Scielo RSS <![CDATA[Journal of Applied Oral Science]]> vol. 22 num. 3 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[Cell culture conditions: from outer space-like conditions to the mimicking of complex <em>in vivo</em> environments]]> <![CDATA[Current panorama of temporomandibular disorders' field in Brazil]]> In 2012, the recognition of the specialty of Temporomandibular Disorders and Orofacial Pain completed ten years. Given this scenario, it is extremely important to track the current situation of this field of knowledge in Brazil, specifically in the area of research and training. We hope to discuss the importance of the recognition of this specialty and the inclusion of these subjects in undergraduate programs in Dentistry. Objective: The objective of this study is to perform a bibliometric survey of researches regarding Temporomandibular Disorders and Orofacial Pain conducted in the country, determine the number of specialization courses in Orofacial Pain and the number of specialists in the field. Methods: The bibliometric survey was conducted based on the Dissertations Portal of Coordination for the Improvement of Higher education Personnel (CAPES) and on PubMed. The panorama of the field of Orofacial Pain and Temporomandibular disorders in Brazil was determined by searching on the website of the Brazilian Council of Dentistry. Results: We found 731 theses and dissertations with Temporomandibular Disorders and Orofacial Pain as the main subjects; 81 accredited/recognized Courses on Orofacial Pain and Temporomandibular Dysfunction completed; 8 accredited/recognized Specialization Courses on Orofacial Pain and Temporomandibular Dysfunction still in progress, and 1,064 registered specialists in Orofacial Pain and Temporomandibular Dysfunction in the Brazilian Council of Dentistry. Search in the PUBMED database yielded 576 articles published with the participation of Brazilian researchers as first authors and/or co-authors in the period from 2000 to 2013. From this amount, only 5 were published in Portuguese, while all the others were published in english. We can also notice that the number of published articles increases over time. Conclusion: The number of researches related to temporomandibular disorders has increased over the last ten years, as well as the number of specialization courses and the number of specialists, which represents a major breakthrough for this field of knowledge. <![CDATA[Influence of time, toothpaste and saliva in the retention of <em>Streptococcus mutans</em> and <em>Streptococcus sanguinis</em> on different toothbrushes]]> Objectives: The intraoral transmission of cariogenic and periodontopathogenic species seems to be facilitated by contaminated toothbrushes and other oral hygiene devices. The aim of this investigation was to analyze the in vitro retention and survival rate of Streptococcus mutans and Streptococcus sanguinis on different toothbrushes. The impacts of human saliva and antimicrobial toothpaste on these parameters were further evaluated. Material and Methods: Part I: Four toothbrushes (Colgate 360°, Curaprox CS5460 ultra soft, elmex InterX, Trisa Flexible Head3) were contaminated by S. mutans DSM 20523 or S. sanguinis DSM 20068 suspensions for three minutes. Bacteria were removed from the toothbrushes after either three minutes (T0) or 24 hours (T24) of dry storage and grown on Columbia blood agar plates for the quantification of colony-forming units (CFUs). Part II: The effects of saliva from a caries-active or a caries-inactive person and of toothpaste containing 0.12% chlorhexidine digluconate were also tested. Results: Part I: After three minutes of dry storage, approximately one percent of the bacteria were still detectable on the toothbrushes. After 24 hours, S. sanguinis exhibited a more pronounced decrease in viable cell numbers compared with S. mutans but the differences were not significant (Kruskal-Wallis test, p&gt;0.05). Part II: The addition of human saliva from a caries-active or caries-inactive person slightly increased the retention of both streptococcal species at T0. The use of toothpaste had no influence on the amount of viable streptococci at T0, but it reduced the microbial load after 24 hours of storage. There were only slight nonsignificant differences (p&gt;0.05) between the four toothbrushes. Conclusions: In vitro bacterial retention and survival of S. sanguinis and S. mutans on different toothbrushes occurred. Within the limitations of this study, the use of human saliva or an antimicrobial toothpaste did not lead to significant differences in the microbial load on toothbrushes. <![CDATA[Enamel