1020 Compressive Deflection of Biodentine and Two Glass Ionomer Bases

Friday, March 23, 2012: 3:30 p.m. - 4:45 p.m.
Presentation Type: Poster Session
R. YAPP1, H. STRASSLER2, C. BRACHO-TROCONIS3, G. RICHARD4, and J. POWERS1, 1Dental Consultants, Inc, Ann Arbor, MI, 2Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD, 3Septodont, Confi-Dental Division, Louisville, CO, 4Septodont, St. Maur-des-Fosses, France

Objective: To determine the mechanical-support-equivalency of three materials used as bases below a composite. Base materials must develop adequate stiffness to support the restoration during masticatory loading. The stiffness of a new calcium silicate dentin substitute (B, Biodentine, Septodont) and two commercially successful glass ionomers (F, Fuji IX, GC America; V, Vitremer, 3M ESPE) was compared at 4 curing times when loaded in compression in a confined space similar to a Class I cavity. Methods: A stainless-steel test fixture composed of a base block and a matching square plate 1.85 mm-thick with a cylindrical hole 4.04 mm Φ drilled through it was assembled to produce a cylindrical cavity with one closed end. The materials were placed in this cavity and allowed to cure for the different time periods before applying a compressive load. Loading was performed using a flat-ended piston that closely fit the cavity and was driven into the cavity using a universal test machine (Instron 5866). Loading time points of 1/2, 1, 2, or 24 hours after initiation-of-mixing of the materials were used. The specimen was loaded to 1334 N with deflection measured at 500 and 1334 N. Results:

Base Material Deflection @ H Curing

Deflection @ 1 H Curing

Material

d@500 N, mm

d@1334 N, mm

d@500 N, mm

d@1334 N, mm

B

0.09(0.05)

0.17(0.06)

0.03(0.01)

0.07(0.01)

V

0.06(0.02)

0.10(0.02)

0.06(0.01)

0.12(0.02)

F

0.05(0.01)

0.09(0.02)

0.04(0.01)

0.07(0.02)

Conclusions: Biodentine at H after initial mixing at 500 N load deflected 50% and 80% more under load than for Vitremer and Fuji IX, respectively. By 1 H of curing, Biodentine deflected 50% less than Vitremer and 25% less than Fuji IX. Between H and 1 H, Biodentine was equivalent or slightly better at supporting load than Fuji IX or Vitremer. Funded in part by Septodont.

This abstract is based on research that was funded entirely or partially by an outside source: Septodont

Keywords: Glass ionomers, Loading, Mastication and dentine substitute