Scielo RSS <![CDATA[Journal of Applied Oral Science]]> vol. 27 num. lang. en <![CDATA[SciELO Logo]]> <![CDATA[Surface morphology and mechanical properties of conventional and self-adhesive resin cements after aqueous aging]]> Abstract The stable long-term performance of resin cement under oral environmental conditions is a crucial factor to obtain a satisfactory success of the allceramic dental restoration. Objective: This study aimed at evaluating and comparing the surface morphology and mechanical property of conventional and self-adhesive resin cement after aqueous aging. Materials and Methods: Disc-shaped specimens of 3 conventional (C1: Multilink N, C2: Duolink, C3: Nexus 3) and 3 self-adhesive (S1: Multilink Speed, S2: Biscem, S3: Maxcem) types of resin cements were subjected to irradiation. After 24 h, the Knoop microhardness of each resin cement was evaluated. The specimens were immersed separately in distilled water and maintained at 37°C. A total of 5 specimens of each resin cement were collected at the following time intervals of immersion: 1, 6, 12 and 18 months. The samples were used to evaluate the Knoop parameters of microhardness, sorption and solubility. The surface morphology of the specimens after 18 months of immersion was observed by scanning electron microscopy. The sorption and solubility data were analyzed by two-way ANOVA. The Knoop microhardness was tested by the ANOVA repeated measures (P&lt;0.05). Results: The sorption and solubility parameters of C1 and S1 exhibited significant fluctuations during the aqueous aging. The hardness of the S1 and S2 specimens decreased significantly after an 18-month water immersion. The S1, S2 and S3 specimens indicated higher filler exposure and stripping and apparent pores and cracks compared to specimens C1, C2 and C3, respectively. Conclusion: The surface of selfadhesive resin cements is more susceptible to aqueous damage than that of the conventional resin cements. <![CDATA[Stanozolol promotes osteogenic gene expression and apposition of bone mineral <em>in vitro</em>]]> Abstract Stanozolol (ST) is a synthetic androgen with high anabolic potential. Although it is known that androgens play a positive role in bone metabolism, ST action on bone cells has not been sufficiently tested to support its clinical use for bone augmentation procedures. Objective: This study aimed to assess the effects of ST on osteogenic activity and gene expression in SaOS-2 cells. Material and Methods: SaOS-2 deposition of mineralizing matrix in response to increasing doses of ST (0-1000 nM) was evaluated through Alizarin Red S and Calcein Green staining techniques at 6, 12 and 24 days. Gene expression of runt-related transcription factor 2 (RUNX2), vitamin D receptor (VDR), osteopontin (SPP1) and osteonectin (ON) was analyzed by RT-PCR. Results: ST significantly influenced SaOS-2 osteogenic activity: stainings showed the presence of rounded calcified nodules, which increased both in number and in size over time and depending on ST dose. RT-PCR highlighted ST modulation of genes related to osteogenic differentiation. Conclusions: This study provided encouraging results, showing ST promoted the osteogenic commitment of SaOS-2 cells. Further studies are required to validate these data in primary osteoblasts and to investigate ST molecular pathway of action. <![CDATA[Correlation of salivary immunoglobulin A with Body Mass Index and fat percentage in overweight/obese children]]> Abstract Obesity is considered a risk factor for periodontal health due to the low- grade inflammation promoted by the increased adipose tissue. Objective: This study aimed to determine correlations and associations between gingival inflammation (Simplified Oral Hygiene Index, and Gingival Index), salivary immunoglobulin A (s-IgA), and salivary parameters (salivary flow and osmolality) in normal-weight and overweight/obese children. Material and Methods: Ninety-one children, aged 6 to 12 years old (8.6±1.9 years), were divided into two groups according to their body mass index (BMI), circumferences, skinfold measurements and body fat percentage: normal- weight group (NWG; n =50) and overweight/obese group (OG; n =41). A calibrated examiner performed the clinical examination using the Simplified Oral Hygiene Index, Gingival Index, and salivary collection. Data analysis included descriptive statistics and association tests ( p &lt;0.05). Results: OG presented statistically higher s-IgA values compared with NWG, especially among the obese children ( p &lt;0.05). Significant positive correlations between s-IgA and salivary osmolality in OG ( p &lt;0.05), and between s-IgA and BMI values ( p &lt;0.05) and body fat percentage ( p &lt;0.05) were observed among all the children. Effect size varied from moderate for s-IgA values ( d =0.57) to large for BMI ( d =2.60). Conclusion: Gingival inflammation and salivary parameters were similar for NWG and OG; however, s-IgA presented higher values in OG, with correlations between BMI and body fat percentage. <![CDATA[Effects of cyclosporin, nifedipine and phenytoin on gingival myofibroblast transdifferentiation in monkeys]]> Abstract Objective: Myofibroblasts have been associated with the development of several pathologic fibrotic conditions. This longitudinal study aims to assess the proliferative and antiapoptotic effects of cyclosporin, nifedipine and phenytoin on gingival connective tissue cells of nonhuman primate, as well as to analyze a possible role of myofibroblasts in gingival overgrowth. Materials and Methods: Gingival samples from the right superior canine area were obtained from 12 male monkeys ( Sapajus spp ) to comprise the control group. After one week, the animals were randomly assigned to three groups, which received daily oral doses of cyclosporin, nifedipine or phenytoin for 120 days. Gingival samples were collected from the left superior canine area of two animals of each group at 52 and 120 days. Histological sections were stained with hematoxylin and eosin, and immunoreacted against α-SMA, Ki- 67 and bcl-2. Results: α-SMA immunoreaction was negative in the control and experimental groups. Similarly, no difference between groups concerning immunostaining against Ki-67 and bcl-2 was observed in connective tissue cells. Conclusion: Based on this methodology, it may be concluded that gingival overgrowths induced by cyclosporin, nifedipine and phenytoin are not associated with neither myofibroblast transdifferentiation, proliferation nor apoptosis of gingival connective cells in monkeys. <![CDATA[The link between ankylosing spondylitis and oral health conditions: two nested case-control studies using data of the UK Biobank]]> Abstract Ankylosing Spondylitis (AS) is an inflammatory rheumatic disease that affects the axial skeleton and the sacroiliac joints. Recent studies investigated the link between