|
| ||
|
|
||
Bond Failure (bond + failure)
Selected AbstractsEffect of Net Fiber Reinforcement Surface Treatment on Soft Denture Liner Retention and LongevityJOURNAL OF PROSTHODONTICS, Issue 4 2010MPhil, Muhanad M. Hatamleh BSc Abstract Purpose: To evaluate shear bond strength of Molloplast-B soft liner attached to different acrylic surfaces (smooth, rough, and Sticktech net fiber-reinforced interfaces) after 3000 thermal cycles. Materials and Methods: Sixty-nine specimens were fabricated by attaching Molloplast-B soft liner to acrylic bases of three interfaces (n= 23); smooth (Group 1, control), rough (Group 2), and Sticktech net fiber-reinforced interface (Group 3). The specimens underwent 3000 thermocycles (5 and 55°C) before being subject to a shear bond test at 2 mm/min crosshead speed. Debonding sites were investigated using an optical microscope at 40× magnification. Bond failures were categorized as adhesive, cohesive, or mixed. Results: Mean (SD) bond strength values (MPa) were: 0.71 (0.15); 0.63 (0.07); and 0.83 (0.12) for smooth, rough, and fiber-reinforced acrylic interfaces, respectively. The mean values were analyzed using one-way ANOVA and Bonferroni post hoc test for pairwise comparisons (p, 0.05). The net fiber-reinforced acrylic interface exhibited a statistically significantly higher bond strength value when compared to smooth and rough acrylic interfaces (P= 0.003 and P= 0.000, respectively). Modes of failure were mainly cohesive (91%), followed by mixed failures (9%). Conclusions: Molloplast-B exhibited a stronger bond to StickTech Net fiber-reinforced surfaces when compared to smooth and rough acrylic interfaces after thermocycling. This may enhance prosthesis serviceability during clinical use. [source] Enamel microhardness and bond strengths of self-etching primer adhesivesEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2010Olabisi A. Adebayo Adebayo OA, Burrow MF, Tyas MJ, Adams GG, Collins ML. Enamel microhardness and bond strengths of self-etching primer adhesives. Eur J Oral Sci 2010; 118: 191,196. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci The aim of this study was to determine the relationship between enamel surface microhardness and microshear bond strength (,SBS). Buccal and lingual mid-coronal enamel sections were prepared from 22 permanent human molars and divided into two groups, each comprising the buccal and lingual enamel from 11 teeth, to analyze two self-etching primer adhesives (Clearfil SE Bond and Tokuyama Bond Force). One-half of each enamel surface was tested using the Vickers hardness test with 10 indentations at 1 N and a 15-s dwell time. A hybrid resin composite was bonded to the other half of the enamel surface with the adhesive system assigned to the group. After 24 h of water storage of specimens at 37º°C, the ,SBS test was carried out on a universal testing machine at a crosshead speed of 1 mm min,1 until bond failure occurred. The mean ,SBS was regressed on the mean Vickers hardness number (VHN) using a weighted regression analysis in order to explore the relationship between enamel hardness and ,SBS. The weights used were the inverse of the variance of the ,SBS means. Neither separate correlation analyses for each adhesive nor combined regression analyses showed a significant correlation between the VHN and the ,SBS. These results suggest that the ,SBS of the self-etch adhesive systems are not influenced by enamel surface microhardness. [source] Marginal gap formation of composites in dentine: effect of water storageJOURNAL OF ORAL REHABILITATION, Issue 3 2003A. U. J. Yap summary, This study investigated the effects of water storage on the marginal adaptation of two composite resins (Spectrum TPH and Ariston AT), two polyacid-modified composite resins (Dyract AP and F2000) and a new PRG composite (Reactmer) to dentine over time. Two cylindrical dentine cavities (1·5 mm diameter and 1·5 mm deep) were prepared on the horizontally sectioned surfaces of freshly extracted teeth. In each tooth, one cavity was restored using composites with their respective bonding system and the other without the bonding system. The sample size for each material with/without bonding system was 6. The composites were placed in one increment, bulk-polymerized, immediately finished/polished with the Sof-lex discs system and fine polished on 30 ,m silicon carbide/9 ,m aluminium oxide lapping film discs in a microgrinding system. The specimens were then stored in distilled water at 37 °C and the maximum marginal gap width between the material and the dentine wall was determined at 24 h, 1 week, 2 weeks, 3 weeks and 4 weeks using a measurescope at ×500 magnification. Results were subjected to statistical analysis using monva, anova/Scheffe's post hoc test and independent samples of t -test at significance level 0·05. At all time intervals, no significant difference in marginal gap formation was observed between materials. Where bonding systems were not used, a decrease in gap widths over time was observed with most materials but only Dyract AP exhibited a significant decrease. The latter was observed after 2 weeks storage in water. The use of bonding systems reduced dentine marginal gaps significantly and is therefore mandatory for all composites evaluated. Marginal gaps arising from polymerization contraction of conventional, polyacid-modified and PRG composites cannot be fully compensated by hydroscopic expansion. Clinical relevance Bonding systems are mandatory for all composites when bonding to dentin. In the event of a bond failure at placement, hygroscopic expansion of composites can reduce marginal gaps but not completely. [source] Effects of surface treatments on bond strength of glass-infiltrated ceramicJOURNAL OF ORAL REHABILITATION, Issue 9 2001Y.-C. Lu The purpose of this study was to evaluate the effects of various surface treatments on the bond strength at the In-Ceram/resin composite interface. Ninety-eight In-Ceram specimens were divided into seven groups and exposed to various surface treatments as follows: (A) control (B) saliva contamination (C) saliva contamination plus aluminum oxide sandblasting (D) glove powder contamination (E) glove powder contamination plus aluminum oxide sandblasting (F) rough aluminum oxide sandblasting and (G) excess glass infiltration. A resin composite cylinder was cemented to each In-Ceram specimen with Panavia 21 resin luting cement. Half of the cemented specimens in each group were stored in water for 24 h, and the other half were stored in water for 2 weeks and then were thermo-cycled for 2000 cycles. Shear bond strengths (SBS) of seven specimens in each subgroup were determined and analysed using analysis of variance (ANOVA) and Tukey HSD test as well as Student,s t -test. Scanning electronic microscopy was used to identify the type of bond failure. Shear bond strength was significantly decreased by saliva and glove powder contaminations (P < 0·05). Sandblasting treatment did not improve the saliva-contaminated specimens. However, the glove powder plus sandblasting group showed no significant difference in SBS compared with the control group. There was no significant difference in SBS between the excess glass-infiltrating group and the control group. The SBS was significantly decreased by rough aluminum oxide sandblasting (P < 0·05). The SBS values of groups without thermocycling were significantly greater than those of groups with thermocycling (P < 0·05). There were no significant differences among SBS values of the seven groups with thermocycling. Combined cohesive and adhesive bond failures were seen in every group. Various surface treatments or contaminants may significantly influence the bond strength of In-Ceram restorative in clinical use. [source] | ||||||||||