This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

(1) To evaluate the clinical outcome of primary teeth restored with PMCs compared with those restored with conventional filling materials such as amalgam, composite, glass ionomer, resin modified glass ionomer, compomers.
(2) To determine whether the extent of decay has an effect on the clinical outcome of primary teeth restored with PMCs compared with those restored with conventional filling materials.
(3) To report any adverse effects associated with PMCs or conventional fillings such as periodontal (gum) problems, temporomandibular disorders (TMD), phobia as a result of undergoing restorative treatment, alteration in age at exfoliation. We recognise that these side effects may not be well reported in studies where an assessment of efficacy is the main outcome.

The following null hypothesis will be tested:
There is no difference in the clinical outcome of primary molar teeth restored with PMCs when compared to those where conventional fillings have been placed.