Liposomal anesthetic gel for pain control during periodontal therapy in adults: a placebo-controlled RCT.

INTRODUCTION: Periodontal therapy usually requires local anesthesia. If effective, a non-invasive, liposomal anesthetic gel could increase the levels of acceptance of patients in relation to periodontal therapy. OBJECTIVE: This study investigated the efficacy of liposomal anesthetic gel for pain control during periodontal therapy. METHODOLOGY: Forty volunteers with moderate to severe chronic periodontitis were recruited, of which at least three sextants required periodontal therapy. At least one of the selected teeth had one site with a probing depth of ≥4 mm. The volunteers received the following three gels: a placebo, lidocaine/prilocaine (Oraqix®), or a liposomal lidocaine/prilocaine, which were applied to different sextants. Pain frequency was registered during treatment and the volunteers received a digital counter to register any painful or uncomfortable experiences. At the end of each session, the volunteers indicated their pain intensity using rating scales (NRS-101 and VRS-4). The volunteers had their hemodynamic parameters measured by a non-invasive digital monitor. RESULTS: Pain frequency/intensity did not show statistical difference between intervention groups. The tested gels did not interfere with the hemodynamic indices. Dental anxiety, suppuration and probing depth could influence pain during periodontal therapy. CONCLUSION: Our results suggest limited indications for the use of non-invasive anesthesia when used for scaling and root planing. Intra-pocket anesthetic gel could be a good option for anxious patients, or those who have a fear of needles.

Liposomal anesthetic gel for pain control during periodontal therapy in adults: a placebo-controlled RCT

Abstract Periodontal therapy usually requires local anesthesia. If effective, a non-invasive, liposomal anesthetic gel could increase the levels of acceptance of patients in relation to periodontal therapy. Objective: This study investigated the efficacy of liposomal anesthetic gel for pain control during periodontal therapy. Methodology: Forty volunteers with moderate to severe chronic periodontitis were recruited, of which at least three sextants required periodontal therapy. At least one of the selected teeth had one site with a probing depth of ≥4 mm. The volunteers received the following three gels: a placebo, lidocaine/prilocaine (Oraqix®), or a liposomal lidocaine/prilocaine, which were applied to different sextants. Pain frequency was registered during treatment and the volunteers received a digital counter to register any painful or uncomfortable experiences. At the end of each session, the volunteers indicated their pain intensity using rating scales (NRS-101 and VRS-4). The volunteers had their hemodynamic parameters measured by a non-invasive digital monitor. Results: Pain frequency/intensity did not show statistical difference between intervention groups. The tested gels did not interfere with the hemodynamic indices. Dental anxiety, suppuration and probing depth could influence pain during periodontal therapy. Conclusion: Our results suggest limited indications for the use of non-invasive anesthesia when used for scaling and root planing. Intra-pocket anesthetic gel could be a good option for anxious patients, or those who have a fear of needles.

Evaluation of several clinical parameters after bleaching with hydrogen peroxide at different concentrations: A randomized clinical trial.

OBJECTIVE: This randomized double-blind clinical trial compared tooth sensitivity (TS), bleaching efficacy, and cytokine levels after applying in-office bleaching treatments containing 15% and 35% hydrogen peroxide (HP15% and HP35%, respectively). METHODS: Twenty-five volunteers were randomly assigned to receive HP15% or HP35% treatment. The bleaching agent was applied in three 15-min applications per session. Two bleaching sessions were separated by a 1-week interval. The participants scored TS using a visual analog scale and numerical rating scale. Bleaching efficacy was determined by subjective and objective methods. Gingival crevicular fluid was collected from three jaws sites per patient for the analysis of fluid volume. Flow cytometry was used to analyze gingival crevicular fluid levels of interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor, and interferon-gamma. All measurements were obtained before and after bleaching. All data were statistically analyzed (α=0.05). RESULTS: The absolute risk and intensity of TS was higher for HP35% than for HP15% (p>0.002). One month post-bleaching, HP35% produced more bleaching than HP15% (p=0.02). However patient perception (p=0.06) and patient satisfaction (p=0.53) with regard to bleaching were not significantly different. No significant differences existed in the gingival fluid volume (p>0.38) or in any cytokine level (p>0.05) for either HP concentration. CONCLUSION: Treatment: with HP35% is more effective than HP15%, but generates a greater risk and intensity of TS. No inflammatory changes occurred despite the difference in the HP concentrations. CLINICAL SIGNIFICANCE: Hydrogen peroxide at a lower concentration (e.g., 15%) should be considered a good treatment alternative for in-office bleaching because the higher concentration for in-office bleaching generates a greater risk and intensity of TS for patients.

