Influence of Different Surface Treatments on the Bond Strength of Yttria-Stabilized Tetragonal Zirconia Ceramic.

Objective: This in vitro study evaluates the shear bond strength (SBS) of yttria-stabilized tetragonal zirconia (Y-TZP) and resin cement after different surface treatments. Materials and methods: Forty-eight ceramic cubes were divided into four groups (n = 12): G1 (control) sandblasting with Al2O3; G2-sandblasting with silica-coated Al2O3 (Rocatec); G3-Rocatec + CO2 laser; and G4-CO2 laser + Rocatec. A metallic primer was applied to the pretreated ceramic. A rubber ring was adapted on the central area, and then, the resin cement was inserted into the matrix and photoactivated. The samples were evaluated regarding surface roughness (Ra), SBS, failure type, and qualitatively with scanning electron microscopy (SEM). The data were analyzed by one-way analysis of variance followed by Tukey's test (p < 0.05). Results: The mean values of Ra (µm) were as follows: G1-4.52a, G2-4.24a,b, G3-4.10a,b, and G4-2.90b and the mean values of SBS (MPa) were as follows: G1-7.84a , G2-4.41b , G3-4.61b and G4-6.14a,b. SEM analyses showed superficial irregularities for all groups, being more prominent for G1. The presence of silica deposits was observed for G2, G3, and G4, but in the last two groups there were some linear areas, promoted by the fusion of silica, due to the thermomechanical action of the CO2 laser. Conclusions: The surface treatment with CO2 laser + Rocatec, using one MDP-based cement, can be an alternative protocol for the adhesion cementation of Y-TZP ceramic since it was as effective as the conventional pretreatment with aluminum oxide sandblasting.

Cárie de radiação: efeitos da radioterapia na estrutura dentária / Caries de radiación: efectos de la radiación en la estructura dental / Radiation caries: effects of radiotherapy on dental structure

Introdução: Pacientes submetidos à radioterapia para tratamento de neoplasias malignas na região de cabeça e pescoço são propensos a desenvolver complicações orais como a cárie de radiação, que evolui rapidamente e é altamente destrutiva.É reconhecido que o seu desenvolvimento está associado a alterações pós-radioterápicas nas glândulas salivares maiores, o que resulta em hipossalivação e alteração nos constituintes salivares. No entanto, tem sido aceito que danos diretos causados pela radiação à estrutura dentária podem acelerar a progressão da cárie e estudos têm demonstrado alterações morfológicas e físicas em dentes humanos após radioterapia. Objetivo: Propõe-se apresentar um caso de cárie de radiação e os efeitos diretos da radioterapia na estrutura dentária. Relato de caso: Paciente masculino, 60 anos de idade, com queixa principal de fragilidade dentária; relatou história de carcinoma epidermóide em língua há 18 meses e que o protocolo de tratamento aplicado foi quimioterapia (38 sessões), radioterapia (38 sessões) e cirurgia. Ao exame físico, dentre as alterações observadas, destacou-se a presença de regiões cervicais dentárias enegrecidas com coroas bastante fragilizadas em todos os dentes remanescentes, características de cárie de radiação. Foi realizado um tratamento atraumático, que está em acompanhamento. Conclusões: A cárie de radiação tem como principal fator etiológico alterações salivares qualitativas e quantitativas. A discussão sobre os efeitos diretos da radioterapia sobre a estrutura dentária ainda é bastante polêmica na literatura odontológica. Desta forma, sugere-se que mais estudos sejam realizados de forma sistemática, de maneira mais completa e padronizada(AU)

Introducción: Los pacientes sometidos a radioterapia para el tratamiento de tumores malignos en la cabeza y el cuello son propensos a desarrollar complicaciones bucales, tales como caries de radiación que evoluciona rápidamente y es altamente destructiva. Se reconoce que el desarrollo se asocia con cambios posradioterapia en las glándulas salivales, que resulta en hiposalivación y el cambio en los componentes salivales. Sin embargo, se ha aceptado que los daños por radiación directa a la estructura dental puede acelerar la progresión de la caries y los estudios han demostrado cambios morfológicos y físicos en los dientes humanos después de la radioterapia. Objetivo: presentar un caso de caries de radiación y los efectos directos de la radiación en la estructura dental. Presentación del caso: Paciente masculino de 60 años de edad, se quejaba de fragilidad dental, con historia notificada de carcinoma de células escamosas en la lengua hace 18 meses y con protocolo de tratamiento aplicado de quimioterapia (38 sesiones), terapia de radiación (38 sesiones) y cirugía. En el examen físico, de los cambios observados, se destacó la presencia de regiones cervicales dentarias negruzcas con coronas bastante frágiles en todos los dientes restantes, características de caries de radiación. El tratamiento atraumático se realizó y el paciente está bajo observación. Conclusiones: los cambios cuantitativos y cualitativos salivales actúa como el factor causal principal de la caries por radiación. La discusión acerca de los efectos directos de la radiación sobre la estructura del diente es todavía muy controvertido en la literatura dental. Por lo tanto, se sugiere que se realicen estudios adicionales de manera sistemática, más completa y estandarizada(AU)

