Microleakage of two new dentinal bonding systems

Class V abrasion and erosion lesions restored with composite resin seem to be more susceptible to microleakage, because the gingival margin is usually placed in cementum and/or dentin. The purpose of this study was to evaluate the microleakage, in vitro, of two new dentinal bonding systems along with a positive and negative control. This study was accomplished using extracted human teeth and a calcium-45 radioisotope technique. The teeth were examined for microleakage at periods of 1 week, 6 months, and 1 year. The results at all time intervals indicated that the cavities restored with the new bonding agents and their respective composite resins leaked more than did the negative control, glass-ionomer cement.     

Microleakage of seven adhesive systems in enamel and dentin

AIM: The aim of this study was to evaluate the microleakage of seven adhesive systems on two substrates (enamel and dentin). METHODS AND MATERIALS: Class V cavities were performed in buccal and lingual surfaces of 56 bovine incisors. The cervical margin was located in dentin and the incisal margin in enamel. The specimens were randomly divided into seven groups (n=16), according to the adhesive system employed: Single Bond; Excite; One Step Plus; Gluma One Bond; Magic Bond; One Up Bond F; and One Coat Bond. The cavities were incrementally filled with a hybrid composite Filtek Z250 and polymerized with a XL 3000 light curing unit. After polishing, the specimens were submitted to thermal cycling followed by dye immersion. Leakage was evaluated under magnification (40X) based on a standard ranking. Data were subjected to statistical analysis (Kruskal-Wallis). RESULTS: Enamel margins exhibited lower leakage than dentin margins (p<0.01). The majority of the specimens were leakage-free and materials performed similarly. Conversely, in dentin most of the specimens exhibited the highest leakage degree and significant differences among materials (p<0.05) were found, with Excite exhibiting the lowest leakage degree. It was concluded enamel provided better sealing and the adhesive system was a significant factor only in dentin.     

Micro-shear bond strength of two all-in-one adhesive systems to unground fluorosed enamel

The aim of this study was to evaluate the micro-shear bond strengths of two all-in-one adhesive systems to unground fluorosed enamel. Buccal surfaces of 24 normal and 24 moderately fluorosed teeth (Thylstrup and Fejerskov index, TFI=4-6) were bonded using G-Bond and Clearfil Tri-S Bond. The surfaces were then restored with a resin composite, stored for 24 hours in water, and tested for micro-shear bond strength (MSBS). Fracture modes, etching patterns, and adhesive interfaces were studied under a scanning electron microscope (SEM). Data were analyzed with two-way ANOVA, whereby no significant differences in MSBS were found among the four groups (p>0.05). Through SEM examination, it was shown that 1 microm of resin tag-like extensions had penetrated into the enamel for both adhesives at the enamel-adhesive interface. Based on the results obtained, it was concluded that MSBS was not influenced by the severity of fluorosis. Furthermore, there were no differences in enamel bond strength between G-Bond and Clearfil Tri-S Bond.     

Microleakage of dentin adhesive systems

Five different dentin adhesives were evaluated under various experimental conditions (using different restorative materials, placement techniques, and specimen storage). A silver-staining technique was used to detect microleakage. Pentra Bond II was less effective than Tenure in prevention of marginal leakage, but similar to Scotchbond 2 and Gluma.     

Microleakage of two new combined primer/adhesive resin systems

In vitro microleakage of two new combined primer/adhesive systems utilizing the all etch technique (enamel and dentin etch) with the hybrid composite resin TPH is reported. These new combined primer/adhesive systems were compared to the Optibond FL system, which consists of a separate primer and adhesive. Forty Class V preparations were cut on the facial surfaces at the cemento-enamel junction of bovine incisor teeth to a dimension of 2.0 mm x 3.0 mm x 2.0 mm with a 1.0 mm 45 degree incisal bevel. The enamel (incisal) and dentin (gingival) margins were scored separately. Results suggest that Prime & Bond provided an improvement in the gingival marginal seal over the other materials. There was no statistically significant difference in the sealing ability of the materials tested at the incisal margin.     

