[Silver-ion release and particle distribution of denture base resin containing nanometer-sized silver-supported antimicrobial agent].
OBJECTIVE
To investigate the distribution of antimicrobial agent STR-1 of nanometer level which was incorporated with ball-grinding method in the polymethylmethacrylate (PMMA) denture base, and to study the release mode of silver ions from the base.


METHODS
The distribution of the antimicrobial agent in the PMMA denture base containing STR-1 at concentrations of 0 g/L, 5 g/L, and 10 g/L was examined with scanning electronic microscopy. Then, PMMA resin bases containing STR-1 at the three concentrations were respectively immersed in artificial saliva at 37 degrees C for 54 days. The release of silver ions from the resin bases was surveyed with inductively coupled plasma-mass spectroscopy (ICP-MS) every 24 hours.


RESULTS
The antimicrobial agent incorporated by ball-grinding method was even-distributed with individual particles of nanometer level in the PMMA resin base. The release of silver ions from the PMMA resin with antimicrobial agent was extremely slow during the test, a very small fraction of the silver ions released. At the beginning of the test, the release speed was extremely slow, the speed increased rapidly in the middle of the test, and at the end of the test, the speed returned to slow and steady. The cumulative release curve of silver ions was of "S" type.


CONCLUSIONS
STR-1 can be even-distributed in the denture base, and the silver ions release from the base with extremely slow speed. It also indicates that biological safety and long-term antimicrobial efficacy of denture base containing silver-supported antimicrobial agents of nanometer level are possibly obtained based on their slow release of silver ions.
Yu
Ri-yue
RY
Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China.
Zhou
Yong-sheng
YS
Feng
Hai-lan
HL
Liu
Xi-yun
XY
D000890:Anti-Infective Agents / Q000493:pharmacokinetics*; D003764:Dental Materials / Q000737:chemistry*; D003819:Denture Bases; D003829:Denture, Partial; D007477:Ions / Q000493:pharmacokinetics*; D008422:Materials Testing; D049329:Nanostructures; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012834:Silver / Q000493:pharmacokinetics*
D000890:Anti-Infective Agents; D003764:Dental Materials; D007477:Ions; D012834:Silver; D019904:Polymethyl Methacrylate