Table 2 Characteristics of the included studies in the systematic review

1

Paknahad et al. 2022 [24]

Iran

15–25 years; (21.28 ± 2.47 yrs)

200 CBCT images of 200 subjects; 100 females and 100 males

Linear

New Tom VGi; scan

time, 8.9 seconds; 5 mA; 19 mAs; 120 kV; coronal slices reconstructed with a slice thickness of 0.3

and a slice interval of 1 mm

The roof, floor, height of the pulp chamber, mesial and distal enamel thickness, dentin thickness at the height of contour and crown length

Maxillary and mandibular first molar teeth

Yes

Overall 80.5% accuracy in sex estimation when first molars were used.

2

Bansal et al. 2022 [7]

India

20–65 years

60 CBCT images of 60 subjects;

29 females and 31 males

Linear

Sirona digital imaging system with 70–74 kV, 10 mA, and 10.8 s, with a field of view (FOV) 8 cm × 8 cm, and voxel size of

160 μm [3]; sliced into three dimensions; sagittal, coronal and axial sections of central incisor

Pulp-to-tooth area ratio

Maxillary canines and central incisors

No

Not stated

3

Warnecki et al. 2022 [29]

Poland

17–35 years

92 CBCT images of 92 subjects;43 females & 49 males

Linear

Carestream CS 8200 CS 3D, Carestream Health, Rochester, NY, USA; length of each tooth was measured separately in the sagittal section with 3D Slicer

Lateral skull radiograph; SNA, SNB and ANB angles; presence (or absence) of asymmetry in facial features; a shift of the chin greater than 5 mm relative to the facial midline; length of each tooth

Single rooted and multi-rooted teeth

Yes

Not stated

4

Yagci et al. 2021 [28]

Turkey

20.88 ± 2.48 years

560 CBCT images of 101 subjects;57 females and 44 males

Linear

NewTom 5G, QR, (Verona, Italy); scanning time 14–18 seconds; collimation height 13 cm; exposure time 3.6 seconds; and voxel sizes were 50 μm)

Enamel thickness; proximal areas of maxillary and mandibular incisors, canines, and premolars.

Maxillary and mandibular incisors, canines and premolars

Yes

Not stated

5

Esmaeilyfard et al. 2021 [23]

Iran

15–25 years; Mean age of 21.28 ± 2.47 years

485 CBCT images of 485 subjects;240 females and 245 males

Linear

New Tom VGi; scan time 8.9 s, 5 mA, 19 mAs, 120 kV; corrected sagittal and coronal slices were reconstructed with a slice thickness of 0.3 and a slice interval of 1 mm

Roof, floor, and height of the pulp chamber, enamel and dentin thickness at the height of contour, tooth width, crown length in both buccolingual and mesiodistal aspects

Permanent first molars

Yes

Average classification accuracy was 92.31%.

6

De Koninck et al. 2021 [30]

Portugal

18–60 years

58 CBCT of 58 subjects; 27 females and 31 males

Linear

ProMax 3D Plus device (Planmeca, Finland); voxel size of 0.2 mm and 0.15 mm and the same energy parameters

(90 kV and 10 mA)

Maximum buccolingual dimension of the cervical root measured in the midsagittal plane

Mandibular canine

Yes

79% accuracy in estimating the sex.

7

Denny et al. 2021 [8]

India

15–30 years

100 CBCT images of 100 subjects; 56 females and 44 males

Linear +Volumetric

Promax 3D, Mid version (Planmeca Oy., Helsinki, Finland)

Height of the crown, height of the coronal pulp cavity, tooth – coronal index

Four mandibular molars

No

Not stated

8

Fauzi 2021 [21]

India

No Mention

100 CBCT images of 100 subjects; 56 females and 44 males

Linear

CBCT

Mesiodistal width

Mandibular central incisor

Yes

Not stated

9

Fardim et al. 2021 [3]

Brazil

20–65 years

1190 CBCT image of 1190 subjects;606 females and 584 males

Volumetric

I-CAT Next Generation

(Imaging Sciences International, HA, PA, EUA); voxel of 0.25

mm; Axial, coronal and sagittal image slices.

Pulp chamber volume

Mandibular canines, pre-molars and molars

Yes

Not stated

10

Topbas and Okkesim 2021 [27]

Turkey

12–69 years

332 CBCT images of 332 subjects; 162 females and 170 males

Volumetric

Planmeca 3D Mid (Planmeca, Helsinki, Finland) device with a voxel size of 200 μm and using 85 kVp, 10 mAs and 14 s scanning time; field of view was 15 × 9 cm.; voxel size: a 0.2 mm³

Pulp volume, tooth volume

Maxillary or mandibular molar tooth

Yes

76.6% in estimating female sex and 56.3% accuracy in estimating male sex.

11

Salam et al., 2021 [9]

Eygpt

18–25 years

100 CBCT images of 100 subjects; 50 females and 50 males

Linear

Planmeca, Promax 3D Max, Finland; all scans were output with 512 X 512 pixels per slice and 8 bits per pixel; voxel size: 0.16 mm³.

Crown width and height, enamel thickness, arch depth, and width.

Mandibular permanent canines and first molars

Yes

Not stated

12

Issrani et al. 2020 [5]

Saudi Arabia

17–35 years

400 CBCT images of 100 subjects; Equal males and females

Volumetric

3D CBCT

Mesio-distal width; inter-canine distance; Mandibular canine index

Mandibular canines

No

47.8% accuracy in estimating sex.

