Slumping during sculpturing of composite materials

Abstract 

Objectives

This study investigated the slumping characteristics of four composite materials during sculpturing prior to their polymerization.

Methods

Four different composite materials were used to measure shape deformation due to slumping. Silicon impressions of the occlusal plane of three different molars were used as a mould for the composite samples. The surface of the samples was digitized with a laser scanner (400 slices, lateral resolution: 25μm). Scans were made after 1–4min. The 3D data sets were numerically superimposed with matching software and differences were calculated relative to the baseline measurement.

Results

The amount of surface deformation increases with increasing observation time. The average coefficient of variation was 0.2. The largest mean amount of slumping was observed for ELS with tooth mould 1 (150.0μm), and for Clearfil Majesty with tooth mould 2 (98.3μm) and mould 3 (42.8μm). Miris 2 Dentin and Synergy D6 Enamel were rather similar and seem to exhibit little deformation. The slump flow of ELS and Clearfil Majesty was up to 400% higher than the formers. The deformation could be sorted in the following order “mould 3”<“mould 2”<“mould 1” for all materials and all observation time. There was a significant influence (p<0.05) of the three factors, time, mould and composite type (ANOVA).

Significance

This specific method provides a reproducible approach for the assessment of the handling characteristics of composite materials. The results can identify slumping differences and assist in collecting information about the feasibility of a material for certain indications.

Keywords: Composite materials, Handling characteristics, Slumping, Sculpturing, Rheologic property