WITH DIFFERENT ACIDS AND ONE SELF PRIMING ADHESIVE
Abstract
Introduction. Because of advancements in dental restorative techniques and introduction of new materials, the patients demand for suitable restorations has been increased. Composite resin restorations are suitable restorations, because of conservative preparation and acceptable appearance. One of the basic stages of direct composite restoration is enamel acid etching to provide retention of restoration and eliminating microleakage.
Methods. Different studies, have recommended use of phosphoric acid (30-40%) for 15s and rinsing time of 15-20s. It seems that this method leads to acceptable enamel bond strength. In this study, the enamel shear bond strength of composite resins with use of Kimia, Pish-Ro and 3M acids was investigated. Also, the pattern of enamel etching by these acids was investigated under SEM observation. After collection of 33 intact canines and premolars, the buccal surfaces were grinded. The teeth were divided into 3 groups and then etched with different acids for 20s, then rinsed for 15s. 2 Coats of Single Bond adhesive resin were applied on the surface and cured for 10s. Z100 composite resin was applied on the surface with cylindrical molds and cured for 100s (5x20s). After thermocycling and mounting of samples, shear forces were applied on the restoration with Dartek instron and the data were analyzed by 1-way variance analysis, Kruskal-wallis test and Duncan"s test. For SEM observation 10 human maxillary central incisors were selected with no lesion. After cleaning and storage in 0.2% thymol, the teeth were divided into 2 groups. The labial surface of the teeth were polished and divided into two mesial and distal portins. Mesial portion of each specimen was treated with 3M acid and the distal portion was treated with Kimia acid. The first group was etched for 45s and the second group for 20s. After rinsing for 20s and drying for 20s, the etching patterns were observed under SEM observation.
Results. Mean shear bond strength of Kimia group was 24.57 MPa, 35.17MP a for Pish-Ro group and 36.93 MPa for 3M group. The difference of mean shear bond strength was not significant (P > 0.05) but the difference of failure mode was significant (P < 0.05, X2=16.3). It seems that the applied adhesive resin system is more important than type of phosphoric acid.
Discussion. The main enamel etching pattern was type II in the middle and inciasl portions and type III in the cervial areas. Also, some evident morphologic differences were observed. First, the etching patterns gained by standard acid were more even in comparison with Kimia acid. Another difference was the recognition of more deposits on the surfaces etched with Kimai acid. lastly, Image Analyzer showed higher percent of area fraction surfaces created with standard acid.
Methods. Different studies, have recommended use of phosphoric acid (30-40%) for 15s and rinsing time of 15-20s. It seems that this method leads to acceptable enamel bond strength. In this study, the enamel shear bond strength of composite resins with use of Kimia, Pish-Ro and 3M acids was investigated. Also, the pattern of enamel etching by these acids was investigated under SEM observation. After collection of 33 intact canines and premolars, the buccal surfaces were grinded. The teeth were divided into 3 groups and then etched with different acids for 20s, then rinsed for 15s. 2 Coats of Single Bond adhesive resin were applied on the surface and cured for 10s. Z100 composite resin was applied on the surface with cylindrical molds and cured for 100s (5x20s). After thermocycling and mounting of samples, shear forces were applied on the restoration with Dartek instron and the data were analyzed by 1-way variance analysis, Kruskal-wallis test and Duncan"s test. For SEM observation 10 human maxillary central incisors were selected with no lesion. After cleaning and storage in 0.2% thymol, the teeth were divided into 2 groups. The labial surface of the teeth were polished and divided into two mesial and distal portins. Mesial portion of each specimen was treated with 3M acid and the distal portion was treated with Kimia acid. The first group was etched for 45s and the second group for 20s. After rinsing for 20s and drying for 20s, the etching patterns were observed under SEM observation.
Results. Mean shear bond strength of Kimia group was 24.57 MPa, 35.17MP a for Pish-Ro group and 36.93 MPa for 3M group. The difference of mean shear bond strength was not significant (P > 0.05) but the difference of failure mode was significant (P < 0.05, X2=16.3). It seems that the applied adhesive resin system is more important than type of phosphoric acid.
Discussion. The main enamel etching pattern was type II in the middle and inciasl portions and type III in the cervial areas. Also, some evident morphologic differences were observed. First, the etching patterns gained by standard acid were more even in comparison with Kimia acid. Another difference was the recognition of more deposits on the surfaces etched with Kimai acid. lastly, Image Analyzer showed higher percent of area fraction surfaces created with standard acid.
Keywords
Acid Etching, Bond Strength, Composite Resin, Bonding Agent, Etching Pattern