Simvastatin modulates gingival cytokine and MMP production in a rat model of ligature-induced periodontitis.

PURPOSE: The aim of this study was to evaluate the effect of simvastatin on the synthesis of cytokines TNF-α and IL-10 and metalloproteinase (MMPs) 2 and 9 in a rat model of ligature-induced periodontitis. MATERIALS AND METHODS: Twenty Wistar rats were used, and a cotton ligature was place in a subgingival position encircling the entire cervix of the first molar of the left (ipsilateral) side of the mandible. The right (contralateral) side of the mandible had no ligature placed and was used as control. After the ligature placement, animals were randomly assigned to two experimental groups (n=10): 1) rats with ligature + vehicle (saline; 10 mL/kg; orally) and 2) rats with ligature + simvastatin (25 mg/kg; orally). After 14 days of treatment, the animals were euthanized by anesthetic overdose and the gingival tissue was removed and homogenized in appropriate buffer. MMP-2 and -9 release as well as the IL-10 and TNF-α levels were detected by enzyme-linked immunosorbent assay. Statistical comparison was performed by unpaired Student's t-test, with p<0.05 representing significance. RESULTS: No differences were observed for TNF-α production between the groups (p>0.05). However, IL-10 was upregulated in simvastatin-treated animals (1.8-fold increase) in comparison with the vehicle-treated group (p<0.05). Simvastatin reduced the gingival levels of MMP-9 (64.3%) in comparison with vehicle-treated samples (p<0.05). CONCLUSION: Oral treatment with simvastatin increased the release of IL-10 and reduced the MMP-9 in ligature-induced periodontitis model in rats.

Evaluation of Bond Strength, Marginal Integrity, and Fracture Strength of Bulk- vs Incrementally-filled Restorations.

PURPOSE: This study evaluated the effect of application technique and preparation size on the fracture strength (FS), microtensile bond strength (µTBS) and marginal integrity (MI) of direct resin composite restorations. MATERIALS AND METHODS: Conservative (5 × 2 × 2 mm) or extended (5 × 4 × 2 mm) preparations below the cementoenamel junction were performed in 140 human maxillary premolars (n = 70 per group). After adhesive application (XP Bond), half of each group was restored with the bulk technique (one 4-mm increment of Surefill SDR Flow plus one 1-mm horizontal capping layer of TPH3 [Spectrum TPH3 resin composite]) and half incrementally (TPH3 in three horizontal incremental layers, 1.5 to 2 mm each), all using a metal matrix band. After storage (24 h at 37°C), the proximal surfaces of each tooth were polished with Sof-Lex disks. For FS measurement, 60 restorations were mounted in a universal testing machine and subjected to a compressive axial load applied parallel to the long axis of the tooth, running at a crosshead speed of 0.5 mm/min. For µTBS testing, 40 teeth were longitudinally sectioned to obtain resin-dentin bonded sticks from the cavity floor (bonded area: 0.8 mm2). Specimens were tested in tension at 0.5 mm/min. The external marginal integrity of both proximal surfaces was analyzed using SEM of epoxy resin replicas. The µTBS, marginal integrity, and fracture resistance data were subjected to two-way ANOVA, and Tukey's post-hoc test was used for pair-wise comparisons (a = 0.05). RESULTS: Fracture resistance, microtensile bond strength, and marginal integrity values were not statistically significantly affected by application technique or preparation size (p = 0.71, p = 0.82, and p = 0.77, respectively). CONCLUSIONS: The use of a bulk-fill flowable composite associated with a conventional resin composite as a final capping layer did not jeopardize the fracture strength, bond strength to dentin, or marginal integrity of posterior restorations.

