Search

Aim: To determine the frequency of signs and/or symptoms compatible with COVID-19 in Paraguayan dentists, as well as the possible source of contagion. Material and Methods: Online survey consisting of 13 questions, applied to all dentists in Paraguay from January 20 to February 15, 2021. Results: A total of 433 dentists participated in the survey; 47.5% displayed symptoms compatible with COVID-19 and 13.39% indicated that they had contracted the disease, providing confirmation via a positive test result. Headache, loss of smell, loss of taste, cough, and fatigue were the most prevalent symptoms among COVID-19 positive cases. The main source of contagion was the family nucleus. Only one participant reported having contracted the disease while providing dental care. Conclusion: Almost half of the dentists displayed symptoms compatible with COVID-19. Only 13.39% tested positive for COVID-19. Only one case of contagion was reported to have happened during the provision of dental care.

Introducción: en diciembre del 2019, se reporta en el mundo un caso de neumonía causada por el coronavirus 2 (SARS-CoV-2). En Paraguay, actualmente se registraron más de 428.000 casos confirmados y más de 13.500 muertes. En ese contexto, la enseñanza ha tenido que convocarse al entorno virtual generando, en todos los niveles, modificaciones reactivas conductuales nacidas desde diversas causas: la dificultad al acceso a elementos informáticos, necesidad en diversos grados de reaprendizaje en un entorno no habitual y sobre todo la incertidumbre. El objetivo del estudio fue determinar los niveles de depresión, ansiedad y estrés durante la pandemia covid-19 en estudiantes de Odontología. Métodos: para este estudio observacional descriptivo de corte transversal se incluyeron estudiantes de grado de la Facultad de Odontología de la Universidad Nacional de Asunción, matriculados al periodo académico 2021. Se utilizó la escala de Depression, Anxiety and Stress (DASS-21) short form. Cada uno de los tres ejes (depresión, ansiedad y estrés) contiene 7 ítems, divididas en subescalas de contenido similar. Las puntuaciones fueron categorizadas en cinco grupos ordenados (normal, leve, moderada, severa y muy severa). Resultados: los estudiantes de Odontología presentaron cuadros de depresión y ansiedad, con síntomas de ansiedad moderada en un 42,58%; 1,29% presentó depresión severa. Conclusión: la mayoría de los estudiantes de Odontología presentaron cuadros de depresión y ansiedad con síntomas muy comunes, como la imposibilidad de relajarse, falta de iniciativa, irritabilidad y nervios.

AIM To evaluate the impact of the presence and treatment of periodontal disease (PD) and apical periodontitis (AP) on the aorta and liver of obese and non-obese rats. METHODOLOGY One hundred and forty Wistar rats were divided into two groups, according to the diet administered: normal diet (-n), without obesity; and cafeteria diet (-c), with induced obesity. These groups were divided into seven subgroups according to the specific experimental protocols: naive control (NC); AP; AP with treatment (APt); PD; PE with treatment (PDt); AP and PD (APPD); and AP and PD with treatment (APPDt). AP and PD lesions were induced for four weeks. Four weeks after treatments, the animals were euthanatized, and the aorta and liver were dissected for histological evaluation. For the comparison of the thickness of the aorta between groups, the Kruskal-Wallis test was used, followed by the Mann-Whitney test. For the analysis of other variables related to the aorta and liver outcomes, logistic regression was carried out. RESULTS Both PD and AP were associated with the development of histological alterations in the aortic arch, with no significant difference between obese and non-obese animals (p = .17). The aorta thickness was increased significantly (p

To determine the influence of periapical lesions on the repeatability of two electronic apex locators (EALs), Root ZX II, and RomiApex A-15, in maxillary anterior teeth, in vivo. After approval by the local ethics committee, 43 maxillary anterior teeth scheduled for root canal therapy were assigned to two groups. The periapical lesion (PAL) group included 21 teeth with necrotic pulps and radiographically visible periapical lesion, and the normal periapex (NPA) group consisted of 22 teeth with vital pulps and no periapical lesion. In each canal, Root ZX II and RomiApex A-15 were used to determine working length defined as the “zero” reading on the display. Two consecutive measurements were performed with each EAL on each tooth and a second operator measured the endodontic file with a digital caliper without knowledge of the EAL being used or the tooth diagnosis. The absolute value of the difference between the first and second measurement (measurement pairs) was calculated. Repeatability was evaluated by the Bland-Altman method, and an aligned ranks transformation ANOVA was conducted to compare the EALs. The median absolute difference between measurement pairs was significantly lower (p < 0.001) and the limits of agreement were narrower in the NPA group. Among the EALs, median absolute differences were significantly smaller for Root ZX (p < 0.001). Measurements were more repeatable when no periapical lesion was present. Root ZX showed better repeatability than RomiApex. Periapical lesions seem to influence successive in vivo measurements with EALs.

