Multi-center comparative evaluation of subgingivally delivered sanguinarine and doxycycline in the treatment of periodontitis. I. Study design, procedures, and management.

The design and conduct of a 9-month multi-center clinical trial to evaluate the safety and efficacy of subgingivally delivered 5% sanguinarium chloride (SC) and 10% doxycycline hyclate (DH) from a biodegradable drug delivery system in the treatment of adult periodontitis is described. The 3-group randomized study of 180 adults with moderate to severe periodontitis was a modified double-blind parallel design. One group received DH, one group received SC, and the other group received the vehicle control (VC). Patients selected had two quadrants with a minimum of four periodontal pockets > or = 5 mm in depth with two sites > or = 7 mm. All qualifying sites exhibited bleeding on gentle probing. Qualifying sites were treated at baseline and again at 4 months. Clinical response was assessed by measuring attachment level, probing depth, and bleeding on probing at monthly examinations at qualifying sites and the entire dentition. The plaque index was measured monthly to verify oral hygiene status. The parallel design afforded the opportunity to distinguish between treatment effectiveness of SC, DH, and VC independent of possible crossover effects. Also the effectiveness of oral hygiene in untreated sites of the mouth could be evaluated. Finally, treatment effects in moderate (5 to 6 mm) and deep (> or = 7 mm) pockets in both treated and untreated sites could be compared. The design was capable of simulating a periodontal practice maintenance program and assessing the response according to maintenance and treatment history. Study management procedures that emphasized center examiner and therapist training and adherence to protocol and procedures to reduce variability are described.