Introduction: Patients undergoing radiotherapy as treatment for malignant head and neck tumors are prone to develop oral complications such as radiation caries, which evolves rapidly and is highly destructive. Such development is known to be caused by post-radiotherapy alterations in salivary glands resulting in hyposalivation and changes in salivary components. However, it has been accepted that damage by direct radiation to the dental structure may hasten the progress of caries development, and studies have shown the morphological and physical changes occurring in human teeth after radiotherapy. Objective: Present a case of radiation caries and the direct effects of radiation on dental structure. Case presentation: A 60-year-old male patient complains of dental fragility. The patient was diagnosed with squamous-cell carcinoma of the tongue 18 months ago and indicated chemotherapy (38 sessions), radiotherapy (38 sessions) and surgery. Physical examination revealed among other changes the presence of blackish cervical areas with quite fragile crowns in all remaining teeth, which are characteristic of radiation caries. Non-traumatic treatment was performed and the patient is now under observation. Conclusions: Salivary quantitative and qualitative changes are the main cause of radiation caries. Discussion about the direct effects of radiation on dental structure is still quite controversial in the literature on the topic. It is therefore suggested to conduct further studies in a more systematic, complete and standardized manner(AU)

Cárie de radiação: efeitos da radioterapia na estrutura dentária / Caries de radiación: efectos de la radiación en la estructura dental / Radiation caries: effects of radiotherapy on dental structure

Introdução: Pacientes submetidos à radioterapia para tratamento de neoplasias malignas na região de cabeça e pescoço são propensos a desenvolver complicações orais como a cárie de radiação, que evolui rapidamente e é altamente destrutiva.É reconhecido que o seu desenvolvimento está associado a alterações pós-radioterápicas nas glândulas salivares maiores, o que resulta em hipossalivação e alteração nos constituintes salivares. No entanto, tem sido aceito que danos diretos causados pela radiação à estrutura dentária podem acelerar a progressão da cárie e estudos têm demonstrado alterações morfológicas e físicas em dentes humanos após radioterapia. Objetivo: Propõe-se apresentar um caso de cárie de radiação e os efeitos diretos da radioterapia na estrutura dentária. Relato de caso: Paciente masculino, 60 anos de idade, com queixa principal de fragilidade dentária; relatou história de carcinoma epidermóide em língua há 18 meses e que o protocolo de tratamento aplicado foi quimioterapia (38 sessões), radioterapia (38 sessões) e cirurgia. Ao exame físico, dentre as alterações observadas, destacou-se a presença de regiões cervicais dentárias enegrecidas com coroas bastante fragilizadas em todos os dentes remanescentes, características de cárie de radiação. Foi realizado um tratamento atraumático, que está em acompanhamento. Conclusões: A cárie de radiação tem como principal fator etiológico alterações salivares qualitativas e quantitativas. A discussão sobre os efeitos diretos da radioterapia sobre a estrutura dentária ainda é bastante polêmica na literatura odontológica. Desta forma, sugere-se que mais estudos sejam realizados de forma sistemática, de maneira mais completa e padronizada(AU)

Introducción: Los pacientes sometidos a radioterapia para el tratamiento de tumores malignos en la cabeza y el cuello son propensos a desarrollar complicaciones bucales, tales como caries de radiación que evoluciona rápidamente y es altamente destructiva. Se reconoce que el desarrollo se asocia con cambios posradioterapia en las glándulas salivales, que resulta en hiposalivación y el cambio en los componentes salivales. Sin embargo, se ha aceptado que los daños por radiación directa a la estructura dental puede acelerar la progresión de la caries y los estudios han demostrado cambios morfológicos y físicos en los dientes humanos después de la radioterapia. Objetivo: presentar un caso de caries de radiación y los efectos directos de la radiación en la estructura dental. Presentación del caso: Paciente masculino de 60 años de edad, se quejaba de fragilidad dental, con historia notificada de carcinoma de células escamosas en la lengua hace 18 meses y con protocolo de tratamiento aplicado de quimioterapia (38 sesiones), terapia de radiación (38 sesiones) y cirugía. En el examen físico, de los cambios observados, se destacó la presencia de regiones cervicales dentarias negruzcas con coronas bastante frágiles en todos los dientes restantes, características de caries de radiación. El tratamiento atraumático se realizó y el paciente está bajo observación. Conclusiones: los cambios cuantitativos y cualitativos salivales actúa como el factor causal principal de la caries por radiación. La discusión acerca de los efectos directos de la radiación sobre la estructura del diente es todavía muy controvertido en la literatura dental. Por lo tanto, se sugiere que se realicen estudios adicionales de manera sistemática, más completa y estandarizada(AU)

