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Biomedical subjects

H Engström

Publications and source records attributed to H Engström.

At least 19 recordsLinked to original sources
PubMed1988

Radiographic evaluation of the effect of initial periodontal therapy on thickness of the maxillary sinus mucosa.

The thickness of the radiographic image of the maxillary sinus mucosa on intraoral radiographs was evaluated in 13 patients with advanced periodontal disease, prior to and 12 months following initial periodontal therapy. Before treatment, a relationship was observed between the thickness of the sinus mucosa and the mean probing depths of the teeth in the involved sextant. As many as 79% of the available sextants showed swelling of the mucosa prior to periodontal therapy, compared to only 17% after treatment. This report supports previous studies indicating that advanced periodontal disease may cause swelling of the maxillary sinus mucosa and that periodontal therapy will significantly reduce such swelling.

Adult↗
PubMed1987

Recovery of maxillary sinus and tooth sensibility after le Fort I osteotomy.

The post-operative effects of maxillary le Fort I osteotomies on tooth sensibility and recovery of maxillary sinus integrity has been studied in thirty patients. The results show that tooth sensibility is lost in over 90% of the teeth post-operatively but gradually returns by 18 months in almost all of the teeth. Radiographic examination of the maxillary sinus post-operatively shows total or almost total radiopacity in all patients whereas later controls at 2 months and 6 months show normalisation of the bony and soft tissue structures in over 55% of the patients. At 6 months some of the patients (30%) show latent mucosal borderline swelling either bilateral or unilateral. A certain remodelling of the maxillary sinus was seen in all patients.

Adult↗
PubMed1987

An ultrastructural and functional study of the inner ear after administration of hyaluronan into the middle ear of the guinea pig.

A single dose of hyaluronan, 19 mg/ml was administered into the right middle ear cavity of guinea pigs. The auditory function of the right ear was tested by recording the gross neural action potential (N1) before, directly after, and 28 days after the administration of hyaluronan. In a control group the right ear was sham-operated and the gross neural action potential (N1) was recorded twice; on the day of the sham operation and 28 days later. All animals were killed 28 days after the operation. All treated as well as sham-operated ears and every second intact ear were studied by scanning electron microscopy (SEM.) No ear had signs of hearing deterioration. Macroscopically, most of the hyaluronan was eliminated from the middle ear after 28 days. In the histological examination, pathological stereocilia were found in the apical turn of the cochlea in the ears to which hyaluronan was administered, the sham operated and the intact ears.

Animals↗
PubMed1987

Effects of irradiation on growing bones.

The effects of irradiation on various tissues have been studied extensively. Nonetheless, the metabolism in growing bones has not been evaluated in a systematic way after moderate doses of irradiation. It was found that scattered radiation, that reaches the oral region during radiotherapy of malignancies outside the oral region, causes absorbed doses within the range of 0.2-20 Gy, while absorbed doses from radiography in orthodontics were only 30-40 mGy. Bone formation in the metaphyseal area of rat tibia in vivo after irradiation with 0.5-8 Gy was determined by a tetracycline labelling method. Five and 8 Gy induced a significant growth retardation. This was detectable already after 36 hours and was maximal 7-14 days after irradiation. Between 14 and 30 days following irradiation growth was normalized. Alkaline phosphatase (ALP) activity in bone was evaluated biochemically and decreased one day after irradiation with 0.5-8 Gy. This was followed by a gradual increase in ALP activity and a return to normal values 30 days after irradiation. Histochemical studies of the rat tibias included evaluation of ALP, acid phosphatase, NADH2-diaphorase and Glucose-6 phosphate dehydrogenase. A decrease in ALP activity one day after irradiation was observed with 5, 8, and 10 Gy. Acid phosphatase and the two oxidative enzymes were increased in activity during the entire 7-day experimental period, reflecting an altered metabolism. Normal activities of all the studied enzymes were observed 30 days after irradiation. Results from suture area and synchondrosis area as evaluated by histochemistry and a cephalometric radiographic method showed that early transient metabolic changes occurred in the craniofacial growth sites after irradiation with 5 and 8 Gy. The morphological changes observed in anatomical regions within the irradiated field (neurocranium) persisted in contrast to the changes in the viscerocranium that were normalized at the end of the experimental period. An in vitro system was used to examine the effects of irradiation on certain aspects of bone growth. Mice calvaria were irradiated in vitro with 2 or 10 Gy. A different response in suture and bone was found 3 hours to 4 days after irradiation. Bone was affected by 2 Gy, but not the suture. Thus, the suture seems to be an area with more radioresistant fibroblast-like cells than the cortical bone, which indicates a difference in radiosensitivity of the cells in these two growth sites. The conclusions from the present thesis are that irradiation with 2-10 Gy of bone both in organ culture and in experimental animals induces metabolic and morphologic changes which were detected early and were transient.