To assess the effect of additional apical enlargement using nickel titanium (NiTi) instruments on the incidence of microcracks using micro-computed tomographic analysis. Fifty-one premolars with single canals were enlarged to ProTaper Gold (PTG) F2 (25/08) (Dentsply Sirona), ProFile Vortex Blue (VB) 25/06 (Dentsply Tulsa), or WaveOne Gold (WOG) primary (25/07) (Dentsply Sirona) NiTi rotary instruments (n = 17 each). Afterward, additional apical enlargement was performed in each group with its corresponding larger instrument (F3 (30/09), VB 30/06, or WOG Medium (35/06) instruments, respectively). All teeth were imaged with micro-computed tomography before canal enlargement and after initial and additional apical enlargements to detect new microcracks at the apical 5 mm. An Aligned Rank Transform ANOVA was conducted to examine the effects of file type and canal enlargement on the number of new microcracks resulting from enlargement. A Kruskal-Wallis test was run to compare the file types at each canal enlargement stage. A significant main effect (P = 0.026) of canal enlargement on the number of new microcracks was found; the number of apical microcracks found after additional enlargement was significantly greater than baseline (P = 0.021); no significant difference was found between baseline and initial enlargement (P = 0.506) and between initial enlargement and additional enlargement (P = 0.252). The Kruskal-Wallis tests found no difference between file types at baseline (P = 0.348), after initial enlargement (P = 0.369) or additional enlargement (P = 0.133). Regardless of the instrumentation system used, additional apical enlargement led to the formation of high number of new microcracks. The results indicated that additional enlargement induced significant number of apical microcracks.

El uso descontrolado de los antibioticos favorecio el desarrollo de resistencia bacteriana que va aumentando considerablemente conforme van pasando los anos y se ha convertido en una de las mayores amenazas para la salud publica. Es por ello que el Ministerio de Salud Publica y Bienestar Social (MSPyBS) emitio la Resolucion S.G. N° 576/18 en la que se dispone la venta obligatoria de medicamentos que tengan actividad antibiotica de uso sistemico bajo receta simple archivada. El objetivo de este trabajo fue medir el nivel de conocimiento y practica de la normativa de la receta simple archivada para la prescripcion de antibioticos de uso sistemico en odontologos de Asuncion y Gran Asuncion. El diseno del estudio fue observacional descriptivo, de corte transversal, en donde participaron 190 profesionales odontologos. Los resultados obtenidos en este estudio mostraron que el 77,89% de los odontologos respondio que conoce la Resolucion S.G. N° 576/18 del MSPyBS, y 94,21% respondio que sabe que datos incluir en la receta simple archivada. Solo 11,28% incluye correctamente todos los datos requeridos. Tambien se pudo observar que la amoxicilina es el antibiotico mas recetado por los odontologos (79,47%). En conclusion, se observo que solo el 40,0% de los profesionales encuestados tuvieron un nivel de conocimiento suficiente, mientras que el 60,52% tuvo un nivel de practica adecuado.

RESUMEN: El objetivo de este estudio fue comparar la estructura dentaria removida utilizando dos técnicas de acceso endodóntico diferentes en incisivos mandibulares. Treinta y cinco incisivos mandibulares extraídos fueron pesados individualmente con una balanza de precisión. Después de las radiografías iniciales tomadas por vestibular y proximal, los dientes fueron codificados y asignados aleatoriamente a dos grupos: acceso convencional (n = 17) o acceso incisal (n = 18). Luego se volvieron a pesar los dientes y se repitieron las radiografías. Las radiografías digitales se cargaron a un editor de imágenes (Adobe Photoshop) para la sustracción digital de las imágenes por las incidencias VP y MD. Dos observadores independientes y calibrados realizaron las mediciones de las áreas sustraídas. La concordancia inter-observador fue casi perfecta; coeficiente de correlación intraclase igual a 0,94 y 0,98 para las incidencias MD y VP, respectivamente. La prueba de Mann-Whitney encontró diferencias estadísticamente significativas entre los tipos de acc esos en cuanto a la diferencia mediana de los pesos (p = 0,0073) y el área VL (p = 0.0023). También encontró una diferencia estadísticamente significativa entre los tipos de acceso en cuanto al área MD (Prueba t de Welch, p < 0,001). La diferencia de peso fue menor para el acceso incisal que para el acceso convencional. El acceso incisal removió menos tejido dentario que el acceso convencional.

