Effect of Short-Duration, Localized Carbamide Peroxide Application to Remove Enamel Staining on Bond Strength of Resin Cement to Enamel.

UNLABELLED: Objective Peripheral enamel staining is often noticed after removal of long-term veneer or crown provisional restorations. Application of carbamide peroxide (CP) easily removes the stain, but the potential for immediate bonding with a resin-based cement is questionable. This project tested the short-term, shear bond strength of a commercial, photo-curable, resin cement to bovine enamel after application of a 10% concentration of CP placed for different exposure times. MATERIALS AND METHODS: Bovine enamel was flattened and polished. Surfaces had either no CP application (control), or 10% CP applied for 10, 20, or 30 seconds. Teeth were acid-etched, rinsed, dried, and controlled sized stubs of a commercial resin cement were photocured onto the treated surfaces. The shear bond strength of each specimen was determined using a universal testing machine, and results were compared using an analysis of variance at a preset alpha of 0.5 (n = 10/group). RESULTS: No significant differences (p = 0.819) in shear bond strength were found among any CP cleaning treatments or the experimental (nontreated) control. CONCLUSIONS: Short-term application of 10% carbamide peroxide prior to acid etching, to remove enamel stains in teeth prepared to receive ceramic veneers or crowns, does not reduce immediate shear bond strength of resin-based cement to enamel. CLINICAL SIGNIFICANCE: Clinicians can confidently apply 10% CP for short-term, localized stain removal on enamel and not be concerned about affecting subsequent bond strength of a resin-based cement to enamel. (J Esthet Restor Dent, 2016).

Comparison of two low sensitivity whiteners.

PURPOSE: To evaluate two commercially available doctor-supplied, patient-applied, bleaching systems for their ability to whiten the maxillary anterior teeth while at the same time not causing sensitivity. METHODS: 46 participants were randomly assigned to one of two groups: One group received Rembrandt Xtra-Comfort and the other group Nite White Excel 2Z. Bleaching stents were fabricated and the bleaching systems were used following manufacturers' instructions. Participants recorded tray use and any sensitivity on a daily basis. Participants bleached for 2 weeks followed by 2 weeks of no bleaching. Color was evaluated at the first, second and fourth week following the initial delivery of bleaching trays. Color change was measured using the Vita Classic Shade Guide arranged by value. RESULTS: As a group, participants in the NW2Z group bleached for 302 days with a total of 48 days (16%) of sensitivity recorded. The Rembrandt Xtra Comfort group bleached for 313 total days with 97 days (31%) of sensitivity recorded. The difference in sensitivity between the two products proved to be statistically significant (Chi-square analysis, P < or = 0.0001). The median shade change for both products following 2 weeks of active treatment was six tabs. At the 4-week evaluation, the median shade change was 5.5 and 6.0 tabs respectively for Rembrandt and Nite White. There was no statistical difference between the products in respect to shade change.

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.

Effect of solvent type and content on monomer conversion of a model resin system as a thin film.

OBJECTIVE: The purpose of this study was to examine the effect of solvent concentration on the degree of conversion of a model photo-activated resin formulation when placed as a thin film in ambient air. METHODS: A photo-activated co-monomer mixture (ethoxylated bis-GMA/TEGDMA) (Bisco Inc.) was diluted into six concentrations (from 1.0 to 13.0M) with either acetone or ethanol. A controlled volume of diluted, uncured resin was placed on the horizontal surface of an attenuated reflectance unit and the infrared (IR) spectrum obtained. A light emitting diode light-curing source (Bluephase, Ivoclar/Vivadent) then immediately irradiated the specimen for 10s (n=5). Five minutes after exposure, IR spectra of the cured material were obtained, and monomer conversions were calculated using standard methods that monitored changes in aliphatic-to-aromatic CC absorbance ratios in the uncured and cured states. RESULTS: In the acetone/model resin system, maximum conversion occurred with 2.5-5.0M solvent. In the ethanol/model resin system, conversion peaked at 2.5M solvent. Above 5.0M solvent, conversion values declined rapidly for both solvents. A 13.0-M solution resulted in near 0% conversion for both solvents. At 2.5 and 5.0M acetone, conversions exceeded those of equivalent concentrations of the ethanol-based system. CONCLUSIONS: For both an acetone- and ethanol-solvated model resin system, conversion did not immediately decrease with addition of solvent, but instead increased over that of the model resin alone. At higher solvent content (greater than 2.5M ethanol and 5.0M acetone), conversion rapidly declined, with ethanol causing less conversion at equal-molar solvent concentrations.

