• Restorative Dentistry and Endodontics
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• v.47 no.1
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• pp.7.1-7.14
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• 2022

Objectives: This study evaluated the bleaching efficacy of different in-office protocols associated with violet light emitting diode (V-LED), and measured the pulpal temperature rise caused by V-LED with or without gel application. Materials and Methods: Bovine incisors were distributed in 4 groups (n = 10): VL - V-LED; HP - 35% hydrogen peroxide (control); HYB - hybrid protocol, V-LED applied without gel for 10 irradiation cycles followed by V-LED applied with gel for another 10 irradiation cycles; and HPVL - gel and V-LED applied for 20 irradiation cycles. Three bleaching sessions were performed with 7-day intervals. Bleaching efficacy was evaluated with ΔE_ab^*, ΔE₀₀ and ΔWI_D. Data were recorded at baseline, 7, 14, 21 and 70 days. For pulpal temperature rise, thermocouples were placed inside the pulp chamber of human incisors. To determine intrapulpal temperature, the teeth were irradiated with V-LED with or without application of bleaching gel. Color difference data were analyzed by 2-way repeated measures ANOVA and Tukey's test. Pulpal temperature was analyzed by t-test (α = 5%). Results: VL exhibited lower color (ΔE_ab^* and ΔE₀₀) and whiteness changes (ΔWI_D) than the other groups. HPVL presented higher color change values than HYB. HYB and HPVL showed not different ΔWI_D values; and HP showed the highest whiteness changes at all times. There were significant differences comparing ΔT with gel (8.9℃) and without gel application (7.2℃). Conclusions: HPLV was more efficient than HYB. The 2 protocols with VL showed similar results to control. Gel application combined with VL promoted higher pulpal temperature than to the no gel group.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.198-210
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• 2010

This study evaluated the safety of an office bleaching gel (RemeWhite, Remedent Inc., Deurle, Belgium) containing 30% hydrogen peroxide. 37 volunteers were received office bleaching with the RemeWhite for 3 times at one visit, total 2 visits. As control group, the same gel in which hydrogen peroxide was not included was applied to 34 volunteers with the same protocol. There was no difference between experimental group and control group using electric pulp test. In the result of gingival inflammation index and tooth sensitivity test, there was mild pain response in experimental group but it disappeared as time went by. Therefore, safety of the office bleaching gel containing 30% hydrogen peroxide was confirmed.

• Restorative Dentistry and Endodontics
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• v.48 no.2
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• pp.12.1-12.11
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• 2023

Objectives: The present study evaluated the pulp response of human mandibular incisors subjected to in-office dental bleaching using gels with medium or high concentrations of hydrogen peroxide (HP). Materials and Methods: The following groups were compared: 35% HP (HP35; n = 5) or 20% HP (HP20; n = 4). In the control group (CONT; n = 2), no dental bleaching was performed. The color change (CC) was registered at baseline and after 2 days using the Vita Classical shade guide. Tooth sensitivity (TS) was also recorded for 2 days post-bleaching. The teeth were extracted 2 days after the clinical procedure and subjected to histological analysis. The CC and overall scores for histological evaluation were evaluated by the Kruskal-Wallis and Mann-Whitney tests. The percentage of patients with TS was evaluated by the Fisher exact test (α = 0.05). Results: The CC and TS of the HP35 group were significantly higher than those of the CONT group (p < 0.05) and the HP20 group showed an intermediate response, without significant differences from either the HP35 or CONT group (p > 0.05). In both experimental groups, the coronal pulp tissue exhibited partial necrosis associated with tertiary dentin deposition. Overall, the subjacent pulp tissue exhibited a mild inflammatory response. Conclusions: In-office bleaching therapies using bleaching gels with 20% or 35% HP caused similar pulp damage to the mandibular incisors, characterized by partial necrosis, tertiary dentin deposition, and mild inflammation.

