Longevity of complete dentures after relines: A 20-year population based retrospective study of 187,227 publicly insured adults

Abstract

To evaluate the incidence of the first complete denture reline in a population of publicly insured adults and to assess its association with complete denture longevity. The records of 187,227 Australian adults who accessed subsidized complete denture treatment through public clinics were assessed. The number of years from denture issue to denture replacement was modelled using Poisson regression. Over 20 years, 5.9% of participants received at least one reline. The incidence rate (IR) for relines was highest in the first year of denture life, (IR: 0.031, 95%CI 0.030 to 0.032) and decreased as dentures increased in age. Dentures receiving an early reline (within 12 months of denture issue) had a mean longevity of 5.03 years (SD: 3.76) and dentures which received a late reline had a mean longevity of 7.12 years (SD: 3.32). Multivariate Poisson regression found that dentures which received an early reline were associated with a 2% reduction in denture longevity in comparison to those who did not receive a reline (IRR: 0.98, 95%CI: 0.97 to 0.99, p<0.001). Dentures which received a late reline were associated with a 15% increase in longevity in comparison to dentures which received no reline (IRR: 1.15, 95%CI: 1.13 to 1.16, p<0.001). The incidence of relining in this population was low. The results show that the timing of a reline during a denture's life modulates its effect on denture longevity. Denture longevity was prolonged in those receiving a late reline and was reduced in those receiving an early reline. Relines performed after at least 12 months of denture issue can be expected to increase the longevity of complete dentures. This effect was not observed for relines performed within the first 12 months of denture provision.