Serving the public good: challenges of dental education in the twenty-first century.

The purpose of this study was to explore perceptions of the roles and responsibilities of dental education in serving the public good, and the extent to which they are being met, from the vantage point of leaders at the university and state level. Five questions were developed to gather views on dental education's success in meeting the expectations and needs of the public. Fifty-one interviews were conducted with leaders at seven institutions and with public officials in six states. Overall, dental education was perceived as fulfilling its public purpose in promoting oral health, providing access to care, and conducting relevant research. However, significant areas for improvement were noted including better communication of accomplishments to key stakeholders, graduating a more socially aware, culturally sensitive, and community-oriented dental practitioner, and being a committed partner with other community leaders in improving access to care for all citizens. Current programs aimed at addressing these gaps (e.g., Pipeline, Profession, and Practice program) are discussed. Dental education can address these perceptions only by producing graduates who desire to fulfill their obligations to society and serve the public good.

Using Assessments of Dental Students' Entrepreneurial Self-Efficacy to Aid Practice Management Education.

In the past, the typical practice management curriculum in U.S. dental schools was found to place a heavy emphasis on customer service, whereas areas typically stressed in business entrepreneurship and management courses (e.g., long-range planning, competing strategies, and supplier relationship) received less attention. However, future dentists will likely have many points in their careers at which they must decide whether to begin a new business or to associate with a practice, and entrepreneurial and management training can help them make and implement those decisions. The aim of this exploratory study was to investigate the impact of one dental school's practice management education on students' entrepreneurial self-efficacy (ESE), a construct examined for the first time in dental education. ESE is an individual's belief that he or she is personally capable of planning for, operating, and managing a successful business. In December 2014, all students in all four classes were asked to complete a survey measuring their ESE. The response rates for each class were D1 94%, D2 91%, D3 87%, and D4 79%. The results showed that the mean scores of the fourth-year class were higher on all five examined dimensions than those of the other three classes. The same was true for the mean for each class with the exception of the competency regarding an individual's perception of his or her abilities to deploy and manage human resources, in which the first-year class had a higher score than the fourth-year class (149.07>146.06). The fourth-year class had statistically significant higher scores than the third-year class, consistent with the implementation of practice management courses in the curriculum.

Productivity of Senior Dental Students Engaged in Comprehensive Care: A Seven-Year Follow-Up Study.

The aims of this study were to determine the trend of senior dental students' rate of production of clinical procedures performed in the comprehensive care clinic at one U.S. dental school and to compare that trend to what was reported immediately following inception of that clinic. In addition, total clinic revenues collected were recorded and compared. The periods used for comparisons were 2005 and 2006 combined, the last years before introduction of comprehensive care (called "pre-comp care"); 2007 and 2008 combined, the first two years of comprehensive care (called "post-comp care"); and subsequent years through 2014. The number of procedures and total charges were tracked in the electronic health record, and the total number of student-hours was calculated by multiplying the number of students in the class by the total number of available clinic hours. The rate calculated in this way was then multiplied by a factor of 1,000 for ease of interpretation. The results showed a generally upward trend and a significant increase from post-comp care to 2014 for all procedures combined and for indirect restorations. There was a generally downward trend and a significant decrease from post-comp care to 2014 for direct restorations, extractions, and root planing. There was some up and down fluctuation but no significant change from post-comp care to 2014 for exams. In terms of all procedures, the rate per student/1,000 clinic hours increased from approximately 227 to 419, an 85% increase over seven years. These results show that implementation of the comprehensive care clinic model of clinical education has increased the total clinical productivity of senior dental students at this dental school. Additional studies are indicated to determine the proper balance between a quality education and the financial capabilities of the institution.

Injury reports in a dental school: a two-year overview.

