The INCENTIVE study: a mixed-methods evaluation of an innovation in commissioning and delivery of primary dental care compared with traditional dental contracting

Background Over the past decade, commissioning of primary care dentistry has seen contract currency evolving from payment for units of dental activity (UDAs) towards blended contracts that include key performance indicators such as access, quality and improved health outcome. Objectives The aim of this study was to evaluate a blended/incentive-driven model of dental service provision. To (1) explore stakeholder perspectives of the new service delivery model; (2) assess the effectiveness of the new service delivery model in reducing the risk of and amount of dental disease and enhancing oral health-related quality of life (OHQoL) in patients; and (3) assess cost-effectiveness of the new service delivery model. Methods Using a mixed-methods approach, the study included three dental practices working under the blended/incentive-driven (incentive) contract and three working under the UDAs (traditional) contract. All were based in West Yorkshire. The qualitative study reports on the meaning of key aspects of the model for three stakeholder groups [lay people (patients and individuals without a dentist), commissioners and the primary care dental teams], with framework analysis of focus group and semistructured interview data. A non-randomised study compared clinical effectiveness and cost-effectiveness of treatment under the two contracts. The primary outcome was gingivitis, measured using bleeding on probing. Secondary outcomes included OHQoL and cost-effectiveness. Results Participants in the qualitative study associated the incentive contract with more access, greater use of skill mix and improved health outcomes. In the quantitative analyses, of 550 participants recruited, 291 attended baseline and follow-up. Given missing data and following quality assurance, 188 were included in the bleeding on probing analysis, 187 in the caries assessment and 210 in the economic analysis. The results were mixed. The primary outcome favoured the incentive practices, whereas the assessment of caries favoured the traditional practices. Incentive practices attracted a higher cost for the service commissioner, but were financially attractive for the dental provider at the practice level. Differences in generic health-related quality of life were negligible. Positive changes over time in OHQoL in both groups were statistically significant. Limitations The results of the quantitative analysis should be treated with caution given small sample numbers, reservations about the validity of pooling, differential dropout results and data quality issues. Conclusions A large proportion of people in this study who had access to a dentist did not follow up on oral care. These individuals are more likely to be younger males and have poorer oral health. Although access to dental services was increased, this did not appear to facilitate continued use of services. Future work Further research is required to understand how best to promote and encourage appropriate dental service attendance, especially among those with a high level of need, to avoid increasing health inequalities, and to assess the financial impact of the contract. For dental practitioners, there are challenges around perceptions about preventative dentistry and use of the risk assessments and care pathways. Changes in skill mix pose further challenges. Funding The National Institute for Health Research Health Services and Delivery Research programme.