Does the use of antimicrobials in different periodontal treatment strategies result in better treatment outcomes? - A radiographic analysis.

Design: The paper by Kubberød et al. is a single-centre, double-blinded, prospective randomised control trial, comparing the radiographic alveolar bone levels in patients with periodontal disease following different treatment protocols over a 5-year period. In total, 184 patient were recruited to the study, and 161 (87.5%) of the patients returned for follow up over a 5-year period. The patients underwent a 3-month, pre-treatment oral hygiene phase before being randomised to one of 4 treatment regimens: (i) same day full mouth disinfection + adjunctive metronidazole; (ii) same day full mouth disinfection + placebo; (iii) scaling and root planing + adjunctive metronidazole; (iv) scaling and root planing + placebo. Scaling and root planing was carried out over a period of 2 to 4 weeks. The participants were enroled in maintenance treatment at 3, 6 and 12 months, then bi-annually for 5 years following active treatment. Radiographic recordings were taken at baseline pre-treatment and then at the 5-year follow up examination. Clinical periodontal measurements such as plaque/bleeding scores, and PPD/CAL (in mm) were also recorded pre/post-treatment.

Case Selection: Participants for this study were recruited over 2 years from referrals to a specialist periodontal clinic in Norway. The patients were aged between 35-75 and at the time of inclusion into the trial, had no systemic conditions relevant to periodontitis. The participants underwent a 3-month pre-treatment oral hygiene phase to attempt to reduce the risk of false pocketing at the initial baseline measurements. For inclusion into the trial, participants were required to have more than 5 persistent sites of PPD > 5 mm, and < 15% plaque sites following the pre-treatment hygiene regime. Participants were also only eligible if there were no known reactions to metronidazole or known to carry microorganisms resistant to metronidazole.

Data Analysis: Bland-Altman plots were used to allow for assessment of the reproducibility of the radiographic measurement carried out for the examiner assessing the radiographs. Linear regression was used to describe the degree of bone loss noted over the 5-year period.

Results: Firstly, the authors describe the radiographic examiners results from the Bland-Altman plots, which shows the examiner to have an error range of -0.04 to 0.01 mm in 95% of cases with the error intervals (-0.47,0.40), (-0.60,0.54) and (-0.55,0.56). Secondly, the authors present the number of periodontal pocket sites (interproximal) examined at the base and at the 5-year follow up. The average number of sites with readings for RBL, CAL and PPD at base line averaged from 41.2 and 43.7 depending on the treatment arm. This was lower at the 5-year follow up, between 30.2 and 36.9. The number of sites with no data (indicating loss of tooth) also increased from baseline to the 5-year follow up, from 4 to 13. Lastly, the results show the change in RBL, CAL and PPD from baseline to 5-year follow up, post-treatment for all 4 treatment protocols. This shows that metronidazole in conjunction with mechanical debridement has a small but statistically insignificant positive effect on RBL and CAL gain. Full mouth disinfection was found to result in less reduction in PPD compared with scaling and root planing; however, this was also found to be statistically insignificant.

Conclusions: Regardless of the treatment protocol, all patients demonstrated a reduction in PPD. The FDIS+MTZ group had no statistically significant change in the RBL. However, the other treatment regimens showed overall bone loss over the 5-year period, which again is statistically unimportant. Overall, the authors conclude that resolution of periodontitis induced inflammation is better observed through clinical measurements of the soft tissues, such as PPD and CAL, versus radiographic examination. This was particularly evident as the discrepancies between RBL and CAL were largest for shallower PPDs.