Biomedical subjects
Publications and source records attributed to P J Wisth.
The present article describes a new product for long-term retention of the lower dental arch. The LingLock is a fixed bonded retainer from canine to canine in the lower front made up of separate, but co-working retention elements in the ceramic material aluminium oxide (Al2O3). The LingLock retainer enables the patient to floss the teeth in a regular manner in the actual retention area.
The aims of this study were to assess the relationship between occlusion, satisfaction with dental appearance, and self-esteem at the ages of 11 (T1) and 15 years (T2), and to study perceived treatment effects. Separate questionnaires were completed by children and their parents to determine their attitude. The dental casts of 224 children were collected at T1 and T2, and assessed by the Aesthetic Component (AC) and Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN), and Peer Assessment Rating (PAR) Index. At T2, 16 children had been treated with removable and 51 with fixed appliances, while 157 were untreated. The children in the fixed appliance group had better dental aesthetics (AC) and occlusion (DHC) than those in the two other groups. Average PAR score reduction was 71.6 per cent (T1-T2) and satisfaction with own or child's dental appearance increased significantly. The untreated group showed increased malocclusions. In spite of that, the children expressed higher satisfaction with their own dental appearance at T2 than at T1, while the parents' satisfaction level was unchanged. For the total group, orthodontic concern at T1, AC at T2, and gender accounted for 18.0 per cent of the variation in the children's satisfaction with their own dental appearance. Parents' concern at T1 and AC at T2 accounted for 32.2 per cent of the variation in parents' satisfaction. Improvement in self-esteem from 11 to 15 years was not correlated with treatment changes. A gender difference was found. The answers to the questionnaire indicated that both children and parents rate pleasant aesthetics as an important factor for psychosocial well being.
The aims of the study were to evaluate the attitude towards orthodontic treatment among 11-(T1) and 15-year-old children (T2) and their parents, to present the distribution of referral rate and treatment uptake by a treatment need index assessed at T1 and to elucidate factors influencing the decision about orthodontic treatment in the period from T1 to T2. A group of 359 children and their parents answered separate questionnaires at T1, and 293 families responded to a follow-up study 4 years later. For the clinical examination, 224 children participated after exclusion of children in active treatment. The dental study casts were assessed by the Index of Orthodontic Treatment Need (IOTN). The mean referral rate was 56%, with a variation from 40% to 71% among different dental clinics. About 44% of the children had completed or were undergoing orthodontic treatment at T2. No significant sex differences among referred and treated children were discovered. Aesthetic motives were the most frequently reported subjective reason for orthodontic care. The untreated group expressed diminishing treatment desire in the follow-up period. The logistic regression analysis selected Dental Health Component (DHC) grades as a strong predictor for treatment uptake, followed by parents' concern and attitude to braces, while the 11-year-olds' own orthodontic concern was less significant. Children in the untreated group with late treatment decisions (T2) were best predicted by Aesthetic Component (AC) changes from T1 to T2. The results indicate that dentists play a key role in determining orthodontic treatment levels. High referral rates secured low risk of denying care to some patients. Treatment decision may be guided by the orthodontist. However, individual variation in attitude and desire influence treatment uptake even among children with great need.
To assess the outcome of orthodontic treatment, 224 cases treated in a postgraduate clinic were evaluated. Pre-treatment (T1), post-treatment (T2) and 5-year follow-up (T3) study casts were assessed by the Peer Assessment Rating (PAR) Index. The influence of various factors upon treatment and long-term outcome was analysed. According to the PAR Index, orthodontic treatment reduced the malocclusions on average by 76.7 per cent, and at follow-up the reduction was 63.8 per cent. Follow-up stability was good for 76.3 per cent of the cases. Some cases (4.0 per cent) even improved, while moderate to severe post-treatment relapse occurred in 19.7 per cent of the cases. Orthodontic treatment changed Angle Class I, II and III malocclusions to near ideal occlusion (PAR scores 4.4-6.8). No long-term interaction between the groups was discovered. Sex and extraction/non-extraction treatments did not significantly affect the results. The initial PAR score accounted for 77.8 per cent of the variation in treatment PAR score change (T1-T2), and for 61.8 per cent of the variation of long-term PAR score change (T1-T3). Age at treatment start accounted significantly for the variability of treatment changes (P < 0.001). The PAR score at the end of treatment had some explanatory importance (R2 = 0.099) for the long-term (T1-T3) result. However, PAR score changes in the follow-up period were difficult to predict.
