The effect of calcium hydroxide root filling on dentin fracture strength

– This in vitro study measured the effect of calcium hydroxide root filling on the microtensile fracture strength (MTFS) of teeth. A total of 40 extracted human disease‐free permanent maxillary incisors were hand and rotary instrumented and vertically compacted with United States Pharmacopeia (USP) calcium hydroxide. The teeth were stored in a moist environment for 7, 28, and 84 days. As a control group, 10 teeth were vertically compacted with gutta percha and sealer. The MTFS of the teeth was measured (Mpa) using an Instron machine. Data were assessed statistically using an unpaired t‐test (P value). The intracanal placement of calcium hydroxide weakened the MTFS of teeth by 13.9 Mpa per 77 days: an average of 0.157 MPa day−1. Between 7 and 84 days, the MTFS of the dentin was reduced by 43.9%. This difference was statistically significant (P