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Perspective and Call for Action

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The global increase in dental caries. A pending public health crisis

Robert A. Bagramian,  dds, mph, phd,  Franklin Garcia-Godoy, dds, ms Anthony R. Volpe, dds, ms

Abstract: A current review of the available epidemiology data from many countries clearly indicates that there is a marked increase in the prevalence of dental caries. This global increase in dental caries prevalence affects children as well as adults, deciduous as well as permanent teeth, and coronal as well as root surfaces. This prevalence increase in dental caries clearly signals a pending public health crisis. Although there are differences of opinion regarding the cause of this global dental caries increase, the remedy is well known: a return to the public health strategies that were so successful in the past, a renewed campaign for water fluoridation, topical fluoride application and the use of fluoride rinses, a return to school oral health educational programs, and an emphasis on proper tooth brushing with a fluoride dentifrice, as well as flossing and a proper diet and regular dental office visits. If these remedies are not initiated, there could be a serious negative impact upon the future oral health (and systemic health) of the global community, as well as a strain on the dental profession and a major increase in the cost of dental services. (Am J Dent 2009;22:3-8).

Address: Dr. Robert A. Bagramian, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA. E-mail: robtbagr@umich.edu

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Research Article

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Fracture strength of endodontically treated molars transfixed horizontally by a fiber glass post

Maria Cecilia Gomes Beltrao, dds, ms, phd, Ana Maria Spohr, dds, ms, phd, HugO Mitsuo Silva Oshima, ms, phd, Eduardo Goncalves Mota, dds, ms, phd, & Luiz henrique burnett jr., dds, ms, phd

Abstract: Purpose: To assess the effect of a horizontally transfixed fiber glass post placed between buccal and palatal surfaces, on the fracture strength of endodontically treated molar teeth with MOD cavities, either restored with resin-based composite, or not. Methods: 75 sound maxillary human third molars were extracted, embedded in acrylic resin blocks and randomly assigned to five groups (n=15). Group A (sound teeth), (control) and Groups B, C, D and E, which were subjected to the following procedures after endodontic treatment: GB – (MOD+Endo), GC – (MOD+Endo+Post), GD – MOD and composite restoration (MOD+Endo+CR), GE – (MOD+Endo+Post+CR). The specimens were stored in distilled water at 37ºC for 24 hours. Later, a compressive force was applied by means of a universal testing machine at 1 mm/minute speed, parallel to the long axis of the teeth until fracture occurred. Results: The means of the results (N) followed by the same letter represent no statistical difference by ANOVA and Tukey (P< 0.05): GA = 4289.8 (± 1128.9)a, GB = 549.6 (± 120.7)b, GC = 1474.8 (± 338.1) c, GD = 1224.7 (± 236.0)c, GE = 2645.4 (± 675.1)d. In the analysis of qualitative variables, there was a tendency to cusp fracture in all groups except for Group C. The fiber glass post transfixed horizontally in a MOD cavity significantly increased the fracture resistance of the teeth restored with resin composite. (Am J Dent 2009;22:9-13).

Address: Dr. Luiz Henrique Burnett Jr., Pontificia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6681, prédio 6, Faculdade de Odontologia, 90619-900 - Porto Alegre, Rio Grande do Sul, Brazil. E-mail: burnett@pucrs.br

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Research Article

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Efficacy of calcium hydroxide, Er:YAG laser or gaseous ozone against

Enterococcus faecalis in root canals

Jörn Noetzel, dr med dent, Jörg  Nonhoff, dr med dent,  Kerstin  Bitter, dr med dent,  Jutta  Wagner, dr med, Konrad  Neumann, dr rer nat  &  Andrej  M.  Kielbassa, prof, dr med dent

Abstract: Purpose: To evaluate the efficacy of Ca(OH)₂, Er:YAG laser or gaseous ozone (either alone or combined with instrumentation and various irrigants) against Enterococcus faecalis in root canals. Methods: 180 extracted, human, single-rooted teeth were divided into four groups of 45 teeth each. In Group 1 root canal enlargement up to ISO-size 60 (MAF) was performed, whereas only initial shaping (MAF ISO-size 40) was carried out in Groups 2 to 4. After sterilization all teeth were inoculated with E. faecalis and incubated for 3 days, followed by evaluation of CFU. Subsequently, root canal enlargement up to ISO-size 60 was performed in Groups 2 to 4 using NaCl solution (0.9%) in Group 2, NaOCl (1%) in Group 3 and CHX (0.2%) in Group 4. Finally, each group of 45 teeth was subdivided into three groups (n= 15 each) either applying Ca(OH)₂ for 7 days, using Er:YAG laser radiation for 30 seconds or gaseous ozone for 120 seconds, followed by final evaluation of CFU. Results: Both in Groups 1 and 2 the median reduction of bacteria after application of Ca(OH)₂ (factor 10⁴ each) and ozone (in Group 1: factor 5 x 10³; in Group 2: factor 5 x 10⁴), respectively, was significantly higher than after Er:YAG laser treatment (factor 10² each, Mann-Whitney test). The antibacterial efficacy was significantly increased by the additional use of NaOCl or CHX as irrigants in all subgroups (Groups 3 and 4) compared to corresponding subgroups of Group 1 (Mann-Whitney test). (Am J Dent 2009;22:14-18).

*: Dr. Jörn Noetzel, Department of Operative Dentistry and Periodontology, University School of Dental Medicine, Charité - Universitätsmedizin Berlin, Aßmannshauser Str. 4-6, 14197 Berlin, Germany. E-*: joern.noetzel@charite.de

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Research Article

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Spectrophotometric evaluation of color match to VITA classical shade

guide of four different veneering porcelain systems for metal ceramic

restorations

Giovanni Fazi, dds, ms, Alessandro Vichi, dds, phd, Gabriele Corciolani, dds, ms  &  Marco Ferrari, md, dds, phd

Abstract: Purpose: To determine by a spectrophotometric analysis the variations in color between the fabricated shade of four different porcelain systems and the intended shade when applied in a set thickness. Methods: Four porcelain systems (Duceram Kiss, VITA Omega, Wieland Reflex, Ivoclar IPS d.SIGN) for metal ceramic restorations were selected. Three disk-shaped (15 mm diameter, 0.3 mm thickness) specimens per group were made for three different shades of the A color scale of the Vitapan classical shade guide. On a Cr-Co alloy, 0.15 mm of porcelain opaque and 1.0 mm of translucent porcelain was applied. The porcelain stratification was executed according to the manufacturers’ indications. The color measures were made by the clinical spectrophotometer Easyshade. Results: No statistically significant differences were found among the ceramic systems examined. The recorded differences in color between A2 porcelain disks and corresponding VITA shade tabs were closer (mean ΔE = 2.50) than those recorded for shade A3 (mean ΔE = 3.84) and shade A3.5 (mean ΔE= 3.94) (P< 0.05). (Am J Dent 2009;22:19-22).

*: Dr. Giovanni Fazi, Via A. Lamarmora 22, 50121 Florence, Italy.  E-*: fazi_90211@yahoo.com

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                                                                                                                                                                                           Research Article

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Whitening effect and morphological evaluation of hydroxyapatite materials

Alp  Dabanoglu, dr med dent,  Claudia  Wood, dr PhD,  Franklin  García-Godoy, dds, ms

