Critical appraisal. 2015 Update: Approaches to Caries Removal.

Every day in the United States and around the world, complete caries removal in vital, asymptomatic teeth with deep caries lesions ends in unavoidable exposure of the pulp. As a result, the complexity and cost of treatment increase dramatically, and many patients are left with extraction as their only viable option. This Critical Appraisal updates a previous appraisal (2013). Since that review three, systematic reviews of the literature and one large, randomized controlled clinical trial (RCT) have been published. Thus, newer, higher quality evidence is available that supports alternative treatments designed to preserve the vitality of the tooth and thus avoid extraction.

Introducing CAD/CAM into a predoctoral dental curriculum: a case study.

This article describes the decision making and implementation process used at Indiana University School of Dentistry to incorporate a CAD/CAM system into the predoctoral curriculum and presents data regarding the opinions of students and faculty members after one year. Using a non-validated survey instrument, D1 students rated their experience fabricating a CAD/CAM-generated crown. Eighty-eight of the 105 D1 students (84 percent response rate) responded to the four multiple-choice questions, and a varying number provided written responses. Eighty percent of the responding students rated the overall learning experience as good or excellent, and 43 percent judged that they were prepared to fabricate a crown independently. Students' comments about the experience were generally positive. The twelve supervising faculty members were also surveyed after the first year. When asked to evaluate the initial quality of the crowns at placement, they rated 89 to 98 percent of them good or excellent on the measures of marginal fit, axial contours, proximal contacts, and occlusal contacts. In their judgment, CAD/CAM-generated crowns were as good as or better than those received from commercial labs. After one year, the school's experience has been that the performance of these crowns is consistent with the literature and that they are a viable option. Also, the students are enthusiastic about this addition to the curriculum.

Critical appraisal: approaches to caries removal: what the clinical evidence says.

Every day in the United States, complete caries removal in vital, asymptomatic teeth with deep carious lesions ends in unavoidable exposure of the pulp. As a result, the complexity and cost of treatment increases dramatically and many patients are left with extraction as their only viable option. This review appraises evidence which supports alternative treatments designed to preserve the vitality of the tooth and thus avoid extraction.

Including CAD/CAM dentistry in a dental school curriculum.

Shaping a clinical curriculum that is appropriate for novice dentists, is based on high-quality evidence of efficacy, yet reflects current practices is challenging. CAD/CAM units have been available to dentists since the late '80s. Recent improvements in the software, hardware and the clinical performance of available all-ceramic blocks have keyed a surge in interest. Based on a careful review of the systems available and, equally importantly, a review of the research regarding the longevity of reinforced glass ceramics, IUSD decided to add training on the use of the E4D CAD/CAM system to the curriculum. Students now receive lectures, preclinical hands-on training and clinical experience in fabricating all-ceramic restorations. At present any student who is interested in providing an all-ceramic restoration for his/her patient can do so using our CAD/CAM system. In a little less than one year our undergraduate dental students have provided 125 all-ceramic crowns to their patients. Clinical faculty have been impressed with the marginal fit and esthetics of the crowns. Finally, with students designing, milling, sintering and staining the restorations the CAD/CAM systems has reduced lab costs significantly.

Effect of a nano-hydroxyapatite paste on bleaching-related tooth sensitivity.

