Palatal bone support for orthodontic implant anchorage--a clinical and radiological study.
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When maximal anchorage is required during orthodontic treatment, additional aids are often needed to support the anchoring teeth. While intra-oral aids may be limited in their anchorage potential, extra-oral anchoring aids are often rejected by the patients. Endosseous implants may therefore be a valuable alternative for stable intra-oral anchorage. However, the possibility of using conventional implants is insufficient, e.g. for treating purely orthodontic patients with full dentition or where extraction sites are to be closed. Therefore, the mid-sagittal area of the palate is an alternative insertion site for the placement of implants for orthodontic anchorage. The limited bone height in this area inspired this comparison between bone thickness in the implantation site as verified by probing during the implantation of Straumann Ortho-system implants, and thickness as measured on the lateral cephalogram. The results suggest that vertical bone support is at least 2 mm higher than apparent on the cephalogram. In none of 12 patients was a perforation to the nasal cavity found. However, in five subjects the implant projected into the nasal cavity on the post-operative cephalogram. These results were supported by the study of the projections of palate and wires in wire-marked skulls where the wires were placed bilaterally on the nasal floor and on the nasal crest. It is therefore concluded that the mid-sagittal area of the palate lends sufficient bony support for the implantation of small implants (4-6 mm endosseous length, diameter 3.3 mm). (+info)
Motivation for and satisfaction with orthodontic-surgical treatment: a retrospective study of 28 patients.
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Motivation for starting treatment and satisfaction with treatment results were evaluated on the basis of replies to a 14-item questionnaire and clinical examination of 28 orthognathic patients from 6 months to 2 years after treatment. The most common reasons for seeking professional help were problems in biting and chewing (68 per cent). Another major reason was dissatisfaction with facial appearance (36 per cent). Many patients also complained of temporomandibular joint symptoms (32 per cent) and headache (32 per cent). Women (8/19) were more often dissatisfied with their facial appearance than men (2/9), but the difference was not statistically significant. In agreement with earlier studies, the results of orthognathic treatment fulfilled the expectations of almost every patient. Nearly 100 per cent of the patients (27/28) were satisfied with treatment results, although 40 per cent experienced some degree of numbness in the lips and/or jaw 1 year post-operatively. The most satisfied patients were those who stated temporomandibular disorders as the main reason for seeking treatment and whose PAR-index had improved greatly. The majority of the patients experienced the orthodontic treatment as painful and as the most unpleasant part of the whole treatment, but all the patients were satisfied with the pre-treatment information they were given on orthodontics. Orthodontic-surgical therapy should be of a high professional standard technically, but the psychological aspects are equally important in the treatment protocol. The professionals should make efforts to understand the patient's motivations for and expectations of treatment. Patients should be well prepared for surgery and supported for a long time after to help them to adjust to post-surgical changes. (+info)
The crystal growth technique--a laboratory evaluation of bond strengths.
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An ex vivo study was carried out to determine differences in the bond strengths achieved with brackets placed using a crystal growth technique compared with a conventional acid-etch technique. A solution of 37 per cent phosphoric acid was used for acid-etching and a commercially available polyacrylic acid gel, Crystal-lok for crystal growth. A heavily-filled composite resin was used for all samples to bond brackets to healthy premolar teeth extracted for orthodontic purposes. Polycrystalline ceramic and stainless steel brackets were used and tested to both tensile and shear failure using an Instron Universal Testing machine. The tensile and shear bond strengths were recorded in kgF. In view of difficulties experienced with previous authors using different units to describe their findings, the data were subsequently converted to a range of units in order to facilitate direct comparison. The crystal growth technique produced significantly lower bond strengths than the acid-etch technique for ceramic and stainless steel brackets, both in tensile and shear mode. The tensile bond strength for stainless steel brackets with crystal growth was 2.2 kg compared with 6.01 kg for acid-etch, whilst with ceramic brackets the tensile bond strengths were 3.9 kg for crystal growth and 5.55 kg for acid-etch. The mean shear bond strength for stainless steel brackets with crystal growth was 12.61 kg compared with 21.55 kg for acid-etch, whilst with ceramic brackets the shear bond strengths were 7.93 kg with crystal growth compared with 16.55 kg for acid-tech. These bond strengths were below those previously suggested as clinically acceptable. (+info)
Multi-bracket appliance in management of mandibular reconstruction with vascularized bone graft.
