Alvaro Della Bona - University of Passo Fundo (Brazil) (original) (raw)

Papers by Alvaro Della Bona

Research paper thumbnail of Propriedades físicas dos fios de sutura usados na odontologia

Brazilian dental science, Aug 13, 2010

Objetivo: investigar as características físicas dos fios de sutura freqüentemente usados na odont... more Objetivo: investigar as características físicas dos fios de sutura freqüentemente usados na odontologia. Material e Método: Fios (n=10) de seda (FS) 4-0 e nylon (FN) 4-0 (Somerville Ltda.) foram testados de acordo com a norma NBR 13904:2003. O comprimento foi determinado com escala rígida, sem tensionar o fio. O diâmetro foi avaliado utilizando um metroscópio e um relógio comparador digital. As cargas de ruptura em tração sobre nó (L no) e ao encastoamento (L f) foram testados em uma máquina de ensaio universal com velocidade de 1mm/min. Os resultados foram analisados estatisticamente pelo teste t de Student (α = 0,05). Resultados: Todos os fios cumpriram com as especificações quanto ao comprimento. Os FN apresentaram um valor médio de diâmetro de 0,17 mm, contudo os FS apresentaram um valor médio de 0,21 mm, ficando fora da faixa específica (0,15-0,199 mm). Valores médios de L no foram significativamente maiores para os FS (7,54 ± 0,50 N) do que para os FN (6,67 ± 0,83 N) (p<0,05). Todos os fios resistiram ao teste de encastoamento com valores acima dos limites individual e médio mínimos preconizados, respectivamente 2,26 N e 4,41 N, sendo que os valores médios de FS (8,98 ± 2,16 N) foram significativamente maiores do que os FN (7,27 ± 1,31 N) (p<0,05). Conclusão: Essas diferenças podem ter sido induzidas pelo maior diâmetro dos FS, pois assumindo os valores médios de diâmetro e carga obtem-se valores de resistência a tração sobre nó (σ no) de 203,

Research paper thumbnail of Evidências ciEntíficas para a adEsão dE bráquEtEs cErâmicos a difErEntEs substratos odontológicos Scientific evidences for bonding of ceramic brackets to different dental substrates

Evidências ciEntíficas para a adEsão dE bráquEtEs cErâmicos a difErEntEs substratos odontológicos Scientific evidences for bonding of ceramic brackets to different dental substrates

Evidências cien-tíficas para a adesão de bráquetes cerâmicos a diferentes substratos odontológico... more Evidências cien-tíficas para a adesão de bráquetes cerâmicos a diferentes substratos odontológicos. SALUSVITA, Bauru, v. 33, n. 3, p. 365-387, 2014. rEsumo Introdução: Existe uma grande demanda por tratamento ortodôntico em pacientes adultos, que requerem frequentemente uma adequada adesão de bráquetes a vários substratos, além do esmalte dental, tais como: porcelanas, ligas metálicas, amálgama, ouro, dentina, resinas compostas e acrílicas. Objetivo: Apresentar revisão da literatura so-bre os mecanismos adesivos empregados para a adesão de bráquetes cerâmicos aos diversos substratos encontrados na clínica odontoló-gica e as propriedades dos bráquetes cerâmicos, sugerindo proto-colos adesivos com base em evidências. Métodos: A pesquisa foi realizada na base de dados PubMed, em artigos publicados a partir de 1986, incluindo aos temas: bráquetes cerâmicos e resistência de união em ortodontia. Resultados: A estética e a biocompatibilidade foram reportadas como as maiores vantagens dos b...

Research paper thumbnail of Effect of ceramic surface treatment on tensile bond strength to a resin cement

Effect of ceramic surface treatment on tensile bond strength to a resin cement

The International journal of prosthodontics

The objective of this study was to test the following hypotheses: (1) hydrofluoric acid (HF)-trea... more The objective of this study was to test the following hypotheses: (1) hydrofluoric acid (HF)-treated ceramic surfaces produce the highest tensile bond strength to resin cements, independent of the ceramic microstructure and composition; and (2) the tensile bond strength test is appropriate for analysis of interfacial adhesion for ceramic-bonded-to-resin systems. Ceramic specimens were polished with 1-micron alumina abrasive and divided into four groups of 10 specimens for each of seven ceramic types. One of the following surface treatments was applied: (1) 10% ammonium bifluoride (ABF) for 1 minute; (2) 9.6% HF for 2 minutes; (3) 4% acidulated phosphate fluoride (APF) for 2 minutes; and (4) a silane coupling agent. The surface-treated areas were coated with an adhesive resin and bonded to a resin cement. Specimens were loaded to failure in tension using a testing machine. Tensile bond strength data were statistically analyzed, and fracture surfaces were examined to determine the mod...

Research paper thumbnail of Modes of Failure of Bonding Interfaces in Dentistry

Modes of Failure of Bonding Interfaces in Dentistry

Ceramic Transactions, 2012

Research paper thumbnail of Influence of ceramic pre-treatments on tensile bond strength and mode of failure of resin bonded to ceramics

Influence of ceramic pre-treatments on tensile bond strength and mode of failure of resin bonded to ceramics

American journal of dentistry, 2007

To evaluate the effect of ceramic surface treatments on tensile bond strength (sigma) and the mod... more To evaluate the effect of ceramic surface treatments on tensile bond strength (sigma) and the mode of failure of a resin bonded to a feldspathic glass and a low-crystalline ceramic, testing the hypothesis that a silica coating treatment is unnecessary for both the glass and the low-crystalline ceramic. 10 blocks of each the feldspathic glass (V7-VITAVM7) and the leucite-based ceramic (E1-IPS Empress) were fabricated and polished. Five blocks of each ceramic were treated as follows: 9.5% hydrofluoric acid for 60 seconds; and silica coating using Cojet System for 15 seconds. After silane coating, an adhesive resin and a composite were applied and polymerized. The composite-ceramic blocks were cut to produce bar-shaped specimens (n = 30) that were stored in distilled water at 37 degrees C for 7 days before tensile loading to failure in a universal testing machine. Data were statistically analyzed using analysis of variance, Tukey's test (alpha = .01) and Weibull analysis. Fracture ...

