In Vitro Evaluation Of The Abrasiveness Of A Commercial Low-abrasive Dentifrice And An Experimental Dentifrice Containing Vegetable Oil

Toothpastes usually contain detergents, humectants, water colorant, fluoride and thickeners (e.g. silica). Tooth wear has a multi-factorial etilology and the use of abrasive dentifrices is related to abrasion of dental tissues during toothbrushing. This study evaluated in vitro the abrasiveness of a commercial silica gel low-abrasive dentrifice compared to an experimental dentifrice containing vegetable (almond) oil. Distilled water served as a control group. Acrylic specimens (8 per group) were submitted to simulated toothbrushing with slurries of the commercial dentifrice experimental dentifrice, almond oil and water in an automatic brushing machine programmed to 30,000 brush strokes for each specimen which is equivalent to 2 years of manual toothbrushing. Thereafter, surface roughness (Ra) of the specimens was analyzed with a Surfcorder SE 1700 profilometer. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant differences (p>0.05) in the surface roughness after brushing with water almond oil experimental dentifrice. The commercial dentifrice produced rougher surfaces compared to the control and abrasive free products (p<0.05). Further studies are necessary in confirm the potential benefits of using vegetable oil in toothpaste as an alternative in abrasives in an attempt to minimize the tooth wear caused by toothbrushing.72415261530Löe, H., Kleinman, D.V., (1986) Dental Plaque Control Measures and Oral Hygiene Practices, , Oxford: IRL Press;, 332pBueno, M.A.M., Toledo, S., Sallum, E.A., Nociti Junior, F.H., Influência da escovação dental orientada na redução do sangramento gengival, em áreas próximas a restauraç-tioes metálicas. (1998) Rev ABO Nac, 6, pp. 44-47Andrade Junior, A.C.C., Andrade, M.R.T.C., Machado, W.A.S., Fischer, R.G., Abrasividade de dentifrícios: Revisão de literatura. (1997) Rev Periodontia, 6, pp. 25-30Baxter, P.M., Davis, W.B., Jackson, J., Toothpaste abrasive requirements to control naturally stained pellicle (1981) J Oral Rebabil, 8, pp. 19-26Hefferren, J.J., Schemehon, B., Storek, A., Lerck, M., Li, N., Silica as a reference for laboratory dentifrice assessment methods: Multiple collaborative study (2007) J Clin Dent, 8, pp. 12-16Stookey, G., Muhler, J., Laboratory studies concerning the enamel and dentin abrasion properties of common dentifrice polishing agents (1968) J Dent Res, 47, pp. 524-532Glantz, P.O., Larsson, L.A., Surface roughness of composite resins before and after toothbrushing (1972) Acta Odont Scand, 30, pp. 335-347Prampero, A.L., Lara, E.H.G., Tastes, R.C.A., Ogasawara, M.S., Panzeri, H., (1992) Relação das escovas com dentifrícios: Estudo da interação de escovas dentais de diferentes tipos de cerdas com preparações básicas para dentifr-acicios, 40, pp. 298-302. , RGOSlop, D., Rooij, J.F., Arends, J., Abrasion of enamel. 1. An in vitro investigation (1983) Caries Res, 17, pp. 242-248Heath, J., Wilson, J., Abrasion of restorative materials by toothpaste (1976) J Oral Rehabil, 3, pp. 121-138Patrão FGD, Sinhoreti MAC, Consani S, Correr Sobrinho L, Milan FM. Avaliação in vitro da rugosidade produzida por escovas dentais e dentifríicios em resina para base de prótese. Rev Fac Odontol Univ Passo Fundo. 19983: 7-14Correr Sobrinho, L., Francisco, M.U., Consani, S., Sinhoreti, M.A.C., Consani, R.L.X., Influência da escovação na rugosidade de superfície de materiais restauradores estéticos. (2001) PGR Pós-Grad Rev Fac Odontol São Jose dos Campos, 4, pp. 47-55Lara, E.H.G., Panzeri, H., Ogasawara, M.S., Ciampo, J.O.D., Moraes, J.T., Avaliação laboratorial dos dentifrícios cornerciais. (1996) Rev ABO Nac, 4, pp. 176-180Addy, M., Goodfield, S., Harrison, A., The use of acrylic to compare the abrasivity and stain removal proprieties of toothpastes (1991) Clin Mater, 7, pp. 219-225Addy, M., Evaluation of clinical trials of agents and procedures to prevent caries and periodontal disease: Choosing products and recommending procedures (1995) Int Dent J, 45, pp. 185-196Shaw, L., al-Dlaigan, Y.H., Smith, A., Childhood asthma and dental erosion (2000) J Dent Child, 67, pp. 102-106Al-Dlaigan, Y.H., Shaw, L., Smith, A.J., Is there a relationship between asthma and dental erosion? A case control study (2002) Int J Paediatric Dent, 12, pp. 189-200Aguiar, A.A.A., Moraes Filho, F.C., A interferência do óleo vegetal na aderência da placa bacteriana dental. (1998) Rev Cienc Odontol, 1, pp. 21-25Aguiar, A.A.A., Saliba, N.A., Toothbrushing with vegetable oil: A clinical and laboratorial analysis (2004) Braz Oral Res, 18, pp. 168-173Meneghim, M.C., Pereira, A.C., Silva, F.R.B., Prevalência da cárie radicular e condiç-tiao periodontal em uma população idosa institucionalizada de Piracicaba - SP. (2002) Pesqui Odontol Bras, 16, pp. 50-56Fransson, C., Berglundh, T., Lindhe, J., The effect of age on the development of gingivitis. Clinical, microbiological and histological findings (1996) J Clin Periodontal, 23, pp. 379-385Lima FAP, Góes MF, Consani S. Avaliação in vitro da ação abrasiva de escovas dentais. Odonto. 1998;3:23-7Santos, P.H., (2000) Avaliação da porosidade interna e da rugosidade de superfície de resinas compostas para dentes posteriores submetidas à escovação, , Master's thesis, Piracicaba-SP: Piracicaba Dental School/UNICAMP;, 180pMoore, C., Addy, M., Wear of dentin in vitro by toothpaste abrasives and detergents alone and combined (2005) J Clin Periodontol, 32, pp. 1242-1246Joiner, A., Pickles, M.J., Tanner, C., Weader, E., Doyle, P., An in situ model to study the toothpaste abrasion of enamel (2004) J Clin Periodontol, 31, pp. 434-438Figueiredo, M.C., Bello, D., Avaliação comparativa entre a eficácia de uma escova alternativa e uma escova convencional na remoção de placa dent-acaria. (1999) Rev Fac Odontol Univ Passo Fundo, 4, pp. 13-2

