Periodontal research using nationwide registry data

Abstract

The present doctoral project used registry-based data to address clinically relevant research questions in the field of periodontology. Study I utilised information from a single registry to investigate the impact of furcation involvement on molar loss. Based on longitudinal data from 381,450 individuals, deep furcation involvement (degree II-III) was confirmed as a strong risk factor for molar loss. However, the decline in molar survival following detection of deep furcation involvement was relatively small (8% after 10 years). Studies II and III combined data from seven different registers to evaluate associations between diabetes (type 1 and type 2), periodontitis, tooth loss and peri-implantitis. Study II included 28,801 individuals with type 1 diabetes, 251,645 with type 2 diabetes and 597,644 matched controls without diabetes. Individuals with type 1 diabetes and poor glycaemic control were at higher risk of periodontitis and tooth loss, whereas the risk was not elevated among those maintaining good glycaemic control when compared to individuals without diabetes. In contrast, individuals with type 2 diabetes were at higher risk irrespective of glycaemic control, with the association being strongest among those with poor control. Periodontitis was associated with a significant but modest increase in the risk of diabetes-related microvascular complications (retinopathy and nephropathy). Study III included a subgroup of the above population with dental implants (18,975 and 2,030 individuals for evaluations of prevalence and incidence of peri-implantitis, respectively). Both diabetes types were associated with an increased risk of peri-implantitis and implant loss, with glycaemic control emerging again as a key factor in the relationship. These associations persisted after adjustment for periodontitis, suggesting an independent link between diabetes and peri-implantitis. Study IV investigated the association between diabetes and complete edentulism and explored the modifying effects of socioeconomic factors. Registry-based data on 506,336 Swedish individuals and registry and survey data on 50,980 Danish individuals were utilised. Type 1 and type 2 diabetes were associated with a higher prevalence of edentulism in both populations. Socioeconomic disadvantage (reflected by lower income and shorter education) further amplified this risk. Overall, this series of studies demonstrates that registry-based research in periodontology can generate population-level evidence that may inform policy, support resource allocation and contribute to hypothesis generation for future mechanistic and interventional research.