British journal of orthodontics最新文献

This retrospective study reports the incidence of infants born with the cleft lip and palate anomaly within the Edinburgh Cleft Units catchment area, between 1 January, 1971, and 31 December, 1990. The importance of accurate data collection for local, regional, and national data bases is discussed with reference to the recent CSAG report on cleft lip and palate services in the UK. Five-hundred-and-two cleft lip and palate patients were identified (291 males, 211 females). The incidence is reported as 1.4 per 1000 live births (1 in 711). Twenty-five per cent of clefts affected the primary palate, 45 per cent affected the secondary palate, and the remaining 30 per cent were clefts of both the primary and secondary palate. Overall, a higher percentage of males were affected (58 per cent males to 42 per cent females). Clefts of the secondary palate, however, were more common in females (56 per cent females to 44 per cent males). Data presented in this study is similar to that previously reported from UK centres. It is suggested the accuracy of the UK cleft lip and palate data collection needs to be improved. Prospective data collection in a standardized format carried out on a national basis has to be a priority as recommended by the CSAG report.

The objective of this paper was to compare distortion of the tie wings and bases of metallic orthodontic brackets following clinical use and after debond by either of two methods, and took the form of a prospective random control trial. Five-hundred-and-seven brackets were debonded using either bracket removing pliers or a lift off debonding instrument (LODI). By a system of random allocation contralateral opposing quadrants were debonded with a 0.019 x 0.025-inch archwire either in place or removed. After debond brackets were tested for slot closure by the fit of rectangular test wires from 0.016 x 0.022 to 0.021 x 0.025 inch in size. The LODI produced few slot closures sufficient to affect the fit of all but the largest test wire. Bracket removing pliers used after removal of the archwire produced significantly greater numbers of distorted brackets in response to testing with all but the largest wire. With the 0.021 x 0.025 inch wire in place the presence or absence of the archwire at the time of debond made no difference to the number of slot closures. Ten per cent of the brackets debonded using bracket removing pliers had distorted bases, no base damage was produced by the LODI. The use of bracket removing pliers at debond caused significantly more slot closures than use of the LODI. When bracket removing pliers are used the archwire should be left in place at the time of debond since this reduces the number of distortions.

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.

This article presents a modified activator for treatment of open bite cases. The intermaxillary acrylic of the lateral occlusal zones is replaced by elastic rubber tubes. By stimulating orthopaedic gymnastics (chewing gum effect), the elastic activator intrudes upper and lower posterior teeth. A noticeable counterclockwise rotation of the mandible was accomplished by a decrease of the gonial angle. Besides the simple fabrication of the device and uncomplicated replacement of the elastic rubber tubes, treatment can be started even in mixed dentition when affixing plates may be difficult.

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.