Effect Of Refrigeration On Tensile Bond Strength Of Three Adhesive Systems.

The purpose of this study was to investigate the tensile bond strengths of three adhesive systems applied to dentin at refrigerated and room temperatures. Ninety bovine incisor teeth were obtained, embedded in self-cured acrylic resin, abraded on a lathe under water spray and polished to 400 and 600 grit to form standardized dentin surfaces before randomly assigning to six groups (n = 15). The adhesive systems Scotchbond Multi-Purpose, Single Bond and Prime & Bond NT were applied to dentin according to the manufacturers' instructions at refrigerated temperature (4 degrees C) and at room temperature (23 degrees C), before bonding resin-based composite (Z 100). The specimens were stored in distilled water at 37 degrees C for 24 hours and submitted to tensile bond strength tests on a universal testing machine (EMIC DL-2000) at a crosshead speed of 0.5 mm/min. The resulting data were statistically analyzed using analysis of variance and Tukey's test. No statistical differences were found when the adhesive systems were applied at refrigerated and room temperatures. Scotchbond Multi-Purpose and Single Bond had significantly stronger tensile bond strengths than Prime & Bond NT at room and refrigerated temperatures (p < 0.01). Scotchbond Multi-Purpose and Single Bond were statistically similar. No adverse effects upon tensile bond strength were observed when adhesive systems were taken directly from refrigerated storage.122757

Effect Of Monomer Content In The Monomer-polymer Ratio On Complete Denture Teeth Displacement

