Direct dentin bleaching: Would it be possible?

This study aims to evaluate in vitro the effect of violet LED when applied directly to dentin tissue pigmented by different substances. We analyzed the chromatic alteration, the bleaching effect and the temperature variation. Hence, 60 bovine dentin tissue discs were divided into five groups: NNatural Pigmentation; T-Black Tea; C-Soluble Coffee; W-Red Wine; B-Equine Blood. Individualized pigmentation protocols were performed and all groups reached the same chromatic change value. Subsequently, we simultaneously performed a bleaching session and measured temperature variation using a K-type thermocouple device. Data on chromatic change (∆E, ∆E00, ∆a, ∆b and ∆L), whitening effect (WID) and temperature variation were subjected to one-way Anova and Tukey's post-test at a 5% significance level. The C group showed the most relevant chromatic change values, similar to the N group, responding positively to the treatment. However, the B group differed from the control group, which showed difficulty to respond to the treatment. Regarding the whitening index, only the W group showed lower results than the others. The B group showed the greatest temperature changes. We conclude that the violet LED offered chromatic change, which generated a bleaching effect. Pigmentations with red wine and blood showed the greatest difficulty to respond to treatment, also promoting a higher temperature rise in teeth pigmented with blood.

Influence of violet LED associated or not with peroxide gel on inflammation, mineralization, and collagen fiber maturation in dentin and pulp tissue.

OBJECTIVES: To evaluate the influence of violet LED, associated or not with a 17.5% hydrogen peroxide (HP) bleaching gel, on inflammation, mineralization in pulp tissue, and collagen fiber maturation in dentin and pulp tissue. MATERIALS AND METHODS: The maxillary molars of eighty Wistar rats were distributed into four groups (n = 10): CONT - without treatment; HP - 30 min application of 17.5% HP; LED - 20 min application of violet LED; and HP+LED - application of PH and violet LED. Rats were euthanized and jaws were processed for histologic and immunohistochemical evaluation (IL-17, IL-23, and osteocalcin) and picrosirius red immediately after (T0), and at 7 (T1), 15 (T2), and 30 days (T3) post-treatment, with Wilcoxon, Mann-Whitney, paired T-test, and T-test (α = 0.05). RESULTS: HP and HP+LED presented necrosis and severe inflammatory infiltrate. When compared to CONT group, LED presented severe osteocalcin (OCN) immunostaining in T2 and less immature fibers in T2 and T3. CONCLUSION: The violet LED caused no severe damage to the pulp tissue, increased IL-17 and IL-23 expression in T0 when associated with HP, and had no influence on pulp tissue mineralization, besides accelerating the maturation of collagen fibers of dentin. CLINICAL RELEVANCE: Violet LED therapy induced no inflammation in the pulp tissue of rats and played no role in pulp tissue fibrosis, besides accelerating the maturation of dentin collagen fibers.

Influence of pain-relieving therapies on inflammation and the expression of proinflammatory neuropeptides after dental bleaching treatment.

OBJECTIVES: To minimize the tooth sensitivity caused by in-office bleaching, many dentists use non-steroidal anti-inflammatory drugs and topical desensitizing gels containing potassium nitrate and sodium fluoride. This study aimed to evaluate the influence of these substances on inflammation and the expression of substance P and calcitonin gene-related peptide in pulp nerve fibers. MATERIALS AND METHODS: Seventy-two rats were divided into 6 groups as follows: GI, control; GII, only dental bleaching; GIII, only ibuprofen; GIV, ibuprofen administered 30 minutes before and after the bleaching treatment and every 12 hours until the analysis; GV, only topical application of a desensitizing agent; and GVI, topical application of a desensitizing agent before dental bleaching. Placebo gel was applied to the upper left jaw and the bleaching agent was applied to the upper right jaw in all groups. Subsequently, the groups were divided into 3 subgroups based on the time of analysis: 0, 24, and 48 hours after bleaching (n = 8). The rats were euthanized and the maxillae were processed and evaluated by histopathological and immunohistochemical analyses. The data were analyzed using the Kruskal-Wallis test, followed by the Dunn test (p < 0.05). RESULTS: In the bleaching groups, the inflammatory process and expression of neuropeptides decreased over time. The animals in which a desensitizing agent was applied showed better results within 24 hours. CONCLUSIONS: The use of a desensitizing agent had positive effects on inflammation and pain-related neuropeptide expression, minimizing the painful effects of dental bleaching treatment.

Evaluation of the color change and tooth sensitivity in treatments that associate violet LED with carbamide peroxide 10 %: A randomized clinical trial of a split-mouth design.

BACKGROUND: To evaluate the bleaching efficacy and post-operative sensitivity of 10 % carbamide peroxide (PC) with or without violet LED (VL). METHODS: Thirty patients were selected and were instructed to perform home bleaching treatment using PC 10 %, for 8 h daily, for 21 days. All patients underwent in-office irradiation of only one hemiarch with VL for 30 min, twice per week for three weeks, totaling six clinical sessions of irradiation. The treatment used for each hemiarch was determined randomly. The analyses were performed at the initial time and 7, 14, and 21 days after the start of treatment and 7 and 14 days after the end of the bleaching treatment. For color analysis, digital spectrophotometry was done using the Visual Analog Scale and cold detection was performed using the thermo-sensory analysis II (TSA II) equipment. The ANOVA-two way with repeated measures and the Tukey test (α = 0.05) were used for the color and cold sensitivity analysis. RESULTS: On analyzing the color change, it was observed that the hemiarch that was irradiated with VL presented the highest values compared with the side that did not receive irradiation. Regarding tooth sensitivity, there was no report of any patient experiencing discomfort during the bleaching protocol. Analysis of the dental thermal sensation threshold showed that the use of VL made the teeth more sensitive. CONCLUSIONS: It can be concluded that the VL provided a positive effect on color alteration when used in conjunction with 10 % PC. However, the use of this new protocol made the teeth more sensitive.