Direct Radiotherapy-Induced Effects on Dental Hard Tissue in Combination With Bleaching Procedure

Introduction: The aim of this study was to evaluate the effects of radiation and tooth bleaching on the physical and morphological properties of enamel and dentin on permanent teeth.Materials and Methods: Eighty fresh, non-carious third molars were used in this study. Before cutting the crown in half, the teeth samples were randomly allocated to treatment and control groups by using a lottery method. The first group (n = 20) underwent standard radiation protocol (2 Gy/fraction/day, 5 days/week) with bleaching treatment afterward using 16% carbamide peroxide gel, the second group (n = 20) underwent standard radiation protocol with afterward bleaching treatment using 38% hydrogen peroxide, the third group (n = 20) underwent a short, one strong, experimental dose of 70 Gy with afterward bleaching treatment using 16% carbamide peroxide gel, and the fourth group (n = 20) underwent one strong, experimental dose of 70 Gy with afterward bleaching treatment using 38% hydrogen peroxide gel. Groups 5–8 (n = 20) served as control as they underwent only bleaching treatment. Vickers microhardness and surface roughness were performed before (initial) and after irradiation and before bleaching or after only bleaching. The effects of irradiation and bleaching on microhardness (or roughness) of enamel and dentin were analyzed in the repeated-measures ANOVA model.Results: Enamel microhardness after experimental single 70-Gy irradiation or after standard radiation protocol and bleaching with 16 or 38% gel was not statistically significant from microhardness in the control group (p > 0.05). There was a statistically significantly greater reduction in the average microhardness of enamel and dentin during bleaching with 38% gel compared to 16% for both radiation protocols (p < 0.001). After experimental 70-Gy irradiation and bleaching, a 16% statistically significant increase in surface roughness was found for enamel (p = 0.006) and dentin (p = 0.018), while this was not recorded for 38% gel. There was a statistically significantly greater increase in the average roughness of enamel and dentin during bleaching with 38% gel compared to 16% (p < 0.001) for both radiation protocols.Conclusions: Directly induced radiation leads to potential damage of hard dental tissues, which can be further damaged by additional bleaching. If teeth whitening is necessary after irradiation, it is suggested to use lower concentrations of whitening gels.

Raman spectroscopy analysis of dental enamel organic and mineral composition: an experimental non-randomised study

Background. Contemporary dental diagnosis should supplement clinical examination with instrumental diagnostic techniques. Raman spectroscopy has become widely adopted due to high spatial resolution, non-invasiveness, the lack of strict requirements and ease of sample preparation.Objectives. A qualitative assessment of enamel mineral and organic composition dynamics using Raman spectroscopy.Methods. Raman spectroscopy was used as primary research method. The trial bench consisted of a Shamrocksr-303i high-resolution digital spectrometer with built-in DV420A-OE cooled optical detector (spectral range 200–1200 nm), RPB-785 optic fibre scattering probe integrated with LuxxMaster LML-785.0RB-04 laser source with wavelength 785 nm.Software spectrum processing was performed with Wolfram Mathematica 9. Spectra were denoised with a median filter (5 points), the approximating line (fifth order polynomial) of autofluorescent component was determined in 700–2200 cm-1 range using an iterative algorithm and then subtracted to receive isolated Raman spectra.Linear discriminant analysis (LDA) of data was performed with the IBM SPSS Statistics package. Results. The assay included 28 teeth, with 14 extracted for orthodontic indications and 14 — for chronic periodontitis. Spectral dental enamel dynamics has been established in periodontal disease and after the in-office bleaching procedure. The evidence obtained can be applicable in dental practice to verify patients at risk of periodontal disease by interpreting the tooth enamel spectral properties, as well as prior to in-office bleaching.Conclusion. We demonstrate high efficiency of Raman spectroscopy for qualitative assessment of the mineral and organic enamel composition dynamics in various settings. Raman spectroscopy is confirmed effective and versatile in various aetiologies. It was successfully applied to diagnose periodontitis by changes in the organic and mineral enamel composition and evaluate enamel after in-office bleaching.

Pomegranate (Punica granatum L.) gel extract as an antioxidant on the shear bond strength of a resin composite post-bleaching application with 40% hydrogen peroxide

