Bonding durability of using self-etching primer with 4-META/ MMA-TBB resin cement to bond orthodontic brackets

This study determines the bonding durability when a self-etching primer is used with Superbond C&B (a 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butyl borane resin) to bond orthodontic brackets to enamel. Thermocycling test was used to assess bonding durability. Metal brackets were bonded to the phosphoric acid-etched or Megabond self-etching primer-treated enamel surface of human premolars using Superbond C&B. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours or after 2000 or 5000 cycles of thermocycling between 5 degrees C and 55 degrees C. Data were analyzed using 2-way analysis of variance and Fisher's protected least significant difference test for multiple comparisons. There was no significant difference in shear bond strength between phosphoric acid and Megabond self-etching primer treatment before the thermocycling test. After 2000 and 5000 thermal cycles, significant decreases in shear bond strength were observed with phosphoric acid etching. On the contrary, no significant differences in shear bond strength were observed after 2000 and 5000 thermal cycles with Megabond self-etching primer. The adhesive remnant indices were not significantly different between phosphoric acid etching and Megabond self-etching primer treatment either before or after thermal cycles. This study suggested that when used with Superbond C&B in bonding orthodontic brackets, Megabond self-etching primer is superior to phosphoric acid as an enamel preparation agent in providing durable bond strength.     

Ten-year observation of dentin bonding durability of 4-META/MMA-TBB resin cement--a SEM and TEM study

This study aimed to assess dentin bond durability of 4-META/MMA-TBB resin cement over ten years, by evaluating the tensile bond strength, and SEM and TEM observations. Tensile bond strength of Super Bond C&B (SB) to bovine dentin was evaluated at 1 day and after 10 years. The mode of failure after debonding was observed by SEM. Interfacial ultrastructure and nanoleakage was observed by TEM at the baseline and after 10 y. The tensile bond strength significantly dropped after 10 y. The failure pattern shifted from cohesive failure in resin towards adhesive failure or cohesive failure in dentin. TEM observation revealed degradation of both resin and collagen networks within the hybrid layer and nanoleakage at the base of the hybrid layer after 10 y. The bond strength of SB to dentin significantly decreased, and the hybrid layer degraded, while the overlying hydrophobic resin layer showed little disintegration over 10 y.     

Long-term sealing ability of Resilon apical root-end fillings

Aim  To evaluate ex vivo the long-term sealing ability of the SE Resilon Epiphany system as an apical root-end filling material.
Methodology  A total of 60 standardized horizontal bovine root sections were divided into three groups filled with either gutta-percha with AH 26, tooth-coloured mineral trioxide aggregate (MTA) or Resilon pellets with Epiphany SE, and submitted to capillary flow porometry at 48 h, 1 and 6 months to assess the minimum, mean flow and maximum pore diameters. Results of the different materials and results by material and time were analysed statistically using nonparametric tests; the level of significance was set at 0.05.
Results  Resilon had smaller pore diameters than gutta-percha and MTA at 48 h and smaller mean flow and maximum pore diameters than gutta-percha and MTA at 1 month. At 6 months Resilon had larger minimum pore diameters than gutta-percha. Although not always statistically significant, the minimum, mean flow and maximum pore diameters of gutta-percha and MTA diminished with time. This was not the case for Resilon, where the same parameters increased.
Conclusions  All materials leaked at all times. Resilon performed better than gutta-percha and MTA in the short-term, but the seal of MTA and gutta-percha improved over time whereas the seal of Resilon deteriorated. It is critical to evaluate the performance of materials in the long-term contrary to most studies which are short-term.     

Bonding durability between orthodontic brackets and human enamel treated with megabond self-etching primer using 4-META/MMA-TBB resin cement

The purpose of this study was to determine the bonding durability when a Megabond self-etching primer is used with 4-META/MMA-TBB resin to bond metal orthodontic brackets to human premolar enamel. Three conditions of enamel were prepared: Megabond self-etching primer without saliva contamination, Megabond self-etching primer with saliva contamination, and repeat Megabond self-etching priming after saliva contamination. Shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours, or after 2000 or 5000 cycles of thermal cycling between 5 degrees C and 55 degrees C. There were no significant differences in shear bond strength among the three groups not only before thermal cycling, but also after thermal cycling. FE-SEM observation revealed the presence of saliva and reduced amount of resin tag formation after saliva contamination. The present study provided the evidence in human teeth that when using 4-META/MMA-TBB resin, Megabond self-etching primer treatment produced tight bonding even when surface was contaminated with saliva.     

