Twin Research and Human Genetics


Genetic, Epigenetic, and Environmental Influences on Dentofacial Structures and Oral Health: Ongoing Studies of Australian Twins and Their Families

Toby Hughesa1, Michelle Bockmanna1, Suzanna Mihailidisa1, Corinna Bennetta1, Abbe Harrisa1, W. Kim Seowa2, Dimitra Lekkasa1, Sarbin Ranjitkara1, Loreta Rupinskasa1, Sandra Pinkertona1, Alan Brooka1a3, Richard Smitha4 and Grant C. Townsenda1 c1

a1 Craniofacial Biology Research Group, School of Dentistry, The University of Adelaide, South Australia, Australia

a2 School of Dentistry, University of Queensland, Brisbane, Australia

a3 Institute of Dentistry, Queen Mary University of London, London, United Kingdom

a4 School of Dental Science, University of Liverpool, United Kingdom


The Craniofacial Biology Research Group in the School of Dentistry at The University of Adelaide is entering an exciting new phase of its studies of dental development and oral health in twins and their families. Studies of the teeth and faces of Australian twins have been continuing for nearly 30 years, with three major cohorts of twins recruited over that time, and currently we are working with twins aged 2 years old to adults. Cross-sectional data and records relating to teeth and faces of twins are available for around 300 pairs of teenage twins, as well as longitudinal data for 300 pairs of twins examined at three different stages of development, once with primary teeth, once at the mixed dentition stage, and then again when the permanent teeth had emerged. The third cohort of twins comprises over 600 pairs of twins recruited at around birth, together with other family members. The emphasis in this third group of twins has been to record the timing of emergence of the primary teeth and also to sample saliva and dental plaque to establish the timing of colonization of decay-forming bacteria in the mouth. Analyses have confirmed that genetic factors strongly influence variation in timing of primary tooth emergence. The research team is now beginning to carry out clinical examinations of the twins to see whether those who become colonized earlier with decay-forming bacteria develop dental decay at an earlier age. By making comparisons within and between monozygotic (MZ) and dizygotic (DZ) twin pairs and applying modern molecular approaches, we are now teasing out how genetic, epigenetic, and environmental factors interact to influence dental development and also oral health.

(Received August 23 2012)

(Accepted September 04 2012)

(Online publication October 12 2012)


  • teeth;
  • faces;
  • twins;
  • dentistry;
  • craniofacial development


c1 address for correspondence: Professor Grant C. Townsend, Craniofacial Biology Research Group, School of Dentistry, The University of Adelaide, South Australia 5005, Australia. E-mail: