Influence of Er,Cr:YSGG laser on dentin acid resistance after erosive challenge

 

Ranielle Fernandes Resende, msc, Brenda Ferreira Arantes, msc, Regina Guenka Palma Dibb, phd, Juliana Jendiroba Faraoni, phd, Denise Tornavoi de Castro, phd, Maria Angelica Hueb de Menezes Oliveira, phd, Carlos José Soares, phd, Vinícius Rangel Geraldo-Martins, phd  &  Cesar Penazzo Lepri, phd

 

Abstract: Purpose: To evaluate the influence of the Er,Cr:YSGG laser with or without the 5% fluoride varnish on the acid resistance of dentin after erosive challenge. Methods: 36 incisors were selected and sectioned, obtaining 72 specimens of 4 mm × 4 mm and randomly divided into eight groups (n = 9). In G1: application of Er,Cr:YSGG (0.1W; 5Hz, air 55%); G2: laser (0.25W; 5Hz, air 55%); G3: fluoride varnish + laser (0.1W; 5Hz, air 55%); G4: fluoride varnish + laser (0.25W, 5Hz, air 55%); G5: fluoride varnish + laser (0.1W; 5Hz, without air); G6: fluoride varnish + laser (0.25W, 5Hz, without air); G7: fluoride varnish and G8: no treatment. When used, the laser was irradiated without water cooling, scanning mode during 10 seconds. The surface roughness data were subjected to ANOVA. For wear profile, we used Kruskal-Wallis test and Dunn post-hoc, all with α= 0.05. Results: The results showed no statistically significant difference when comparing the groups as regards to the surface roughness (P> 0.05). Regarding the percentage of lost volume, the G5 and G6 groups presented the best results (G5 = 7.8% and G6 = 8.5%), with the lowest loss of dentin volume compared to other groups (P< 0.05). The G8 group (no treatment) had the highest lost volume (G8 = 39.1% followed by the G7 group (fluoride varnish), which had 25.9%. (Am J Dent 2019;32:215-218).

 

 

Mail: Dr. Cesar Penazzo Lepri, Biomaterials Division, Faculty of Dentistry, University of Uberaba, Av. Nenê Sabino, 1801, 2D06 - Universitário – CEP: 38055-500. Uberaba, MG, Brazil. E-mail: cesarlepri@yahoo.com.br

 

 

Bacterial microleakage of a bioactive pit & fissure sealant. An in vitro evaluation

 

Osvaldo Zmener, dds, dr odont  &  Cornelis H. Pameijer, dmd, mscd, dsc, phd

 

Abstract: Purpose: To compare the sealing properties of three pit and fissure (P&F) sealants, Embrace Wet Bond (EWB), a bioactive P&F sealant Embrace Wet Bond through the addition of modified calcium phosphate (MCP) (EWBMCP) and ClinPro (CLPR). The sealing properties of the materials were tested by means of a bacterial microleakage test. Methods: 30 extracted intact human third molars were randomly assigned to three groups of 10 (n=10) teeth each. The teeth were cleaned with two passes of air abrasion, followed by rinsing for 20 seconds and then dried with compressed air for another 20 seconds leaving the enamel surface slightly moist. The coronal portion of each tooth was sectioned perpendicular to the long axis at the level of 4 mm below the top of the central fossa of the enamel. A parallel vertical channel 1 mm in diameter was prepared in the central fossa through the entire sample. All samples were sterilized with Gamma radiation. After etching the occlusal surface with 35% phosphoric acid gel followed by rinsing, the sealants were applied. The samples were stored at 37°C in SPB for 3 weeks, thermal cycled for 2,000× (5-55°C) and coated with nail varnish leaving 1 mm uncovered around the P&F material. Samples were then tested for microleakage of E. faecalis culture using a dual chamber leakage model. The broth in the lower chamber was checked daily for turbidity up to 90 days. Statistical significance was determined at P< 0.05. Results: The median survival time for EWBMCP was significantly higher (P< 0.05) than for EWB and CLPR. With respect to bacterial microleakage frequency, EWBMCP and CLPR behaved significantly better than EWB. The bioactive sealant EWBMCP outper-formed the other two tested sealants in terms of resistance to bacterial microleakage. Long-term clinical studies are recommended to confirm these in vitro findings. (Am J Dent 2019;32:219-222).

