• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.33.1-33.12
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• 2023

Objectives: This study aimed to evaluate the bleaching efficacy and hydrogen peroxide permeability in the pulp chamber by the at-home bleaching gel in protocols applied on different dental surfaces. Materials and Methods: Forty premolars were randomly into 4 groups: control group no bleaching, only application on the buccal surface (OB), only application on the lingual surface (OL) and application in buccal and lingual surfaces, simultaneously (BL). At-home bleaching gel (White Class 7.5%) was used for the procedure. The bleaching efficacy was evaluated with a digital spectrophotometer (color change in CIELAB [ΔE_ab] and CIEDE 2000 [ΔE₀₀] systems and Whitening Index for Dentistry [ΔWI_D]). The hydrogen peroxide permeability in the pulp chamber (㎍/mL) was assessed using UV-Vis spectrophotometry and data were analyzed for a 1-way analysis of variance and Tukey's test (α = 0.05). Results: All groups submitted to bleaching procedure showed bleaching efficacy when measured with ΔE_ab and ΔE₀₀ (p > 0.05). Therefore, when analyzed by ΔWI_D, a higher bleaching efficacy were observed for the application on the groups OB and BL (p = 0.00003). Similar hydrogen peroxide permeability was found in the pulp chambers of the teeth undergoing different protocols (p > 0.05). Conclusions: The application of bleaching gel exclusively on the OB is sufficient to achieve bleaching efficacy, when compared to BL. Although the OL protocol demonstrated lower bleaching efficacy based on the ΔWI_D values, it may still be of interest and relevant in certain clinical scenarios based on individual needs, requiring clinical trials to better understand its specificities.

• Korean Journal of Dental Materials
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• v.43 no.1
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• pp.17-28
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• 2016

The aim of this study was to evaluate the changes in dentinal permeability after application of dentin desensitizer on exposed dentin immediately after ultrasonic scaling to teeth with non-carious cervical lesions. Thirty caries-free extracted molars were fixed to slide glasses after horizontally being sectioned at 5 mm below the cemento- enamel junction (CEJ). The prepared specimen was connected to a fluid flow measuring device (nano-Flow), and a V-shaped cavity was formed at the CEJ to imitate the non-carious cervical lesion. After no fluid leakage was confirmed in the connected system with specimen, tooth surface was treated ultrasonic cleaning with piezoelectric ultrasonic scalers until dentinal tubules were exposed. And 6 different desensitizers were applied on exposed dentin. Real-time measurements of dentinal fluid flow were performed during ultrasonic scaling and application of dentin desensitizer. To evaluate the occlusion of exposed dentinal tubules, tooth surface was examined by SEM. Following results were observed. After ultrasonic scaling, more dentinal tubules were exposed on the tooth with non-carious cervical lesions compared to tooth without lesions. The rate of fluid flow measured with nano-Flow system had correlation with the degree of dentin occlusion observed with SEM after application of desensitizers on exposed dentin. Desensitizers with glutaraldehyde and HEMA did not decrease the rate of fluid flow and did not show dentin occlusion. Desensitizers with oxalate showed the limited effects on the rate of fluid flow and dentinal tubule occlusion. Desensitizer with resin monomer showed the significant effect on the rate of fluid flow and dentin occlusion.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.165-176
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• 2014

Purpose: The effects of desensitizing agent are often for a short duration. One of the reasons is believed to be wear of desensitizing agent by tooth brushing. To reduce the wear and make the duration longer, dental bonding resin was applied and the changes of dentin permeability after toothbrushing were measured. Materials and methods: Extracted teeth free from caries were chosen. Coronal dentin discs with thickness of 1 mm were prepared. Using the split chamber device developed by Pashely, hydraulic conductance and scanning electron microscope images (SEM) were compared and contrasted before and immediately after the application of desensitizing agent and bonding resin and then after equivalent tooth brushing of 1 week, 2 weeks, and 6 weeks. Four commercially available desensitizing agents were used in this study; they were All-Bond 2, Seal & Protect, Gluma, and MS Coat. And Dentin/Enamel Bonding resin (Bisco Inc.) was used. The results of this study are as follows. Results: On all specimens, the hydraulic conductance decreased after the application of tooth desensitizing agent and bonding resin. Compared with the specimens treated only with desensitizer, the specimens treated with All-Bond 2, Gluma, MS Coat and plus D/E bonding resin had a little increase in hydraulic conductance after 1, 2 and 6-week tooth brushing. In case of Seal & Protect, the specimens showed the same result only after 6-week tooth brushing. On examination of SEM, the dentinal tubule diameter had decreased after treatment of desensitizing agents and bonding resin. And the specimens treated with All-Bond2, Seal&Protect, Gluma, MS Coat and plus D/E bonding resin had an significant decrease in diameter of dentinal tubule after 6-week tooth brushing. Conclusion: According to the results of this study, it is effective to use bonding resin after application of desensitizer in reducing the wear by tooth brushing and making the duration longer. In this study, just 6-week tooth brushing was performed, and it is not enough to regard it as a long-term data. So further study is needed and more perfect method for treating dentin hypersensitivity should be developed.