Relação bidirecional entre doença periodontal e doença pulmonar obstrutiva crônica: revisão de literatura / Bidirectional relationship between periodontal disease and chronic obstructive pulmonary disease ­ literature review

A Doença Periodontal (DP) é caracterizada por apresentar alta prevalência mundial, afetando os tecidos essenciais de suporte e proteção do dente. A DP possui envolvimento de vários mediadores inflamatórios, dentre eles as citocinas, bem como o recrutamento de células de defesa. Durante os últimos 20 anos, muitos estudos sugeriram a atuação da DP como fator de risco para doenças sistêmicas, como a Doença Pulmonar Obstrutiva Crônica (DPOC), tendo um papel fundamental na evolução desta doença pulmonar. A DPOC tem sido registrada como uma das principais causas de morte no mundo. Segundo a OMS a DPOC é uma enfermidade caracterizada pela obstrução crônica do fluxo aéreo, não reversível totalmente. Em muitos estudos foi encontrada uma associação entre DPOC e DP, porém a magnitude e o impacto desta relação ainda não estão bem esclarecidos. Segundo a Federação Européia de Periodontia e a Associação Americana de Periodontia, a inflamação presente na DPOC pode ser alterada em casos de disseminação hematogênica de mediadores inflamatórios e/ou microrganismos presentes nas bolsas periodontais. A partir desta perspectiva o objetivo deste estudo foi revisar a literatura acerca da importância da relação entre DPOC e DP. Concluiu-se que os achados sugerem uma associação de fator de risco entre a doença periodontal e a doença pulmonar obstrutiva crônica e que uma promoção da saúde periodontal em pacientes com DPOC pode ser importante para melhorar a qualidade de vida e prevenir o desenvolvimento e a frequência de exacerbações desta doença pulmonar (AU)

Periodontal disease (PD) is characterized as a worldwide high prevalent disease affecting teeth's support and protection tissues. Several inflammatory mediators, including cytokines, as well as immune cells recruitment are involved in PD. During the last twenty years, many studies have suggested the role of PD as a risk factor for systemic diseases such as Chronic Obstructive Pulmonary Disease (COPD), playing a key role in the evolution of lung disease. COPD has been reported as a major cause of death worldwide. According to the World Health Organization, COPD is a disease characterized by chronic airflow obstruction, not fully reversible. Many studies found an association between COPD and PD, but the magnitude and impact of this relationship are not well understood. According to the European Federation of Periodontology and the American Association of Periodontology, inflammation present in COPD may be changed in cases of hematogenous dissemination of inflammatory mediators and / or microorganisms present in periodontal pockets. From this perspective the aim of this study was to review the literature about the importance of the relationship between COPD and PD. It was concluded that the findings suggest a risk factor association between periodontal disease and chronic obstructive pulmonary disease and that periodontal health promotion in patients with COPD may be important to improve the quality of life and prevent the development and frequency of the pulmonary exacerbations of this disease. (AU)

Toothpaste prevents debonded brackets on erosive enamel.

UNLABELLED: This study evaluated the effect of high fluoride dentifrice on the bond strength of brackets after erosive challenge. Eighty-four enamel specimens were divided into seven groups (n = 12): WN (distilled water/no acid challenge), W3C (distilled water/3 cycles of acid challenge), and W6C (distilled water/6 cycles of acid challenge) were not submitted to dentifrice treatment. Groups RF3C (regular fluoride dentifrice/3 cycles of acid challenge) and RF6C (regular fluoride dentifrice/6 cycles of acid challenge) were treated with dentifrices containing 1450 µg F(-)/g and HF3C (high fluoride dentifrice/3 cycles of acid challenge) and HF6C (high fluoride dentifrice/6 cycles of acid challenge) were with 5000 µg F(-)/g. Acid challenges were performed for seven days. After bond strength test, there was no significant difference among groups submitted to 3 cycles of acid challenge (P > 0.05). Statistically significant difference was found between the regular and high fluoride dentifrices after 6 cycles of acid challenge (<0.05). Similar areas of adhesive remaining were found among control groups and among groups W6C, RF3C, RF6C, HF3C, and HF6C. The high fluoride dentifrice was able to prevent the reduction of bond strength values of brackets submitted to acid challenge. CLINICAL RELEVANCE: the high fluoride toothpaste prevents debonded brackets on erosive enamel.