Animals↗
PubMed1986

Metaplastic formation of bone and chondroid in flabby ridges.

The present study was undertaken to demonstrate certain histological characteristics of biopsies from flabby ridges. Our results show that metaplastic formation of bone and chondroid are found in specimens from patients where radiopaque structures were visible on radiographs outside the alveolar ridge. Another aim was to demonstrate the metabolic activity of these zones especially as formerly they were believed to be non-vital. The cells in the vicinity of the bone and cartilage showed a higher activity of all metabolic enzymes studied than did ordinary fibroblasts; also the osteocytes and chondrocytes showed positive reactions for several enzymes.

Alveolar Process↗
PubMed1983

Lower third molar development in relation to skeletal maturity and chronological age.

The development of lower third molar anlage was investigated longitudinally and related to chronological age and to skeletal maturation stage as judged by the mineralization of epiphyses in the hand. Strong correlations were found between lower third molar development and both skeletal maturation and chronological age. These results indicate that lower third molar development on the whole seems to be correlated with skeletal maturation. One or two lower third molars were found to be missing in 11% of the subjects.

Adolescent↗
PubMed1983

Effect of 50 kV irradiation on enzyme activities of growing rat bone. A histopathologic and enzyme histochemical investigation.

Young rats were exposed to 2, 5, 8 and 10 Gy 50 kV local irradiation. The epiphyseal region of the proximal tibia was examined with histopathologic, histochemical and enzyme histochemical methods 1 to 90 days after irradiation. One day after irradiation, a decrease in alkaline phosphatase activity was noted and increased activity was found for acid phosphatase, NADH2-diaphorase and glucose-6-phosphate dehydrogenase, especially after 8 and 10 Gy, but also after 5 Gy. Three days after irradiation, all enzymes showed an increased activity and on day 7 the findings resembled those on day 3. Thirty days after irradiation, a return to normal conditions was observed. The most marked morphologic changes were swelling of cells in the hypertrophic cell zone, disturbed order of cells in the zone of proliferation and an increased number of osteoclasts in the metaphyseal bone. These alterations appeared 1 to 3 days after irradiation and normal morphology was seen on day 30 after 2, 5 and 8 Gy and 90 days after irradiation with 10 Gy.

Acid Phosphatase↗
PubMed1983

Effect of local irradiation on longitudinal bone growth in the rat. A tetracycline labelling investigation.

Young rats were given a single local irradiation dose (0.5, 2, 5 or 8 Gy) to the left knee-joint. The right unexposed knee-joint served as control. The animals were decapitated 1.5, 3, 7, 14 or 30 days after the irradiation. Longitudinal bone growth in the tibial epiphysis was established using tetracycline as an intravital marker. During the first 1.5 days after irradiation with 5 and 8 Gy, the growth was slightly inhibited (6-7%). Maximum growth retardation (20%) was found 7 to 14 days after irradiation with 5 and 8 Gy. No consistent effect occurred after 0.5 and 2 Gy. Between 14 to 30 days following irradiation growth was normalized.

Animals↗
PubMed1980

Radio-diagnostic difficulties with mandibular lesions.

Periapical radiolucencies are by far the most common pathological processes shown in dental radiographs. The difficulties of interpreting the appearances are discussed on the basis of three cases with diagnostic difficulties. The demand for a close relationship between medical and dental disciplines is emphasised, as the oral cavity is often an indicator of general disorders of the body.

Adolescent↗
PubMed1980

The anatomy of the lower-third-molar roots and its relation to the mandibular canal.

The root anatomy of the lower third molars and the distance from apex to the mandibular canal were examined in radiographs. Three different materials were examined; one medieval with erupted teeth, one modern with erupted teeth and one modern with impacted third molars. Uncomplicated root anatomy was recorded for 75% of the teeth in the medieval material and for 20% in the modern materials. A position of the root apex near the mandibular canal was more frequently observed in the modern material.

Female↗
PubMed1979

The labyrinth of the American bullfrog.

The labyrinth of the American bullfrog (Rana catesbiana) has been studied by aid of light and electron microscopy. Cell counts and sensory area mapping has been made and it has been shown that scanning electron microscopy is the most appropriate technique at present for cell counts.

Animals↗
PubMed1978

Structure of the hairs on cochlear sensory cells.

A study of cochlear sensory hairs has been made using transmission and scanning electron microscopy. The structure of the hairs and the relation to the hair cells and to the tectorial membrane is described. A number of micrographs demonstrate both the inner structure of the hairs and their relation to the surrounding structures.

Animals↗