 

 

 

 

 

Mail: Dr. Cornelis H. Pameijer, 2002 SW Laredo St., Palm City, FL  34990, USA.  E-mail: cornelis@pameijer.com

 

 

 

Three-year clinical evaluation of universal adhesives in non-carious cervical lesions

 

Vanessa C. Ruschel, dds, ms, phd, Sheila C. Stolf, dds, ms, phd, Shizuma Shibata, dds, ms, phd, Yunro Chung, ms, phd, Lee W. Boushell, dmd, ms, Luiz N. Baratieri, dds, ms, phd  &  Ricardo Walter, dds, ms

 

Abstract: Purpose: To compare the performance of universal adhesives containing different monomers, namely 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) and dipentaerythritol penta-acrylate monophosphate (PENTA), in the restoration of non-carious cervical lesions (NCCLs). Methods: This was a randomized controlled clinical trial involving 63 subjects in need of restorations of 203 NCCLs. Notch-shaped lesions were restored with Kalore (GC Corporation) after application of Scotchbond Universal (SU) or Prime&Bond Elect (PBE) following the etch-and-rinse (ER) or self-etch (SE) technique. Restorations were assessed after 1 week, 18 and 36 months. Logistic regression was performed for each outcome separately with compound symmetric variance-covariance structure assumed to consider a correlation of restorations within subjects. All analyses were conducted using SAS 9.4 (SAS). Results: 150 teeth in 41 subjects were assessed at 36 months. Three restorations in the PBE_SE group failed the retention criterium. Statistically significant differences were reached for the following comparisons: restorations with SU_SE were 75% less likely to maintain a score of Alfa for marginal discoloration than PBE_SE; restorations with PBE_SE were 83% less likely to maintain a score of Alfa for marginal adaptation than PBE_ER. (Am J Dent 2019;32:223-228).

 

 

Mail: Dr. Ricardo Walter, Department of Restorative Sciences, University of North Carolina, 425 Brauer Hall, CB #7450, Chapel Hill, NC, 27599-7450, USA. E-mail: walterr@unc.edu

 

 

Influence of ceramic laminate on water sorption, solubility, color stability, and microhardness of resin cements

 

Anna Rebeca de Barros Lins Silva Palmeira, dds, Waldemir Francisco Vieira Junior, dds, ms, phd, Flávia Lucisano Botelho do Amaral, dds, ms, phd, Roberta Tarkany Basting, dds, ms, phd, Cecília Pedroso Turssi, dds, ms, phd  &  Fabiana Mantovani Gomes França, dds, ms, phd

 

Abstract: Purpose: To evaluate the influence of ceramic laminate on color stability, surface microhardness, water sorption, and solubility of resin luting agents. Methods: Disk-shaped specimens (10 × 2 mm) of dual-cured resin cements (RelyX ARC or RelyX Ultimate) were obtained, and a light-cured luting agent (RelyX Veneer) was used. In Experiment 1, disk-shaped resin cements (n = 10) were submitted to: I) polymerization with or without ceramic laminate (0.7 mm), and II) immersion in distilled water or coffee, 3 hours daily for 20 days. The surface microhardness loss (%SML) was determined, and the color variables were assessed by the CIE L*a*b* system (ΔE, ΔL*) and the shade guide units (ΔSGU). In Experiment 2, other disk-shaped specimens (n = 5) were submitted to polymerization with or without ceramic laminate to assess their water sorption (WS) and solubility (S). Statistical analysis was performed using 3-way ANOVA and Tukey’s test for ΔE, ΔL* and %SML; Mann-Whitney, Kruskal-Wallis, and Dunn’s tests for ΔSGU; and 2-way ANOVA and Tukey’s test for WS and S. The significance level was set at 5%. Results: No statistically significant differences among the resin cements was observed for %SML, WS, or S, regardless of stain exposure or presence of ceramic laminate during light activation. Coffee caused a significant decrease in ΔL* values. All the resin cements presented visually detectable color alteration for ΔE; however, RelyX Ultimate showed less color change after coffee exposure. RelyX ARC showed the greatest color change in water. RelyX Veneer presented the highest values of ΔSGU, compared with the other resin cements. The WS, S, and %SML of resin cements were not influenced by the staining solution or the presence of ceramic laminate during light activation; however, RelyX Ultimate resin cement presented the best color stability. (Am J Dent 2019;32:229-234).

