia F 2.0, NX3, and RelyX Ultimate. The resin cement groups were divided into 4 subgroups based on the surface treatment: a control subgroup (air abrasion with 50-µm alumina particles) and 3 experimental surface treatments (Alloy Primer, Ea-Z-y Primer, and tribochemical silicoating using CoJet Sand). Each surface treatment was applied to the zirconia wafers according to its manufacturer's instructions. The resin cements were mixed and placed in thermoplastic tubes, producing cylinders measuring 0.8 mm in diameter × 2.0 mm in height. Five tubes containing the resin cements were placed on each of the pretreated zirconia wafers, resulting in a sample size of 10 specimens per treatment per resin cement. The luting agents were allowed to cure chemically for 4 minutes and then light cured for 30 seconds. The thermoplastic tubes were removed after 24 hours, and specimens were stored in deionized water (37°C) for 24 hours. A shear force was applied using a wire loop attached to a universal testing machine with a crosshead speed of 0.5 mm/min, and the microshear forces required for failure were recorded. The parametric data were analyzed with a 2-way analysis of variance with post hoc Tukey and Dunnett tests (P < 0.05). The mean (SD) µSBS values ranged from 3.6 (0.9) to 9.3 (2.4) MPa. Surface treatment with Alloy Primer and Ea-Z-y Primer increased the µSBS of the 3 cements compared to their controls, but the difference was not always statistically significant. CoJet Sand only increased the µSBS of Panavia F 2.0. The results suggest that the effects of different surface treatments may be specific for each cement.

Perceptual ability tests correlate to performance on a rudimentary dental anatomy laboratory exercise.

PURPOSE: Objective of this study was to determine if perceptual abilities test (PAT), quantitative reasoning (QR), and academic average (AA) scores predict performance in a rudimentary dental anatomy laboratory exercise. METHODS: First-year dental students (n = 88) completed two identical wax carving exercises during the first and last weeks of the dental anatomy course. After being given detailed instructions and a wax block, students carved a cube and a semilunar shape using the wax subtraction technique. Using a rubric, students self-assessed their work as unsatisfactory, satisfactory, or ideal in the following areas: finish, sharpness, symmetry, and accuracy. Two calibrated and blinded faculty graded the exercise using the same rubric as the students. Cohen's kappa coefficient assessed faculty interrater reliability and student-faculty reliability. Changes in scores between the two exercises were evaluated using Wilcoxon signed rank and paired t-tests. Spearman's correlation coefficient and repeated measures analysis assessed the association between shape carving scores and DAT, QR, and AA scores. RESULTS: Faculty interrater reliability ranged from 0.2554 to 0.4186 for the assessed criteria over the two exercises. Student-faculty rater reliability ranged from 0.1299 to 0.4461. Only PAT scores correlated significantly to higher scores for the four grading criteria for both exercises. Student self-assessment improved with the second exercise. CONCLUSIONS: This rudimentary exercise was useful to identify students early in their dental education who may require more guidance in other manual dexterity courses. Faculties require additional training and calibration. Self-assessment is a life-long process of critical thinking that students are just beginning to learn.

Is there an association between Perceptual Ability Test scores and color vision acuity?

OBJECTIVE: The purpose of this study was to determine if there is an association between Perceptual Ability Test (PAT) results and color vision deficiency (CVD). METHODS: Three consecutive classes of first-year dental students (n = 291) voluntarily participated in the study. The Farnsworth-Munsell 100 Hue Color Vision test (FM-100) was administered to students beneath a Macbeth Judge II viewing booth that provided ideal lighting conditions to ascertain CVD. Results of FM-100 test were recorded as total error scores (TES). Color acuity was scored as superior (TES 0-16), average (TES 20-100), or poor (TES > 100). Additional information of age, sex, ethnicity, and time to complete the FM-100 was obtained. Multiple linear regression was used to determine the association between PAT and CVD while adjusting for age, sex, ethnicity, and time to complete the FM-100 test. RESULTS: TES ranged from 0-244. There were 132 students with superior color acuity, 161 with average, and eight with poor acuity. Females performed better than males on the FM-100 test. Time to complete the FM-100 test ranged from 3:40 minutes to 25:12 minutes. There was a strong relationship between PAT scores and CVD (P = 0.0003). A 1-unit increase in PAT scores was found to result in a 9% decrease in TES; indicating that students with higher PAT scores are less likely to have CVD. CONCLUSION: The PAT may be a preliminary screening instrument to identify students who may have CVD. The FM-100 test can then confirm the presence of CVD. Students with CVD may desire to improve dental shade matching skills through targeted training and education.