Introduction: Patients undergoing radiotherapy as treatment for malignant head and neck tumors are prone to develop oral complications such as radiation caries, which evolves rapidly and is highly destructive. Such development is known to be caused by post-radiotherapy alterations in salivary glands resulting in hyposalivation and changes in salivary components. However, it has been accepted that damage by direct radiation to the dental structure may hasten the progress of caries development, and studies have shown the morphological and physical changes occurring in human teeth after radiotherapy. Objective: Present a case of radiation caries and the direct effects of radiation on dental structure. Case presentation: A 60-year-old male patient complains of dental fragility. The patient was diagnosed with squamous-cell carcinoma of the tongue 18 months ago and indicated chemotherapy (38 sessions), radiotherapy (38 sessions) and surgery. Physical examination revealed among other changes the presence of blackish cervical areas with quite fragile crowns in all remaining teeth, which are characteristic of radiation caries. Non-traumatic treatment was performed and the patient is now under observation. Conclusions: Salivary quantitative and qualitative changes are the main cause of radiation caries. Discussion about the direct effects of radiation on dental structure is still quite controversial in the literature on the topic. It is therefore suggested to conduct further studies in a more systematic, complete and standardized manner(AU)

Uso de elastômero para delimitação do término do preparo em modelos odontológicos / Use of elastomer for delimitation of the preparation terminal edge in dental models

A comunicação entre o dentista e o técnico de prótese dentária é fundamental para o tratamento. A técnica convencional de troquelização de modelos consiste em sua individualização na região dos preparos através do recorte e eliminação do gesso fora do espaço correspondente ao sulco gengival na região do término. O objetivo deste artigo é descrever dois casos clínicos nos quais foi utilizada uma técnica inovadora de troquelização de modelos.

Communication between the dentist and the dental prosthesis technician is fundamental for treatments. The conventional technique of die casting models consists of their individualization in the preparations region, through plaster cutting and elimination outside the space corresponding to the gingival sulcus in the terminal region. The aim of this article is to describe two clinical cases in which an innovative technique of die casting models was used.

Doenças periodontais em pacientes hivpositivos: uma revisão da literatura / Periodontal disease in HIV-positive patients: a literature review

Many papers indicate that up to 80% of HIV seropositive patients show lesions due to opportunistic infections or malignant neoplasm in oral cavity. Periodontal Diseases (PD) are among the most common oral manifestations in those patients. The aim was to describe the prevalence, the microbiologic characteristics and the clinical forms of PD in HIV seropositive patients. Consultations were conducted in scientific papers on the Virtual Health Library (Biblioteca Virtual em Saúde) - BVS database, from 2007, following selection criteria. The data from the researches varies considerably due to the lack of standardized diagnosis criteria and the methods used. Opportunistic microorganisms usually not related to periodontopathy are frequently found in HIV seropositive patients' oral cavity of and may be related to the rapid progression and severity of the PD in these individuals. The Linear Gingival Erythema (LGE) and the most aggressive and unusual forms of PD, such as Necrotizing Ulcerative Gingivitis (NUG), Necrotizing Ulcerative Periodontitis (NUP) and Necrotizing Ulcerative Stomatitis (NUS), are strongly associated to HIV infection and AIDS. Some authors link the possibility of preexisting PD progress after the HIV infection. The periodontal diseases seem to be linked to HIV infection and AIDS, and can be an important variable in diagnosis and prognosis of these systemic conditions. However, the available researches are not conclusive and there is a need for further studies, with standardized materials and methods, in order to improve the understanding on the mechanisms involved in the association of those pathologies. (AU)

Muitos estudos apontam que até 80% dos indivíduos HIV-positivos apresentam alterações provenientes de infecções oportunistas ou de neoplasia maligna na região da boca e, as Doenças Periodontais (DP) estão entre as mais frequentes manifestações orais nestes pacientes. Objetiva-se descrever a prevalência, as características microbiológicas e as formas clínicas das DP em pacientes HIV-positivos. Foram realizadas consultas em artigos científicos no banco de dados da Biblioteca Virtual em Saúde ­ BVS (a partir de 2007), seguindo critérios de seleção. Os dados de estudos têm variado consideravelmente, devido à falta de padronização nos critérios de diagnóstico e aos métodos utilizados. Microrganismos oportunistas usualmente não relacionados às periodontopatias são encontrados com frequência na cavidade oral de pacientes infectados por HIV e podem relacionar-se à rápida progressão e severidade das DP nestes indivíduos. O Eritema Gengival Linear (EGL) e formas mais agressivas e incomuns das DP, como Gengivite Ulcerativa Necrosante (GUN), Periodontite Ulcerativa Necrosante (PUN) e Estomatite Ulcerativa Necrosante (EUN), estão mais fortemente associadas à infecção por HIV e à AIDS. Alguns autores apontam a possibilidade de progressão das DP pré- existentes após infecção por HIV. Conclui-se que as doenças periodontais parecem apresentar relação com a infecção por HIV e AIDS, podendo ser uma importante variável no diagnóstico e prognóstico destas condições. No entanto, os trabalhos disponíveis atualmente não são conclusivos e, portanto, se fazem necessários novos estudos, com materiais e métodos padronizados, para uma melhor compreensão dos mecanismos envolvidos na associação entre estas patologias (AU)

Five second photoactivation? A microhardness and marginal adaptation in vitro study in composite resin restorations.

