Canal Path Research Articles

Limitations and Management of Dynamic Navigation System for Locating Calcified Canals Failure

Nonsurgical endodontic teeth treatment with severe pulp canal obliteration poses challenges, primarily locating canals. By combining 3-dimensional reconstruction and spatial location registration, the dynamic navigation technique uses an optical tracking system to guide the clinician to drill in real time according to the predesigned path until access to the canal is established. Several in vitro studies and case reports have shown that calcified canal location with dynamic navigation system (DNS) is more accurate and efficient, yet the technique has limitations. In 4 cases with 7 teeth, this work presents manipulation process and clinical outcomes of DNS helping in calcified canal location. We performed handpiece adaptation and elucidated the failure to locate the canals with DNS in 2 teeth, resulting in canal geometry alteration and canal path deviation. Subsequently, the more experienced endodontist located the canals by combining cone-beam computed tomographic imaging and dental operating microscopy. All patients were completely asymptomatic after treatment. At the 1-year follow-up visit, the bone healing of periapical lesions progressed well according to the periapical radiography or cone-beam computed tomographic imaging. These findings indicate that DNS is a promising technique for locating calcified canals; however, it needs to be refined before clinical use.

Influence of Coronal Flaring on the Shaping Ability of Two Heat-Treated Nickel-Titanium Endodontic Files: A Micro-Computed Tomographic Study.

Nickel-titanium (NiTi) usage is associated in endodontics with some complications including canal transportation. Centering ability of a NiTi file is the ability to stay centered in the root canal system during instrumentation. Any undesirable deviation from the natural canal path is indicated as canal transportation. A possible strategy to improve the centering ability of NiTi instruments is the pre-enlargement of the coronal third of the root canal to minimize coronal interferences. This procedure is known as coronal flaring. The aim of this study was to perform a micro-computed tomographic (micro-CT) evaluation of the effect of coronal flaring on canal transportation and centering ability of two heat treated nickel-titanium rotary instruments, 2Shape (Micro Mega, Besançon, France) and HyFlex CM (Coltène Whaledent, Altstätten, Switzerland). Thirty extracted mandibular molars with two independent mesial canals were selected and randomly instrumented (n = 15 canals) with One Flare (Micro Mega, Besançon, France) before HyFlex CM, HyFlex CM (without coronal flaring), One Flare before 2Shape and 2Shape (without coronal flaring). One Flare (Micro Mega, Besançon, France) was introduced 4 mm below the canal entrance for canals prepared with coronal flaring. HyFlex CM and 2Shape were used accordingly to manufacturers’ instructions. New files were used for each canal. During and after instrumentation, irrigation procedures were performed. Micro-CT images were obtained pre- and post-preparation to measure and record root canal transportation and centralization. They were reconstructed from root apex to canal orifices, generating approximately 1000 sections per specimen. The anatomical thirds were determined by dividing the number of cross-sectional slices by three. Root canal transportation and centralization were determined by Gambil method, and the mean values were analyzed by repeated measures analysis of variance followed by multiple comparisons of Bonferroni to compare the different instrumentations procedures and the root thirds (p < 0.05). As for root canal transportation, 2Shape reported significantly higher values compared to HyFlex CM in the cervical region independently from the coronal flaring. In the apical region, 2Shape caused significantly minor canal transportation when used with coronal flaring with compared with the absence of coronal flaring. Regarding the centralization, HyFlex CM showed higher values than 2Shape in the cervical, independently from coronal flaring. In the apical region, 2Shape with coronal flaring exhibited significant major centering ratio, compared with not. Within the limitations of this study, coronal flaring reduced canal transportation and improved centralization of the 2Shape files in the apical section while it had no significant influence on shaping ability of the HyFlex CM instruments. Coronal flaring could represent a valid strategy to improve the shaping ability of NiTi files knowing that its benefit could be influenced by the shaping file used.

Micro-CT assessment of radicular pulp calcifications in extracted maxillary first molar teeth.

