Influence of root shape on canal complexity at the mandibular molar apical surgical resection level: A micro-CT study.

OBJECTIVES: This study aimed to investigate the relationship between the aspect ratios of mandibular molar roots at the apical 3-mm level and their root canal complexity. DESIGN: This study used micro-CT imaging to analyze 163 two-rooted mandibular molars. The aspect ratios of the roots at the apical 3-mm level were categorized as "< 2.75" or "≥ 2.75" (mesial) and "< 1.75" or "≥ 1.75" (distal). A two-dimensional (2D) analysis focused on four apical axial cross-section levels to determine the presence of main and accessory canals and isthmus. Additionally, a three-dimensional (3D) assessment of the apical 4-mm of both roots examined main and accessory canals, apical foramina, apical deltas, and middle mesial canals. RESULTS: Mesial roots with aspect ratios ≥ 2.75 showed a higher number of main canals at all levels compared to those with aspect ratios < 2.75 at the 3-mm level. Additionally, the ≥ 2.75 group exhibited more accessory canals and a higher average number of accessory canals. The 3D assessment confirmed significantly more accessory canals and apical foramina in the ≥ 2.75 group. The prevalence of roots with apical deltas was nearly double in the ≥ 2.75 group, and middle mesial canals were exclusively found in this group. In the distal root, the ≥ 1.75 group showed a significantly higher number of main canals at all axial levels. No significant differences were observed between groups in terms of accessory canals, apical foramina, or deltas. CONCLUSIONS: A higher root aspect ratio is related to higher anatomical complexity.

The clinical outcomes of vital intact teeth close to large cystic lesions of endodontic origin: A prospective clinical study.

AIM: To evaluate the indication of the endodontic treatment for vital intact teeth with the root apex involved in large radicular cystic lesions of endodontic origin. METHODOLOGY: This prospective cohort study enrolled healthy participants with radicular cysts of endodontic origin and with the root apex of vital intact teeth involved in the bone defect, as determined by cone beam computed tomography (CBCT). Thirty-two sound vital teeth were analysed by thermal (TPT) and electric pulp tests (EPT) before surgery (T0) and 1 week (T1), 2 weeks (T2), 3 months (T3) and 6 months (T4) post-surgery. Student's t-test (p < .05) was used to compare the EPT values at baseline and T4. anova (p < .05) was used to analyse the EPT variations for all maxillary and mandibular teeth. McNemar test (p < .05) was used to compare the results according to variation in EPT values gathering by variation, no variation and no response. RESULTS: At T1, 75 and 65.7% of teeth responded positively whilst 25 and 34.3% did not respond to EPT and TPT, respectively. The variation of the EPT values between T0 and T1 was observed for 50.0% of teeth, whilst no variation was noticed in 25.0% of teeth. At T4, 90.6 and 87.5% of teeth responded positively whilst 9.4 and 12.5% did not respond to EPT and TPT, respectively. At T4, variation of the EPT values between T0 and T4 was observed for 28.1%, whilst no variation was noticed in 62.5% of teeth. There were no statistical differences in EPT results between T0 and T4 (p > .05), but significant differences were observed for EPT values between T1 and T4 (p < .05), and between mandibular and maxillary teeth. The pulp sensibility of maxillary teeth worsened after surgery, before reverting progressively to T0 values, whilst no statistically significant differences were observed for mandibular teeth at the different time points. CONCLUSIONS: These data support the inconsistence of the prophylactic endodontic treatment in healthy vital teeth with apex involvement in large cystic lesions of endodontic origin. Post-surgery follow-up with TPT and EPT is recommended to assess pulp status.

Relación entre el seno maxilar y ápices de dientes postero- superiores con tomografía computarizada de haz cónico / Relationship between the maxillary sinus and apices of posterior-superior teeth using cone beam computed tomography

