The Effect of Tooth Bleaching on Substance P Expression in Human Dental Pulp

doi:10.1016/j.joen.2008.09.013

Journal of Endodontics

Volume 34, Issue 12, December 2008, Pages 1462-1465

https://doi.org/10.1016/j.joen.2008.09.013 Get rights and content

Abstract

The purpose of this study was to quantify the effect of tooth bleaching on substance P (SP) expression in healthy human dental pulp. Forty pulp samples were obtained from healthy premolars in which extraction was indicated for orthodontic reasons. Thirty of these premolars were assigned into three different tooth-bleaching protocols: group 1 (n = 10): Opalescence Xtra Boost (Ultradent Products, South Jordan, UT) (38% H₂O₂) for 15 minutes; group 2 (n = 10): Lase Peroxide (DMC, Brazil) (35% H₂O₂) activated with infrared laser diode (Biolux; BioArt, Brazil) for 3 minutes, and group 3 (n = 10): Zoom! Whitening System (Discuss Dental, Culver City, CA) (25% H₂O₂) light activated for 20 minutes. The remaining 10 healthy premolars serve as a control group. Teeth were anesthetized immediately after bleaching and were extracted 10 minutes later. All pulp samples were processed and SP was measured by radioimmunoassay. Greater SP expression was found in the Zoom! Whitening System, followed by the Lase Peroxide group, Opalescence Xtra Boost, and the lower SP values were for the control group. Analysis of variance showed statistically significant differences between groups (p = 0.0001). Tukey HSD post hoc tests showed significant differences in the light (p < 0.01) and laser (p < 0.05) activated bleaching systems when compared with control values. It can be concluded that light- and laser-activated tooth-bleaching systems increase SP expression in human dental pulp significantly higher than normal values.

Section snippets

Materials and Methods

A descriptive comparative study was performed according to Colombian Ministry of Health recommendations regarding ethical issues in research involving human tissue. Written informed consent was obtained from each patient participating in the study. Forty pulp samples were obtained from healthy, nonsmoking human donors (18-27 years old) in whom healthy premolar extractions had been indicated for orthodontic purposes. All teeth used in this study were caries and restoration free with complete

Results

SP was found to be expressed in all pulp samples (Table 1). Highest SP levels were observed in experimental group III (Zoom! Whitening System). The mean expression for this group was 1649.52 ± 341.97 pmol SP/mg pulp tissue followed by experimental group II (Lase Peroxide activated with infrared laser diode) with a mean SP expression of 1054.66 ± 155.55 pmol SP/mg pulp tissue. The mean expression for the experimental group 1 (Opalescence Xtra Boost) was 760.23 ± 141.71 pmol SP/mg pulp tissue.

Discussion

Tooth bleaching is one of the most common procedures currently performed in contemporary dentistry. However, some controversy still exists on the safety of this procedure, showing numerous articles that defend bleaching as being innocuous to dental tissues, and, conversely, there is evidence in the literature that chemicals used for tooth bleaching have deleterious effects on pulpodentin complex (6, 7, 12, 19, 21, 22, 23, 24).

Enamel and dentin permeability allows these low–molecular-weight

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Cited by (90)