As teaching institutions, it is vital for dental schools to collect data on accidental injuries to identify potential problems, improve the quality of care of patients, and educate future practitioners about risk management. Our data reveal important trends concerning such injuries. These data were compiled over a two-year period (2001-03) from accident reports at one dental school. We categorized the accidents as follows: source (instrument causing the injury), recipient of injury, time of day, location within the dental school where the injury occurred, and body part injured. The population examined in this study consisted of predoctoral and postdoctoral dental students, staff, faculty, and patients of the dental school. The majority of injuries occurred in the predoctoral clinic toward the middle to the end of the scheduled clinic periods. The instrument most likely involved was a needle, and the body part most commonly injured was a finger. The collection and analysis of injury data may be used to identify trends that will aid in the prediction and prevention of these injuries and, at a national level, serve as a benchmark that other dental schools can employ to assess their relative frequency of injury.

LED curing lights--what's new?

Technological changes to blue light-emitting diode (LED) light-curing units have taken place at an accelerated rate. The lighting industry, however, has not yet improved output levels of blue chip design used in dental LED units as quickly. In fact, the same 5 watt source has been offered since 1992. The next step in technology advancement is the use of conventional, contemporary chips with improved output levels. These levels may arise from supplying greater electrical power to the chip, and must be accompanied by designs that will reduce internal chip heat to avoid permanent damage. A new LED light design uses periodic level shifting (PLS) to intermittently increase chip output levels over those of baseline. In doing so, maximal output from the chip can be achieved, but not at the risk of destroying the source. This article describes the current state of LED light units, discusses the strategy of chip design and limitations, and presents a description of an LED recently introduced that uses PLS technology.

The Validity of Using E4D Compare's "% Comparison" to Assess Crown Preparations in Preclinical Dental Education.

When a dental school is deciding which technology to introduce into a curriculum, it is important to identify the educational goals for the system. The authors' primary goal for the use of a computer-aided resource was to offer students another way to assess their performance, to enhance their learning, and to potentially decrease their learning curve in the preclinical environment prior to using the technique in clinical patient care. The aim of this study was to examine the validity of the "% Comparison" numbers derived from the E4D Compare software program. Three practical examinations were administered to a class of 82 students at one U.S. dental school over a six-week period. The grading of the practical examinations was performed with individual faculty members being responsible for evaluating specific aspects of each preparation. A digital image of each student's practical examination tooth was then obtained and compared to the digital image of an ideal preparation. The preparations were compared, and the "% Comparison" was recorded at five tolerance levels. Spearman's correlation coefficient (SCC) was used to measure the agreement in rankings between the faculty scores on practical exams 1-3 and the scores obtained using E4D Compare at the different tolerance levels. The SCC values for practical exams 2 and 3 were all between 0.2 and 0.4; for practical exam 1, the SCC values ranged from 0.47 to 0.56. There was no correlation between the faculty scores and the numbers given by the "% Comparison" of the software.

Effect of Employing Different Typodonts When Using E4D Compare for Dental Student Assessment.

The use of computers to aid in instruction and help decrease the subjective component of assessment is steadily increasing. One of the potential barriers to the effective utilization of CAD/CAM technology for assessment purposes is the efficient scanning of the teeth being used for comparison. The purpose of this pilot study was to determine if the use of different typodonts, of the same make and model, has any significant effect on the percent comparison results when using E4D Compare. Tooth #30 was prepared by a faculty member to represent what dental students at Georgia Regents University are taught as the ideal preparation for a full gold crown. Ten typodonts of the same make and model were selected for comparison. Three different examples of students' preparations were scanned and compared to the ideal preparation. Each of the three student preparations was subjected to ten trials (occasions), one for each typodont, at five tolerance levels: 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, and 0.5 mm. The intraclass correlation coefficient (ICC) was used to measure the intrarater agreement among the typodonts at the various tolerance levels. The agreement coefficients (0.971-0.984) indicated very little variability attributable to the use of a different typodont. The high agreement coefficients achieved using different typodonts of the same make and model provide evidence for the interchangeability of typodonts when assessing a student's performance in the preclinical simulation environment.

Inter- and Intrarater Reliability Using Different Software Versions of E4D Compare in Dental Education.

