Resistance to fracture of endodontically treated teeth restored with different post systems.

STATEMENT OF PROBLEM Very little is known about the resistance to fracture of endodontically treated teeth restored with newly developed esthetic post systems. Purpose. This in vitro study compared the effect of 1 titanium and 3 esthetic post systems on the fracture resistance and fracture patterns of crowned, endodontically treated teeth. MATERIAL AND METHODS A total of 40 recently extracted human maxillary canines with their crowns removed were endodontically treated. Four groups of 10 specimens were formed. Teeth were restored with titanium, quartz fiber, glass fiber, and zirconia posts and numbered as groups 1, 2, 3, and 4, respectively. All posts were cemented with Single Bond dental adhesive system and dual-polymerizing RelyX ARC adhesive resin cement. All teeth were restored with composite cores, and metal crowns were fabricated and cemented with glass ionomer cement. Each specimen was embedded in acrylic resin and then secured in a universal load-testing machine. A compressive load was applied at a 130-degree angle to the long axis of the tooth until fracture, at a crosshead speed of 1 mm/min. One-way analysis of variance and a Tukey test were used to determine the significance of the failure loads between groups (P<.001). A non-parametric chi(2) test was conducted for evaluation of the mode of failure (P<.001). RESULTS The mean failure loads (kg) were 66.95, 91.20, 75.90, and 78.91 for groups 1 to 4, respectively. Teeth restored with quartz fiber posts (group 2) exhibited significantly higher resistance to fracture (P<.001) than the other 3 groups. Teeth restored with glass fiber and zirconia posts (groups 3 and 4) were statistically similar (P>.05). Fractures that would allow repair of the tooth were observed in groups 2 and 3, whereas unrestorable, catastrophic fractures were observed in groups 1 and 4 (P<.001). CONCLUSION Within the limitations of this study, significantly higher failure loads were recorded for root canal treated teeth restored with quartz fiber posts. Fractures that would allow repeated repair were observed in teeth restored with quartz fiber and glass fiber posts.

[1]  T. Watson,et al.  Intermittent loading of teeth restored using quartz fiber, carbon-quartz fiber, and zirconium dioxide ceramic root canal posts. , 1999, The journal of adhesive dentistry.

[2]  A. J. Goldberg,et al.  The use of continuous fiber reinforcement in dentistry. , 1992, Dental materials : official publication of the Academy of Dental Materials.

[3]  H. Messer,et al.  Reduction in tooth stiffness as a result of endodontic and restorative procedures. , 1989, Journal of endodontics.

[4]  J. Astbäck,et al.  A retrospective study of 236 patients with teeth restored by carbon fiber-reinforced epoxy resin posts. , 1998, The Journal of prosthetic dentistry.

[5]  J. Martinoff,et al.  Clinically significant factors in dowel design. , 1984, The Journal of prosthetic dentistry.

[6]  A. H. Tjan,et al.  Microleakage of composite resin cores treated with various dentin bonding systems. , 1991, The Journal of prosthetic dentistry.

[7]  J A Sorensen,et al.  Effect of post adaptation on fracture resistance of endodontically treated teeth. , 1990, The Journal of prosthetic dentistry.

[8]  J. Burgess,et al.  The resistance to tensile, compression, and torsional forces provided by four post systems. , 1992, The Journal of prosthetic dentistry.

[9]  B. Akkayan,et al.  Resistance to fracture of crowned teeth restored with different post systems. , 1998, The European journal of prosthodontics and restorative dentistry.

[10]  L A Lang,et al.  The effects of dowel design and load direction on dowel-and-core restorations. , 2001, The Journal of prosthetic dentistry.

[11]  J. Stannard,et al.  Strength of roots before and after endodontic treatment and restoration. , 1992, Journal of endodontics.

[12]  G. Goldstein,et al.  Restoration of endodontically treated teeth: a review of the literature. , 1986, The Journal of prosthetic dentistry.

[13]  M. Behr,et al.  Comparison of in vitro fracture strength of metallic and tooth-coloured posts and cores. , 2000, Journal of oral rehabilitation.

[14]  Libman Wj,et al.  Load fatigue of teeth restored with cast posts and cores and complete crowns. , 1995 .

[15]  J. Martinoff,et al.  Intracoronal reinforcement and coronal coverage: a study of endodontically treated teeth. , 1984, The Journal of prosthetic dentistry.

[16]  N. Creugers,et al.  An analysis of durability data on post and core restorations. , 1993, Journal of dentistry.

[17]  M Heller,et al.  Mechanical properties and short-term in-vivo evaluation of yttrium-oxide-partially-stabilized zirconia. , 1989, Journal of biomedical materials research.

[18]  M. Trope,et al.  Resistance to fracture of endodontically treated roots. , 1992, Oral surgery, oral medicine, and oral pathology.

[19]  S Kwiatkowski,et al.  A preliminary consideration of the glass-ceramic dowel post and core. , 1989, The International journal of prosthodontics.

[20]  J. Nicholls,et al.  In vitro comparison of intact endodontically treated teeth with and without endo-post reinforcement. , 1979, The Journal of prosthetic dentistry.

[21]  D Assif,et al.  Biomechanical considerations in restoring endodontically treated teeth. , 1994, The Journal of prosthetic dentistry.

[22]  P. Vallittu.  A review of fiber-reinforced denture base resins. , 1996, Journal of prosthodontics : official journal of the American College of Prosthodontists.

[23]  A. Caputo,et al.  Retention and stress distribution of tapered-end endodontic posts. , 1986, The Journal of prosthetic dentistry.

[24]  D. Nathanson,et al.  Effects of moisture content and endodontic treatment on some mechanical properties of human dentin. , 1992, Journal of endodontics.

[25]  Jon P Standlee,et al.  Biomechanics in Clinical Dentistry , 1987 .

[26]  E Asmussen,et al.  Stiffness, elastic limit, and strength of newer types of endodontic posts. , 1999, Journal of dentistry.

[27]  H. Messer,et al.  Are endodontically treated teeth more brittle? , 1992, Journal of endodontics.

[28]  G. Heydecke,et al.  Survival rate and fracture strength of endodontically treated maxillary incisors with moderate defects restored with different post-and-core systems: an in vitro study. , 2001, The International journal of prosthodontics.

[29]  A. Caputo,et al.  Pins and posts--why, when and how. , 1976, Dental clinics of North America.