Table 10.

Summary of apical anatomy results in the mandibular first molar

Studies	Sample size	Apical features
		MAF- Apex	MAF- ApC	AF NO	ApC dimensions
Wolf et al. [57]	118			Number of accessory apical foramen only Frequency mean % MB ML DB DL 0 75.4% 72.0% 76.3% 96.6% 1 19.5% 21.2% 13.6% 3.4% 2 3.4% 5.1% 7.6% 3 0.8% 1.7% 1.7% 4 0.8% 0.8%
Versiani et al. [22]	25 MR with middle mesial canal	Range from 0.2 to 2.4 mm in MMCs		Brazil            Turky 1 3 (10.0%)   7 (38.9%) 2 10 (33.3%) 6 (33.3%) 3 16 (53.4)    5 (27.8%) 4 1 (3.3%)           __
Wolf et al. [61]	118		Average MR = 0.95 mm DR = 1.05 mm		In MR, wide and narrow ApC width 0.24 and 0.30 mm and 0.39 and 0.46 mm in DR
Moe et al. [60]	75			in MB 1–6 (1.55 ± 0.84) in ML 1–4 (1.59 ± 0.86) in isthmus 0–3 (0.41 ± 0.70) in MMC 0–2 (0.23 ± 0.58) IN TOTAL 2–8 (3.78 ± 1.36)	In MR, the largest and smallest ApC width at o.5 mm from the AF was 0.38 and 0.24, respectively
Keles & Keskin [63]	106	Average MB = 0.70 ± 0.51 ML = 0.52 ± 0.50 MMC = 1.34 ± 1.15 Whole MR = 0.85 mm
Asijavičienė et al. [66]	60	Average MR = 1.014 mm DR = 1.089 mm All roots = 1.047 mm		MR DR 1 81.48% 96.67% 2 16.67% 3.33% 3 1.85% ___
Keles et al. [24]	Bifid MR (30) Non bifid MR (30)	In both bifid and non-bifid, this distance ranged from 0—2 mm in MB 0—2.5 mm in ML		Bifid Non bifid 2 16.7% 20% 3 33.3% 46.64% 4 10% 20% 5 20% 6.7% 6 16.7% 3.33% 7 3.3% 3.33%

MAF- Apex Distance between major apical foramen and anatomical apex, MAF- ApC Distance between major and apical constriction (minor apical foramen), MC Mesial canals, DC Distal canal