El conocimiento de la relación entre el seno maxilar y los ápices de los dientes posterosuperiores es fundamental para evitar complicaciones frente a distintos tratamientos. Estudio descriptivo de corte transversal, con muestra por conveniencia de 383 imágenes de raíces de dientes posterosuperiores obtenidas por medio de tomografía computarizada de haz cónico (TCHC) de un centro radiológico en Viña del Mar, Chile. Cada raíz fue clasificada según su relación vertical con el seno en 4 categorías (0: ápice no se encuentra en contacto con contorno inferior del seno; 1: ápice en contacto con seno; 2: ápice lateralmente al seno; 3: ápice se protruye en seno). Además se midió su distancia en mm. Los datos fueron analizados con estadística descriptivas. El diente más lejano al seno maxilar fue el primer premolar superior (4.2 mm), seguido por el segundo premolar superior (1 mm). En el primer molar superior la raíz más lejana fue la mesio-vestibular (MV) 1mm, seguida por la raíz disto-vestibular (DV) 0.6mm y la raíz palatina (P) -1mm. En el segundo molar superior la raíz más lejana fue P 0.4mm, luego la DV 0.3mm, y MV -0,11mm. En cuanto a las categorías, se observó que la mayoría de las raíces se encuentran alejadas del seno siendo la raíz P del primer molar superior y la raíz MV del segundo molar superior las que se encuentran mayormente protruidas (42 % y 26 % respectivamente). El primer premolar es el diente posterosuperior que se encuentra más alejado del seno maxilar y a medida que se avanza hacia posterior hay tendencia a disminuir la distancia entre los ápices y el seno maxilar.

SUMMARY: Knowledge of the relationship between the maxillary sinus and the apices of the upper posterior teeth is crucial to avoid complications when considering different treatments. A descriptive cross-sectional study was carried out, with a convenience sample of 383 images of upper posterior teeth roots, obtained by means of cone beam computed tomography (CBCT) from a radiological center in Viña del Mar, Chile. Each root was classified according to its vertical relationship with the sinus into 4 categories (0: apex is not in contact with the lower contour of the sinus; 1: apex is in contact with the sinus; 2: apex laterally to the sinus; 3: apex protrudes in sinus). In addition, its distance was measured in mm. The data were analyzed with descriptive statistics. The tooth farthest from the maxillary sinus was the maxillary first premolar (4.2 mm), followed by the maxillary second premolar (1 mm). In the upper first molar, the most distant root was the mesiobuccal (MV) 1mm, followed by the distobuccal root (DV) 0.6mm and the palatal root (P) -1mm. In the upper second molar, the furthest root was P 0.4mm, then DV 0.3mm, and MV -0.11mm. In reference to the categories, it was observed that most of the roots are far from the sinus, with the P root of the first upper molar and the MV root of the second upper molar being the most protruding (42 % and 26 % respectively). The first premolar is the posterior maxillary tooth that is furthest from the maxillary sinus and as one advances posteriorly there is a tendency to decrease the distance between the apices and the maxillary sinus.

Prevalence of Short Root Anomaly in a Group of Puerto Ricans.

OBJECTIVE: To estimate the prevalence of short root anomaly (SRA) in a group of Puerto Ricans at the Advanced Education Program in Orthodontics of the University of Puerto Rico. METHODS: A cross-sectional study was conducted with digital panoramic x-rays of 203 patients (112 females and 91 males; mean age: 17 years) in Puerto Rico. Utilizing the modified Lind's method, 406 maxillary right and left central incisors (1) were measured and evaluated for SRA. Root and crown length and R/C ratio were compared by sex and side. Linear regression was used to evaluate the associations between the R/C ratio and age, sex, and side (right/left). All the statistical analyses were evaluated using significance level of .05 (2). RESULTS: The prevalence of SRA was 0.49%. The average root and crown lengths for the maxillary right and left central incisors were 19.47 and 10.28 mm, respectively. Sex was associated with root and crown length, not with the R/C ratio. No differences were observed in the R/C ratio by the side. There were no significant associations between age, sex, and side and R/C ratio in the multivariate analysis. CONCLUSION: The prevalence of SRA in our population is lower than any reported in the literature. The R/C ratio in our Hispanic population was the highest compared with those of other ethnicities. Neither the sex nor the side of the incisor was associated with the R/C ratio. These findings are contrary to those of prior reports stating that males have higher R/C ratios than females.

Mineral trioxide aggregate apexification: a 20-year case review.

Apexification strategies in traumatised non-vital immature permanent teeth can promote root-end closure and continued root development. However, traumatic injuries may compromise the integrity of generative cells of the apical papilla responsible for root maturation. This report describes the long-term treatment outcome of mineral trioxide aggregate (MTA) apexification managed with late-term surgical intervention. A seven-year-old male reported with swelling and suppuration associated with a traumatised maxillary left central incisor (#21). After palliative treatment and MTA apexification procedures, the incisor demonstrated normal function during a 14.5-year period with radiographic evidence of atypical radicular elongation. Seventeen years after initial treatment, the patient presented with mid-plate buccal swelling and surgical treatment was completed involving root resection, biopsy of a spherical mineralised tissue specimen and placement of MTA root-end filling. Periapical healing and normal tooth function was evident at the 20-year review.