Dental dam utilization by dentists in an intramural faculty practice.

Objectives: From casual observation of our colleagues, only a few individuals use the dental dam for operative procedures in their faculty practice. The purpose of this study was to obtain faculty perceptions of the dental dam, quantify its utilization in their intramural faculty practice, and determine the factors that influence dental dam usage. Material and Methods: A survey containing 11 questions was sent to 19 faculty members who teach full time and maintain an intramural dental practice involving operative dentistry. Thirty electronic dental health records of the 19 providers were reviewed to gather the following information from restorative procedures they completed: isolation methods, tooth location and involved surfaces, and dental restorative material. Results: Overall, dental dam was utilized for 30% of all restorative procedures and was used less than 20% of the time for placement of class II and class III composite resins. Dental dam utilization rate by general dentists was 37% and 17.6% for prosthodontists. Those general dentists with prior history of military dental practice had a utilization rate of 78.6% and nonmilitary dentists only 7.6%. Eight faculty members responded to the questionnaire for a 42% return rate. Those who practiced dentistry in the military strongly agreed that the dental dam is the standard of care, improves their quality of restorative work, and should be documented in the dental record. Conclusions: There were significantly different dental dam utilization rates between general dentists and prosthodontists and between dentists with prior military experience and those without.

Dental Dam and Isovac Usage: Factors Influencing Dental Students' Decisions on Isolation Techniques.

The Isovac system was introduced into the Virginia Commonwealth University dental curriculum with the intention that it would be used as a substitute when the dental dam could not be placed. The aim of this study was to determine the usage and factors that influenced dental students' decisions to use the dental dam or Isovac. All third-and fourth-year dental students (n=210) were asked in 2017 to complete a 26-item survey. The survey asked about students' operative procedures completed using the dental dam and Isovac, their own and their patients' preferences, basic dental dam knowledge, full-time and adjunct faculty recommendations of method, importance of factors influencing their decisions, and anticipated dental dam use after graduation. Comments were also allowed. A total of 164 students responded to the survey, for a 78% response rate. Of the respondents, 58% said they used the Isovac only when they could not use the dental dam. Among the eight general practice groups in which students are educated in delivery of comprehensive dental care, preference was significantly different for placement of Class II restorations. Overall, the students' dental dam knowledge was low, and the knowledge results were not associated with its use. According to the students, recommendations by full-time and adjunct faculty members were significantly different. Factors ranked by importance from greatest to least for determining which isolation method to use were as follows: moisture control, procedure, patient comfort, application time, ease of placement, and attending faculty. Student comments overwhelmingly favored dental dam usage if a dental assistant was available. This study found that dental dam and Isovac use was not standardized among the general practice groups and faculty. Student education, faculty calibration, and increased use of trained dental assistants are required to ensure education is consistent among all general practice groups.

Dental Shade Matching and Value Discernment Abilities of First-Year Dental Students.

PURPOSE: To determine if Farnsworth-Munsell 100 Hue Test, Perceptual Ability Test, gender, age, ethnicity, and time predict dental shade matching and value discernment in first-year dental students. MATERIALS AND METHODS: Farnsworth-Munsell 100 Hue Test was administered to 95 first-year-dental students beneath a Judge II booth (color temperature of 6500°K, and color rendering index of 90). Students also arranged 16 masked shade tabs from a Vita Classic shade guide by value (lightest to darkest) and matched together 16 pairs of masked shade tabs from two Vita Classic shade guides. Ethnicity, age, Perceptual Ability Test scores, gender, and time to complete the tests were recorded. Associations and correlations were investigated using chi-square, Tukey-Kramer HSD, standard least square, and multilinear regression (p < 0.05). RESULTS: Total error scores on the Farnsworth-Munsell 100 Hue Test ranged from 0 to 144. Forty-eight students exhibited superior color acuity, 45 average, and two poor. The mean number of correct answers for matching shade tabs together was 11.6, and 6.1 for arranging the shade tabs by value. Females performed statistically better than males on the Farnsworth-Munsell 100 Hue Test and shade tab matching. Better color discrimination identified by lower total error scores on the Farnsworth-Munsell 100 Hue Test was directly correlated to greater ability to match shade tabs together. Perceptual Ability Test scores had slight significance. As the scores increased there was slightly better performance on the Farnsworth-Munsell 100 Hue Test. Older participants performed better than younger subjects on the value test. No other correlations were significant for any of the tests. CONCLUSIONS: Females and individuals who performed better on the Farnsworth-Munsell 100 Hue Test have improved dental shade-matching ability.

Quantifying Appointments, Treatment Time, Impressions, and Diagnostic Data of Cases Staffed by General Dentists and Prosthodontists in a Dental School Clinic.

