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Document type: Trabalho de Conclusão de Curso
Access type: Acesso Embargado
Title: Effect of method used for sample preparation and light curing design on hardness and degree of conversion on bulk fill composite resin in molar teeth
Alternate title (s): Efeito do modo de preparo de amostras e do design de fontes fotopolimerizadoras em dureza knoop e grau de conversão em resinas bulk fill em dentes molares
Author: Schettini, Ana Cecília Teodoro
First Advisor: Soares, Carlos José
First coorientator: Braga, Stella Sueli Lourenço
First member of the Committee: Moura, Camilla Christian Gomes
Second member of the Committee: Soares, Priscilla Barbosa Ferreira
Third member of the Committee: Barcelos, Luciana Mendes
Summary: OBJECTIVES: The aim of this study was to evaluate the effect of the sample preparation of bulk fill resin composites in molar influenced by the light curing units (LCUs) on Knoop hardness (KHN, N/mm2) and degree of conversion (DC, %) in different depths and regions. METHODS: Two molar teeth were selected. One molar was embedded in polystyrene resin, sectioned in three parts and received a MOD preparation with lateral cavities surfaces pre-polished and the other one was embedded and the MOD cavity was performed. Standardized expulsive cavity with 4 mm depth in the occlusal area and 5 mm at the proximal were made. Patient simulator with 44 mm of mouth opening had the molar teeth positioned as a second mandibular molar. Restorations were performed using a high viscosity bulk fill resin composite (Opus Bulk Fill, FGM) and light cured using two LCUs: VALO Cordless (Ultradent) and Bluephase G2 (Ivoclar-Vivadent). The resin composite was placed in one increment and light-cured for 40 s on distal and mesial occlusal surfaces. Samples were prepared: CEmPol, performed conventionally, embedded in polystyrene resin and polished before testing; CPol; performed conventionally, without embedment in polystyrene resin but polished before testing; PrePol, performed in a pre-polished molar cavity with no embedment or polishing before testing. KHN was calculated in different depths in two regions of mesial, occlusal and distal cavities. The degree of conversion was measured by Raman spectroscopy at the top and bottom of mesial, distal and at occlusal regions. Data of KHN and DC were analyzed by using 2-way repeated measurement followed by Tukey test (α = 0.05). RESULTS: Sample preparation method (P < 0.001), depth of restoration (P < 0.001) and the interaction between sample method and depth of restoration (P = 0.003) influence the KHN values. Significant influence was detected for sample confection method (P < 0.001), tooth region (P < 0.001), and for interaction between sample confection method and tooth region (P = 0.002) for DC values. In general, KHN reduced significantly from the top to the bottom of the restoration, mainly at proximal boxes. The PrePol method was the more efficient method to detect the significant difference for depth of the restoration and tooth region. Lower DC was found on the gingival region on the proximal box on the restoration, irrespective of the location being mesial, occlusal or distal area. CONCLUSION: The sample preparation that was embedded and polished had the uncompleted polymerized monomers layer removed due to the polishing process reducing the capacity of detection of KHN and DC values of bulk fill composite restorations influenced by depth or region of the cavities. The use of PrePol method was able to detect difference produced by light activation in deeper areas.
Keywords: Bulk fill composite
Knoop hardness
Degree of conversion
Light curing design
Language: eng
Country: Brasil
Publisher: Universidade Federal de Uberlândia
Quote: SCHETTINI, Ana Cecília Teodoro. Effect of method used for sample preparation and light curing design on hardness and degree of conversion on bulk fill composite resin in molar teeth. 2019. 25 f. Trabalho de Conclusão de Curso (Graduação em Odontologia) – Universidade Federal de Uberlândia, Uberlândia, 2019.
Date of defense: 22-Jun-2019
Appears in Collections:TCC - Odontologia

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