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UNLABELLED: The aims of the present study were to evaluate the association between breastfeeding and breathing development and to investigate associations between breastfeeding duration and the breathing patterns in children. A cross-sectional study was carried out at the Institute of Integrative Medicine Professor Fernando Figueira, Recife, Brazil, with a random sample of 732 children aged between 6 and 9 years. Breastfeeding and breathing patterns were identified using a questionnaire that was filled out by mothers or guardians, and a clinical examination of the children. Data were analyzed statistically by Pearson's chi-square test at 5 % significance level. The prevalence of mouth breathing was 48 %, whereas 52 % of the children were nasal breathers. Six hundred-forty children were breastfed; 46.2 % of them were mouth breathers and 53.8 % were nasal breathers. Ninety-two children were not breastfed; 59.8 % of them were mouth breathers and 40.2 % were nasal breathers. Breastfeeding for 24 months or more, as well as exclusive breastfeeding in the first 6 months, was associated with the development of nasal breathing. CONCLUSIONS: Extended breastfeeding was associated with correct development of the breathing pattern.
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Lactancia Materna , Respiración por la Boca/epidemiología , Respiración , Brasil , Niño , Estudios Transversales , Femenino , Humanos , Masculino , Prevalencia , Encuestas y CuestionariosRESUMEN
Horizontal root fractures usually are characterized by a fracture line that is perpendicular to the long axis of the tooth's root. Root fractures are diagnosed through clinical and radiographic examination. Treatment depends on the position of the fracture and the extent of root involvement. Successful treatment depends on correct diagnosis, clinical management, and radiographic follow-up. This article describes the successful treatment (with a 3-year follow-up period) of a permanent maxillary central incisor with horizontal root fracture treated with calcium hydroxide, in which the coronal segment was necrotic and the apical segment remained vital.
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Tratamiento del Conducto Radicular/métodos , Fracturas de los Dientes/terapia , Raíz del Diente/lesiones , Adulto , Humanos , Incisivo , Masculino , MaxilarRESUMEN
Noma (also known as cancrum oris) is classified by the World Health Organization as a necrotizing ulcerative stomatitis, an invasive acute infection which affects the orofacial tissues. Patients who are subject to such risk factors as severe malnutrition or alteration of the immune system are predominantly affected. This article presents a case of noma in a 62-year-old immunocompromised patient with pain and tooth mobility in the mandibular region, ulceration, bleeding, gingival inflammatory secretion, and oral malodor. The signs and symptoms were controlled only after the intravenous administration of 500 mg tid of imipenem/cilastatin sodium and 2 g qd of vancomycin. After infection control was maintained, the patient was directed to surgery for removal of bone sequestration and curettage of the maxillary sinus. The patient was prescribed 1 g qd of oral clindamycin for 3 months postsurgery.
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Huésped Inmunocomprometido , Noma/diagnóstico , Femenino , Humanos , Persona de Mediana Edad , Noma/inmunologíaRESUMEN
BACKGROUND: In dentistry, clinical practice is directed towards attitudes that promote oral health and the paediatricians occupy a privileged position in this process. AIM: To assess the knowledge and attitudes of paediatricians in relation to the oral health of their patients. DESIGN: A cross-sectional study was carried out at the Institute of Integrative Medicine Professor Fernando Figueira, Recife, Brazil. A total of 182 paediatricians participated by filling out a questionnaire. RESULTS: A total of 63.9% believed the first visit to the dentist should occur before the child completes 1 year of life. Moreover, 67.8% considered their knowledge on oral health to be insufficient. Approximately 78% of the paediatricians diagnosed caries through an analysis of cavities. Only 29.9% always recommended fluoride dentifrice. The term 'fluorosis' was unknown by 48.3% of the respondents. Concerning pacifiers, 32.6% did not allow it and 66.9% did not either recommend it or restrict it. A total of 83.4% classified the oral health content in their medical education as either nonexistent or deficient; this figure remained high (72.4%) in relation to residency. CONCLUSIONS: It is important to develop oral health information programmes to paediatricians. Information on oral health should be included in medical curricula and residency.
