Scielo RSS <![CDATA[Journal of Applied Oral Science]]> vol. 24 num. 4 lang. es <![CDATA[SciELO Logo]]> <![CDATA[The impact of clinical use on the torsional behavior of Reciproc and WaveOne instruments]]> ABSTRACT Torsional overload is a fracture representative parameter for instruments in single-file techniques. Objective The aim of this study was to assess the influence of clinical use, in vivo, on the torsional behavior of Reciproc and WaveOne instruments considering the possibility that they degraded with use. Material and Methods Diameter at each millimeter, pitch length, and area at 3 mm from the tip were determined for both types of instruments. Twenty-four instruments, size 25, 0.08 taper, of each system were divided into two groups (n=12 each): Control Group (CG), in which new Reciproc (RC) and WaveOne Primary (WO) instruments were tested in torsion until rupture based on ISO 3630-1; and Experimental Group (EG), in which each new instrument was clinically used to clean and shape the root canals of one molar. After clinical use, the instruments were analyzed using optical and scanning electron microscopy and subsequently tested in torsion until fracture. Data were analyzed using one-way analysis of variance at a=.05. Results WO instruments showed significantly higher mean values of cross-sectional area A3 (P=0.000) and smaller pitch lengths than RC instruments with no statistically significant differences in the diameter at D3 (P=0.521). No significant differences in torsional resistance between the RC and WO new instruments (P=0.134) were found. The clinical use resulted in a tendency of reduction in the maximum torque of the analyzed instruments but no statistically significant difference was observed between them (P=0.327). During the preparation of the root canals, two fractured RC instruments and longitudinal and transversal cracks in RC and WO instruments were observed through SEM analysis. Conclusion After clinical use, no statistically significant reduction in the torsional resistance was observed. <![CDATA[Water interaction and bond strength to dentin of dye-labelled adhesive as a function of the addition of rhodamine B]]> ABSTRACT Objective This study investigated the effect of the fluorescent dye rhodamine B (RB) for interfacial micromorphology analysis of dental composite restorations on water sorption/solubility (WS/WSL) and microtensile bond strength to dentin (µTBS) of a 3-step total etch and a 2-step self-etch adhesive system. Material and Methods The adhesives Adper Scotchbond Multi-Purpose (MP) and Clearfil SE Bond (SE) were mixed with 0.1 mg/mL of RB. For the WS/WSL tests, cured resin disks (5.0 mm in diameter x 0.8 mm thick) were prepared and assigned into four groups (n=10): MP, MP-RB, SE, and SE-RB. For µTBS assessment, extracted human third molars (n=40) had the flat occlusal dentin prepared and assigned into the same experimental groups (n=10). After the bonding and restoration procedures, specimens were sectioned in rectangular beams, stored in water and tested after seven days or after 12 months. The failure mode of fractured specimens was qualitatively evaluated under optical microscope (x40). Data from WS/WSL and µTBS were assessed by one-way and three-way ANOVA, respectively, and Tukey’s test (α=5%). Results RB increased the WSL of MP and SE. On the other hand, WS of both MP and SE was not affected by the addition of RB. No significance in µTBS between MP and MP-RB for seven days or one year was observed, whereas for SE a decrease in the µTBS means occurred in both storage times. Conclusions RB should be incorporated into non-simplified DBSs with caution, as it can interfere with their physical-mechanical properties, leading to a possible misinterpretation of bonded interface. <![CDATA[Osseointegration aspects of placed implant in bone reconstruction with newly developed block-type interconnected porous calcium hydroxyapatite]]> ABSTRACT Artificial bone has been employed to reconstruct bone defects. However, only few reports on implant placement after block bone grafting exist. Objectives The purpose of this study was to evaluate the osseointegration of dental implant in bone reconstructions with interconnected porous calcium hydroxyapatite (IP-CHA). Material and Methods