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BACKGROUND: The most commonly used tool for maxillo-mandibular fixation to the patient who underwent reconstruction using a vascularized bone graft after mandibular resection is a dental arch-bar. However, the occlusal relationship achieved by this method is not ideal. Different from the dental arch-bar, the multi-bracket appliance which is frequently used in orthodontic treatment can control the position of each individual tooth three dimensionally. Thus, this appliance was applied for maxillo-mandibular fixation to patients who underwent mandibular reconstruction using a vascularized bone graft. METHODS: A multi-bracket appliance was applied to three patients. Prior to the surgery, standard edgewise brackets were bonded to the teeth in the maxilla and in the remaining mandible. After mandibular resection, wires for maxillo-mandibular fixation were applied. The harvested bone was then carefully fixed with miniplates to maintain the occlusion. The multi-bracket appliance was worn for 3 months when the wound contraction became mild. RESULTS: All three cases demonstrated stable and good occlusion. They also demonstrated satisfactory post-surgical facial appearance. CONCLUSIONS: Compared to conventional dental arch-bars, a multi-bracket appliance offers improved management of mandibular reconstruction. Firstly, its properties are helpful in maintaining occlusion of the remaining dentition accurately in bone grafting procedure as well as protecting against postsurgical wound contraction. Secondly, the multi-bracket appliance keeps the oral cavity clean without periodontal injury. As a result, stable occlusion of the residual teeth and good facial appearance were obtained. (+info)
A comparison of sagittal and vertical effects between bonded rapid and slow maxillary expansion procedures.
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The purpose of this study was to determine the vertical and sagittal effects of bonded rapid maxillary expansion (RME), and bonded slow maxillary expansion (SME) procedures, and to compare these effects between the groups. Subjects with maxillary bilateral crossbites were selected and two treatment groups with 12 patients in each were constructed. The Hyrax screw in the RME treatment group and the spring of the Minne-Expander in the SME treatment group were embedded in the posterior bite planes, which had a thickness of 1 mm. At the end of active treatment these appliances were worn for retention for an additional 3 months. Lateral cephalometric radiographs were taken at the beginning and end of treatment, and at the end of the retention period. The maxilla showed anterior displacement in both groups. The mandible significantly rotated downward and backward only in the RME group. The inter-incisal angle and overjet increased in both groups. No significant differences were observed for the net changes between the two groups. (+info)
Rare earth magnets in orthodontics: an overview.
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Magnets have been used in dentistry for many years. They can be made to push or pull teeth. The force they deliver can be directed, and they can exert their force through mucosa and bone, as well as within the mouth. In orthodontics they are used for intrusion of teeth, tooth movement along archwires, expansion, retention, in functional appliances, and in the treatment of impacted teeth. New 'high energy' magnets are capable of producing very high forces relative to their size. Although magnets are potentially very useful there are a number of problems that severely affect their performance; the force produced between any two magnets falls dramatically with distance, significant irreversible loss in force is seen if the magnets are heated and a dramatic reduction in force is seen if the magnets are not ideally aligned to one another. In addition, magnets corrode badly in the mouth and a robust coating is required to protect them. This paper outlines the background to high energy magnets used in orthodontics, discusses the relevant physical and biological properties of them, and reviews their applications. (+info)
Patients' anticipation of pain and pain-related side effects, and their perception of pain as a result of orthodontic treatment with fixed appliances.
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The aim of this study was to investigate the relationship between (i) the pain and its side effects, anticipated by patients before orthodontic therapy, and (ii) the reported pain and its effects after the placement of initial archwires. Before treatment, 50 adolescent patients (median age 13.6 years, range 8.9-39.3 years, 28 female, 22 male) completed a questionnaire concerning their facial and dental appearance, and their expectations regarding pain, its influence on their daily lives, and changes in their facial and dental appearance as a result of orthodontic treatment. In the week following insertion of the initial archwires the patients completed a series of eight questionnaires, where they reported the level of pain experienced and its influence on their daily lives. In the week after archwire insertion, the maximum pain levels reported did not differ statistically from the anticipated pain levels. Patients significantly under-estimated the changes they would have to make in their diet as a response to pain after archwire insertion. Patients who anticipated a greater effect of pain on their leisure activities and those who had a history of frequent headaches reported higher levels of pain and more disruption of their daily lives as a result of pain. This pattern of response is consistent with a medical model where anxious patients and those with a history of chronic pain reported more pain after surgery. (+info)
Sensory and motor changes of the human jaw muscles during induced orthodontic pain.
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The aim of this study was to evaluate the short-term effects of orthodontic pain on the pressure pain threshold (PPT) of the masseter and anterior temporalis muscles, and on their electromyographic (EMG) activity during clenching and chewing. Orthodontic pain was induced in 14 healthy subjects (mean age 26.6, SEM 1.1) by placing orthodontic separators. The subjects were randomly assigned to an experimental and to a control session in a double-blind crossover study. PPT was significantly reduced (Student's t-test; P < 0.001) after experimental sessions for both the masseter and the anterior temporalis muscles, whereas no significant differences were found during control sessions (P > 0.05). EMG activity during clenching and chewing was significantly reduced (0.001 < or = P < 0.05) after experimental sessions for both masseter and anterior temporalis muscles, whereas no significant differences were found during control sessions (P > 0.05). The decrease of PPT found in this study can be related to the occurrence of muscle pain and headache reported by patients during orthodontic or other dental treatment. The decrease of EMG activity of the jaw muscles associated with orthodontic pain is consistent with the pain adaptation model and should be considered as a potential factor for loss of occlusal anchorage during orthodontic treatment. (+info)