Background: Tooth discoloration can be treated with tooth bleaching. Bleaching using 40% hydrogen peroxide can reduce the shear bond strength of resin composite because there are free radicals on the tooth surface, so it can delay the restoration. The application of antioxidants can eliminate free radicals after the bleaching procedure and increase the shear bond strength of the composite resin. The common antioxidants are ascorbic acid and natural ingredients, such as pomegranate (Punica granatum L.). Purpose: To determine the effect of pomegranate extract gel on the shear bond strength of composite resin after 40% hydrogen peroxide bleaching application. Methods: This research used 32 maxillary first premolars that were divided into four groups. The samples were bleached, then the labial was prepared and antioxidant gel was applied: group P1 pomegranate gel extract of 5%, group P2 pomegranate gel extract of 10%, group K1 positive control ascorbic acid gel of 10% and group K2 as the negative control. The samples were restored with a nanohybrid composite resin. The shear bond strength was tested using a universal testing machine. The data were tested using a one-way ANOVA followed by a post-hoc LSD test. Results: The pomegranate gel extract increased the shear bond strength of the composite resin after the bleaching procedure of 40% hydrogen peroxide compared with the ascorbic acid gel group and the negative control group. The one-way ANOVA test showed a significant difference (p<0.05). The post-hoc LSD test showed significant differences between the treatment and negative control groups (p<0.05). Conclusion: The pomegranate gel extract as an antioxidant increased the shear bond strength of the composite resin restoration after the 40% hydrogen peroxide bleaching application.

A comparative analysis of in-office vital 6% hydrogen peroxide activated charcoal tooth whitening treatment enhanced with an 810nm diode laser, compared to 35% hydrogen peroxide bleaching

Laser dental bleaching is considered to be a contemporary approach to enhancing the in-office power bleaching procedure. Objective Investigate if laser enhanced 6% Hydrogen Peroxide (HP) solution is equivalent to 35% HP solution over a two-visit power bleaching treatment protocol. In a randomised double-blinded clinical trial, 43 patients were assigned to a group that received either the laser-enhanced 6% Hydrogen Peroxide (n=21) treatment, or the standard 35% Hydrogen Peroxide (n=22) treatment, over two visits, with a one-week interval. Activated charcoal HP paste was prepared for both groups. The laser enhanced 6% HP group received a dosage of 90 J/cm² per bleaching cycle using 810nm diode laser. Tooth colour was measured at the beginning and end of each session registering parameters L*, a* and b*, and tooth sensitivity. The calculated difference between these Parameters, ∆E, was the primary data focus. The mean ∆E over the treatment duration was used to answer the research question by a t-test to evaluate group differences at 5% significance level. The analysis revealed that the null hypothesis could not be rejected and the results were inconclusive. The observations expound the idea of an absorption enhancement mechanism, rather than a free radical activation, as the technique for improving bleaching outcomes.

Elemental and morphological analysis of enamel following the application of two bleaching systems with amorphous calcium phosphate: effect on enamel erosion susceptibility

Background Using remineralizing agents during and after bleaching procedures could maintain enamel surface, decreasing its erosive susceptibility. This study evaluated the efficacy of an in-office and at-home bleaching materials with amorphous calcium phosphate (ACP) on the susceptibility of the enamel to erosion. Forty-five bovine specimens were separated into three groups. Group A: no bleaching (control). Group B: Zoom 2 bleaching followed by ACP application. Group C: Nite White ACP. All specimens in all groups were subjected to an erosive challenge for five days. Using Energy Dispersive X-ray all specimens were subjected to elemental analysis and were examined for morphological changes under Scanning Electron Microscope (SEM). Results Group B showed the highest mean calcium, phosphorus and sodium weight percent (wt%). Both Groups B and C showed statistically significant difference. While, there was no statistically significant difference between both Groups A and B.The sodium mean wt% showed a statistically significant difference in all groups. The magnesium mean wt% showed no statistically significant difference in all groups. SEM photomicrograph revealed hollowing of prism cores with intact prisms peripheries for group A. Group B showed relativity smooth surface with minor pores, while Group C showed an increase in the depth of surface irregularities and depressions. Conclusions Enamel susceptibility to erosion after bleaching procedure was material dependent. Zoom 2 bleaching agent followed by ACP application did not increase the susceptibility of the enamel surface to erosion. Adding ACP to Nite White bleaching agent had no benefit on reducing enamel susceptibility to erosion.

Penatalaksanaan diskolorisasi gigi pasca perawatan endodontik dengan teknik walking bleachManagement of post-endodontic tooth discolouration with the walking bleach technique

