Impact of combined at-home bleaching and whitening toothpaste use on the surface and color of a composite resin.

Objective: This in vitro study aimed to evaluate the effects of different whitening toothpastes on a composite resin during at-home bleaching with 10% carbamide peroxide. Materials and Methods: Sixty samples (7 mm × 2 mm) were used for color and roughness analyses, while another 60 samples (3 mm × 2 mm) were utilized to assess microhardness. The factors analyzed included toothpaste, for which 5 options with varying active agents were tested (distilled water; conventional toothpaste; whitening toothpaste with abrasive agents; whitening toothpaste with abrasive and chemical agents; and whitening toothpaste with abrasive, chemical, and bleaching agents). Brushing and application of whitening gel were performed for 14 days. Surface microhardness (SMH), surface roughness (Ra), and color (∆L*, ∆a*, ∆b, ∆E*ab, and ∆E00) were analyzed. The Ra and SMH data were analyzed using mixed generalized linear models for repeated measures, while the color results were assessed using the Kruskal-Wallis and Dunn tests. Results: Between the initial and final time points, all groups demonstrated significant increases in Ra and reductions in SMH. No significant differences were found between groups for SMH at the final time point, at which all groups differed from the distilled water group. Conventional toothpaste exhibited the lowest Ra, while whitening toothpaste with abrasive agent had the highest value. No significant differences were observed in ∆L*, ∆a*, and ∆b. Conclusions: While toothpaste composition did not affect the color stability and microhardness of resin composite, combining toothbrushing with whitening toothpaste and at-home bleaching enhanced the change in Ra.

Bond strength of bulk fill composite to teeth prepared with Er: YAG laser

Aim: The present in vitro study aimed to evaluate the bond strength of a bulk fill composite on dentin surfaces prepared with the Er: YAG laser. Methods: Twenty-four permanent third molars were selected and divided into 2 groups: CP - Conventional preparation with high-speed handpiece (control) and LA (laser) - Preparation with Er: YAG laser. The occlusal surface was removed to expose coronal dentin, which was subsequently prepared with a high-speed handpiece or Er: YAG laser (350mJ, 4Hz, 1.5 ml/min water flow). Both groups were restored with Filtek One Bulk Fill (3M ESPE) composite resin. After 24 hours, the samples were evaluated for microtensile bond strength (µTBS), fracture pattern, and scanning electron microscopy (SEM). Results: The data obtained in the µTBS test were submitted to t-test (α=0.05). The results showed no difference in µTBS when the different types of cavity preparation were compared (ρ=0.091). Fracture patterns revealed the prevalence of cohesive fracture in composite resin in CP (83.3%) and adhesive fracture in LA (92.1%). In the SEM analysis, the LA group demonstrated the presence of gaps between the composite resin and the irradiated dentin surface. The hybrid layer exhibited more regularity with the presence of longer and uniform resin tags in the CP group. Conclusion: The type of cavity preparation did not influence the values of bulk fill composite resin µTBS to dentin. Fracture patterns and scanning electron microscopy analyses suggested less interference at the adhesive interface in preparations performed using CP

Effect of bleaching gels with different thickeners under normal and hyposalivation conditions: in situ study.

BACKGROUND: Bleaching gel thickeners induce important changes in tooth enamel and these changes are reversed by saliva. OBJECTIVE: This in situ study aimed to evaluate the effect of bleaching gels with different thickeners on tooth enamel under normal and hyposalivation conditions. METHODOLOGY: Of 28 participants, 14 had normal salivary flow and 14 had low salivary flow. For each salivary flow, four types of treatment were performed with different thickeners: no bleaching (negative control), bleaching with a commercial 10% carbamide peroxide (CP) gel with carbopol (positive control) and bleaching with experimental 10% CP gels with natrosol and aristoflex. Participants used a palatal appliance containing bovine enamel/dentin specimens for 15 days. From day 2 to day 15, specimens were bleached extraorally. The bleaching gel was applied according to the groups for four hours. When the bleaching gel was removed, the palatal appliance was inserted again in the participants' mouth until the next day for another bleaching application. This procedure was repeated for 14 days and on day 15, surface microhardness (SMH), color (ΔE*ab and ΔE00), surface roughness (Ra), scanning electron microscopy (SEM), and energy-dispersive X-ray spectrometry (EDS) analyses were performed and data were subjected to statistical analysis. RESULTS: Neither salivary flow nor thickeners influenced ΔE*ab and ΔE00 results. Carbopol had the lowest SMH, the highest Ra, and the lowest Ca% among all groups. For normal flow, natrosol and aristoflex had higher SMH. For low flow, aristoflex had higher SMH and natrosol and aristoflex had lower Ra. Aristoflex had higher Ca% and Ca/P and differed from carbopol for normal flow. CONCLUSION: For normal flow, 10% CP gels with natrosol and aristoflex caused fewer surface changes, and for low flow, only the 10% CP gel with aristoflex.