The present study aimed to evaluate the frequency, position, and length of radicular pulp calcifications in three-rooted maxillary first molars using micro-computed tomography. Two hundred three-rooted maxillary first molars were scanned at a pixel size of 10µm and reconstructed using similar parameters. Three-dimensional models of the mesiobuccal (MB1, MB2, MB3), distobuccal (DB), and palatal (P) canals were qualitatively evaluated for discontinuity in the canal path. Transaxial and sagittal cross-sectional images of the roots were further screened, and the complete obliteration of the canal lumen by pulp calcification was identified when the canal had similar radiodensity to the surrounding dentine. Then, the number, position, and length of the calcifications were recorded for each root. Intra-observer agreement was performed using Cohen's kappa test, while one-way ANOVA and Duncan tests compared the lengths of calcifications among the canals, with α = 5%. Intra-observer agreement was perfect for identification of pulp calcifications (ĸ = 1.0; p = 0.000). MB2 and MB3 canals accounted for the highest percentage frequency of calcifications distributed throughout the canal path. In the MB1, DB, and P canals, they occurred mainly at the apical third. Lengths of calcifications were greater in the MB3 (0.89 ± 0.81mm) and MB2 (0.82 ± 0.93mm) canals than in the MB1 (0.39 ± 0.32mm), DB (0.34 ± 0.22mm), and P (0.28 ± 0.22mm) canals (p < 0.05). MB2 and MB3 canals accounted for the highest frequency and length of radicular pulp calcifications. In the MB1, DB, and P canals, calcifications occurred mostly at the apical third, while in the MB2 and MB3, most of calcifications were observed at the orifice level and along the canal path. In maxillary first molars, radicular pulp calcifications are mainly located at the apical third of the MB1, DB, and P canals, while in the MB2 and MB3 canals, most of them are at the orifice level or along the canal path.

A natural experimental study of improvements along an urban canal: impact on canal usage, physical activity and other wellbeing behaviours

BackgroundThere are few robust natural experimental studies of improving urban green spaces on physical activity and wellbeing. The aim of this controlled natural experimental study was to examine the impact of green space improvements along an urban canal on canal usage, physical activity and two other wellbeing behaviours (social interactions and taking notice of the environment) among adults in Greater Manchester, UK. The intervention included resurfaced footpaths, removal of encroaching vegetation, improved entrances, new benches and signage.MethodsTwo comparison sites were matched to the intervention site using a systematic five-step process, based on eight correlates of physical activity at the neighbourhood (e.g. population density) and site (e.g. lighting) levels. Outcomes were assessed using systematic observations at baseline, and 7, 12 and 24 months post-baseline. The primary outcome was the change in the number of people using the canal path from baseline to 12 months. Other outcomes were changes in physical activity levels (Sedentary, Walking, Vigorous), Connect and Take Notice behaviours. Data were analysed using multilevel mixed-effects negative binomial regression models, comparing outcomes in the intervention group with the matched comparison group, controlling for day, time of day and precipitation. A process evaluation assessed potential displacement of activity from a separate existing canal path using intercept surveys and observations.ResultsThe total number of people observed using the canal path at the intervention site increased more than the comparison group at 12 months post-baseline (IRR 2.10, 95% CI 1.79–2.48); there were similar observed increases at 7 and 24 months post-baseline. There was some evidence that the intervention brought about increases in walking and vigorous physical activity, social interactions, and people taking notice of the environment. The process evaluation suggested that there was some displacement of activity, but the intervention also encouraged existing users to use the canal more often.ConclusionsUrban canals are promising settings for interventions to encourage green space usage and potentially increase physical activity and other wellbeing behaviours. Interventions that improve access to green corridors along canals and provide separate routes for different types of physical activities may be particularly effective and warrant further research.Study protocolStudy protocol published in Open Science Framework in July 2018 before the first follow-up data collection finished (https://osf.io/zcm7v). Date of registration: 28 June 2018.

