Chris S. Ivanoff, dds, Timothy L. Hottel, dds, ms, mba, Franklin GarcÍa-Godoy, dds, ms & Alan T. Riga, phd
Abstract: Purpose: To compare the enamel whitening effect of a 20-minute dielectrophoresis enhanced electrochemical delivery to a 20-minute diffusion treatment. Methods: Forty freshly extracted human teeth without detectable caries or restoration were stored in distilled water at 4°C and used within 1 month of extraction. Two different bleaching gels (Plus White 5 Minute Speed Whitening Gel and 35% Opalescence PF gel) were tested. The study had two parts: Part 1 - Quantitative comparison of hydrogen peroxide (H2O2, HP) absorption - following application of an over-the-counter 35% HP whitening gel (Plus White 5 Minute Speed Whitening Gel) to 30 (n=30) extracted human teeth by conventional diffusion or dielectrophoresis. The amount of H2O2 that diffused from the dentin was measured by a colorimetric oxidation-reduction reaction kit. HP concentration was measured by UV-Vis spectroscopy at 550 nm. Part 2 – HP diffusion in stained teeth - 35% carbamide peroxide whitening gel (35% Opalescence PF gel) was applied to 10 extracted human teeth (n=10) stained by immersion in a black tea solution for 48 hours. The teeth were randomly assigned to the 20-minute dielectrophoresis or diffusion treatment group; whitening was evaluated by a dental spectrophotometer and macro-photography. Results: Part 1: The analysis found significant differences between both groups with relative percent errors of 3% or less (a single outlier had an RPE of 12%). The average absorbance for the dielectrophoresis group in round 1 was 79% greater than the diffusion group. The average absorbance for the dielectrophoresis group in round 2 was 130% greater than the diffusion group. A single-factor ANOVA found a statistically significant difference between the diffusion and dielectrophoresis groups (P= 0.01). Part 2 - The average change in Shade Guide Units (SGU) was 0.6 for the diffusion group, well under the error of measurement of 0.82 SGU. The average change in SGU for the dielectrophoresis group was 9, significantly above the error of measurement and 14 times or 1,400% greater than the diffusion group average. A single-factor ANOVA found a statistically significant difference between the diffusion and dielectrophoresis treatment groups (P< 0.001). (Am J Dent 2011;24:259-263).
Mail: Dr. Chris S. Ivanoff, Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, 875 Union Avenue, Memphis, TN 38163, USA. E-mail: email@example.com
Hidekazu Takahashi, dds, phd, Werner J. Finger, dr med dent, phd, Tatsuo Endo, dds, phd, Masafumi Kanehira, dmd, phd, Natthavoot Koottathape, dds, ms, Masashi Komatsu, dds, phd & Markus Balkenhol, dr med dent
Abstract: Purpose: To determine basic mechanical characteristics of six commercially available nanofiller containing resin composites compared to a microhybrid and a microfilled reference material. The tested hypothesis was that there are no differences in mechanical properties between the materials. Methods: Durafill VS (DUR) and Filtek Z250 (Z250) were used as microfilled and microhybrid references. The nanofiller containing products were: Filtek Supreme XT (FIL), Grandio (GRA), Kalore (KAL), MI Flow (MIF), Tetric EvoCeram (TET), and Venus Diamond (VED). The following material characteristics were determined after 24 hours water storage (n=6): Flexural strength and modulus (FM), yield stress (0.02%), tensile strength and modulus (TM), diametral tensile strength, Knoop hardness (KHN), and fracture toughness (KIC). Results: The microfilled composite DUR consistently showed the lowest values for each property investigated. The group of nanofiller containing products could be subdivided into two groups: the nanohybrid products GRA and VED and the nanofilled FIL with higher values, on the one hand, and the flowable MIF, and the prepolymer containing composites KAL and TET, on the other. The mechanical performance of the microhybrid reference material Z250 was overall slightly better or in line with the nanohybrid and nanofilled materials. Stringent linear relationships were found between KHN and the moduli FM and TM, respectively (r> 0.95). Linear relations between the other material values investigated were moderate to high. (Am J Dent 2011;24:264-270).
