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Biomedical subjects

J J Ravn

Publications and source records attributed to J J Ravn.

At least 37 records · Page 2Linked to original sources
PubMed1976

Developmental disturbances in permanent teeth after intrusion of their primary predecessors.

The frequency and type of developmental disturbances in the permanent teeth in relation to the child's age at the time of injury were examined in 78 patients with 100 intruded primary incisors. The central incisors were found to be the most frequently affected teeth. Only maxillary teeth were involved. The dominating age group was 1-3 years and intrusion was seldom seen after the age of 4 years. The frequency of disturbed normal development of the permanent teeth was 54%. In eight cases the intruded teeth were removed immediately, 86 teeth reerupted, and six teeth did not reerupt. Internal white enamel hypoplasia was seen frequently; external hypoplasia, seldom.

Age Factors↗
PubMed1976

Sucking habits and occlusion in 3-year-old children.

The material for the present study comprises plaster models of 310 Copenhagen children, impressions for which were taken during the month each child attained the age of 3 years. The occlusion was related to information concerning the child's sucking habits up to the time of the study. The effect of sucking habits of sagittal occlusion was observed in the canine region and the molar region. A higher proportion of distal canine relationships was recorded in children who continued to suck dummies at the age of 3 years than among finger-suckers of children who have never sucked. In primary second molar region no significant difference was recorded between the various sucking groups. The open bite is clearly dominant among children who persist with a sucking habit.

Child, Preschool↗
PubMed1975

Occlusion in the primary dentition in 3-year-old children.

The material for the present study comprises plaster models of 310 Copenhagen children, impressions for which were taken during the month each child attained the age of 3 years. On the basis of fixed criteria a description is given of individual symptoms of occlusion. Using the primary canines as the guide to occlusion it was found that the same occlusion at both sides occurs in 79.7% of the overall total, the remaining 20.3% having different occlusion at each side. Approximately one-half recorded neutral occlusion at both sides, and one-third had distal occlusion at both sides. The termination pattern of the dental arches in centric occlusion were normal or straight in 68.0% and bilateral distal in 14.8%. In 82 subjects or 27% of the degree of overlapping was greater than or equal to half the height of the mandibular central incisors. The number of cross-bites constituted 11.6% of all subjects. Assessment of spacing was undertaken exclusively on the basis of whether or not a space existed. About 3.5% of all subjects had close contact between all teeth in the maxilla or crowding, and about 24% had spacing between all teeth in the maxilla. In the mandible about 5% had close contact between the teeth and only 15% had spacing between all teeth in the mandible.

Child, Preschool↗
PubMed1975

Developmental disturbances in permanent teeth after exarticulation of their primary predecessors.

The frequency and type of developmental disturbances in the permanent teeth in relation to the patient's age at the time of injury were examined in 77 patients with 85 exarticulated primary incisors. The central incisors are the most frequently affected teeth and injuries occur more often to teeth on the right than on the left side. The frequency of disturbed normal development of the permanent teeth was 74.1% for the total material. From 0-2 years the frequency is 94.5% and after the age of 5 years the frequency is only 18.2%. External enamel hypoplasia is the more common result in patients whose trauma occurred when they were less than 3 years old, whereas internal enamel hypoplasia is the unsual result of traumas occurring after the age of 3 years.

Child↗