Pendahuluan: Diskolorisasi gigi setelah perawatan endodontik dapat disebabkan oleh bahan pengisi saluran akar. Bahan endodontik yang tertinggal di dalam kamar pulpa akan menginfiltrasi tubulus dentin sehingga menyebabkan pewarnaan. Diskolorisasi intrinsik akibat bahan pengisi saluran akar seringkali terlihat pada sepertiga servikal gigi yang telah dirawat endodontik. Walking bleach merupakan teknik bleaching internal yang digunakan pada kasus diskolorasi pasca perawatan endodontik. Tujuan laporan kasus ini adalah memaparkan tentang penatalaksanaan diskolorisasi gigi pasca perawatan saluran akar dengan teknik walking bleach. Laporan kasus: Pasien perempuan berusia 20 tahun datang ke RSGM Unpad dengan keluhan gigi depan atas kiri berwarna kecoklatan dan mengganggu penampilan. Pemeriksaan klinis menunjukkan gigi 21 terdapat tumpatan komposit pada mesiobukal disertai diskolorisasi intrinsik dengan warna kecoklatan tampak dominan pada daerah servikal. Hasil tes vitalitas, perkusi dan palpasi negatif. Pemeriksaan radiologis menunjukkan gambaran radiopak menyerupai bahan pengisi saluran akar dari kamar pulpa hingga 2/3 panjang saluran akar. Diagnosis pada kasus ini adalah Previously Treated gigi 21. Perawatan ulang saluran akar dilakukan dan diikuti prosedur bleaching internal dengan teknik walking bleach. Gutta-percha dihilangkan 3 mm di bawah orifice kemudian dibuat barrier semen glass ionomer. Pasta H2O2 35% diletakkan diatas barrier lalu ditutup tumpatan glass ionomer. Setelah 1 minggu didapatkan warna yang sesuai, kalsium hidroksida diaplikasikan pada kamar pulpa. Gigi direstorasi dengan resin komposit 2 minggu kemudian. Aplikasi pasta H2O2 35% dengan teknik walking bleach terbukti dapat mengembalikan warna gigi tersebut. Simpulan: Teknik walking bleach merupakan salah satu pilihan perawatan yang dapat mengatasi diskolorisasi intrinsik pada gigi non vital pasca perawatan endodontik secara efektif.Kata kunci: Diskolorisasi intrinsik, bleaching internal, teknik walking bleach. ABSTRACTIntroduction: Tooth discolouration post-endodontic treatment can be caused by root canal filling materials. The endodontic material left in the pulp chamber will infiltrate the dentinal tubules, thus causing staining. Intrinsic discolouration due to root canal filling is frequently seen in an endodontically-treated third cervical. Walking bleach is an internal bleaching technique used in post endodontic discolouration cases. The purpose of this case report was to describe the management of post-endodontic root canal discolouration with the walking bleach technique. Case report: A 20-year-old female patient came to Universitas Padjadjaran Dental Hospital (RSGM Unpad) with complaints that her maxillary anterior left teeth were brownish and disturbing her appearance. Clinical examination showed that tooth 21 had a mesiobuccal composite fill with intrinsic discolouration, in which the brownish colour was appearing predominantly in the cervical area. Vitality, percussion and palpation test results were negative. Radiological examination showed a radiopaque image resembling a root canal filling material from the pulp chamber to two-thirds of the root canal length. The diagnosis was previously treated tooth. Root canal re-treatment was carried out and followed by an internal bleaching procedure using the walking bleach technique. The gutta-percha was removed 3 mm below the orifice, and a glass ionomer cement barrier was made. 35% H2O2 paste was placed above the barrier and then covered with a glass ionomer spill. After one week of obtaining the appropriate colour, calcium hydroxide was applied to the pulp chamber. The tooth was restored with composite resin two weeks after. The application of 35% H2O2 paste using the walking bleach technique was proven to be able to restore the teeth colour. Conclusion: The walking bleach technique is one treatment option that can effectively treat intrinsic discolouration of non-vital teeth post-endodontic treatment.Keywords: Intrinsic discolouration, internal bleaching, walking bleach technique.

Effect antioxidants application on microshear bond strength of universal adhesive to bleached enamel

Purpose: To evaluate, in vitro, the influence of antioxidants (green tea extract - GT and sodium ascorbate - SA) on microshear bond strength (?SBS) of a universal adhesive system – self-etching mode (UAS) to bleached enamel. Material and Methods: After obtaining 50 fragments of human dental enamel (4 mm x 4 mm), forty fragments were submitted to at-home bleaching technique using 10% carbamide peroxide (Opalescence PF, Ultradent) for two hours/day, for four weeks. They were randomly divided in four groups (n=10): GT - 10% aqueous GT solution (60 minutes); SA - 10% SA solution (10 minutes); Negative control - no antioxidant agent, immediately restored; PC1 (positive control 1) - no antioxidant agent, restored 14 days the bleaching procedure. Ten enamel fragments were assigned to PC2 group (positive control 2), in which the adhesive procedures were realized in non-bleached enamel. The UAS (Adper Single Bond Universal, 3M ESPE) was applied on enamel surface according to manufacturer’s instructions and two cylinders (0,8 mm diameter) of nanoparticulate composite resin (Z350, 3M ESPE) were made on each sample. After 24 hours, the cylinders were submitted to ?SBS in a universal test machine (0.5 mm/min). Fracture mode was evaluated in stereomicroscope (40x magnification). SBS data, in MPa, was submitted to one-way ANOVA (?=0,05). Results: There was no statistical difference between the experimental groups (p=0,545). The fracture mode demonstrated that there was predominance of adhesive fracture in all groups. Conclusion: Neither the bleaching procedure nor the application of antioxidants to bleached enamel interfered in the bond strength of the tested universal adhesive system. KEYWORDS Antioxidants; Dental bleaching; Shear strength.