&  Karl-Heinz  Kunzelmann, dr med dent

Abstract: Purpose: To measure the efficacy of the whitening effect of non-oxidizing and non-acidic nano- and micro-hydroxyapatite materials on the enamel surface and to evaluate the surface changes after treatment. Methods: Three hydroxyapatite suspensions and two hydroxyapatite mixtures in dissolvable polymer films were applied to a total of 30 extracted caries-free human premolars. After the last material application, a hydrodynamic shear force was generated and applied for 2 minutes to all teeth to simulate mechanical loading of the surface. The tooth color was measured with a dental spectrophotometer. The mean changes of the L*a*b* values between different measurements in each group were expressed as ΔE and were analyzed with ANOVA and the Tukey's post-hoc test. Results: The groups of the nano-hydroxyapatite, the hydroxyapatite-nanocrystals and the tricalcium-phosphate exhibited significant ΔE values between baseline and after hydrodynamic shear force application (P< 0.05). In conclusion, the materials used in the study are very promising alternatives to oxidizing bleaching agents. (Am J Dent 2009;22:23-29).

*: Prof. Dr. Karl-Heinz Kunzelmann, Ludwig Maximilians University, Faculty of Dentistry, Department of Operative Dentistry, Goethe Str. 70, D-80336 Munich, Germany.  E-*: karl-heinz@kunzelmann.de

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Research Article

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Effects of acidic primer/adhesives on primary and permanent dentin

Ana FlÁvia Sanches Borges, dds, ms, phd,  Regina Maria Puppin-Rontani, dds, ms, phd,

Renata Andrade Bittar, dds, ms,  Kamila Rosamilia Kantowitz, dds, ms, Fernanda Miori Pascon, dds, ms  &  Airton Abrahão Martin, ms, phd

Abstract: Purpose: To evaluate the quality of primary and permanent dentin by Fourier transformed Raman spectroscopy (FT-Raman), and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS). Methods: The middle dentin of crowns was reached by carbide bur abrading providing a uniform smear layer. Self-etching primers were applied in order to simulate the etching of self-etching adhesive systems. The groups were (n = 6): G1 (primary dentin smear layer); G2 (primary dentin etched by primer of Clearfil Protect Bond); G3 (primary dentin etched by Adper Prompt); G4 (permanent dentin smear layer); G5 (permanent dentin etched by primer of Clearfil Protect Bond); G6 (permanent dentin etched by Adper Prompt). SEM/EDS were made in order to obtain additional elemental data to complement FT-Raman. FT-Raman data were submitted to cluster analysis. Results: Overall, FT-Raman showed differences between primary and permanent dentin concerning organic content, but not for inorganic content. FT-Raman showed differences in the organic content between primary and permanent dentin after self-etching primer use. HEMA usage caused molecular changes in the organic content, while phosphoric acidic ester caused molecular changes in the inorganic content of primary and permanent dentin. The SEM/EDS identified C, O, P, and Ca, which could not replace ions to change mineral molecular arrangement. Both organic and mineral content arrangements were similar after self-etching primers action. The organic content of dentin was modified by both Clearfil PB primer and Adper Prompt for primary dentin but only by Clearfil PB for permanent dentin. The inorganic content of primary middle dentin was similar to the inorganic content of permanent middle dentin, even when Adper Prompt is used. (Am J Dent 2009;22:30-36).

*: Dr. Regina Maria Puppin-Rontani, Av. Limeira, 901, Areião, CEP: 13.414-903 – Piracicaba (SP), Brazil.  E-*: rmpuppin@fop.unicamp.br

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Research Article

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Effect of acid etching time on the degradation of resin-dentin bonds

