AIM: To study the reasons for and outcome of malpractice claims handled by the regional and national Danish Dental Complaint Boards (DCB) from 1995 to 2004. Specific attention was paid to endodontic claims. Three hypotheses were explored: endodontic malpractice claims are frequent, they are mostly due to technical shortcomings and male dentists are overrepresented. METHODOLOGY: The reasons for the claims were classified and assigned to at least one of 14 categories. Cases assigned to the 'endodontic treatment' category were further sub-categorized, and reasons for malpractice were examined. An age and gender analysis of dentists and complaining patients was performed only on data obtained from the endodontic cases. RESULTS: Overall, 3611 malpractice claims were registered. In 43% of the cases the dentist was judged to be guilty of malpractice. In the majority of the appealed cases the original verdict was affirmed (62.2%) by the national DCB. After crown & bridge treatment (23%) endodontic treatment was the next frequent malpractice claim (13.7%), in which 'technical complications or incorrect treatment' was the most frequent sub-categorization (28.4%). Reasons for endodontic malpractice verdicts were related to root filling quality, the use of a paraformaldehyde product and instrument fracture. Male dentists were most often involved in an endodontic claim, and the majority of complainants were females. CONCLUSIONS: Endodontic malpractice claims were relatively common in Denmark. Perceived technical shortcomings dominated the patients' complaints concerning root canal treatment. Male dentists and female patients were overrepresented indicating a gender influence on aspects of the doctor-patient communication important for liability claims.