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Biomedical subjects

I Ericsson

Publications and source records attributed to I Ericsson.

At least 55 records · Page 3Linked to original sources
PubMed1990

Some anatomical features of the periodontium of the deciduous and permanent dentition in the beagle dog.

The present study describes some anatomical characteristics of teeth and periodontal tissues in the deciduous and permanent dentition of the beagle dog. Five animals were used. At the age of 10 weeks (Period A) and 15 months (Period B), respectively, a plaque control period was initiated. At the end of each plaque control period, clinical examinations were performed. Biopsies were obtained from the 02P, 03P (Period A) and P3, P4 (Period B) tooth regions and were examined with the light microscope. Histometric and morphometric measurements were made. The macroscopic and microscopic measurements revealed that marked differences exist between the teeth and the periodontium of the deciduous and the permanent dentition. The permanent premolar erupting into the position of the deciduous premolar was found to be significantly wider and higher than its precursor. Also the shape of the crown of the permanent premolar differed from that of the deciduous premolar. The sinuous contour of the buccal gingival margin was more accentuated in the deciduous than in the permanent dentition. The free gingiva was shorter and the periodontal ligament space was wider in the deciduous than in the permanent dentition. The free gingival unit in the deciduous dentition consisted of a larger volume of epithelium and a smaller volume of connective tissue than the corresponding unit in the permanent dentition. The connective tissue of the deciduous gingiva contained a larger proportion of fibroblasts and a lower proportion of collagen fibres than the corresponding tissue of the permanent gingiva.

Animals↗
PubMed1990

Histology of tissues surrounding single crystal sapphire endosseous dental implants: an experimental study in the beagle dog.

9 single crystal sapphire dental implants were installed bilaterally into pre-extracted areas in the lower jaw of two beagle dogs and histologically analysed after 180 days in situ. 8 implants were stable and radiographs disclosed complete bone healing. Light-, scanning- and transmission electron microscopy demonstrated that the stable implants were surrounded by a mineralizing bone boundary and a mucosa nearly free from inflammatory cell infiltrations. The 9th implant was mobile and surrounded by a non-mineralized connective tissue capsule containing bundles of collagen. The ultrastructure of the mucosa surrounding the implants closely resembled the mucosa surrounding the tooth. Histometric analysis of the alveolar bone surrounding the stable implants revealed that the value of the bone contact surface ranged from 37.1% to 86.9% (mean value 61.8%) at the light microscopic level.

Alveolar Process↗
PubMed1990

Histometric and ultrastructural studies of tissues surrounding Astra dental implants in dogs.

Twenty-four Astra titanium dental implants were inserted bilaterally, three on each side, into the mandibles of four dogs to study mucosal and bone-implant junctions. After a healing period of 6 months, the dogs were sacrificed and bone sections with implants were removed and processed for histologic evaluation. All implants were stable, and radiographs disclosed complete bone healing. The surrounding mucosa closely resembled that surrounding natural teeth. Histometric analysis of the alveolar bone revealed that, on average, 61.3% of the implant surface interface was integrated in the bone at the light-microscopic level.

Alveolar Process↗
PubMed1989

[Titanium implants of Brånemark type for oral rehabilitation of partially edentulous patients].

This paper describes the principles for different types of partial reconstructions using tissue integrated titanium fixtures, according to the Brånemark technique, as abutments for fixed bridges. The implant-supported bridges can be designed either in separate units (Type I) or integrated into tooth-supported reconstructions (Type IIA and Type IIB). The different designs of the fixed bridge-work are illustrated by a number of patient presentations.

Adult↗
PubMed1989

Gingivitis in the deciduous and permanent dentition. An experimental study in the dog.