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Actitud del Personal de Salud , Educación Médica , Salud Bucal , Pediatría/educación , Médicos/psicología , Adulto , Anciano , Brasil , Cariostáticos/uso terapéutico , Competencia Clínica , Estudios Transversales , Curriculum , Atención Dental para Niños , Caries Dental/diagnóstico , Dentífricos/uso terapéutico , Femenino , Fluoruros/uso terapéutico , Fluorosis Dental/diagnóstico , Educación en Salud Dental , Conocimientos, Actitudes y Práctica en Salud , Humanos , Lactante , Masculino , Persona de Mediana Edad , Chupetes , Derivación y Consulta , Adulto JovenRESUMEN
BACKGROUND: This study compared the quality of marginal sealing in the gingival wall of class II preparations of two low-shirinkage resins of the bulk fill type with a conventional resin isolated or associated with a glass ionomer cement (GIC). MATERIAL AND METHODS: 40 human molars were divided into 4 groups and 80 occlusal-mesial and occlusal-distal restorations were performed with the following materials: SureFil SDR flow, Filtek Bulk Fill Posterior, Z250 resins and Riva Light Cure GIC. 40 restorations were evaluated in Scanning Electron Microscopy (SEM) with Elemental Microanalysis Spectrometry (EDS) initially and the remainder after a period of 6 months of aging in a 37 ± 5°C oven. An average of the silver penetration at each restoration was obtained in the two evaluations and the results were statistically analyzed in a descriptive and inferential way, through the paired t-Student and one-way ANOVA F-test. RESULTS: There were no significant statistical differences between the materials with respect to silver nanoinfiltration, except for the Bulk Fill Posterior/3M ESPE resin compared to the GIC and conventional resin in the final evaluation. CONCLUSIONS: The low shrinkage resins showed a similar behavior in relation to the marginal sealing quality observed in the GIC or composite resin with the incremental technique, also presenting the advantage of simplicity in the technique of confection of the restorations and reduction of the time of work. Key words:Resin composites, Bulk fill, dental restorations, marginal quality, adhesion.
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Different HERO rotary systems were evaluated by pre- and postoperative images of a cross-section of their mesiobuccal root thirds with a stereoscopic magnifier (45x). Fifty mesiobuccal canals of human mandibular first molars were divided into five groups: 1--HERO 642; 2--HERO 642 and HERO Apical; 3--HERO Shaper; 4--HERO Shaper and HERO Apical; 5--NitiFlex files. The perimeter of the canal was calculated using Image Tool software (UTHSCA). Final, post-instrumentation perimeters were compared by Kruskal-Wallis test (P = 0.05). The distribution of the values of the final canal perimeter for each instrumentation method was not statistically significant in any of the thirds (P = 0.174, cervical third; P = 0.874, middle third; and P = 0.631, apical third). An increase in canal perimeter was observed in all groups. In the cervical third the greatest increase was Group 5; in the middle third, Group 4, and in the apical third, Group 2.
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Instrumentos Dentales , Preparación del Conducto Radicular/instrumentación , Aleaciones Dentales , Análisis del Estrés Dental , Dentina , Humanos , Diente Molar , Níquel , TitanioRESUMEN
Introduction: Photodynamic therapy (PDT) has emerged as a powerful tool for conventional endodontic treatment, capable of eradicating microorganisms present in endodontic infections. Despite this, the use of PDT in the surgical endodontic treatment is not well-known. Case Report: This paper describes the case of a patient with asymptomatic apical periodontitis in a mandibular incisor submitted to surgical endodontic treatment associated with PDT. After conventional procedures, photosensitizer methylene blue (0.01%) was applied to the retrograde cavity for 3 minutes, followed by irradiation with diode laser (100 mW and 660 nm) for 3 minutes. Six months after the procedure, the patient was asymptomatic, and the radiographic examination showed healthy periradicular tissues. Conclusion: The association of PDT with surgical endodontic treatment was effective, suggesting that this therapy may provide additional benefits to patients when compared to the conventional surgical technique.
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The aim of the present study was to assess the risk of deviation of the root canals prepared by 3 HERO rotary systems, used solely or in association, by means of preoperative and postoperative imaging of a cross-section of their coronal, middle, and apical thirds. Fifty mesiobuccal canals of human first molars were randomly divided into 5 groups of 10 specimens each: group A, HERO 642; group B, HERO 642 + HERO Apical; group C, HERO Shaper; group D, HERO Shaper + HERO Apical; group E (control), NitiFlex files. Fisher exact test showed that the differences between the percentages of the presence of deviation and the differences observed between the proportions of instrumented and noninstrumented walls were not statistically significant. No system presented absolute effectiveness, because each of them produced morphologic changes and failed to instrument all the walls of the root canals. A level of significance of .05 was adopted.
