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Results for “Periapical Tissue”

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PubMed1990

Histologic reactions to a newly developed calcium phosphate cement implanted in the periapical and periodontal tissues.

A newly developed calcium phosphate cement (CPC), basically composed of tetracalcium phosphate, Ca4(PO4)2O and dicalcium phosphate dihydrate, CaHPO4.2H2O or anhydrous calcium phosphate, CaHPO4, was tested in this study. When combined with water, the cement hardens and produces hydroxylapatite resembling the principal mineral of teeth and bones. Therefore, the CPC should be highly compatible with the body. However, before its clinical application in dentistry, the biocompatibility of CPC in the potential environments of implantation needs confirmation. Eight monkeys were used in our study to test the material in the periapical and marginal periodontal regions. Surgically created periodontal defects were implanted with CPC and hydroxylapatite (HA) (Calcitite 4060). In another application, CPC was pushed into the periapical areas via overfilling of the root canals. Sargenti N2 served as the control material in the periapical test. Generally, only a limited inflammatory response to CPC was found after 6 weeks of implantation in the periodontal area. In the 16-week specimens, the adverse reaction was negligible, and bone regeneration was marked and directly surrounding the CPC. The bone formation activity and biocompatibility in general were found to be even better in the periapical region. The results suggest that the CPC may have a good potential in future clinical applications, although many issues remain to be investigated.

Animals↗
PubMed1992

Comparative immunohistochemical identification and relative distribution of immunocompetent cells in sections of frozen or formalin-fixed tissue from human periapical inflammatory lesions.

The presence of immunocompetent cells (B, Th/i and Ts/c cells and macrophages) and the ratios of these cell populations in periapical lesions (radicular granulomas, radicular cysts and apical scars) were demonstrated immunohistochemically using paraffin and cryo-sections. Thirty-four human periapical lesions were examined for the presence of immunocompetent cells by monoclonal antibodies and the biotin-avidin-horseradish peroxidase method. The T/B cell ratio of radicular cysts was significantly higher than that of both radicular granulomas and apical scars, and the average number of Th/i cells was greater than that of Ts/c cells in the radicular granulomas. However, no significant difference was found between radicular cyst and apical scar. The number of macrophages in radicular granulomas was significantly higher than that of the other lesions. These findings suggested that periapical lesions develop as a result of both humoral and cell-mediated immunological response and indicated that the ratios of immunocompetent cells are different in the different types of periapical lesion.

B-Lymphocytes↗
PubMed1989

[Experimental study on the effect of replantation of immature permanent teeth on the periapical and periodontal tissues].

Replantation and semi-rigid fixation were performed on canine immature permanent teeth, and one week after replantation the teeth were treated by root filling with calcium hydroxide. The root apex and periodontium of the teeth with replantation were examined for changes regularly during the experiment by microradiographic, fluorescence microscopic, polarizing microscopic and X-ray observation of undecalcified horizontal continual ground sections. The results obtained were as follows: 1) Immediately after replantation, root formation was observed, but its formation was found to cease at a relatively early time. No site of the root showed any inflammatory resorption. 2) The dentine of the teeth with replantation was narrow, and the whole tooth substance showed discoloration due to penetration of calcium hydroxide. 3) the periodontal space surrounding the teeth with replantation was decreased daily by new bone actively formed from the alveolar bone proper and by a thin cementum layer added on the periodontal surface. This change occurred from one week after replantation. 4) The width of the periodontal space of the teeth with replantation, which had been wider than that of a control tooth, was increased and decreased daily at the cervix and root apex and the central part of the root, respectively. 5) Collagen fibers of the periodontal membrane were present in the periodontal space of the teeth with replantation, together with regeneration of the periodontal membrane that had been cut by extraction. 6) There were no changes due to replantation in the two teeth adjacent to the tooth with replantation or the lateral jaw.

Cuspid↗
PubMed2002

Matrix metalloproteinase-8 (MMP-8) in pulpal and periapical inflammation and periapical root-canal exudates.

