Papers by Leandro Martins
Operative Dentistry, 2020
SUMMARY Objectives: This study aimed to evaluate the desensitizing effect of a prefilled disposab... more SUMMARY Objectives: This study aimed to evaluate the desensitizing effect of a prefilled disposable tray containing potassium nitrate and fluoride on the self-reported tooth sensitivity (TS) and the bleaching efficacy of 40% hydrogen peroxide bleaching agent used for in-office bleaching in comparison with potassium nitrate and fluoride gel applied in a conventional-delivered tray system in an equivalence clinical trial. Methods and Materials: Seventy-eight patients, with a right maxillary canine darker than A3, were selected for this single-blind (evaluators), randomized clinical trial. Teeth were bleached in two sessions with a one-week interval in between. Before in-office bleaching, the prefilled disposable tray or conventional tray containing potassium nitrate and fluoride was used for 15 minutes. Subsequently, the bleaching agent was applied in two 20-minute applications (per the manufacturer's directions) in each session. The color change was evaluated by subjective (Vita ...
Research, Society and Development, 2021
Objective: To assess the color change of bovine enamel after tooth bleaching while using orthodon... more Objective: To assess the color change of bovine enamel after tooth bleaching while using orthodontic brackets. Methodology: This in vitro study selected 48 bovine incisors without visible fractures or cracks (cut in blocks of 8x12x3 mm). They were distributed in four groups: no staining and with brackets (NSWB), no staining and no brackets (NSNB), with staining and brackets (WSWB), and with staining and no brackets (WSNB) (n=12). The color was initially assessed with a spectrophotometer for NS (no staining). The teeth in WS (with staining) groups were immersed in an instant coffee solution for 15 days and the initial color was also assessed. After prophylaxis and adhesive treatment, the brackets were bonded to the teeth. The teeth were bleached with 35% hydrogen peroxide and the color was analyzed 30 days after bleaching. A two-way Analysis of Variance was applied as well as a subsequent multiple comparison analysis (p>0.05). Results: According to the data obtained, the factor of...
Innovations Implant Journal, Apr 1, 2010
Objectives: The purpose in this study was to compare the fluorescence between dental structures (... more Objectives: The purpose in this study was to compare the fluorescence between dental structures (enamel and dentin) and three composite resins using a digital image. Methods: Three composite resins (Esthet-X, Dentsply; Filtek Z-350, 3M/ESPE and 4-Seasons, Ivoclar Vivadent), enamel and dentin shade A2, and three sound human teeth were used. A sagittal slice of 2mm width was obtained from each tooth, removing the palatal enamel and dentin. The slice was positioned in a stainless steel matrix to fill the enamel and dentin with the correspondent resin composite. The space restored with the composite resin was 10X10X2mm. Three teeth for each resin composite were used. An ultraviolet LED source was applied directly to the specimen in a dark room. Fluorescence of enamel resin, enamel, dentin and dentin resin were measured with digital images processed through a computer program developed by So Carlos Physics Institute-Optical Group, USP - Brazil. The computer program rates in pixels the fl...
Objective: This study sought to assess the effect of airborne-particle abrasion (50µm Al2O3 parti... more Objective: This study sought to assess the effect of airborne-particle abrasion (50µm Al2O3 particles - Jat) on shear bond strength when two primers (Alloy Primer – Ap, Metal/Zircônia Primer - Mz) and two resin luting agents (Panavia F – Pa, RelyX U100 - RU) were used on the zirconia. Method: 120 rectangular samples of zirconia were randomly divided into 12 groups (n=10) according to the surface treatments. The resin cements were applied into a Teflon mold directly onto zirconia surface. After the cementation, the samples were stored in distilled water at 37°C for 24 hours prior to the test, which was carried out in a universal testing machine (EMIC) at a cross-speed of 0.5mm/min. Light stereomicroscope and scanning electron microscope were employed to inspect the failure mode. The data were first analyzed by one-way ANOVA (p<0.05) and Tukey test, regardless of the treatment and the luting system. Then, two-way ANOVA (surface treatment vs luting system) and the Tukey test were ap...