Panoramic dental radiography is one of the most used images of the different dental specialties. This radiography provides information about the anatomical structures of the teeth. The correct evaluation of these radiographs is associated with a good quality of the image obtained. In this study, 598 patients were consecutively selected to undergo dental panoramic radiography at the Department of Radiology of the Faculty of Dentistry, Universidad Nacional de Asunción. Contrast enhancement techniques are used to enhance the visual quality of panoramic dental radiographs. Specifically, this article presents a new algorithm for contrast, detail and edge enhancement of panoramic dental radiographs. The proposed algorithm is called Multi-Scale Top-Hat transform powered by Geodesic Reconstruction for panoramic dental radiography enhancement (MSTHGR). This algorithm is based on multi-scale mathematical morphology techniques. The proposal extracts multiple features of brightness and darkness, through the reconstruction of the marker (obtained by the Top-Hat transformation by reconstruction) starting from the mask (obtained by the classic Top-Hat transformation). The maximum characteristics of brightness and darkness are added to the dental panoramic radiography. In this way, the contrast, details and edges of the panoramic radiographs of teeth are improved. For the tests, MSTHGR was compared with the following algorithms: Geodesic Reconstruction Multiscale Morphology Contrast Enhancement (GRMMCE), Histogram Equalization (HE), Brightness Preserving Bi-Histogram Equalization (BBHE), Dual Sub-Image Histogram Equalization (DSIHE), Minimum Mean Brightness Error Bi-Histogram Equalization (MMBEBHE), Quadri-Histogram Equalization with Limited Contrast (QHELC), Contrast-Limited Adaptive Histogram Equalization (CLAHE) and Gamma Correction (GC). Experimentally, the numerical results show that the MSTHGR obtained the best results with respect to the Contrast Improvement Ratio (CIR), Entropy (E) and Spatial Frequency (SF) metrics. This indicates that the algorithm performs better local enhancements on panoramic radiographs, improving their details and edges.

To determine the influence of periapical lesions on the repeatability of two electronic apex locators (EALs), Root ZX II, and RomiApex A-15, in maxillary anterior teeth, in vivo.After approval by the local ethics committee, 43 maxillary anterior teeth scheduled for root canal therapy were assigned to two groups. The periapical lesion (PAL) group included 21 teeth with necrotic pulps and radiographically visible periapical lesion, and the normal periapex (NPA) group consisted of 22 teeth with vital pulps and no periapical lesion. In each canal, Root ZX II and RomiApex A-15 were used to determine working length defined as the "zero" reading on the display. Two consecutive measurements were performed with each EAL on each tooth and a second operator measured the endodontic file with a digital caliper without knowledge of the EAL being used or the tooth diagnosis. The absolute value of the difference between the first and second measurement (measurement pairs) was calculated. Repeatability was evaluated by the Bland-Altman method, and an aligned ranks transformation ANOVA was conducted to compare the EALs.The median absolute difference between measurement pairs was significantly lower (p0.001) and the limits of agreement were narrower in the NPA group. Among the EALs, median absolute differences were significantly smaller for Root ZX (p0.001).Measurements were more repeatable when no periapical lesion was present. Root ZX showed better repeatability than RomiApex.Periapical lesions seem to influence successive in vivo measurements with EALs.