Accuracy of Root ZXII, E-PEX and FIND apex locators in teeth with vital pulp: an in vivo study

Abstract: This research evaluated, in vivo, the accuracy of three electronic apex locators - EALs (Root ZXII, E-PEX and FIND) in teeth with vital pulp submitted to biopulpectomy, preserving the periodontal stump. For this study, 90 single-rooted teeth with extraction indication were selected. After positive pulpal cold sensitivity test, pulp chamber access was performed. The cervical and middle thirds of root canals were instrumented with Reciproc R25, and the K#15 file was used as a standard instrument to determine working length, forming 2 groups: Constriction (insertion of the instrument until the apical constriction limit) and Foramen (insertion of the instrument until the foramen and then repositioning at constriction, without removing the file from the canal). The hand file was stabilized with a light-cured flow resin. After extraction, the samples were analyzed through microCT SkyScan 1272, with CTAN software, which evaluated the proximity between the tip of the file to the apical constriction, providing data for comparative analysis using Kruskal-Wallis and Dunn tests (p<0.05). There was a statistically significant difference in the abilities of the EALs to detect the apical constriction after reaching the foramen with Root ZX II showing higher accuracy (89%). However, there was no difference in the accuracy of the three EALs in detecting the apical constriction without reaching the foramen. Based on the present results, we conclude that EALs may show accurate measures in detecting apical constriction and foramen, even without damaging the periodontal stump in biopulpectomy.

Effect of 2 Heat-treated Nickel-Titanium Files on Enlargement and Deformation of the Apical Foramen in Curved Canals: A Scanning Electronic Microscopic Study.

INTRODUCTION: The aim of this study was to evaluate under scanning electronic microscopy the enlargement and deformation of the apical foramen of curved mesiobuccal roots with both reciprocating and rotary single-file systems made of a newly heat-treated alloy through the use of Reciproc Blue (REC Blue; VDW, Munich, Germany) and XP-endo Shaper (XPS; FKG Dentaire, La Chaux-de-Fonds, Switzerland). METHODS: Forty mesiobuccal roots of mandibular and maxillary molars presenting a curvature ranging from 20°-40° were used in this study. The apical foramens were initially scanned with a scanning electronic microscope under 200× magnification. Roots were divided into 2 groups (n = 20): the REC Blue group instrumented with the REC Blue system and the XPS group instrumented with the XPS system. Both groups were instrumented at the foramen. The apical foramens were scanned after root canal preparation. The area, circularity, and ratio of the Feret diameters were calculated from each image. The Kolmogorov-Smirnov, Mann-Whitney, and Wilcoxon tests were used for statistical analysis (P ≤ .05). RESULTS: The area of the foramen increased significantly after canal shaping with REC Blue and XPS. The variation of the area was significantly greater with XPS. However, there were no significant differences in circularity and the ratio of the Feret diameters with both instruments. CONCLUSIONS: No transportation was found when using REC Blue and XPS. The newly heat-treated nickel-titanium alloy did not promote deformation of the apical foramen in curved canals.

Micro-computed tomographic analysis of apical foramen enlargement of mature teeth: a cadaveric study / Análisis mediante micro-CT del ensanchamiento del foramen apical de dientes maduros: un estudio cadavérico

Revitalization procedures have been extensively studied during the last decade and offers several advantages over root canal treatment, such as the recovery of the natural immune system. Mature teeth have a small apical foramen diameter (AFD), which could impair the ingrowth of tissue into the root canal. We analysed three methods for apical foramen enlargement by instrumentation in in situ human teeth and evaluated the damage over hard tissues produced by the techniques. Tooth length (TL), defined as the length from the most coronal part of the crown to the point at which the file abandons the root canal, was calculated. Forty-four in situ teeth were randomized: Group I: instrumentation 0.5 mm coronal to TL; Group II: at TL level; Group III: 0.5 mm beyond TL. Teeth were instrumented up to K-file #80. The mandibles were scanned in a micro-CT device before and after treatment. Group I: Only 20 % of teeth presented an enlarged AFD, with augmentation of 0.09 mm. No damage to hard tissues was observed. Group II: 71.4 % of the teeth presented an enlarged AFD with augmentation of 0.42 mm. 35.7 % presented damage to periapical tissues. Group III: 86.7 % presented an enlarged AFD with augmentation of 0.43 mm. 46.7 % presented damage to periapical tissues. All groups presented similar prevalence of teeth with dentine thickness less than 1mm. All mandibular incisors presented areas of thickness less than 1mm. Instrumentation 0.5 mm beyond TL is the most effective technique.