Antimicrobial effect and transdentinal diffusion of new intracanal formulations containing nitrofurantoin or doxycycline.

The aim of this study was to investigate in vitro the antimicrobial effect and diffusion against E. faecalis of new intracanal medications on the external root surface. The medications tested were a placebo gel (PC); the new formulations with either 3% nitrofurantoin (NIT) or 3% doxycycline hydrochloride (DX) and 2% chlorhexidine (CHX) gel as positive control. The new formulations were tested using the traditional agar diffusion test (ADT) and an adapted agar diffusion method (AADM), where the teeth were filled with the medications and left to diffuse on agar surface seeded with E. faecalis. In the ADT, the larger zones of microbial growth inhibition were seen in DX, followed by CHX and NIT. In the AADM test only DX and CHX showed antimicrobial effect. Statistically significant differences between groups were observed by the Kruskal-Wallis test (2=47.126; p<0.001). The new intracanal formulations with DX and NIT have demonstrated antimicrobial effect against E. faecalis, but only DX was able to diffuse through the dentinal tubules and exert antimicrobial effect outside the roots.

Human dental enamel and dentin structural effects after Er:YAG laser irradiation.

UNLABELLED: Ideally projected to be applied on soft tissues, infrared lasers were improved by restorative dentistry to be used in hard dental tissues cavity preparations--namely enamel and dentin. This paper evidentiates the relevant aspects of infrared Erbium laser's action mechanism and its effects, and characterizes the different effects deriving from the laser's beams emission. The criteria for use and selection of optimal parameters for the correct application of laser systems and influence of supporting factors on the process, such as water amount and its presence in the ablation process, protection exerted by the plasma shielding and structural factors, which are indispensable in dental tissues cavity preparation related to restorative technique, are subordinated to optical modifications caused by the interaction of the energy dissipated by these laser light emission systems in the targeted tissue substrate. CLINICAL RELEVANCE: Differences in the action of infrared Erbium laser system in regard to the nature of the ablation process and variations on the morphological aspects observed in the superficial structure of the target tissue irradiated, may be correlated to the structural optical modifications of the substrate produced by an interaction of the energy propagated by laser systems.

Antimicrobial Effect and Transdentinal Diffusion of New Intracanal Formulations Containing Nitrofurantoin or Doxycycline

The aim of this study was to investigate in vitro the antimicrobial effect and diffusion against E. faecalis of new intracanal medications on the external root surface. The medications tested were a placebo gel (PC); the new formulations with either 3% nitrofurantoin (NIT) or 3% doxycycline hydrochloride (DX) and 2% chlorhexidine (CHX) gel as positive control. The new formulations were tested using the traditional agar diffusion test (ADT) and an adapted agar diffusion method (AADM), where the teeth were filled with the medications and left to diffuse on agar surface seeded with E. faecalis. In the ADT, the larger zones of microbial growth inhibition were seen in DX, followed by CHX and NIT. In the AADM test only DX and CHX showed antimicrobial effect. Statistically significant differences between groups were observed by the Kruskal-Wallis test (2=47.126; p<0.001). The new intracanal formulations with DX and NIT have demonstrated antimicrobial effect against E. faecalis, but only DX was able to diffuse through the dentinal tubules and exert antimicrobial effect outside the roots.

O objetivo deste estudo foi investigar, in vitro, o efeito antibacteriano e a difusão frente ao E. faecalis, de novas medicações intracanal na superfície externa da raiz. As medicações testadas foram um gel placebo (PC), as novas formulações quer com nitrofurantoína a 3% (NIT) ou hidrocloridrato de doxiciclina a 3%(DX) e um gel de clorexidina a 2% (CHX) como controle positive. As novas formulações foram testadas usando o tradicional teste de difusão em agar (ADT) e um método de difusão adaptado (AADM), onde os dentes foram preenchidos com as medicações e deixados a difundir numa superfície de agar semeada com E. faecalis. No ADT, a maior área de inibição foi registada para DX, seguida por CHX e NIT. No teste AADM, apenas DX e CHX demonstraram ação antimicrobiana. Foram observadas diferenças significativas entre os grupos através do teste Kruskal-Wallis (X2=47.126; p<0.001). As novas formulações intracanais contendo DX e NIT demonstraram ação antimicrobiana quando em contacto com E. faecalis, mas apenas DX teve capacidade de difundir através dos túbulos dentinários e exercer ação antimicrobiana fora das raízes.