crystals of mice susceptible or resistant to dental fluorosis: an AFM study]]> Objective: This study aimed to assess the overall apatite crystals profile in the enamel matrix of mice susceptible (A/J strain) or resistant (129P3/J strain) to dental fluorosis through analyses by atomic force microscopy (AFM). Material and Methods: Samples from the enamel matrix in the early stages of secretion and maturation were obtained from the incisors of mice from both strains. All detectable traces of matrix protein were removed from the samples by a sequential extraction procedure. The purified crystals (n=13 per strain) were analyzed qualitatively in the AFM. Surface roughness profile (Ra) was measured. Results: The mean (±SD) Ra of the crystals of A/J strain (0.58±0.15 nm) was lower than the one found for the 129P3/J strain (0.66±0.21 nm) but the difference did not reach statistical significance (t=1.187, p=0.247). Crystals of the 129P3/J strain (70.42±6.79 nm) were found to be significantly narrower (t=4.013, p=0.0013) than the same parameter measured for the A/J strain (90.42±15.86 nm). Conclusion: enamel crystals of the 129P3/J strain are narrower, which is indicative of slower crystal growth and could interfere in the occurrence of dental fluorosis. <![CDATA[Effect of root canal preparation, type of endodontic post and mechanical cycling on root fracture strength]]> Objective: To evaluate the impact of the type of root canal preparation, intraradicular post and mechanical cycling on the fracture strength of roots. Material and Methods: eighty human single rooted teeth were divided into 8 groups according to the instruments used for root canal preparation (manual or rotary instruments), the type of intraradicular post (fiber posts- FRC and cast post and core- CPC) and the use of mechanical cycling (MC) as follows: Manual and FRC; Manual, FRC and MC; Manual and CPC; Manual, CPC and MC; Rotary and FRC; Rotary, FRC and MC; Rotary and CPC; Rotary, CPC and MC. The filling was performed by lateral compactation. All root canals were prepared for a post with a 10 mm length, using the custom #2 bur of the glass fiber post system. For mechanical cycling, the protocol was applied as follows: an angle of incidence of 45°, 37°C, 88 N, 4 Hz, 2 million pulses. All groups were submitted to fracture strength test in a 45° device with 1 mm/ min cross-head speed until failure occurred. Results: The 3-way ANOVA showed that the root canal preparation strategy (p&lt;0.03) and post type (p&lt;0.0001) affected the fracture strength results, while mechanical cycling (p=0.29) did not. Conclusion: The root canal preparation strategy only influenced the root fracture strength when restoring with a fiber post and mechanical cycling, so it does not seem to be an important factor in this scenario. <![CDATA[A microleakage study of gutta-percha/AH Plus and Resilon/Real self-etch systems after different irrigation protocols]]> The development and maintenance of the sealing of the root canal system is the key to the success of root canal treatment. The resin-based adhesive material has the potential to reduce the microleakage of the root canal because of its adhesive properties and penetration into dentinal walls. Moreover, the irrigation protocols may have an influence on the adhesiveness of resin-based sealers to root dentin. Objective: The objective of the present study was to evaluate the effect of different irrigant protocols on coronal bacterial microleakage of gutta-percha/AH Plus and Resilon/Real Seal Self-etch systems. Material and Methods: One hundred ninety pre-molars were used. The teeth were divided into 18 experimental groups according to the irrigation protocols and filling materials used. The protocols used were: distilled water; sodium hypochlorite (NaOCl)+eDTA; NaOCl+H3PO4; NaOCl+eDTA+chlorhexidine (CHX); NaOCl+H3PO4+CHX; CHX+eDTA; CHX+ H3PO4; CHX+eDTA+CHX and CHX+H3PO4+CHX. Gutta-percha/AH Plus or Resilon/Real Seal Se were used as root-filling materials. The coronal microleakage was evaluated for 90 days against Enterococcus faecalis. Data were statistically analyzed using Kaplan-Meier survival test, Kruskal-Wallis and Mann-Whitney tests. Results: No significant difference was verified in the groups using chlorhexidine or sodium hypochlorite during the chemo-mechanical preparation followed by eDTA or phosphoric acid for smear layer removal. The same results were found for filling materials. However, the statistical analyses revealed that a final flush with 2% chlorhexidine reduced significantly the coronal microleakage. Conclusion: A final flush with 2% chlorhexidine after smear layer