STATEMENT OF THE PROBLEM: Bleaching-related tooth sensitivity has been shown to be facilitated by the presence of enamel defects. A nano-hydroxyapatite (n-HAP) paste has been shown to repair these defects. PURPOSE OF THE STUDY: Using a randomized clinical trial, an n-HAP paste was investigated to determine its efficacy in reducing bleaching-related tooth sensitivity. METHODS AND MATERIALS: An n-HAP paste (Renamel AfterBleach, Sangi Co., Ltd., Tokyo, Japan) and a placebo (zero-HAP) were randomly assigned for use in 42 participants. A 7% hydrogen peroxide gel was used twice daily for 14 days, with use of assigned desensitizer for 5 minutes immediately following. A diary was completed daily for 4 weeks to note: use of the agents and sensitivity on a visual analog scale (VAS). Three aspects of tooth sensitivity were investigated: percentage of participants; number of days; and intensity level. Color change was assessed. RESULTS: For Groups zero-HAP and n-HAP, respectively, 51 and 29% of participants reported tooth sensitivity (p = 0.06). Days of sensitivity were 76 and 36, respectively (p = 0.001). Change in VAS score from baseline trended higher for group zero-HAP (p = 0.16). Color change was equivalent. DISCUSSION: The data trend indicated group n-HAP experienced less sensitivity over all three measures. Only the number of days of sensitivity was statistically significant. CONCLUSION: Within the limits of the study it can be concluded that the use of the n-HAP paste was associated with a statistically significant reduction in the number of days of tooth sensitivity experienced during active bleaching. CLINICAL RELEVANCE: For those using a tooth whitener without a desensitizing agent, this study indicates that a paste containing nano-hydroxyapatite crystal can effectively reduce the duration of tooth sensitivity.

Treatment of herpes labialis: comparison of two OTC drugs and untreated controls.

STATEMENT OF THE PROBLEM: Rapid resolution of active herpes labialis lesions is of great benefit to the patient not only in terms of controlling pain and disfigurement, but in disruption of needed dental treatment. PURPOSE OF THE STUDY: Using three groups, this retrospective study investigated the time required to complete healing and the loss of discomfort. METHODS AND MATERIALS: Based on 180 completed surveys, responses were divided into three groups: One group used Abreva (GlaxoSmithKline, Parsippany, NJ, USA). The second used Viroxyn (Quadex Pharmaceuticals, West Jordan, UT, USA). The third group, the Control group, consisted of untreated lesions. All three groups were asked about past experiences with lesions treated using Abreva and/or Viroxyn, and lesions which were left untreated. In addition, 58 participants who had used Viroxyn only responded. Participants were provided standardized responses from which to choose. RESULTS: For both the time to healing and time to loss of discomfort, participants in both the Abreva and Viroxyn groups experienced significant improvements. Relative to the Abreva, Viroxyn provided significant improvement in both outcomes (all t-tests; all p < 0.001). Relative to the Control group, Viroxyn and Abreva offered an 8.0 and 4.0 day reduction in time to healing, respectively. Loss of discomfort occurred within 3.0 days and 1 hour for Abreva and Viroxyn, respectively. CONCLUSION: Relative to the untreated controls, both Abreva and Viroxyn offered a significant reduction in both the time to healing and time to loss of discomfort. Furthermore, Viroxyn offered a significant reduction relative to Abreva. .

Critical appraisal. Partial caries excavation.

Regular readers will note that we depart from our normal Critical Appraisal format in this issue of the Journal. This particular Critical Appraisal resembles an expanded Contemporary Issues feature and describes a protocol for partial caries excavation that was recently implemented in the student clinics of the University of North Carolina (UNC) School of Dentistry.

A case series: herpes simplex virus as an occupational hazard.

STATEMENT OF THE PROBLEM: Herpes labialis infections are common and present a serious risk to the dental team. PURPOSE OF THE STUDY: The purpose is to make dentists aware of the risks involved with treatment of patients with active herpes labialis. In addition, evidence-based risk-management strategies are presented. METHODS AND MATERIALS: The incidence and natural history of herpes simplex virus type 1 (HSV-1) are reviewed. Four previously unreported case histories are presented to illustrate the impact common sequelae of HSV-1 can have on the dental team. The differences between HSV-1 and the blood-borne diseases which are the focus of universal precautions are discussed. In particular, the highly contagious, highly transmissible nature of HSV-1 and its transmission through aerosols are highlighted. Finally, the need to include protection against aerosols in the profession's understanding of universal precautions is noted. RESULTS: The authors suggest limiting the treatment of patients with active lesions to urgent care only, and treating active HSV-1 lesions to reduce time of healing. For four common clinical situations involving HSV-1 infections, evidence-based methods for protecting the dental team and the patient from cross-contamination are also presented. CONCLUSION: While it is clear that the treatment of patients with active herpes labialis lesions increases risk of cross-infection, there are good protocols for controlling this risk. CLINICAL SIGNIFICANCE: By bringing common vectors of cross-infection to light and providing evidence-based protocols for preventing them, this article provides practitioners with positive steps that can be taken for controlling the risk of spreading herpes infections to the dental team.