Temporospatial Expression of Neuropeptide Substance P in Dental Pulp Stem Cells During Odontoblastic Differentiation in Vitro and Reparative Dentinogenesis in Vivo
2023, Journal of Endodontics
Substance P (SP) is a neuropeptide released from the nervous fibers in response to injury. In addition to its association with pain and reactions to anxiety and stress, SP exerts various physiological functions by binding to the neurokinin-1 receptor (NK1R). However, the expression and role of SP in reparative dentinogenesis remain elusive. Here, we explored whether SP is involved in odontoblastic differentiation during reparative dentinogenesis.
Dental pulp stem cells (DPSCs) were isolated from healthy human dental pulp tissues and subjected to odontoblastic differentiation. The expression of SP and NK1R during odontoblastic differentiation was investigated in vitro. The effects of SP on odontoblastic differentiation of DPSCs were evaluated using alizarin red staining, alkaline phosphatase staining, and real-time polymerase chain reaction. After direct pulp capping with mineral trioxide aggregate, the expression of SP and NK1R during reparative dentin formation in rats were identified using histological and immunohistochemical staining.
SP and NK1R expression increased during the odontoblastic differentiation of DPSCs. SP translocated to the nucleus when DPSCs were exposed to differentiation medium. NK1R was always present in the nuclei of DPSCs and odontoblast-like cells. Additionally, we discovered that 10⁻⁸ M SP marginally enhanced the odontoblastic differentiation of DPSCs, and that these effects could be impaired by the NK1R antagonist. Furthermore, SP and NK1R were expressed in odontoblast-like and dental pulp cells during reparative dentin formation in vivo.
SP contributes to odontoblastic differentiation during reparative dentin formation by binding to the NK1R.
Effectiveness of Violet LED alone or in association with bleaching gel during dental photobleaching: A Systematic Review
2022, Photodiagnosis and Photodynamic Therapy
To conduct a systematic review to determine the efficacy of violet led in promoting dental bleaching by itself or accelerating dental bleaching when associated with peroxides.
Clinical and in vitro studies were identified by a search on November 27th 2020 in the PubMed and Scopus databases. Inclusion criteria were: 1) studies related to bleaching; 2) studies related to violet LED Light (405-410nm); and 3) studies that analyzed efficacy. The authors assessed the studies for risk of bias independently. Authors extracted outcomes including color change evaluation and pain assessment independently.
During the search process, 895 articles were found in the previously cited databases. After the first screening consisting of title and abstract evaluations, 18 articles were selected. Finally, 13 articles met the eligibility criteria and were included in this review, being 5 clinical trial/case series and 8 in vitro studies. In vitro studies showed a high risk of bias and interventional studies showed a low risk of bias.
The violet Led seems to have the potential to bleach teeth without peroxides, with a clinical perceptible color alteration. However, the effect is small in comparison to bleaching using peroxides. When Violet Led is used in association with peroxides, it seems to potentialize the bleaching result. However, due to the high heterogeneity between studies, a small number of clinical studies, and the high risk of bias of the in vitro included studies, the results are not definitive, and further well-designed studies are needed to reach safe evidence.
Influence of 35% hydrogen peroxide gel renewal on color change during in-office dental photobleaching with violet LED: A split-mouth randomized controlled clinical trial
2021, Photodiagnosis and Photodynamic Therapy
Citation Excerpt :
The products from the redox reaction of these bleaching gels result in reactive oxygen species (ROS) [6], which in part come in contact with the pulp tissue, causing oxidative stress. The painful process occurs by sensitization to nerve fibers, which may be mediated by the action of inflammation mediators [12]. Animal studies have reported a significant increase in the levels of pain-related neuropeptides (e.g. substance P and calcitonin gene-related peptide) [11].
To clinically evaluate the effect of 35% hydrogen peroxide gel renewal in association with violet LED (405-410nm) through a split-mouth randomized controlled clinical trial.
The treatment consisted in 3 bleaching sessions of 15 min each, with an interval of 7 days between them, using 35% hydrogen peroxide combined to violet LED irradiation. Selected patients had two experimental segments for the split-mouth design: No change of the bleaching gel during each session (NBGR) and 3 changes of the bleaching gel every 5 min for each session (BGR). During the 3 bleaching sessions, the selected quadrant received the same treatment. Patients had their upper canines and central incisors teeth color measured with a subjective (color scale - VITA Classical) and an objective (spectrophotometer - VITA Easyshade) method and their teeth sensitivity measured using a Visual Analog Scale (VAS) before, immediately after each bleaching session, and 14 days and 2 months (60 days) after the end of the treatment.
The protocol adopted in the present study reached satisfactory results regarding color change. No statistical difference between groups was observed immediately after the end of the treatment and in the follow-up analysis for both subjective and objective color evaluation. No difference in tooth sensitivity between segments was observed.
There is no need for bleaching gel renewal when following the clinical protocol of 3 sessions of 15 min in a bleaching protocol of 35% hydrogen peroxide combined with violet LED.
