Guided tissue regeneration in smokers: effect of aggressive anti-infective therapy in Class II furcation defects

Guided tissue regeneration (GTR) using membrane barriers is still the reconstructive treatment of choice for a variety of periodontal defects. Smokers, however, present a reduced regenerative response to GTR. The purpose of the present study was to design and examine a new protocol with emphasis on anti-infective therapy for patients who are cigarette smokers and who require GTR procedures for the treatment of Class II furcation defects.

Chronic periodontitis patients who were smokers and who exhibited mandibular Class II furcations were initially pooled for further assessment. Patients were randomly assigned to either the experimental group (EG) or a control group (CG). Clinical measurements and indices were recorded at baseline and at 6, 9, and 12 months, and included: plaque assessment index; gingival assessment index; probing depth; and probing attachment level (vertical [PAL-V] and horizontal [PAL-H]) using a prefabricated acrylic stent as a reproducible reference point. All patients underwent hygienic phase periodontal therapy. Next, GTR was performed, and the furcation dimensions (height, width, and depth) were measured. A membrane was placed, and a 25% metronidazole gel was then applied over the outer surface of the membrane (EG only) and the flaps repositioned so that the membrane was completely submerged. Instructions included twice daily rinses with chlorhexidine gluconate 0.2% for 1 week (CG) or as long as the membrane was in place (EG), doxycycline 100 mg x 1/day for 1 week (CG) or 6 to 8 weeks (EG), and ibuprofen 3 x 400 mg/day for 7 days. Patients were initially seen for prophylaxis weekly (EG) or biweekly (CG). Metronidazole was applied to the free gingival margins and/or over the exposed membrane at every prophylactic visit (EG). Six to 8 weeks after surgery, the membrane was removed surgically, and the amount of new tissue growth (NTG) from the cemento-enamel junction (CEJ) to the most coronal extension of the new tissue was recorded. Following membrane retrieval, patients were seen for prophylaxis and oral hygiene reinforcement every month (EG) or quarterly (CG). At 12 months postoperatively, the area was surgically reentered and the surgical measurements repeated.

Thirty-eight subjects, 21 females and 17 males, aged 35 to 61 were accepted in this study. Baseline clinical parameters were similar for both groups. One year postoperatively, there was no statistically significant difference in probing depth reduction or in horizontal PAL between EG and CG, but vertical PAL gain was significantly greater in EG. As for alveolar parameters 1 year postoperatively, the mid CEJ-crest distance and furcation width decreased in EG but increased in CG. A similar trend was observed for furcation height. Furcation depth reduction in both groups was similar. A comparison between new tissue growth at retrieval and eventual bone formation 1 year postoperatively demonstrated a smaller change in EG patients compared to CG patients, which was statistically significant for both the distal and the mid-tooth area, as well as for the tooth mean.

While smoking prevented tissue maturation and mineralization, the anti-infective protocol enhanced these processes, resulting in a more favorable outcome. It is therefore suggested that when GTR is performed for Class II furcation defects in smokers, anti-infective therapy should be incorporated into the treatment protocol to enhance the regenerative outcome in these patients.