Implementing a Second-Level Observation Unit at a Large Academic Medical Center.

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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.

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.

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.

The effect of chlorine-based disinfectant on wettability of a vinyl polysiloxane impression material.

STATEMENT OF PROBLEM: Extended contact of impression materials with chemical disinfectant could remove surfactant, significantly altering the contact angle and wettability characteristics of an impression material. PURPOSE: The purpose of this study was to determine the effect of contact time of chemical disinfectant solution on the dynamic contact angle of a commercial vinyl polysiloxsane impression material. MATERIAL AND METHODS: Discs (3.5 × 25 mm) of heavy-body and wash consistencies of material (n=5) were fabricated and either left untreated, or subjected to spray treatment with a commercial disinfectant for various lengths of time (1, 20, or 60 minutes, or 24 hours). Treated specimens were washed and dried, after which dynamic contact angle measurements of a water droplet were determined at various points in time after deposition: 0, 2, 5, 10, 15, and 20 seconds. The same wash product was used without added surfactant (control). For a given type of impression material, contact angles were subjected to 1-way ANOVA within each droplet deposition time for all periods of disinfectant contact (α=.05). The Tukey-Kramer post hoc test was applied for pairwise means comparisons. RESULTS: For each impression material type, significant increases in contact angles were found as the duration of disinfectant contact increased, at each measured droplet deposition time point. For both materials containing surfactant, extended contact with chemical disinfectant resulted in increased contact angles that were not significantly different from those of the nonsurfactant-containing control product. CONCLUSIONS: Increasing the contact time between a surfactant-containing impression material and a disinfecting solution can significantly alter the resulting contact angle of the impression material and render it similar to a material depleted of surfactant. Following manufacturer-recommended chemical disinfection times reduces surfactant loss and only minimally affects surface wettability.

A comparison of human raters and an intra-oral spectrophotometer.

Consistently choosing an accurate shade match is far more difficult than it appears. Recently, several electronic shade-matching devices have been marketed. One device is an intraoral spectrophotometer, Easyshade. The current study compared the accuracy and consistency of the Easyshade (ES) device to three clinicians experienced in tooth whitening trials and trained in the use of the Vitapan 3D Master shade. The maxillary anteriors of 16 participants were matched on three separate occasions one month apart. At each appointment, the three clinicians (R1, R2 & R3) and ES independently chose a single 3D Master tab. A trained research assistant used the Easyshade device to record CIE L*, C* and H* and a shade tab. In addition, color differences between shade tabs were calculated using the Delta E 2000 (delta e 00) formula. The CIE L*C*H* data were also used to establish standards for the five lightness groups of the 3D Master. An intrarater agreement was evaluated using an intraclass correlation statistic, and an inter-rater agreement was evaluated using a weighted Kappa statistic. The percentages of exact matches were: ES = 41%; R1 = 27%; R2 = 22% and R3 = 17%. Matches within a half-shade were also calculated. This represents a mismatch that is perceptible but acceptable. The percentages of matches within a half-tab were: ES = 91%; R1 = 69%; R2 = 85% and R3 = 79%. In terms of lightness, the intra-rater agreement was considered to be very good for ES and R2 and good for R1 and R3. For chroma, agreement for ES was considered good, and for the three clinicians, it was considered moderate. The mean color difference for the L*, C*, H* data recorded at each evaluation was 1.5, or only slightly greater than the color difference between the same tab on different guides (1.2). The delta e 00 data were the most accurate data collected, and they were used to establish a standard to which the tab choices of the four raters were compared. A weighted Kappa statistic was performed and, in terms of lightness, agreement was found to be good for all raters. For chroma, agreement was very good for ES and it was good for the clinicians. In terms of the number of exact matches and matches within a half-shade, the performance of ES was at least comparable to, if not better than, the dentists. Statistically, the same was true in terms of consistency and accuracy when making repeated matches of lightness and chroma using the 3D Master shade guide.

Duration and timing of sensitivity related to bleaching.

PROBLEM: Reports of sensitivity vary greatly from one study to another, probably because studies are small. Generally, only the percentage of subjects is reported. PURPOSE: This study reports sensitivity using a large database. We investigated the source, duration, and timing of sensitivity during 14 days of active bleaching. MATERIALS AND METHODS: One hundred and seventy-two people recorded sensitivity from any of the five sources on a daily basis. RESULTS: No one withdrew from the study because of sensitivity. Forty-seven percent of participants experienced sensitivity. Seventy-seven percent had sensitivity of 3 or fewer days. Temperature sensitivity tended to occur later in the 14-day bleaching cycle, and hot and cold sensitivity tended to occur together. CONCLUSIONS: There was great variability in sensitivity levels from person to person. Temperature sensitivity tended to occur later in the active phase of bleaching, whereas irritation of the tongue tended to occur earlier. CLINICAL SIGNIFICANCE: The results from a large group of people are more likely to include a wide cross-section of the population sampled. This data provides practitioners with a better estimate of what their patients are likely to experience. It is estimated that, during 2 weeks of active bleaching, 77% of people will experience 3 or fewer days of sensitivity. On average, sensitivity is short-lived, thus making it is easy to underestimate the importance of discussing sensitivity with patients considering bleaching. However, for some, the duration of sensitivity is much greater and has a very negative impact on satisfaction.