La revitalización de dientes necróticos ha sido ampliamente estudiada durante la última década y ofrece varias ventajas sobre la endodoncia convencional, tal como la recuperación del sistema inmunitario natural del diente. Los dientes maduros tienen un diámetro de foramen apical (FA) pequeño, lo que podría afectar el crecimiento de tejido en el conducto. Se evaluaron tres métodos para la ampliación del foramen apical en dientes humanos in situ y se evaluó el daño sobre los tejidos duros producidos por las técnicas. Mediante radiografía periapical se calculó la longitud del diente (TL), definida como la longitud desde la parte más coronal de la corona hasta el punto en que la lima abandonó el conducto radicular. En el estudio fueron aleatorizados 44 dientes in situ: Grupo I: instrumentación 0,5 mm coronal a TL; Grupo II: a nivel TL; Grupo III: 0,5 mm más allá de TL. Los dientes fueron instrumentados hasta la lima K #80. Las mandíbulas se escanearon en un dispositivo de microCT antes y después del tratamiento. Grupo I: solo el 20 % de los dientes presentaron un diámetro de FA ensanchado, con un aumento de 0,09 mm. No se observó daño a los tejidos duros. Grupo II: el 71,4 % de los dientes presentaban un FA ensanchado con un aumento de 0,42 mm. El 35,7 % presentó daño a los tejidos periapicales. Grupo III: el 86,7 % presentó un FA ensanchado con un aumento de 0,43 mm. El 46,7 % presentó daño a los tejidos periapicales. Todos los grupos presentaron una prevalencia similar de dientes con un espesor de dentina inferior a 1mm. Todos los incisivos mandibulares presentaban áreas de grosor inferior a 1mm. La instrumentación 0,5 mm más allá de TL es la técnica más efectiva, aunque se debe tener especial consideración en aspectos como el debilitamiento de la estructura dentaria.

Estudio de la precisión de un localizador de ápice electrónico en dientes monorradiculares / Assessment the accuracy of electronic apex locater in single canal teeth

Introducción: La correcta determinación de la longitud de trabajo es uno de los principales factores determinantes para el éxito de los tratamientos endodónticos. Objetivo: valorar si es precisa la determinación de la longitud de trabajo de un localizador de ápice electrónico en dientes monorradiculares. Métodos: se realizó un estudio experimental exploratorio in vivo, donde se determinó la longitud de trabajo en 141 conductos monorradiculares en pacientes con indicación de exodoncia. Se determinó la longitud de trabajo con un localizador de ápice electrónico iPex II(NSK). Cuando el localizador marcó que la lima se encontraba en el ápice, sin retirar el instrumento del conducto se procedió a fijarla. Se realizó la extracción con precaución y, posteriormente, se desgastó una pared proximal del tercio apical hasta que se pudo observar la lima en el interior del conducto, con auxilio de una lupa. La longitud de trabajo fue aceptable cuando el localizador determinó que estaba entre 0,5-1,5 mm del límite cemento-dentina-conducto; corto cuando estaba a más de 1,5 mm y largo cuando se observó que sobrepasaba el límite cemento-dentina-conducto. Resultados: fue aceptable la precisión en 135 (95,7 por ciento) mediciones y solo 13 (9,2 por ciento) conductos tuvieron inestabilidad, con una relación existente entre la precisión y la inestabilidad de las mediciones. Se observó que 88 (62,4 por ciento) conductos con secreciones obtuvieron un aceptable en la determinación de la longitud de trabajo, mientras que solo 3 (2,1 por ciento) conductos con secreciones tuvieron mediciones cortas. La presencia de secreciones no fue significativa para evaluar la precisión. Conclusiones: Las mediciones de las longitudes de trabajo empleando el localizador estudiado fueron mayormente de precisión aceptable y no inestables. Del mismo modo, la presencia de secreciones en el interior de los conductos radiculares no afectó significativamente la precisión del localizador en cuestión(AU)

