Per Johan Wisth

Soft tissue response to upper incisor retraction in boys.

The paper describes the lip morphology and treatment changes in two groups of boys with slight (3–4 mm) and marked (8–10 mm) overjets. The results show that the initial morphological differences are greatest in the lower lip and these are maintained even after treatment. In individuals with a small overjet, the upper lip response is more closely related to the degree of incisor retraction than in individuals with marked overjet. Correction of the great overjets results in approximately similar upper and lower lip retraction. The results generally show great variability, and thus indicate that prediction of soft tissue changes in an individual case is difficult.

Frequency of hypodontia in relation to tooth size and dental arch width

This study describes the frequency of hypodontia among all the children of the same age group in a Norwegian municipality and reports variations of some dimensions of the dentition associated with hypodontia. Congenitally missing permanent teeth, not including third molars, were found in 7.1 per cent of the material at age seven, and in 6.6 per cent at age nine. The difference seemed to be due to insufficient mineralization of the second lower premolars in boys at age seven. The frequency of hypodontia per se was a little higher in girls than in boys, and the girls were missing more teeth per individual. Neither the dental arch width nor the mesiodistal diameter of the teeth were significantly different in the hypodontia group compared to a control group without hypodontia.

Prevalence of malocclusion in 6-year-old Icelandic children: A study using plaster models and orthopantomograms

The prevalence of different malocclusion features was investigated in 396 6-year-old Icelandic children, using the epidemiologic registration method described by Bjork 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.

Mandibular function and dysfunction in patients with mandibular prognathism

There are indications that in patients with mandibular prognathism there is a great risk of mandibular dysfunction symptoms. The present study was undertaken to verify this and to investigate whether surgical correction of the sagittal discrepancy would improve the functional abilities. The material comprised a group of 28 untreated patients with mandibular protrusion and another group of 44 patients who were operated on 10 years ago. The functional status and subjective symptoms were recorded according to the principles introduced by Helkimo. The results indicate a great reduction of the subjective symptoms in the treated group, and even the objective evaluation shows a reduction of the dysfunctional symptoms in the treated persons, particularly in relation to the movement capacity of the mandible. The number of occluding teeth was significantly greater in the treated persons, and the number of occlusal interferences was smaller. Thus, it seems that a repositioning of the mandible to a correct sagittal position will improve function. A normal anatomic foundation may therefore be an important factor in securing normal mandibular function.

The effect of maxillary protraction on front occlusion and facial morphology

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.

The craniofacial morphology of individuals with hypodontia

This work describes the variations in craniofacial morphology in individuals with congenially missing permanent teeth with relation to facial prognathism, jaw development and inclination of the incisor teeth. Both sexes displayed significantly less upper jaw prognathism in individuals with hypodontia compared to the controls, and a less maxillary length as well. This finding was independent of whether the congenitally missing teeth were situated in the upper or the lower jaw. The upper incisors displayed greater anterior inclination in the individuals with hypodontia of both sexes.

Changes in craniofacial morphology of individuals with hypodontia between the ages of 9 and 16

The effect of hypodontia on the general growth pattern was studied by comparing the same hypodontia group (n female = 18, n male = 12) with a control group (n female = 12, n male - 14) at the ages 9 and 16. The length of the maxilla was shorter in individuals with hypodontia, otherwise only minor differences were observed. It thus seems that hypodontia has little effect on the general growth pattern, and that orthodontic treatment in hypodontia patients should follow the same guidelines in relation to growth as in any other children.

Comparison of two surgical methods in combined surgical-orthodontic correction of impacted maxillary canines

The post-treatment periodontal condition of impacted maxillary canines was examined in two groups of patients. In one group (n =34) the teeth were exposed in the mouth after removal of the bone and soft tissue covering of the crown. In the other group (n =22) the bone covering the crown was removed, whereafter the mucoperiosteal flap was sutured back. In both groups the orthodontic treatment procedures were basically the same. The mean treatment duration was 18 months after radical surgical exposure and 22 months after moderate surgical exposure. The teeth were examined 1-2 years after removal of the fixed appliances. Oral hygiene and gingival inflammation were approximately the same in both groups. The palatal pocket was deeper on teeth subjected to moderate surgical exposure, and the depth also varied more. The loss of fiber attachment was not significantly different except on the palatal surface, where it was greater after radical exposure and also varied more. The interdental bone height, which was measured on radiographs, varied more after radical than after moderate surgical exposure.

Radiographic changes in the temporomandibular joint subsequent to vertical ramus osteotomy

The position of the mandibular condyle in patients treated for mandibular protrusion by the oblique vertical osteotomy of the mandibular rami was studied on temporomandibular joint radiographs exposed according to the oblique transcranial projection. Forty-four adults participated in the study, and the radiographs were taken before the operation, 6 weeks postoperatively and 1 year postoperatively. At the 6-week postoperative control all the variables measured indicated a significant downward and forward displacement of the condylar fragment of about 1mm. The changes did not increase the variability of the joint morphology. At the 1-year postoperative control there were still significant differences in the position of the condyle compared with the pretreatment recording. A slight tendency to normalization was, however, observed. The mobility of the condyle, which was greatly restricted at the 6-week postoperative control, was fully restituted 1 year after the operation.

Integumental profile changes caused by surgical treatment of mandibular protrusion

Abstract The soft tissue profiles of 16 women with mandibular protrusion were compared to a group of normals before and after surgical correction. The evaluation was based on lateral cephalo-metric radiographs. The upper lip morphology was generally similar in protrusion individuals and normal controls, except for a somewhat shorter lip length in the protrusion group. The lower lip was characterized by a shallow lip sulcus and an obtuse lip-chin angle. Surgical correction resulted in a lengthening of the upper lip, and a deepening of the lower lip sulcus, which normalized the lip morphology. The lip position in relation to the E-line was, however, not fully corrected.