removal reduces coronal microleakage of teeth filled with gutta-percha/AH Plus or Resilon/Real Seal SE. <![CDATA[Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer]]> Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. Objective: The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. Material and Methods: The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10) in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%). Results: In relation to flowability: MTAF&gt;AH Plus&gt;MTAF5&gt;MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF&gt;AH Plus; for 7 and 14 days: MTAF5=MTAF10&gt;MTAF&gt;AH Plus. For the calcium release, for all periods: MTAF&gt;MTAF5=MTAF10&gt;AH Plus. Conclusions: The addition of 5% CH to the MTA Fillapex (in weight) is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential. <![CDATA[Modulation of cell proliferation, survival and gene expression by RAGE and TLR signaling in cells of the innate and adaptive immune response: role of p38 MAPK and NF-KB]]> Objective: The aim of this study was to evaluate a possible synergism between AGE-RAGE and TLR4 signaling and the role of p38 MAPK and NF-kB signaling pathways on the modulation of the expression of inflammatory cytokines and proliferation of cells from the innate and adaptive immune response. Material and Methods: T lymphocyte (JM) and monocyte (U937) cell lines were stimulated with LPS and AGE-BSA independently and associated, both in the presence and absence of p38 MAPK and NF-kB inhibitors. Proliferation was assessed by direct counting and viability was assessed by a biochemical assay of mitochondrial function. Cytokine gene expression for RAGe, CCL3, CCR5, IL-6 and TNF-α was studied by RT-PCR and RT-qPCR. Results: RAGE mRNA expression was detected in both cell lines. LPS and AGE-BSA did not influence cell proliferation and viability of either cell line up to 72 hours. LPS and LPS associated with AGE induced expression of IL-6 and TNF-α in monocytes and T cells, respectively. Conclusions: There is no synergistic effect between RAGE and TLR signaling on the expression of IL-6, TNF-α , RAGE, CCR5 and CCL3 by monocytes and lymphocytes. Activation of RAGE associated or not with TLR signaling also had no effect on cell proliferation and survival of these cell types. <![CDATA[Physical and chemical properties of orthodontic brackets after 12 and 24 months: <em>in situ</em> study]]> Objective: The aim of this article was to assess how intraoral biodegradation influenced the surface characteristics and friction levels of metallic brackets used during 12 and 24 months of orthodontic treatment and also to compare the static friction generated in these brackets with four different methods of the ligation of orthodontic wires. Material and Methods: Seventy premolar brackets as received from the manufacturer and 224 brackets that were used in previous orthodontic treatments were evaluated in this experiment. The surface morphology and the composition of the deposits found in the brackets were evaluated with rugosimetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Friction was analyzed by applying tensile tests simulating sliding mechanics with a 0.019x0.025" steel wire. The static friction levels produced by the following ligation methods were evaluated: loosely attached steel ligature around all four bracket wings, steel ligature attached to only two wings, conventional elastomeric ligation around all 4 bracket wings, and non-conventional Slide® elastomeric ligature. Results: The results demonstrated the presence of biodegradation effects such as corrosion pits, plastic deformation, cracks, and material deposits. The main chemical elements found on these deposits were Carbon and Oxygen. The maximum friction produced by each ligation method changed according to the time of intraoral use. The steel ligature loosely attached to all four bracket wings produced the lowest friction levels in the new brackets. The conventional elastic ligatures generated the highest friction levels. The metallic brackets underwent significant degradation during orthodontic treatment, showing an increase in surface roughness and the deposit of chemical elements on the surface. Conclusion: The levels of static friction decreased with use. The non-conventional elastic ligatures were the best alternative to reduce friction. <![CDATA[Assessment of quality of prescription by dental students]]> Objective: The main objective of this study was to evaluate changes in prescribing pattern of Dentistry students throughout academic course. Methods: A case of non-complicated dental extraction was presented to all students that