Adhesive Class VI Resin Composite Restorations of Worn Mandibular Incisal Edges: A Two-year Case Report.

Many authors have advocated retentive tooth preparations for resin composite restorations intended to halt progression of incisal edge attrition with worn concave dentin, probably due to frustration with adhesive restorations being lost from these defects. Unfortunately, this technique further removes the dentin these restorations are intended to preserve. The purpose of this article is to demonstrate a purely adhesive, less invasive technique for restoration of worn concave incisal edges, which includes air particle abrasion and increased etching time for the sclerotic dentin and unprepared enamel. Favorable two-year results for mandibular anterior teeth opposed by natural teeth are reported.

Diagnosis of Pit-and-fissure Caries Using Three-dimensional Scanned Images.

Diagnosis of the extent of pit-and-fissure caries has been subjective and thus difficult to teach and categorize for treatment planning. This in vitro study compares occlusal caries diagnosis of extracted posterior teeth (n=49) using three-dimensional (3D) scanned images vs visual examination, according to the International Caries Detection and Assessment System (ICDAS). The surfaces chosen for study represent all ICDAS classifications. Five experienced restorative faculty members examined scanned images for 60 seconds from a standardized series of views of each surface and scored them independently. One month later, the same teeth were examined visually by the same five raters with magnification and LED headlamps, with compressed air available. Intrarater and interrater agreement and validity were assessed using intraclass correlation coefficients (ICCs). The ICCs, ranging from 0.90 to 0.93, indicated excellent agreement between and within raters and between the raters and the gold standard ICDAS determination. This suggests that both photographs and 3D scans of pits and fissures are equally effective in diagnosing caries.

Use of a Modified Matrix Band Technique to Restore Subgingival Root Caries.

Given the increasing incidence of root caries in the elderly population, clinicians frequently must isolate and restore subgingival preparations. This article demonstrates a technique utilizing a modified Tofflemire matrix band that creates a preparation free of crevicular fluid and blood for restoration with resin-modified glass ionomer cement.

Restorative Technique Selection in Class IV Direct Composite Restorations: A Simplified Method.

Use of the techniques presented here will yield highly esthetic resin composite restorations in minimal time. Although more elaborate composite layering techniques exist and may be used in complex esthetic scenarios, a simplified approach combining two body shades and implementing basic dental anatomy concepts often will deliver highly acceptable esthetic results.

The critical barrier to progress in dentine bonding with the etch-and-rinse technique.

OBJECTIVES: The lack of durability in resin-dentine bonds led to the use of chlorhexidine as MMP-inhibitor to prevent the degradation of hybrid layers. Biomimetic remineralisation is a concept-proven approach in preventing the degradation of resin-dentine bonds. The purpose of this study is to examine the integrity of aged resin-dentine interfaces created with a nanofiller-containing etch-and-rinse adhesive after the application of these two approaches. METHODS: The more established MMP-inhibition approach was examined using a parallel in vivo and in vitro ageing design to facilitate comparison with the biomimetic remineralisation approach using an in vitro ageing design. Specimens bonded without chlorhexidine exhibited extensive degradation of the hybrid layer after 12 months of in vivo ageing. RESULTS: Dissolution of nanofillers could be seen within a water-rich zone within the adhesive layer. Although specimens bonded with chlorhexidine exhibited intact hybrid layers, water-rich regions remained in those hybrid layers and degradation of nanofillers occurred within the adhesive layer. Specimens subjected to in vitro biomimetic remineralisation followed by in vitro ageing demonstrated intrafibrillar collagen remineralisation within hybrid layers and deposition of mineral nanocrystals in nanovoids within the adhesive. CONCLUSIONS: The impact was realized by understanding the lack of an inherent mechanism to remove water from resin-dentine interfaces as the critical barrier to progress in bonding with the etch-and-rinse technique. The experimental biomimetic remineralisation strategy offers a creative solution for incorporating a progressive hydration mechanism to achieve this goal, which warrants its translation into a clinically applicable technique.

In vivo chlorhexidine stabilization of hybrid layers of an acetone-based dentin adhesive.