Mail: Dr. Werner J. Finger, Division of Operative Dentistry, Department of Restorative Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo machi, Aoba-ku, Sendai 980-8575, Japan. E- mail: firstname.lastname@example.org
Luca Giachetti, md, dmd, msc, Daniele Scaminaci Russo, dds, Edoardo Rossi Campani, dds, Matteo Baldini, dds, Michele Nieri, dds & Marco Ferrari, md, dmd, phd
Abstract: Purpose: To compare a two-step etch-and-rinse adhesive system and a one-step self-etch adhesive system in order to evaluate the influence of clinical experience on dentin bond strength. Methods: 24 human molars were sectioned to obtain two 1 mm-thick slabs of mid-coronal dentin. Both surfaces of one of the two slabs that were obtained from each tooth were treated with a two-step etch-and-rinse adhesive (OptiBond Solo Plus), while both surfaces of the other slab were treated with a one-step self-etch adhesive (OptiBond All-In-One). 24 undergraduate, second-year students applied the adhesive on one of the two surfaces of each slab (Student group), while 12 dentists with experience in adhesive restorative dentistry (Expert group) applied the same adhesive on the other surface of the slab. Nine conical frustum-shaped resin composite (Premise Flowable) build-ups, whose smaller base was bonded to the dentin surface, were constructed on both surfaces of each dentin slab using a custom-made device. After thermocycling, specimens were subjected to microshear bond strength test. Data were analyzed by a multilevel statistical model. Results: The interaction term Experience x Adhesive resulted statistically significant (P< 0.0001). The bond strength (MPa) resulting from the self-etch adhesive was similar in the Student (27.8 ± 9.0) and in the Expert group (26.5 ± 7.0). The etch-and-rinse adhesive bond strength within the Student group (23.6 ± 10.4) was lower than that within the Expert group (28.1 ± 8.9). (Am J Dent 2011;24:271-276).
Mail: Dr. Luca Giachetti, Department of Public Health Dentistry, Viale Morgagni 85, 50134 Firenze, Italy. E- mail: email@example.com
Daniela L. Zandim, dds, ms, phd, Peter Tschoppe, dds, JosÉ E. C. Sampaio, dds, ms, phd & Andrej M. Kielbassa, dds, phd
Abstract: Purpose: To evaluate in the laboratory the effects of daily fluoride applications on remineralization of subsurface bovine enamel lesions stored in different saliva substitutes. Methods: Enamel specimens were prepared (n = 144) and demineralized (subsurface lesions; 37°C; pH 4.95; 10 days). Before and after demineralization, specimen surfaces were partly covered with nail varnish (control of sound/demineralized enamel). The specimens were either stored (5 weeks; 37°C) in mineral water (W, control, SOCP 0.7, pH 7.0), Glandosane (G, SOCP 0.3, pH 5.2), or modified Saliva Natura (SN, SOCP 2.0, pH 5.98), and were submitted to the following treatments twice daily: (0) no treatment; (ES) immersion in pure Elmex Sensitive mouthrinse (10 minutes); (D) brushing with Duraphat toothpaste/storage solution slurry (5 seconds + contact time 115 seconds; ratio 1:3); (ES+D) combination of ES and D treatments. Mineral parameters before and after storage/treatment were evaluated from microradiographs. Results: Specimens stored in G showed significantly higher demineralization compared to the other solutions (P< 0.05, ANOVA, Tukey’s post hoc test); the combined treatment with fluoride products significantly reduced the demineralizing effect of G. After 2 and 5 weeks, specimens stored in SN revealed a higher remineralization compared to the control solution (P< 0.05). Daily application of fluoride products did not promote an additional effect on remineralization of specimens stored in SN (P> 0.05). (Am J Dent 2011;24:277-283).