Quantitative analysis of bony birth canal for periacetabular osteotomy patient by template fitting

Periacetabular osteotomy (PAO) is a joint preservation procedure for developmental dysplasia of the hip. Such a procedure requires osteotomy of the medial wall of the acetabulum, which may cause the narrow of the bony birth canal and increase the risk of complications during the childbirth process in the future. Using quantitative analysis of the bony birth canal to determine the risk of complications for the childbirth process remains a challenging task. The purpose of this paper is to explore a new 3D CT measurement method to quantify the narrowest parameters of the bony birth canal of the female patients with hip dysplasia before and after unilateral PAO surgery. By analyzing the impact of PAO surgery on the bony birth canal, the patient’s risk of complications during the childbirth process in the future can be estimated, and it can be utilized for doctors to determine the impact of unilateral PAO for choosing appropriate delivery method. In this paper, a mean shape of the preoperative pelvises is obtained by using the statistical shape model algorithm, and the mean shape includes pelvic shape features of all the preoperative pelvises, and it can be utilized as the standard pelvic template. A bidirectional iterative algorithm is used to generate a standard bony birth canal path template. Then, the pelvic registration and principal plane deformation constraint are utilized to calculate the optimal bony birth canal path. The proposed method is verified in 31 cases of CT data with the approval of the institutional review board. The test data contain preoperative and postoperative CT images. Compared with the benchmark method, the measurement accuracy of the narrowest position and diameter of the bony birth canal is improved by 65% and 78%, respectively. In addition, the processing speed is increased by 32%. Experimental results demonstrate that the proposed method has high accuracy and validity for quantifying the bony birth canal. The proposed method can measure the anatomical parameters of the bony birth canal accurately. In addition, the doctor can make optimal planning for childbirth with the help of the quantitative analysis of the bony birth canal.

A new teaching model with artificial teeth containing simulated pulpal tissue

This study aimed to evaluate the use of artificial teeth for endodontic training for dental students. The following aspects of the artificial teeth were approved by the endodontists in Isfahan University of Medical Science: internal and external anatomy; coronal pulp chambers regarding their size, shape, and canal path; the root canals regarding their size, shape, and position; filling the pulp chamber and root canals by considering the texture, quantity, color, and ease of handling; and resin hardness and visualization of the radiographic image. The results showed favorable opinions regarding the internal and external anatomy, coronal pulp chamber, root canal (s), handling, and radiographic imaging. The contents of the pulp space and hardness of the teeth were satisfactory. The artificial teeth tested have the potential to replace the natural teeth in preclinical training.

Canal transportation and centering ability of root canals prepared using rotary and reciprocating systems with and without PathFiles in cone-beam computed tomography-based three-dimensional molar prototypes

Background:It is important to use instruments that cause minimal changes in the canal path for root canal preparation. There is inadequate literature comparing rotary and reciprocating systems and hand files. No study used three-dimensional printed models to compare rotary, reciprocating, and hand files.Aims:We aimed to assess the canal transportation and centering ability of WaveOne Gold, ProTaper Gold, and NiTi Flex K-file systems with and without glide path preparation.Material and Methods:Forty-nine resin models were randomly divided into Group I A – WaveOne Gold with WaveOne Gold Glider and Group I B – WaveOne Gold without glide path; Group II A – ProTaper Gold with ProGlider and Group II B – ProTaper Gold without glide path; and Group III A – NiTi Flex K-files with no. 10 stainless steel K-file and Group III B – NiTi Flex K-files without glide path. Pre- and postinstrumentation cross-sectional images at levels 3, 5, 7, 9, and 11 mm were compared.Results:WaveOne Gold caused the least canal transportation and improved centering ability (P < 0.05). NiTi Flex K-files transported the canal more than others in the apical levels (3, 5 mm). Glide path creation reduced canal transportation and improved canal-centering ability.Conclusions:WaveOne Gold system has better centering ability and lesser canal transportation than ProTaper Gold and NiTi Flex K-file. Glide path creation reduced canal transportation and improved canal-centering ability.

Electrochemical dissolution of nickel-titanium instrument fragments in root canals of extracted human maxillary molars using a small reservoir of electrolyte.

