Malgorzata Klukowska, dds, phd, Hermann GÖtz, dipl-phys, Donald J. White, phd, James Zoladz, asci, BjÖrn-Olaf Schwarz, dr   &  Heinz Duschner, prof dr

Abstract: Purpose: To examine laboratory changes of endogenous non-specific fluorescence and color throughout subsurface of tooth structures prior to and following peroxide bleaching. Methods: Extracted human teeth were cross sectioned and mounted on glass slides. Cross sections were examined for internal color (digital camera) and non-specific fluorescence (µRaman spectroscopy) throughout the tooth structure at specified locations. Surfaces of sections were then saturation bleached for 70 hours with a gel containing 6% hydrogen peroxide. Cross sections were re-examined for color and non-specific fluorescence changes. Results: Unbleached enamel, dentin-enamel junction and dentin exhibit different CIELab color and non-specific fluorescence properties. Bleaching of teeth produced significant changes in color of internal cross sections and substantial reductions of non-specific fluorescence levels within enamel dentin and DEJ.  Enamel and dentin non-specific fluorescence were reduced to common values with bleaching with enamel and the DEJ showing larger reductions than dentin. (Am J Dent 2013; 26:3-9).

Mail: Dr. Donald J. White, Health Care Research Center, The Procter and Gamble Company, 8700 Mason Montgomery Road, Mason, OH 45040, USA. E-mail: white.dj.1@pg.com

Dentin hypersensitivity after teeth bleaching with in-office systems. Randomized clinical trial

Javier Martin, dds, Eduardo Fernandez, dds, Valeria Bahamondes, dds, Andrea Werner, dds, Klaus Elphick, dds, Osmir Batista Oliveira Jr, dds  &  Gustavo Moncada, dds

Abstract: Purpose: To comparatively and prospectively compare in a randomized clinical trial, dentin hypersensitivity after treatment with three in-office bleaching systems, based on hydrogen peroxide at different concentrations, with and without light source activation. Methods: 88 individuals were included according to inclusion and exclusion criteria. Subjects were randomly divided into the following three treatment groups: Group 1 was treated with three 15-minute applications of hydrogen peroxide at 15% with titanium dioxide (Lase Peroxide Lite) that was light-activated (Light Plus Whitening Lase) with five cycles of 1 minute and 30 seconds each cycle, giving a total treatment time of 45 minutes; Group 2 was treated with three 10-minute applications of hydrogen peroxide at 35% (Lase Peroxide Sensy), activated by light (LPWL) same activation cycles than Group 1, with a total treatment time of 30 minutes; Group 3 was treated with only one application for 45 minutes of hydrogen peroxide at 35% (Whitegold Office) without light activation. Each subject underwent one session of bleaching on the anterior teeth according to the manufacturers’ instructions. Dentin sensitivity was recorded with a visual analogue scale (VAS) at baseline, immediately after, and at 7 and 30 days after treatment using a stimulus of an evaporative blowing triple syringe for 3 seconds on the upper central incisors from a distance of 1 cm. A Kruskal-Wallis test followed by Mann-Whitney test was performed for statistical analysis. Results: All groups showed increased sensitivity immediately after treatment. Group 1 displayed less changes relative to baseline with no significant differences (P= 0.104). At 7 and 30 days after treatment, a comparison of VAS values indicated no significant differences between all groups (P= 0.598 and 0.489, respectively). (Am J Dent 2013;26:10-14).

Mail: Dr. Andrea Werner, Operative Dentistry, Department of Restorative Dentistry, School of Dentistry, University of Chile, Sergio Livingston 943, Independencia, Santiago, Chile. E-mail: andrewerner1@yahoo.com

In situ evaluation of a low fluoride concentration gel with sodium trimetaphosphate in enamel remineralization

Marcelle Danelon, ms, Eliana M. Takeshita, phd,  Kikue T. Sassaki, phd  &  Alberto Carlos Botazzo Delbem, phd

