Histological and ultrastructural characteristics of the periodontal syndrome in the rice rat. III. Ultrastructural observations on changes in the transseptal fiber area and alveolar crest

Spontaneous repositioning of pathologically migrated teeth

BACKGROUND

There is limited clinical evidence that pathologically migrated teeth may reposition themselves after conventional periodontal treatment. The current research was carried out to determine the frequency of spontaneous repositioning of pathologically migrated teeth after routine periodontal therapy, and to study the relation between the severity of migration and the degree of repositioning following treatment.

METHODS

Sixteen patients with moderate to severe periodontal disease and presenting 33 diastema sites secondary to pathologic migration participated in this study. After conventional periodontal treatment had been performed, reactive repositioning was assessed by measuring the space between pathologically migrated teeth and adjacent teeth on study models obtained at baseline, re-evaluation at 6 weeks after scaling and root planing, and 4 months after surgery.

RESULTS

After scaling and root planing only, 48.5% of all sites exhibited some degree of repositioning with 36.4% of all sites closing completely. After surgery (6 months after baseline observations), 69.7% of all sites exhibited some degree of repositioning with 51.5% of all sites closing completely. When only small to moderate diastemata were considered (<1 mm), 77.8% of sites closed completely.

CONCLUSIONS

The findings of this study support the hypothesis that spontaneous repositioning after conventional periodontal treatment is likely, particularly when only light to moderate degrees of pathologic migration are considered. We hypothesize that this spontaneous movement is due to wound contraction during healing.

Gingivitis

Gingivitis is caused by substances derived from microbial plaque accumulating at or near the gingival sulcus; all other suspected local and systemic etiologic factors either enhance plaque accumulation or retention, or enhance the susceptibility of the gingival tissue to microbial attack. Microbial species specifically associated with gingival health include Streptococcus sanguis 1, S. D-7, and Fusobacterium naviforme. Bacteria involved in the etiology of gingivitis include specific species of Streptococcus, Fusobacterium, Actinomyces, Veillonella, and Treponema and possibly Bacteroides, Capnocytophaga, and Eikenella. Microbial colonization and participation is sequential, with the complexity of the associated flora increasing with time. The pathogenesis has been separated into the initial, early, and established stages, each with characteristic features. The initial lesion is an acute inflammation which can be induced experimentally by application of extracts of plaque bacteria to normal gingiva. The early lesion is characterized by a lymphoid cell infiltrate predominated by T lymphocytes, characteristic of lesions seen at sites of cell-mediated hypersensitivity reactions. The early lesion can be induced by application of purified contact antigens to the gingival tissues of previously sensitized animals. As the clinical condition worsens, the established lesion appears, predominated by B lymphocytes and plasma cells. Established lesions may remain stable for indefinite periods of time, they may revert, or they may progress. Periodontal destruction does not result from the conversion of a predominantly T cell to a predominantly B cell lesion as has been suggested, but rather from episodes of acute inflammation. Clinical manifestations of gingivitis are episodic phenomena characterized by discontinuous bursts of acute inflammation. Most lesions are transient or persistent but not progressive. Attachment loss may precede alveolar bone loss and may occur without the manifestations of a concurrent or a precursor gingivitis. On the other hand, the evidence indicates that a portion of gingivitis lesions can and does progress to periodontitis. Gingivitis and the periodontal microflora differ in children and adults. Clinical signs of gingivitis either do not appear as plaque accumulates, or they are greatly delayed in children, and the inflammatory infiltrate consists mostly of T lymphocytes. The conversion to a B cell lesion does not appear to occur. The evidence supports the conclusion that gingivitis is a disease, and that control and prevention is a worthwhile goal and a health benefit.(ABSTRACT TRUNCATED AT 400 WORDS)

Role of the polymorphonuclear leukocyte in periodontal health and disease

This review presents evidence for lysosomal enzymes being at least partly responsible for the tissue destruction seen in periodontal disease. However, many other inflammatory and immunologic mechanisms have been identified that can contribute to tissue destruction (Nisengard 1977). The relationship of PMN to the periodontal tissues is equivalent to the proverbial double-edged sword. The localized tissue destruction that may be due to the extracellular release of PMN enzymes in individuals with normal cell function must be weighed against the role of PMN in containment of gingival bacteria and their products. The consequences of qualitative and/or quantitative abnormalities of neutrophils are far more undesirable for the periodontium. It therefore seems logical to propose that the role of polymorphonuclear leukocytes in the gingival tissues is primarily a defensive one. The presence of neutrophils in the gingival crevice has been shown to reflect the inflammatory condition of the tissues. Due to their availability, it may prove beneficial to use gingival crevicular PMN activity as a reliable clinical index of disease activity. The development of appropriate tests to measure PMN may eventually lead to better diagnostic criteria, including the definition of active versus inactive disease.

Current concepts of the dentogingival junction: the epithelial and connective tissue attachments to the tooth

This review leads to a concept in which the tissues of the dentogingival junction are dynamic rather that static. Even when they are pathologic, they can be reconstituted by repair. Both their cellular and extracellular components exhibit a high rate of turnover. Some of the cells are specialized for specific functions, such as attachment formation, and do not generate additional cells, but generative pools are always nearby. The cells are capable of movement and of positional change. The junctional epithelium can advance and retract. The cuticle width is alterable. The entire tissue is capable of regeneration after wounding. This dynamic group of tissues is well adapted for the healing of direct injuries produced during mastication. The tissues do remarkably well, over long periods, in their response to periodontal disease, whether due to direct bacterial or toxic damage, or to indirect damage via the migration of inflammatory cells into the lesion. The tissues show a capacity for repair and regeneration following the elimination of plaque formation and the resultant resolution of the inflammatory infiltrate. The complete story is not yet developed. The past 60 years are replete with fine contributions by distinguished workers. Additional contributions continue to be made. The inheritance from our predecessors has been used well and our expanded knowledge in this area now serves as the conceptual framework for further study.