Association of Papacarie Duo® and low-level laser in antimicrobial photodynamic therapy (aPDT).

Dental caries is a multifactorial, non-communicable disease. Effective treatment options for minimally invasive removal of carious tissue include Papacarie Duo® gel and antimicrobial photodynamic therapy (aPDT). aPDT involves a combination of a light source and photosensitizer. Given that Papacarie Duo® contains a percentage of blue dye, this study aims to explore the antimicrobial potential of Papacarie Duo® when associated with a light source against Streptococcus mutans strains. The chosen light source was a low-power diode laser (λ = 660 nm, E = 3 J, P = 100 mW, t = 30 s). To assess antimicrobial capacity, planktonic suspensions of Streptococcus mutans were plated on Brain Heart Infusion Agar (BHI) to observe the formation of inhibition halos. The studied groups included methylene blue (0.005%), Papacarie Duo®, distilled water (negative control), 2% chlorhexidine (positive control), Papacarie Duo® + laser, and methylene blue (0.005%) + laser. Following distribution onto plates, each group was incubated at 37 °C for 48 h under microaerophilic conditions. Inhibition halos were subsequently measured using a digital caliper. The results showed that chlorhexidine had the greatest antimicrobial effect followed by the group of irradiated methylene blue and irradiated Papacarie Duo®. All experimental groups demonstrated antimicrobial potential, excluding the negative control group. The study concludes that Papacarie Duo® exhibits antimicrobial properties when associated with a low-power diode laser.

Use of high-power lasers in pediatric dental surgeries: case reports.

The use of high-power diode laser technology follows the principles of minimally invasive dentistry. Laser technology is used frequently in pediatric dentistry, especially in surgical procedures, because this approach favors hemostasis, eliminates the use of sutures, improves healing, minimizes treatment time, reduces the sensation of pressure and vibration experienced by the patient, and creates more comfortable postoperative conditions. This article describes the use of high-power diode lasers to perform 3 minor oral surgical procedures--biopsy, lingual frenectomy, and operculectomy--in 2 children. In all 3 treatments, the operative time did not exceed 5 minutes, no sutures were used, and no postoperative complications were reported. Thus, high-power diode lasers can be considered an alternative approach to minor oral surgery that decreases chair time, reduces postoperative complications, and minimizes stress and anxiety in pediatric patients.

Influence of biosafety materials of the laser output power.

Biosafety materials used in the correct handling of low power laser equipment may interfere on the power delivered at the target tissue and, possibly, on the effects on biological tissues. The aim of this study was to evaluate the interference of the use of polyvinyl chloride (PVC) and polyethylene (PEAD) protection materials on the output power of low power lasers. Two low power diode laser devices with different wavelengths (red and infrared) were used. For each wavelength, two protection materials and two evaluation times (before and after protection) were considered. The output power (mW) was measured with the tip positioned in close contact with the power meter receiver. Parametric statistical test, two-way ANOVA for repeated measures (protection material and time), was performed considering the level of significance of 5%. In respect to "time", all groups had the output power reduced after placing the protective material (p < 0.05). Comparing the protection materials, the PEAD showed a greater reduction in output power than the PVC for both red and infrared wavelengths. It was concluded that, among the biosafety materials tested, PVC is the most suitable for the protection of the tip of the low power lasers.

Clinical Evaluation of Bilateral Multiple Gingival Recession Treatment with Autogenous Connective Tissue Graft Associated with Low-Level Laser Therapy.

