April 2010

                                                                                                                                   

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Research Article

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Benefit of the power component of sonic and rotation-oscillation modes of action for plaque removal using power toothbrushes

 

Karen  Williams, rdh, phd,  Kathy  Rapley, bs,  Jan  Haun, rdh, bs,  Pat  Walters, rdh, msdh, msob,

Julie  Grender, phd,  Tao  He, dds, phd  &  Aaron  R.  Biesbrock, dmd, phd, ms

 

Abstract: Purpose: To assess the benefit of the power component of two power toothbrushes, with sonic and rotation-oscillation mechanisms, on plaque removal efficacy. Methods: Two independent studies with identical designs were used to assess the benefit of the power component of two power toothbrushes, with sonic and rotation-oscillation mechanisms, on plaque removal efficacy. Each brush was tested with the power ‘On’ relative to a control of the same brush with the power ‘Off’ used like a manual toothbrush. The studies were carried out independently at different sites, and each employed a replicate use, single brushing, two-treatment, four-period, examiner-blind, randomized, crossover design for assessing plaque removal. Study 1 compared rotation-oscillation action (Oral-B Triumph with FlossAction brush head), and Study 2 compared sonic action (Sonicare FlexCare with ProResults standard brush head) with power on versus off. The two treatments in each study consisted of (1) brushing teeth per manufacturer’s instructions of the power toothbrush and (2) brushing without power by using the power toothbrush like a manual toothbrush. Prior to the treatment phase of each study, subjects exclusively used the assigned study toothbrush for 2 minutes twice per day according to the manufacturer’s instructions (power on) during an acclimation period. Plaque was scored at pre-brushing (baseline) and post-brushing on Visits 2, 3, 4 and 5 using the Turesky Modified Quigley-Hein Plaque Index (TMQHPI). A 2-day washout period separated each treatment period. Results: 32 subjects were enrolled in each study; 28 subjects provided complete data for Study 1 and 32 subjects provided complete data for Study 2. The adjusted mean TMQHPI plaque removal scores for Study 1 were 0.793 for the rotation-oscillation ‘On’ regimen and 0.675 for the rotation-oscillation ‘Off’ regimen. This represents a statistically significantly (P< 0.0001) greater plaque score reduction for the rotation-oscillation ‘On’ versus rotation-oscillation ‘Off’ treatment. The adjusted mean TMQHPI plaque removal scores for Study 2 were 1.042 for the sonic ‘On’ regimen and 1.007 for the sonic ‘Off’ regimen. This represents a non-significant (P= 0.426) greater plaque score reduction for the difference between sonic ‘On’ versus sonic ‘Off’ regimen. (Am J Dent 2010;23:61-64).

 

 

Address: Dr. Tao He, The Procter & Gamble Company, 8700 Mason-Montgomery Road, Cincinnati , Ohio 45040-9462 , USA . E-mail: he.t@pg.com

 

 

 

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Research Article

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Evaluation of the use of ultrasound within a power toothbrush to dislodge oral bacteria using an in vitro Streptococcus mutans biofilm model

 

Frank  A.  Roberts, dds, phd,   Beth  M.  Hacker, phd,   Teresa  K. Oswald,   Pierre  D.  Mourad, phd &  Christopher  McInnes, phd

 

Abstract: Purpose: To investigate in vitro the use of ultrasound in a power toothbrush to aid in the removal of dental plaque biofilm without bristle contact. Methods: Dental plaque was modeled using Streptococcus mutans biofilm adherent to hydroxyapatite disks. Treatment arms included positive and negative controls, disks with and without biofilm, respectively. Power toothbrush modes of action tested included a toothbrush with sonic and ultrasonic action (ULT), the same toothbrush with only sonic action (ULN), a sonic toothbrush (SON) and a rotating/oscillating toothbrush (OSC). The active element of the toothbrushes (bristles or point of ultrasound emission) was immersed in toothpaste slurry and held 3 mm away from the disk surface. Treatment included activation of the toothbrush mode of action for 5 seconds. Control disks were exposed to the same fluid environment but not exposed to a power toothbrush. After treatment, biofilm present on the disks was stained using a red dental plaque disclosing solution. Photographs were then taken and the presence of biofilm assessed using digital image analysis. For each disk a normalized pixel volume, related to the presence of biofilm corrected for lighting, was determined. Statistical testing was done with a one-way ANOVA and a Bonferroni post hoc test. Results: Normalized pixel volumes (mean ± standard deviation) were 0.428 (0.010) for the negative control and 1.022 (0.040) for the positive control. Normalized pixel volumes for the power toothbrush modes of action were 0.641 (0.075) for ULT, 0.972 (0.027) for ULN, 0.921 (0.010) for SON and 0.955 (0.025) for OSC. Statistical analysis showed a significant treatment effect (P< 0.001). All power toothbrush modes of action exhibited some biofilm removal without bristle contact in this in vitro assay. Of the modes of action tested, the combined sonic and ultrasonic mode of action (ULT) removed the greatest amount of biofilm from the disk surfaces. The same toothbrush when tested with (ULT) and without (ULN) ultrasound showed a greater amount of biofilm removed when ultrasound was present. (Am J Dent 2010;23:65-69).