The purpose of the study was to verify the linear displacement of teeth in maxillary complete dentures influenced by different monomerpolymer ratios - according to the manufacturer's instructions, with 25% excess or 25% less monomer content - in the conventional and microwaved polymerization techniques. Wax base plates and wax planes were made on edentulous maxillary stone casts according to traditional method. The set was assembled in semi-adjustable articulator with a lower toothed stone cast as guide to mounting of the maxillary artificial teeth. Impressions were taken from this tooth arrangement with silicone and the mold was used to standardize the mounting of the teeth of all dentures. Referential points were made on the artificial teeth for linear measurements with optical microscope before processing of the dentures and after deflasking. Denture bases were conventionally packed with acrylic resin according to the monomer-polymer ratio protocol. Tooth displacement data were submitted to ANOVA and Tukey test (α=0.05). There were no statistically significant differences (p>0.05) between the group with monomer content recommended by the manufacturer and groups with 25% more and 25% less monomer, in both conventional and microwaved polymerizations. Excess or less monomer in the monomer-polymer ratio and polymerization types did not change the linear distance between teeth.223238244Consani, R.L.X., Domitti, S.S., Rizzatti-Barbosa, C.M., Consani, S., Effect of commercial types of acrylic resin on dimensional accuracy of denture base (2002) Braz Dent J, 13, pp. 57-60Paffenbarger, G.C., Woelfel, J.B., Sweeney, W.T., Resins and techniques used in constructing dentures (1965) Dent Clin N Am, 9, pp. 251-262Abuzar, M.A.M., Jamani, K., Abuzar, M., Tooth movement during processing of complete dentures and its relation to palatal from (1995) J Prosthet Dent, 73, pp. 445-449Chen, J.C., Lacefield, W.R., Castleberry, D.J., Effect of denture thickness and curing cycle on the dimensional stability of acrylic resin denture bases (1988) Dent Mater, 4, pp. 20-24Perlowski, S.A., Investment changes during flasking as a factor of complete denture malocclusion (1953) J Prosthet Dent, 3, pp. 497-499Anusavice, K.J., (2003) Phillips' Science of Dental Materials, , 11th. ed. Elsevier, ChicagoReeson, M.G., Jepson, N.J.A., Achieving an even thickness in heatpolymerized permanent acrylic resin denture bases for complete dentures (1999) J Prosthet Dent, 82, pp. 359-361Consani, R.L.X., Domitti, S.S., Consani, S., Effect of a new tension system, used in acrylic resin flasking, on the dimensional stability of denture bases (2002) J Prosthet Dent, 88, pp. 285-289Cardash, H.S., Applebaum, B., Baharay, H., Liberman, R., Effect of retention grooves on tooth-denture base bond (1990) J Prosthet Dent, 64, pp. 492-496Consani, R.L.X., Domitti, S.S., Consani, S., Tanji, M., Effect of benchdelay after flask cooling on the posterior teeth movement in maxillary complete dentures (2003) Braz Dent Sci, 6, pp. 6-10Boscato, N., Consani, R.L.X., Consani, S., Cury, A.A.D.B., Effect of investment material and water immersion time on tooth movement in complete denture (2005) Eur J Prosthodont Rest Dent, 13, pp. 164-169Shibayama, R., Gennari, F.H., Mazaro, J.V., Vedovatto, E., Assunção, W.G., Effect of flasking and polimerization techniques on tooth movement in complete denture processing (2009) J Prosthodont, 18, pp. 259-264Keenan, P.L.J., Radford, D.R., Clark, R.K.F., Dimensional change in complete dentures fabricated by injection molding and microwave processing (2003) J Prosthet Dent, 89, pp. 37-44Negreiros, W.A., Consani, R.L.X., Mesquita, M.F., Consani, S., Valentino, T.A., Effect of the flask contention method on the displacement of maxillary denture teeth (2008) Braz J Oral Sci, 7, pp. 1493-1496Negreiros, W.A., Consani, R.L.X., Mesquita, M.F., Sinhoreti, M.A.C., Faria, I.R., Effect of the flask closure method and post-pressing time on the displacement of maxillary denture teeth (2009) Open Dent J, 3, pp. 21-25Consani, R.L.X., Domitti, S.S., Mesquita, M.F., Consani, S., Effect of packing types on the dimensional accuracy of denture base resin cured by the convencional cycle in relation to post-pressing times (2004) Braz Dent J, 5, pp. 63-67Vallittu, P.K., Ruyter, I.E., Buykuilmaz, S., Effect of polymerization temperature and time on the residual monomer content of denture base polymers (1998) Eur J Oral Sci, 106, pp. 588-593Bayraktar, G., Guvener, B., Bural, C., Uresin, Y., Influence of polymerization method, curing process, and length of time of storage in water on the residual methyl methacrylate content in dental acrylic resins (2006) J Biomed Mater Res B Appl Biomater, 76, pp. 40-345Lung, C.Y., Darvell, B.W., Minimization of the inevitable residual monomer in denture base acrylic (2005) Dent Mater, 21, pp. 1119-1128Zissis, A., Yannikakis, S., Polyzois, G., Harrison, A., A long term study on residual monomer release from denture materials (2008) Eur J Prosthodont Rest Dent, 16, pp. 81-8