BACKGROUND: Gingival recession (GR) is described as an apical displacement of the gingival margin in relation to the cementoenamel junction, exposing the root surface to the oral cavity environment. This study aimed to evaluate the clinical results of a bilateral root coverage (RC) of GR associated with an autogenous connective tissue graft (aCTG) alone or combined with low-level laser therapy (aCTG + LLLT). METHODS: This cross-sectional, split-mouth, double-blind, clinical pilot study featured three individuals who attended a periodontics post-graduate program with the main complaint of GR and dental hypersensitivity (DHS). Of these, only one patient met the inclusion criteria and the parameters evaluated were: DHS, the keratinized tissue's thickness and width clinical attachment level (CAL), probing on depth (PD), and bilateral GR based on Cairo RT I. The patient was evaluated by a first clinical evaluator and the treatment was randomly divided into two groups, G1: aCTG only (control group, n = 3 teeth per side) and G2: aCTG + LLLT (test group, n = 3 teeth per side). LLLT used a diode laser (660 nm) with a dose of 3 J/cm2 per point and 4 s per point was applied in four different periods, preoperatively; transoperatively and immediately postoperatively, the application was performed in three points (eight applications) on alternate days for 7 days and a 90-day follow-up was performed for clinical evaluations of the periodontal parameters and the collected data were analyzed by Kruskal-Wallis and Dunn tests. RESULTS: the RC mean percentage was <95% in both groups after 90 days. Comparing treatment sides, G1 (n = 3/3, 100%) had a higher prevalence of RC than G2 had (n = 3/3, 95%). DHS significantly decreased after 90 days in both groups. Both groups showed an improvement in the other periodontal parameters evaluated during the short-term follow-up; mainly, PD had a statistically significant (p ˂ 0.05) increase after 90 days and a CAL decrease during this period; KTW and KTT also had a significant increase in both groups (p ˂ 0.05). CONCLUSIONS: the results indicated that aCTG + LLLT might have an additional benefit to GR root coverage within the evaluated time and this section also includes the within-study limitations.

Violet led dental whitening: Effectiveness and biological safety: An in vitro study.

INTRODUCTION: The light-emitting diode (Led) in the violet spectrum associated or not with hydrogen peroxide (HP) has been suggested as a promising technique for dental bleaching. Violet led has a wavelength of 405-410 nm, which is very close to that of ultraviolet (UV) radiation, and this has raised biological safety concerns. AIM: To investigate the effectiveness of the violet led dental bleaching technique by evaluating color parameters, enamel surface microhardness, and biological safety analysis. METHODS: One hundred bovine dental blocks were divided into groups according to the bleaching technique (G1 - only HP; G2 - HP associated with blue led; G3 - only blue led; G4 - HP associated with a violet led; and G5 - only violet led). The color analysis (ΔE, ΔL, and WID) and enamel surface microhardness were assessed before and after bleaching (immediately, 5, 14, and 30 days). The biological safety of the violet led irradiation was assessed by measuring the number of micronuclei formed in human cells in culture in response to irradiation. Data analysis included Kruskal-Wallis test, Friedman test, and Mann-Whitney test. RESULTS: In groups G4 and G5 there was the formation of precipitates on the enamel surface. At the time of 14 days, it was observed that the G2 group had lower values of microhardness than G5. ΔL and ΔE showed differences between groups in experimental times. Mean percentages of micronuclei occurrence were similar in the control group and the violet led group. CONCLUSION: The violet led irradiation can be applied for dental bleaching because this approach produces significant color changes preserving tooth enamel integrity and causes no genotoxic effects on vital cells.

How to use laser safely in times of COVID-19: Systematic review.

AIM: To conduct a systematic review of the literature on biosafety with the use of lasers. METHODS: The systematic review of literature was performed using MEDLINE (PubMed), Science Direct and Web of Science databases. The electronic search strategy included terms in the Medical Subject Heading (MeSH) related to biosafety in dentistry and laser, forms of contamination with aerosols, as well as their synonyms. The selected keywords were "aerosol virus transmission dentistry," "laser-generated air contaminants," "biosafety dentistry laser" combined with the terms AND/OR. RESULTS: A total of 1334 abstracts were reviewed, resulting in inclusion of 23 reviews. The dental surgeons are professionals with a high risk of contamination; high-power lasers form aerosols that need to be controlled and low-power lasers must be protected to minimize the risks of cross-infection. CONCLUSION: The biosafety of using lasers is important for professionals can be more oriented as to the correct use of this equipment. This study has the relevance of showing biosafety measures for the professional, staff and patients, as well as suggesting that more studies that are clinical should be conducted in this area.

In-office bleaching protocols using violet LED: A split mouth case report.