Mail: Dr. Peter Tschoppe, Department of Operative Dentistry and Periodontology, University School of Dental Medicine, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Assmannshauser Straße 4-6, 14197 Berlin, Germany. E- mail: firstname.lastname@example.org
Morakot Piemjai, dds, mdsc, phd, Onusa Waleepitackdej, dds, Franklin
Abstract: Purpose: To identify the remaining
demineralized dentin (the permeable layer that allows leakage) when using
primer-less wet bonding with a total etching period of 10 to 60 seconds
compared with contemporary resin adhesives. Methods: Extracted human molars were selected and Class V cavities
were prepared on the axial surfaces at the CEJ, providing margins in enamel and
dentin for leakage testing using a basic dye (n= 10). Seven groups of
conditioned teeth [1-1 etched for 10, 30, and 60 seconds (primer-less wet),
All-Bond 2 and Single-Bond 2 (wet), AQ-Bond (self-etched), Super-Bond C&B
(dry)] were used as bonding systems for resin composite restoration. All
specimens were stored in water at
Mail: Dr. Morakot Piemjai, Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant Road, Patumwon, Bangkok 10330, Thailand. E-mail: email@example.com
John D.B. Featherstone, msc, phd, George K. Stookey, phd, Michael A. Kaminski, phd & Robert V. Faller, bs
Abstract: Purpose: As a requirement of the Food & Drug Administration’s
final monograph on “Anticaries drug products for over-the-counter human use”,
the toothpaste industry has been conducting animal caries tests on every fluoride-containing toothpaste introduced into the
Mail: Dr. John D. B.
Kazuhiro Hashimoto, dds, phd, Takuichi Sato, dds, phd, Hidetoshi Shimauchi, dds, phd & Nobuhiro Takahashi, dds, phd
Abstract: Purpose: To profile plaque microflora on root-caries lesions, and to examine the protein-denaturing activity as a pilot study. Methods: Six subjects with root-caries were investigated. Plaque samples on root caries lesions (R), as well as from healthy supragingival sites (S) and periodontal pockets (≥5 mm) (P) were collected and cultured anaerobically on blood agar plates. The isolated bacteria were identified by 16S rRNA sequencing analysis, and examined for the protein-denaturing activity using the skim-milk plates and the SDS-PAGE, and for the acidogenicity using the FAB broth containing 1% glucose. Results: Propionibacterium, Actinomyces, Streptococcus, Lactobacillus and Bifidobacterium were predominant in R, while Actinomyces, Streptococcus, Veillonella and Capnocytophaga in S, and Actinomyces, Prevotella, Actinobaculum, Streptococcus, Olsenella and Eubacterium were predominant in P. Proteolytic bacteria comprised 40%, 26% and 57% of microflora in R, S and P, respectively. The skim-milk plates distinguished between protein-degrading and protein-coagulating bacteria, which comprised 7 and 33%, 0 and 26%, and 17 and 40% of microflora, in R, S and P, respectively. The SDS-PAGE analysis revealed that protein-degrading isolates were capable of degrading collagen molecules. Furthermore, the final culture pHs of protein-degrading and -coagulating bacteria were 5.0-5.4 and 3.8-3.9, respectively. The latter pH was low enough to denature proteins in skim milk. The microbial composition of R was distinct from those of S and P. (Am J Dent 2011;24:295-299).
Mail: Dr. Takuichi Sato, Division of Oral Ecology and Biochemistry, Tohoku University Graduate School of Dentistry, Sendai 980-8575, Japan. E-mail: firstname.lastname@example.org email@example.com
Ariel Sluzker, dds, ms, Michael KnÖsel, dds, dr med dent, priv doc & Athanasios E. Athanasiou, dds, msd, dr dent
Abstract: Purpose: To assess the sensitivity of digital dental photo CIE L*a*b* analysis compared to clinical spectrophotometer assessments over 6 months. Methods: CIE L*a*b* values for the upper right central incisors of 14 predoctoral dental students subjected to certain color-relevant exclusion criteria were recorded at baseline (T0), after 6 months (T1), and 1 week later (T2), using (Method 1) a spectrophotometer and (Method 2) a method of digital photo analysis. Statistical analysis of color and lightness data between both methods and time points were assessed using the Shapiro-Wilk test, Pearson’s correlation coefficient (r), Dahlberg’s formula for method error calculation, and paired samples t-tests, adopting a level of significance α= 0.05. Results: Between T0 - T1, the spectrophotometer recorded significant changes in lightness (75.51 > 77.75) and color values (a*: 3.25 > 2.38; b*: 18.47 > 17.31), whereas significant changes with Method 2 were only seen for b* (21.51 > 20.57). No significant changes for overall color and lightness changes ΔΕ to ΔΕ2 were found for either of the methods. The error of the method (T1-T2) and corresponding correlation coefficients r for values L*a*b* were found to be 1.44 / 0.43 / 0.62 (r: 0.69; P= 0.007/0.64; P= 0.14/0.9; P< 0.001) for Method 1 and 0.97/0.67/1.25 (r : 0.87; P< 0.001/0.63; P= 0.17/0.57, P= 0.04) for Method 2, respectively. (Am J Dent 2011;24:300-304).
