Change in students' critical thinking over the course of dental education.

PURPOSE: The purpose of this study was to test whether critical thinking changes over the course of dental education by assessing dental students at the beginning and toward the end of their training. METHODS: Dental student participants completed a survey at the beginning of their first year (August 2019) and at the start of their last year of dental school (August 2022). The survey consisted of two instruments designed to measure the disposition and metacognition components of critical thinking. The study used a pretest-posttest design. Paired t tests were used to determine whether critical thinking scores changed over the 3-year period. RESULTS: Surveys were completed by 85 of 94 students (90%) on the pretest and 63 of 93 students (68%) on the posttest. Of the 92 students who were members of the class at both testing periods, data were available for 59 students (64%). There were significant mean decreases in disposition and its tolerance for cognitive complexity subscale, as well as in metacognition and its metacognitive strategies subscale (p < .05). There was no significant mean change in either open-mindedness or metacognitive thinking. CONCLUSION: Results of this study suggest that some aspects of critical thinking (metacognition and disposition) decrease over the course of dental education. Future research should investigate why this is the case, and explore different instructional methods designed to improve critical thinking.

Psychometric properties of an instrument to assess critical thinking disposition and metacognition in dental students.

OBJECTIVE: The purpose of this study was to determine the psychometric properties of instruments designed to assess the critical thinking domains of disposition and metacognition in a dental student population. METHODS: Two instruments originally developed to assess disposition and metacognition domains in undergraduate student populations were administered to dental students from 3 classes in the Spring of 2019. The overall response rate was 73%. Sampling adequacy was established for both domains. Exploratory factor analysis was used to determine underlying dimensions. Criterion validity was established by correlation with traditional measures of academic achievement. RESULTS: Kaiser-Meyer-Olkin index (>0.80) and Bartlett's test of sphericity (P < 0.005) indicated sampling adequacy for both domains. Factor analysis supported a 2-factor solution for Disposition (Level of Open Mindedness and Tolerance for Cognitive Complexity) and a 2-factor solution for Metacognition (Metacognitive Thinking and Metacognitive Strategies). Items loading at 0.4 or higher were retained. Cronbach's alpha was above 0.8 for all but the Metacognitive Thinking subscale, which nonetheless showed adequate reliability (0.65). Reliability for Disposition and Metacognition scales was also above 0.8. CONCLUSION: These results indicate that the instrument has sufficient validity and reliability to support further use in dental education.

A Systematic Review of Critical Thinking Instruments for Use in Dental Education.

Critical thinking is widely recognized as an essential competency in dental education, but there is little agreement on how it should be assessed. The aim of this systematic review was to determine the availability of instruments that could be used to measure critical thinking in dental students and to evaluate psychometric evidence to support their use. In January 2017, an electronic search of both the medical and education literature was performed on nine databases. The search included both keyword and Medical Subject Heading terms for critical thinking, higher education/health sciences education, measurement/assessment, and reproducibility of results. The grey literature was included in the search. The search produced 2,977 unique records. From the title and abstract review, 183 articles were selected for further review, which resulted in 36 articles for data extraction. Ten of these studies sought to evaluate psychometric properties of the instruments used and were subjected to quality assessment. Seven assessment instruments were identified. Of these, three instruments that have not been widely used nor tested in health professions students showed evidence of psychometric strength and appeared to have potential for use in dental education. Further research should focus on the three critical thinking instruments with strong psychometric evidence, with the aim of establishing validity and reliability in the context of dental education.

Loss of tooth structure associated with preparation for two monolithic CAD-CAM complete coverage restorations.

