NATHALIA ZANINI ALVES STEPHANO

NATHALIA ZANINI ALVES STEPHANO

Página do item completo

Resultados de Busca

Agora exibindo 1 - 10 de 17

Caries preventive action of Nd:YAG and fluoride in three different pH conditions
2023 - JUVINO, AMANDA C.; ZANINI, NATHALIA A.; AVELINO, SABRINA G.; OLIVEIRA, YASMIN R.F. de; GERMANO, GLEICE C.M.; EDUARDO, CARLOS de P.; ZEZELL, DENISE M.
This in vitro study aimed to evaluate the preventive action of topical fluoride application combined with laser irradiation under different pH conditions using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning ElectronMicroscopy (SEM). A total of 180 samples of human dental enamel were prepared and divided into groups: Negative Control, Fluoride (FFA 12.300 F􀀀/g), Laser (Nd:YAG 84.9 J/cm2), and Laser + Fluoride (Nd:YAG 84.9 J/cm2 + FFA 12.300 F􀀀/g). The pH cycling was performed at three different pH conditions: pH 5 (below the critical pH for hydroxyapatite), pH 4.5 (below the critical pH in the presence of fluorapatite), and pH 4 (investigating acid resistance of hydroxyapatite and fluorapatite forms with laser irradiation). In the FTIR analysis, the Laser + Fluoride group demonstrated statistically significant differences compared to the Negative Control group and Fluoride group at pH 4.5 and pH 4 when evaluating the phosphate bands. Similar results were observed in the SEM analysis, where the Laser + Fluoride group exhibited lower demineralization compared to the other treatments at pH 4.5 and pH 4. In conclusion, the Laser + Fluoride group demonstrated a significant reduction in demineralization even at pH levels below the critical threshold for fluorapatite, highlighting its superior acid resistance compared to fluoride alone.
Erbium laser in the debonding of ceramics
2022 - ZANINI, NATHALIA A.; CARAMEL-JUVINO, AMANDA; ANA, PATRICIA A.; ZEZELL, DENISE M.
Background: The debonding of crowns and ceramic veneers with laser is already a reality in the clinic. It presents benefits in comparison to traditional removal with the use of a rotating instrument; however, there is still no consolidated protocol and many professionals use it without the necessary scientific basis. Objective: The aim of this work was to perform a literature review on the debonding of indirect ceramic restorations using the Er:YAG and Er,Cr:YSGG lasers to provide clinical professionals and the scientific community a careful analysis, and also to guiding the use of irradiation at laser for such procedures. Methods: Bibliographic searches were performed in the following databases: Pubmed, Web of Science and Google Scholar. According to the inclusion criteria adopted, twenty-seven clinical and in vitro studies were selected in the period from 2007 to 2021. In the present work, the composition of the crowns and facets, as well as the types of cement and the laser irradiation protocols adopted in the selected studies is detailed. Conclusions: It was concluded that the use of erbium lasers for debonding of indirect ceramic restorations proved to be more selective and conservative when compared to removal with a rotary diamond instrument. Furthermore, it was shown to be in more efficient in debonding different types of ceramics. However, there are great variations in the “debonding” protocols, which emphasizes the need for further studies that seek to standardize the irradiation protocols considering the different clinical situations.
Evaluation of the anti-caries effect beyond the critical enamel pH of preventive treatment of fluoride associated with Nd:YAG laser irradiation
2021 - JUVINO, AMANDA C.; ROMANO, MARIANA; ALVES, NATHALIA Z.; FREITAS, THAIS R.; ZAMATARO, CLAUDIA B.; ZEZELL, DENISE M.
This study aimed to evaluate the anti-caries effect of fluoride associated with Nd:YAG laser irradiation in the h-eatment of enamel Eight groups (n = S) were analyzed: Negative Control pH 4.5; Negative control pH 4; Fluoride pH 4.5; Fluoride pH 4; Nd-YAG pH 4.5; Nd-YAG pH 4; (Fluoride + Nd-YAG) pH 4.5 and (Fluoride + Nd-YAG) pH 4. All samples were analyzed by Scanning Electron Microscopy (SEM) before and after the cycle. Quantification of phosphorus in the cycling solutions was carried out using the colorimetric method, as an indication of enamel demineralization. The anti-caries effect of the Fluoride + Nd: YAG treatment in addition to the critical pH of the enamel can be observed in the morphological analysis, however in the analysis of the demineralization solutions, the amount of phosphorus showed a difference only in the Fluoiide group compared to the others in the investigative pH.
Estudo in vitro para determinação de protocolo de irradiação para remoção de facetas cerâmicas em esmalte dental com laser de Er,Cr:YSGG
2021 - ALVES, NATHALIA Z.
