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Biomedical subjects

B Lennartsson

Publications and source records attributed to B Lennartsson.

At least 19 recordsLinked to original sources
PubMed1999

The palatally displaced maxillary canine. A retrospective comparison between an interceptive and a corrective treatment group.

The purpose of this retrospective study was to analyze palatally displaced maxillary canines referred for specialist treatment compared with those successfully treated by the general practitioner by interceptive extraction of either the primary canine or the primary canine and primary first molar. Special interest was focused on chronological age, dental age and dental maturity as well as the position of the canine at the time of recognition and referral. The Interceptive Treatment group consisted of 50 consecutive cases from computerized records, median age 11.7 years (range 8.9-14.11 years). The Corrective Treatment group comprised 47 consecutive cases, median age 14.1 years (range 11.1-18.0 years), referred to the Department of Orthodontics. Information was obtained by assessing the patient charts and radiographs. The results show that age at the time of recognition and referral is the most important factor for the final outcome while the position of the canine concerning angle alpha and sector S is a compromising factor. The results suggest that about one third of the Corrective Treatment group might have had a reasonably good chance of the canine's erupting without corrective treatment if they had been diagnosed and treated with interceptive extraction of the primary canine at an earlier age.

Adolescent↗
PubMed1996

Prevalence of malocclusion and awareness of dental appearance in young adults.

The aims of this study were to determine the remaining subjective and objective need for orthodontic treatment, symptoms of CMD, and headache. 120 boys and 121 girls at 19 years of age participated. They were registered with casts and were sent a questionnaire about chewing ability, headache, subjective symptoms of CMD and experience of orthodontic treatment. They were also asked to give their opinion of their own teeth by putting a mark on a line. The results showed that 89.6% of the adolescents had a normal sagittal molar relationship and 9.6% a postnormal molar relationship. Space conditions of the upper and lower incisors displayed a large range. Most of the adolescents were satisfied with their dentition even though a large range was obvious. Factors of significance for the subjects' subjective opinion of their dentition were space conditions, overjet and inclination of upper incisors. It was concluded that the remaining need of treatment was low, girls being more interested in treatment than boys. The boys' and girls' subjective opinions of their own teeth after treatment were similar. Orthodontic treatment clearly increased the subjects' subjective appreciation of their own teeth.

Adult↗
PubMed1986

Transalveolar transplantation of maxillary canines. An alternative to orthodontic treatment in adult patients.

Transalveolar transplantation of 31 maxillary canines in 26 patients was performed. Fixed orthodontic appliances were used for fixation for 6 to 8 weeks. All the transplanted teeth were firmly affixed in the new positions 3 to 6 months postoperatively. Complete bone regeneration and an attached gingiva with a stippled surface buccally and a normal pocket depth were observed 1 to 2 years postoperatively. These positive treatment results indicate that transalveolar transplantation is a useful alternative in the treatment of impacted maxillary canines in selected patients.

Adolescent↗
PubMed1986

In vitro growth characteristics of human odontogenic keratocysts and dentigerous cysts.

Using an in vitro system, the growth characteristics and enzyme histochemical properties of 3 odontogenic keratocysts and 3 dentigerous cysts were studied. It was found that the epithelial cells of the keratocysts but not of the dentigerous cysts grew in vitro. Furthermore, the epithelial-like cells of the keratocysts showed the same activities of acid phosphatase and NADH-diaphorase in vitro as earlier described in vivo. These enzymatic activities were increased in epithelial-like cells close to proliferating fibroblast-like cells, indicating a close relationship between these two cell types. The results are discussed in the light of the known clinical behaviour of the keratocyst and certain conclusions are also drawn concerning the suggested neoplastic potential of the keratocyst.

Adult↗
PubMed1986

Improvement potential of isolated gingival recession in children.

Eighteen cases showing gingival recession of one mandibular central incisor at a mean age of 9.4 years were recalled 3.9 to 20 years (mean 10.2 years) later. No specific measures had been directed towards the defect except in one case. The gingival status of affected teeth was compared to unaffected adjacent central incisors on an intra-individual basis. No significant difference between groups of affected and control teeth could be shown at the follow-up examination with regard to marginal gingiva level, sulcus depth, bleeding, width of keratinized or attached gingiva, nor in alveolar bone height. Levelling of marginal gingiva in most cases, however, was found to have occurred by a more apical migration of the gingival margin of control teeth. The role of developmental changes in the dentition during growth are discussed, and the importance of recording such parameters in further studies of gingival health in children is underlined.

Adolescent↗
PubMed1984

Effect of post-surgical jaw-orthopaedic treatment in unilateral cleft lip and palate patients.

