Ericsson, I, Lindhe, J. Recession in sites with inadequate width of the keratinized gingiva. J. Clin. Perio. 11:96, 1984

AIM

The present study sought to investigate the inflammatory response in the gingival units with wide or narrow zones of keratinized gingiva subsequent to the placement of restorations with subgingivally located margins.

MATERIALS AND METHODS

Three 1 year old beagles were used. Clinical and radiographic examinations were performed. Though the entire study the dogs were fed a diet which facilitated gross accumulation of plaque and calculus. Cotton ligatures were placed around the necks of the mandibular 3rd and 4th premolars, they were replaced to the receding gingival margin every month for 6 mos. When 40-50% of the supporting tissues had been lost in the experimental periodontitis, they were removed and the dogs were allowed to accumulate deposits for another 60 days. The inflamed periodontal tissue was excised using either an apical reposition flap or a GV (keratinized tissue removed)procedure. Both procedures contained Sc/RP and sutures. For the next 4 months, the maintenance period consisted of 2 weeks of 0.2% CHX thereafter mechanical plaque control twice daily.

RESULTS

• On day 0 notches were placed in the buccal surface at the gingival margin. Steel bands of thickness of 0.1 mm were placed on the buccal of the premolars at a level 1 mm apical to the notch with cement. The dogs were allowed a to accumulate plaque and calculus for 6 months. After the 6 mos. ,a clinical exam was performed in order to access the position of the steel bands in relation to the notch and the marginal gingiva, the presence of subgingival plaque ,and the condition of he gingiva. The animals were sacrificed.
• All experimental sites, parts of the steel bands were still in a subgingival position. In 8 of 12 of the GV group and none of the flap group had the gingival margin shifted apically in comparison with day 0.
• Histometric ,the distance from gingival margin to the junctional epithelium for the flap was 1.544 mm and the GV was 1.29 mm, not significant.
• The distance from the junctional epithelium to the bony crest was approximately 0.60 mm for both groups.
• The distance from the notch to the gingival margin for the flap was 0.470 mm and for the GV, 0.745 mm, this was significant.
• For infiltrated connective tissue expressed in % of the total free gingival unit, was significant, flap - 57.2%, anf GV - 28.1%

Conclusions

• Restorations in a subgingival position in the gingival sites allow plaque to accumulate and establish conditions which promote the development of mod-sev. gingivitis. In the experimental site, it was characterized by the presence of inadequate width of keratinized gingiva, the inflammatory reactions were almost always accompanied by a loss of gingival tissue. GV group 0.745 mm. This indicates recession.
• This suggests that in gingival sites with narrow, in contrast to sites with a wide zone of keratinized gingiva, subgingiva plaque formation in the presence of subgingival restoration may result in recession of the gingival margin.
• In this study a narrow zone of keratinized gingiva harbored an inflammatory cell infiltrate which occupied the major portion of the connective tissue of the free gingiva. While in the wide zone of keratinized gingiva, the inflammation was confined to the tooth side of the free gingiva.
• Any osseous performed, experimental periodontitis, no control, restoration with overhang of 0.1 mm
• The recession was less than a 1 mm, in 6 months. interesting would longer duration.

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