Introduction/Objective The aim was to evaluate initial efficiency of sodium perborate (tetrahydrate) and 30% hydrogen peroxide mixture for intracoronal non-vital teeth bleaching ("walking bleach" technique). Methods Forty patients with discolored teeth were included in the study. Based on their history and clinical examination, causes of discoloration were classified as necrotic pulp, "endo-sealer" or unknown. The "walking bleach" technique was performed by applying sodium perborate (tetrahydrate) and 30% hydrogen peroxide mixture intracoronally to cavity dentin walls. The mixture was renewed in seven-day intervals. Tooth color was assessed visually before, during, and after the procedure using the Vita Classical shade guide (Vita Zahnfabrik, Bad Säckingen, Germany). Numerical values or shade guide units (SGU) were assigned to Vita shade tabs on a bright-dark scale. Analysis of variance, t-test, correlation and regression analysis were used to analyze the data (p < 0.05). Results On average, 26 ± 9 days or 3-4 appointments were required for intracoronal bleaching to achieve the desired or best possible shade. Better clinical efficiency was found in the necrotic pulp group (17 ± 6 days; 8 ± 3 SGU) than in the "endo-sealer" group (42 ± 13 days; 4 ± 2 SGU) (p < 0.05). Age significantly influenced bleaching efficiency (p < 0.05). There was no significant correlation between bleaching efficiency and initial shade (p > 0.05). Conclusion Intracoronal, non-vital teeth bleaching ("walking bleach" technique) using sodium perborate (tetrahydrate) and 30% hydrogen peroxide mixture showed satisfactory clinical efficiency. Discoloration caused by pulp necrosis was treated more efficiently than that caused by endodontic sealers. Younger age had a positive effect and discoloration intensity had no effect on bleaching efficiency.

The objective of this study was to measure temperature changes in the pulp chamber induced by polymerization of resin-based dental restoratives following a simulated procedure of direct pulp capping. Class I cavities with a microperforation at the pulp horn were prepared in extracted human molar teeth. The complete procedure of direct pulp capping and cavity restoration was performed with the root part of extracted teeth fixed in a water bath at 37 °C. Mineral trioxide aggregate, bioactive dentin substitute or calciumhydroxide paste were used as pulp capping materials. Cavities were restored with a lightcured or chemically-cured resin-modified glass ionomer, universal adhesive and a bulk-fill composite, cured with a high-intensity LED unit. Pulp capping materials caused a slight temperature decrease. Lower temperature increase was recorded during light-curing of the glass ionomer liner after direct capping with mineral trioxide aggregate and calciumhydroxide than that recorded for the bioactive dentin substitute. Adhesive light-curing increased temperature in all groups with higher mean temperatures in groups with chemically-cured as compared to those for the light-cured glass ionomer liner. Direct pulp capping with mineral trioxide aggregate or calcium-hydroxide followed by the light-cured resin-modified glass ionomer liner and a bonded bulk-fill composite restoration induced temperature changes below the potentially adverse threshold of 42.5 °C.