August 2010

Research Article

The evaluation of fluorescence changes after application of casein

phosphopeptides (CPP) and amorphous calcium phosphate (ACP)

on early carious lesions

 

Markus JÖrg Altenburger, dr,   Birgit Gmeiner, dr,   Elmar Hellwig, prof dr , 

Karl-Thomas Wrbas, priv-doz. dr  &   JÖrg Fabian Schirrmeister, priv-doz. dr

 

Abstract: Purpose: To evaluate the effect of casein phosphopeptides (CPP) and amorphous calcium phosphate (ACP), as an adjunct to average oral hygiene, on the fluorescence of initial carious fissures and pits in vivo. Methods: For this investigator-blind in vivo study 32 volunteers were recruited. Subjects with premolars and molars showing DIAGNOdent-values between 15 and 20 were randomly assigned to two treatment groups. During a wash-out period of 2 weeks and during the 3-week treatment period all subjects were instructed to use only standard fluoride toothpaste (1450 ppm F- as NaF) and to abstain from any oral hygiene products other than dental tape. During the treatment period, one group additionally applied a CPP-ACP containing cream on the respective fissures for 3 minutes, once per day. At Days 1, 8, 15, and 22, DIAGNOdent measurements and a visual assessment of the fissures were performed by two calibrated independent examiners. Results: No significant changes of DIAGNOdent values were found in the con­trol group during the study period. Fissures additionally treated with the CPP-ACP containing cream showed signifi­cantly lower laser fluorescence values after Day 15 (P= 0.001) and Day 22 (P< 0.001) compared to the control group. No significant difference in the visual classification between the two groups could be found. (Am J Dent 2010;23:188-192).

 

 

 

 

Address: Dr. Markus J. Altenburger, Department of Operative Dentistry and Periodontology, University Medical Hospital and Dental School, Albert-Ludwigs-University Freiburg, Hugstetter Straße 55, 79106 Freiburg, Germany. E-mail: markus.altenburger@uniklinik-freiburg.de

 

 

Research Article

Protective effect of NaF/triclosan/copolymer and MFP dentifrice on enamel erosion

 

Vanara FlorÊncio Passos, dds, msc,  SÉrgio Lima Santiago, dds, msc, phd, 

LÍvia Maria AndalÓ Tenuta, dds, msc, phd   &   Jaime Aparecido Cury, dds, msc, phd

 

Abstract: Purpose: To evaluate in situ the protective effect of sodium fluoride (NaF)/triclosan/copolymer dentifrice compared with monofluorphosphate (MFP) dentifrice on eroded enamel. Methods: The specimens were subjected to erosion with cola soft drink for 60 seconds, four times a day, for 5 days, followed by treatment with the slurry of non-fluoridated, NaF (1450 ppm F/triclosan/copolymer) or MFP (1450 ppm F) dentifrices. Their effects were assessed by surface hardness loss. Results: The dentifrice containing NaF/triclosan/copolymer was statistically more effective on reduction of enamel acid erosion than the non-fluoride and the MFP dentifrice (P< 0.05). (Am J Dent 2010;23:193-195).

 

 

 

Address: Dr. Sérgio Lima Santiago, Rua Monsenhor Furtado s/no., CEP 60430-350 Fortaleza, CE, Brazil.  E-mail: sergiosantiago@yahoo.com

 

 

 

 

 

 

 

 

Research Article

Effect of toothpaste containing d-limonene on natural

extrinsic smoking stain: A 4-week clinical trial

 

Ping Xie, dds,  Junjun Lu, bs,  Huchun Wan, dds  &  Yuqing Hao, dds, phd

 