STATEMENT OF PROBLEM: Different techniques are used to fabricate complete coverage restorations. Each fabrication technique requires a specific preparation design that may violate a principle of tooth preparation, that is, conservation of tooth structure. PURPOSE: The purpose of this in vitro study was to compare the volume of loss of mandibular first molar structure associated with a preparation for computer-aided design and computer-aided manufacturing (CAD-CAM) versus conventionally fabricated complete coverage restorations. MATERIALS AND METHODS: Fifty artificial mandibular right first molars were weighed before and after preparation for complete coverage restorations of the following types: complete cast, monolithic zirconia, monolithic pressed lithium disilicate, monolithic milled lithium disilicate, and metal-ceramic crowns (n=10 per method). Tooth mass loss was measured by subtracting the mass after preparation from the mass before the preparation, and tooth volume loss was calculated by dividing the mass by the density of the material. A robust analysis of variance (ANOVA), followed by a post hoc test, was used to compare the volume of tooth loss (α=.01). RESULTS: Mean tooth volume losses were 255.6 mm3, 270.0 mm3, 312.7 mm3, 331.7 mm3, and 309.9 mm3 for complete cast, monolithic zirconia, monolithic pressed lithium disilicate, monolithic milled lithium disilicate, and metal-ceramic crowns, respectively. Teeth prepared for monolithic CAD-CAM zirconia and lithium disilicate crowns did not exhibit a significantly lower (P>.01) decrease in volume loss than with complete cast and monolithic pressed lithium crowns. CONCLUSIONS: Preparation of teeth for monolithic CAD-CAM complete coverage restorations is not associated with a significantly higher volume of tooth loss than their conventionally fabricated counterpart preparations.

Observed infection control compliance in a dental school: A natural experiment.

OBJECTIVE: The objective of this study was to determine student adherence to infection control policies at 1 dental school. A secondary objective was to determine the influence of Ebola virus disease (EVD)-related training on student infection control behaviors. METHODS: An instrument to assess and record infection control behaviors was developed to reflect Centers for Disease Control and Prevention guidelines as well as current teaching. Third- and fourth-year dental students were observed during patient-care appointments and behaviors were recorded and analyzed. Behaviors observed before the EVD outbreak and subsequent mandatory in-service training were compared with behaviors observed after completion of the training. RESULTS: Use of personal protective equipment was nearly universal. Overall compliance with infection control parameters was 88%. However, only a minority of students demonstrated no breaches of protocol. Most violations involved improper mask use and improper glove use during the intraoperative phase of an appointment and failure to wash hands after removing gloves. There were no significant overall differences in observed behavior pre- and post-EVD training. CONCLUSION: Overall compliance with recommendations was high but some areas showed room for improvement. Future training in infection control should focus on these areas. Training related to EVD had no influence on student behavior.

Empathy in Dentistry: How Attitudes and Interaction With Older Adults Make a Difference.

The development of empathy and positive attitudes are essential elements of professional education. This study explored the nature of empathy and its association with attitudes about, and exposure to older patients in a sample of dental students. Students completed an adapted version of the Jefferson Scale of Physician Empathy (JSPE), the Aging Semantic Differential (ASD) and answered questions about their exposure to older people. Factor analysis was used to identify four factors: (1) Empathy is Valuable, (2) Empathy is Demonstrated, (3) Empathy is not Influential, and (4) Empathy is Difficult to Accomplish. Higher empathy scores were related to the ASD subscale attitude of acceptability of aging and to greater exposure to older adults outside of clinical practice. There were no demographic predictors of higher empathy scores.

Microtensile bond strength of different acrylic teeth to high-impact denture base resins.