Substituição de restauração classe IV em resina composta: relato de caso clínico / Class IV restoration replacement in composite resin: clinical case report

Introdução: a estética é um fator decisivo para a substituição de restaurações anteriores que apresentam falhas, causadas principalmente por alterações na coloração ou fraturas. Objetivo: o presente relato de caso descreve a substituição de uma restauração classe IV insatisfatória, apresentando o protocolo clínico utilizado desde o planejamento até a reabilitação definitiva, com o propósito de difundir o conhecimento sobre a técnica adotada e auxiliar outros profissionais no seu cotidiano clínico. Relato do caso: paciente JPJ, 28 anos, sexo masculino, apresentou-se ao consultório odontológico queixando-se do aspecto estético de uma restauração em resina composta no seu dente anterior. Durante o exame físico intrabucal foi identificada a presença de uma restauração classe IV insatisfatória no elemento 21, apresentando degradação e manchamento superficial. Para uma análise estética completa e planejamento do caso, foram realizadas fotografias intrabucais e moldagem com alginato para confecção de modelos de gesso. Resultados: como tratamento, foi realizado profilaxia, isolamento absoluto e substituição da restauração do dente 21 pela técnica direta com o auxílio de uma guia de silicone. Foi utilizado um sistema adesivo convencional de 2 passos (Single Bond 2, 3M ESPE, St. Paul, MN, USA) e resinas compostas nanohíbridas (Empress Direct, Ivoclar-Vivadent, Barueri, SP, BRA), uma para reprodução do esmalte e outra para dentina. Por fim, foram realizados acabamento e polimento das restaurações. Conclusão: restaurações diretas com resinas compostas, quando bem indicadas e executadas, permitem a devolução da função de forma satisfatória e resultados altamente estéticos.

Introduction: aesthetics are a decisive factor in replacing anterior restorations that present failures, mainly caused by color changes or fractures. Objective: this case report describes the replacement of a class IV restoration with composite resin by the direct technique, presenting the clinical protocol used, from planning to definitive rehabilitation, with the purpose of spreading knowledge of the technique and helping other professionals in their daily clinical routine. Case report: patient JPJ, 28 years old, male, presented to the dental office complaining about the aesthetic aspect of a composite resin restoration on his anterior tooth. During the intraoral physical examination, the presence of a class IV restoration in element 21 was identified, which was unsatisfactory due to degradation and surface staining. For a complete and detailed esthetic analysis, intraoral photographs and molding with alginate were taken to make plaster models. Results: as a treatment, prophylaxis, absolute isolation and replacement of the restoration of tooth 21 were performed by the direct technique with the aid of a silicone guide. A conventional 2-step adhesive system (Single Bond 2, 3M ESPE, St. Paul, MN, USA) and nanohybrid composite resins (Empress Direct, Ivoclar-Vivadent, Barueri, SP, BRA) were used, one for enamel reproduction and another for dentine. Finally, finishing and polishing of the restorations were carried out. Conclusion: direct restorations with composite resins, when properly indicated and executed, allow the return of function in a satisfactory way and highly esthetic results.

