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Connective tissues of the periodontium. Research and clinical implications.

The periodontium is a complex anatomical site composed of a variety of hard and soft connective tissues. The site is subjected to enormous daily chemical and mechanical abuse, yet, for the most part remains relatively intact. Nonetheless, when breakdown does occur, the ability of the periodontium to regenerate is sometimes limited. This review considers the various components of the periodontium and how they might be involved in not only the pathology of periodontal diseases but also the various reparative and regenerative processes required during wound healing. In addition, the importance of external factors such as a variety of commonly prescribed medications on these events is discussed.

Connective Tissue↗

Effects of endogenous sex hormones on the periodontium--review of literature.

Hormones are specific regulatory molecules that have potent effects on the major determinants of the development and the integrity of the skeleton and oral cavity including periodontal tissues. It is clear that periodontal manifestations occur when an imbalance of these steroid hormones take place. The authors conducted a Medline search up to 2004 and in addition, a manual search was also performed including bibliographies of relevant papers, review articles and books. This review focuses on the effects of endogenous sex hormones on the periodontium and the goal was to inform and update practitioners' knowledge about the impact of these hormones on periodontal status. In addition, this review article will analyze how these hormones influence the periodontium at different life stages such as puberty, menstruation, pregnancy, menopause and post-menopause. Moreover, the effects of contraceptives and hormone replacement therapies on the periodontium will be discussed. It is clear that endogenous sex steroid hormones play significant roles in modulating the periodontal tissue responses. A better understanding of the periodontal changes to varying hormonal levels throughout life can help the dental practitioner in diagnosis and treatment.

Contraceptives, Oral, Hormonal↗

The sensory innervation of the periodontium of the third premolar in Monodelphis domestica.

Location and structure of sensory nerve endings in the periodontium of the third premolar in Monodelphis domestica have been investigated by means of light and electron microscopy. The periodontal cleft of the tooth is apically enlarged. The number of nerve endings increases towards apex. Three types of sensory nerve endings have been observed: free nerve endings, Ruffini nerve endings and lamellated corpuscles. Free nerve endings could only be identified by electron microscopy. Ruffini nerve endings are only incompletely surrounded by lamellae of the terminal Schwann cell. Protrusions of nerve terminals of the Ruffini corpuscles are anchored between bundles of collagen fibers. Small lamellated corpuscles occur exclusively in the apical portion of the periodontium. Ruffini and lamellated corpuscles are considered as part of a masticatory reflex feedback control system. Ruffini corpuscles detect tension, rapidly adapting lamellated corpuscles detect pressure and vibration in the periodontium. Free nerve endings may function as thermoreceptor or nociceptor.

Animals↗

Retained "hopeless" teeth: lack of effect periodontally-treated teeth have on the proximal periodontium of adjacent teeth 8-years later.

We previously reported the lack of effect periodontally-treated teeth prognosed "hopeless" and retained for 3.4 +/- 1.5 years have on the proximal periodontium of adjacent teeth. We now report our findings for the same group of subjects following 8.4 +/- 0.7 years of "hopeless" tooth retention. Of the 17 "hopeless" and adjacent teeth originally measured in 17 subjects, 14 of the subjects were still available for re-evaluation. Measures used to assess the periodontium of proximal surfaces of adjacent teeth included pocket depths (PD), radiographic alveolar bone level (R-BL), and periodontal ligament space width (W-PL). Treatment for the subjects consisted of surgical therapy (N = 15) and scaling and root planing (N = 2). Of the 14 subjects re-examined, 2 were eliminated due to loss of adjacent tooth reference points and 2 due to extraction of the "hopeless" tooth (N = 10). Differences in measurements (i.e., nonadjacent to "hopeless" tooth value minus adjacent to "hopeless" tooth value) were analyzed using a repeated measures ANOVA. There were no significant differences for PD (P = 0.20), R-BL (P = 0.29), or W-PL (P = 0.16). These data confirm our original findings that retained periodontally "hopeless" teeth do not significantly affect the proximal periodontium of adjacent teeth following therapy.

Alveolar Bone Loss↗

[Hemodynamic changes in the periodontium with the use of chewing gum].

