Biomedical subjects

H Chweidan

Publications and source records attributed to H Chweidan.

3 recordsLinked to original sources

PubMed1998

Posterior bite collapse--revisited.

Although there are different definitions of posterior bite collapse, only the classical definition of Amsterdam provides a definite diagnosis and treatment plan. This situation entails a subtle loss of the occlusal vertical dimension with resultant flaring of the maxillary incisors. Other causes for flaring, such as derangements of form and functions of lips and tongue, bruxism, habits, as well as the presence of advanced periodontal disease or malocclusions, should be ruled out before the diagnosis of posterior bite collapse can be made. The complexity of differential diagnosis is illustrated with three case reports.

Adult↗

PubMed1998

Bone regeneration for reintegration in peri-implant destruction.

Complications and deterioration around functional osseointegrated implants stem from two major factors: bacterial-initiated disease and overloading. Peri-implant breakdown can occur during the postsurgical phase and before the reconstructive phase as a result of surgical trauma and/or predisposed compromised recipient bone site. Technical errors also potentially contribute to bone loss, which results in the loss of osseointegration. Two case reports associated with peri-implant destruction are presented. The possible etiologic factors are discussed, and an attempt to regenerate lost peri-implant tissue is demonstrated via guided bone regeneration principles using barrier membranes.

Adult↗

PubMedDate not supplied

Cusp reinforcement by bonding of amalgam restorations.

The purpose of the present study was to assess the effectivenes of several adhesives in bonding amalgam in order to recover tooth stiffness. A non-destructive experimental methodology was adopted, using strain gauges bonded to the midbuccal surfaces of 40 teeth, with sequential evaluation of loaded intact, prepared and restored stages of the same tooth. Continuous strain measurement as a function of the applied load was acquired by A/D equipment and a data acquisition programme. The strain-force behaviour of the sound teeth under non-axial force up to 97.5 N served as the baseline. The five experimental groups (8 x 5) consisted of control (no adhesive) and four different adhesives. One-way analysis of variance with repeated measures was calculated for the deformation ratio, relative stiffness and recovery values. Reductions in tooth structure by cutting a mesio-occlusal-distal preparation, width one-third intercuspal distance, resulted in 39-52% loss of buccal cusp stiffness. Non-bonded amalgam produced negligible increase (5%) in the stiffness recovery values of the buccal cusps. The adhesives splinted the cusps together, thereby decreasing cuspal flexure and increasing relative stiffness values. Recovery values obtained ranged from 39% to 61%. Assuming that cusp fracture occurs as a result of brittle tooth structure fatigue, amalgam adhesives may contribute to the strengthening of weakened cusps.

Adhesives↗