Shear strengths of ten commercial dentin bonding agents

Physical properties of root cementum: part 2. Effect of different storage methods

This study examined the effect of 5 disinfection and storage protocols over different time periods on the hardness and elastic modulus of human premolar cementum. The sample consisted of 20 first premolars, which were divided into 5 groups of 4 teeth and stored in 1 of the following ways: (1) Miltons solution (1% sodium hypochlorite) for 10 minutes, (2) Miltons solution for 24 hours, (3) 70% alcohol, (4) desiccation, or (5) Milli Q (deionized water, Millipore, Bedford, Mass). Teeth in groups 1 and 2 were initially stored in Milli Q, tested within 6 hours, placed in their respective media, and retested. Groups 3, 4, and 5 were tested within 6 hours, then at 1 month, 2 months, and 3 months after extraction. Group 5 was further studied at 9 months, and 2 teeth in Group 4 were tested at 4 months. The hardness and elastic modulus of cementum was tested with the Ultra-Micro Indentation System (UMIS-2000, Commonwealth Scientific Industrial Research Organization, Australia) on unprepared specimens mounted on a 3-dimensional jig assembly. The results showed that storage in Miltons solution for 10 minutes had no significant effect on the hardness or elastic modulus, whereas storage for 24 hours caused a significant decrease in the hardness of cementum (P =.03). Storage in 70% alcohol for up to 4 months and in Milli Q for up to 9 months had no significant effects. Desiccation caused a significant increase in both the hardness and the elastic modulus from baseline to 3 months (P =.02 and P =.04, respectively), with most changes occurring within the first month. It was concluded that Miltons solution for 10 minutes could be considered an appropriate method for disinfection and removal of periodontal ligament fragments; however, its use for 24 hours should be avoided. Seventy percent alcohol and Milli Q are better storage methods, and desiccation should be avoided.

Shear bond of resin cement to post-cured hybrid composites

Various surface treatments affected the shear bond strength of a dual-cured resin cement to a post-cured composite. Disks of post-cured composite inlay 2.0 mm thick by 10.0 mm in diameter, were mounted in acrylic cylinders. Various surface treatments were tested including: 1) smooth material; 2) treated by sandblasting (air abrasion); 3) sandblasting and etching with hydrofluoric acid (HF); 4) sandblasting and silane priming; 5) sandblasting, HF etching and silane priming; 6) HF etching alone; 7) HF etching and silane priming; and 8) silane priming alone. Specimens of dual-cured cement, 4.0 mm in diameter, were light-cured onto the prepared surfaces. The samples were stored in water at 37 degrees C for 7d before shear bond testing. The highest mean shear bond strengths were achieved for specimens with the following surface treatments: 1) by a combination of sandblasting, HF etching and silane priming; 2) sandblasting and HF etching; and 3) sandblasting and silane priming. Most bond failures in these groups were cohesive within the post-cured composite inlay disks. The bond strengths of the specimen in other groups were significantly lower and bond failures were mainly adhesive at the interface between the disk of post-cured composite and dual-cured resin cement.

Effect of storage media on microleakage of five dentin bonding agents

The objective of this study was to investigate the effect of different storage media on microleakage at the gingival margin of mixed Class V composite restorations. Human molars were either used immediately after extraction (control group) or after a 3-4 wk storage period in 1% chloramine, 70% ethanol, 10% formalin, or 0.1% thymol. Class V cavities with cervical margins in cementum or dentin were prepared and restored with a microfill composite using five different dentin bonding agents. After thermocycling (1440 x from 5 degrees C to 55 degrees C) and basic fuchsin staining, the depth of dye penetration at the gingival margins was determined and ranked on a scale of 0 to 4. Class V restorations in teeth stored in formalin showed significantly less microleakage (mean leakage score, MLS = 1.7) than restorations in freshly extracted teeth (control group; MLS = 3.1). Microleakage scores in teeth stored in chloramine (MLS = 2.7), ethanol (MLS = 3.0) or thymol (MLS = 3.2) were not significantly different from the microleakage scores in the control group. The improvement of in vitro efficacy of dentin bonding agents when using extracted teeth stored in formalin is probably a result of collagen cross-linking by formaldehyde. Since such an alteration of the dentin does not reflect the condition of the substrate in vivo, extracted teeth assigned for in vitro evaluation of dentin bonding agents should not be stored in formalin. In teeth stored in 1% chloramine, the sums of ranks and the rank orders of the dentin bonding agents were comparable to those in freshly extracted teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

The characteristics and performance of dentine bonding agents

Several attempts have been made to synthesise dentine bonding systems, but low bonding strength, increased variance, toxicity and poor hydrolytic stability were some of the disadvantages excluding them from being widely approved. However, many dentine bonding systems are considered to be biocompatible and have become commercially available. These adhesives are thought to have one or two bifunctional agents where one part of the molecule is intended to bond to the inorganic part of the dentine (calcium ions of the apatite), or to the organic part of the dentine (amino and hydroxy groups of the collagen), and the methacrylate part of the molecule is intended to copolymerise with the restorative resin. This review demonstrates that further work is needed to achieve the synthesis of novel dentine bonding agents which bond chemically to dentine by strong covalent bonds, and which are hydrolytically durable and non-toxic to the oral environment.

