Frecuencia y tipología del segundo conducto mesiovestibular en primeros molares superiores / Frequency and typology of the second mesiobuccal canal in maxillary first molars

Objetivos: Evaluar mediante microscopia quirúrgica la presencia del segundo conducto mesiovestibular (MV2) en el piso de la cámara pulpar de los primeros molares superiores, determinar su abordabilidad, establecer el calibre de lima que llegó al tercio apical y tipificar radiovisiográficamente su morfología se-gún la clasificación de Weine. Materiales y métodos: Se utilizaron 48 primeros molares superiores huma-nos extraídos. Sé tomaron radiovisografías preope-ratorias (Carestream 5200) en sentido orto radial y mesio-distal. Se realizó apertura y se localizó entra-da del MV2 con microscopio quirúrgico (Newton MEC XXI, Argentina) a 16 x. Se cateterizó MV1 y MV2 con limas tipo K #10 y #15 (Dentsply Maillefer). Se cortó raíz distovestibular para mejorar visualización ra-diovisográfica. Se tomó conductometria en sentido mesio-distal para establecer la tipología. Se compa-raron frecuencias y porcentajes mediante test de Chi-cuadrado con corrección de Yates, prueba exac-ta de Fisher y test z para diferencia de proporcio-nes. Se calcularon intervalos de confianza 95% para porcentajes mediante método score de Wilson. Re-sultados: El 54% (26 casos) presentó MV2. De los 26 MV2, el 77% (20 casos) fueron abordables, porcen-taje significativamente mayor al 23% no abordable (z=3,62; P<0,05). Al hacer cateterismo, hubo asocia-ción significativa entre tipo de conducto (MV1 y MV2) y calibre de lima que llegó al tercio apical (Chi-cua-drado=29,12; gl=1; P<0,05). La tipología I (58%) fue significativamente mayor que las tipologías II (21%) y III (21%) (P<0,05 para ambas comparaciones). Con-clusión: El alto porcentaje de piezas que presentó MV2 evidencia la importancia clínica de detectarlo y tratarlo correctamente. Dado el alto porcentaje de piezas donde fue abordable, se concluye que el clíni-co debe tener conocimiento, destreza y la tecnología necesaria para poder abordarlo. Si bien la tipología I (58%) fue la más encontrada, cuando el MV2 termina en foramen independiente (tipo III), su omisión puede conducir al fracaso del tratamiento (AU))

Objectives: To evaluate by surgical microscopy the presence of second mesiobuccal canal (MB2) in the pulp chamber floor of the maxillary first molars, determine its approachability, establish the caliber of the file that reached the apical third, and radiographically typify its morphology according to Weine ́s classification. Materials and methods: 48 extracted human maxillary first molars were used. Preoperative radiovisographies (Carestream 5200) were taken in ortho-radial and mesio-distal direction. Coronal access was made and the entrance of MB2 was located with a surgical microscope (Newton MEC XXI, Argentina) at 16x. MB1 and MB2 were catheterized with K files #10 and #15 (Dentsply Maillefer). Distobuccal root was cut to improve radiovisographic visualization. Conductometry was taken in mesio-distal direction to establish the typology. Frequencies and percentages were compared using Chi-square test with Yates correction, Fisher's exact test and z test for difference in proportions. 95% confidence intervals were calculated for percentages using Wilson score method. Results: 54% (26 cases) presented MB2. Of the 26 MB2, 77% (20 cases) were approachable, a significantly higher percentage than those not approachable (z=3.62; P<0.05). When performing catheterization, there was a significant association between type of canal (MB1 and MB2) and file caliber that reached the apical third (Chi-square=29.12; df=1; P<0.05). Typology I (58%) was significantly higher than typologies II (21%) and III (21%) (P<0.05 for both comparisons). Conclusion: The high percentage of specimens that showed MB2 evidence the clinical importance of detecting and treating it correctly. Given the percentage of pieces where it was approachable (77%), it is concluded that the clinician must have the knowledge, skill and necessary technology to be able to approach it. Although typology I (58%) was the most found, when MB2 ends an independent foramen (type III), its omission can lead to treatment failure (AU)

Analysis of the Internal and External Morphology of the Mandibular First Molar in a Chilean Sub-Population Using Cone-Beam Computed Tomography / Análisis de la Morfología Interna y Externa del Primer Molar Mandibular en una Subpoblación Chilena Mediante Tomografía Computarizada de Haz Cónico

SUMMARY: The mandibular first molar (MFM) commonly presents two roots with two canals in the mesial root and one or two canals in the distal root. However, morphological variations have been described in different populations, which must be considered when planning endodontic treatment. The aim of this study was to analyze the internal and external morphology of the MFM in a Chilean sub-population using cone-beam computed tomography (CBCT) images. An in vivo cross-sectional, descriptive, and observational study was conducted using CBCT exams from 351 right and left MFM. The data were analyzed by descriptive statistics using the Chi- Square test for categorical variables, Fisher's exact test, the Mann-Whitney U non-parametric test for two independent samples, and the Wilcoxon non-parametric test for related samples. Of the total sample, 1 root was observed in 2.27 % of the cases, 2 roots in 93.73 %, and 3 roots in 4 %. In relation to the number of canals, 71.23 % of the MFM showed 3 root canals, 16.81 % 4 canals, 9.69 % 2 canals, and 2.28 % 1 canal. Of all the studied cases, 2.3 % had a C-shaped anatomy. In terms of morphology, using Zhang's classification, variant 3 was observed in 71.23 %, variant 4 in 12.82 %, variant 1 in 9.67 %, variant 6 in 4 %, and variant 8 in 2.28 %. In conclusion, the morphology of the MFM is variable in a Chilean sub-population, and these variations must be considered before and during endodontic therapy. CBCT proved to be an effective tool for the in vivo study of tooth morphology.

El primer molar mandibular (MFM) comúnmente presenta dos raíces con dos canales en la raíz mesial y uno o dos canales en la raíz distal. Sin embargo, se han descrito variaciones morfológicas en distintas poblaciones, las que se deben tener en consideración al momento de planificar el tratamiento endodóntico. El objetivo de este estudio fue analizar la morfología interna y externa del MFM en una sub población chilena mediante el uso de imágenes de tomografía computarizada Cone Beam (CBCT). Se realizó un estudio transversal, descriptivo y observacional in vivo empleando exámenes CBCT de 351 MFM tanto derechos como izquierdos. Los datos se analizaron mediante estadística descriptiva empleando la prueba Chi-Cuadrado para variables categóricas, el test exacto de Fisher, la prueba no paramétrica de U-Mann-Whitney para dos muestras independientes y la prueba no paramétrica de Wilcoxon para muestras relacionadas. Del total de la muestra se observó 1 raíz en un 2.27 % de los casos, 2 raíces en 93.73 % y 3 raíces en un 4 %. En relación al número de canales un 71.23 % de los MFM mostraron 3 canales radiculares, un 16.81 % 4 canales, un 9.69 % 2 canales y un 2.28 % 1 canal. Del total de los casos estudiados un 2.3 % se presentó anatomía en forma de C. En relación a la morfología, empleando la clasificación de Zhang, se observó en un 71.23 % la variante tipo 3, en un 12.82 % la variante tipo 4, en un 9.67 % la variante tipo 1, en un 4 % variante tipo 6 y en un 2,28 % variante tipo 8. En conclusión, la morfología del MFM es variable en una subpoblación chilena y estas variaciones deben ser consideradas antes y durante la terapia endodóntica. El CBCT demostró ser una herramienta eficaz para el estudio in vivo de la morfología dentaria.

Cone beam computed tomography-based evaluation of the relationship between the inferior alveolar canal and the cortical plates and the mandibular molar roots in the saudi subpopulation / Evaluación basada en tomografía computarizada de haz cónico de la relación entre el canal alveolar inferior y las placas corticales y las raíces de los molares mandibulares en la subpoblación saudita

Aim: To assess the distance between the inferior alveolar canal and the roots of the mandibular second molar and the mandibula and cortex in a Saudi Arabian subpopulation through existing CBCT images. Materials and Methods: This retrospective study was performed based on 120 patients CBCT images in five age groups.The distances (D1 and D2) between the buccal cortex (BC), lingual cortex (LC), and mandibular molars and the distances (D3) between the root apices and inferior alveolar nerve canal (IANC) were measured for each dental root on the right and left of the mandible with the help of Vision iCAT software. A radiology specialist with a gap of 15 days twice carried out the measurements. Statistical analysis was carried out with the help of SPSS 24. to analyse variability Chi-square analysis was done, and the p value was fixed at > 0.05. To check inter-person variability, Cohen's variability was fixed at 0.8. Results: The distance between the outer surface of the buccal cortical plate and the buccal root surface ranged between 3.8 and 5.7 mm, whereas the distance between the root apices of the mandibular molars and the IANC ranged between 4.8 and 3.5 mm. The distance from the outer surface of the lingual cortical plate to the lingual root surface varied between 1.2 and 2.8 mm. The mean distance between the root apices and IANC increased with age, more so in males than females. Conclusions: Even though this study was conducted on a small sample size, it will help the dental practitioners in planning endodontic procedures, surgical extractions, and implant placements, and it should be repeated with a higher number of images.

Objetivo: Evaluar la distancia entre el canal alveolar inferior y las raíces del segundo molar mandibular, y la mandíbula y la corteza en una subpoblación de Arabia Saudita a través de imágenes CBCT existentes.Materiales y Métodos: Este estudio retrospectivo se realizó con base en imágenes CBCT de 120 pacientes en cinco grupos de edad. Las distancias (D1 y D2) entre la corteza bucal (BC), la corteza lingual (LC) y los molares mandibulares y las distancias (D3) entre los Se midieron los ápices radiculares y el canal del nervio alveolar inferior (IANC) para cada raíz dental a la derecha e izquierda de la mandíbula con la ayuda del software Vision iCAT. Un especialista en radiología, con un intervalo de 15 días, realizó dos veces las mediciones. El análisis estadístico se realizó con la ayuda del SPSS 24. Para analizar la variabilidad se realizó un análisis de Chi-cuadrado y el valor p se fijó en > 0,05. Para comprobar la variabilidad entre personas, la variabilidad de Cohen se fijó en 0,8. Resultados: La distancia entre la superficie exterior de la placa cortical bucal y la superficie de la raíz bucal osciló entre 3,8 y 5,7 mm, mientras que la distancia entre los ápices radiculares de los molares mandibulares y el IANC osciló entre 4,8 y 3,5 mm. La distancia desde la superficie exterior de la placa cortical lingual hasta la superficie de la raíz lingual varió entre 1,2 y 2,8 mm. La distancia media entre los ápices de las raíces y la IANC aumentó con la edad, más en hombres que en mujeres. Conclusión: Aunque este estudio se realizó con un tamaño de muestra pequeño, ayudará a los odontólogos a planificar procedimientos de endodoncia, extracciones quirúrgicas y colocación de implantes, y debe realizarse con más números.

Has the literature thoroughly categorized the lower third molars? A new classification of the various lower third molar root forms for a better understanding of their morphology / ¿La literatura ha categorizado minuciosamente los terceros molares inferiores? Una nueva clasificación de las diversas formas radiculares del tercer molar inferior para una mejor comprensión de su morfología

SUMMARY: Impacted lower third molars (IL3M) have different root shapes and numbers. This study aimed to create a classification for IL3M root forms, that should aid in understanding roots morphology. A retrospective cross-sectional study on patients had IL3M at the university clinics between 2017 and 2019. Panoramic radiographs were retrieved to classify the roots into fused roots (FR): one or two roots connected from furcation to apices, and separated roots (SR): two or more roots not connected from furcation to apical third, and each type has different forms. Statistical analysis was done by Chi-Square test. Five-hundred patients, males (54.6 %) and females (45.4 %) were included. SR were in 591 teeth (75.5 %), and FR in 192 teeth (24.5 %). Statistically significant associations emerged between SR and males (60 %) and between FR and females (66 %) (p = .000). SR forms were straight (45.8 %), joined roots (28.2 %), one straight and one curved (13.3 %), roots curved distal (9.1 %), roots curved mesial (2.5 %), and more than two roots (0.3 %). FR forms were straight (87.5 %), curved distal (9.4 %), S-shaped (2.1 %), and curved mesial (1 %). The common angulations of IL3M with SR were vertical (39 %) followed by mesioangular (25.7 %), while FR were mostly vertical (39.1 %) or horizontal (23.9 %). The classification is applicable on panoramic radiographs, and complements Winter and Pell & Gregory to provide a better description of IL3M status by adding root morphology to the angulation, occlusal, and ramus relationship.

