Fracture Resistance of Endodontically – Treated Premolars

M. Khoroushi, F. Sadeghzadeh, A. Nikbaght


Background and aim
This in vitro study compared the ability of horizontal pins and an adhesive resin cement to reinforce the facial cusp of endodontically treated maxillary premolars.

Methods and Materials
Seventy-two maxillary premolars were divided into six groups and mounted in acrylic blocks (n=12). In all of groups standardized endodontic treatment were completed. In groups 2-6 the palatal cusp were reduced, leaving the buccal cusp intact. In group 1 access cavity was filled with amalgam simply. The facial cusps of the teeth in other groups received one of the following reinforcements: Group 2- no reinforcement; Group 3- amalgam build up; Group 4- two horizontal dentinal pins; Group 5- Adhesive resin cement. Teeth in Group 6 were prepared for and restored with amalgam using two horizontal dentinal pins and adhesive resin cement. Then the lingual slope of the facial cusp of each specimen was loaded to failure using a compressive force. The mean fracture strengths for all groups were analyzed using statistical analysis. ( = 0.05). Fracture patterns and modes of failure were also evaluated.

The mean fracture values for groups were 1429.58; 701.80, 1242.50, 1298.63, 1289.25, 1311.83 kgf respectively. With the exception of group 1 (positive control group), group 6 were more fracture resistant than all other groups, and there were not significant difference between that group with groups 1 and 3-5.

The buccal cusp of endodontically treated maxillary premolars whether reinforced with a horizontal pins or adhesive resin cement were not significantly weaker than conservatively restore teeth.

Key Words
Fracture resistance; Pin; adhesive resin cement.

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