Effect of alveolar bone height and fiber post length on the fracture resistance of endodontically treated maxillary central incisors / 中国组织工程研究

ABSTRACT

BACKGROUND:The elastic modulus of the fiber post is close to that of the dentine, so it can form a homogeneous whole and share the masticatory force, which can ease the stress concentration of dentine and prevent from tooth fracture. ＜br> OBJECTIVE:To investigate the effect of alveolar bone height and fiber post length on the fracture resistance of endodontical y treated maxil ary central incisors. ＜br> METHODS:Forty-eight human maxil ary central incisors were assigned randomly to six groups (n=8) of three different post insertion depths (5, 7, 9 mm) and two alveolar bone levels (2 and 5 mm) from the cement-enamel junction. Al of them were restored by glass fiber posts with composite resin core and cast metal crown. The samples were loaded in a testing machine with a crosshead speed of 1 mm/min at a 45° angle to the long axis of the tooth on the palatal surfaces until tooth fracture occurred. The maximum load and failure mode were recorded. ＜br> RESULTS AND CONCLUSION:Alveolar bone height had a significant influence on the fracture resistance (F=560.943, P>0.05), but fiber post length did not have a significant influence on it (P>0.05). Significant differences were found between the normal and resorbed alveolar bone groups in the number of repairable fracture patterns (χ2=5.689, P＜0.05). Under the circumstance of lowered alveolar bone height, lengthening fiber post cannot enhance fracture resistance of the teeth.