Correlation Between Quality Evaluation Metrics and Teeth Detection Results in Panoramic X-Rays Using Deep Learning.

Panoramic images are one of the most requested exams by dentists for allowing the visualization of the entire mouth. Interpreting X-ray images is a time-consuming task in which misdiagnoses can occur due to the inexperience or fatigue of professionals. In this work, we applied different image enhancement techniques as a pre-processing step to determine which image features correlate with improvements in teeth detection in panoramic images using deep learning architectures. We contrasted the performance of five object-detection architectures using 300 panoramic images of a public dataset. We evaluated the enhancement in the pre-processing step and the detection performance. Quality and detection metrics were considered, and the cross-correlation between them was computed for every object-detection method contemplated. We observe the dependence of the detection performance with some image enhancement techniques, especially those that introduce less noise and preserve the global contrast of the image.

Frecuencia de la posición, inclinación y grado de dificultad quirúrgica de terceros molares mandibulares en pacientes que acuden a la Facultad de Odontología de la Universidad Nacional de Asunción

RESUMEN La disposición que puede adoptar un tercer molar mandibular resulta en la mayoría de los casos impredecible. Para facilitar el análisis de la posición e inclinación de los terceros molares autores como Pell-Gregory y Winter, establecieron una clasificación de esas piezas dentarias para guiar la técnica operatoria más adecuada para cada situación. El objetivo fue determinar la frecuencia de la posición, inclinación y grado de dificultad quirúrgica en terceros molares mandibulares. El estudio fue observacional descriptivo, retrospectivo de corte transversal. Formaron parte del estudio radiografías panorámicas de pacientes que acudieron a la Facultad de Odontología UNA entre el 2018 y 2020. Un total de 220 radiografías panorámicas fueron incluidas en el estudio, 120 (54,5%) correspondían al sexo femenino y 100 (45,4%) al sexo masculino, la franja etaria de 18 a 28 años fue la de más participación con 134 (61%) radiografías. Se evidenció una frecuencia en la posición A clase II de 141 (36,6%), en cuanto a la inclinación de las piezas dentarias, la más frecuente fue la mesioangular 174 (45,5%) y en cuanto al grado de dificultad quirúrgica se observó una dificultad mínima a moderada. Se evidenció una frecuencia alta de la posición A clase II e inclinación mesial del total de las radiografías analizadas.

ABSTRACT The position a mandibular third molar can adopt is unpredictable in most cases. To facilitate the analysis of the position and inclination of third molars, authors such as Pell-Gregory and Winter established a classification of these teeth to guide the most appropriate surgical technique for each situation. The objective was to determine the frequency of the position, inclination and degree of surgical difficulty in mandibular third molars. The study was descriptive, retrospective, cross-sectional, and observational. Panoramic radiographs of patients who attended the School of Dentistry of the National University of Asuncion between 2018 and 2020 were part of the study. A total of 220 panoramic radiographs were included in the study, 120 (54.5%) corresponded to women and 100 (45.4%) to men, the age group from 18 to 28 years old had the most participation with 134 (61%) radiographs. A frequency in position A class II of 141 (36.6%) was evidenced, while in terms of the inclination the mesioangular was the most frequent, 174 (45.5%) and in terms of the degree of surgical difficulty, minimal to moderate difficulty was observed. A high frequency of position A class II, mesial inclination was evidenced in all the radiographs analyzed.

Influence of different calcium hydroxide removal protocols on the bond strength of epoxy resin-based sealer in long oval root canals.

This study evaluated the effect of different protocols for Ca(OH)2 removal on the bond strength (BS) of epoxy resin-based sealer in long oval root canals. Forty-eight mandibular incisors with long oval root canals were selected by CBCT. Biomechanical preparation was performed, the samples were filled with Ca(OH)2 paste and distributed in four groups (n = 12): G-without Ca(OH)2 paste (C); G2-syringe/needle (SN); G3-SN + XP-Endo® Finisher (XPF); G4-SN + passive ultrasonic irrigation (PUI). After 7 days, Ca(OH)2 was removed and teeth were filled using AHPlus and guttapercha. In four samples from each group, the sealer was manipulated with 0.1% rhodamine to assess sealer penetration by fluorescent laser confocal microscopy (FLCM). Samples were sectioned in slices for BS, scanning electron microscopy, and FLCM analysis. The BS data were analyzed by ANOVA and Tukey tests (α = 0.05). The lowest BS values were found for the SN group (12.89 ± 4.36) compared to C (35.55 ± 10.05), while PUI group presented intermediate values (28.57 ± 9.35) and the XPF group (31.34 ± 9.8) showed values that were sometimes similar to C group and sometimes similar to PUI group (p > .05). The analysis of the adhesive interface showed evident gaps, with the presence of residues between the dentin and the filling material for the SN group, and for C, XPF and PUI groups juxtaposed adhesive interface. FLCM images showed sealer penetration in the dentinal tubules along the entire perimeter for C, XPF, and PUI groups. Ca(OH)2 removal with XPF and PUI from long oval root canals resulted in higher bond strength values compared to SN, besides better sealer penetration on dentinal tubules and juxtaposed adhesive interface.

Medidas empleadas por odontólogos paraguayos para disminuir el riesgo biológico en la práctica odontológica durante la pandemia de Covid-19 / Infection control procedures used by Paraguayan dentists to reduce biological risk in dental practice during the Covid-19 pandemic

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.

Sustracción Radiográfica Digital de la Estructura Dentaria Removida Durante el Acceso Endodóntico En Incisivos Mandibulares

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.