Abstract: Purpose: To determine whether natural smoking stain could be removed/inhibited effectively by a toothpaste containing 5% d-limonene. For comparison and contrast, the effects of d-limonene on tea stain were also assessed. Methods: The design was a randomized controlled double-blind trial with parallel groups. Toothpastes were: A: positive control with perlite whitening formulation; B: A+5% d-limonene; C: D+5% d-limonene; D: negative control. The extrinsic stains were measured using Lobene Stain Index. Following baseline examination, all subjects were randomly assigned to one of the four toothpaste groups and instructed to brush with the assigned products twice daily. Subjects returned to the clinic after 4-week brushing for stain removal assessment, then all extrinsic stains, plaque and supragingival calculus were removed and use of assigned products was continued for another 4 weeks, and the stain scores were repeated for inhibition assessment. Results: A total of 408 subjects, 201 with smoking stains and 207 with tea stains, participated in the trial. 5% d-limonene combined with Perlite whitening formulation significantly reduced stain scores both for smoking stain removal and inhibition (P< 0.05). Furthermore, 5% d-limonene alone (in negative formulation) exhibited an additional advantage for smoking stain inhibition (P< 0.05), but the advantage was not found for long-standing smoking stain removal (P> 0.05). The additional advantage of 5% d-limonene was shown neither for removal nor for inhibition in the tea stain study (P> 0.05). All test products were well tolerated over the study period. (Am J Dent 2010;23:196-200).

 

 

Address: Dr. Hao Yuqing, State Key Laboratory of Oral Diseases, Sichuan University, No. 14 Renmin South Road 3rd Section, Chengdu, Sichuan 610041, China.  E-mail:  hyqluxi@126.com

 

 

Research Article

Polytetrafluoroethylene added to acrylic resin: Surface properties

and Candida albicansadherence

 

Fabiana Gouveia Straioto, dds, msc, Renata Alves, dds, Antonio Pedro Ricomini Filho, dds 

&  Altair Antoninha Del Bel Cury, dds, msc, phd

 

Abstract: Purpose: To evaluate the surface properties and Candida albicans adherence on two acrylic resins, one polymerized by long cycle and the other by short polymerization cycle, with added 2% PTFE (wt/wt) (experimental groups) or not added (control groups). Methods: The specimens were divided into four groups (n= 10 per group): (1) acrylic resin polymerized by long cycle; (2) acrylic resin polymerized by long cycle with added 2% PTFE; (3) acrylic resin polymerized by short cycle; and (4) acrylic resin polymerized by short cycle with added 2% PTFE. After finishing and polishing, all specimens were assessed for their surface roughness (μm), contact angle (º) and surface free energy (erg/cm^-2). Saliva-coated specimens were submitted to the adherence assay with C. albicans (ATCC 90028). Adhered cells were detached from the acrylic resin surface by ultrasonic waves at 7 watts for 30 seconds in phosphate buffered saline solution (PBS). This cell solution was serially diluted in PBS and plated on Sabouraud agar. The results were expressed in colony forming units per surface area (CFU/mm²). The data was analyzed by two-way ANOVA. The significance limit was set at 5%. Results: No statistical differences were found for roughness, contact angle and surface free energy. There was a reduction trend in C. albicans adherence in PTFE added to resins, but it was not statistically significant. (Am J Dent 2010;23:201-204).

 

 

 

 

Address: Prof. Altair Antoninha Del Bel Cury, Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, P.O. Box 52, 13414-903, Piracicaba, SP, Brazil. E-mail: altcury@fop.unicamp.br

 

 

 

Research Article

Effect of DPSS laser on the shear bond strength of orthodontic brackets

 

Soo-Byung  Park, dds, phd,  Eun-Hee  Kang, dds, ms,  Woo-Sung  Son, dds, phd,  Ching-Chang  Ko, dds, phd, Hyung-Il  Kim, dds, phd  &  Yong Hoon  Kwon, phd

 

