Comparison 4. Nanocrystalline hydroxyapatite versus bovine‐derived xenograft and resorbable membrane (4 years).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Recurrence of perimplantitis	1		Risk Ratio (M‐H, Fixed, 95% CI)	Totals not selected
1.1 1 year	1		Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
1.2 2 years	1		Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
1.3 4 years	1		Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
2 Change in attachment levels	1		Mean Difference (IV, Fixed, 95% CI)	Totals not selected
2.1 6 months	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
2.2 1 year	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
2.3 2 years	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
2.4 4 years	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
3 Change in probing pocket depths	1		Mean Difference (IV, Fixed, 95% CI)	Totals not selected
3.1 6 months	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
3.2 1 year	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
3.3 2 years	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
3.4 4 years	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
4 Change in recessions	1		Mean Difference (IV, Fixed, 95% CI)	Totals not selected
4.1 6 months	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
4.2 1 year	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
4.3 2 years	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
4.4 4 years	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]