Research Article

In vitro comparison of three caries dyes

Kazuo  Itoh, dds, phd,  Mizuho  Kusunoki, dds, phd,   Misa  Oikawa, dds,  Chihiro  Tani, dds, phd

&  Hisashi  Hisamitsu, dds, phd

Abstract: Purpose: To evaluate the efficacy of a conventional and newly-developed caries detector (Caries Check) by measuring the Vickers microhardness (VMH) and DIAGNOdent value of the dentin cavity wall of extracted human teeth after removing carious dentin that was stained by the caries detector. Methods: 30 human teeth with coronal dentin caries extending halfway through the dentin were sectioned and extracted for use in this study. As a control, the longitudinal section of a caries-free extracted human tooth was prepared. The VMH and DIAGNOdent values were measured and the microstructure of the dentin cavity wall was examined using a scanning electron microscope (SEM). Results: When Caries Check was employed as a guide for carious dentin removal, the microhardness of the cavity wall was significantly lower than the normal dentin and the DIAGNOdent value indicated that the dentin may have recalcified. SEM observations of the stained regions revealed that Caries Check did not stain the sclerotic dentin. Based on these findings, Caries Check may be a useful modality because the excavation of the dentin structure was shallower and the sclerotic dentin was preserved. (Am J Dent 2009;22:195-199).

Address: Dr. Kazuo Itoh, Department of Clinical Cariology, Showa University, School of Dentistry, 2-1-1 Kitasenzoku, Ohta-Ward, Tokyo 145-8515, Japan. E-mail: kitoh@dent.showa-u.ac.jp

                                                                                                                                        Research Article

Clinical comparison of the plaque removal efficacy of a manual toothbrush

with criss-cross bristle design

Tao  He, dds, phd,  Sarah  Li, bs  &  Lily  Sun, ms

Abstract: Purpose: To compare the plaque removal efficacy of two manual toothbrushes: Oral-B Exceed and Asian Colgate 360° manual toothbrush. Methods: The study used an examiner-blind, two-treatment, randomized, four-period (visits) crossover design. Subjects used each brush twice during the study. At the first visit, 41 subjects who met inclusion criteria and provided informed consent received a baseline plaque examination using the Turesky Modified Quigley-Hein Plaque Index. Subjects then used their assigned toothbrush for 1 minute with a marketed toothpaste without access to a mirror. Brushing was monitored. A post-brushing plaque exam was then performed.  Subjects were rescheduled for their next visit in approximately 3 days. At visits 2, 3 and 4 the same disclosing, brushing and plaque grading procedures were followed. Subjects used their own products at home between visits. Results: 39 subjects presented data for all four study periods; two subjects missed one period each. Baseline plaque scores were balanced between the two groups. Adjusted mean plaque removal (baseline minus post-brushing) scores were 0.479 for the Exceed toothbrush and 0.425 for the Asian Colgate 360° toothbrush (P< 0.002). This translates to 12.7% greater plaque removal for the Exceed toothbrush versus the Asian Colgate 360° toothbrush. No adverse events were reported during the study. (Am J Dent 2009;22:200-202).

Address: Dr. Tao He, P&G Health Care Research Center, 8700 Mason-Montgomery Road, Mason, OH 45040 USA. E-mail: he.t@pg.com

