Flexural Strength of Three Provisional Restorative Materials

Objectives: Although provisional restorations are usually placed for a few weeks or less, they must still satisfy certain biologic, esthetic and mechanical requirements. Longer periods of use may be necessary when evaluating function, occluding vertical dimension and interocclusal distance during prosthetic restoration, or when replacing or stabilizing teeth during implant, periodontal or maxillofacial procedures. Therefore, it is important to know which effects, i.e., service conditions, may enhance or detrimentally affect mechanical properties, especially over an extended period. Methods: Flexure bars were fabricated from Jet Acrylic (Lang Dental Mfg. Co., Inc.), Protemp Garant (3M ESPE) and Integrity (Dentsply Caulk) brand provisional restorative materials. Nominal dimensions were 2mm (W) x 2mm (H) x 25mm (L). Ten specimens of each material were stored for 10, 30 and 182 days at room temperature (≈23 ^oC) or 37 ^oC and dry or submerged in distilled water. Specimens were tested in 3-point flexure (20mm span) on a mechanical testing apparatus at a crosshead speed of 1.0 mm min^-1. Maximum loads were recorded and flexural strength determined. A full factorial analysis was used to look at effects and their interactions on the response maximum flexural strength. Results: Material, storage temperature, storage medium, age, and the interaction between material and storage temperature, and storage temperature and storage medium were highly significant effects (Prob>F <.0001). Least squares mean strength of Integrity (96.1 MPa, SE 0.6) was significantly higher than Jet (61.4 MPa, SE 0.6) or Protemp Garant (60.1 MPa, SE 0.6). Water significantly reduces strength (Prob>F <.0001) for each material, regardless of storage temperature and time; conversely, body temperature (Prob>F <.0001) and increasing time (Prob>F <.0001) improved performance of all materials. Conclusion: Provisional restorative materials exhibit significantly different flexural strengths when stored over time and in different environmental conditions. This may be important when long-term provisionalization is indicated.

*3241 Flexural Strength of Three Provisional Restorative Materials*
G.A. THOMPSON, United States Army Dental Research Detachment, Great Lakes, IL, USA, and D.A. RUNYAN, United States Army Dental Research Detachment, Great Lakes, IL, USA Objectives: Although provisional restorations are usually placed for a few weeks or less, they must still satisfy certain biologic, esthetic and mechanical requirements. Longer periods of use may be necessary when evaluating function, occluding vertical dimension and interocclusal distance during prosthetic restoration, or when replacing or stabilizing teeth during implant, periodontal or maxillofacial procedures. Therefore, it is important to know which effects, i.e., service conditions, may enhance or detrimentally affect mechanical properties, especially over an extended period. Methods: Flexure bars were fabricated from Jet Acrylic (Lang Dental Mfg. Co., Inc.), Protemp Garant (3M ESPE) and Integrity (Dentsply Caulk) brand provisional restorative materials. Nominal dimensions were 2mm (W) x 2mm (H) x 25mm (L). Ten specimens of each material were stored for 10, 30 and 182 days at room temperature (≈23 ^oC) or 37 ^oC and dry or submerged in distilled water. Specimens were tested in 3-point flexure (20mm span) on a mechanical testing apparatus at a crosshead speed of 1.0 mm min^-1. Maximum loads were recorded and flexural strength determined. A full factorial analysis was used to look at effects and their interactions on the response maximum flexural strength. Results: Material, storage temperature, storage medium, age, and the interaction between material and storage temperature, and storage temperature and storage medium were highly significant effects (Prob>F <.0001). Least squares mean strength of Integrity (96.1 MPa, SE 0.6) was significantly higher than Jet (61.4 MPa, SE 0.6) or Protemp Garant (60.1 MPa, SE 0.6). Water significantly reduces strength (Prob>F <.0001) for each material, regardless of storage temperature and time; conversely, body temperature (Prob>F <.0001) and increasing time (Prob>F <.0001) improved performance of all materials. Conclusion: Provisional restorative materials exhibit significantly different flexural strengths when stored over time and in different environmental conditions. This may be important when long-term provisionalization is indicated.
Seq #344 - Prosthodontic Polymers 10:15 AM-11:30 AM, Saturday, 13 March 2004 Hawaii Convention Center Exhibit Hall 1-2
Back to the Dental Materials: VI - Polymer Materials-Mechanical Properties and Degradation Program Back to the IADR/AADR/CADR 82nd General Session (March 10-13, 2004)
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