title: The effect of using RC prep during root canal preparation on the incidence of dentinal defects.
abstract: BACKGROUND
  The purpose of this in vitro study was to evaluate the effect of using RC Prep (Well-Prep, Vericom Co, Anyang, Korea) during root canal preparation on the incidence of defects in root canal walls.
  
  
  METHODS
  One hundred extracted mandibular incisors with single canals were randomly divided into 1 control group and 4 experimental groups (n = 20). The teeth in group 1 (control) were coronally flared with Gates Glidden drills (Mani, Japan), but no further preparation was made. All teeth in the experimental groups were first coronally flared with Gates Glidden drills and then prepared similarly by means of ProTaper instruments (Dentsply Maillefer, Ballaigues, Switzerland). The difference between the experimental groups was the following: in group 2, saline was used as an irrigation solution without the application of RC Prep; in group 3, teeth were irrigated with saline, and RC Prep was also applied to canals before the insertion of each file; in group 4, sodium hypochlorite (NaOCl) was used for irrigation without the application of RC Prep; and in group 5, both NaOCl and RC Prep were used. The apical root surface and horizontal sections 3, 6, and 9 mm from the apex were observed under a microscope. The presence of cracks was noted. The chi-square test and Fisher exact test were used for statistical analysis of differences between and among the groups.
  
  
  RESULTS
  A significant difference was found between and among the 5 groups (P < .05). Group 4 (NaOCl), which had the highest number of cracked teeth, was significantly different from group 1 (control) (P < .05). RC Prep, with both saline and NaOCl, had no significant effect on the incidence of microcrack formation (P > .05). When data were pooled, regardless of whether RC Prep was used, there was a significant difference between saline (groups 2 + 3) and NaOCl (groups 4 + 5) (P < .05).
  
  
  CONCLUSIONS
  RC Prep was unable to reduce the risk of dentinal defects. NaOCl caused more defects compared with saline.
authors.affiliation: Department of Endodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Adl
authors.affiliation: Department of Endodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Endodontics, School of Dentistry, Sanandaj University of Medical Sciences, Sanandaj, Iran. Electronic address: sedighm@sums.ac.ir.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Sedigh-Shams
authors.affiliation: Department of Endodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Marjan
authors.initials: M
authors.lastname: Majd
mesh_terms: D003387:Cracked Tooth Syndrome / Q000473:pathology; D003804:Dentin / Q000187:drug effects / Q000473:pathology*; D004492:Edetic Acid / Q000494:pharmacology*; D006801:Humans; D015994:Incidence; D010545:Peroxides / Q000494:pharmacology*; D018915:Root Canal Preparation; D012973:Sodium Hypochlorite / Q000494:pharmacology; D014508:Urea / Q000494:pharmacology*; D014885:Waxes / Q000494:pharmacology*
chemical_list: D010545:Peroxides; D014885:Waxes; C025081:RC-Prep; D014508:Urea; D004492:Edetic Acid; D012973:Sodium Hypochlorite
keywords: Dentinal defect; ProTaper; RC Prep; microcracks