Characterization of dentifrices containing desensitizing agents, triclosan or whitening agents: EDX and SEM analysis.

Dentifrices with different compositions are available on the market, but there is limited information about their properties. The aim of this in vitro study was to evaluate the physicochemical characteristics of 12 dentifrices divided into three categories, as containing desensitizing agents, Triclosan or whitening agents. Desiccation loss/residue analysis: 5 g of dentifrice was weighed five times for each group. pH analysis: 5 g of dentifrice were diluted in three parts of distilled water and analyzed using a digital potentiometer. Scanning electron microscopy (SEM): analysis of ashes, shape and size of the particles. Energy-dispersive x-ray spectroscopy (EDX): identification of the abrasive elements. Data were analyzed using ANOVA, Bonferroni post hoc test (α=0.05). Desiccation loss: 38.21% to 65.83%. Dentifrices containing Triclosan and desensitizing agents showed statistically significant differences among them (p<0.05). Whitening dentifrices showed statistically significant differences between Close-Up Whitening and Sensodyne Branqueador (44.72%, 65.83%, respectively). Most dentifrices presented neutral or basic pH. Different shape and size particles were observed in the SEM analysis. Abrasive elements were identified in the EDX. These results demonstrate that the evaluated dentifrices had different properties and their composition influences directly their characteristics, thus resulting in a more or less abrasive action on tooth surface. Knowing the characteristics of the dentifrices is important to indicate the ideal product for each case.

New intracanal formulations containing doxycycline or chlorhexidine against Enterococcus faecalis.

The present study aims to evaluate the antimicrobial effect of two new intracanal preparations against E. faecalis. Thirty single-rooted human canine teeth were used. The crowns were removed and the roots were instrumented using a conventional technique. Three groups of ten teeth each were infected with 108 CFU/ ml of E. faecalis for 21 days. The root canals were flled with new intracanal medications containing 3% doxycycline hydrochloride (DX) or 2% chlorhexidine digluconate (CHX). Ten teeth received no medication (NM)-negative control. Microbial samples were obtained 21 days after contamination: 14 days under the effect of the intracanal medications and 7 days after replacing the medications by BHI broth. The samples were homogenized, diluted, seeded on BHI agar and incubated for 48h/36°C. The number of colony forming units (CFU/ml) was obtained and analyzed statistically. All intracanal dressings significantly reduced the number of bacterial cells in the root canal after 14 days with medication. After the period with 7 days with BHI broth, the CFU counts of E. faecalis remained at low values. However, the NM group showed a significant increase of CFU in this period to similar values of the initial contamination. 3% doxycycline hydrochloride gel and 2% CHX gel were effective to eliminate E. faecalis from the root canal system.

Preventive effect of a high fluoride toothpaste and arginine-carbonate toothpaste on dentinal tubules exposure followed by acid challenge: a dentine permeability evaluation.

BACKGROUND: Considering the current high use of high fluoride toothpastes, the aim of the study was to quantify alterations in the root dentine permeability submitted to treatment with a high fluoride toothpaste and 8% arginine, calcium carbonate, sodium monofluorophosphate toothpaste as a preventive treatment for dentinal tubules exposure followed by acid challenge. METHODS: Thirty-third molars were sectioned below the cementoenamel. The root segments were connected to a hydraulic pressure apparatus to measure dentine permeability after the following sequential steps (n = 10 per group): I) Baseline; II) treatment with phosphoric acid for 30 s (maximum permeability); III) Toothbrushing (1 min) according to the experimental groups (G1- control; G2- 5000 ppm fluoride toothpaste; G3- 8% arginine-calcium carbonate toothpaste); IV) acid challenge for 5 min (orange juice). The data were converted into percentage, considering stage II as 100%. RESULTS: The results have shown a statistically significant decreasing on dentine permeability after treatment with toothpaste (Friedman test and Dunn's post hoc test). Comparison among groups demonstrated a high increasing on dentine permeability when acid challenge was performed after toothbrushing with distilled water (control group) (Kruskal-Wallis and Dunn's post hoc test). CONCLUSION: The toothpaste treatment may provide sufficient resistance on dentine surface, preventing dentinal tubules exposure after acid challenge.