13

Shalakizadeh et al., 2020 [25]

Iran

20–50 years

133 CBCT of 266 subjects; 156 females and 110 males

Linear

Newtom VGi

CBCT unit (Verona, Italy). 1536 × 1920 pixels, a pixel size of 127 × 127, a pixel depth of 14 bits, a rotation

of 360 degrees, a scan time of 18 s and a kVp of 110; slice thickness of 1 mm at 0.25 mm intervals

Mean length of canine teeth

Maxillary and mandibular canine

Yes

Not stated

14

Manhaes-Caldas et al. 2019 [19]

Brazil

8–36 years

128 CBCT images of 128 subjects; 64 females and 64 males

Volumetric

Picasso Trio unit (Vatech, Hwaseong, South Korea), adjusted at 80 kVp, 3.7 mA and a voxel size of 0.2 mm; 3D Slicer software, version 4.8 (sagittal and coronal reconstruction).

Total volume of the dental crown; Image-based volumetric assessment by manual segmentation

Upper central incisors, upper and lower canines, and lower lateral incisors

Yes

83.7% accuracy in estimating sex.

15

Alam et al. 2019 [4]

Saudi Arabia

20–45 years

252 CBCT Images;252 subjects; 93 females and 159 males

Linear + Volumetric

3D CBCT

Tooth size from 2nd molar to 2nd molar of maxillary and mandibular arch

Full dentition (except 3rd molars)

No

Not stated

16

Andrade et al. 2019 [2]

Brazil

13–70 years

116 CBCT images of 116 subjects sample were homogenous in terms of age and sex; total of 232 teeth

Volumetric

Kodak K9500R scanner (Carestream

Health, Rochester, RY); voxel size of 0.2 mm³ and 0.3 mm3 and the same energy parameters (90 kVp

and 10 mA); field of view (15 × 9 cm and 20 × 18 cm).

Pulp volumes

Upper central incisors and canines

Yes

High accuracy of sex estimation

17

Rahman and Ramakrishnan 2019 [22]

India

18–40 years

50 CBCT images of 50 subjects;25 females and 25 males

Linear

CBCT

Mesio-distal width at apical third, middle third, and cervical third region.

Maxillary central incisors

Yes

Not stated

18

Kavas and Tumen 2019 [26]

Turkey

7–18 years

80 CBCT images of 80 subjects; 40 females & 40 males; 160 M

Volumetric

i-CAT (Imaging Sciences International, Hatfield, PA, USA); voxel size: 0,3 mm; 3D Slicer

Pulp chamber volume

Mandibular and maxillary first molars

Yes

Not stated

19

Marchenko et al. 2017 [31]

Ukraine

Adolescents

77 CBCT images of 77 subjects; 42 females and 35 males; mesocephalic boys - 16, boys brachycephalic – 19, mesocephalic girls – 16, brachycephalic girls– 26

Linear

Veraviewepocs 3D, Morita (Japan); 3D image - cylinder 8x8cm - thickness 0,2/0,125 mm, dose of radiation 0,11–0,48 mSv, voltage and amperage 60-90 kV/2-10 mA

Vestibular-oral and mesio-distal projection length of the root; Length of roots of incisors and canines of the upper and lower jaw

Upper and lower Incisors and canines

Yes

Not stated

20

De Angelis et al. 2015 [32]

Italy

15–83 years

87 CBCT images of 87 subjects; 46 females and 41males

Volumetric

i-Cat Next Generation (Imaging Sciences

International, Hatfield, Pa); voxel size: 0.4 mm; scan time: 8.9 s; scan width: 23.2 cm; scan height: 17 cm

Dental volume; mean dental volume, minimum dental volume; maximum dental volume mean pulp chamber volume, minimum pulp chamber volume; maximum pulp chamber volume; mean percentage ratio between pulp chamber and tooth.

Upper Canines

Yes

Overall 80.5% accuracy in estimating the sex.

21

Porto et al.2015 [20]

Brazil

22–70 years

72 CBCT images of 118 subjects; 60 females and 58 males

Volumetric

i-CAT® Next

Generation (Cone Beam 3-D Dental Imaging System e Imaging

Sciences International, Hat!eld, PA/USA); (voxel-size) of 0.25 mm; stores only the axial images

Pulp cavity volume, hard tissue volume, tooth volume and pulp cavity/tooth volume ratio

Upper central incisors

No

Not stated

22

Llena et al. 2014 [33]

Spain

Mean age of 45.26 years

70 CBCT images of 70 subjects;31 females and 39 males;126 premolars

Linear

Kodak 9000 3D unit (Carestream

Dental, Atlanta, GA, USA); 70 kV, 10 mA, and 10.8 s; μm; voxel size: 76 μm

Tooth position in the arch, number of roots, length of the tooth and root, number of canals, canal system configuration; Distance from the cemento-enamel junction to the canal bifurcation and canal reunification, number of foramina, root curvature, angle location, and distance of the angle vertex to the apex

Lower premolars

Yes

Not stated

23

Alam et al. 2014 [6] Malaysia

16–35 years

53 CBCT images of 53 subjects; 21 females and 32 males

Linear

Plameca Promax 3D

(Helsinki, Finland); transaxial and sagittal slices (1 mm)

Tooth size, arch length, arch perimeter, inter-canine, inter-first premolar, inter-second premolar and inter-molar widths

Incisors, canines, premolars, 1st molar; arch length & arch perimeter

Yes

Not stated