The influence of lip function on the sagittal and transversal development of the maxilla in cleft patients.

Cleft patients who have undergone surgery often show considerable inhibition in the sagittal development of the mid-face after completed growth. This is partly attributed to scar contraction in the lip region following surgery. The present investigation deals with the etiological factors involved in the development disturbances caused by the cleft in the maxilla of 100 cleft patients. Particular attention was paid as to the unfavourable effect of the operated cleft lip. This was tested electromyographically and correlation between the electromyographic and the skeletal measurements was sought. Electromyographic changes in lip activity during orthodontic treatment was also investigated. The effect of these changes is discussed.

Clinical application and effects of the Forsus spring. A study of a new Herbst hybrid.

BACKGROUND: The best known of the fixed functional appliances are the Herbst appliance and the Jasper Jumper. The Forsus spring is a new development which has been tested in a clinical study to establish when it can be used and to compare it with its predecessors. PATIENTS AND METHOD: The Forsus spring was used over a period of 4 months to treat 13 patients with an average age of 14.2 years with Class II malocclusion. RESULTS: Evaluation of the lateral cephalograms showed that dental effects accounted for 66% of the sagittal correction. The sagittal occlusal relations were improved by approximately 3/4 of a cusp width to the mesial on both the right and left side as a result of distal movement of the upper molars and mesial movement of the lower molars. Retrusion of the upper and protrusion of the lower incisors reduced the overjet by 4.6 mm. Intrusion and protrusion of the lower incisors reduced the overbite by 1.2 mm. The occlusal plane was rotated by 4.2 degrees in clockwise direction as a result of intruding the lower incisors and the upper molars. The maxillary and mandibular arches were expanded at the front and rear during treatment.--Evaluation of a questionnaire filled in by the patients after 2 months of treatment showed that approximately half of them had experienced difficulties in brushing their teeth. The main problem, however, was the restriction experienced in the ability to yawn. Overall, two thirds of the adolescents found the Forsus spring better than the appliance previously used to correct their Class II malocclusion, such as headgear, activator or Class II elastics. CONCLUSION: The Forsus spring has stood the test in clinical application. It is a good supplement to the Class II appliance systems already available.

New clinical applications for the Jasper Jumper.

This article describes the use of the Jasper Jumper in the treatment of class III anomalies, both theoretically and with a case report. Contrary to its use in class II anomalies, the Jasper Jumper is fixed to the 6-year-molars in the lower jaw and in the canine area in the upper jaw. This results in a continuously working mechanism--independent of co-operation on the part of the patient.

Malocclusion and the need for orthodontic treatment in 9-year-old children. Survey based on the Swedish National Board of Health and Welfare Scale.

In this study the prevalence of malocclusion and the need for orthodontic treatment was studied in 1,020 children (541 boys and 479 girls). At the time of examination they were between the ages of 8 years 5 months and 9 years 5 months. The frequency of dental, space and occlusion anomalies was recorded and compared with those in other studies. The need for orthodontic treatment was judged according to the 5-point scale of the Swedish National Board of Health and Welfare (1996). In 32% of the children there was an urgent need for treatment (Grade 3 and 4) in a further 32% treatment would be desirable (Grade 2). There was a little need for treatment (Grade 1) in 24% and no need (Grade 0) in 12%.

Long-term stability of treatment results after upper jaw segmented osteotomy according to Schuchardt for correction of anterior open bite.

Upper jaw osteotomy according to Schuchardt is a relatively rarely performed surgical procedure due to its narrow range of indications. Within the framework of a clinical follow-up examination using this method, we studied the long-term results in 26 patients, employing cephalometric analysis and analyzing the clinical findings. The results of this study show that the outcome of the operative correction of anterior open bite remained largely stable. Although partial relapse occurred in 3 cases (= 11.5%), there was a significant functional and esthetic improvement in comparison with the preoperative initial findings. When indicated, upper jaw osteotomy according to Schuchardt is thus a suitable surgical technique for correction of anterior open bite.

In vivo effectiveness of enamel sealants around orthodontic brackets.

OBJECTIVE: In this randomized study, the caries-protective effect on vestibular enamel of two fluoride-containing sealants (Protecto® and Light Bond®) during multibracket treatment was investigated. MATERIALS AND METHODS: In all, 40 orthodontic patients about to receive a multibracket appliance with the brackets bonded to the vestibular tooth surfaces were randomly included in this study. Each one was randomly assigned to one of four groups. A crossover design was selected in which a sealed quadrant was contralateral to an unsealed quadrant, then choosing the reverse configuration in the opposite jaw. Two sealants were, thus, tested on vestibular enamel on left and right anterior teeth and premolars in both jaws of each patient over 6 months of multibracket treatment. A DIAGNOdent® pen measuring laser fluorescence was used to analyze the relevant enamel surfaces both at baseline and after 6 months. RESULTS: Neither the incidence nor the characteristics of the demineralization we observed during the study differed between the 4 groups. CONCLUSION: Single application of smooth-surface sealants did not protect enamel around brackets from incipient carious lesions during the first 6 months of multibracket treatment.

[The age dependence of the tissue reaction in tooth movements]. / Die Altersabhängigkeit der Gewebereaktion bei Zahnbewegungen.

