Preparation and filling of small oval root canals: influence of file system and sealer.

Objective: To carry out a morphometric analysis of small oval root canals prepared with different instruments (part 1) and filled with different sealers (part 2).

Method And Materials: Ninety extracted mandibular incisors with small oval root canals were instrumented with Self-Adjusting File (n = 45), XP-endo Finisher (n = 15), GentleFile (n = 15), or Reciproc (n = 15). All groups of part 1 were filled with AH Plus (n = 15 each).

Evaluation of wear behavior of dental restorative materials against zirconia in vitro.

Objectives: To evaluate two-body wear (2BW) and three-body wear (3BW) of different CAD/CAM and direct restorative materials against zirconia using a dual-axis chewing simulator and an ACTA wear machine.

Methods: 3 CAD-CAM resin-based composite or polymer infiltrated ceramic network blocs, 1 lithium disilicate CAD-CAM ceramic (LS), 3 direct resin composites, amalgam and bovine enamel were tested. For 2BW, 8 flat specimens per material were produced, grinded, polished, stored wet (37 °C, 28d) and tested (49 N, 37 °C, 1,200,000 cycles) against zirconia.

Influence of Simulated Oral Conditions on Different Pretreatment Methods for the Repair of Glass-Ceramic Restorations.

Purpose: The present study investigated the influence of simulated intraoral conditions (increased temperature and humidity) on two different surface pretreatment methods to repair a lithium-disilicate glass-ceramic (LDS).

Materials And Methods: A total of 540 rectangular lithium-disilicate glass-ceramic bars were manufactured (3 x 7 x 9 mm; IPS e.max CAD, Ivoclar Vivadent).

Toughening by revitrification of LiSiO crystals in Obsidian® dental glass-ceramic.

As a predominantly lithium-metasilicate-containing glass-ceramic, Obsidian® (Glidewell Laboratories, USA) has a peculiar composition and microstructure among other dental lithium silicates, warranting an evaluation of the crystallization process to establish relationships between microstructural evolution and mechanical properties. Blocks of the pre-crystallized material were processed into slices measuring 12 × 12 × 1.5 mm and subjected to the mandatory crystallization firing by interruption the heating ramp at temperatures between 700 °C and 820 °C (dwell time between 0 min and 10 min).

Inner marginal strength of CAD/CAM materials is not affected by machining protocol.

Purpose: Here we aimed to compare two machining strategies regarding the marginal strength of CAD/CAM materials using a hoop-strength test in model sphero-cylindrical dental crowns, coupled with finite element analysis.

Materials And Methods: Five CAD/CAM materials indicated for single posterior crowns were selected, including a lithium disilicate (IPS e.max CAD), a lithium (di)silicate (Suprinity PC), a polymer-infiltrated ceramic scaffold (Enamic), and two indirect resin composites (Grandio Blocs and Lava™ Ultimate).