Assessment of influence of LED curing units used on microhardness of resin-modified glass ionomer sealants

Aim: Resin modified glass ionomer (RMGI) is class of material that can be used as sealant for preventing and arresting the progression of caries in pits and fissures. As these are hybrid materials, their properties can be affected by factors related to the polymerization process. Therefore, this study aimed to evaluate the influence of different generations of LED curing units (Elipar DeepCure-L and VALO Grand) on Knoop microhardness values (KHN) of RMGI sealants (Clinpro XT and Vitremer). Methods: Forty cylindrical specimens (6mm ø x 1 mm high) were prepared according to the manufacturer's instructions and divided into four groups (n=10) according to the type of RMGI and LED used. The KHN of the top surface of each sample was calculated 7 days after light-curing. Data were submitted to two-way ANOVA (α = 0.05). Results: Vitremer had higher KHN values than Clinpro XT after using both LEDs (p<0.0001), but especially when light-cured with the use of VALO Grand (p<0.0001). Whereas the KHN value of Clinpro was not influenced by the LED device (p>0.05). Conclusions: Top surface microhardness values of RGMI sealants were affected by both material composition and generations of LED curing units used. Third generation LED curing units seemed to be more efficient for the polymerization of RMGI-based sealants

Evaluation of mineral content of tooth enamel after application violet led associated with 35% hydrogen peroxide.

BACKGROUND: The aim of this study was to evaluate the microhardness and quantify the presence of minerals (Calcium and Phosphorous) of tooth enamel submitted to bleaching with violet LED light, either associated with 35% hydrogen peroxide gel, or not. METHODS: Bovine incisors were selected and divided into 4 Groups according to the bleaching technique used: C- Without bleaching (Control); VL- violet LED; HP- 35% Hydrogen Peroxide; HP+VL- 35% Hydrogen Peroxide + violet LED. The response variables were surface microhardness (n = 12), Energy Dispersive Spectroscopy (EDS) (n = 6) and scanning electron microscopy (SEM) (n = 3). RESULTS: The 2-way ANOVA test with repeated measures showed that there was difference in the microhardness values of enamel in the specimens in all of the Groups when the values measured in the initial and final time intervals were compared, however, without significant differences between the values of the different treatments in both time intervals. The results with reference to EDS were analyzed with the 1-way ANOVA test. There was difference among the Groups only in the Ca%, with Group HP obtaining the lowest values, with significant difference from those of the C Group. SEM images showed a smooth, homogeneous enamel surface and similarity among the Groups, irrespective of the treatment performed. CONCLUSIONS: Therefore, it was concluded that the changes caused in enamel by the use of violet LED Light, either associated with 35% hydrogen peroxide, or not, did not differ from those of non-bleached tooth enamel, showing absence of harm to the mineral content of tooth enamel resulting from the use of violet LED.

Effect of at-home bleaching gels with different thickeners on the physical properties of a composite resin without bisphenol A.

OBJECTIVE: To investigate, in vitro, the influence of at-home bleaching with 16% carbamide peroxide (CP) gels containing different thickeners on the color, gloss, roughness, and microhardness of a composite resin with bisphenol A (BPA) and without bisphenol A (BPA-free). MATERIAL AND METHODS: Cylindrical samples (7 × 2 mm) of a composite resin with BPA (Filtek Z350 XT®; 3M/ESPE) and composite resin BPA-free (Vittra APS®; FGM) were subdivided into six subgroups (n = 12), according to the bleaching gel used: no bleaching (control), commercial gel with 16% CP and carbopol, experimental gel with 16% CP and carbopol, experimental gel with 16% CP and natrosol, experimental gel with carbopol and experimental gel with natrosol. At the end of the experimental phase, the specimens were analyzed for color (ΔE*ab and ΔE00 ), surface roughness (Ra), gloss (GU), and surface microhardness (SMH). The data for all analyzes were submitted to Levene's test, Shapiro-Wilk's test and ANOVA. RESULTS: For ΔE*ab and ΔE00 no statistically significant differences were found between all groups evaluated. Bleaching with experimental 16% CP gel with carbopol resulted in the lowest GU values for both composite resins evaluated. 16% CP experimental gel with natrosol resulted in higher Ra for the BPA composite resin and the bleaching with natrosol resulted in higher Ra for BPA-free. About 16% CP experimental gel with carbopol and 16% CP experimental gel with natrosol resulted in the lowest final SMH for composite resin with BPA. For the BPA-free composite resin, no differences were found between the groups in SMH for the same resin, however they presented the lowest values compared with all others groups. CONCLUSION: The effects on physical properties are dependent on the composition of the composite resin and the thickener/bleaching gel used. The BPA-free composite resin showed less changes after exposure to bleaching agent, although its initial physical properties were worse compared to a bleached BPA. CLINICAL RELEVANCE: The hydrogen peroxide and thickener of the at-home bleaching gel does impact the properties of composites with BPA or BPA-free such as gloss, roughness and surface microhardness, extremely important factors for maintaining an aesthetically and physically satisfactory restoration. BPA-free composite resins have inferior properties after at-home bleaching with different thickeners.

