Dental Materials Commons^™

Plastic Deformation Of A Polycarbonate Bracket : Utilizing A New Testing Apparatus, Terri L. Alfred

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to investigate the plastic (permanent) deformation of a polycarbonate bracket (Miura, RMO) under the following different conditions: (1) untreated, (2) immersed in 37°C-water for 120 days, and (3) immersed in 60°C-water for 24 hours. Ten brackets for each condition were tested, with a total of 30 brackets tested. Each bracket was bonded to a metal mesh pad which was tack welded to a solid stainless steel ring. The assembly was placed under a loading frame. This loading frame removes variables such as bond adhesive strengths, distortion of a wire used to deform the bracket …

A Comparison Of Retentive Strengths Of Two Types Of Inner Surface Treatments Of Orthodontic Bands, Jean M. Rathbun

Loma Linda University Electronic Theses, Dissertations & Projects

Band failure during orthodontic treatment results in a potential for decalcification and/or caries and may cause a prolonged treatment time. An increase in the bond strength at the cement/band interface would likely decrease clinical band failure. Sand-blasting and photo-etching have been suggested to improve this bond.

This study investigated the retentive strengths of untreated orthodontic bands, sand-blasted bands and photo-etched bands when cemented with glass polyalkenoate cement on extracted human molars. The sand-blasted bands and photo-etched bands were both found to have significantly stronger bond strengths (p

The Effects Of Rapid Palatal Expansion Therapy On The Periodontal Tissues Of The Central Incisors, Richard Gutierrez

Loma Linda University Electronic Theses, Dissertations & Projects

The periodontal structures around the maxillary central incisors in thirty-nine post-orthodontically treated patients, twenty-five of these patients had experienced Rapid Palatal Expansion (RPE), were examined to determine the periodontal consequences associated with two ways of managing the resultant diastema. In fourteen patients the diastema closure was assisted by elastomeric chain and in eleven patients the diastema closure was not assisted. Fourteen non-RPE orthodontically treated patients served as controls. Height of attached gingiva, gingival sulcus depth, attachment level, and alveolar bone level were recorded. One examiner, using calibrated techniques, performed all the measurements. The RPE groups and the control group all …