Influence of light curing units and fluoride mouthrinse on morphological surface and color stability of a nanofilled composite resin

Composite resin is a dental material susceptible to color change over time which limits the longevity of restorations made with this material. The influence of light curing units and different fluoride mouthrinses on superficial morphology and color stability of a nanofilled composite resin was evaluated. Specimens (N = 150) were prepared and polished. The experimental groups were divided according to the type of light source (halogen and LED) and immersion media (artificial saliva, 0.05% sodium fluoride solution-manipulated, Fluordent Reach, Oral B, Fluorgard). Specimens remained in artificial saliva for 24-h baseline. For 60 days, they were immersed in solutions for 1 min. Color readout was taken at baseline and after 60 days of immersion. Surface morphology was analyzed by Scanning Electron Microscopy (SEM) after 60 days of immersion. Color change data were submitted to two-way Analysis of Variance and Tukey tests (α = 0.05). Surface morphology was qualitatively analyzed. The factor light source presented no significant variability (P = 0.281), the immersion media, significant variability (P < 0.001) and interaction between factors, no significant variability (P = 0.050). According to SEM observations, no difference was noted in the surface of the specimens polymerized by different light sources, irrespective of the immersion medium. It was concluded that the light source did not influence the color stability of composite, irrespective of the immersion media, and among the fluoride solutions analyzed, Fluorgard was the one that promoted the greatest color change, however, this was not clinically perceptible. The immersion media did not influence the morphology of the studied resin. Microsc. Res. Tech. 77:941–946, 2014. © 2014 Wiley Periodicals, Inc.

Effects of immersion media and repolishing on color stability and superficial morphology of nanofilled composite resin

This study evaluated the influence of fluoride mouth rinses and repolishing on the superficial morphology and color stability of nanofilled resin. About 150 specimens were prepared and polished using aluminum oxide discs for 15 s with a pressure of 2 kg. The experimental groups were divided according to the immersion medium (artificial saliva, 0.5% sodium fluoride, Fluordent Reach, Oral B, Fluorgard) and repolishing procedure (without and with). The specimens were continuously immersed for 1 week. Thereafter, half of each sample was repolished. A color reading was performed after 24 h of immersion in the artificial saliva baseline, after continuous immersion, and after repolishing. The superficial morphology was examined using scanning electron microscopy (SEM) in a qualitative way. Color change (∆E) data were submitted to a mixed analysis of variance using a Shapiro-Wilk test (p>0.05 for the different immersion media) and Sidak's test (p<0.05 for the differences between groups). In the interaction between the repolishing and the immersion media, Fluorgard showed a statistical difference between the ∆E values with and without repolishing (p<0.0001). On the SEM observations, both Fluordent Reach and Fluorgard caused degradation of the superficial resinous matrix of the composite after continuous immersion. This matrix was removed after repolishing.

Deformación del área de corte de las limas endodónticas sometidas a diferentes métodos de precurvatura

Objetive: Evaluate the deformations caused in the cutting edges in the K-file #25 (LK), subjected to pre-beinding of the apcial third using the following methods: finder-bending, cotton-pliers bendin and Flexobend, observed under scanning electron microscopy (SEM). Material and methods: Forty-eight LK#25 were divides into 4 groups (n=12); G1, control; G2, finger-bending; G3, cotton-plier bending, G4, Flexobend. The curvature was standardized in the apical segment of the file at 2 mm of D!. Was constructed a model of acrylic resin that correspond to a canal of 20º of curvature. The files were examined under SEM (260X). Data were analyzed using Fisher´s statistical test with a significance level of 5%. Results: The images showed no alterations in the LK, similar to G3, with no statistical difference. G3 and G4 were statistically different form the other groups (p<0.05). Conclusions: the finger-bending method to curve apical third of LK #25 did not alter the cutting edges, the cotton-pliers bending and Flexobend did alter the cutting edges of the files (AU)

Dentinogenesis imperfecta type II: approach for dental treatment

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of finishing and polishing on color stability of a nanofilled resin immersed in different media

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of the rotary and/or oscillatory reciprocating systems in the morphological changes of narrow and curved molar root canals anatomy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Surface properties and color stability of an acrylic resin combined with an antimicrobial polymer

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Eradication of a Mature Methicillin-Resistant Staphylococcus aureus (MRSA) Biofilm From Acrylic Surfaces