AIM: To study the presence, levels and molecular forms of matrix metalloproteinase (MMP) -8 (collage-nase-2) in pulpal and periapical inflammation, and the changes in MMP-8 levels in root-canal exudates during root-canal treatment. METHODOLOGY: Periapical exudate samples were collected from 11 necrotic teeth with radiographically verified periapical periodontitis during three root-canal treatment visits with interappointment calcium hydroxide (Ca(OH)2) medication. MMP-8 levels and molecular forms were analyzed with immunofluorescent assay (IFMA) and Western immunoblot. Inflamed pulp tissue and periapical granuloma tissue (n = 10 for both) were obtained from other patients and used for MMP-8 immunohistochemical (IHC) staining. RESULTS: The periapical exudate samples demonstrated marked differences in MMP-8 levels between the teeth in the first visit and significant decrease in MMP-8 levels during the root-canal treatment (P = 0.0107). One specimen failed to show a decrease in MMP-8 below 1000 ng mL(-1) a vertical root fracture was later diagnosed and the tooth extracted. IHC staining showed that in addition to PMN-leucocytes, macrophages and plasma cells produced MMP-8 in pulp and periapical granulomas. CONCLUSIONS: The findings demonstrate the presence of MMP-8 in the inflamed pulp and periapical tissue, indicating that MMP-8 has a role in pulpal and periapical inflammation, most likely participating in tissue extracellular matrix degradation. They further indicate that MMP analysis from periapical exudate could be used to indicate and monitor inflammatory activity and the success of treatment in teeth with periapical lesions.

Analysis of Variance↗
PubMed1997

Identification and antibiotic sensitivity of bacteria isolated from periapical lesions.

Periradicular tissues from 28 refractory endodontic cases requiring surgical intervention were submitted for histological diagnosis and microbiological culture. Bacteria isolated from these lesions were identified and then tested for their antibiotic sensitivity to a panel of common antibiotics. The periapical tissue specimens of 22 out of 28 lesions (79%) contained microorganisms. Of the 22 cases showing positive growth cultures, 15 were polymicrobial and 7 were single species isolates. Fifty-three different species were recovered: 29 anaerobes, 19 facultative anaerobes, and 5 aerobes. Microbes were observed under light microscopy in only one case. The most common organisms isolated were Propionibacterium acnes, Staphylococcus epidermidis, Streptococcus intermedius, Wolinella recta, Fusobacterium species, and Clostridium species. Antibiotic susceptibility results showed no clear cut evidence of significant antibiotic resistance among the species tested. The results of this study seem to corroborate earlier studies regarding the microbial population of periapical lesions refractory to nonsurgical endodontics.

Anti-Bacterial Agents↗
PubMed1979

Root canal treatment with calcium hydroxide. I. Effect of overfilling and refilling.

Root canals of dog premolar teeth were negotiated and overfilled with calcium hydroxide paste. After 30 days, half of the treated teeth were refilled up to the apical limit. Root canals not filled were considered as the control group. Ninety days after the first treatment, histologic analysis showed more favorable results in the refilled root canals. The overfilling elicits calcium hydroxide resorption and the ingrowth of periapical connective tissue into the root canal.

Animals↗
PubMed1987

Glass-ionomer cement as retrograde filling material. An experimental investigation in monkeys.

The tissue reaction following the use of glass-ionomer and amalgam, as retrograde filling materials was investigated in an experimental study using 8 monkeys. After apicectomy of the upper central incisors, amalgam and glass-ionomer cement was used at random as retrograde filling material. 2 animals at a time were sacrificed after 2 weeks, 1, 3 and 6 months. Irrespective of the length of time, the tissue reactions were similar for the 2 materials. 2 weeks after surgery, a vascular granulation tissue containing lymphocytes, plasma cells and polymorpho-nucleated leukocytes was observed close to the retrograde fillings. 1 month after surgery, good healing was found, the granulation tissue being replaced by new osteoid or bone formation. After 3 and 6 months, there was complete healing with no inflammatory reaction and a mature alveolar bone surrounding the apicectomized roots.

Animals↗
PubMed1993

Changes in cell proliferative activity in granulation tissue invading the root canal.

Root canal models were implanted in rats in order to investigate histologically the movement of granulation tissue invading apical canals and dead spaces and changes in cell proliferative activity as indicated by 3H-thymidine. The models were prepared to have 1, 2, and 3 mm apical canals, with and without dead spaces, to simulate preparations short of the apex and obturation to several levels. After 12 wks implantation of the models without dead spaces, granulation tissue invading 1 mm apical canals did not degenerate and cell proliferative activity remained high. However, tissue invading the 2 and 3 mm apical canals tended to be necrotic and cell proliferative activity was decreased. In the models with dead spaces, the tissue in the 1 and 2 mm apical canals developed and invaded the dead spaces, and still possessed proliferative activity 12 wks after implantation. In contrast, the tissue in the 3 mm apical canals did not invade the dead spaces, even after 12 wks, and no proliferative activity was observed.

Animals↗
PubMed1979

Detection of immune complexes in human dental periapical lesions by anticomplement immunofluorescence technique.

Twenty-five human dental periapical lesions were obtained. The lesions were frozen, sectioned, and examined for the presence of immune complexes by employing an anticomplement immunofluorescence (ACIF) technique. Twenty-three of the periapical specimens were positive for antigen-antibody complexes. No staining was noted in the two lesions that were histologically diagnosed as periapical scar tissue.

Antigen-Antibody Complex↗