June 2011

Influence of five home whitening gels and a remineralizing gel on the enamel and dentin ultrastructure and hardness

 Helena  Burlamaqui  Pinheiro, dds, ms  &  Paulo  Eduardo  Capel  Cardoso,

dds, ms, phd

 

Abstract: Purpose: To investigate the influence of calcium phosphate enhanced home whitening agents on human enamel and dentin surface microhardness and ultramorphology. Methods: Five intact molars crowns were used for ultrastructural analysis and five for microhardness test. Each resulting coronal structure was cut in slices. After measuring baseline Knoop Hardness Number (KHN) of the enamel and dentin, the slices were divided into six experimental groups and one control (n= 5). G1= 15% carbamide peroxide (CP); G2= 16% CP; G3= Ca and PO₄ (remineralizing agent); G4= 16% CP with Ca and PO₄; G5= 7.5% hydrogen peroxide (HP) with Ca and PO₄; G6=7.5% HP with Ca. After each daily session of treatment, specimens were stored in distilled water (37ºC) until the next session. Products were applied for 2 weeks, according to manufacturers' instructions. Additional KHN were determined. Results: Conventional whitening agents (G1; G2) and the gel with Ca (G6), caused KHN decrease (P< 0.05). The remineralizing and whitening agents with Ca and PO₄ (G3; G4; G5) did not change KHN. A change of morphology was observed on enamel and dentin surfaces in G1; G2; G5. (Am J Dent 2011;24:131-137).

 

 

Address: Prof. Paulo Eduardo Capel Cardoso, Department of Biomaterials, Dental School, University of São Paulo, Av. Prof. Lineu Prestes, 2227 – Cidade Universitária – CEP 05508-000 São Paulo/SP, Brazil.  E-mail: paulocapel@usp.br

 

 

Effects of polishing on surface roughness, gloss and color of surface reaction type pre-reacted glass-ionomer filled resin composite

 Yumiko Hosoya, dds, phd,  Takanobu Shiraishi, meng, phd,  Tetsuro Odatsu, dds, phd,  Masashi Miyazaki, dds, phd &  Franklin GarcÍa-Godoy, dds, ms

 

Abstract: Purpose: To evaluate the effects of polishing on surface roughness, gloss and color of different shades of surface reaction type pre-reacted glass-ionomer (S-PRG) filled nano-hybrid resin composite. Methods: Resin disks of 15 mm diameter and 2 mm thickness and final polish with 1000-grit SiC paper, super fine cut diamond (FG) point, silicon (MFR) point and Super-Snap mini-disk red (SNAP) were made with Beautifil II shades: A2, A2O, Inc). One week after curing, the surface roughness, gloss and color were measured. Data was analyzed with ANOVA and Fisher’s PLSD with α= 0.05 Results: For all shades, the order of roughness (Ra) ranked according to groups of 1000-grit SiC > FG > MFR > SNAP with significant differences among all groups. For all shades, the order of gloss ranked according to groups of SNAP > MFR > FG > 1000-grit SiC with significant differences among the groups except for between MFR and FG without significant difference. The influence of the surface roughness on color differed among the polishing groups and shades. However, the values of the color differences (DE*ab) between the polishing groups of all shades were imperceptible to the naked eye. (Am J Dent 2011;24:138-142).

 

 

Address: Dr. Yumiko Hosoya, Department of Pediatric Dentistry, Course of Medical and Dental Science, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1, Sakamoto, Nagasaki 852-8588, Japan.  E-mail: hosoya@nagasaki-u.ac.jp

 

 

 

 

Comparative clinical study of coronally advanced flap with and without use of plasma rich in growth factors in the treatment of gingival recession

Ardeshir Lafzi, dds, msc, Mohammad Taghi Chitsazi, dds, msc, Ramin Mostofi Zadeh Farahani, dds & Masoumeh Faramarzi, dds, msc

 

