Shahreen Zahid, Samie Qadir, Asfia Saeed, Muhammad Kaleem.
The influence of moisture on the setting time of the latest commercially available calcium hydroxide cements: a clear guideline for the Dentist.
Pak Oral Dental J Jan ;36(4):691-6.

Calcium hydroxide is a material of choice for pulp capping procedure and is widely used for lining, apexification and root canal dressing. The objective of this study was to evaluate the influence of humidity and temperature on the setting time of four different commercially available calcium hydroxide cements. For each material 10 samples were prepared according to manufacturer’s instructions. Then each material was further divided in to two groups using two different ISO standards. In group A, specimens were allowed to set at 37°C and ≤ 90% relative humidity, in a water bath to mimic humidity and temperature conditions of oral cavity without the use of rubber dams. In group B, specimens were tested at 25°C and 50%-57% relative humidity to simulate the effect of rubber dams. All the samples were tested for setting time by Gilmore needle. Setting times were noted when the indenters failed to make a circular indentation on the surface of cement. Data was analyzed with one-way analysis of variance (ANOVA) and post hock Tukey’s test using SPSS 21. The results showed a significant difference (p <0.05) between group A and B, showing that the setting of the calcium hydroxide cement is delayed by increase in moisture and temperature. Thus it highlights the importance of using rubber dam in clinical practice. Moreover, the results of the study provides a guideline for the clinician to choose the type of calcium hydroxide needed in a particular situation based on determined setting times.

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