Abstract: Purpose: To test the bonding of orthodontic brackets to teeth using a diode-pumped solid state (DPSS) laser. Methods: A total of 60 extracted human teeth were divided randomly into four groups: Group 1 (control) - the brackets were bonded to teeth using the quartz-tungsten-halogen (QTH) light (800 mW/cm²) for 40 seconds; Groups 2-4 - the brackets were bonded to teeth using the DPSS laser (500 mW/cm²) for 40 seconds, 20 seconds, and 10 seconds, respectively. The teeth were debonded using shear force in a universal testing machine, and the amount of residual adhesive remaining on each tooth was evaluated. Statistical analysis was carried out for the shear bond strength (SBS) and Adhesive Remnant Index (ARI). Results: The brackets bonded using the DPSS laser for 40 seconds showed the highest mean SBS (13.1±1.2 MPa) among the groups. Furthermore, the DPSS laser with 10 seconds light-curing could achieve 83% of the mean SBS obtained using the QTH light for 40 seconds. The ARI scores showed no differences among all four groups suggesting a similar failure mode. (Am J Dent 2010;23:205-207).

 

 

Address: Prof. Yong Hoon Kwon, Department of Dental Materials, School of Dentistry and Medical Research Institute, Pusan National University, Yangsan 626-870, Korea.  E-mail: y0k0916@pusan.ac.kr

 

 

Research Article

Gloss and surface roughness produced by polishing kits on resin composites

 

Ramtin Sadidzadeh, dds, ms, Deniz Cakir, dds, ms, Lance C. Ramp, dmd, phd  &  John O. Burgess, dds, ms

 

Abstract: Purpose: To compare in vitro the surface roughness (Ra) and gloss (G) produced by three conventional and one experimental polishing kits on four resin composites. Methods: 24 discs were prepared (d= 12 mm, t= 4 mm) for each resin composite: Filtek Supreme Plus Body/A2 (FSB), Yellow Translucent (FST), Heliomolar/A2 (HM), and EsthetX/A2 (EX) following the manufacturers’ instructions. They were finished with 320 grit silicon carbide paper for 80 seconds each. Polishing systems: Sof-Lex, Enhance-Pogo, Astropol and Experimental Discs/EXL-695, were applied following manufacturers’ instructions. Each specimen was ultrasonically cleaned with distilled water and dried. Gloss and Ra were measured with a small area glossmeter (Novo-curve) and non-contact profilometer (Proscan 2000) following ISO 4288, respectively. The results were evaluated by two-way ANOVA followed by separate one-way ANOVA and Tukey/Kramer test (P= 0.05). Results: There was a significant interaction of surface roughness and gloss between the composites and polishing systems (P< 0.05). The lowest surface roughness was recorded for FST polished with the Experimental kit. The highest gloss was obtained for FSB composite polished with the Experimental kit. The experimental polishing system produced smoothest surfaces (P< 0.05). The Enhance-Pogo and the experimental polishing kit produced highest gloss (P< 0.05). (Am J Dent 2010;23:208-212).

 

 

 

 

Address: Dr. Ramtin Sadidzadeh, Department of Prosthodontics, School of Dentistry Room #537, University of Alabama at Birmingham, 1919 7th Avenue South, Birmingham, AL 35294-0007, USA.  E-mail: rsadidz@uab.edu

 

 

Research Article

Bond strength of different veneering ceramics to zirconia

and their susceptibility to thermocycling

 

Markus B. Blatz, dmd, phd,  Michael Bergler, cdt, mdt,  Fusun Ozer, dmd, phd,  Stefan Holst, dmd, phd, Jin-Ho Phark, dds, dr med dent   &   Gerard J. Chiche, dds

 

