The aim of endodontic therapy is the prevention or treatment of apical periodontitis. Some years ago, 2 endodontic classification systems, the Dutch Endodontic Treatment Index (DETI) and the Endodontic Treatment Classification (ETC), were introduced in the Netherlands. These systems differentiate between complicated and uncomplicated endodontic cases. Before treatment, the systems may help in assessing the difficulties and risks of performing an endodontic treatment and in deciding whether to carry out treatment or refer the patient to an endodontist. Root canal therapy may involve considerable risks. This is illustrated with three clinical cases, which show the sort of complications that may be prevented using the 2 classification systems.

Complaints concerning restorative treatments at disciplinary tribunals are relatively rare. The nature of the complaints, the judgements, and the implicit view on caries management are, however, a cause of concern. Usually, the complaints are on alleged negligence because lesions were not or were too late restored. Modern caries management concentrating on disease control rather than on damage repair and its minimally invasive nature could be reasons of complaints concerning perceived negligence. As usual, careful documentation of findings, diagnostics, risk assessment, and monitoring decisions and good patient communication are decisive in preventing complaints. However, post-graduate education of dentists in caries detection, diagnosis, and management is needed to reduce the variability of caries care provided.

Complications and failures are unavoidable in dentoalveolar surgery, but can be reduced if treatment is carried out in the proper manner. Yet, one has to accept a certain percentage of complications and failures and the patient should be informed about that prior to surgery. Complications become reproachable when insufficient diagnostic procedures have been carried out or when surgery has not been performed in the proper fashion. Insufficient prior information, even in cases of referral, must be seen as reproachable practice, especially in the context of the Law on Medical Treatment Agreement.

Risks of orthodontic treatment identified in the literature are: enamel damage, root resorption, periodontal damage, temporomandibular disorders, tooth devitalization, treatment failure, and relapse. Enamel damage in the form of irreversible demineralization can take place during treatment with fixed appliances in the absence of adequate oral hygiene. Root resorption occurs, but seldom to the point of clinical relevance. Individual susceptibility and genetics are determining factors. Periodontal damage occurs as gingival recessions. Temporomandibular disorders and tooth devitalization hardly occur. Treatment failure is related to the assessed pre-treatment goals and dependent on the knowledge and skills of the care provider, patient-cooperation, and factors beyond anyone’s control. Relapse is a common feature, but does not constitute a treatment risk. The greatest risk is a failure to adequately inform the patient concerning all of the (im)possibilities and their consequences.

New haematopoietic stem cell transplantation procedures make the treatment available to patients who previously did not qualify, such as the elderly. In addition, the spectrum of oral complications associated with haematopoietic stem cell transplantation has altered as a result of the recent developments. This article is a review of the main principles of haematopoietic stem cell transplantation and provides information on oral complications which may develop, such as mucositis, infections, bleeding, graft-versus-host disease, xerostomia, hyposalivation, altered taste, secondary tumors, osteoporosis, osteonecrosis and growing and developing disturbancies. Finally, the role of dental care providers in cases of haematopoietic stem cell transplantation is addressed.