The effect of gum chewing (5 min after meals 3 times a day) on periodontal blood supply was studied in a group of 52 volunteers with different clinical status of the periodontium. Tonic strain in the local vessels changed (fluctuated) little (by 2-7%). Tonic strain was shifted on the inert side and in patients with periodontal diseases. Blood consumption increased by 33%. Regular gum chewing for 10 min resulted in compensatory vasoconstriction and hyperemia of the periodontium starting from the second week, irrespective of the initial clinical status of the periodontium.

Chewing Gum↗

Effect of loss of bite force on interleukin-1beta expression in rat periodontium.

OBJECTIVE: To study the expression of interleukin-1beta(IL-1beta) in the fibroblasts and osteoblasts in the periodontal ligament cells(PDLC) of normal rats and rats with loss of bite force, to explain the molecular mechanism of periodontium remodeling. METHODS: Rat models of lost bite force were established using Wistar rats. The changes in the histological morphology of the periodontium and the expression of IL-1beta in the PDLC and osteoblasts were observed in both normal rats and the rat models using HE staining and immunohistochemistry techniques. RESULTS: In rat models of lost bite force, the periodontal ligament structure appeared to be disorganized and absorption occurred in the alveolar bone. The expression level of IL-1beta in the PDLC and osteoblasts was significantly enhanced in comparison with that in the normal rats, as demonstrated by immunohistochemical study. CONCLUSION: Loss of bite force may induce structural disorganization of the periodontal ligament and absorption in the alveolar bone, and the expression level of IL-1beta in PDLC and osteoblasts show significant elevation, indicating that the changes in histological morphology is closely coordinated with the functional changes in the periodontium.

Animals↗

Effects of the multiple-piece maxillary osteotomy on the periodontium.

Clinical indications exist for both the surgically assisted rapid maxillary expansion (SARME) and the multiple-piece maxillary osteotomy (MPMO). Recent trends, however, imply that the SARME combined with a subsequent 1-piece osteotomy can supplant the use of the MPMO. Those favoring the SARME frequently site morbidities associated with the MPMO. Major reported complications include loss of dentoalveolar segments, teeth, and oronasal or oroantral communication. Relapse, tooth devitalization, and damage to the periodontium, including bone loss and soft tissue alteration, comprise the minor morbidities. If these can be avoided or minimized, then the use of the MPMO for its inherent advantages over the SARME in certain clinical situations may be indicated The purpose of our study was to critically evaluate the periodontium following the use of the MPMO to ascertain if minor morbidities are inherent to the procedure, and to quantify them. Records of 24 MPMO patients were reviewed, ranging from 3 to 24 months after surgery. A specific surgical technique was utilized for all patients, including bone grafting. The vertical segmental osteotomy sites varied and were recorded for comparison. Periodontal probing depths at the segmental osteotomy sites were compared with the adjacent interproximal spaces of each patient. Independent dental examiners were used to review photographs and periapical radiographs to compare the papillae and alveolar bone height, respectively, at the osteotomy site versus the neighboring interproximal areas. A paired t test was used to compare probing depth measurements at the vertical osteotomy site and neighboring interproximal sites. The mean difference between these two sites was 0.01 mm with a standard deviation of 0.25 mm. This was not statistically significant. Statistical analyses were also performed to compare these probing depth differences at varying sites in the maxilla, and to compare probing depth differences to gender, total number of osteotomies performed on each patient, estimated blood loss, and length of procedure. These results were not statistically significant. Independent examiners found no difference in gingival architecture or alveolar bone levels when comparing vertical osteotomy sites to neighboring interproximal sites. This study showed that damage to the periodontium at vertical osteotomy sites was minimal, and not a reason to avoid use of the multiple-piece maxillary osteotomy.

Adolescent↗

[Effects of bite force lost on the expression of IL-6 in the rat periodontium].

