Thin-plate spline analysis of treatment effects of rapid maxillary expansion and face mask therapy in early Class III malocclusions.
(1/98)
An effective morphometric method (thin-plate spline analysis) was applied to evaluate shape changes in the craniofacial configuration of a sample of 23 children with Class III malocclusions in the early mixed dentition treated with rapid maxillary expansion and face mask therapy, and compared with a sample of 17 children with untreated Class III malocclusions. Significant treatment-induced changes involved both the maxilla and the mandible. Major deformations consisted of forward displacement of the maxillary complex from the pterygoid region and of anterior morphogenetic rotation of the mandible, due to a significant upward and forward direction of growth of the mandibular condyle. Significant differences in size changes due to reduced increments in mandibular dimensions were associated with significant shape changes in the treated group. (+info)
Elastic activator for treatment of open bite.
(2/98)
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. (+info)
Mixed dentition space analysis in a Thai population.
(3/98)
This study produced simple linear regression equations to be used for mixed dentition space analysis for males and females, and sexes pooled in a population living in northeastern Thailand. Measurements of teeth were made to within 0.01 mm on the dental casts of 215 boys and 215 girls (mean age 15.7 years). All dentitions were required to be free of any signs of dental pathology or anomalies. It was found that males had significantly larger teeth than females as represented by summations of mandibular incisor, canine, and premolar widths. ANOVA of regression indicated a close relationship between mandibular incisor summation and corresponding summations of canine and premolars. The low coefficients of determination (r2) of the regressions ranged between 0.29 and 0.42, and were higher for females than males, which might be attributable to the ethnic diversity of the sampled population. The regression equations produced predictions of mesio-distal width summations for maxillary and mandibular canine, and premolar arch segments that were slightly different from other reported Asian studies. Moyers' prediction tables at the 50th percentile were found to under-estimate tooth size summation compared with the present investigation. The predictions from simplified regression equations matched well with those of this study for sexes pooled, and for males and females separately. (+info)
Persistence of deciduous molars in subjects with agenesis of the second premolars.
(4/98)
The purpose of the present study was to investigate persistent primary second molars in a group of young people in their late twenties with agenesis of one or two second premolars. In 1982-83 it was decided, in connection with the orthodontic evaluation of 25 patients, to allow 35 primary molars (one or two in each patient) to remain in situ. All patients had mixed dentitions and agenesis of one or two premolars. The primary teeth were generally in good condition, although root resorption and infra-occlusion (compensated by occlusal composite onlays) occurred. In 1997, 18 of the 25 patients with a total of 26 retained primary molars were reexamined, comprising a clinical examination for exfoliation, extraction, loosening, and ankylosis, and a radiographic examination for root resorption, tooth morphology (crown and root), and alveolar bone contour. The examination showed that the degree of root resorption was unaltered in 20 of the 26 primary molars. In the permanent dentitions, where these primary molars persisted, there were no morphological deviations. Three of the six remaining primary molars had been extracted and three showed extensive resorption. In three of the 26 primary molars the infra-occlusion had worsened. The present study shows that persistence of primary second molars in subjects with agenesis of one or two premolars, and normal morphology of the permanent dentition can be an acceptable, semi-permanent solution for the patient. Whether this could also be an acceptable long-term solution will be shown by follow-up studies. (+info)
Survey of dental treatments for pediatric patients referred to the pediatric dental clinic of a dental school hospital.
(5/98)
This survey was conducted to clarify which dental treatments in children are regarded as difficult by general dentistry practitioners. The subjects were 615 children who first visited Tokyo Dental College Chiba Hospital from January 1995 to August 1999 with reference letters. There were 615 children in the study; 571 (92.8%) came from Chiba City where our hospital is located and the 11 regions surrounding Chiba City. The prime reasons for referral in the order of frequency were treatments of dental caries, malalignment/malocclusion, traumatized teeth, supernumerary teeth, retarded eruption/impacted teeth, abnormal direction of erupted teeth, congenitally missing teeth, prolonged retention of deciduous teeth, and abnormal frenulum. Patients with dental caries or traumatized teeth in the deciduous dentition period and those with malalignment/malocclusion, supernumerary teeth, or retarded eruption/impacted teeth in the mixed dentition period were often referred to medical organizations specializing in pediatric dentistry because of the difficulties in controlling the patients' behavior and in providing adequate treatment. The information about pediatric dental treatments considered difficult by general dentists revealed by this survey appears to be useful and needs to be incorporated in the programs for clinical training of undergraduate students and education of postgraduate students. (+info)
Rapid palatal expansion in mixed dentition using a modified expander: a cephalometric investigation.