Abstract: Purpose: To evaluate the clinical efficiency of the coronally advanced flap (CAF) with and without plasma rich in growth factors (PRGF) in the management of gingival recession defects. Methods: 20 bilateral similar recession defects in six healthy non-smoker subjects were included in the present study. The test sites received PRGF as an adjunct to the coronally advanced flap (CAF) while the control sites were treated with CAF only. The clinical parameters including recession depth (RD), percentage of root coverage (RC), recession width (RW), mucogingival junction position (MGJ), width of keratinized tissue (WKT), clinical attachment level (CAL), and probing depth (PD) were measured at the baseline, 1, and 3 months post-operatively. The data were analyzed using Wilcoxon signed rank and Mann-Whitney U tests. Results: After 3 months, the mean root coverage was 43 ± 34.9% in the CAF group and 61 ± 23.5%) in the CAF + PRGF. Both treatment protocols led to a significant improvement in all measured variables compared to the baseline values, except the width of keratinized tissue. While PRGF enhanced the outcomes of CAF especially throughout the first month post-operatively, it offered no clinical advantage over CAF alone during the subsequent 2 months. (Am J Dent 2011;24:143-147).

 

 

Address: Dr. Ramin Mostofi Zadeh Farahani, School of Dentistry, Tabriz University of Medical Sciences, Goulash St., Daneshgah St., Tabriz, Iran. E-mail: r.mostofi@gmail.com

 

 

Occlusion of dentin tubules with antibacterial ammonium hexafluorosilicate solution for the prevention of dentin caries

 Shingo  Shibata, dds,  Toshiyuki  Suge, dds, phd,  Kunio  Ishikawa, phd  &  Takashi  Matsuo, dds, phd

 

Abstract: Purpose: To evaluate the degree of penetration of an ammonium hexafluorosilicate [SiF: (NH₄)₂SiF₆] solution containing various antibacterial agents into dentin and the depth of dentin tubule occlusion by the precipitate. Methods: Various antibacterial SiF solutions were prepared with the addition to chlorhexidine (CHX), cetylpyridinium chloride (CPC), isopropyl methylphenol (IPMP), or epigallocatechin gallate (EGCG), respectively. Two types of dentin disks were prepared from extracted teeth. One was a dentin surface covered with a smear layer, and the other treated with EDTA for 2 minutes to remove the smear layer and open dentin tubules. Then, the disks were treated with SiF solution with or without antibacterial agents for 3 minutes. The dentin surface and a longitudinally divided surface were observed with scanning electron microscopy (SEM) immediately after SiF treatment and after immersion in synthetic saliva for 7 days. Results: SEM photographs demonstrated that dentin tubules after treatment with SiF were occluded homogeneously and similar to those on conventional SiF treatment regardless of the addition of an antibacterial agent. However, the depth of occlusion became significantly shallower when SiF was applied to dentin specimens covered with a smear layer. (Am J Dent 2011;24:148-152).

 

 

Address: Dr. Toshiyuki Suge, Department of Conservative Dentistry, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8504, Japan. E-mail:  suge@dent.tokushima-u.ac.jp

 

 

Disinfection of toothbrushes contaminated with Streptococcus mutans

 Kim BÉlanger-GiguÈre, Steeve GiguÈre, dvm, phd  & Myriam BÉlanger, msc, phd

 

Abstract: Purpose: To determine the most effective method to kill Streptococcus mutans on contaminated toothbrushes. Methods: Seven toothbrushes (one for each treatment and the control) were contaminated with S. mutans. Toothbrushes were then rinsed in phosphate buffered saline (PBS) and treated as follows: (1) control without treatment; (2) air dry for 4 hours; (3) Crest Pro-Health mouthwash for 20 minutes; (4) Listerine mouthwash for 20 minutes; (5) normal cleaning cycle in a dishwasher; (6) microwave on high power for 5 minutes; and (7) ultraviolet light using the DenTek Toothbrush Sanitizer for 10 minutes. All toothbrushes were rinsed again with PBS. The bristles were cut and vortexed in PBS. Serial dilutions were performed and the number of colonies enumerated after incubation. The experiment was independently repeated seven times. Results: The Crest Pro-Health mouthwash and the dishwasher almost completely eliminated S. mutans. The second most effective treatment was the microwave. The Listerine mouthwash and the air dry groups were not significantly different from each other and ranked third. Although UV light significantly decreased the number of bacteria compared to the control, reduction in the number of S. mutans CFU was significantly lower than that of all the other treatments evaluated. Crest Pro-Health mouthwash for 20 minutes and a normal dishwasher cycle are the most effective methods to eradicate S. mutans from contaminated toothbrushes. (Am J Dent 2011;24:155-158).