The IP-CHA cylinders (D; 4.3 mm, H; 10.0 mm) were placed into bone sockets in each side of the femurs of four male dogs. The IP-CHA on the right side was a 24-week sample. Twelve weeks after placement, a titanium implant was placed into a socket that was prepared in half of the placed IP-CHA cylinder on the right side. On the left side, another IP-CHA cylinder was placed as a 12-week sample. After another 12 weeks, the samples were harvested, and the bone regeneration and bone-implant contact (BIC) ratios were measured. Results New bone formation area was superior in the 24-week IP-CHA compared with the 12-week IP-CHA. BIC was not significantly different between IP-CHA and the parent sites. Osseointegration was detected around the implant in IP-CHA-reconstructed bone. Conclusion Our preliminary results suggest that IP-CHA may be a suitable bone graft material for reconstructing bones that require implant placement. <![CDATA[Effects of low-level laser therapy on stem cells from human exfoliated deciduous teeth]]> ABSTRACT Low-Level Laser Therapy stimulates the proliferation of a variety of types of cells. However, very little is known about its effect on stem cells from human exfoliated deciduous teeth (SHED). Objective This study aimed to evaluate the influence of different laser therapy energy densities on SHED viability and proliferation. Material and Methods SHED were irradiated according to the groups: I (1.2 J/cm2 - 0.5 mW – 10 s), II (2.5 J/cm2 – 10 mW – 10 s), III (3.7 J/cm2 – 15 mW – 10 s), IV (5.0 J/cm2 – 20 mW – 10 s), V (6.2 J/cm2 – 25 mW – 10 s), and VI (not irradiated – control group). Cell viability was assessed 6 and 24 h after irradiation measuring the mitochondrial activity and using the Crystal Violet assay. Cell proliferation was assessed after 24, 48, and 72 h of irradiation by SRB assay. Results MTT assay demonstrated differences from 6 to 24 hours after irradiation. After 24 h, groups I and IV showed higher absorbance values than those of control group. Crystal Violet assay showed statistically differences in the absorbance rate from 6 to 24 h after irradiation for groups III and VI. At 24 h after irradiation, Group III absorbance rate was greater than that of groups I, II, and IV. Group VI absorbance rate was greater than that of groups I and IV. SRB assay showed that the group I had higher rates than those of groups II, III, V, and VI, at 24 h after irradiation. After 48 h, group I exhibited the greatest cell proliferation rate followed by groups III, V, and VI. After 72 h, group III exhibited the lowest cell proliferation rate than those of groups II, IV, and V. Conclusions The Low-Level Laser Therapy energy densities used in this study did not cause loss of cell viability and stimulated SHED proliferation within the parameters described in this study. <![CDATA[Cytotoxicity and cytokine expression induced by silorane and methacrylate-based composite resins]]> ABSTRACT The successful use of composite resins in Dentistry depends on physicochemical properties, but also on the biological compatibility of resins, because of the close association between pulp and dentin. Objective The aim of this study was to evaluate cytotoxicity and cytokine production induced by light-cured or non-light-cured methacrylate-based and silorane composite resins in RAW 264.7 macrophages. Material and Methods Cells were stimulated with the extracts from light-cured or non-light-cured composite resins. After incubation for 24 h, cytotoxicity was assessed with the lactate dehydrogenase (LDH) and methyl thiazolyl tetrazolium (MTT) assays, and total protein was quantified using the Lowry method. TNF-α detection was examined with an enzyme-linked immunosorbent assay (ELISA) conducted with cell supernatants after cell stimulation for 6, 12, and 24 h. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test (α=0.05). Results KaloreTM and FiltekTM Silorane were cytotoxic with or without light curing (p&lt;0.05) after 24 h of incubation. KaloreTM stimulated the early production of TNF-α in comparison with control (p&lt;0.05), whereas FiltekTM Silorane did not affect TNF-α levels after 6 and 12 h (p&gt;0.05). However, after 24 h FiltekTM Silorane inhibited the production of TNF-α (p&lt;0.05). Conclusions KaloreTM and FiltekTM Silorane were cytotoxic regardless of light curing. The extract obtained from KaloreTM after 15 days of incubation stimulated the production of TNF-α, unlike that obtained from FiltekTM Silorane. <![CDATA[Characterisation and microleakage of a new hydrophilic fissure sealant - UltraSeal XT<sup>®</sup> hydro™]]> ABSTRACT Objectives The aim of this study was to characterise the new hydrophilic fissure sealant, UltraSeal XT® hydro™ (Ultradent Products, USA), and to investigate its in vitro resistance to microleakage after placement on conventionally acid etched and sequentially lased and acid etched molars. Material and Methods The sealant was characterised by Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Vickers indentation test. Occlusal surfaces of extracted human molars were either conventionally acid etched (n=10), or sequentially acid etched and laser irradiated (n=10). UltraSeal XT® hydro™ was applied to both groups of teeth which were then subjected to 2,500 thermocycles between 5 and 55°C prior to microleakage assessment by fuchsin dye penetration. Results UltraSeal XT® hydro™ is an acrylate-based sealant that achieved a degree of conversion of 50.6±2.2% and a Vickers microhardness of 24.2±1.5 under standard light curing (1,000 mWcm-2 for 20 s). Fluoride ion release is negligible within a 14-day period. SEM and EDX analyses indicated that the sealant comprises irregular submicron and nano-sized silicon-, barium-, and aluminium-bearing filler phases embedded in a ductile matrix. Laser preconditioning was found to significantly reduce microleakage (Mann-Whitney U test, p&lt;0.001). The lased teeth presented enhanced surface roughness on a 50 to 100 μm scale that caused the segregation and concentration of the filler particles at the enamel-sealant interface. Conclusion Laser preconditioning significantly decreased microleakage and increased enamel surface roughness, which caused zoning of the filler particles at the enamel-sealant interface. <![CDATA[Periodontal disease and inflammatory blood cytokines in patients with stable coronary artery disease]]> ABSTRACT Periodontal disease has been associated with elevations of blood cytokines involved in atherosclerosis in systemically healthy individuals, but little is known about this association in stable cardiovascular patients. The aim of this study was to assess the association between periodontal disease (exposure) and blood cytokine levels (outcomes) in a target population of patients with stable coronary artery disease (CAD). Material and Methods This cross-sectional study included 91 patients with stable CAD who had been under optimized cardiovascular care. Blood levels of IL-1β, IL-6, IL-8, IL-10, IFN-γ, and TNF-α were measured by Luminex technology. A full-mouth periodontal examination was conducted to record probing depth (PD) and clinical attachment (CA) loss. Multiple linear regression models, adjusting for gender, body mass index, oral hypoglycemic drugs, smoking, and occurre:nce of acute myocardial infarction were applied. Results CAD patients that experienced major events had higher concentrations of IFN-γ (median: 5.05 pg/mL vs. 3.01 pg/mL; p=0.01), IL-10 (median: 2.33 pg/mL vs. 1.01 pg/mL; p=0.03), and TNF-α (median: 9.17 pg/mL vs. 7.47 pg/mL; p=0.02). Higher numbers of teeth with at least 6 mm of CA loss (R2=0.07) and PD (R2=0.06) were significantly associated with higher IFN-γ log concentrations. Mean CA loss (R2=0.05) and PD (R2=0.06) were significantly related to IL-10 concentrations. Elevated concentrations of TNF-α were associated with higher mean CA loss (R2=0.07). Conclusion Periodontal disease is associated with increased systemic inflammation in stable cardiovascular patients. These findings provide additional evidence supporting the idea that periodontal disease can be a prognostic factor in cardiovascular patients. <![CDATA[Immunoexpression of cleaved caspase-3 shows lower apoptotic area indices in lip carcinomas than in intraoral cancer]]> ABSTRACT Objective This study aimed to evaluate apoptosis by assessing cleaved caspase-3 immunoexpression in hyperplastic, potentially malignant disorder (PMD), and malignant tumors in intraoral and lower lip sites. Material and Methods A retrospective study using paraffin