 

 

 

Mail: Profa. Dra. Fabiana Mantovani Gomes França, Faculty São Leopoldo Mandic, Research Institute São Leopoldo Mandic, Rua José Rocha Junqueira, 13 Swift, Campinas, SP CEP: 13045-755, Brazil. E-mail: biagomes@yahoo.com

 

 

Effect of whitening mouthrinses on bulk-fill composites

 

Sandrine Bittencourt Berger, dds, msc, phd, Zanelli Petri, dds, Viviane Hass, dds, msc, phd, Ricardo Danil Guiraldo, dds, msc, phd, Jaqueline Costa Favaro, dds, msc, Murilo Baena Lopes, dds, msc, phd   &  Alejandra Hortencia Miranda González, dchem, msc, phd

 

Abstract: Purpose: To evaluate the effect of whitening mouthrinses on sorption (SP) and solubility (SL), percentage of microhardness change (%M), loss of surface (LS), and color change (ΔE) in bulk-fill composites when compared with conventional composites. Methods: Three bulk-fill composites, Surefil SDR (SF), Filtek Bulk-Fill (BF), and Filtek Bulk-Fill Flow (BFF), and one conventional resin, Filtek Z350 (FZ), were selected. Eighteen samples of each composite were subdivided into three groups based on the type of treatment: Listerine Whitening mouthrinse (LW), Colgate Plax Whitening mouthrinse (CP), and distilled water (DW; control). The samples were prepared according to ISO 4049:2009. Color, roughness, and microhardness were evaluated before and after treatment, while SP and SL values were measured after treatment. The surface morphology of the specimen was examined using scanning electron microscopy. Data were analyzed using two-way ANOVA and Tukey's test. Results: FZ presented significantly lower ΔE when immersed in DW. Additionally, LS was lowest in FZ when compared with the other resins. SF and BFF demonstrated high %M. SL was significantly higher in SF, whereas SP was lowest in BFF after CP treatment. No significant alterations in surface morphology were noted in the BF composites. The BF composites showed a decrease in their properties after immersion in the two types of mouthrinses or in DW, without alterations in the surface morphology. (Am J Dent 2019;32:235-239).

 

 

Mail: Dr. Sandrine Berger, UNOPAR - University of North Parana, Rua Marselha, 183 - Jardim Piza, 86041-120 Londrina, PR, Brazil.  E-mail: berger.sandrine@gmail.com

 

 

 

Effect of monolithic CAD-CAM ceramic thickness on resin cement polymerization: An in-vitro study

 

Mustafa Borga Dönmez, dds, phd  &  Munir Tolga Yücel, dds, phd

 

