Effect of thermal and acid challenges on the surface properties of pink restorative materials

 

Erika Michele dos Santos Araújo, dds, Beatriz Togoro Ferreira da Silva, dds, Luciana Kfouri Siriani, dds, phd, Andréa Dias Neves Lago, phd, Maria Regina Lorenzetti Simionato, dds, phd  &  Adriana Bona Matos, phd

 

Abstract: Purpose: To compare the effect of thermal cycling and erosive challenge on color change, surface roughness, surface loss and biofilm deposition of three resin-based composites. Methods: Three resin-based composites that reproduce the color of gingival tissues [two nanohybrid composites (A and B) and a giomer (C)] were tested before and after distinct challenges [thermal cycling (TC) and erosive challenge (EC)] in regard to its color stability, surface roughness, surface loss and biofilm deposition. Surface roughness and surface loss specimens (n=10) were measured with an optical profilometer and, color stability (n=10) was measured with a spectrophotometer. Biofilm deposition (n=5) was measured after 3 and 24 hours by safranin staining. Results: Two-way ANOVA test was performed to analyze color change, roughness and surface loss. A significant color change was detected for resin-based composites (P< 0.05) and its interaction with tested challenges (P< 0.05). The highest color variation was observed on the giomer after erosive challenge. Surface loss was not different between tested groups (P= 0.708). The roughness was significantly higher in specimens submitted to thermal cycling (P> 0.05). For biofilm quantification, after 3 and 24 hours, ANOVA (3-way) detected significance for the interaction of challenges and resin-based composites (P< 0.05 and P< 0.05, respectively). All resin-based composites presented color changes after challenges; higher roughness was observed after thermal cycling for all resin-based composites tested, without significant surface loss; and higher biofilm deposition was observed on the giomer samples when submitted to erosive challenge after 3 and 24 hours. (Am J Dent 2019;32:159-164).

 

 

 

Mail: Dr. Erika Michele dos Santos Araújo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitária, São Paulo - SP - CEP 05508-000, Brazil. E-mail: erikaaraujo@usp.br

 

Mechanical behavior of conceptual posterior dental crowns with functional elasticity gradient

 

Marcela Moreira Penteado, dds, msc,  João Paulo Mendes Tribst, dds, msc, Amanda Maria de Oliveira Dal Piva, dds, msc,  Pietro Ausiello, dds, ms, phd,  Fernando Zarone, dds, msc, Franklin Garcia-Godoy, dds, ms, phd, phd  &  Alexandre Luiz Souto Borges, dds, msc, phd

 

Abstract: Purpose: To evaluate the biomechanical behavior of monolithic ceramic crowns with functional elasticity gradient. Methods: Using a CAD software, a lower molar received a full-crown preparation (1.5 mm occlusal and axial reduction). The monolithic crown was modeled with a resin cement layer of 0.1 mm. Four groups were distributed according to the full crown elastic modulus (E):(a) Bioinspired crown with decreasing elastic modulus (from 90 to 30GPa); (b) Crown with increasing elastic modulus (from 30 to 90 GPa); (c) Rigid crown (90 GPa) and (d) Flexible crown (30 GPa). The model was exported to the analysis software and meshed into 385.240 tetrahedral elements and 696.310 nodes. Materials were considered isotropic, linearly elastic, and homogeneous, with ideal contacts. A 300-N load was applied at the occlusal surface and the base of the model was fixed in all directions. The results were required in maximum principal stress criterion. Results: Crowns consisting of layers with increasing elastic modulus presented intermediate results between the rigid and flexible crowns. Compared to the flexible crown, the bioinspired crown showed acceptable stress distribution across the structure with lower stress concentration in the tooth. In dental crowns the multilayer structure with functional elasticity gradient modifies the stress distribution in the restoration, with promising results for bioinspired design. (Am J Dent 2019;32:165-168).