Palaeoenvironmental analysis of the Miocene barnacle facies: case studies from Europe and South America

Acorn barnacles are sessile crustaceans common in shallow-water settings, both in modern oceans and in the Miocene geological record. Barnacle-rich facies occur from polar to equatorial latitudes, generally associated with shallow-water, high-energy, hard substrates. The aim of this work is to investigate this type of facies by analysing, from the palaeontological, sedimentological and petrographical points of view, early Miocene examples from Northern Italy, Southern France and South-western Peru. Our results are then compared with the existing information on both modern and fossil barnacle-rich deposits. The studied facies can be divided into two groups. The first one consists of very shallow, nearshore assemblages where barnacles are associated with an abundant hard-substrate biota (e.g., barnamol). The second one includes a barnacle-coralline algae association, here named “barnalgal” (= barnacle / red algal dominated), related to a deeper setting. The same pattern occurs in the distribution of both fossil and recent barnacle facies. The majority of them are related to very shallow, high-energy, hard-substrate, a setting that represents the environmental optimum for the development of barnacle facies, but exceptions do occur. These atypical facies can be identified through a complete analysis of both the skeletal assemblage and the barnacle association, showing that barnacle palaeontology can be a powerful tool for palaeoenvironmental reconstruction

Influence of casting methods on marginal and internal discrepancies of complete cast crowns.

The relationship between the application of die-spacer prior to wax pattern fabrication and metal removal from the inner surface of the casting on marginal and internal discrepancies of complete cast crowns was evaluated. One hundred and twenty complete crowns were cast with palladium-silver alloy melted by gas-oxygen torch or electrical resistance and cast with a centrifuge casting machine. After casting, the crowns were seated on each type of different marginal configuration dies (90-degree shoulder, 20-degree beveled shoulder, and 45-degree chamfered shoulder) with a static load of 90 N during 1 min. Evaluation of the marginal fit of the specimens was made using a digital micrometer. The crowns were embedded in acrylic resin and longitudinally sectioned to verify the internal discrepancy that occurred in lateral and occlusal interfaces with a digital micrometer. The data were submitted to ANOVA and Tukey's test with a significance level of 5%. The best marginal and inner fits were obtained with the gas-oxygen torch source. The 45-degree chamfered shoulder showed the best marginal and inner fit, and better internal relief was obtained in the crowns abraded with 50 microm Al2O3 particles

Disentangling thermal and nonthermal excited states in a charge-transfer insulator by time- and frequency-resolved pump-probe spectroscopy

Time- and frequency-resolved pump-probe optical spectroscopy is used to investigate the effects of the impulsive injection of delocalized excitations through a charge-transfer process in insulating CuGeO3. A large broadening of the charge-transfer edge is observed on the sub-ps time scale. The modification of this spectral feature cannot be attributed to the local increase in the effective temperature, as a consequence of the energy absorbed by the pump pulse. The measured modifications of the optical properties of the system are consistent with the creation of a nonthermal state, metastable on the picosecond time scale, after the pump-induced impulsive modification of the electron interactions