The aim of this retrospective study was to quantify differences between general dentists and prosthodontists regarding appointments, treatment time, impressions, and preoperative diagnostic data in teaching predoctoral clinical fixed prosthodontics. Electronic dental records (n=356) of patients treated at one dental school in academic year 2012 were randomly selected for review to obtain the following data: faculty and student demographics, number of appointments and treatment time from preparation to cementation, number of impressions made, completion of oral disease control treatment (ODCT), and presence of preoperative periapical radiographs and diagnostic casts. The results showed that ODCT was completed in 78%, preoperative radiographs were present in 76%, and diagnostic casts made in 53% of the cases reviewed. There was no statistically significant difference in number of appointments, treatment time, or number of final impressions when students were staffed by general dentists or prosthodontists. When students were supervised by multiple faculty members, there was generally an increase in treatment time and number of appointments and final impressions. Although this study found no statistically significant differences between general dentists and prosthodontists regarding the criteria evaluated, the results suggest that faculty development and calibration are needed to ensure ODCT is completed and preoperative radiographs are present prior to initiating fixed prosthodontic procedures.

Quality of Impressions and Work Authorizations Submitted by Dental Students Supervised by Prosthodontists and General Dentists.

Preclinical fixed prosthodontics is taught by Department of Prosthodontics faculty members at Virginia Commonwealth University School of Dentistry; however, 86% of all clinical cases in academic year 2012 were staffed by faculty members from the Department of General Practice. The aims of this retrospective study were to quantify the quality of impressions, accuracy of laboratory work authorizations, and most common errors and to determine if there were differences between the rate of errors in cases supervised by the prosthodontists and the general dentists. A total of 346 Fixed Prosthodontic Laboratory Tracking Sheets for the 2012 academic year were reviewed. The results showed that, overall, 73% of submitted impressions were acceptable at initial evaluation, 16% had to be poured first and re-evaluated for quality prior to pindexing, 7% had multiple impressions submitted for transfer dies, and 4% were rejected for poor quality. There were higher acceptance rates for impressions and work authorizations for cases staffed by prosthodontists than by general dentists, but the differences were not statistically significant (p=0.0584 and p=0.0666, respectively). Regarding the work authorizations, 43% overall did not provide sufficient information or had technical errors that delayed prosthesis fabrication. The most common errors were incorrect mountings, absence of solid casts, inadequate description of margins for porcelain fused to metal crowns, inaccurate die trimming, and margin marking. The percentages of errors in cases supervised by general dentists and prosthodontists were similar for 17 of the 18 types of errors identified; only for margin description was the percentage of errors statistically significantly higher for general dentist-supervised than prosthodontist-supervised cases. These results highlighted the ongoing need for faculty development and calibration to ensure students receive the highest quality education from all faculty members teaching fixed prosthodontics.

Evaluating EDTA as a substitute for phosphoric acid-etching of enamel and dentin.

Matrix metalloproteinases (MMPs) are proteolytic enzymes released when dentin is acid-etched. The enzymes are capable of destroying unprotected collagen fibrils that are not encapsulated by the dentin adhesive. Chlorhexidine applied after etching inhibits the activation of released MMPs, whereas neutral ethylenediamine tetra-acetic acid (EDTA) prevents the release of MMPs. The purpose of this study was to determine if conditioning enamel and dentin with EDTA can be a substitute for treating acid-etching enamel and dentin with chlorhexidine. A column of composite resin was bonded to enamel and dentin after conditioning. Shear bond strengths were evaluated after 48 hours and after accelerated aging for three hours in 12% sodium hypochlorite. Shear bond strengths ranged from 15.6 MP a for accelerated aged EDTA enamel specimens to 26.8 MPa for dentin conditioned with EDTA and tested after 48 hours. A three-way ANOVA and a Tukey HSD test found statistically significant differences among the eight groups and the three independent variables (P < 0.05). EDTA was successfully substituted for phosphoric acid-etched enamel and dentin treated with chlorhexidine. Interactions of conditioning agent and aging were significant for dentin but not for enamel. In an effort to reduce the detrimental effects of MMPs, conditioning enamel and dentin with EDTA is an alternative to treating acid-etched dentin and enamel with chlorhexidine.

Resistance of composite and amalgam core foundations retained with and without pins and bonding agents.

