Treatment with fixed appliances in adolescents may transitionally increase the values of all periodontal indices and stimulate the growth of periodontopathogenic bacteria, but without destructive effects on deep periodontal tissues.

The therapy with fixed appliances may transitionally increase the growth of periodontopathogenic bacteria and consequently result in gingival inflammatory response but without destructive effect on deep periodontal tissues.

Indices of oral hygiene level and periodontal status (dental plaque index, gingival index and periodontal pockets' depth) were significantly worsened in patients with diabetes. Negative influence on remained teeth had patients' age (> 50 years), duration of diabetes (> 20 years) and bad oral hygiene. About half of the patients had a total or partial bridge suggesting that periodontitis is significant complication of diabetes mellitus.