Daniel C.N. Chan

Evaluation of fluoride release from an orthodontic bonding system

Decalcification around brackets is sometimes observed after orthodontic treatment. Fluoride-releasing orthodontic adhesives have been developed in an attempt to reduce the frequency and severity of decalcification. This study evaluated, in vitro, a light-activated, fluoride-releasing composite resin adhesive, FluorEver OBA. The findings indicate that FluorEver OBA released small concentrations of fluoride ions over time. A mean of 2.6 ppm was released on day 1, decreasing to a mean of 0.42 ppm by day 2 and to 0.04 ppm by day 43. The clinical implications of these findings are discussed.

Clinical evaluation of the soft-start (pulse-delay) polymerization technique in class I and II composite restorations

UNLABELLED The polymerization shrinkage of resin composites may affect restoration quality. A double blind, randomized clinical trial was carried out to compare two curing techniques-Soft-Start (SS) and the plasma arc curing light (PAC). The hypothesis that, delaying the gel point (with SS) improves marginal seal, was tested at alpha = 0.05. Also, this report includes two-week, three-month, one-year and two-year results for post-op sensitivity. Twenty informed participants, each needing two Class II and/or complex Class I restorations, gave written consent. All the teeth were trans-illuminated to rule out pre-op crack lines before restoration placement. Fifty Z100-Single Bond restorations (25/SS and 25/PAC) were placed under rubber dam. Protocols: PAC (Control)-incremental curing < 2.0 mm, 2000 mW/cm2 for 10 seconds for all layers, SS (Treatment)-incremental curing <2.0 mm, 600 mW/cm2 for 20 seconds, except the final layer or enamel replacement increment, which was cured as follows-(mW/cm2/time) 200/3 seconds, wait 3 minutes; 200/3 seconds, wait 5 minutes; 600/20 seconds from multiple angles. Sensitivity to a standardized cold stimulus was performed preoperatively at 2 weeks and at 3, 12 and 24 months. Patients rated their sensitivity after stimulus by means of a Visual Analog Scale (VAS). In addition, two independent, calibrated investigators evaluated the restorations clinically at each appointment. There were no significant differences in VAS scores between the two groups at any appointment period (two-way ANOVA; p > 0.05). Several conditions were defined as indicating marginal stress before the start of the trial. At 24 months, there was no significant difference between the SS and PAC groups. CONCLUSION Within the limitations of this study, Class I and II restorations placed with a SS technique did not show significant changes in post-op sensitivity or decreased signs of marginal stress.

A case for rubber dam application--subcutaneous emphysema after Class V procedure.

Clinical Relevance Subcutaneous emphysema after dental treatment occurs frequently, especially in older patients. Dentists should be aware of the etiology, the differential diagnosis and how to avoid and properly treat such situations.

Predictors of non-carious loss of cervical tooth tissues

This Predictor Variables study is designed to determine which one of 11 factors evaluated may be correlated to Non-carious Loss of Cervical Tooth Tissues (NLCTT) using subjects with and without NLCTT. The ultimate objective is to successfully predict the path toward risky behaviors and reduce the incidence of NLCTT.

Utilization of occlusal index and layering technique in class i silorane-based composite restorations

PURPOSE This article describes a technique that uses an occlusal index to restore teeth back to their original contour and anatomy with minimal finishing. A new type of ring-opening silorane composite reported to have less than 1% volumetric shrinkage was used in the restoration. For the silorane-based composite, there is no oxygen-inhibited layer to be polished away. The final composite layer is cured under pressure and further minimizes voids and gap formation. The technique can also be used on multiple posterior restorations under rubber dam isolation. Overall, if used properly, this technique helps the clinician produce superb anatomy and reduces time for posterior composite restorations.

A Simple Method of Preventing Hypersensitivity in Contra-lateral Teeth During Restorative Procedures

Dentin hypersensitivity is a common condition, particularly in patients with gingival recession. Restoring anterior teeth in these patients might involve bilateral anterior segment isolation from the premolar/canine to the contra-lateral teeth, but only with unilateral block anesthesia. Although unilateral isolation would help to reduce exposure to thermal stimuli, it also reduces the improved access bilateral isolation provides. Oftentimes, clinicians only find out that contra-lateral teeth are sensitive after rubber dam isolation and starting the restorative procedure. Air from high speed handpieces, high speed vacuum suction and/or water irrigation will illicit a painful response from the side that is not anesthetized. Such a response often makes the patient uncomfortable and delays the restorative procedure. One solution is to anesthetize both sides of the mandible or maxilla. However, anesthesia carries additional inherent risks and time delays.

Approaches to Caries Removal: What the Clinical Evidence Says: Critical Appraisal

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.