Analysis in micro-CT and scanning electron microscopy of new instruments in retreatment and cleaning of flattened canals

• Ano de defesa: 2018
• Autor(a) principal: Borges, Mariana Maciel Batista
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Apical extrusion; Extrusão apical; Micro-CT; Reciprocating systems; Retratamento; Root canal retreatment; Sistemas reciprocantes; XP-Endo Shaper
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/25/25147/tde-19092018-182324/

The aim of this study was to evaluate the efficacy of heat-treated nickel-titanium reciprocating instruments and complementary techniques in retreatment of flattened canals. Material and methods: Twenty-six mandibular incisors were prepared up to size 25/.08 rotary file and filled using the single-cone technique. Subsequently, the teeth were divided into 3 groups (n=12) according to retreatment procedures: Reciproc Blue: R25 and R40; ProDesign R: PDR 25/.06 and PDR 35/.05; WaveOne Gold: WOG Primary and WOG Medium. The apically extruded material was collected in microtubes and the volume (mm³) was measured by Micro-CT. After this, the specimens received complementary cleaning with XP-Endo Shaper, PUI and 60° oscillatory instrumentation with #30 Hedströem file. Micro-CT scans were performed before and after removing filling material. After quantification of the volume of remaining filling material, the teeth were sectioned and scanning electron microscopy (SEM) images of the cervical, middle and apical thirds were obtained with a 700X magnification, and evaluated by scores based on the amount of filling material in the surface of dentine walls. Results: No reciprocating instrument promoted complete removal of filling material. All systems showed extrusion, however, WOG25 presented the higher extrusion of material (P<.05). XP-Endo Shaper significantly reduced the amount of filling material in the apical and middle thirds (P<.05). In the SEM analysis, there was no statistical difference among the cleaning methods (P> .05). Conclusions: The reciprocating instruments studied did not promote complete removal of root canal filling materials. XP-Endo Shaper, used as a complementary instrument in retreatment, improved removal of filling material.