Pre-heating effects on extrusion force, stickiness and packability of resin-based composite

Jiawei Yang; Nikolaos Silikas; David C Watts

doi:10.1016/j.dental.2019.08.101

Pre-heating effects on extrusion force, stickiness and packability of resin-based composite

Dent Mater. 2019 Nov;35(11):1594-1602. doi: 10.1016/j.dental.2019.08.101. Epub 2019 Aug 30.

Authors

Jiawei Yang¹, Nikolaos Silikas², David C Watts³

Affiliations

¹ Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK.
² Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK. Electronic address: nick.silikas@manchester.ac.uk.
³ Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK; Photon Science Institute, University of Manchester, Manchester, UK. Electronic address: david.watts@manchester.ac.uk.

PMID: 31477247
DOI: 10.1016/j.dental.2019.08.101

Abstract

Objectives: To measure temperature effects on stickiness and packability of representative resin-based composites and the effect of pre-heating time on pre-cure properties of Viscalor, including extrusion force.

Methods: Five resin-based composites (RBC) and an additional RBC, Viscalor, used with a Caps Warmer (VOCO, Germany) were studied. The extrusion force (N) and extruded mass (g) were measured from Viscalor compules heated in T3 mode for 30s (T3-30s) and 3min (T3-3min). For stickiness and packability measurements, RBCs were packed into a brass cylindrical cavity controlled at 22 and 37°C. A flat-ended probe was lowered into the RBC pastes at constant speed. Stickiness: F_max (N) and W_s (N mm), and packability: F_p (N), were measured. Viscalor was LED photo-cured at 1200mW/cm² for 40s. The degrees of conversion at 5min and 24h post cure (DC_5min and DC_24h) of Viscalor (no heat, T3-30s and T3-3min) were measured by ATR-FTIR. Data were analysed by one-way ANOVA, independent t-test and Tukey post-hoc tests (p<0.05).

Results: The maximum temperature of the Caps Warmer, in T3 mode, reached 68°C in 20min. Viscalor temperatures of 34.5°C and 60.6°C were recorded after 30s and 3min pre-heating, respectively. Pre-heating significantly reduced extrusion force and increased extruded mass, especially after 3min. RBCs varied in F_max, W_s and F_p (p<0.05). Temperature also affected F_max (p=0.000), W_s (p=0.002) and F_p (p=0.000). Pre-heating Viscalor for either 30s or 3min did not increase the post-cure DC at either 5min or 24h, relative to no pre-heating (p>0.05).

Significance: The composites varied to an extent in stickiness and packability but the overall magnitudes remained within a clinically acceptable range. Pre-heating was beneficial in placement of Viscalor and caused no adverse effects through premature polymerization.

Keywords: Degree of conversion; Extrusion force; Handling properties; Preheating; Resin composite; Stickiness.

MeSH terms

Composite Resins*
Dental Materials
Heating*
Materials Testing
Mechanical Phenomena
Polymerization

Substances

Composite Resins
Dental Materials