An In-vitro Evaluation of the pH Change Through Root Dentin Using Different Calcium Hydroxide Preparations as an Intracanal Medicament.

Context: The aim of the study was to evaluate the pH variation in the surrounding medium after the use of two different vehicles of Calcium hydroxide - Saline (aqueous), Propylene glycol (viscous) and Calcium hydroxide containing guttapercha points over a period of 7 days as an intracanal medicament.

Materials And Methods: Sixty single rooted premolars were decoronated at the cementoenamel junction and cleaned and shaped uptil size 40 master apical file. External defects were made on the mesial surface in the coronal third of the roots and divided randomly into 4 groups. One control and three experimental. In the control - group I the root canals were left empty. In the experimental groups - group II was filled with Ca(OH)2 + saline, group III was filled with Ca(OH)2 + propylene glycol and group IV the root canals were filled with Calcium hydroxide points. The coronal accesses were sealed with 3mm of Cavit G and all the surfaces of the root except the defect were covered with 3 coats at Nail varnish. The samples were then placed in air tight vials containing 2ml of distilled water. The vials were kept in an incubator and the pH of the surrounding medium was measured using a digital pH meter after 1,3,5 and 7 days respectively.

Results: A statistically significant difference (p<0.05) existed between the experimental groups over the observation period. At day 1, a high pH was recorded by the calcium hydroxide points and saline groups and a lower pH by the propylene group. At day's 3 and 5, the maximum pH was recorded by the propylene glycol group and minimum by the calcium hydroxide points and saline groups. At day 7, the pH of all the groups had dropped, with propylene glycol recording the maximum pH followed by saline and lastly calcium hydroxide points.

Conclusion: Within the limitations of this study, a viscous vehicle is better among other vehicles, calcium hydroxide paste of propylene glycol provided the highest 7 days release of hydroxyl ions.