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nanotubos óxidos aplicados a resinas compostas fotoativadas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Liberação controlada de nutrientes e novos sistemas para avaliação de espécies químicas empregadas na fertilização

Pós-graduação em Química - IQ

Fracture resistance of simulated immature teeth after different intra-radicular treatments

The aim of this study was to evaluate the fracture resistance of simulated immature teeth after different intra-radicular treatments. Crowns and roots of bovine incisors were cut transversally and removed to simulate immature teeth. Root canal preparation and flaring were performed using a bur in crown-apex and apex-crown direction. The samples were distributed into 5 groups (n=10): Positive control (PoC) - no root canal flaring or filling; Negative control (NeC) - teeth were sectioned and their root canals were flared; Direct anatomical glass fiber post (RaP) - #2 Reforpost main glass fiber post relined with composite resin; Double tapered conical glass fiber posts (ExP) - #3 Exacto glass fiber post; and #2 Reforpost main glass fiber + Reforpin accessory glass fiber posts (RrP). In RaP, ExP and RrP, 4.0-mm apical plugs were done with MTA Angelus. The specimens were embedded in polystyrene resin inside cylinders and the periodontal ligament was simulated with a polyether-based impression material. The specimens were submitted to compressive fracture strength test (0.5 mm/min at 135° relative to the long axis of the tooth) in a servo-hydraulic mechanical testing machine MTS 810. Data were subjected to one-way ANOVA and Dunnett's C or Tukey's tests (α=0.05). The control groups (PoC and NeC) showed lower fracture strength than the experimental groups. NeC presented the lowest resistance and ExP presented the highest resistance among the experimental groups. The flaring procedures produced a detrimental effect on the fracture resistance of the bovine teeth. Glass fiber intra-radicular posts increased significantly the fracture resistance of simulated immature teeth.

Load-application devices: a comparative strain gauge analysis

In view of the low loading values commonly employed in dentistry, a load-application device (LAD) was developed as option to the universal testing machine (UTM), using strain gauge analysis. The aim of this study was to develop a load-application device (LAD) and compare the LAD with the UTM apparatus under axial and non-axial loads. An external hexagonal implant was inserted into a polyurethane block and one EsthetiCone abutment was connected to the implant. A plastic prosthetic cylinder was screwed onto the abutment and a conical pattern crown was fabricated using acrylic resin. An impression was made and ten identical standard acrylic resin patterns were obtained from the crown impression, which were cast in nickel-chromium alloy (n=10). Four strain gauges were bonded diametrically around the implant. The specimens were subjected to central (C) and lateral (L) axial loads of 30 kgf, on both devices: G1: LAD/C; G2: LAD/L; G3: UTM/C; G4: UTM/L. The data (με) were statistically analyzed by repeated measures ANOVA and Tukey's test (p<0.05). No statistically significant difference was found between the UTM and LAD devices, regardless of the type of load. It was concluded that the LAD is a reliable alternative, which induces microstrains to implants similar to those obtained with the UTM.

Orofacial functions and quality of life in oral health in subjects with dentofacial deformity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Disposição construtiva aplicada em contenção ortodôntica

Disposição construtiva aplicada em contenção ortodôntica. Patente de modelo de utilidade para uma disposição construtiva aplicada em contenção ortodôntica, compreendida por ser do tipo 3x3, com encaixe do tipo "macho-fêmea", sendo que na base da "fêmea" (1) são procedidas retenções (2) mecânicas para fixação por meio de colagem na face lingual dos caninos (3) inferiores, com resina composta, de modo que no interior da "fêmea" (1) é provido um orifício (4) para o encaixe do "macho" (5) e, no centro da cavidade é provido um anel (6) elástico que se encaixa precisamente numa canaleta feita no pino (7) de encaixe do "macho" (5), sendo que, na extremidade dos "machos" (5) podem existir prolongamentos (8) metálicos para retenção de acrílico (9) ou então meios de encaixe para soldagem de um fio metálico (10) espesso, que contorna a face lingual dos dentes (11); inferiores anteriores, de modo que, quando se optar pela retenção em acrilico (9), um fio metálico (10) mais delgado é soldado no terminal de encaixe do "macho" (5) e logo após, o fio (10) e o terminal são recobertos por acrilico (9), sendo que os "machos" (5) poderão ter angulações nos braços (12) de encaixes.

Influência da dentina bovina e do dispositivo de microtração na resistência de união de sistemas adesivos

Pós-graduação em Odontologia Restauradora - ICT