Critical appraisal. Power bleaching.

From anecdotal reports, many patients and some dentists believe that using a high-concentration whitening agent and an auxiliary light source (i.e., power bleaching) provides the best whitening service available. Some believe that the light provides additional whitening. Some believe that it provides a result that cannot otherwise be obtained. Others believe that it whitens far more quickly. The present review investigates the evidence available to support or refute these claims.

In vivo temperature measurement: tooth preparation and restoration with preheated resin composite.

STATEMENT OF THE PROBLEM: Composite preheating has shown to improve material physical properties in vitro, but no data exist on the use of this technique in vivo during placement. PURPOSE: The study aims to measure in vivo prepared tooth surface temperature during a restorative procedure using resin composite either at room temperature (23.6°C) or preheated to 54.7°C in a commercial compule heating device set to heat at 60°C. METHODS: Class I preparations (N=3) were made on a patient requiring multiple posterior restorations. A probe containing two thermocouples was used to record temperature values at the tooth pulpal floor and 2mm higher (top of the tooth preparation/restoration) after tooth preparation (prep), acid etching (etch), placement and curing of a bonding agent (BA), and during placement of composite used at room temperature (RT) or preheated in a commercial device (Calset(TM) , AdDent Inc., Danbury, CT, USA) set to 60°C. Data were compared with two-way analysis of variance, Tukey-Kramer post hoc test (α=0.05). RESULTS: No significant difference in pulpal floor temperature existed between prep (27.8°±1.3°C) and etch (26.3°±1.3°C), which were significantly lower than BA (30.5°±1.3°C) (p=0.0001). Immediate placement of preheated composite resulted in significantly higher pulpal floor (36.2°±1.9°C) (p=0.0025) and top composite temperatures (38.4°±2.2°C) (p=0.0034) than RT values (30.4°±2.2°C and 29.6°±0.9°C, respectively). CONCLUSIONS: In vivo use and placement of preheated resin composite resulted in temperature increase of 6° to 8°C than room temperature material. These values, however, were much lower than expected. CLINICAL SIGNIFICANCE: Although having many potential benefits, composite preheating may not be as clinically effective in delivering resin of predetermined temperature at the time of cure as laboratory experiments would suggest. Despite only moderate composite temperature increase over use of room temperature material, preheating still provides advantages in terms of ease of handling and placement.

Color differences: polymerized composite and corresponding Vitapan Classical shade tab.

OBJECTIVES: This study compared newer composite resin restorative materials to the Vitapan Classical tabs they purported to represent. METHODS: Five Vitapan Classical tabs were studied: A3.5, B2, C1, C3, and D2 (n=3). These tabs created a variety of levels of lightness, chroma and hue. Each of these five shade tabs was removed from three different shade guides, and an intraoral spectrophotometer was used to capture CIELAB color coordinates. Three separate readings were made and all nine were averaged. The inter-tab color differences were also calculated. Five specimens approximately 4.0mm thick were fabricated for each of the shades studied using five different composite resin materials. Composite specimens were of the same size and shape as target shade tabs, and three separate recordings were made for each of them. This average was compared to five Vitapan Classical shade tabs to calculate the color differences using both CIELAB and CIEDE2000 color difference formulas. Color differences were compared to thresholds for perceptibility and acceptability reported in other studies. RESULTS: CIELAB and CIEDE2000 color differences ranged from 3.9 to 22.8 and from 2.1 to 13.8, respectively. None of the materials proved, an acceptable CIELAB color match to any of the shades tested. CONCLUSION: When various shade tabs of Vitapan Classical shade guides were compared with correspondent tabs made of direct restorative composites, no material/shade combination resulted in an acceptable mismatch relative to the used standard of acceptability. Therefore, evaluated resin composites exhibited poor match compared to target Vitapan Classical tabs.

