أثر تخفيض الإطباق في الألم التالي للمعالجة اللبية للأسنان الخلفية

الملخص EN

Background and Objective: the remaining moisture after tooth structure etching differs according to drying technique and plays an important role in the bonding quality to tooth structure The aim of this study was to evaluate the effect of remaining moisture after phosphoric acid etching on gingival and occlusal microleakage of class five composite restorations.

Methods and Materials: 30 class five cavities (3X3X2 mm) were prepared on the facial surfaces of freshly extracted human upper premolars with gingival walls 0.5 mm beneath cemento-enamel junction.

After etching with 37% phosphoric acid for 15 second and rinsing with water, cavities were divided randomly into three groups (n=10) according to drying protocols: 1- cavities were dried with continues air drying for 5 seconds (group 1), 2- cavities were dried like in group 1 and only the dentinal surfaces were rehydrated with small applicator (group 2), 3- cavities were left moist by removing the water excess with small cotton pellet without any air drying.

Single Bond 2 (3MESPE) was applied then in two coats and polymerized for 10 seconds.

After that, cavities in all groups were restored with Z250 XT (3MESPE) composite in three layers and each was polymerized for 20 seconds.

After 150 thermocycles and teeth isolation with nail polish until 1 mm restoration surroundings, teeth were immersed in 0.5% methylene blue for 24 hours and dye penetration was evaluated on gingival and occlusal walls after facio-lingual sections.

Data were analyzed using Kruskal Wallis and Mann-Whitney statistical tests using SPSS 13 edition with P value of 0.05.

Results: there were significant statistical differences in gingival wall microleakage between the three groups P<0.05.

But on contrary, no statistical significant differences were detected in occlusal wall microleakage between three groups as well as between gingival and occlusalmicroleakage P>0.05.

Conclusions: 1- Different cavity drying protocols did not affect class five occlusal wall microleakage.

2-Microleakage was less when drying etched cavity for 5 seconds compared with moist left etched cavity surfaces.

3- Occlusal microleakage was less than gingival microleakage with no statistical differences.