 

 

 

Mail: Dr. Pietro Ausiello, School of Dentistry, University of Naples Federico II, via Sergio Pansini n. 5,  80131 Naples, Italy. E-mail: pietro.ausiello@unina.it

 

The effect of diamond toothpastes on surface gloss of resin composites

 

Ingrid Fernandes Mathias-Santamaria, dds, msc, phd  &  Jean-François Roulet, dds, phd

 

Abstract: Purpose: To evaluate the effect of diamond toothpastes on the gloss surface of five resin composites. Methods: 30 discs of each resin composite in A2 shade [Filtek Supreme Ultra (FS), Tetric EvoCeram (TE), IPS Empress Direct (ED), Charisma (CC), Venus Diamond (VD)] were made. The samples were divided into three groups according to the toothpaste: Colgate Total Clean Mint (control) (CTC), Candida White Diamond (CWD) and Emoform-F Diamond (EFD). After standardized polishing, the samples were brushed using a toothbrushing simulator, and gloss measurements were assessed at baseline and 15, 30, 45, 60, 75, 90, 105 and 120 minutes. Results: Diamond toothpastes behaved dif-ferently from each other: the CWD and CTC groups presented the lowest values compared to EFD (P< 0.05). Nanofilled composites presented higher gloss values than other composites when brushed with various toothpastes (P< 0.05). The addition of diamond particles as abrasives in toothpastes can affect resin composites’ surface gloss. (Am J Dent 2019;32:169-173).

 

 

Mail: Dr. Ingrid Fernandes Mathias-Santamaria, Department of Diagnosis and Surgery, Institute of Science and Technology, São Paulo State University - UNESP, São José dos Campos, SP, Brazil.  E-mail: ingridfmsantamaria@gmail.com

 

Microtensile bond strength to dentin and enamel of self-etch vs. etch-and-rinse modes of universal adhesives

 

Joana Cruz, dds, Bernardo Sousa, dds, ms, Catarina Coito, dds, ms, Manuela Lopes, phd, Marcos Vargas, dds, ms &  Alexandre Cavalheiro, dds, ms, phd

 

Abstract: Purpose: To compare the immediate microtensile bond strengths (µTBSs) of four mild self-etch universal adhesives applied to dentin and enamel with self-etch and etch-and-rinse techniques. Methods: Flat middle dentin surfaces from 104 human teeth and two enamel fragments from another 104 human teeth were randomly distributed into eight groups according to the various adhesive systems used: Scotchbond Universal (SBU) [etch-and-rinse mode vs. self-etch mode]; Optibond XTR (OPT) [etch-and-rinse mode vs. self-etch mode]; Clearfil Universal Bond Quick (CL) [etch-and-rinse mode vs. self-etch mode]; and Adhese Universal (ADH) [etch-and-rinse mode vs. self-etch mode]. After 24 hours of water storage, the bonded sticks were tested for μTBS. The differences in the pre-test failure and fracture-failure modes were tested by a two-way ANOVA and GEE model analysis. Bond-strength data were analyzed with a two-way ANOVA and mixed-model analysis. Results: For dentin, the mean µTBS was statistically different among the four adhesives, but not different between the self-etch and etch-and-rinse modes. For enamel, the mean µTBS was statistically different among the four adhesives, as was the application mode. GEE model analysis revealed a statistically significant adhesive failure rate proportion among the four types of adhesives for both enamel and dentin. (Am J Dent 2019;32:174-182).

 

 

 

 

Mail: Dr. Joana Cruz, Faculty of Dental Medicine, University of Lisbon, Rua Professora Teresa Ambrósio, Cidade Universitária, 1600-277, Lisbon, Portugal.  E-mail: joanacruz2@gmail.com

 

 

Altered levels of salivary biochemical markers in periodontitis

 

Zohreh Khodaii, md, phd, Mahboobeh Mehrabani, phd, Nasrin Rafieian, dds, Gholam Ali Najafi-Parizi, dds, Ahmadreza Mirzaei, msc  &  Reza Akbarzadeh, phd

 

Abstract: Purpose: To investigate the association between periodontitis and levels of biochemical markers as well as enzyme activity. Methods: Unstimulated whole saliva samples were obtained from 30 patients with periodontitis. Biochemical factors including the levels of malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO), uric acid (UA), and lactoferrin, as well as β-hexosaminidase (β-HEX) activity were measured. Results: The levels of a salivary oxidant such as MDA and NO were statistically significantly higher in periodontitis patients than to that of healthy individuals. Similarly, the results indicated elevated levels of lactoferrin and β-HEX activity in saliva of the periodontitis group, which was statistically significant when compared to the controls. While the levels of an enzymatic antioxidant such as SOD were higher in the periodontitis patients than in the control subjects, uric acid levels were statistically significantly lower in the saliva of the periodontitis patients than in the healthy controls. (Am J Dent 2019;32:183-186).