OBJECTIVE: In order to explain the molecular mechanism of periodontium remodeling the expression of IL-6 in the rat periodontal ligament fibroblasts (PDLC) and the alveolar bone osteoblasts under normal and bite force lost was studied. METHODS: To establish a rat model of different bite force for the study, left maxillary molars of rats were extracted and the left mandibular molar area was used as the bite force lost. The animals were sacrificed after 6 hours, 1, 2, 3 days and 1, 2, 3, 4 weeks. The prepared tissue specimens were processed for the study of the change in the histologic morphology and the expression of IL-6 protein in PDLC and osteoblasts with HE staining and immunohistochemistry techniques. RESULTS: In the group of bite force lost, the loosely arrangement of periodontal ligaments and the resorption of alveolar bone were observed in histological study, the expression of IL-6 in PDLC and osteoblasts was enhanced apparently than that in the group of normal bite force by using immunohistochemistry techniques. In the group of lost bite force, the expression of IL-6 in PDLC enhanced with time regularly: The expression of IL-6 was strengthened after 3 days, and reached the peak after 2 weeks, then, decreased after that and restored to normality in 4 weeks. While in osteoblasts of the group of bite force lost, the expression of IL-6 was strengthened just after 2 weeks. CONCLUSION: Bite force lost induce the expression of IL-6 enhanced apparently in PDLC and osteoblasts, it suggests that IL-6 may play important roles in the effect of bite force on periodontium remodeling. It approaches initially the molecular mechanism of periodontium remodeling, demonstrates that the histologic morphology is closely related to the mechanical condition.

Alveolar Bone Loss↗

[Changes of dentin, dental pulp and periodontium tissue in tail-suspended rats].

OBJECTIVE: To investigate the metabolic changes of calcium and phosphorus in dentin, dental pulp and periodontium in tail-suspended rats, and the functions of TGF-beta 1, c-fos, collagen-I and collagen IV in dentin, dental pulp and periodontium. METHOD: Relative percentage contents of Ca, P in dentin, dental pulp and periodontium were measured with scanning electron microscope and energy spectrum analytical system in 3 groups of rats. The expression of TGF-beta 1, c-fos, collagen-I and collagen IV were also observed. RESULT: In the suspension group, the relative percentage content of Ca declined significantly, while P increased slightly. There were no significant differences of Ca, P in alveolar bone. The expressions of TGF-beta 1, c-fos and collagen-I declined, but the expression of collagen-IV in pulp vessel increased. There were no significant changes of expressions of TGF-beta 1, c-fos, collagen-I and collagen-IV in the vicinity of PDL. After adopting artificial countermeasures, the above expressions restored partly. CONCLUSION: Weightlessness might cause abnormal mineralization in dentin, and 1.5 G artificial countermeasures could eliminate the above changes of mineral metabolism. The poor mineralization of dentin might be associated with the reduced secretion of TGF-beta 1, c-fos and collagen-I in tail-suspended rats.

Animals↗

[The systemic circulation and microcirculation of the periodontium vital microscopy and histological studies of incisors of rats (author's transl)].

A new classification of the angioarchitecture and blood flow is proposed in light of the results of vital microscopy studies of the windowed periodontium and gingiva of the incisors of rats. The flow pattern and the rate of blood flow are different in different vessels. The flow of blood in segmented and interconnected arterial and venous vascular sections in the alveolar and marginal periodontium corresponds to what is known as systemic circulation, whereas that in arterioles, capillaries, and venoles must be considered as belonging to what is referred to as microcirculation. Subepithelially, the microcirculatory elements constitute a nutritive, typically ordered capillary network as contrasted with the random spatial arrangement of capillary loops in the alveolar periodontium. Numerous anastomoses provide the basis for possible functional adaptation, leading to the formation of polygonal ring closures in the alveolar region. The interpretations of functional findings are based upon histotopological reexaminations.

Alveolar Process↗

[Functional characteristics of periodontium sensing apparatus and its significance in prosthetic stomatologic clinic].

Using developed by us method and instrument Periosensomer the sensor function of the periodontium on the initial stages of masticatory act (test of holding and splitting of food object) in persons with different functional periodontium status was explored. Evaluation of the sensor function of the periodontium and dynamics of the sensor reaction during holding and splitting of food object can be used as the method of functional diagnostics in the prosthetic stomatological clinic.

Adult↗

[Structural changes in the collagen fibers of the connective tissue in chronic inflammation in the periodontium].

Data of examinations of the periodontium during chronic inflammations are analyzed. Immunohistochemical studies revealed that the connective-tissue cicatrix forming in the course of reparative regeneration of the periodontium is immature and incapable of performing mechanical functions. The authors suggest that the above regeneration abnormalities lead to a relapsing occlusion injury of the periodontium and progress of the inflammatory sclerotic process. Perspective trends of the patho- and morphogenetic research of chronic periodontitis are outlined, as are the probable theoretical approaches to development of methods for correction of such abnormalities.