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Instrumentos Dentales/efectos adversos , Cavidad Pulpar/patología , Preparación del Conducto Radicular/instrumentación , Diseño de Equipo , Humanos , Diente Molar , Preparación del Conducto Radicular/efectos adversosRESUMEN
OBJECTIVE: The aim of the present study was to determine the prevalence of asymptomatic apical periodontitis (AAP) and its association with coronary artery disease (CAD) in a Brazilian subpopulation, and to examine the correlation of AAP with gender, age and most frequently affected dental elements. METHODS: The data were collected from medical records of the patients (n = 1346) treated at the Specialization in Endodontics Clinic of the Federal University of Pernambuco in the period between 2003 and 2010. From each patient, the following variables were recorded: gender, age, endodontically compromised teeth, endodontic diseases diagnosed and the history of CAD. The data were analyzed using Pearson's chi-square test adopting a significance level of 5%. RESULTS: AAP was diagnosed in 574 patients (42.6%), corresponding to 641 teeth (40.1%). Both genders (p = 0.082), and all age groups (p = 0.190) were affected similarly. The upper incisors (52.8%, p <0.001) had a higher prevalence of AAP. The patients with AAP showed 1.45 times more chance of exhibiting CAD (p = 0.307). CONCLUSIONS: The results pointed out that the prevalence of AAP in this population was high and similar to that observed in other countries. A positive association, but not statistically significant, between AAP and CAD was found.
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INTRODUCTION: This study aimed to compare apical microcrack formation after root canal shaping by hand, rotary, and reciprocating files at different working lengths using micro-computed tomographic analysis. METHODS: Sixty mandibular incisors were randomly divided into 6 experimental groups (n = 10) according to the systems and working lengths used for the root canal preparation: ProTaper Universal for Hand Use (Dentsply Maillefer, Ballaigues, Switzerland), HyFlex CM (Coltene-Whaledent, Allstetten, Switzerland), and Reciproc (VDW, Munich, Germany) files working at the apical foramen (AF) and 1 mm short of the AF (AF - 1 mm). The teeth were imaged with micro-computed tomographic scanning at an isotropic resolution of 14 µm before and after root canal preparation, and the cross-sectional images generated were assessed to detect microcracks in the apical portion of the roots. RESULTS: Overall, 17 (28.3%) specimens presented microcracks before instrumentation. Apical microcracks were present in 1 (ProTaper Universal for Hand Use), 3 (Hyflex CM), and 2 (Reciproc) specimens when the instrumentation terminated at the AF. When instrumentation was terminated at AF - 1 mm, apical microcracks were detected in 3 (ProTaper Universal for Hand Use) and 4 (Hyflex CM and Reciproc) specimens. All these microcracks detected after root canal preparation were already present before instrumentation, and no new apical microcrack was visualized. For all groups, the number of slices presenting microcracks after root canal preparation was the same as before canal preparation. CONCLUSIONS: Root canal shaping with ProTaper Universal for Hand Use, HyFlex CM, and Reciproc systems, regardless of the working length, did not produce apical microcracks.
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Preparación del Conducto Radicular/efectos adversos , Ápice del Diente/lesiones , Fracturas de los Dientes/etiología , Humanos , Preparación del Conducto Radicular/instrumentación , Ápice del Diente/diagnóstico por imagen , Fracturas de los Dientes/diagnóstico por imagen , Microtomografía por Rayos XRESUMEN
INTRODUCTION: This study aimed to evaluate the ability of 2 optical coherence tomographic (OCT) systems to detect apical dentinal microcracks. METHODS: Twenty extracted human single-rooted mandibular incisors were selected. After root canal preparation with an R40 Reciproc file (VDW, Munich, Germany), the specimens presenting apical microcracks were identified using micro-computed tomographic (micro-CT) scanning as the gold standard. Then, the apical portions of the roots were imaged with spectral domain OCT (SD-OCT) and swept-source OCT systems, and the resulting images were blindly evaluated by 3 independent examiners to detect microcracks. The diagnostic performance of each OCT device was calculated, and statistical analysis was performed. RESULTS: Based on the micro-CT images, 12 (60%) roots presented dentinal microcracks in the apical region. The images generated by the OCT systems were able to show microcrack lines at the same location as the corresponding micro-CT cross sections. Although the diagnostic performance of the SD-OCT device was superior, there were no statistically significant differences between the 2 OCT devices (P > .05). Interexaminer agreement was substantial to almost perfect for the SD-OCT system and moderate to almost perfect for the swept-source OCT system, whereas intraexaminer agreement was substantial to almost perfect for both OCT devices. CONCLUSIONS: The detection ability verified for both OCT systems renders them promising tools for the diagnosis of apical microcracks.
