Wear behavior of CAD-CAM zirconia, ceramic, and 3D printed nano-hybrid resin crowns for the restoration of primary and permanent molars: An in vitro study.

Statement Of Problem: Early childhood caries is one the world's most common problems in infants and treatment of posterior teeth with esthetic crowns in a low rate of wear on opposite dentition is a challenge for pediatric dentists.

Purpose: The purpose of this in vitro study was to evaluate the wear behavior of the tooth colored crown materials and the opposing teeth in using different esthetic crown materials in the mixed dentition period.

Material And Methods: The following tooth type and crown materials were considered in the experiment.

Biomechanical and clinical assessment of dissociation in bipolar hip hemiarthroplasty.

Background: Dissociation is a special type of dislocation that is rarely seen in bipolar hemiarthroplasty.

Objective: To investigate the clinical and biomechanical causes of dissociative dislocation of acetabular cup components in the hips of patients after bipolar hemiarthroplasty (BHA).

Methods: BHA heads were divided into three groups according to their design.