Upper molar intrusion in rehabilitation patients with the aid of microscrews
Department of Orthodontics, Latin American Institute of Dentistry Research and Education, Curitiba, PR, Brazil. Australian orthodontic journal
(Impact Factor: 0.43).
Overeruption of an upper molar following loss of the opposing tooth is a common clinical finding. Rehabilitation can be difficult when the interocclusal space is reduced.
To intrude an overerupted upper first molar and replace the missing lower first molar.
Buccal and palatal microscrews and a transpalatal bar were placed. The palatal miniscrew loosened shortly after implantation and was not replaced. A short length of elastomeric chain from the buccal miniscrew applied 30 g of force to the overerupted molar. The elastomeric chain was replaced every four weeks.
Sufficient intrusion of the upper molar was obtained in 4 months.
A single buccal microscrew and transpalatal arch can be used to intrude an overerupted upper molar.
Available from: Alejandro Romeo
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ABSTRACT: The overeruption of upper molars due to the premature loss of antagonist teeth can be treated with the help of miniscrews. The aim of this study was to evaluate the movement of a typodont molar according to the biomechanical approach used with miniscrews.
The study was conducted with four plaster models filled with typodont wax. In each model we used one absolute anchorage on the palatal side and another on the buccal side in different positions, thus generating four different biomechanical systems. A force of 150 g was applied to each side of the resin tooth. Periapical radiographs were taken preintrusion and immediately after completion of the intrusion. Photographs were taken in both the sagittal and occlusal planes every 3 min. The radiographic films and photographs were measured and compared.
A vertical movement of the molar was observed in all the models, with system 4 showing the greatest movement. Rotation in the occlusal plane only occurred in system 2, while in system 1 there was a change in the axial axis of 37 degrees.
The anchorage site and the combination of forces applied may determine the resulting tooth movement.
Available from: Ali Borzabadi-Farahani
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ABSTRACT: The present paper provides an overview of orthodontic considerations in restorative management of hypodontia patients with endosseous implants. The treatment of hypodontia patients with implant supported restorations can be challenging. This is a multi-phase treatment that begins in late mixed dentition and finishes at late adolescence. Careful treatment planning is required to protect against excessive forces or overloading of endosseous implants. The lack of periodontal ligament and absent or very limited proprioceptive nerve endings makes implant susceptible to overloading and failure. When teeth are extracted or congenitally missing, adjacent or opposing teeth may tip, drift or over-erupt and leaving edentulous spaces that are not favorable for implant placement. Hypodontia patients may present with skeletal features such as short and retrognathic maxilla, prognathic mandible, and shorter lower anterior facial height. Dental arches in hypodontia patients show a variety of problems such as bimaxillary retroclination of incisors, spacing, centerline discrepancies, microdontia, hypoplastic enamel, ankylosis of retained deciduous teeth, over-eruptions, and deficient alveolar ridges. A minimum required bone volume is needed for successful placement of implants and should be considered when formulating the treatment plan. Some orthodontic strategies for preserving and augmenting the implant site are briefly discussed. These include the orthodontic extrusion, delayed orthodontic space opening, and orthodontic implant site switching technique. It is important to retain the teeth in their final planned position with a rigid bonded retainer. Overlooking this phase of orthodontic treatment can compromise the implant site and necessitate further orthodontic treatment.
Available from: Anand K Patil
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