The problems associated with intra- and interexaminer reliability when assessing preclinical performance continue to hinder dental educators' ability to provide accurate and meaningful feedback to students. Many studies have been conducted to evaluate the validity of utilizing various technologies to assist educators in achieving that goal. The purpose of this study was to compare two different versions of E4D Compare software to determine if either could be expected to deliver consistent and reliable comparative results, independent of the individual utilizing the technology. Five faculty members obtained E4D digital images of students' attempts (sample model) at ideal gold crown preparations for tooth #30 performed on typodont teeth. These images were compared to an ideal (master model) preparation utilizing two versions of E4D Compare software. The percent correlations between and within these faculty members were recorded and averaged. The intraclass correlation coefficient was used to measure both inter- and intrarater agreement among the examiners. The study found that using the older version of E4D Compare did not result in acceptable intra- or interrater agreement among the examiners. However, the newer version of E4D Compare, when combined with the Nevo scanner, resulted in a remarkable degree of agreement both between and within the examiners. These results suggest that consistent and reliable results can be expected when utilizing this technology under the protocol described in this study.

Safety and efficacy of a nightguard bleaching agent containing sodium fluoride and potassium nitrate.

OBJECTIVES: Transient sensitivity during bleaching is generally reported to affect 67% of patients. While most people tolerate this sensitivity, some find it impossible to continue treatment. The purpose of this study was to determine the safety and efficacy of an experimental, low-sensitivity bleaching agent. METHOD AND MATERIALS: Twenty-two participants bleached for a minimum of 6 hours per night over a 2-week period. The bleaching agent used, Experimental Product E, is a 10% carbamide peroxide gel containing potassium nitrate and sodium fluoride. Evaluations were performed at baseline and 1,2,13, and 26 weeks. Color change was measured using a value-ordered Vita classic shade guide and a colorimeter. Sensitivity of the teeth, gingiva, tongue, and/or throat was measured daily using a patient log. RESULTS: The median color change after 2 weeks was eight tabs. Approximately 36% reported sensitivity during the active whitening phase of the study. As a group, participants reported sensitivity during 13.7% of the total days spent whitening. CONCLUSION: Experimental Product E was shown to be safe. Participants experienced minor sensitivity during the active bleaching phase only. Experimental Product E was shown to be an effective bleaching agent for the subjects tested in this study.

Reliability of CAD CAM technology in assessing crown preparations in a preclinical dental school environment.

In order to use CAD CAM (Computer Aided Design, Computer Aided Manufacturing) technology as an assessment tool when evaluating the preclinical performance of dental students, it is imperative that one has confidence in the reliability of the process. In this study, a variety of alignment methods were compared to determine both the consistency and accuracy of each method. Although the "Tooth Dots Diagonal" method exhibited the best precision (coefficient of variation=5.4 percent), it also represented the least accurate method when compared to the other methods tested. Using "Small Dots Diagonal" on the gingiva appears to be the best option, exhibiting an acceptable coefficient of variation (17.6 percent) and a high degree of accuracy in terms of tolerance (mean ± standard deviation=0.163 ± 0.029). Based on the results of this study, further investigation of CAD CAM technology for the purpose of assessment and education of dental students is recommended.

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.

Restorative dentistry productivity of senior students engaged in comprehensive care.

In dental education, various clinical delivery models are used to educate dental students. The quantitative and qualitative measures used to assess the outcomes of these models are varied. Georgia Health Sciences University College of Dental Medicine has adopted a version of a general dentistry comprehensive care dental education hybrid model. Outcome assessments were developed to evaluate the effectiveness of this delivery model. The aim of this study was to compare the number of restorative procedures performed by senior dental students under a discipline-based model versus senior student productivity engaged in comprehensive care as part of a hybrid model. The rate of senior students' productivity in performing various restorative procedures was tracked over four years, and a comparison was made. In the first two years, the seniors operated in a discipline-based model, while in the last two years the seniors operated in a comprehensive care hybrid model. The results showed that there was a significant increase in productivity by the students in terms of direct and indirect restorations. This increase in productivity may indicate that the comprehensive care model may be a more productive model, thereby enhancing clinical experiences for the students, improving operating efficiency for the schools, and ultimately increasing clinical income.