Table 3.

Results from simple and multivariable logistic regression analyses of extraction answers depending on dentist-related and tooth-related factors (p < .05)

Variable	n	%	Crude ORa (95% CI)	P value	Adjusted ORb (95% CI)	P value
Dentist-related factors
Gender
Female	347	9.9	Ref.
Male	955	9.5	1.0 (0.8–1.1)	0.496	1.1 (1.0–1.3)	0.111
Years of experience
< 5	309	8.0	Ref.
6–15	287	8.6	1.1 (0.9–1.3)	0.330	1.4 (1.1–1.7)	0.000
16–25	143	6.1	0.8 (0.6–0.9)	0.007	1.1 (0.8–1.3)	0.805
> 25	563	14.0	1.9 (1.6–2.2)	0.000	2.2 (2.0–2.6)	0.000
Professional registration
General dental practitioners	798	13.0	Ref.
Endodontists	155	11.4	0.9 (0.7–1.0)	0.110	0.9 (0.7–1.0)	0.141
Oral surgeons	22	1.2	0.1 (0.1–0.1)	0.000	0.1 (0.0–0.1)	0.000
Prosthodontists	137	10.6	0.8 (0.7–1.0)	0.017	0.8 (0.6–0.9)	0.006
Periodontists	81	7.3	0.5 (0.4–0.7)	0.000	0.5 (0.4–0.7)	0.000
Othersc	109	5.8	0.4 (0.3–0.5)	0.000	0.4 (0.3–0.5)	0.000
Tooth-related factors
Tooth position
Incisor	373	8.2	Ref.
Premolar	352	7.8	0.9 (0.8–1.1)	0.431	0.9 (0.8–1.1)	0.405
Molar	577	12.8	1.6 (1.4–1.9)	0.000	1.7 (1.5–2.0)	0.000
Coronal status
Cavity	671	9.9	Ref.
Full veneer crown	631	9.3	0.9 (0.8–1.0)	0.205	0.9 (0.8–1.0)	0.206
Root canal filling status
Absent	499	7.3	Ref.
Underfilling	803	11.9	1.7 (1.5–1.9)	0.000	1.8 (1.6–2.0)	0.000
Size of periapical radiolucency
Small	107	2.4	Ref.
Medium	290	6.4	2.8 (2.2–3.5)	0.000	2.8 (2.2–3.5)	0.000
Large	905	19.9	10.1 (8.3–12.4)	0.000	10.4 (8.5–12.8)	0.000

Abbreviations: CI Confidence interval, OR Odds ratio, Ref. Reference category

^aCrude OR is the odds ratio resulted from simple logistic regression analysis; ^b Adjusted OR is the odds ratio resulted from multivariable logistic regression analysis

^cOthers include pedodontists, orthodontitsts, oral pathologists and oral medicine specialists