Objective: To evaluate the effects of tooth loss and age on oral health impacts in two nationally-representative adult populations.

Methods: Frequency of impacts was measured using the 14-item Oral Health Impact Profile (OHIP) in cross-sectional national surveys of representative samples of adults in the United Kingdom (n=5,281) and Australia (n=3,910). OHIP scores were expressed as the sum of ordinal response codes for each item (from 0=Never to 4=Very often). Number of missing teeth was recorded by examiners in the UK and by subject-report in Australia.

Results: Although the countries were significantly different in terms of the mean scores recorded, the patterns with age and tooth retention were similar. There was an “inverted U” relationship between age and OHIP scores in both countries: scores increased from the youngest adults to a plateau maximum between 30 and 70 years (mean, s.e.: UK 5.4, 0.14; Australia 7.9, 0.22) before reducing sharply (mean, s.e.: UK 3.4, 0.07; Australia 6.4, 0.35) and significantly (P<0.01) in older age. OHIP scores reduced as the number teeth increased, but the reduction was generally greatest above a threshold of 20 teeth. This pattern was consistent across all age groups. The interaction between these two factors revealed up to a 7-fold difference in mean scores for different age/tooth count categories. In both countries the lowest scores were for people aged 70+ who had 25+ teeth (mean, s.e.:UK 1.7, 0.67; Australia 3.6, 0.47). The highest scores were in 30-49 year olds; in the UK where there were less than 16 teeth (11.8, 1.66) and in Australia where there were 17-20 teeth (14.9, 2.06).

Conclusion: Number of natural teeth and age are independently associated with the oral health impacts affecting daily life. In all age groups, impacts reduced markedly where the number of teeth exceeded 20.

J.G. Steele, A.E. Sanders*, G.D. Slade, S. Lahti, P.F. Allen, N.M. Nuttall

Presented at the 80th General Session and Exhibition of the IADR, 6-9 March 2002, San Diego, USA