Table 2. Simple and multiple mixed model analyses in all teeth.

Variables		Simple mixed model			Multiple mixed model
		B estimate	Confidence interval	P value	B estimate	Confidence interval	P value
Sex
	Male (ref.)	0	-	-	0	-	-
	Female	−0.45	−1.73, 0.83	0.4776	−0.59	−1.71, 0.54	0.2919
Age		−0.04	−0.1, 0.02	0.1504	0	−0.06, 0.05	0.8565
Number of extracted teeth
	Single extraction (ref.)	0	-	-	0	-	-
	Multiple extraction	1.01	−0.29, 2.31	0.1233	0.89	−0.28, 2.05	0.1276
Tooth site
	First premolar (ref.)	0	-	-	0	-	-
	Second premolar	−0.27	−2.08, 1.54	0.7615	−1.3	−3.02, 0.42	0.1317
	First molar	−0.84	−2.49, 0.81	0.3052	−1.17	−2.97, 0.63	0.1897
	Second molar	−1.29	−3.23, 0.65	0.1834	−2.35	−4.24, −0.45	0.0177
Reason for extraction
	Periodontal (ref.)	0	-	-	0	-	-
	Endodontic	−0.6	−3.24, 2.04	0.6453	−0.83	−3.21, 1.55	0.4775
	Fracture	0.67	−1.3, 2.64	0.4932	0.8	−0.99, 2.59	0.3652
	Unknown	1.92	−0.84, 4.68	0.1653	3.10	0.7, 5.5	0.0140
Time interval following tooth extraction
	≤6 months (ref.)	0	-	-	0	-	-
	>6 and ≤12 months	1.23	−0.22, 2.68	0.0939	1.02	−0.26, 2.3	0.1110
	>12 months	0.48	−1.15, 2.12	0.5508	−0.04	−1.46, 1.38	0.9588
Relationship between root and sinus floor
	Class I (ref.)	0	-	-	0	-	-
	Class II	0.74	−0.56, 2.04	0.2526	−1.06	−2.42, 0.3	0.1198
	Class III	1.01	−0.55, 2.57	0.1964	−0.69	−2.27, 0.88	0.3704
	Class IV	0.38	−1.89, 2.66	0.7313	−1.23	−3.43, 0.97	0.2588
	Class V	0.39	−1.8, 2.57	0.7191	−1.55	−3.77, 0.67	0.1603
Sinus mucosal thickening
	≤5 mm (ref.)	0	-	-	0	-	-
	>5 and ≤10 mm	−0.47	−2.05, 1.12	0.5540	−0.45	−1.9, 1.0	0.5250
	>10 mm	−2.01	−4.58, 0.56	0.1208	−2.07	−4.3, 0.16	0.0673