Microleakage study of three adhesive systems

The purpose of this in vitro study was to evaluate the efficacy of three hydrophilic dentin adhesive systems to reduce class II restoration microleakage. A total of 60 human molar teeth were used in which two box cavities were made on the distal and mesial surfaces, with a cervical margin in dentin. These cavities were randomly divided into 3 groups (n = 40 each), according to adhesive system tested: G1: OptiBond SOLO(R); G2: Amalgambond Plus(R); G3: Etch & Prime 3.0(R). The cavities were restored with the composite resin Z-100(R). The groups were thermocycled 2000 times (5 +/- 1 masculineC and 55 +/- 1 masculineC) with a dwell time of 1 min. The teeth were then immersed in 2% methylene blue, pH 7.0, for 4 h, sectioned and observed with a stereomicroscope MEIJI 2000 (35X). The evaluation was made using scores (0-4) and the results were expressed through the sum of the ranks. G1 = 1994.00; G2 = 2294.00; G3 = 2972.00. The three groups were significantly different. The self-etching adhesive system Etch & Prime 3.0 was less effective in preventing microleakage. The OptiBond SOLO adhesive was the most effective in reducing microleakage in dentin margins when compared with Amalgambond Plus and Etch & Prime 3.0.     

Effect of functional monomers in all-in-one adhesive systems on formation of enamel/dentin acid-base resistant zone

This study aimed at evaluating the effect of functional monomers in all-in-one adhesive systems on formation of acid-base resistant zone (ABRZ) in enamel and dentin. Experimental adhesive systems containing one of three functional monomers; MDP, 3D-SR and 4-META were applied to enamel or dentin surface and light-cured. A universal resin composite was then placed. The specimens were subjected to a demineralizing solution (pH 4.5) and 5% NaClO for acid-base challenge and then observed by SEM. The ABRZ was clearly observed in both enamel and dentin interfaces. However, enamel ABRZ was thinner than dentin ABRZ in all adhesives. Morphology of the ABRZ was different between enamel and dentin, and also among the adhesives. Funnel-shaped erosion was observed only in the enamel specimen with the 4-META adhesive. The formation of enamel/dentin ABRZ was confirmed in all adhesives, but the morphology was influenced by the functional monomers.     

Microleakage and enamel finish.

Cavity preparations that are finished with hand instruments allow significantly less marginal leakage than those which are completed only with rotary instruments. This does not mean that hand-instruments walls are perfectly smooth; it only means that these walls allow less marginal leakage. Cavity preparations restored with composite resin showed more marginal leakage than those restored with amalgam. Also, the degree of marginal leakage was greater in cavity preparations restored with composite resin than in those restored with amalgam. Cavity preparations are more prone to marginal leakage at sharply defined cavosurface acute angles than at the smooth or straight surfaces of the cavity. This pattern of marginal leakage was true for both amalgam restorations and composite restorations, but the degree of marginal leakage was greater when composite resin was used as a restorative material. Since less marginal leakage was found in the finished cavity preparations, it is obvious that all cavity preparations must be finished with hand instruments. This may not completely eliminate the problem of marginal leakage, but it will reduce the potential secondary caries both in degree and frequency. Also, since sharply defined acute angles did exhibit more marginal leakage, this part of the cavity preparation needs special attention. With amalgam and composite restorations at least, these angles should not be sharply defined but should be slightly round, so that better condensation of restorative materials can be obtained. This may reduce the degree of marginal leakage.     

Microleakage of three dentinal bonding systems: a 6-month evaluation

This study evaluated the marginal sealing ability of three of the latest generation of dentinal bonding agents following 6 months of storage in a 37 degree C water bath. Class V preparations were placed at the cementoenamel junction of extracted human molars. Herculite XR was used to restore cavities that had been pretreated with Gluma, Tenure, or XR Bond. The restored teeth were thermally stressed every 30 days during the following 6 months, and then microleakage was assessed by dye penetration. Under the experimental conditions, the microleakage associated with XR Bond and Gluma was not statistically significantly different. XR Bond performed statistically significantly better than Tenure (a = 0.01).     

Biocompatibility of dentinal adhesive systems in conservative dentistry

Several studies have been published on "in vitro" and "in vivo" evaluations on pulpal and dentin effects of new dentinal bonding agents. The present study analyses the current status of biocompatibility of these materials. It has been suggested that a good biocompatibility it is only possible if no bacteria penetration and microleakage are present along dentinal walls and around restoration cavity. Finally it is not well defined the importance of smear layer removal from cut dentin surface.     