Los terceros molares inferiores impactados (3MII) tienen diferentes formas y números de raíces. Este estudio tuvo como objetivo crear una clasificación para las formas de raíz 3MII, que debería ayudar a comprender la morfología de las raíces. Realizamos un estudio transversal retrospectivo de pacientes con 3MII en las clínicas universitarias entre 2017 y 2019. Se recuperaron radiografías panorámicas para clasificar las raíces en raíces fusionadas (RF): una o dos raíces conectadas desde la zona de furca a los ápices y raíces separadas (RS): dos o más raíces no conectadas desde la bifurcación al tercio apical, y cada tipo con formas diferentes. El análisis estadístico se realizó mediante la prueba Chi-Cuadrado. Se incluyeron 500 pacientes, hombres (54,6 %) y mujeres (45,4 %). RS se observó en 591 dientes (75,5 %) y RF en 192 dientes (24,5 %). Surgieron asociaciones estadísticamente significativas entre RS y hombres (60 %) y entre RF y mujeres (66 %) (p = .000). Las formas de RS eran rectas (45,8 %), raíces unidas (28,2 %), una recta y una curva (13,3 %), raíces curvas distales (9,1 %), raíces curvas mesiales (2,5 %) y más de dos raíces (0,3 %).). Las formas RF eran rectas (87,5 %), curvas distales (9,4 %), en forma de S (2,1 %) y curvas mesiales (1 %). Las angulaciones comunes de 3MII con RS fueron verticales (39 %), seguidas de mesioangular (25,7 %), mientras que RF fueron mayoritariamente verticales (39,1 %) u horizontales (23,9 %). La clasificación es aplicable en radiografías panorámicas y complementa a Winter y Pell & Gregory para proporcionar una mejor descripción del estado de 3MII al agregar la morfología de la raíz a la relación de angulación, oclusal y rama.

Prevalence of radix entomolaris in mandibular first molars by cone-beam computed tomography in a southern Chilean sub-population / Prevalencia de radix entomolaris en primeros molares mandibulares usando tomografía computarizada cone-beam en una subpoblación del sur de Chile

SUMMARY: The aim of this of this study was to evaluate the prevalence and morphology of radix entomolaris (RE) in the mandibular first molar (MFM) in a southern Chilean sub-population by cone-beam computed tomography (CBCT). Two hundred ten CBCT images of MFM were analysed. To detect the presence of RE, the observation and measurements were standardised, advancing 1 mm to apical from the floor of the pulp chamber to the most apical zone of the tooth. The data were analyzed using descriptive statistics, with a value of P < 0.05 being statistically significant. The prevalence of a third root in the permanent MFM was 5.7 % (12/210). The incidence of RE was the same in male patients (2.9 %) as in female patients (2.9 %) (p=0.324). The occurrence of an RE in the left MFM was 7.3 % (3/41 patients) for male patients and 4.5 % (3/66) for female patients (p=0.398). The right MFM in male patients had an incidence of 8.1 % (3/37) and 4.5 % (3/66) for female patients (p=0.340). When the presence of an RE was compared between the left (5.6 %) and right side (5.8 %), no statistically significant differences were found (p=0.998). The frequency of bilateral three-rooted MFM was 71.43 % (5/7) and 28.57 % (2/7) were unilateral. The prevalence of RE in MFM in a southern Chilean sub-population was 5.7 %. The occurrence was bilateral in the majority of cases and no significant differences were observed by sex or side. The commonest type of RE was Type 1 (83.3 %). The use of CBCT can improve the endodontic treatment outcome.

RESUMEN: El objetivo de este estudio fue evaluar la prevalencia y morfología de radix entomolaris (RE) en el primer mo- lar mandibular (MFM) en una subpoblación del sur de Chile mediante tomografía computarizada de haz cónico (CBCT). Se analizaron doscientas diez imágenes CBCT de MFM. Para detectar la presencia de OD se estandarizó la observación y las medidas, avanzando 1 mm apical desde el suelo de la cámara pulpar hasta la zona más apical del diente. Los datos fueron analizados mediante estadística descriptiva, siendo estadísticamente significativo un valor de P < 0,05. La prevalencia de una tercera raíz en el MFM permanente fue de 5,7 % (12/210). La incidencia de ER fue la misma en pacientes masculinos (2,9 %) que en pacientes femeninas (2,9 %) (p=0,324). La aparición de un ER en el MFM izquier- do fue del 7,3 % (3/41 pacientes) para los pacientes masculinos y del 4,5 % (3/66) para las pacientes femeninas (p=0,398). El MFM derecho en pacientes masculinos tuvo una incidencia de 8,1 % (3/ 37) y 4,5 % (3/66) para pacientes femeninos (p=0,340). Cuando se comparó la presencia de un OD entre el lado izquierdo (5,6 %) y derecho (5,8 %), no se encontraron diferencias estadísticamente significativas (p=0,998). La frecuencia de MFM de tres raíces bilaterales fue 71,43 % (5/7) y 28,57 % (2/7) fueron unilaterales. La prevalencia de RE en MFM en una subpoblación del sur de Chile fue de 5,7 %. La presentación fue bilateral en la mayoría de los casos y no se observaron diferencias significativas por sexo o lado. El tipo de ER más frecuente fue el tipo 1 (83,3 %). El uso de CBCT puede mejorar el resultado del tratamiento endodóntico.