Adult↗

Patterns of cytokeratin expression in monkey and human periodontium following regenerative and conventional periodontal surgery.

The pattern of cytokeratin expression has been extensively described in the normal and inflamed periodontium. However, there is no information regarding the pattern of cytokeratin expression in the periodontium which has been reformed following regenerative periodontal surgery. The aim of the present investigation was to evaluate the pattern of cytokeratin expression in the reformed human and monkey periodontium following regenerative and conventional periodontal surgery. In 3 monkeys, acute fenestration-type and chronic intrabony defects were treated with guided tissue regeneration (GTR), enamel matrix proteins (EMD), or coronally repositioned flap surgery (control). After a healing period of 5 months, the animals were sacrificed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA and embedded in paraffin. Histological sections were cut with the microtome set at 3 microm. The sections were alternatively stained either with hematoxylin and eosin, or immunohistochemically by using one of the broad range monoclonal antibodies 34betaE 12 (for cytokeratins 1, 5, 10 and 14) or KL 1 (for cytokeratins 1, 2, 5, 6, 7, 8, 10, 11, 16 and 19), or one of the individual monoclonal antibodies LL025 (for cytokeratin 16), DC 10 (for cytokeratin 18), A53-B/A2 (for cytokeratin 19). Twelve patients, each displaying one deep intrabony defect scheduled for extraction due to advanced periodontitis or prosthetic reasons, were treated as described above. Following a healing period of 6 months, the teeth were extracted together with some of their surrounding soft and hard tissues. The histological and immunohistochemical processing of the human biopsies was identical to that described in monkeys. The results revealed that both the normal non-treated (original) monkey and human junctional epithelium stained strongly with all of the monoclonal antibodies used. The reformed junctional epithelium displayed the same cytokeratin expression pattern as the non-treated junctional epithelium. No differences regarding the cytokeratin expression pattern of the junctional epithelium were found between the treatments and types of healing (i.e. regenerative, through a new periodontal ligament, or reparative through a long junctional epithelium). In the intact periodontal ligament, the epithelial rests of Malassez displayed a comparable cytokeratin expression pattern to that of the junctional epithelium. However, no expression of cytokeratins was seen in the newly formed periodontal ligament. In such specimens, cytokeratin expression was observed only until the borderline between the regenerated cementum and the epithelial downgrowth. It was concluded that: a) the reformed junctional epithelium, following any type of surgical procedure, displays a similar pattern of cytokeratin expression to the original junctional epithelium; b) in the newly formed periodontal ligament, no expression of cytokeratins is present; and c) the epithelial rests of Malassez do not seem to reform after regenerative periodontal surgery.

Alveolar Bone Loss↗

Emdogain regulation of cellular differentiation in wounded rat periodontium.

Emdogain is an enamel matrix derivative that may promote periodontal regeneration by recapitulating critical events in tooth morphogenesis. We hypothesized that Emdogain enhances periodontal regeneration by promoting the differentiation of cells required for the synthesis of periodontal ligament, bone and cementum. Cell differentiation was examined in rat periodontal window wounds in which there is no microbial biofilm or epithelial downgrowth, thereby simplifying the model system. Defects were filled with vehicle control or Emdogain (3 mg/ml or 30 mg/ml). Rats were sacrificed at 7, 14 and 21 d after wounding. Specimens of periodontium were immunostained for osteopontin, bone sialoprotein, osteocalcin as markers of osteogenic differentiation and for alpha-smooth muscle actin, a myofibroblastic marker. Morphometry and 3H-proline radioautography were used for assessment of tissue homeostasis and matrix production. Rats treated with Emdogain (only at 30 mg/ml) showed widening of the periodontal ligament at 7 d; by 14 and 21 d, periodontal ligament width was restored to normal values for all groups. Emdogain exerted no effect on cementum thickness, bone volume, osteoid deposition rates, or extracellular staining for osteopontin, bone sialoprotein or osteocalcin. Further, the percentage of cells with intracellular staining for osteopontin, osteocalcin or bone sialoprotein was unaffected by Emdogain. Staining for alpha-smooth muscle actin was abundant in the repopulating wound but was also unaffected by Emdogain. In conclusion, Emdogain does not apparently affect the expression of differentiation markers or bone matrix protein synthesis in the repopulation response of wounded rat molar periodontium. Therefore the effect of Emdogain on wound healing in the periodontium may be independent of differentiation in the cell populations examined in this model.

