CIII بررسي اثر آمالگام باند بر استحكام اتصال آمالگام جديد به آمالگام قديمي در ترميم حفرات

Fracture strength of repaired cI II amalgam filling with amalgam Lending system (Research)

The repair of an existing amalgam restoration and the addition of fresh amalgam can be a very practical alternative to the removal of the entire restoration. In such cases, in order to achieve clinically acceptable results, strong bonding strength between fresh and aged amalgam of high importance. Several factors influence this bonding such as type of amalgam, type of cavity preparation, time and the use of bonding systems. The purpose of this study was not only to evaluate the strength of 2 Iranian made amalgams (Cinalux, Cinamix), but also to determine the fracture streng th of the fresh to aged amalgam bonding. Standardized class II preparations (Mo or Do) were placed in 120 teeth. Specimens were divided into 6 groups as follows: Group 1: Specimens were filled with spherical amalgam. (Cinalux). Group 2: Specimens were filled with admixed amalgam (Cinamix). Group 3: Specimens were filled with spherical amalgam, after 1 hour Proximal part of filling was completely removed and freshly triturated spherical amalgam was condensed against the surface to be repaired. Group 4: The same as Group 3, but in this group mixed amalgam was used. Group 5: After 1 hour, proximal part of filling was completely removed and alloy bond was brushed on the amalgam surface to be repaired and filling was completed with spherical amalgam. Group 6: The same as Group 5, but in this group, mixed amalgam was sued. In each group, half of the specimens 48 hours and the other half 30 days after repair were stressed under compression load until fracture occurred. The fracture strength was measured by kruska wallis and Mann-Whitney U statistical tests. No statistically significant difference was found between different types of amalgam (spherical, admixed) in the fracture strength of repaired CLII amalgam fillings (P>0.05). In addition, the use of amalgam bonding was not a significant factor (P>0.05). No statistically significant differences were observed in keeping samples in distilled water (2 days vs. 30 days). However, the results indicated considerable decrease in fracture strength after 30 days in all groups. Teh results of kruskal-wallis test also showed no with spherical amalgam after 48 hours (P=0.32) and groups repaired with mixed amalgam (P=0.51). The same results were found after 30 days for spherical amalgam (P=0.6) and mixed amalgam (P=0.33). The Following conclusions can be drawn from this study: 1 - Fracture strength of repaired (with or without amalgam bonding) c1II amalgam filings is comparable to unrepaire fillings. 2 - Type of amalgam is not a significant factor in the repair strength of amalgam filling. 3 - After 30 days, fracture strength of repaired filling may decrease comparing to that of after 2 days.