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Preventive effect of potassium nitrate-glutaraldehyde gel in the bleaching-induced sensitivity
d e n t a l m a t e r i a l s 3 2 S ( 2 0 1 6 ) e1–e103
antimicrobial properties and increase the dentin bonding, without reducing mechanical properties.
Saturday
http://dx.doi.org/10.1016/j.dental.2016.08.111
Proteolytic activity of dentin caries-like lesions provided by smutans biofilm
111 Preventive effect of potassium nitrate-glutaraldehyde gel in the bleaching-induced sensitivity Reis ∗ ,
A. S. Parreiras, F.M. Coppla, E.C. Martini, A. Szesz, A.D. Loguercio Restorative Dentistry Department, State University of Ponta Grossa, Brazil Purpose/Aim: Although dental bleaching is one of the cosmetic treatments most requested by patients in dental offices, the in-office bleaching produces a high risk of bleachinginduced tooth sensitivity, which may affect more than 60% of the patients. In face of that, the aim of this randomized, split-mouth, triple-blind study was to evaluate the efficacy of a desensitizing gel based on 5% potassium nitrate and 5% glutaraldehyde applied before in-office bleaching with 35% hydrogen peroxide. Materials and methods: A total of 42 patients were included in the sample. Each side of the patient’s upper dental arch was randomly assigned to either the control group or experimental group. Before in-office bleaching with a 35 percent hydrogen peroxide gel (three applications of 15 min each), clinicians applied a placebo gel and the desensitizing agent (composed of 5% potassium nitrate; 2% sodium fluoride and 5% glutaraldehyde) to in the same manner in the respective randomized arch side. They repeated this protocol one week later. Patients recorded their tooth sensitivity on a 0-to-4 NRS scale and on a 0–10 VAS scale. Color change was evaluated with a spectrophotometer (Vita Easyshade) and two shade guide units (Vita classical and Vita Bleachguide 3D-Master). The risk of bleaching-induced tooth sensitivity of both groups was compared with the McNemar’s test and the color change was compared with the paired t-test (˛ = 5%). Results: The color change that occurred in both sides of the patient’s upper dental arch was statistically similar (p > 0.05) and occurred towards the lighter end of the shade guide units in all color scales and in the spectrophotometer. The risk of bleaching-induced tooth sensitivity in the control group was [31.7% (95% CI 19.6–46.9)] statistically lower (p < 0.0001) than that observed in the experimental group was [70.7 (95% CI 55.5–82.3%)]. Conclusions: It was concluded that the previous application of the experimental desensitizing agent based on 5% potassium nitrate and 5% glutaraldehyde before in-office bleaching reduced the risk and intensity of bleaching-induced tooth sensitivity without jeopardizing the bleaching effectiveness. http://dx.doi.org/10.1016/j.dental.2016.08.112
e55
112
J.P. De Sousa 1,∗ , L.F. Barbosa-Martins 1 , F.D. Nascimento 2 , R.M. Puppin-Rontani 1 1 2
FOP/University of Campinas, Brazil Universidade Anhanguera, Brazil
Purpose/Aim: Several methods have been developed to produce artificial caries lesions, since caries-affected dentin has being used in studies targeting restorative materials bonding to dentin. It has already known that natural caries lesions presents a substantial proteolytic activity by the activation of host matrix metaloproteinases (MMPs) in dentin, however, there is no information about enzymatic activity of dentin when submitted to artificial caries-like methods. Thus, this study evaluated the in situ proteolytic activity of dentin demineralized by an artificial biological caries model. Materials and methods: Fifteen coronal dentin specimens were randomly allocated into two groups: NC – natural caries (n = 3); and BM – dentin caries lesion produced by artificial biological model (12 teeth), which was divided into four subgroups (n = 3), according to the time of demineralization: BM3 – three, BM6 – six, BM12 – twelve and BM18 – eighteen days of demineralization. Dentin specimens from BM group were kept in sterile brain-heart infusion (BHI) broth supplemented with 0.5% yeast extract, 1% glucose, and 2% sucrose, where S. mutans (UA159) was inoculated with initial concentration of 0.05 at 550 nm (A550). Broth was renewed daily and, at each time point (3, 6, 12 and 18 days) three specimens were removed from the bacterial suspension (pH = 4.0). Dentin specimens from NC group were used as control. After demineralization, slices (200 m) of each specimen were prepared and carried to in situ Zymography, which was performed with quenched fluorescein-conjugated gelatin as the MMP substrate. Endogenous enzymatic activity was assessed by multi-photon confocal microscope. Polarized light microscopy confirmed the depth of dentin demineralization. Intensity of fluorescence was measured quantitatively and compared between BM groups (p < 0.05). Results: For all BM groups, it was observed higher green fluorescence in the zone corresponding to demineralized dentin than the underlying sound layer zone, indicating that the fluorescein conjugated gelatin was strongly hydrolyzed in the first zone, differently from natural caries group that presented green fluorescence in all extension of specimens. Intensity of fluorescence increased over time in demineralized zone (p < 0.01), whereas the fluorescence did not changed after six days in sound area (p > 0.05). Conclusions: Proteolytic activity of artificial caries-like lesions produced by biological model occurred predominantly in the zone where dentin had been demineralized, as result of release collagen bound-MMPs. http://dx.doi.org/10.1016/j.dental.2016.08.113
antimicrobial properties and increase the dentin bonding, without reducing mechanical properties.
