[Impact assessment on enamel remineralization after orthodontic treatment with casein phosphopeptide calcium phosphate complex].

PURPOSE: To compare the effect on enamel demineralization following fluoride rinse or casein phosphopeptide calcium phosphate complex (CPP-ACP) after fixed appliance orthodontic treatment. METHODS: The study population consisted of 21 post-orthodontic patients (13 females, 8 males, 84 affected teeth) with white spot lesions (WSL). They were divided into 3 groups with 28 affected teeth in each group. Participants in the control group were brushed with fluoride toothpaste twice a day. Participants in the fluoride group were instructed to rinse the mouth with 20mL 0.01% sodium fluoride rinse in addition to brushing twice a day. Participants in CPP-ACP group were instructed to use tooth moss after brushing their teeth twice a day for 6 months. SPSS 17.0 software package was used to analyze the data. RESULTS: Within 6 months after orthodontic treatment, white spot lesions areas of the three groups caused by enamel demineralization were all reduced in different degrees, and the differences of success rate were significant among three groups (P<0.05). CPP-ACP group achieved the highest success rate (51%) than the other group, the fluoride group (44%) and the control group (42%). CONCLUSIONS: Brushing teeth, fluoride rinse and CPP-ACP have certain effect on remineralization of demineralized teeth in 6 months after orthodontic treatment. Compared with brushing and fluoride rinse, CPP-ACP can reduce the area of enamel demineralization more effectively.

The influence of resin cements on the final color of ceramic veneers.

PURPOSE: To evaluate the effect of three brands of resin cement on the final color of ceramic veneers. METHODS: 50 disk-shaped ceramic specimens (IPS e.Max, 0.6mm×8.0mm diameter) and disk-shaped composite resin background specimens (4.0mm×8.0mm diameter) were prepared and divided into 10 groups (n=5). These paired specimens were bonded using ten shades of resin cement (Variolink Veneer, shades LV-3, LV-2, MV, HV+2, HV+3; Panavia F, shades light and brown; and RelyX™ Veneer, shades WO, TR, A3). A spectrophotometer (VITA Easyshade) was used to measure the color parameters (CIE L*a*b* values) of the paired disks before and after cementation. The color differences (ΔE values) after cementation were calculated and statistically analyzed by the One-way ANOVA (at the significant level p<0.05). RESULTS: The color parameters of the ceramic disks were measured in terms of the increase in L* value, and the decrease in Cab(*) value after bonding with the resin cement. The ΔE values of ceramic disks after cementation ranged from 1.38 to 7.16. The ΔE values were more than 3.3 when the ceramic disks were cemented with resin cements in shade HV+3 (4.90) and shade WO (7.16). One-way ANOVA of ΔE values revealed significant differences in the resin cement shades. CONCLUSIONS: Resin cements can affect the final color of ceramic veneer restorations, and the extent of this effect varies according to the resin cement shades.

[Effect of the shade and thickness of luting agent on the color of solidex resin].

OBJECTIVE: To evaluate the effect of the shade and thickenss of luting agent on the final color of different thickness Solidex resin in vitro. METHODS: Five specimens of Solidex resin were fabricated at thickness of 0.5, 1.0 and 1.5 mm. The pieces of Ni-Cr alloy, two shade composite resin and opaque porcelain veneered Ni-Cr alloy were used as backgrounds. The CIE L*a*b* values of specimens were measured by a colorimeter (ShadeEye NCC) to determine the colorimetric difference, when different thickness of specimens were overlaid the different shade and thickness of luting agent at the same backgrounds. RESULTS: The final color difference of specimens was significantly influenced by the factors of luting agent and the interaction of specimens thickness, backgrounds and luting agent(P< 0.001). Regarding the thickness of luting agent, A3 shade luting agents produced clinically unacceptable difference (deltaE*>2) in the final color of Solidex specimens at the thickness of 0.5 mm. Regarding the shade of luting agent, the color difference was more than 2 when the Solidex specimens at the thickness of 0.5 mm or 1.0 mm were against the 0.2 mm thick luting agent. CONCLUSION: The final color of thinner Solidex specimens was significant affected by the change of the shade and thick of luting agent.

[Effect of three backgrounds on the final color of Solidex with six different thickness].

OBJECTIVE: To analyze the final color of Solidex in six thickness interacting with three different backgrounds. METHODS: Five specimens of Solidex in each shade A1, A3, and C2 were fabricated at thickness of 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0 mm. The CIE L(*)a(*)b(*) values of specimens were measured using a colorimeter (ShadeEye NCC) to determine the colorimetric difference, when the specimens overlaid on different backgrounds. RESULTS: When the thickness was more than 1.8 mm, the color difference (DeltaE(*)ab < 1) was not perceived by human observers. When the thickness was 1.4 mm or less than 1.4 mm, the color difference (DeltaE(*)ab > 2.72) was considered clinically unacceptable between alloy background and two types of composite resin background. CONCLUSIONS: Alloy background had more evident influence on the final color of Solidex than composite resin background. When making metal-free crown restoration using Solidex, it was advisable to make the composite resin more than 1.8 mm thick.