Research paper thumbnail of Contributions of stress corrosion and cyclic fatigue to subcritical crack growth in a dental glass-ceramic

Dental Materials, 2014

Objective-The objective of this study was to test the following hypotheses: 1. Both cyclic degrad... more Objective-The objective of this study was to test the following hypotheses: 1. Both cyclic degradation and stress-corrosion mechanisms result in subcritical crack growth (SCG) in a fluorapatite glass-ceramic (IPS e.max ZirPress, Ivoclar-Vivadent). 2. There is an interactive effect of stress corrosion and cyclic fatigue to accelerate subcritical crack growth. Methods-Rectangular beam specimens were fabricated using the lost-wax process. Two groups of specimens (N=30/group) with polished (15 µm) or air-abraded surface were tested under rapid monotonic loading. Additional polished specimens were subjected to cyclic loading at two frequencies, 2 Hz (N=44) and 10 Hz (N=36), and at various stress amplitudes. All tests were performed using a fully articulated four-point flexure fixture in deionized water at 37°C. The SCG parameters were determined using the ratio of inert strength Weibull modulus to lifetime Weibull modulus. A general log-linear model was fit to the fatigue lifetime data including time to failure, frequency, peak stress, and the product of frequency and logarithm of stress in ALTA PRO software. Results-SCG parameters determined were n=21.7 and A=4.99×10−5 for 2 Hz, and n=19.1 and A=7.39×10−6 for 10 Hz. After fitting the general log-linear model to cyclic fatigue data, the coefficients of the frequency term (α1), the stress term (α2), and the interaction term (α3) had estimates and 95% confidence intervals of α1= −3.16 (−15.1, 6.30), α2= −21.2 (−34.9, −9.73), and α3= 0.820 (−1.59, 4.02). Only α2 was significantly different from zero.

Research paper thumbnail of Atendimento odontológico de pacientes surdo-cegos: enfrentando desafios

Revista da Faculdade de Odontologia - UPF, 2013

Research paper thumbnail of Efficacy and Safety of 10% and 16% Carbamide Peroxide Tooth-whitening Gels: A Randomized Clinical Trial

Operative Dentistry, 2008

Clinical Relevance This clinical trial suggests that two carbamide peroxide concentrations, when ... more Clinical Relevance This clinical trial suggests that two carbamide peroxide concentrations, when used once a day for three weeks, were well tolerated by patients and were effective in tooth whitening. Although some tooth sensitivity occurred during treatment, this side effect was mostly mild and transient.

Research paper thumbnail of The effect of ceramic surface treatment on bonding to densely sintered alumina ceramic

The effect of ceramic surface treatment on bonding to densely sintered alumina ceramic

The Journal of Prosthetic Dentistry, 2005

Ceramic surface treatment is crucial for bonding to resin. High crystalline ceramics are poorly c... more Ceramic surface treatment is crucial for bonding to resin. High crystalline ceramics are poorly conditioned using traditional procedures. The purpose of this study was to evaluate the effect of silica coating on a densely sintered alumina ceramic relative to its bond strength to composite, using a resin luting agent. Material and methods Blocks (6 x 6 x 5 mm) of ceramic and composite were made. The ceramic (Procera AllCeram) surfaces were polished, and the blocks were divided into 3 groups (n = 5): SB, airborne-particle abrasion with 110-microm Al 2 O 3 ; RS, silica coating using Rocatec System; and CS, silica coating using CoJet System. The treated ceramic blocks were luted to the composite (W3D Master) blocks using a resin luting agent (Panavia F). Specimens were stored in distilled water at 37 degrees C for 7 days and then cut in 2 axes, x and y, to obtain specimens with a bonding area of approximately 0.6 mm 2 (n = 30). The specimens were loaded to failure in tension in a universal testing machine, and data were statistically analyzed using a randomized complete block design analysis of variance and Tukey&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s test (alpha=.05). Fractured surfaces were examined using light microscopy and scanning electron microscopy to determine the type of failure. Energy-dispersive spectroscopy was used for surface compositional analysis. Mean bond strength values (MPa) of Groups RS (17.1 +/- 3.9) ( P =.00015) and CS (18.5 +/- 4.7) ( P =.00012) were significantly higher than the values of Group SB (12.7 +/- 2.6). There was no statistical difference between Groups RS and CS. All failures occurred at the adhesive zone. Tribochemical silica coating systems increased the tensile bond strength values between Panavia F and Procera AllCeram ceramic.

Research paper thumbnail of Removal of partially or fully polymerized resin from porcelain veneers

Removal of partially or fully polymerized resin from porcelain veneers

The Journal of Prosthetic Dentistry, 1993

Research paper thumbnail of A Variety of Patient Factors may Influence Porcelain Veneer Survival Over a 10-Year Period

A Variety of Patient Factors may Influence Porcelain Veneer Survival Over a 10-Year Period

Journal of Evidence Based Dental Practice, 2010

Clinical records were reviewed for more than 80,000 different patients from the General Dental Se... more Clinical records were reviewed for more than 80,000 different patients from the General Dental Services (GDS) in England and Wales. A total of 2562 porcelain veneer restorations were placed in 1177 adult patients (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or =18 years old, 35% male and 65% female) over a period of 11 years (January, 1991, to March, 2002). A number of factors were considered potentially capable of impacting the need for reintervention on teeth restored with porcelain veneers. These included a number of patient factors such as gender, age, and dental utilization practices. Other factors analyzed included the tooth position receiving veneers, dentists&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; qualifications, and where and when the veneer was placed (eg, month and geographic location). The main outcome was survival over 10 years between initial placement and the first date of intervention for each tooth treated with a porcelain veneer. Information was abstracted from clinical records to create an analytical dataset of porcelain veneers, with their dates of placement and their dates, if any, of reintervention. This dataset was analyzed using a modified Kaplan-Meier statistic and a Cox-regression model. Factors that were found to influence the survival of porcelain veneers included the following: gender, with veneers placed in male patients surviving for less time than those placed for female patients (P = .01); patient age, with poorer survival of porcelain veneers in older (60 years or older) patients (P = .003); changing dentist, with teeth of patients who change dentist surviving for shorter periods of time to reintervention than for those patients who continue in the care of the same dentist (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001); patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s treatment need, with patients whose gross annual fees on all dental treatment are higher having teeth with less time to reintervention after receiving veneers than those patients with lower annual fees (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001); patient paying status, with patients who are exempt from charges also having veneered teeth with shorter time to reintervention (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.001). Nevertheless, the factors associated with tooth position or mouth quadrant and with the dentist (gender, age, years since graduation, and country of qualification) did not influence the survival rate. Although dentist factors do not appear to play a part, a variety of patient factors have been found to influence veneer survival to reintervention.…

