A 15-year-old patient has got a trauma. He complains of mandibular pain getting worse during swallowing, chewing, especially mouth opening. Objectively: face configuration isabnormal, there is a large haematoma in the region of the right mandibular angle. Palpation of this region is painful. The mouth is half open, lower lip frenulum is shifted to the right of the central line. Pressing upon the chin causes pain in the part of mandible on the right. What is the provisional diagnosis?