The Pattern of Fracture of Endodontically Treated Teeth

It is well known that the primary function of a tooth is mastication. However, tooth fracture remains a major complication in endodontically-treated teeth. When the normal structure of a tooth is compromised by traumatic injuries, endodontic treatment remains the most viable option to maintain the tooth. However, endodontically treated teeth (ETT) exhibit greater brittleness and are more prone to fracture than non-ETT. It has been claimed that the inherent problems are mainly due to the drying of ETT over time and due to changes in their collagen cross-linking (1, 2). The main causes of failure in ETT are loss of retention of posts and/or crowns, secondary caries, and root fractures. Teeth that undergo root fracture usually have to be extracted (3, 4). In recent years, an increasing demand for endodontic treatment has been observed and (5), the purpose of the present study was to evaluate the pattern of fracture of ETT in adults. Case files extracted from the archives of our university between January 2005 and December 2009, were retrospectively analyzed. Cases with satisfactory periapical radiographs, ETT and fractured ETT were included in the study. For each case, fracture diagnosis was established from the following available retrospective records in the case files preopera-tive notes, periapical radiographs, and post-extraction evidence, as noted in the case files. Other items recorded were fracture types, and whether the tooth was used as an abutment or not, whether the tooth was posted or ve-neered and whether the abutment was a fixed or removable partial denture supporting. Vertical root fractures (VRF) were defined as fractures starting from the root, subgingivally, while cracks in teeth following root canal treatment (RCT) were considered cracks of the crown region , supragingivally. Out of 3000 examined case files, 755 were endodontically treated cases, of which 153 were disqualified for different reasons, as stated earlier. From the qualified 602 cases, 385 were females and 217 males, while posted and veneered teeth were 110 and 123 cases, respectively. Only 120 out of the 602 ETT suffered various forms of fractures, resulting in a fracture prevalence of 19.9% and were more in females (62%) than males (38%). Fractures were more frequent in the mandible (59.7%) compared with the maxilla (40.3%). First molars fractured more often (50%) (P < 0.05), while cusp fractures were the most frequent (55%), followed by VRF (28.7%), and tooth split (4.7%) (P < 0.05). No frank fracture was seen …