To evaluate the viability of the electrochemical dissolution of fragments of fractured NiTi instruments in root canals of extracted human maxillary molars, using two electrodes and the solution restricted to a small reservoir coupled to the pulp chamber. The primary hypothesis was that this method enables the reduction of fragment volume and re-establishment of the root canal path with a size 08K-file, both in simulated canals and in extracted human maxillary molars. Fragments of F1 ProTaper instruments were polarized in simulated root canals and in distobuccal root canals of extracted maxillary molars using a new method, with the solution restricted to a small acrylic microcell coupled to each resin block or pulp chamber. Two electrodes were used, where one was kept in contact with the intracanal fragment and another was positioned in the solution present in the acrylic microcell. After the tests, a size 08K-file was used passively to verify the possibility of bypassing the fragment, which was also confirmed by radiographic analysis. Micro-CT analysis of the teeth was used before and after fragment dissolution to evaluate the volume, length and porosity of the fragments. The D'Agostino-Pearson normality test was used to verify the distribution of the data. A paired t-test (P<0.05) was used to compare the volume, length and porosity of the fragments before and after the dissolution tests. After dissolution, all fragments could be bypassed with a size 08K-file in both simulated canals and in extracted teeth. The dissolution process did not result in significant reduction of neither the fragment length nor the fragment porosity. However, it resulted in a significant reduction of fragment volume (paired t-test, P<0.05). The electrochemical dissolution of fragments of NiTi files in root canals of extracted human maxillary molars using two electrodes, and the solution restricted to a small reservoir coupled to the pulp chamber resulted in a significant reduction of fragment volume. The re-establishment of the root canal path with the passive insertion of size 08K-files was possible in all samples after the tests, both in simulated canals and in extracted teeth.

Analysis Of The Potential For Cbl Inland Waterways As An Alternative Transport Logistics Using AHP

Economic growth in Indonesia gives effect to the development of the logistics industry in Indonesia. Logistics Business is a sector that has a fairly high growth rate, where increasingly improved growth requires effective and efficient logistical support. In 2018, the Government of West Java implement the Innovation Inland Waterways which aims to create a channel width of the sea into the mainland so that containers can be transported by water rather than through the toll-road to Tanjung Priok, and make Inland Waterways as an Alternative Transportation logistics, Central Government, also has made Inland Waterways Cikarang Bekasi Laut (CBL) as the National Strategic Projects, which is expected to reduce the current density on the land logistics from Cikarang Industrial Area to the Port of Tanjung Priok and aim to optimize the potential of the river as an alternative canal path of transport logistics. Where the volume of land transport logistics in Indonesia has reached nearly 90%, and with the construction of CBL Inland Waterways is expected to reduce costs with the integration of multimodal transport logistics. The purpose of this study was to find a potential that can be developed as Alternative Transportation Logistics and determines the priority level of that potential. Retrieval of data taken through a questionnaire distributed to experts in the field of logistics and related to the research being carried out. The result indicated that the Economic aspect was the top priority among the other potential to developed.

Prevalence and position of mandibular incisive canal, anterior loop of the mandibular canal and lingual foramen using cone beam computed tomography

Objective: Comprehensive knowledge about the anatomy of the surgical site is an important prerequisite for any surgical procedure. This study aimed to assess the prevalence, position and anatomical characteristics of mandibular incisive canal (MIC), lingual foramen (LF) and anterior loop of the mandibular canal (ALMC) in an Iranian population using cone beam computed tomography (CBCT). Materials and Methods: This study was conducted on 103 patients who underwent CBCT prior to implant placement. The CBCT scans of patients were evaluated by two observers to determine the visibility and length of MIC, LF and ALMC. The buccolingual inclination of MIC at the initiation point of canal and canal path were also studied. Results: The prevalence of MIC, LF and ALMC was 90%, 76% and 84% on CBCT scans, respectively. The mean length of MIC and ALMC was 7.5mm and 1.2mm, respectively and the mean width of LF was 0.9mm. The MIC had a buccal inclination at the initiation point and approximated the lingual plate as extended towards the midline. Analytical statistics including independent samples t-test, paired samples t-test, ANOVA analyses were applied. Conclusion: Considering the high prevalence of MIC, ALMC and LF and wide range of MIC (1.2mm to 20mm) and ALMC (1mm to 9.9mm) length, CBCT is recommended for patients prior to surgical procedures in the anterior mandible to determine the exact location of these anatomical structures.

Integration of remote sensing data and in situ measurements to monitor the water quality of the Ismailia Canal, Nile Delta, Egypt.