PURPOSE: This study evaluated the effect of denture base acrylic, denture tooth composition, and ridge-lap surface treatment on the microtensile bond strength (µTBS) of three commercially available denture teeth and two injection denture processing systems. MATERIALS AND METHODS: Sixteen experimental groups were formed (n = 3), according to denture tooth surface treatment (no treatment or surface treatment recommended by the manufacturer), denture base processing technique and acrylic (SR-Ivocap-Ivocap Plus or Success-Lucitone 199), and tooth type-composition at bonding interface (BlueLine DCL-PMMA, Portrait IPN-PMMA, Phonares II-PMMA, Phonares II-NHC). Rectangular bar specimens with a 1 mm(2) cross sectional area were fabricated and subsequently thermocycled at 10,000 cycles between 5°C and 55°C with a 15-second dwell time. Select specimens underwent µTBS testing in a universal testing machine with a 1 kN load cell at 0.5 mm/min crosshead speed. Data were analyzed statistically by two and three-way ANOVA and Tukey post hoc test (α = 0.05). RESULTS: Mean µTBS ranged between 56.2 ± 5.6 and 60.8 ± 5.0 N/mm(2) for the Ivocap Plus specimens and 13.3 ± 5.12 to 60.1 ± 6.0 N/mm(2) for the Lucitone 199 specimens. Among the Ivocap specimens, BlueLine DCL and Phonares II NHC had significantly higher µTBS than Portrait IPN to Ivocap Plus acrylic. There were no statistically significant differences among Blueline, Phonares II PMMA, and Phonares II NHC, or between Phonares II PMMA and Portrait IPN. Within the Luctione 199 specimens, there was a significantly higher µTBS for BlueLine DCL and Phonares II NHC denture teeth with the manufacturer-recommended surface treatment when compared to control surface. BlueLine, Portrait, and Phonares II PMMA groups achieved significantly higher mean µTBS than the Phonares II NHC group. There were no statistically significant differences among BlueLine, Portrait, and Phonares II PMMA groups. CONCLUSION: When evaluating the µTBS of PMMA and NHC denture teeth to base resins, a stronger bond was achieved using materials produced by the same manufacturer. Within the Luctione 199 specimens, the Phonares II NHC group demonstrated significantly lower bond strength than other specimens, suggesting that gross ridge-lap reduction of NHC denture teeth is not recommended if a base acrylic by a different manufacturer from the tooth is going to be used.

Dental students' glucometer experience and attitudes toward diabetes counseling, monitoring, and screening: a comparative study.

The objectives of this study were to compare glucometer experience and attitudes toward counseling, monitoring, and screening for diabetes between two classes of graduating students at one dental school to determine if there were differences by experience and year of graduation. Dental students graduating in 2010 and 2013 completed a survey about their experience with use of a glucometer as well as their attitudes toward and perceived barriers to performing glucose monitoring, screening, and counseling. Response rates for the two classes were 100 percent and 95.7 percent, respectively. Students in the two classes were in general agreement that activities related to glucose monitoring and counseling of patients with diabetes are within the scope and responsibility of the dental profession. Examination of their attitudes toward diabetes monitoring and counseling activities by level of glucometer experience indicated that students with more experience using a glucometer were more likely to consider these activities to be within the scope of dental practice and less likely to perceive barriers to such activities compared to those with little or no experience. In addition, regardless of experience, there was significantly higher endorsement for monitoring of patients who had already been diagnosed than for screening of patients who had not been diagnosed. This study suggests that any strategy to encourage dental students' and dentists' involvement in nontraditional health promotion activities should include ample direct clinical experience with these activities.

Dental students' attitudes toward diabetes counseling, monitoring, and screening.

The main objective of this study was to examine attitudes of dental students toward chairside counseling and monitoring of and screening for diabetes. A secondary objective was to examine the psychometric properties of the survey instrument. First- and fourth-year students at one dental school completed a survey examining attitudes toward and perceived barriers to performing glucose monitoring, screening, and counseling in a dental setting. Surveys were completed by seventy-one of ninety first-year dental students (79 percent) and eighty-six fourth-year students (100 percent) for a total of 157 responses. Factor analysis of the survey instrument resulted in a three-factor solution: scope and responsibility, barriers, and glucometer use. In analyses to determine whether there were differences in attitudes by gender, level of education, or family history of diabetes, no statistically significant effects were seen. The dental students were in general agreement that glucose monitoring of patients diagnosed with diabetes is within the scope and responsibility of the dental profession; however, only a minority endorsed screening of patients who have not been diagnosed with diabetes. Psychometric analysis revealed internal reliability of the survey instrument.

