Mandibular Fracture During Mandibular Third Molar Extraction

摘要

Pre-operative planning for the extraction of mandibular third molars is of fundamental importance, particularly in patients over the age of 40 years, in whom osteotomies and odontotomies procedures must be included to prevent mandibular fractures Conservative treatment of the mandibular fracture has advantages and disadvantages, and can present excellent results when well indicated and performed. The main aim of this article is to relate a case of fracture of the mandibular angle in a 40-year old patient, as a result of third molar extraction on the right side. The patient had two fracture lines favourable to reduction, reported feeling a difference in dental occlusion and was treated with intermaxillary fixation with an Erich bar for 45 days. The follow-up shows complete bone consolidation of the fracture traces after four years. Authors contributed equally. Introduction Surgeries for third molar extractions are common procedures in dental offices and are the most frequent procedures in oral surgery. 1 The prophylactic removal of third molars is based on the concept of minimizing future risks of disease and surgical morbidity in older patients; this concept is questionable. 2,3,4 There are various indications for extraction, such as: prevention of pericoronaritis, this being the most frequent indication; prevention of caries in the third molar or in the distal region of the second molar; prevention of second molar root reabsorption; prevention of odontogenic cyst and tumour formation; and prevention of mandibular fractures. 5,6,7,8,9 Pell and Gregory's classification helps to evidence possible difficulties in the procedures, and is used by the majority of surgeons, although there is little predictability of the difficulty of extraction by using this classification. 10 Analyzing the predictability of the degree of difficulty in the extraction of mandibular third molars by the Pedersen scale, the authors did not obtain results of the true difficulty, perhaps because the classification of Pell and Gregory and the Pedersen scale do not take the radicular anatomy into account. 11 Another classification of the degree of surgical difficulty was proposed taking into account the depth, relationship with the mandibular ramus and radicular anatomy, with the result of having better predictability with this new index than with the Pedersen scale. Even with good planning for the extraction procedure, the dental surgeon must be prepared for the accidents and complications that could occur. 12 Although it is considered minor oral surgery, the ideal is to perform the procedure with the patient lightly sedated and with local anaesthesia, and in some cases with general anaesthesia. Third molar surgeries generally have some type of post-operative morbidity such as pain and oedema. Some complications that may occur are lesions to nerves, particularly to the inferior alveolar and lingual nerves, which could be permanent. 13,14 Other accidents and complications that could occur are periodontal pocket formations in the distal region of the second molar, 15,16 mandibular fractures, 17,18,19 oroantral communication, displacement of the third molar into the maxillary sinus, 4,20 and infra-temporal fossa. 21 Reports of mandibular third molar displacements into other areas are rare, but they could cause serious complications. 20,22,23,24 Other precautions that should be taken are to avoid swallowing and aspiration of teeth. 25 Clinicians generally underestimate the health, economic and social implications that could cause these complications and accidents. 5 A study with 3.760 patients aged 25 years or over, in which 8.333 third molars were removed, alveolar osteitis was the most frequent post-operative problem found (up to 12.7%). Anaesthesia/paresthesia of the inferior alveolar nerve occurred at a frequency of up to 1.7%, while frequency of anaesthesia/paresthesia of the lingual nerve was 0.3%. All the other complications occurred with a frequency of l