blocks with tissues from patients with inflammatory fibrous hyperplasia (IFH), actinic cheilitis, oral leukoplakia, lower lip and intraoral squamous cell carcinoma (SCC) was performed. The tissues were evaluated by immunohistochemical analysis with anti-cleaved caspase-3 antibody. Apoptotic area index was then correlated with lesion type. Results From 120 lesions assessed, 55 (46%) were cleaved caspase-3-positive. The SCC samples (n=40) had the highest apoptotic area indices (n=35; 87.5%). Significant differences were detected between SCCs and PMDs (p=0.0003), as well as SCCs and IFHs (p=0.001), regarding caspase-3 immunopositivity. Carcinomas of the lower lip had lower apoptotic area indices than intraoral cancer (p=0.0015). Conclusions Cleaved caspase-3 immunoexpression showed differences in oral SCCs and PMDs and demonstrated a distinct role of apoptosis in carcinogenesis of intraoral and lower lip cancer. In future, the expression of cleaved caspase-3 with other target molecules in oral cancer may be helpful in delineating the prognosis and treatment of these tumors. <![CDATA[MMP1-1607 polymorphism increases the risk for periapical lesion development through the upregulation MMP-1 expression in association with pro-inflammatory milieu elements]]> ABSTRACT Increased matrix metalloproteinases (MMPs) activity is a hallmark of periapical granulomas. However, the factors underlying the MMPs expression modulation in healthy and diseased periapical tissues remains to be determined. Objective In this study, we evaluated the association between the MMP1-1607 polymorphism (rs1799750) and pro-inflammatory milieu elements with MMP-1 mRNA levels in vivo. Material and Methods MMP1-1607 SNP and the mRNA levels of MMP-1, TNF-a, IFN-g, IL-17A, IL-21, IL-10, IL-4, IL-9, and FOXp3 were determined via RealTimePCR in DNA/RNA samples from patients presenting periapical granulomas (N=111, for both genotyping and expression analysis) and control subjects (N=214 for genotyping and N=26 for expression analysis). The Shapiro-Wilk, Fisher, Pearson, Chi-square ordinal least squares regression tests were used for data analysis (p&lt;0.05 was considered statistically significant). Results The MMP1-1607 1G/2G and 1G/2G+2G/2G genotypes were significantly more prevalent in the patients than in controls, comprising a risk factor for periapical lesions development. MMP-1 mRNA levels were higher in periapical lesions than in healthy periodontal ligament samples, as well as higher in active than in inactive lesions. The polymorphic allele 2G carriers presented a significantly higher MMP-1 mRNA expression when compared with the 1G/1G genotype group. The ordered logistic regression demonstrated a significant correlation between the genetic polymorphism and the expression levels of MMP-1. Additionally, the pro- and anti-inflammatory cytokines IL-17A, IFN-g, TNF-a, IL-21, IL-10, IL-9, and IL-4 were significant as complementary explanatory variables of MMP-1 expression. Conclusion The MMP1-1607 SNP was identified as a risk factor for periapical lesions development, possibly due to its association with increased MMP-1 mRNA levels in periapical lesions. The MMP-1 expression is also under the control of the inflammatory milieu elements, being the cytokines TNF-a, IL-21, IL-17A, and IFN-g associated with increased MMP-1 levels in periapical lesions, while IL-10, IL-9, or IL-4 presented an inverse association. <![CDATA[Aging impairs osteoblast differentiation of mesenchymal stem cells grown on titanium by favoring adipogenesis]]> ABSTRACT Aging negatively affects bone/titanium implant interactions. Our hypothesis is that the unbalance between osteogenesis and adipogenesis induced by aging may be involved in this phenomenon. Objective We investigated the osteoblast and adipocyte differentiation of mesenchymal stem cells (MSCs) from young and aged rats cultured on Ti. Material and Methods Bone marrow MSCs derived from 1-month and 21-month rats were cultured on Ti discs under osteogenic conditions for periods of up to 21 days and osteoblast and adipocyte markers were evaluated. Results Cell proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization and gene expression of RUNX2, osterix, ALP, bone sialoprotein, osteopontin, and osteocalcin were