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Biomedical subjects

B Thilander

Publications and source records attributed to B Thilander.

At least 73 records · Page 4Linked to original sources
PubMed1982

Extraction of third molars in cases of anticipated crowding in the lower jaw.

The purpose of this study was to ascertain whether the lower third molar, in combination with other variables such as facial morphology and space conditions, can contribute to the occurrence or aggravation of crowding. The subjects consisted of twenty-three boys and twenty-nine girls with impacted third molars on both sides of the mandible. The impacted molar on one side was removed, while the other, nonextracted side was used as a control. Average age at the time of operation was 15.5 years (range, 13 to 19). Close to the operation and annually for at least 3 years afterward, study casts and cephalograms (lateral, frontal, and oblique) were taken. The findings indicated that (1) despite analyses of many variables, this study has not been able to predict which patients should react favorably or unfavorably to removal of the third lower molars in cases of anticipated crowding; (2) in cases with severe crowding removal of the molars could be recommended; (3) correct proximal contacts seem to be of importance in keeping the space that is achieved by extraction, while incorrect ones may spoil it.

Adolescent↗
PubMed1982

Roentgencephalometric standards for the facial skeleton and soft tissue profile of Swedish children and young adults. II. Comparisons with earlier Scandinavian normative data.

The purpose of this report is to compare a Swedish so-called normal material (Thilander et al.1983) with previously presented normal materials of Scandinavian origin and with standards for parameters in some frequently used roentgencephalometric systems. The material comprises Swedish children and young adults who fulfil special criteria of normal occlusion and harmonius skeletal relations and in whom roentgencephalometric data were collected. Parts of the material here reported are designated the 10-, 13- and 16-year-old groups. Comparison of the cephalometric data for the age-group 10 years in our material and a previously presented Norwegian normal material (Humerfelt 1970) showed remarkably good agreement for both angular and linear measurements in both sexes. Good agreement was also found between angular measurements in the 16-year-old group and those presented by Werner(1954) for Swedish 13-16-year-old children, but there seem to be differences for certain mandibular parameters. Comparison with data for 12-year-old Swedish boys with varying occlusion, presented by Björk(1947), reveals differences for several angular mandibular measurements. The highly significant differences between the linear measurements in the two materials are probably partly explained by age differences but also tend to corroborate the indications of differences in skeletal pattern suggested by the angular measurements, which are due to the selection criteria. Finally, comparison with the Bergen norms for the straight face (Hasund 1973) shows that the agreement is generally acceptable for angular measurements and the standards may be considered sufficiently reliable for use in clinical orthodontics. They should be supplemental with the age-related variations, however.

Adolescent↗
PubMed1982

Craniofacial morphology and growth in the rat. Cephalometric analysis of the effects of a low calcium and vitamin D-deficient diet.

The influence of a low calcium and vitamin D-deficient diet on the growth and form of the skull of the growing rat was studied using a cephalometric radiographic technique. First, this technique was used to obtain an intra-individual cephalometric description of the normal growth and form of the skull at different ages during postnatal growth in the rat. It was shown that the methodological error and the biological variation between animals were significantly lower than the registered growth changes, thus demonstrating the suitability of the technique. In the animals fed the low calcium and vitamin D-deficient diet and impaired increase in body weight was found. This diet also caused changes in cranial dimensions, both when the deficient animals were compared with control animals of the same age and with control animals with the same weight. It was concluded that the vitamin D-free and low calcium diet caused a disturbed osteogenesis in growth sites determining the growth and form of the viscerocranium and its relation to the neurocranium.

Animals↗
PubMed1980

Gingival tissue reactions to orthodontic closure of extraction sites. Histologic and histochemical studies.

The formation of a hyperplastic gingival tissue with invagination was observed in the extraction areas in seven patients aged 12 to 17 years who, after extraction of the maxillary first premolars, were undergoing orthodontic treatment with an edgewise appliance. This tissue was excised when about 2 mm. of the space remained to be closed. Histologic and histochemical analyses of the biopsy areas demonstrated hyperplasia and increased metabolism in the invaginated epithelium as well as increased production of glucose aminoglycans in the surrounding connective tissue. Loss of collagen was noted in the same regions. There was evidence of bone remodeling rather than only bone resorption in the biopsy area. It was concluded that stimulation from the orthodontic forces was responsible for the hyperplastic tissue reaction and that the increased amounts of glucose aminoglycans may be responsible for possible relapses.

Adolescent↗
PubMed1980

Prevalence of symptoms of functional disturbances of the masticatory system in Swedish men.

Subjective and clinical symptoms of mandibular dysfunction and cuspal interferences were studied in 389 Swedish men (median age 32 years). Impaired chewing function was noted in about 10%, different types of parafunction in 26%, frequent headaches in 5%, TMJ or muscle pain in 3% and difficulties in mouth opening in 10% of the men. Locking or luxation of the mandible was the most prevalent clinical symptom (24%), followed by reduced movement capacity and deviation on opening of the mandible, TMJ-sounds and muscle tenderness. Sixty per cent of the men had one or more clinical symptoms of dysfunction. Subjective symptoms of dysfunction were positively correlated with reduced movement capacity of the mandible and tenderness of the masticatory muscles and temporomandibular joints upon palpation. Positive correlations were found between subjective symptoms of dysfunction and non-working side interference as well as single tooth contact on the working side. Locking or luxation of the mandible and TMJ-sounds were positively correlated with single tooth contact on the working side and TMJ-sounds and muscle tenderness with interferences in the retruded position of the mandible.

Adult↗