Research paper thumbnail of Effect of endodontic sealers on tooth color

Journal of Dentistry, 2013

Research paper thumbnail of Effect of acid etching of glass ionomer cement surface on the microleakage of sandwich restorations

Journal of Applied Oral Science, 2007

he purposes of this study were to evaluate the sealing ability of different glass ionomer cements... more he purposes of this study were to evaluate the sealing ability of different glass ionomer cements (GICs) used for sandwich restorations and to assess the effect of acid etching of GIC on microleakage at GIC-resin composite interface. Forty cavities were prepared on the proximal surfaces of 20 permanent human premolars (2 cavities per tooth), assigned to 4 groups (n=10) and restored as follows: Group CIE-conventional GIC (CI) was applied onto the axial and cervical cavity walls, allowed setting for 5 min and acid etched (E) along the cavity margins with 35% phosphoric acid for 15 s, washed for 30 s and water was blotted; the adhesive system was applied and light cured for 10 s, completing the restoration with composite resin light cured for 40 s; Group CIN-same as Group CIE, except for acid etching of the CI surface; Group RME-same as CIE, but using a resin modified GIC (RMGIC); Group RMN-same as Group RME, except for acid etching of the RMGIC surface. Specimens were soaked in 1% methylene blue dye solution at 24ºC for 24 h, rinsed under running water for 1 h, bisected longitudinally and dye penetration was measured following the ISO/TS 11405-2003 standard. Results were statistically analyzed by Kruskal-Wallis and chi-square tests (α=0.05). Dye penetration scores were as follow: CIE-2.5; CIN-2.5; RME-0.9; and RMN-0.6. The results suggest that phosphoric acid etching of GIC prior to the placement of composite resin does not improve the sealing ability of sandwich restorations. The RMGIC was more effective in preventing dye penetration at the GIC-resin compositedentin interfaces than CI.

Research paper thumbnail of Radiographic evaluation of furcal perforations sealed with different materials in dogs' teeth

Journal of Applied Oral Science, 2011

The objective of this work was to evaluate, using radiographic images, the behavior of four mater... more The objective of this work was to evaluate, using radiographic images, the behavior of four materials used to repair root perforations in dogs' teeth. Material and Methods: Second and third premolars of 6 dogs were used. The 48 teeth were randomly divided into 4 groups (n=12) and the perforations were sealed with one of the following materials: MTA, AH Plus, Vitremer and gutta-percha. Dogs were submitted to general anesthesia, teeth were radiographed and pulp was accessed. Perforations were done, at WKH PD[LPXP FXUYH RI WKH SXOS ÀRRU VHDOHG DQG WKH DFFHVVHG FRURQDO FDYLW\ ZDV ¿OOHG ZLWK JODVV LRQRPHU FHPHQW 9LGULRQ 5 $IWHU GD\V WKH GRJV ZHUH VDFUL¿FHG DQG WKH last x-ray image was taken. Images were analyzed for the presence/absence of periodontal lesions at the perforation region. Data were analyzed statistically by chi-square test at VLJQL¿FDQFH OHYHO 5HVXOWV 7KHUH ZHUH QR VWDWLVWLFDOO\ VLJQL¿FDQW GLIIHUHQFHV S among AH Plus, Vitremer and gutta-percha groups. MTA produced the smallest number of periodontal lesions (p<0.05). Conclusions: It may be concluded that none of the tested materials was able to preserve the integrity of the periodontal tissues in the furcation region, and the use of MTA resulted in the least formation of adjacent periodontal bone lesions revealed by the radiographic comparisons.

Research paper thumbnail of Characterizing ceramics and the interfacial adhesion to resin: II- the relationship of surface treatment, bond strength, interfacial toughness and fractography

Journal of Applied Oral Science, 2005

The clinical success of resin bonding procedures for indirect ceramic restorations and ceramic re... more The clinical success of resin bonding procedures for indirect ceramic restorations and ceramic repairs depends on the quality and durability of the bond between the ceramic and the resin. The quality of this bond will depend upon the bonding mechanisms that are controlled in part by the surface treatment that promote micromechanical and/or chemical bonding to the substrate. The objective of this review is to correlate interfacial toughness (K A) with fracture surface morphological parameters of the dental ceramic-resin systems as a function of ceramic surface treatment. This analysis is designed to identify mechanisms that promote adhesion of these ceramic-resin systems and an appropriate bond test method to yield relevant adhesion performance data.

Research paper thumbnail of Microbial leakage and apical inflammatory response in dog's teeth after root canal filling with different sealers, post space preparation and exposure to the oral environment

Journal of Applied Oral Science, 2007

oronal leakage is an important factor affecting the outcome of endodontic therapy. This study eva... more oronal leakage is an important factor affecting the outcome of endodontic therapy. This study evaluated the microbial leakage (ML) and the apical inflammatory response (AIR) in dog's teeth after root canal filling with three endodontic sealers, post preparation and exposure to the oral environment, testing the hypothesis that there is a positive correlation between these two histological parameters (ML and AIR). Sixty-four root canals of 8 mongrel dogs were cleaned, shaped and randomly distributed into groups according to the sealer to be used: Sealer 26 (n=18); AH Plus (n=18); RoekoSeal (n=19); no sealercontrol group (n=9). Root canals were filled by the lateral condensation technique. Post space preparation left 4 mm of filling material in the apical root third, and specimens were exposed to the oral environment for 90 days. The dogs were killed and jaw blocks were histologically processed using Brown & Brenn and HE staining techniques. ML and AIR were scored from 1 to 4. Results were analyzed statistically using ANOVA, Duncan's post-hoc test and Spearman's correlation. ML and AIR score means were: Sealer 26-2.44±0.98 and 2.50±0.70; AH Plus-2.50±0.78 and 2.22±0.54; RoekoSeal-1.84±0.95 and 2.63±0.83; Control-2.56±1.23 and 3.11±0.60. Statistically significant differences in AIR scores were found between the AH Plus and control groups (p<0.05). Although RoekoSeal had the lowest ML means, and AH Plus, the lowest AIR means after 90-day exposure to the oral environment, no statistically significant differences were found between the three sealers under study, and no correlation was found between ML and AIR.