Effect of restoration size on the clinical performance of posterior "packable" resin composites over 18 months.

Fifty predominantly moderate or large Class II or multiple-surface Class I resin composite restorations were placed in molars under rubber dam isolation. The restorative systems used were: Alert Condensable (Jeneric/Pentron) and SureFil (Dentsply/Caulk). The restorations were classified according to size, with 7 small, 25 moderate and 18 large, of which 8 were cusp replacement restorations. Baseline, 6, 12 and 18-month double-blinded clinical evaluations were carried out using modified USPHS criteria. The independent variables: restorative material, restoration size and three other clinical factors, were tested using a Multiple Logistic Regression procedure to determine if any were predictive of failure. Of the 50 restorations, four failed by the 18-month recall, three failed due to fracture of the restoration and one due to secondary caries. Both restorative systems demonstrated a 92% success rate. No association between restoration size (p = 0.99) or restorative material (p = 0.65) and failure was found. Similarly, the additional variables, occlusal contact type, presence of occlusal wear facets and first or second molar, were not predictive of failure.

Effect of temperature on unpolymerized composite resin film thickness.

STATEMENT OF PROBLEM: Room temperature (RT) composite resins are viscous, and this condition may affect the ability of the material to flow and adapt to preparation walls. PURPOSE: The purpose of this study was to compare the film thickness of a variety of commercial composite resins heated prior to light polymerization. The film thickness of these heated materials was also compared to those of flowable products at RT. MATERIAL AND METHODS: Five flowable and 7 conventional composite resins were used: 2 microfills, a nanofill hybrid, 2 submicron hybrids, a trimodal hybrid, and a packable. Composite resin (0.05 mL) was pressed between 2 Mylar-covered glass plates (15 kg) for 180 seconds, light polymerized, and the thickness measured using a micrometer. When comparing conventional composite resin heated to 54 degrees C or 60 degrees C, the RT value was control, while the RT flowable values were control when compared to heated composite resin. (n=5/group). Data were analyzed using 1- and 2-way analysis of variance and the Tukey-Kramer post hoc test (alpha=.05). Correlation of filler content to flow potential was evaluated. Scanning electron microscopic analysis of polymerized specimens was characterized by filler size and shape. RESULTS: Room temperature conventional composite resin values varied in film thickness. Not all preheated products reduced in thickness. Thickness of the nanofill did not reduce, and one of the submicron hybrids reduced the greatest. No correlation existed between composite resin classification, filler content or shape, and film thickness. No difference in thickness existed between composite resins preheated to 54 degrees C and 60 degrees C. Room temperature and preheated conventional composite resin provided film thickness greater than that of flowable materials. CONCLUSIONS: Preheating conventional composite resin yields lower film thickness for some products, but flow cannot be attributed to composite resin classification, filler content, or shape. Preheated composite resin thickness was greater than that of all flowables.

Student accuracy and evaluation of a computer-based audience response system.

We have incorporated an audience response system into our curriculum to increase student interaction in the teaching process. Classroom Performance System (CPS) is a computer-based audience response system that allows students to answer questions posed to the entire class by entering responses on a keypad. The responses are tallied and displayed on the classroom screen for all students to see. The purpose of our study was to determine student accuracy using the system with three different methods of administering questions. A secondary purpose was to assess students' perceptions about using the system. Our hypothesis for the study was that there should be no difference in volunteer accuracy or questionnaire responses to the three methods of gathering responses. Sixty-two dental students volunteered to participate. Using three methods (projected on a screen, verbal, and written), volunteers were given "responses" to enter into the system using CPS wireless remote answering devices. In the projected and verbal formats, the teacher managed the assessment by controlling the pace of input. In the written format, students were given responses on paper to input into the system at their own pace. At the end of the sessions, volunteers completed an anonymous questionnaire regarding their experiences with the system. The accuracy of responses was similar in the teacher-managed assessments (projected and verbal format). There was a statistical difference in the accuracy of responses in the student-managed assessment (p=<0.000001). Questionnaire responses also showed that students preferred teacher-managed assessments. The hypothesis was disproved. The overall response to this audience response system and its methods of gathering information was very positive.

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.

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.

A technique to determine a desired preparation axial inclination.

The guidelines recommended in the literature for the convergence angle of a crown preparation vary from 3 to 24 degrees. There is a lack of guidelines on techniques to achieve a specific axial inclination. The purpose of this article was to present a practical technique, with a diamond rotary cutting instrument of known axial inclination, to determine the diamond rotary cutting instrument angulations required to achieve the desired axial inclination of a preparation.