ABSTRACT: The aim of this study was to compare the area of tooth structure removed during two different endodontic access techniques in lower incisors. Thirty-two extracted lower incisors were weighed individually on a precision scale. After initial digital radiographs were taken from buccal and proximal, the teeth were coded and randomly assigned to two different groups: conventional access and incisal access. Once this stage was completed, each tooth was weighed again and 2 postoperative radiographs was taken again, buccal and proximal. Using an image processing software and digital subtraction technique, 2 independent and calibrated evaluators measured difference in tooth structure after access procedures. Interobserver agreement was almost perfect: intraclass correlation coefficient equal to 0,94 and 0,98 for proximal and buccal incidences, respectively. The Mann-Whitney test found statistically significant differences between the types of accesses in terms of weight difference (p = 0.0073) and area VL (p = 0.0023). Additionally, a statistically significant difference between the types of access in the MD area (Welch's t test, p <0.005) was observed. The difference in weight was less for incisal access than for conventional access with a statistically significant difference, in terms of MD and VL area, incisal access and areas of smaller size than conventional access.

Panoramic Dental Radiography Image Enhancement Using Multiscale Mathematical Morphology.

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.

The influence of periapical lesions on the repeatability of two electronic apex locators in vivo.

OBJECTIVES: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: Measurements were more repeatable when no periapical lesion was present. Root ZX showed better repeatability than RomiApex. CLINICAL RELEVANCE: Periapical lesions seem to influence successive in vivo measurements with EALs.

[Application of the dental trauma guide of the international association of dental traumatology in a group of paraguayan dentists]. / Aplicación de la guía de trauma dental de la asociación internacional de traumatología dental en un grupo de odontólogos paraguayos.

Objective: To evaluate the application of the dental trauma guide according to the International Association of Dental Traumatology in a group of Paraguayan dentists from April to May 2021. The was a descriptive, cross-sectional, observational study. A group of Paraguayan dentists with internet access accepted to participate in the study. The measurement instrument was a closed questionnaire from Google Forms, distributed by instant messaging (WhatsApp) from January to April 2021. Based on the Guidelines for the Evaluation and Management of Traumatic Dental Injuries by the International Association of Dental Traumatology (IADT), the questionnaire includes 20 questions on the assessment of clinical and radiographic signs, determination of treatment variables, differentiation of the type of treatment, biological consequences of trauma, materials and splint time, and postoperative indications and medication. Results: 230 dentists participated; the mean age was 33 (SD = 6.4) years, 70.43% were women, 30.87% were general dentists, and 70.87% were practicing exclusively in private practice. 68.70% responded that they were familiar with the management and treatment of dentoalveolar trauma, while 70.87% had not heard or read about the IADT dental trauma guide. Regarding the level of knowledge, 60.00% scored an average mark. Conclusion: Most of the dentists surveyed had moderate knowledge regarding the evaluation and management of traumatic dental injuries.

Estudio preliminar sobre la repetibilidad in vivo de tres localizadores apicales electrónicos / Preliminary study about in vivo repeatability of three electronic apex locators

RESUMEN Introducción: La mayoría de los estudios han evaluado y comparado la exactitud de los localizadores apicales electrónicos pero pocos evaluaron la repetibilidad del método de medición; de estos casi todos son ex vivo. Objetivo: Comparar la repetibilidad in vivo de tres localizadores apicales electrónicos en dientes antero-superiores permanentes. Métodos: Se realizó un estudio observacional analítico de corte transversal en 14 pacientes adultos sanos de ambos sexos con indicación de tratamiento de conductos en una pieza dentaria antero-superior. La selección fue por casos consecutivos. Se utilizaron tres localizadores apicales electrónicos (Root ZX II, Canal Pro y RomiApex A-15) para realizar las mediciones de los conductos. Dos operadores independientes realizaron dos mediciones con cada localizador apical electrónico. Los datos se analizaron por medio de la prueba de Bland-Altman para la repetibilidad y la prueba de Friedman para comparar los localizadores apicales. Resultados: La edad media (desviación estándar) de los pacientes fue 28,79 (± 9,12) años; 8 (57,1 por ciento) pacientes fueron del sexo femenino. La media de las diferencias (límites de concordancia) de las mediciones para Root ZX, Canal Pro y RomiApex A-15 fueron 0,13 mm (± 0,42), 0,12 mm (± 0,88), y 0,18 (± 0,76) mm, respectivamente. Conclusiones. El Root ZX presentó el mayor grado de repetibilidad, seguido por el RomiApex. No se encontraron diferencias estadísticamente significativas entre los localizadores en cuanto a las diferencias absolutas entre la 1ra y 2da mediciones(AU)

ABSTRACT Introduction: Most studies have evaluated and compared the accuracy of electronic apex locators, but few have addressed the repeatability of the measurement method, and most are ex vivo. Objective: Compare the in vivo repeatability of three electronic apex locators in permanent upper front teeth. Methods: An analytic observational cross-sectional study was conducted of 14 healthy adult patients of both sexes with root canal therapy indicated in an upper front tooth. The consecutive case method was used to select the patients. Three electronic apex locators (Root ZX II, Canal Pro and RomiApex A-15) were used for root canal measurement. Two independent operators performed two measurements with each electronic apex locator. Data were analyzed using the Bland-Altman test to assess repeatability and the Friedman test to compare the apex locators. Results: Mean age (standard deviation) of the patients was 28.79 (± 9.12) years; 8 patients (57.1 percent) were female. The mean differences (limits of agreement) of the measurements made by Root ZX, Canal Pro and RomiApex A-15 were 0.13 mm (± 0.42), 0.12 mm (± 0.88) and 0.18 (± 0.76) mm, respectively. Conclusions: Root ZX displayed the highest repeatability, followed by RomiApex. Statistically significant variations were not found between the locators as to absolute differences between the 1st and 2nd measurement(AU)