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Biomedical subjects

G Bergenholtz

Publications and source records attributed to G Bergenholtz.

10 recordsLinked to original sources
PubMed1992

Accessory cells in the immune defense of the dental pulp.

This communication focuses on the participation of accessory cells in the initial recognition and processing of antigenic substances in the dental pulp. Immunohistochemical analyses have demonstrated the presence of two types of accessory cells--one with a dendritic morphology located in the periphery of the pulp and one with a macrophage-like appearance located more centrally. Functional studies in vitro have provided evidence for the dendritic cells being the most significant of the two cells regarding their capacity to induce T-cell proliferation. Studies on ontogeny have revealed that the appearance of pulp accessory cells is delayed compared to other peripheral tissues. In experimentally induced pulp lesions a rapid increase of cells with morphologic and phenotypic features similar to normally occurring accessory cells was found. These data demonstrate that the dental pulp contains the necessary cellular constituents to mount an immunologic defense reaction. Future studies should focus on elucidating possible interactions between these immune cells and the neurovascular system of the pulp.

Antigen-Presenting Cells↗
PubMed1991

Ontogeny of class II antigen expressing cells in rat incisor pulp.

Class II antigen expressing cells are generally associated with the early phase of the immune response. Dendritic cells and macrophages expressing these cell surface antigens have recently been demonstrated and characterized in the dental pulp. The present study was undertaken to determine when the pulp receives its immunologic defense potential by examining the temporal appearance of class II antigen expressing cells in the rat incisor pulp. Pulp tissue specimens obtained at various time periods from a gestational age of 16 days to 14 wk after birth were examined by immunohistochemistry using O x 6 as a primary antibody and the ABC-technique. Comparisons were made with tissue samples from the spleen, intestine, skin and oral mucosa. At birth, all tissues, except for the pulp, presented cells expressing class II antigen with a dendritic appearance in a number and orientation resembling the mature tissue. A complete distribution of these cells was not seen in the dental pulp until 7 weeks following birth. Data show that the dental pulp acquires its ultimate structural arrangement of immune cells later than other tissues.

Animals↗
PubMed1979

Retreatment of endodontic fillings.

Effects of endodontic retreatment on quality of seal and periapical healing were assessed among 660 previously root-filled roots. The roots were divided into either of two groups according to presence or absence of pathologic alterations in the periapical area. The retreatments, which were carried out by dental students, involved a thorough chemomechanical debridement of the root-canal system aiming to control infection. Following a 2-year observation period 556 roots were reexamined clinically and radiographically. The results showed that root-fillings with technical shortcomings could, following retreatment, be markedly improved as regards effectiveness of seal and distance to the apex. A large number of lumina discernible apical to root-filling could also be treated and filled. Seventy-eight percent of the cases with pathologic lesion present periapically prior to retreatment either completely healed or displayed an obvious size-reduction of the process. Retreatments carried out because of technical inadequacies alone were successful in 94% of the cases. It was concluded that renewed endodontic treatment whenever possible is the method of choice when treating defective endodontic fillings complicated with pathologic processes periapically. Apical surgery may be attempted if no signs of healing are apparent following observation.

Adult↗
PubMed1978

Effect of experimentally induced marginal periodontitis and periodontal scaling on the dental pulp.

Experimental breakdown of the periodontal attachment apparatus was produced in six young adult monkeys to study the effect on the tissue of the dental pulp by (1) periodontitis, (2) scaling and plaque accumulation on exposed root dentin. Periodontal tissue breakdown was induced by the placement of ligatures around the neck of 92 permanent teeth. Subsequent plaque formation caused marked loss of periodontal tissue support, which after a period of 5--7 months amounted to 30--40% of the root length. One group of teeth received no further treatment. Other teeth were subjected to scaling and root planing. Following treatment, plaque was allowed to accumulate for 2, 10, and 30 days on the freshly planed root dentin surfaces. Histologic examination revealed that in comparison to teeth with normal periodontal conditions, 57% of the teeth exposed to periodontitis exhibited pathologic pulp tissue alterations. Secondary dentin formation and/or inflammatory cell infiltrates were observed within localized areas of the pulp subjacent to root surfaces exposed to periodontal tissue destruction. The changes within the pulp were of "mild" nature and only one tooth displayed signs of total pulp necrosis. Lateral canals communicating with both the pulp cavity and the exposed root surface were never detected. Teeth subjected to scaling and subsequent plaque accumulation in comparison with teeth with periodontitis alone exhibited no obvious aggravation or increased incidence of pathologic pulp reactions. The findings show that in the monkey (1) periodontal destruction limited to the cervical half of the root and (2) plaque accumulation on exposed root dentin does not cause severe alteration in the pulp of the roots involved.