in primary teeth

Mariane Emi Sanabe, dds, ms, Kamila Rosamiglia Kantovitz, dds, ms,

Carlos Alberto de Souza Costa, dds, ms, phd &  Josimeri Hebling, dds, ms, phd

Abstract: Purpose: To investigate the influence of etching time on the degradation of resin-dentin bonds produced in primary teeth. Methods: 40 primary molars were randomly divided into four groups according to the adhesive system, Single Bond (SB) and Clearfil SE Bond (CSEB), and acid etching time. SB was applied to dentin after phosphoric acid etching for 15 or 7 seconds, whereas CSEB was applied after the application of SE Primer for 20 or 10 seconds. Resin composite crowns were built-up followed by the production of specimens with a cross-sectional area of 0.49 mm², which were further divided according to the storage condition, 24 hours, 6 and 12 months in water. Data were submitted to ANOVA and Tukey tests (α=0.05). Results: After 24 hours there was no significant difference between bond strengths produced by the adhesive systems, irrespective of the acid etching time. Water storage for 6 and 12 months significantly reduced bond strengths of SB, especially when the dentin was acid etched for 15 seconds. For CSEB, no significant alteration in bond strength was seen up to the storage period of 12 months for both etching times. (Am J Dent 2009;22:37-42).

*: Dr. Josimeri Hebling, São Paulo State University - UNESP, Araraquara School of Dentistry, Rua Humaitá, 1680 Araraquara, São Paulo 14801-903, Brazil.  E-*: jhebling@foar.unesp.br

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Research Article

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Influence of curing mode intensities on cell culture cytotoxicity/genotoxicity

Alena  Knezevic, dds, phd,  Davor  Zeljezic, phd,  Nevenka  Kopjar, phd  &  Zrinka  Tarle, dds, phd

Abstract: Purpose: This study determined the cytotoxic/genotoxic effect of different curing modes on cell culture. Methods: A thin layer of lymphocyte cultures was cured applying three different curing modes of Bluephase C8 LED curing unit. Cultures were exposed to light directly or through a layer ( 2 mm ) of polymerized resin composite sample. Cells were analyzed using trypan blue exclusion test, acridine orange/ethidium bromide dyeing technique, and alkaline comet assay. Results: Only low intensity mode after direct exposure significantly increased the number of nonviable lymphocytes detected using trypan blue. All curing procedures significantly increased the number of apoptotic lymphocytes regardless whether the exposure occurred directly or through the composite. Low intensity mode in direct exposure significantly elevated DNA migration compared to other curing modes. 1 hour after exposure significant increase in tail length and intensity for all modes and procedures was detected. However, DNA damage measured for cultures cured by low intensity mode was higher compared to the other two modes; thus, despite of curing light intensity, longer curing time leads to greater cytotoxicity/genotoxicity in cell culture. (Am J Dent 2009;22:43-48).

*: Dr. Alena Knezevic, Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb , Gunduliceva 5, 10000 Zagreb , Croatia .  E-*: ma505ak@yahoo.com

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Research Article

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Association between staining by caries detector dye

and the corresponding mineral density in dentin caries

Miho  Sunago, dds,  Syozi  Nakashima, phd  &  Junji  Tagami, dds, phd

Abstract: Purpose: To examine an association between coloration (red, pink) resulting from staining with Caries Detector Dye (CDD) and the corresponding mineral density in dentin caries lesions determined by transverse microradiography (TMR). Methods: CDD coloration of the lesion sections (approx. 190μm) prepared from extracted caries teeth was photographed, and the corresponding relative mineral densities (RMD: relative values to the sound dentin) were obtained by TMR. A parallel study was performed using artificially demineralized and then remineralized dentin lesions. Results: The mean RMD values in the naturally black-pigmented, red- and pink-stained portions were 46 ± 26.7%, 64 ± 24.5%, and 80 ± 15.1%, respectively. There were statistical differences in the RMD values among the three portions, as well as a wider range of RMD value distributions in the red and black-pigmented portions than in the pink portion. Even among the black-pigmented and red portions, much higher RMD values more than 90% were observed in several lesions, which were close to the mineral density of the sound (unaffected) dentin tissue. On the other hand, the remineralized surface layer of artificially demineralized lesions did not show the red coloration, and there seemed a threshold value of mineral density (approx. 21%), beyond which the red coloration was not observed. Similar threshold value was noted in the remineralized lesion body. This study showed a remarkable discrepancy regarding the RMD value for the red staining behavior between the naturally occurring caries and artificial carious lesion. (Am J Dent 2009;22:49-54).