 

 

Address: Dr. Frank A. Roberts, University of Washington, Department of Periodontics, Box 357444, Seattle, WA  98195-7444, USA.  E-mail: froberts@uw.edu

 

 

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Research Article

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Resistance of surface coating resins against toothbrushing abrasion

 

Emine  Suzan  Eneren, dds,  Satoshi  Imazato, dds, phd,  Andrea  Viviana  Kaneshiro, dds, phd, Yukiteru  Iwami, dds, phd,  Shigeyuki  Ebisu, dds, phd  &  Sevil  Gurgan, dds, phd

 

Abstract: Purpose: To evaluate the durability of a resin coating system after toothbrushing abrasion resistance and surface hardness of the coating resin. Methods: Rectangular blocks of Top Coat (TC) or the bonding resin of the two-step self-etching adhesive Clearfil SE Bond (SEB) were prepared by irradiation with halogen light units. After immersion in distilled water at 37°C until stabilized water absorption, the specimens were subjected to toothbrushing abrasion tests in which a toothbrush was moved on the specimen at 60 strokes/minute with a 400 gf vertical load with toothpaste slurry. The specimens were weighed after every 10,000 strokes until 200,000 strokes. Hardness of the specimen was measured with a Knoop hardness tester, and the degree of cure was determined using ATR-FTIR spectroscopy. Statistical differences between materials were analyzed using a Student's t-test. Results: TC demonstrated significantly less weight loss than SEB after 40,000 strokes (P< 0.05), showing 0.87 ± 0.64 mg loss after 200,000 strokes. The Knoop hardness number of TC was significantly greater than that of SEB (P< 0.05), and TC presented a greater degree of cure. (Am J Dent 2010;23:70-74).

 

 

Address: Dr. Emine Suzan Eneren, Hacettepe University, School of Dentistry, Department of Restorative Dentistry, Ankara, Turkey. E-mail: eneren@hacettepe.edu.tr

 

 

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Research Article

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In situ anticariogenic effect of adhesive systems containing fluoride and MDPB

 

Bruna  Maria  Covre  Garcia  da  Silva, dds, ms,  Fabiana  Mantovani  Gomes  FranÇa, dds, ms, scd,

FlÁvia  MartÃo  FlÓrio, dds, ms, scd  &  Roberta  Tarkany  Basting, dds, ms, scd, phd

 

Abstract: Purpose: To evaluate in situ the anticariogenic effect of fluoride and MDPB containing adhesive systems at the restoration interface, by microhardness tests. Methods: 120 fragments containing preparations for resin composite restorations performed at the cemento-enamel junction were randomly distributed among the adhesive systems to be tested. The adhesive systems were applied in accordance with the manufacturers’ instructions: Optibond FL, Adper Single Bond 2, Prime & Bond 2.1, Optibond Solo Plus, Adper Prompt, Clearfil Protect Bond and restored with the nanoparticulate resin composite Z350. Twenty volunteers used a palatal appliance containing fragments restored with each adhesive system for 21 days, and applied 20% sucrose on them eight times a day to simulate a high cariogenic challenge. Microhardness tests were performed at different depths (20 µm, 40 µm and 60 µm from the occlusal margin of the restoration) and at different distances (100 µm, 200 µm and 300 µm from the adhesive interface). Results: ANOVA showed that for enamel, there was significant difference between the adhesive systems (P= 0.0106); the interaction adhesive system*distance was a significant (P= 0.0006), and the one-step self-etching adhesive system containing fluoride (Adper Prompt) presented a higher anticariogenic effect. However, for dentin, the adhesive system used did not interfere in decreasing the severity of caries formation. (Am J Dent 2010;23:75-80).