Research paper thumbnail of Evaluation of Melia azedarach Extracts against American Bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

Entomologia Generalis, 2012

Melia azedarach (Linnaeus 1753) drupes and green leaves extracts (methanol and chloroform:methano... more Melia azedarach (Linnaeus 1753) drupes and green leaves extracts (methanol and chloroform:methanol) were evaluated against American bollworm, Helicoverpa armigera (Hubner 1806). Various concentrations of extracts were used to treat natural foods, viz leaves and pods/bolls of chickpea, pigeonpea, and cotton. Treated foods were offered to early stage (neonate) and advanced stage (grown up) larvae of H armigera for 48 h, and then, untreated food was offered for the rest of life. Chloroform:methanol (9:1) extracts of M azedarach drupes and leaves showed better insecticidal properties than methanol extracts. However, M azedarach drupes extract in chloroform:methanol (9:1) was the most promising in causing adverse morphogenic effect on various biological parameters of H armigera. Early stage larvae were more sensitive to the exposure of M azedarach extracts than advanced stage larvae.

Research paper thumbnail of Visual and instrumental agreement in dental shade selection: Three distinct observer populations and shade matching protocols

Dental Materials, 2009

Objectives. This study tested the hypothesis that the agreement between observer visual dental sh... more Objectives. This study tested the hypothesis that the agreement between observer visual dental shade matches and instrumental shade identification is higher using the Vita 3D-Master ® (3D) shade guide than the Vita classical (VC) shade guide. Methods. Three populations selected shade matches: non-dental observers (GP) matched shade tabs-to-tabs and dental students (DS) and dentists (DD) matched an in vivo natural right upper central incisor (RUCI). All observers (n = 600) used both shade guides (3D and VC) in two lighting conditions, cool white fluorescent lighting (CWF) and natural sunlight (NSL). The shade tabs and natural teeth were identified using an intra-oral spectrophotometer (Vita Easyshade TM) to determine the instrumental agreement with the visual shade selection. The percent visual-instrumental shade agreement (PVIA) was analyzed statistically considering: observer population, shade guide set, and lighting condition. Results. A "substantial" intra-examiner agreement (k = 0.76) was observed. The PVIA ranged from 12% (DS) for the 3D-NSL condition to 42% (DD) with the VC-CWF condition, which also resulted in the highest PVIA for GP (38.5%) and DS (35%). Results indicated that the GP with neither dental knowledge nor shade guide experience had a significantly higher PVIA using the VC rather than the 3D shade guide. Dentists demonstrated the highest PVIA (42%) for both lighting conditions and shade guides, thereby rejecting the study hypothesis. Significance. A significantly higher visual-instrumental shade agreement was demonstrated by the clinically experienced dentists (DD), regardless of shade guides and lighting conditions.

Research paper thumbnail of Mechanical strength and subcritical crack growth under wet cyclic loading of glass-infiltrated dental ceramics

Dental Materials, 2010

Objectives. Evaluate the flexural strength () and subcritical crack growth (SCG) under cyclic loa... more Objectives. Evaluate the flexural strength () and subcritical crack growth (SCG) under cyclic loading of glass-infiltrated alumina-based (IA, In-Ceram Alumina) and zirconia-reinforced (IZ, In-Ceram Zirconia) ceramics, testing the hypothesis that wet environment influences the SCG of both ceramics when submitted to cyclic loading. Methods. Bar-shaped specimens of IA (n = 45) and IZ (n = 45) were fabricated and loaded in three-point bending (3P) in 37 • C artificial saliva (IA 3P and IZ 3P) and cyclic fatigued (F) in dry (D) and wet (W) conditions (IA FD , IA FW , IZ FD , IZ FW). The initial and the number of cycles to fracture were obtained from 3P and F tests, respectively. Data was examined using Weibull statistics. The SCG behavior was described in terms of crack velocity as a function of maximum stress intensity factor (K Imax). Results. The Weibull moduli (m = 8) were similar for both ceramics. The characteristic strength (0) of IA and IZ was and 466 MPa 550 MPa, respectively. The wet environment significantly increased the SCG of IZ, whereas a less evident effect was observed for IA. In general, both ceramics were prone to SCG, with crack propagation occurring at K I as low as 43-48% of their critical K I. The highest of IZ should lead to longer lifetimes for similar loading conditions. Significance. Water combined with cyclic loading causes pronounced SCG in IZ and IA materials. The lifetime of dental restorations based on these ceramics is expected to increase by reducing their direct exposure to wet conditions and/or by using high content zirconia ceramics with higher strength.

Research paper thumbnail of Work of adhesion of resin on treated lithia disilicate-based ceramic

Dental Materials, 2004

Objective. This study is to test the hypothesis that chemical etching and silane coating of a cer... more Objective. This study is to test the hypothesis that chemical etching and silane coating of a ceramic surface will influence the work of adhesion ðW A Þ of adhesive resin to dental ceramic. Methods. A hot-pressed lithia disilicate-based ceramic was used as a model material to investigate the influence of probing media and surface treatments on W A using a dynamic contact angle analyzer. Eighty ceramic specimens were randomly divided into eight experimental groups and treated as follows: (1 and 3) as polished; (2 and 4) etched with 9.5% hydrofluoric acid (HF) for 1 min; (5) etched with 4% acidulated phosphate fluoride (APF) for 2 min; (6) silane coated; (7) etched with HF for 1 min and silane coated; (8) etched with APF for 2 min and silane coated. Advancing and receding contact angles (u a and u r) were measured using high purity water (g ¼ 72:6 mN=m) for groups 1 and 2, and a liquid resin ðg ¼ 39:7 mN=mÞ for groups 3-8 as probing liquids. Results. The liquid resin medium yielded a lower W A than water. Silanization produced a significantly lower W A ðp , 0:001Þ than non-silanated surfaces. Etching alone consistently yielded a greater W A for all surface treatments ðp , 0:001Þ: Significance. The silanated ceramic surface exhibited a lower surface energy and did not enhance bonding to the liquid resin by work of adhesion.