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Radiografía Dental/métodos , Tomografía de Coherencia Óptica/métodos , Ápice del Diente/lesiones , Fracturas de los Dientes/diagnóstico por imagen , Humanos , Ápice del Diente/diagnóstico por imagenRESUMEN
The objective of this study was to evaluate the effect of root canal preparation with single-file reciprocating systems at different working lengths on the development of apical microcracks using micro-computed tomographic (micro-CT) imaging. Forty extracted human mandibular incisors were randomly assigned to 4 groups (n=10) according to the systems and working length used to prepare the root canals: Group A - WaveOne Gold at apical foramen (AF), Group B - WaveOne Gold 1 mm short of the AF (AF-1 mm), Group C - Unicone (AF) and Group D - Unicone (AF-1 mm). Micro-CT scanning was performed before and after root canal preparation at an isotropic resolution of 14 µm. Then, three examiners assessed the cross-sectional images generated to detect microcracks in the apical portion of the roots. Apical microcracks were visualized in 3, 1, 1, and 3 specimens in groups A, B, C, and D, respectively. All these microcracks observed after root canal preparation already existed prior to instrumentation, and no new apical microcrack was detected. For all groups, the number of slices presenting microcracks after root canal preparation was the same as before canal preparation. Root canal preparation with WaveOne Gold and Unicone, regardless of the working length, was not associated with apical microcrack formation.
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Ápice del Diente/diagnóstico por imagen , Fracturas de los Dientes/diagnóstico por imagen , Microtomografía por Rayos X/métodos , Humanos , Ápice del Diente/lesionesRESUMEN
OBJECTIVE: Apical deviations are important factors in endodontic therapy, since they can cause the treatment failure. The aim of the present study was to determine the centering capacity of ProTaper Universal™, Twisted File™ and Revo-S® rotary systems using cone beam computed tomography analysis before and after the instrumentation of root canals. MATERIALS AND METHODS: Thirty mesiobuccal roots from human lower first molars were divided into three groups of ten: Group 1 - ProTaper Universal™ Rotary System; Group 2 - Twisted File™ Rotary System; and Group 3 - Revo-S® Rotary System. All teeth were scanned using computed tomography to determine the condition of the root canal before and after instrumentation (4mm, 3mm and 2mm from the root apex). Images were made using ICAT VISION software for both instrumented and non-instrumented canals. RESULTS: The results were analyzed statistically using the Kolmogorov-Smirnov normality test for quantitative variables. Comparisons were made with two groups (Mann-Whitney - abnormal) and with more than two groups (Kruskal Wallis - abnormal). The level of significance was set at p<0.05. A statistically significant difference was found for the measurement of 4 mm between the "ProTaper Universal" and "Twisted File" systems. For the Twisted File system, a statistically significant difference was recorded between the measurements of 4mm and 3 mm. CONCLUSION: None of the assessed instruments was completely effective in terms of the biomechanical preparation of root canals since all created deviation from the original anatomy of the canal.
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PURPOSE: Solvents may be used to remove the filling materials. The purpose of this in vitro study was to evaluate and compare the efficacy of formulated orange oil, orange oil and formulated eucalyptol in dissolving F3 ProTaper Universal Gutta-percha points. MATERIAL AND METHODS: 200 samples were used and divided into four groups, further divided in fifty samples for each solvent. The samples were weighed on an analytical balance before being subjected to the action of solvents. Subsequently, they were put onto watch glasses, 7X45mm in length, and immersed into solutions for the following times: 5, 10, 20, 25 and 30 minutes. The loss of mass was recorded by weighing samples after every minute of action of the solvent on the points. Data were statistically analyzed by Kruskal-Wallis test at a significance level of 5%. RESULTS: All solvents showed that the first five minutes of action was the period of greatest dissolving power. In terms of immersion time, xylol (control group) exhibited a markedly superior ability in dissolving the gutta-percha points compared to other solvents and, also, showed statistically significant differences. A continuous dissolution was observed in all groups. Formulated orange oil presented a markedly superior solvent effect on filling materials compared to orange oil and formulated eucalyptol; however, there were no statistically significant differences. CONCLUSION: Considering the results obtained and methodology employed, it can be concluded that xylol was the most effective solvent in dissolving gutta-percha points, followed by formulated orange oil, orange oil and formulated eucalyptol oil.