A reabilitação estética por meio de facetas cerâmicas tornou-se prática frequente nas clínicas odontológicas. Contudo sua substituição, por diversos motivos, pode-se fazer necessária O uso do laser pode facilitar essa remoção quando necessária. Este trabalho tem como objetivo elaborar um protocolo para remover facetas cerâmicas sem causar danos à estrutura pulpar através da avaliação da irradiação com laser de Er,Cr:YSGG pulsado, bem como analisar se estes parâmetros causam alguma alteração morfológica, química ou óptica nos prismas de esmalte e se o aumento de temperatura ultrapassa 5,5 °C e 11 °C, valores esses que poderiam gerar danos a polpa e aos ligamentos periodontais, respectivamente. Na primeira parte do experimento foram preparados 180 fragmentos de dentes humanos que foram distribuídas aleatoriamente em 12 grupos experimentais (N=15), sendo 6 grupos irradiados e 6 grupos controle. Para a colagem das facetas cerâmicas de dissilicato de lítio com 0,7 mm utilizamos três diferentes cimentos resinosos (Variolink Veneer, RelyX U200 e RelyX Veneer). O cimento Rely X U200 não é um cimento resinoso preconizado pelo fabricante para s cimentação de facetas, mas mesmo assim o utilizamos, para remover quaisquer dúvidas relacionadas à alteração morfológica ocorrida no esmalte devido ao condicionamento ácido. O laser de Er,Cr:YSGG (2,78 μm) foi usado em dois protocolos de irradiação: 3,5 W; 48,14 J/cm2; 20 Hz, sem contato e 3,0 W de potência média; 40J/cm2 de densidade de energia e taxa de repetição de 20 Hz, sem contato e após a irradiação realizamos cisalhamento em todas as amostras. As análises morfológicas, ópticas e elementares do esmalte foram realizadas antes da cimentação e após a remoção, utilizando microscopia eletrônica de varredura (MEV), tomografia de coerência óptica (OCT) e espectroscopia de fluorescência de raios X de energia dispersiva (EDS). Na segunda parte do experimento foram utilizados 60 dentes humanos (incisivos inferiores) e estes foram distribuídos aleatoriamente em 12 grupos experimentais (N=5), sendo 6 grupos irradiados a laser e 6 grupos controle (remoção com instrumento rotatório diamantado), nos quais realizamos a análise de temperatura durante a remoção das facetas por ambos os métodos. O nível de significância estatística adotado foi de 5%. As medidas por EDS, após a remoção das facetas, revelaram um aumento significativo na quantidade de silício e carbono, bem como uma diminuição no conteúdo de cálcio e fosfato. A análise morfológica mostrou alteração dos prismas do esmalte nos grupos no quais foram utilizados os cimentos RelyX Veneer e Variolink Veneer, sendo esta alteração não decorrente da irradiação com laser. Apesar de não observamos alterações morfológicas nos prismas de esmalte, ocorreu aumento no coeficiente de atenuação óptica em dois grupos. Para avaliar o tipo de fratura que ocorreu no momento do cisalhamento, utilizamos as imagens geradas pelo MEV em um aumento de 50X e realizamos um teste de concordância intra-avaliador, Kappa = 0,951, e observamos que nos grupos com irradiação a laser de 3W as fraturas foram predominantemente do tipo adesiva. Nos grupos com irradiação a laser de 3,5W as fraturas foram predominantemente do tipo coesiva e nos grupos controles observamos uma variação entre os 3 padrões de fratura variando confirme o tipo de cimento resinoso, sendo que nos grupos CRU3 e CRU3,5 nenhuma fratura coesiva ocorreu. A análise de temperatura constatou que o uso de instrumento rotatório diamantado apresentou valores estatisticamente maiores quando comparados com a remoção a laser. Conclui-se que o laser de Er,Cr:YSGG é eficaz para remover laminados de dissilicato de lítio sem causar danos aos prismas de esmalte.
Analysis of ceramic laminates removal with Er,Cr:YSGG laser by optical coherence tomography
2019 - ZANINI, NATHALIA; ZAMATARO, CLAUDIA B.; RABELO, THAIS F.; JUVINO, AMANDA C.; KUCHAR, NIELSEN G.; CASTRO, PEDRO; ANA, PATRICIA da; ZEZELL, DENISE
Porcelain laminated veneers have been widely used. For wear of hard tissue such as enamel and dentin, the diamond rotary instrument is the most traditional, but the laser has become recently used to remove aesthetic facets. Optical coherence tomography (OCT) used as an optical biopsy, is important for morphological analysis and attenuation coefficient is related to the property of the photons to be scattered by the samples. After approval by the Ethics Committee, the present study investigated the detachment of 30 ceramic E-max fragments cemented in human dental enamel of dimensions 3mm x 3mm x 0.7mm with 3 types of resin cements, RelxY Veneer, Relx U200 and Variolink Veneer. The samples (Enamel + Ceramic Fragment) were randomly distributed in the 3 groups and cemented according to the manufacturer. After that, they were prepared for irradiation with the Er,Cr: YSSG laser under predetermined conditions (3.5 and 3W, 20Hz, 60% water and 40% air flow). OCT analysis was done before and after irradiation. We observed that themorphological changes of the enamel surface showed an increased surface area due to the cement remaining in the enamel.We concluded that the Er, Cr: YSGG laser, when used in the irradiation protocol tested, seems to be a safe tool for the removal of laminates.