Root anatomy and canal configuration of maxillary premolars: a cone-beam computed tomography study / Anatomía de la raíz y configuración del conducto de los premolares maxilares: estudio de tomografía computarizada de haz cónico

SUMMARY: The aim of the study was to determine the number and anatomical configuration of roots and root canals of maxillary first and second premolars using cone-beam computed tomography scans. n273 CBCT scans were evaluated, obtaining a sample of 592 maxillary premolars. Root number and root canal anatomy were categorized using Ahmed´s classification. Data was analyzed using Pearson's Chi-squared test. Two roots were present on 157 first premolars, one root in 132 premolars and three roots in 17. Second premolars presented one root in 266 samples and two roots in 20; no second premolars presented three roots. Eight different configurations were found; the most frequent was 2MP B1 P1 in first premolars (51,3 %) and 1MP1 (63.6 %) in second premolars. The most frequent morphology found in maxillary premolars in Chilean population was two and three roots. The analysis of internal anatomy using CBCT revealed a highly variable distribution of root canals, generally of low to medium complexity, similar to what is found in other ethnic groups.

RESUMEN: El objetivo de este estudio fue determinar el número y la configuración de raíces y canales radiculares de primeros y segundos premolares maxilares utilizado tomografía computacional de haz cónico. 273 TCHC fueron evaluados, obtenido una muestra de 592 premolares maxilares. El número de raíces y la anatomía de los canales radiculares fueron categorizados utilizando la clasificación de Ahmed. Los datos fueron analizados con la prueba Chi- Cuadrado de Pearson. Dos raíces fueron observadas en 157 primeros presentaron una raíz en 266 muestras y dos raíces en 20; no se encontraron tres raíces en segundos premolares. Ocho diferentes configuraciones fueron encontradas; siendo la más frecuente 2MP B1 P1 en primeros premolares (51,3 %) y 1MP1 (63,6 %) en segundos premolares. La morfología radicular más frecuentemente encontrada en premolares de población Chilena fue de dos y tres raíces. El análisis de la anatomía interna usando TCHC mostró una gran variabilidad de en la distribución de los canales radiculares. Generalmente de mediana y baja complejidad como los encontrados en otros grupos etnicos.

Three Dimensional mapping of the root apex: distances between apexes and anatomical structures and external cortical plates

Abstract This study aimed to determine the mean distances between apexes of the maxillary posterior teeth and the maxillary sinus, between apexes of the mandibular posterior teeth and the mandibular canal, and between the root apexes of all teeth and the adjacent cortical plates. A total of 800 cone-beam computed tomography (CBCT) scans (400 maxillary and 400 mandibular) were obtained from patients indicated for several treatments. The proximity between apexes and anatomical structures, and the relationship between apexes and adjacent cortical plates were assessed together with the risk of over-instrumentation. Paired-sample comparisons were performed by using the paired t-test. The means were compared by ANOVA, Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner tests. a) Most of the apexes classified as A (high-risk proximity) were observed in maxillary first and second molars, in mandibular first and second molars, and in second premolars in relation to near anatomical structures. b) A predominance of class A (86.42%) was noticed in the first premolars, between apexes of maxillary teeth and adjacent cortical plates. c) The distance between apexes of mandibular teeth and buccal cortical plates showed a predominance of medium-risk proximity (B) in all the groups, except the first premolars, with the highest risk (82.22%), and the second molars, with low-risk proximity (C) to distal and mesiobuccal apexes (91.77% and 89.62%). CBCT images are important for endodontic diagnosis and treatment, since many teeth have high risk proximity to near anatomical structures and adjacent cortical plates.

Micro-CT evaluation of maxillary first molars: interorifice distances and internal anatomy of the mesiobuccal root

Abstract: This study aimed to describe the morphometric relationship of root canal orifices on the pulp floor in the presence/absence of mesiobuccal second canal (MB2) in the maxillary first molars and other aspects of its internal anatomy. Sixty-two maxillary first molars were scanned by micro-CT. The presence of the MB2 canal was verified. The distance between the center points of the MB1, MB2, distobuccal (DB), and palatal (P) canal orifices on the pulp floor were measured (MB1-MB2, MB1-DB, MB2-DB, MB1-P, and DB-P). The MB1-P to DB-P ratio was calculated. The distances between the anatomic apex and the MB1 and MB2 apical foramina were measured. The length of the band-shaped isthmus was also measured. Student's t-test was applied to verify the association between the presence of an MB2 canal, the interorifice distances, and the ratio of the MB1-P to DB-P distance (α = 5%). The MB2 canal was present in 43 roots (69.35%). Statistics showed significant differences when MB2 was present for the largest MB1-P distance (p < 0.05) and higher values for the MB1-P to DB-P ratio (p < 0.05). A band-shaped isthmus was detected in 25.8% of MB roots. The mean distance from the apical foramen to the isthmus floor ranged from 1.74 for MB1 canals to 1.42 for MB2 canals. Canal orifice distances on the pulp floor may predict the presence of MB2 canals. There was a high incidence of isthmus, accessory canals, and apical delta in the critical apical zone in MB roots of maxillary first molars.

Tratamiento regenerativo de lesión interproximal consecuente a fractura del tercio medio en diente permanente joven / Regenerative treatment of interproximal lesion following middle third fracture in a young permanent tooth

Se presenta un caso clínico de fractura radicular del tercio medio, de pieza 2.1 con desplazamiento de los cabos de fractura. Es tratado con un novedoso procedimiento terapéutico, mediante la utilización de un biomaterial de tercera generación osteoconductor, osteogénico y osteoinductor. Se obtiene la reparación del tejido conectivo interproximal y la formación de tejido calcificado (AU)

We present a clinical case of root fracture of the middle third, piece 2.1 with displacement of the fracture ends. It is treated with a novel therapeutic procedure, using a thirdgeneration osteoconductive, osteogenic and osteoinductive biomaterial. Interproximal connective tissue repair and calcified tissue formation are obtained (AU)

Accuracy of periapical and panoramic radiography for detection of root morphologies: a comparative study