AS and oral diseases, particularly periodontitis. Others suggested that periodontitis may have a role in the pathogenesis of rheumatic diseases. Objective: The aim of this study is to investigate the association between AS and oral conditions. Material and Methods: This research was conducted using the UK Biobank Resource under Application Number 26307. The UK Biobank recruited around 500000 participants throughout Great Britain. Clinical records were available for 2734 participants. Two case-control studies were conducted based on whether AS was self-reported or clinically diagnosed. Oral conditions were identified using self-reported reports of oral ulcers, painful gums, bleeding gums, loose teeth, toothache, and dentures. The association between AS and oral conditions was assessed using logistic regression adjusted for age, gender, educational level, smoking status, alcohol consumption, and body mass index. Results: A total of 1307 cases and 491503 control participants were eligible for the self-reported AS study. The mean age was 58 years for the cases [7.5 standard deviation (SD)] and 57 years for the control groups (8.1 SD). Also, 37.1% of the cases and 54.2% of the control participants were females. Among the oral conditions, only oral ulcers were strongly associated with AS [1.57 adjusted odds ratio (OR); 95% confidence interval (CI) 1.31 to 1.88]. For the study of clinically diagnosed AS, 153 cases and 490351 control participants were identified. The mean age for both cases and control groups was 57 years; 7.6 SD for the cases and 8.1 for the control group. Females corresponded to 26.1% of the cases, and 54.2% of the control participants. Clinically diagnosed AS was associated with self-reported oral ulcers (2.17 adjusted OR; 95% CI 1.33 to 3.53). Conclusion: Self-reported and clinically diagnosed AS populations have increased risk of reporting oral ulcers. Further investigations are required to assess the link between a specific type of oral condition and AS. <![CDATA[Effects of in-office bleaching agent combined with different desensitizing agents on enamel]]> Abstract Objective: To analyze color change, microhardness and chemical composition of enamel bleached with in-office bleaching agent with different desensitizing application protocols. Materials and Methods: One hundred and seventeen polished anterior human enamel surfaces were obtained and randomly divided into nine groups (n = 13). After recording initial color, microhardness and chemical composition, the bleaching treatments were performed as G1: Signal Professional White Now POWDER&amp;LIQUID FAST 38% Hydrogen peroxide(S); G2: S+Flor Opal/0.5% fluoride ion(F); G3: S+GC Tooth Mousse/Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) paste(TM); G4: S+UltraEZ/3% potassium nitrate&amp;0.11% fluoride(U); G5: S+Signal Professional SENSITIVE PHASE 1/30% Nano-Hydroxyapatite (n-HAP) suspension(SP); G6: S-F mixture; G7: S-TM mixture; G8: S-U mixture; G9: S-SP mixture. Color, microhardness and chemical composition measurements were repeated after 1 and 14 days. The percentage of microhardness loss (PML) was calculated 1 and 14 days after bleaching. Data were analyzed with ANOVA, Welch ANOVA, Tukey and Dunnett T3 tests (p&lt;0.05). Results: Color change was observed in all groups. The highest ΔE was observed at G7 after 1 day, and ΔE at G8 was the highest after 14 days (p&lt;0.05). A decrease in microhardness was observed in all groups except G6 and G7 after 1 day. The microhardness of all groups increased after 14 days in comparison with 1 day after bleaching (p&gt;0.05). PML was observed in all groups except G6 and G7 after bleaching and none of the groups showed PML after 14 days. No significant changes were observed after bleaching at Ca and P levels and Ca/P ratios at 1 or 14 days after bleaching (p&gt;0.05). F mass increased only in G2 and G6, 1 day after bleaching (p&lt;0.05). Conclusions: The use of desensitizing agents containing fluoride, CPP-ACP, potassium nitrate or n-HAP after in-office bleaching or mixed in bleaching agent did not inhibit the bleaching effect. However, they all recovered microhardness of enamel 14 days after in-office bleaching. <![CDATA[Effect of topical ozonetherapy on gingival wound healing in pigs: histological and immuno-histochemical analysis]]> Abstract In this study, the effects of ozonetherapy on secondary wound healing were evaluated histologically and immuno-histochemically. Material and Methods: 8 healthy pigs were used in this study. Six wounds with 10 mm in diameter were created through the punch technique on the palatinal gingiva of each pig. Ozone gas was applied on only 3 wounds (test group) and the remaining 3 were left to natural healing (control group). Biopsy samples were taken from one of the wounds in each group on the third day, from another wound of each group on the seventh day, and from another one on the tenth day. Routine histological analysis and immuno-histochemical staining were performed to investigate transforming growth factor-beta (TGF-β) and (VEGF) expressions. Results: No statistical difference was found between the test and control groups in terms of collagen fibers, epithelial formation and inflammation scores. A VEGF expression found in the test group was statistically higher than control group samples taken on the 3rd and 7th day. There was no statistical difference between the test and control groups in terms of TGF-β expression on any of the sampling days. Conclusion: The topical application of ozone gas could be effective in the early stages of wound healing by increasing the amount of VEGF expression. Clinical Relevance: Topical application of ozone gas may be effective in the early stages of oral wound healing. <![CDATA[Inhibitory effect of reduced graphene oxide-silver nanocomposite on progression of artificial enamel caries]]> Abstract The use of antimicrobial agents is an efficient method to prevent dental caries. Also, nanometric antibacterial agents with wide antibacterial spectrum and strong antibacterial effects can be applied for prevention of dental caries. Objectives: The aim of this study was to evaluate the inhibitory effect of reduced graphene oxide-silver nanoparticles (rGO/Ag) composite on the progression of artificial enamel caries in a Streptococcus mutans biofilm model. Material and Methods: Enamel specimens from bovine incisors were divided into eight treatment groups (n = 13), as follows: group 1 was inoculated with S. mutans grown in Brain Heart Infusion containing 1% sucrose (1% BHIS), as negative control; groups 2-4 were inoculated with S. mutans grown in the presence of different rGO/Ag concentrations (0.08, 0.12, 0.16 mg/mL) + 1% BHIS; group 5-7 were inoculated with S. mutans grown in the presence of different agents (0.16 mg/mL reduced graphene oxide, 0.16 mg/mL silver nanoparticles, 10 ppm