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.

Comparison of traditional and low sensitivity whiteners.

This placebo-controlled, double-blind randomized clinical trial compared five 10% carbamide peroxide tooth whitening formulations. Three products contained varying concentrations of potassium nitrate as desensitizers. One contained no desensitizers and one was a placebo. During the two weeks of active bleaching, participants used a daily diary to record the number of days of sensitivity from hot, cold, gums, tongue and/or throat. The total number of days of sensitivity experienced by the participants in each group was compared. Participants using the agent with no desensitizers did not experience any more sensitivity than those using the agent containing 3% potassium nitrate. The products that included 0.5% potassium nitrate and 0.5% potassium nitrate and 0.25% sodium fluoride were not associated with any more sensitivity than the placebo group. In addition, the shade tab change from baseline to 11 weeks following cessation of bleaching was compared. Using an active bleaching agent, no difference in color change was noted among the four groups. All four groups were associated with significantly higher color change than the placebo. The addition of a small percentage of potassium nitrate to a 10% carbamide peroxide tooth whitener was shown to significantly reduce postoperative sensitivity without reducing efficacy.

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.

The effect of light curing source on the residual yellowing of resin composites.

PURPOSE: This study evaluated the amount of residual yellow in cured resin composites when polymerizing with either a quartz-tungsten-halogen (QTH) or blue light-emitting diode (LED). MATERIAL AND METHODS: Twelve shades (bleaching to conventional shades) of microfill, hybrid and microhybrid resin composite specimens (n = 10) were polymerized with both light types. All the materials contained only camphorquinone as the photoinitiator. After exposure, the specimens were stored in the dark for 24 hours. Then, the specimen color parameters were recorded (L*, a*, b* and C*(ab)) and color differences (deltaE*(ab)) were determined by examining for changes among the test combinations. Group comparisons were examined using ANOVA and the Tukey-Kramer post-hoc test, and pairwise comparisons were made using the Student's t-tests at a pre-set alpha of 0.05. RESULTS: When a significant difference in the shade of yellow was noted, the QTH light produced a greater yellow tinge than most comparisons using the LED. The potential for producing more residual yellowing could not be anticipated with respect to composite filler classification or shade, as this effect may be more dependent on individual product composition. The extent to which residual yellowing differences were noted between light curing units fell within levels considered detectable by the human eye (deltaE > 2.0). CONCLUSION: The selection of light curing unit to polymerize resin-based restorative materials can have a significant influence on the amount of residual yellow present, with the QTH light tending to leave more yellow than an LED unit.

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.

Evaluation of a standard shade guide for color change after disinfection.

OBJECTIVE: To determine if surface disinfectants cause a change in the shade perception of a standard Classic Vitapan shade guide. METHOD AND MATERIALS: Consistency in shade selection for dental restorations involves many factors, and one of the most important is the shade tabs used in the selection process. Ten shade tabs each of shades B2, D2, C1, and A3.5 were selected from the Classic Vitapan shade guide (Vident). All tabs were measured with the EasyShade shade device (Vident) at baseline. Three tabs of each shade were set aside as controls. The other 7 tabs of each shade were treated with the surface disinfectant Cavicide (Metrex Research) for 480 cycles to simulate a year's usage. After each 480 cycles, all the tabs were again measured with the EasyShade. This process was repeated to simulate 2 and 3 years of use. RESULTS: The data were analyzed to calculate the delta E 2000 for any change. A statistically significant increase was observed in the value (L*) and chroma (C*) after 2 and 3 years of simulated treatments. These changes were not perceptible to the clinician. CONCLUSIONS: The authors suggest that 1 standard shade guide be set aside to compare against those in clinical use to determine when they should be replaced.