Abstract: Maxillary and mandibular incisors have increased risk for severe orthodontically induced inflammatory root resorption. A patient-related risk factor is aberrant root morphology. This study aimed to assess the frequency of detection of different root morphologies in anterior teeth using dental panoramic tomography (DPT) and long cone periapical radiographs (LCPAs). A retrospective cross-sectional design was used to assess a sample of 50 consecutive pre-treatment radiographic records of patients from a specialist orthodontic practice in Adelaide, Australia. A reference guide was developed that included three previously unreported morphologies: pipette and bent, bent and pointed, bent and blunt. Two trained and calibrated assessors examined each record against the inclusion criteria, then independently assessed each anterior tooth from DPTs and LCPAs to detect the type of root morphology present. Data were analysed using the chi-square statistical test. Radiographic records for 48 patients (48 DPTs and 161 LCPAs) were eligible, with 355 and 426 teeth on DPTs and LCPAs, respectively, included for assessment. Normal root morphology (119 teeth) was commonly observed in DPTs, while bent (154 teeth) was frequently observed using LCPAs. Mandibular incisors often had normal morphology in DPTs but bent in LCPAs. Bent was the most common morphology in maxillary lateral incisors using DPT and LCPAs, although maxillary centrals were mostly normal in DPTs but pointed in LCPAs. Differences using the two image acquisition methods were highly significant (p < 0.01). Aberrant root morphologies are more easily detected in anterior teeth using LCPAs compared to DPTs.

Methodological considerations for a model of endodontic treatment in Wistar rats / Consideraciones metodológicas para el modelo de tratamiento endodóntico en ratas Wistar

ABSTRACT The use of correctly designed animal models is a fundamental step prior to clinical trials in humans. Although rats are easy to house and handle, and have molars that resemble those of humans, very few researchers use them as a model for root canal treatment, probably due to their small size and the lack of relevant data necessary to reproduce the model. Our aims were to describe the anatomic and histologic characteristics of the mandibular first molar of the Wistar rat and present a standardised model for its experimental endodontic treatment. Twenty female rats were used. The characteristics of the mesial and distal roots were described histologically and the quality of the results achieved following the treatment protocol presented herein was assessed by means of digital radiographs, micro-CT and histological sections. The age of 55 days was found to be the most adequate for performing this technique, but we consider the interval of 50 to 60 days to be suitable. Both canals are oval, although in opposite planes, and the furcating-facing walls present the minimum dentine thickness. It was essential to become familiar with these aspects in order to decide upon the most appropriate instrumentation and obturation techniques that would enable replication of this model in basic science research.

RESUMEN El uso de modelos animales correctamente diseñados es un paso fundamental previo al desarrollo de ensayos clínicos en humanos. A pesar de resultar fáciles de criar y manipular y de poseer molares que se asemejan a los humanos, muy pocos grupos utilizan a la rata como modelo experimental para el tratamiento endodóntico probablemente debido a su pequeño tamaño y a la escasa información disponible para poder aplicar los modelos existentes. Nuestros objetivos fueron describir las características anatómicas e histológicas del primer molar inferior de la rata Wistar y presentar un modelo estandarizado para el tratamiento endodóntico experimental de esta pieza. Se utilizaron 20 ratas hembra. Las características de las raíces mesial y distal fueron descritas histológicamente y los resultados obtenidos fueron evaluados mediante radiografías digitales, microCTy cortes histológicos. La edad de 55 días demostró ser la más adecuada para ejecutar la técnica, pero consideramos que el intervalo de 50 a 60 días puede resultar apropiado. Se observó que ambos canales presentan una morfología oval, aunque en direcciones opuestas, y que las paredes furcales resultaron ser las que presentan el menor espesor de dentina. Familiarizarse con estos aspectos de la anatomía e histología del molar de la rata resultó fundamental para decidir sobre las técnicas de preparación y obturación más apropiadas que permitieran la replicación de este modelo en el campo de las ciencias básicas.

Accuracy of cone-beam computed tomography in measuring the thickness of radicular dentin

Abstract The purpose of this study was to evaluate the accuracy of Cone-Beam Computed Tomography (CBCT) in measuring radicular dentin thickness focused on intraradicular post placement planning treatment. Ten single-rooted human premolars were selected. The teeth were divided into three segments (cervical, middle and apical). The coronal face of the apical and middle sections was selected for the dentin thickness assessment; which was measured from the external root surface to the root canal wall, on the buccal, lingual, mesial, and distal surfaces of each tooth. In situ anatomical measurement was the reference standard, and the corresponding axial CBCT imaging were evaluated by the i-CAT software. The one-way ANOVA test and the Bonferroni post hoc test were applied to compare the groups (p>0.05). CBCT imaging measurements (p=0.003) overestimated the radicular dentin thickness compared to the reference standard. Descriptive analysis showed that the greatest difference between the reference standard and the tomographic measurement means were 0.20 mm. One-way ANOVA test found the statistical significant difference among group's measurements. Bonferroni correction demonstrated statistically significant difference only related lingual surface for the CBCT imaging measurements. CBCT imaging measurements overestimated the radicular dentin thickness. However, the measurement difference was clinically acceptable.

Resumo O objetivo deste estudo foi avaliar a precisão da Tomografia Computadorizada de Feixe Cônico (TCFC) na mensuração da espessura da dentina radicular no planejamento de tratamento envolvendo a cimentação de pinos intrarradiculares. Dez pré-molares humanos unirradiculares foram selecionados. Os dentes foram divididos em três segmentos (cervical, médio e apical). A face coronal dos terços apical e médio foi selecionada para a avaliação da espessura da dentina; que foi medida a partir da superfície externa da raiz até a parede do canal radicular, nas superfícies vestibular, lingual, mesial e distal de cada dente. A medida anatômica in situ foi o padrão de referência, e a imagem de TCFC axial correspondente foi avaliada pelo software i-CAT. O teste de 1-fator ANOVA e o teste post hoc de Bonferroni foram aplicados para comparar os grupos (p>0,05). As medidas de imagem da TCFC (p=0,003) superestimaram a espessura da dentina radicular em comparação a referência padrão. A análise descritiva mostrou que a maior diferença entre a referência padrão e a medida tomográfica foi de 0,20 mm. O teste ANOVA encontrou a diferença de significância estatística entre as medidas do grupo. A correção de Bonferroni demonstrou diferença estatisticamente significante apenas relacionada às medidas de imagem da TCFC. A medida de imagem da TCFC superestimou a espessura da dentina radicular. No entanto, a diferença de medição foi clinicamente aceitável.