*: Dr. Miho Sunago, Cariology and Operative Dentistry, Department of Restorative Science, Graduate School , Tokyo Medical and Dental University , 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. E-*: miho_suna@yahoo.co.jp

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Research Article

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IPS Empress inlays luted with a self-adhesive resin cement after 1 year

Michael  Taschner, dmd,  Roland  Frankenberger, dmd, phd,  Franklin  García-Godoy, dds, ms,

Silke  Rosenbusch, dmd,  Anselm  Petschelt, dmd, phd  &  Norbert  Krämer, dmd, phd

Abstract: Purpose: To prospectively compare the clinical performance of two different resin composites for luting IPS Empress inlays and onlays. Methods: 83 IPS Empress restorations were placed in 30 subjects. All restorations were inserted under rubber dam. 43 inlays/onlays were luted with a self-adhesive resin cement [RelyX Unicem (RX)]. A multi-step adhesive (Syntac) was used with Variolink II low viscosity (SV) and served as control (n=40). The restorations were evaluated after 2 weeks: Baseline = 1st recall (R1), after 6 months (R2) and after 1 year (R3) by two calibrated examiners using the modified USPHS criteria. Results: From R1 to R3, one failure was noticed in the SV group (R2) due to marginal enamel chipping. After 1 year of clinical service, SV revealed significantly better results regarding color match and integrity inlay (Mann-Whitney U-test, P< 0.05). No statistically significant differences were observed between SV and RX for the remaining criteria (Mann-Whitney U-test, P>0.05). (Am J Dent 2009;22:55-59).

*: 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-*: frankbg@dent.uni-erlangen.de

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Research Article

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Effect of nanofillers’ size on surface properties after toothbrush abrasion

Larissa  M.  Cavalcante, dds, msc, phd,   Konstantinos  Masouras, bds, msc, phd,  David  C.  Watts, bsc, bds, phd,  Luiz  A.  Pimenta, dds, msc, phd  &  Nick  Silikas, bsc, mphil, phd

Abstract: Purpose: To investigate the effect of filler-particle size of experimental and commercial resin composites, undergoing toothbrush abrasion, on three surface properties: surface roughness (SR), surface gloss (G) and color stability (CS). Methods: Four model (Ivoclar/Vivadent) and one commercial resin composite (Tokuyama) with varying filler-size from 100-1000 nm were examined. Six discs ( 10 mm x 2 mm ) from each product were prepared and mechanically polished. The samples were then submitted to 20,000 brushing strokes in a toothbrush abrasion machine. SR parameters (Ra, Rt and RSm), G, and CS were measured before and after toothbrush abrasion. Changes in SR and G were analyzed by 2-way ANOVA, with Bonferroni post hoc test. CS values were submitted to one-way ANOVA and Bonferroni post hoc test (α= 0.05). Results: Initial G values ranged between 73-87 gloss units (GU) and were reduced after toothbrush abrasion to a range of 8-64 GU. Toothbrush abrasion resulted in significant modifications in SR and G amongst the materials tested, attributed to filler sizes. There was statistically significant difference in color (ΔE* ranged from 0.38-0.88). Filler size did not affect color stability. Toothbrush abrasion resulted in rougher and matte surfaces for all materials tested. Although the individual differences in surface roughness among filler sizes were not always significant, the correlation showed a trend that larger filler sizes resulted in higher surface roughness after abrasion for the SR parameters Ra and Rt (r = 0.95; r = 0.93, respectively). RSm showed an increase after toothbrush abrasion for all resin composites, however no significant correlation was detected (r = 0.21).There was a significant correlation between G and Ra ratios (r = - 0.95). (Am J Dent 2009;22:60-64).

*: Dr. Nick Silikas, Biomaterials Research Group, School of Dentistry, Higher Cambridge Street, M15 6FH, Manchester, United Kingdom.  E-*: nick.silikas@ manchester.ac.uk

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