The current in vivo study evaluated the degradation of dentin hybrid layers in deep occlusal-surface resin composite restorations using TEM. Caries-free premolars scheduled for extraction as part of orthodontic treatment were prepared and restored, then extracted after 12 months. The adhesive used was a single-bottle etch-and-rinse acetone-based product (Prime & Bond NT, Dentsply/Caulk). Control group restorations (n=8) were placed according to the manufacturer's instructions, while the experimental group received application of a 2% solution of chlorhexidine digluconate after etching and rinsing and prior to application of the adhesive. Extensive degradation was observed in all of the teeth in the control group after 12 months, while no degradation was observed in the experimental group. In vitro testing showed no significant difference in immediate microtensile bond strength between the control and experimental adhesive protocols.

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.

Cytotoxicity of endodontic materials over 6-weeks ex vivo.

AIM: To test the hypothesis that extending the time of a traditional ex vivo cytotoxicity test helps to identify trends in the behaviour of root core materials and sealers, which could ultimately aid in predicting their clinical safety and performance. METHODOLOGY: Endodontic sealers and core specimens were initially tested in direct contact with L929 fibroblasts for 72 h. Cell response was estimated by measuring cellular succinate dehydrogenase activity relative to Teflon controls. Cytotoxicity (% of more active cells) was reassessed after 1, 3, 4 and 6 weeks, with the specimens stored in a physiologically balanced salt-solution between tests. RESULTS: Distinct trends in cytotoxicity among both core materials and sealers were observed over the 6-week test. Four of the six sealers and two of the three core materials showed cell viabilities of <30% of Teflon after 6 weeks (>70% cytotoxicity). CONCLUSIONS: The current results suggest that some endodontic materials have an elevated biological risk for extended intervals.

Postoperative sensitivity: a comparison of two bonding agents.

Historically, postoperative pain associated with temperature was considered a thermal conduction problem. More recently, pulpal hydrodynamics has been used to explain this sensitivity. Relative to restorations placed with dentin bonding agents that require a separate etching step, agents that include an acidic primer are believed to result in a better seal of the dentinal tubules. This study compared pain associated with a standardized cold stimulus in two groups of restorations. One group was placed with a self-priming resin that required a separate etch step, the other with a self-etching, self-priming dentin bonding agent. This was a community-based, randomized, double-blind clinical trial. Two hundred and nine restorations were placed for 76 participants. All teeth were asymptomatic at the start of the trial. Immediately following application of a standardized cold stimulus, participants rated the pain for each restored tooth using a Visual Analog Scale (VAS). For each group of restorations, VAS scores at 13 weeks were compared to preoperative scores. In addition, the preoperative score was subtracted from the 13-week score, and the two groups of restorations were compared. For both groups of restorations, the median scores were significantly reduced at 13 weeks. This decrease in the VAS score reflects a reduction in sensitivity below that which existed preoperatively. There was no significant difference between the two groups of restorations in terms of change in sensitivity at 13 weeks.

One-year clinical performance of a resin-modified glass ionomer and a resin composite restorative material in unprepared Class V restorations.

This study evaluated the clinical performance and appearance of a resin-modified glass ionomer and a resin composite over one year. Thirty-seven pairs of restorations of Fuji II LC and Z250/Single Bond were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. Restorations were clinically evaluated at baseline and 6 and 12 months, using modified Ryge/USPHS criteria. No significant difference (p>0.05) was observed in performance of both materials, although retention of the Z250 restorations was below the minimum specified in the ADA Acceptance Program for Dentin and Enamel Adhesives. Little difference in the restorations' appearance was observed.

Two-year clinical performance of a polyacid-modified resin composite and a resin-modified glass-ionomer restorative material.

This study compared the clinical performance of a polyacid-modified resin composite and a resin-modified glass-ionomer restorative material over two years. Thirty-four pairs of restorations of Compoglass and Fuji II LC were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. Restorations were clinically evaluated at baseline, 6, 12, 18 and 24 months using modified Ryge/USPHS criteria. A significantly higher incidence of failed restorations was found with the polyacid-modified resin composite (p < 0.05).