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. 2009 Dec;54(Suppl 1):S45–S51. doi: 10.1016/j.archoralbio.2008.06.009

Table 1.

Contribution of genetic and environmental components to variation in selected dental features in Australian twins.

Dental trait Best-fitting model h2 95% CI
Tooth emergence (i1) AE 94 91–96



Intercuspal distances (M1)
 MB–DB AE 60 29–78
 DB–DL AE 65 49–77
 DL–ML E – –
 ML–MB CE – –



Crown diameters (I1)
 MD AE 88 –
 LL AE 80 –



Crown diameters (C)
 MD ADE 86a –
 LL AE 85 –



Crown diameters (M1)
 MD ACE 59 46–69
 BL ACE 61 51–71



Carabelli trait AE 90 –



Arch dimensions
 Breadth AE 82 61–91
 Depth AE 92 81–97



Occlusal traits
 Overbite AE 53 28–71
 Overjet AE 28 2–50

i1: primary mandibular central incisor; M1: permanent maxillary first molar; I1: permanent maxillary central incisor; C: permanent maxillary canine; MB: mesiobuccal; DB: distobuccal; DL: distolingual; ML: mesiolingual; MD: mesiodistal; LL: labiolingual; BL: buccolingual; A: additive genetic variance; D: non-additive genetic variance; C: common environmental variance; E: unique environmental variance; h2: narrow-sense heritability (additive genetic variance), 95% CI = 95% confidence interval reported when available.

a

broad-sense heritability (additive plus non-additive genetic variance).