 

 

Address: Dr. Myriam Bélanger, University of Georgia, Department of Infectious Diseases and Georgia Genomics Facility, 110 Riverbend Road, Athens, GA 30622, USA.  E-mail: belanger@uga.edu

 

 

 

 

Bonding ability of three ethanol-based adhesives after thermal fatigue

 Jorge  PerdigÃo, dmd, ms, phd,  George  Gomes, dmd  &  Ana  Sezinando, dmd, ms

 

Abstract: Purpose: To study the effect of thermal fatigue on the μTBS and interfacial morphology of three ethanol-based etch-&-rinse 2-bottle adhesives. Methods: μTBS - 24 third molars were randomly assigned to one of three adhesive systems: (1) Adper Single Bond Plus (SBP, 3M ESPE); (2) Ambar (AMB, FGM); (3) Excite (EXC, Ivoclar Vivadent), and restored with a hybrid resin composite. For each adhesive, half of the specimens were thermocycled (TC) for 20,000 cycles (5-55°C) while the other half was kept in distilled water for 24 hours at 37°C (control). Specimens were sectioned in X and Y directions and the resulting sticks were tested to failure in tension mode at a crosshead speed of 1 mm/minute. Statistical analysis was computed using ANOVA and Tukey's post hoc for the μTBS; and non-parametric cross-tabulation with Chi-Square for the pre-testing failures at P< 0.05. Interfacial morphology - The occlusal enamel was removed from 12 extracted molars perpendicular to the long axis of the tooth. Teeth were equally assigned to one of the three adhesives and restored with a 1 mm-thick layer of a hybrid composite resin. A 2 mm-thick disk was sectioned from each specimen and cross-sectioned in two identical halves. Half of the each specimen was TC for 20,000 cycles (5-55°C) while the other half was kept in distilled water for 24 hours at 37°C (control). Specimens were chemically challenged and prepared for FESEM observation to observe the integrity of the hybrid layer before and after thermal fatigue. Micrographs were recorded digitally at standard magnifications and measurements were taken with the microscope embedded image software. Results: μTBS - SBP and AMB resulted in statistically similar mean μTBS regardless of thermal fatigue. EXC resulted in statistically lower mean μTBS than SBP and AMB for the control (P< 0.001) and for the TC specimens (P< 0.0001). Interfacial morphology - The hybrid layers of SBP and AMB were densely infiltrated without interfacial failure. For EXC, extensive areas of debonding were observed between the adhesive layer and the hybrid layer both for the control and the TC groups. Thermal fatigue did not influence the bonding ability of AMB and SBP, but was detrimental for EXC. (Am J Dent 2011;24:159-164).

 

 

 

 

Address: Dr. Jorge Perdigão, Department of Restorative Sciences, University of Minnesota, 515 SE Delaware St, 8-450 Moos Tower, Minneapolis, MN 55455, USA.  E-mail: perdi001@umn.edu

 

 

 

Effect of potential remineralizing agents on acid softened enamel

 Cecilia P. Turssi, dds, ms, phd,  Fernando A. Maeda, dds, ms,  Danielle C. F. Messias, dds, ms, phd, Francisco C. Rehder Neto, dds, ms, MÔnica C. Serra, dds, ms, phd  &  Daniel Galafassi, dds, ms

 

Abstract: Purpose: To assess whether pastes containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and calcium sodium phosphosilicate (CSP) protect acid softened enamel against further erosive episodes. Methods: Enamel slabs of bovine teeth with preformed erosion-like lesions were randomly assigned to five treatment groups (n = 15): A) CPP-ACP (MI Paste, GC America); B) CPP-ACP+Fluoride (CPP-ACP+F, MI Plus Paste, GC America); C) CSP (Tooth Revitalizing Paste, Oravive); D) fluoridated dentifrice (FD, Sensodyne Cool Gel, GSK); E) control (CO, unexposed to any product). Paste treatments (1:3 slurry in deionized water or undiluted product in the case of the CPP-ACP formulae) were performed between five cycles of alternating erosive challenge (0.3% citric acid, pH = 3.2) and remineralization in artificial saliva. Specimens were analyzed by Knoop surface microhardness (SMH). Results: ANOVA indicated a significant (P< 0.0001) difference among the SMH values attained by acid softened enamel following the exposure to the pastes interspersed with erosion-remineralization cycles. Tukey’s test ascertained that SMH values observed for the CPP-ACP+F and CSP groups did not differ from that of FD group, which were significantly higher than that found for the CO group. Specimens treated with CPP-ACP did not differ from any of the other groups. (Am J Dent 2011;24:165-168).

