Table 2. Meta-regression assessment of the influence of different levels of risk of bias on the treatment effect estimates.

(1): Sequence generation; (2): Allocation concealment; (3) Blinding of outcome assessment; (4) Sequence generation OR Allocation concealment; (5) Sequence generation OR Blinding of outcome assessment; (6) Allocation concealment OR Blinding of outcome assessment; (7) Sequence generation OR Allocation concealment ORBlinding of outcome assessment. NA = not available

Study	Comparison/ Outcome	Risk of bias
		(1)	(2)	(3)	(4)	(5)
Riley and Lamont 2013 (Peridontology)	Plaque at 6 to 7 months vs. Baseline prophylaxis
	(A-1) Quigley-Hein Plaque Index	0.665	0.123	NA	0.123	0.665
	Plaque Severity Index versus Baseline prophylaxis
	(A-2) Plaque Severity Index	NA	NA	NA	NA	NA
	Gingivitis at 6 to 9 month versus. Baseline prophylaxis
	(A-3) Löe-Silness Gingival Index	0.669	0.244	NA	0.244	0.669
	Gingivitis at 6 to 7 month versus Baseline prophylaxis
	(A-4) Gingivitis Severity Index	0.055	0.055	NA	0.055	0.055
Yaacob et al. 2014 (Periodontology)	All powered toothbrushes versus manual toothbrushes
	(A-5) Plaque scores at 1 to 3 months at all sites	0.535	0.405	0.850	0.400	0.535
	Gingival scores at 1 to 3 months at all sites
	(A-6) Loe and Silness	0.846	0.459	0.053	0.457	0.846
	(A-7) Plaque scores at >3 months	0.313	0.371	0.439	0.371	0.313
	Rotation oscillation powered toothbrushes versus manual toothbrushes
	(A-8) Plaque scores at 1 to 3 month at all sites	0.471	0.375	NA	0.375	0.471
	(A-9) Gingival scores at 1 to 3 months at all sites	0.069	0.244	0.029*	0.277	0.069
Esposito et al. 2013 (Implant Dentistry)	Immediate versus conventional loading
	(B-1) Implant failure	0.825	0.893	0.971	0.893	0.881

* p-value<0.05