A new polyisoprene-based light-curing denture soft lining material.
OBJECTIVE
The purpose of this study was to investigate some clinically relevant properties of Clearfit LC, a newly developed polyisoprene-based light-curing lining material. Its properties were compared with those of other four commercial products.


METHODS
Five soft lining materials, Clearfit LC, two plasticised acrylics (Super-soft, Soften) and two silicones (Molloplast B, Sofreliner) were used to determine water sorption, solubility, staining resistance, Shore A hardness and shear bond strength to denture base. Five specimens for each test were fabricated. The results of each test among the five materials were compared by one-way ANOVA and Scheffe's post-hoc test at alpha=0.05.


RESULTS
One-way ANOVA of each test showed that the differences among five materials were significant (P<0.05). Clearfit LC showed the intermediate water sorption and solubility (10.07; 1.72 microg/mm(3)). It also showed the lowest color change in beta-carotene/olive oil solution and instant coffee solution (DeltaE=1.19, 5.48, respectively). The shear bond strength of Clearfit LC was 1.56MPa, and no adhesive failure was found. Its Shore A hardness value (56.2) was located between two acrylics and silicones. It was also found that the softer materials tend to failure cohesively.


CONCLUSIONS
The polyisoprene-based lining material showed low water sorption and solubility, moderate softness, high staining resistance and satisfactory shear bond strength to denture base resin. It also provides clinicians sufficient working time due to its light-curing property. It would be an attractive alternative as a relining material.
Department of Complete Denture Prosthodontics Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, 113-8549, Tokyo, Japan. i.hayakawa.ore@tmd.ac.jp
Iwao
I
Hayakawa
En-Sheng
ES
Keh
Masayuki
M
Morizawa
Gaku
G
Muraoka
Shigezo
S
Hirano
D000042:Absorption; D000180:Acrylic Resins / Q000737:chemistry; D000704:Analysis of Variance; D001672:Biocompatible Materials / Q000737:chemistry*; D002070:Butadienes / Q000737:chemistry*; D003116:Color; D001840:Dental Bonding; D003819:Denture Bases; D003822:Denture Liners; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D006244:Hardness; D045782:Hemiterpenes; D006801:Humans; D008027:Light; D008422:Materials Testing; D010420:Pentanes; D010968:Plasticizers / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012826:Silicone Elastomers / Q000737:chemistry; D012995:Solubility; D013314:Stress, Mechanical; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; D001672:Biocompatible Materials; D002070:Butadienes; D004129:Dimethylpolysiloxanes; D045782:Hemiterpenes; C020964:MDX 4-4210; D010420:Pentanes; D010968:Plasticizers; D011108:Polymers; D012826:Silicone Elastomers; D014867:Water; C005059:isoprene; D019904:Polymethyl Methacrylate