Limitation of diagnostic value of cone-beam CT in detecting apical root isthmuses

Abstract Isthmuses are reported as common anatomic complexities in teeth often associated with failures in endodontic treatment. They should be considered before starting treatment and a preoperative computed tomography scan (CT) may demonstrate these complexities. Objective To assess the diagnostic value of the highest resolution settings of a cone-beam CT (CBCT) system in identifying and measuring apical isthmuses, using micro-CT as reference. Methodology After micro-CT scanning, 40 humans' lower first molars with isthmuses in the apical-3 mm of mesial roots were scanned by the highest resolution settings of the New Generation i-Cat ® CBCT equipment. Two blinded observers recorded the detection of isthmuses in CBCT scans. The lengths of isthmuses were compared between micro-CT and CBCT to assess the diagnostic value of CBCT. Quantitative data for sensitivity were represented as percentages (95% confidence interval). The Bland-Altman method was used to assess differences between gold standard lengths (micro-CT) and CBCT lengths. Results BCT demonstrated 30 positive findings, representing sensitivity for isthmus identification of 75% (95% CI=0.4114-1.1364). Differences between the lengths in micro-CT (1.99±0.40 mm) and CBCT (1.53±0.41 mm) were significant (p<0.0001). Conclusion The CBCT device used presented limited diagnostic value in the identification and measurement of apical isthmuses in the mesial roots of lower molars. In some cases, the actual anatomy of the apical root canal may not be completely delineated in this type of CBCT system, even using the highest resolution settings.

Penetration degree of sealer in artificial lateral canal after passive ultrasonic irrigation with EDTA for different times / Grau de penetração do cimento obturador em canais laterais simulados após ativação ultrassonica passiva do EDTA em diferentes tempos

The aim of this study was to evaluate the degree of penetration of obturation cement in artificial lateral canals after Passive Ultrasonic Irrigation (PUI) with ethylenediaminetetraacetic acid (EDTA) for different times. Fifty upper molar palatine roots were used, in which two artificial lateral canals were made at distances of 7 and 3 millimeters from the root apex. After instrumentation and drying the canal, the final toilet stage was performed on five groups (n = 10), as follows: G1 - EDTA 17% + PUI for 10 seconds; G2 - EDTA 17% + PUI for 20 seconds; G3 - EDTA 17% + PUI for 30 seconds; G4 - EDTA 17% + PUI for 60 seconds; G5 - EDTA 17% + activation by instrument R50 for 5 minutes (Control). The canals were sealed by the single cone technique, and after 72 hours, sectioned in two planes transverse to the artificial canal, to see the degree of penetration of the sealing cement. In the radiographic analysis, there was no statistical difference (p> 0.05) between groups in the two artificial lateral canals. However, PUI of EDTA for 60 seconds produced a significant difference in the degree of penetration of the sealing cement (p <0.05) at 7 mm from the apex. Therefore, PUI with EDTA for 60 seconds promoted a higher degree of penetration of the obturator cement in the artificial lateral canal.

O objetivo deste trabalho foi avaliar o grau de penetração do cimento obturador em canais laterais artficiais, após Irrigação Ultrassonica Passiva (IUP) do ácido etilenodiaminotetracético (EDTA), em diferentes tempos. Foram utilizadas 50 raízes palatinas de molares superiores, e em seguida confeccionados dois canais laterais artificiais a 7 e 3 milímetros do ápice radicular. Após a instrumentação e secagem dos canais, foi iniciada a etapa de toillet final, de acordo com os seguintes grupos (n=10): G1- EDTA 17%+IUP durante 10 segundos; G2 - EDTA 17%+IUP durante 20 segundos; G3 - EDTA 17%+IUP durante 30 segundos; G4- EDTA 17%+IUP durante 60 segundos; G5- EDTA 17%+ativação pelo instrumento R50 durante 5 minutos (Controle). Os canais foram obturados pela técnica do cone único, e após 72 horas, seccionados em dois planos transversais dos canais artificiais, para se visualizar o grau de penetração do cimento obturador. Na análise radiográfica, não houve diferença estatística (p>0,05) entre os grupos, nos dois canais laterais artificiais. Entretanto, a IUP do EDTA por 60 segundos conseguiu um obter resultado significativo, sobre o grau de penetração do cimento obturador (p<0,05) a 7 milímetros do ápice. Portanto, a IUP do EDTA no tempo de 60 segundos promoveu maior grau de penetração do cimento obturador nos canais laterais artifciais.

Association between radiographic classification and surgical technique in extractions of third lower molars / Associação entre classificação radiográfica e técnica cirúrgica nas exodontias de terceiros molares inferiores

Introduction: establish an association between the radiographic classification and the surgical technique related to the lower third molars. Materials and method: a retrospective study was carried out, with the descriptive analysis of the data. The sample consisted of 100 patients (n = 100) from the spontaneous demand who sought out the Dental Clinic of UFC (Ceará's Federal University) ­ Campus Sobral, between december 2017 to july 2018, and who followed the inclusion criteria: patient with panoramic radiography, free of active periodontal disease and tooth with at least two thirds of root formation; and as exclusion criteria: patients with associated bone pathologies, teeth with less than two thirds of root formation and patients who did not wish to participate in the study. Results: patients included in the study were from 18 to 25 years of age, most of them male, with complaints of pain. Using the radiographic classification of Pell & Gregory, the most found positions were 1A (35%), 2B (28%) and 2A (17%). The most prevalent surgical techniques were the open ones. Could be done the extraction by closed surgical technique (forceps or lever) (n = 27), with flap preparation plus osteotomy (OST) (n = 25) and flap plus osteotomy plus odontostomy (ODS) (n = 48). Conclusion: teeth with radiographic classification, grade of inclusion and different preoperative plans had the same protocol (flap + OST + ODS) in the surgical act. It is evident that radiographic classification stills an effective method to aid in operative planning, but it can be complemented by other diagnostic standards, such as a specific classification of the root anatomy. (AU)