Research Article

In vitro remineralization associated with a bioerodible fluoridated resin

and a fluoride varnish

Royana  Lin, dds,  Travis  Hildebrand, dds  &  Kevin  J.  Donly, dds, ms

Abstract: Purpose: To examine the remineralization effects of a bioerodible fluoridated resin. Methods: 36 extracted permanent molars were suspended into an artificial caries solution to create an artificial caries-like lesion. Teeth were sectioned longitudinally to obtain 100 µm sections containing the artificial caries-like lesion, then photographed with polarized light microscopy in an imbibition media of water, representing a minimum of 5% pore volume. An acid-resistant varnish was applied to the surfaces of the sections, leaving only the natural external tooth surface and caries-like lesion exposed. The external tooth surface of 12 samples had 5% sodium fluoride varnish applied, 12 samples had 5% sodium fluoride bioerodible resin applied, and the remaining samples acted as controls. The sections were returned to the tooth, placed in an artificial saliva solution and brushed daily for 30 days. The sections were removed and photographed under polarized light as before. Using a computerized imaging system, the area of the body of the lesion was measured, comparing the same section before and after the 30-day experimental period to evaluate the remineralization process. Results: The mean percent area remineralization (±SD) was: bioerodible fluoridated resin 44.1 ± 12.1; fluoride varnish 19.1 ± 9.2; control 2.4 ± 3.4. ANOVA indicated a significant variance among groups (P< 0.001). Tukey’s multiple comparison test demonstrated the fluoridated resin to enhance remineralization significantly greater (P< 0.001) than the fluoride varnish and control and the fluoride varnish to enhance remineralization significantly greater (P< 0.002) than the control. (Am J Dent 2009;22:203-205).

Address: Dr. Kevin J. Donly, Department of Pediatric Dentistry, Dental School, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA. E-mail: donly@uthscsa.edu

Research Article

Photoinitiator content in restorative composites: Influence on degree of

conversion, reaction kinetics, volumetric shrinkage and polymerization stress

Carmem  S.  Pfeifer, dds, phd,  Jack  L.  Ferracane, phd,  Ronald  L.  Sakaguchi, dds, ms, phd

&  Roberto  R.  Braga, dds, ms, phd

Abstract: Purpose: To determine the influence of rate of polymerization, degree of conversion and volumetric shrinkage on stress development by varying the amount of photoinitiators in a model composite. Methods: Volumetric shrinkage (with a mercury dilatometer), degree of conversion, maximum rate of reaction (RP_max) (with differential scanning calorimetry) and polymerization stress (with a controlled compliance device) were evaluated. Bis-GMA/TEGDMA (equal mass ratios) were mixed with a tertiary amine (EDMAB) and camphorquinone, respectively, in three concentrations (wt%): high= 0.8/1.6; intermediate= 0.4/0.8 and low= 0.2/0.4. 80 wt% filler was added. Composites were photoactivated (400 mW/cm² x 40 seconds; radiant exposure=16J/cm²). A fourth experimental group was included in which the low concentration formulation was exposed for 80 seconds (32 J/cm²). Results: For the same radiant exposure, conversion, RP_max and stress increased with photoinitiator concentration (P< 0.001). When the low concentration group exposed to 32 J/cm² was compared with the high and intermediate groups (exposed to 16 J/cm²), RP_max still increased with the photoinitiator concentration between all levels (P< 0.001) but conversion and stress did not vary (P> 0.05). Shrinkage did not vary regardless of the photoinitiator concentration or radiant exposure. For the photoinitiator concentrations used in this study. Polymerization stress was influenced by conversion but not by rate of reaction. (Am J Dent 2009;22:206-210).

Address: Dr. Carmem S. Pfeifer, Av. Prof. Lineu Prestes, 2227, São Paulo, SP 05508-000, Brazil. E-mail: pfeifercs@gmail.com

Research Article

Tannerella forsythia detected in infected root canals using nested PCR

Amela  lačević, dds, msc,  lejla  kapur  pojskić, phd,  naida  kadrić  lojo, msc,  jasmin  ramić, bsc

&  kasim bajrović, phd

Abstract: Purpose: This study assessed the occurrence of Tannerella forsythia in patients with acute and chronic primary endodontic infections. Methods: Clinical samples were collected from 40 patients with acute and chronic periradicular disease. Nested polymerase chain reaction (PCR) assay technique was used to detect the presence of T. forsythia in primary endodontic infections. The first round of PCR amplification used universal primers to detect the 16S rDNA sequence. Product from the first round was then used to amplify T. forsythia specific fragment with species-specific pairs of primers. Results: T. forsythia was found in 12 of 27 chronic and 5 of 13 acute infected patients for an overall occurrence frequency of 42.5%. No significant correlation was found between patients with the T. forsythia positive genotype and the occurrence of clinical symptoms in the primary endodontic infections (P< 0.05) (P= 0.496). Also, no significant relationship was found between the occurrence of T. forsythia and the patient’s age (P= 0.61) or gender (P= 0.239). (Am J Dent 2009;22:211-214).