Comparison of the shear bond strength of a titanium composite resin material with dentinal bonding agents versus glass ionomer cements

This study compared the in vitro shear bond strength of an autopolymerizing composite resin system (CR) (Ti-Core) with two third-generation dentinal bonding agents (DBA) (Tenure and Scotchbond 2) to glass ionomer cements (GIC) (Ketac-Silver, GC Miracle Mix, and Ketac-Cem). The experiment was divided in five groups. The shear bond strengths were evaluated on a universal testing apparatus at three different intervals; 15 minutes, 24 hours, and 7 days. Statistically, (two-way analysis of variance), the shear bond strengths from the greatest to least were: Ti-Core CR with Tenure DBA > Ti-Core CR with Scotchbond 2 DBA > Ketac-Silver GIC, GC Miracle Mix GIC > Ketac-Cem GIC. There were no differences in shear bond strengths according to time, and no interactions between groups and time. The shear bond strengths for Tenure DBA with Ti-Core CR were two and a half to three times greater than the silver-filled glass ionomers, Ketac-Silver GIC and GC Miracle Mix GIC. Tenure DBA with Ti-Core CR also had consistently greater shear bond strengths than Scotchbond 2 DBA with Ti-Core CR, and this trend is in agreement with similar research.

Shear bond strengths of ten dentin adhesive systems

This in vitro study tested the shear bond strengths of nine third-generation dentin bonding systems. All of these systems had higher bond strengths than the control, a second-generation agent. Amalgambond and All-Bond had the strongest bonds to dentin, 23.3 +/- 5.7 and 19.3 +/- 5.6 MPa, respectively. Clearfil Photo Bond and Prisma Universal Bond 3 had intermediate bond strengths (approximately 13 MPa). Gluma, PowerBond, Scotchbond 2, Tenure, and XR-Bond all had mean shear bond strengths of less than 8 MPa.

Effect of tooth storage and cavity cleansing on cervical gap formation in Class II glass-ionomer/composite restorations

Class II cavities with the cervical margin just below the C-E junction and with two cervical retention grooves were prepared in intact human premolars, 31 cavities in teeth stored frozen and 29 cavities in teeth stored in 1% chloramine solution. The teeth from both storage conditions were assigned to two groups; in one group, the cavities were cleaned with a water spray, in the other group, with a cleaner containing 0.2% EDTA and 1% NaF. All cavities were lined with Vitrebond and restored with P50. Cervical contraction gaps were disclosed by a fluorescent resin penetration technique. The length and width of each gap were analysed. A contraction gap was revealed in 17 of the 31 cavities in teeth stored frozen (54.8%) and in 22 of the 29 restorations in the teeth stored in chloramine (75.8%). The width of the gap was significantly greater in teeth stored in chloramine (p = 0.0004). No statistical difference in gap formation was found between cavities cleaned with water or with the detergent containing 0.2% EDTA and sodium fluoride. Since the cavity cleansing procedure was not a significant factor in gap formation, apparently removing the superficial smear layer with the cavity cleaner does not impair the bonding of Vitrebond to the dentin. However, gap formation appeared to be significantly affected by the storage conditions of the extracted teeth. It is suggested that teeth to be used in bond strength and leakage experiments should be stored frozen rather than stored in 1% chloramine solution.

Examining tooth flexure effects on cervical restorations: a two-year clinical study

This study evaluated the clinical performance of dentinal adhesives in seven various material/technique combinations. No statistically significant differences were observed among the restorative combinations, or among technique variables after two years in terms of retention, sensitivity or USPHS categories. However, other factors related to tooth flexure--such as occlusal stress, patient age, restorative material and restoration location--showed statistically significant associations with retention failures. These results support a tooth flexural theory of restoration retention.

Clinical performance of dentine bonding agents in the enamel-etched Class V abrasion lesion

Ninety-three non-undercut cervical abrasion lesions were restored with one of five dentine bonding agents and composite resin, using enamel etching to supplement retention. The restorations were reviewed at approximately one, six, 12 and 24 months. The loss rate at one year ranged from zero to 50 per cent, and marginal staining became apparent over the one-year period. It is evident that even with enamel etching, some dentine bonding agents are not effective enough to reliably retain composite in Class V abrasion lesions.

Clinical evaluation of three dentine bonding agents

Three commercial dentine bonding agents were used with composite resin to restore non-undercut Class V abrasion lesions without enamel etching. Patients were reviewed at 3, 6 and 12 months and the integrity and marginal staining of restorations was assessed. The loss incidence of restorations ranged from 18 to 40 per cent at one year, and there was increasing evidence of marginal staining over the evaluation period. Comparisons are made with other commercial dentine bonding agents from previous studies in this series.

Twelve-month clinical study of dentinal adhesives in class V cervical lesions

Recently, numerous resin systems claiming dentinal adhesive properties have been introduced. This study evaluated the clinical performance of two such adhesive resins in seven various material and technique combinations without conventional cavity-retention features. To identify potential risk factors in regard to retention, nonmaterial- and technique-related variables such as patient age and occlusion were also evaluated.