Edition V03N03 | Year 2013 | Editorial Original Article | Pages 32 to 35
Introduction: The antimicrobial effect of calcium hydroxide has been assigned to its capacity to produce an alkaline shift in pH. This property is affected when calcium hydroxide is combined with other substances, such as 2% chlorhexidine gel and zinc oxide, which makes the action of the paste last longer.
Objective: This study assessed whether calcium hydroxide paste associated with chlorhexidine gel and zinc oxide promote pH shifts at short time intervals.
Methods: Calcium hydroxide pastes prepared with three vehicles: saline solution (paste A); propylene glycol (paste B); and 2% zinc oxide chlorhexidine gel (paste C) were placed into vials containing 15 ml of deionized water. A pH meter was used to detect pH shifts of combinations in different vehicles at seven time intervals: 15 and 30 minutes; 1, 24 and 48 hours; as well as 7 and 14 days.
Results: All three pastes presented a sharp increase of pH values at the first time interval and remained relatively stable at a value of about 12 from 24 hours to 7 days. After this period, the pH of pastes A and B decreased to 9.50, whereas that of paste C remained at 12.
Conclusions: Pastes A and B produced a faster alkaline shift of the solution, whereas paste C kept an elevated pH for a longer time, however, differences were not statistically significant.