Research paper thumbnail of Propriedades físicas dos fios de sutura usados na odontologia

Brazilian dental science, Aug 13, 2010

Objetivo: investigar as características físicas dos fios de sutura freqüentemente usados na odont... more Objetivo: investigar as características físicas dos fios de sutura freqüentemente usados na odontologia. Material e Método: Fios (n=10) de seda (FS) 4-0 e nylon (FN) 4-0 (Somerville Ltda.) foram testados de acordo com a norma NBR 13904:2003. O comprimento foi determinado com escala rígida, sem tensionar o fio. O diâmetro foi avaliado utilizando um metroscópio e um relógio comparador digital. As cargas de ruptura em tração sobre nó (L no) e ao encastoamento (L f) foram testados em uma máquina de ensaio universal com velocidade de 1mm/min. Os resultados foram analisados estatisticamente pelo teste t de Student (α = 0,05). Resultados: Todos os fios cumpriram com as especificações quanto ao comprimento. Os FN apresentaram um valor médio de diâmetro de 0,17 mm, contudo os FS apresentaram um valor médio de 0,21 mm, ficando fora da faixa específica (0,15-0,199 mm). Valores médios de L no foram significativamente maiores para os FS (7,54 ± 0,50 N) do que para os FN (6,67 ± 0,83 N) (p<0,05). Todos os fios resistiram ao teste de encastoamento com valores acima dos limites individual e médio mínimos preconizados, respectivamente 2,26 N e 4,41 N, sendo que os valores médios de FS (8,98 ± 2,16 N) foram significativamente maiores do que os FN (7,27 ± 1,31 N) (p<0,05). Conclusão: Essas diferenças podem ter sido induzidas pelo maior diâmetro dos FS, pois assumindo os valores médios de diâmetro e carga obtem-se valores de resistência a tração sobre nó (σ no) de 203,

Research paper thumbnail of Evidências ciEntíficas para a adEsão dE bráquEtEs cErâmicos a difErEntEs substratos odontológicos Scientific evidences for bonding of ceramic brackets to different dental substrates

Evidências ciEntíficas para a adEsão dE bráquEtEs cErâmicos a difErEntEs substratos odontológicos Scientific evidences for bonding of ceramic brackets to different dental substrates

Evidências cien-tíficas para a adesão de bráquetes cerâmicos a diferentes substratos odontológico... more Evidências cien-tíficas para a adesão de bráquetes cerâmicos a diferentes substratos odontológicos. SALUSVITA, Bauru, v. 33, n. 3, p. 365-387, 2014. rEsumo Introdução: Existe uma grande demanda por tratamento ortodôntico em pacientes adultos, que requerem frequentemente uma adequada adesão de bráquetes a vários substratos, além do esmalte dental, tais como: porcelanas, ligas metálicas, amálgama, ouro, dentina, resinas compostas e acrílicas. Objetivo: Apresentar revisão da literatura so-bre os mecanismos adesivos empregados para a adesão de bráquetes cerâmicos aos diversos substratos encontrados na clínica odontoló-gica e as propriedades dos bráquetes cerâmicos, sugerindo proto-colos adesivos com base em evidências. Métodos: A pesquisa foi realizada na base de dados PubMed, em artigos publicados a partir de 1986, incluindo aos temas: bráquetes cerâmicos e resistência de união em ortodontia. Resultados: A estética e a biocompatibilidade foram reportadas como as maiores vantagens dos b...

Research paper thumbnail of Effect of ceramic surface treatment on tensile bond strength to a resin cement

Effect of ceramic surface treatment on tensile bond strength to a resin cement

The International journal of prosthodontics

The objective of this study was to test the following hypotheses: (1) hydrofluoric acid (HF)-trea... more The objective of this study was to test the following hypotheses: (1) hydrofluoric acid (HF)-treated ceramic surfaces produce the highest tensile bond strength to resin cements, independent of the ceramic microstructure and composition; and (2) the tensile bond strength test is appropriate for analysis of interfacial adhesion for ceramic-bonded-to-resin systems. Ceramic specimens were polished with 1-micron alumina abrasive and divided into four groups of 10 specimens for each of seven ceramic types. One of the following surface treatments was applied: (1) 10% ammonium bifluoride (ABF) for 1 minute; (2) 9.6% HF for 2 minutes; (3) 4% acidulated phosphate fluoride (APF) for 2 minutes; and (4) a silane coupling agent. The surface-treated areas were coated with an adhesive resin and bonded to a resin cement. Specimens were loaded to failure in tension using a testing machine. Tensile bond strength data were statistically analyzed, and fracture surfaces were examined to determine the mod...

Research paper thumbnail of Modes of Failure of Bonding Interfaces in Dentistry

Modes of Failure of Bonding Interfaces in Dentistry

Ceramic Transactions, 2012

Research paper thumbnail of Influence of ceramic pre-treatments on tensile bond strength and mode of failure of resin bonded to ceramics

Influence of ceramic pre-treatments on tensile bond strength and mode of failure of resin bonded to ceramics

American journal of dentistry, 2007

To evaluate the effect of ceramic surface treatments on tensile bond strength (sigma) and the mod... more To evaluate the effect of ceramic surface treatments on tensile bond strength (sigma) and the mode of failure of a resin bonded to a feldspathic glass and a low-crystalline ceramic, testing the hypothesis that a silica coating treatment is unnecessary for both the glass and the low-crystalline ceramic. 10 blocks of each the feldspathic glass (V7-VITAVM7) and the leucite-based ceramic (E1-IPS Empress) were fabricated and polished. Five blocks of each ceramic were treated as follows: 9.5% hydrofluoric acid for 60 seconds; and silica coating using Cojet System for 15 seconds. After silane coating, an adhesive resin and a composite were applied and polymerized. The composite-ceramic blocks were cut to produce bar-shaped specimens (n = 30) that were stored in distilled water at 37 degrees C for 7 days before tensile loading to failure in a universal testing machine. Data were statistically analyzed using analysis of variance, Tukey's test (alpha = .01) and Weibull analysis. Fracture ...

