The ultimate guide to restoration longevity in England and Wales. Part 10: key findings from a ten million...

This paper defines key points from a ten million restoration dataset in order to compare and contrast the data from the previous nine papers, identifying common themes and/or differences in the factors affecting the survival of restored teeth to next intervention or extraction.

It is the aim of this paper to present data on the survival of restorations in teeth by analysis of the time to re-intervention on the restorations and time to extraction of the restored tooth, and to discuss key findings regarding this.

A data set was established, consisting of General Dental Services (GDS) patients, this being obtained from all records for adults (aged 18 or over at date of acceptance) in the GDS of England and Wales between 1990 and 2006. The data consist of items obtained from the payment claims submitted by GDS dentists to the Dental Practice Board (DPB) in Eastbourne, Sussex, UK. This study examined the key findings with regard to recorded intervals between placing a restoration in any tooth and re-intervention on the tooth, with the size of the dataset also permitting examination of the time to extraction of the restored tooth.

Data for more than three million different patients and more than 25 million courses of treatment were included in the analysis. Included were all records for adults (aged 18 or over at date of acceptance). Overall, 13,896,048 tooth restorations were included in the analysis. With regard to time to re-intervention, overall, between 32% and 42% of restorations, depending on tooth type, had survived at 15 years, and with regard to time to extraction of the restored tooth, the range was from 77.8% to 84.2%.

The analysis confirms that larger restorations of all types and in all types of teeth generally performed less well than smaller restorations. Crowns perform better in time to re-intervention than direct restorations, but worse, particularly for younger patients, in time to extraction. Patient treatment history, measured as the average annual spend on treatment, is a major factor in the survival of restored teeth, both to re-intervention and to extraction. The greater the spend, the worse the survival. Regarding dentists, there is little difference in the survival of restorations placed by dentists of different gender, but dentists' age has been shown to play a part in the present investigation, with restorations placed by younger dentists performing better for all types of restoration except crowns. For direct restorations, the older the patient the poorer the survival of the restoration, whether to re-intervention or to extraction. The prognosis of a tooth which receives a root filling in the same course of treatment as the other restoration is much poorer than for teeth without such a root filling.