Introduction: The correct determination of working length is one of the main determining factors for the success of endodontic treatments. Objective: to assess the accuracy when determining the working length of an electronic apex locator. Objective: To assess the accuracy of the determination of the working length of an electronic apex locator in monoradicular teeth. Material and methods: An exploratory experimental study was carried out in vivo where the working length was taken in 141 monoradicular root canals of patients with indication of extraction. Working length was determined using iPex II electronic apex locator (NSK). When the locator marked that the file was at the apex, without removing the instrument from the duct, it was fixed. The extraction was performed with caution and subsequently a proximal wall of the apical third was worn down until the file was observed inside the duct, observed and studied with the help of a magnifying glass. The working length was acceptable when the locator determined that it was between 0.5-1.5 mm of the cement-dentin-duct limit; short when it was more than 1.5 mm and long when it was observed that it exceeded the cement-dentine-duct limit. Results: The accuracy of 95.7 percent (135) of the measurements was acceptable and only 13(9.2 percent) ducts had instability, with an existing relationship between the accuracy and instability of the measurements. It was observed that 88(62.4 percent) ducts with secretions obtained an acceptable one in the determination of the length of work. Only 3 (2.1 percent) ducts with secretions had short measurements. The presence of secretions was not significant to assess the accuracy. Conclusions: The measurements of the working lengths using the locator studied were, almost entirely, of acceptable precision and were practically unstable. Similarly, the presence of secretions inside the root canals did not significantly affect the accuracy of the localizer in question(AU)

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.

Micro-computed tomographic assessment of the variability and morphological features of root canal system and their ramifications

Abstract Objectives This study assessed the incidence and variability features of root canals system (RCS) and their ramifications according to Pucci & Reig (PR) (1944) and the American Association of Endodontists (AAE) (2017) by micro-computed tomography (μCT). Methodology 500 representative extracted human teeth of each tooth group (n=50) (maxillary/mandibular central and lateral incisors, canines, first and second premolars and molars) were scanned by μCT with a resolution of 26.70 μm. The reconstructed cross-sections images and the visualization of the continuous slices in the transversal axis were performed using DataViewer software. RCS were classified according to Pucci & Reig (main canal, collateral canal, lateral canal, secondary canal, accessory canal, intercanal, recurrent canal) and AAE (main canal, accessory canal, lateral canal). The apical deltas were assessed for both classifications. The prevalence of apical deltas was evaluated using the Chi-squared test (p<0.05). Results According to PR, a higher incidence of lateral canals was observed in maxillary canines (10%), central incisors (8%) and first premolars (6%). Using AAE, the highest incidence of lateral canals was observed in the mandibular first premolars (85%), first and second molars (84%), lateral incisors (67%), canines (59%), and in maxillary first premolars (52%). Regarding accessory canals, the PR showed a frequency in 2% of the maxillary lateral incisors and maxillary and mandibular first premolars and 3% of mandibular first and second molars. On the other hand, the AAE showed the highest incidence of accessory canals in 86% of the maxillary first premolars, 71% in mandibular lateral incisors, 69% in mandibular first premolars, 65% in mandibular canines, and 56% in maxillary canines. The PR showed the lowest incidence of apical deltas for all dental groups when compared with AAE (p=0.004). Interestingly, distal canals in maxillary molars showed a significant discrepancy between classifications (p=0.027). Conclusions μCT enabled accurately describing the RC system and related ramifications, adding to the PR and AAE classifications, with some discrepancies reported for maxillary molars. Clinical Relevance This μCT study enabled a thorough description of the variability among root canals and their ramifications, including clinically relevant details on the presence and location of lateral canals and accessories in all human tooth groups, beyond the currently existing classification systems.

Accuracy of Four Electronic Apex Locators During Root Canal Length Determination / Precisión de Cuatro Localizadores de Ápice en la Determinación de la Longitud de Trabajo

ABSTRACT: The apical limit of tooth roots for instrumentation and obturation is a controversial subject due to the high morphological complexity presented by the apical zone of the root. The development of electronic apex locators (EALs) has made working length (WL) determination more predictable, producing more accurate results; however, the interpretation mechanisms of different devices may affect measurements taken under different clinical conditions. One hundred premolars were used to compare the effectiveness of Propex II, Raypex 6, Propex Pixi and Root ZX II in locating the apical foramen (AF). No statistically significant differences were observed when the accuracy of measurement was compared between the different groups of EALs, however Root ZX II and Raypex 6 presented the best overall performance.

RESUMEN: El límite apical radicular para la instrumentación y obturación es un tema controversial, debido a la alta complejidad morfológica que presenta la zona apical de la raíz. El desarrollo de localizadores de ápice electrónicos (EALs) ha hecho la determinación de la longitud de trabajo (WL) más predecible y con resultados más precisos. Sin embargo, el mecanismo de interpretación de cada dispositivo puede afectar la determinación de las mediciones en diferentes condiciones clínicas. Cien premolares fueron utilizados para comparar la efectividad de Propex II, Raypex 6, Propex Pixi y Root ZX II en localizar el foramen apical (AF). No se observaron diferencias estadísticamente significativas cuando se comparó la precisión de medición entre los diferentes grupos de EALs, sin embargo, Root ZX II y Raypex 6 mostraron un mejor desempeño global.