Resumen Introducción: Los pacientes con trastornos mentales están sometidos a un mayor número de factores de riesgo de enfermedades bucodentales y temporomandibulares. Ello debido a los efectos secundarios de las medicaciones que consumen, la falta de autocuidado, la dificultad para acceder a atención, la actitud hacia los profesionales sanitarios y también la falta de cooperación en los tratamientos dentales. Objetivo: Determinar la frecuencia de los trastornos temporomandibulares (TTM) y el índice de dientes cariados, perdidos y obturados (CPO-D) en pacientes con discapacidad psicosocial crónica internados en el Hospital Psiquiátrico de la ciudad de Asunción, Paraguay. Material y Métodos: El estudio tuvo un diseño observacional descriptivo de corte transversal y fue aprobado por el comité de ética institucional. Participaron 139 personas con discapacidad psicosocial crónica de ambos sexos, mayores de 18 años, en el mes de mayo, 2018. Como instrumentos de medición se utilizaron: un cuestionario de 3 preguntas, el examen clínico con 5 indicadores para la variable presencia de TTM, el odontograma para el índice CPO-D y los expedientes clínicos. Resultados: Se encontró una población en su mayoría masculina, con un rango de edad entre 40-50 años, y un alto porcentaje de fumadores activos. Se observó que el 83,5 % de los examinados presentaba TTM. El índice CPO-D fue 22,8. Entre los signos de TTM, el ruido articular fue el más común. Conclusión: Se observó una elevada frecuencia de TTM en las personas con discapacidad psicosocial y un elevado índice CPO-D. Abstract Introduction: Patients with mental disorders are subject to a greater number of risk factors for oral and temporomandibular diseases. This is due to the side effects of the medication they consume, the lack of self-care, the difficulty in accessing medical help, the attitude of the patients towards health professionals and also the lack of cooperation in their dental treatments. Objective: To determined the frequency of temporomandibular disorders (TMD) and the decayed, missing and filled teeth index (DMFT) in people with chronic psychosocial disability admitted to the Psychiatric Hospital of the city of Asunción. Material and Methods: This descriptive, observational and cross-sectional study was approved by the local ethics committee. One hundred and thirty-nine people with chronic psychosocial disabilities, of both sexes, over 18 years of age participated during May, 2018. The instruments used were a 3-item questionnaire, clinical examination with 5 indicators for presence of TMD, the odontogram for the DMFT index and the clinical charts. Results: A predominantly male population, with an age range between 40-50 years, and a high percentage of active smokers was found. TMD was found in 83.5% and the DMFT index was 22.8. Among the signs of TMD, joint noise was the most common. Conclusion: A high frequency of TMD was observed in people with psychosocial disabilities and a high CPO-D index.

Introduction A greater irrigant volume improves the effectiveness of root canal irrigation. The purpose of this study was to compare 2 negative pressure systems regarding the volume of irrigant collected from the apical area in moderately curved canals at 3 different flow rates of delivery in vitro. Methods The mesiobuccal canals of 30 molars with a curvature between 20° and 40° were prepared to size #40.04 taper. A closed system was created. The canals were irrigated at 3, 6, and 12 mL/min for 30 seconds using EndoVac (SybronEndo, Orange, CA) and the INP needle (Mixnus Fine Engineering Co Ltd, Nagano, Japan) (both independent variables). A recovery trap was used to collect the irrigant aspirated by the negative pressure needles. Irrigant volume (dependent variable) was measured in milliliters. Data were analyzed using mixed analysis of variance. Results There was a statistically significant interaction between the negative pressure system and the irrigant volume collected (P < .0005). The mean irrigant volume collected by the different negative pressure systems was greater for INP at 3 (P < .001), 6 (P < .001), and 12 mL/min (P < .001) flow rate. Both negative pressure needles showed statistically significant differences (P < .001) between mean irrigant volume collected at different flow rates. Conclusions A greater volume was collected by increasing the flow rate of irrigant delivery for both EndoVac and INP. The INP needle could collect a greater volume of irrigant from the apical third compared with EndoVac at all 3 different flow rates. Sin financiación 2.833 JCR (2018) Q1, 12/91 Dentistry, Oral Surgery & Medicine 1.822 SJR (2018) Q1, 5/146 Dentistry (miscellaneous) No data IDR 2018 UEM

This study evaluated the irrigation extrusion and smear layer (SL) removal of continuous ultrasonic irrigation (CUI). Forty root canals were shaped, embedded in warm sterile saline agar colored with 1% acid red, and distributed into four groups; three groups had the final irrigation sequence of sodium hypochlorite and EDTA solutions performed by using syringe irrigation (SI), EndoVac (EV), and CUI, respectively. Group 4 had the canals ultrasonically irrigated with saline (CUIS). Irrigant extrusion was verified by a color change of the agar. The SL was evaluated under scanning electron microscope. Irrigant extrusion was observed in two and four teeth in the CUI and SI, respectively, whilst none had irrigant extruded in the EV. In term of SL, the CUI was comparable to EV at 1 and 3 mm but different to SI at 1 mm. Although CUI might clean the root canal system effectively, it was unable to avoid irrigant extrusion.