The Ismailia Canal is one of the most important tributaries of the River Nile in Egypt. It is threatened by extinction from several sources of pollution, in addition to the intersection and nearness of the canal path with the Bilbayes drain and the effluent from the two largest conventional wastewater treatment plants in Greater Cairo. In this study, the integration of remote sensing and geospatial information system techniques is carried out to enhance the contribution of satellite data in water quality management in the Ismailia Canal. A Landsat-8 operational land imager image dated 2018 was used to detect the land use and land cover changes in the area of study, in addition to retrieving various spectral band ratios. Statistical correlations were applied among the extracted band ratios and the measured in situ water quality parameters. The most appropriate spectral band ratios were extracted from the NIR band (near infrared/blue), which showed a significant correlation with eight water quality metrics (CO3, BOD5, COD, TSS, TDS, Cl, NH4, and fecal coliform bacteria). A linear regression model was then established to predict information about these important water quality parameters along Ismailia Canal. The developed models, using linear regression equations for this study, give a set of powerful decision support frameworks with statistical tools to provide comprehensive, integrated views of surface water quality information under similar circumstances.

Effect of heat treatment on the centering ability and dentin removal of a nickel–titanium single file rotary system

Aim The aim of this study was to investigate the effect of heat treatment on the centering ability and amount of dentin removal of OneShape single file rotary system (OS) by cone beam computed tomography. Materials and methods Twenty human premolars with single root canals were allocated into two equal groups (n = 10) according to the used rotary system: group 1: OS system, group 2: One Curve which is heat-treated OS single file rotary system. Preinstrumentation and postinstrumentation images were obtained at 3, 6, and 9 mm from the apex and assessed to determine canal centering ability. Amount of removed dentin was estimated by difference between preinstrumentation and postinstrumentation root canal volumes. Data were analyzed using t-test and significance level was set at P value less than or equal to 0.05. Results The results showed that One Curve file has higher mean centering ratio and more dentin removal than OS file with no statistically significant difference between them (P > 0.05). Conclusion It was concluded that heat treatment did not have significant effect as both files could maintain the original canal path without significant differences in centering ability and amount of removed dentin.

Three-Dimensional Changes of the Auditory Canal in a Three-Year Period during Adolescence Using CBCTs.

Purpose There is a lack of identifying suitable regions in the head that can be used for three-dimensional superimposition techniques. For this reason, with the use of cone-beam computed tomography (CBCT), the ear canals were analyzed to verify changes during a period of three years in the adolescent years. Methods CBCTs from fifty-six patients (ages: 10 to 20) were used to landmark the anatomy of the ear canals. Each patient was analyzed using two CBCT reconstructions that were taken approximately three years apart. AVIZO® software was used to locate 28 landmarks distributed following the ear canal path and foramina (ovale, spinosum, rotundum, etc.) in the cranial base to obtain spatial relationships. Three-dimensional coordinates were obtained from the landmarks, and the average distance between various landmark pairings was calculated. The repeated measure ANCOVA was used to determine statistical significance. Results In the main data set, the largest mean distance change was found to be 4.37 mm ± 18.29 mm between the left foramen ovale and the left superior medial ear canal opening. The smallest mean distance change was 0.18 mm ± 3.25 mm between the right inferior lateral ear canal opening and the right inferior medial ear canal opening. Conclusions During the adolescent years, the ear canal presents dimensional changes. Even though in different areas throughout the canal, the average distances were minor, still, large standard deviations were present; thus, caution should be taken when trying to use this structure for superimposition of CBCTs.

Association between the Anatomy of the Mandibular Canal and Facial Types: A Cone-Beam Computed Tomography Analysis.

