Scaling and root-planing treatment with adjunctive subgingival minocycline. A clinical pilot study over six months, of sites adjacent to and remote from the antibiotic application.

Aim: A clinical trial was performed to determine if a single dose of subgingival minocycline has (i) a clinical spillover effect at adjacent and remote sites and (ii) an adjunctive effect to scaling and root-planing.

Materials And Methods: Each of the 15 adult subjects included in the study had to present with at least two pairs of adjacent 6-9 mm pockets each pair located on adjacent teeth in an interproximal space, on opposite sides of the mouth. Each study site was required to have at least 3 mm loss of attachment. Following a baseline examination including assessments of plaque, pocket depth (PD), clinical attachment levels (CAL) and bleeding on probing (BOP), instruction in oral hygiene was given. Each subject was treated with a single episode of scaling and root-planing (SRP), of approximately 90 minutes duration using ultrasonic and hand instrumentation under local anaesthetic, if indicated. This was followed by a single application of 1 mg of minocycline in the form of Minocycline Periodontal Therapeutic System (MPTS) into one of the four sites selected at random by another clinician, who also randomly selected one of the two sites on the opposite side of the mouth to be designated the Remote site. Clinical re-examinations were performed at 3- and 6-months.

Results: At six months the CAL gains at the MPTS sites were statistically significantly different when compared with the Adjacent sites (P=0.04). The proportion of sites demonstrating a CAL gain (> or = 2 mm) was higher in the MPTS group (73%) compared with the Adjacent (40%) and Remote sites (53%). Periodontal therapy, (MPTS+SRP) and (SRP alone) resulted in a statistically significant reduction in mean pocket depths (P<0.01). However no statistically significant differences in pocket depths were found between treatment groups over the six months of the study. The proportion of sites demonstrating a clinically significant reduction in PD (> or = 2 mm) was higher in the MPTS sites (80%) compared with the Adjacent sites (53%) and Remote sites (53%). BOP was significantly reduced at all sites over the duration of the study except at the Adjacent sites at three months (P<0.05).

Conclusion: No apparent clinical spillover effect of minocycline was demonstrated over the six months of the study. There was a trend for greater improvement in all clinical parameters at the MPTS sites compared with the Adjacent and Remote sites except for plaque scores. This trend needs to be examined in a study with a sufficient number of subjects to allow statistical significance.