Background: Structured quality management is an important aspect for improving patient dental care outcomes, but reliable evidence to validate effects is lacking. We aimed to examine the effectiveness of a quality management program in primary dental care settings in Germany.Methods: This was an exploratory study with a before-after-design. 45 dental care practices that had completed the European Practice Assessment (EPA) accreditation scheme twice (intervention group) were selected for the study. The mean interval between the before and after assessment was 36 months. The comparison group comprised of 56 dental practices that had undergone their first assessment simultaneously with follow-up assessment in the intervention group. Aggregated scores for five EPA domains: 'infrastructure', 'information', 'finance', 'quality and safety' and 'people' were calculated.Results: In the intervention group, small non-significant improvements were found in the EPA domains. At follow-up, the intervention group had higher scores on EPA domains as compared with the comparison group (range of differences was 4.2 to 10.8 across domains). These differences were all significant in regression analyses, which controlled for relevant dental practice characteristics.Conclusions: Dental care practices that implemented a quality management program had better organizational quality in contrast to a comparison group. This may reflect both improvements in the intervention group and a selection effect of dental practices volunteering for the first round of EPA practice assessment.