Research paper thumbnail of Contributions of stress corrosion and cyclic fatigue to subcritical crack growth in a dental glass-ceramic

Dental Materials, 2014

Objective-The objective of this study was to test the following hypotheses: 1. Both cyclic degrad... more Objective-The objective of this study was to test the following hypotheses: 1. Both cyclic degradation and stress-corrosion mechanisms result in subcritical crack growth (SCG) in a fluorapatite glass-ceramic (IPS e.max ZirPress, Ivoclar-Vivadent). 2. There is an interactive effect of stress corrosion and cyclic fatigue to accelerate subcritical crack growth. Methods-Rectangular beam specimens were fabricated using the lost-wax process. Two groups of specimens (N=30/group) with polished (15 µm) or air-abraded surface were tested under rapid monotonic loading. Additional polished specimens were subjected to cyclic loading at two frequencies, 2 Hz (N=44) and 10 Hz (N=36), and at various stress amplitudes. All tests were performed using a fully articulated four-point flexure fixture in deionized water at 37°C. The SCG parameters were determined using the ratio of inert strength Weibull modulus to lifetime Weibull modulus. A general log-linear model was fit to the fatigue lifetime data including time to failure, frequency, peak stress, and the product of frequency and logarithm of stress in ALTA PRO software. Results-SCG parameters determined were n=21.7 and A=4.99×10−5 for 2 Hz, and n=19.1 and A=7.39×10−6 for 10 Hz. After fitting the general log-linear model to cyclic fatigue data, the coefficients of the frequency term (α1), the stress term (α2), and the interaction term (α3) had estimates and 95% confidence intervals of α1= −3.16 (−15.1, 6.30), α2= −21.2 (−34.9, −9.73), and α3= 0.820 (−1.59, 4.02). Only α2 was significantly different from zero.

Research paper thumbnail of Atendimento odontológico de pacientes surdo-cegos: enfrentando desafios

Revista da Faculdade de Odontologia - UPF, 2013

Research paper thumbnail of Efficacy and Safety of 10% and 16% Carbamide Peroxide Tooth-whitening Gels: A Randomized Clinical Trial

Operative Dentistry, 2008

Clinical Relevance This clinical trial suggests that two carbamide peroxide concentrations, when ... more Clinical Relevance This clinical trial suggests that two carbamide peroxide concentrations, when used once a day for three weeks, were well tolerated by patients and were effective in tooth whitening. Although some tooth sensitivity occurred during treatment, this side effect was mostly mild and transient.

Research paper thumbnail of The effect of ceramic surface treatment on bonding to densely sintered alumina ceramic

The effect of ceramic surface treatment on bonding to densely sintered alumina ceramic

The Journal of Prosthetic Dentistry, 2005

Ceramic surface treatment is crucial for bonding to resin. High crystalline ceramics are poorly c... more Ceramic surface treatment is crucial for bonding to resin. High crystalline ceramics are poorly conditioned using traditional procedures. The purpose of this study was to evaluate the effect of silica coating on a densely sintered alumina ceramic relative to its bond strength to composite, using a resin luting agent. Material and methods Blocks (6 x 6 x 5 mm) of ceramic and composite were made. The ceramic (Procera AllCeram) surfaces were polished, and the blocks were divided into 3 groups (n = 5): SB, airborne-particle abrasion with 110-microm Al 2 O 3 ; RS, silica coating using Rocatec System; and CS, silica coating using CoJet System. The treated ceramic blocks were luted to the composite (W3D Master) blocks using a resin luting agent (Panavia F). Specimens were stored in distilled water at 37 degrees C for 7 days and then cut in 2 axes, x and y, to obtain specimens with a bonding area of approximately 0.6 mm 2 (n = 30). The specimens were loaded to failure in tension in a universal testing machine, and data were statistically analyzed using a randomized complete block design analysis of variance and Tukey&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s test (alpha=.05). Fractured surfaces were examined using light microscopy and scanning electron microscopy to determine the type of failure. Energy-dispersive spectroscopy was used for surface compositional analysis. Mean bond strength values (MPa) of Groups RS (17.1 +/- 3.9) ( P =.00015) and CS (18.5 +/- 4.7) ( P =.00012) were significantly higher than the values of Group SB (12.7 +/- 2.6). There was no statistical difference between Groups RS and CS. All failures occurred at the adhesive zone. Tribochemical silica coating systems increased the tensile bond strength values between Panavia F and Procera AllCeram ceramic.

Research paper thumbnail of Removal of partially or fully polymerized resin from porcelain veneers

Removal of partially or fully polymerized resin from porcelain veneers

The Journal of Prosthetic Dentistry, 1993

Research paper thumbnail of A Variety of Patient Factors may Influence Porcelain Veneer Survival Over a 10-Year Period

A Variety of Patient Factors may Influence Porcelain Veneer Survival Over a 10-Year Period

Journal of Evidence Based Dental Practice, 2010

Clinical records were reviewed for more than 80,000 different patients from the General Dental Se... more Clinical records were reviewed for more than 80,000 different patients from the General Dental Services (GDS) in England and Wales. A total of 2562 porcelain veneer restorations were placed in 1177 adult patients (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or =18 years old, 35% male and 65% female) over a period of 11 years (January, 1991, to March, 2002). A number of factors were considered potentially capable of impacting the need for reintervention on teeth restored with porcelain veneers. These included a number of patient factors such as gender, age, and dental utilization practices. Other factors analyzed included the tooth position receiving veneers, dentists&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; qualifications, and where and when the veneer was placed (eg, month and geographic location). The main outcome was survival over 10 years between initial placement and the first date of intervention for each tooth treated with a porcelain veneer. Information was abstracted from clinical records to create an analytical dataset of porcelain veneers, with their dates of placement and their dates, if any, of reintervention. This dataset was analyzed using a modified Kaplan-Meier statistic and a Cox-regression model. Factors that were found to influence the survival of porcelain veneers included the following: gender, with veneers placed in male patients surviving for less time than those placed for female patients (P = .01); patient age, with poorer survival of porcelain veneers in older (60 years or older) patients (P = .003); changing dentist, with teeth of patients who change dentist surviving for shorter periods of time to reintervention than for those patients who continue in the care of the same dentist (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001); patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s treatment need, with patients whose gross annual fees on all dental treatment are higher having teeth with less time to reintervention after receiving veneers than those patients with lower annual fees (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001); patient paying status, with patients who are exempt from charges also having veneered teeth with shorter time to reintervention (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.001). Nevertheless, the factors associated with tooth position or mouth quadrant and with the dentist (gender, age, years since graduation, and country of qualification) did not influence the survival rate. Although dentist factors do not appear to play a part, a variety of patient factors have been found to influence veneer survival to reintervention.…

