An in vitro study into the effect of the ferrule preparation on the fracture resistance of crowned teeth incorporating prefabricated post and composite core restorations.
OBJECTIVE
This in vitro study investigated the effect of a ferrule preparation on the fracture resistance of crowned central incisors incorporating a prefabricated post (Parapost) cemented with Panavia-Ex and with a composite core.


METHODS
The test group consisted of 10 post crowned natural central incisor teeth with a 2-mm wide ferrule preparation, whilst the control group of 10 teeth had no ferrule. The specimens were mounted on a Lloyd universal testing machine and a compressive load was applied at an angle of 135 degrees to the palatal surface of the crown until failure occurred.


RESULTS
In both groups, failure occurred at higher loads compared with previous studies. The mean failure load was 1218 N for the unferruled group and 1407 N for the ferruled group. Statistical analysis showed no significant difference between the groups.


CONCLUSIONS
Under the conditions of this study, when composite cement and core materials are utilized with a Parapost prefabricated system in vitro the additional use of a ferrule preparation has no benefit in terms of resistance to fracture.
al-Hazaimeh
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Division of Restorative Dentistry, Leeds Dental Institute, Clarendon Way, Leeds, LS2 9LU, UK.
Gutteridge
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D002484:Cementation; D003188:Composite Resins / Q000737:chemistry; D019245:Compressive Strength; D003442:Crowns; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D007180:Incisor / Q000503:physiopathology*; D010710:Phosphates / Q000737:chemistry; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry; D013223:Statistics as Topic; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000503:physiopathology; D019231:Tooth Preparation, Prosthodontic; D014092:Tooth Root / Q000293:injuries
D003188:Composite Resins; D010710:Phosphates; D019279:Resin Cements; C052304:Panavia EX