Prior Application of 10% Potassium Nitrate to Reduce Postbleaching Sensitivity: A Randomized Triple-Blind Clinical Trial
2020, Journal of Evidence-Based Dental Practice
To evaluate if the topical application of 10% potassium nitrate applied before in-office bleaching is effective to reduce the risk and intensity of tooth sensitivity (TS), as well as to evaluate if its application can jeopardize color change.
A randomized, split-mouth triple-blind clinical trial was conducted on 43 young patients with incisors A2 or darker. Half of the patient's upper arch received either the application of a 10% potassium nitrate or placebo gel for 10 min in a university setting. In-office bleaching was performed in three 15-min applications in two clinical sessions (1-week interval) using 35% hydrogen peroxide. Risk and intensity of TS was recorded with a 0-4 Numeric Rating Scale and a 0-10 Visual Analogue Scale during bleaching, 1 hour, 24 hours, and 48 hours after bleaching. Color was evaluated before and 1 month after bleaching with shade guides (Vita Classical and Vita Bleachedguide) and a spectrophotometer. The risk of TS (McNemar's test) and intensity of TS (Wilcoxon signed-rank for Numeric Rating Scale and paired t-test for Visual Analogue Scale) were statistically evaluated. Color change was compared using paired t-test. Significant level was set at 5%.
No significant difference was observed in the absolute risks of TS between groups (RR = 1.11; 95% CI 0.97 to 1.27; P = .12), which exceeded 87% for both groups. Similarly, no difference in TS intensities was detected (P > .05). Significant whitening was observed with all color measurement instruments with no difference between groups (P > .05).
The topical application of 10% potassium nitrate, before in-office bleaching, did not reduce the risk and intensity of TS and did not jeopardize color change.
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
2020, Photodiagnosis and Photodynamic Therapy
Citation Excerpt :
Moreover, these side effects may also result in decreased patient satisfaction after treatment. Several reports have provided explanations for the etiology of post-bleaching dental sensitivity, such as increased flow of dentinal fluid [6] with consequent mechanical excitation of the nerve fibers [7], as well as the oxidative effects of the treatment products on the pulp tissue [8]. When the bleaching gel comes in contact with the dental structures, reactive oxygen species (ROS) are released that diffuse through the dentinal tubules and reach the dentin-pulp complex [2,8–13], triggering an inflammatory process in these tissues [11,9–13].
To evaluate the bleaching efficacy and post-operative sensitivity of 10 % carbamide peroxide (PC) with or without violet LED (VL).
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.
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.
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.
Effect of anti-inflammatory and analgesic drugs for the prevention of bleaching-induced tooth sensitivity: A systematic review and meta-analysis
2019, Journal of the American Dental Association
Citation Excerpt :
Therefore, biochemical mediators, such as bradykinin, histamine, and prostaglandins, are synthetized and released, resulting in an inflammatory process. In fact, the increased pulpal expression of substance P (a peptide neurotransmitter) after dental bleaching indicates the inflammatory process plays an important role in postbleaching sensitivity.33 Several anti-inflammatory agents evaluated in the included studies act by means of inhibiting COX-2, which is an enzyme crucial to the production of prostaglandins and other inflammatory mediators.
In-office dental bleaching results in a high risk of tooth sensitivity caused by the inflammatory process of the pulpal tissue. In this systematic review, the authors aimed to evaluate the effect of administering anti-inflammatory and analgesic drugs for the prevention of tooth sensitivity associated with in-office dental bleaching.
The authors searched the databases MEDLINE via PubMed, Scopus, Web of Science, and Cochrane Library for clinical trials. They searched in ClinicalTrials.gov for unpublished trials. The authors included only randomized clinical trials comparing anti-inflammatory and analgesic drugs with a placebo and evaluating tooth sensitivity after in-office bleaching. They imposed no restrictions regarding publication dates or languages.
The authors identified 5,050 studies after the removal of duplicates. They qualitatively and quantitatively analyzed the 11 studies remaining after the title and abstract screening. Nine studies showed a low risk of bias. The authors found no effect of the drugs on the risk (9 studies evaluated this outcome). Using a visual analog scale, the authors identified a similar level of sensitivity evaluated up to 1 hour (10 studies evaluated this outcome) and 24 hours (8 studies evaluated this outcome). They observed similar results using the numeric rate scale (8 and 6 studies used this tool, up to 1 hour and 24 hours respectively). The Grading of Recommendations Assessment, Development, and Evaluation approach showed a high level of evidence for all outcomes.
The high level of evidence available does not support the administration of anti-inflammatory and analgesic drugs to prevent tooth sensitivity caused by in-office dental bleaching.

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Clinical researchThe Effect of Tooth Bleaching on Substance P Expression in Human Dental Pulp

Abstract

Section snippets

Materials and Methods

Results

Discussion

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

Dent Clin North Am

J Am Dent Assoc

J Am Dent Assoc

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

Oral Surg Oral Med Oral Pathol Oral Radiol Endod

J Endod

Clinical research
The Effect of Tooth Bleaching on Substance P Expression in Human Dental Pulp