The present investigation was performed in order to study the reaction of the gingiva in the deciduous and permanent dentition of dogs to 3 weeks of plaque accumulation. The study was carried out in 10 beagles, divided into 2 groups of 5 dogs each; group I and group II. When the dogs of group I were 10 weeks old, a meticulous plaque control regimen was initiated in order to establish clinically healthy gingiva. After 6 weeks of plaque control, the gingivae of the lower deciduous molars was exposed to a clinical examination, and biopsies as well as bacterial plaque samples were harvested from tooth 03P and 02P. A second plaque control regimen was initiated when the same dogs were 15 months old. After 6 weeks of plaque control, the gingiva of the permanent dentition was examined and biopsies sampled from tooth P3 and P4. In the dogs of group II, plaque control regimens of 3 weeks duration were initiated when the animals were 10 weeks and 15 months old. Clinical examinations were performed at the end of each 3-week period. Immediately after the clinical examinations. 3-week periods of plaque accumulation were initiated. Examinations and plaque sampling were performed after each of these 3-week periods and biopsies were sampled from the deciduous and permanent dentition as described for group I. The biopsies were processed for histometric and morphometric measurements. The findings from the experiment showed that careful plaque control resulted in the establishment of clinically healthy gingiva. In both the deciduous and permanent dentition, however, a clinically healthy gingiva was found to contain a small inflammatory cell infiltrate (ICT). 3 weeks of plaque accumulation resulted in both dentitions in the development of clinical signs of gingivitis and in the formation of comparatively large ICT. The large ICT of the permanent gingiva resided in the coronal portion of the free gingival unit, while in the deciduous dentition, the inflammatory lesion occupied a narrow tissue portion along the entire border of the dento-gingival epithelium. The ICT of the permanent gingiva harbored a larger portion of plasma cells than the inflammatory lesion studied in the deciduous dentition.

Animals↗
PubMed1988

Structural beta-cell changes and transient hyperglycemia in mice treated with compounds inducing inhibited citric acid cycle enzyme activity.

An initial transient hyperglycemia was seen in mice injected with asparagine, fluoroacetate, hydroxylamine, or malonate plus methionine, whereas an initial triphasic blood glucose response and a transient "secondary" hyperglycemia were exhibited in those injected with hydroxylamine plus arsenite, and a delayed hypoglycemia was observed in those treated with fluoroacetate or arsenite. The glucose-induced insulin secretion was significantly decreased in isolated pancreatic islets incubated with hydroxylamine plus arsenite. Light and electron microscopy, pyroantimonate technique, and X-ray microanalysis disclosed mitochondrial damage, degeneration, and necrosis among the beta-cells in the islets of mice injected with hydroxylamine plus arsenite. Glycogen depletion and microvesicular fatty change were seen in the liver of mice treated with fluoroacetate, arsenite, or hydroxylamine plus arsenite. These observations support the view that inhibition of the activity of citric acid cycle enzymes and associated reactions in the beta-cells play a role in the induction of diabetic features.

Animals↗
PubMed1987

Lack of bacterial invasion in experimental periodontitis.

The present study in the beagle dog was performed to analyze whether micro-organisms from a subgingival microbiota could be translocated into or had the potential to invade the pocket epithelium and the gingival connective tissue during a phase of rapid breakdown of the attachment apparatus. An attempt was also made to assess whether tetracycline therapy suppressed the subgingival microbiota and changed the size and quality of the lesions in the gingival tissue. 5 inbred beagle dogs were used. Throughout the period of experimentation, the animals were fed a soft diet permitting gross accumulation of plaque and calculus. No mechanical plaque control measures were performed during the course of the study. On day 0, a 120-day period of periodontal tissue breakdown was initiated at the right mandibular 3rd and 4th premolars by tying cotton floss ligatures around the neck of these teeth. The process of tissue breakdown at the mandibular left 3rd and 4th premolars was started 30 days later. The ligatures were replaced once every 2 weeks during the subsequent 4-month period. On experimental day 120, the first biopsy was performed and gingival tissue sections prepared for light and electron microscopic assessment of a series of histometric characteristics. On day 120, a 30-day period of tetracycline (per os) administration was initiated. Each dog was given a dose of 500 mg tetracycline twice daily. On day 150, the biopsy procedure was repeated in the mandibular left premolar regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

A histologic comparative study of the midpalatal suture and periodontal ligament tissue in the beagle dog.

