Effect of Postsurgical Systemic Doxycycline After Regenerative Periodontal Therapy

Study Hypothesis: The administration of 200 mg doxycycline once a day for 7 days after regenerative periodontal therapy of infrabony defects improves the results of therapy (clinical vertical attachment gains \[CAL-V\], bony fill) and reduces postoperative flap dehiscence and defect exposure. In each of 90 patients one infrabony defect shall be treated by regenerative techniques (guided tissue regeneration \[GTR\], enamel matrix derivative \[EMD\]). Prior to , 6, 12, and 24 months after surgery clinical measurements (Plaque Index \[PlI\], probing depth \[PD\], vertical clinical attachment level \[CAL-V\], Gingival Index \[GI\]) and standardized radiographs are obtained.