had completed their pharmacology coursework (from 4th semester to the last semester). The students were grouped according to year of study and were asked to prescribe paracetamol for pain control. A maximal score of 5 points was calculated from three subscores for identification of professional and patient (1.0 point), drug concentration, dosage, and quantity (1.5 points); and drug information, instructions, and warnings (2.5 points). The data were expressed as medians [95% confidence intervals (CIs)] and were compared using the Kruskal-Wallis test followed by Dunn's post hoc test. A p&lt;0.05 value was considered statistically significant. A total of 92 students participated the study (2nd year, N=12; 3rd year, N=32; 4th year, N=28; 5th year, N=20). Results: The quality of prescription showed improvement between 2nd-year students [2.0 (1.5-2.5)] and 4th-year students [3.2 (2.9-3.5), p&lt;0.05]; 4th- and 5th-year students [3.6 (3.5-3.8)] performed similarly. Lack of information about pharmacological treatment, side effects, and administration route were the major deficiencies observed. Conclusion: Although Dentistry students present a general improvement in their prescribing performance, deficiencies remain even in advanced students. The data suggest that the teaching of good prescription practices should extend throughout the later phases of preprofessional dental education. <![CDATA[Effect of veneering material on the deformation suffered by implant-supported fixed prosthesis framework]]> Knowing how stresses are dissipated on the fixed implant-supported complex allows adequate treatment planning and better choice of the materials used for prosthesis fabrication. Objectives: The aim of this study was to evaluate the deformation suffered by cantilevered implant-supported fixed prostheses frameworks cast in silver-palladium alloy and coated with two occlusal veneering materials: acrylic resin or porcelain. Material and Methods: Two strain gauges were bonded to the inferior surface of the silver-palladium framework and two other were bonded to the occlusal surface of the prosthesis framework covered with ceramic and acrylic resin on each of its two halves. The framework was fixed to a metallic master model and a 35.2 N compression force was applied to the cantilever at 10, 15 and 20 mm from the most distal implant. The measurements of deformation by compression and tension were obtained. The statistical 2-way ANOVA test was used for individual analysis of the experiment variables and the Tukey test was used for the interrelation between all the variables (material and distance of force application). Results: The results showed that both variables had influence on the studied factors (deformation by compression and tension). Conclusion: The ceramic coating provided greater rigidity to the assembly and therefore less distortion compared with the uncoated framework and with the resin-coated framework. The cantilever arm length also influenced the prosthesis rigidity, causing higher deformation the farther the load was applied from the last implant. <![CDATA[Brazilian minipig as a large-animal model for basic research and stem cell-based tissue engineering. Characterization and <em>in vitro</em> differentiation of bone marrow-derived mesenchymal stem cells]]> Stem cell-based regenerative medicine is one of the most intensively researched medical issues. Pre-clinical studies in a large-animal model, especially in swine or miniature pigs, are highly relevant to human applications. Mesenchymal stem cells (MSCs) have been isolated and expanded from different sources. Objective: This study aimed at isolating and characterizing, for the first time, bone marrow-derived MSCs (BM-MSCs) from a Brazilian minipig (BR1). Also, this aimed to validate a new large-animal model for stem cell-based tissue engineering. Material and Methods: Bone marrow (BM) was aspirated from the posterior iliac crest of twelve adult male BR1 under general anesthesia. MSCs were selected by plastic-adherence as originally described by Friedenstein. Cell morphology, surface marker expression, and cellular differentiation were examined. The immunophenotypic profile was determined by flow cytometry. The differentiation potential was assessed by cytological staining and by RT-PCR. Results: MSCs were present in all minipig BM samples. These cells showed fibroblastic morphology and were positive for the surface markers CD90 (88.6%), CD29 (89.8%), CD44 (86.9%) and negative for CD34 (1.61%), CD45 (1.83%), CD14 (1.77%) and MHC-II (2.69%). MSCs were differentiated into adipocytes, osteoblasts, and chondroblasts as demonstrated