Objectives The aim of this study was to investigate the use of dental amalgam and amalgam alternate materials in primary dental care in Wales. Methods Following pre-piloting, a questionnaire was distributed to 667 dentists registered as working in primary dental care in Wales. The questionnaire sought to determine the current use of amalgam, and amalgam alternative materials in primary dental care services in Wales. In addition, the questionnaire sought to determine the attitudes and confidence of dentists in respect of placement of resin composites as alternatives to dental amalgam. Results A response rate of 40.4% was achieved (n = 270). High levels of reported confidence were seen in relation to placing resin composites in posterior teeth, but these levels reduced as the complexity of the cavity increased (while 82% of respondents 'strongly agreed' that they felt confident in placing resin composites in occlusal cavities, this reduced to 52.6% for three-surface occlusoproximal cavities). Patterns of care suggested that 73.3% of respondents often, or always, place amalgam restorations for NHS-funded dentistry in adults, where two or more posterior restorations are required. This proportion drops to 27% for the same scenario in children, and 19.4% in privately-funded care for adults. Sixty-seven percent of respondents reported that restoring posterior teeth with resin composite is too expensive for NHS-funded dentistry. A similar proportion of respondents (65.9%) agreed, or strongly agreed, that having to place resin composite routinely in posterior teeth would cause appointment delays. Respondents estimated that it would take them 1.61 times as long on average to place a resin composite, compared to an amalgam, in a moderately deep two-surface proximal-occlusal cavity in a lower first permanent molar. Respondents felt that the NHS fees would have to increase by 55-60% to support the restoration of posterior teeth with resin composite, rather than dental amalgam. Conclusions This study provided insight into current practising arrangements of primary dental care practitioners in relation to the use of dental amalgam and resin composites in the restoration of posterior teeth. Based on a sample of mainly UK-trained dentists, it would seem that amalgam remains the material typically selected for restoring posterior teeth in adults for NHS-funded care. While dentists are knowledgeable and embracing of new techniques for posterior resin composite placement, funding arrangements in NHS dentistry appear to be a barrier to the increasing use of resin composite-based, minimum intervention approaches to the restoration of posterior teeth.