 

 

 

Mail: Dr. Reza Akbarzadeh, Institute of Anatomy, University of Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany. E-mail: akbarzadeh@anat.uni-luebeck.de

 

 

Effects of different treatments of the ridge surface on the shear bond strength between acrylic teeth and thermal polymer resin

 

Jiangang Mu, md, Mengdong Liu, md, Wenjing Jiang, md, Defeng Liu, md   &  Tingting Yan, md

 

Abstract: Purpose: To evaluate the shear bond strength between denture base and artificial teeth subjected to five different modifications on the ridge surface. Methods: 30 acrylic central anterior teeth were randomly divided into five groups (n= 6). The ridge surface of these teeth were treated with different methods: (1) No treatment applied; (2) Monomer wetting; (3) Grinding; (4) Grinding followed by sandblasting; (5) Grinding followed by monomer wetting. After the ridge surface of the teeth were treated, they were packed with denture base resin. The shear bond strength between acrylic teeth and denture base resin was performed using a universal testing machine. The data was statistically analyzed using one-way ANOVA (P< 0.05). Results: The monomer wetting group showed the highest shear bond strength values, and the grinding followed by sandblasting group was the lowest, both were statistically significant compared to each other. There were no statistical differences between the other groups. (Am J Dent 2019;32:187-190).

 

 

 

Mail: Dr. Jiangang Mu, Department of Dentistry, The Affiliated Hospital of Qingdao University, No.16 Jiangsu Road, Qingdao 266003, Shandong Province, PR China.  E-mail: qdbr2007@163.com

 

 

In vitro evaluation of the effectiveness of alkaline peroxide solutions in reducing the viability of specific biofilms

 

Helena de Freitas Oliveira Paranhos, dds, msc, phd,  Flávia Cristina Targa Coimbra, dds, msc, Marcela Moreira Salles, dds. msc, Viviane de Cássia Oliveira, bsc, msc, Ana Paula Macedo, bse, msc, phd, Valéria Oliveira Pagnano, dds, ms, phd  &  Cláudia Helena Lovato da Silva, dds, msc, phd

 

Abstract: Purpose: To evaluate in vitro the effectiveness of eight different cleansers containing alkaline peroxide against yeast [Candida albicans (Ca) and Candida glabrata (Cg)], Gram-negative bacteria [Escherichia coli (Ec) and Pseudomonas aeruginosa (Pa)], and Gram-positive bacteria [Bacillus subtilis (Bs), Enterococcus faecalis (Ef), Staphylococcus aureus (Sa), and Streptococcus mutans (Sm)]. Methods: Denture base acrylic resin specimens (Lucitone 550; 1264 denture base acrylic resin specimens) were obtained from a circular metal matrix (15 × 3 mm) and sterilized with microwave irradiation (650 W, 6 minutes). The specimens were contaminated with 10⁶ CFU/mL suspension of yeasts and 10⁸ CFU/mL suspensions of Gram-positive and -negative bacteria. The contaminated specimens were incubated (37°C/48 hours) and immersed (short cycle) in a stainless steel basket placed in a beaker. The beaker contained one of the following cleanser solutions, which were prepared and used according to the manufacturers’ instructions (n=10): PBS (positive control, C), Fixodent (FI), Medical Interporous (MI), Kukident (KU), Efferdent Plus (EF), Equate (EQ), Kroger (KR), Kirari (KI), and Corega Tabs (CT). Reduction in the viability of microorganisms was evaluated through counting of Colony Forming Units (CFU/mL), metabolic activity (XTT), and cell viability by epifluorescence microscopy (EM) analyses. For counting CFU, the specimens (n=10 of each group) were washed and immersed in Letheen medium, from which aliquots were obtained and seeded into selective solid culture media. After incubation (37°C, 24 hours), the colonies were counted (CFU/mL). The metabolic activity of microorganisms was measured using XTT reduction assay (n=5). For EM analysis, the specimens (n= 2 of each group) were stained (Live/Dead BacLight), and the images were analyzed in terms of biofilm areas (total and living cells). Data were processed and analyzed by Wilcoxon, Mann Whitney and Kruskal-Wallis tests followed by Dunn test (α= 0.05). Results: Significant differences were found between the experimental groups and C for the evaluated microorganisms. MI was the most effective for yeasts; this cleanser reduced the metabolic activity, viability, and total counts of both yeasts evaluated. All cleansers reduced the total counts of Gram-negative microorganisms, except CT for Pa. For Gram-negative bacteria, KR, CT, EF, and EQ significantly reduced the metabolic activity of Ec but did not remove all dead cells. FI and MI significantly reduced the metabolic activity of Pa, and the latter also removed the dead cells of Pa. FI and MI showed improved results against all Gram-positive bacteria. Both cleansers significantly decreased the metabolic activity of all bacterial species and reduced the viability of Sa, Ef, and Bs. MI also reduced the biofilm aggregates of Sm. (Am J Dent 2019;32:201-207).