A new LED wavelength, violet LED (VL) with a wavelength between 405 - 410 nm was recently introduced to be used for in-office dental bleaching. In comparison to the blue LED system (440 to 485 nm), the shorter wavelength has more energy carried in its photons and also corresponds to the absorption peak of the stained particles, which lead to whitening utilizing a physical process. Considering the need to suggest and develop new protocols with this new technology, this article reports 2 different dental bleaching protocols developed in a split-mouth model using VL. A 25-year-old male patient was submitted to in-office dental bleaching. On the teeth from the left side, the bleaching gel (35% H2O2) was renewed 3 times (every 8 mins), and on the right side, the gel was maintained without renewal during the bleaching session. The irradiation with Violet LED Light (405 nm ± 10 nm) was performed with the following protocol: 1 min of irradiation with 30 s light off until 8 min of total time. A total of 3 cycles were performed (total time of 24 min). Two bleaching sessions were performed with an interval of 7 days between sessions. Based on the results of this split-mouth case report, there was no visible difference in the final color outcome and sensitivity between both bleaching protocols tested.

Does pre-irradiation time influence the efficacy of antimicrobial photodynamic therapy?

Antimicrobial photodynamic therapy (aPDT) has emerged as a promising antimicrobial treatment to control microorganisms including those involved in oral diseases, especially dental caries. Hence, the aim of this study was to evaluate the influence of aPDT - pre-irradiation time (PIT), at different periods, on antimicrobial rate of Streptococcus mutans (S. mutans). A standard suspension of S. mutans UA159 was prepared and submitted at sensitization of 0.005 % methylene blue (MB) for 0, 1, 3 and 5 min (G1 - G4 groups, respectively) and irradiated with a red laser (660 nm; 321 J/cm2; 9 J; 90 s) afterward. A control group using PBS instead of MB was performed as well (G5). The number of colony-forming units (CFU)/mL was recorded, transformed into log10 and analyzed by ANOVA and Tukey's test at a cutoff value at 0.05. Overall, the aPDT groups tested achieved a bacterial reduction > 1-log10 when compared to G5 (p < 0.05) with no statistical difference among the different PIT tested. The need of PIT before aPDT application deserves attention, since its time reduction implies on shorter clinical approaches without compromising the photodynamic antibacterial efficacy in the in vitro parameters employed.

Correspondence between try-in pastes and resin cements, and color stability of bonded lithium disilicate disks.

This study investigates the color correspondence of resin cements and try-in pastes, and the color stability of bonded lithium disilicate ceramic disks. Resin composite disks were fabricated (n = 36) to serve as the background for lithium disilicate disks prepared in two thicknesses (0.5 and 1.0 mm, n = 18 each). Two brands were used for try-in and cement procedures: Variolink Veneer and AllCem Veneer. For baseline, water was applied between the ceramic disks and their respective backgrounds to achieve the control group. This set was subjected to color measurement using an intraoral measurement device (T0). The try-in was inserted between background and ceramic, and this set was subjected to color measurement (T1). After adhesive procedures, the ceramic disk was placed under cement, and color measurement was performed with uncured cement (T2) and 24 h after light-curing (T3). Each set was immersed in distilled water and thermal-cycled, with color measurement being performed after 10,000 (T4) and 20,000 (T5) cycles. Color differences were calculated by CIELab (rEab) and CIEDE2000 (rE00). Data were analyzed by two-way ANOVA for repeated measurements and Tukey's test (α=5%). There was color correspondence of try-in and resin cement for the Variolink system, regardless of the ceramic thickness (p > 0.05). For the AllCem system, the thickness significantly influenced the color measurement (p < 0.001). The Variolink system also demonstrated color stability after 20,000 thermal cycles with rEab < 3.46 and rE00 < 2.25. It was concluded that the color correspondence between a try-in and its respective cement may vary according to resin cement composition.

High Power Laser and Photobiomodulation in Oral Surgery: Case Report.

Introduction: The labial frenum is a fold of mucous membrane that attaches the lip and the cheek to the alveolar mucosa, the gingiva, and the underlying periosteum. In some cases, its presence can cause a midline diastema, periodontal diseases related to food impaction, or retention of biofilm, among others. In such cases, lip frenectomy is indicated as treatment, which can be performed with a scalpel (conventional method), an electric scalpel, or a surgical laser. Objective: To show a clinical case performed at Laser Extension Project in Dentistry, Federal University of Maranhão grounded in a literature review. Case Presentation: A laser frenectomy was performed on a female patient, aged 20, who had a diastema between the upper central incisors and an indication for frenum removal. The high-power diode laser is excellent for procedures in soft tissue because its wavelength is well absorbed by hemoglobin and other pigments; its use also allows a reduction in the amount of anesthetic and medicines used. The parameters used were 2 W, in a continuous mode, 808 nm infrared emission; with delivery of the beam through optical fiber 300 µM; energy of 120 J; 20 pps. Conclusion: the high power diode laser allowed a satisfactory result, the procedure was safe, the technique was a simple one and of reduced clinical time, as mentioned in the literature. It is worth noting that the technique is dependent on the skill of the professional performing it.