INTRODUCTION: Studies defining the characteristics of light curing units and photoactivation methods are necessary to allow the correct choices to be made in daily practice. This study aimed to determine whether different photoactivation protocols for composite resins [periodic level shifting (PLS) - 5 second and soft-start] are able to maintain or enhance the mechanical properties and marginal adaptation of restorations. METHODS: Restorations were placed in bovine teeth using the following photoactivation methods: continuous light for 20 seconds (control group); PLS technology (PLS - 5 second group); and continuous light and a light guide tip distance of 6 mm after which the tip was placed at the surface of the restoration (soft-start group). The teeth were transversely sectioned in the incisal-cervical direction. Thirty halves were randomly selected for Knoop microhardness testing (n = 10). The other 30 halves were subjected to scanning electron microscopy analysis. The images obtained were measured to identify the highest marginal gap, and statistical tests for variance analysis were conducted. RESULTS: Microhardness tests showed no statistically significant difference between the photoactivation methods analysed (P ≥ 0.01). The tests showed a difference among depths (P < 0.01), with the deeper layers being the hardest. In analysing marginal adaptation, no significant difference was identified between the higher marginal gap values in the continuous (mean = 10.36) and PLS - 5 second (mean = 10.62) groups, and the soft-start group (mean = 5.83) presented the lowest values (P < 0.01). CONCLUSIONS: The PLS - 5 second and soft-start protocols did not alter the hardness of the restorations. Moreover, the PLS - 5 second protocol did not alter the marginal adaptation, whereas the soft-start protocol improved marginal adaptation.

Laser Therapy in the Treatment of Paresthesia: A Retrospective Study of 125 Clinical Cases.

OBJECTIVE: The aim of this retrospective study was to evaluate the effectiveness of laser therapy for acceleration and recovery of nerve sensitivity after orthognathic or minor oral surgeries, by analysis of clinical records of patients treated at the Special Laboratory of Lasers in Dentistry (LELO, School of Dentistry, University of São Paulo), throughout the period 2007-2013. BACKGROUND DATA: Nerve tissue lesions may occur during various dental and routine surgical procedures, resulting in paresthesia. Laser therapy has been shown to be able to accelerate and enhance the regeneration of the affected nerve tissue; however, there are few studies in the literature that evaluate the effects of treatment with low-power laser on neural changes after orthognathic or minor oral surgeries. METHODS: A total of 125 clinical records were included, and the data on gender, age, origin of the lesion, nerve, interval between surgery and onset of laser therapy, frequency of laser irradiation (one or two times per week), final evolution, and if there was a need to change the irradiation protocol, were all recorded. These data were related to the recovery of sensitivity in the affected nerve area. Descriptive analyses and modeling for analysis of categorical data (α=5%) were performed. RESULTS: The results from both analyses showed that the recovery of sensitivity was correlated with patient age (p=0.015) and interval between surgery and onset of laser therapy (p=0.002). CONCLUSIONS: Within the limits of this retrospective study, it was found that low- power laser therapy with beam emission band in the infrared spectrum (808 nm) can positively affect the recovery of sensitivity after orthognathic or minor oral surgeries.

A nanodureza e o módulo de elasticidade versus resistência de união da resina com a dentina / The nanohardness and elastic modulus versus bond strength of resin to dentin

Objetivo: Avaliar a nanodureza (Nn) e o módulo de elasticidade (ME) da região de adesão quando utilizados diferentes sistemas adesivos e correlacionar com a resistência adesiva (RA) à dentina. Método: Foram medidos a nanodureza e o módulo de elasticidade da resina composta junto à área de união, da camada de adesivo (Ad), da camada híbrida (Ch), e da dentina adjacente utilizando testes de nanoendentação. Quarenta molares (n=10) foram preparados de modo a obterem-se superfícies planas em dentina, sobre as quais os sistemas adesivos foram aplicados (Adper Scotchbond Multiuso, Adper Single Bond 2, Adper SE Plus e Clearfil SE Bond). Sobre essas superfícies foi inserida a resina composta. Os dentes restaurados foram seccionados para obterem-se corpos-de-prova com área aderida de 1mm2. Um palito de cada dente foi selecionado para análise da nanodureza e do módulo de elasticidade da interface adesiva. Os demais tiveram a resistência de união testada através do teste de microtração. Resultados: O teste ANOVA detectou diferença estatística entre todos os grupos, exceto para a variável nanodureza da camada híbrida. O teste de correlação de Pearson detectou significância para o módulo de elasticidade. Conclusões: Pôde-se concluir que as propriedades mecânicas (resistência adesiva, módulo de elasticidade e nanodureza do sistema adesivo e da camada híbrida) variam dependendo do sistema adesivo. Quanto maior o módulo de elasticidade da camada híbrida de um sistema adesivo maior é sua resistência adesiva e menor o módulo de elasticidade da camada de adesivo. Pôde observar que não houve correlação entre nanodureza e a resistência adesiva.

