Faculty Bibliography

As the number of dental-related randomized clinical trials (RCTs) increases, there is a need for literature to help investigators inexperienced in conducting RCTs design and implement studies. This commentary describes four "lessons learned" or considerations important in the planning and initial implementation of RCTs in dentistry that, to our knowledge, have not been discussed in the general dental literature describing trial techniques. These considerations are a) preparing or securing a thorough systematic review; b) developing a comprehensive set of study documents; c) designing and testing multiple recruitment strategies; and d) employing a run-in period prior to enrollment. Attention to these considerations in the planning phases of a dental RCT can help ensure that the trial is clinically relevant while also maximizing the likelihood that its implementation will be successful.

PURPOSE/OBJECTIVE:To evaluate the dentin shear bond strength (SBS) of a new two-step etch-and-rinse adhesive system (MPa Direct) using self- and light-cured composites. METHODS:The dentin of 160 bovine teeth was ground to 600 grit. Self- (Bisfil 2B) or light-cured (Filtek Supreme Plus) composite was bonded to dentin using MPa Direct, Adper Single Bond Plus, One-Step Plus, OptiBond Solo Plus, or Prime & Bond NT. For the light-cured composite, MPa Direct was used both with and without the HEMA/glutaraldehyde desensitizer (G5) supplied in the kit. For the self-cured composite, OptiBond Solo Plus and Prime & Bond NT were used with and without their respective self-cure activators. Those two adhesives and MPa Direct also were used with the self-cured composite after removal of the oxygen-inhibited layer from the adhesive. Following storage in water for 24 hours, shear bond strengths were determined using a universal testing machine. The data were subjected to factorial ANOVA and Tukey's test. RESULTS:With the light-cured composite, the mean SBS of MPa Direct was 41.1 MPa. Use of G5 did not significantly affect mean SBS (35.7 MPa). Mean SBS of MPa Direct when used with the self-cured composite was significantly lower (16.6 MPa). However, removal of the oxygen-inhibited layer returned the bond strength (38.9 MPa) to the level obtained using light-cured composite. Both OptiBond Solo Plus and Prime & Bond NT had significantly lower bond strengths when used with the self-cured composite than with the light-cured composite, regardless of whether their self-cure activators were used. Removal of the oxygen-inhibited layer improved the bond strengths of these two adhesives, but the improvement was less than that observed for MPa Direct. Bond strengths of One-Step Plus and Adper Single Bond Plus were not affected by the type of composite resin used.

BACKGROUND:The authors conducted a study to evaluate the clinical performance of a dual-cured, three-step dentin adhesive (OptiBond Dual Cure, Kerr, a subsidiary of Sybron Dental Specialties, Orange, Calif.; no longer on the market) at 12 years. METHODS:The authors restored 100 noncarious cervical lesions without use of macromechanical retention or enamel bevels. In one-half of the lesions (group A), the authors etched only the enamel; in the other half (group B), they etched both enamel and dentin. After etching, they applied a light-cured primer and dual-cured adhesive to enamel and dentin in both groups. They restored the preparations with a resin-based composite. They performed direct evaluations by using modified U.S. Public Health Service criteria at insertion (baseline) and at one year and 12 years after insertion. RESULTS:The 12-year retention rates were 93 percent in group A and 84 percent in group B, for an overall retention rate of 89 percent. Except for marginal discoloration in both groups and retention in group B, the restorations in both groups had Alfa ratings of 88 percent or greater in all of the direct clinical evaluation categories. CONCLUSIONS:The 12-year clinical performance, including retention rate, of a dual-cured dental adhesive was excellent and was not affected by dentin acid-etching. CLINICAL IMPLICATIONS/CONCLUSIONS:This clinical study provides additional evidence for the long-term durability of a three-step etch-and-rinse adhesive in non-carious cervical lesions.

Crown and crown-root fractures of anterior teeth of children are common. Bonding of the crown fragment is a logical restorative treatment option when the trauma results in no or minimal violation of the biological width and when the crown fragment: (1) is retrieved following the trauma; (2) is relatively intact; and (3) adopts well to the remaining tooth. Reattachment of crown tooth fragments can provide favorable and long-lasting esthetics because the tooth's original anatomic form, color, and surface texture are maintained. Reattachment also restores function, provides a positive psychological response, and is a relatively simple procedure. The clinician, however, should clearly inform the patient about the limitations and prognosis of this treatment option. The purpose of this paper is to summarize the current knowledge about crown fragment reattachment and present recommendations for the best functional and esthetic outcomes. The rebonding technique is illustrated in detail with a clinical case report.

