The periodontal tissue is sensitive to any any subgingival irregularities, such the subgingival margins of prosthetic restorations. In this clinical-statistical study, we analysed and evaluated the periodontal damages which appear at the level of subgingival prosthetic restorations, appreciated by the periodontal change in colour, volume, bleeding on probing, probing the depth of the periodontal pocket, gingival retraction. This study compared also the degree of the periodontal disease related by age, sex, smokers/non-smokers, other general diseases. Proper oral hygiene and a good fit of the prosthetic restoration at the finish line of the preparation are the main criteria to maintain periodontal health. Some of the general diseases (cardiovascular diseases, diabetes) are correlated with periodontal health, they can negatively influence the evolution periodontitis. Inadequate subgingival marginal of restoration (invasion of biological space, large, overcontured), favours the accumulation of dental plaque and encouraging development of subgingival plaque. The periodontal inflammatory processes are aggravates by the various general pathologies, smoking, poor oral hygiene regardless of the type of the subgingival finish line.