Effect of Terminalia catappa Linn. on Biofilms of Candida albicans and Candida glabrata and on Changes in Color and Roughness of Acrylic Resin.

This study aimed to investigate the effect of the n-butanol fraction of Terminalia catappa Linn., (FBuTC) on biofilm of Candida albicans and Candida glabrata, as well as changes in color and roughness of polymethyl methacrylate resin (PMMA). The susceptibility of C. albicans and C. glabrata to FBuTC was evaluated by means of the Minimum Inhibitory and Minimum Fungicidal Concentration (MIC and MFC). PMMA acrylic resin discs (N= 108) were fabricated. For the susceptibility tests, biofilms of C. albicans and C. glabrata were developed on discs for 48 h and immersed in phosphate-saline buffer solution (PBS), 1% sodium hypochlorite (SH 1%), or FBuTC at MIC, 5xMIC, or 10xMIC. For the color and roughness change tests, the discs were immersed in distilled water, SH 1%, or FBuTC in the concentrations of 0.25 mg/mL, 2.5 mg/mL, or 25.0 mg/mL. After 28 days of incubation, color change was evaluated by spectrophotometry and roughness, by using a profilometer. The biofilms were investigated by one-way ANOVA and, the color and roughness changes (two-way ANOVA and the Tukey test; α=0.05). For both MIC and MFC the value of 0.25 mg/mL of FBuTC was observed for the planktonic cells of C. albicans and C. glabrata. Exposure to FBuTC at 10xMIC had a significant effect on the biofilm of C. albicans, showing a reduction in cell counts when compared with PBS, (p=0.001). For the biofilm of C. glabrata, the MIC was sufficient for significantly reducing the cell count (p<0.001). No important changes in color and roughness of the acrylic resin were observed, even after 28 days, irrespective of the concentration of FBuTC used (p >0.05). It could be concluded that the immersion of acrylic resin for dental prosthesis in FBuTC was effective in reducing the biofilms of C. albicans and C. glabrata without evidence of change in roughness and color of this substrate.

Is It Necessary to Prepare the Enamel before Dental Bleaching?

The aim of this in vitro study was to assess the influence of distinct surface treatments on the microhardness and color of enamel that will be bleached. Surface treatments are tested, accordingly: G1, no treatment; G2, 2% sodium fluoride; G3, casein phosphopeptide paste; G4, 2% fluoride+Nd:YAG laser. Forty blocks from bovine teeth composed the sample that were tested in Knoop microhardness (n = 10) and in color change (n = 10). After 24 h, bleaching with 35% hydrogen peroxide was performed for 45 min. Microhardness and color changes (using parameters ΔE, ΔL, Δa, and Δb) were assessed before and after bleaching. The data were analyzed by two-way ANOVA and Tukey's test (p < 0.05). Despite all surface treatments, a reduction of enamel microhardness occurred immediately after bleaching in all groups, being greater in G1. Enamel color changed in all groups. Immediately after bleaching, there was a decrease on enamel microhardness. However, after 7 days, some of those specimens previously treated before bleaching significantly recovered their initial microhardness without influencing the esthetic results of bleaching.

Does the hybrid light source (LED/laser) influence temperature variation on the enamel surface during 35% hydrogen peroxide bleaching? A randomized clinical trial.