The prevalence of different malocclusion features was investigated in 396 6-year-old Icelandic children, using the epidemiologic registration method described by Björk et al. in 1964. Girls were ahead of boys with regard to dental stage (P < 0.01). One or more permanent teeth were congenitally missing in 5% of the children. Postnormal occlusion was found in 27% of the boys and in 31% of the girls, and prenormal occlusion was found in 6% and 5%, respectively. Straight terminal plane at the second deciduous molars was found in individuals with either normal or postnormal occlusion. Thus, it can be misleading to use the relation of the terminal planes as a measurement of the sagittal relation between the jaws. The prevalence of hypodontia was much lower than has been reported previously for Icelandic children.
The aims of the study were to relate patient satisfaction and perceived psychosocial benefit to professional assessed treatment and long-term outcome. Questionnaires were mailed to 250 patients treated previously in a postgraduate clinic. The response rate was 79%, and the mean age was 28.3 years. Professionally defined outcome was assessed according to the Index of Orthodontic Treatment Need (IOTN) and the Peer Assessment Rating (PAR) index applied to dental casts at the start of treatment (T1), at the end of active treatment (T2) and 5 to 10 years out of retention (T3). Data from 177 cases were used in comparison analysis between patients' and orthodontists' assessments. There was high patient satisfaction with dental appearance (87.0%) and treatment results (77.4%). The aesthetic component of IOTN at T2, PAR score at T3, extraction/non-extraction, pre-treatment concern for dental appearance, sex and treatment time accounted for 33% (R2 = 0.33) of the variability of satisfaction with own dental appearance. Explanatories for self-perceived psychosocial benefit of treatment were pre-treatment concern for dental appearance, aesthetic component at T1 and T3 and PAR score at T3, (R2 = 0.22). Stepwise logistic regression analysis selected change in upper anterior segment (T3-T2) as the most important component of PAR index features for grouping satisfied and dissatisfied individuals (Odds ratio = 0.65) together with satisfaction with own dental appearance (Odds ratio = 7.28). The results indicate some discrepancies between professionally assessed outcome and patient satisfaction and perceived psychosocial benefit. The aesthetic component was a stronger indicator for patient satisfaction and perceived benefit than the PAR index.
The aims of the study were to compare the opinions of both the children and the parents with an orthodontist's assessment of treatment need, to investigate the children's self-esteem, and parents' opinion of treatment results. The study group of 359 children (51% girls, 49% boys, mean age 10.6 years) and their parents were asked about their opinions in separate questionnaires. The self-esteem of the children was measured by the global negative self-evaluation scale (GSE). An orthodontist assessed the children's dental casts with the index of Orthodontic Treatment Need (IOTN). Allocated to the dental health component (DHC) of IOTN, 53.2% children had very great to moderate need and 46.8% had little to no need. No sex difference was noted. The children's own assessments of the aesthetic component (AC) of IOTN were closer to the attractive end of the scale than the orthodontist's (p < 0.05). Desire for treatment was more frequent than dissatisfaction with children's occlusion (p < 0.001). The patients' orthodontic concern correlated significantly with both DHC and AC grades (p < 0.001). The children's GSE scores were not correlated to components of IOTN. For children with very great need, high self-esteem was related to orthodontic concern. The parents (90.8%) perceived dental esthetics to be equally important for girls and boys. Most parents (93.0%) thought the results of orthodontic treatment were good. The results indicate meaningful association between orthodontic concern and orthodontic treatment need assessed by IOTN. However, some patients with great need do not express orthodontic concern, whereas others with near ideal occlusion express concern.
The craniofacial morphology of 33 Turner syndrome patients, aged 7-16.7 years, was evaluated by standard cephalometric methods. The sample was subdivided according to karyotype and 72 normal girls aged 7.1-16.1 years served as controls. The size of the calvarium and face was generally smaller in the Turner group than in the controls. The morphology was characterized by a flattened cranial base angle, a marked reduction in posterior cranial base length, facial retrognathism and short and posteriorly rotated jaws. The same morphological pattern was found in all the karyotypes, but the deviations were most pronounced in monosomy X (45X) patients. The results indicate that a deviating pattern of craniofacial size and morphology has already been established in childhood. It is suggested that the deviations originate in the fetal period, when the primary cartilages form the craniofacial skeleton.
Forty-five patients with mandibular retrognathism treated by surgical mandibular advancement by sagittal split osteotomies were evaluated cephalometrically before treatment at the intermaxillary fixation release, and 6 months postoperatively. The treatment resulted in appreciable improvement of the mandibular retrognathism, and the facial morphology was changed positively toward normal values. The mandibular prognathism was accomplished by an anterior displacement of the mandibular corpus and by a slight increase of the mandibular corpus length. The anterior facial height and the mandibular plane angle were increased by a clockwise rotation of the anterior segment and a counterclockwise rotation of the posterior segment, which consequently increased the gonial angle. These changes partly reversed during the postfixation period. Dentoalveolar changes were found in the position of the maxillary and mandibular incisors; both were uprighted, the mandibular incisors more than the maxillary incisors. In general, the long-term positive effects of the surgical mandibular advancement revealed great stability.