Objectives: To evaluate the regional bond strength of glass fiber posts cemented to root dentin w... more Objectives: To evaluate the regional bond strength of glass fiber posts cemented to root dentin with two different resin cements and adhesive systems, using the push-out test. Material and methods: Fifteen single-rooted bovine teeth with standardized root canal instrumentation were randomly assigned to 3 groups (n=5): G1- etching with 37% phosphoric acid gel (3M/ESPE) + Adper ScotchBond Multi Purpose Plus (3M/ESPE) light cured + #2 glass fiber post (Exacto C Angelus) + conventional resin cement RelyX ARC (3M/ESPE); G2- etching with 37% phosphoric acid gel + Adper ScotchBond Multi Purpose Plus (3M/ESPE) chemically cured + #2 glass fiber post + RelyX ARC (3M/ESPE); G3- #2 glass fiber post + self adhesive resin cement RelyX U100 (3M/ESPE). After 24 hour storage in distilled water at 37C, specimens were cut into thin slices of 1mm thick and submitted to the push-out test in a universal testing machine (EMIC) at a crosshead speed of 0.5 mm/min. Results: Cementation material had a signifi...
Objective: This study aims to evaluate by surface microhardness analysis the in vitro preventive ... more Objective: This study aims to evaluate by surface microhardness analysis the in vitro preventive potential of a sodium fluoride (Colgate®) and a sodium fluoride and potassium nitrate (Pronamel/Sensodyne®) composed toothpastes on the enamel, after short term (7 days) Coca-Cola® erosive challenge. Method: 60 bovine enamel blocks were distributed into six groups according to the treatment (n=10): G1- erosion with Coca-Cola® and treatment with Pronamel® toothpaste; G2- treatment with Pronamel® toothpaste, G3- erosion with Coca-Cola® and treatment with fluoridated toothpaste (Colgate®); G4- treatment with Colgate® toothpaste; G5- artificial saliva (negative control); and G6- erosion with Coca-Cola® (positive control). The response variable was the change of surface microhardness performed on day 7. Knoop microhardness (25g, 5”) was assessed initially, with three indentations performed with 100 µm distance between them. The specimens were submitted to pH cycling for 7 days. Each day consi...
2010 Abstracts IEEE International Conference on Plasma Science, 2010
ABSTRACT
ABSTRACT Objective: This study aimed to assess the influence of 2% chlorhexidine digluconate (CHX... more ABSTRACT Objective: This study aimed to assess the influence of 2% chlorhexidine digluconate (CHX) in order to bond glass fiber post using different categories of dentin bonding system (DBS). The tested null hypotheses were that there is no difference on bond strength regarding the tested DBS, the application of CHX and the distance from cervical area. Methods: Sixty bovine roots were selected and stored in renewed 0.1% thymol solution. After standardized endodontic treatment and obturation, they were randomly assigned into 6 groups: G1- SBMP (Scothbond Multi Purpose), G2- SB (Single Bond 2), G3- SE (Clearfil SE Bond). G4 to G6 were respectively similar to the previous studies but associated to CHX. Following, all the groups were restored with glass fiber post Exacto (Angelus) and fixed with dual cure resin cement RelyX ARC. After 1 week, the specimens were perpendicularly cut to obtain 1mm-thick specimens to be tested by push-out. Modes of failure were analyzed by optical microscopy (40x). Statistical analysis were performed by ANOVA and Tukey tests (α=0.05). Results: The effect of bonding system was significant, which was not to thirds except for SE-CHX. SE reached greater bond strength. Values of means and standard deviations of bonding resistance (MPa) for cervical, median and apical regions were: SBMP- 5.73 (2.55), 4.61 (2.56), 4.2 (2.88); SBMP-CHX-6.16 (2.49), 5.0 (3.67), 3.84 (1.82); SB- 2.29 (1.54), 2.77 (2.14), 3.29 (2.08); SB-CHX-2.43 (1.65), 1.87 (1.06), 1.98 (1.12); SE- 8.59 (1.72), 6.90 (2.89), 7.04 (1.40) and SE-CHX- 6.09 (2.85), 3.72 (2.02), 1.83 (1.38). Regardless of the group, adhesive failure between liner and dentin was predominant. Conclusions: No improvement was evident to bond strength of fiber post to endodontic treated root. The performance was material-dependent, and two-step self-etching system was superior in all situations. However, CHX affected it negatively.