reduced in cultures of 21-month rats compared with 1-month rats grown on Ti. Gene expression of PPAR-γ , adipocyte protein 2, and resistin and lipid accumulation were increased in cultures of 21-month rats compared with 1-month rats grown on the same conditions. Conclusions These results indicate that the lower osteogenic potential of MSCs derived from aged rats compared with young rats goes along with the higher adipogenic potential in cultures grown on Ti surface. This unbalance between osteoblast and adipocyte differentiation should be considered in dental implant therapy to the elderly population. <![CDATA[Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography]]> ABSTRACT Objective The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques. Material and Methods Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light beam of OCT (Thorlabs), allowing measurement in 200 µm intervals. Restorations were cemented with a self-adhesive cement resin (SmartCem2, Dentsply), and then marginal adaptations were again measured with OCT. Mean values were statistically compared by using independent-samples t-test and paired samples t-test (p&lt;0.05), before and after cementation. Results Direct inlays presented statistically smaller marginal discrepancy values than indirect inlays, before (p=0.00001442) and after (p=0.00001466) cementation. Marginal discrepancy values were increased for all restorations after cementation (p=0.00008839, p=0.000000952 for direct and indirect inlays, respectively). The mean marginal discrepancy value of the direct group increased from 56.88±20.04 µm to 91.88±31.7 µm, whereas the indirect group increased from 107.54±35.63 µm to 170.29±54.83 µm. Different techniques are available to detect marginal adaptation of restorations, but the OCT system can give quantitative information about resin cement thickness and its interaction between tooth and restoration in a nondestructive manner. Conclusions Direct inlays presented smaller marginal discrepancy than indirect inlays. The marginal discrepancy values were increased for all restorations that refer to cement thickness after cementation. <![CDATA[Influence of resin cement shade on the color and translucency of ceramic veneers]]> ABSTRACT Objective This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3) layer on color change, translucency parameter (TP), and chroma of low (LT) and high (HT) translucent reinforced lithium disilicate ceramic laminates. Material and Methods One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent) was applied to 1-mm thick ceramic discs to create thin RC films (100 µm thick) under the ceramics. The RC was exposed to light from a LED curing unit. Color change (ΔE) of ceramic discs was measured according to CIEL*a*b* system with a standard illuminant D65 in reflectance mode in a spectrophotometer, operating in the light range of 360-740 nm, equipped with an integrating sphere. The color difference between black (B) and white (W) background readings was used for TP analysis, while chroma was calculated by the formula C*ab=(a*2+b*2)½. ΔE of 3.3 was set as the threshold of clinically unacceptable. The results were evaluated by two-way ANOVA followed by Tukey's post hoc test. Results HT ceramics showed higher ΔE and higher TP than LT ceramics. A3-shade RC promoted higher ΔE than A1-shade cement, regardless of the ceramic translucency. No significant difference in TP was noted between ceramic discs with A1- and those with A3-shade cement. Ceramic with underlying RC showed lower TP than discs without RC. HT ceramics showed lower chroma than LT ceramics, regardless of the resin cement shade. The presence of A3-shade RC resulted in higher chroma than the presence of A1-shade RC. Conclusions Darker underlying RC layer promoted more pronounced changes in ceramic translucency, chroma, and shade of high translucent ceramic veneers. These differences may not be clinically differentiable. <![CDATA[Higher prevalence and gene amplification of HPV16 in oropharynx as compared to oral cavity]]> ABSTRACT Objective The objective of this study was to clarify differences regarding HPV16 infection and gene amplification between the oral cavity and oropharynx in healthy individuals. Material and Methods The subjects were 94 