Abstract: Purpose: To evaluate the capability of gels with low fluoride (F) concentration and supplemented with sodium trimetaphosphate (TMP) to promote in situ enamel remineralization. Methods: Bovine enamel blocks were selected on the basis of their surface hardness after demineralization, and divided into five groups: gel without F or TMP (placebo); gel with 4,500 ppm F (4,500); gel with 4,500 ppm F + 5% TMP (4,500 5%TMP); gel with 9,000 ppm F (9,000) and gel with 12,300 ppm F (12,300). The study design was blind and cross-over: 12 subjects used palatal devices with four demineralized enamel blocks for 3 days, after topical fluoride application (TFA). Two blocks were removed immediately for analysis of the loosely bound fluoride (CaF₂) and firmly bound fluoride (F) after TFA in enamel. In the remaining blocks, the percentage of surface hardness recovery (%SH), cross-sectional hardness (DKHN) and CaF₂ and F were determined after remineralization. The results were subjected to ANOVA and Bonferroni tests (P< 0.05). Results: The groups 4,500 5%TMP, 9,000, and 12,300 showed the best results with regard to %SH (P< 0.05). Lower DKHN values were observed in the 4,500 5%TMP and 12,300 gel groups (P< 0.05). Higher concentrations of CaF₂ and F were observed in the 12,300 group, followed by the 4,500 5%TMP and 9,000 groups (P> 0.05). It was concluded that it is possible to promote enamel remineralization using gels with low fluoride concentration supplemented with TMP. (Am J Dent 2013;26:15-20).

Mail: Dr. Alberto Carlos Botazzo Delbem, Department of Pediatric Dentistry, Faculty of Dentistry of Araçatuba, Univ. Estadual Paulista (UNESP), Rua José Bonifácio 1193, Araçatuba, SP - CEP 16015-050, Brazil. E-mail: adelbem@ foa.unesp.br, adelbem@pq.cnpq.br

Review Article

The prevalence of tooth hypersensitivity following periodontal therapy with special reference to root scaling. A systematic review of the literature

Miriam E. Draenert, dds, Michael Jakob, dds, Karl-Heinz Kunzelmann, dds, phd  &  Reinhard Hickel, dds, phd

Abstract: Purpose: To provide a current status of the art, answering the question whether a certain procedure of periodontal treatment is more reliable than another and where innovative developments could improve on the incidence of hypersensitivity by a systematic literature review. Methods: Pubmed, Embase and Cochrane library were considered for the study. 2,656 articles of the PubMed search were found, from the beginning of 1945 until April 2011. 99 articles from PubMed were evaluated for this review. From Embase, 60 articles were selected and one was included in this review. From the Cochrane library, 182 were found, of which two contributed to the review. Included were all studies dealing with perio-dontal treatment followed by hypersensitivity and all studies dealing with the loss of attachment, followed by hypersensitivity. Excluded were any treatments of tooth hypersensitivity with pathogenesis not related to dentin exposure, genetically caused disorders, and fractures. Ultimately, 102 papers were evaluated, included and referred to in the review. Results: The term "tooth hypersensitivity" is most often used. Common causes of loss of hard substance are listed and updated. Mechanical loss of hard tissue formed one group of etiological factors; gingival recession and loss of attachment another. Surgical interventions, scaling and root planing were considered and in most cases performed as combined pro-cedures. The different methods were evaluated and critically discussed. There were no properly randomized studies in the literature. The weak point of all epidemiological studies is the lack of any objective measurement. With respect to perio-dontal therapy, further research and developmental work on medical devices is needed, as well as ongoing applied research with laser technologies, continuing education and training programs for professionals. (Am J Dent 2013;26:21-27).

Mail: Dr. Miriam E. Draenert, Goethestrasse 70, 80336 Munich, Germany.  E-mail: mdraener@dent.med.uni-muenchen.de

Four-year clinical  evaluation of  two  self-etching dentin adhesives of different pH values used to restore non-retentive cervical lesions

Karl-Johan M. SÖderholm, dds, mphil, phd,  Marc Ottenga, dds  &  Susan Nimmo, dds, mph