NaF) + 1% BHIS; group 8 was mixed with 1% BHIS, without inoculation. Artificial enamel carious lesions were produced by S. mutans biofilm model for 7 days. Confocal laser scanning microscopy and atomic force microscopy were used to analyze roughness and morphology of the enamel surface. Polarized light microscopy and confocal laser scanning microscopy were employed to measure the lesion depth and the relative optical density (ROD) of the demineralized layer. Results: Compared with the control groups, the rGO/Ag groups showed: (a) reduced enamel surface roughness; (b) much smoother and less eroded surfaces; (c) shallower lesion depth and less mineral loss. Conclusion: As a novel composite material, rGO/Ag can be a promising antibacterial agent for caries prevention. <![CDATA[Effect of fluoride application during radiotherapy on enamel demineralization]]> Abstract Radiation-related caries are one the most undesired reactions manifested during or after head and neck radiotherapy. Fluoride application is an important strategy to reduce demineralization and enhance remineralizaton. Objective: To evaluate the effect of the topical application of fluoride during irradiation on dental enamel demineralization. Material and Methods: Thirty molars were randomly divided into three groups: Non-irradiated (NI), Irradiated (I), Irradiated with fluoride (IF). Each group was subdivided according to the presence or absence of pH-cycling (n=5). In the irradiated groups, the teeth received 70 Gy. The enamel's chemical composition was measured using Fourier Transform Infrared Spectrometry (organic matrix/mineral ratio - M/M and relative carbonate content - RCC). Vickers microhardness (VHN) and elastic modulus (E) were evaluated at three depths (surface, middle and deep enamel). Scanning electron microscopy (SEM) was used to assess the enamel's morphology. Results: The FTIR analysis (M/M and RCC) showed significant differences for irradiation, pH-cycling and the interaction between factors (p&lt;0.001). Without pH-cycling, IF had the lowest organic matrix/mineral ratio and relative carbonate content. With pH-cycling, the organic matrix/mineral ratio increased and the relative carbonate content decreased, except for IF. VHN was influenced only by pH-cycling (p&lt;0.001), which generated higher VHN values. ANOVA detected significant differences in E for irradiation (p&lt;0.001), pH-cycling (p&lt;0.001) and for the interaction between irradiation and pH-cycling (p&lt;0.001). Increased E was found for group I without pH-cycling. With pH-cycling, groups I and IF were similar, and showed higher values than NI. The SEM images showed no morphological changes without pH-cycling. With pH-cycling, fluoride helped to maintain the outer enamel's morphology. Conclusions: Fluoride reduced mineral loss and maintained the outer morphology of irradiated and cycled enamel. However, it was not as effective in preserving the mechanical properties of enamel. Radiotherapy altered the enamel's elastic modulus and its chemical composition. <![CDATA[Surface and vertical dimensional changes of mineral trioxide aggregate and biodentine in different environmental conditions]]> Abstract Surface changes in biological environments are critical for the evaluation of physical and biological activity of biomaterials. Objective: This study investigated surface alterations of calcium silicate-based cements after exposure to different environments. Material and Methods: Forty-eight cylindrical cavities were prepared on root surfaces. The cavities were filled using ProRoot MTA or Biodentine and assigned to four subgroups (n=6): dry, wet, acidic, and blood. Surface topographies were evaluated using an optical profilometer for 28 days, and the roughness of the material surfaces was quantified. Vertical dimensional change was measured by determining the height difference between the material surface and the flat tooth surface. Data were compared with a two-way repeated measures ANOVA and Bonferroni tests. Results: In dry condition, the surface roughness of MTA or Biodentine was constant up to 3 days (p&gt;0.05) but decreased after 28 days (p&lt;0.05). In dry condition, ProRoot MTA presented constant surface level through time, while Biodentine showed decreased surface level after 28 days. In wet condition, the roughness and the surface levels of both materials increased after 1 day (p&lt;0.05). Neither the surface roughness nor the levels of the materials showed significant changes in acidic conditions (p&gt;0.05). Both materials showed the highest roughness in blood conditions on the 1st day (p&lt;0.05), while the surface roughness in blood decreased dramatically after 28 days. The roughness of Biodentine was higher in wet conditions up to 3 days compared with ProRoot MTA (p&lt;0.05). Likewise, in blood condition, Biodentine showed higher roughness on the 28th day than ProRoot MTA (p&lt;0.05). Conclusions: Dry, wet, and blood conditions had a time-dependent effect on the surface roughness and vertical dimensional changes of the materials. However, acidic conditions did not affect the roughness and the surface level of the materials. <![CDATA[Proteomic analysis of the acquired enamel pellicle formed on human and bovine tooth: a study using the Bauru <em>in situ</em> pellicle model (BISPM)]]> Abstract The acquired enamel pellicle (AEP) is an organic film, bacteria-free, formed in vivo as a result of the selective adsorption of salivary proteins and glycoproteins to the solid surfaces exposed to the oral environment. Objective: This study aimed to compare the proteomic profile of AEP formed in situ on human and bovine enamel using a new intraoral device (Bauru in situ pellicle model - BISPM). Material and Methods: One hundred and eight samples of human and bovine enamel were prepared (4×4 mm). Nine subjects with good oral conditions wore a removable jaw appliance (BISPM) with 6 slabs of each substrate randomly allocated. The AEP was formed during the morning, for 120 minutes, and collected with an electrode filter paper soaked in 3% citric acid. This procedure was conducted in triplicate and the pellicle collected was processed for analysis by LC-ESI-MS/MS. The obtained mass spectrometry MS/MS spectra were searched against human protein database (SWISS-PROT). Results: The use of BISPM allowed the collection of enough proteins amount for proper analysis. A total of 51 proteins were found in the AEP collected from the substrates. Among them, 15 were common to both groups, 14 were exclusive of the bovine enamel, and 22 were exclusive of the human enamel. Proteins typically found in the AEP were identified, such as Histatin-1, Ig alpha-1, Ig alpha 2, Lysozyme C, Statherin and Submaxillary gland androgen-regulated protein 3B. Proteins not previously described in the AEP, such as metabolism, cell signaling, cell adhesion, cell