The correlation of student performance in preclinical and clinical prosthodontic assessments.
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Tracking student performance in preclinical and clinical courses can be helpful in developing and refining a curriculum. Our objective was to correlate student performance on three fixed prosthodontic examinations taken by eighty junior dental students. Examinations included a knowledge-based objective structured clinical examination (OSCE), a manual skills exercise completed on a typodont (Typodont), and a competency casting exam (Casting CE) on a patient. Multiple regression analysis indicated that the OSCE and Typodont exam scores, as independent variables, were not statistically significant predictors (P=0.07; P=0.87, respectively) of Casting CE exam performance, which was the dependent variable. Correlations were weak for the OSCE (r=0.21) and nearly nonexistent for the Typodont exam(r=0.03) when compared to the Casting CE. Our results indicate a weak correlation between an OSCE-based knowledge exam measuring students' knowledge of critical errors in preparations and castings and a competency exam involving the preparation of a full veneer crown. Results also indicate virtually no correlation between a typodont preparation examination designed to provide a measure of students' clinical skill and a clinical competency exam involving the preparation of a full crown. (+info)
Allied restorative functions training in Minnesota: a case study.
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In 2003, the Minnesota Dental Practice Act was modified to allow dental hygienists and assistants to place amalgam, composite, glass ionomer, and stainless steel crowns. The concept of utilizing allied professionals to perform expanded functions has been suggested as a way to increase access to care and productivity. A continuing education course was offered to provide required certification for interested dental practitioners (N=12). The objectives of this study were to examine confidence levels and effectiveness of the continuing education program. Pre- and post-course restorative content knowledge, along with confidence levels in knowledge, technical skills, and the ability to implement skills were measured. A matched pairs t-test found a significant increase in participants' restorative content knowledge (p<.001). Wilcoxen signed rank tests revealed an increase in confidence in all content knowledge (p<.01) and technical skill (p<.05) categories. Participants did not significantly increase in confidence to implement restorative functions skills into practice (p<.7). Interview data revealed that participants remain unclear about ways to incorporate restorative functions into the schedule. Findings in this case study suggest that content knowledge and confidence levels increase following completion of a restorative functions course. To improve education and training, research is needed to identify why participants' confidence in implementation did not increase. (+info)
Perceptibility and acceptability of CIELAB color differences in computer-simulated teeth.
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OBJECTIVES: To determine the perceptibility and acceptability of tooth color differences using computer-generated pairs of teeth with simulated gingival displayed on a calibrated color monitor using appropriate signal detection theory methodology (SDT). METHODS: Twelve dental professionals (four from each of the following groups: dentists, dental auxiliaries, and fixed prosthodontic technicians) and four dental patients served as subjects. Responses to tooth color differences (DeltaE) were measured on each of the three principal axes of CIELAB color space (L*, a*, and b*). As a control, responses to DeltaE=0 (the false alarm rate) were also measured in the same experimental session. RESULTS: No group differences among subjects were found. All gave 50% match or acceptance points that averaged about 1.0 DeltaE units in the L* and a* directions, and 2.6 units in the b* direction. False alarm rates across all subjects averaged 27% (4-55%) and 28% (0.4-61%), respectively, for perceptibility and acceptability. A reanalysis of the data based on SDT, which takes subjects' false alarm rates into account, gave somewhat larger color difference thresholds. CONCLUSIONS: Color difference thresholds for our simulated teeth are generally in line with and extend results obtained with studies using "real" dental materials. No differences between thresholds for acceptability versus perceptibility were found. Furthermore, subjects often reported color differences when none existed, and this behavior needs to be factored into any determination of quality control standards for the fabrication of dental prostheses. (+info)
Recent advances in materials for all-ceramic restorations.
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The past 3 years of research on materials for all-ceramic veneers, inlays, onlays, single-unit crowns, and multi-unit restorations are reviewed in this article. The primary changes in the field were the proliferation of zirconia-based frameworks and computer-aided fabrication of prostheses, and a trend toward more clinically relevant in vitro test methods. This article includes an overview of ceramic fabrication methods, suggestions for critical assessment of material property data, and a summary of clinical longevity for prostheses constructed of various materials. (+info)
Comparative evaluation of shear bond strength of conventional composite resin and nanocomposite resin to sandblasted primary anterior stainless steel crown.