Mail: Dr. Athanasios E. Athanasiou, Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece. E-mail: firstname.lastname@example.org
Tadeusz Faustyn KrzemiŃski, md, phd, Łukasz Gilowski, md, Rafał Wiench, md, Iwona Płocica, md, Piotr Kondzielnik, md & Andrzej SielaŃczyk, md
Abstract: Purpose: To compare the efficacy of maxillary infiltration anesthesia with 0.5% plain ropivacaine or 2% lidocaine with epinephrine 1:100,000. Methods: 60 volunteers received 1.8 ml of the anesthetic for infiltration anesthesia of maxillary central and lateral incisors and canine teeth. The onset time and duration of pulp anesthesia were assessed with an electric pulp tester. The duration time of numbness of the upper lip was also monitored. Blood pressure and heart rate were measured before and after administration of the solution. Results: The efficacy of anesthesia of the lateral and central incisors was 100% for both anesthetics. There were small insignificant differences in effectiveness of canine pulp anesthesia. The mean onset time was significantly shorter for ropivacaine – 2.2 minutes vs. 5.1 for lidocaine. Ropivacaine also had a significantly longer duration of action – mean time 79.2 minutes. Ropivacaine caused statistically significant increases in blood pressure and heart rate. (Am J Dent 2011;24;305-309).
Mail: Dr. Łukasz Gilowski, Chair, Department of Pharmacology, Medical University of Silesia, Jordana 19, 41-808 Zabrze, Poland. E-mail: email@example.com
Masao Irie, dds, phd, Noriyuki Nagaoka, me, phd, Yoshiyuki Tamada, dds, Yukinori Maruo, dds, phd, Goro Nishigawa, dds, phd, Shogo Minagi, dds, phd & Werner J. Finger, dr med dent, phd
Abstract: Purpose: To clarify the effects of the addition of silanized (S) and unsilanized (U) spherical silica filler to resin-modified glass-ionomer cement and of powder-liquid ratio on (1) the early marginal gap-width of restorations in both tooth cavities and Teflon molds, (2) the gap-formation of restorations in Class V cavities, and (3) the compressive strength of the cement. Methods: Resin-modified glass-ionomer powder (Fuji II LC EM, GC) was modified by adding 5 and 10 wt% of powder respectively, of S and U, and then the powder-liquid ratio was increased up to 4.8. Human premolars, extracted for orthodontic reasons, were used for this study. Cylindrical cavities (1.5 mm deep, 3.5 mm in diameter; one cavity was prepared in each tooth in the coronal region and medial surface) were prepared in extracted human premolar teeth and restored with resin-modified glass-ionomer cements. Each restoration margin was inspected immediately after curing and polishing (as the immediate condition was the most severe), the maximum gap-width and the opposing width (if any) were determined microscopically (n= 10). An additional test was conducted in model Class V cavities. After finishing of restorations in model Class V cavities, each tooth was sectioned in a bucco-lingual direction through the center of the restoration, and the presence or absence of gaps along the cavity interface was evaluated (n=10). Additionally, the maximum marginal gap-width and the opposing-width along margins of restorations in cylindrical Teflon molds were measured (n= 10). The compressive strengths of the restorative materials were determined immediately after light-activation (n=10). Results: Marginal gap (tooth cavity: 0.32 to 0.25-0.20%, P< 0.05; Teflon cavity: 0.94 to 0.6-0.8%, P< 0.05) and cavity adaptation (no gap in the Class V: 22 to 40-50%, P< 0.05) of the restorations improved with increasing powder-liquid ratio (3.0 to 4.4-4.8) and compressive strength increased (111 to 150-170 MPa, P< 0.05). Highly significant correlation coefficients were found for the relationships between powder-liquid ratio and (1) percentage of marginal gap width in the tooth cavity (r= -0.96, P= 0.002, n= 6), (2) gap-free tooth/cement interfaces (r= 0.90, P= 0.015, n= 6), (3) percentage of marginal gap widths in the Teflon mold (r= 0.98, P= 0.0004, n= 6) and (4) compressive strengths of the cements (r= 0.95, P= 0.004, n= 6). (Am J Dent 2011;24:310-314).