A 10-year Follow-up Study of 119 Teeth Treated with Apical Surgery and Root-end Filling with Mineral Trioxide Aggregate.

INTRODUCTION: The objective of this clinical study was to assess the long-term outcome (clinical signs/symptoms and radiographic healing) of teeth treated with apical surgery and mineral trioxide aggregate (MTA) for root-end filling. METHODS: One hundred ninety-five patients were recalled 1, 5, and 10 years after apical surgery for clinical and radiographic examinations. Three calibrated observers evaluated the periapical radiographs independently. The evolution of the cases over time was analyzed. Healing classification of teeth was divided into "healed" versus "not healed" teeth using well-established clinical and radiographic healing criteria. The potential influence of sex, age, type of treated tooth, type of MTA, and first-time versus repeat surgery on healing outcome was statistically analyzed. RESULTS: The inception cohort included 195 teeth. The dropout rate after 10 years amounted to 39% (n = 76). Of the 119 teeth available for the 10-year analysis, 97 teeth were classified as healed (81.5%). No significant differences were found with regard to the rate of healed cases for the subcategories of the parameters of age, sex, type of MTA, and first-time or repeat surgery. Concerning the type of treated tooth, the rate of healed maxillary molars (95.2%) differed significantly (P = .035) from the rate of healed maxillary premolars (66.7%). The predictive value of the cases classified as healed at 1 year and remaining so over the 10-year observation period was 86.8%. CONCLUSIONS: This 10-year follow-up study of teeth treated with apical surgery and MTA as root-end filling material showed an acceptable rate of healed cases. Many of the lost teeth had been extracted because of longitudinal root fractures during the observation period.

The evaluation of apicectomy without retrograde filling in terms of lesion size localization and approximation to the anatomic structures.

BACKGROUND: The purpose of this study was to evaluate of the patients who underwent apical resection. Besides assess the classification of resection side, localization, lesion size, approximation of anatomic structures and the purpose of the apical surgery retrospectively. MATERIAL AND METHODS: In this stutdy 782 patients and 1191 apical resection applied tooth evaluated. 504 of the patients were famale and 278 were male. Patients age was between 13 and 76 years old and operated between January 2016 and January 2017. The study includes incisor, canine and premolar teeth which had the apical resection as the first time. Operation side evaluated from orthopantomograph and periapical radiographs. RESULTS: There were 1191 teeth operated and 966 of them in maxilla and 225 of them in mandible. The number of the incisor teeth were 871, 177 were canine, 129 were premolar and one of them was molar. The total amount of 468 patients had operated by just 1 tooth, 454 of the operated teeth had cyst on the operation side. Premolar and molar side 21 of the 93 lesion had approximation with maxillar sinus. On the other hand in maxilla 39 of 569 lesion had approximation with nasal cavity. In mandibula 1 of the 15 lesion, which involved mandibular premolar teeth, had approximation with mental foramen. CONCLUSIONS: Apical resection operation mostly done for one tooth, and the lesion size was less than 10 milimeters. Furthermore apical resection mostly done for incisors cause of odontogenic cyst.

Is Hypoxia Related to External Cervical Resorption? A Case Report.

Despite the fact that external cervical resorption (ECR) is a well-known and rather frequently met condition, the driving force of this phenomenon still remains unclear. Recently, hypoxia has been linked to ECR. Thus, the aim of this work was to investigate the existence of hypoxia in ECR and hypothesize on its role at the time of extraction. This work is a case study of a tooth with ECR. ECR diagnosis was based on clinical and radiographic examination with cone-beam computed tomographic imaging. The extracted tooth was further analyzed by using nanofocus computed tomographic imaging and immunohistology. To investigate the 3-dimensional extent and pattern of ECR, in vivo cone-beam computed tomographic imaging and ex vivo nanofocus computed tomographic imaging were used. Different histologic stains were used to investigate the presence of a hypoxic environment and to gain a better insight into the involved cells, neuronal structures, and remodeling process during ECR. A higher distribution of hypoxia-inducible factor 1a-positive cells was found in the apical part of the resorption area when compared with the coronal area of the resorption. In addition, a similar distribution of hypoxia-inducible factor 1a-positive odontoblasts was observed in the pulp. Three-dimensional analysis of the calcification of the pulp revealed the formation of pulp stones in areas with higher hypoxia. Histology showed that remodeling during ECR can occur according to a layered pattern. This investigation confirms the presence of hypoxia in ECR and shows that there is a gradient of hypoxia within the ECR lesion and surrounding tooth structure. The hypoxic environment within the pulp is also indicated by the formation of pulp stones.

