WARNING: Crowns may be bad for the health of (posterior) teeth

The perceived wisdom, when Trevor was a boy at dental school, was that, if a cusp broke, or fell off, a posterior tooth, the correct treatment was to take a 556 diamond bur in a turbine handpiece and prepare the tooth for a gold crown. Indeed, a respected textbook of the time suggested this, advising the placement of a crown if and when ‘teeth are so carious that they cannot be restored with amalgam or a gold inlay’ or, by inference, if a cusp was lost.¹ The concept of minimally invasive dentistry had yet to dawn! However, results in recent publications,^2,3 on the survival of crowned posterior teeth, have challenged this concept: indeed, they confirm how wrong the concept was.

I confess to some bias, because I was co-author, along with Dr Steve Lucarotti, of a series of papers analysing a dataset⁴ consisting of General Dental Services' 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 consisted of items obtained from the payment claims submitted by GDS dentists to the Dental Practice Board (DPB) in Eastbourne, Sussex, UK. The sheer size of the dataset, amounting to over 10 million restorations followed for 16 years, allowed not only analysis of how long restorations last, but also how long the restored tooth survived, which arguably is the more important benchmark. One paper⁵ examined the key findings from nine publications with regard to recorded intervals between placing a restoration in any tooth and re-intervention on the tooth, and time to extraction of the restored tooth, while a further two studies examined the time to extraction of restored molar teeth and survival of crowns and crowned teeth in general.^2,3