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PubMed2006

Structure of the periodontium in cathepsin C-deficient mice.

Papillon-Lefevre syndrome is characterized by increased susceptibility to early-onset periodontitis and is caused by mutations in the cathepsin C gene. How deficiency of the enzyme relates to an increased periodontal infection risk is still not entirely clear. One possibility is that the deficiency leads to changes in the structure of the periodontal tissues as a result of which its barrier function to pathogens is compromised. We studied the structure of the periodontium in 9-month-old cathepsin C-deficient mice (cathepsin C(-/-)) and compared this with age-matched wild-type mice. Our observations showed that the overall structure of the gingiva, periodontal ligament, alveolar process, and cementum layer are normal in cathepsin C(-/-) mice, with one exception, namely that epithelial rests of Malassez in the periodontal ligament of the cathepsin C(-/-) mice are slightly enlarged. In both experimental and control animals, we noted cyst formation in rests of Malassez. No signs of periodontal infection were observed. It is concluded that cathepsin C deficiency does not lead to major changes in the structure of the periodontium.

Alveolar Process↗
PubMed1996

Keratinocyte integrins in wound healing and chronic inflammation of the human periodontium.

Periodontal epithelium plays a critical role in protection, destruction and repair of human periodontium. During optimal repair, epithelium migrates and covers the wound surface to prevent infection and damage of the vulnerable underlying connective tissue. During periodontal destruction, junctional epithelium undergoes transformation to pocket epithelium that has quite different characteristics from junctional epithelium. In the course of periodontal disease the epithelial attachment to the tooth surface is lost and the epithelium proliferates and extends pseudo-rete ridges deep into the inflamed connective tissue. Both scenarios, repair and destruction, involve active epithelial migration either in the wound provisional matrix or in the inflamed connective tissue matrix, respectively. This review covers recent research data on cellular receptors, integrins, that mediate epithelial cell migration during wound healing and destruction of human periodontium.

Basement Membrane↗
PubMed1977

Study of the noncollagenous components of the periodontium.

Periodontal ligament and gingivae of bovine and porcine periodontium were analyzed for relative amounts of carbohydrates, collagen, and acid mucopolysaccharides. The sugar content was 3.6% and 3.4% of dry weight in bovine and porcine periodontal ligament, respectively. The values were lower in the gingivae being 2.34% and 2.30%, respectively. Approximately 50% of hexosamine in gingivae was present in acid mucopolysacchrides as compared to 36% in periodontal ligament. Relative to collagen there was a considerable amount of non-collagenous glycoproteins present in the periodontium as judged by carbohydrate content of the tissue.

Animals↗
PubMed1981

Comparative collagen biochemistry of bovine periodontium, gingiva, and dental pulp.

Cross-linking patterns of the collagen from bovine gingiva, periodontium, and dental pulp were analyzed chromatographically. The ratios of two main cross-links, dihydroxylysinonorleucine to hydroxylysinonorlecuine, were 0.18, 0.31, and 0.49 for the bovine gingiva, periodontium, and dental pulp collagen, respectively. These ratios are similar to that of skin collagen rather than that of bone and dentin collagen.

Amino Acids↗
PubMed1994

Sex steroid hormones and cell dynamics in the periodontium.

The biological changes that occur in tissues of the periodontium during puberty, the menstrual cycle, pregnancy, menopause, and oral contraceptive use have heightened interest in the relationship between sex steroid hormones and periodontal health. These clinical observations coupled with tissue specificity of hormone localization, identification of hormone receptors, as well as the metabolism of hormones have strongly suggested that periodontal tissues are targets for androgens, estrogens, and progestins. The etiologies of periodontal endocrinopathies are diverse; nonetheless, periodontal pathologies may be a consequence of the actions and interactions of sex steroid hormones on specific cells found in the periodontium.

Contraceptives, Oral↗
PubMed2002

Expression of MMP-8 and MMP-13 mRNAs in rat periodontium during tooth eruption.

The present study was designed to investigate mRNA expression of matrix metalloproteinase-8 (MMP-8) and MMP-13 in forming periodontium during tooth eruption in the rat. RT-PCR for the decalcified paraffin sections indicated expression of MMP-8 and MMP-13 in the periodontal tissues. In situ hydridization demonstrated expression of MMP-8 in osteoblasts, osteocytes, periodontal ligament cells, cementoblasts, and cementocytes along with collagen types I and III. In contrast, transcripts of MMP-13 were confined to a small population of osteoblasts and osteocytes in alveolar bone. The results suggested that MMP-8 may be involved in remodeling the periodontium during tooth eruption, and its expression may be coordinated with that of collagen types I and III, whereas the participation of MMP-13 may be rather limited.