To evaluate the nanohardness (Nn) and the modulus of elasticity (ME) in the region of adhesion when used different adhesive systems and correlate with the bond strength to dentin (RA). We measured the nanohardness and the modulus of elasticity of the resin composed with the area of bond of the adhesive layer (Ad), hybrid layer (Ch) and adjacent dentin using nanodentition tests. Forty molars (n = 10) were prepared in order to obtain flat dentin surfaces on which the adhesive systems were applied (Adper Scotchbond Multipurpose, Single Bond 2, Adper SE Plus and Clearfil SE Bond). On these surfaces was inserted a composite resin. The restored teeth were sectioned to obtain body-of-proof with adhered area of 1mm2. A stick of each teeth was selected for the nanohardness analysis and the modulus of elasticity of the adhesive interface. The others had the bond strength tested using the microtensile test. The ANOVA detected statistical difference between all groups, except for the variable nanohardness of the hybrid layer. The Pearson’s correlation test found significance for the modulus of elasticity. It was concluded that the mechanical properties (bond strength, the modulus of elasticity and nanohardness of the adhesive system and the hybrid layer) vary depending on the adhesive system. The higher the modulus of elasticity of the hybrid layer of an adhesive system a greater adhesive strength will be and lower the modulus of elasticity of the adhesive layer. It can be observed that there was no correlation between nanohardness and bond strength.

Extração de incisivo inferior combinada à técnica ortodôntica lingual – relato de caso / Lower incisor extraction combined with lingual orthodontics – case report

O tratamento ortodôntico com planejamento de extração do incisivo inferior oferece vantagens como a manutenção do perfil harmônico e resultados mais estáveis na região anterior, além de ser uma alternativa mais conservadora em relação à indicação de extrações de quatro pré-molares. Por outro lado, a técnica ortodôntica lingual destaca-se quando a estética e a discrição durante a fase corretiva do tratamento são prioridades, pois os bráquetes são posicionados atrás dos dentes de maneira a ficarem imperceptíveis. O objetivo deste trabalho é de relatar um caso clínico no qual a correção ortodôntica foi realizada por meio da Ortodontia Lingual e a mecânica foi planejada com extração do incisivo inferior, obtendo-se resultados satisfatórios e estáveis em termos estéticos e funcionais...

Orthodontic treatment with lower incisor extraction planning offers advantages such as preservation of a harmonic profile, and more stable results in the anterior area, being a conservative alternative for the extraction of 4 premolars. On the other hand, lingual orthodontic stands out when aesthetics and discretion are a priority, because the brackets are positioned behind the teeth, and therefore are imperceptible. The aim of this paper was to report a clinical case of orthodontic treatment using lingual orthodontics technique with mechanics planned through lower incisor extraction, reaching satisfactory and stable results for both aesthetics and function...

Shear bond strength of metallic brackets: an in vitro study

To evaluate in vitro the shear bond strength of metallic brackets.Material and Methods:Forty premolars were divided into four groups (n = 10) according to the type of brackets used (G1: Morelli® Light; G2: Morelli® Standard; G3: Morelli® Max; G4: Abzil® Agile). For bonding, Transbond XT® (3M Unitek) resin was used in all groups. Teeth were embedded in ¾ inch PVC tubes with special plaster stone, perpendicular to the ground. Brackets were fixed on the geometric centers of the exposed crowns. After bonding, teeth were stored in distilled water, incubated at 37ºC for 24 hours and submitted to 500 thermal cycles for 30 seconds in each bath (5°C and 55°C), respectively. The bond strength test was performed on the Instron® mechanical testing machine with 3kg load cell at speed of 0.5mm/min. Data were submitted to statistical analysis through the Statistica® software, version 5.0, by Kruscal Wallis test, ANOVA and Tukey (p< 0.05).Results:There was no statistically significant difference in the ARI scores; whereas for shear resistance, this difference was significant (Averages: G1 -Light: 17.53MPa; G2 -Standard: 18.11MPa; G3 -Max: 29.33MPa; G4 -Agile: 11.37MPa) and G3 showed better performance, compared to the others. All other groups showed similar behavior among themselves. Conclusion:Max bracket had the highest shear strength. Further studies should be conducted to investigate the meshes of brackets tested in this study...

Effect of CO2 laser on root caries inhibition around composite restorations: an in vitro study.

The aim of the present study was to investigate the in vitro effect of CO2 laser on the inhibition of root surface demineralization around composite resin restorations. For this purpose, 30 blocks obtained from human molar roots were divided into three groups: group 1 (negative control), cavity prepared with cylindrical diamond bur + acid etching + adhesive + composite resin restoration; group 2, cavity prepared with cylindrical diamond bur + CO2 laser (5.0 J/cm(2)) + acid etching + adhesive + composite resin; and group 3, cavity prepared with cylindrical diamond bur + CO2 laser (6.0 J/cm(2)) + acid etching + adhesive + composite resin. After this procedure, the blocks were submitted to thermal and pH cycling. Root surface demineralization around the restorations was measured by microhardness analysis. The hardness results of the longitudinally sectioned root surface were converted into percentage of mineral volume, which was used to calculate the mineral loss delta Z (ΔZ). The percentage of mineral volume, ΔZ, and the percentage of demineralization inhibition of the groups were statistically analyzed by using analysis of variance and Tukey-Kramer test. The percentage of mineral volume was higher in the irradiated groups up to 80 µm deep. The ΔZ was significantly lower in the irradiated groups than in the control group. The percentage of reduction in demineralization ranged from 19.73 to 29.21 in position 1 (50 µm), and from 24.76 to 26.73 in position 2 (100 µm), when using 6 and 5 J/cm(2), respectively. The CO2 laser was effective in inhibiting root demineralization around composite resin restorations.

