Evaluation of the color stability of light cured composite resins according to the resin matrices / 대한치과재료학회지

The purpose of this study was to evaluate the color stability of light cured composite resins according to the resin matrices. Three kinds of resin matrices such as Bis-GMA (Venus® Diamond; VD), Silorane (FiltekTM P90; P90), and Ormocer (Admira; Ad) were selected. Each of them were used to prepare 30 specimens. The initial CIE L*a*b* values were measured by means of a Spectrophotometer (NF999, Nippon Denshoku, Japan). For accelerated aging process, the specimens were immersed in a circulating water bath with distilled water at 60℃. Spectrophotometric analyses were made after immersion of 8, 16, 24, 41 days and the color difference (ΔE*) was calculated. The L* value increased compared with initial L* value. VD had the greatest L* value change and Ad had the smallest L* value change (p<0.05). Ad had the greatest a* value change and VD had the smallest a* value change (p<0.05). The b* value of P90 increased steadily in positive value (+)(p<0.05). ΔE* of Ad had the smallest value and that of P90 had the greatest change with time. According to this study, the value of light cured composite resins was increased with water sorption and color of those changed into greenish and yellowish. And according to the evaluation of color stability, Ad with Ormocer as resin matrices had the best color stability with time in oral environment and P90 with Silorane as resin matrices had the lowest color stability with time. And VD had the greatest initial ΔE*.

Effects of marginal adaptation with different materials on restoring dental wedge-shaped defects / 中国基层医药

Objective To evaluate the effects of marginal adaptation with different materials on restoring dental wedge-shaped defects. Methods From January 2016 to July 2016,80 patients with 172 wedge -shaped defect teeth in Stomatological Hospital of Haishu District were chosen and randomly divided into three groups accord-ing to random number table method,26 patients with 55 defect teeth were treated with Fuji glass ionomer( group A) , 23 patients with 59 defect teeth were treated with Carey charismatic light-cured composite resin( group B) ,and the other 31 patients with 58 defect teeth were treated with beautifil flow plus reinforced polymer F03(group C). Marginal adaptation of three groups of different materials of the teeth were measured. Results The micro -leakage depth among the three groups had statistically significant difference(H=7. 036,P=0. 035). The micro-leakage depth of group A,B and C were (1. 10 ± 0. 05) mm,(0. 96 ± 0. 05) mm,(0. 78 ± 0. 06) mm,respectively. There was statisti-cally significant difference among the three groups(F=22. 371,P=0. 005). Conclusion The marginal adaptation of beautifil flow plus reinforced polymer F03 is superior to FujiⅡglass-ionome and Charisma composite resin,and has benefits for treatment of wedge-shaped defects.

Clinic effect of SDR in restoring wedge-shaped defect / 实用口腔医学杂志

302 teeth with wedge-shaped defect in 168 patients were restored by SDR(smart dentin replacement,n =112),glass ionomer (n =98) and light-cured composite resin(n =92) respectively.12 to 15 month follow-up showed the success rate was 96.2％,84.8％ and 86.2％ respectively(P ＜ 0.01).SDR is an ideal material in restoring wedge-shaped defect.

Evaluation of compressive load required to fracture premolar restored with different restorative materials-an in vitro.

Background: Restored teeth are generally weaker than sound teeth due to loss of tooth structure caused by caries and restorative procedures. The loss of both tooth structures as a result treatment will increase the likelihood of fractures during functional loading. Objective: To evaluate the fracture resistance of premolars with class II disto occlusal preparations restored with light cured composite with light cured composites layered incrementally and silver amalgam in comparison with intact and unrestored teeth. Material and methods: 50 freshly extracted premolars were randomly divided into 5 groups of 10 teeth each. All the 50 specimens were then subjected to a compressive load in a Universal Testing Machine (Hounsfield). The loads required to fracture the teeth were recorded and the data, obtained were subjected to statistical analysis and the following results were arrived. Result: Teeth restored with light cured composite incrementally placed in oblique layers produced a higher fracture resistance than any other group and showed the closest value to the intact teeth. This was followed in descending order by light, cured composite placed in horizontal increments and silver amalgam. Conclusion: Result concluded that teeth restored with light cured composite incrementally placed in oblique layers produced a higher fracture resistance than any other group and showed the closest value to the intact teeth.