Dental students' attitudes toward tobacco cessation counseling.

The main objective of this study was to determine if level of education, gender, and tobacco history affected attitudes of dental students toward tobacco cessation counseling. A secondary objective was to examine the psychometric properties of the survey instrument. First- and fourth-year dental students at one school of dental medicine completed a survey examining attitudes toward tobacco cessation and perceived barriers to performing tobacco cessation counseling in a dental setting. Analyses were conducted to determine whether there were differences in attitudes by gender, level of education, or personal and family tobacco use. A main effect for education level was discovered. Fourth-year students were more likely than first-year students to consider the prescription of nicotine gum and transdermal patches to be within the scope and responsibility of the dental profession. No significant differences were seen with regard to gender or students' personal and family tobacco histories. Dental students were in general agreement that tobacco cessation counseling is within the responsibility of the dental profession, is within the scope of dental practice, and can be effective. Psychometric analysis revealed reliability of the survey instrument.

Primary stability comparison using piezoelectric or conventional implant site preparation systems in cancellous bone: a pilot study.

PURPOSE: This study compares implant primary stability achieved in cancellous bone after placement in piezoelectric prepared sites versus conventionally drilled sites. MATERIALS AND METHODS: Four bovine ribs were randomly assigned and placed in a water bath at 36.5 °C. Five sites per rib (total n = 20 sites) were prepared using piezoelectric system (test) or conventional drills (control) with twenty 10 × 3.6-mm Implantium implants placed. Using Osstell Mentor quantitative analysis, 5 resonance frequency analysis [implant stability quotient {ISQ}] values per implant were recorded at 5 locations for a total of 100 measurements. RESULTS: Independent t test analysis indicated significant difference in primary stabilities between groups: t (17) = 2.637, P = 0.17, with equal variance assumption satisfied (P = 0.196). Examination of means indicated a higher mean ISQ for piezoelectric than for conventional: 58.9 (+8.55) versus 49.2 (+7.33), respectively. Analysis of variance indicated a significant difference in mean ISQ value by rib. Tukey test indicated significantly higher ISQ values for rib A (test) than ribs B, C (control), and D (test). CONCLUSION: Implant site preparation using the piezoelectric system gives higher implant primary stability in cancellous bone. However, variations in quality across bones may have affected the results.

Comparison of fracture resistance of pressable metal ceramic custom implant abutment with a commercially fabricated CAD/CAM zirconia implant abutment.

STATEMENT OF PROBLEM: The predictable nature of the hot pressing ceramic technique has several applications, but no study was identified that evaluated its application to the fabrication of custom implant abutments. PURPOSE: The purpose of this study was to compare the fracture resistance of an experimentally designed pressable metal ceramic custom implant abutment (PR) with that of a duplicate zirconia abutment (ZR). MATERIALS AND METHODS: Two groups of narrow platform (NP) (Nobel Replace) implant abutment specimens were fabricated (n=10). The experimental abutment (PR) had a metal substructure cast with ceramic alloy (Lodestar) and veneered with leucite pressable glass ceramic (InLine PoM). Each PR abutment was individually scanned and 10 duplicate CAD/CAM ZR abutments were fabricated for the control group. Ceramic crowns (n=20) with the average dimensions of a human lateral incisor were pressed with lithium disilicate glass ceramic (IPS e.max Press) and bonded on the abutments with a resin luting agent (Multilink Automix). The specimens were subjected to thermocycling, cyclic loading, and finally static loading to failure with a computer-controlled Universal Testing Machine. An independent t test (1 sided) determined whether the mean values of the fracture load differed significantly (α=.05) between the 2 groups. RESULTS: No specimen failed during cyclic loading. Upon static loading, the mean (SD) load to failure was significantly higher for the PR group (525.89 [143.547] N) than for the ZR group (413.70 [35.515] N) for internal connection narrow platform bone-level implants (P=.025). Failure was initiated at the screw and internal connection level for both groups. CONCLUSIONS: It is possible to fabricate PR abutments that are stronger than ZR abutments for Nobel Biocare internal connection NP bone-level implants. The screw and the internal connection are the weak links for both groups.