division, transport, protein synthesis and degradation were also identified. Conclusion: These results demonstrate that the proteins typically found in the AEP appeared in both groups, regardless the substrate. The BISPM revealed to be a good device to be used in studies involving proteomic analysis of the AEP. <![CDATA[Effect of diode laser irradiation on the bond strength of polymerized non-simplified adhesive systems after 12 months of water storage]]> Abstract Objectives: The aim of this in vitro study was to evaluate the bonding strength of non-simplified dentin bonding systems (DBS) to dentin irradiated with a diode laser (970 nm) immediately and after 12 months of water storage following either primer or bond application. Material and methods: The experimental design included three different factors: DBS type [AdperTM Scotchbond Multipurpose (MP) and Clearfil™ SE Bond (CSE)], irradiation [without irradiation - control (C), irradiation after primer application (AP), and irradiation after bond application (AB)], and time [initial (I) and after 12 months of water storage (12 m)]. Sixty sound human third molars (n = 10) were obtained, and their flat occlusal dentin areas were prepared and standardized. Laser irradiation was performed in the contact mode perpendicular to the dental surface over an automatically selected scanning area at a pulse energy of 0.8 W, frequency of 10 Hz, and energy density of 66.67 J/cm2. After 7 days of treatment, the specimens were cut, and half of them were subjected to microtensile testing (500 N/0.05 mm/min), whereas the remaining sticks were examined after 12 months of water storage. The obtained data were analyzed by three-way analysis of variance (ANOVA) followed by a Tukey test (p&lt;0.05). The observed fracture modes were investigated using a portable digital microscope with a magnification of 40x. Results: Among the utilized DBS, MP generally exhibited higher bond strengths, but did not always differ from CSE under similar conditions. The irradiation factor was statistically significant only for the MP/AB groups. After 12 months of storage, all groups demonstrated a significant reduction in the bond strength, whereas the results of fracture analysis showed a predominance of the adhesive type. Conclusions: The laser treatment of non-simplified DBS was not able to stabilize their bonding characteristics after 12 months. <![CDATA[Development and characterization of a novel bulk-fill elastomeric temporary restorative composite]]> Abstract Objectives: This study investigated the physical and mechanical properties, antibacterial effect and biocompatibility of novel elastomeric temporary resin-based filling materials (TFMs) containing zinc methacrylate (ZM). Material and Methods: Experimental TFMs were prepared by mixing the zinc methacrylate with monomer, co-monomer, photoinitiator and fillers. A ZM concentration of 0 (control), 0.5% (Z0.5); 1% (Z1), 2% (Z2), or 5% (ZM5) wt% was added to the TFMs. Fermit-N (F) was used for comparison with the experimental material. Microleakage, water sorption/solubility, degree of conversion, depth of cure, ultimate tensile strength, and hardness were determined and compared. A modified direct contact test (DCT) with Enterococcus faecalis and a Streptococcus mutans’ biofilm accumulation assay was carried out to evaluate the antimicrobial effect and cytotoxicity of the assay. Statistical comparisons were performed (α=5%). Results: The results showed that the physical and mechanical properties of the experimental TFMs with ZM are comparable with the properties of the commercial reference and some properties were improved, such as lower microleakage and water sorption, and higher ultimate tensile strength values. TFMs with ZM killed E. faecalis only after 1 h. Biofilm development of S. mutans was not affected by the inclusion of ZM in the experimental TFMs. Conclusions: The present findings suggest that the physical, mechanical and biological properties of the experimental TFMs with ZM are comparable with the properties of the commercial reference. However, some properties were improved, such as lower microleakage and water sorption, and higher ultimate tensile strength values. <![CDATA[Evaluation of pain perception during orthodontic debonding of metallic brackets with four different techniques]]> Abstract Objective The aim of this study was to evaluate patients’ pain levels during four different debonding procedures. The null hypothesis was that the pain perception of the patients undergoing four different debonding applications was not statistically significant different. Material and Methods One hundred and twenty orthodontic patients who underwent orthodontic debonding were included in this study. The patients were randomly divided into 4 groups according to technique used in the patients. Debonding groups were as follows: Group 1) Conventional debonding group, Group 2) Medication group (acetaminophen was given 1 hour before debonding), Group 3) Soft bite wax group, and Group 4) Soft acrylic bite wafer group. The patients’ levels of anxiety and fear of pain were evaluated before debonding, and Numerical Rating Scale (NRS) was applied to evaluate their pain perception during debonding. Mann-Whitney U and Kruskal–Wallis tests were used to evaluate non-normally distributed data. Categorical data analysis were carried by chi-square and McNemar tests. The significance level was set at p&lt;0.05. Results Anxiety scores of the patients were not statistically significant between both genders and debonding groups. In the quadrants in which the patients were perceived, the highest pain level was in the left side of the mandible. The teeth in which the highest pain level was perceived were the lower left and upper right lateral incisors. Although there was no statistically significant difference among the pain scores of the patients in each group, quadrant scores of female patients showed significant differences, being the lowest scores in the soft bite wax group. Conclusions Majority of the patients had no fear of pain before debonding. Pain levels of the patients in the conventional debonding group were not significantly different from those of the other groups, except quadrant scores of females in the soft bite wax group. The null hypothesis was accepted. <![CDATA[Efficacy of sonic and ultrasonic irrigation devices in the removal of debris from canal irregularities in artificial root canals]]> Abstract Objective To evaluate the efficacy of different sonic and ultrasonic devices in the elimination of debris from canal irregularities in artificial root canals. Materials and Methods A resin model of a transparent radicular canal filled with dentin debris was used. Five groups were tested, namely: Group 1 – ultrasonic insert 15.02; Group 2 – ultrasonic insert 25/25 IRRI K; Group 3 – ultrasonic insert 25/25 