Removal of laminates with Er,Cr:YSGG laser from dental enamel submitted to gamma radiation
2019 - RABELO, THAIS F.; ZAMATARO, CLAUDIA B.; ZANINI, NATHALIA; JUVINO, AMANDA C.; KUCHAR, NIELSEN G.; CASTRO, PEDRO A.A.; ZEZELL, DENISE M.
Background: Modern Dentistry is characterized by the search for aesthetic perfection in the smile. Many efforts are made regarding procedures related to manufacturing, cementing, maintenance and removal of ceramic laminates. The laser removal of laminates has become more frequent when the aesthetical procedures needs to be replaced. On the other hand, the head and neck cancer treatment causes comorbidities in the buccal environment when laminates are in place. Objective: To evaluate in vitro the removal of ceramic fragments by means of Er,Cr:YSGG laser irradiation, after gamma radiation. Methods: 20 Lithium disilicate veneers were cemented with Variolink to human dental enamel and then samples were irradiated with 0.07 kGy. After gamma irradiation, the laminates removal with Er,Cr:YSGG laser was performed. The control group was not subjected to gamma radiation. Dental enamel samples were analyzed by Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FTIR) and Surface Microhardness Loss (SMH). Results: SEM has shown that less cement was found after removal of the facets in gamma irradiated group when compared to the control. For both groups there was alteration of the SMH possibly due to the use of the adhesive system. When performed intra group analysis, the sample being its own control of baseline in the FTIR analysis, there were no band shifts or formation of new compounds on the surface of human dental enamel. Conclusions: The Er,Cr:YSGG laser is an effective alternative for laminates removal in human dental enamel even when it is subjected to gamma radiation.
Calcium analysis of gamma sterilized human dentin submmited to Er,Cr:YSGG laser irradiation
2019 - KUCHAR, NIELSEN G.; ZAMATARO, CLAUDIA B.; RABELO, THAIS; JUVINO, AMANDA; ZANINI, NATHALIA; CASTRO, PEDRO; ZEZELL, DENISE M.
Studies report that gamma radiation changes the oral cavity of patients submitted to radiotherapy. These changes include xerostomia, resulting in an unsaturation of calciumand phosphate in the oral cavity. However, human enamel samples isolated from the altered oral environmentwhen irradiatedwithgamma radiation at doses of up to 25kGy (much higher than radiotherapy doses) were shown to have undergone no changes in molecular hardness or micro surface. After approval of the Research Ethics Committee, 20 human dentin samples were evaluated before and after irradiation, split randomly into control group (n = 10) and irradiated group (n = 10) treated with 25.0 kGy at the Co60 multipurpose irradiator and irradiated with Er,Cr:YSGG laser in the parameters: 8.5 J/cm2 in the Fourier Transform Infrared Spectroscopy (FTIR), % surface Microhardness loss and Scanning Electron Microscopy (SEM). At the end, acidic biopsies were performed to quantify the concentration of calcium present in the samples. In the results of FTIR analysis differences were found only in the bands of organic content and in the inorganic content, difference were not found between before and after irradiations. The EDS and % Surface Microhardness loss analysis corroborates these findings, as well as no significant loss of the Calcium content before and after their radiation with Co60 at 25 kGy and with the Er,Cr:YSGG laser. These findings lead us to a new hypothesis of behavior of the hydroxyapatite crystal submitted to the gamma irradiation.
Er,Cr:YSGG laser irradiation associated to fluoride for in situ model using gamma sterilized dentin and enamel
2019 - ZAMATARO, CLAUDIA B.; RABELO, THAIS F.; ZANINI, NATHALIA; JUVINO, AMANDA C.; KUCHAR, NIELSEN G.; CASTRO, PEDRO A.L.; ANA, PATRICIA A. da; ZEZELL, DENISE M.
