RADIOGRAPHIC AND CLINICAL-RESPONSES TO PERIODONTAL THERAPY

MECHANICAL PERIODONTAL THERAPY IS WIDELY USED for a variety of periodo ntal conditions. While the clinical efficacy of this treatment has bee n validated, the radiographic response has not been studied in depth. The purpose of the present study was to examine the clinical and radio graphic response to mechanical periodontal therapy, and assess the fac tors associated with these changes. One hundred and eight patients, wi th established periodontitis, received oral hygiene instruction and me chanical periodontal therapy for a period of 4 to 5 weeks. Scheduled m aintenance visits were performed at 3, 6, 9, and 15 months. Probing de pth (PD) and attachment level (AL) measurements were performed at base line, and at 3 and 15 months. Intraoral radiographs were taken at base line and 12 to 15 months postsurgery using a Rinn alignment system. Al veolar crestal height (ACH) measurements were performed on a pair of d igitized images of the previously taken radiographs. An overall mean o f patients' changes for PD, AL, and ACH was initially computed. Active sites (gainers and losers) were determined using a threshold method, and expressed as patient's percentage of active sites (number of activ e sites of the total sites measured in each patient). Mean overall pro bing reduction and AL gain was 0.5 mm and 0.44 mm, respectively. Of al l sites measured, 16.6% exhibited AL gain, while only 6.2% of all site s exhibited AL loss. Mean overall change in ACH was -0.07 mm, of which 11.8% of all sites exhibited ACH gain, while 15.1% exhibited loss bey ond the threshold. Non-smokers presented no change in bone loss, while smokers continued to lose bone at an annual rate of 0.17 mm. despite treatment (P <0.005). Likewise, the average percent of sites per patie nts showing attachment gain beyond the threshold were much greater in non-smokers (13.9%) compared to 9.0% in smokers (P <0.01). Mean probin g reduction was 50% greater among non-smokers (0.6 mm) when compared t o smokers (0.4 mm), which was also statistically significant (P <0.05) . A positive and significant correlation was established between the p ercentage of sites with AL gain and sites with ACH gain (Rho = 0.40; P = 0.0001). It is suggested that monitoring sites for AL and ACH gain expressed as changes beyond a selective threshold is an important outc ome variable in treatment studies.