title: Mechanical or cold lateral compaction: The incidence of dentinal defects.
abstract: BACKGROUND
  The incidence of dentinal defects may influence the outcome of root canal treatment. The aims of this study were to evaluate and compare the incidence of dentinal defects following root canal obturation with two different techniques.
  
  
  METHODS
  A total of 110 mesial roots of human mandibular first molars were selected. Twenty-seven roots were left unprepared as negative controls (NCs). The mesiobuccal canals of 83 roots were prepared using rotary instruments. Twenty-seven roots were left unobturated as positive controls (PCs). Twenty-eight roots were obturated with cold lateral compaction (CLC) technique and the others were obturated with mechanical lateral compaction (MLC) technique. In the CLC and MLC groups, spreader penetration depth was measured by an electromechanical testing machine in canals containing master Gutta-percha cones. After root canal obturation, all the roots were sectioned horizontally at four levels from the apex and evaluated under a stereomicroscope at a magnification of ×40. The presence of dentinal defects was noted. Data were analyzed using the Chi-square and t-tests.
  
  
  RESULTS
  The number of defects was not significantly different between the CLC, MLC, and PC groups. The CLC, MLC, and PC groups had significantly more defects compared to the NC group.
  
  
  CONCLUSIONS
  According to the results of this study, the MLC and CLC techniques were the same in producing dentinal defects.
authors.affiliation: Dental Materials Research Center, Department of Endodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Seyed Mohsen
authors.initials: SM
authors.lastname: Hasheminia
authors.affiliation: Torabinejad Dental Research Center, Department of Endodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Farhad
authors.affiliation: Torabinejad Dental Research Center, Department of Endodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Saatchi
authors.affiliation: Dental Students Research Center, Department of Endodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hamidreza Sadegh
authors.initials: HS
authors.lastname: Nejad
authors.affiliation: Dental Students Research Center, Department of Endodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Sanei
keywords: Dental internal fit; Gutta-percha; dentin; root canal obturation; tooth fractures