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The aim of this paper is to provide a review of the current understanding of the mechanisms, cell and factors required for regeneration and restoration of periodontal tissue around natural teeth. Periodontal regeneration is a complex multifactorial process involving cell populations: periodontal ligament cells, bone cells, gingival fibroblasts and epithelial cells. This paper describes bone graft, guided tissue regeneration and enamel matrix derivative with the application of growth factors.

This study describes the distribution of fibronectin and laminin in periodontal tissue of rats after a flap operation. After full thickness flaps were raised, the roots were surgically exposed and planed. Animals were sacrificed at 12 hours, and 1, 3, 5, 7, 14, 28 and 56 days after the wounding. The block specimens were fixed in formalin, decalcified with EDTA, made into serial paraffin sections, and examined after hematoxylin and eosin staining, after Masson-trichrome staining and by indirect immunofluorescence for the presence of fibronectin and laminin. After the wounding, fibronectin was detected in the fibrin clot, and the migratory epithelial cells crossed over this fibrin clot (12 hours-5 days). Fibronectin was deposited heavily in the granulation tissue. When the gingival connective tissue had matured, fibronectin diminished (5-14 days). On the root surface, a layer of fibronectin was present in the region where connective tissue fibers were oriented parallel to the root surface, while no fibronectin was seen at the site of reattachment of the regenerated collagen bundle (14-56 days). Laminin was present in the basement membrane of normal epithelium and blood vessels, but was absent from the internal basal lamina. After the wounding, laminin was absent from the basement membrane zone of the distal site of the migrating epithelium (1-3 days). Upon completion of wound reepithelialization at 5-7 days after wounding, laminin reappeared throughout the basement membrane except the internal basal lamina. These results suggest that fibronectin may be important in the regeneration of epithelium, connective tissue and connective tissue attachment during repair by functioning as an extracellular provisional matrix for migrating cells. On the other hand laminin may be important in maintaining the normal epithelium.

In 8 patients with periodontal diseases under good supragingival plaque control, 22 test teeth each having a pocket not more than 4 mm deep were treated respectively with 3 consecutive administrations of tetracycline immobilized cross-linked collagen film (TC film) at intervals of 1 week, with onceroot planing and with both of these. The therapeutic effects were compared both clinically and micro biologically. The results revealed improvements in clinical symptoms such as reduction in the depth of the pocket, bleeding on pocket probing and the like for each treatment group in 6-12 weeks. The second and third groups also showed remarked gingival recession. Further more, the density of intrapocket microorganisms showed a remarked decrease up to the 8th week for each treatment group and the population of spirochetes showed a decrease up to the 6th week for the first treatment group and up to the 8th-12th week for the second and third treatment group. The results show that both local application of the TC film and root planing are effective in periodontal treatment, but not the combined treatment.

An intimate relationship between the inflammatory state of the gingiva and the amount of gingival crevicular fluid (GCF) is well known. For the measurement of the volume of GCF, filter paper has been used in the past. In the present study, an electrostatic capacity measuring apparatus with sensor that is insertable into gingival sulcus was fabricated. Capacitance of GCF was measured in patients with periodontitis and the following results were obtained. 1. The measuring apparatus was controlled by a personal computer to obtain the data every 0.1 second. As the GI increased at the site of measurement, higher values were obtained, with longer persistence of the trend of increase in the measured value. 2. In view of the stability of the measured values, the amount of GCF appeared to be best expressed as the value obtained after 10 seconds. 3. The correlation between the capacitance and the clinical findings was evaluated at 500 sites. The correlation was the highest in GI followed by P1I, GBI and PD, suggesting the utility of this method in the detection of initial gingival inflammation.