Title
Reasons for placement and replacement of crowns in primary dental care in Wales.

Lead researcher
Dr Christopher Lynch, School of Dentistry, Cardiff University.


Research question
What are the reasons for placement and replacement of crowns in primary dental care in Wales?

Hypothesis
It will be possible to adequately describe and record the decision-making practices of primary dental care practitioners in relation to the placement and replacement of crowns.

Aims

  1. To describe the reasons for placement and replacement of crowns in primary dental care practices in Wales.
  2.  To collect pilot information on the decision-making process for the replacement of crowns in primary dental care practices in Wales: this will allow preparation of a larger funding application, probably to NIHR-HTA, for a primary-care based randomised controlled trial to compare repair vs. replacement of defective crowns.
  3. To help build a primary dental care research network, which will, in turn, build primary dental care research capacity in Wales.


Background
A crown (sometimes termed a „cap‟) is a dental prosthesis, which is used to cover all of the surfaces of a tooth. It is usually provided for teeth that have fractured, or those which have large fillings and are at risk of fracture. It may also be provided for discoloured teeth, or those that have had root canal (nerve) treatments. A crown is usually made of metal alone, ceramic alone, or a combination of each. A minimum of two clinical visits is usually required: the first where the tooth is shaped to receive a crown („prepared‟) and an impression made of the resulting tooth. This is then sent to a dental laboratory where a technician fabricates a crown. At the second clinical visit, the crown is fitted to the shaped tooth. Fees for crowns vary: under NHS funded dental care in Wales, the fee paid by a patient for one crown is £198 (although the
dentist will receive additional payment as part of the fee structure). Fees for privately-funded crowns vary widely, but can range from £250 - £1,000 per crown. The system of recording the cost of NHS-funded dental care has changed following the implementation of a new dental contract in 2006 meaning it is no longer possible to determine precisely how many crowns are currently provided by the NHS. However in 2005, the NHS spent £117.5M providing crowns in dental practices in England & Wales. This figure does not include the costs of this treatment in secondary and, community care, or privately.


Based on the results of the most recent Adult Dental Health Survey (2009), 37% of adults in the UK with teeth have crowns. Crowns are mainly provided for older patients: almost 59% of those aged 45-74 years have a crown. It is also estimated that of those adults with crowns, each of these adults have, on average, 3 per person, amounting to an estimated 47.6 million crowns across England, Wales and Northern Ireland. Figures from Wales are in keeping with these trends: 37% of adults in Wales had at least one crown, while adults in Wales with crowns had 2.8 crowns on average.
Previous research suggests that between 48% - 68% of crowns provided in NHS funded dentistry are replaced within 10 years (Burke & Lucarotti 2009). This replacement may be due to reasons such as new decay at the crown margin, or mechanical failure. However, it is often based on subjective decisions by the operator. Analysis of data relating to crowns suggests that type of crown, patient age, patient attendance pattern and method of remuneration affect the survival of crowns (Burke & Lucarotti 2009). As such, the potential for over-treatment and subjectivity on the part of operators (i.e. the primary care dental practitioner) is high.

Summary of study design

  1. Work package one is an observational study of the prescribing habits of primary dental care practitioners (both private and NHS) in relation to new and replacement crowns.
  2. Work package two will involve semi-structured telephone interviews with 25 primary dental care practitioners from phase one.
 Total awarded
£12,734