Cerâmica, 2010
Os sistemas cerâmicos representam hoje na odontologia uma alternativa aos metais no tratamento pr... more Os sistemas cerâmicos representam hoje na odontologia uma alternativa aos metais no tratamento protético. No entanto, esses materiais não atingiram os mesmos resultados a longo prazo da convencional prótese metalocerâmica. Na maioria dos casos, principalmente em próteses anteriores, o comportamento desses materiais é satisfatório. Entretanto, à medida que a demanda por estética exige a utilização de materiais cerâmicos nas regiões posteriores, as taxas de falhas aumentam. Com isso, sabendo o que se pode esperar de cada material é possível não só indicar ou contra-indicar a utilização destas próteses, mas também desenvolver novos materiais e técnicas. O objetivo desta revisão foi apresentar os diversos sistemas cerâmicos e seu comportamento mecânico durante a utilização clínica, relatando as localizações, os tipos e as regiões das falhas mais frequentes nos sistemas atuais, visando à busca por soluções.
Operative Dentistry, 2012
SUMMARY Objectives This study evaluated the effect of an alkaline solution and two 10-methacryloy... more SUMMARY Objectives This study evaluated the effect of an alkaline solution and two 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based primer agents on bond strength to zirconia (yttria-stabilized tetragonal zirconium polycrystal [Y-TZP]) through the shear bond strength (SBS) test. Materials and Methods Sixty square-shaped Y-TZP samples were embedded in an acrylic resin mold, polished, and randomly assigned to one of six groups (n=10) according to treatment surface: group CR, no treatment (control); group NaOH, 0.5 M NaOH; group AP, Alloy Primer; group ZP, Z-Primer Plus; group NaOH-AP, 0.5 M NaOH + Alloy Primer; and group NaOH-ZP, 0.5 M NaOH + Z-Primer Plus. The resin cement (Rely X U100) was applied inside a matrix directly onto the Y-TZP surface, and it was light-cured for 40 seconds. The samples were stored in distilled water at 37°C for 24 hours prior to the test, which was performed in a universal machine at a crosshead-speed of 0.5 mm/min. The data were analyzed by one-wa...
Laser Physics, 2009
... to thank: 3M/ESPE Brazil for providing the nanofilled composite resin used in this study; ... more ... to thank: 3M/ESPE Brazil for providing the nanofilled composite resin used in this study; Labordental Brazil for providing the light curing unit (Optilux 501/Kerr) used in this study; Dr. Milko Javier Villarroel Cortes ... LG Lopes, EB Franco, JC Pereira, and RFL Mondelli, J. Appl. ...
The Journal of the American Dental Association, 2009
N oncarious cervical lesions (NCCLs) are pathological processes of dental wear of multifactorial ... more N oncarious cervical lesions (NCCLs) are pathological processes of dental wear of multifactorial etiology independent of bacteria. They are classified according to etiology as erosion, abrasion/corrosion or abfraction. However, because different etiologic factors may act together to promote the same lesion, the cause of these lesions may be multifactorial. 1-5 These lesions can occur in young patients and become more frequent as the patient ages. The prevalence of such lesions is high in premolars, and the shape of the lesion reflects the factors that contributed to its formation. 6 Some authors suggest that occlusal load plays a primary role in the development of NCCLs. 7,8 According to the theory of dental flexure, masticatory or abnormal loads, when applied in areas of hyperfunction or malocclusion, may expose one or more teeth to an extreme force. This force focuses on the cementoenamel junction (CEJ), where it can cause microfractures in enamel and dentin. These micro
Journal of Prosthodontics, 2012
Purpose: The purpose of this study was to test the hypothesis that all-ceramic crown core-veneer ... more Purpose: The purpose of this study was to test the hypothesis that all-ceramic crown core-veneer system reliability is improved by modifying the core design and as a result is comparable in reliability to metal-ceramic retainers (MCR). Finite element analysis (FEA) was performed to verify maximum principal stress distribution in the systems. Materials and Methods: A first lower molar full crown preparation was modeled by reducing the height of proximal walls by 1.5 mm and occlusal surface by 2.0 mm. The CAD-based preparation was replicated and positioned in a dental articulator for specimen fabrication. Conventional (0.5 mm uniform thickness) and modified (2.5 mm height, 1 mm thickness at the lingual extending to proximals) zirconia (Y-TZP) core designs were produced with 1.5 mm veneer porcelain. MCR controls were fabricated following conventional design. All crowns were resin cemented to 30-day aged composite dies, aged 14 days in water and either single-loaded to failure or step-stress fatigue tested. The loads were positioned either on the mesiobuccal or mesiolingual cusp (n = 21 for each ceramic system and cusp). Probability Weibull and use level probability curves were calculated. Crack evolution was followed, and postmortem specimens were analyzed and compared to clinical failures. Results: Compared to conventional and MCRs, increased levels of stress were observed in the core region for the modified Y-TZP core design. The reliability was higher in the Y-TZP-lingual-modified group at 100,000 cycles and 200 N, but not significantly different from the MCR-mesiolingual group. The MCR-distobuccal group showed the highest reliability. Fracture modes for Y-TZP groups were veneer chipping not exposing the core for the conventional design groups, and exposing the veneer-core interface for the modified group. MCR fractures were mostly chipping combined with metal coping exposure. Conclusions: FEA showed higher levels of stress for both Y-TZP core designs and veneer layers compared to MCR. Core design modification resulted in fatigue reliability response of Y-TZP comparable to MCR at 100,000 cycles and 200 N. Fracture modes observed matched with clinical scenarios.