Actins↗

Squamous odontogenic tumor (SOT): a benign neoplasm of the periodontium. A review of 36 reported cases.

True neoplasms are rarely localised to the periodontium. However, early recognition and diagnosis of neoplastic lesions resides within the realm of responsibility of the dentist. In recent years, a number of odontogenic tumors has been described characterized by an occurrence on the gingiva or in the intrabony part of the periodontium. One such neoplasm, the squamous odontogenic tumor (SOT) originally described 20 years ago is now a well-recognized entity localized to the periodontium, be it in the periodontal ligament or in the gingivae. A review of 36 acceptable cases of this tumor published sofar, forms the basis of the present paper.

Adolescent↗

[Clinical evaluation of periodontium in pregnant women with risk of preterm birth].

OBJECTIVES: The aim of the study was to evaluate condition of the periodontium in pregnant women with pathological progress of the pregnancy, clinically and to compare it to periodontium in pregnant women in good health. DESIGN: Over the last years, the studies have described that periodontitis caused by dental plaque, could be the risk factor for preterm birth and low birth weight. MATERIALS AND METHODS: This study was performed in 80 pregnant women, 40 with pathologic pregnancy and 40 with normal pregnancy in it. Periodontal Indexes were used to evaluate periodontium. RESULTS: In the searching group gingivitis gravidarum haemorrhagica diffusa and hyperplastica generalisata were dominating. In the control group gingivitis gravidatum simplex and hyperplastica localisata were observed. CONCLUSIONS: More severe manifestation of gingivitis gravidarum was noticed in pregnant women with risk of preterm low birth. We did not prove correlation between amount of bacterial dental plaque in pregnant women and risk of preterm low birth weight.

Adult↗

Periodontium and vitamin E and A in pregnancy.

The evaluation of the clinical condition of periodontium by means of the epidemiological indexes and the level of oral hygiene in two weeks intervals in the course of physiological pregnancy in 39 women in good general health revealed the maximum of inflammatory changes of periodontium in the 8th month of pregnancy with the amelioration shortly before delivery. Simultaneous follow-up of the physiological levels of vitamin E and A in four weeks intervals showed the decline of the mean levels of both vitamins in the course of the 8th month and their marked elevation shortly before delivery; therefore remains questionable, if this elevation reaching over their physiological range, contributes to the amelioration of the condition of periodontium observed at the same time.

Female↗

[Evaluation of periodontium status and periodontal needs in persons aged 35-44 years in Poland].

The aim of this study was providing current, objective and comparable with the world literature data on the frequency of occurrence and the intensity of periodontal diseases in the age group 35-44 years. During the surveys the WHO card from 1986 was used. The condition of periodontium the periodontal treatment needs were assessed by CPITN (Community Periodontal Index of Treatment Needs) with use of 621 WHO probe. One thousand three hundred and eighty persons in nine districts of Poland were examined, with regard to three living areas: big cities, small towns and the rural ones. The results of surveys accomplished in Poland indicate that the achievement of the second health purpose, designed by World Health Organization for the year 2000 in the field of periodontal tissues is unattainable. This is because, according to the second health purpose, 75% of the population at the age of 35-44 years ought to have three health sextants, and deep picketing can occur in maximum 5% of the population. Unfortunately, only in 7.1% of persons examined at least three healthy sextants were found. They were disclosed considerably more often in women (9.1%) than in men (5.1%). Deep periodontal pocketing of 6 mm and more were found in 15% of persons examined. They were detected considerably more frequently in men (18.4%) than in women (11.3%). By comparison of data pertaining to individual districts (Tab. 1-5), it turned out that the worst conditions of periodontium occurred in Białostockie, where there was not a single person with healthy periodontium. Better results were recorded in Gdańskie, which must be the effect of systematical health education. Periodontal treatment needs among the persons examined are enormous. Almost 100% of persons require both instruction of brushing teeth and time consuming professional procedures of removal of the concrement on the teeth. Fifteen per cent of the persons need specialized treatment. These proportions varied differently in the surveyed districts, only 5% in Dgańskie and from 21.7% to 23.9% in Białostockie, Wrocłlawskie and Krakowskie. However the proportions of those needs in Poland are much bigger than in other European countries, and differ considerably from the marked second periodontal health purpose for the year 2000.

Adult↗