Mariana de Souza AraÚjo Wasilewski, dds, mds, Marcos Kenzo Takahashi, dds, mds, phd,
Giovanna Andraus Kirsten, dds, mds & Evelise Machado de Souza, dds, mds, phd
Abstract: Purpose: To evaluate the effect of cigarette smoke and whiskey on the color stability of resin composites. Methods: Disk-shaped specimens (8 mm x 1 mm) were prepared with five composites in two different shades (n=10). After light-curing, the specimens were stored in dark containers with artificial saliva at 37ºC for 24 hours. Baseline color was measured by CIEL*a*b* using a colorimeter (Easy-Shade, VITA). Half of the specimens were subjected to a discoloration process in a cigarette smoking machine (SM) and the other half to an immersion in whiskey (WH) for 24 hours. Another color measurement was performed for discolored specimens. The samples subjected to smoking were immersed in whiskey (SM/WH) and those subjected to whiskey immersion were subjected to cigarette smoking (WH/SM) followed by another color measurement. Color changes (∆E*) were calculated and submitted to repeated measures 4-way ANOVA and Tukey tests (P< 0.05). Results: The most significant color change was observed after WH/SM (∆E*= 22.8-31.5) discoloration process, followed by SM (∆E*= 7.0-18.0), SM/WH (∆E*= 4.9-16.5) and WH (∆E*= 2.0 to 9.5). Translucent shades were more susceptible to discoloration than enamel shades. All the groups, with the exception of two, showed a significantly high perceptible color change (∆E*> 3.3). Based on the results, the color stability of dental composites was affected by the discoloration process and was material and shade dependent. (Am J Dent 2010;23:4-8).
Address: Dr. Evelise Machado de Souza,
School of Dentistry, Post-graduate Program, Pontifical Catholic University of
Parana, R. Imaculada Conçeicão, 1155, Prado Velho Curitiba, PR, 80215-901,
Yiming Li, dds, msd, phd, Sean Lee, dds, Philippe Hujoel, dmd, phd, Mingfang Su, dds, ms, Wu Zhang, md, Jay Kim, phd, Yun Po Zhang, ms, phd & William DeVizio, dmd
Abstract: Purpose: To investigate prevalence and severity of gingivitis in representative American adults. Methods: Subjects (1,000) in Loma Linda, California; Seattle, Washington; and Boston, Massachusetts were examined for Löe-Silness Gingivitis Index (GI). Mann-Whitney rank sum test was used to determine significances in the GI between genders. The data among study sites and races were compared using the Kruskal-Wallis one-way ANOVA on ranks. The correlation of the GI and age was examined by the Spearman rank order correlation. Age differences among three sites were analyzed using the one-way ANOVA. Results: The race composition of the subjects (mean age 37.9) approximated to the 2004 U.S. Census data. The overall average GI was 1.055. Only 6.1% of subjects showed mean GI <0.50; most (93.9%) were ≥ 0.50, with 55.7% ≥ 1.00. There was a significant correlation (P< 0.001) between the age and GI. The males’ GI was significantly higher (P< 0.001) than the females’; African-Americans showed a significantly higher GI (P< 0.05) than other races except for the Native-Americans. (Am J Dent 2010;23:9-13).
Address: Dr. Yiming Li, Center for Dental Research, Loma Linda University School of Dentistry, 24876 Taylor Street, Loma Linda, CA 92350, USA. E-mail: email@example.com
Milena Cadenaro, dds, phd, Chiara Ottavia Navarra, dds, phd, Francesca Antoniolli, eng, phd,
Annalisa Mazzoni, dds, phd, Roberto Di Lenarda, dds, Frederick Allen Rueggeberg, dmd, ms
& Lorenzo Breschi, dds, phd
Abstract: Purpose: To compare the effect of curing mode (self- or light-cure) on the extent of polymerization (%EPl as measured using differential scanning calorimetry, (DSC) and microhardness of two dual-cured, self-adhesive resin cements, using a conventional, dual-cured resin cement as control. Methods: Small amounts of the commercial self-adhesive cements Maxcem and RelyX Unicem or Panavia F2.0 dual-cure resin based cement used as control were polymerized within the DSC chamber at 35°C under a nitrogen atmosphere. 10 specimens were light-cured immediately (20 seconds, 600 mW/cm2) and left undisturbed for 2 hours and 10 additional specimens were left to self-cure in the dark for 2 hours. Following DSC treatment, microhardness of the specimens was measured (Vickers). For each test parameter, data were analyzed with a two-way ANOVA and the Tukey post hoc test. Results: %EP and microhardness of all cements were higher when the light-cure mode of dual-activation was used (P< 0.05) instead of only self-curing. No significant difference in %EP was found between either self-adhesive cement or the control using either the light- or self-curing modes. In the light-activated mode, the conventional, dual-cure control cement demonstrated lower microhardness than the self-adhesive cements (P< 0.05). (Am J Dent 2010;23:14-18).