IRRI S; Group 4 – sonic insert 20/28 Eddy on a vibrating sonic air-scaler handpiece; Group 5 – 20.02 K-file inserted on a Safety M4 handpiece. Two different irrigants (5% sodium hypochlorite and 17% EDTA) and 3 different times of activation (20, 40, and 60 seconds) were tested. Means and standard deviations were calculated and statistically analyzed with the Kruskal-Wallis and Wilcoxon tests (p&lt;0.05). Results No statistically significant differences were found between the two irrigants used. Group 4 removed more debris than the other groups (p&lt;0.05). Groups 1, 2, and 3 removed more debris than group 5 (p&lt;0.05). A statistically significant difference (p&lt;0.05) was found for the time of activation in all groups and at all canal levels, except between 40 and 60 seconds in group 4 at coronal and middle third level (p&gt;0.05). Conclusions No significant differences were found between 5% sodium hypochlorite and 17% EDTA. When the time of activation rises, the dentin debris removal increases in all groups. Both sonic and ultrasonic activation demonstrate high capacity for dentin debris removal. <![CDATA[Effect of radiant exposure and UV accelerated aging on physico-chemical and mechanical properties of composite resins]]> Abstract Currently, there is no consensus in terms of defining the minimum radiant exposure values necessary for achieving adequate properties of composite resin. In addition, the long-term influence that radiant exposure has on the properties of composite resins is still questionable. Objective: The objective of this study was to evaluate the effect of radiant exposure and UV accelerated aging on the physico-chemical and mechanical properties of micro-hybrid and nanofilled composite resins. Material and Methods: A nanofilled (Filtek Supreme; 3M ESPE) and a micro-hybrid composite resin (Filtek Z250; 3M ESPE) were investigated under different radiant exposures (3.75, 9, and 24 J/cm2) and UV accelerated aging protocols (0, 500, 1000, and 1500 aging hours). The degree of conversion (DC), flexural strength (FS), modulus (M), water sorption (WS), and solubility (WL) were evaluated. The results obtained were analyzed using two-way ANOVA and Tukey's test. Comparisons were performed using a significance level of α=0.05. Results: The DC, FS, and M were found to be significantly influenced by both radiant exposure and accelerated aging time. The DC and EM increased with radiant exposure in the no-aging group (0-hour aging) for both micro-hybrid and nanofilled composites, whereas no correlation was found after accelerated aging protocols. WS and WL of micro-hybrid and nanofilled composite resins were scarcely affected by radiant exposure (p&gt;0.05), whereas they were significantly reduced by accelerated aging (p&lt;0.001). Conclusions: Although increasing radiant exposure affected the degree of conversion and mechanical properties of micro-hybrid and nanofilled composites, no influence on the hydrolytic degradation of the material was observed. In contrast, UV accelerated aging affected both the physico-chemical and mechanical properties of the composites. <![CDATA[Comparison of <em>in vitro</em> erosion protocols in bovine teeth to simulate natural erosion lesion: analysis of mechanical properties and surface gloss]]> Abstract Objective The aim of this study was to compare two in vitro erosion protocols, in which one simulates in vivo conditions experienced by patients with gastroesophageal disorders or bulimia (HCl-pepsin protocol), and the other simulates the diet of an individual who consumes a high volume of erosive beverages (citric acid protocol). In addition, the mechanical properties and surface gloss of eroded human dentin were compared with those of sound human dentin. Materials and Methods Blocks of cervical dentin were used: sound human dentin (n=10), human dentin with erosive lesions (n=10), and bovine dentin (n=30). Twenty bovine blocks were subjected to either of two erosion protocols (n=10/protocol). In the first protocol, samples were demineralized using HCl-pepsin solution, then treated with trypsin solution. In the second protocol, samples were demineralized with 2% citric acid. Toothbrushing was performed in both protocols using a toothbrushing machine (15 s with a 150 g load). Ten bovine dentin blocks were not subjected to any erosive treatment. All samples of bovine and human dentin were analyzed to obtain Martens hardness values (MH), elastic modulus (Eit*) and surface gloss. One-way ANOVA and Tukey's test were performed to analyze the data (α=0.05). Results Sound human and eroded human dentin groups showed similar MH and Eit* values (p&gt;0.05); however, sound human dentin showed a higher surface gloss value when compared to eroded human dentin (p&lt;0.05). Sound bovine dentin and HCl-pepsin-treated bovine dentin treatments resulted in similar values for both MH and Eit* (p&gt;0.05), but HCl-pepsin-treated bovine dentin and citric acid-treated bovine dentin resulted in lower surface gloss than sound bovine dentin (p&lt;0.05). Conclusions The HCl-pepsin protocol modified bovine dentin properties that could be similar to those that occur on human dentin surfaces with erosive lesions. <![CDATA[Mechanical-physicochemical properties and biocompatibility of catechin-incorporated adhesive resins]]> Abstract Several anti-proteolytic dentin therapies are being exhaustively studied in an attempt to reduce dentin bond degradation and improve clinical performance and longevity of adhesive restorations. Objectives This study assessed the effect of epigallocatechin-3-gallate (EGCG) on long-term bond strength when incorporated into adhesives. Material and Methods Adhesive systems were formulated with EGCG concentrations of 0 wt%: (no EGCG; control); 0.5 wt% EGCG; 1.0 wt% EGCG, and 1.5 wt% EGCG. Flexural strength (FS), modulus of elasticity (ME), modulus of resilience (MR), compressive strength (CS), degree of conversion (DC), polymerization shrinkage (PS), percentage of water sorption (%WS), percentage of water solubility (%WL) and cytotoxicity properties were tested. Dentin microtensile bond strength (µTBS) was evaluated after 24 h and again after 6 months of water storage. The adhesive interface was analyzed using scanning electron microscopy (SEM). Results No significant differences were found among the groups in terms of FS, ME, MR, CS and PS. EGCG-doped adhesives increased the DC relative to the control group. EGCG concentrations of 1.0 wt% and 0.5 wt% decreased the WS of adhesives. WL decreased in all cases in which EGCG was added to adhesives, regardless of the concentration. EGCG concentrations of 1.0 wt% and 0.5 wt% reduced cytotoxicity. EGCG concentrations of 1.0 wt% and 0.5 wt% preserved µTBS after 6 months of storage, while 1.5 wt% EGCG significantly decreased µTBS. SEM: the integrity of the hybrid layer was maintained in the 