Animals↗
PubMed1977

Experimental pulpitis in immunized monkeys.

Bovine serum albumin (BSA) was topically applied to exposed dentin to assess whether inflammatory reactions can be induced in the pulp of monkeys immunized against BSA. Four cynomolgus monkeys received repeated injections of BSA emulsified with Freund's incomplete adjuvant. Pulp challenge was performed by applying BSA in freshly cut dentin cavities prepared on the buccal surface in 34 teeth. In 29 control teeth ovalbumin (OVA) was applied. Control applications of BSA were also performed in 15 teeth prepared in three nonimmunized monkeys. Forty-eight hours after the initiation of the pulp challenge the monkeys were sacrificed and the pulp tissue examined in the light microscope. Topical application of BSA to freshly exosed dentin in immunized monkeys resulted in severe inflammatory lesions in the pulp, characterized by bleeding and extravascular infiltration of large numbers of leukocytes. Extensive tissue damage was an important feature in several pulps. Identical applications of OVA in control teeth and BSA applications in nonimmunized monkeys produced no such reactions. The results indicate that interactions between antigens and antibodies can occur within the dentin-pulp area and following the formation of immune-complexes, severe injury to the pulp can be induced.

Administration, Topical↗
PubMed1975

Effect of soluble plaque factors on inflammatory reactions in the dental pulp.

The present investigation was undertaken to determine whether soluble factors from human dental plaque are capable of inducing or mediating pathological alterations in the dental pulp. The experiment was performed in three monkeys and involved 40 teeth in all: 20 test and 20 control teeth. Class V cavities were prepared on the buccal surface close to the marginal gingiva. In the test cavities an extract of human dental plaque was applied once very 5 min during an 8-h period. The cavities of the contralateral teeth were treated in an identical manner but with Ringer's solution. The animals were sacrificed 10 or 32 h after the initiation of the test. Two hours prior to sacrifice the animals were injected with colloidal carbon and then perfused with 10% neutral buffered formalin. Histologic examination demonstrates that the pulp tissue response to topical application of a plaque extract was characterized by (1) increased degree of carbon retention - indicative of vascular exudation and (2) enhanced rate of emigration of neutrophils and monocytes.

Animals↗
PubMedDate not supplied

Evaluation of the desensitizing effect of Gluma Dentin Bond on teeth prepared for complete-coverage restorations.

This clinical trial assessed the ability of Gluma Dentin Bond to inhibit dentinal sensitivity in teeth prepared to receive complete cast restorations. Twenty patients provided 76 teeth for the study. Following tooth preparation, dentinal surfaces were coated with either sterile water (control) or two 30-second applications of Gluma Dentin Bond (test) on either intact or removed smear layers. Patients were recalled after 14 days for a test of sensitivity of the prepared dentin to compressed air, osmotic stimulus (saturated CaCl2 solution), and tactile stimulation via a scratch test under controlled loads. A significantly lower number of teeth responded to the test stimuli for both Gluma groups when compared to the controls (P less than .01). No difference was noted between teeth with smear layers intact or removed prior to treatment with Gluma.

Chi-Square Distribution↗
PubMedDate not supplied

Effect of bacterial products on inflammatory reactions in the dental pulp.

Culture filtrates (extracellular components) and material obtained from disintegrated cells (intracellular components) of cultured plaque bacteria were studied for their capacity to induce inflammatory reactions in the dental pulp. Class V cavities were prepared on the buccal surface of 94 teeth: 42 test and 52 control teeth in six adult monkeys. lyophilized bacterial components were sealed into the test cavities either alone or following an 8-h topical application of a solution of the same components in phosphate-buffered saline (PBS). Culture medium and PBS were applied in two sets of control cavities. A third set was restored with zinc oxide-eugenol cement. The animals were killed 32 h after the initiation of the experiment and the pulps were examined histologically. Teeth treated trophil leukocytes in the area of the pulp subjacent to the cut dentin tubules. Abscess formation was frequently found. The severe reactions which developed were independent of differences between individual animals and differences in thickness of the remaining dentin. The controls showed damage to the odontoblasts but little or no neutrophil infiltration. The findings confirm that products of bacteria applied to exposed dentin initiate inflammatory reactions in the dental pulp.

Animals↗