(1/85) 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)
(2/85) Skeletal and dental changes following the use of the Frankel functional regulator.
The purpose of this study was to assess the relative contributions of skeletal and dental components in correction of Class II division 1 malocclusions when treated with Frankel's functional regulator (FR). This was a retrospective study involving analyses of pre- and post-treatment cephalograms of 63 Class II division 1 patients treated with the FR to demonstrate the relative maxillary, mandibular, incisor, and molar movements during treatment compared with normal growth within a control group of untreated 39 Class II division 1 cases drawn from the same demographic population. All cephalograms were digitized and subjected to a Pitchfork analysis, which measured individual anteroposterior skeletal and dental changes during the period of study. It was shown that the FR was effective in treating Class II division 1 cases with the studied group being corrected to a clinically acceptable overjet and overbite of 2-3 mm. The majority of the correction came from dental movements, the most significant being the retroclination of the upper incisor teeth (mean 4.1 mm, 95 per cent CI +/- 0.44) and proclination of the lowers (mean 2.2 mm 95 per cent CI +/- 0.57). As regards skeletal correction, the most significant contribution was the restraint of normal maxillary forward growth (mean -0.2 mm, 95 per cent CI +/- 0.62) with forward mandibular growth not being a significant factor. (+info)
(3/85) An investigation into the changes in airway dimension and the efficacy of mandibular advancement appliances in subjects with obstructive sleep apnoea.
This prospective clinical study evaluates a group of 37 male Caucasians with obstructive sleep apnoea for changes in airway dimension and the efficacy associated with the use of mandibular advancement splints. Lateral skull radiographs were obtained with the subjects--upright in occlusion, supine in occlusion, and supine in protrusion. Each radiograph was traced and digitized, and changes in mandibular position, airway dimensions, and hyoid were examined. Subjects were invited to complete pre- and post-treatment questionnaires, and interviewed following fitting of a removable Herbst mandibular advancement splint. Significant changes were recorded in the airway dimensions in response to both a change in position, from upright to supine, and in response to mandibular advancement. A compliance rate of 76 per cent was achieved with no reported serious complications associated with the use of mandibular advancement devices. (+info)
(4/85) Predicting the outcome of twin block functional appliance treatment: a prospective study.
A prospective study was undertaken to investigate the relationship between various measured pre-treatment parameters and the reduction in overjet achieved when using a twin block functional appliance. Forty-three subjects were fitted with a twin block functional appliance, and a number of pre-treatment clinical and radiographic morphological features were recorded. The functional appliance wear was monitored for 6 months and any individual who did not co-operate with wear was excluded from the subsequent analysis. Multiple regression analysis with stepwise inclusion was used to relate the percentage reduction in overjet achieved by functional appliance wear to any of the pre-treatment parameters. The data from 22 individuals was included in the final analysis. The overbite and SNB angle were the most strongly related variables to percentage reduction in overjet. These were then used to construct a predictive equation for the expected percentage reduction in overjet: Percentage reduction in overjet in 6 months = 132 + 4.9x1 - 1.4x2, where x1 = overbite and x2 = SNB. The pre-treatment overbite was, in isolation, the most influential feature in predicting the percentage of overjet reduction. (+info)
(5/85) A comparison of three superimposition methods.
The purpose of this investigation was to compare the reliability of three superimposition methods: Bjork's structural, Ricketts' four-position, and Pancherz's method. The material consisted of 14 pairs of cephalograms obtained before and after Herbst treatment. Each pair of cephalograms were traced and superimposed by means of the three different methods three times each. A reference grid was used to quantitatively evaluate the sagittal dental and skeletal changes. The results revealed that: (1) there was no statistically significant difference between the repeated measurements in the three methods, i.e. all three methods were reliable. (2) There was no significant difference among the three superimposition methods to evaluate the sagittal skeletal and dental changes. (3) Comparing the coefficient of reliability, none of the three methods was suitable for individual assessment, and Pancherz's method only was acceptable for assessment of patients in groups. (+info)
(6/85) The effect of a maxillary lip bumper on tooth positions.
The effect of the use of a lip bumper with anterior vestibular shields on the maxilla was studied in twenty-two 9-14-year-old children with a space deficiency in the maxillary dental arch. The lip bumper was used for 1 year. The effect of the treatment was evaluated from dental casts and profile cephalograms made before and after treatment. Both the width of the maxillary dental arch at the premolars and the length of the arch increased significantly by about 2 mm. The effect of the treatment on the antero-posterior position of the first molars was small. In one subject the molar was distalized 2.8 mm. The average effect was, however, a reduction in the anterior movement of the molar within the face by about 0.5 mm, i.e. the maxilla moved anteriorly 1 mm, but the molar only 0.4 mm. No skeletal effects were found when the group of subjects treated with a lip bumper was compared with a reference sample of untreated individuals. The main effects of a maxillary lip bumper thus seem to be a widening of the dental arch across the premolars, a moderate increase in arch length due to eruption and slight proclination of the incisors, and moderate distal tipping of the first molars. (+info)
(7/85) Functional and social discomfort during orthodontic treatment--effects on compliance and prediction of patients' adaptation by personality variables.
During the course of treatment orthodontic patients frequently endure a number of functional complaints and are anxious about their appearance. The aims of this longitudinal study were to follow the progress of patients' adaptation to discomfort, to elucidate the putative relationship between the type of appliance worn and functional and social discomfort experienced, to study potential predictability by their attitude to treatment and to evaluate the effects of discomfort as predictors of patients' compliance. Eighty-four patients undergoing either removable, functional, or fixed appliance treatment monitored their complaints during the first 7 days of treatment and rated them retrospectively 14 days, and 3 and 6 months after appliance insertion. The most frequent complaints were impaired speech, impaired swallowing, feeling of oral constraint and lack of confidence in public. A significant reduction in the number of complaints was observed between 2 and 7 days after insertion of the appliance. No further differences were revealed after longer periods of appliance wear. The type of appliance had an effect on impaired speech and swallowing. Patients' expectations of favourable treatment performance and appreciation of dental aesthetics were predictive of reported feeling of oral constraint and lack of confidence in public. There was a relationship between the complaints and acceptance of the appliance, as well as between lack of confidence in public and compliance with treatment. The results of this study highlight the importance of patients' attitudes to treatment and of functional and social discomfort associated with appliance wear for the theory and practice of the management of orthodontic patients, and the necessity for early intervention by clinicians. (+info)
(8/85) Class II correction-reducing patient compliance: a review of the available techniques.
The correction of Class II malocclusions has been hampered by the use of appliances which require the patient to co-operate with headgear, elastics, or the wearing of a removable appliance. 'Non-compliance therapy' involves the use of appliances which minimize the need for such co-operation and attempt to maximize the predictability of results. This article reviews and describes the types of appliances used, and their mode of action-based on the current available research. (+info)