Address: Dr. Amela Lačević, Department of Dental Pathology and Endodontics, School of Dentistry, Bolnička 4a, University of Sarajevo , Bosnia and Herzegovina . E-mail: amelalacevic@yahoo.com

Research Article

Dentin bonding of an etch-and-rinse adhesive using self- and light-cured

composites

Ricardo  Walter, dds, ms,  Edward  J.  Swift, Jr., dmd, ms,  André  V.  Ritter, dds, ms,  Whitley W. Bartholomew &  Christopher  G.  Gibson

Abstract: Purpose: To evaluate the dentin shear bond strength (SBS) of a new two-step etch-and-rinse adhesive system (MPa Direct) using self- and light-cured composites. Methods: The dentin of 160 bovine teeth was ground to 600 grit. Self- (Bisfil 2B) or light-cured (Filtek Supreme Plus) composite was bonded to dentin using MPa Direct, Adper Single Bond Plus, One-Step Plus, OptiBond Solo Plus, or Prime & Bond NT. For the light-cured composite, MPa Direct was used both with and without the HEMA/glutaraldehyde desensitizer (G5) supplied in the kit. For the self-cured composite, OptiBond Solo Plus and Prime & Bond NT were used with and without their respective self-cure acti­vators. Those two adhesives and MPa Direct also were used with the self-cured composite after removal of the oxygen-inhibited layer from the adhesive. Following storage in water for 24 hours, shear bond strengths were determined using a universal testing machine. The data were subjected to factorial ANOVA and Tukey’s test. Results: With the light-cured composite, the mean SBS of MPa Direct was 41.1 MPa. Use of G5 did not significantly affect mean SBS (35.7 MPa). Mean SBS of MPa Direct when used with the self-cured composite was significantly lower (16.6 MPa). How­ever, removal of the oxygen-inhibited layer returned the bond strength (38.9 MPa) to the level obtained using light-cured composite. Both OptiBond Solo Plus and Prime & Bond NT had significantly lower bond strengths when used with the self-cured composite than with the light-cured composite, regardless of whether their self-cure activators were used. Removal of the oxygen-inhibited layer improved the bond strengths of these two adhesives, but the improvement was less than that observed for MPa Direct. Bond strengths of One-Step Plus and Adper Single Bond Plus were not affected by the type of composite resin used. (Am J Dent 2009;22:215-218).

Address: Dr. Rick Walter, Department of Operative Dentistry, University of North Carolina, CB#7450, 433 Brauer Hall, Chapel Hill, NC 27599-7450, USA. E-mail: rick_walter@dentistry.unc.edu

Research Article

Rotating fatigue and flexural strength of direct and indirect

resin-composite restorative materials

Hesam  Mirmohammadi, dds,  Cornelis  J.  Kleverlaan, phd  &   Albert  J.  Feilzer, dds, phd

Abstract: Purpose: To evaluate the flexural strength and rotating fatigue resistance of direct and indirect resin composite restorative materials. Methods: Filtek Z100 and Filtek Z250 (3M ESPE) are direct resin composite restorative materials, and Sinfony (3M ESPE) and Neco (Heraeus Kulzer) are indirect composites. Bar specimens (2 x 2 x 25 mm; n = 10) of these materials were used to determine the flexural strength (F_S) by means of 3-point bending tests according to ISO 4049. The same size specimens (n = 20) were used to prepare hour-glass shaped specimens. Rotating fatigue resistance (RFR) was determined in a rotating-bending cantilever test with the stress located at the constriction of the hour glass. The rotating fatigue resistance tests were conducted according to the staircase approach (10⁴ cycles, 1.0 Hz) and the mean RFR was calculated using logistic regression analysis. Results: F_S ranged between 100.0 and 141.9 MPa and the RFR 51.6 to 89.6 MPa. After 10,000 cycles the strength of the materials decreased between 35 and 48%. RFR of Filtek Z100, Filtek Z250, and Neco (77.4 – 89.6 MPa) were significantly higher than Sinfony (51.6 MPa). (Am J Dent 2009;22:219-222).