To compare the resistance of different amalgam and composite core foundations retained by pins, bonding agents, or both, 100 molars were mounted in acrylic resin and their occlusal surfaces were reduced to expose dentin. Pins were inserted at the four line angles of the teeth and matrices were placed. Bonding agents were applied according to the manufacturers' instructions. Amalgam was handcondensed and composite was incrementally added and photocured. Restorations were adjusted to produce specimens (n = 10) 5 mm in height with a 1 mm bevel at the axial-occlusal surface. After immersion in deionized water for 24 hours, specimens were loaded at a 45 degree angle on their beveled surfaces in a Universal Testing Machine at a crosshead speed of 0.02 in./minute. ANOVA and Tukey's tests indicated that FluoroCore 2 (with or without pins) was statistically stronger than all other combinations (p < 0.05).

Accuracy and dimensional stability of extended-pour and conventional alginate impression materials.

BACKGROUND: The authors conducted a study to determine if two irreversible hydrocolloid impression materials (Cavex ColorChange, Cavex Holland BV, Haarlem, Netherlands; Jeltrate Plus Antimicrobial Dustless Alginate Impression Material, Dentsply Caulk, Milford, Del.) stored for five days were dimensionally accurate. METHODS: The authors modified Ivorine teeth (Columbia Dentoform, Long Island City, N.Y.) on a Dentoform model (1560 series model, Columbia Dentoform) to allow measurements of tooth and arch width. They made impressions and generated casts immediately and at five additional times. They recorded tooth and arch widths on the casts and compared the measurements with those for the standard model. RESULTS: Compared with measurements for the model, the greatest measured difference in casts was 0.003 inches for Cavex ColorChange (extended-pour alginate) and 0.005 inches for Jeltrate Plus Antimicrobial Dustless Alginate Impression Material (conventional alginate). The percentage of dimensional change ranged from -0.496 to 0.161 percent for the extended-pour alginate and from -0.174 to 0.912 percent for the conventional alginate. CONCLUSIONS: Results of analysis of variance and paired t tests indicated that when generated immediately and at day 5, casts produced from both impression materials were not statistically different from the standard model (P < .05). CLINICAL IMPLICATIONS: When stored properly, both alginate materials can produce accurate impressions at day 5 for diagnostic casts and for fabrication of acrylic appliances.

An evaluation of dentin conditioners for resin-modified glass ionomer cements.

This study sought to test the null hypothesis that there was no difference between three dentin conditioners in terms of how they affected the shear bond strength to dentin of three resin-modified glass ionomer (RMGI) cements. One hundred twenty caries-free third molars were mounted in acrylic resin and their occlusal surfaces were reduced to within 2 mm of their cemento-enamel junction (CEJ). Of the three cements tested, Rely-X Plus (22.7 MPa) and Fuji CEM (19.0 MPa) produced the highest bond strengths when dentin was treated with 37% phosphoric acid and followed by the application of Optibond Solo Plus and BondLink. Among the dentin conditioners tested, Fuji Plus Conditioner increased bond strengths for all three cements more than leaving the smear layer intact, although the increase was not statistically significant. Dentin treated with Cavity Conditioner demonstrated the weakest bond strengths.

Fracture resistance of extensive amalgam restorations retained by pins, amalgapins and amalgam bonding agents.

This in-vitro study compared the resistance of extensive amalgam restorations retained by either four Regular TMS Link Plus pins, four amalgapins, Amalgambond Plus, Amalgambond Plus with HPA, Scotchbond Multi-Purpose Plus, PQ Amalgam, Panavia F 2.0, All-Bond 2 or Resinomer. Ninety caries-free third molars were embedded in acrylic resin and their occlusal surfaces reduced to within 2 mm of their CEJ. Tytin amalgam alloy was hand-condensed into copper band matrices reinforced with modeling compound after placement of mechanical retention or application of the amalgam bonding agents. Modeling compound and copper bands were removed after 24 hours, and the restorations were adjusted to produce specimens 5 mm in height with a 1 mm bevel on the occlusal-axial surface. The specimens were stored in 100% humidity for one month followed by immersion in de-ionized water for 24 hours at 37 degrees C. The specimens were loaded in compression at a 45 degrees angle in an Instron Universal Testing Machine at a crosshead speed of 0.02 inches/minute. The mean failure loads and standard deviations recorded in Newtons were as follows: Amalgambond Plus with HPA 2160N (380), Scotchbond Multi-Purpose Plus 1900N (380), four Amalgapins 1770N (340), PQAmalgam 1660N (270), Panavia F 2.0 1620N (440), Amalgambond Plus 1570N (390), four Regular TMS Link Plus Pins 1325N (406), All-Bond 2 1300N (390) and Resinomer 1245N (310). A one-way ANOVA and Tukey post hoc analysis indicated all amalgam bonding agents were statistically equal to either four Regular TMS Link Plus pins orfour amalgapins.