OBJECTIVE: The present study investigated how a hybrid light source (LED/laser) influences temperature variation on the enamel surfaces during 35% hydrogen peroxide (HP) bleaching. Effects on the whitening effectiveness and tooth sensitivity were analyzed. METHOD AND MATERIALS: Twenty-two volunteers were randomly assigned to two different treatments in a split-mouth experimental model: group 1 (control), 35% HP; group 2 (experimental), 35% HP + LED/laser. Color evaluation was performed before treatment, and 7 and 14 days after completion of bleaching, using a color shade scale. Tooth sensitivity was assessed using a visual analog scale (VAS; before, immediately, and 24 hours after bleaching). During the bleaching treatment, thermocouple channels positioned on the tooth surfaces recorded the temperature. Data on color and temperature changes were subjected to statistical analysis (α = 5%). Tooth sensitivity data were evaluated descriptively. RESULTS: Groups 1 and 2 showed mean temperatures (± standard deviation) of 30.7 ± 1.2 °C and 34.1 ± 1.3 °C, respectively. It was found that there were statistically significant differences between the groups, with group 2 showing higher mean variation (P < .0001). The highest temperature variation occurred for group 2, with an increase of 5.3 °C at the enamel surface. The color change results showed no differences in bleaching between the two treatment groups (P = .177). The variation of the average temperature during the treatments was not statistically associated with color variation (P = .079). Immediately after bleaching, it was found that 36.4% of the subjects in group 2 had mild to moderate sensitivity. In group 1, 45.5% showed moderate sensitivity. In both groups, the sensitivity ceased within 24 hours. CONCLUSION: Hybrid light source (LED/ laser) influences temperature variation on the enamel surface during 35% HP bleaching and is not related to greater tooth sensitivity.

Correspondence between try-in pastes and resin cements, and color stability of bonded lithium disilicate disks

Abstract: This study investigates the color correspondence of resin cements and try-in pastes, and the color stability of bonded lithium disilicate ceramic disks. Resin composite disks were fabricated (n = 36) to serve as the background for lithium disilicate disks prepared in two thicknesses (0.5 and 1.0 mm, n = 18 each). Two brands were used for try-in and cement procedures: Variolink Veneer and AllCem Veneer. For baseline, water was applied between the ceramic disks and their respective backgrounds to achieve the control group. This set was subjected to color measurement using an intraoral measurement device (T0). The try-in was inserted between background and ceramic, and this set was subjected to color measurement (T1). After adhesive procedures, the ceramic disk was placed under cement, and color measurement was performed with uncured cement (T2) and 24 h after light-curing (T3). Each set was immersed in distilled water and thermal-cycled, with color measurement being performed after 10,000 (T4) and 20,000 (T5) cycles. Color differences were calculated by CIELab (rEab) and CIEDE2000 (rE00). Data were analyzed by two-way ANOVA for repeated measurements and Tukey's test (α=5%). There was color correspondence of try-in and resin cement for the Variolink system, regardless of the ceramic thickness (p > 0.05). For the AllCem system, the thickness significantly influenced the color measurement (p < 0.001). The Variolink system also demonstrated color stability after 20,000 thermal cycles with rEab < 3.46 and rE00 < 2.25. It was concluded that the color correspondence between a try-in and its respective cement may vary according to resin cement composition.

Microtensile bond strength of enamel after bleaching.

OBJECTIVE: To evaluate the bond strength of a composite resin to the bovine enamel bleached with 35% hydrogen peroxide. It was used an etching-and-rinse adhesive system employed immediately, 7 and 14 days after the bleaching. MATERIALS AND METHODS: Twenty bovine teeth were randomly distributed into 4 groups (n = 5), 3 experimental and 1 control. G1: Unbleached + restoration 14 days after storage in artificial saliva (control); G2: Bleached + restoration immediately after bleaching; G3: Bleached + restoration 7 days after bleaching; G4: Bleached + restoration 14 days after bleaching. Their buccal enamel surfaces were flattened, and a 25 mm² (5 × 5 mm) area from each one of these regions was outlined so as to standardize the experimental region. Universal hybrid composite resin Filtek™Z350 was inserted into four layers of 1 mm each and photo-activated. The bond strength was quantitatively evaluated by a microtensile test (1.0 mm/min) 24 h after the restorative procedures. The failure mode was assessed through scanning electron microscopy (SEM). RESULTS: There was a significant reduction in the bond strength of the restored teeth immediately after the bleaching (G2). There were no significant differences in enamel bond strength between groups G1, G3, and G4. There was a predominance of adhesive and mixed (cohesive + adhesive) failure in all groups. CONCLUSION: The 7-day-period after the end of the bleaching with 35% hydrogen peroxide was enough to achieve the appropriate values of bond strength to the enamel.