In-office tooth bleaching with chitosan-enriched hydrogen peroxide gels: in vitro results.

OBJECTIVE: This study aimed to evaluate the effects of adding chitosan to 35% hydrogen peroxide gels (for in-office bleaching), with or without calcium gluconate, on tooth properties and bleaching efficacy. METHODS: Bovine enamel/dentin specimens (4 × 4 × 2.5 mm) were randomly allocated into groups (n = 10): negative control (unbleached), bleaching with 35% hydrogen peroxide gel (35% HP, commercial gel); 35% HP with 2% chitosan (% wt) (35% HP + chitosan), 35% HP and calcium (35% HP + Ca, commercial gel), and 35% HP + Ca + 2% chitosan. Variation of surface profile (ΔRa) and color analyses (ΔL*, Δa*, Δb*, ΔE*ab, ΔE00, and ΔWID) were performed comparing specimens at baseline (initial) and 24 h after of storage in artificial saliva (final). Surface microhardness (KHN) values and scanning electron microscopy (SEM) images were obtained on conclusion. The data were analyzed by ANOVA and Tukey's tests (KHN), generalized linear models (ΔL*, ΔEab, ΔE00, ΔWID, ΔRa), and Kruskal-Wallis and Dunn tests (Δa*, Δb*) (α = 0.05). RESULTS: Considering ΔL*, Δa*, Δb*, ΔE*ab, ΔE00, and ΔWID values, the bleached groups differed from negative control. For ΔRa, chitosan-based groups showed lower variation in surface roughness compared to 35% HP, without significant difference from negative control. For KHN, chitosan groups did not differ from negative control (unbleached control = chitosan groups > 35% HP + Ca > 35% HP). For SEM, slight surface changes were observed in all bleached groups, but the intensity varied according to gel used (35% HP > gels with Ca > gels with chitosan). CONCLUSION: Chitosan-enriched hydrogen peroxide gels can reduce negative impacts on tooth properties without affecting bleaching efficacy. CLINICAL RELEVANCE: Although commercial gels containing remineralizing agents such as calcium reduce the negative effects on the properties of teeth, the addition of chitosan appears to be a promising approach to preservation of dental properties without interfering in bleaching efficacy.

Effect of bleaching gels with different thickeners under normal and hyposalivation conditions: in situ study

Abstract Bleaching gel thickeners induce important changes in tooth enamel and these changes are reversed by saliva. Objective This in situ study aimed to evaluate the effect of bleaching gels with different thickeners on tooth enamel under normal and hyposalivation conditions. Methodology Of 28 participants, 14 had normal salivary flow and 14 had low salivary flow. For each salivary flow, four types of treatment were performed with different thickeners: no bleaching (negative control), bleaching with a commercial 10% carbamide peroxide (CP) gel with carbopol (positive control) and bleaching with experimental 10% CP gels with natrosol and aristoflex. Participants used a palatal appliance containing bovine enamel/dentin specimens for 15 days. From day 2 to day 15, specimens were bleached extraorally. The bleaching gel was applied according to the groups for four hours. When the bleaching gel was removed, the palatal appliance was inserted again in the participants' mouth until the next day for another bleaching application. This procedure was repeated for 14 days and on day 15, surface microhardness (SMH), color (ΔE*ab and ΔE00), surface roughness (Ra), scanning electron microscopy (SEM), and energy-dispersive X-ray spectrometry (EDS) analyses were performed and data were subjected to statistical analysis. Results Neither salivary flow nor thickeners influenced ΔE*ab and ΔE00 results. Carbopol had the lowest SMH, the highest Ra, and the lowest Ca% among all groups. For normal flow, natrosol and aristoflex had higher SMH. For low flow, aristoflex had higher SMH and natrosol and aristoflex had lower Ra. Aristoflex had higher Ca% and Ca/P and differed from carbopol for normal flow. Conclusion For normal flow, 10% CP gels with natrosol and aristoflex caused fewer surface changes, and for low flow, only the 10% CP gel with aristoflex.