 

 

Mail: Dr. Helena de Freitas Oliveira Paranhos, Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo, Avenida do Café S/N, Ribeirão Preto-SP, CEP: 14040-904, Brazil. E-mail: helenpar@forp.usp.br

 

Influence of sonic application on surface roughness of bulk-fill resin composites

 

Barbara B. da Silva Lontra, dds, ms, Apoena A. Ribeiro, dds, ms, phd, Eduardo M. Sampaio, beng, ms, phd, Ricardo Walter,dds, ms  & Adalberto B. de Vasconcellos, dds, ms, phd

 

Abstract: Purpose: To evaluate the influence of sonic application on the surface roughness of bulk-fill resin composite restorations. Methods: 80 intact bovine incisors had their incisal thirds removed, their buccal surfaces flattened, and standard preparations mimicking Class II preparations performed on their buccal surfaces. Specimens were then randomly assigned for restoration with the bulk-fill resin composites Tetric EvoCeram Bulk Fill, SureFil SDR flow+, and SonicFill 2, with sonic application for 15 seconds and 30 seconds as well as no sonic application. Filtek Supreme Ultra applied without sonic application served as control. Sonic application was accomplished with the KAVO SONICflex handpiece. Surface roughness was measured using a 3D scanner and data were analyzed using the Kruskal-Wallis and Mann-Whitney tests at a significance level of 0.05. Results: No statistical differences were found between groups treated with and without sonic application. When materials were compared, Tetric EvoCeram Bulk Fill showed the lowest surface roughness in the 15-second sonic application subgroup; and SureFil SDR flow+ showed the highest surface roughness when applied without sonic application and in the 30-second sonic application subgroups. (Am J Dent 2019;32:208-212).

 

 

 

Mail: Dr. Adalberto B. de Vasconcellos, Department of Restorative Sciences, Division of Operative Dentistry and Biomaterials, School of Dentistry, University of North Carolina, 433 Brauer Hall, CB # 7450, Chapel Hill, NC, USA. E-mail: bert_vasconcellos@unc.edu

 

The impact of non-surgical therapy of periodontal disease on surrogate markers for cardiovascular disease: A literature review

 

Orlando D’Isidoro, dds, Vittoria Perrotti, dds, phd, Wang Lai Hui, bds, mmedsc, Adriano Piattelli, md, dds, Flavia Iaculli, dds, phd & Alessandro Quaranta, dds, phd

 

Abstract: Purpose: To review the literature on the effects of non-surgical periodontal treatment on surrogate markers of cardiovascular diseases (CVDs) and to clarify the impact of periodontal disease on systemic inflammation. Methods: PRISMA guidelines for systematic reviews and meta-analyses have been adopted. An electronic search in PubMed up to December 2018 was performed using the following search terms and keywords alone or in combination: non surgical periodontal therapy, atherosclerotic vascular disease (AVD), operative surgical procedures, CVD, IL-6, CRP, cholesterol, LDL, oxidized low density lipoprotein, HDL, endothelial dysfunction, dependent dilatation, carotid intima media thickness, periodontitis, tunica intima. Results: The electronic search resulted in the inclusion of 28 articles that were grouped and discussed based on the investigated surrogate markers. Meta-analysis was not carried out due to the heterogeneity of the results. The included studies demonstrated that periodontal treatments contribute to the resolution of oral inflammation and in turn might positively modulate the levels of systemic inflammatory markers. The initial phase of periodontal therapy has a positive impact on the short-term reduction of a series of systemic markers that are considered as surrogate markers of AVD. (Am J Dent 2019;32:191-200).

 

 

Mail: Dr. Vittoria Perrotti, Via dei Vestini 31- 66100 Chieti, Italy. E-mail: v.perrotti@unich.it