Abstract: Purpose: To evaluate the clinical performance of two self-etching adhesives of different pH values when used to restore non-retentive cervical lesions. Methods: 84 paired non-retentive class 5 restorations were originally placed in 21 subjects in need of 2, 4 or 6 restorations in incisors, canines and premolars. The retention of the placed restorations relied on the two adhesives only, which were iBOND NG plus B (iB), now marketed as iBOND Self Etch, and Clearfil SE (CB). Lesions were restored with a micro-hybrid composite (Venus). Following a baseline evaluation, the subjects were recalled and evaluated after 3 months, 1 year, 2 years and 4 years. Results: At the 4-year evaluation, 17 subjects remained who had originally received 66 restorations (33 of each adhesive). Eight of these 66 restorations had dropped out during the 4 years (4 iB and 4 CB) for different reasons. Two of the drop-outs (one iB and one CB) had fractured in the same patient, leaving a large piece of the composite still bonded to the dentin. Two other drop outs (both material iB) were not available for evaluation because they had been crowned (one after endodontic treatment and one after cusp fracture), while the remaining drop-out iB restoration had debonded. Regarding material CB, except for the fractured and partly retained drop-out restoration, the remaining three drop-outs had debonded. Pair-wise comparison of the evaluated parameters using Fishers Exact Test revealed no statistically significant (P< 0.05) differences between the two materials. (Am J Dent 2013;26:28-32).

Mail: Dr. Karl-Johan Söderholm, Department of Restorative Dental Sciences, College of Dentistry, University of Florida, 1395 Center Drive, PO Box 100415, Gainesville, FL 32610-0415, USA. E-mail: ksoderholm@dental.ufl.edu

Randomized controlled trial of the 2-year clinical performance of a silorane-based resin composite in class 1 posterior restorations

BegÜm GÜray Efes, dds, phd, Batu Can Yaman, dds, phd, Özge Gurbuz   &  Burak GumuŞtaŞ

Abstract: Purpose: To compare the 2-year clinical performance of a silorane-based resin composite with that of an established nanoceramic resin composite for class 1 posterior restorations. Methods: In this randomized controlled study, 100 class 1 molar cavities were prepared in 50 subjects. Each subject received a restoration with Filtek Silorane and Ceram.X Duo in different quadrants. The restorations were evaluated using the modified USPHS criteria at baseline and 6, 12, and 24 months. Parametric changes over the 2-year period were assessed with the Friedman test. The baseline and recall scores were compared by using the Wilcoxon signed-rank test (P< 0.05). Results: No subject developed secondary caries or postoperative sensitivity. Further, the resin composites showed no significant differences in all the evaluated parameters over 2 years (P> 0.05). At 2 years, four Filtek Silorane and seven Ceram.X Duo restorations had Bravo scores for anatomic form, marginal adaptation, and surface texture (P< 0.05); however, these changes were mainly the effect of scoring shifts from Alfa to Bravo. Overall, both materials showed good clinical results with predominantly Alfa scores. (Am J Dent 2013;26:33-38).

Mail:  Dr. Begüm Güray Efes, Department of Operative Dentistry, Faculty of Dentistry, Istanbul University, 34390 Capa, Istanbul, Turkey. E-mail:  begumguray@yahoo.com

Shear resistance of fiber-reinforced composite and metal dentin pins

Willem M.M. Fennis, dds, phd,  Joop G.C. Wolke, phd,  Camilo Machado, dds,  Nico H.J. Creugers, dds, phd & Cees M. Kreulen, dds, phd

Abstract: Purpose: To assess whether dentin pins increase shear resistance of extensive composite restorations and to compare performance of mini fiber-reinforced composite (FRC) anchors with metal dentin pins in the laboratory. Methods: 30 extracted sound molars were randomly divided into three groups. Occlusal surfaces were ground flat with a standard surface area and resin composite restorations were made in Group A. In Groups B and C similar restorations were made, with additionally four metal pins placed in Group B and four FRC pins in Group C. Specimens were statically loaded until failure occurred. Failure modes were characterized as intact remaining tooth substrate (adhesive or cohesive failure of restoration) or fractured remaining tooth substrate. Results: Mean failure stresses were 6.5 MPa (SD 3.2 MPa) for Group A, 9.7 MPa (SD 2.6 MPa) for Group B and 9.2 MPa (SD 2.6 MPa) for Group C. Difference in mean failure stresses between Group A and Groups B and C was statistically significant (P= 0.01), while the difference between Groups B and C was not (P= 0.63). Failures of the restoration without fracture of tooth substrate were seen for 80% of specimens in Group A and 20% in Groups B and C (P= 0.04). (Am J Dent 2013;26:39-43).

