The aim of the study was to assess the prevalence of malocclusion in a population of Bogotanian children and adolescents in terms of different degrees of severity in relation to sex and specific stages of dental development, in order to evaluate the need for orthodontic treatment in this part of Colombia. A sample of 4724 children (5-17 years of age) was randomly selected from a population that attended the Dental Health Service; none had been orthodontically treated. Based on their dental stages the subjects were grouped into deciduous, early mixed, late mixed and permanent dentition. The registrations were performed according to a method by Björk et al. (1964). The need for orthodontic treatment was evaluated according to an index used by the Swedish National Board of Health. The results showed that 88 per cent of the subjects had some type of anomaly, from mild to severe, half of them recorded as occlusal anomalies, one-third as space discrepancies, and one-fifth as dental anomalies. No clear sex differences were noted, except for maxillary overjet, spacing, tooth size (all more frequent in boys), and crowding (more frequent in girls). Occlusal anomalies and space discrepancies varied in the different dental developmental periods, as did tipped and rotated teeth. Little need for orthodontic treatment was found in 35 per cent and moderate need in 30 per cent. A great need was estimated in 20 per cent, comprising children with prenormal occlusion, maxillary overjet, or overbite (> 6 mm), posterior unilateral crossbite with midline deviation (> 2 mm), severe crowding or spacing, congenitally missing maxillary incisors, impacted maxillary canines or anterior open bite (> 3 mm in the permanent dentition). Urgent need for treatment was estimated to be 3 per cent, comprising subjects with extreme post- and pre-normal occlusion, impacted maxillary incisors or extensive aplasia.

No abstract

– The prevalence of malocclusion was studied in 6,398 Swedish schoolchildren They were divided into two groups. Group 1 consisted of 2,664 boys and 2,795 girls in the town of Umeå. The children were examined at 7, 10 and 13 years of age. Group 2 was made up of 429 boys and 510 girls referred from the district of Västerbotten and examined only once. Dental anomalies of the permanent teeth, and space and occlusal anomalies were recorded. Of the children in Group 1 73.8% had some form of anomaly. Of these, 52.3% were occlusal anomalies, 32.6% space anomalies and 14.9% dental anomalies. Of the referred children (Group 2) 44.8% had occlusal anomalies, while space and dental anomalies were equally common (29.4% and 25.8%, respectively).

The purpose of the experiment reported was to study soft tissue changes at teeth which were orthodontically moved into areas with varying thickness and quality of periodontal tissues. The maxillary central incisors and first premolars in 5 adult monkeys were used as experimental teeth. 6 months prior to the start of the orthodontic treatment phase, the maxillary second premolars were extracted. By surgical means, areas with varying width of the keratinized gingiva were established in the incisor and premolar region. Following a clinical baseline examination which involved assessments of gingival width, location of the gingival margin in relation to cemento-enamel junction and probing attachment level, fixed orthodontic appliances were inserted in order to bodily move the two contral incisors in labial direction through the alveolar bone envelope and the first premolars in distal direction into contact with the first molars. Orthodontic forces were applied for a period of 3-4 months. The lateral incisors and first molars were selected as non-moved control teeth. After the experimental teeth had been retained in their new positions for 1 month, the clinical examination was repeated. Tissue blocks containing test and control specimens were subsequently dissected and prepared for microscopic analysis. The analysis included histometric assessments of loss of connective tissue attachment and height of alveolar bone. The results showed that at every second labially moved incisor, the gingival margin had become displaced in apical direction. The degree of displacement, however, was small and only at 2 teeth accompanied by loss of connective tissue attachment. Throughout the study, these particular teeth also showed obvious signs of gingival inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)