树脂粘接法固定牙周松动下前牙的临床观察

[摘要] 目的 观察用4-META/MMA-TBB树脂固定因牙周炎松动下前牙的临床疗效。方法 对56例经过牙周基础治疗,牙周炎得到控制,下前牙松动达Ⅱ°以上的患者,用4-META/MMA-TBB树脂在牙齿邻面直接粘接固定,定期观察2年,记录牙周检查指数并对患牙牙周临床检查效果及粘接固定效果进行评价。结果 4-META/MMA-TBB树脂固定牙周炎所致松动下前牙3、12、24个月后,患牙的牙龈出血指数、探诊深度、附着丧失显著降低(P<0.05);固定2年牙周临床检查有效率为92.9%,粘接固定有效率为89.3%。结论 4-META/MMA-TBB树脂粘接固定牙周炎所致的松动下前牙2年,对患牙牙周状况的改善效果显著且粘接效果稳定。     

Durability of adhesion between 4-META/MMA-TBB resin and cementum

4-META/MMA-TBB resin has shown good biocompatibility and remarkable adhesion to dentin. It seems to be suitable for use in periodontal tissues for retrograde root sealing and treatment of vertically fractured roots. For an adhesive resin to be useful clinically, it must bond not only to the dentin but also to the cementum. The purpose of this study was to evaluate the long-term adhesion durability of 4-META/MMA-TBB resin to cementum kept in water at 37 degrees C. Bovine root cementum and dentin surfaces were treated with 10-3 solution before 4-META/MMA-TBB resin was applied on treated surfaces. The micro-tensile bond strength (microTBS) decreased during the first two months; dye leakage value increased during the first four months and stabilized thereafter. No significant differences in adhesion durability were recognized between the dentin and cementum.     

树脂直接粘接法固定牙周松动前牙的二年效果观察

目的观察牙周炎松动前牙在用树脂直接粘接法固定治疗后二年的临床效果。方法牙周基础治疗后的12例牙周炎患者共计20颗Ⅱ～Ⅲ度松动前牙，采用4-META／MMA—TBB树脂在牙齿邻面将松牙直接粘接固定，定期观察，2年时对粘接固定治疗效果进行评价。观察粘接有无松脱，惠牙动度、探诊深度、附着丧失及牙槽骨高度的变化，用患者自我评分方法评价咀嚼功能的改善和对美观及舒适度的影响。结果18颗牙在二年中无松脱，20个月时2颗拥挤牙咬硬物后粘接松脱，已行再固定。二年时患牙的探诊深度、附着丧失较固定前有所改善（均值分别减少0．57mm、0．47mm，P〈0．05）；牙槽骨高度占根长的百分比与固定前相比平均增加7．04％（P〈0．05）；咀嚼功能评分从固定前的2．92±1．38分升至8．75±1．22分（P〈0．05），患者对临床美学效果满意，自觉舒适无异物感。结论采用4-META／MMA—TBB树脂直接粘接法固定牙周炎所致松动前牙，具有关观、舒适的特点，二年时粘接效果稳定，牙周状况改善，有助于改善牙齿的咀嚼功能。     

Adhesive bonding of titanium with a titanate coupler and 4-META/MMA-TBB opaque resin

Adhesive bonding of titanium was evaluated with a titanate primer and adhesive opaque resin. The primer consisted of 2% isopropyl dimethacryloyl isostearoyl titanate in methyl methacrylate. The adhesive was 4-META/MMA-TBB opaque resin that contained 4-methacryloyloxyethyl trimellitate anhydride and was initiated by tri-n-butylborane derivative. Titanium discs were machined and blasted with aluminum oxide. They were primed and bonded together with the opaque resin. A shear test was performed after repeated thermocycles for investigation of the durability of the bond. The shear strength of the primed and 4-META resin-bonded specimens was 37.2 MPa after 50,000 thermocycles, with only a small decrease in bond strength. This was significantly higher than the control values. Thus, titanate primer and 4-META/MMA-TBB opaque resin may be used for the bonding of titanium in prosthodontic practice.     