Characterization of Dentifrices Containing Desensitizing Agents, Triclosan or Whitening Agents: EDX and SEM Analysis

Dentifrices with different compositions are available on the market, but there is limited information about their properties. The aim of this in vitro study was to evaluate the physicochemical characteristics of 12 dentifrices divided into three categories, as containing desensitizing agents, Triclosan or whitening agents. Desiccation loss/residue analysis: 5 g of dentifrice was weighed five times for each group. pH analysis: 5 g of dentifrice were diluted in three parts of distilled water and analyzed using a digital potentiometer. Scanning electron microscopy (SEM): analysis of ashes, shape and size of the particles. Energy-dispersive x-ray spectroscopy (EDX): identification of the abrasive elements. Data were analyzed using ANOVA, Bonferroni post hoc test (α=0.05). Desiccation loss: 38.21% to 65.83%. Dentifrices containing Triclosan and desensitizing agents showed statistically significant differences among them (p<0.05). Whitening dentifrices showed statistically significant differences between Close-Up Whitening and Sensodyne Branqueador (44.72%, 65.83%, respectively). Most dentifrices presented neutral or basic pH. Different shape and size particles were observed in the SEM analysis. Abrasive elements were identified in the EDX. These results demonstrate that the evaluated dentifrices had different properties and their composition influences directly their characteristics, thus resulting in a more or less abrasive action on tooth surface. Knowing the characteristics of the dentifrices is important to indicate the ideal product for each case.

Dentifrícios com diferentes composições estão disponíveis no mercado, mas existe pouca informação sobre suas propriedades. O objetivo do presente estudo “in vitro” foi avaliar as características físico-químicas de 12 dentifrícios divididos em 3 categorias, como contendo: agentes dessensibilizantes, triclosan ou agentes clareadores. Perda por dessecação/análise de resíduos: 5 g do dentifrício foi pesado cinco vezes para cada grupo. Análise do pH: foram diluídos 5 g do dentifrício suspensos em três partes de água destilada e analisados usando um potenciômetro digital. Microscopia eletrônica de varredura (MEV): análise das cinzas, forma e tamanho de partículas dos agentes abrasivos. Espectroscopia de raios X por dispersão em energia (EDX): identificação dos elementos abrasivos. Análise dos dados: Os dados foram analisados usando ANOVA e teste pos-hoc Bonferroni (α=0,05). Perda por dessecação: 38,21% à 65,83%. Os dentifrícios contendo triclosan e agentes dessensibilizantes mostraram diferença significante entre eles (p<0,05). Dentifrícios clareadores mostraram diferença significante entre Close-Up Whitening e Sensodyne Branqueador (44,72% e 65,83%, respectivamente). A maioria dos dentifrícios apresentaram pH básico ou neutro. Diferentes formas e tamanhos das partículas foram observadas na análise em MEV. Elementos abrasivos foram identificados no EDX. Estes resultados demonstram que os dentifrícios avaliados apresentaram diferentes propriedades e que suas composições influenciam diretamente em características, resultando em ações mais ou menos abrasivas sobre a superfície do dente. O conhecimento sobre as características dos dentifrícios é importante para indicar o produto ideal para cada caso.

In vitro evaluation of Biosilicate® dissolution on dentin surface: a SEM analysis / Avaliação in vitro da dissolução do Biosilicato® sobre a superfície dentinária: análise por meio da microscopia eletrônica de varredura

Introduction: Biomaterials such as bioactive glasses and glass-ceramics have been proposed for the treatment of dentinal hypersensitivity. Objective: to evaluate by scanning electron microscopy (SEM), the dissolution of a novel bioactive glass-ceramic (Biosilicate® 1-20 µm particles) on dentin surface samples, with different application methods and different dilution medium used for applying Biosilicate®. Material and Method: 280 dentin samples were randomly divided into four groups: (1) Biosilicate® plus fluoride gel applied with Robinson brush; (2) Biosilicate® plus fluoride gel applied with microbrush; (3) Biosilicate® plus distilled water applied with Robinson brush; (4) Biosilicate® plus distilled water applied with microbrush. After treatment, the samples were immersed in saliva at different periods (0, 15 and 30 minutes, 1, 2, 12 and 24 hours). Two photomicrographs were obtained from each sample and were further analyzed by a blind calibrated examiner according to a "Particle Dissolution Index" created for this study. Result: The data were analyzed using the Mann-Whitney, Kruskal-Wallis and Dunn's tests. There was no statistical difference among the degrees of dissolution between the 4 groups in any period. Conclusion: Biosilicate® can be incorporated in both substances without differences in the degree of dissolution of the particles in any of the evaluated periods and the application of dentine can be performed with both methods evaluated.

