Fracture resistance of root filled molar teeth restored with glass fibre bundles.
OBJECTIVE
To evaluate the effect of unidirectional or woven glass fibre tapes inserted into MOD cavity preparations on the fracture resistance of root filled molar teeth.


METHODS
Extracted human molar teeth were randomly divided into six groups (n = 15) : G1 - sound teeth, control; G2 - MOD cavity preparation; G3 - MOD + root canal treatment (Endo); G4 - MOD + Endo + composite resin restoration (Resin); G5 - MOD + Endo + unidirectional fibre (UF) + Resin; G6 - MOD + ;Endo + woven fibre (WF) + Resin. The teeth were subjected to a compressive fracture test in a universal testing machine. After testing, two failure modes were classified: pulp chamber floor or cusp.


RESULTS
The highest and the lowest mean fracture strengths were found in sound teeth (G1) (4960N) and MOD + root canal treatment (G3) (612.84N), respectively, with significant differences from the other groups (P < 0.05). The remaining groups had statistically similar means. In G5 and G6, there was a tendency for fracture to occur in the pulp chamber floor compromising tooth integrity.


CONCLUSIONS
The insertion of glass fibres into MOD cavity preparations and restoring them with composite resin was not different than molar teeth filled with composite resin only in terms of fracture resistance. Fibres placed into MOD cavities do not reinforce teeth.
Rodrigues
F B
FB
Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
Paranhos
M P G
MP
Spohr
A M
AM
Oshima
H M S
HM
Carlini
B
B
Burnett
L H
LH
D000134:Acid Etching, Dental; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D019245:Compressive Strength; D003737:Dental Cavity Preparation / Q000379:methods; D003743:Dental Enamel / Q000293:injuries; D003764:Dental Materials / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000293:injuries; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis / Q000295:instrumentation; D005898:Glass / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D008298:Maleates / Q000737:chemistry; D008422:Materials Testing; D008963:Molar / Q000293:injuries / Q000473:pathology*; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012390:Root Canal Therapy / Q000379:methods*; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000503:physiopathology*; D019553:Tooth, Nonvital / Q000628:therapy*
D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D005899:Glass Ionomer Cements; D008298:Maleates; D012387:Root Canal Filling Materials; C009753:fiberglass; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; C040964:Ketac-Fil; D006171:Gutta-Percha