Palatal bone support for orthodontic implant anchorage--a clinical and radiological study.
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.
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)
Incremental growth charts for condylar growth between 6 and 16 years of age.
This study provides sex specific reference data for the incremental growth of the mandibular condyle. The results pertain to a mixed-longitudinal sample of 113 males and 108 females followed annually between 6 and 16 years of age (total of 1647 observations). Growth of condylion was evaluated using naturally stable mandibular reference structures. The mean growth curves were estimated by multilevel models using iterative least squares procedures; between subject variation was estimated based on the sample's percentile distributions. Mean yearly velocities of condylar growth for males ranged between 2.1 and 3.1 mm/year. Growth rates decreased during childhood, increased during adolescence, and attained a maximum of 3.1 mm/year at approximately 14.3 years of age. Females showed a more constant rate of condylar growth during childhood (2.0-2.7 mm/year), a smaller adolescent peak (2.3 mm/year) at approximately 12.2 years and rapid deceleration after the peak. These reference data offer orthodontists an objective means of evaluating growth potential and treatment outcome in individual patients. Charts are provided for evaluating condylar growth of individual patients. (+info)
An appraisal of the Peer Assessment Rating (PAR) Index and a suggested new weighting system.
The PAR Index was developed to measure treatment outcome in orthodontics. Validity was improved by weighting the scores of some components to reflect their relative importance. However, the index still has limitations, principally due to the high weight assigned to overjet. Difficulties also arise from the application of one weighting system to all malocclusions, since occlusal features vary in importance in different classes of malocclusion. The present study examined PAR Index validity using orthodontic consultant assessments as the 'Gold standard' and clinical ranking of occlusal features and statistical modelling to derive a new weighting system, separate for each malocclusion class. Discriminant and regression analyses were used to derive new criteria for measuring treatment outcome. As a result a new and more sensitive method of assessment is suggested which utilizes a combination of point and percentage reductions in PAR scores. This was found to have better correlations with the 'Gold standard' than the PAR nomogram. (+info)
A modification to enable controlled progressive advancement of the Twin Block appliance.
A modification of the Twin block appliance has been developed to facilitate controlled gradual advancement of the mandibular position during the treatment of Class II division I malocclusions. This features the incorporation of stainless steel screws with conical heads into the blocks of the upper appliance to provide the inclined plane effect. Advancement is by the addition of polyacetal spacers between the screw heads and the upper blocks. The system is designed to improve the clinical flexibility of the appliance and to enhance patient acceptance in cases where mandibular protrusion is limited initially. Another possible application is gradual reactivation for Class III correction. Other advantages are reduced laboratory and clinical time during reactivation of the appliance, and perhaps a more physiological response to the growth modification process. The design and construction of the advancement system is illustrated, and its clinical use discussed. (+info)
Assessment of clinical case presentations for the Membership in Orthodontics, Royal College of Surgeons of England 1995, 1996.
The cases presented and treated at successive examinations by the candidates for the Membership Examination in Orthodontics in 1995 and 1996 at The Royal College of Surgeons of England, were of a very high standard and demonstrated a wide range of treatment modalities. All cases had fixed appliances, predominantly with pre-adjusted Edgewise appliances. IOTN confirmed that most cases were in great need of treatment, with PAR scores showing them to be treated to a high standard. (+info)
Initial tooth displacement in vivo as a predictor of long-term displacement.
In the past, the dry skull has been used as a hypothetical model to test initial orthodontic and orthopaedic force systems. However, the question as to whether this hypothetical model can be used as a predictor of long-term displacements in vivo remains unanswered. In this study, an attempt was made to compare initial tooth displacement with the long-term effect after application of the force system for a longer period of time, in six adult dogs. Tooth displacement was obtained by applying a force by means of a coil spring (push) system. Following application of a force of 50 g in the first series (n = 3) and 80 g in the second series (n = 3), initial displacements were registered by means of speckle interferometry. The long-term displacement was registered by means of standardized cephalometry in the same dog by leaving the force system in place for 5 weeks. The mean values of the displacement vectors of the second premolars in the six dogs were compared. A paired t-test revealed no significant differences between the initial and long-term displacements in any of the dogs. The results show that both groups of measurements belong statistically to the same sample and that initial tooth displacement measured by means of speckle interferometry is a valuable predictor for forecasting long-term displacement in vivo after 5 weeks. (+info)
Residual need in orthodontically untreated 16-20-year-olds from areas with different treatment rates.
Knowledge concerning residual orthodontic need among individuals who have passed the age at which orthodontic treatment is normally provided, is important in the discussion of guidelines for the provision of care. The purpose of the present study was to examine and compare orthodontic need (objective and subjective) in cohorts of orthodontically untreated individuals from areas with various treatment rates. A total of 250 individuals, aged 16-20 years, comprised four samples representing cohorts from areas in Norway with low, medium, and high treatment rates. The occlusion was assessed according to a treatment need index (NOTI) from clinical and radiographic records, and dental cast measurements. Attitudes were assessed from questionnaires addressing satisfaction with dental arrangement, desire for treatment, and value placed upon well-aligned teeth. A significant decrease in occurrence of normative need (P < 0.001) and reported dissatisfaction (P < 0.05) was observed in samples representing increasing treatment rates. Dissatisfaction was completely eliminated among individuals from the high treatment rate area. Although a significant association between severity of malocclusion and desire for treatment existed within samples, this was not reflected in a corresponding trend for a decrease in desire across the samples. Well-aligned teeth seemed to be taken for granted among individuals from the area with a high treatment rate. From the present observations, a 'correct' level of treatment provision could not be identified. (+info)