 

 

Address: Prof. Dr. Roberta Tarkany Basting, Department of Restorative Dentistry - Operative, Faculty of Dentistry and Center for Dental Research São Leopoldo Mandic, Rua José Rocha Junqueira, 13, Bairro Swift, Campinas, SP, CEP: 13045-755, Brazil. E-mail: rbasting@yahoo.com

 

 

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Research Article

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Effect of different onlay systems on fracture resistance and failure pattern

of endodontically treated mandibular molars restored with and without glass fiber posts

 

Ziad Salameh, dds, msc, phd, ficd, Hani F. Ounsi, dcd, dese, msc, mracd(endo), ficd, Moustafa N. Aboushelib, dds, phd,  Rana Al-Hamdan, bds, msc,  Walid Sadig, bds, msc  &   Marco Ferrari, dds, phd

 

Abstract: Purpose: To investigate the relationship between post and core build-up materials on the fracture resistance of endodontically treated teeth restored with different onlay restorations. Methods: 60 mandibular molars were endodontically treated and divided into three experimental groups that received one of the following onlay restorations: gold onlays, glass ceramic onlays (Empress I), or resin composite onlays (Gradia). Half of the specimens in each group received a fiber post (n= 10). Two controls groups (n= 10) were included: one group composed of sound mandibular molars, and the second group was composed of endodontically treated unrestored molars. Fracture tests were carried out by applying axial load using a universal loading machine until fracture. All fractured specimens were fractographically examined using a scanning electron microscope (SEM). Data were analyzed using two-way ANOVA and Tukey multiple comparison tests (α= 0.05). Results: Statistical analysis showed that restoration of endodontically treated teeth with gold onlays improved fracture resistance when compared to glass ceramic or resin composite onlays. The presence of a fiber post significantly improved (P< 0.045) fracture resistance of gold onlays from 2271 to 2874N while it did not influence the performance of the other two groups. Fractographic analyses revealed that the presence of fiber post resulted in more restorable fractures due to better stress distribution of the applied load. All onlay systems resulted in significant improvement of the fracture resistance compared to unrestored teeth (711N) but neither of them resulted in restoring the fracture resistance to match that of sound teeth (3212 N). (Am J Dent 2010;23:81-86).

   

Address: Prof. Dr. Marco Ferrari, Department of Dental Sciences, University of Siena, Policlinico Le Scotte, Viale Bracci, 53100 Siena, Italy.  E-mail: ferrarimar@unisi.it

 

 

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Research Article

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Clinical evaluation of an all-ceramic restorative system: A 36-month clinical evaluation

 

Douglas Barnes, dds , ms ,  James C. Gingell, dds, ms,  David George, DDS, mba,  Erika Adachi, dds, Steven Jefferies, ms, dds, phd  &  Veeraraghavan V. Sundar, phd

 

Abstract: Purpose: To clinically evaluate an all-ceramic restorative system (Finesse All-Ceramic) when used in conjunction with an ultra-low fusing porcelain (Finesse) using bonded esthetic resin cements (Enforce & Calibra). Methods: This report describes the 3-year results of a prospective, consecutive case clinical evaluation for Finesse All-Ceramic. Forty posterior and anterior crowns, 20 all ceramic inlays and onlays, and 26 veneers were placed in 43 patients at the initiation of this study. Standard ceramic preparations were performed followed by conventional polyvinylsiloxane (Aquasil) impression techniques using cord retraction. The bonded resin cement was used to place the restorations following manufacturer’s instructions. Results: A majority of restorations (95-100%) were evaluated to be optimal at baseline (B), 1 month, 12, 24 and 36 months using a modified Ryge criteria for the following categories: color match, marginal adaptation, porcelain staining, secondary caries, postoperative sensitivity, and retention. Assessment of color match at 36 months resulted in 97% of all crowns and 100% of all veneers and onlays being rated alfa for shade match to Vita Lumin shade guide. The overall 3-year success rate at the 3-year recall (inlay/onlays, crowns, and veneers) was 98.57%, with the success rate for crowns and veneers at this time period being 100%. (Am J Dent 2010;23:87-92).

