Skip to main content

Table 1 Summary of characteristics of the included studies

From: Influence of heritability on occlusal traits: a systematic review of studies in twins

Authors, year Country Study design Type of twin zygosity and n, mean age (years) Analysis of zygosities Analysis to estimate heritability Clinical records Occlusal and dentoalveolar traits Main outcomes results
Kučević et al. 2017 [19] Serbia Cross-sectional study 30 MZ pairs , 20–40 years NR Correlation coefficient NR 1. PAR index The mean difference between the twins groups were not significant, indicating hereditary dominance for the occlusal characteristics of PAR
Sidlauskas et al. 2016 [20] Lithuania Cross-sectional study 90 MZ pairs, 22.4 years
51 DZ pairs, 20.4 years
DNA analysis Model-fitting approach Cephalometric landmarks 1. Overjet
2. Overbite
Overjet is determined by unique (50%) and shared (50%) environment factors, whereas overbite is determined by dominant genetic factors (76%) and specific environment factors (24%)
Švalkauskienė et al. 2015 [10] Lithuania Cross-sectional study 40 MZ pairs, 17.8 years
32 DZ pairs, 20.2 years
DNA analysis h2 Dental casts 1. Arch length
2. Arch width
Moderate to high h2 coefficients were found for the arch width. In the maxilla, the largest genetic effect was between the lateral incisors. Similar, but lower estimates were found for canines and first premolars in the maxilla, as well as for the first premolars of mandibular arch.
The maxillary arch length is more likely to be genetically determined than mandibular length (h2 = 1 and 0.57, respectively)
Kawala et al. 2007 [13] Poland Cross-sectional study 90 MZ pairs, NR
74 DZ pairs, NR
Serologic and morphologic analysis h2 NR 1. Overjet
2. Overbite
3. Posterior crossbite
4. Type of Angle malocclusion
5. Intertooth spacing
6. Crowding
Hereditary coefficient had low or negative values. Only class II angle malocclusion (11%) and mandibular crowding (12%) showed examined values higher than 10% of hereditary determination
Eguchi et al.
2004 [7]
Australia Cross sectional study 44 MZ pairs, 15.8 years
34 DZ pairs, 17 years
DNA analysis Model-fitting approach and h2 3D dental casts 1. Arches length
2. Arches width
High genetic contribution was found for maxillary and mandibular arch width (ranged from 0.49 to 0.92) and arch length (0.86 mandibular arch and 0.94 for maxillary arch). The width between the lower second premolars showed greater environmental component (51%)
Richards et al. 1990 [21] Australia Cross-sectional study 29 MZ pairs, 15.8 years
19 DZ pairs, 15.8 years
NR h2 Photographs obtained by dental casts 1. Arch morphology
2. Arch asymmetry
The genetic factors influence the shape of the maxillary (h2 = 0.90 and h2 = 0.42 for quartic and quadratic arch terms, respectively) and mandibular (h2 = 0.35 and h2 = 0.0 for quartic and quadratic arch terms, respectively) arches. However, no evidence of genetic factors influence asymmetry in either maxilla or mandible
Boraas et al. 1988 [22] USA Cross-sectional study 32 MZ pairs, 39.9 years
16 DZ pairs, 42.1 years
Serologic analysis Correlation coefficient and h2 Dental cast 1. Overjet
2. Overbite
3. Arch width
4. Crowding
Intercanine and intermolar arch width, and malalignment showed significant resemblance within both monozygotic (p < 0.001) and dizygotic (p < 0.01, p < 0.05) pairs, whereas overjet and overbite showed no significant resemblance within pairs
Sharma et al. 1986 [23] India Cross-sectional study 23 MZ pairs, 17.5 years
35 DZ pairs, 17.5 years
Serological analysis h2 Dental casts 1. Overjet
2. Overbite
3. Posterior crossbite
4. Arch length
5. Arch width
6. Sagittal molar relationship
7. Intertooth spacing
8. Anterior crowding
9. Posterior crowding
10. Total crowding
The occlusal traits: overbite (h2 = 0.77), sagittal molar relationship (h2 = 0.63), anterior (h2 = 0.81) and total teeth crowding (h2 = 0.68), maxillary and mandibular arch length (h2 = 0.72 and 0.66, respectively) and width (h2 = 0.63 and 0.67, respectively) are under potential dominant genetic influence
Potter et al.
1981 [24]
USA Cross-sectional study 87 MZ pairs, 14 years
77 DZ pairs, 14 years
Genetic markers in the blood analysis h2 Dental casts 1. Overjet
2. Overbite
3. Posterior crossbite
4. Sagittal relation of molar
5. Intertooth spacing
6. Crowding
Only overbite and spacing showed significant genetic determination. The other variables had the environmental factors as determinants, but environmental variance is not supported by the occlusal characteristics
Corruccini et al. 1980 [17] USA Cross-sectional study 32 MZ pairs, 14.5 years
28 DZ pairs, 14.5 years
Serologic and dermatoglyphic analysis h2 Dental casts 1. Overjet
2. Overbite
3. Posterior crossbite
4. Arch length
5. Arch asymmetry
6. Arch width
7. Sagittal molar relationship
8. Intertooth spacing
9. Anterior crowding,
10. posterior crowding
11. Total crowding
Maxillary and mandibular arch length (42% and 28%, respectively), upper and lower molar width (16% and 22%, respectively), posterior crossbite (100%), maxillary and mandibular posterior malalignment (95% and 61%), and mandibular anterior malalignment (35%) yield significant heritability estimates
  1. h2 coefficient of heretability, MZ monozygotic twins, DZ dizygotic twins, PAR Peer Assessment Rating, USA United States of America