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Abstract
The progressive extension of caries lesion on root of teeth presented a problem in dentistry for providing the patients with high strength and durable restorations. Reconstructing endodontically treated teeth requires a special preparation to increase their fracture resistance. This in-vitro study concerned with the possible incomplete crown ferrule effect on fracture resistance of endodontically treated teeth restored with fiber post and all ceramic crown.
Twenty mandibular premolars were decoronated and endodontically treated and grouped randomly into four groups, placed in mold filled with epoxy resin. Teeth were prepared in special way to provide complete ferrule, incomplete ferrule on one, two, three axial walls according to the group respectively, in a special milling machine to receive all ceramic crowns.
Fiber posts were cemented into prepared post spaces inside root using adhesive resin cement (Panavia F 2.0).
Standardized cores were built using standard core former and composite resin filling.
Final preparation of the teeth were made on a milling machine to standard angled preparation for all teeth.
Wax patteren was made on one tooth and a rubber base mold was taken of this wax patteren and used to produce wax patterns for all teeth of same size and shape.
Wax patterns were invested to produce pressable all ceramic crowns that were cemented to teeth using adhesive resin cement (Panavia F 2.0).
Specimens were compressively loaded to failure in a universal load testing machine and fracture loads were recorded in Newtons.
Results were tabulated and statistically analyzed. Results showed that group one with complete ferrule had the highest fracture resistance followed by group II with three walls ferrule, group III with two walls ferrule and finally group IV with one wall ferrule which showed the lowest fracture resistance.
Statistical analysis showed that there was statistical difference between the four groups.
This study concluded the four wall ferrule produced the highest fracture resistance results followed by the three ferrule wall. Also the one ferrule wall produced the lowest fracture resistance results with fracture pattern that affected the cervical part of the root.