Address: Dr. A.J. Feilzer, ACTA, Department of Dental Materials Science, Louwesweg 1, 1066 EA Amsterdam . E-mail: A.Feilzer@acta.nl

Research Article

Effect of bleaching agents on surface free energy parameters of resin composite coated with saliva biofilm

Hatice  Dogan  Buzoglu, dds, phd,  Menemse  Gümüsderelioğlu, msc, phd  &  Ilan  Rotstein, dds

Abstract: Purpose: To assess the effect of 10% carbamide peroxide and 10% hydrogen peroxide bleaching preparations on the surface free energy of resin composite with and without saliva biofilm coating. Methods: 72 light-cured resin com­posite samples were used. The samples were either coated with fresh human saliva or left uncoated. Each sample was placed in a plastic assay tube containing 2 ml of either 10% carbamide peroxide (CP), 10% hydrogen peroxide (HP), or phosphate buffer solution. The tubes containing the composite samples were then placed in a dry incubator at 37°C for 1- and 3-day time intervals. After each time interval the samples were rinsed with distilled water and subjected to wetting measurements using a captive bubble technique. Measurements were taken in triplicate and determination of contact angles done by using film negatives on an enlarger. The differences between pre-treatment and post-treatment measurements and between samples coated with saliva and non-coated samples were analyzed statistically for each time period and treatment group. Results: 10% CP reduced octane contact angle of all exposed composite groups after 1 day of treatment regardless of saliva coating. Differences between the pre-bleached and post-bleached groups were statistically significant only for octane contact angles measured in saliva-coated samples (P< 0.05). 10% CP reduced both the octane and air contact angles of all exposed composite surfaces after 3 days of treatment. The reduction was statistically significant only for octane con­tact angles measured in the saliva-coated samples (P< 0.05). Additionally, 10% CP significantly reduced the surface free energy of saliva-coated samples after 1-day treatment as compared to non-coated samples. 10% HP reduced octane contact angle of all exposed composite groups after 1 day of treatment regardless of saliva coating. The differences between the pre-bleached and post-bleached groups were statistically significant only for octane contact angles measured in the saliva-coated samples (P< 0.05). 10% HP reduced both the octane and air contact angles of all exposed resin composite surface samples after 3 days of treatment regardless of saliva coating. However, the differences between the groups were not statistically significant. (Am J Dent 2009;22:223-227).

Address: Dr. Ilan Rotstein, University of Southern California, School of Dentistry, 925 West 34th Street, Suite 310, Los Angeles, CA 90089-0641, USA. E-mail: ilan@usc.edu

Research Article

Nanohybrid composite vs. fine hybrid composite in extended Class II cavities: Clinical and microscopic results after 2 years

Norbert Krämer, dmd, phd, Christian Reinelt, dmd, Franklin García-Godoy, dds, ms, Michael Taschner, dmd, Anselm Petschelt, dmd, phd  &  Roland Frankenberger, dmd, phd

Abstract: Purpose: To evaluate the clinical behavior of two different resin composites in Class II cavities over a period of 2 years in a controlled prospective split-mouth study. Methods: 30 subjects received 68 direct resin composite restorations (Grandio bonded with Solobond M: n= 36, Tetric Ceram bonded with Syntac: n= 32) by one dentist in a private practice. All restorations were replacement restorations, 24 cavities (35%) revealed no enamel at the bottom of the proximal box, in 33 cavities (48%) the proximal enamel width was < 0.5 mm. The restorations were examined according to modified USPHS criteria at baseline, and after 0.5, 1, and 2 years. At each recall, impressions were taken to prepare replicas. Replicas of 44 selected subjects were assessed for marginal quality under a stereo light microscope (SLM) at x130, and 22 replicas were assessed under a SEM at x200. Results: Both recall rate and survival rate were 100% after 2 years of clinical service. No significant difference was found between the restorative materials (P> 0.05; Mann-Whitney U-test). A significant deterioration was found over time for marginal integrity, tooth integrity, restoration integrity and proximal contact (P< 0.05; Friedman test). SLM and SEM analysis of restoration margins only revealed differences in the amount of detectable perfect margins, in favor of Tetric Ceram (P< 0.05). Both materials performed satisfactorily over the 2-year observation period. (Am J Dent 2009;22:228-234).