Abstract: Purpose: To evaluate the bond strength of recently developed feldspathic veneering ceramics to zirconium-oxide ceramic core material (Y-TZP). In addition, the effect of thermocycling on the bond strength was investigated. Methods: 90 square Lava framework Y-TZP specimens were randomly assigned to three groups (n=30) and veneered with one of the three zirconia veneering ceramics Cerabien ZR (CZR), GC Initial (GCI), or Lava Ceram (LC). 30 additional metal-ceramic specimens served as the control (VO). 15 specimens per group were stored in a saline solution for 3 days. To test the durability of the bond, 15 specimens per group were thermocycled for 10,000 cycles between 5° to 60º C with a 15-second dwell time. Shear strength was tested with an Instron universal testing system. A two-way ANOVA model and Tukey’s HSD were applied for statistical analyses (α= 0.05). Results: The different material combinations revealed significantly different shear bond strength values (CZR>GCI>LC>VO). All veneering ceramic/zirconia combinations showed significantly higher bond strength than the metal-ceramic control VO. Bond strength values were not affected by thermocycling, except for CZR, which had significantly higher bond strength after thermocycling. Microscopic evaluation of failure modes revealed 100% cohesive failures in the veneering ceramic for all specimens. (Am J Dent 2010;23:213-216).

 

 

 

 

Address: Dr. Markus B. Blatz, Dept. of Preventive and Restorative Sciences, Robert Schattner Center, University of Pennsylvania, School of Dental Medicine, 240 S. 40th Street, Philadelphia, PA 19104, USA. E-mail: mblatz@dental.upenn.edu

 

 

Research Article

Effect of chlorhexidine concentrations on micro-shear bond strength

of self-etch adhesive to normal and caries-affected dentin

 

Enas H. Mobarak, bds, mds, ddsc,   Dalia I. El-Korashy, bds, mdsc, phd   &   David H. Pashley, dmd, phd

 

Abstract: Purpose: To evaluate the effect of different chlorhexidine concentrations on bond strength of resin composite to normal and caries-affected dentin using a self-etch primer adhesive. Methods: Thirty carious human molars were ground to expose flat dentin surfaces containing caries-affected surrounded by normal dentin. The teeth were divided into three groups. One group received no chlorhexidine pretreatment (control). The second and third groups received 2% or 5% chlorhexidine pretreatments, respectively before applying the self-etch primer adhesive (Clearfil SE Bond). Resin composite was applied to caries-affected dentin and to normal dentin on the same tooth with the aid of polyethylene tubes (0.9 mm diameter and 0.7 mm height). For micro-shear bond strength testing, each tooth was secured in a specially designed attachment jig to hold the specimens to the universal testing machine. Load was applied by the testing machine through a wire loop adjusted to the bonded interface at a crosshead speed of 0.5 mm/minute. Micro-shear bond strength was calculated and mode of failure was examined with a x40 stereomicroscope. Results: Statistical analysis revealed insignificant differences between control, 2% and 5% chlorhexidine pretreatment for normal as well as for caries-affected dentin groups. Also, there were insignificant differences in bond strength values between normal and caries-affected dentin for each treatment modality. Adhesive failure was the most common mode of failure. (Am J Dent 2010;23:217-222).

 

 

Address: Dr. Enas H. Mobarak, Associate Professor of Restorative Dentistry, Department of Restorative Dentistry, Faculty of Oral and Dental Medicine, Cairo University, 29 El-Zahraa St. Dokki, Giza, Cairo, 12311 Egypt.  E-mail: enasmobarak@hotmail.com

 

 

Research Article

Temperature rises beneath resin composite restorations during curing

 

Shlomo  Matalon, dmd,  Hagay  Slutzky, dmd,  Nadav  Wassersprung, dmd,  Iris  Goldberg-Slutzky, dmd &  Ariel Ben-Amar, dmd

 

Abstract: Purpose: To compare the thermal conductivity of two different composite materials, with five light-cure units, in a series of different material thicknesses and light source distances. Methods: Two commonly used resin composite restorative materials and three light emitting diodes (LED), one halogen, and one plasma arc lights were selected. The thermal conductivity of the composite materials with different light curing units (LCU) was measured and compared. A K-type thermocouple and digital thermometer were used to assess the thermal conductivity. Materials depths of 1 mm , 2 mm and 4 mm and curing distances of 0 mm , 3 mm and 6 mm were compared. Four-way ANOVA was used to analyze the Ln transformation of the maximal temperature and a Tukey test for multiple comparisons. Results: Significant differences in temperature rise were observed between the two restorative materials. The thermal emission of the LED lights was higher than the other LCU's measured. An inverse ratio was found between material thickness and the measured thermal conductivity and the distance of the light tip from the restorative material. (Am J Dent 2010;23:223-226).

