تقييم التقلص التصلبي لمواد تعويضية مؤقتة أساسها ثنائي ميتاكريلات مخبريا

الملخص EN

Background& Objective: Acrylic resin, poly-methacrylate provisional materials, have been no longer used because of low strength, poor marginal fit, low resistance, and color stability.

New resin systems, such as higher (meth) acrylates, and di-methacrylate were developed to improve the mechanical and physical properties.

Investigate polymerization shrinkage-strain, and Exo-thermic peak-temperatures of three new provisional materials based on di-methacrylate, and one of mono-methacrylate.

Materials & Methods: Three di-methacrylate based materials were used; Protemp3 Garant (PT3, Espe Dental AG, Germany), Tem Phase (TMP, Kerr, USA), and Luxatemp (LXT, dMg, Germany), and a mono-methacrylate-based material; Trim (TRM, Bosworth, USA).

Polymerization shrinkage-strain was measured using Bonded- disk method with initial specimen temperature at both 23 c, and 37 c, with values particularly noted at 5,10,120 min after mixing completion.

The setting reaction progress, and temperature dependence were evaluated in kinetic curves.

Exothermic peak-temperatures were recorded in a model test- cavity Overlying a thermocouple.

The specimens were pre-conditioned to 23c.

Temperature versus time, peak temperature and time to peak values were recorded, using T- Student, ANOVA, Schffe statistical analysis.

Results: Polymerization shrinkage- strain at 5min, and 23c0was only 0.1% for slow setting TRM.

For the di-methacrylates, LXT and PT3 were similar (2.3%), TMP was highest3.3%.

The mean exotherm of TRM was 5c0, but not significantly lower (p> 0.05) than those of T3P and LXT, but that of TMP was highest 12c0.

Conclusion: Di-methacrylates are better than mono-methacrylate temporary resins because of their high level of fillers, so rapid shrinkage during the first 5 mints of polymerization should be the lowest, and high temperature must be avoided in direct technique.