The forces required to debond orthodontic brackets on human teeth were studied in vitro. The brackets were bonded with different glass ionomer cements (GICs), and a composite resin (Concise). The shear force required to remove the brackets was recorded at different time intervals after bonding. The bond strength was considerably lower for the GICs compared with brackets bonded with the composite resin, at all time intervals that were studied. Moreover, the bond strength increased more slowly for the GICs compared with the resin. Different GICs displayed a varying setting time. The bonding strength of GICs increased more than 50 per cent between 10 and 20 minutes setting time.
The prevalence of different malocclusion features was investigated in 500 14-yr-old male Saudi Arabian children, using a modification of the registration method described by Björk et al. (3). Most of the children were in dental stage DS4 (all permanent teeth anterior to the first molars erupted). Totally 62.4% of the children had one or more malocclusion features related to dentition, occlusion, or space. The treatment need was evaluated according to the guidelines used in the Norwegian Health Service. About 40% were found to need treatment with fixed appliances, and for 33% extraction of permanent teeth would be part of the treatment. Only about 2.5% would benefit from treatment with simple removable appliances.
Malocclusions are generally less common among African and Arab children than Europeans. This difference may be due to racial as well as external and environmental factors. Angle CI. III malocclusion is, however, more common among African and Arab children than in Europeans, whereas the opposite is found for Angle CI. II malocclusions. Space conditions are better in African and Arab than in European populations. The aim of the study was to assess the prevalence of malocclusion in 12 year old Sudanese children using the method for epidemiological registration devised by Björk, Krebs and Solow. The majority of the children had Angle CI. I (normal and malocclusion), followed by CI. II and CI. III malocclusion. Sagittal, vertical and transversal occlusal anomalies were not common. The number of the abnormal conditions found in the survey suggests that public awareness and preventive orthodontics are important fields when the future orthodontic service in Sudan is organized.
Following the extraoral vertical subcondylar osteotomy in the correction of the highly asymmetric and prognathic mandible, only insignificant radiographic changes were observed in the temporomandibular joint 12 months postoperatively. Slight morphologic alterations of the condylar seating were demonstrated at occlusion, but there was no significant difference in condylar position between the two sides of the surgically corrected asymmetric mandible. The condylar axis did not deviate from the preoperative situation, and condylar axis did not deviate from the preoperative situation, and condylar mobility was fully resumed 12 months postoperatively. The extraoral vertical subcondylar osteotomy procedure is applicable in the treatment of combined mandibular asymmetry and prognathism and does not create morphologic changes that differ in the two temporomandibular joints.
A cephalometric analysis of the positional changes of the mandible and the upper and lower incisors following vertical subcondylar ramus osteotomy was performed on 80 patients. The patients were prognathic without laterognathism or open bite and all the patients had preoperative orthodontic treatment. 40 patients were operated with an intraoral (IVSO) and 40 with an extraoral approach (EVSO). Both groups showed postoperatively posterior rotation of the mandible, shortening of the posterior facial height, increase in anterior facial height and extrusion of the incisors in both jaws. A significantly greater reduction of posterior facial height was observed in the EVSO-group, but otherwise the 2 groups did not reveal any statistically significant positional differences. The material was sub-divided into 2 groups 1 with (n = 32) and one group without (n = 48) extra skeletal (nasomandibular) fixation in addition to the intermaxillary fixation. Significantly less positional changes of the incisors and less increase of anterior facial height was found in the group with skeletal fixation, but the influence on other skeletal alterations was limited. After release of the intermaxillary fixation, the only difference between the groups was intrusion of the earlier extruded incisors, most pronounced in the group without skeletal fixation.
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The intention of this work was to study the dentoalveolar and basal jaw changes in a group of children (aged 5-10 years) with nonforced anterior crossbite treated with maxillary protraction from a face mask and to compare the changes with those found in a control group with normal dentoalveolar and basal maxillomandibular relationship. The data were obtained from lateral cephalograms of 22 children taken before treatment, after a treatment period of 3-12 months, and after an observation period of 6-48 months. A group of children (n = 40) with normal maxillomandibular relationship served as controls. During treatment the mandibular prognathism was reduced, and a positive overjet was established in 18 children. The changes during the observation period were generally comparable to those found in the control group, and thus indicated a very small relapse tendency. The posttreatment comparison of the groups showed fewer significant differences than before treatment, indicating that the treatment had a normalizing effect not only on the negative overjet but also on the general face morphology.