The development of the vascular bed of the marginal periodontium

The vascular bed of the periodontum of rat molars develops from the vascular network of the alveolar mucosa, from the vascular network of the enamel organ and from vessels which, with the development of roots, form the bed of the periodontal membrane. Although these vascular areas form a unity in a developed periodontium, they retain their differences in arrangement. During the formation of the enamel, the bed of the enamel organ is arranged in rat molars and in the permanently growing rat incisor according to the same principles. In both types of teeth, the principles of this arrangement correspond with the metabolic needs of amelogenesis.     

The blood supply of the marginal periodontium in Macacus rhesus

The blood vessels supplying the periodontium was examined in corrosive preparations and histological sections. The vessels were arranged in two networks, those which supply the periodontal membrane and those which supply the gingiva. Although the two networks anastomosed in many sites, the capillaries in the periodontal membrane were arranged in a manner different from those in the gingiva, and the capillaries which arise in the vicinity of the epithelial attachment pursued a course different from both. The coiled arrangement of the capillaries is described and the role of the coiled structures discussed. It is postulated that they may be concerned in the nutrition of the tissues at the dento-gingival junction.     

Influence of pulpal treatments on cell and tissue reactions in the marginal periodontium

The effects of pulpal infection and intrapulpal application of calcium hydroxide and antibiotics were evaluated with special reference to cell and tissue reactions in the marginal hard/soft tissue interface in monkeys. Results indicate the pulpal conditions and endodontic dressings influence marginal healing and repair, provided an endodontic-periodontic pathway such as patent dentin tubules is present. These results suggest that permanent endodontic treatment, with an inert material, should be performed before the protective cementum layer is removed. Pulpally aggravated periodontal lesions should therefore not be overlooked in periodontal diagnosis and treatment.     

Studies on the biology of the periodontium of marmosets

Four adult cotton top marmosets fed a purified high cholesterol-high fat diet developed a malabsorption induced osteomalacia which involved the periodontal bone. The alveolar bone changes were denoted histologically by a narrowing and disruption of the cortical and cribriform plates and by the presence of broad bands of osteoid around the remaining compact and spongy bone elements. Radiographically, the changes were represented by a partial to complete loss of the lamina dura and by a greatly increased patch radiolucency of the mandible and maxilla.     

Studies on the biology of the periodontium of marmosets

Six adult cotton ear marmosets (Callithrix jacchus) fed a vitamin C-free synthetic diet of known composition developed overt evidence of ascorbic acid deficiency beginning 2 to 4 months after initiation of the test regimen. Three marmosets fed the identical diet plus a daily supplement of vitamin C served as controls. The animals were maintained on the vitamin C-free diet until they became moribund and were killed and necropsied. The control animals were sacrificed following the death of the last of the test group. Comparative gross and histologic examinations of the periodontal structures revealed striking changes in the periodontal ligament of the scorbutic marmosets with relatively minor alterations in the osseous and gingival components. The periodontal involvement was largely confined to the alveolar segment and consisted of ligamental hemorrhages, loss of ligamental compactness and density, reduction in number of attachment fibers and loosening of the teeth.     

Microradiography of the feline marginal periodontium with a microfocal high-resolution x-ray system

The present paper is a cross-sectional microradiographic study. Postmortem hemimandibles were radiographed with a microfocal high-resolution method. Microradiographic appearances of the feline periodontium are described and discussed. Mean relative alveolar bone support in clinically and histologically normal cats was 46.9%. Site-specific alveolar bone support (ABS) was calculated twice (blind). The 95% confidence limits of the method error for one observation were estimated. Differences between two site-specific measurements did not exceed ±2.72%. Microfocal radiography yielded valuable additional information about the feline periodontium and made it possible clearly to identify important dental and periodontal structures such as the CEJ (cementoenamel junction) and the bottom of infrabony defects.     

The condition of the periodontium in patients with clefts]

41 patients with total clefts, having an average age of 14.6 years, were examined. In these patients, the bone index was determined by means of the radiographic method of Schei et al. (as modified by Engelberger, Rateitschat and Marthaler). Furthermore, the teeth were tested for mobility, and the gingival retraction and the pocket depth were measured. The degree of gingival inflammation was scored using the PMA index according to Mühlemann and Mazor. The findings from the cleft quadrants were compared to those from the non-cleft quadrants of the upper jaw and to those from the mandibular quadrants.     

Loss of attachment in the marginal periodontium of the rat incisor under non-inflammatory conditions

Alkaline phosphatase (ALP) has been suggested to play a role in acellular cementum formation and maintenance of periodontal attachment. In an attempt to determine whether changes in attachment level are associated with altered expression of ALP-activity in the periodontium we induced natural loss of attachment in rats by pinning the lower incisor to the jaw bone. Previous studies have shown that this procedure results in regressive changes in the marginal periodontium without any inflammatory response. Six months after blockage of eruption the attachment level on the experimental (right) side had shifted about 700 μ in the apical direction. On the control (left) side the apical termination of the junctional epithelium had remained stationary with respect to the alveolar crest. Our observations have shown that during the first few weeks of the experiment loss of attachment is accompanied by considerable reduction of ALP-activity in the supracrestal part of the periodontium. At later time intervals, however, no distinct relation was found between apical migration of junctional epithelium and loss of ALP-activity in the supracrestal region, indicating that the two phenomena are not directly related to each other. The domain of the ALP-positive fibroblasts in the supracrestal extension of the periodontal ligament decreased in size and was replaced by ALP-negative connective tissue cells probably coming from the outer gingival domain. Since at all time intervals a distinct demarcation could be observed between the ALP-positive and ALP-negative areas, we interpret our data as indicating that ligament and gingival cells do not mix.     

Pathomorphological evaluation of the marginal periodontium in opioid-dependent patients (F 11.24)

Gingival mucosa of opioid-dependent patients (F 11.24) was studied by histological and morphological methods over the course of narcotization. Progressive inflammatory and destructive changes in the presence of regeneratory reactions (epithelial hyperkeratosis, lymphonuclear infiltration, and vascular sclerosis) were observed. The necessity of dental disease treatment in narcomaniacs is emphasized.