Effect of tooth bleaching and application of different dentifrices on enamel properties under normal and hyposalivation conditions: an in situ study.

OBJECTIVE: The purpose of this in situ study was to evaluate different dentifrices on enamel after bleaching under normal and hyposalivatory conditions. MATERIALS AND METHODS: Twenty-four participants were assigned of which 12 had normal and 12 had low salivary flow. The study was conducted in 6 in situ experimental phases of 24 h duration: placebo, NaF, SnF2, F/Sn/Chitosan, F/Arginine, and F/Bioactive Glass. The specimens were previously bleached in vitro. Microhardness (SMH), roughness (Ra), and color analyses (CIELAB and ΔE00) were performed at baseline (T1), after bleaching (T2) and after in situ phase (T3). Scanning electron microscopy (SEM) and the elemental levels (wt%) of Ca, P, and Na and the proportion between Ca and P were determined using an energy-dispersive X-ray spectrometer (EDS) in T3. The SMH and Ra were analyzed by mixed models for repeated measures and Tukey Kramer. The color and Na% were analyzed by split-plot ANOVA and Tukey test. The EDS were analyzed by Mann's Whitney nonparametric, Friedman, and Nemenyi tests (p<0.05). RESULTS: The dentifrices placebo and NaF in the low flow presented lower SMH and higher Ra in T3 and lower Ca% compared to the same dentifrices in normal flow. For normal flow, SnF2 resulted in greater SMH. For low flow, SnF2, F/Sn/Chitosan, and F/Bioactive Glass resulted in higher SMH in T3 and did not differ from T1. F/Bioactive Glass showed lower Ra among the dentifrices evaluated for both salivary flows, whereas SnF2 showed the highest. F/Bioactive Glass showed a statistically significant difference from placebo for Ca%, P%, Na%. For ΔE*ab and ΔE00 (T1×T3), no differences were found for the dentifrices and salivary flows. CONCLUSION: The low salivary flow had less capacity for remineralization of bleached enamel compared to normal flow. Overall, the dentifrice with bioactive glass had the best performance in bleached enamel under low and normal salivary flow condition. CLINICAL RELEVANCE: It is recommended to use a bioactive glass-based dentifrice after bleaching to promote tooth enamel recovery for patients with or without impaired salivary flow.

Influence of cigarette smoke combined with different toothpastes on enamel erosion.

This in vitro study aimed to evaluate the effect of different toothpastes on dental enamel subjected to an erosive cycle with and without exposure to cigarette smoke. Bovine enamel specimens were randomly allocated into 12 groups (n = 12). For the in vitro simulation of smoking, half the groups underwent an exposure cycle of 20 cigarettes per day for 5 days. Subsequently, all groups were subjected to a 5-day erosion cycle intercalating demineralization (1 min; 1% citric acid; pH = 3.5) and treatment with toothpaste slurries (2 min) of NaF, SnF2, F/Sn/Chitosan, F/CaSiO3/Na3PO4, and F/bioactive glass. The control group was immersed in distilled water. Surface microhardness (SMH) was measured initially, after exposure to smoke, and after the erosive cycle, and %SMH was calculated. At the end of the experimental cycle, surface roughness, profilometry, and atomic force microscopy (AFM) were performed. SMH increased after exposure to cigarette smoke (p < 0.05). After the erosive cycle, there were no differences between the presence and absence of cigarette smoke exposure in SMH and roughness (p > 0.05). Besides increasing enamel SMH, cigarette smoke did not prevent enamel loss after the erosion cycle (p < 0.05). In profilometry, roughness and surface loss had the lowest values in the groups treated with SnF2 and F/Sn/Chitosan (p < 0.05). AFM showed lower mineral loss with F/CaSiO3/Na3PO4 and F/Sn/Chitosan. For all groups, except F/CaSiO3/Na3PO4, cigarette smoke resulted in higher enamel wear. F/Sn/Chitosan showed the best results against erosion.