0.5 wt% and 1.0 wt% EGCG groups. Conclusion EGCG concentrations of 1.0 wt% and 0.5 wt% showed better biological and mechanical performance, preserved bond strength and adhesive interface, and reduced cytotoxicity. <![CDATA[Shrinkage stress and elastic modulus assessment of bulk-fill composites]]> Abstract Bulk-fill composites were introduced in dentistry to accelerate clinical procedures while providing adequate outcomes. Concerns regarding the use of bigger composite increments rely on the polymerization shrinkage and shrinkage stress, which may generate gaps on the adhesive interface and result in a reduced success rate. Objective: To evaluate the polymerization shrinkage stress of different bulk-fill resin composites and their elastic modulus. Materials and Methods: Fourteen specimens were made for each of the nine different resin composites (seven with 12 mm3 and seven with 24 mm3): Surefill SDR flow (SDR), X-tra Base (XB), Filtek Bulk Fill Flowable (FBF), Filtek Z350XT Flow (Z3F); Tetric Evo Ceram Bulk Fill (TBF), X-tra Fil (XF), Filtek Bulk Fill (FBP), Admira Xtra Fusion (ADM) and Filtek Z350 XT (Z3XT). Linear shrinkage stress was evaluated for 300 s with the aid of a linear shrinkage device adapted to a Universal Testing Machine. For each composite group, seven additional specimens (2x2x25 mm) were made and Young's modulus was evaluated with a 3-point bending device adapted in a Universal Testing Machine with 0.5 mm/min crosshead speed and 50 KgF loading cell. Results: For 12 mm3 specimens, three-way ANOVA showed that only SDR and TBF generated lower stress after 20 s. Considering 300 s, TBF, SDR, and XF generated the lowest stress, followed by ADM, FBP, XB, and FBF, which were similar to Z3XT. Z3F generated the highest stress values for all time points. Considering 24 mm3 specimens after 20 s, all bulk fill composites generated lower stress than Z3XT, except XB. After 300 s, SDR, FBP, and ADM generated the lowest stress, followed by TBF and XF. For elastic modulus, one-way ANOVA showed that FBF, SDR, Z3F, and ADM presented the lowest values, followed by XB and TBF. FBP, Z3XT, and XF presented the highest elastic modulus among the evaluated composites. Conclusions: Bulk-fill resin composites presented equal to lower shrinkage stress generation when compared to conventional composites, especially when bigger increments were evaluated. Bulk-fill composites showed a wide range of elastic modulus values, but usually similar to “regular” composites. <![CDATA[Effect of ProRoot MTA<sup>®</sup> and Biodentine<sup>®</sup> on osteoclastic differentiation and activity of mouse bone marrow macrophages]]> Abstract Objectives This investigation aimed to assess the differentiation inhibitory effects of ProRoot MTA® (PMTA) and Biodentine® (BIOD) on osteoclasts originated from murine bone marrow macrophages (BMMs) and compare these effects with those of alendronate (ALD). Materials and Methods Mouse BMMs were cultured to differentiate into osteoclasts with macrophage colony-stimulating factor and receptor activator of NF-κB (RANKL), treated with lipopolysaccharide. After application with PMTA, BIOD, or ALD, cell toxicities were examined using WST-1 assay kit, and RANKL-induced osteoclast differentiation and activities were determined by resorption pit formation assay and tartrate-resistant acid phosphate (TRAP) staining. The mRNA levels of osteoclast activity-related genes were detected with quantitative real time polymerase chain reaction. Expressions of molecular signaling pathways were assessed by western blot. All data were statistically analyzed with one-way ANOVA and Tukey's post-hoc test (p&lt;0.05). Results Mouse BMMs applied with PMTA, BIOD, or ALD showed highly reduced levels of TRAP-positive osteoclasts. The BIOD treated specimens suppressed mRNA expressions of cathepsin K, TRAP, and c-Fos. Nonetheless, it showed a lower effect than PMTA or ALD applications. Compared with ALD, PMTA and BIOD decreased RANKL-mediated phosphorylation of ERK1/2 and IκBα. Conclusions PMTA and BIOD showed the inhibitory effect on osteoclast differentiation and activities similar to that of ALD through IκB phosphorylation and suppression of ERK signaling pathways. <![CDATA[Influence of surfactants addition on the properties of calcium hypochlorite solutions]]> Abstract Objectives The aim of this study was to evaluate the influence of surfactants 0.2% or 0.1% cetrimide (Cet) or 0.008% benzalkonium chloride (BAK) on 2.5% calcium hypochlorite (Ca(OCl)2), and compare to sodium hypochlorite (NaOCl), regarding the properties of pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity. Material and Methods The pH and free chlorine content were evaluated by digital pHmeter and by titration, respectively. Surface tension was measured by the platinum ring technique with a Du Noüy tensiometer. The solution's contact angle in human dentin surfaces was checked by Drop Shape Analyzer software. Bovine pulps were used for pulp dissolution analysis and the dissolving capacity was expressed by percent weight loss. Antimicrobial activity over Enterococcus faecalis was evaluated by the agar diffusion method. Results Surfactants addition to Ca(OCl)2 and NaOCl did not alter the pH, free chlorine content and pulp dissolution properties. Ca(OCl)2 had the highest surface tension among all tested solutions. When surfactants were added to Ca(OCl)2 and NaOCl, there was a significant reduction of surface tension and contact angle values. The addition of 0.2% or 0.1% Cet enhanced antimicrobial activity of both Ca(OCl)2 and NaOCl. Conclusion Surfactant addition to 2.5% Ca(OCl)2 has shown acceptable outcomes for pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity. Furthermore, the addition of 0.2% Cet showed better results for all tested properties. <![CDATA[Comparison between static and semi-dynamic models for microcosm biofilm formation on dentin]]> Abstract Microcosm biofilm has been applied to induce carious lesions in dentin. However, no study has been done to compare the impact of the type of model for providing nutrients to microcosm biofilm formation on dentin. Objective This study compared the performance of two kinds of models (static and semi-dynamic) on the biofilm formation and the development of dentin carious lesions. Material and Methods In both models, biofilm was produced using inoculum from pooled human saliva mixed with McBain saliva for the first 8 h (5% CO2 and 37°C). Afterwards, for the static model, the samples were placed in 24-wells microplate containing McBain saliva with 0.2% sucrose, which was replaced at 24 h. In the semi-dynamic model, the samples were submitted to artificial mouth system with continuous flow of McBain saliva with 0.2% sucrose (0.15 ml/min, 37°C) for 10 h a day (for the other 14 h, no flow was applied, similarly to the static model). After 5 days, biofilm