 

 

 

 

Address: Dr. Douglas M. Barnes, Director, Advanced Education in General Dentistry, Baltimore College of Dental Surgery Dental School , University of Maryland , 666 West Baltimore Street, Baltimore , MD 21201-1586 , USA . E-mail:dbarnes@umaryland.edu

 

 

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Research Article

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Evaluation of three different adhesive systems using a bacterial method to develop secondary caries in vitro

 

Luciana Cardoso Espejo, ms,  Maria Regina Lorenzetti Simionato, phd, Lucia Pereira Barroso,

phd, Narciso Garone Netto, phd  &  Maria Aparecida Alves de Cerqueira Luz, phd

 

Abstract: Purpose: To assess the effects of three different dental adhesive systems on the formation of secondary root caries, in vitro, with a standardized interfacial gap in a filled cavity model. Methods: 40 sound human molars were selected and randomly assigned to four experimental groups: Clearfil SE Bond (CSEB), Xeno III (X-III), Scotchbond Multi-Purpose Plus (SBMP) and negative control (NC) without an adhesive system. After the standardized Class V cavity preparations on the buccal and lingual surfaces, restorations were placed with resin composite (Filtek Z250) using a standardized interfacial gap, using a 3 x 2 mm piece of 50 µm metal matrix. The teeth were sterilized with gamma irradiation and exposed to a cariogenic challenge using a bacterial system with Streptococcus mutans. Depth and extension of wall lesions formed and the depth of outer lesions were measured by software coupled with light microscopy. Results: For wall lesion extension the ANOVA test showed differences between groups except between X-III and SBMP (P= 0.294) . The Tukey’s test of confidence intervals indicated smaller values for the CSEB group than for the others. For wall lesion depth the CSEB group also presented the smallest mean values of wall lesion depth when compared to the others (P< 0.0001) for all comparisons using Tukey’s test. Regarding outer lesion depth, all adhesives showed statistically similar behavior. SEM evaluation of the morphologic appearance of caries lesions confirmed the statistical results showing small caries lesion development for cavities restored with CSEB adhesive system, which may suggest that this adhesive system interdiffusion zone promoted a good interaction with subjacent dentin protecting the dental tissues from recurrent caries. (Am J Dent 2010;23:93-97).

 

 

Address: Dr. Maria Aparecida Alves de Cerqueira Luz, Rua Duarte de Azevedo, 284, cj. 22, Santana, São Paulo, SP, CEP: 02036-021, Brazil.  E-mail: maacluz@usp.br

 

 

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Research Article

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Adhesion of resin core foundation composites to root canal dentin using different dentin adhesives

 

Penprapa  Wattanasukchai, dds,  Rangsima  Sakoolnamarka, dds, phd  &  Mansuang Arksornnukit, dds, ms, phd

 

Abstract: Purpose: To evaluate the microtensile bond strengths (µTBS) of two core composites; LuxaCore and MultiCore Flow, to root canal dentin when using different adhesive systems. Methods: Bonded specimens were allocated into six groups (N= 20) according to the combination of two core composites and three adhesive systems (All-Bond 2, Excite DSC and Contax). The materials were used according to the manufacturers’ instructions. The µTBS were measured using a universal testing machine with a crosshead speed of 1 mm/minute. Data were analyzed utilizing two-way ANOVA (α= 0.05). Results: Excite DSC showed the highest mean µTBS, which was significantly different from those of All-Bond 2 and Contax in LuxaCore groups. Excite DSC showed the highest µTBS but significant differences (P= 0.154) were not detected in MultiCore groups. There were significant differences in µTBS between two resin composites (P< 0.001). With Contax, µTBS of MultiCore Flow to dentin were significantly higher than those of LuxaCore (P= 0.003). (Am J Dent 2010;23:98-102).

 

 

Address: Dr. Mansuang Arksornnukit, Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University , Bangkok , 10300, Thailand .  E-mail: mansuang@yahoo.com

 

 

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Research Article

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Morphological characteristics of the interface between resin composite and

glass-ionomer cement to thin-walled roots: A microscopic investigation

 

Mohamed F. Ayad, bds, mscd, phd,  Salma A. Bahannan, bds, ms  &  Stephen F. Rosenstiel, bds, msd

 

Abstract: Purpose: To identify how different treatments of the root dentin surface affect the microscopic appearance of the resin composite/glass-ionomer cement-to-dentin interface. Methods: The root canals of 70 extracted human single-rooted teeth were enlarged to reduce dentin wall thicknesses to 0.5 mm. The roots were randomly divided into seven test groups (n= 10) according to the canal irrigant used: no irrigant (control), 5% hydrogen peroxide, 5% sodium hypochlorite, a combination of 5% hydrogen peroxide and sodium hypochlorite, 15% ethylenediaminetetraacetic acid (EDTA), 10% lactic acid, or 20% lactic acid. To simulate thin-walled roots, within each group, crowns were sectioned and the entire surface of each root canal space was enlarged with Profile instrument. Half of treated root canals (n= 5) were filled with resin composite (PermaFlo) and the other half were filled with glass-ionomer cement (Fuji II LC). A light-transmitting plastic post (Luminex) was used to create space for a fiber-reinforced post and to ensure polymerization of the restorative material. Specimens were critical-point dried and freeze fractured for scanning electron microscope analysis. Three sites along the root were evaluated (cervical, middle, and apical). Results: Scanning electron micrographs showed no differences in the morphology of the resin tags at the cervical, middle or apical levels with any of the irrigants or the restorative materials used. Also, no difference in surface topography was found within individual groups. A resin-dentin interdiffusion zone and resin tags developed after application of resin composite with lactic acid solutions and EDTA but not with the glass-ionomer cement. (Am J Dent 2010;23:103-107).