 

 

Address: Dr. Shlomo Matalon, Department of Oral Rehabilitation, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Ramat-Aviv 69948, Israel. E-mail: matalons@post.tau.ac.il

 

 

Research Article

Comparison of fracture resistance of bonded glass fiber posts

at different lengths

 

Remo  Schiavetti, dds,  Franklin  GarcÍa-Godoy, dds, ms,  Manuel  Toledano, dds, phd,

Claudia  Mazzitelli, dds, msc, phd,  Alberto  Barlattani, md, dds,  Marco  Ferrari, md, dds, phd

&  Raquel  Osorio, dds, phd

 

Abstract: Purpose: To evaluate in vitro the fracture resistance of quartz fiber posts for three different dowel lengths. Methods: 30 single-rooted human premolars with similar root length and diameter were endodontically treated and randomly divided into three experimental groups (n=10) according to the post space depth created: (1) 5 mm; (2) 7 mm; (3) 9 mm. Quartz fiber posts (Endo Light post) were cemented using a dual cured resin cement with its adhesive system (Prime&Bond NT + Fluorocore 2). After 24 hours, specimens were embedded in acrylic resin and loaded under continuous compressive force at the extruding coronal part of the post (45-degree angle) to the long tooth axis (cross-head speed: 0.75 mm/minute). Forces at fracture (Newtons) were recorded. One-way ANOVA and Tukey tests were used for the statistical analysis (P< 0.05). Results: Mean strength values (SD) were: (1) 40.52 (3.14); (2) 41.68 (5.31); (3) 44.88 (6.77), respectively. No statistically significant differences were found among the groups. (Am J Dent 2010;23:227-230).

 

 

Address: Prof. Marco Ferrari, University of Siena, School of Dental Medicine, Department of Fixed Prosthodontics and Dental Materials, Policlinico “Le Scotte”, Viale Bracci, Siena, 53100, Italy.  E-mail: md3972@mclink.it

 

 

Research Article

A 24-month randomized clinical trial of a two- and three-step

etch-and-rinse technique

 

Alessandra Reis, dds, phd,   Diego  MÂnica,   Franciele  Ferneda,  Roberto  Amaral, dds, ms,

Rodrigo  Stanislawczuk, dds, ms,   Adriana  Manso, dds, ms,   Ricardo Marins  de  Carvalho, dds, phd & Alessandro D. Loguercio, dds, ms, phd

 

Abstract: Purpose: This 24-month randomized paired tooth clinical study evaluated the performance of All Bond 3 used in the simplified (2-step) and full (3-step) versions. Methods: 33 patients, with at least two similar sized non-carious cervical lesions participated in this study. A total of 66 restorations were placed, half using the 2-step All Bond 3 (AB3-2) and the other half using 3-step All Bond 3 (AB3-3). The restorations were placed incrementally using the composite resin Aelite. The restorations were evaluated at baseline and after 6, 12 and 24 months following the modified USPHS criteria. Statistical differences between the adhesive were tested using with McNemar’s test and clinical performance over time for each material with the Fisher’s exact test (α= 0.05). Results: After 24 months, six AB3-2 and four AB3-3 were rated as bravo for marginal discoloration but did not differ from each other significantly (P> 0.05). The retention rates at 24 months of AB3-2 and AB3-3 were 90.9% and 97.0%, respectively (P> 0.05). (Am J Dent 2010;23:231-236).

 

 

Address: Dr. Alessandra Reis, Rua 7 de setembro 125 – apto 41, Ponta Grossa, Paraná 84010-350 – Brazil. E-mail: reis_ale@hotmail.com

    

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