Facial alveolar bone thickness and modifying factors of anterior maxillary teeth: a systematic review and meta-analysis of cone-beam computed tomography studies

Table 4 Facial alveolar bone thickness using FBC as reference point, with meta-regression of sample geographical setting at CI, LI and C

Tooth type	Reference point	N (teeth number)	Geographical setting	Beta	SE	95% CI	z (p-value)	R²
CI	1 mm	14 (3038)	America (ref.)				0.139	16.00%
			Asia	− 0.06	0.14	− 0.34 0.21	0.645
			Europe	0.15	0.16	− 0.17 0.47	0.369
			Africa	− 0.27	0.18	− 0.63 0.08	0.132
	3 mm	7 (1369)	America (ref.)				0.094	31.30%
			Asia	− 0.08	0.22	− 0.51 0.33	0.682
			Europe	0.37	0.24	− 0.09 0.83	0.118
	5 mm	8 (1654)	America (ref.)				0.037*	40.10%
			Asia	− 0.13	0.15	− 0.42 0.16	0.389
			Europe	0.26	0.17	− 0.08 0.59	0.135
LI	1 mm	13 (1726)	America (ref.)				0.049*	29.30%
			Asia	− 0.14	0.14	− 0.42 0.14	0.322
			Europe	0.16	0.16	− 0.16 0.47	0.336
			Africa	− 0.24	0.17	− 0.59 0.11	0.174
	3 mm	6 (957)	Asia (ref.)				< 0.001***	77.10%
			Europe	0.58	0.16	0.27 0.89	< 0.001***
			America	− 0.17	0.2	− 0.55 0.23	0.419
	5 mm	7 (1336)	Asia (ref.)				0.004**	61.70%
			Europe	0.48	0.16	0.17 0.79	0.002**
			America	− 0.11	0.2	− 0.50 0.28	0.582
C	1 mm	8 (1652)	Asia (ref.)				< 0.001***	87.10%
			Europe	0.09	0.06	− 0.03 0.22	0.128
			America	− 0.44	0.09	− 0.61 − 0.26	< 0.001***
			Africa	− 0.38	0.09	− 0.55 − 0.2	< 0.001***
	3 mm	6 (1006)	Asia (ref.)				0.005**	63.70%
			Europe	0.28	0.17	− 0.06 0.61	0.105
			America	0.21	0.21	− 0.86 − 0.03	0.035*
	5 mm	6 (840)	Asia (ref.)				0.012*	58.70%
			Europe	0.33	0.16	0.01 0.64	0.044*
			America	− 0.28	0.2	− 0.68 0.11	0.159

N study number, SE standard error, CI confidence interval, I² I-squared, QH Cochran´s Q, R² R-squared
^*p < 0.05; **p < 0.01; ***p < 0.001 (Strength of statistical significance)

ISSN: 1472-6831