Influence of dentinal regions on bond strengths of different adhesive systems

This in vitro study assessed comparatively the shear bond strengths of three composite resins, 3M Valux Plus (3MVP), Herculite (H), Clearfil AP-X (CAP-X), a polyacid modified composite resin Dyract (D), and a resin modified glass-ionomer materials Vitremer (V), to cervical and buccal dentine regions of extracted human molar teeth. Four different bonding systems, 3M ScotchBond Multipurpose (SB), Clearfil Liner Bond 2 (LB2), Opti Bond (OB), and Prime & Bond 2.1 (PB 2.1) were used with the manufacturer's respective composite and compomer materials. One hundred freshly extracted mandibular molar teeth were selected for this study. Flat buccal dentine surfaces were created on 50 teeth and cylindrical rods of the five materials were bonded to the dentine surfaces. For assessment of cervical bond strengths, the materials were bonded to mesial and distal enamel bordered occlusal dentinal surfaces of the remaining 50 teeth. The five groups of restorative procedures were applied as follows; Group 1: SB + 3MVP, Group 2: LB2 + CAP-X, Group 3: OB + H, Group 4: PB2.1 + D, Group 5: Vitremer primer (VP) VP + V. Each restorative procedure thus had 20 specimens (10 buccal + 10 cervical). After 24 h of water storage (37 degrees C), the specimens were tested on a Universal Testing machine in shear with a cross head speed of 0.5 mm min-1. The bond strength values were calculated in MPa and the results were evaluated statistically using Kruskal-Wallis one-way/anova and Mann-Whitney U-tests. It was found that the bond strengths of SB + 3MVP, LB2 + CAP-X and VP + V to buccal dentine surfaces were significantly stronger (P < 0.05) than those to the occluso-cervical dentine floors. When the bond strengths to the occluso-cervical dentine and buccal dentine surface were compared, there was no significant difference between the materials (P > 0.05). Vitremer was found the least successful adhesive material in terms of shear bond strength on both buccal and occluso-cervical dentine surfaces.     

Bonding to enamel and dentin using self-etching adhesive systems.

OBJECTIVES: This study investigated the effectiveness of three different dentin adhesive systems on the adhesion of resin composite to both dentin and enamel. METHOD AND MATERIALS: The flat dentin and enamel surfaces of 60 extracted human molar teeth were exposed by wet grinding with 600-grit silicon carbide paper. One total-etch self-priming adhesive system (Prime & Bond NT), one two-step self-etching primer adhesive system (Clearfil SE Bond), and one "all-in-one" self-etching adhesive system (Prompt L-Pop) were evaluated. Each bonding system was applied according to the manufacturer's instructions and followed by composite (TPH Spectrum) application. Twenty-four hours after bonding, the teeth were subjected to shear testing. There were 10 replicates for each group. RESULTS: Prompt L-Pop exhibited significantly higher bond strength values to enamel (27 +/- 4.2 MPa) than all other groups. There were no statistically significant differences for shear bond strength to dentin among adhesives. Prompt L-Pop showed the statistically significantly higher bond strength to enamel than dentin. There were no statistically significant differences between the enamel and dentin bond strengths of Clearfil SE Bond and Prime & Bond NT. CONCLUSIONS: The self-etching adhesive systems produced high bond strengths to human coronal dentin and ground enamel surfaces. These materials seem to be very promising for further clinical applications, and the results are very encouraging for the clinical success of these simplified adhesive systems. The self-etching adhesive systems produced even better bond strengths to both enamel and dentin than conventional total-etch systems, especially the "all-in-one" system, which produced the highest bond strength to enamel.     

