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.

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.

Measurement of clinical wear of two packable composites after 6 months in service.

Original large-particle composites exhibited poor wear characteristics. With the packable composites, there has been a reintroduction of large particles. The clinical wear characteristics of such packable composites are relatively unknown. The purpose of this study was to compare wear between two types of packable composites: Alert (Jeneric Pentron) and Surefil (Dentsply Caulk). Each material was compared with and without a surface sealant. Fifty-two subjects were included. Subjects had to have two to four eligible teeth, be 21 years of age, in good health and in need of moderate to large class 2 restorations on molars, and/or a two-surface class 1 on molars. Wear was assessed, using the Moffa-Lugassy (ML) scale, by evaluating stone models made from polyvinyl siloxane (PVS) impressions taken at baseline and 6 months. Rating was done by four calibrated examiners using a forced consensus model. The use of a surface sealant with Alert significantly reduced the median wear rate at 6 months compared with that of the SureFil restorations.

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).

Constancy of bond strength in 5 single-bottle dentin bonding systems.

OBJECTIVE: Historically, wide variations in the shear bond strength of resin composite bonded to dentin have been reported. The purpose of this study was to compare 5 commercially available single-bottle dentin bonding systems while controlling several sources of variation in shear bond strengths. METHOD AND MATERIALS: Extracted molars were stored for 2 weeks in 0.5% Chloramine T. The teeth were mounted, the occlusal enamel was removed to expose middle dentin, and the exposed dentin was etched and treated according to 1 of 6 protocols. Finally, a cylinder of resin-based composite was bonded to the dentin. After 24 hours, specimens were fractured under shear force, and the results were recorded in megapascals. RESULTS: The type of product used was significantly associated with the mean shear bond strength observed. All products exhibited some degree of variation from specimen to specimen. One product, PQ1, exhibited less variation than the other 4 products. CONCLUSION: PQ1 was found to have a significantly higher mean shear bond strength than the other 4 products tested. There was no significant difference between specimens bonded to dry dentin and specimens bonded to wet dentin when using PQ1.

Effects of sonic toothbrush use on permanent dental luting cements.

The aim of this project was to assess the effects of sonic toothbrushes on commonly used permanent luting cements. While results showed differences between the tensile bond strengths of the three cements, the differences were similar between the two groups: sonic and nonsonic toohbrush exposure. These findings suggest that the sonic toothbrush had no significant effect on the tensile bond strengths of any of the three tested cements.

Informed consent: direct posterior composite versus amalgam.

Survey data were obtained from 144 dentists and 116 patients concerning their attitudes and preferences toward direct composite and amalgam restorations in the posterior segment. Some dentists report that they take the initiative in recommending direct composites in these cases and others report that patients request them. Selection criteria for direct composite posterior restorations are similar to those advocated in the dental literature. Those characteristics of alternative materials emphasized in obtaining informed consent mirror the characteristics of the materials dentists report most often performing. Patients report an interest in tooth-colored restorations and trust dentists' professional opinion, but also express a strong desire for full information as part of informed consent.

Clinical performance of bonded amalgam restorations at 42 months.

BACKGROUND: Despite a lack of data based on clinical research, many positive characteristics have been attributed to the placement of amalgam restorations with an adhesive resin liner. METHODS: For 42 months, and authors followed two groups of subjects who had amalgam restorations placed in a previous study. In this double-blind study, these subjects had been randomly assigned to have amalgam restorations placed with an adhesive liner or with a copal varnish placed under all restorations and a bulk base of zinc phosphate cement for deeper lesions. The authors evaluated anatomical form, marginal adaptation, retention and the presence of secondary caries at six, 18, 30 and 42 months. RESULTS: At 42 months, the authors found that all restorations in both groups still were retained, were free of secondary caries and were rated clinically acceptable. No difference between the groups was found for any category (P > .05; analysis). CONCLUSIONS: Placement of amalgam restorations with adhesive liners was found to produce results equivalent to that of traditional methods over a 42-month period. CLINICAL IMPLICATIONS: Practitioners wary of using new methods that have not undergone thorough clinical testing can feel comfortable placing adhesive liners under amalgam restorations.

Two-year clinical comparison of a microfilled and a hybrid resin-based composite in non-carious Class V lesions.

The purpose of this double-blind clinical trial was to compare the retention rate in noncarious Class V lesions of two resin-based composite restorative materials with contrasting stiffness. Isolation with retraction cord, pressed paper triangles, and cotton rolls was used to closely mimic the procedures generally used in a practice setting. Thirty pairs of restorations were placed, one using Silux Plus and one using Z100. The assignment of material was randomized, and the subjects were unaware of the material used. All restorations were placed with a fourth-generation adhesive liner, Scotchbond Multi-Purpose. Evaluations were performed at baseline, 6, 12, 18, and 24 months by two independent examiners using criteria developed by Cvar and Ryge in a forced consensus model. Examiners were unaware of the restoration's group identity. No difference between the retention rates for the two groups was found after 24 months, bringing into question the role that a material's stiffness plays in determining retention in a noncarious Class V lesion.