Evaluation of the bond strength between a composite resin and enamel submitted to bleaching treatment and etched with Er:YAG laser.

BACKGROUND: The use of laser irradiation for dental surface treatment may increase tooth-composite bond strength. Its use on bleached teeth may decrease the waiting time between bleaching and restorative procedures. OBJECTIVE: This study aimed to evaluate the bond strength between a composite resin and bovine enamel bleached with 35% hydrogen peroxide and etched with Er:YAG laser. MATERIALS AND METHODS: Thirty bovine teeth were randomly divided into six groups (n = 5): G1, unbleached and restored 24 h after storage in artificial saliva, etching with 35% phosphoric acid (PA) (control); G2, unbleached and restored 24 h after storage in artificial saliva, etching with Er:YAG laser and 35% PA; G3, bleached and restored immediately afterward, etching with 35% PA; G4, bleached and restored 24 h after bleaching, etching with 35% PA; G5, bleached and restored immediately afterward, etching with Er:YAG and 35% PA laser; G6, bleached and restored 24 h after bleaching, etching with Er:YAG laser and 35% PA. Bond strength was quantitatively evaluated by microtensile test (1.0 mm/min). Data were submitted to statistical analysis using ANOVA and Tukey tests (α = 0.05). RESULTS: Bond strength values (MPa) were G1, 26.17 ± 4.44; G2, 28.87 ± 3.94; G3, 17.25 ± 4.58; G4, 21.93 ± 5.02; G5, 16.69 ± 2.31; and G6, 29.06 ± 8.31. There was no statistically significant difference among groups G1, G2, and G6 (p = 0.119), which presented higher bond strength than group G4, followed by groups G3 and G5. CONCLUSION: Er:YAG irradiation of bleached surfaces may favor bonding procedures when performed 24 h after bleaching.

A comparative leakage study on Er, Cr: YSGG laser- and bur- prepared Class V cavities restored with a low-shrinkage composite using different filling techniques

Aim: To evaluate the leakage on Er,Cr:YSGG laser- and bur- prepared Class V cavities restoredwith a silorane-based composite resin using different insertion techniques Methods: 40 cavitieswere outlined according to: the type of instrument [Er,Cr:YSGG laser (3.0 W power, energy perpulse of 150 mJ, fluence of 53.57J/cm2, pulse duration of 140-200 μs, 20 Hz repetition rate and55/65% air/water spray) or diamond bur]; and the type of filling technique (bulk increment orincremental). Four experimental groups were obtained (n=10): G1- diamond bur (DB) andincremental (I); G2- DB and bulk increment (BI); G3- Er,Cr:YSGG and I; and G4- Er,Cr:YSGGand BI. Specimens were restored with a silorane-based composite resin (Filtek P90, 3M/ESPE),subjected to 500 thermal cycles, sealed, infiltrated with 2% (w/v) methylene blue and sectioned inhalves. Specimen analysis was scored based on a scale. Statistical analyses were done usingthe Kruskal-Wallis and Student Newman-Keuls tests (α=0.05). Results: Statistically significantdifferences were observed between G2 and G4 (p=0.003) and between G1 and G2 (p=0.028).The filling technique did not influence the pattern of dye leakage in the cavity walls (p=0.151).Conclusions: Less leakage was observed when Er,Cr:YSGG cavities were restored withsilorane-based composite resin, using the bulk increment technique. Nevertheless, cavities doneusing diamond bur have less leakage only when incrementally restored.

Benefícios dos lasers de alta e baixa potência no procedimento restaurador direto: relato de caso / Benefits of low and high power lasers on direct restorative procedures: a case report

Lasers de alta e baixa potência têm sido amplamente utilizados em diversas especialidadesda Odontologia. Na Dentística, podem ser utilizados em diferentes etapas do procedimento restaurador direto, como na remoção seletiva do tecido cariado e redução de sensibilidade pós¬preparo cavitário. Este artigo tem como objetivo apresentar um relato de caso em que diferentes lasers foram utilizados e discutir, baseado em resultados de estudos já publicados na literatura, os benefícios de cada um deles quando associados ao procedimento convencional.

High and low power lasers have been widely used in different specialties of Dentistry. InRestorative Dentistry, it can be used in different steps of the direct restorative procedure, as for the selectively remova I of caries tissue and for the reduction of tooth sensitivity following cavity preparation. This article aims to present a case report in which different lasers were used and discuss, based on results of studies already published in the literature, the benefits of each laser when associated with conventional procedures.