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OBJECTIVE: The aim of this study was to present an atypical case of a C-shaped root canal that was present in the vestibular root of a permanent maxillary second molar using PreXion 3-D cone-beam computed tomography (CBCT) as a diagnostic device. MATERIALS AND METHODS: A 50-year-old female patient was referred for routine examination to a private diagnostic imaging clinic in Recife-Pernambuco. During the physical examination, the presence of an unusual C-shaped anatomy in the vestibular canal with a mesiodistal interconnection that extended from the apical to the cervical third was detected in axial slices acquired with a PreXion 3-D scanner. RESULTS: Although C-shaped root canals are most frequently observed in the mandibular second molar, this case presented a rare finding in the permanent maxillary second molar. CONCLUSIONS: PreXion 3-D CBCT has emerged as a new high-resolution imaging test technology, thus assisting with the diagnosis of anatomical variations such as C-shaped root canals. However, such imaging technology is not recommended for routine use.
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INTRODUCTION: The aim of this study was to compare the efficacy of the Nd:YAG laser, ultrasound, the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland), and the CanalBrush (Coltene Whaledent, Langenau, Germany) methods for the removal of the smear layer from the apical third of root canals. METHODS: Fifty distal root canals from extracted human mandibular first molars were instrumented up to ProTaper Universal F5 and divided randomly into 5 groups (n = 10) according to the following final irrigation agitation techniques: no agitation (control), ProTaper Universal file, ultrasound, CanalBrush, and Nd:YAG laser. Specimens were observed under a scanning electron microscope. The presence of the smear layer was evaluated using a 3-grade scoring system. The data were analyzed with Cohen kappa, Kruskal-Wallis, and Mann-Whitney U tests. A level of significance of .05 was adopted. RESULTS: The ultrasound group performed significantly better than the rest of the groups; 56.6% of the specimens revealed no smear layer, 44.4% showed the presence of a moderate smear layer, and no heavy smear layers were observed. In the Nd:YAG laser group, 30% of the specimens presented with no smear layer, 70% showed the presence of a moderate smear layer, and no heavy smear layers were observed. In contrast, a heavy smear layer was observed on the surfaces of the root canals in the CanalBrush (23.4%), ProTaper Universal (13.4%), and control (86.6%) groups. Statistically significant differences were observed (P < .05). CONCLUSIONS: None of the agitation methods completely removed the smear layer. However, the ultrasound method performed significantly better followed by the Nd:YAG laser, the CanalBrush, and the ProTaper Universal system. Agitation of the irrigant improved smear layer removal in the apical third of the canal.
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Láseres de Estado Sólido , Preparación del Conducto Radicular/métodos , Capa de Barro Dentinario/diagnóstico por imagen , Cepillado Dental , Ultrasonido , Adolescente , Humanos , Capa de Barro Dentinario/patología , Diente/diagnóstico por imagen , Diente/ultraestructuraRESUMEN
AIM: The aim of this in vitro study was to evaluate the efficacy of photodynamic therapy (PDT) and sodium hypochlorite (NaOCl) in root canal disinfection by a single-file instrumentation technique. MATERIAL AND METHODS: Seventy human single-rooted mandibular premolars were infected with Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, and divided into seven groups (n=10) according to the protocol of disinfection used. Group 1: 1% NaOCl; Group 2: 5.25% NaOCl; Group 3: saline+PDT; Group 4: 1% NaOCl+PDT; Group 5: 5.25% NaOCl+PDT; Group 6: positive control; Group 7: negative control. For PDT, methylene blue (15µg/mL) remained in the root canal for 2min, followed by irradiation with diode laser. Samples were collected before and after instrumentation and plated in specific media cultures, to assess the presence or absence of microbial growth and determine the average reduction of viable microorganisms. RESULTS: 5.25% NaOCl+PDT resulted in the highest number of specimens with no microbial growth. Also, 1% NaOCl and 1% NaOCl+PDT exhibited similar antimicrobial effects. Saline+PDT was not able to eliminate all microorganisms. There was statistical significant differences between the groups and the microorganisms. CONCLUSION: The association of 5.25% NaOCl with PDT was the most effective treatment against microorganisms from endodontic infection in root canals instrumented by a single-file instrumentation technique. This result shows that PDT can be useful to improve the root canal disinfection.