Alveolar Process↗
PubMed1993

Immunohistochemical localization of proteoglycans in human periodontium.

Proteoglycans (PGs) are extracellular and cell surface-associated macromolecules that regulate cell adhesion, cell growth, matrix formation, and bind growth factors. In this work we studied the distribution of core proteins of four PGs (decorin, biglycan, a large molecular weight PG, and CD44) in human gingiva and periodontal ligament by immunohistochemical staining of frozen tissue sections with specific antibodies. Decorin, a major PG of this tissue, was localized on collagen fiber bundles in the gingival and periodontal connective tissues. Staining for decorin was most intense at the subepithelial region. Biglycan was a minor PG component of the human periodontium, showing some accumulation in connective tissue under the oral epithelium. At the immunohistochemical level, biglycan appeared to form fine filament-like structures on extracellular matrix fibers. Localization of large molecular weight PG differed from that of decorin and biglycan. It was concentrated in deep connective tissue areas of the gingiva and in the periodontal ligament, and was only weakly present at the subepithelial region. CD44 was mainly concentrated in cell-cell contact areas of basal and spinous layers of oral epithelium. In the connective tissue of gingiva and periodontal ligament, CD44 was localized on fibroblast cell surfaces. Connective tissue area under the junctional epithelium contained relatively small amounts of PGs. The results indicate that different parts of human periodontium contain a typical variety of PGs, suggesting a specific function for each PG species in the location at which they accumulate.

Adolescent↗
PubMedDate not supplied

[Development of a periodontium-approximated specimen holder for attrition studies of telescopic crowns].

To enable attritional studies on telescopic crowns, a specimen holder has been constructed that is intended to simulate, in zero approximation, the biomechanical properties of abutments bearing telescopic crowns. The specimen holder consists essentially of a system with two metal "concertinas" with different elasticity constants reflecting the different biomechanical parameters for periodontium and bone. The biomechanical processes in the periodontium are too complex to be simulated accurately in vitro. Nevertheless, the specimen holder described here enables the forces acting during insertion and removal of a partial denture to be accommodated elastically in the angular and axial directions, to simulate the possible degrees of freedom of the abutments in situ. In this way, the unavoidable errors of specimen fixation are rendered tolerable, so that local preferential wear is decisively reduced.

Alveolar Process↗
PubMed1987

Periodontium destruction associated with oncology therapy. Five case reports.

Radiation treatment to the head and neck and cytotoxic chemotherapy can produce deleterious side effects to the periodontium that are generally transient in nature, reversible, and do not result in permanently visible defects. However, combinations of the malignant disease itself, the direct and indirect effects of medical therapy and associated oral infections, along with local trauma can lead to periodontal tissue destruction with resulting permanent architectural defects. Five case reports illustrate destructive alterations of the periodontium that were associated with oncology therapy. Proposed guidelines for periodontal treatment of compromised individuals undergoing oncology therapies are suggested.

Adult↗
PubMed1989

[Effects of the soft diet on the periodontium and the leukocyte functions of the beige mouse].

The Chédiak-Higashi (C-H) syndrome in man and certain animals including the beige mouse in a genetic disorder (autosomal recessive disease) characterized by partial oculocutaneous albinism, photophobia, recurrent infections and defective leukocyte function manifested by the presence of abnormally large lysosome-like organelles in granule-containing cells. The oral manifestations that have been reported include severe gingivitis, ulcerations, and early, severe, periodontal break-down. The beige mouse is analogous to the C-H syndrome in man. This study was conducted determine the effects of diet (soft diet) on the periodontium and leukocyte functions of beige mice by observing the periodontium and the activity of the cells. Beige mice and their heterozygous male littermates (hetero mice) were used at the age of 4-24 weeks and the lower jaw and neutrophils, macrophages and lymphocytes were used. There was no significant difference histologically between the beige mice and hetero mice at the age of 24 weeks when that were fed a hard diet. But, when they were fed the soft diet for 4 weeks, bone resorption was seen in the beige mice, but not in the hetero mice. All tested cell activities of the beige mice were significantly lower than those of the hetero mice. The above findings, suggest that there was a correlation between the decreased activity of the inflammatory cells and bone resorption in the mice fed the soft diet.