Mail: Dr. Willem Fennis, Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, University Medical Centre Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. E-mail: w.m.m.fennis-2@umcutrecht.nl

Microtensile bond strengths for six 2-step and two 1-step self-etch adhesive systems to enamel and dentin

Alessandra Reis, dds, phd, Alessandro Dourado Loguercio, dds, ms, phd, Adriana Pigozzo Manso, dds, ms, phd, Rosa Helena Miranda Grande, dds, ms, phd, Michelle Schiltz-Taing, Byoung Suh, phd, Liang Chen, phd &  Ricardo Marins Carvalho, dds, phd

Abstract: Purpose: To examine the microtensile bond strengths (µTBS) of six 1-step and one 2-step self-etch systems to dentin and ground enamel. Methods: Resin composite buildups were bonded to buccal and lingual ground enamel surfaces, and to occlusal dentin of third molars using the following 1-step adhesives: Xeno IV (XE), GBond (GB), Clearfil S³ Bond (CS3); Adper Prompt L-Pop (AD); Go (GO) and All Bond SE (1-step; ABSE), in comparison to the 2-steps (All Bond SE; (2-step ABSE) and Clearfil SE Bond (CSE). After storage in water (24 hour/37°C), the bonded specimens were sectioned into beams approximately 0.9 mm². These beams were tested until failure at a crosshead speed of 0.5 mm/minute. Data were subjected to appropriate statistical analysis (α= 0.05). Results: The total number of specimens/premature debonding specimens (PDS) for each adhesive were, respectively, in enamel: XE (59/36), GB (63/33), CS3 (62/29), AD (47/19), GO (53/14), 1-step ABSE (61/29), 2-step ABSE (57/14) and CSE (58/13); and in dentin: XE (51/24), GB (50/7), CS3 (53/13), ADP (51/1), GO (43/8), 1-step ABSE (59/2), 1-step ABSE (56/0) and CSE (47/0). The fracture pattern was predominantly adhesive/mixture for all adhesives in dentin (51.5 to 99%) and in enamel (34.8 to 75.4%), however XE (61.2) and GB (52.5) had more than 50% PDS. For ground enamel, no significant difference was detected among materials in the same subgroup (with or without PDS). However, there was a significant difference for all adhesives when subgroups (with and without PDS, respectively) were tested against each other: XE (7.9/10.5 ≠ 19.7/5.5), GB (8.6/10.5 ≠ 17.2/7.4), CS3 (8.8/10.3 ≠ 15.7/5.6), AD (13.0/12.0= 20.3/8.9), Go (18.2/13.8= 25.1/10.0), 1-step ABSE (15.9/11.4= 16.2/5.4), 2-step ABSE (8.4/9.1 ≠ 25.3/7.9) and CSE (17.6/16.3= 19.9/7.8). For dentin, no difference was found when subgroups for the same adhesive were tested against each other (with or without PDS). However, significantly higher resin-dentin bond strength was observed for adhesives in the following order: CSE (38.5/6.5= 38.5/6.5)≥ 2-step ABSE (41.4/16.3 ≠ 42.4/19.3)= 1-step ABSE (43.9/17.7= 44.2/17.1)= AD (34.4/14.2= 35.2/13.3)≤ CS3 (31.9/19.4= 40.1/13.4) ≠ GB (14.3/6.3= 16.3/5.9)=  Go (14.2/13.9=22.4/12.6) ≠ XE (7.1/5.4= 9.5/5.1), respectively for with PDS and without PDS. All materials showed similar performance on ground enamel. The performance of one-step self-etch systems to dentin appears to be material-dependent. Adper Prompt L-Pop, Clearfil S³ Bond and the 1-step All Bond SE had µTBS similar to Clearfil SE Bond and the 2-step All Bond SE, while Xeno IV and GBond had significantly lower µTBS values. Go had an intermediate performance. (Am J Dent 2013;26:44-50).