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Cavidad Pulpar/efectos de los fármacos , Cavidad Pulpar/microbiología , Azul de Metileno/uso terapéutico , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes/uso terapéutico , Hipoclorito de Sodio/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Candidiasis/tratamiento farmacológico , Relación Dosis-Respuesta a Droga , Humanos , Viabilidad Microbiana , Técnicas Microbiológicas , Hipoclorito de Sodio/administración & dosificaciónRESUMEN
OBJECTIVE: This in vitro study aimed to evaluate the efficacy of the disinfection of root canal systems carried out with Reciproc(TM) and ProTaper Universal(TM) systems using 1% sodium hypochlorite (NaOCl). METHODS: Forty human single-rooted mandibular premolars were infected with Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, and twenty were not infected. The specimens were randomly divided into 6 groups (n = 10): Group 1: ProTaper Universal(TM) + 1% NaOCl; Group 2 (positive control): ProTaper Universal(TM) + saline; Group 3 (negative control without microorganisms): ProTaper Universal(TM) + saline; Group 4: Reciproc(TM) + 1% NaOCl; Group 5 (positive control): Reciproc(TM) + saline; Group 6 (negative control without microorganisms): Reciproc(TM) + saline. Samples were collected before and after the completion of specific treatments, and plated in specific media cultures. The Fisher exact test was used for the statistical analysis of differences in terms of presence or absence of microbial growth among groups. For all tested pathogens, significant differences (p < 0.001) were verified between the instrumentation systems used. RESULTS: ProTaper Universal(TM) associated with 1% NaOCl completely eliminated all microorganisms. Microbial growth, however, was observed when Reciproc(TM) was used associated with 1% NaOCl. CONCLUSION: According to the protocol executed for this study, the Reciproc(TM) system associated with 1% NaOCl was not able to completely eliminate E. faecalis, P. aeruginosa, S. aureus and C. albicans from the root canal systems.
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Photodynamic therapy (PDT) is presented as a promising antimicrobial therapy that can eliminate microorganisms present in endodontic infections. This treatment is based on the use of a nontoxic photosensitizing agent followed by irradiation of a resonant light source being capable of generating highly reactive species that are harmful to microorganisms. The purpose of this paper is to review the dental literature about the main factors that encompass the use of PDT combined with endodontic treatment for decontamination of the root canal system. A literature search was performed using the following index databases: PubMed, ISI Web of Knowledge and MedLine, between 2000 and 2014, looking for studies regarding antimicrobial action of PDT and its application to endodontic therapy. It was observed that despite numerous promising results, it is still necessary to establish different parameters so that PDT can be used with maximum effectiveness in eliminating microorganisms that cause endodontic infections.
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PURPOSE: The purpose of this study was to evaluate the association between breast-feeding duration and the subsequent occurrence of posterior crossbite in Brazilian children. METHODS: A cross-sectional study was conducted involving 714 six- to nine-year-old children. A questionnaire was completed by mothers or guardians of the children concerning the length of time they were exclusively breast-fed and the breast-feeding duration. A clinical examination of each child was conducted to detect posterior crossbite. Data were analyzed using Pearson's chi-square test at a five percent significance level. RESULTS: There was a posterior crossbite prevalence of approximately 15 percent. There was no statistically significant association between posterior crossbite and age or gender ( P >.05). The prevalence of posterior crossbite was higher among children who were not breast-fed (28 percent) than among breast-fed children (13 percent). There was a significant association between posterior crossbite and the length of time that children were exclusively breast-fed and the breast-feeding duration ( P <.05 percent). CONCLUSION: The prevalence of posterior crossbite gradually decreased as exclusive breast-feeding duration increased, and there was a relationship between breast-feeding duration and the occurrence of posterior crossbite.