Microleakage of adhesive resin systems in the primary and permanent dentitions

PURPOSE: The purpose of this study was to compare the in vitro microleakage of fourth-generation filled and unfilled adhesive resin systems with fifth-generation filled and unfilled adhesive resin systems in both primary and permanent teeth. METHODS: Eighty extracted or exfoliated human noncarious teeth (40 primary and 40 permanent) were assigned to each of 8 groups. Groups 1, 3, 5 and 7 were primary teeth, and groups 2, 4, 6 and 8 contained permanent teeth. Groups 1 and 2 were bonded with Optibond Fl (Kerr), groups 3 and 4 with Scotchbond Multipurpose (3M), groups 5 and 6 with Optibond Solo Plus (Kerr) and groups 7 and 8 with Single Bond (3M). All teeth received a Class V cavity preparation, and the cavosurface margins were placed entirely in enamel. They were then restored with TPH Spectrum Shade Al (Dentsply Caulk). All teeth were thermocycled, stained with basic fuchsin, sectioned and viewed under the microscope. Measurements were recorded in absolute millimeters and relative grades as judged by 2 evaluators. RESULTS: No significant difference in microleakage was observed between fourth- and fifth-generation adhesive resin systems, whether filled or unfilled, or applied on primary or permanent teeth. Significant differences were found in the amount of microleakage at the gingival and occlusal surfaces in all groups. One-bottle, fifth-generation adhesive resin systems permit easier application with the same effectives as the 2-bottle, fourth-generation systems. CONCLUSIONS: One-bottle, fifth-generation adhesive resin systems permit easier application with the same effectiveness as the 2-bottle, fourth-gerenration systems.     

三种牙本质粘接剂修复V类洞的微漏研究

目的 评价三种牙本质粘接剂对v类洞边缘的封闭效果。方法 30颗新拔除的正常双尖牙随机分为三组（n=10），在颊侧颈部釉牙骨质界处制备标准的v类洞（溶2mm、宽3mm）。三种粘接系统：Scotchbond Multi-Purpose，Adper PromptL-Pop，Contax和相应的修复树脂修复V类洞缺损并成形和抛光后，在37℃水中存放一周，然后进行300个冷热循环（5／55℃），最后将牙齿浸泡在296的甲基兰溶液中（37℃）24小时，将所有牙齿沿颊舌向切成两半，立体显微镜观察边缘微漏的染色情况，记录评分结果。数据进行Kruskal-WallisTest检验。结果 三种粘结剂在v类洞的釉质均没有微漏发生，AdperPromptL-Pop牙本质边缘的微涌评分结果较ScotchbondMulti—Purpose差，差异有显著性（P〈0．05），其它两组间无显著性差异。釉质边缘的整体评分明显优于牙本质边缘。结论 三种粘接系统对釉质边缘的封闭效果相对更稳定；釉牙骨质界下方的特殊预备体边缘结构可能造成边缘封闭效果不良。     

NaOCl degradation of a HEMA-free all-in-one adhesive bonded to enamel and dentin following two air-blowing techniques

OBJECTIVE: Phase-separation within HEMA-free all-in-one dental adhesives may result in the entrapment of droplets within the adhesive resin. Strongly air-blowing prior to polymerization, can remove most of these droplets. The objective of this study was to evaluate the effect these droplets may have on the resistance of the adhesive-tooth interface to NaOCl degradation. METHODS: The micro-tensile bond strength (microTBS) to enamel and dentin was determined when a HEMA-free all-in-one adhesive was applied either following a mild or strong air-blowing technique. The bonds were also exposed to an aqueous sodium hypochlorite (NaOCl) solution for 1h, following a recently introduced methodology to mimic in vivo bond degradation. RESULTS: This study revealed that strong air-blowing of the adhesive only resulted in a significantly higher micro-tensile bond strength (microTBS) to dentin, but not to enamel. Likewise, NaOCl only reduced the microTBS to dentin for both the mild and strong air-blowing technique, but again not the microTBS to enamel. Failure analysis by SEM clearly revealed that strong air-blowing is less effective in droplet removal when the adhesive was applied in small and narrow class-I cavities, as compared to when it was applied to flat surfaces. CONCLUSIONS: NaOCl did preferentially dissolve the hybrid layer at dentin, and more for the mild than for the strong air-blowing technique. A strong air-blowing procedure resulted in a more NaOCl-resistant hybrid layer, so that it can be concluded that a HEMA-free one-step adhesive definitely benefits from a strong air-blowing technique.     