Animals↗
PubMedDate not supplied

Morphological examinations of hard tissues of periodontium and evaluation of selected processes of lipid peroxidation in blood serum of rats in the course of experimental periodontitis.

The problem of teeth loss as a result of periodontitis is growing continuously. In the study we aimed to show the correlation between the disease and lipid metabolism disorders. We performed morphological examinations of hard tissues of rats' periodontium in the course of experimental ligature-induced periodontitis and we demonstrated the destruction of alveolodental ligament. The following changes were observed: degenerative changes including necrosis within periodontium, progressive destruction of bone mass of alveolar process of the mandible in the region of inflammatory infiltration. Simultaneously, biochemical examinations of blood serum were performed revealing decrease of basic antioxidant enzymes activities: SOD, GSH-Px, GSH-R with simultaneous increase of MDA--the final product of lipid peroxidation.

Animals↗
PubMed2002

[Expression of IL-6 and it's mRNA transcription in the process of rat periodontium remodeling influenced by various bite forces].

OBJECTIVE: To study the expression of IL-6 in periodontal ligament fibroblasts (PLF) and osteoblasts in order to explain the molecular mechanism of the bite forte on periodontium remodeling. METHODS: A rat model of different bite forces was established to study the expression of IL-6 and IL-6 mRNA in the PLF and osteoblasts with immunohistochemical (IHC) and in situ hybridization (ISH) techniques. RESULTS: In the group of disuse bite force, the expression of IL-6 and IL-6 mRNA in the PLF and osteoblasts enhanced apparently compared with that in the group of normal bite force. The gray level values enhanced respectively from 6.5886 +/- 1.6 to 38.8381 +/- 9.5 and from 11.8337 +/- 2.8 to 57.2623 +/- 13.6. The loosely arrangement of periodontal fibers and the resorption of alveolar bone were observed in histological study. In the group of compensation bite force, the same result was observed with IHC and ISH, the gray level values enhanced respectively from 6.3119 +/- 1.5 to 45.5456 +/- 11.1 and from 11.7714 +/- 2.8 to 81.9391 +/- 19.5, but the increase of periodontal fibers, the resorption and formation of alveolar bone were observed simultaneity in histological study. CONCLUSIONS: With the change of bite force, the expression of IL-6 and IL-6 mRNA in PLF and osteoblasts presents a certain regulation. IL-6 may play important roles in the effect of bite force on periodontium remodeling.

Animals↗
PubMed2003

[Effect of smoking on the periodontium and the level of aspartate aminotransferase in gingival cervical fluid].

OBJECTIVE: To study the effect of smoking on the periodontium and level of aspartate aminotransferase in gingival cervical fluid (GCF-AST). METHODS: A proportion matched case-control filtration was performed in examined population, college students, outpatients from 1999 May to 2001 March 115 smokers aged from 23 to 65 years (102 men and 13 women) and 90 non-smokers aged from 25 to 70 years (80 men and 10 women) were chosen. Debris index (DI), calculus index (CI), periodontal disease index (PDI), GCF-AST were measured. RESULTS: No obvious differences were observed in DI in smokers (0 degrees, 27.2%; 5 degrees, 5.0%) and non-smokers (0 degrees, 27.8%; 5 degrees, 4.2%),whereas obvious differences were found in CI in smokers and non-smokers. The percentages of patients without calculus were lower in smokers (9.8%) than in non-smokers (20.0%). The percentages of patients with weighty calculus were higher in smokers (25.4%) than in non-smokers (12.8%). The PDI values in smokers were higher than in non-smokers. The percentages of their normal periodontium were lower in smokers (9.6%) than in non-smokers (20.8%). The percentages of their periodontitis were higher in smokers (38.5%) than in non-smokers (25.8%). The smoking quantity were positively related to periodontitis (P < 0.001). No obvious differences were found in the level of GCF-AST with same PDI (P > 0.05). CONCLUSION: Smoking is considered as one of the risk factors in the prevalence of periodontal disease, but may not have any direct effect on GCF-AST.

Adult↗
PubMed2005

[Changes to the periodontium in postmenopausal women].

Few up to date studies on the influence of hormonal replacement therapy (HRT) on periodontium has been conducted on small groups of patients and the conclusions made may require further investigation on a larger population. It has been widely accepted that decreased estrogen levels in postmenopausal women are associated with a gradual loss of a bone density and increased risk of a dental loss. Much less stress is put however on the fact that the same phenomenon, especially suboptimal levels of estradiol, may deteriorate periodontal tissue condition. The authors made a literature search on the influence of HRT on periodontium.