Introdução: Biomateriais, tais como vidros bioativos e vidros cerâmicos têm sido propostos para o tratamento da hipersensibilidade dentinária. Objetivo: Avaliar por microscopia eletrônica de varredura (SEM), a dissolução de uma nova vitrocerâmica bioativa (Biosilicato®, partículas de 1-20 µm) na superfície de amostras de dentina, com diferentes métodos de aplicação e de meio de diluição diferente, usado para aplicação de Biosilicato®. Material e Método: 280 amostras de dentina foram divididas aleatoriamente em quatro grupos: (1) Biosilicato® mais flúor gel aplicado com escova de Robinson, (2) Biosilicato® mais flúor gel aplicado com microbrush, (3) Biosilicato® mais água destilada aplicado com escova de Robinson; (4) Biosilicato® mais água destilada aplicado com microbrush. Após o tratamento, as amostras foram imersas em saliva, em diferentes períodos (0, 30 e 15 minutos, 1, 2, 12 e 24 horas). Duas fotomicrografias foram obtidas a partir de cada amostra e foram analisadas por um examinador calibrado cego de acordo com um "Índice de Dissolução de Partículas", criado para este estudo. Resultado: Os dados foram analisados usando o teste de Mann-Whitney, Kruskal-Wallis e Dunn. Não houve diferença estatística entre os graus de dissolução entre os quatro grupos em qualquer período. Conclusão: Biosilicato® pode ser incorporado em ambas às substâncias, sem diferenças no grau de dissolução das partículas em qualquer dos períodos de avaliação e a aplicação sobre da dentina pode ser realizada com os dois métodos avaliados.

Degree of conversion and hardness of two different systems of the Vitrebond™ glass ionomer cement light cured with blue LED.

This study investigated the physicochemical properties of the new formulation of the glass ionomer cements through hardness test and degree of conversion by infrared spectroscopy (FTIR). Forty specimens (n = 40) were made in a metallic mold (4 mm diameter x 2 mm thickness) with two resin-modified glass ionomer cements, Vitrebond™ and Vitrebond™ Plus (3M/ ESPE). Each specimen was light cured with blue LED with power density of 500 mW/cm(2) during 30 s. Immediately after light curing, 24h, 48h and 7 days the hardness and degree of conversion was determined. The Vickers hardness was performed by the MMT-3 microhardness tester using load of 50 gm force for 30 seconds. For degree of conversion, the specimens were pulverized, pressed with KBr and analyzed with FT-IR (Nexus 470). The statistical analysis of the data by ANOVA showed that the Vitrebond™ and Vitrebond™ Plus were no difference significant between the same storage times (p > 0.05). For degree of conversion, the Vitrebond™ and Vitrebond™ Plus were statistically different in all storage times after light curing. The Vitrebond™ showed higher values than Vitrebond™ Plus (p < 0.05). The performance of Vitrebond™ had greater results for degree of conversion than Vitrebond™ Plus. The correlation between hardness and degree of conversion was no evidence in this study.

Influence of artificial aging in marginal adaptation of mixed class V cavities.

