Cement Insertion Technique Effect on Layer Cement of Fiber Posts

Objective: To evaluate the effect of different insertion cement techniques (ICTs) on the cement layer quality (CLQ) of fiber post luted to bovine root dentin. The hypothesis was that ICTs affect the CLQ. Methods: The canals of forty single-root bovine roots (16mm in length) were prepared at 12mm using the preparation drill (FRC Postec Plus, Ivoclar). Each specimen (sps) was included in a resin acrylic from the 4 mm apical portion of the root, using an adapted surveyor, and the sps were divided into four groups, according to the methods of cement insertion (N=10):Gr1-Lentulo drill;Gr2-Centrix syringe;Gr3-Explorer #5;Gr4-with the assistance of fiber post. The sps were treated with the adhesive system (All Bond 2) and the fiber posts (Aestheti Plus) were luted (RelyX) and the sps were stored (water: 24 h, 37° C). Each specimen was cut in 3 thirds (apical, middle and cervical) with thickness of 0.5 mm each. Each sample was analyzed under a digital Optical Microscope (100X) (Mitutoyo) to evaluate the CLQ, through the attribution of scores: 1- Absence of bubbles; 2- Up to 10 bubbles (Φ£0.1mm);3- 10 to 20 bubbles (Φ£0.1mm); 4- More than 20 bubbles (Φ£0.1mm);5-Up to 10 bubbles (Φ£0.1mm) + bubble(s) (0.11£ Φ £0.5mm);6- 11 to 20 bubbles (Φ£0.1mm) + bubble(s)(0.11£ Φ £0.5mm);7-More than 20 bubbles (Φ£0.1mm) + bubble(s)(0.11£ Φ £0.5mm);8-Bubble(s)(0.51£ Φ £0.6mm); 9-Bubble(s) (0.61£ Φ £0.7mm); 10-Bubble(s) (Φ>0.7mm).The data were statistically analyzed with Kruskal-Wallis One-Way (p<0.05) and Dunn (10%) tests. Results: Kruskal-Wallis showed that the CLQ was affected by the ICTs (p=0.0044):Gr1a (median=3.8), Gr2a (median=3.2), Gr3a,b (median=5.2) and Gr4b (median=5.2) (Dunn test). The hypothesis was accepted. Conclusions: The lentulo drill and centrix syringe are the methods more appropriate to insert resin cement into the root canal.