Influência do óxido de alumínio na colagem dos bráquetes linguais / The influence of the aluminun oxide on lingual brackets bonding

A descolagem acidental do bráquete é uma severa complicação no decorrer do tratamento ortodôntico, especialmente quando o tratamento é feito com bráquetes linguais. A força de adesão entre o bráquete e o dente é um importante requisito para o sucesso da Ortodontia Lingual na prática diária do consultório. O presente estudo analisou a influência do jateamento do óxido de alumínio na superfície lingual dos dentes antes do condicionamento do esmalte na colagem indireta do aparelho lingual. A força de cisalhamento foi medida 24 horas após a colagem dos bráquetes. Os dentes foram divididos em quatro grupos: G1 - 10 pré-molares com bráquetes da marca American Orthodontics com condicionamento de ácido ortofosfórico a 37%; G2 - 10 pré-molares com bráquetes da marca American Orthodontics com aplicação do jato de óxido de alumínio e ácido ortofosfórico a 37% no esmalte; G3 - 10 pré-molares com bráquetes da marca Ormco com condicionamento de ácido ortofosfórico a 37% e G4 - 10 pré-molares com bráquetes da marca Ormco com aplicação do jato de óxido de alumínio e ácido ortofosfórico a 37% no esmalte. Avaliou-se a resistência ao cisalhamento e observou-se que não ocorreu diferença estatisticamente significante entre os grupos quanto aos diferentes modos de preparo de esmalte. Com relação às marcas comerciais, os bráquetes da American Orthodontics apresentaram resistência à descolagem maior do que os bráquetes da marca Ormco. Concluindo, a resistência à descolagem dos bráquetes não foi aumentada com a aplicação prévia do jato de óxido de alumínio no esmalte hígido, nas duas marcas comerciais de bráquetes.

Accidental bracket debonding is a severe complication throughout orthodontic treatment, especially when using lingual brackets. The bond strength between the bracket and the tooth is an important requirement for the success of Lingual Orthodontics. This study has analyzed the influence of aluminum oxide blasting on the lingual surface of the teeth, before conditioning of the enamel, over indirect bonding of the lingual brace. Shear strength was measured 24 hours after brackets bonding. Teeth were divided into four groups: G1 - 10 premolar teeth with American Orthodontics brackets and 37% orthophosphoric acid conditioning; G2 - 10 premolar teeth with American Orthodontics brackets and application of aluminum oxide and 37% orthophosphoric acid blasting on the enamel; G3 - 10 premolar teeth with Ormco brackets and 37% orthophosphoric acid conditioning; G4 - 10 premolar teeth with Ormco brackets, application of aluminum oxide and 37% orthophosphoric acid blasting on the enamel. When evaluating the shear resistance through mechanical assay, it was not observed statistically significant difference between the groups regarding different enamel preparation modes. Concerning the different commercial brands, the American Orthodontics brackets showed higher debonding resistance than the Ormco brackets. It was concluded that, for both brands of brackets, the resistance to bracket debonding did not increase with the previous application of aluminum oxide blasting on the ename.

Ortodontia Lingual em dentes com comprometimento periodontal - relato de caso / Lingual Orthodontics on teeth with periodontal disease - case report

Devido ao aumento da expectativa de vida na população, um maior número de pacientes adultos tem procurado tratamento ortodôntico com objetivo estético e funcional. A apresentação deste caso clínico aborda as características do tratamento ortodôntico no paciente adulto com comprometimento periodontal. Neste tipo de abordagem deve ser ressaltada a importância do controle de enfermidades sistêmicas, uso de medicamentos, condição da saúde bucal, quantidade de osso alveolar, motivação do paciente e estabilidade oclusal após a terapia ortodôntica. A movimentação ortodôntica com aparatologia fixa lingual representa uma intervenção viável no paciente adulto, desde que realizado com forças ortodônticas leves, respeitando as condições periodontais e considerando as limitações de cada caso.

Due to the increase in life expectancy a greater number of adult patients have sought orthodontic treatment with aesthetic and functional objectives. The presentation of this clinical case report discusses the characteristics of orthodontic treatment in adult patients with periodontal involvement. In this approach, the control of the presence of systemic diseases, medication use, the oral health, amount of alveolar bone, the patient’s motivation, and occlusal stability should be emphasized after orthodontic therapy. Orthodontic movement with fixed lingual appliance represents a viable intervention in adult patients, since it is performed with light orthodontic forces, respecting periodontal conditions and considering the limitations of each case.

Immediate and short-term effects of in-office desensitizing treatments for dentinal tubule occlusion.