Mail: Dr. Masao Irie, Department of Biomaterials, Okayama University Graduate School of Medicine, Dentistry and Phamaceutical Sciences, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8525, Japan. E-mail: mirie＠md.okayama-u.ac.jp
Olga Polydorou, dds, dr med dent, pd, Armin KÖnig, Markus JÖrg Altenburger, dds, dr med dent, pd, Martin Wolkewitz, dr ch hum, Elmar Hellwig, dds, dr med dent, prof & Klaus KÜmmerer, dipl-chem, dr rer nat, prof
Abstract: Purpose: To evaluate the release of monomers from four different composite materials (Ceram X, Filtek Supreme XT, Tetric Flow, Tetric EvoCeram), polymerized using either halogen or LED unit. Methods: Ten specimens were made for each material/unit combination. Each specimen was stored in 1 ml 75% ethanol. The storage medium was renewed after 1, 7 and 28 days. Aliquots of this medium were analyzed by LC-MS/MS. Results: The effect of the curing unit on monomers’ release differed significantly among the materials (P< 0.0001). The amount of BisGMA and TEGDMA released from Ceram X was not influenced by the unit used (P> 0.05). Curing with LED reduced the amount of Bisphenol A released from Ceram X compared to halogen. For Filtek Supreme XT, the type of unit exerted a significant effect on the elution of BisGMA (P≤ 0.05). LED curing resulted in a higher release of TEGDMA and UDMA compared to halogen (P≤ 0.05). For Tetric Flow, LED curing resulted in lower monomer release (P< 0.0001). For Tetric EvoCeram, the amounts of BisGMA, UDMA and Bisphenol A were higher when polymerizing with LED compared to halogen. The release of substances was more material dependent and less influenced by the curing unit used. (Am J Dent 2011;24:315-321).
Mail: Dr. Olga Polydorou, Department of Operative Dentistry and Periodontology, University Medical Center Freiburg, Dental School and Hospital, Hugstetter Straße 55, 79106 Freiburg, Germany. E-mail: firstname.lastname@example.org
George K. Stookey, phd, John D.B. Featherstone, msc, phd, Marcia Rapozo-Hilo, bs, ba, Bruce R. Schemehorn, ms, Ross A. Williams, bs, Robert A. Baker, ms, Matthew L. Barker, phd, Michael A. Kaminski, phd, Christine M. McQueen, bs, mba, Jack S. Amburgey, phd, Keith Casey & Robert V. Faller, bs
Abstract: Purpose: To demonstrate the robustness of the Featherstone pH cycling model when tested in three independent laboratories and to evaluate the use of “non-inferiority” testing at those laboratories. Methods: The fundamental principles for the Featherstone laboratory pH cycling model to be an appropriate alternative to animal testing is that it must demonstrate equivalent accuracy to the “Gold Standard” (rat caries model) by: (1) providing a meaningful representation of the caries process; (2) demonstrating a proportionate response to fluoride dose (or concentration); (3) being able to show that clinically proven formulations perform similarly relative to the controls; and (4) differentiating products that have attenuated fluoride activity. Results: This cross-validation study confirmed the ability of the three independent laboratories to discriminate between various concentrations of fluoride-containing dentifrice formulations, demonstrated that clinically proven formulas perform as expected and identified an attenuated fluoride formulation (NaF/CaCO3 dentifrice - 1100 ppm NaF) as inferior compared to the 1100 ppm F- (NaF/silica) positive control. (Am J Dent 2011;24:322-328).
Mail: Dr. George K. Stookey,
Therametric Technologies, Inc.,
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