RESUMO
This study examined the effect of three sealers and four irrigants on retention of Dentatus preformed posts luted with Panavia 21 resin cement. Gutta-percha with one of the following sealers--EWT, AH26, Nogenol, or no sealer (control)--was used to fill the root canals of 160 autoclaved incisor and premolar tooth roots. After 72 hr 8 mm post spaces were created with Dentatus Probos Pathfinders and Dentatus reamers. After irrigating the post spaces with saline, 5.25% NaOCl, 50% citric acid followed by NaOCl, or 40% H3PO4, followed by NaOCl, Panavia 21 TC cement was introduced into the canal on the Dentatus #4 stainless steel post's threads. An up-and-down and counterclockwise motion and then a forward twist seated the posts without engaging dentin. Mesiodistal and faciolingual radiographs visualized the chambers. After 72 hr posts were removed axially with an Instron at 5 mm/min. Surprisingly, using Nogenol sealer reduced post retention whereas EWT and AH26 increased retention compared with no sealer. Post retention improved after acid etchants, especially for AH26.
Assuntos
Cimentação , Retenção de Dentadura , Resinas Epóxi , Técnica para Retentor Intrarradicular , Cimentos de Resina/química , Materiais Restauradores do Canal Radicular/química , Irrigantes do Canal Radicular/química , Condicionamento Ácido do Dente , Análise de Variância , Dente Pré-Molar , Bismuto/química , Ácido Cítrico/química , Análise do Estresse Dentário , Desinfetantes/química , Combinação de Medicamentos , Eugenol/química , Ácidos Graxos/química , Guta-Percha/química , Humanos , Incisivo , Metenamina/química , Fosfatos/química , Ácidos Fosfóricos/química , Resinas Vegetais/química , Preparo de Canal Radicular/instrumentação , Salicilatos/química , Prata/química , Hipoclorito de Sódio/química , Aço Inoxidável/química , Estresse Mecânico , Timol/química , Titânio/química , Óxido de Zinco/químicaRESUMO
This study compared external root stresses from instrumentation by several motor-driven nickel-titanium instruments to stresses developed by hand files. Twelve curved first molar mesial roots were invested in PLM-9 photoelastic material to disclose net stress transmitted from the canal through the dentin. Minimal fringe patterns were observed during instrumentation with all techniques. Light-speed yielded the least change. In no case was a complete 60 psi fringe change noted.