OBJECTIVE: The objective of this in vitro study was to evaluate the immediate and short-term effects of laser neodymium-doped yttrium aluminum garnet (Nd:YAG) irradiation and in-office desensitizing treatment on dentin tubule occlusion. BACKGROUND DATA: Literature shows a lack of long-lasting treatments for dentin hypersensitivity. METHODS: Forty-eight dentin slabs (4×4×2 mm) were ground flat, polished, and treated with 27% ethylenediaminetetraacetic acid (EDTA) to open the dentinal tubules. Specimens were randomly divided into the following experimental groups (n=12): Group 1: Control (no treatment); Group 2: Nd:YAG laser irradiation (100 mJ, 85 J/cm(2) per pulse with a quartz fiber of 400 µm, in scanning movements); Group 3: In-office prophylaxis with pumice; Group 4: In-office Colgate Sensitive Pro-Relief™ Desensitizing Paste. Treatments were performed according to the manufacturer's instructions. After treatment, the specimens were submitted to a sequence of erosive and abrasive challenges, twice a day for 5 days. The specimens were qualitatively and quantitatively evaluated by scanning electron microscopy immediately after treatment and after 4 and 5 days. The response variable was the amount of occluded dentin tubules per area, determined by three different examiners with the use of visual criteria, with a standardized grade created in the PowerPoint program. Data were compared with ANOVA and Tukey's test, considering a 5% significance level. RESULTS: Immediately after treatment, a reduction in the number of opened dentin tubules was observed for the laser group when compared with the control group (p<0.05). After the experimental procedures, there were no quantitative differences between the amount of opened dentin tubules for all groups; however, micrographs showed some qualitative tubule occlusion for the laser group after the erosive/abrasive challenge. CONCLUSIONS: only laser irradiation was capable of immediately sealing the dentinal tubules; however, none of the treatments showed efficacy in maintaining tubule occlusion after the chemical and mechanical challenges.

Efeito da redução da intensidade de luz inicial na polimerização de uma resina composta fotoativada com luz halógena e distanciamento da ponta ativadora / Effect of the reduction of the initial light intensity on the polymerization of a composite resin photoactivated with halogen light and distancing of the activator point

Os objetivos deste estudo foram avaliar a dureza de uma resina composta fotoativada pelo método contínuo e compará-la com metodologias que utilizam menor intensidade de luz inicial, seguida pela intensidade máxima. Foram realizados 60 corpos de prova divididos em seis grupos.Os corpos de prova foram confeccionados a partir das matrizes de polipropileno pretas, utilizando a resina composta Z350 (3 M ESPE, Saint Paul, Estados Unidos), e ativadas com o fotoativador Degulus SoftStar 9DEGUSSA-HULS, Hanau, Alemanha). Os corpos de prova foram submetidos ao teste de microdureza Vickers, com o microdurômetro HMV-2000(SHIMADZU, kYOTO, JAPÃO), nas superfícies irradiadas e opostas, sendo comparadas as espessuras e os métodos de fotoativação utilizados. Após os testes de análise de variância e de Tukey, observou-se diferença estatisticamente significante entre os grupos controle, soft-star e variação da distância. A porcentagem de dureza máxima foi considerada aceitável ( menos do que 80 por cento) na superfície irradiada e em profundidades de 1 mm daquela oposta, porém nas de 2 mm os valores não atingiram o mínimo de 80 por cento da dureza máxima. Concluiu-se que os métodos de fotoativação progressiva diminuiram a microdureza da resina composta, quando comparados aos convencionais, sendo isso aceitável nas superfícies irradiadas e opostas à irradiada nos corpos de prova com 1 mm de espessura

The effect of fluoride therapies on the morphology of bleached human dental enamel.

The aim of this in vitro study was to evaluate qualitatively the surface morphology of enamel bleached with 35% hydrogen peroxide (HP) followed by application of fluoridated agents. Forty intact pre molars were randomly distributed into four groups (n = 10), treated as follows: Group I (control group) remained stored in artificial saliva at 37 °C, Group II - 35% HP; Group III - 35% HP + acidulated fluoride (1.23%) and Group IV - 35% HP + neutral fluoride (2%). The experimental groups received three applications of bleaching gel and after the last application all specimens were polished. This procedure was repeated after 7 and 14 days, and during the intervals of applications, the specimens were stored in artificial saliva at 37°C. Scanning electron microscopy (SEM) analysis showed superficial irregularities and porosities to varying degrees in bleached enamel compared to control group. Sample evaluation was made by attributing scores, and data were statistically analyzed using Kruskal-Wallis and Dunn tests (P < 0.05). SEM qualitative investigation demonstrated that 35% hydrogen peroxide affected human dental enamel morphology, producing porosities, depressions, and superficial irregularities at various degrees. These morphological changes were higher after the application of 1.23% acidulated fluoride gel.