El agente irrigante deberia alcanzar la totalidad del conducto radicular, inclusive las zonas mas apicales, para mejor la limpieza y desinfeccion. Sin embargo existe el riesgo de la extrusion del mismo a los tejidos periapicales. El presente estudio con diseno experimental tuvo el objetivo de evaluar la extrusion apical del agente irrigante endodontico de acuerdo a la tecnica de irrigacion durante la irrigacion final en dientes naturales, ex vivo. Se utilizaron 46 dientes anterosuperiores naturales extraidos con conducto unico y las raices se sumergieron en una gelatina conductora incolora. Una aguja de irrigacion/aspiracion fue colocada a 2 mm de la longitud de trabajo y se irrigaron los conductos con una solucion de contraste a 4 ml/min durante 60 s. En 18 dientes se utilizo la tecnica de irrigacion por jeringa y en los 18 restantes se utilizo la tecnica por presion negativa. Los controles positivos y negativos estaban compuestos por 5 dientes cada uno. Se evaluaron presencia y area de extrusion. La prueba Chi2 encontro una asociacion estadisticamente significativa (p

The aim of this study was to determine the effect of nickel titanium file design on the root surface strain generated and apical microcracks caused during canal shaping. Thirty-three mandibular incisors were distributed into LightSpeed X, FlexMaster and a control group. A strain gauge was fixed apically on the proximal root surface to determine the maximum strain during canal shaping. Except for the control group, all root canals were enlarged to size 50. Images were taken after removing the apical 1 and 2 mm of the root end. Mean maximum strain values and presence of microcracks were statistically compared using the t-test and chi-square test, respectively. During canal shaping, the strain increased cumulatively with mean maximum strains of 808.2 ± 228.8 and 525.1 ± 168.9 microstrain in LightSpeed X and FlexMaster, respectively (P = 0.004). Both systems caused comparable microcracks. Although LightSpeed X produced higher maximum strain, no difference in microcrack development was found between both systems.

This study evaluated the irrigation extrusion and smear layer (SL) removal of continuous ultrasonic irrigation (CUI). Forty root canals were shaped, embedded in warm sterile saline agar colored with 1% acid red, and distributed into four groups; three groups had the final irrigation sequence of sodium hypochlorite and EDTA solutions performed by using syringe irrigation (SI), EndoVac (EV), and CUI, respectively. Group 4 had the canals ultrasonically irrigated with saline (CUIS). Irrigant extrusion was verified by a color change of the agar. The SL was evaluated under scanning electron microscope. Irrigant extrusion was observed in two and four teeth in the CUI and SI, respectively, whilst none had irrigant extruded in the EV. In term of SL, the CUI was comparable to EV at 1 and 3 mm but different to SI at 1 mm. Although CUI might clean the root canal system effectively, it was unable to avoid irrigant extrusion.

Adorno CG , Yoshioka T , Jindan P , Kobayashi C , Suda H. The effect of endodontic procedures on apical crackinitiation and propagation ex vivo. International EndodonticJournal, 46, 763–768, 2013. Aim To evaluate the potential effects of endodonticprocedures (instrumentation and filling) on crack ini-tiation and propagation in apical dentine.Methodology Forty extracted single-rooted premo-lars with two canals were selected, 1.5 mm of theapex was ground perpendicular to the long axis ofthe tooth and the surface polished. The specimenswere divided into 4 groups. The buccal canals ofgroups A, B and C were enlarged to size 40 withmanual K-files. Group A was filled with gutta-perchausing lateral condensation and vertical compactionwithout sealer. Group B was filled with the samemethod as group A except only lateral condensationwas used. Group C was left unfilled, while group Dwas left unprepared and unfilled. Images of theresected surface were taken after resection (baseline),after canal preparation, after filling and after 4-weekstorage. The images were then inspected for cracksoriginating from the canal.Results A significant effect of preparation on crackinitiation (P 0.05) or 4-week storage on crack initiation(P > 0.05) was found (logistic regression). Fisher’sexact test revealed a significant effect of filling oncrack propagation (P 0.05).Conclusions Root canal procedures can potentiallyinitiate and propagate cracks from within the rootcanal in the apical region.Keywords: apical root cracks, crack initiation,crack propagation, dentinal cracks, vertical root frac-ture.

The purpose of this study was to compare the formation of microcracks after canal preparation performed with different single-file systems as One Shape (Micro-Mega, Besancon, Cedex, France), F6 SkyTaper (Komet Italia Srl, Milan, Italy), HyFlex EDM (Coltene/Whaledent AG, Altstatten, Switzerland), WaveOne (Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (VDW, Munich, Germany), and WaveOne Gold (Dentsply Maillefer).Eighty-four human extracted mandibular central incisors (40-60 y) were selected and divided into 6 experimental groups (n = 12 teeth) and a control group (unprepared teeth): One Shape (group 1), F6 SkyTaper (group 2), HyFlex EDM (group 3), WaveOne (group 4), Reciproc (group 5), and WaveOne Gold (group 6). Roots were then sectioned at 3, 6, and 9 mm from the apex, and the surface was observed under a stereomicroscope. Data were analyzed using logistic regression (P .05).No cracks were observed in the control group. All the systems tested caused cracks, mainly in the apical section (3 mm). HyFlex EDM (33.3%) and WaveOne Gold (58.3%) showed fewer microcracks than other experimental groups (P .01); however, no significant difference was found between them in crack formation (P .05). There was no difference among the other experimental groups (P .05).All the instruments tested created dentinal cracks. Within the limitations of this study, the flexibility of nickel-titanium instruments because of heat treatment seems to have a significant influence on dentinal crack formation. HyFlex EDM and WaveOne Gold caused less microcracks than the other instruments tested.

