Effects of immediate and delayed loading protocols on marginal bone loss around implants in unsplinted mandibular implant-retained overdentures: a systematic review and meta-analysis

Table 3 Quality assessment and risk of bias of the included non-randomized studies

Study	Coding manual for cohort studies	Newcastle–Ottawa Scale
Turkyilmaz et al. [51]	Selection
	(1) Representativeness of the exposed cohort	d
	(2) Selection of the non-exposed cohort	a☆
	(3) Ascertainment of exposure	a☆
	(4) Demonstration that outcome of interest was not present at start of study	a☆
	Comparability
	(1) Comparability of cohorts on the basis of the design or analysis	a☆
	Outcome
	(1) Assessment of outcome	a☆
	(2) Was follow-up long enough for outcomes to occur	a☆
	(3) Adequacy of follow up of cohorts	a☆
	Total Scale	☆☆☆☆☆☆☆
De Smet et al. [50]	Selection
	(1) Representativeness of the exposed cohort	d
	(2) Selection of the non-exposed cohort	a☆
	(3) Ascertainment of exposure	a☆
	(4) Demonstration that outcome of interest was not present at start of study	a☆
	Comparability
	(1) Comparability of cohorts on the basis of the design or analysis	a☆
	Outcome
	(1) Assessment of outcome	a☆
	(2) Was follow-up long enough for outcomes to occur	a☆
	(3) Adequacy of follow up of cohorts	b☆
	Total Scale	☆☆☆☆☆☆☆

Selection: (1) d: no description of the derivation of the cohort; (2) a: drawn from the same community as the exposed cohort ☆; (3) a: secure record (e.g., surgical records) ☆; (4) a: yes ☆. Comparability: (1) a: study controls for ____ (select the most important factor) ☆. Outcome: (1) a: independent blind assessment ☆; (2) a: yes (select an adequate follow up period for outcome of interest) ☆; (3) a: complete follow up—all subjects accounted for ☆; b) subjects lost to follow up unlikely to introduce bias—small number lost → ____ % (select an adequate %) follow up, or description provided of those lost) ☆

ISSN: 1472-6831