title: Dentinal defects before and after rotary root canal instrumentation with three different obturation techniques and two obturating materials.
abstract: OBJECTIVE
  To evaluate the role of rotary root canal instrumentation followed by obturation with three different techniques and two different materials on the incidence of dentinal defects.
  
  
  METHODS
  One hundred and sixty mandibular premolars were divided into eight groups (n = 20). Group I was left untreated and served as control. The other seven groups were prepared with profile rotary instruments till #40.06 taper. After preparation, group II was left unfilled, groups III, IV, and V were obturated with Gutta-percha and AH Plus sealer using passive technique, lateral compaction and warm vertical compaction, respectively. Groups VI, VII, and VIII were obturated with Resilon and Realseal sealer using passive technique, lateral compaction, and warm vertical compaction, respectively. Roots were then sectioned at 3, 6, and 9 mm from the apex and inspected under a stereomicroscope (50×) for dentinal defects. Chi-square test was performed to compare the incidence of dentinal defects between the groups (P < 0.05).
  
  
  RESULTS
  The unprepared control group had no dentinal defects. The instrumentation group (group II) and the obturation group (groups III-VIII) showed significantly more defects than the uninstrumented control group (group I) (P < 0.001). There was no significant difference between the root canal obturating techniques (group III-VIII) when compared with the instrumentation group (group II). On inter group comparison among the obturation groups the number of defects after lateral compaction with Gutta-percha (group IV) was significantly larger than passive Gutta-percha obturation (group III) (P < 0.05).
  
  
  CONCLUSIONS
  The results suggest that root canal instrumentation significantly influenced the incidence of dentinal defects or fracture. Dentinal defects were more significantly attributed to the role of root canal instrumentation rather than the type of obturation technique or material. Lateral compaction with Gutta-percha significantly produces more defects than passive Gutta-percha obturation.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Ponnuswamy
authors.initials: P
authors.lastname: Kumaran
authors.affiliation: Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Elangovan
authors.initials: E
authors.lastname: Sivapriya
authors.affiliation: Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Jamuna
authors.initials: J
authors.lastname: Indhramohan
authors.affiliation: Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Velayutham
authors.initials: V
authors.lastname: Gopikrishna
authors.affiliation: Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: K Subramani
authors.initials: KS
authors.lastname: Savadamoorthi
authors.affiliation: Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Angambakkam Rajasekharan
authors.initials: AR
authors.lastname: Pradeepkumar
keywords: Dentin defects; obturation techniques; real seal; resilon; root canal instrumentation; vertical root fracture