Network meta-analysis of studies included in the Clinical Practice Guideline on the nonsurgical treatment of chronic periodontitis

Abstract

Aim: The recent ADA-commissioned Clinical Practice Guideline on the nonsurgical treatment of chronic periodontitis has provided the most exhaustive library of clinical trials on scaling and root planing (SRP) with or without adjuncts. This network meta-analysis (NMA) compared the adjuncts against each other.

Materials and methods: A star-shaped NMA was performed based on 36 indirect comparisons of clinical attachment-level (CAL) gains among nine adjuncts in 74 studies from the Clinical Practice Guideline.

Results: All pairwise differences were accompanied by wide confidence intervals, and none of the adjuncts were statistically significantly superior to another. Local doxycycline hyclate and photodynamic therapy with a diode laser had the highest probabilities for ranking first and second, respectively. Publication bias was evident, with fewer than expected studies with small effects. The lack of these studies inflated the treatment effects by an estimated by 20%.

Conclusions: Adjuncts improve CAL gain by about a third of a mm over 6-12 months compared with SRP alone, but no significant differences were found among the adjuncts. The patient-perceived benefit of this gain is unclear because CAL is a physical measure made by the clinician and not a patient-oriented outcome. Publication bias inflated the observed treatment effects.

Keywords: Periodontal disease; periodontitis.

Figure 1

Network plot of 74 studies in nine adjuncts (plus SRP) versus a common comparator SRP alone included in the Guideline Project (nodes and edges weighed according to the number of studies involved in each comparison of nine adjuncts versus SRP alone)

Figure 2

Treatment rankings. Bar chart (left panel) of the probability for each of 9 adjuvant treatments and SRP alone for being the best to the worst in terms of CAL gain. Plots of the surface under the cumulative ranking curves, SUCRA (right panel) for 9 adjuvant treatments and SRP alone. Larger areas under the curve indicate better treatments. 1= systemic host modulation (sub-antimicrobial dose doxycycline) (SDD); 2= systemic antimicrobials (ANTI); 3= chlorhexidine chips (CHX); 4= doxycycline hyclate gel (DH); 5= minocycline microspheres (MM); 6= photodynamic therapy [PDT] with a diode laser (PDT); 7= diode laser [non-PDT] (DL); 8= Nd: YAG lasers (NDL); 9= Erbium lasers (ERL)

Figure 3

Contour-enhanced funnel plot of the 72 studies (all studies of the Guidelines shown, but without Pradeep and Ginanelli to achieve moderate heterogeneity) plotting each study’s CAL effect versus its standard error as well as “trim and fill” imputed studies