Effect of low temperature and room temperature on the depth of cure of bulk-fill composite resins

The study analyzed the influence of temperature on the depth of cure of bulk-fill composite resins. Three discs (ISO 4049/2000) from each group were made, and four restorative materials were investigated: Opus Bulk-Fill Flow, Opus Bulk-Fill APS, Filtek™ One Bulk-Fill, and Filtek™ Bulk-Fill Flow. They were light-cured (Gnatus ± 1,200 mW/cm2) for 20 seconds, varying the temperature (23°C and 5°C) and simulating the use of the product both at room temperature and under refrigeration. The materials were inserted in aluminum matrices with 10 mm in depth and 4 mm in diameter. A clear film strip and a glass microscope slide were positioned at the top and bottom surfaces. The material was condensed and light-cured with the tip of the light source in close contact, for 20 seconds on the top surface. Immediately after irradiation, the samples were removed from the mold, and the uncured part was removed with a plastic spatula. The measurement was performed with a micrometer ± 0.1 mm, and the value was divided by 2. The data were analyzed with two-way ANOVA at a significance of 0.05. There was a statistical difference in the temperature between the results obtained in Opus Bulk-Fill APS (p <0.001) and Filtek™ Bulk-Fill Flow (p = 0.018) resins. For the temperature of 5°C, Filtek™ Bulk-Fill Flow showed a statistical difference compared to the other resins, while Opus Bulk-Fill Flow and Opus Bulk-Fill APS did not. For the temperature of 23°C, Filtek™ Bulk-Fill Flow maintained the statistical difference from the others, but Filtek™ One Bulk-Fill and Opus Bulk-Fill APS did not present statistical differences. Storing the Filtek™ Bulk-Fill Flow composite resin in the refrigerator caused a greater depth of cure than the other resins, and the depth of cure decreased at room temperature. As for Opus Bulk-Fill APS, the depth of cure decreased proportionally to the temperature decrease. The temperature may affect the depth of cure of some composite resins.

Ozone disinfection for viruses with applications in healthcare environments: a scoping review

Abstract The aim of this scoping review was to provide sufficient information about the effectiveness of ozone gas in virus inactivation of surfaces and objects under different environmental conditions. The review was performed according to the list of PRISMA SrC recommendations and the JBI Manual for Evidence Synthesis for Scoping Reviews. The review was registered in Open Science Framework (OSF). EMBASE (Ovid), Lilacs, LIVIVO, MEDLINE (PubMed), SciELO, Scopus and Web of Science were primary sources, and "gray literature" was searched in OpenGray and OpenThesis. A study was included if it reported primary data on the effect of ozone gas application for vehicle-borne and airborne virus inactivation. No language or publication date restriction was applied. The search was conduct on July 1, 2020. A total of 16,120 studies were screened, and after exclusion of noneligible studies, fifteen studies fulfilled all selection criteria. Application of ozone gas varied in terms of concentration, ozone exposure period and the devices used to generate ozone gas. Twelve studies showed positive results for inactivation of different virus types, including bacteriophages, SARS-CoV-2 surrogates and other vehicle-borne viruses. Most of the studies were classified as unclear regarding sponsorship status. Although most of the population has not yet been vaccinated against COVID-19, disinfection of environments, surfaces, and objects is an essential prevention strategy to control the spread of this disease. The results of this Scoping Review demonstrate that ozone gas is promising for viral disinfection of surfaces.

Can ozone or violet light improve the color change or physicochemical properties of hydrogen peroxide-bleached tooth?

Abstract: This study investigated the bleaching effectiveness and the physicochemical effects on enamel of violet light and ozone, associate or not to hydrogen peroxide, compared to 35%-hydrogen peroxide. Enamel-dentin blocks from human molars were randomly allocated to receive one of the following bleaching protocols (n=15): (HP) 35%-hydrogen peroxide, (VL) violet light, (OZ) ozone, the association between hydrogen peroxide with ozone (OZ+HP) or violet light (VL+HP). All protocols were performed in two sessions with a 48h interval. Color (spectrophotometer) and mineral composition (Raman spectroscopy) were measured before and after the bleaching. Color changes were calculated by ΔEab, ΔE00, and whitening index (WI). The surface roughness was measured with an atomic force microscope. Data were analyzed by One-way or Two-way repeated measure ANOVA followed by the Tukey's test (α = 0.05). The lowest color change values (either measured by WI, ΔEab, or ΔE00) were observed for VL and OZ used with no HP. Violet light associate with HP was unable to improve the color changes observed for the peroxide alone, in combination with OZ and HP, the highest color changes were verified. Regardless of bleaching protocol, the bleached enamel presented higher contents of PO4 and CO3 -2 than those observed at baseline. All bleaching protocols resulted in similar enamel surface roughness. Both the VL and the OZ caused reduced effects on the enamel color change when used alone. The ozone therapy improved the bleaching effect in the group that received the association of HP.

