The absence of proximal contact point on periodontal parameters of teeth moved into extraction sites.

The aim of study was to evaluate periodontal conditions of upper canines and second premolars with and without proximal contact of individuals undergoing orthodontic treatment associated to extractions of the upper first premolars. The study selected upper canines and premolars of individuals undergoing orthodontic treatment without extractions (30 hemiarches - control group), or with extraction of the upper first premolars and whose canines and second premolars had interproximal contact (16 hemiarches - group 1) or diastema (17 hemiarches - group 2). Clinical (plaque index, probing depth, gingival bleeding index, height of the gingival margin, clinical attachment loss and gingival clefts) and radiographic (crest height, bone height and bone-crest discrepancy) parameters of the distal surfaces of canines and mesial surfaces of premolars were evaluated.

Influence of the hyrax expander screw position on displacement and stress distribution in teeth: A study with finite elements.

Introduction: This study aimed to simulate the different positions of the hyrax appliance expander screw and evaluate tooth displacement and the stress distribution standard on the periodontal ligament using the finite element method.

Methods: Part of the maxilla with anchorage teeth, periodontal ligament, midpalatal suture, and the hyrax appliance was modeled, and finite element method models were created to simulate 6 different screw positions. There were 2 vertical positions at distances of 20 mm and 15 mm from the occlusal plane.

Influence of the hyrax expander screw position on stress distribution in the maxilla: A study with finite elements.

Introduction: Our objective was to evaluate the stress and deformation distribution patterns on the maxillary bone structure using the finite element method by simulation of different vertical and anteroposterior positions of the expansion screw on the hyrax expander appliance.

Methods: Part of the maxilla with anchorage teeth, midpalatal suture, and the hyrax appliance were modeled, and 6 distinct finite element method models were created to simulate different positions of the expansion screw. There were 2 vertical positions at distances of 20 and 15 mm from the occlusal plane.

Use of gray values in CBCT and MSCT images for determination of density: influence of variation of FOV size.

Purpose: To determine the effect of field of view (FOV) size on gray values in cone beam computed tomography (CBCT) and multislice computed tomography (MSCT) images.

Material And Methods: A phantom made up of 3 cylinders containing distilled water, plaster, and motor oil was constructed and inserted into an acrylic cylinder filled with distilled water. The phantom was scanned with a CBCT and MSCT device using 3 FOV sizes.

Influence of salivary secretory immunoglobulin A level on the pain experienced by orthodontic patients.

Background: Pain, a common experience reported by patients under orthodontic treatment, results from force application to the teeth and trauma caused by attrition of brackets and wires against the underlying oral mucosa. The main protection of the mucosa is secretory immunoglobulin A (sIgA), which may play a fundamental role in integrity maintenance and whose production may be reduced as a result of the stress of orthodontic treatment. The aim of this study was to assess sIgA levels in the saliva and their correlation with oral pain intensity in adults and children after the installation of fixed orthodontic appliances.