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

This study was a 2-year clinical evaluation of a conventional and a resin-modified glass-ionomer restorative material. Thirty-four restorations each of Ketac-Fil and Photac-Fil were placed without tooth preparation in cervical abrasion/abfraction lesions, primarily in premolar teeth. Patients ranged in age from 30 to 73 years, with a median age of 45 years. Isolation for the restorations was accomplished with cotton rolls. Restorations of both materials were retained at the rate of 93%, and both were comparable in appearance, receiving Alfa ratings for more than 85% of the restorations. One occurrence of secondary caries was observed for each material. No significant difference between the materials was observed for any evaluation category (exact binomial test, P > 0.05).

Retention of microfilled and hybrid resin-based composite in noncarious Class 5 lesions: a double-blind, randomized clinical trial.

This double-blind clinical trial was undertaken to compare the retention rate of restorative materials with contrasting stiffness in noncarious class 5 lesions. All restorations were placed using retraction cord and cotton roll isolation to more closely mimic the general practice setting. Thirty subjects with at least two lesions were recruited to participate in the study. Each subject received one restoration using Silux Plus and one using Z100. The assignment of material was randomized, and the subjects were unaware of which tooth had received which material. All restorations were placed with a fourth-generation adhesive liner, Scotchbond Multi-Purpose. Evaluations were performed at baseline, 6, and 12 months by two independent examiners unaware of the restoration's group identity. The restorations were evaluated using criteria developed by Cvar and Ryge in a forced-consensus model. Despite the fact that the two materials have widely different elastic modulus values, after 12 months no difference between the retention rates for the two groups was found, and both groups of restorations performed very well.

Clinical study of tooth shade lightening from dentist-supervised, patient-applied treatment with two 10% carbamide peroxide gels.

PURPOSE: Prescribed, patient-applied tooth lightening agents, or nightguard vital bleaching, typically utilizes a 10% carbamide peroxide agent applied during nocturnal hours. The purpose of this randomized double-blind study was to compare the amount of tooth color change in two groups of subjects using dentist-supervised, patient-applied 10% carbamide peroxide gel. MATERIALS AND METHODS: One group used Opalescence (Ultradent Products Inc., South Jordan, Utah) and the other NiteWhite Excel (Discus Dental, Inc., Los Angeles, California). Evaluation of tooth color for the six maxillary anterior teeth was done using a Vita shade guide at baseline, 1, 2, and 4 weeks. Subjects were instructed to apply the gel nocturnally using a custom-made soft tray 8 hours per day for 2 weeks. The 16 tabs of the shade guide were ranked according to value from darkest to lightest. The number (1-16) that correlated to the shade tab selected as the match for each tooth was the outcome variable. A Kruskal-Wallis one way analysis of variance on ranks was used. RESULTS: The test revealed no statistically significant difference between Opalescence and NiteWhite Excel for lightening the teeth (p = .807). The color change was still significant after 2 weeks without further bleaching activity. The baseline evaluation of the maxillary incisors and canines for all subjects, regardless of group, demonstrated a significant shade difference, with the canines being darker. This difference was not seen after 2 weeks of active bleaching or at the 4-week evaluation. CLINICAL SIGNIFICANCE: In this study comparing bleaching products, patients using Opalescence and NiteWhite Excel experienced a significant change in the color of their teeth relative to baseline values after 2 weeks of active treatment.

Incidence and severity of postoperative pain following routine placement of amalgam restorations.

OBJECTIVE: This study investigated the incidence and severity of postoperative sensitivity, examining several potential sources of pain. METHOD AND MATERIALS: One hundred eighteen subjects were asked about pain that they experienced following an appointment for restoration of a moderate Class I or II carious lesion. The survey required subjects to complete 3 questionnaires, 1, 4, and 7 days posttreatment. Questions covered 9 different potential sources of postoperative pain and the use of pain medication following the dental appointment. RESULTS: A great majority of subjects experienced postoperative pain from at least 1 source, and approximately half of those who reported pain following the appointment found it necessary to take medication for relief. For almost all categories, the level of pain reported at 4 and 7 days was substantially less than that reported after 24 hours. CONCLUSION: Patients commonly experience pain in the first 24 hours after operative treatment. Dentists should consider recommending that patients who are likely to experience postoperative pain take a nonprescription analgesic around the time of the treatment and for 24 hours afterward to prevent discomfort.

1-year clinical evaluation of Compoglass and Fuji II LC in cervical erosion/abfraction lesions.