Piezoelectric vs. conventional implant site preparation: ex vivo implant primary stability.

OBJECTIVES: This study aims to determine differences in primary stability between implants placed in cortical bone following Piezoelectric or conventional site preparation, as assessed by resonance frequency analysis (RFA) and reverse torque testing (RTT). MATERIAL AND METHODS: Four fresh bovine ribs were acquired and surgical guides fabricated with five sites per rib (n = 20), for proper site preparation. Implant sites were prepared via conventional drilling technique as per manufacturer's instruction (Implantium) or via Piezoelectric (Mectron) implant site preparation using the Implant Prep kit. Twenty 10 mm long, 3.6 mm diameter Implantium implants were placed with 35 Ncm torque; 10 implants per preparation method. RFA was assessed via the Osstell Mentor. Five values were taken per implant. All implants where subjected to a reverse torque in increasing increments of 5 until 50 Ncm force was reached. RESULTS: The five RFA values per site were averaged and plotted by placement technique. A paired t-test statistical analysis was run. The average RFA values showed no statistical significance between the 10 test (RFA = 69.04 ± 5.11) and 10 control (RFA = 70.94 ± 6.41) sites (P > 0.05). All implants in both groups withstood RTT up to 50 Ncm force without movement and thus showed no statistical differences. CONCLUSION: Results of this ex vivo study imply that the Piezoelectric implant site preparation affords similar primary implant stability in comparison to conventional rotary instrumentation in cortical bone.

Dental students' attitudes about older adults: do type and amount of contact make a difference?

This study was an extension of a previous study that considered dental student attitudes about older adults. In the current study, the association of student interactions with older adults, in both the dental school clinic and daily life, with their attitudes about this group was evaluated using the Aging Semantic Differential. A total of 311 dental students across all four years of academic standing were included in the study. The results showed that students' interactions with older adults outside the clinic did not relate to positive attitudes; however, even after controlling for the age of the student and the frequency, type of individual, and context of interactions with older adults outside the dental clinic, the number of older adult patients seen in the clinic showed a significant positive relationship with attitudes towards older adults. These results reinforce the conclusions drawn in a previous study that dental students' general attitudes about older adults may be changed, but that it is the exposure to older adults in a clinical setting that seems to be more critical in shaping these attitudes.

Oral health of patients with intellectual disabilities: a systematic review.

A systematic review of original studies was conducted to determine if differences in oral health exist between adults who have intellectual disabilities (ID) and the general population. Electronic searching identified 27 studies that met the inclusion criteria. These studies were assessed for strength of evidence. People with ID have poorer oral hygiene and higher prevalence and greater severity of periodontal disease. Caries rates in people with ID are the same as or lower than the general population. However, the rates of untreated caries are consistently higher in people with ID. Two subgroups at especially high risk for oral health problems are people with Down syndrome and people unable to cooperate for routine dental care. Evidence supports the need to develop strategies to increase patient acceptance for routine care, additional training for dentists to provide this care, and the development of more effective preventive strategies to minimize the need for this care.

Dental students' attitudes toward the care of individuals with intellectual disabilities: relationship between instruction and experience.