The present investigation describes the morphological difference between the suture and the periodontal ligament in beagle dogs. Specimens from five beagle dogs, 2 yr old, containing the anterior portion of the maxilla were used. Following routine histologic preparations frontal sections were cut with the microtome. The sections were stained and studied in the light microscope. The fibers in the midpalatal suture seemed coarser and less organized than the fibers in the periodontal ligament tissue. The vessels in the suture had thicker walls than the vessels in the periodontal ligament. A probable reason for the morphological differences between the two tissues is discussed.

Animals↗
PubMed1986

Inhibition by streptozotocin of the activity of succinyl-CoA synthetase in vitro and in vivo.

The activity of succinyl-CoA synthetase from mouse liver and kidney was inhibited by streptozotocin in vitro. Streptozotocin behaved essentially as a non-competitive inhibitor, and the following kinetic values were obtained (in the presence of 10 nM streptozotocin): apparent Km 1.7 mM, apparent Ki 10 nM, and kcat 440 nkat X kg-1. Compared with non-diabetic control mice, the succinyl-CoA synthetase activity was significantly decreased in the islets and kidneys of mice with early (1 h) and manifest (greater than or equal to 2 days) streptozotocin diabetes, whereas the activity in the liver was not significantly altered. Inhibited succinyl-CoA synthetase activity is believed to play a prominent role in the cellular effects of streptozotocin.

Animals↗
PubMed1986

The condition of the soft tissues at tooth and fixture abutments supporting fixed bridges. A microbiological and histological study.

In 10 partially edentulous patients provided with fixed bridgework supported by the combination of tooth and titanium fixture abutments, the condition of the soft tissues surrounding the abutments was examined. Sampling of supra- and subgingival plaque was performed from both teeth and fixtures. The samples were analyzed regarding the total bacterial counts, the relative distribution of bacterial morphotypes and the cultivable microflora. From each patient, soft tissue biopsies were obtained from 1 tooth and 1 fixture abutment, and the specimens were analyzed for the presence and extension of inflammatory cell infiltrates. The microbiological examination showed that the distribution of bacterial morphotypes in the supra- and subgingival plaque both at teeth and fixtures were similar, irrespective of localization and type of abutment. Nonmotile rods dominated the microflora, whereas spirochetes were either not detected or occurred in very low proportions. From the histological analysis, it was found that a majority of the soft tissue biopsies (75-80%) from both tooth and fixture sites contained only very small inflammatory cell infiltrates.

Adult↗
PubMed1986

The combined effects of plaque and physical stress on periodontal tissues.

Experiments have been performed in beagle dogs in attempts to evaluate the effect of orthodontic- and jiggling-type trauma on the supporting structures of premolars. The results reported have unanimously demonstrated that in situations where orthodontic or jiggling forces were inflicted on teeth with a normal periodontium, or on teeth with overt signs of gingivitis, the periodontal ligament tissue reacted by transitory signs of inflammation. These phenomena occurred without a concomitant loss of connective tissue attachment and development of pathologically deepened periodontal pockets. If the jiggling trauma was inflicted on teeth with an ongoing plaque-associated, destructive periodontitis, the resulting inflammatory reactions caused enhanced loss of attachment and angular bony defects. Furthermore, orthodontic tilting movements of teeth (intrusion) in a plaque-infected dentition may shift a supragingivally located plaque into a subgingival position resulting in periodontal tissue breakdown.

Animals↗
PubMed1986

A clinical evaluation of fixed-bridge restorations supported by the combination of teeth and osseointegrated titanium implants.

The present paper reports on the result of the use of osseointegrated titanium fixtures and teeth as combined abutments for fixed-bridge restorations in 10 partially dentate patients. In these patients, the remaining teeth were too few or too unfavourably distributed in the jaws to serve as sole abutments for fixed bridgework. Titanium fixtures ad modum Brånemark were therefore implanted in suitable positions and used as abutments in combination with the remaining teeth. Evaluations at periods of 6 to 30 months postoperatively revealed good clinical results. Some tissue reactions, however, were also observed, indicating the presence of certain clinically significant differences in the functional behaviour of tooth abutments and titanium fixture abutments. These reactions and differences are discussed.

Adult↗