Effects of exposure to 4-META/MMA-TBB resin on pulp cell viability

Adhesive restorative systems have expanded the range of possibilities for direct pulp-capping technique, with evidences of clinical success in vital pulp therapy. However, quite few studies have described the direct responses of pulp cells following the application of resinous materials to pulp exposure. To address this issue, effects of exposure to an adhesive resin, 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butyl borane (4-META/MMA-TBB) resin on cellular activity were investigated in an established rat dental pulp cell line (RPC-C2A). RPC-C2A cells were cultured on normal plastic plates or the disks prepared from 4-META/MMA-TBB resin (Super Bond C&B) in a-MEM containing 10% FBS. After 3, 7 and 14 days, DNA content and alkaline phosphatase (ALP) activity were measured. Total RNA in each group was extracted and RT-PCR analysis was performed. Moreover, the live cell ratio was also evaluated by cytotoxicity assay after treatment with various concentrations of 4-META/MMA-TBB. At day 3, 7 and 14, amount of DNA and ALP activity of the cells on normal plastic plates and the one on the 4-META/MMA-TBB were comparable. Cells of both groups expressed mRNA of type I collagen (Coll), ALP, osteopontin (OPN), osteocalcin (OC), and bone morphogenetic protein (BMP-2). Furthermore, 4-META/MMA-TBB (10(-1)% or less) did not influence dead cell ratio in the confluent state. According to the results of these in vitro studies, exposure to this resinous material would not induce cytotoxic response in the pulp cells.     

Adhesion of 4-META/MMA-TBB resin to collagen-depleted dentin--effect of conditioner with ascorbic acid/ferric chloride

The purpose of this study was to evaluate ascorbic acid (AS) and ferric chloride (FE) for bonding 4-META/MMA-TBB resin to dentin that had been treated with NaClO. An experimental dentin conditioner consisting of 10%AS and 5%Fe (10AS-5FE) and three controls (10AS-0FE, 0AS-5FE, and 0AS-0FE) were prepared. Ascorcic acid neutralizes NaClO. The flattened dentin surfaces were modified sequentially with phosphoric acid etchant, NaClO agent, and the experimental conditioner, then each surface was bonded to a stainless steel rod with 4-META/MMA-TBB resin. The Super-Bond C&B (10-3/SB) system was also used. 24-hour tensile bond strengths were determined. The bonding system using 10AS-5FE conditioner showed significantly high bond strength compared to 10AS-0FE, 0AS-5FE, and 0AS-0FE. No significant differences were observed between 10AS-5FE and 10-3/SB. Microphotographs suggested that no hybrid layer formed in the 10AS-5FE group. Although the use of phosphoric acid and NaClO resulted in decreased bond strength between 4-META/MMA-TBB resin and dentin, additional conditioning with ascorbic acid and ferric chloride improved the bond strength.     

Adhesive 4-META/MMA-TBB opaque resin with poly(methyl methacrylate)-coated titanium dioxide

An adhesive opaque resin for veneering on cast metal was developed with 4-methacryloxyethyl trimellitate anhydride and poly (methyl methacrylate)-coated titanium dioxide prepared by aqueous phase polymerization. The opaque resin was a modified 4-META/MMA-TBB resin. The powder consisted of 20% of the encapsulated material and 80% PMMA instead of pure PMMA powder. This resin hides the metal color when the thickness of the resin is as thin as 50 microns. The opaque resin bonded strongly to both cobalt-chromium alloy and visible-light-cured veneering resin. This self-curing opaque resin is applicable not only for bonding veneering resin to an alloy surface but also for bonding fixed partial dentures to enamel surfaces.     

Influence of ascorbic acid on bonding of peroxide-affected dentin and 4-META/MMA-TBB resin