Pré-tratamento da superfície de esmalte bovino (Flúor, CPP-ACP, Laser Nd: YAG + Flúor) antes de um clareamento de consultório. Efeitos sobre a morfologia, a microdureza e a cor do esmalte / Pre-treatment of the surface of bovine enamel (fluoride, CPP-ACP, and Nd: YAG laser + fluoride) before an office whitening. Effects on morphology, microhardness and color enamel

o clareamento dental oferece uma opção de tratamento conservador, seguro e eficiente para aqueles pacientes insatisfeitos com a cor dos seus dentes. Entretanto, o baixo pH inicial dos agentes clareadores pode causar perda de estrutura levando à alteração na microdureza e na morfologia do esmalte. O objetivo deste trabalho foi verificar a influência dos pré-tratamentos da superfície de esmalte dental bovino com Flúor, CPP-ACP ou laser de Nd:YAG associado ao flúor realizados 24 horas antes do clareamento de consultório, avaliando-se: a morfologia, a microdureza e a alteração de cor do esmalte dental. Sessenta e quatro incisivos bovinos foram preparados de acordo com a análise para a qual eles foram submetidos. Quatro dentes foram preparados para MEV, vinte dentes para a microdureza e quarenta dentes para a análise de cor. Todos eles tiveram suas raízes removidas a 2 mm do limite amelodentinário e blocos de esmalte foram cortados e depois planificados e polidos com lixas de carbureto de silício de granulação decrescente (#400, 600, 1200 e 4000). Após o polimento, os blocos de esmalte foram submetidos aos pré-tratamentos de superfície com flúor, CPP-ACP e laser de Nd:YAG associado ao flúor e 24 horas depois eles foram clareados com peróxido de hidrogênio a 35% conforme técnica de clareamento de consultório. A avaliação do esmalte dental bovino submetido à ação do clareamento quanto à microdureza e à alteração de cor, foi realizada através do microdurômetro e espectrofotômetro, respectivamente no início e após o clareamento. Uma leitura intermediária foi feita imediatamente após os pré-tratamentos de superfície de esmalte e outra imediatamente após o clareamento. Duas amostras de cada grupo (n=2) foram confeccionadas para a Microscopia Eletrônica de Varredura para observação da morfologia da superfície do esmalte. Quanto à microdureza os seguintes resultados foram encontrados: G1

The bleaching offers a conservative, safe and effective for patients dissatisfied with color of your teeth. However, the low initial pH of bleaching agents can cause loss of structure leading to change in morphology, microhardness of enamel. The aim of this study was to assess the influence of pre-treatments on surface of bovine enamel with fluoride, CPP-ACP or laser Nd: YAG laser associated with fluoride applied 24 h before the whitening, dental evaluating: morphology, microhardness and color change of enamel. Sixty-four bovine incisors were prepared according to analysis for which they were submiUed. Four teeth were prepared for morphologic analysis, twenty teeth were prepared for microhardness and forty teeth were prepared for analyze color change. They ali had their roots removed 2 mm dentinoenamel junction and enamel blocks were cut and then planned and polished with silicon carbide abrasive paper of decreasing grain (# 400, 600, 1200 and 4000). After polishing, the enamel blocks were subjected to surface treatment with fluoride, CPP-ACP and laser Nd: YAG laser associated with fluoride and after 24 h they were bleached with hydrogen peroxide 35% as bleaching technique office. Evaluation of bovine enamel subjected to action of bleaching on microhardness and color change was accomplished through the microhardness tester and spectrophotometer, respectively, before and after bleaching. An intermediate reading was made immediately after the pretreatment of enamel surface. Another reading was made immediately after bleaching. Two especimes of each group (n = 2) were prepared for scanning electron microscopy to morphology of enamel surface. The microhardness of following results were found: G1 - 287.7± 25.78; 279.70 ± 21.04; 206.20 ± 13.14; 242.30 ± 19.28; G2 - 260.90 ± 17.57; 269.40 ± 29.74; 248.80 ± 30.33; 260.40 ± 24.41; G3 - 274.40 ± 38.29; 275.90 ± 33.94; 245.90 ±

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