"The study's demonstration of a strong association between cannabis use and periodontitis experience by age 32 years indicates that long-term smoking of cannabis is detrimental to the periodontal tissues and that public health measures to reduce the prevalence of cannabis smoking may have periodontal benefits for the population."
"Cannabis Smoking and Periodontal Disease Among Young Adults," Journal of the American Medical Association, Feb. 6, 2008

• Professor, Dental Epidemiology and Public Health, Sir John Walsh Research Institute
• Editor, New Zealand Dental Journal

• PhD, University of Adelaide, 1999
• MComDent (Master of Community Dentistry), University of Otago, 1991
• MA, University of Leeds, 1986
• BDS (Bachelor of Dental Surgery), University of Otago, 1981
• BSc, school unknown

• Cowritten with Richie Poulton, Jonathan M. Broadbent, Terrie E. Moffitt, Avshalom Caspi, James D. Beck, David Welch, and Robert J. Hancox, "Cannabis Smoking and Periodontal Disease Among Young Adults," published in the Journal of the American Medical Association, Feb. 6, 2001
• Cowritten with R. Hashim and A.R.C. Pack, "Smoking in Adolescence as a Predictor of Early Loss of Periodontal Attachment," Community Dentistry and Oral Epidemiology, 2001
• Cowritten with R. Hashim and A.R.C. Pack, "The Prevalence and Intra-oral Distribution of Periodontal Loss of Attachment in a Birth Cohort of 26-year-Olds," Journal of Periodontology, 2000
• Cowritten with R. Poulton, E. Kruger and D.M. Boyd DM, "Socio-economic and Behavioural Risk Factors for Tooth Loss from Age 18 to 26 Among Participants in the Dunedin Multidisciplinary Health and Development Study," Caries Research, 2000
• Cowritten with D. Locker, "Dental Neglect and Dental Health Among 26-year-olds in the Dunedin Multidisciplinary Health and Development Study," Community Dentistry and Oral Epidemiology, 2000