Address: Prof. Lorenzo Breschi, Department of Biomedicine, Unit of Dental Sciences and Biomaterials, University of Trieste, Piazza Ospedale 1, I-34129 Trieste, Italy. E-mail: firstname.lastname@example.org
Yong Hoon Kwon, phd, Dong-Hee Shin, dds, ms, Dong-In Yun, dds, ms, Young-Joon Heo, dds,
Hyo-Joung Seol, phd & Hyung-Il Kim, dds, phd
Abstract: Purpose: To examine the effect of hydrogen peroxide on the microhardness and color change of resin composites containing nanofillers. Methods: Three resin nanocomposites with three different shades and two different tooth whitening agents were used. The specimens were given a 3-week treatment with one of three protocols: (1) 7 hours/day treatment of carbamide peroxide (CP) + 17 hours/day immersion in distilled water (DW); (2) 1 hour/week treatment of hydrogen peroxide (HP) + immersion in DW for the rest of the week; and (3) immersion in DW for 24 hours/day. The microhardness and color changes were measured after treatment. Results: After treatment with the whitening agents, there was an 8.1~10.7% decrease in the original microhardness. These values were similar to those obtained from the samples treated with distilled water. In the same resin product, the decrease was similar regardless of the test agents used. In most cases, the color change was only slight (ΔE*=0.5~1.4). Hydrogen peroxide enhanced the color change but the absolute color change values were similar in the same product and shade, regardless of the test agent used. (Am J Dent 2010;23:19-22).
Address: Prof. Yong Hoon Kwon, Department of Dental Materials, School of Dentistry, Pusan National University, Yangsan 626-870, Korea. E-mail: email@example.com
Renato JosÈ Gianini, dds, FlÁvia Lucisano Botelho do Amaral, dds, ms, FlÁvia MartÃo FlÓrio, dds, ms, scd & Roberta Tarkany Basting, dds, ms, phd
Abstract: Purpose: To evaluate the in vitro microtensile bond strength (µTBS) of etch-and-rinse and self-etch adhesive systems to demineralized dentin after the use of a papain-based chemomechanical method. Methods: 36 demineralized human dentin slabs were randomly distributed into two groups according to the method of caries removal: (1). Mechanical removal with manual excavators; (2) Chemomechanical removal with a papain-based gel (Papacárie). Subsequently, three adhesive systems were applied (n=6): (a) an etch-and-rinse adhesive system (Single Bond); (b) a two-step self-etch adhesive system (AdheSE); (c) a one-step self-etch adhesive system (Adper Prompt). The slabs were restored with a microhybrid resin composite and each resin-dentin block was sectioned into 1.0 mm2 thick slabs, which were kept in receptacles containing distilled water at relative humidity, for 24 hours, at 37°C. After that, they were subjected to tensile stress in a universal testing machine at a speed of 0.5 mm/minute. Data were submitted to two-way ANOVA and Tukey’s test at a 0.05 level of significance. The fractured specimens were observed under a stereomicroscope to assess the failure mode. Results: The application of both chemomechanical and mechanical methods on demineralized dentin yielded µTBS values that were statistically similar among them, regardless of the adhesive system used. Caries removal with a chemomechanical papain-based method did not interfere in the adhesion of the tested adhesive systems to demineralized dentin. (Am J Dent 2010;23:23-28).