Yoshioka T., Kikuchi I., Adorno C.G., Suda H. Periapical bone defects of root filled teeth with persistent lesions evaluated by cone-beam computed tomography. International Endodontic Journal. Aim To evaluate and categorize the bone defects of root filled teeth with persistent periapical lesions by cone-beam computed tomography (CBCT). Methodology Slice images of 532 teeth with persistent periapical lesions were obtained by CBCT in 427 patients and were examined by two endodontists. The periapical lesions were categorized into five types according to the characteristics of the bone defect based on CBCT images. The prevalence of each type was determined and analysed statistically at a 5% significance level using logistic regression. Results Of the 532 teeth analysed, 67% had buccal or labial bone plate defects (type II), 4% palatal or lingual bone plate defects (type III), 7% ‘through and through’ defects (type IV) and 10% apical root protrusions from the bone plate (type V). Mandibular teeth had a significantly greater prevalence of type I lesions (P = 0.0005) and a significantly lower prevalence for types IV (P = 0.041), V (P = 0.001), V-1 (P = 0.015) and V-2 (P < 0.001) as compared to maxillary teeth. Conclusion CBCT accurately identified the type of periapical bone defect in persistent lesions. Because 10% of the teeth had apical root protrusions, which could not be identified by periapical radiography, the diagnostic information obtained by CBCT was an essential component of the treatment planning process.

Higa RA, Adorno CG, Ebrahim AK, Suda H. Distance from file tip to the major apical foramen in relation to the numeric meter reading on the display of three different electronic apex locators. International Endodontic Journal, 42, 1065‐1070, 2009. Aim To establish and compare the relationship between the distance from the file tip to the apical foramen and the numeric meter reading on the display of three different electronic apex locators (EALs). Methodology A total of 12 extracted intact, straight, single-rooted human teeth with complete roots were used. The actual root canal length (AL) was determined after access preparation. For the electronic measurements with each EAL, silicon stops were fixed with auto-polymerizing resin to size 15 K-files at AL and 0.5, 1, 2, 3, 4 mm short of AL. The data was analysed by two-way anova and Tukey’s honestly significant difference (HSD) test for multiple comparisons amongst EALs. Additionally, one-way anova and Tukey’s HSD test were carried out for multiple comparisons amongst the measurements of each EAL. Results There was a statistically significant difference amongst all EALs in indicating the position of file tips in relation to the major foramen (P < 0.05). The correlation between the meter reading and the position of the file tip from the apical foramen was statistically significant in the three EALs. There were significant differences amongst the measurements at distances from 0 to 2 mm in Justy III. In Dentaport, significant differences were found from 0 to 1 mm. However, the E-Magic Finder showed significant differences from 0 to 0.5 mm. Conclusions Justy III was more capable of displaying the intracanal position of the file tip from the major foramen in mm whilst advancing through the root canal during electronic measurements than the Dentaport and E-Magic Finder Deluxe.

The aim of this study was to determine the effect of nickel titanium file design on the root surface strain generated and apical microcracks caused during canal shaping. Thirty-three mandibular incisors were distributed into LightSpeed X, FlexMaster and a control group. A strain gauge was fixed apically on the proximal root surface to determine the maximum strain during canal shaping. Except for the control group, all root canals were enlarged to size 50. Images were taken after removing the apical 1 and 2 mm of the root end. Mean maximum strain values and presence of microcracks were statistically compared using the t-test and chi-square test, respectively. During canal shaping, the strain increased cumulatively with mean maximum strains of 808.2 ± 228.8 and 525.1 ± 168.9 microstrain in LightSpeed X and FlexMaster, respectively (P = 0.004). Both systems caused comparable microcracks. Although LightSpeed X produced higher maximum strain, no difference in microcrack development was found between both systems.