healthy asymptomatic individuals (41 males, 53 females; mean age 58.6 years, range 16-97 years) who visited the Department of Oral and Maxillofacial Reconstructive Surgery of the Hiroshima University Hospital from 2014 to 2015. Oral epithelial cells were collected from oral rinse and pharynx gargle samples and placed in saline. The human endogenous retrovirus gene ERV3-1 was used as a reference to estimate the number of human cells in each sample. DNA samples were extracted from approximately 10,000 human cells and tested for HPV16 DNA by PCR using a type-specific primer. Similarly, we analyzed the HPV16 viral copy number in HPV16-positive cases using real-time PCR to examine genomic amplification. Results The percentage of HPV16-positive cases was higher in the gargle (28.7%) as compared to the rinse (16.0%) samples. In the oral rinse samples, males (26.8%) showed a significantly higher rate of HPV16 than females (7.5%) (P=0.021). Importantly, in older subjects (aged 60-89 years), gargle samples showed a significantly higher rate of HPV16 (33.3%) than oral rinse samples (13.7%) (P=0.034). The average number of viral copies was approximately 8 times higher in the gargle than in the oral rinse samples (0.16±0.27 vs. 1.35±1.26 copy numbers per cell), a significant difference (P&lt;0.001). Conclusion Our findings suggest that the oropharynx is more susceptible to HPV16 infection as compared to the oral cavity, while HPV16 gene amplification is also more commonly found in the oropharynx. <![CDATA[Effect of silver nanoparticles on the physicochemical and antimicrobial properties of an orthodontic adhesive]]> ABSTRACT Orthodontic treatment with fixed brackets plays a major role on the formation of white spot lesions. Objective This study aimed to incorporate silver nanoparticle solutions (AgNP) in an orthodontic adhesive and evaluate its physicochemical and antimicrobial properties. Material and Methods Silver nanoparticle solutions were added to a commercial adhesive in different concentrations (w/w): 0%, 0.11%, 0.18%, and 0.33%. Shear bond strength (SBS) test was performed after bonding metal brackets to enamel. Raman spectroscopy was used to analyze in situ the degree of conversion (DC) of the adhesive layer. The surface free energy (SFE) was evaluated after the measurement of contact angles. Growth inhibition of Streptococcus mutans in liquid and solid media was determined by colony-forming unit count and inhibition halo, respectively. One-way ANOVA was performed for SBS, DC, SFE, and growth inhibition. Results The incorporation of AgNP solution decreased the SBS (p&lt;0.001) and DC in situ (p&lt;0.001) values. SFE decreased after addition of 0.18% and 0.33% AgNP. Growth inhibition of S. mutans in liquid media was obtained after silver addition (p&lt;0.05). Conclusions The addition of AgNP solutions to Transbond™ XT adhesive primer inhibited S. mutans growth. SBS, DC, and SFE values decreased after incorporation up to 0.33% AgNP solution without compromising the chemical and physical properties of the adhesive. <![CDATA[Occlusal changes secondary to temporomandibular joint conditions: a critical review and implications for clinical practice]]> ABSTRACT The relationship between Temporomandibular Disorders (TMD) and malocclusion is an extremely critical issue in dentistry. Contrary to the old concept that malocclusion causes TMD, occlusal changes, especially those observed as sudden, may be secondary and reflect joint or muscle disorders due to the obvious connection between these structures and the dental occlusion. Objectives The aim of this article is to present the most commonly occlusal changes secondary to TMD. Methods The clinical presentation of these conditions is discussed. Details regarding diagnosis, treatment, and follow-up of patients presenting TMD prior or during treatment are also presented. Conclusions All plans for irreversible therapy should be preceded by a meticulous analysis of TMD signs and symptoms in such a way that patients are not submitted to irreversible treatment, based on an untrue occlusal relationship, secondary to articular and/or muscular disorders. When present, TMD symptoms must always be controlled to reestablish a “normal” occlusion and allow proper treatment strategy.