PURPOSE: This study was undertaken to compare the clinical performance of a polyacid-modified resin-based composite and a resin-modified glass-ionomer restorative material over 1 year. MATERIALS AND METHODS: Thirty-four pairs of restorations of Compoglass (C) and Fuji II LC (F) were placed in 31 patients, with no patient receiving more than two pairs, and with materials assigned at random within the pairs. Caries-free cervical erosion/abfraction lesions of the facial surface were restored without tooth preparation according to manufacturers' instructions, except that tooth structure to be restored was etched with 37% phosphoric acid prior to placement of Compoglass. Restorations were clinically evaluated by two blinded examiners at baseline, 6 months, and 1 year, using modified Ryge/USPHS criteria. Restorations receiving a score of "Charlie" in either retention or secondary caries were classified as failed restorations. The incidence of failures was statistically analyzed as a pairwise comparison, using an exact binomial test. RESULTS: Thirty-one pairs of restorations were available for recall at 1 year. The percentage of Alfa scores for each material in each category were: Retention (C = 84%, F = 100%), Color match (C = 81%, F = 100%), Marginal discoloration (C = 78%, F = 97%), Secondary caries (C = 88%, F = 100%), Anatomic form (C = 92%, F = 100%), and Marginal adaptation (C = 26%, F = 46%). Except for the failed restorations, no other Charlie scores were assigned. A significant difference in the incidence of failed restorations was found between the materials (P = 0.01).

Microleakage of Class V compomer and light-cured glass ionomer restorations.

STATEMENT OF PROBLEM: Resin-modified (light-cured) glass ionomer and polyacid-modified composite resin (compomer) restorations are popular choices for the restoration of root caries and cervical abrasion/erosion lesions, but clinical studies are relatively few and have been published primarily as abstracts. PURPOSE: In the absence of adequate clinical data, the marginal integrity of restorations of the above two types of material was compared in vitro. The microleakage of restorations of two light-cured glass ionomer restorative materials and of one compomer material was evaluated. METHODS AND MATERIAL: Restorations of the three materials were placed in facial and lingual Class V cavity preparations in bovine incisors. All preparations were centered on the cementoenamel junction and were prepared with 45-degree enamel bevels. After thermal cycling, teeth were immersed in methylene blue dye, then sections of the restorations (n = 16) were visually evaluated. RESULTS: Dye penetration was observed at approximately 20% of restoration margins for all three materials, with the greatest incidence of severe leakage in the compomer restorations. CONCLUSION: No significant difference in microleakage among the three materials (ANOVA; p > 0.05) was found.

Effect of gap size and cement type on gingival microleakage in Class V resin composite inlays.

Microleakage along the gingival interface was measured in 52 teeth that had received standardized preparations at a fixed depth of 2.0 mm and were restored with Class V composite inlays. Two fabrication techniques and two types of luting cement were compared. Twenty-six teeth were cemented with a resin-modified glass-ionomer cement, and 26 were cemented with a conventional resin cement. Half of the inlay patterns in each cementation group were fabricated directly on the tooth, and half were fabricated indirectly on stone dies. The resin cement was more significantly effective in preventing leakage than the resin-modified glass-ionomer cement. There was no statistically significant difference between inlay fabrication techniques. For those inlays cemented with the resin cement, the mean leakage was substantially lower for the indirect patterns than for the direct group. Although this difference was not statistically significant, it suggests that the slightly larger interfacial gap resulting from the fabrication of indirect patterns is effective in creating a better seal.

Postoperative pain following bonded amalgam restorations.

Sixty subjects were randomized into two groups. The time, in seconds, that it took subjects to respond to a standardized cold stimulus was recorded at baseline and again 1 week following treatment. During the intervening week subjects filled out three self-report questionnaires about pain from exposure to cold and several other common sources of postoperative pain. These questionnaires were filled out after 1 day, again 3 days after the first questionnaire, and 3 days after the second. Subjects mailed the questionnaires in immediately to provide three independent reports about cold sensitivity. The group receiving an OptiBond adhesive liner under their amalgam restorations was not found to be any less sensitive to cold, either by timed response to a cold stimulus or by self-report of pain, than the group receiving conventional liners and bases.

Reduction of postoperative pain: a double-blind, randomized clinical trial.

The authors investigated the capability of two commonly used basing techniques to reduce postoperative sensitivity. The authors measured the time it took the subjects to respond to a standardized stimulus of cold water (cold response measure, or CRM) at baseline and one week after treatment. The authors found no significant reduction in the mean CRM for the group receiving Amalgambond Plus (Parkell), but they did find a significant decrease in the mean CRM for the group receiving Copalite (Harry J. Bosworth Co.) with or without Vitrebond (3M). The authors concluded that the subjects in the Amalgambond Plus group experienced no more sensitivity to cold at one week postoperative than they did at baseline, while the subjects in the Copalite/Vitrebond group did.

A survey of failure modes in composite resin restorations.

This study was undertaken as a first step in identifying opportunities to decrease the need for replacement of class 3, 4, and 5 composite resin restorations. Data regarding the reasons for original placement or replacement of a restoration, the age of restorations at the time of replacement, and patient/doctor factors that may be associated with a decision to place or replace a restoration were recorded by use of a cross-sectional survey. During a 2-week period 108 dentists recorded reasons for placing or replacing 1360 restorations. Of the 1360 restorations, 42.8% were classified as primary placement and 57.2% as replacement restorations. Of the primary placements 80% were categorized as being due to caries; 9.1% fracture of tooth; 8.4% other (erosion lesions were specified 94% of the time). By class, caries was the dominant cause for class 3 (96.2%); caries and other (erosion) for class 5 (77.3% and 16.4%); fracture of tooth and caries (48.9% and 40.2%) for class 4 restorations.