The purpose of this study was to evaluate the tensile bond strength (TBS) to peroxide-exposed dentin. Furthermore, the effect of ascorbic acid (AA) on the bond strength of peroxide-exposed dentin was investigated. Extracted bovine dentin was exposed to 10% carbamide peroxide, 30% hydrogen peroxide, or distilled water for 30 min, then treated with 10% AA (0, 30, 90, and 180 min), and conditioned with 10% citric acid/3% ferric chloride. The polymethyl-methacrylate (PMMA) rod was bonded to the treated bovine dentin with 4-META/MMA-TBB resin. A minidumbbell-shaped bonded specimen was prepared from these bonded assemblies and the TBS was tested. The fractured surfaces were also observed with a scanning electron microscope. Exposure to peroxide before bonding significantly reduced bond strength. The application of AA to the peroxide-exposed dentin increased bond strength. On the other hand, an adverse effect of AA was found in distilled water-affected dentin. Extended resin fibers were partially seen in the peroxide-exposed dentin. In conclusion, peroxide reduced the bond strength, and the stronger the oxidation, the weaker the obtained bond. Antioxidation with AA recovered the bond strength, and this effect increased the longer the AA was applied.K. Yazaki was formerly affiliated with Department of Pharmacology, Tokyo Dental College, 1-2-2, Masago, Mihama-ku, Chiba 261-8502, Japan. He is now in private practice.     

Dentin adhesion of "modified" 4-META/MMA-TBB resin: function of HEMA.

This study investigated adhesion to dentin of a modified 4-META/MMA-TBB resin (4-methacryloxyethyl trimellitate anhydride in methyl methacrylate initiated by tri-n-butyl borane) which does not require PMMA powder to polymerize. Ground bovine dentin specimens were pre-treated with an aqueous solution of 10% citric acid and 3% ferric chloride (10-3). This solution removes the smear layer and demineralizes the dentin, exposing collagen. Improved bond strengths were obtained when a HEMA-primer was applied to 10-3 pre-treated dentin. SEM examination revealed the formation of a transitional zone of resin-reinforced-dentin (hybrid layer) in 10-3 pre-treated, HEMA-primed samples. The adhesive monomer impregnated exposed collagen fibrils and, upon polymerization, became entangled with them to create the hybrid layer, essential in achieving significantly high tensile bonding strengths. HEMA enhanced the penetration capability of dentinal substrates. After polymerization and formation of the hybrid layer, auto-cured acrylic resin, photo-cured composite and amalgam were all capable of adhering to the dentin. The modified 4-META/MMA-TBB resin created significant adhesive bonds to 10-3 pre-treated ground bovine dentin.     

Influence of molecular weight of PMMA in PMMA/MMA-TBB resin on durability of adhesion to titanium against thermal stress in water

The present study examined the effect of the molecular weight of poly(methyl methacrylate) (PMMA) used in PMMA/ MMA-tributylborane (TBB) resin cement on the durability of adhesion to titanium against repeated thermal stress in water. PMMA beads with the same diameter and molecular weights of 1427, 239, 116, 78, and 66 (x 10(3)) were used. Titanium disks bonded to stainless steel or acrylic rods with the PMMA/MMA-TBB resin were subjected to a thermal cycling test (500 and 2,000 cycles) in water followed by tensile testing. Change in molecular weight of the resin cements collected after thermocycling and tensile testing was examined using size exclusion chromatography (SEC). The acrylic specimens exhibited a significant decrease in post-thermocycling bond strength as compared to the stainless steel specimens. It was also found that the molecular weight of PMMA powder in PMMA/MMA-TBB resin had little influence on adhesion durability to titanium. In terms of the molecular weight of resin cements, they decreased and then increased after 500 and 2,000 cycles respectively.     

Long-term tensile bond durability of two different 4-META containing resin cements to dentin.

OBJECTIVES: This study was conducted to evaluate the tensile bond durability of two different types of 4-META containing resin cements over a period of 3 years. METHODS: Ten bovine dentin specimens were tested for tensile bond strengths with each of the following materials: Super Bond C&B: unfilled methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) resin cement, MASA Bond (experimental material): filled dimethacrylate resin cement at 1 day, 6 months, 1 and 3 years. The mean bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test (P<0.05). The mode of failure was classified by SEM observation. Results for the mode of fracture were analyzed using the Mann-Whitney U test. RESULTS: Although there was no statistical difference in mean bond strength between Super Bond C&B and MASA Bond (P>0.05) during the experimental periods, the 1-day bond strengths were significantly greater than those at the other experimental periods except for 6 months (P<0.05). Regarding the fracture modes, at 6 months and 1 year, statistical differences were observed between Super Bond C&B and MASA Bond (P<0.05). SIGNIFICANCE: The bond strengths of both resin cements to dentin significantly decreased after 6 months, and the long-term failure patterns of the 4-META/TBB resin cements showed a marked change.