 

 

 

 

Address: Dr. Cecilia P. Turssi, Instituto e Centro de Pesquisas São Leopoldo Mandic, Laboratório de Ensaio de Materiais, R. Dr. José Rocha Junqueira, 13 CEP 13045-755, Campinas SP Brazil. E-mail: cecilia.turssi@gmail.com

 

 

Calcium phosphate-based solutions promote dentin tubule occlusions less susceptible to acid dissolution

 Haijing Gu, dds, ms, phd,  Junqi Ling, dds, phd,  John P. LeGeros, phd   &   Racquel Z. LeGeros, phd

 

Abstract: Purpose: To determine the efficacy supersaturated calcium phosphate (CaP) solutions containing fluoride (F) and zinc (Zn) ions in occluding dentin tubules with precipitates less susceptible to acid dissolution and to compare the performance of these solutions with the oxalate solutions containing calcium (Ca) or phosphate (P) ions. Methods: Dentin sections from human molars divided into groups: Group A – control (treated with double distilled H₂O), Groups A1, A2 and A3 were treated with experimental solutions supersaturated with respect to F and Zn-substituted calcium phosphates. Solutions A1 and A2 were similar in composition but differed in pH values (A1, pH 7; A2, pH 5.5). Solutions A2 and A3 were similar in pH (pH 5.5) but the A3 solution had twice the concentrations of F and Zn²⁺ ions compared to A2. Another group of dentin sections were treated with A3 solution, oxalate solution containing Ca (OX/Ca) and OX solution containing P (OX/P). The control and treated dentin sections were characterized using scanning electron microscopy. Results: All treated dentin sections showed occluded dentin tubules; with the group A3 showing the highest percent of occluded dentin tubules. The precipitates in the dentin tubules treated with A3 remained while those treated with OX/Ca or OX/P dissolved after exposure to an acidic buffer. (Am J Dent 2011;24:169-175).

 

 

Address: Dr. J. Ling, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, 56 Ling Yuan Xi Road, Guangzhou 510055, China.  E-mail: Lingjq@mail.sysu.edu.cn  mail: Dr. R.Z. LeGeros, Department of Biomaterials & Biomimetics, New York University College of Dentistry, NY 10010, USA.  E-mail: rzl1@nyu.edu

 

 

Influence of tooth preparation burs on the roughness and bond strength of adhesives to human dentin surfaces

 Mohamed F. Ayad, bds, mscd, phd, Abdulhamaid A. Maghrabi, bds, ms, phd, Ragab E. Saif, bds, msc, phd &  Franklin GarcÍa-Godoy, dds, ms

 

