AIM: To model the inequalities in availability of National Health Service general dental practitioners in England and Wales in relation to key socio-demographic factors. METHODS: Current estimates of the numbers of NHS general dental practitioners for each health authority were related to data from the 1991 census using Poisson regression models, and generalised estimating equations to allow for correlation between results for neighbouring health authorities. RESULTS: An 'average' health authority, without a dental school, would be expected to have 2,138 residents for every NHS dentist. Controlling for relevant factors, health authorities with higher proportions of the following are associated with lower (better) population to dentist ratios by the amounts shown: each 1% higher female population (-11.8%; 95%CI -19.1%, -3.9% P = 0.004); each 1% greater South Asian population (-1.4%; 95%CI -2.1%, -0.7% P <0.001). A health authority with a dental school is associated with a more favourable ratio compared with one without such a facility (-9.2%; 95%CI -16.2%, -1.6% P = 0.019). Each additional 1% of the following are associated with a worse ratio by the amounts shown: children aged 0 to 14 years old (+5.2%; 95% CI +2.4%, +8.1% P < 0.001); adults aged over 65 years old (+2.8%, 95%CI +1.0%, +4.7% P =0.002); households without a car (+0.8%; 95%CI 0.0%, +1.6% P =0.042). CONCLUSIONS: Ensuring access to dental care may be a more complex issue than simply providing adequate numbers of dentists at a national level. Any manpower planning exercise should additionally consider local factors that may act as incentives or disincentives to those professionals who provide care.