Objetivo: realizar uma associação entre a classificação radiográfica e a técnica cirúrgica relacionada aos terceiros molares inferiores. Materiais e método: foi realizado um estudo retrospectivo, com a análise descritiva dos dados. A amostra foi constituída de 100 pacientes (n = 100), provenientes de demanda espontânea, que procuraram o ambulatório de Odontologia da Universidade Federal do Ceará (UFC) ­ Campus Sobral, no período de dezembro de 2017 a julho de 2018, e que seguiram os seguintes critérios de inclusão: presença de radiografia panorâmica, ausência de doença periodontal ativa e dentes com no mínimo dois terços de formação radicular. Já os critérios de exclusão foram: pacientes com patologias ósseas associadas aos terceiros molares inferiores, dentes com menos de dois terços de formação radicular e pacientes que não desejassem participar do estudo. Resultados: os pacientes incluídos no estudo tinham idades entre 18 e 25 anos, a maioria do sexo masculino, com queixas álgicas. Em relação à classificação de Pell & Gregory, as posições mais encontradas foram 1A (35%), 2B (28%) e 2A (17%). As técnicas cirúrgicas mais prevalentes foram as abertas (73%). Em relação às técnicas cirúrgicas, foram encontradas: técnica cirúrgica fechada (fórceps ou alavanca) (n = 27), com confecção de retalho mais osteotomia (OST) (n = 25) e por retalho mais osteotomia e odontossecção (ODS) (n = 48). Conclusão: é evidente que a classificação radiográfica ainda é um método eficaz para auxiliar no planejamento operatório, mas pode ser complementada por outros padrões de diagnóstico, como uma classificação específica da anatomia radicular. (AU)

Relación entre el piso del seno maxilar y las raíces de las piezas posteriores superiores, mediante tomografía computada / Relationship between maxillary sinus floor and the posterior upper teeth roots, by means of computed tomography

Objetivo: El objetivo de este estudio fue evaluar la frecuencia con que las raíces de premolares y molares superiores se encuentran dentro del seno maxilar. Conocer la relación entre dichas estructuras es importante para planificar los procedimientos endodónticos y quirúrgicos a ser realizados en esa región. Materiales y métodos: Se realizó el análisis cualitativo dinámico de 82 tomografías computadas de haz cónico (CBCT) unilaterales, analizándose 738 raíces correspondientes a premolares y molares de una sola hemiarcada superior. Se utilizó sala con iluminación controlada y la observación fue realizada por un solo examinador. El criterio de inclusión requería que la cortical inferior del seno maxilar debía ser visible para poder establecer la relación. Se utilizaron los tres planos tomográficos de visualización, permitiendo ajustes de brillo y contraste. La escala de clasificación de cada raíz consideró su relación como: dentro o fuera del seno maxilar. Los datos obtenidos fueron sometidos a las pruebas de Chi-cuadrado y Test Exacto de Fisher. Resultados: el primer premolar superior mostró una proyección hacia el interior del seno maxilar significativamente menor que las otras piezas dentarias posteriores (p>0.05), observándose su raíz vestibular sin proyección. La raíz palatina del primer premolar superior mostró la mayor incidencia dentro del seno maxilar, con un 39,02% del total de las raíces analizadas (p<0,05). El segundo molar superior mostró considerable proximidad con el seno maxilar, pero con menor incidencia con relación a la raíz palatina del primer molar. Conclusión: los procedimientos endodónticos o quirúrgicos a realizarse en cercanía al seno maxilar deben considerar siempre la relación raíz/seno, para evitar maniobras que lo invadan. La raíz palatina del primer molar superior mostró la mayor incidencia dentro del seno maxilar, con un 39,02% (AU)

A comparison of the sealing abilities between Biodentine and MTA as root-end filling materials and their effects on bone healing in dogs after periradicular surgery

ABSTRACT Objectives: To compare the sealing ability and biocompatibility of Biodentine with mineral trioxide aggregate (MTA) when used as root-end filling materials. Methodology: The Cell Counting Kit-8 (CCK-8) assay was used to compare the cytotoxicity of MTA and Biodentine. Twenty-one extracted teeth with a single canal were immersed in an acidic silver nitrate solution after root-end filling. Then, the volume and depth of silver nitrate that infiltrated the apical portion of the teeth were analyzed using micro-computed tomography (micro-CT). Seventy-two roots from 3 female beagle dogs were randomly distributed into 3 groups and apical surgery was performed. After six months, the volume of the bone defect surrounding these roots was analyzed using micro-CT. Results: Based on the results of the CCK-8 assay, MTA and Biodentine did not show statistically significant differences in cytotoxicity (P>0.05). The volume and the depth of the infiltrated nitrate solution were greater in the MTA group than in the Biodentine group (P<0.05). The volume of the bone defect was larger in the MTA group than in the Biodentine group. However, the difference was not significant (P>0.05). The volumes of the bone defects in the MTA and Biodentine groups were smaller than the group without any filling materials (P<0.05). Conclusions: MTA and Biodentine exhibited comparable cellular biocompatibility. Biodentine showed a superior sealing ability to MTA in root-end filling. Both Biodentine and MTA promoted periradicular bone healing in beagle dog periradicular surgery models.

