ABSTRACT
Forty-six single rooted extracted human teeth were used in this study. After cleaning and shaping, twenty canals were randomly selected for obturation with MTA placed in an orthograde manor (Group 1). Another twenty roots were obturated with gutta-percha and Kerr EWT sealer, using warm vertical compaction (Group 2). The apical 3 mm of each root in both groups were resected at approximately 45 degrees to its long axis. The teeth were aged for 48 h in a humidor. The root-ends of the teeth in Group 2 were then prepared and received MTA as a root-end filling material to a depth of 3 mm. Six roots were used as positive and negative controls. The roots of all teeth were placed in contact with India ink for 48 h. The roots were split and examined for dye leakage. There was no discernible leakage in teeth with resected MTA or those with MTA placed as a retrograde root-end filling material. We found no significant difference in dye leakage between resected MTA (Group 1) and non-resected MTA (Group 2). Based on these results it appears that the resection of set MTA does not affect its sealing ability.
Subject(s)
Aluminum Compounds/therapeutic use , Calcium Compounds/therapeutic use , Carbon , Dental Leakage/classification , Oxides/therapeutic use , Root Canal Filling Materials/therapeutic use , Silicates/therapeutic use , Aluminum Compounds/chemistry , Apicoectomy , Bisphenol A-Glycidyl Methacrylate/chemistry , Bisphenol A-Glycidyl Methacrylate/therapeutic use , Calcium Compounds/chemistry , Coloring Agents , Dental Bonding , Drug Combinations , Gutta-Percha/chemistry , Gutta-Percha/therapeutic use , Humans , Humidity , Oxides/chemistry , Retrograde Obturation , Root Canal Filling Materials/chemistry , Root Canal Obturation , Root Canal Preparation , Silicates/chemistry , Surface Properties , Time FactorsABSTRACT
The purpose of this study was to compare the rates of separation of 0.04 taper nickel titanium (NiTi) rotary instruments using two different instrumentation techniques. Twenty sets of 0.04 taper Profile Series 29 rotary instruments, sizes 2 to 6 were used in the mesial (mandibular) or buccal (maxillary) canals of extracted human molars with a 20 to 30 degree root curvature according to the Schneider classification. The rotary instruments were used up to 20 times either with the crown-down technique recommended by the manufacturer or with a combination of preflaring with hand files in a passive step-back technique followed by rotary instrumentation. Statistical analysis of the data showed that the combination technique allowed more uses before separation compared with the crown-down technique recommended by the manufacturer p < 0.0001.