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To evaluate and compare the shear bond strength of conventional composite resin and nanocomposite resin to sandblasted primary anterior stainless steel crown. The study samples consisted of 30 primary anterior stainless steel crowns (Unitek TM, size R4), embedded in resin blocks with crown, in test groups of 15 samples each. Mounting of the crown was done using resin block with one crown each. Sandblasting was done and the bonding agent Prime and Bond NT (Dentsply) was applied on the labial surface of the primary anterior sandblasted crown. The composite resin and nanocomposite resin were placed into the well of Teflon jig and bonded to Stainless Steel Crowns. The cured samples were placed in distilled water and stored in incubator at 37 degrees C for 48 hours. Shear bond strength was measured using universal testing machine (Hounsefield U.K. Model, with a capacity of 50 KN). Independent sample 't' test revealed a nonsignificant (P < 0.385) difference between mean shear bond strength values of conventional and nanocomposite group. The bond strength values revealed that nanocomposite had slightly higher mean shear bond strength (21.04 +/- 0.56) compared to conventional composite (20.78 +/- 0.60). It was found that conventional composite resin and nanocomposite resin had statistically similar mean shear bond strength, with nanocomposite having little more strength compared to conventional composite. (+info)
Shear bond strength of orthodontic brackets bonded to different ceramic surfaces.
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This study was undertaken to measure the shear bond strength (SBS) of stainless steel brackets bonded to different ceramic surfaces, to compare the SBS of the different ceramics with each other and with conventional ceramo-metal porcelains, and to determine the mode of failure for each group following debonding. A total of 60 ceramic crowns were constructed on extracted teeth and divided into three equal groups as follows: In-Ceram ceramic crowns, IPS-Impress ceramic crowns, and conventional ceramo-metal porcelain. Standard edgewise metal premolar brackets were bonded to the prepared porcelain surfaces. After bonding, all samples were tested in shear mode on an Instron universal testing machine. Statistical analysis was undertaken using analysis of variance, LSD, and chi-squared tests. The results showed that the SBS for the ceramo-metal and the In-Ceram groups were comparable, with mean values of 80.54 +/- 13.44 N and 78.87 +/- 13.47 N, respectively. The IPS-Impress group showed the weakest SBS which averaged 67.40 +/- 8.99 N. This was significantly lower than that of the conventional ceramo-metal porcelain (P < 0.001) and the In-Ceram surface (P < 0.01). The mode of failure in the ceramo-metal group was between the porcelain surface and adhesive and in the other two ceramic groups, between the brackets and adhesive (P < 0.001). The SBS of orthodontic brackets to the three tested ceramic surfaces were adequate for orthodontic use. (+info)
Clinical performance and wear characteristics of veneered lithia-disilicate-based ceramic crowns.
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OBJECTIVES: The objectives of this study were to characterize the clinical performance and wear characteristics of lithia-disilicate-based ceramic crowns. METHODS: Thirty posterior crowns were made using the heat-pressing technique and lithia-disilicate-based core ceramic. Subjects were recalled annually. The quality of crowns and adjacent gingival tissues were examined using nine criteria for acceptability. All crowns were examined and ranked from 4 (Excellent) to 1 (Unacceptable) for each criterion. Impressions were made for replica models at each appointment. Wear characteristics of dental ceramic and enamel were obtained by comparing the surface of the original model with the follow-up model using a laser scanner. RESULTS: Twenty-nine subjects returned for the 1-year recall examination. The maximum clenching force for the 30 subjects ranged from 125 to 815 N. All clinical criteria were ranked good to excellent at the 1-year recall exam and no fractures were observed. The mean occlusal wear volumes for the ceramic crowns after 1 year were 0.19 (0.065)mm3 for premolar sites and 0.34 (0.08)mm3 for molar sites. The mean occlusal wear volumes of opposing enamel after 1 year were 0.21 (0.06)mm3 for premolar teeth and 0.50 (0.22)mm3 for molar teeth. The mean occlusal wear volume of ceramic molar crowns was significantly lower than the volume of enamel wear of the opposing teeth (p+info)
Western Australian dental graduates' perception of preparedness to practice: a five-year follow-up.
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The School of Dentistry in Western Australia developed a pregraduation intern year in which final-year students, having completed their didactic education, undertook a focused clinical experiential program (CEP) over an extended year. This program was implemented for the first time in 2002. The aim of this study was to identify the strengths and weaknesses of the curriculum as perceived by graduates and to compare the perceptions of those graduates who did the CEP to those who did not. A survey with questions based on the graduate outcomes of the dental school was mailed to all graduates from 2000, 2001 (did not complete CEP), and 2004 (completed CEP). The response rate was 66 percent (n=57) and included twenty-nine respondents who graduated before implementation of the CEP and twenty-eight who completed the CEP. Most respondents (80 percent) were in the twenty to twenty-nine age group, and there were slightly more males (53 percent). Learning outcome items with the highest mean scores were practicing universal precautions (4.2), behaving ethically (4.2), and demonstrating a satisfactory level of core dental knowledge (4.2). Practical skills outcomes with the highest scores were amalgam restorations (4.3), anterior endodontics (4.3), and single crowns (3.9). When comparing the respondents who did CEP (51 percent) with those who did not (49 percent), there were few significant differences. The general findings from this survey were that most graduates, whether completing the CEP or not, perceived themselves to be prepared, competent, and confident to practice as dentists and were most confident in managing problems that they most frequently encountered during training. (+info)