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Ruey-Song Chen

Publications and source records attributed to Ruey-Song Chen.

3 recordsLinked to original sources
PubMed2007

Effects on microstrain and conversion of flowable resin composite using different curing modes and units.

The flowable resin composite, Tetric Flow, was used to measure microstrain and degree of conversion after hardening with each of three curing machines: XL3000(XL) for 10, 20, 30, and 40 s; Optilux 501 using conventional mode (OC) for 10, 20, 30, and 40 s, as well as Optilux boost (OB, 10 s) and ramp modes (OR, 20 s); and LEDemetron (LEDe) for 10, 20, 30, and 40 s. The emitted power density and spectral distribution of the three light curing units were also measured. The LEDe output energy spectrum was centralized between 425 and 490 nm, which encompasses the excited wavelength of camphorquinone. The microstrain produced by the curing process is as a second-degree polynomial for each light source. The OB microstrain was highest, while the OR microstrain was lower. The ranking in order of degree of monomer conversion was as follows: XL10 <or=<or= OC10 <or=<or= LED 10 = OR = XL 20 = OC 20 = XL 30 <or=<or= LED 20 <or=<or= OC30 = LED 40 = XL 40 = OC40 = LED 30 <or= OB. The degree of conversion cured with OB was significant higher than other curing modes except OC30, OC40, LEDe30, LEDe40, and XL40. The conversion value of XL10 was the lowest. The LEDe produced higher conversion for the same emitted energy compared to the two halogen units.

Composite Resins↗
PubMed2003

Cytotoxicity of three dentin bonding agents on human dental pulp cells.

OBJECTIVES: Dentin bonding agents (DBA) have been widely used in operative restoration to prevent leakage and promote bonding strength in the resin-dentin interface. However, DBA may exert potentially harmful effects to the dental pulp. In the present study, differential cytotoxicity of three DBA (Syntac Sprint, SP; Prime and Bond 2.1, PB; and Single Bond, SB) on the pulp cells was tested. METHODS: Three DBA were diluted with the culture medium by a ratio of 1:1000, 1:2000 and 1:4000 (v/v). Pulp cells (5 x 10(4) cells/well) were then exposed to culture medium containing different diluents of three DBA for 12, 24h and 3 days. Cytotoxicity was measured with a modified 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. RESULTS: A 12h experiment revealed that SP was the strongest cytotoxic agent, followed sequentially by SB and PB. Exposure of pulp cells to 1:4000 (v/v) dilution of SP, PB and SB for 24h reduced the cell number by 23, 6 and 45%, respectively. A 1:2000 (v/v) of DBA diluents reduced the cell number for 32, 13 and 65%, respectively, by SP, PB and SB. Dilution of DBA by 1000-fold of culture medium further enhanced the cytotoxic response. Cell number decreased by 89, 65 and 72%, respectively, by SP, PB and SB. Similar to the 12h-cytotoxicity data, SB is more toxic at high dilution condition, whereas, at low dilution condition, SP is the most toxic agent to pulp cells. Similar cytotoxicity was noted when pulp cells were exposed to DBA for 3 days. Toxicity of DBA was concomitant with marked retraction and rounding of dental pulp cells. SIGNIFICANCE: These results indicate that DBA exerts potential harmful effects to the pulp. Differential toxic effects of DBA on the pulp cells should be considered during selection of a suitable DBA for operative restoration.

Acrylates↗