Age Factors↗
PubMed2005

[Effect of bite force lost on the expression of iNOS in the rat periodontium].

PURPOSE: To investigate the molecular mechanism of the effect of bite force loss on periodontium remodeling. METHODS: For establishing a rat model of different bite forces for the study, the left maxillary molars of Wistar rats were extracted and the left mandibular molar area was used as the model of the bite force lost. The animals were sacrificed after 6 hours,1,2,3 days and 1,2,3,4weeks. The prepared tissue specimens were processed for the study of the change in the histologic morphology and the expression of iNOS protein in PDLC and osteoblasts with HE staining, immunohistochemistry and RT-PCR techniques, and the results were analyzed by one-way ANOVA,Dunnet t test and paired samples test. RESULTS: In the group of lost biting force, the derangement of periodontal ligament and resorption of alveolar bone were observed in histologic study: the structure of periodontal ligament deranged ,fibers and cells arrayed abnormally, there were many holes in the alveolar bone, even osteoclasts were present; the expression of iNOS was observed dramatically changed: the expression of iNOS in periodontal ligament fibroblasts and osteoblasts was higher than normal, especially at 2 days and 3 weeks,so as the results of RT-PCR.There was a significant correlation between bite force lost and the increased expression of iNOSmRNA. CONCLUSIONS: Bite force lost significantly increased the expression of iNOSmRNA in PDLC and osteoblasts, which suggests that iNOS may play an important role in the process of periodontium remodeling.

Alveolar Bone Loss↗
PubMedDate not supplied

[Experimental research on the stresses in roots with a pin "stump" structural element and in the periodontium of the masticatory teeth using a photoelasticity method].

The photoelasticity method, that discloses the physical essence and the mechanism of the emergence of stress fields in the periodontium, was used to study the strained status of the pin 'stump' design-root-periodontium-well system in flat models with a conditioned root shape 6 perpendicular to 6; various methods of cavity preparation were used, and occlusion was exposed to different combined and solitary vertical forces. Analysis of the findings helps define the optimal methods for cavity preparation and the geometry of the pin 'stump' design from the strained deformed status of certain sites. The authors have for the first time developed a method for simulation of contact strain fields and revealed a relationship that can be calculated from simulated designs to natural ones.

Biomechanical Phenomena↗
PubMedDate not supplied

[The periodontium in experimental bruxism].

Time course of morphologic changes in periodontal tissue was studied in 42 miniature pigs with experimental bruxism. An inflammation has developed in the marginal periodontium. At first the inflammatory infiltrate was situated under the epithelial fixation to the tooth involving destruction of the epithelial fixation and formation of pockets, inflammatory infiltrate, and granulation tissue, these destructive changes involving the lower sections of the periodontium. Signs of resorption were detectable in the dental alveolus osseous wall, cement, and dentin. The changes in the periodontal tissue described above appear to result from a complex of factors developing in experimental animals with simulated bruxism.

Alveolar Process↗
PubMed1990

[Collagen as a basic element of the periodontium: immunohistochemical aspects in the human and animal. 1. Gingiva and alveolar bone].

The connective tissue (CT) is responsible for stability and function of the whole periodontium. It consists of cells, which are embedded in the extracellular matrix. Collagen plays the main role for the function of the periodontal unit. Collagen types I, III, IV, V and VI are distributed in a different pattern in all periodontal tissues, as has been here demonstrated in the gingiva and alveolar bone. Collagen type I, as a characteristic collagen type of the hard tissues, has been demonstrated by thick collagen fibers in the alveolar bone and in the gingival connective tissue. It can be differentiated from the thinner collagen type III fibers, which are localized in the gingiva (especially under the basement membrane of the epithelium) as well as only in the bone marrow stroma. The epithelium, blood vessels and nerves contain the characteristic collagen type IV in their basement membrane Filamentous (collagen type V) and microfibrillar (collagen type VI) components demonstrate different patterns of distribution, especially around the bone cells and in contrast to the other collagen types of fibrillar networks in the gingival CT. This morphological differentiation of the extracellular matrix components of the periodontium allows conclusions in the pathological and inflammatory processes as well as in the regenerative and reparative procedures.

Alveolar Process↗