Effect of accelerated ageing and surface sealing on the permanent deformation of auto-polymerising soft linings.
OBJECTIVE
To compare the effects of different ageing methods on the permanent deformation of two permanent soft liners.


METHODS
The materials selected were auto-polymerising acrylic resin and silicone-based reliners. Sealer coating was also evaluated. Sixty specimens of each reliner were manufactured (12.7 mm diameter and 19 mm length). Specimens were randomly distributed into 12 groups (n = 10) and submitted to one of the accelerated ageing processes. Permanent deformation tests were conducted with a mechanical device described within the American Dental Association specification number 18 with a compressive load of 750 gf applied for 30 s. All data were submitted for statistical analysis. Mann-Whitney test compared the effect of the surface sealer on each material and the permanent deformation of the materials in the same ageing group (p = 0.05). Kruskal-Wallis and Dunn tests compared all ageing groups of each material (p = 0.05).


RESULTS
The silicone-based reliner presented a lower permanent deformation than the acrylic resin-based reliner, regardless of the ageing procedure. The surface sealer coating was effective only for the thermocycled silicone group and the accelerated ageing processes affected only the permanent deformation of the acrylic resin-based material.


CONCLUSIONS
The silicone-based reliner presented superior elastic properties and the thermocycling was more effective in ageing the materials.
da Silva
Joaquim
J
Oral Sciences School, Amazonas State University, Manaus, Amazonas, Brazil.
Takahashi
Jessica
J
Nuňez
Juliana
J
Consani
Rafael
R
Mesquita
Marcelo
M
D000180:Acrylic Resins / Q000737:chemistry*; D003799:Dental Stress Analysis; D003822:Denture Liners; D006801:Humans; D008422:Materials Testing; D010895:Pit and Fissure Sealants / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry*; D013696:Temperature
D000180:Acrylic Resins; D010895:Pit and Fissure Sealants; D012828:Silicones