The Effect of Different Lining Strategies on Amalgam Restorations

Patients attending one of eight, United Kingdom general dental practitioners for a new restoration in a posterior tooth will be recruited and informed consent obtained. Each dentist will place 20 amalgam restorations either unlined (control), or lined with calcium hydroxide cement, rmgi cement, or sealed with a resin bonding agent (total - 640).

Pre-operative radiographs and pulp testing will be performed and measurement of cavity size to assess the remaining dental thickness. The pulp status and symptoms will be recorded at 6, 12, and 24 months. Post-operative sensitivity will be recorded by the patient at 1, 3, 7, 14 and 28 days using a visual analogue scale and diary. The dentists will be trained and calibrated to use United States Public Health Service criteria and the condition of the restoration will be assessed at 12 and 24 months.

For each lining option, one product and one admixed amalgam will be provided for use by all the dentists. Training and instruction will be given on the application of the liners and on amalgam condensation to increase standardisation.

The collected data will be assessed to identify any association between the outcome variables and the pre-treatment tooth condition or lining material used using logistic regression (α=0.05).