The composite resin restoration of permanent incisors with crown fractures is a conservative, timely, and economical treatment option. Several variables can affect the longevity of this type of restoration including: the overall prognosis of the injured tooth, whether the pulp is exposed, the extent of the crown fracture, the restoration's size, the patient's age and occlusion, and future reinjury of the restored tooth. Contemporary adhesives and composites allow clinicians to restore fractured permanent incisors with good predictability, restoring both the esthetics and function of the affected tooth. The purpose of this paper is to discuss the current state of the restoration of permanent incisors with crown fractures using composite resins.

BACKGROUND:The strategies for accomplishing resin adhesion to dentin involve surface conditioning, priming and bonding. One-bottle adhesives combine the priming and bonding functions in a single solution. In this study, the authors compared the eight-year clinical performance of two one-bottle adhesives made by different manufacturers. METHODS:The authors placed a total of 99 Class V restorations using either a filled, ethanol-based adhesive (OptiBond Solo [OS], SDS Kerr, Orange, Calif.) or an unfilled, acetone-based adhesive (Prime & Bond 2.1 [PB] Dentsply Caulk, Milford, Del.) and a hybrid resin-based composite in 33 subjects with noncarious cervical lesions. The authors did not bevel the enamel margins and used no mechanical retention. They evaluated the restorations at baseline and for as long as eight years after placement using modified U.S. Public Health Service criteria. They analyzed differences between groups using appropriate statistical tests. RESULTS:The authors examined 56 restorations after eight years and found retention rates of 69 percent for OS and 59 percent for PB. These rates did not differ statistically (P = .449) and were not significantly affected by subject or lesion characteristics. The authors noted marginal discoloration on 55 percent of the retained OS restorations and on 31 percent of the retained PB restorations, but they detected no secondary caries around any restoration. They noted poor anatomical form and poor marginal adaptation in 15 percent and 40 percent of the retained OS restorations, respectively. CONCLUSIONS:The performance of both adhesives was good during this eight-year clinical trial. The filled, ethanol-based adhesive OS demonstrated slightly better bond durability than did the unfilled, acetone-based adhesive PB, but the difference between the two materials was not statistically significant. CLINICAL IMPLICATIONS/CONCLUSIONS:Despite a high incidence of marginal discoloration, the one-bottle adhesives evaluated in this study provided good clinical retention of Class V restorations without mechanical retention. When the materials are used properly, restorations are retained at an acceptable rate through at least eight years of clinical service.

OBJECTIVE:The purpose of this in vitro study was to evaluate and compare dentin and enamel bond strengths obtained with dual-cure composite luting agents when used with dual-cure dental adhesives. METHODS:Human molars were ground flat to expose enamel (n=80) or dentin (n=80). Specimens in each substrate group were randomly assigned to eight treatment sub-groups, according to four adhesive-luting agent combinations and two test conditions (with or without thermocycling). Pre-polymerized composite resin posts (TPH Spectrum) were luted to either the enamel or dentin surfaces with one of the following adhesive-luting agent combinations: (1) Xeno IV Dual Cure (dual-cure self-etch adhesive) and Calibra (dual-cure luting agent); (2) Prime & Bond NT Dual Cure (dual-cure total-etch adhesive) and Calibra; (3) OptiBond All-in-One Dual Cure (dual-cure self-etch adhesive) and Nexus 2 Dual Syringe (dual-cure luting agent); (4) OptiBond Solo Plus Dual Cure (dual-cure total-etch adhesive) and Nexus 2 Dual Syringe. For each treatment sub-group, half the specimens (n=10) were tested after 24h storage in water at 37 degrees C, and the other half (n=10) were tested after thermocycling for 1800 cycles between water baths held at 5 and 55 degrees C, with a dwell time in each bath of 30s, and a transfer time of 10s. Bond strengths were measured in shear mode, and expressed in MPa. The fracture mode (adhesive, cohesive, mixed) was examined. Data were analyzed for statistical significance with a factorial ANOVA and post hoc tests. RESULTS:Mean enamel bond strengths ranged from 8.4MPa for non-thermocycled OptiBond All-in-One|Nexus 2 to 35.5MPa for non-thermocycled Prime & Bond NT|Calibra. Mean dentin bond strengths ranged from 14.5MPa for non-thermocycled OptiBond Solo Plus|Nexus 2 to 30.9MPa for thermocycled Xeno IV|Calibra. The fracture mode was predominantly adhesive for all groups. CONCLUSIONS:On enamel, the total-etch adhesives performed better than their self-etch counterparts, while in dentin, the opposite was found, i.e., the self-etch adhesives performed better than their total-etch counterparts. Thermocycling for 1800 cycles did not affect the SBS of the materials tested to dentin and enamel.