Effect of a denture cleanser on weight, surface roughness, and tensile bond strength of two resilient denture liners.
BACKGROUND
Denture cleansers used in clinical practice can damage resilient denture lining materials.


OBJECTIVE
This study evaluated the effects of a denture cleanser on weight change, roughness, and tensile bond strength on 2 denture resilient lining materials.


METHODS
Forty specimens of microwave acrylic resin (Onda-Cryl), 30 mm in diameter and 4 mm thick, were prepared to verify weight change and surface roughness. The specimens were divided into 4 groups consisting of 10 specimens each, relined with a resilient liner (Coe Soft or Dentusoft), and treated (Polident or tap water). To evaluate tensile bond strength, 12 specimens were used for each group. All specimens were stored in artificial saliva for 15 days, immersed once a day in Polident or tap water, and evaluated at 0 hours and after 24 hours and 7 and 15 days. Roughness was evaluated by use of a profilometer. Weight changes were recorded in milligrams and expressed as the percentage of weight difference between the periods of evaluation. Tensile bond strength was determined with a universal testing machine. The specimens were placed under tension until failure by a cross-speed of 5 mm/min with a 500 Kg load cell. The type of failure was determined by use of stereoscopic microscopy at original magnification x8. The data were submitted to analysis of variance and compared by Tukey's test (alpha=.05).


RESULTS
Specimens immersed in Polident showed higher and significant (P<.05) weight changes (%) than those immersed in water between 24 hours and 7 days (Coe Soft-Polident: 0.48 +/- 0.09; Coe Soft-water: 0.28 +/- 0.09; Dentusoft-Polident: 0.44 +/- 0.16; Dentusoft-water: 0.22 +/- 0.15) and between 7 and 15 days (Coe Soft-Polident: 0.08 +/- 0.04; Coe Soft-water: -0.17 +/- 0.05; Dentusoft-Polident: 0.01 +/- 0.04; Dentusoft-water: - 0.24 +/- 0.03). There was significant difference (P<.05) in roughness (in micrometers), between treatments after 7 days (Coe Soft-water: 4.07 +/- 0.22; Coe Soft-Polident: 3.36 +/- 0.52; Dentusoft-water: 3.68 +/- 0.72; Dentusoft-Polident: 3.26 +/- 0.41) and 15 days (Coe Soft-water: 4.88 +/- 0.29; Coe Soft-Polident:3.53 +/- 0.61; Dentusoft-water: 4.42 +/- 1.12; Dentusoft-Polident: 3.68 +/- 0.37). Tensile bond strength was highest (P<.05) after 15 days (Coe Soft-water: 5.19 +/- 0.93; Coe Soft-Polident: 4.40 +/- 0.38; Dentusoft-water: 4.42 +/- 1.15; Dentusoft-Polident: 4.84 +/- 1.14). Most failures were cohesive (Coe Soft: 76.04% and Dentusoft: 82.29%).


CONCLUSIONS
Within the limitations of this in vitro study, specimens immersed in Polident demonstrated increased weight changes of resilient liners when compared with tap water, but surface roughness and tensile bond strength were unaffected.
Garcia
Renata M C Rodrigues
RM
Department of Periodontics and Prosthodontics, School of Dentistry Piracicaba, University of Campinas, São Paulo, Brazil. regarcia@fopunicamp.br
Léon
Blanca T L
BT
Oliveira
Viviane B M
VB
Del Bel Cury
Altair A
AA
D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D001881:Borates / Q000737:chemistry; D001840:Dental Bonding; D003820:Denture Cleansers / Q000737:chemistry*; D003822:Denture Liners; D006801:Humans; D008422:Materials Testing; D012464:Saliva, Artificial / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; D001881:Borates; D003820:Denture Cleansers; D012464:Saliva, Artificial; D013431:Sulfates; D014867:Water; C102654:Polident