Effect of electric tooth brushing on retention of long-term provisional composite crowns

Abstract Aim This in-vitro study was conducted to evaluate the influence of electric tooth brushing on the retention of long-term provisional crowns cemented with three cement types. Setting and design In vitro-comparative study. Materials and methods Ninety extracted upper premolars were prepared and provisional crowns were fabricated and cemented with three different cements; group 1: resin-modified zinc oxide-eugenol (i-ZOEn), group 2: zinc oxide noneugenol (Temp Bond NE), and group 3: calcium hydroxide (Dycal). All the specimens were subjected to a chewing simulator with thermocycling (5–55°C) according to the time of exposure to electric tooth brushing (6 and 12 months). A universal testing machine was used for retention test, all specimens were subjected to (pull-out test). Statistical analysis used Two-way analysis of variance ( P < 0.001) was considered significant difference in all tests. Results Maximum force (N) at baseline, 6, and 12 months groups for tensile dislodgement of zinc oxide-eugenol cemented crowns was 69.81 ± 4.32, 44.74 ± 4.39, and 41.88 ± 1.03 N, for zinc oxide noneugenol cemented crowns was 57.83 ± 7.44, 34.87 ± 1.07, and 20.22 ± 1.82 N and for calcium hydroxide cemented crowns was 74.61 ± 0.96, 45.05 ± 2.15, and 31.32 ± 8.29 N, respectively, with P value less than 0.001. Conclusion Electric toothbrush effect on long-term provisional crowns was significant for the crowns cemented with three different types. Calcium hydroxide was the most retentive cement at baseline group and 6 month periods with no clinical significance with resin-modified zinc oxide-eugenol. Resin-modified ZOE was the most retentive cement at 12-month periods with a clinically significant difference with calcium hydroxide. Zinc oxide noneugenol was the least retentive cement throughout all the times.