Effects of root canal preparation, various filling techniques and retreatment after filling on vertical root fracture and crack formation.
OBJECTIVE
To investigate the incidence of cracks in root dentin after rotary instrumentation and filling with cold lateral condensation (CL), single-cone obturation (SC), and warm vertical compaction (WV) and retreatment of each filling system.


METHODS
One-hundred sixty mandibular incisors were selected. Twenty teeth were left unprepared and served as a control, and the remaining 140 teeth were instrumented. Twenty teeth were assigned to an only prepared group. The remaining 120 teeth were assigned to three root canal filling groups and three retreatment groups (n = 20), as follows: CL, WV, SC, and retreatment of each filling system. All the roots were sectioned perpendicular to the long axis at 2, 4, 6, and 8 mm from the apex, and the sections were then observed under a stereomicroscope. The absence/presence of cracks and vertical root fractures were recorded, and the data were analyzed with a Pearson's chi-square test (P = 0.05).


RESULTS
No complete vertical root fractures were observed in the unprepared and only prepared groups. However, vertical fractures were observed in the filling and retreatment groups. There were significantly more cracks in the retreatment after WV group than the other groups, with the exception of the retreatment after SC, WV, and CL resulted in significantly more cracks than the only prepared and SC.


CONCLUSIONS
The filling techniques (except SC) caused more cracks than preparation only. The SC caused fewer cracks compared to the other filling techniques. The retreatment following the different filling techniques (except CL) caused more cracks than the original fillings.
Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
Ismail Davut
ID
Capar
Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
Gokhan
G
Saygili
Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
Hazal
H
Ergun
Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
Tuba
T
Gok
Department of Endodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey.
Hakan
H
Arslan
Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
Huseyin
H
Ertas
D003786:Dental Pulp Cavity / Q000473:pathology*; D006801:Humans; D012387:Root Canal Filling Materials / Q000737:chemistry*; D018915:Root Canal Preparation; D014092:Tooth Root / Q000473:pathology
D012387:Root Canal Filling Materials
Root fracture; cracks; dentinal damage; retreatment; root canal filling; root canal instrumentation