This study examined the relationship between didactic instruction related to special needs patients and dental students' expectations of and reported comfort levels in treating those with intellectual disabilities. The relationship between students' experience with individuals with intellectual disabilities and their expectations and comfort levels was also assessed. Third-year students were surveyed immediately before and one week, six months, and one year after a lecture on management of patients with developmental disabilities. Students indicated their previous experience with individuals with intellectual disabilities, assessment of their general capabilities (i.e., life function skills) and dental capabilities, and current and anticipated comfort levels related to their treatment. Repeated measures ANOVA indicated significantly higher expectations of general and dental capabilities after instruction (p<0.05), but no change in comfort levels. At one-year follow-up, students' expectations were still significantly higher than at baseline. Regression analyses indicated significant positive relationships between experience and baseline comfort levels (p<0.05), but no significant relationship between experience and expectations of general or dental capabilities. Based on these findings and review of the literature, it is recommended that curricula include experiential learning with reflective components in order to develop students' comfort level in treating special needs populations.

Effect of two connector designs on the fracture resistance of all-ceramic core materials for fixed dental prostheses.

STATEMENT OF PROBLEM: Most all-ceramic fixed dental prostheses (FDPs) fail at the connectors. PURPOSE: The purpose of this study was to determine the effect of 2 connector designs on the fracture resistance of core materials used for all-ceramic FDPs. MATERIAL AND METHODS: Three materials were tested: (1) heat-pressed lithium disilicate glass ceramic (IPS e.max Press (Press)), (2) milled lithium disilicate glass ceramic (IPS e.max CAD (CAD)), and (3) milled yttrium-stabilized tetragonal zirconia polycrystals (Y-TZP) (IPS e.max ZirCAD (ZirCAD)). Specimens were made into 30 x 4 x 4-mm bars to represent 3-unit FDPs. Two connector designs, round (0.60 +/-0.01-mm radius of curvature) and sharp (0.06 +/-0.001-mm radius of curvature), with a 3.00 +/-0.05-mm cross-section for each connector, were studied (n=5). Each specimen was loaded to fracture in a universal testing machine with a crosshead speed of 0.1 mm/min. Data were analyzed with a 2-way univariate ANOVA and Tukey HSD test (alpha=.05). RESULTS: Mean (SD) failure loads for round connector designs were 684.2 (70.1) N for ZirCAD, 260 (7.8) N for CAD, and 172.9 (35.5) N for Press. Mean (SD) failure loads for sharp connector designs were 386.3 (51.5) N for ZirCAD, 87.9 (7.0) N for CAD, and 125.1 (15.1) N for Press. The 2-way univariate ANOVA indicated statistically significant differences (P<.005) for material and connector design, and, also, a significant interaction between material and connector design. Higher maximum failure loads were found for the round connector design when compared to the sharp connector design, for ZirCAD and CAD. However, this difference was not statistically significant for the Press groups. SEM subjective assessment of the fractured specimens revealed that the fracture initiated from the gingival surface (tensile) of the connector toward the pontic (central loading point). CONCLUSIONS: Fracture resistance of ceramic core materials is affected by fabrication technique and connector design. Connector design affected fracture resistance of the milled ceramic, but not the pressed ceramic.

Reliability and accuracy of four dental shade-matching devices.