 

 

Address: Dr. Mohamed F. Ayad, P.O. Box 80209 , Jeddah 21589 , Saudi Arabia .  E-mail: ayadmf@hotmail.com

 

 

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Research Article

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Mechanical characterization of sclerotic occlusal dentin by nanoindentation and nanoscratch

 

Noelia MartÍn, dds, Alvaro GarcÍa, md, Vicente Vera, md,  Miguel Ángel Garrido, phd

& JesÚs RodrÍguez, phd

 

Abstract: Purpose: To evaluate the mechanical properties of occlusal wear lesions identified as sclerotic. Methods: Nanoindentation and nanoscratch techniques have been applied to determine elastic modulus (E), hardness (H) and wear resistance of different types of sclerotic dentin. Nanoscratch testing was applied to evaluate the tribological behavior. Mechanical properties of sclerotic dentin were evaluated together with scanning electron micrographs to show the different degree of tubular occlusion. Results: The higher the degree of sclerosis, the lower were the measured mechanical properties. The highest values (E = 20 GPa and H = 0.67 GPa) were obtained in normal dentin, and the lowest (E = 11.4 GPa and H = 0.51 GPa) in severe sclerotic lesions. These differences were statistically significant (P< 0.05). The groove width in the nanoscratch tests was also higher for moderate or severe sclerosis than for normal dentin. (Am J Dent 2010;23:108-112).

 

 

Address: Dr. Jesús Rodríguez Pérez, School of Experimental Sciences and Technology, Department of Science and Materials Engineering, Rey Juan Carlos University, C. Tulipán s/n, E 28933 Móstoles, Madrid, Spain. E-mail: jesus.rodriguez.perez@urjc.es

 

 

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Research Article

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Effect of the diffusion of bleaching agents through enamel on dentin bonding at different depths

 

Adriano  Fonseca  Lima, dds, ms,  FabrÍcio  MaurÍlio  da  Silva  Fonseca, DDS,

Andrea  NÓbrega  Cavalcanti, dds, ms, phd,  FlÁvio  Henrique  Baggio  Aguiar, dds, ms, phd

&  Giselle  Maria  Marchi, dds, ms, phd

 

Abstract: Purpose: To evaluate the influence of two concentrations of bleaching agents applied over enamel surfaces on the dentin bonding at different depths. Methods: Twenty-four bovine incisors were sectioned, obtaining three fragments per tooth (4x4 mm). Each fragment presented a 0.7 mm enamel thickness; and the dentin thickness varied according to the experimental group: 0.5 mm, 1 mm or 1.5 mm. Fragments from each dentin-thickness were allocated into three groups (n=8): G1: Control (no bleaching); G2: 16% carbamide peroxide (6 hours/14 days); G3: 35% hydrogen peroxide (three 15-minute treatments). 24 hours after enamel bleaching, the adhesive system was applied and dentin surfaces were restored with resin composite cylinders (2 mm diameter and 1 mm height). The micro-shear testing was performed immediately after restorative procedures, at a speed of 0.5 mm/minute until failure. Bond strength values, in MPa, were statistically analyzed (split-plot ANOVA/Tukey α= 0.05). Results: Means obtained were: G1-0.5 mm: 13.5, G1-1 mm: 9.48, G1-1.5 mm: 9.01; G2-0.5 mm: 9.64, G2-1 mm: 9.44, G2-1.5 mm: 9.27; G3-0.5 mm: 11.68, G3-1 mm: 11.64, G3-1.5 mm: 7.63. Regardless of the dentin thickness, bleached groups presented bond strengths similar to that of control groups. Nevertheless, significant differences among dentin depths were detected (P= 0.02); and the lowest bond strength was observed on the deepest dentin (1.5 mm). The diffusion of bleaching agents through enamel surfaces did not affect the bond strength to dentin, which is highly dependent on the morphology/depth of the substrate. (Am J Dent 2010;23:113-115).