Resumo O objetivo deste estudo foi avaliar o efeito clareador e físico-químico no esmalte de luz violeta e ozônio, associado ou não ao peróxido de hidrogênio, comparado a 35% de peróxido de hidrogênio. Blocos de esmalte-dentina de molares humanos foram alocados aleatoriamente para receber um dos seguintes protocolos de clareamento (n = 15): (HP) peróxido de hidrogênio a 35%, (VL) luz violeta, (OZ) ozônio, a associação entre peróxido de hidrogênio com ozônio (HP+OZ) ou luz violeta (HP+VL). Todos os protocolos foram realizados em duas sessões, com intervalo de 48 horas entre eles. A cor (espectrofotômetro) e a composição mineral (espectroscopia Raman) do dente foram medidas antes e após os procedimentos de clareamento. As alterações de cor foram calculadas por ΔEab e ΔE00, e o índice de brancura foram calculados. A rugosidade da superfície das amostras clareadas foi medida por microscópio de força atômica. Os dados foram analisados por ANOVA One way ou ANOVA two way de medidas repetidas seguida pelo teste de Tukey (α = 0,05). Os menores valores de alterações de cor (medidos por WI, ΔEab ou ΔE00) foram observados para VL e OZ usados na ausência de HP. VL associada ao HP não foi capaz de melhorar as alterações de cor observadas com o uso do HP, mas a combinação de OZ e HP produz as maiores alterações de cor. Independentemente do protocolo de clareamento, o esmalte clareado apresentou maiores teores de PO4 e CO3 -2 do que os observados inicialmente. Não foi observada diferença significativa entre os protocolos de clareamento testados em relação à rugosidade da superfície do esmalte. É possível concluir que a VL ou o OZ tiveram efeitos reduzidos na mudança de cor do esmalte quando usados sozinhos. A terapia com OZ melhorou o efeito clareador do HP.

Lesão cervical não cariosa e hipersensibilidade dentinária: relato de caso clínico / Non-carious cervical lesions and dental hypersensitivity: a clinical case reportq

As lesões cervicais não cariosas (LCNC) caracterizam-se pela perda irreversível e gradual de tecido mineralizado junto da junção amelo-cementária, sem qualquer envolvimento bacteriano e é um dos fatores relacionados à hipersensibilidade dentinária (HD), caracterizado por uma dor aguda, provocada e de curta duração. Paciente L.C.M, sexo feminino, 38 anos de idade, compareceu à Clínica Odontológica da Faculdade Patos de Minas (FPM), relatando sensibilidade nos dentes 44 e 45. Após assinado o Termo de consentimento livre e esclarecido (TCLE), a paciente realizou tomadas radiográficas e foi submetida a anamnese e exame clínico, no qual, foi observada a presença de LCNC e diagnosticada como multifatorial. O ajuste oclusal foi realizado com pontas diamantadas e borrachas abrasivas removendo contatos prematuros. A restauração direta em resina composta foi indicada para a obliteração mecânica/física dos túbulos dentinários, como opção de tratamento. Foi realizado condicionamento ácido do esmalte, por 30seg e da dentina por 15seg, com ácido fosfórico 37% (Condac, FGM), lavado com água pelo mesmo tempo, seguido de controle de umidade e duas camadas de adesivo convencional (Ambar, FGM), fotoativando apenas a segunda camada por 20seg com LED (Kavo 1100 mW/cm²). A LCNC foi restaurada com resina composta convencional (A3E, Llis, FGM), com dois incrementos de aproximadamente 2mm cada, seguidas de acabamento e polimento. A hipersensibilidade foi cessada imediatamente logo após o ajuste oclusal e tratamento restaurador, ressaltando a importância do diagnóstico e do exame clínico. A remoção dos contatos prematuros e a restauração com resina composta foram essenciais para o sucesso deste tratamento, visto que a origem da perda mineral foi cessada concomitante com o alívio da dor.

The non-carious cervical lesions (NCCI) are characterized by the irreversible and gradual loss of mineralized tissue combined to the amelo-cementary junction, without any bacteria participation and is one of the factors related to dentin hypersensitivity (HD), classified by an acute pain, incited and in short term. Patient L.C.M, woman, 38 years old, attended to the Dental Clinic of Faculty Patos de Minas (FPM), reporting sensitivity on teeth 44 and 45. After signed the agreement form, the patient was submitted to an anamnesis, clinical exam and x-ray, in which, it was detected the presence of NCCL, diagnosed by multifactorial. Occlusal adjustment was performed with diamond and rubber tips removing the early contact area. The resin-composite restoration was recommended as a treatment option to physic and mechanically obliterate the dentin tubules. Enamel was etched for 30 sec and dentin for 15 sec with 37% phosphoric acid (Condac, FGM) and washed with water for 30 sec. Two layers of a dentin adhesive (Ambar, FGM) was applied and light cured for 20 sec with a LED light curing unit (Kavo 1100 mW / cm²). The NCCL was restored with a resin-composite (A3E, Llis, FGM), with two increments of approximately 2mm each, followed by a finishing and polishing protocol. The hypersensitivity was interrupted immediately after occlusal adjustment and restorative treatment, emphasizing the importance of diagnosis and clinical exam. Removal of premature contacts and restoration with composite resin were essential for the success of this treatment, since the origin of the mineral loss was controlled concomitantly with pain relief.