Do instrument kinematics and the apical preparation limit influence canal disinfection and bacterial extrusion?

This in vitro research assessed the influence of the instrument kinematics (rotary and reciprocating) and the apical preparation limit on the root canal disinfection and apical bacterial extrusion. After 21 days of Enterococcus faecalis biofilm formation in 72 mesial root canals of mandibular molars, the root canals were distributed into 2 groups (n = 36) according to the systems used for preparation: ProDesign S and Reciproc. The groups were redistributed according to the limit of apical preparation (n = 11): (a) 1 mm up to the apical foramen (TL-1); (b) at the apical foramen (TL = 0); (c) 1 mm beyond the apical foramen (TL + 1).

Effect of final irrigation protocols on the structural integrity and mechanical properties of the root dentine.

This study compared the effects of different final irrigation protocols on the mechanical properties and structural integrity of root dentine. One-hundred eight teeth were instrumented and irrigated with sodium hypochlorite (NaOCl) using conventional irrigation (CI). Teeth were distributed into four groups based on final irrigation protocols: Control Group (CG): 17%EDTA/CI + H2O; G1: 2.

Do the apical limit and diameter of the instrumentation influence the extrusion of sodium hypochlorite solution? A micro-CT study.

This study evaluated the influence of the apical limit and the diameter of the instrumentation on the extrusion of the irrigating solution. Sixty human lower premolars were distributed into 5 groups according to the apical limit and diameter of the root canal instrumentation (n = 12): (G-1) R40 instrument 1 mm above the tooth length (TL) (Control); (G-1) R50 instrument 1 mm above the TL; (GF) R25 instrument at the TL; (GF) R40 instrument at the root canal length and (GF) R50 instrument at the TL. A space of 33.

Ultrasonic activation of adhesive systems increases bond strength and intratubular penetration of resin cement in root dentin subjected to radiation therapy.

Objective: This study aimed to evaluate the effect of ultrasonic activation of etch-and-rinse and self-etch adhesive systems on the bond strength of resin cement to irradiated root dentin.

Materials And Methods: Eighty human maxillary anterior teeth were distributed into 8 groups (n = 10), according to the type of adhesive system used (etch-and-rinse and self-etch), the ultrasonic activation of the adhesive systems, and the dentin condition (irradiated or non-irradiated - 70 Gy). Endodontic treatment was performed followed by fiberglass post-space preparation.

Assessment of multispecies biofilm growth on root canal dentin under different radiation therapy regimens.

Objectives: To assess the growth of a multispecies biofilm on root canal dentin under different radiotherapy regimens.

Materials And Methods: Sixty-three human root dentin cylinders were distributed into six groups. In three groups, no biofilm was formed (n = 3): NoRT) non-irradiated dentin; RT55) 55 Gy; and RT70) 70 Gy.