The aim of this study was to investigate whether the artificial aging by thermal cycling had influenced the marginal adaptation of class V restorations with/without chlorhexidine application in the bond process. Twelve intact human third molars were used. Class V cavity preparations were performed on the buccal surface and the teeth received 35% phosphoric acid-etching procedure (Ultradent Products Inc., South Jordan, Utah, USA). Subsequently, the samples were divided in two groups: Untreated acid-etched dentin and chlorhexidine application as an adjunct in the bond process. The adhesive Single Bond 2 (3M ESPE, St. Paul, MN, USA) was used after 2% chlorhexidine application, and the restorations were performed with Filtek™ Z350 XT (3M ESPE) composite resin. The specimens were submitted to artificial aging by thermal cycling with 3,000 cycles. Analyzes were performed on scanning electron microscopy using replicas of marginal adaptation in percentage of continuous margin before and after the artificial aging. The data were analyzed by paired test and the results showed statistically significant differences in the percentage of continuous margin with/without chlorhexidine treatment before and after thermal cycling. This study concluded that the artificial aging by thermal cycling influenced the marginal adaptation of mixed class V composite restorations.

Comparative analysis between three methods of bone estimating age in individuals with down syndrome by mode of the hand and wrist ray.

The wrist and hand region has been the most commonly used for estimating age and osseous development due to the great number of ossification centers. The aim was to determine which method, Tanner & Whitehouse's (TW3), Greulich & Pyle's (GP) or Eklof & Ringertz's, more closely relates to the chronological age in subjects with Down syndrome with chronological ages between 61 and 180 months, using wrist and hand radiographs. The sample consisted of 85 radiographs, 52 of males and 33 of females. Eklof & Ringertz's method was computerized (Radiomemory). Greulich & Pyle's atlas was used and compared with the wrist and hand radiographs. For the TW3 method, 13 ossification centers were evaluated; for each one of them, there are seven or eight development stages to which scores are assigned; these scores are then added and the results are transformed into osseous age values. No statistically significant differences were observed between the male and female genders for methods TW3 and GP, contrasting with the observed differences for the Eklof & Ringertz method. Correlation (r2) between osseous and chronological ages was 0.8262 for TW3 and 0.7965 for GP, while for the method of Eklof & Ringertz, it was 0.7656 for females and 0.8353 for males. The author concluded that the osseous age assessment method that better related to the chronological age was the TW3, followed by Greulich & Pyle's and Eklof & Ringertz's.

Degree of conversion of polymer-matrix composite assessed by FTIR analysis.

AIMS AND OBJECTIVES: The behavior of polymer-matrix composite is dependent on the degree of conversion. The aim of this study was to evaluate the degree of conversion of two resin cements following storage at 37°C immediately, 24 and 48 hours, and 7 days after light-curing by FTIR analysis. MATERIALS AND METHODS: The specimens were made in a metallic mold and cured with blue LED with power density of 500 mW/ cm(2) for 30 seconds. The specimens were pulverized, pressed with KBr and analyzed with FTIR following storage times. STATISTICAL ANALYSIS USED: ANOVA (two-way) and Tukey's post hoc. RESULTS: To the polymer-matrix composites between 24 and 48 hours does not show a significant increase (p > 0.05), however, the highest values were found after 7 days. CONCLUSION: The polymer-matrix composites used in this study showed similarity on the degree of conversion and increased of according to the time of storage.

Influence of nicotine and cotinine impregnation on the first step of periodontal regeneration: clot stabilization.

This study analyzes the clot stabilization on root surfaces of teeth impregnated with cotinine and nicotine and the influence of the scaling in the adhesion of blood components, observing the influence of new exposition to nicotine and/or cotinine after scaling. Fifteen human teeth extracted due to periodontal disease of non-smokers patients were selected and manually scaled. Four dentin blocks were obtained from each tooth (n = 60). Samples received blood application or reimpregnation with nicotine and/or cotinine, depending on the groups. Group 1: PBS immersion + root scaling + blood; group 2: nicotine + root scaling + blood; group 3: nicotine + root scaling + nicotine reapplication + blood; group 4: cotinine + root scaling + blood; group 5: cotinine + root scaling + cotinine reapplication+ blood; group 6: nicotine and cotinine + root scaling + nicotine and cotinine + blood. Samples were kept in 2 ml of each substance for 24 hours. Each group received a blood drop and was analyzed by SEM. The higher amount of blood components was present in teeth exposed to cotinine and the groups submitted to scaling and blood application in comparison with groups that received reapplication of toxic substances after scaling. The greater toxic effect on root dentin surface was after the exposure to nicotine and cotinine. Results suggest that periodontal healing may be delayed in smokers due to the direct inhibition of clot stabilization on the root surface when nicotine and cotinine are present concomitantly.