Shear bond strength of metallic orthodontic brackets bonded to enamel prepared with self-etching primer

The aim of this study was to determine the shear bond strength of different composites and to determine the adhesive remnant index (ARI) of metallic brackets bonded to enamel prepared with Transbond Plus Self-Etching Primer (TPSEP). Forty human premolars were divided into four equal groups. In group 1 (control), the Transbond XT was conventionally used. In groups 2-4, the TPSEP was used before bonding with Transbond XT, Z-100, and Concise Orthodontic, respectively. After the bonding, the samples were stored in distilled water at 37 degrees C for 24 hours. The brackets were debonded using a universal testing machine at a crosshead speed of 0.5 mm/ min. The shear bond strength (MPa) for group 1 (control), group 2 JPSEP + Transbond XT), group 3 JPSEP + Z-100), and group 4 JPSEP + Concise Orthodontic) were of 6.43, 4.61, 4.74, and 0.02, respectively. Group 1 was statistically superior to other groups (P .05), although both were statistically superior to group 4 (P < .05). According to the ARI evaluation, most of the failures involved the bracket/composite interface (groups 1 and 2) as well as the enamel/composite interface (groups 3 and 4). The Transbond XT conventionally bonded showed better adhesion results than Transbond XT, Z-100, and Concise Orthodontic after using Transbond Plus Self-Etching Primer.75584985

An Alternative Method for Thermal Cycling Test: Effect on the Marginal Microleakage and Bond Strength of Dental Polymer Bonded to Dentin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This study evaluated an alternative method for thermal cycling test on the microleakage and bond strength of the polymer-dentin bond. For the microleakage test the cavities were restored with a TEGDMA+UDMA+bis-EMA composite polymer light cured for 20 s. Samples were immersed in 2% methylene blue solution for 2 h and sectioned. Microleakage scores were submitted to Kruskal-Wallis test. For the shear bond strength test the adhesive was applied to dentin, photoactivated for 10 s and the composite polymer incrementally photoactivated. Samples were submitted to shear bond strength test in a machine with a cross-head speed of 0.5 mm/min and data were submitted to ANOVA and Tukey's test. Studied groups were: 1 - without thermocycling; 2 - thermocycled at 5 degrees C and 55 degrees C with intermediate bath at 37 degrees C; 3 - thermocycled at 5 degrees C and 37 degrees C; 4 - thermocycled at 37 degrees C and 55 degrees C; 5 - thermocycled at 5 degrees C and 55 degrees C (traditional test). Cold baths promoted greater microleakage when compared to control and hot bath, whereas control and hot bath were similar. Cold baths presented significant lower shear bond strength than those submitted to hot bath and control. It was concluded that the alternative method for thermal cycling test showed that cold temperatures increased the microleakage and decreased the bond strength of the polymeric adhesive.15610451049Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Palaeoenvironmental analysis of the Miocene barnacle facies: Case studies from Europe and South America

Acorn barnacles are sessile crustaceans common in shallow-water settings, both in modern oceans and in the Miocene geological record. Barnacle-rich facies occur from polar to equatorial latitudes, generally associated with shallow-water, high-energy, hard substrates. The aim of this work is to investigate this type of facies by analysing, from the palaeontological, sedimentological and petrographical points of view, early Miocene examples from Northern Italy, Southern France and South-western Peru. Our results are then compared with the existing information on both modern and fossil barnacle-rich deposits. The studied facies can be divided into two groups. The first one consists of very shallow, nearshore assemblages where barnacles are associated with an abundant hard-substrate biota (e.g., barnamol). The second one includes a barnacle-coralline algae association, here named &quot;barnalgal&quot; (=barnacle/red algal dominated), related to a deeper setting. The same pattern occurs in the distribution of both fossil and recent barnacle facies. The majority of them are related to very shallow, high-energy, hard-substrate, a setting that represents the environmental optimum for the development of barnacle facies, but exceptions do occur. These atypical facies can be identified through a complete analysis of both the skeletal assemblage and the barnacle association, showing that barnacle palaeontology can be a powerful tool for palaeoenvironmental reconstruction