Address: Prof. Dr. Roland Frankenberger, Dental Clinic 1 - Operative Dentistry and Periodontology, University Medical Center Erlangen, University of Erlangen-Nuremberg, Glueckstrasse 11, D-91054 Erlangen, Germany. E-mail: frankbg@dent.uni-erlangen.de

Research Article

A randomized, controlled clinical trial of one-step self-etching adhesive

systems in non-carious cervical lesions

Zeyuan  Zhou, dds,  Shuxiang  Yu, dds,  Yong  Jiang, dds,  Yuan  Lin, dds,  Yu  Xiong, dds  &  Longxing  Ni, dds

Abstract: Purpose: To evaluate the clinical effectiveness of two different one-step self-etching adhesives. Methods: Two single-step self-etching adhesive systems, Clearfil Tri-S Bond and G-Bond, were evaluated. As a control, a two-step self-etching adhesive system, Clearfil SE Bond, was used. The teeth to be restored were randomly assigned. The resin composite used to restore the teeth was Clearfil AP-X. The three adhesive systems were evaluated by Modified USPHS at baseline, 3 months, 6 months, and 12 months. The evaluation consisted of retention rate, color match, marginal discoloration (interfacial staining), marginal adaptation (integrity), wear, post-operative sensitivity, caries recurrence, and other failures. Changes over time and across groups were evaluated statistically using generalized estimating equations. Results: During the 12-month study period, no statistical differences were observed among the three groups (P> 0.05) in retention rate, color match, marginal discoloration (interfacial staining), marginal adaptation (integrity). No wear, post-operative sensitivity, caries recurrence, or other failures were detected in any groups. The two one-step self-etching adhesives tested showed good clinical performance at the end of 12 months. (Am J Dent 2009;22:235-240).

Address: Dr. Longxing Ni, Department of Operative Dentistry and Endodontics, School of Stomatology, Fourth Military Medical University , 145 West Changle Road , Xi’an , Shaanxi 710032, P.R. China. E-mail: nilongx@fmmu.edu.cn

Review Article

Saliva: An emerging biofluid for early detection of diseases

Yu-Hsiang Lee, phd  &  David T. Wong, dmd, dmsc

Abstract: The capability to assess physiological states, detect morbidity initiation and progression, and monitor post-treatment therapeutic outcomes through a noninvasive approach is one of the most desirable goals for healthcare research and delivery. Saliva, a multi-constituent oral fluid, has high potential for the surveillance of general health and disease. To reach the above goal through saliva-based diagnostics, two prerequisites must be fulfilled: (1) discovering biomarker(s) for different diseases among the complicated components of saliva, and (2) advancing sensitivity and specificity of biomarker(s) through persistent development of technologies. Under the support and research blueprint initiated by the National Institute of Dental and Craniofacial Research (NIDCR), salivary diagnostics has not only steadily progressed with respect to accuracy and availability, but has also bridged up-to-date nanotechnology to expand the areas of application. With collective efforts over several years, saliva has been demonstrated to be a promising bodily fluid for early detection of diseases, and salivary diagnostics has exhibited tremendous potential in clinical applications. This review presents an overview of the value of saliva as a credible diagnostic tool, the discovery of salivary biomarkers, and the development of salivary diagnostics now and in the future. (Am J Dent 2009;22:241-248).

Address: Dr. David T. Wong, UCLA School of Dentistry and Dental Research Institute, 73-017 CHS 10833 Le Conte Ave., Los Angeles, CA 90095, USA. E-mail: dtww@ucla.edu

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