Effects of instrumentation, root canal obturation and fiber post application on dentin crack initiation

instrumentation, root canal obturation and fiber post application

Abstract

Aim: The objective of this investigation was to evaluate the occurrence of fracture initiation in root dentin following root canal instrumentation, filling, and fibre post application. Methods: 150 extracted premolars were chosen at random and grouped into four major groups with 15 subgroups (n=10): group 1 (n=10), control, not instrumented; group 2 (n=20), the half were prepared to WaveOne size 25# or 40# respectively; group 3 (n=40), prepared same with group 2, then each subgroup was further divided with one half filling with lateral compaction or continuous wave compaction respectively; group 4 (n=80), prepared and filled same with group 3, then the lateral and continuous wave compaction groups were respectively divided by restoration with RelyXTM or RTD fiber posts. All roots were split perpendicular to the long axis at three points: 3 mm, 5 mm, and 7 mm from the apex, and then examined using a stereomicroscope. Cracks were counted and statistically examined based on their lack or presence. Results: No cracks were observed in unprepared and the only instrumented groups. Fiber post application significantly increased the crack formation (P < .05). Lateral compaction filling caused significantly more cracks than continuous wave compaction after fiber post application (P < .05). The cracks increased by the two kinds of fiber post showed significant difference. Conclusions: Fiber post space preparation mainly contributes to the dentin crack formation. When combined with fiber post application, continuous wave compaction produced less dentin cracks compared to lateral compaction filling.