Treatment of non-carious lesions: diagnosis, restorative materials and techniques

Management of non-carious cervical lesions (NCCLs) still is a challenge in clinical practice. The diagnosis is the key to treat these lesions successfully. Aim/Case report: Therefore, the aim of this case report is to describe the diagnosis and treatment of generalized abfraction lesions associated to abrasion lesions of a 43 years old patient and to discuss considerations about the technique and materials to be used appropriately. After the diagnosis, a treatment plan with preventive and restorative approach was elaborated. The occlusal adjustment was performed to distribute the contact points and the patient was instructed in relation to tooth brushing habits. It was also recommended that the patient use a dentifrice with potassium nitrate for the control of sensitivity. For lesions over 1mm deep, the restorative treatment was performed using the self-etching adhesive system and nanohybrid composite by the stratification technique. Unsatisfactory restorations have been replaced. Occlusal splint was done and the patient was instructed to use the device every day overnight. One year after treatment, follow-up was performed. The appearance of new NCCLs was not observed. There was no progression of lesions smaller than 1 mm. There was no loss of restorations. All restorations were fully satisfactory and the patient reported absence of dentin hypersensitivity. Conclusion: The treatment performed besides being aesthetically satisfactory after 1 year resulted in the control of the disease, preventing the appearance of new lesions and guaranteeing a better quality of life to the patient

Effect of different concentrations of nanohydroxyapatite on tooth bleaching effectiveness and enamel bond strength / Efeito de diferentes concentrações de nanohidroxiapatita na efetividade clareadora e força de adesão ao esmalte

Objective: To evaluate the effect of 35% hydrogen peroxide (35% HP) combined to different concentrations of nanohydroxyapatite (nHA) on the effectiveness of dental bleaching (superficial enamel and deep dentin) and enamel bond strength. Material and Methods: Fifty bovine dental specimens (5x5x2mm) were divided into 5 groups, according to the treatments (n = 10): no bleaching (negative control); 35% HP (positive control); 35% HP+ 5% nHA; 35% HP + 10% nHa; and 35% HP + 15% nHA. Three in-office bleaching sessions were made. The color analysis was performed on the enamel surface and the opposite dentin, using a spectrophotometer. The results were expressed in the CIE L*a*b* system. After this, the adhesive system was applied to the tooth structure, and the dental specimens received a composite restoration. The microshear bond strength test was performed 24 h after the restoration. Data were submitted to ANOVA and Tukey's test (α=0.05). Results: For the enamel color analysis, all bleached groups differed statistically from the unbleached group, with increasing L* values and decreasing b* values. The addition of different concentrations of nHA did not interfere with the bleaching effectiveness for the enamel and opposite dentin. For microshear bond strength, no statistically significant differences were presented between groups. The adhesive failure rate of the 35% HP + 10% nHA group was lower than the 35% HP group and similar to the negative control. Conclusion: The addition of different concentrations of nHA in 35% of hydrogen peroxide did not interfere with the bleaching efficacy of enamel and deep dentin and did not affect the enamel bond strength after bleaching.(AU)

Objetivo: avaliar o efeito do peróxido de hidrogênio a 35% (HP 35%) associado a diferentes concentrações de nanohidroxiapatita (nHA) sobre a efetividade clareadora do esmalte superficial, dentina profunda e da força de adesão ao esmalte. Material e Métodos: Cinquenta espécimes bovinos (5x5x2mm) foram divididos 5 grupos (n = 10): sem clareamento (controle negativo); HP 35% (controle positivo); HP 35% + nHA 5%; HP 35% + nHA 10%; e HP 35% + nHA 15%. Três sessões de clareamento de consultório foram realizadas. A análise de cor foi realizada na superfície do esmalte e na dentina oposta e os resultados expressos no sistema CIE L*a*b*. Depois disso, os sistemas adesivos foram aplicados no esmalte, e os blocos receberam uma restauração em resina composta. O teste microcisalhamento foi realizado 24 h após a restauração. Os dados foram submetidos à ANOVA e ao teste de Tukey (α = 0,05). Resultados: Para a análise de cor do esmalte, todos os grupos clareados diferiram estatisticamente do grupo não clareado. A adição de diferentes concentrações de nHA não interferiu com a eficácia clareadora para o esmalte e dentina. Para o microcisalhamento, não houve diferença entre os grupos. A taxa de falha adesiva do grupo HP 35% + nHA 10% foi menor do que o grupo HP 35% e similar ao controle negativo. Conclusão: a adição de diferentes concentrações de nHA em PH 35% não interferiu na eficácia clareadora do esmalte e da dentina e não afetou a força de adesão do esmalte após o clareamento (AU)