Mail:Prof. Alessandro Dourado Loguercio, Department of Restorative Dentistry, Faculty of Dentistry, State University of Ponta Grossa, Rua Carlos Cavalcanti, 4748 Bloco M, sala 64, CEP 84030-900 Ponta Grossa, PR, Brazil. E-mail: aloguercio@hotmail.com

Effect of polishing and finishing procedures on the surface integrity

of restorative ceramics

Tetsurou  Odatsu, dds, phd,  Ryo  Jimbo, dds, phd,  Ann  Wennerberg, lds, phd,  Ikuya  Watanabe, dds, phd &  Takashi Sawase, dds, phd

Abstract: Purpose: To investigate the effect of surface polishing and finishing methods on the surface roughness of restorative ceramics. Methods: Disk specimens were prepared from feldspar-based, lithium disilicate-based, fluorapatite leucite-based and zirconia ceramics. Four kinds of surface polishing/finishing methods evaluated were: Group 1: Control: carborundum points (CP); Group 2: silicon points (SP); Group 3: diamond paste (DP); Group 4: glazing (GZ). Surface roughness was measured using an interferometer and the parameters of Sa (average height deviation of the surface) and St (maximum peak-to-valley height of the surface) were evaluated. Data were statistically analyzed using two-way ANOVA (P< 0.05) followed by post-hoc test. The mean values were also compared by Student’s t-test. Specimen surfaces were evaluated by 3-D images using an interferometer. Results: The zirconia showed the least surface roughness (Sa and St) values after grinding with carborundum points. The significantly lowest Sa values and St values were obtained for lithium disilicate and zirconia ceramics surfaces finished with DP and GZ. The fluorapatite leucite ceramic showed significantly reduced Sa and St values from DP to GZ. The feldspathic porcelain showed the highest surface roughness values among all types of ceramics after all of the polishing/finishing procedures. (Am J Dent 2013;26:51-55).

Mail: Dr. Tetsurou Odatsu, Department of Applied Prosthodontics, Graduate School of Biomedical Science, Nagasaki University 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.  E-mail: odatsu@nagasaki-u.ac.jp

Fluoride dentifrice containing xylitol: In vitro root caries formation

Franklin  GarcÍa-Godoy, dds, ms, phd, phd,  Lisa Marie  Kao, bs, rdh,  Catherine  M. Flaitz, dds, ms

&  John  Hicks, dds, ms, phd, md

Abstract: Purpose: To evaluate the effects of experimental xylitol dentifrices with and without fluoride on in vitro root caries formation. Methods: Root surfaces from caries-free human permanent teeth (n=10) underwent debridement and a fluoride-free prophylaxis. The tooth roots were sectioned into quarters, and acid-resistant varnish was placed with two sound root surface windows exposed on each tooth quarter. Each quarter from a single tooth was assigned to a treatment group: (1) No treatment control; (2) Aquafresh Advanced (0.15% F = 1,150 ppm F); (3) Experimental xylitol dentifrice without fluoride (0.45% xylitol); and (4) Diamynt fluoride dentifrice with xylitol (0.83% sodium monofluorophosphate = 1,100 ppm F and 0.20% xylitol). Tooth root quarters were treated with fresh dentifrice twice daily (3 minutes) followed by fresh synthetic saliva rinsing over a 7-day period. Controls were exposed twice daily to fresh synthetic saliva rinsing daily over a 7-day period. In vitro root caries were created using an acidified gel (pH 4.25, 21 days). Longitudinal sections (three sections/tooth quarter, 60/group) were evaluated for mean lesion depths (water inhibition, polarized light, ANOVA, DMR). Results: Mean lesion depths were 359 ± 37 µm for the control Group; 280 ± 28 µm for Aquafresh Advanced; 342 ± 41 µm for the experimental xylitol dentifrice without fluoride; and 261 ± 34 µm for Diamynt. Aquafresh Advanced and Diamynt had mean lesion depths significantly less than those for the no treatment control and the experimental xylitol without fluoride dentifrice (P< 0.05). There were minimal non-significant differences in mean lesion depths between Aquafresh Advanced and Diamynt (P> 0.05). (Am J Dent 2013;26:56-60).

Mail: Dr. Franklin García-Godoy, Bioscience Research Center, College of Dentistry, University of Tennessee Health Science Center, 875 Union Avenue, Memphis, TN 38163, USA. E-mail: fgarciagodoy@gmail.com