Reduction of the contraction of maxillary segments in newborn infants with unilateral cleft lip and palate by means of post-operative maxillary orthopaedic treatment was evaluated in 32 consecutive patients. Early surgery was performed in three stages and jaw-orthopaedic treatment with an acrylic plate was started one week after the first and again after the second operation. Between the first and second operation, between the second and third operation and during the period from the first operation to the age of three years there were no significant differences in changes of maxillary width dimensions between half of the children using the plates most frequently and the other half, with one exception. This difference was probably due to differences in initial values between the two groups of children. Thus, the influence on maxillary dimensions and dental occlusion of jaw-orthopaedic treatment, carried out according to our routines, was very limited. On the other hand, other treatment objectives might have been facilitated.

Alveolar Process↗
PubMed1980

Jaw muscle activity during chin-tapping.

Electromyographic (EMG) activity was recorded from the masseter, the anterior temporal and the anterior digastric muscle on the right side of ten dental students when taps were administered upwards or downwards to the chin. The experiment was performed both with relaxed jaw muscles and with contracting depressor muscles. Pairs of intracutaneous platinum hook electrodes were used for the masseter and temporal muscles while concentric needle electrodes were inserted into the anterior digastric muscles. The mean latency of the jaw-jerk elicited in the relaxed masseter muscle when tapping downwards on the chin was 7.8 msec and in the temporal muscle 8.4 msec. The corresponding values of the latency during jaw opening against resistance from the investigator's finger was 8.2 msec and 9.0 msec. During upward tapping on the chin recordings from the anterior digastric muscle showed obvious changes in EMG activity, the latency ranging from 13 to 34 msec. Thus, compared to the latency of the jaw-jerk in the masseter and temporal muscles, which contain numerous muscle spindles, recordings from the anterior digastric muscle, where muscle spindles are thought to be either lacking or few in number, showed no signs of a monosynaptic reflex.

Adult↗
PubMed1980

The occurrence of muscle spindles in the masticatory muscles: a methodological study of different staining techniques.

A method, based on experiment, for more reliable and less time-consuming staining and examination of histological specimens for locating muscle spindles by light microscopy is presented. Sections from the masseter and temporal muscles of the rat were stained with different methods and studied in random order. The method giving the highest number of muscle spindles during scrutiny of the slides (Weigert's iron haematoxylin and van Gieson) is recommended for future studies on the numbers of muscle spindles in a given muscle.

Animals↗
PubMed1980

Number and distribution of muscle spindles in the masticatory muscles of the rat.

The frequency and distribution of muscle spindles in the muscles of mastication of the rat have been studied. The average number of spindles found was 110 in the masseter, 75 in the temporalis and 25 in the medial pterygoid muscle, the spindles being predominantly in the medial parts of these muscles. No muscle spindles were found in the lateral pterygoid or posterior digastric muscle, and only isolated spindles were found in a few of the anterior digastric muscles. These differences between the jaw-closing and the jaw-opening muscles are intriguing and ask for further investigation of the role of the muscle spindles in mastication.

Animals↗
PubMed1979

Muscle spindles in the human anterior digastric muscle.

The occurrence of muscle spindles in the anterior digastric muscle in man was investigated and the fibre calibre spectrum of the corresponding nerve was determined. After removal at autopsy from five individuals of both sexes (aged 23--73), the muscles were stained with Weigert's iron hematoxylin-van Gieson stain and the nerves according to the Alzheimer - Mann - Häggqvist method. Altogether 12 spindles were found in five out of ten muscles. Only muscles from one individual were devoid of spindles. This sparsity or absence was supported by analyses of fibre calibre spectra. The small number of spindles and the fact that they do not occur in all muscles or in all individuals, suggest that they are not an essential source of sensory information.

Adult↗
PubMed1978

Prediction of breadth of permanent canines and premolars in the mixed dentition.

Multiple stepwise regression was used in the selection of mixed dentition variables capable of predicting the total breadth of the unerupted permanent canine and premolars. The material consisted of 77 children. Stone casts were made before and after eruption of the canine and premolars. At the first examination when the children were, on the average, 10 years old, intraoral roentgenograms were obtained of the canine and the premolars. To predict the total breadth of the upper canine and premolars the buccolingual breadth of the upper first permanent molar and measurements on roentgenograms of the breadths of the upper canine and premolars proved most useful. In the prediction of the total breadth of the lower canine and premolars the best results were obtained with measurement of the breadths of the teeth in the roentgenograms. The breadth of the incisors proved less useful as a predictor of the breadths of unerupted canines and premolars.

Bicuspid↗
PubMed1977

Retrograde root filling with amalgam and Cavit.

In a 3-year review of 218 teeth with retrograde root filling with amalgam orCavit, the results obtained with the former proved significantly better than those obtained with the latter. The difference seemed to be due to a better obliteration of the canal by amalgam. The obliterating effect of amalgam probably eliminates the need for revision of incomplete othograde root filling, for example, in cases with a post in the root canal. Irrespective of type of filling materials, the results were less good in cases with marginal bone loss.

Alveolar Process↗