Factors are indicated that influence orthodontic tooth movement and vary with age of life. During a first phase, tooth movement is characterized through biomechanical properties of the periodontal ligament and alveolar bone, while during a second phase, through kind and extent of disturbance of periodontal blood circulation. During a third phase of tooth movement, remodelling and repair is determined by cellular kinetics, synthesis, and mineral turnover. Reports in the literature and our own experimental findings are interpreted. In conclusion, in middle aged patients the remaining biological possibilities for tooth movement are decreased to about one third of those to be found in infants.

[Changes in clinical crown length during multiband treatment]. / Die Veränderung der klinischen Kronenlänge unter Multibandbehandlung.

The clinical crown lengths of the incisors and first molars of 50 adolescents were measured on dental casts prior to and five to seven months following end of treatment and the differences were recorded. The patients were treated with fixed appliances for an average of 23 months. In addition, initial crown lengths were compared to those of ten children who were four years younger on average. Treatment time and objectives were recorded. Statistically significant differences were determined by means of the t-test. In order to test for correlations between treatment objectives, duration of treatment and change in clinical crown length, correlation analysis was used. The results were: clinical crown length increases physiologically from ten to 14 years of age by about 0.175 mm per year. During fixed appliance therapy in adolescents, the clinical crown length increases. This is accelerated when employing extrusive mechanics, whereas intrusive mechanics reduce this tendency. There is no evidence to suggest that the process is accelerated by the type of appliance.

[The importance of the center of resistance for the biology of tooth movement]. / Die Bedeutung des Widerstandszentrums für die Biologie der Zahnbewegung.

The tooth movement of loaded premolars was investigated in four two-years-old beagle dogs under general anesthesia. Two supragingival registrations were performed to calculate the center of rotation in order to estimate the amount of tipping. Loads of 5 to 20 N were applied for two to four seconds. The amount of tipping was found to be load- and time-dependent. The discrepancy between these findings and the models of analytical mechanics were explained by bone bending in our experiments. Biology and localization of periodontal remodelling is supposed to be dependent on load magnitude, load duration and physical properties of all periodontal tissues including bone.

[Force-moment measurements on the passive palatal arch under the influence of the tongue]. / Kraft-Moment-Messungen am passiven Palatinalbügel unter dem Einfluss der Zunge.

Forces and moments, which the tongue transmits during swallowing to transpalatinally combined first upper molars, were measured in vivo. Three basic forms of the transpalatal arch were studied: one without an additional bend, one with a horse shoe bend facing the mesial, and one with a bend towards the distal. Regardless of which kind of palatal arch was used, tongue function caused intrusive, expansive and mesial directed forces. Using the arch form without an additional bend evoked both a mesial and a distal tipping moment. The arch form with the bend facing the mesial caused a mesial tipping moment during swallowing. When the horse shoe bend faced the distal, a distal directed moment predominated. For this reason in cases involving a problematical anchorage situation, a transpalatal arch with a horse shoe bend facing the distal should be employed.

[Orthodontic surgical treatment of class III--the electromyographic effects on the masticatory and facial musculatures]. / Kieferorthopädisch-chirurgische Behandlung bei Klasse III--elektromyographische Effekte auf Kau- und Gesichtsmuskulatur.

22 adult class-III patients, partly with considerable vertical excess, who required combined orthodontic-surgical treatment were investigated at the end of preoperative orthodontic treatment and six months postoperative. EMG activity was recorded for the m. temporalis, m. masseter, perioral and the floor of the mouth muscles during rest position and in six different active functions. Postoperative activities revealed a significant reduction for most muscles in almost all functions. Additionally right-left differences were reduced. This effect is regarded to be a sign of more efficient muscular action due to improved biomechanical and occlusal conditions so that defined functions can be exerted by less muscular activation.

[Apical root resorption during orthodontic treatment]. / Die apikale Wurzelresorption unter kieferorthopädischer Behandlung.

Pre- and posttreatment radiographs of 2050 orthodontically treated patients were examined and apical root resorptions of more than 2 mm were identified. 30 patients (211 teeth) were affected. Treatment characteristics and objectives of this group (with severe apical root resorption) were compared to a treated group of 30 patients (with no resorption) to determine clinical risk factors. Extrusion, but especially jiggling and a long treatment period were found to be significantly more frequent in the group exhibiting resorption than in the control group. Pathogenesis of treatment-induced root resorption is discussed in respect to histological results.

Position of anterior teeth following surgical correction of prognathism.

20 patients who had all undergone surgical correction of progenia by sagittal split operation in the ascending ramus were chosen for a follow-up investigation 5 years after the operation. The patients could be divided into two groups showing either horizontal or vertical facial growth pattern. A cephalometric analysis was made of all the patients and the results of both groups were compared with one another. In particular the changes in the position of the anterior teeth and the amount of sagittal and vertical relapse were noted. It was noticed, that the type of measurable postoperative relapse was different in the two groups. Postoperative mandibular relapse is partially compensated by the position of the anterior teeth. Therefore the postoperative changes in the position of the anterior teeth are different in the two groups.

Experience with sagittal splitting of the horizontal ramus in mandibular prognathism.

Intra-oral sagittal splitting of the horizontal mandibular ramus is only possible to a limited extent in the treatment of patients with mandibular prognathism and a deep overbite. However, this operation has given stable results up to 3 years postoperatively in cases of prognathism with open bite.