Distances of root apices to adjacent anatomical structures in the anterior maxilla: an analysis using cone beam computed tomography.

OBJECTIVES: The aim was to assess the anatomical relationship of anterior maxillary teeth to the nasal floor in patients referred for apical surgery. MATERIALS AND METHODS: Cone beam computed tomographic images (CBCT) of 83 patients were analysed retrospectively to quantify the distances between the root apices of maxillary anterior teeth (canine to canine) to the nasal floor or maxillary sinus (whichever was closer). Secondary outcome variables were the distances of the periapical lesion to the nasal floor, distances of the apices to the labial and palatal bone plates as well as to the neighbouring teeth. RESULTS: A total of 93 teeth (39 central, 35 lateral incisors and 19 canines) were analysed. The mean shortest distances of the apices to the nasal floor (or maxillary sinus) were 8.54 mm for central incisors, 9.49 mm for lateral incisors and 5.39 mm for the canines. The canines exhibited a significantly shorter distance to the nasal floor/maxillary sinus. In the presence of an osteolysis, the distance to the nasal floor was significantly shorter compared to the teeth without lesions. The lateral and central incisors showed significant proximity to each other at the level of the future surgical resection (3 mm from the apex). CONCLUSIONS: A close proximity between apices and adjacent anatomical structures such as nasal floor, maxillary sinus or adjacent roots could be shown in some cases. CLINICAL RELEVANCE: CBCT could be a valuable adjunctive imaging tool prior to apical surgery in the anterior maxilla to assess the risk for and decrease the incidence of damage to neighbouring anatomical structures such as the nasal floor, maxillary sinus or adjacent roots.

Outcome assessment of apical surgery: A study of 234 teeth.

BACKGROUND/PURPOSE: Apical surgery is an option for management of endodontically-treated tooth with persistent periapical lesions or symptom and sign. The objective of this study was to investigate the correlation between the demography, preoperative, postoperative factors and healed rate of apical surgery. METHODS: Subjects were retrospectively collected from patients who received apical surgery/apicoectomy at the Endodontic Department, National Taiwan University Hospital from January 2013 to June 2015. The standard apical surgery procedures were performed. The demography, preoperative clinical and radiographic examination data as well as postoperative variables were collected. The outcome assessment was carried out after surgery. Statistical analysis was performed by chi square test to evaluate the potential outcome predictors. RESULTS: Total 187 patients and 234 teeth receiving apical surgery were included. 53 male and 134 female patients were collected. The age was ranged between 17 and 89 years old and the mean age was 43.64 years old. Better healed rate with significant differences were observed in female patient (p < 0.05), age ≤60 years old (p < 0.01), preoperative root canal filling material >2 mm short of apex (p < 0.01), lesion size from ≤2 mm to ≤12 mm (p < 0.05) and follow-up period â‰§12 months (p < 0.01) groups. CONCLUSION: Gender, age, preoperative root canal filling material extent, lesion size and follow-up period may affect the outcome of apical surgery. Tooth type, post, prosthesis, and lesion area showed no marked effect on apical healing. These results provide more detailed information for the clinical practitioners to make treatment plans and are important for clinical endodontic practices.

Effects of Different Glide Path Files on Apical Debris Extrusion in Curved Root Canals.

