Biomedical subjects
Publications and source records attributed to B Melsen.
A study of children in northern Italy finds positive but complex relationships between malocclusion and both respiration and swallowing patterns.
An understanding of the anatomy and postnatal development of the pterygomaxillary region is needed as a basis for timing and completion of Le Fort osteotomies. The present study included a macroscopic and microscopic study of human skull and autopsy material, both materials representing different developmental stages. Finally, Le Fort I procedures were completed on adult cadavers and the pterygomaxillary region studied histologically. The skull material demonstrated an increasing association between the palatine bone and adjacent bones. Disarticulation was possible only in the infantile period; in the late juvenile and the adolescent stages, disarticulation was accompanied by fractures of the heavily interdigitated osseous surfaces. The histological studies confirmed the marked complexity of the suture, and our findings suggest that the palatine bone acts as a buffer between these areas with their differing intrinsic growth patterns. The remodeling processes in the area seem to reflect different functional demands of the bony pharynx and the maxillary complex. These findings, in conjunction with the significant variations in the gross anatomy of the pterygomaxillary area combined with the location of the actual osteotomy in simulated Le Fort I procedures, force consideration of placement of the posterior osteotomy through the maxillary sinus rather than through the pterygomaxillary fissure in adults. If Le Fort procedures are to be completed in children, probable interference in facial growth is of major concern. Therefore the timing of Le Fort procedures before adolescence must be reconsidered.
The relationship between the presence of malocclusion and maintenance of teeth in adulthood was studied in a randomly drawn sample of 499 35-44-yr-old Danes. Maintenance of teeth in the past was expressed through the number of teeth present, attachment level and information of regularity of dental visits. Maintenance at present was expressed as caries present, plaque and gingivitis. The relationship of these parameters to the presence of a malocclusion symptom was analyzed directly and the indirect influence was studied through the influence of a subjectively perceived malocclusion and its impact on satisfaction. It appeared that satisfaction was significantly related to maintenance of teeth and to a positive dental behavior. A perceived malocclusion was shown to have a negative influence on satisfaction and thus indirectly on maintenance. If a public orthodontic service is aiming at lifetime maintenance of teeth, malocclusions leading to dissatisfaction with teeth and a subjectively perceived need should be taken into consideration when ranking children with regard to treatment priority.
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Intrusion has been regarded as a very controversial topic in the orthodontic literature. Although it seems a logical way to handle deep overbite in adult patients who have elongated teeth, reports on iatrogenic damage have led to the suggestion of alternative methods. Considering the disadvantages of these alternatives, it seems reasonable, however, to improve our knowledge of tissue reaction as related to intrusion. Three Macaca fascicularis monkeys were used for the experiment. By means of a segmented arch approach, the upper incisors and the four first premolars were submitted to forced eruption for 8 weeks followed by 12 weeks of intrusion. A split-mouth technique was used to study the influence of oral hygiene on the tissue reaction. On the right side of the mouth, the teeth were brushed with chlorhexidine three times per week. On the left side, no oral hygiene was performed. After intrusion of the teeth, a 1-to-14 day retention period with passive appliance preceded the killing of the monkeys. A buccolingual hematoxylin- and eosin-stained serial section was produced, and soft- and hard-tissue reactions described. It appeared that the hygiene program could limit but not prevent gingival inflammation. There was, however, a marked difference in the histologic picture of the marginal bone on the two sides. On the hygiene side, clear signs of bone deposited during forced eruption were still present. This was not the case on the nonhygiene side. The extension of bone resorption was also different on the two sides.(ABSTRACT TRUNCATED AT 250 WORDS)
Hemifacial microsomia causes asymmetry of the face frequently known to progress throughout the postnatal development if not submitted to any kind of treatment. According to the theoretic basis for treatment of hemifacial microsomia as presented by Harvold and associates, generation of the right muscle-bone interaction constitutes the necessary precondition for the bone apposition that produces facial symmetry. This theory was the basis for the treatment of three patients with abnormal condyles, one suffering from hemifacial microsomia, one patient with a unilateral condylar fracture followed by displacement and secondary resorption of the condyle, and one patient with bilateral loss of condylar cartilage as a result of trauma. The patients were treated with an activator a.m. Harvold, and the treatment results analyzed radiographically and clinically. The results demonstrated clearly that generation of an altered muscle balance is possible even though hemifacial microsomia patients suffer from absence of normal muscles--that is, normal functional matrix as well as absence of normal condyle--and that bone apposition required for establishment of symmetry can be achieved if the right microenvironment is established. It was, however, also obvious that treatment should be initiated as early as possible because the treatment result was dependent on both the timing and the cooperation of the patient.
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In the evaluation of the success of orthodontic treatment, an analysis of posttreatment changes was essential. Twenty-eight patients with increased overjet and overbite, a high mandibular plane angle, and perioral dysfunction had been treated by means of normal maximal restriction of maxillary development. The posttreatment changes of the skeletal morphology was analyzed and related to both pretreatment morphology and treatment-produced changes. The correlation analysis demonstrated that less than 25% of the variation in posttreatment changes could be accounted for by pretreatment morphology. However, the dependency of posttreatment changes on treatment-produced changes was stronger with regard to both linear and angular measurements. Upon analyzing the changes in mandibular prognathism during and after treatment, all combinations of downward and forward growth were presented. In some cases the increase in prognathism during treatment would continue after treatment; in others the reverse was true. Opening of the Y axis would in some cases be constant, leading to a decrease in mandibular prognathism. In others a pronounced anterior rotation moved the pogonion forward following treatment. A dental relapse as a consequence of skeletal relapse was seen only in cases in which normal perioral function, including normal lip closure and absence of tongue-thrust swallowing, had not been established.
The control of vertical development, in particular in the maxillary molar region, has often been suggested as a method of implementing sagittal change in treatment of Class II skeletal discrepancies. A group of twenty-eight Italian children in the early mixed-dentitional stage, with increased overjet and distal molar relationship, were treated orthodontically with a combination of a removable maxillary splint and high-pull extraoral traction. While only slight dorsal repositioning of the maxilla could be observed, an effective retardation of the vertical maxillary development was recorded, as well as a pronounced forward displacement of the mandibular symphysis. Distal movement of the maxillary dentition contributed likewise to the elimination of overjet observed clinically. The center of mandibular rotation was evaluated for each patient and displayed a pronounced variation illustrating different responses to the same type of appliance by different patients. The clinical implications of the above findings are discussed, and the necessity for constant appraisal of results during treatment is stressed.
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