Table 2. Subgroup analysis to investigate differences between studies included in meta-analysis for failure rate.

Analyses	Subgroup	Number of studies	RR [95% CI]	P value	I2 (%)	P value for heterogeneity
Overall		14	2.09 [1.18, 3.69]	0.01	0%	0.63
Sample size (implant)	≤50	7	1.98 [0.68, 5.73]	0.21	40%	0.19
	>50	7	2.13 [1.08, 4.19]	0.03	0%	0.82
Time of publication	Before 2007	8	2.57 [1.11, 5.94]	0.03	0%	0.52
	After 2007	6	1.72 [0.78, 3.78]	0.18	0%	0.39
Definition of early	1 week	4	1.00 [0.17, 5.77]	1.00	/	/
	3 weeks	4	2.60 [1.17, 5.79]	0.02	0%	0.87
	6 weeks	4	2.72 [0.69, 10.77]	0.15	62%	0.11
Definition of conventional	≤3 months	8	2.78 [1.07, 7.22]	0.04	24%	0.27
	>3 months	5	1.93 [0.86, 4.33]	0.11	0%	0.64
Extent of restoration	Full-arch	12	2.37 [1.28, 4.39]	0.006	0%	0.62
	Single	2	0.72 [0.12, 4.22]	0.72	0%	0.46
Position of implants	Maxilla	2	1.22 [0.33, 4.58]	0.77	0%	0.96
	Mandibular	11	2.67 [1.36, 5.24]	0.004	0%	0.58
Type of restoration	Fixed	6	1.91 [1.00, 3.64]	0.05	0%	0.66
	Removable	8	2.86 [0.83, 9.86]	0.10	50%	0.16