Effects of the color components of light-cured composite resin before and after polymerization on degree of conversion and flexural strength / 대한치과보존학회지

OBJECTIVES: This study investigated the effects of the color components of light-cured composite resin before and after polymerization on degree of conversion (DC) and biaxial flexural strength (FS). MATERIALS AND METHODS: Four enamel shades (A1, A2, A3, A4) and two dentin shades (A2O, A3O) of Premisa (Kerr Co.) and Denfil (Vericom Co.) were evaluated on their CIE L*, a*, b* color components using the spectrophotometer before curing, after curing and at 7 day. The DC of same specimens were measured with Near-infrared spectrometer (Nexus, Thermo Nicolet Co.) at 2 hr after cure and at 7 day. Finally, the FS was obtained after all the other measurements were completed at 7 day. The correlations between each color component and DC and FS were evaluated. RESULTS: The light-curing of composite resin resulted in color changes of Premisa in red-blue direction and Denfil in green-blue direction. The DC and FS were affected by product, time and shade (3-way ANOVA, p < 0.05) and product and shade (2-way ANOVA, p < 0.05), respectively. Premisa only showed a significant correlation between the DC and CIE a* component - before and after polymerization (Pearson product moment correlation, p < 0.05). The FS of Premisa showed significant negative correlations with CIE a* and CIE b* components. CONCLUSIONS: The DC and FS of the light-curing composite resin were affected by the color components of the material before and after polymerization.

Comparative enamel bond strength between light- and dual-cured composites bonded by self-etching adhesives / 대한치과보존학회지

This study compared the microshear bond strength (microSBS) of light-cured and dual-cured composites to enamel bonded with three self-etching adhesives. Crown segments of extracted human molars were cut mesiodistally, and 1 mm thickness of specimen was made. They were assigned to three groups by used adhesives: Xeno group (Xeno III), Adper group (Adper Prompt L-Pop), and AQ group (AQ Bond). Each adhesive was applied to cut enamel surface as per manufacturer's instruction. Light-cured (Filtek Z 250) or dual-cured composite (Luxacore) was bonded to enamel of each specimen using Tygon tube. After storage in distilled water for 24 hours, the bonded specimens were subjected to microSBS testing with a crosshead speed of 1 mm/minute. The mean microSBS (n = 20 for each group) was statistically compared using two-way ANOVA, Tukey HSD, and t test at the 0.05 probability level. The results of this study were as follows; 1. The microSBS of light-cured composite was significantly higher than that of dual-cured composite when same adhesive was applied to enamel. 2. For Z 250, the microSBS of AQ group (9.95 +/- 2.51 MPa) to enamel was significantly higher than that of Adper goup (6.74 +/- 1.80 MPa), but not significantly different with Xeno group (7.73 +/- 2.01 MPa). 3. For Luxacore, the microSBS of Xeno group (5.19 +/- 1.32 MPa) to enamel was significantly higher than that of Adper goup (3.41 +/- 1.19 MPa), but not significantly different with AQ group (4.50 +/- 0.96 MPa).

Effect of pH and storage time on the elution of residual monomers from polymerized composite resins / 대한치과보존학회지

OBJECTIVES: The purpose of this study was to determine whether pH and time has any influence on the degradation behavior of composite restoration by analyzing the leached monomers of dental composites qualitatively and quantitatively after storage in acetate buffer solution as a function of time using high performance liquid chromatography (HPLC) / mass spectrometer. MATERIALS AND METHODS: Three commercial composite restorative resin materials (Z-250, Heliomolar and Aeliteflo) with different matrix structure and filler composition were studied. Thirty specimens (7mm diameterx2mm thick) of each material were prepared. The cured materials were stored in acetate buffer solution at different pH (4, 7) for 1, 7 and 45days. As a reference, samples of unpolymerized composite materials of each product were treated with methanol (10 mg/ml). Identification of the various compounds was achieved by comparison of their mass spectra with those of reference compound, with literature data, and by their fragmentation patterns. Data were analysed statistically using ANOVA and Duncan's test. RESULTS: 1. Amounts of leached TEGDMA in Aeliteflo were significantly larger than those of UDMA in Z-250 and Heliomolar at experimental conditions of different storage time and pH variation (p 0.05).

Application of Artglass material in tooth aesthetical restoration / 中华医学美学美容杂志

Objective To explore the application of Artglass material in aesthetical restoration. Methods A total of 2196 restoratio ns, including 1963 veneers and 233 crowns, were made for 335 patients, and clini cal results were examined and recorded one by one. The related problems were dis cussed. Results There was significant improvement on cosmetics in most of the 2196 restorations; 44 restorations in 21 patients were failed, re sulting in a failure rate of 2%. The failure cases were repaired with Chrisma ma terial or remade with Artglass material. Conclusion Artglass ma terial has satisfactory prosthesis effects in aesthetical restoration. The bondi ng process and occlusion adjustment are important and should be specially notice d.