We evaluated the anatomical variations of the mandibular canal associated with various facial types, age, sex, and side of the face studied. We analyzed 348 hemimandibles in subjects without a history of trauma, lesions in the lower arch, or orthognathic or repair surgery in the posterior mandible. Facial type was determined using the VERT index. The canal path was classified as Type 1 (a large, single structure passing very close to the root tips); Type 2 (a canal passing closest to the mandibular base); and Type 3 (a canal present in the posterior mandibular region, with a lower canal running through the mandibular branch, reaching the anterior region). Bifid canals (type 3) were classified into four categories according to the course and number of mandibular canals. The brachyfacial and mesofacial types presented a Type 1 canal in 95.5% (n=166) of subjects, in dolichofacial types, 68.2% (n=45) presented a Type 2 canal, while in the mesofacial type, a lower prevalence of the bifid mandibular canal was observed (13.0%, n=23) than in the other facial types. The bifid canal showed significant association with facial type only (p < 0.05), but no significant association was observed with the anterior loop type (p > 0.05). Facial type is significantly associated with the path and morphological variations of the mandibular canal, independently of the side of the face studied, age, and sex.

Location of the course of the mandibular canal, anterior loop and accessory mental foramen through cone-beam computed tomography.

This study aimed at identifying the course of the mandibular canal, the presence of anterior loop and accessory mental foramen, as well as verifying the association between these variables through the analysis of cone beam computed tomography (CBCT) exams. CBCT images were analyzed to identify the type of mandibular canal path, classified into three types: (I) catenary; (II) progressive descending; and (III) straight. In addition, the presence of anterior loop and accessory mental foramen was analyzed. The variables were summarized by measures of absolute frequency, relative, mean and standard deviation. The Chi square and Fisher's exact tests were used in the comparative analysis of the frequency distribution. The level of significance was 5%. The most frequent mandibular canal course was straight type (74.4%), followed by catenary (19.4%) and finally the progressive descending (6.2%). It was observed a prevalence of 10.2% for anterior loop and 7.9% for accessory mental foramen. There was no association between the presence of anterior loop (P = 0.798) and accessory mental foramen (P 0.480) with the mandibular canal course pattern, as well as no association between the anterior loop and the presence of the accessory mental foramen (P = 0.407). The CBCT analysis is the best methodology for the investigation and localization of mandibular anatomical variations, which provides a good image quality of the bone tissue and details of the anatomical structures, reducing the risk of injury to the lower alveolar vascular-nervous bundle and, consequently, cause paralysis and hemorrhage in the anterior region of the mandible and adjacent structures.

Canal Transportation and Centering Ability of ProTaper and SafeSider in Preparation of Curved Root Canals: A CBCT Evaluation.

Introduction:Maintaining the original central canal path is an important parameter in efficient root canal preparation. Instruments causing minimal changes in original canal path are preferred for this purpose. This study sought to compare canal transportation and centering ability of ProTaper and SafeSider instruments in curved mesiobuccal root canals of mandibular first molars using cone beam computed tomography (CBCT). Methods and Materials :In this experimental study, 30 mesiobuccal root canals of extracted human mandibular first molars with 20° to 40° curvature were randomly divided into two groups (n=15). After mounting in putty, preoperative CBCT scans were obtained of teeth. Root canals in group A were shaped using S1, S2, F1 and F2 of ProTaper system. Root canals in group B were instrumented to size 25 using SafeSider system according to the manufacturers’ instructions. Postoperative CBCT scans were then obtained. The distance between the external root surface and internal canal wall was measured at the mesial and distal at 1, 3 and 7 mm from the apex. The values measured on primary and secondary CBCT scans were compared to assess possible changes in original central canal path and canal transportation. Data were compared using the t-test and repeated measure ANOVA. Results:ProTaper and SafeSider were significantly different in terms of canal transportation and centering ability, and ProTaper was significantly superior to SafeSider in this respect (P<0.001). Conclusion:ProTaper (in contrast to SafeSider) is well capable of maintaining the original central canal path with the least amount of transportation.

Centering ability and canal transportation of curved root canals after using different nickel–titanium preparation systems

Purpose To evaluate centering ability and canal transportation in curved root canals after using different nickel–titanium (Ni-Ti) preparation systems including two rotary systems [Revo-S and Twisted File (TF)] and hand Ni-Ti-Flex K-files using cone-beam computed tomography. Materials and methods Seventy-five extracted human premolars with similar range of canal curvature (25–35°) were used, after crown removal and working length determination, samples were randomly divided into three groups (n = 25) according to the type of instruments used. Group I (Revo-S), group II (TF) and group III (Ni-Ti-Flex). Preinstrumentation and postinstrumentation cone-beam computed tomography images were recorded at several root canal levels (3, 5, 7, 9, and 11 mm) from the apex under the same circumstances, superimposed and then the centering ability and canal transportation were calculated using specific equations. Results Revo-S system produced less mean value of canal transportation and more centering ability than TF and Ni-Ti-Flex systems. In addition, the middle canal level (7 mm) recorded the least mean value of transportation with the highest centering ability for all used instruments. Conclusion Preparation of curved root canal using rotary systems produced less change in original canal path compared with the hand Ni-Ti files.