• Restorative Dentistry and Endodontics
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• v.41 no.3
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• pp.196-201
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• 2016

Objectives: The aim of this in vitro study was to evaluate the effect of incorporating three different nanobiomaterials into bleaching material on microhardness of bleached enamel. Materials and Methods: The crowns of 24 extracted sound human molars were sectioned. Sixty enamel specimens ($2{\times}3{\times}4 mm$) were selected and divided into five groups (n = 12): Group 1 received no bleaching procedure (control); Group 2 underwent bleaching with a 40% hydrogen peroxide (HP) gel; Groups 3, 4, and 5 were bleached with a 40% HP gel modified by incorporation of bioactive glass (BAG), amorphous calcium phosphate (ACP) and hydroxyapatite (HA), respectively. The enamel microhardness was evaluated. The differences in Knoop microhardness data of each group were analyzed by one-way ANOVA, followed by post hoc Tukey tests. Results: Significant differences were observed between the study groups. The enamel microhardness changes in Groups 1, 3, 4, and 5 were significantly lower than that of Group 2 (p < 0.001). Conclusions: Within the limitations of this study, it can be concluded that incorporation of each one of the three tested biomaterials as remineralizing agents might be effective in decreasing enamel microhardness changes subsequent to in-office bleaching.

• Restorative Dentistry and Endodontics
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• v.35 no.1
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• pp.40-50
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• 2010

This study evaluated the efficacy of an office bleaching gel (RemeWhite, Remedent Inc., Deurle, Belgium) containing 30% hydrogen peroxide. 31 volunteers were recieved office bleaching with the RemeWhite for 3 times at one visit, total 2 visits. As control group, the same gel in which hydrogen peroxide was not included was applied to 31 volunteers with the same protocol. The shade change (${\Delta}E^*$, color difference) of 12 anterior teeth was measured using Colorimerter and Vitapan classical shade guide. The shade change of overall teeth in the experimental group was significantly greater than that in the control group which was measured using Colorimeter. There was also a significant difference between baseline and 14 weeks or 26 weeks though color rebounding phenomenon occurred as time went by. Small shade change difference can be measured accurately using Colorimeter than using Vitapan classical shade guide.

• Restorative Dentistry and Endodontics
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• v.33 no.5
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• pp.463-471
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• 2008

This study investigated the clinical effectiveness and safety of sealed bleaching compared to conventional in-office bleaching using a randomized clinical trial of split arch design. Ten participants received a chairside bleaching treatment on the upper anterior teeth, and each side was randomly designated as sealed or control side. A mixture of Brite powder (PacDent, Walnut, USA), 3% hydrogen peroxide and carbamide peroxide (KoolWhite, PacDent, Walnut, USA) were used as bleaching agent. The control side was unwrapped and the experimental side was covered with a linear low density polyethylene (LLDPE) wrap for sealed bleaching. The bleaching gel was light activated for 1 hour. The tooth shades were evaluated before treatment, after treatment, and at one week check up by means of a visual shade (VS) assessment using a value oriented shade guide and a computer assisted shade assessment using a spectrophotometer (SP). The data were analyzed by paired t-test. In the control and sealed groups, the visual shade scores after bleaching treatment and at check up showed statistically significant difference from the preoperative shade scores (p<.05). The shade scores of the sealed group were significantly lighter than the control immediately after bleaching and at the check-up appointment (p<0.05). Compared to prebleaching status, the ${\Delta}E$ values at post bleaching condition were $4.35{\pm}1.38\;and\;5.08{\pm}1.34$ for the control and sealed groups, respectively. The ${\Delta}E$ values at check up were $3.73{\pm}1.95\;and\;4.38{\pm}2.08$ for the control and sealed groups. ${\Delta}E$ values were greater for the sealed group both after bleaching (p<.05) and at check up (p<.05). In conclusion, both ${\Delta}E$ and shade score changes were greater for the sealed bleaching group than the conventional bleaching group, effectively demonstrating the improvement of effectiveness through sealing.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.20.1-20.14
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• 2020

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.