 

 

 

 

Address: Prof. Dr. Giselle Maria Marchi, Department of Restorative Dentistry, Faculty of Dentistry of Piracicaba – UNICAMP, Av. Limeira - Areião, CEP: 13414-903, Piracicaba, SP, Brazil.  E-mail: gimarchi@fop.unicamp.br

 

 

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Research Article

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Effect of immediate and delayed post space preparation on coronal bacterial microleakage in teeth obturated with a methacrylate-based sealer

with and without accelerator

 

Osvaldo Zmener, dds, dr odont,  Cornelis H. Pameijer, dmd, mscd, dsc, phd  &  Susana Alvarez Serrano, dds

 

Abstract: Purpose: To investigate the sealing properties of root fillings with resin-coated gutta-percha cones and a methacrylate-based resin endodontic sealer with and without an accelerator component in root canals subjected to immediate or delayed post space preparation. Methods: Forty-eight extracted human teeth with single straight root canals were treated endodontically. Specimens were then assigned to four groups of 10 teeth each (n= 10). After autoclaving, the following operative procedures were carried out under strict aseptic conditions. In Group 1 the root canals were filled with resin-coated gutta-percha cones and a methacrylate based resin endodontic sealer (EndoREZ). Post space preparations were performed 2 minutes after the sealer had set. In Group 2 the root canals were filled as in Group 1 but with the addition of a chemical accelerator. The post space preparations were also performed 2 minutes after the sealer had set. Groups 3 and 4 were filled as in Groups 1 and 2 respectively, however the post space preparations were done 7 days after the root canal filling was completed. One positive and one negative control tooth per group was added. All specimens were subjected to a coronal bacterial leakage of E. faecalis during a 60-day period using a dual chamber microbial leakage model. Data was analyzed among groups with the Kaplan-Meier survival analysis while significant pairwise differences were analyzed with the log-rank test (P< 0.05). Results: No significant differences (P> 0.05) in bacterial leakage were observed between Groups 1 and 2 and between Groups 3 and 4. However, Groups 1 and 2 differed significantly from Groups 3 and 4 (P< 0.05). (Am J Dent 2010;23:116-120).

 

 

Address: Dr. Cornelis H. Pameijer, 10 Highwood, Simsbury, CT 06070, USA.  E-mail: cornelis@pameijer.com

 

 

 

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Research Article

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Sealing properties of a calcium aluminate luting agent

 

Cornelis H. Pameijer, dmd, mscd, dsc, phd, Osvaldo Zmener, dds, dr odont, Susana Alvarez Serrano, dds &  Franklin Garcia-Godoy, dds, ms

 

Abstract: Purpose: To determine the self-sealing properties of Ceramir C&B, a new calcium aluminate-based luting material and to compare it to two commercially available cements, using a bacterial model system. Methods: 30 premolars were prepared in a standardized fashion with a total angle of convergence of approximately 10-12º for complete cast restorations. All margins were placed in dentin. Gold copings were fabricated in a Type III alloy using standardized laboratory methods. Thirty teeth were randomly assigned to three groups of 10: Group 1: Ceramir C&B (CM), a calcium aluminate/glass ionomer hybrid (formerly XeraCem), Group 2: Ketac-Cem (KC), a glass-ionomer cement (control) and Group 3: Rely X Luting Plus (RX), a resin-modified glass-ionomer cement. After cementation the samples were allowed to bench set for 10 minutes, after which they were subjected to thermal cycling (x2000, between 5 and 55°C, dwell time 35 seconds) and then stored in sterile phosphate buffer for 7 days at 37°C. Subsequently the occlusal surface was carefully reduced exposing the dentin. Finishing on wet sand paper removed the gold flash from grinding. After sterilization the specimens were subjected to bacterial microleakage in a dual chamber apparatus for a period of 60 days. Turbidity was recorded daily. The data were analyzed using the Kaplan-Meyer survival analysis and the log-rank test (P< 0.05). Results: A statistical analysis demonstrated that the groups cemented with CM and RX showed no significant difference in microleakage patterns (P> 0.05), while both recorded significantly lower microleakage scores (P< 0.05) than the group cemented with KC. (Am J Dent 2010;23:121-124).

 

 

Address: Dr. Cornelis H. Pameijer, 10 Highwood, Simsbury, CT 06070, USA. E-mail: cornelis@pameijer.com

 

 

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