Research paper thumbnail of Effect of endodontic sealers on tooth color

Journal of Dentistry, 2013

Research paper thumbnail of Effect of acid etching of glass ionomer cement surface on the microleakage of sandwich restorations

Journal of Applied Oral Science, 2007

he purposes of this study were to evaluate the sealing ability of different glass ionomer cements... more he purposes of this study were to evaluate the sealing ability of different glass ionomer cements (GICs) used for sandwich restorations and to assess the effect of acid etching of GIC on microleakage at GIC-resin composite interface. Forty cavities were prepared on the proximal surfaces of 20 permanent human premolars (2 cavities per tooth), assigned to 4 groups (n=10) and restored as follows: Group CIE-conventional GIC (CI) was applied onto the axial and cervical cavity walls, allowed setting for 5 min and acid etched (E) along the cavity margins with 35% phosphoric acid for 15 s, washed for 30 s and water was blotted; the adhesive system was applied and light cured for 10 s, completing the restoration with composite resin light cured for 40 s; Group CIN-same as Group CIE, except for acid etching of the CI surface; Group RME-same as CIE, but using a resin modified GIC (RMGIC); Group RMN-same as Group RME, except for acid etching of the RMGIC surface. Specimens were soaked in 1% methylene blue dye solution at 24ºC for 24 h, rinsed under running water for 1 h, bisected longitudinally and dye penetration was measured following the ISO/TS 11405-2003 standard. Results were statistically analyzed by Kruskal-Wallis and chi-square tests (α=0.05). Dye penetration scores were as follow: CIE-2.5; CIN-2.5; RME-0.9; and RMN-0.6. The results suggest that phosphoric acid etching of GIC prior to the placement of composite resin does not improve the sealing ability of sandwich restorations. The RMGIC was more effective in preventing dye penetration at the GIC-resin compositedentin interfaces than CI.

Research paper thumbnail of Radiographic evaluation of furcal perforations sealed with different materials in dogs' teeth

Journal of Applied Oral Science, 2011

The objective of this work was to evaluate, using radiographic images, the behavior of four mater... more The objective of this work was to evaluate, using radiographic images, the behavior of four materials used to repair root perforations in dogs' teeth. Material and Methods: Second and third premolars of 6 dogs were used. The 48 teeth were randomly divided into 4 groups (n=12) and the perforations were sealed with one of the following materials: MTA, AH Plus, Vitremer and gutta-percha. Dogs were submitted to general anesthesia, teeth were radiographed and pulp was accessed. Perforations were done, at WKH PD[LPXP FXUYH RI WKH SXOS ÀRRU VHDOHG DQG WKH DFFHVVHG FRURQDO FDYLW\ ZDV ¿OOHG ZLWK JODVV LRQRPHU FHPHQW 9LGULRQ 5 $IWHU GD\V WKH GRJV ZHUH VDFUL¿FHG DQG WKH last x-ray image was taken. Images were analyzed for the presence/absence of periodontal lesions at the perforation region. Data were analyzed statistically by chi-square test at VLJQL¿FDQFH OHYHO 5HVXOWV 7KHUH ZHUH QR VWDWLVWLFDOO\ VLJQL¿FDQW GLIIHUHQFHV S among AH Plus, Vitremer and gutta-percha groups. MTA produced the smallest number of periodontal lesions (p<0.05). Conclusions: It may be concluded that none of the tested materials was able to preserve the integrity of the periodontal tissues in the furcation region, and the use of MTA resulted in the least formation of adjacent periodontal bone lesions revealed by the radiographic comparisons.

Research paper thumbnail of Characterizing ceramics and the interfacial adhesion to resin: II- the relationship of surface treatment, bond strength, interfacial toughness and fractography

Journal of Applied Oral Science, 2005

The clinical success of resin bonding procedures for indirect ceramic restorations and ceramic re... more The clinical success of resin bonding procedures for indirect ceramic restorations and ceramic repairs depends on the quality and durability of the bond between the ceramic and the resin. The quality of this bond will depend upon the bonding mechanisms that are controlled in part by the surface treatment that promote micromechanical and/or chemical bonding to the substrate. The objective of this review is to correlate interfacial toughness (K A) with fracture surface morphological parameters of the dental ceramic-resin systems as a function of ceramic surface treatment. This analysis is designed to identify mechanisms that promote adhesion of these ceramic-resin systems and an appropriate bond test method to yield relevant adhesion performance data.

Research paper thumbnail of Microbial leakage and apical inflammatory response in dog's teeth after root canal filling with different sealers, post space preparation and exposure to the oral environment

Journal of Applied Oral Science, 2007

oronal leakage is an important factor affecting the outcome of endodontic therapy. This study eva... more oronal leakage is an important factor affecting the outcome of endodontic therapy. This study evaluated the microbial leakage (ML) and the apical inflammatory response (AIR) in dog's teeth after root canal filling with three endodontic sealers, post preparation and exposure to the oral environment, testing the hypothesis that there is a positive correlation between these two histological parameters (ML and AIR). Sixty-four root canals of 8 mongrel dogs were cleaned, shaped and randomly distributed into groups according to the sealer to be used: Sealer 26 (n=18); AH Plus (n=18); RoekoSeal (n=19); no sealercontrol group (n=9). Root canals were filled by the lateral condensation technique. Post space preparation left 4 mm of filling material in the apical root third, and specimens were exposed to the oral environment for 90 days. The dogs were killed and jaw blocks were histologically processed using Brown & Brenn and HE staining techniques. ML and AIR were scored from 1 to 4. Results were analyzed statistically using ANOVA, Duncan's post-hoc test and Spearman's correlation. ML and AIR score means were: Sealer 26-2.44±0.98 and 2.50±0.70; AH Plus-2.50±0.78 and 2.22±0.54; RoekoSeal-1.84±0.95 and 2.63±0.83; Control-2.56±1.23 and 3.11±0.60. Statistically significant differences in AIR scores were found between the AH Plus and control groups (p<0.05). Although RoekoSeal had the lowest ML means, and AH Plus, the lowest AIR means after 90-day exposure to the oral environment, no statistically significant differences were found between the three sealers under study, and no correlation was found between ML and AIR.