Abstract: Purpose: To evaluate the effect of different thicknesses of CAD-CAM ceramic sections on the polymerization of two different resin cements. Methods: Three CAD-CAM all-ceramic restorative materials were sectioned with four different thicknesses. A total of 240 resin cement specimens were prepared from light cured and dual cure resin cements and absorption peaks were recorded. 10 samples of each resin cement were examined before and after polymerization and served as the control group. Data were analyzed using one-way ANOVA, independent t- and Tukey HSD tests (P< 0.05). Results: Control group showed the highest DOC values while samples cured under Vita Enamic section with a thickness of 2 mm presented the lowest values (P< 0.05). Polymerization performed under sections of 0.5 and 1 mm thicknesses provided statistically higher values. Dual cured resin cement samples showed higher DOC values compared to light cured resin cement samples. IPS Empress CAD sections with 0.5 and 1 mm thickness exhibited statistically higher values than other ceramics of the same thickness for light cured resin cement samples. A significant difference was observed between IPS Empress CAD and Vita Enamic while comparing ceramic sections of the same thickness (P< 0.05). There was no difference for sections of 1.5 and 2 mm (P> 0.05). (Am J Dent 2019;32:240-244).

 

 

 

Mail: Dr. Mustafa Borga Dönmez, Dentapol Dental Clinic, Ankara, Turkey. E-mail: borgadonmez@gmail.com

 

 

Effect of toothpaste containing multiple ions-releasing filler on polymicrobial biofilm regrowth and dentin demineralization

 

Kiyoshi Tomiyama, dds, phd, Toru Shiiya, dds, phd, Kiyoko Watanabe, phd, Nobushiro Hamada, dds, phd &  Yoshiharu Mukai, dds, phd

 

Abstract: Purpose: To compare the efficacy of toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler particles to that of conventional sodium fluoride (NaF) toothpaste for the prevention of dentin demineralization and biofilm regrowth. Methods: Bovine root dentin specimens and glass coverslips were used as biofilm growth substrates. To establish biofilms, glass and dentin specimens were incubated for 72 hours in 0.2% sucrose McBain medium inoculated with stimulated saliva from a single donor. Specimens then received a single 5-minute treatment with S-PRG toothpaste, fluoride toothpaste, or sterilized deionized water and were incubated in McBain medium for 120 hours to allow biofilm regrowth. Output parameters during regrowth (72-192 hours) were pH of spent medium, colony-forming unit (CFU) counts of biofilms, and dentin mineral profiles, integrated mineral loss (IML: vol% × µm), and lesion depth (Ld). Treatment group differences were tested by one-way ANOVA followed by Tukey’s multiple range test (P< 0.05). Results: At 144 hours, medium pH was significantly higher in the S-PRG-treated dentin group than in the NaF-treated dentin group. In addition, at 192 hours, the CFU count, IML, and Ld were lower in the S-PRG-treated dentin group than in the NaF-treated dentin group. There were significant differences of pH among dentin groups at 72 hours. Treatment with S-PRG toothpaste markedly inhibited dentin demineralization compared to that with NaF toothpaste. (Am J Dent 2019;32:245-250).

 

 

Mail: Dr. Kiyoshi Tomiyama, Division of Cariology and Restorative Dentistry, Department of Oral Function and Restoration, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka, Kanagawa 238-8580, Japan. E-mail: tomiyama@kdu.ac.jp

 

 

Evaluation of the accuracy of the mechanical torque wrench by the number of uses and ratchet type

 

Tahir Karaman, dds, phd, Onur Evren Kahraman, dds, phd, Bekir Eser, dds, phd, Eyyup Altintas, dds, phd, Tuba Talo Yildirim, dds, phd  &  Faruk Oztekin, dds, phd

 

Abstract: Purpose: To evaluate the accuracy of mechanical torque rachet types based on the number of uses. Methods: A total of 25 ratchets, including three frictional- and two spring-type torque ratchets from every mechanical torque ratchet group, were used in our study. A digital torque measurement device was used in assessing the efficiency of mechanical torque ratchets. All ratchets were tightened according to the torque values recommended by the companies. The ratchets were tightened 500 times in total. Results: Given the changes in torque delivery by the number of uses, a statistically significant torque loss was observed in the Bego ratchets (P< 0.05), and a statistically significant increase was found in the torque values of the other ratchet groups (P< 0.05). The highest increase in torque values was obtained in the MEDENTİKA ratchet group. (Am J Dent 2019;32:251-254).