Saturday
http://dx.doi.org/10.1016/j.dental.2016.08.111
Proteolytic activity of dentin caries-like lesions provided by smutans biofilm
111 Preventive effect of potassium nitrate-glutaraldehyde gel in the bleaching-induced sensitivity Reis ∗ ,
A. S. Parreiras, F.M. Coppla, E.C. Martini, A. Szesz, A.D. Loguercio Restorative Dentistry Department, State University of Ponta Grossa, Brazil Purpose/Aim: Although dental bleaching is one of the cosmetic treatments most requested by patients in dental offices, the in-office bleaching produces a high risk of bleachinginduced tooth sensitivity, which may affect more than 60% of the patients. In face of that, the aim of this randomized, split-mouth, triple-blind study was to evaluate the efficacy of a desensitizing gel based on 5% potassium nitrate and 5% glutaraldehyde applied before in-office bleaching with 35% hydrogen peroxide. Materials and methods: A total of 42 patients were included in the sample. Each side of the patient’s upper dental arch was randomly assigned to either the control group or experimental group. Before in-office bleaching with a 35 percent hydrogen peroxide gel (three applications of 15 min each), clinicians applied a placebo gel and the desensitizing agent (composed of 5% potassium nitrate; 2% sodium fluoride and 5% glutaraldehyde) to in the same manner in the respective randomized arch side. They repeated this protocol one week later. Patients recorded their tooth sensitivity on a 0-to-4 NRS scale and on a 0–10 VAS scale. Color change was evaluated with a spectrophotometer (Vita Easyshade) and two shade guide units (Vita classical and Vita Bleachguide 3D-Master). The risk of bleaching-induced tooth sensitivity of both groups was compared with the McNemar’s test and the color change was compared with the paired t-test (˛ = 5%). Results: The color change that occurred in both sides of the patient’s upper dental arch was statistically similar (p > 0.05) and occurred towards the lighter end of the shade guide units in all color scales and in the spectrophotometer. The risk of bleaching-induced tooth sensitivity in the control group was [31.7% (95% CI 19.6–46.9)] statistically lower (p < 0.0001) than that observed in the experimental group was [70.7 (95% CI 55.5–82.3%)]. Conclusions: It was concluded that the previous application of the experimental desensitizing agent based on 5% potassium nitrate and 5% glutaraldehyde before in-office bleaching reduced the risk and intensity of bleaching-induced tooth sensitivity without jeopardizing the bleaching effectiveness. http://dx.doi.org/10.1016/j.dental.2016.08.112
e55
112
J.P. De Sousa 1,∗ , L.F. Barbosa-Martins 1 , F.D. Nascimento 2 , R.M. Puppin-Rontani 1 1 2
FOP/University of Campinas, Brazil Universidade Anhanguera, Brazil
Purpose/Aim: Several methods have been developed to produce artificial caries lesions, since caries-affected dentin has being used in studies targeting restorative materials bonding to dentin. It has already known that natural caries lesions presents a substantial proteolytic activity by the activation of host matrix metaloproteinases (MMPs) in dentin, however, there is no information about enzymatic activity of dentin when submitted to artificial caries-like methods. Thus, this study evaluated the in situ proteolytic activity of dentin demineralized by an artificial biological caries model. Materials and methods: Fifteen coronal dentin specimens were randomly allocated into two groups: NC – natural caries (n = 3); and BM – dentin caries lesion produced by artificial biological model (12 teeth), which was divided into four subgroups (n = 3), according to the time of demineralization: BM3 – three, BM6 – six, BM12 – twelve and BM18 – eighteen days of demineralization. Dentin specimens from BM group were kept in sterile brain-heart infusion (BHI) broth supplemented with 0.5% yeast extract, 1% glucose, and 2% sucrose, where S. mutans (UA159) was inoculated with initial concentration of 0.05 at 550 nm (A550). Broth was renewed daily and, at each time point (3, 6, 12 and 18 days) three specimens were removed from the bacterial suspension (pH = 4.0). Dentin specimens from NC group were used as control. After demineralization, slices (200 m) of each specimen were prepared and carried to in situ Zymography, which was performed with quenched fluorescein-conjugated gelatin as the MMP substrate. Endogenous enzymatic activity was assessed by multi-photon confocal microscope. Polarized light microscopy confirmed the depth of dentin demineralization. Intensity of fluorescence was measured quantitatively and compared between BM groups (p < 0.05). Results: For all BM groups, it was observed higher green fluorescence in the zone corresponding to demineralized dentin than the underlying sound layer zone, indicating that the fluorescein conjugated gelatin was strongly hydrolyzed in the first zone, differently from natural caries group that presented green fluorescence in all extension of specimens. Intensity of fluorescence increased over time in demineralized zone (p < 0.01), whereas the fluorescence did not changed after six days in sound area (p > 0.05). Conclusions: Proteolytic activity of artificial caries-like lesions produced by biological model occurred predominantly in the zone where dentin had been demineralized, as result of release collagen bound-MMPs. http://dx.doi.org/10.1016/j.dental.2016.08.113