viability was measured by fluorescence and dentin demineralization by transverse microradiography. Results Biofilm viability was significantly lower for the static compared with semi-dynamic model, while dentin demineralization was significantly higher for the first one (p&lt;0.05). The static model was able to produce a higher number of typical subsurface lesions compared with the semi-dynamic model (p&lt;0.05). Conclusions The type of model (static and semi-dynamic) applied in the microcosm biofilm may have influence on it's viability and the severity/profile of dentin carious lesions. <![CDATA[Distribution of depression, somatization and pain-related impairment in patients with chronic temporomandibular disorders]]> Abstract Objective the aim of this study was to describe the frequency of psychosocial diagnoses in a large sample of patients attending a tertiary clinic for treatment of temporomandibular disorders (TMD). Material and Methods six hundred and ninety-one patients who sought treatment for pain-related TMD were selected. Chronic pain-related disability (Graded Chronic Pain Scale, GCPS), depression [Symptoms Checklist-90 (SCL-90) scale for depression, DEP] and somatization levels (SCL-90 scale for non-specific physical symptoms, SOM) were evaluated through the Research Diagnostic Criteria for TMD (RDC/TMD) Axis II psychosocial assessment; TMD diagnoses were based on the Axis I criteria. Results the majority of patients presented a low disability or no disability at all, with only a small portion of individuals showing a severely limiting, high disability pain-related impairment (4.3%). On the other hand, abnormal scores of depression and somatization were high, with almost half of the individuals having moderate-to-severe levels of depression and three-fourths presenting moderate-to-severe levels of somatization. The prevalence of high pain-related disability (GCPS grades III or IV), severe/moderate depression and somatization was 14.3%, 44% and 74.1% respectively. Gender differences in scores of SCL-DEP (p=0.031) and SCL-SOM (p=0.001) scales were signficant, with females presenting the highest percentage of abnormal values. Conclusion patients with TMD frequently present an emotional profile with low disability, high intensity pain-related impairment, and high to moderate levels of somatization and depression. Therefore, given the importance of psychosocial issues at the prognostic level, it is recommended that clinical trials on TMD treatment include an evaluation of patients’ psychosocial profiles. <![CDATA[Effects of dodecacalcium hepta-aluminate content on the setting time, compressive strength, alkalinity, and cytocompatibility of tricalcium silicate cement]]> Abstract Objective This study aimed to investigate the effects of dodecacalcium hepta-aluminate (C12A7) content on some physicochemical properties and cytocompatibility of tricalcium silicate (C3S) cement using human dental pulp cells (hDPCs). Material and Methods High purity C3S cement was manufactured by a solid phase method. C12A7 was mixed with the cement in proportions of 0, 5, 8, and 10 wt% (C12A7-0, −5, −8, and −10, respectively). Physicochemical properties including initial setting time, compressive strength, and alkalinity were evaluated. Cytocompatibility was assessed with cell viability tests and cell number counts. Statistical analysis was performed by using one-way analysis of variance (ANOVA) and Tukey's test (p&lt;0.05). Results The initial setting time of C3S-based cement was shorter in the presence of C12A7 (p&lt;0.05). After 1 day, C12A7-5 showed significantly higher compressive strength than the other groups (p&lt;0.05). After 7 days, the compressive strength of C12A7-5 was similar to that of C12A7-0, whereas other groups showed strength lower than C12A7-0. The pH values of all tested groups showed no significant differences after 1 day (p&gt;0.05). The C12A7-5 group showed similar cell viability to the C12A7-0 group (p&gt;0.05), while the other experimental groups showed lower values compared to C12A7-0 group (p&lt;0.05). The number of cells grown on the C12A7-5 specimen was higher than that on C12A7-8 and −10 (p&lt;0.05). Conclusions The addition of C12A7 to C3S cement at a proportion of 5% resulted in rapid initial setting time and higher compressive strength with no adverse effects on cytocompatibility. <![CDATA[BK virus salivary shedding and viremia in renal transplant recipients]]> Abstract Objectives: This study aimed to verify the presence of polyomavirus BK (BKPyV) in the saliva of kidney transplant recipients and to correlate it with blood viremia. Material and Methods: We have conducted a cross-sectional study with a sample involving 126 renal transplant recipients. 126 samples of saliva and 52 samples of blood were collected from these patients. Detection and quantification of BKPyV were performed using a real-time PCR. To compare the presence of BKPyV in blood and saliva, the binomial proportion test was used. To verify associations between salivary shedding BKPyV and post-transplant periods (in months), the Mann-Whitney test was used. Spearman's correlation was used to correlate the viral load in the saliva with blood of kidney transplant recipients. Results: The mean age of the study group was 51.11±12.45 years old, and 69 participants (54.8%) were female, with a mean post-transplantation time of 4.80±6.04 months. BKPyV was quantified in several samples of saliva and blood, with medians of 1,108 cp/mL and 1,255 cp/mL, respectively. Only 16/52 (30.8%) participants presented BKPyV in blood, and 59/126 (46.8%) excreted the virus in saliva (p=0.004). BKPyV shedding was found in patients at a shorter post-transplantation period (3.86±5.25, p=0.100). A weak correlation was observed between viral quantification in saliva and blood (Spearman's correlation coefficient=0.193). Conclusion: The results of this study suggested that, although saliva excretes more BKPyV than blood, there is no reliable correlation between salivary shedding and blood viremia, showing two independent compartments of viral replication. <![CDATA[Assessment of anesthetic properties and pain during needleless jet injection anesthesia: a randomized clinical trial]]> Abstract Pain due to administration of local anesthetics is the primary reason for patients' fear and anxiety, and various methods are used to minimize it. This study aimed to measure the degree of pain during administration of anesthesia and determine the latency time and duration of pulpal anesthesia using two anesthetic methods in the maxilla. Materials and Methods: A randomized, single-blind, split-mouth clinical trial was conducted with 41 volunteers who required class I restorations in the maxillary first molars. Local anesthesia was administered with a needleless jet injection system (experimental group) or with a carpule syringe (control) using a 30-gauge short needle. The method of anesthesia and laterality of the maxilla were randomized. A pulp electric tester measured the latency time and duration of anesthesia in the second molar. Visual analogue scale (VAS) was used to measure the degree of pain during the anesthetic method. Data were tabulated and then analyzed by a statistician. The t-test was used to analyze the differences between the groups for basal electrical stimulation. Duration of anesthesia and degree of pain were compared using the Mann-Whitney test. A 5% significance level was considered. Results: There was no statistical difference in the basal electrical stimulation threshold (mA) and degree of pain between the two methods of anesthesia (p&gt;0.05). Latency time was 2 minutes for all subjects. The duration of pulpal anesthesia showed no statistical difference (minutes) between the two methods (p&lt;0.001), with a longer duration for the traditional method of anesthesia (median of 40 minutes). Conclusions: The two anesthetics methods did not differ concerning the pain experienced during anesthesia. Latency lasted 2 minutes for all subjects; the traditional infiltration anesthesia resulted in a longer anesthetic duration compared with the needleless jet injection. <![CDATA[Influence of mandibular and palatal intraoral appliances on erosion <em>in situ</em> study outcome]]> Abstract The standardization of in situ protocols for dental erosion is important to enable comparison between studies. Objective: Thus, the objectives of this study were to evaluate the influence of the location of in situ intraoral appliance (mandibular X palatal) on the extent of enamel loss induced by erosive challenges and to evaluate the comfort of the appliances. Material and Methods: One hundred and sixty bovine enamel blocks were selected according to their initial surface hardness and randomly divided into two groups: GI - palatal appliance and GII - mandibular appliance. Twenty volunteers wore simultaneously one palatal appliance (containing 4 enamel blocks) and two mandibular appliances (each one containing 2 enamel blocks). Four times per day during 5 days, the volunteers immersed their appliances in 0.01 M hydrochloric acid for 2 minutes, washed and reinserted them into the oral cavity for 2 hours until the next erosive challenge. After the end of the in situ phase, the volunteers answered a questionnaire regarding the comfort of the appliances. The loss of tissue in the enamel blocks was determined profilometrically. Data were statistically analyzed by paired t-test, Chi-square and Fisher's Exact Test (p&lt;0.05). Results: The enamel blocks allocated in palatal appliances (GI) presented significantly higher erosive wear when compared to the blocks fixed in mandibular appliances (GII). The volunteers reported more comfort when using the palatal appliance. Conclusions: Therefore, the palatal appliance is more comfortable and resulted in higher enamel loss compared to the mandibular one. <![CDATA[Evaluating clinical and laboratory effects of ozone in non-surgical periodontal treatment: a randomized controlled trial]]> Abstract Objective: This study aims to evaluate the clinical and biochemical (oxidative stress and pro-inflammatory mediators) effects of the gaseous ozone use accompanied by scaling and root planning (SRP) in periodontal treatment. Material and Methods: The study population consisted of 40 patients with chronic periodontitis (CP) randomly sorted into two groups of 20. The experimental group received SRP plus 3 watts gaseous ozone in two separate applications five days apart, whereas the control group received SRP plus placebo. Clinical periodontal parameters were assayed and saliva samples were taken before the initial and one month after the second treatment. Periodontal examination assessed plaque index (PI), gingival index (GI), probing depth, and clinical attachment level (CAL). Total antioxidant status (TAS), total oxidant status (TOS), nitric oxide (NO), 8-hydroxy-2'-deoxyguanosine (8-OHdG), myeloperoxidase (MPO), glutathione (GSH), malondialdehyde (MDA), and transforming growth factor-beta (TGF-β) levels were evaluated from saliva samples. Results: Changes following treatment in PI, GI, probing depth, and CAL scores were similar for both groups (p&gt;0.05). Of note, TGF-β levels were observed to be higher in the treatment group than in controls (p&lt;0.05). Changes in 8-OHdG, TAS, TOS, NO, MPO, GSH and MDA levels, however, were not significantly different between groups (p&gt;0.05). Conclusion: The findings of this study indicate that SRP plus gaseous ozone versus SRP alone does not correlate to a significant improvement in periodontal recovery. <![CDATA[Whitening toothpaste containing activated charcoal, blue covarine, hydrogen peroxide or microbeads: which one is the most effective?]]> Abstract The efficacy of whitening toothpastes is questionable and controversial. Clinicians, patients and researchers have expressed concern with whitening toothpastes due to the risk of wearing the dental structure and the potential for disappointment if the advertised cosmetic results are not achieved. Objective: This study compared the whitening performance of toothpastes with different whitening technologies after initial and continued use. Material and Methods: Ninety bovine incisors were stained using a concentrated solution of black tea. They were randomly distributed into 6 groups, according to the toothpaste whitening technology: activated charcoal (B&amp;W), blue covarine (WAD), hydrogen peroxide (LWA), microbeads (Oral B 3D White Perfection – 3DW) and optimized abrasives (XW4D). They were compared to a traditional toothpaste without a whitening agent (TA – control). Specimens underwent a brushing machine with controlled pressure, time and temperature. A calibrated examiner measured the color using a VITA-Classical scale before the first brushing cycle (T0), after the first brushing cycle (TI), and after a brushing cycle that simulates continuous use (TCU). Whitening performance was evaluated by the difference of shades (ΔSGU) between T0–TI and T0–TCU timepoints, using the Kruskal-Wallis and Dunn's non-parametric test. The Wilcoxon test was used to evaluate the cumulative effect (α=0.05). Results: Statistically significant differences were observed between toothpastes in both TI and TCU (p&lt;0.05). The time of use also had a significant effect (p&lt;0.05). Conclusion: Only WAD and 3DW showed whitening performance after the first use (TI). The greatest whitening performance after continuous use was obtained by WAD, followed by LWA and 3DW. The use of conventional toothpaste (TA) promotes no tooth whitening. Clinical relevance: Microbead abrasives (3DW) and blue covarine (WAD) were the active technology tested that presented the best global tooth whitening performance.