The influence of two chelating agents used in two different working times on the microleakage of packable composite resin used in post space : in vitro study

الملخص EN

Background : weakened teeth are not strengthened by the placement of a post but retention of restoration is enhanced by using a post.

Restoration with adhesive materials offers many advantages over the use of traditional materials, like transmission of functional stresses across the bonded interface to the peridontium, with potential to reinforce the weakened tooth structure.

Cavity preparation and root canal instrumentation leave a layer of debris that covers the walls of the cavity and root canal, known as smear which can be removed with a chelating agent.

This in vitro study conducted to evaluate the effect of two different chelating agents used in two different times of application on the microleakage of packable composite resin (Filtek P60 shade) used in post space.

Materials and method: Fifty, human, freshly-extracted mandibular premolars were selected.

After crown sectioning and conventional endodontic treatment, parallel post spaces 5mm in depth and 2mm in diameter were prepared using pesso burs (LARGO No.6).

Then the specimens were randomly divided into five groups as follow : Group1 (control) : the post space was filled with packable composite without previous using of chelating agent.

Group2 (experimental) : the post space was flooded with 17 % EDTA for 5 minutes prior filling with packable composite.

Group3 (experimental) : the post space was flooded with 10% citric acid for 5 minutes prior filling with packable composite.

Group4 (experimental) : The post space was flooded with 17 % EDTA for 10 minutes prior filling with packable composite.

Group5 (experimental) : The post space was flooded with 10 % citric acid for 10 minutes prior filling with packable composite.

After thermocycling and immersion in methylene blue, the teeth were sectioned\ longitudinally and dye penetration was evaluated using a stereomicrscope, micro leakage was recorded in mm.

Results : ANOVA test and least significant difference (LSD) test were used to analyze the results and to show the difference between groups.

Results expressed statistically highly significant reduction in micro leakage value among all groups ; with the lowest mean micro leakage value was in group5 in which citric acid was used for 10 min., followed by group4 in which EDTA was used for 10 min., followed by group3 in which citric acid was used for 5 min., followed by group2 in which EDTA was used for 5 min., and control group showed the highest micro leakage value.

Conclusion : from the results of the present study, it is clear that the application of a chelating agent prior using acid etch and adhesive system with composite resin filling material will significantly reduce micro leakage value of the restorative material.