Research paper thumbnail of Evaluation of Melia azedarach Extracts against American Bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

Entomologia Generalis, 2012

Melia azedarach (Linnaeus 1753) drupes and green leaves extracts (methanol and chloroform:methano... more Melia azedarach (Linnaeus 1753) drupes and green leaves extracts (methanol and chloroform:methanol) were evaluated against American bollworm, Helicoverpa armigera (Hubner 1806). Various concentrations of extracts were used to treat natural foods, viz leaves and pods/bolls of chickpea, pigeonpea, and cotton. Treated foods were offered to early stage (neonate) and advanced stage (grown up) larvae of H armigera for 48 h, and then, untreated food was offered for the rest of life. Chloroform:methanol (9:1) extracts of M azedarach drupes and leaves showed better insecticidal properties than methanol extracts. However, M azedarach drupes extract in chloroform:methanol (9:1) was the most promising in causing adverse morphogenic effect on various biological parameters of H armigera. Early stage larvae were more sensitive to the exposure of M azedarach extracts than advanced stage larvae.

Research paper thumbnail of Visual and instrumental agreement in dental shade selection: Three distinct observer populations and shade matching protocols

Dental Materials, 2009

Objectives. This study tested the hypothesis that the agreement between observer visual dental sh... more Objectives. This study tested the hypothesis that the agreement between observer visual dental shade matches and instrumental shade identification is higher using the Vita 3D-Master ® (3D) shade guide than the Vita classical (VC) shade guide. Methods. Three populations selected shade matches: non-dental observers (GP) matched shade tabs-to-tabs and dental students (DS) and dentists (DD) matched an in vivo natural right upper central incisor (RUCI). All observers (n = 600) used both shade guides (3D and VC) in two lighting conditions, cool white fluorescent lighting (CWF) and natural sunlight (NSL). The shade tabs and natural teeth were identified using an intra-oral spectrophotometer (Vita Easyshade TM) to determine the instrumental agreement with the visual shade selection. The percent visual-instrumental shade agreement (PVIA) was analyzed statistically considering: observer population, shade guide set, and lighting condition. Results. A "substantial" intra-examiner agreement (k = 0.76) was observed. The PVIA ranged from 12% (DS) for the 3D-NSL condition to 42% (DD) with the VC-CWF condition, which also resulted in the highest PVIA for GP (38.5%) and DS (35%). Results indicated that the GP with neither dental knowledge nor shade guide experience had a significantly higher PVIA using the VC rather than the 3D shade guide. Dentists demonstrated the highest PVIA (42%) for both lighting conditions and shade guides, thereby rejecting the study hypothesis. Significance. A significantly higher visual-instrumental shade agreement was demonstrated by the clinically experienced dentists (DD), regardless of shade guides and lighting conditions.

Research paper thumbnail of Mechanical strength and subcritical crack growth under wet cyclic loading of glass-infiltrated dental ceramics

Dental Materials, 2010

Objectives. Evaluate the flexural strength () and subcritical crack growth (SCG) under cyclic loa... more Objectives. Evaluate the flexural strength () and subcritical crack growth (SCG) under cyclic loading of glass-infiltrated alumina-based (IA, In-Ceram Alumina) and zirconia-reinforced (IZ, In-Ceram Zirconia) ceramics, testing the hypothesis that wet environment influences the SCG of both ceramics when submitted to cyclic loading. Methods. Bar-shaped specimens of IA (n = 45) and IZ (n = 45) were fabricated and loaded in three-point bending (3P) in 37 • C artificial saliva (IA 3P and IZ 3P) and cyclic fatigued (F) in dry (D) and wet (W) conditions (IA FD , IA FW , IZ FD , IZ FW). The initial and the number of cycles to fracture were obtained from 3P and F tests, respectively. Data was examined using Weibull statistics. The SCG behavior was described in terms of crack velocity as a function of maximum stress intensity factor (K Imax). Results. The Weibull moduli (m = 8) were similar for both ceramics. The characteristic strength (0) of IA and IZ was and 466 MPa 550 MPa, respectively. The wet environment significantly increased the SCG of IZ, whereas a less evident effect was observed for IA. In general, both ceramics were prone to SCG, with crack propagation occurring at K I as low as 43-48% of their critical K I. The highest of IZ should lead to longer lifetimes for similar loading conditions. Significance. Water combined with cyclic loading causes pronounced SCG in IZ and IA materials. The lifetime of dental restorations based on these ceramics is expected to increase by reducing their direct exposure to wet conditions and/or by using high content zirconia ceramics with higher strength.

Research paper thumbnail of Work of adhesion of resin on treated lithia disilicate-based ceramic

Dental Materials, 2004

Objective. This study is to test the hypothesis that chemical etching and silane coating of a cer... more Objective. This study is to test the hypothesis that chemical etching and silane coating of a ceramic surface will influence the work of adhesion ðW A Þ of adhesive resin to dental ceramic. Methods. A hot-pressed lithia disilicate-based ceramic was used as a model material to investigate the influence of probing media and surface treatments on W A using a dynamic contact angle analyzer. Eighty ceramic specimens were randomly divided into eight experimental groups and treated as follows: (1 and 3) as polished; (2 and 4) etched with 9.5% hydrofluoric acid (HF) for 1 min; (5) etched with 4% acidulated phosphate fluoride (APF) for 2 min; (6) silane coated; (7) etched with HF for 1 min and silane coated; (8) etched with APF for 2 min and silane coated. Advancing and receding contact angles (u a and u r) were measured using high purity water (g ¼ 72:6 mN=m) for groups 1 and 2, and a liquid resin ðg ¼ 39:7 mN=mÞ for groups 3-8 as probing liquids. Results. The liquid resin medium yielded a lower W A than water. Silanization produced a significantly lower W A ðp , 0:001Þ than non-silanated surfaces. Etching alone consistently yielded a greater W A for all surface treatments ðp , 0:001Þ: Significance. The silanated ceramic surface exhibited a lower surface energy and did not enhance bonding to the liquid resin by work of adhesion.