Biometric Analysis of C-shaped Root Canals in Mandibular Second Molars Using Cone-Beam Computed Tomography.

The configuration of C-shaped root canals, root canal wall thickness and orientation of the thinnest area using CBCT in mandibular second molars were assessed. Seventy five CBCT scans were evaluated. Axial sections were evaluated to determine the configuration of C-shaped canals in the coronal, middle and apical regions. The root canal path from the orifice to the apex, the thinnest root canal wall and its orientation were all determined. Data were analyzed using one-way ANOVA and post hoc Tukey's test. The most common configurations were Melton's type I in the coronal and middle and types I and IV in the apical region. The mean thicknesses of the thinnest root canal wall were 1.94±0.43, 1.42±0.57 and 1.10±0.52 mm in the coronal, middle and apical regions, respectively. The lingual wall was the thinnest wall in the coronal, middle and apical regions and it was thinner in the apical than in the middle and coronal regions. The lingual wall was thinner in the middle third of the mesial root compared to the distal root (P<0.05). The lingual wall was the thinnest in C-shaped root canals of mandibular second molars of an Iranian population. Type, number and pathway of canals may vary from the orifice to the apex.

An analysis of proximal humerus morphology with special interest in stemless shoulder arthroplasty

Shoulder arthroplasty evolution has resulted in the shortening of traditional stemmed humeral components. Newer stemless implants rely on structures that maintain fixation in the metaphyseal region of the proximal humerus. Whereas the overall morphology of the proximal humerus is well understood, the advent of stemless implants requires that additional geometric measures be assessed. This study's purpose was to introduce new anatomic measures to assist with the design of stemless implants. Using computed tomography data from 98 subjects (nonarthritic [n = 41], B2 osteoarthritic [n = 26], and symmetric osteoarthritic [n = 31]), shifts in proximal canal direction, bounding diameters along the canal, and canal depth beneath the center of the humeral resection plane were quantified. Traditional articular aspect ratio terms (ie, resection diameter, humeral head height) were also quantified. All measures were reported relative to a humeral coordinate system relevant to stemless implants. Humeral depth, gender, and osteoarthritis were found to have effects on the measured parameters. Of these factors, gender was the most prominent, as men presented with significantly larger canal diameters and depths than women did (P < .001). Osteoarthritis had less of a significant impact on results (P < .001), with the attributed differences in canal path direction and articular aspect ratio being small in absolute value. Canal diameter was found to change significantly as a function of depth beneath the resection plane (P < .001). This work quantified 3 new morphologic terms relevant to proximal humerus stemless arthroplasty. Together, these outcome measures help define the spatial limits for stemless humeral arthroplasty in an implant-relevant coordinate system.

In vitro analysis of the internal anatomy of lower incisors by cone beam computerized tomography

For the success of endodontic treatment, the knowledge of the internal anatomy becomes essential. Objective: to analyze the prevalence of lower incisor canals in a clinical and tomographic analysis. Material and methods: 148 lower incisors were used, measured, and evaluated through periapical radiograph and computed tomography. Results: in relation to the number of canals, 107 teeth(72.3%) presented a single canal, while 41 teeth (27.7%) presented two canals. Of the 41 teeth presenting 2 canals, 3 teeth presented independent canals (2.03%) and 38 teeth had 2 canals that joined at some point of the canal path (25.67%). Conclusion: The prevalence of two canals in the lower permanent human incisors was 27.7%; of these, 2.03% were independent. The main point of root canal union was at the apical third (20.94%). The most commonly found root canal shape was round in cervical third, flattened in middle third, and round in third apical.