• Restorative Dentistry and Endodontics
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• v.36 no.4
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• pp.306-312
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• 2011

Objectives: This clinical study evaluated the effect of light activation on the whitening efficacy and safety of in-office bleaching system containing 15% hydrogen peroxide gel. Materials and Methods: Thirty-three volunteers were randomly treated with (n = 17, experimental group) or without light activation (n = 16, control group), using Zoom2 white gel (15% $H_2O_2$, Discus Dental) for a total treatment time of 45 min. Visual and instrumental color measurements were obtained using Vitapan Classical shade guide and Shadepilot (DeguDent) at screening test, after bleaching, and 1 month and 3 month after bleaching. Data were analyzed using t-test, repeated measure ANOVA, and chi-squared test. Results: Zoom2 white gel produced significant shade changes in both experimental and control group when pre-treatment shade was compared with that after bleaching. However, shade difference between two groups was not statistically significant (p > 0.05). Tooth shade relapse was not detected at 3 months after bleaching. The incidence of transient tooth sensitivity was 39.4%, with being no differences between two groups. Conclusions: The application of light activation with Zoom2 white gel system neither achieved additional whitening effects nor showed more detrimental influences.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.24-29
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• 2004

Alkaline cellulolytic enzymes from cultured medium of Coprinus cinereus 2249 were purified with gel and ion-exchange chromatography and characteristics of those enzyme proteins were investigated. A fiber length distribution and a crystallinity of cellulose and sugar composition of enzyme treated Mixed Office Wastepaper(MOW) and Unbleached Kraft Pulp(UKP) were analysed. The conclusion could summarized as follows; \circled1 Alkaline and acidic, endo- and exo-glucanases were purified from cultured medium of Coprinus cinereus 2249. \circled2 The approximate molecular weight of alkaline endo-glucanase was 42 kDa, and also that of alkaline exo-glucanase was 50 kDa. A fiber length distribution and a crystallization of cellulose and sugar composition of enzyme treated MOW and UKP were not so much changed with original paper and pulp.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.3
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• pp.257-265
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• 2009

Statement of problem & Purpose: To study the effect of different fluoridation methods after in-office bleaching on the color of teeth during severe staining with coffee. Material and methods: 44 specimens were randomly divided into four groups. Group 1 (no bleaching, no fluoride, coffee) was served as control for the influence of coffee on the color of untreated teeth. Group 2, 3 and 4 were undergone bleaching with 35% $H_2O_2$ for 30 minutes a day on 3 consecutive days. Group 2 was remained without fluoridation. Group 3 and 4 were fluoridated for 1 hour with either Cavity shield$^{(R)}$ or pH 7 Gel$^{(R)}$. All of groups were immersed in coffee solution for 7 days. Color determination was accomplished using the spectrophotometer (VITA Easyshade$^{(R)}$). Results: ${\Delta}L$ and ${\Delta}h$ increased, whereas ${\Delta}C$ decreased in the bleached groups. Pairwise comparisons with Tukey's HSD showed that there were statistically significant differences for ${\Delta}L$ and ${\Delta}h$ between the bleached groups and the non-bleached group (P < .05). ${\Delta}L$ and ${\Delta}h$ decreased continuously, while ${\Delta}C$ showed an increase after a decrease in all of groups during immersion in coffee solution. After immersion in coffee solution for 7 days there were no statistically significant differences for ${\Delta}L$, ${\Delta}C$ and ${\Delta}h$ between the groups (P > .05). Also there were no statistically significant differences for ${\Delta}L$, ${\Delta}C$ and ${\Delta}h$ between the group 3 treated with Cavity shield. and the group 4 treated with pH 7 Gel. (P > .05). Conclusion: It was concluded that fluoridation was not beneficial to the prevention of extrinsic stains after bleaching.