Journal of Prosthodontics, 2013
This evaluation aimed to (1) validate micro-computed tomography (microCT) findings using scanning... more This evaluation aimed to (1) validate micro-computed tomography (microCT) findings using scanning electron microscopy (SEM) imaging, and (2) quantify the volume of voids and the bonded surface area resulting from fiber-reinforced composite (FRC) dowel cementation technique using microCT scanning technology/3D reconstructing software. A fiberglass dowel was cemented in a condemned maxillary lateral incisor prior to its extraction. A microCT scan was performed of the extracted tooth creating a large volume of data in DICOM format. This set of images was imported to image-processing software to inspect the internal architecture of structures. The outer surface and the spatial relationship of dentin, FRC dowel, cement layer, and voids were reconstructed. Three-dimensional spatial architecture of structures and volumetric analysis revealed that 9.89% of the resin cement was composed of voids and that the bonded area between root dentin and cement was 60.63% larger than that between cement and FRC dowel. SEM imaging demonstrated the presence of voids similarly observed using microCT technology (aim 1). MicroCT technology was able to nondestructively measure the volume of voids within the cement layer and the bonded surface area at the root/cement/FRC interfaces (aim 2). The interfaces at the root dentin/cement/dowel represent a timely and relevant topic where several efforts have been conducted in the past few years to understand their inherent features. MicroCT technology combined with 3D reconstruction allows for not only inspecting the internal arrangement rendered by fiberglass adhesively bonded to root dentin, but also estimating the volume of voids and contacted bond area between the dentin and cement layer.
Journal of Dentistry, 2010
Metal ceramic restorations (MCR) are considered the standard treatment for crowns and fixed parti... more Metal ceramic restorations (MCR) are considered the standard treatment for crowns and fixed partial dentures. 1 Adverse esthetic concerns regarding the grayish discoloration at the gingival margin and possible exposition of the metal framework margin, if recession may occur, have been the power engine in all-ceramic materials development. 2 All-ceramic restorations are an attractive material in dentistry because of their esthetics and biocompatibility. 3 However, when j o u r n a l o f d e n t i s t r y 3 8 (2 0 1 0) 6 2 6-6 3 4
Journal of Applied Oral Science, 2012
In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP-IPS e.max ZirCAD), a... more In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP-IPS e.max ZirCAD), and metal-ceramic (MC-Ni-Cr alloy) crowns. Material and 0HWKRGV 6L[W\ VWDQGDUGL]HG UHVLQWRRWK UHSOLFDV RI D PD[LOODU\ ¿UVW PRODU ZHUH SURGXFHG for crown placement and divided into 3 groups (n=20 each) according to the core material used (metal, ICA or Y-TZP). The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS), axial space (AS) and total mean (TM) using two-way ANOVA with Tukey's multiple comparison test (p<0.05). Results: No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, 26 DQG 70 VKRZHG VLJQL¿FDQWO\ KLJKHU YDOXHV IRU ,&$ DQG <7=3 JURXSV WKDQ 0& JURXS &RPSDULVRQV RI ,&$ DQG <7=3 UHYHDOHG WKDW 26 ZDV VLJQL¿FDQWO\ ORZHU IRU <7=3 JURXS whereas no differences were observed for TM. Conclusions: The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group GHPRQVWUDWHG VLJQL¿FDQWO\ ORZHU YDOXHV WKDQ WKH DOOFHUDPLF JURXSV HVSHFLDOO\ LQ 26
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Papers by Leandro Martins