Abstract: Purpose: To characterize the surface roughness of human dentin prepared with different rotary instruments and its influence on the micro-tensile bond strength (µTBS) of self-etch adhesives. Methods: Dentin surfaces were created from mid-coronal sound dentin in extracted, human third molars. The teeth were ground with high-speed diamond, tungsten carbide finishing, and cross-cut carbide rotary instruments. Morphological changes obtained were investigated with a surface texture analyzer. Two additional specimens from each group were treated and prepared for scanning electron microscopy. Resin composite (Z100) was bonded to the surfaces using Optibond FL (control), Adper Prompt L-Pop (strong), Clearfil SE Bond (mild), or Clearfil S3 Bond (ultra-mild). Rectangular micro-specimens were prepared using the slow-speed diamond saw and tested in tensile to determine the µTBS. The data were analyzed with one-way analysis of variance and Tukey’s HSD test (α= 0.05). Results: Surface preparation resulted in significant differences for surface topography and micro-tensile bond strength (P< 0.001). The cross-cut carbide burs had significantly higher mean roughness readings (SD) for all parameters: Ra [8.6 (1.9) µm], Rq [10.9 (2.2) µm], and Ry [41.1 (2.1) µm], except for the mean Rz [12.1 (3.1) µm] value, which was recorded for diamonds. The other roughness parameters for the diamond rotary instruments were intermediate. Dentin surfaces completed with tungsten carbide finishing burs produced a smoother surface Ra [1.2 (0.5) µm)] Rq ([1.6 (0.6) µm], Ry [6.4 (2.6) µm)] and Rz [1.9 (0.6) µm)]. The etch-and-rinse adhesive (OptiBond FL) yielded high micro-tensile values (58.1-68.3 MPa), irrespective of the rotary instruments used. The micro-tensile bond strength values were comparable for self-etch adhesives (Adper Prompt L-Pop, Clearfil SE Bond, Clearfil S3 Bond) irrespective of the burs used. The µTBS values were significantly higher with tungsten carbide finishing burs and smooth dentin surfaces. (Am J Dent 2011;24:176-182).

 

 

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

 

 

Research Article

The whole is greater than the sum of its parts: Dental plaque bacterial interactions can affect the virulence properties of cariogenic Streptococcus mutans

Howard K. Kuramitsu, phd  &  Bing-Yan Wang, dds, phd

 

Abstract: It has been well established that dental caries results from the accumulation of dental plaque on tooth surfaces. Several decades of in vitro and as well as clinical studies have identified Streptococcus mutans as an important etiological agent in carious lesion formation. In addition, a variety of approaches have suggested that interactions between the bacterial components of biofilms can influence the properties of such polymicrobial structures. Therefore, it is likely that the mere presence of S. mutans in dental plaque does not alone account for the cariogenic potential of such biofilms. Recent studies have indicated that several bacteria commonly found in dental plaque can influence either the viability and/or virulence properties of S. mutans. This review will summarize some of the more recent findings in this regard as well as their implications for the development of novel anti-caries strategies. (Am J Dent 2011;24:153-154).

 

 

Address: Dr. Howard Kuramitsu, 8518 Cahill Drive, Unit 51, Austin, TX 78729, USA. E-mail:  kuramitsu@earthlink.net

 

 

Noncarious cervical lesions (NCCL) – A clinical concept based on the literature review. Part 2: Restoration

Raluca Pecie, dr, Ivo Krejci, prof dr med dent, Franklin GarcÍa-Godoy, dds, ms  &  Tissiana Bortolotto, dr, phd

 

Abstract: Purpose: To present an updated knowledge on the restorative options and their performance in the particular environment of non-carious cervical lesions (NCCL). Methods: Evidence-based support for a proper restoration of NCCL was searched. For this purpose, literature over the last 10 years available in the MEDLINE database was reviewed. Previous systematic reviews, meta-analysis and clinical trials as randomized clinical trials with a testing period of minimum 1 year were selected. Results: Until recently, glass-ionomer-based materials were considered the treatment of choice in most of the NCCL, although consistent improvements are still required. Today, based on the excellent esthetic properties and the good clinical performance, there is a general indication to use composite in NCCL. Clinical behavior was found to be highly product-dependent. The choice of an adhesive with tested efficiency is decisive for the retention and marginal adaptation, whereas differences in flexibility were not found to be clinically important. A periodontal-esthetic approach was suggested by combining the surgical root coverage with the correction of the emergence profile by composite. (Am J Dent 2011;24:183-192).

 

 

Address: Dr. Raluca Pecie, Division of Cariology and Endodontology, University of Geneva, Rue Barthélemy-Menn 19, CH-1205 Geneva, Switzerland.  E-mail: raluca.pecie@unige.ch

 

 

2011: February, April, June, July Sp. Issue, August, October, December

2010: February, April, May Sp. Issue, June, August, October, December

2009: February, March Sp Issue, April, June, August, October, December

2008: February, April, June, August, October, December

2007: February, April, June, August, September Sp. Issue, October, December

2006: February, April, June, August, October, December

2005: February, April, June, July Sp. Issue, August, October, December

2004: February, April, June, August, October, December

1988-2003: Coming soon