STATEMENT OF PROBLEM: There are several electronic shade-matching instruments available for clinical use, but the reliability and accuracy of these instruments have not been thoroughly investigated. PURPOSE: The purpose of this in vitro study was to evaluate the reliability and accuracy of 4 dental shade-matching instruments in a standardized environment. MATERIAL AND METHODS: Four shade-matching devices were tested: SpectroShade, ShadeVision, VITA Easyshade, and ShadeScan. Color measurements were made of 3 commercial shade guides (Vitapan Classical, Vitapan 3D-Master, and Chromascop). Shade tabs were placed in the middle of a gingival matrix (Shofu GUMY) with shade tabs of the same nominal shade from additional shade guides placed on both sides. Measurements were made of the central region of the shade tab positioned inside a black box. For the reliability assessment, each shade tab from each of the 3 shade guide types was measured 10 times. For the accuracy assessment, each shade tab from 10 guides of each of the 3 types evaluated was measured once. Differences in reliability and accuracy were evaluated using the Standard Normal z test (2 sided) (alpha=.05) with Bonferroni correction. RESULTS: Reliability of devices was as follows: ShadeVision, 99.0%; SpectroShade, 96.9%; VITA Easyshade, 96.4%; and ShadeScan, 87.4%. A significant difference in reliability was found between ShadeVision and ShadeScan (P=.008). All other comparisons showed similar reliability. Accuracy of devices was as follows: VITA Easyshade, 92.6%; ShadeVision, 84.8%; SpectroShade, 80.2%; and ShadeScan, 66.8%. Significant differences in accuracy were found between all device pairs (P<.001) for all comparisons except for SpectroShade versus ShadeVision (P=.033). CONCLUSIONS: Most devices had similar high reliability (over 96%), indicating predictable shade values from repeated measurements. However, there was more variability in accuracy among devices (67-93%), and differences in accuracy were seen with most device comparisons.

Factors that influence dental students' attitudes about older adults.

Our study considered dental students' general attitudes towards older persons using the Aging Semantic Differential. The influence of age, gender, cohort, education, and academic exposure on general attitudes towards older adults was evaluated using a total of 328 dental students across all four years of academic standing. Students were assessed in the fall and spring semesters. The results showed differential responding on the four subscales, with slight positive ratings on the autonomy, acceptability, and integrity subscales and a slight negative rating for instrumentality. Females expressed more negative attitudes than their male counterparts, with no age differences. There was also no significant impact from a specific, didactic educational component offered to the fourth-year students. However, the fourth-year students were the only group to show positive changes across the full academic year. The results suggest that general attitudes can be changed, but didactic (classroom) forms of education alone are insufficient to meaningfully modify students' perceptions of the elderly. Exposure to older adults in a clinical setting appears to be a critical element, as the fourth-year students received much greater exposure to older patients and more intensified interface with their mentors.

Comparison of porcelain surface and flexural strength obtained by microwave and conventional oven glazing.

STATEMENT OF PROBLEM: Although the superior qualities of microwave technology are common knowledge in the industry, effects of microwave glazing of dental ceramics have not been investigated. PURPOSE: The purpose of this study was to investigate the surface roughness and flexural strength achieved by glazing porcelain specimens in a conventional and microwave oven. MATERIAL AND METHODS: Thirty specimens of each type of porcelain (Omega 900 and IPS d.Sign) were fabricated and sintered in a conventional oven. The specimens were further divided into 3 groups (n=10): hand polished (using diamond rotary ceramic polishers), microwave glazed, and conventional oven glazed. Each specimen was evaluated for surface roughness using a profilometer. The flexural strength of each specimen was measured using a universal testing machine. A 2-way ANOVA and Tukey HSD post hoc analysis were used to determine significant intergroup differences in surface roughness (alpha=.05). Flexural strength results were also analyzed using 2-way ANOVA, and the Weibull modulus was determined for each of the 6 groups. The surfaces of the specimens were subjectively evaluated for cracks and porosities using a scanning electron microscope (SEM). RESULTS: A significant difference in surface roughness was found among the surface treatments (P=.02). Follow-up tests showed a significant difference in surface roughness between oven-glazed and microwave-glazed treatments (P=.02). There was a significant difference in flexural strength between the 2 porcelains (P<.005), but no significant difference in flexural strength by surface treatment (P=.48). The Weibull modulus value for the Omega 900 microwave-glazed group was the highest (1.9) as compared to the other groups. CONCLUSIONS: The surface character of microwave-glazed porcelain was superior to oven-glazed porcelain. Omega 900 had an overall higher flexural strength than IPS d.Sign. Weibull distributions of flexural strengths for Omega 900 oven-glazed and microwave-glazed specimens were similar. SEM analysis demonstrated a greater number of surface voids and imperfections in IPS d. Sign as compared to Omega 900.