Effect of dentinal surface preparation on bond strength of self-etching adhesive systems

The aim of this study was to evaluate the effects of dentin surface treatments on the tensile bond strength (TBS) of the self-etching primer Clearfil SE Bond (CSE) and the one-step self-etching One-Up Bond F (OUB). The exposed flat dentin surfaces of twenty-four sound third molars were prepared with diamond bur at high-speed, carbide bur at low-speed or wet ground with #600 grit SiC paper. The adhesive systems were applied to the dentin surfaces and light-cured according to the manufacturers' instructions. A 6-mm high composite crown was incrementally built-up and each increment was light-cured for 40 seconds. After being stored in water (37 degrees C/24 h), the samples were serially sectioned parallel to the long axis, forming beams (n = 20) with a cross-sectional area of approximately 0.8 mm(2). The specimens were tested in a Universal Testing Machine at 0.5 mm/min. The cross-sectional area was measured and the results (MPa) were analyzed by two-way ANOVA and Tukey Test (p < 0.05). Overall, the groups treated with CSE exhibited the highest TBS for all surface treatments. Dentin surfaces prepared with carbide bur at low speed reduced TBS in the CSE group; however, OUB was not affected by surface treatments. The effect of surface abrasive methods on TBS was material-dependent.     

Microleakage and SEM interfacial micromorphology of amalgam restorations using three adhesive systems

OBJECTIVE: This study evaluated the microleakage and interfacial micromorphology of Class V cervical amalgam restorations lined with OptiBond, AElitebond, or Panavia 21. METHODS: Unlined amalgams served as control. Cavities were treated with each dentin bonding system according to the manufacturers' instructions and restored with Tytin non-gamma 2 spherical amalgam. After one week of storage in tap water at 37 degrees C, the specimens were thermocycled (1000 cycles, 6-60 degrees C, 30s dwell time). Microleakage was assessed by means of basic fuchsin dye penetration and recorded according to an ordinal scale. RESULTS: None of the systems tested in this study completely eliminated microleakage. Kruskal-Wallis one-way ANOVA and Mann-Whitney U test found that on the occlusal wall, Panavia 21 and the control group had the least leakage (P<0.05). No statistically significant differences were found at dentin margins (P>0.05). Wilcoxon matched pairs signed rank test found that Panavia 21 and the control group had less leakage at the occlusal than at the dentin margins (P<0.05); when AElitebond and OptiBond groups were evaluated, microleakage at the enamel and at the dentin margins was similar for each group. With the adhesive systems, perhaps the hydrophilic bonding agents incorporated the dye during specimen immersion and/or sectioning. CONCLUSIONS: The use of adhesives may not be as worthy as resin cements for sealing and bonding amalgam restorations to enamel and dentin.     

Fatigue testing of enamel bonds with self-etch and total-etch adhesive systems.

OBJECTIVE: Etching of enamel by self-etching adhesive systems is not as pronounced as with phosphoric acid employed with most total-etch adhesive systems. This may result in differences in the effectiveness of the bonds for the two types of systems. The aim of this study was to compare two such systems by bond strength and fatigue testing. MATERIALS AND METHODS: Shear bond strengths for Single Bond (SB) and Adper Prompt-L-Pop (PLP) were obtained on bovine enamel surfaces. Fatigue measurements were made with the same test fixtures using cyclical loading at 2 Hz for a maximum of 10(5) cycles or until the bond failed. Four selected loads between 40 and 70% of the shear bond strength were tested for each adhesive and the number of cycles to failure was recorded. S-N curves were constructed from the data and fatigue stress limits were determined. The Mann-Whitney U-test and t-tests were used for statistical comparisons of the results. SEM analysis of resin tag formation into enamel surfaces was carried out. RESULTS: A significantly greater bond strength was found for SB (25.3 MPa) than for PLP (19.2). Sustainable stresses after 10(5) load cycles were substantially lower than the corresponding shear bond strengths and fatigue limits were found to be 8.4 MPa for PLP and 14.6 MPa for SB. The ratio of fatigue limit to bond strength was less for PLP (44%) than for SB (57%). Resin tag penetration into enamel was substantially less for PLP than for SB. SIGNIFICANCE: Fatigue testing in conjunction with bond strength testing can provide a better means for assessing the performance of adhesive systems used for bonding to enamel.