Effect of Bleaching with 15% Carbamide Peroxide on Flexural Strength of Three Resin-Based Restorative Materials

Objectives: Considering the increasing use of vital bleaching procedures and the increased application of newly introduced resin-based materials for tooth restoration, this study was designed to evaluate the effect of 15% carbamide peroxide gel on the flexural strength of three resin-based restorative materials. Materials and Methods: Three different types of restorative materials namely Beautifil II giomer, Cention N, and Z250 micro-hybrid composite resin were evaluated in this in vitro, experimental study. Twenty-four bar-shaped specimens were prepared from each restorative material, totaling 72 specimens, and were randomly assigned to two subgroups with and without bleaching procedure (n=12). In the bleaching subgroups, 15% carbamide peroxide gel was applied on the specimen surface 8 h a day for 14 days. The flexural strength of the specimens was then measured. Two-way ANOVA was used to compare the flexural strength of the specimens. Results: There was a significant reduction in the flexural strength of materials following exposure to the bleaching agent (P<0.05). The flexural strength was significantly higher in the groups that did not undergo bleaching. However, the mean flexural strength of the restorative materials was not significantly different (P=0.12). Conclusion: The flexural strength of Beautifil II giomer, Cention N, and Z250 micro-hybrid composite resin could be compromised subsequent to bleaching with 15% carbamide peroxide gel. The three resin-based restorative materials exhibited similar flexural strength values irrespective of the use or no use of 15% carbamide peroxide gel.

Effect of Prior Application of Desensitizing Agent on the Teeth Submitted to In-Office Bleaching

This study aimed to quantify the penetration of hydrogen peroxide, color change evaluation, surface morphology, and composition after application of desensitizing agents before in-office bleaching. Fifty premolars were sectioned, an acetate buffer was placed in the pulp chamber and divided into five groups (n=10). In the positive control group, only the in-office bleaching gel was used, and in the negative control group, no treatment was used. Three different desensitizing agents were applied: Desensibilize KF2%® group; Mi Paste® group, and Desensibilize Nano-P® group. The bleaching procedure was carried out with 35% HP. The absorbance of the resulting solution was determined in a spectrophotometer. Color change was assessed by using a digital spectrophotometer. Four additional premolars were assigned to the same groups above for analysis under scanning electron microscope, as well as to evaluate the elemental composition with X-ray dispersive energy spectrometry. Data were subjected to ANOVA and Tukey's test (α=0.05). All products reduced the penetration of HP in the pulp chamber. Mi Paste and Nano P were the products that yielded the lowest HP penetration, which was similar to the negative control group (p<0.001). No significant difference was detected in color change (p<0.001). Concerning enamel morphology, the groups that were analyzed after bleaching were observed a greater deposition of desensitizing agents on the surface. The use of desensitizing agents before tooth bleaching seems to be an alternative to reduce adverse effects of the tooth.

Effect of Bleaching Gel Concentration on Tooth Color and Sensitivity: A Systematic Review and Meta-analysis

SUMMARY Objective: The aim of this systematic review and meta-analysis was to evaluate a high concentration of hydrogen peroxide (35%) regarding tooth sensitivity and color change in tooth bleaching in comparison to low concentrations (6% to 20%). Methods and Materials: This review was conducted using the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and is registered on the Prospective Register of Systematic Reviews (CRD42017064493). The PICO question was “Does a concentration of hydrogen peroxide ≥35% using in-office bleaching procedure contribute to greater tooth sensitivity?” A search was made in PubMed/MEDLINE, Scopus, and the Cochrane Library. Results: Fourteen studies were selected for the qualitative analysis and seven for quantitative analysis. A total of 649 patients were evaluated (mean age: 36.32 years; range: 13.9 to 31 years), and the follow-up period ranged from one week to 12 months. The meta-analysis demonstrated that tooth sensitivity was higher in the patients submitted to treatment involving a high concentration of hydrogen peroxide (0.67; 95% confidence interval [CI]: 0.44 to 1.03; p=0.04; I2: 56%), and a significant difference was found regarding objective color ΔE (1.53; 95% CI: 2.99 to 0.08; p&lt;0.0001; I2: 82%) but no significant difference was found regarding subjective color ΔSGU (0.24; CI: 0.75 to 1.23; p&lt;0.00001; I2: 89%). Conclusions: This study indicated that a lower concentration of hydrogen peroxide causes less tooth sensitivity and better effectiveness in objective color change (ΔE); however, there is no difference between them related to subjective color (ΔSGU).