 

 

Mail: Dr. Tahir Karaman, Department of Prosthodontics, Faculty of Dentistry, Firat University, Elazig, Turkey. E-mail: tkaraman@firat.edu.tr

 

 

 

The influence of zirconia coping designs on maximum principal stress distribution in all-ceramic premolar crowns: A finite element analysis

 

Burcu Diker, dds  &  Selim Erkut, dds, phd

 

Abstract: Purpose: To evaluate the effects of different coping designs on maximum principal stresses in the veneering material using a finite element analysis method. Methods: A maxillary first premolar tooth model was prepared. The primary and prepared tooth model were scanned with a 3D (three dimensional) scanner. Four different coping and veneer models were designed with 3D computer-aided design software: conventional design (DC); design with 3 mm palatal shoulder (DP); design with 1 mm buccal shoulder and 3 mm palatal shoulder (DB); and design with buccal facet (DF). After the models were designed, they were transferred to the finite element analysis (FEA) software for analyses. The middle points of the buccal, mesial, distal and palatal surfaces were determined in the cervical region. For all models, the maximum principal stress distributions and values of porcelain veneer were evaluated under centric occlusion loading and laterotrusive loading conditions with a FEA. Results: The maximum principal stress area decreased gradually from model DC to model DB on the buccal cervical region under centric occlusion loading. However, models DF and DP showed similar stress distribution. The maximum principal stress at the distal point decreased from DC (14.7 MPa) to DP (13.5 MPa) and DB (9.6 MPa), whereas increased in model DF (33 MPa). Under laterotrusive loading, both the palatal maximum principal stress area and the stress value at the palatal point (model DC: 13.1 MPa, model DP: 3 MPa, model DB: 4MPa) decreased with the palatal shoulder. (Am J Dent 2019;32:255-259).

 

 

 

 

Mail: Dr. Burcu Diker, Department of Prosthodontics, Faculty of Dentistry, Istanbul Okan University, University Tuzla Campus, 34959, Akfırat-Tuzla/Istanbul, Turkey. E-mail: burcu.diker@okan.edu.tr, dtburcuf@gmail.com

 

 

 

Interfacial sealing between normal dentin and caries-affected dentin

with glass-ceramic and three types of bonding systems

 

Zhengxi Wu, mstomatol, Fenglan Li, phd, dds, Cheng Liu, mstomatol  &  XiaoJing Si, mstomatol

 

Abstract: Purpose: To compare the bonding effect of normal dentin (ND) and caries-affected dentin (CAD) on the surface of glass-ceramics using three types of bonding systems. Methods: 39 teeth with caries involving the superficial layer of dentin were randomly divided into three groups and two subgroups: nanoleakage group (n=5) and shear bond strength group (n=8). The infected dentin was removed, and the CAD was retained. The surface of the tooth was polished, and one 2 mm × 2 mm × 4 mm CAD block and one 2 mm × 2 mm × 4 mm ND block were made. The total-etch adhesive A, self-etch adhesive B, or self-adhesive resin adhesive C were used to bond the glass ceramics. The bonding specimens of the nanoleakage group were stained with ammoniated silver nitrate and observed. In the shear bond strength group, the maximum load of the loading head F (N) was recorded, and the shear bond strength of the specimen was calculated. Results: The nanoleakage values were significantly lower than those in the CAD group. The nanoleakage value of group B was significantly higher than that of group C, and that of group C was significantly higher than that of group A. Both dentin type and adhesive type had an effect on shear bond strength; under the same adhesive system, normal dentin demonstrated higher shear bond strength than CAD. However, the shear bond strength of adhesive A was higher than the bond strengths of adhesives B and C, but there was no significant difference in shear bond strength between adhesives B and C. (Am J Dent 2019;32:260-264).

 

 

 

 

 

 

Mail: Dr. Fenglan Li, Shanxi Provincial People's Hospital Affiliated to Shanxi Medical University, Taiyuan 030012，China. E-mail: uniquelfl@163.com