Introduction: Since the loss of one's own teeth decreases with age, the various effects of various wear and tear on tooth structure and their therapy have become increasingly important. Erosive and abrasive/attritive processes may overlap. Attritive processes can also progress more rapidly in erosively damaged teeth. If the erosive loss of hard tooth substance particularly affects the palatal and occlusal surfaces of the maxillary teeth, an endogenous aetiology in the sense of chronic gastrointestinal disturbances or regular vomiting with bulimia nervosa can be assumed. However, buccal defects in the lower jaw due to the nocturnal lying position allow reflux diseases to be distinguished from chronic vomiting. Bulimia nervosa has a gender ratio of 1:20 (m:f) and a prevalence of 0.5-5% in western industrial countries. Frequently, affected patients practice intensified mechanical oral hygiene, which leads to increased loss of tooth substance. If erosive and mechanical wear occur simultaneously, a temporally linear correlation can no longer be assumed. Case report: In the case presented, the patient describes a pronounced nocturnal bruxism (abrasion/attrition) and long-term bulimia nervosa. The functional symptoms of the patient (severe head- and earaches) support the dental findings regarding bruxism. Bulimia patients usually show erosions in the area of the oral and occlusal tooth surfaces, especially the incisors. At the time of initial presentation, the patient had already suffered for years from aesthetic, functional, and phonetic limitations. Due to restorations with crowns and bridges in the posterior region, the vertical dimension was largely retained. Teeth 12-22 showed a clinical coronal residual height of approx. 3 mm. Since all 4 anterior teeth still showed vitality, it had to be considered whether they should be devitalised for the forthcoming prosthetic restoration. Since root-canal-treated teeth are more susceptible to fractures than vital teeth, this should be avoided wherever possible. The front of the upper jaw was clearly visible, especially when laughing (gummy smile). Although there was no increased loss of vertical dimension, there was not enough intermaxillary space in the anterior region to reconstruct the anterior teeth. To avoid devitalisation and to harmonise the gingival margin, a crown extension was performed. The required slight bite elevation was achieved by crowning all posterior maxillary teeth that had previously been treated with insufficient restorations. A functional wax-up was created. A Michigan splint with a modelled maxillary front served as a therapeutic denture for 6 months. Then a surgical crown extension was performed with special consideration for the harmonisation of the gingival margin. A mock-up was used as a template and later as a temporary. The patient showed no symptoms after 6 months and was fitted with full zircon crowns in the maxilla. Discussion: Since the loss of hard tooth substance was already at an advanced stage, extensive restoration work had to be carried out. The patient was fitted with a Michigan splint to protect the restorations from attritive secondary damage. In the therapy or prevention of non-carious tooth substance defects, the patient's personal responsibility for success must be made clear. Keywords: erosion, bulimia nervosa, prosthetic rehabilitation