This ex vivo study evaluated the irrigation efficacy of a new apical negative pressure system (ANP) in canals with simulated immature teeth, by comparing it to EndoVac (EV) system in terms of smear layer (SL) removal and irrigation extrusion.Three millimetres of the root end of 40 single canalled lower incisors were resected and decoronated to standardize root canal length. After instrumentation, the specimens were embedded in warm normal saline agar coloured with 1 % acid red and randomly divided into four groups; one control group and three experimental groups. Except in the control group where distilled water was used as irrigant using positive pressure irrigation needle, the canals were irrigated with 6 % NaOCl and 17 % EDTA using the intracanal negative pressure needle (iNP) system, the EV system or 27G open-ended needle under positive pressure (PP). NaOCl extrusion was determined by observing a discolouration of the agar surrounding the root. The SL was evaluated by observing scanning electron microscope images based on a four-level scoring system.Two specimens with irrigant extrusion were observed in the iNP group, which was significantly different (logistic regression, p 0.05) to EV and PP. There were no significant differences (Kruskall-Wallis test, p 0.05) among the experimental groups in terms of SL removal, but all were significantly different to the control group.Irrigation with the iNP could be a viable alternative to EV as an apical negative pressure irrigation technique especially while treating immature teeth.ANP in canal cleanliness is recommended to be utilized in treating immature teeth where periapical tissues should be saved and stimulated. The iNP system might have the potential to avoid irrigant extrusion while cleaning the canal till the apical end.

Aim To compare in a laboratory study two negative pressure systems and syringe irrigation, regarding the delivery of a contrast solution (CS) to working length (WL) and into simulated lateral canals and the effective volume of irrigant aspirated during negative pressure irrigation. Methodology Twenty single-canaled incisor training models were constructed with six simulated lateral canals each (2, 4 and 6 mm to WL) and a size 40, 0.04 taper apical size canal. Each model underwent all irrigation procedures (EndoVac at WL (EndoVac-0) and WL–2 mm (EndoVac-2), iNP needle with negative pressure (iNPn) and syringe irrigation with the iNP needle (iNPs) and a 30-G side-slot needle placed at WL (SI0) and WL–2 (SI2) mm in a crossover design. CS was delivered at 4 mL min−1 for 60 s with a peristaltic pump and a recovery device collected the volume (in mL) of irrigant suctioned by the negative pressure groups. The irrigation procedures were digitally recorded, and a still image of the 60-s time-point of irrigation was evaluated for CS distance to WL (in millimetres) after irrigation and penetration into lateral canals (3-point scale). Statistical tests used were Kruskal–Wallis and Dunn's test. Results EndoVac-0, iNPn and iNPs had median distances of CS to WL of 0 mm, followed by SI0 (0.2 mm), SI2 (0.7 mm) and EndoVac-2 (1.7 mm). There were no significant differences between EndoVac-0, iNPn, iNPs and SI0, but these were significantly different to SI2 and EndoVac-2 (P

Introduction The aim of this study was to compare the effects of three brands of nickel-titanium (NiTi) rotary files with different designs on the initiation of apical root cracks when working short, at, and beyond the apical foramen. Methods One-hundred eight teeth with straight single canals were selected and mounted on resin blocks with simulated periodontal ligaments, and the apex was exposed. The teeth were divided into 9 groups of 12 teeth according to the NiTi rotary file type used (Profile [Dentsply Maillefer, Ballaigues, Switzerland], K3 [SybronEndo, West Collins, CA], and EndoWave [FKG Dentaire, La-Chaux-de-Fonds, Switzerland]) and working length (at CL, 1 mm short of [CL – 1 mm], and 1 mm beyond [CL + 1 mm] the apical foramen). Digital images of the apical surface of every tooth were taken during the apical enlargement sequence at each file change. These images were compared with the baseline image, and the presence of a crack was noted. Results Significantly less cracks were observed in the CL – 1 mm group than in the CL and CL + 1 mm groups. No significant difference was found between the file types used. Conclusions Working 1 mm short of the apical foramen caused less cracks on the apical surface. In addition, more cracks were observed when using larger file sizes. Instrumentation with NiTi rotary files could potentially cause cracks on the apical root surface.