(6/98)
The aims of this investigation were to cephalometrically study the short-term skeletal and dental modifications induced by rapid palatal expansion in a sample of 20 patients (10 male, 10 female), aged 6-10 years (mean age 8 years) in mixed dentition with a uni- or bilateral posterior crossbite, a mild skeletal Class II malocclusion, and an increased vertical dimension (FMA, SN/\GoGn), and to compare them with an untreated matched control group of 20 subjects (10 male and 10 female), mean age 8 years. Cephalometric analysis showed that the maxilla displayed a tendency to rotate downwards and backward, resulting in a statistically significant increase of the SN/\PP angle (T0 = 9*95 degrees, T1 = 11*60 degrees, P < 0*01) and the SN-ANS linear value (T0 = 49*50 mm, T1 = 51*10 mm, P < 0*05). In addition, there was a statistically significant alteration of the anterior total facial height N-Me (T0 = 113*15mm, T1 = 114*15 mm, P < 0*05) and for the dental upper molar measurement U6-PP (T0 = 19*70 mm, T1 = 20*30 mm, P < 0*05). The small alterations found in the anterior total facial height and in the sagittal angles agree with previous studies, and suggest that RPE can be also used in subjects with a tendency to vertical growth and a skeletal Class II malocclusion. (+info)
Cleft type and Angle's classification of malocclusion in Korean cleft patients.
(7/98)
This study was performed to investigate the contributing factors, such as cleft type, side of cleft, patient's age, and gender, associated with Angle's classification of malocclusion in Korean cleft patients. The records of 250 cleft patients (175 males, 75 females) who attended the Department of Orthodontics, Seoul National University Dental Hospital between 1988 and 1999 were examined. The percentages of subjects with cleft lip (CL), cleft lip and alveolus (CLA), cleft palate (CP), and cleft lip and palate (CLP) were 7.6, 19.2, 9.6, and 63.6, respectively. The overall distributions of unilateral and bilateral clefts were 76 and 24 per cent, respectively. The overall percentages of Class I, II, and III malocclusions were 18.5, 8.8, and 72.7. The frequency of Class III malocclusions was most prevalent in all age groups. Bivariate analysis showed that whilst gender was not significant, the type of cleft significantly influenced the development of a Class III malocclusion (P < 0.01). Using logistic regression analysis, subjects in the CP (P < 0.05) and CLP groups (P < 0.01) were 3.9 and 5.5 times more likely to have a Class III malocclusion than those in the CL group. There was, however, no statistical difference in the prevalence of a Class III malocclusion between the CL and the CLA groups (P > 0.05). When the degree of cleft involvement in the palate increased, so did the predominance of a Class III malocclusion. (+info)
Comparative reproducibility of three methods of radiographic assessment of alveolar bone grafting.
(8/98)
The aims of this study were to compare the reproducibility of three radiographic methods of assessing the quality of alveolar bone grafts, namely the Bergland, Kindelan and Chelsea Scales, and evaluate their application in the mixed and permanent dentitions. Additionally the use of occlusal versus periapical radiographs was assessed. Three examiners applied each scale on two occasions to the radiographs of 48 cleft lip and palate patients who had received alveolar bone grafts in 59 sites (11 had bilateral clefts). The agreement between repeated assessments by the same observer at different time points was measured by the kappa statistic, for each of the three assessors and each of the types of radiographic scale in turn. None of the three scales was found to be more reproducible than the others (kappa statistics for intraobserver variation ranged from 0.61 to 0.70). The agreement between observers was also similar across the three radiographic scales (multiple kappa statistics for inter-observer variation ranged from 0.45 to 0.51). Likewise, neither occlusal nor periapical radiographs were found to enable greater reproducibility of assessment. Surprisingly there was a tendency to greater reproducibility in the mixed than in the permanent dentition, which suggests the outcome of alveolar bone grafting may be assessed at an earlier stage than currently adopted. The outcome of alveolar bone grafting in this group of patients was generally successful. (+info)