Address: Prof. Dr. Roberta Tarkany Basting, Faculty of Dentistry and Center for Dental Research São Leopoldo Mandic, Department of Restorative Dentistry - Operative, Rua José Rocha Junqueira, 13 Bairro Swift, Campinas, SP, CEP: 13045-755, Brazil. E-mail: firstname.lastname@example.org
Ali I. Abdalla, phd
Abstract: Purpose: To evaluate the effect of water storage on the microtensile dentin bond strength of one total-etch and four self-etching adhesives to dentin. Methods: The adhesive materials were: one total-etch adhesive (Admira Bond) and four self-etch adhesives (Clearfil S tri Bond, Hybrid Bond, Futurabond NR, Adhe SE). Freshly extracted human third molar teeth were used. For each tooth, dentin was exposed on the occlusal surface by cutting with an Isomet saw and the remaining part was mounted in a plastic ring using dental stone. After adhesive application, a composite resin (Grandio) was placed in 5-6 mm height to form a crown segment. For each tested adhesive, two test procedures (n=6 teeth) were carried out. Procedure A: the teeth were stored in water for 24 hours, and then sectioned longitudinally, buccolingually and mesiodistally to get rectangular beams of 1 ± 0.1 mm thickness on which a micro-tensile test was carried out. Procedure B: The specimens were stored in water at 37°C for 3 years before sectioning and microtensile testing. During microtensile testing the beams were placed in a universal testing machine and load was applied at cross-head speed of 0.5 mm/minute. Results: For the 24-hour water storage groups, there was no significant difference in the bond strength between the different adhesives. After 3 years of water storage, the bond strength of all self-etch adhesives was significantly reduced compared to the control groups (24 hours). In contrast, the bond strength of Admira Bond was not significantly reduced. (Am J Dent 2010;23:29-33).
Address: Dr. Ali I. Abdalla, Department of Restorative Dentistry, Faculty of Dentistry, University of Tanta, Tanta, Egypt. E-mail: email@example.com
Luciano Casagrande, dds,ms, phd, LetÍcia Westphalen Bento, dds, ms, DÉbora Martini Dalpian,dds, ms Franklin GarcÍa-Godoy, dds, ms & Fernando Borba de Araujo, dds, ms, phd
Abstract: Purpose: To evaluate clinical and radiographic outcomes of indirect pulp treatment (IPT) in primary molars after long-term function (up to 60 months). Methods: Teeth with deep carious lesions without signs and symptoms of irreversible pulpitis were divided by random allocation into two groups, according to the capping material utilized over demineralized dentin: experimental group (1): self-etching adhesive system (Clearfil SE Bond); and control group (2): calcium hydroxide liner (Dycal). Both groups were filled with resin composite (Z250) and submitted to a clinical and radiographic monitoring period until exfoliation. Results: After the follow-up period (up to 60 months), no statistical difference was found between groups (P= 0.514). The overall success rate reached 78%. The failures occurred after the first year period recall. (Am J Dent 2010;23:34-38).
Address: Dr. Luciano Casagrande, School of Dentistry, Franciscan University Center (UNIFRA), Andradas 1614, Santa Maria, RS 97010 032, Brazil. E-mail: firstname.lastname@example.org
Jeong-Kil Park, dds, phd, Tae-Hyong Kim, dds, ms, Ching-Chang Ko, dds, phd, Franklin García-Godoy, dds, ms, Hyung-Il Kim, dds, phd & Yong Hoon Kwon, phd
Abstract: Purpose: To examine the effect of staining solutions on the discoloration of resin nanocomposites. Methods: Three resin nanocomposites (Ceram X, Grandio, and Filtek Z350) were light cured for 40 seconds at a light intensity of 1000 mW/cm2. The color of the specimens was measured in %R (reflectance) mode before and after immersing the specimens in four different test solutions [distilled water (DW), coffee (CF), 50% ethanol (50ET) and brewed green tea (GT)] for 7 hours/day over a 3-week period. The color difference (ΔE*) was obtained based on the CIEL*a*b* color coordinate values. Results: The specimens immersed in DW, 50ET and GT showed a slight increase in L* value. However, the samples immersed in CF showed a decrease in the L* value and an increase in the b* value. CF induced a significant color change (ΔE*: 3.1~5.6) in most specimens but the other solutions induced only a slight color change. Overall, coffee caused unacceptable color changes to the resin nanocomposites. (Am J Dent 2010;23:39-42).
