Osteopromotion: a soft-tissue exclusion principle using a membrane for bone healing and bone neogenesis.

The research reviewed in this paper constitutes a series of investigations intended to develop and evaluate a new membrane technique, which provides improved conditions for osteogenesis during healing of bone defects and restitution of earlier existing bone. The technique has also been shown to aid in bone grafting as well as having the capacity to create new bone for reconstructive purposes. According to this methodology, membranes are utilized to create a space in the tissue in which osteogenesis can occur relatively unimpeded. The paper provides a review of our initial animal experimental work as well as some clinical studies with special emphasis on membrane use in conjunction with dental implants. Possible mechanisms behind the efficacy of the membrane technique are reviewed, and future perspectives of development are also discussed. The osteopromotive membrane technique represents a principally new and major advance in bone biology and reconstructive skeletal surgery. Based on the results obtained by us and by others, the technique is presently utilized clinically in some routine applications.

A 4-quadrant comparative study of periodontal treatment using tetracycline-containing drug delivery fibers and scaling.

The present study describes results on selected clinical and microbiological parameters obtained by periodontal treatment with ethylene vinyl acetate fibers containing 25% by weight tetracycline hydrochloride placed into the periodontal pocket alone or in combination with scaling. Supragingival plaque control was maintained throughout the study by weekly professional cleaning and 0.2% chlorhexidine mouthrinses. Controls included untreated sites and sites treated by conventional scaling alone in a 4-quadrant split-mouth design. The experiment was conducted on 95 teeth from 10 subjects with periodontal pockets greater than or equal to 6 mm which initially bled on probing. All treatments resulted in changes indicative of effective therapy. Pocket depth was reduced, bleeding on probing decreased and gingival index scores decreased. Parallel to the clinical changes, all treatments reduced total bacterial numbers, % black-pigmented Bacteroides, motile bacteria, non-motile rods, and produced a proportionate increase in cocci. Fiber therapy with or without scaling reduced bacterial counts by approximately 2 orders of magnitude when evaluated at 62 days post-therapy. The combination of fiber therapy with scaling was particularly effective, suggesting a possible synergy between these forms of therapy. The combined therapy eliminated bleeding on probing, and black-pigmented Bacteroides, and produced the greatest mean reduction in pocket depth.

Nitrendipine-induced gingival overgrowth in dogs.

This study assessed the development of gingival overgrowth in dogs given nitrendipine, a new antihypertensive dihydropyridine. Nine male Beagle dogs with established plaque and gingivitis were used. Following a baseline examination, which involved assessment of plaque, gingivitis, and gingival enlargement, six dogs (test) received nitrendipine twice daily in a high dose, while 3 dogs (control) received placebo. Clinical scorings were repeated after 10 and 20 weeks. At termination of the study gingival biopsies were excised and examined morphometrically. Already at the 10-week examination definite changes in gingival size had occurred, and following 20 weeks of nitrendipine treatment the gingival enlargement had markedly increased. In none of the control dogs were there any signs of gingival size changes. The histopathological examination showed that the only principal changes in histopathological morphology were that areas of non-infiltrated connective tissue in test specimens showed an increase in vascularity and appeared more loose compared with the dense tissue in control specimens. The morphometric analysis demonstrated minor differences between test and control specimens in regard to all tissue fractions observed; however, such differences were numerically very small, and were not considered biologically significant. Thus, the results demonstrated that nitrendipine administered to Beagle dogs during a 20-week period causes marked overgrowth of gingival tissue of apparently normal composition. The fact that cases of gingival overgrowth have been reported among patients receiving other dihydropyridines suggest that the observed gingival overgrowth is an effect of this class of drugs.

Histologic characteristics of clinically healthy gingiva in adolescents.

Gingival biopsies from healthy buccal gingival units in 10 young individuals (12-14 yr) were analyzed morphometrically. The connective tissue was generally characterized by a dense collagenous network, apart from a well defined zone subjacent to the smooth and noninfiltrated junctional epithelium. This zone, which constituted on average 10% of the connective tissue volume, was less dense than the remaining part of the connective tissue and devoid of well defined collagen fiber bundles. This zone could also harbor clusters of inflammatory cells, mainly mononuclear cells, surrounded by non-infiltrated collagen-poor connective tissue. In the noninfiltrated collagen-dense mid-portion of the gingival connective tissue small areas of infiltrates could be found, the composition of which resembled that of the infiltrated areas subjacent to the junctional epithelium.

Effect of listerine on dental plaque and gingivitis.

The present study was performed in 10 adults in order to evaluate the effect of an antiseptic mouthrinse (Listerine) on the rate of dental plaque formation and gingivitis development during a 2-week period when all efforts towards active mechanical oral hygiene were withdrawn. The study was performed as a crossover study and was carried out during four consecutive 2-week periods. During the first and third periods (preparatory periods) the participants were subjected to repeated professional tooth cleanings in order to establish plaque- and gingivitis-free dentitions. During the second and fourth periods (test and control periods) the participants were not allowed to brush their teeth but rinsed their mouths three times a day with Listerine or a placebo mouthwash. Plaque Index, Gingival Index, gingival fluid flow, and crevicular leukocytes were assessed on d 0, 2, 4, 7, and 14. On d 7 and 14, dental plaque was removed from the right and left jaws respectively and the wet weights determined. The chemotactic activity elaborated by the plaques was studied in Boyden chambers. During the Listerine test period, significantly lower Plaque and Gingival Index values were scored and lower amounts of plaque could be sampled in comparison to the control period.