Tandlaegebladet最新文献

Because of the many drawbacks of the hard and brittle material, ceramic brackets should not be used uncritically for orthodontic treatments. If ceramic brackets are used, the following guidelines should be observed: 1. If large and complicated tooth movements are involved, conventional bracket systems should be considered. 2. Occlusion on ceramic brackets is to be avoided. 3. Sharp instruments should be used with extreme care to avoid scratching the ceramic surface. Metal ligatures must not be used. 4. The length of the treatment is extended, probably because of the increased friction. 5. The problems connected with removing the brackets have not yet been solved. Be particularly careful of weakened teeth. 6. Esthetically, ceramic brackets function satisfactorily, but transparent elastic ligatures do not. They rapidly become discoloured and need frequent replacement. Nor are there as yet any "invisible arch wires", apart from some few, extremely flexible "white" arch wires. The ceramic bracket has no doubt come to stay, but there have been many difficulties in the "running-in" period, and the problems are far from solved yet. New ceramic brackets are coming onto the market all the time, and only future clinical studies can show whether they will become a genuine alternative to the conventional bracket.

Variations in facial growth and dentoalveolar development were studied in a group of 40 patients treated with the Teuscher appliance, a functional appliance which is a combination of an activator and a high-pull headgear. Patients were selected for this study on the basis of an initial Class II Division 1 malocclusion and on being consecutively treated with this appliance. The results showed that in 80% of the patients the maxilla either remained unchanged in it's relationship to the anterior cranial base (NSL) or became more retrusive during the treatment period. The mandible in 70% of the patients became more prognathic, only in four cases did the mandible become slightly more retrognathic. The analysis further showed that no statistically significant change occurred in the inclination of the mandible during treatment. Correlation analysis of the association between pretreatment mandibular plane angle and the changes during treatment showed no association. The dentoalveolar changes were characterized by retroclination of the maxillary incisors in 90% of the patients which occurred in spite of the torque springs, intended to maintain the inclination of these teeth. In contrast, the mandibular incisors on average showed no statistically significant change during treatment. This may be attributed to the capping of these teeth. Analysis of the association between the pretreatment inclination and the change during treatment of the mandibular incisors showed an inverse relationship. Mandibular incisors, that initially were proclined, tended to become more upright which is in contrast to previous studies indicating that functional appliance treatment generally increases the inclination of these teeth. The results of this study suggest that the correction of the skeletal component of the Class II malocclusion with the Teuscher appliance in most instances takes place by restriction of forward development of the maxilla in combination with downward-forward growth of the mandible, but with wide individual variations. The control of the incisor inclination in the maxilla with this appliance, however, is not adequate and further development in this area is needed. In contrast, the control of the lower incisors by capping helps effectively control these teeth against undesirable proclination during treatment.

The present report deals with the description of craniofacial morphology and growth in an achondroplastic boy followed for a 10-year period. The methods included roentgencephalometry, and metallic implants were inserted in both jaws. Thereby it became possible to differentiate between displacement of the jaws and their bone remodelling. The study showed that in the patient analyzed the primary cause of the worsening of the sagittal jaw relationship was to be found in the growth disturbances of the cranial base rather than in the growth of the jaws per se.

The purpose of the present investigation was to describe the formation, maturation and eruption of the dentition, including supernumerary teeth in a sample of patients with cleidocranial dysplasia. The dentition was evaluated from orthopantomograms, intraoral radiographs, cephalometric films, surgically removed teeth and intraoral photographs in 22 patients (10 men, 12 women), aged 3.5 to 34 years. Formation of primary teeth was normal, whereas all patients but one had supernumerary permanent teeth. Frequency of supernumerary teeth ranged from 22% in the maxillary incisor region to 5% in the molar regions. Anterior to the molar region supernumerary teeth were formed lingually and occlusally to the normal teeth. Maturation of the primary dentition was normal, while permanent teeth were delayed from 1 to 4 years. Supernumerary teeth were delayed about 4 years in relation to normal permanent teeth. Eruption of primary teeth was normal, whereas all patients had severe eruption problems of permanent teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

The development within the field of orthodontics is taking place within both the "hardware" (the brackets and wires) and within the "software" (the concepts behind the design of biomechanics). A survey of the physical characteristics of the new wires is presented. Within the "software" section the differentiation between appliance-guided and orthodontist-guided force systems is important. While the first is a standardized system, the second is goal-oriented and individualized. The advantage in segmented- contra straightwire-technique is discussed in relation to the limitation of orthodontics.

In a 21-year-old man with open bite, myogenic headache and internal derangement of the temporomandibular joint clinical examination was supplemented by radiographs of the joints, cephalometric analysis, electromyographic recordings of the masticatory muscles and tracking of mandibular movements. His condition was characterized by reduced occlusal stability with contact limited to posterior molars, and weak elevator muscles with increased strain during posture and chewing. The purpose of the treatment was to eliminate symptoms with a reflex-releasing stabilizing splint. Secondly, to increase occlusal stability, primarily with the splint and later through orthodontic treatment aiming at closing the bite in the premolar region because the reduced occlusal stability seemed to be a significant etiologic factor. Treatment with the splint reduced signs and symptoms of craniomandibular disorders. During the following orthodontic treatment, contact was established on both premolars and molars, mainly due to extrusion of mandibular premolars. Analysis showed greater elevator strength and decreased muscular loading after treatment. A splint was used for retention accompanied by muscle training with exercise gum. Permanent training with gum was recommended after the retention period.