Address: Prof. Yong Hoon Kwon, Department of Dental Materials, School of Dentistry, Pusan National University, Yangsan 626-870, Korea. E-mail: email@example.com
Francesco Iacono, dds, ms, Maria Giovanna Gandolfi, mbiol, dsc, mbio, phd, Bradford Huffman, bs, Jeremy Sword, bs, Kelli Agee, bs, Francesco Siboni, dds, Franklin Tay, bdsc (hons), phd,
Carlo Prati, md, dds, phd & David Pashley, dmd, phd
Abstract: Purpose: Modified
calcium-silicate cements derived from white Portland cement (PC) were
formulated to test their push-out strength from radicular dentin after
immersion for 1 month. Methods: Slabs obtained from 42 single-rooted extracted teeth were prepared with
Address: Dr. Francesco Iacono, Department of Oral Sciences, Alma Mater Studiorum, University of Bologna, Via San Vitale 59, 40125 Bologna, Italy. E-mail: firstname.lastname@example.org
Marcela Marquezan, dds, ms, phd, Raquel Osorio, dds, ms, phd, Ana Lidia Ciamponi, dds, ms, phd
Abstract: Purpose: To investigate the resistance to degradation of resin
modified glass-ionomer cement (RMGIC) and adhesive/composite restorations in
sound and simulated caries-affected dentin of primary teeth subjected to
carious challenge using a pH-cycling model and load-cycling, by means of a
microtensile test. Methods: Occlusal
cavities were prepared in 60 sound exfoliated primary second molars. Half the
specimens were submitted to pH-cycling to induce simulated caries lesion. The
teeth were randomly restored with one of the two materials: (1) a RMGIC
(Vitremer) and (2) a total-etch adhesive system (Adper Single Bond 2) followed
by resin composite (Filtek Z100). After storage in distilled water at
Address: Dr. Raquel Osorio, Avda. de las Fuerzas Armadas 1, 1B, 18014 Granada, Spain. E-mail: email@example.com
processed all-ceramic crowns
Sven Reich, priv-doz, dr med dent, Beate Brungsberg, dentist, Hubertus Teschner, dentist
& Roland Frankenberger, prof, dr med dent
Abstract: Purpose: The null hypothesis was tested: There is no difference between two all-ceramic crown systems, the Cerec method (CHAIR) and the IPS Empress method (LAB), with respect to occlusal precision and time expenditure for the dentist. Methods: 20 casts representing clinical situations were mounted in semi-adjustable articulators to serve as simulation models. The left lower first molars were prepared to receive feldspathic ceramic crowns. The minimum number of three (Min3) occlusal contacts and their desired location was defined on each crown before preparation. Two crowns were produced on each die: (CHAIR) was applied in order to simulate a chair-side treatment and [LAB] was applied to simulate the laboratory/clinical mode of production. Additionally the time required to perform the occlusal adjustment was measured. For occlusal analysis, the (Min3) were divided by the contacts that were “actually achieved” (ACT). Mean quotients for (LAB) and (CHAIR) were calculated (n = 20 each). The Wilcoxon signed rank test at P≤ 0.05 was applied to determine statistical significance. Results: The mean quotients MEAN QU (Min3)/(ACT) of 0.87 for (CHAIR) and 0.94 for (LAB) and the time expenditure for simulating intraoral occlusal adjustment of 3.44 minutes for (CHAIR) and 3.79 minutes for (LAB) did not differ significantly. (Am J Dent 2010;23:53-56).
Address: Priv.-Doz. Dr. Sven Reich, Department of Prosthodontics and Dental Materials, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany. E-mail: firstname.lastname@example.org
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