INTRODUCTION: Creating a glide path before root canal preparation with nickel-titanium rotary files is essential to prevent the file fracture and to maintain the original root canal configuration. Both rotary glide path files and manual K-files are used to create a glide path. The aim of this study was to compare the amount of apically extruded debris after using different glide path files before preparing curved root canals with the WaveOne Gold single-file reciprocating system (Dentsply Maillefer, Ballaigues, Switzerland). METHODS: Sixty extracted mandibular first molar teeth with curved mesial roots were selected for this study. The mesial roots of the teeth were removed from the cementoenamel junction. Cone-beam computed tomographic imaging was used to evaluate the curvature of the mesial root canals. Specimens were randomly divided into 6 experimental groups according to the root canal preparation (n = 10): group G-File, a glide path with G-Files (Micro-Mega, Besancon, France) + WaveOne Gold preparation; group One G, a glide path with One G (Micro-Mega, Besancon, France) + WaveOne Gold preparation; group ProGlider, a glide path with ProGlider (Dentsply Maillefer) + WaveOne Gold preparation; group PathFile, a glide path with PathFiles (Dentsply Maillefer) + WaveOne Gold; group K-files, a glide path with a K-file + WaveOne Gold preparation; and group without a glide path, WaveOne Gold preparation without a glide path file. Roots were attached to preweighed Eppendorf tubes. All instruments were used according to the manufacturers' instructions. During root canal preparation, a total of 8 mL distilled water was used for each specimen. Apically extruded debris was collected in Eppendorf tubes. After the completion of root canal preparation, Eppendorf tubes were removed from the specimens and stored in an incubator at 68°C for 5 days. Eppendorf tubes were weighed after evaporation to calculate the amount of extruded debris. The data were statistically analyzed with 1-way analysis of variance and post hoc Tukey honest significant difference tests (P = .05). RESULTS: A statistically significant difference was observed between the One G and K-File groups. The One G group was associated with significantly less debris extrusion than the K-file group. There was no statistically significant difference between K-files and ProGlider, G-Files, PathFiles, and WaveOne Gold without a glide path, and also there was no statistically significant difference between One G and ProGlider, G-Files, PathFiles, and WaveOne Gold without a glide path. All experimental groups caused apical debris extrusion. CONCLUSIONS: Under the conditions of this in vitro study, all rotary path file systems were associated with similar apical debris extrusion before preparing root canals with the WaveOne Gold single-file reciprocating system. K-files caused more apically extruded debris than the One G files.

Anatomic Study of Mandibular Posterior Teeth Using Cone-beam Computed Tomography for Endodontic Surgery.

INTRODUCTION: The present study aimed to anatomically assess mandibular posterior teeth using cone-beam computed tomographic (CBCT) imaging for endodontic surgery. METHODS: A total of 170 CBCT scans were evaluated for anatomic variations of mandibular posterior teeth. All the scans were obtained using a Planmeca Promax CBCT unit (Planmeca, Helsinki, Finland) with exposure settings of 90 kVp, 12 mA, 12 seconds, and 0.3-mm resolution. All CBCT images were reconstructed by Romexis Viewer 3.8.2. software (Planmeca) on a 16-inch LCD monitor (22MP47HQ; LG, Seoul, South Korea), and axial, coronal and sagittal views were evaluated. RESULTS: The thickest buccal cortical plate was observed over the distal root of second molars (12.30 mm) among the molar teeth and over the second premolar root (5.41 mm) among the premolar teeth. The thinnest buccal cortical plate was observed over both the first and second premolar roots (0.42 mm) and over the mesial root of the first molar (0.62 mm) tooth. A 20.38-mm section was removed for surgical access during buccal resection of the distal root of the left second molar, and the closest distance from the apex to the inferior alveolar canal was 0 mm. CONCLUSIONS: Adequate knowledge of the anatomic dimensions of teeth and their surrounding structures is imperative for endodontic surgery. Information concerning the root thickness of mandibular posterior teeth at the site of root resection (apical 3 mm), buccal cortical plate thickness, and the distance from the apex of each tooth to the inferior alveolar canal and mental foramen can guide the surgeon before and during surgery.

Targeted Endodontic Microsurgery: A Novel Approach to Anatomically Challenging Scenarios Using 3-dimensional-printed Guides and Trephine Burs-A Report of 3 Cases.

Endodontic microsurgery (EMS) techniques have increased success rates over traditional approaches. Despite surgical advances, anatomically challenging scenarios can preclude EMS in certain cases. The aim of this article was to introduce targeted EMS, which uses 3-dimensional-printed surgical guides (3DSGs) and trephine burs to achieve single-step osteotomy, root-end resection, and biopsy in complex cases. In each of 3 cases, a 3DSG with a trephine port was printed using computer-aided design/computer-aided manufacturing implant planning software. The osteotomy site, angulation, and depth of preparation were defined preoperatively to avoid sensitive anatomic structures. The 3DSG was inserted at the target site to achieve precise osteotomy and root-end resection during surgery. A hollow trephine rotated within the 3DSG port produced single-step osteotomy, root-end resection, and biopsy. Root-end preparation and fill were accomplished, and tissues were sutured in place. Targeted EMS potentiated successful surgical treatment in 3 anatomically challenging scenarios: (1) a palatal approach to the palatal root of a maxillary second molar, (2) a facial approach to a fused distofacial-palatal root of a maxillary first molar, and (3) a mandibular second premolar in close proximity to the mental foramen. Trephine burs guided by 3DSGs produce efficient targeted osteotomies with a predictable site, angulation, and depth of preparation. Apical surgery in challenging anatomic cases such as the palatal root of the maxillary second molar, fused molar roots, and root ends in approximation to the mental nerve are possible with targeted EMS.