Three-dimensional assessment of external apical root resorption after maxillary posterior teeth intrusion with miniscrews in anterior open bite patients

ABSTRACT Objective: The objective of this study was to assess the external apical root resorption (EARR) of the maxillary posterior teeth after intrusion with miniscrews. Methods: Fifteen patients (13 females and 2 males) with age ranging from 14.5 to 22 years (mean 18.1 ±2.03 years) were selected to participate in this study. All patients presented with anterior open bite of 3 mm or more. An intrusion force of 300 g was applied on each side to intrude the maxillary posterior teeth. Cone beam computed tomography (CBCT) scans were taken pretreatment and post-intrusion and were analyzed to evaluate the EARR. Results: The maxillary posterior teeth were intruded in average 2.79 ± 0.46 mm (p< 0.001) in 5.1 ± 1.3 months, and all examined roots showed statistically significant EARR (p< 0.05) with an average of 0.55 mm, except the distobuccal root of the left first permanent molars and both the palatal and buccal roots of left first premolars, which showed no statistically significant changes. Conclusions: The evaluated teeth presented statistically significant EARR, but clinically, due to the small magnitude, it was not considered significant. Moreover, the CBCT provided a good visualization of all roots in all three planes, and it was effective in detecting minimal degrees of EARR.

RESUMO Objetivo: o objetivo desse estudo foi verificar a existência de reabsorção radicular apical externa (RRAE) em dentes posterossuperiores após intrusão ancorada em mini-implantes. Métodos: quinze pacientes (13 mulheres e 2 homens) com a idade variando entre 14,5 e 22 anos (média de 18,1 ± 2,03 anos) foram selecionados para participar desse estudo. Todos os pacientes possuíam mordida aberta anterior de 3mm ou mais. Uma força de 300 gramas foi aplicada em cada lado para intruir os dentes posterossuperiores. Tomografias computadorizadas de feixe cônico (TCFC), adquiridas antes do tratamento e após a intrusão, foram comparadas para se avaliar a RRAE. Resultados: os dentes posterossuperiores foram intruídos em média 2,70 ± 0,46 mm (p< 0,001) em 5,1 ± 1,3 meses, e todas as raízes examinadas mostraram RRAE estatisticamente significativa (p< 0,05), com média de 0,55 mm, exceto pela raiz distovestibular dos primeiros molares permanentes esquerdos, e pelas raízes palatina e vestibular dos primeiros pré-molares esquerdos, que não apresentaram mudanças estatisticamente significativas. Conclusões: os dentes avaliados apresentaram RRAE estatisticamente significativa, a qual, porém, não foi considerada clinicamente significativa, devido à sua reduzida magnitude. Além disso, a TCFC possibilitou uma boa visualização de todas as raízes nos três planos espaciais, e foi eficaz para detecção de níveis mínimos de RRAE.

Distancia entre la raíz palatina del primer molar superior permanente y el piso del seno maxilar, obtenida mediante tomografía computarizada cone beam / Distance between the palatal root of the first permanent upper molar to the floor of the maxillary sinus, obtained by cone beam computed tomography

El conocimiento de las relaciones anatómicas entre el piso del seno maxilar y los ápices de dientes maxilares posteriores, es muy importante al planificar una terapia endodóntica o cirugías en molares maxilares. Este estudio tiene por objetivo, establecer la distancia existente entre el ápice de la raíz palatina del primer molar superior y el piso del seno maxilar, obtenida de una muestra de 61 tomografías volumétricas Cone beam. Se realizó un estudio observacional transversal, donde se procedió a medir la distancia entre el ápice de la raíz palatina del primer molar superior y el piso del seno maxilar en 61 tomografías volumétricas Cone Beam, obteniendo medidas de un total de 107 raíces palatinas de molares maxilares. Las imágenes fueron almacenadas en formato DICOM y analizadas con el software Sky View Dental Plan en un computador HP Compaq LA1951g Z600 y en su análisis estadístico se utilizó el Programa Stata 11.0. El promedio de distancia registrado entre el ápice de la raíz palatina del primer molar superior y el piso del seno maxilar fue de 1,2 mm. La mayor distancia fue de 12,5 mm y la menor de 0 mm. La medida de 0 mm se presentó en 48 casos y alcanzó al 44,9 % de la muestra. Es frecuente que los ápices radiculares se encuentren dentro del seno maxilar, condición que debe ser de conocimiento clínico, con el objetivo de prevenir al máximo accidentes y complicaciones en las terapias endodónticas.

The knowledge of the anatomical relationships between the floor of the maxillary sinus and the apices of the posterior maxillary teeth is very important when planning an endodontic therapy or surgeries in the area. The objective of this study is to establish the distance between the apex of the palatal root of the first maxillary molar and the floor of the maxillary sinus, in a sample of 61 cone-beam computed tomography. A crosssectional observational study was carried out. We proceeded to measure the distance between the apex of the palatal root of the first upper molar and the floor of the maxillary sinus in 61 conebeam computed tomography, obtaining measurements of a total of 107 first maxillary molar palatal roots. The images were stored in DICOM format and analyzed with the Sky View software and the Stata 11.0. for statistical analysis. The average distance recorded between the apex of the palatal root of the first upper molar and the floor of the maxillary sinus was 1.2 mm. The greatest distance was 12.5 mm and the smallest was 0 mm. The measurement of 0 mm was presented in 48 cases and reached 44.9 % of the sample. It is common for radicular apices to be located within the maxillary sinus. The clinician must know this condition to prevent accidents and complications in the endodontic therapies as much as possible.

Сross-sectional anatomic study of direct positional relationships between mandibular canal and roots of posterior teeth using cone beam computed tomography

Objectives: to establish the frequency of the various types of direct contacts of the root apices with the wall of the mandibular canal and to determine gender differences in number of such contacts in a selected belarusian population using cone beam computed tomography. methodology: one hundred and two cone beam computed tomography scans were analyzed to classify the types of contact and three-dimensional relationship between the mandibular teeth and the mandibular canal. results: the direct contact between the teeth and the mandibular canal was observed in 63.7 percent of patients. overall 300 roots of 189 teeth were in direct contact with the mandibular canal: 9.3 percent were second premolars, 14.7 percent were first molars, 33.8 percent were second molars and 50.0 percent were third molars. there were no statistically significant differences in the number of teeth with direct contact with the mandibular canal between males and females. conclusion: the direct contact of the root apices with the mandibular canal was most often found in the second and third molars. the root apices of the third molars had the greatest variability of location relatively to the mandibular canal.