Table 1 The basic information of the two groups

Age

37(28, 50)

33(27, 42)

<0.001

Sex (female)

242(60.3%)

297(65.0%)

0.161

Tooth with apical periodontitis

146(36.4%)

106(23.1%)

<0.001

Type of tooth

Anterior tooth and premolar

165(41.1%)

242(52.8%)

0.001

Molar

236(58.9%)

216(47.2%)

0.001

Root canal retreatment

95(23.7%)

49(10.7%)

<0.001

Number of appointments

2.3 ± 0.6

2.9 ± 0.9

P = 0.002

Using operating microscope during root canal preparation

396(98.8%)

207(45.2%)

<0.001

Using operating microscope during root canal obturation

397(99.0%)

239(52.2%)

<0.001