Avaliação de profundidade de polimerização de duas resinas compostas, utilizando dois tipos de fotoativadores, sendo um de luz halógena e outro LED / Evaluation of polymerization depth of two current composite resins, using two types of light sources - halogen light and LED

Este estudo avaliou a profundidade de polimerização de duas resinas compostas - Z350 (3M) e Venus (Heraeus Kulzer) por meio de teste de microdureza Vickers. As resinas foram inseridas em porção única, em matriz de polipropileno preta, com espessuras de 1, 2, 3 e 4 mm, e fotoativadas com luz halógena e LED por 20 segundos. Foram obtidos 500 valores de dureza referentes aos 2 materiais, 2 fontes de ativação, 5 espessuras, 5 repetições e 5 medidas em cada corpo de prova, cuja média resultou em 100 valores para análise estatística. Foram utilizados os testes de análise de variância e Tukey. Os resultados mostraram que a resina Venus não apresentou diferença estatisticamente significante com 1 mm de espessura em relação à superfície irradiada (0 mm) com luz halógena e com LED; porém, a partir de 2 mm de espessura, a dureza foi sempre menor que a superfície irradiada. A resina Z350 (além de apresentar valores de dureza sempre superiores aos da resina Venus) quando fotoativada com o LED não apresentou diferença estatística em relação à superfície irradiada até 2 mm (p < 0,05). Concluiu-se que as resinas Z350 e Venus apresentaram valores diferentes; porém, em profundidade de polimerização, seus comportamentos foram semelhantes quando foi utilizada a luz halógena, polimerizando adequadamente espessuras de até 2 mm

Argon ion laser curing depth effect on a composite resin.

The aim of this study was to define optimal power settings as well as curing time associated with evaluating the curing depth of a composite resin as a function of Vickers hardness. The tests were performed with a hybrid composite resin cured with a halogen lamp and argon ion laser, with different exposure times and power settings. The composite resin bulk technique was used using a black polypropylene matrix with thicknesses ranging from 1 to 4 mm and Vickers microhardness was measured on the opposite surface of the light activation. ANOVA and Tukey statistical tests were used. The results showed that the groups activated by the laser for 20 s, at 200 and 250 mW, did not present statistically significant differences regarding the halogen lamp with 1 mm thickness, but the halogen lamp showed better results with thickness values more than 2 mm (p < 0.05).

Influence of aluminum oxide sandblasting associated with Nd:YAG or Er:YAG lasers on shear bond strength of a feldspathic ceramic to resin cements.

OBJECTIVE: This in vitro study evaluated the influence of the surface pretreatment of a feldspathic ceramic on the shear bond strength of two different resin cements. BACKGROUND DATA: Although several conventional surface treatments have been used on feldspathic ceramic, few studies have investigated the effects of an alternative surface treatment, the association of aluminum oxide sandblasting with Nd:YAG and Er: YAG lasers. METHODS: Sixty samples made of a feldspathic ceramic were divided into three groups (n = 20) and treated with (1) controlled-air abrasion with Al(2)O(3) + 10% hydrofluoric acid (HF), (2) Al(2)O(3) + Er:YAG laser, and (3) Al(2)O(3) +Nd:YAG laser. Afterward, silane (Dentsply) was applied on each treated surface. Each of the three main groups was divided into two subgroups (n = 10), where a different resin cement was employed for each subgroup. It was built a cylinder with resin cement (RelyX Arc) in subgroup (A) and with self-adhesive cement (RelyX U100) in subgroup (B). After 24 h at 37 degrees C, the prepared specimens were submitted to shear bond strength test and stereoscopic evaluation to determine the type of failure. RESULTS: Bond strength mean values were not statistically significant for the surface treatment methods or resin cements. CONCLUSION: The null surface treatment proposed with aluminum oxide sandblasting associated with the Er:YAG or Nd:YAG laser and using cementation with self-adhesive cement can be an alternative bonding technique for feldspathic ceramic, since it was as effective as the conventional treatment with aluminum oxide sandblasting and hydrofluoric acid using the conventional resin cement.

Argon ion laser and halogen lamp activation of a dark and light resin composite: microhardness after long-term storage.

UNLABELLED: The objective of this study was to evaluate in vitro light activation of the nano-filled resin composite Vita shade A1 and A3 with a halogen lamp (QTH) and argon ion laser by Knoop microhardness profile. MATERIALS AND METHODS: Specimens of nanofilled composite resin (Z350-3 M-ESPE) Vita shade A1 and A3 were prepared with a single increment inserted in 2.0-mm-thick and 3-mm diameter disc-shaped Teflon mold. The light activation was performed with QTH for 20 s (with an intensity of approximately 1,000 mW/cm(2) and 700 mW/cm(2)) and argon ion laser for 10 s (with a power of 150 mW and 200 mW). Knoop microhardness test was performed after 24 h and 6 months. The specimens were divided into the 16 experimental groups (n = 10), according to the factors under study: photoactivation form, resin shade, and storage time. Knoop microhardness data was analyzed by a factorial ANOVA and Tukey s tests at the 0.05 level of significance. RESULTS: Argon ion laser was not able to photo-activate the darker shade of the nanofilled resin composite evaluated but when used with 200 mW it can be as effective as QTH to photo-activate the lighter shade with only 50% of the time exposure. After 6 months storage, an increase in the means of Knoop microhardness values were observed. CONCLUSIONS: Light-activation significantly influenced the Knoop microhardness values for the darker nanofilled resin composite.