Adorno CG, Yoshioka T, Suda H. Incidence of accessory canals in Japanese anterior maxillary teeth following root canal filling ex vivo. International Endodontic Journal, 43, 370–376, 2010. Abstract Aim To investigate the vertical and horizontal distribution and the incidence of accessory canals in Japanese maxillary anterior teeth following root filling. Methodology The study included maxillary teeth; 69 central incisors, 61 lateral incisors and 31 canines. After the canal systems had been dyed and root canal instrumentation had been carried out, all prepared canals were filled with gutta-percha without using sealer. Transparent specimens were then obtained and examined with a digital microscope for horizontal and vertical distributions of accessory canals. Results The incidence of teeth with accessory canals in the apical 3 mm was 46%, 29% and 38% for the maxillary central incisors, lateral incisors and canines, respectively. The horizontal distribution was mainly buccal for central incisors, palatal for lateral incisors and distal and palatal for canines. There was a significant difference (P

The purpose of this study was to compare the effects of root canal preparation techniques and instrumentation length on the development of apical root cracks. Forty extracted mandibular premolars with straight roots were randomly selected and mounted on resin blocks with simulated periodontal ligaments, and the apex was exposed. The teeth were divided into four groups of 10 teeth each for different canal preparation techniques and instrumentation lengths: group A: step-back preparation (SB) with stainless steel files (SF) using root canal length (RCL) to guide instrumentation length; group B: SB using RCL - 1 mm; group C: crown-down preparation (CD) with Profile using RCL; and group D: CD with PF using RCL - 1 mm. Digital images of the instrumentation sequence were compared for each tooth. Statistical analysis revealed a significant effect of instrumentation length (p0.05) but no significant effect of preparation technique (p0.05) on the development of apical cracks.

Resumen Introducción: los profesionales en odontología han sido identificados como de muy alto riesgo de exposición al coronavirus, específicamente cuando llevan a cabo procedimientos de generación de aerosoles en pacientes infecciosos. El objetivo fue conocer los mecanismos mecánicos y químicos usados por los odontólogos paraguayos para evitar la propagación del COVID-19. Evaluar el porcentaje de odontólogos que hayan atendido pacientes COVID positivo y que posteriormente hayan desarrollado la enfermedad. Métodos: estudio observacional descriptivo de corte transversal. Participaron del estudio odontólogos paraguayos con acceso a internet. La difusión del enlace de acceso se realizó por redes sociales. Se recolectaron datos sociodemográficos y medidas de protección utilizadas en el consultorio a fin de disminuir el riesgo biológico. Resultados: participaron 428 odontólogos, 84,11 % fueron mujeres, 38,32 % tenía de 30-39 años. Las medidas de desinfección y cuidados más utilizadas fueron la desinfección del sillón dental (96,7 %), lavado de manos del profesional (93,46 %) y desinfección de superficies con alcohol 70 (88,08 %). El 59,1% utilizaba el peróxido de hidrógeno al 1% como enjuague bucal preoperatorio. La mayoría utilizaba tapabocas KN95 (48,83%), bata de tela tejida (78,04 %), bata desechable (72,20%); uso de gorrito (89,49%) y/o cubre calzado (76,40 %) por parte del paciente, y esterilizan en autoclave sus instrumentales (82,48%). Un profesional relató haberse contagiado en el consultorio odontológico. Conclusión: La mayoría de los odontólogos paraguayos encuestados cumple con los protocolos establecidos por el Ministerio de Salud y organismos internacionales, los cuales aparentan ser efectivos como mecanismos de protección contra el COVID-19 en el ambiente clínico. Abstract Introduction: dental professionals have been identified as having a very high risk of exposure to coronavirus, specifically when they carry out procedures to generate aerosols in infectious patients. The objective was identifying the mechanical and chemical mechanisms used by Paraguayan dentists to prevent the spread of COVID-19. Evaluate the percentage of dentists who have treated positive COVID patients and who have subsequently developed the disease. Methods: it was a cross-sectional descriptive observational study. Paraguayan dentists with internet access participated. The questions were about sociodemographic data and protection measures used in the office to reduce biological risk. The access link was disseminated through social networks. Results: 428 dentists participated in the study, 84.11 % were women, 38.32 % were 30-39 years old. The most used disinfection and care measures were dental chair disinfection (96.7 %), hand washing (93.46 %) and surface disinfection with alcohol 70 (88.08 %). 59.1% used 1% hydrogen peroxide as a preoperative mouthwash. The majority wore KN95 masks (48.83 %), woven cloth robe (78.04 %), disposable robe (72.20 %); The patient is fitted with a disposable surgeon’s cap (89.49 %) and/or shoe covers (76.40 %), and their instruments are sterilized in an autoclave (82.48%). One professional reported having been infected in the dental office. Conclusion: most of the Paraguayan dentists surveyed comply with the protocols established by the Ministry of Health and international organizations, which appear to be effective as protection mechanisms against COVID-19 in the clinical environment.