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BACKGROUND: Teeth with apical periodontitis that either persisted or developed after initial root canal treatment is most often indicated for retreatment procedure. The present study was conducted to compare the WaveOne and NeoEndo retreatment file system for the removal of gutta-percha from the root canal. MATERIALS AND METHODS: Fifty extracted mandibular first premolars with single straight roots were divided into two groups, Group I-WaveOne and Group II-NeoEndo. All samples were scanned with cone-beam computed tomography after the root filling and retreatment procedures. The decrease in the volume of filling material after each retreatment protocol was measured. RESULTS: The mean volume of gutta-percha in Group I before retreatment was 5.6 and in Group II was 5.3, after retreatment in Group I was 2.7, and in Group II was 4.2. The mean percentage reduction in Group I was 45.2% and in Group II was 23.8%. The difference was significant (P < 0.05). CONCLUSION: Both systems failed to completely remove gutta-percha. WaveOne was significantly more effective than the NeoEndo retreatment system.
RESUMO
INTRODUCTION: Endodontically treated teeth dry with time, and its dentin undergoes changes making the teeth brittle and friable. The main function of a post is to strengthen or reinforce a weakened root. However, doing a post and core frequently requires the removal of sound tooth tissue. Recent materials introduced in the market for post and cores have been promising. AIM: The aim of this study is to evaluate the fracture resistance of endodontically treated extracted permanent teeth with variable remaining root dentin thickness after post space preparation. MATERIALS AND METHODS: A total of 270 freshly extracted permanent maxillary central incisors with fully formed apices were selected, decoronated at cementoenamel junction, and divided into three main groups according to remaining root dentin thickness, determined using a Vernier caliper into 0.5, 1, and 1.50 mm after post space preparation. Each group was further divided into three subgroups (subgroup a: Custom-made cobalt-chromium alloy post and core; subgroup b: Prefabricated glass fiber post and composite core; and subgroup c: EverStick fiber post). Each specimen was subjected to compressive load using universal testing machine. The force required to fracture was recorded and data were analyzed using analysis of variance (ANOVA) test. RESULTS: Analysis of variance revealed that compressive strength of the tooth is significantly affected by the increase in the remaining dentin thickness after post space preparation (p < 0.05). Furthermore, teeth with custom fabricated posts showed a significantly higher compressive strength (p < 0.05) than prefabricated glass fiber post and EverStick fiber post groups except the group with minimum remaining dentin thickness. CONCLUSION: The present in vitro study revealed that compressive strength of the post and core systems is directly related to the amount of healthy remaining dentin thickness. Hence, efforts to maximize the preservation of natural dentin should be taken during post space preparation.