by the presence of lipidic-rich vacuoles, the mineralized extracellular matrix, and the great presence of glycosaminoglycans, respectively. The higher gene expression of adipocyte fatty-acid binding protein (AP2), alkaline phosphatase (ALP) and collagen type 2 (COLII) also confirmed the trilineage differentiation (p&lt;0.001, p&lt;0.001, p=0.031; respectively). Conclusions: The isolation, cultivation, and differentiation of BM-MSCs from BR1 makes this animal eligible as a useful large-animal model for stem cell-based studies in Brazil. <![CDATA[Frictional resistance of self-ligating versus conventional brackets in different bracket-archwire-angle combinations]]> Objective: To compare the influence of archwire material (NiTi, beta-Ti and stainless steel) and brackets design (self-ligating and conventional) on the frictional force resistance. Material and Methods: Two types of brackets (self-ligating brackets - Smartclip, 3M/Unitek - and conventional brackets - Gemini, 3M/Unitek) with three (0, 5, and 10 degrees) slot angulation attached with elastomeric ligatures (TP Orthodontics) were tested. All brackets were tested with archwire 0.019"x0.025" nickel-titanium, beta-titanium, and stainless steel (Unitek/3M). The mechanical testing was performed with a universal testing machine eMIC DL 10000 (eMIC Co, Brazil). The wires were pulled from the bracket slots at a cross-head speed of 3 mm/min until 2 mm displacement. Results: Self-ligating brackets produced significantly lower friction values compared with those of conventional brackets. Frictional force resistance values were directly proportional to the increase in the bracket/ wire angulation. With regard to conventional brackets, stainless steel wires had the lowest friction force values, followed by nickel-titanium and beta-titanium ones. With regard to self-ligating brackets, the nickel-titanium wires had the lowest friction values, significantly lower than those of other materials. Conclusion: even at different angulations, the self-ligating brackets showed significantly lower friction force values than the conventional brackets. Combined with nickel-titanium wires, the self-ligating brackets exhibit much lower friction, possibly due to the contact between nickel-titanium clips and wires of the same material. <![CDATA[Caries-free subjects have high levels of urease and arginine deiminase activity]]> Objectives: This study investigated the relationship between urease and arginine deiminase system (ADS) activities and dental caries through a cross-sectional study. Material and Methods: Urease and ADS activities were measured in saliva and plaque samples from 10 caries-free subjects and 13 caries-active. Urease activity was obtained from the ammonia produced by incubation of plaque and saliva samples in urea. ADS activity was obtained from the ammonia generated by the arginine-HCl and Tris-maleate buffer. Specific activity was defined as micromoles of ammonia per minute per milligram of protein. Shapiro-Wilk statistical test was used to analyze the distribution of the data, and Mann-Whitney test was used to determine the significance of the data. Results: The specific urease activity in saliva and plaque was significantly higher in individuals with low DMFT scores. ADS activity in saliva (6.050 vs 1.350, p=0.0154) and plaque (8.830 vs 1.210, p=0.025) was also higher in individuals with low DMFT scores. Conclusions: Caries-free subjects had a higher ammonia generation activity by urease and arginine deiminase system for both saliva and plaque samples than low caries-active subjects. High levels of alkali production in oral environment were related to caries-free subjects. <![CDATA[Surgical techniques for the treatment of ankyloglossia in children: a case series]]> This paper reports a series of clinical cases of ankyloglossia in children, which were approached by different techniques: frenotomy and frenectomy with the use of one hemostat, two hemostats, a groove director or laser. Information on the indications, contraindications, advantages and disadvantages of the techniques was also presented. Children diagnosed with ankyloglossia were subjected to different surgical procedures. The choice of the techniques was based on the age of the patient, length of the frenulum and availability of the instruments and equipment. All the techniques presented are successful for the treatment of ankyloglossia and require a skilled professional. Laser may be considered a simple and safe alternative for children while reducing the amount of local anesthetics needed, the bleeding and the chances of infection, swelling and discomfort.