The clinical and expert evaluation of the unfavourable consequences of the provision of the inadequate dental implantation treatment has demonstrated the ever increasing number of justified complaints and civilian lawsuits instituted annually in connection with the infringements of health associated with the poor quality of the medical care provided to the patients. The authors present the results of commission forensic medical expertise performed on account of the civilian lawsuits instituted by a 74 year-old patient K. against a private stomatological polyclinic. It was shown that the medical personnel of the polyclinic disregarded the objective contraindications for the surgical treatment of the patient on the day of her application for the medical assistance. It is concluded that the advanced age of the patient and well apparent atrophy of the alveolar part of the lower jaw required preliminary substantiation of the necessity of the surgical intervention. However, the diagnostic and treatment errors in the form of incomprehensive examination and the application of the inadequate implantation technique resulted in postoperative complications including severe disturbances of the masticatory function and painful sensations. The commission forensic medical expertise reported in the present article has failed to reveal any objective factors that might have been responsible for the above diagnostic and treatment errors and established the immediate cause-and-effect relationship between them and the resultant unfavourable consequences of the treatment. The opinion of the commission was recognized to be well-substantiated by the court and provided a basis for the judicial judgement in favour of patient K.