A posterior crown fracture due to acute trauma is an uncommon type of dental injury. This case report presents combined endodontic-bioadhesive treatment of a complicated crown fracture of a permanent molar due to a horse riding accident. Endodontic therapy was initiated following surgical removal of the fractured mesiolingual cusp, which was stored frozen until bonding procedures could be carried out. Subgingival and proximal contours of the missing cusp were maintained by an interim glass-ionomer restoration during endodontic therapy. Following root-canal obturation, the fractured cusp was reattached using a total-etch adhesive and composite resin system. The patient was recalled at 1, 3, 6 and 12 months, demonstrating excellent clinical and radiographic findings.