The in situ intraoral model uses human dental enamel samples (HDE) in order to analyse the de-remineralization processes using the buccal environment without interfering into the patients’ natural dentition. The main ethical concern from this model is the biosafety. Gamma radiation is a very efficient sterilization method that is not expected to alter the mineral content of the hard tissues, avoiding biases in the results. Thus 40 HDE samples were irradiated through a source of 60Co multipurpose irradiator aiming complete sterilization (25 KGy/h) with the purpose of accumulating the native plaque on them at an in situ study. An Er,Cr:YSGG laser was used alone and in combination with the topical applications of: 1-dentifrice (1,100 lg F-/g) or 2-APF (12,300 lg F-/g). Morphological analyses were performed by scanning electron microscopy (SEM), determination of alkali-soluble fluoride concentration by specific ion electrode and microhardness determination. Then, the 15 volunteers used palatal devices containing previously treated HDE samples and remained using F dentifrice. The FTIR findings established that gamma radiation could be used aiming HDE sterilization. The Knoop hardness number was within the range of that of natural dentin of human origin. X-ray fluorescence shows that irradiated dentin has great similarity with natural dentin from the point of view of chemical composition. SEM analyses showed that there was no thermal damage or interprismatic morphological changes in the hydroxyapatite structure of human dental dentin outside the buccal environment when using doses of gamma irradiation up to 25 kGy.
In vitro determination of the critical pH demineralization of human dental enamel irradiated with Nd:YAG laser associated with fluoridated product
2019 - JUVINO, AMANDA C.; ZAMATARO, CLAUDIA B.; RABELO, THAIS F.; KUCHAR, NIELSEN G.; ZANINI, NATHALIA; CASTRO, PEDRO; ZEZELL, DENISE
The use of fluoride products associated with high intensity laser irradiation are beneficial for dental caries prevention because it increases the surface area, improving the formation of fluorapatite (FA), which gives greater acid-resistance of enamel against bacterial acids. The objective of this study is to determine the critical pH of dental enamel treated with acid fluoride phosphate 12,300 lF-/g (APF) and Nd:YAG laser 84 J/cm2, as there is no precedent to determine this pH. The study consisted of 4 groups (n = 15): G1: Negative Control; G2: APF; G3: Nd:YAG; G4: APF + Nd:YAG. Each group was randomized into three subgroups (n = 5) for pH cycling. The cycling was designed to simulate three conditions: below critical pH of enamel hydroxyapatite (pH 5.0); pH below critical for hydroxyapatite and fluorapatite (pH 4.5); condition further below the critical situation to investigate extent of acid resistance of the enamel (pH 4.0). The samples were analyzed by scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR) and solutions were quantified fluoride (specific ion electrode) and phosphate (colorimetric method). In SEM and FTIR (phosphate band) at pH 5, only the APF and APF + Nd:YAG groups did not present demineralization. At pH 4.5, only the APF + Nd:YAG group was integrated. At pH 4, APF + Nd:YAG showed signs of mild demineralization while the other groups showed aggressive signals. It is concluded that the irradiated fluorapatite has critical dissolution pH different from fluorapatite formed only with the application of fluorine.
Morphological, optical, and elemental analysis of dental enamel after debonding laminate veneer with Er,Cr:YSGG laser
2021 - ZANINI, NATHALIA A.; RABELO, THAIS F.; ZAMATARO, CLAUDIA B.; CARAMEL-JUVINO, AMANDA; ANA, PATRICIA A.; ZEZELL, DENISE M.
Laminate veneer removal is becoming a routine procedure at the dental clinic and the use of laser can facilitate its removal. This work aimed to evaluate the morphological, elemental, and optical changes in the remaining enamel after veneer removal using Er,Cr:YSGG laser. Forty‐four enamel slabs were prepared and randomly distributed into nine experimental groups, for bonding using lithium disilicate laminates with three different luting agents (Variolink Veneer, RelyX U200, and RelyX Veneer). Then each agent was debonded using Er,Cr:YSGG laser (2.78 μm) using two different protocols:3.5 W, 48.14 J/cm2, 20 Hz non‐contact and 3.0 W, 48.14 J/cm2, 20 Hz non‐contact. The morphological, optical, and elemental analysis of enamel was performed before cementation and after laser debonding, using scanning electron microscopy (SEM), optical coherence tomography (OCT), and energy‐dispersive X‐ray spectroscopy (EDS). The level of statistical significance adopted was 5%. The EDS analysis of enamel after debonding revealed a significant increase in silane and carbon, as well as a decrease in calcium and phosphate contents. Analysis showed the presence of residual cement in most experimental groups but the morphological analysis showed alteration of the enamel's prisms only in the groups that used RelyX Veneer and Variolink Veneer cements. There was no evidence of deleterious morphological changes resulting from irradiation. However, an increase in the optical attenuation coefficient by the OCT was observed due to the presence of the remaining cement. It can be concluded that the Er,Cr:YSGG laser, in the mean powers used, is efficient for veneer removal without causing deleterious effects for the enamel.