Assessing the role of the pelvic canal in supporting the gut in humans

The human pelvic canal (true pelvis) functions to support the abdominopelvic organs and serves as a passageway for reproduction (females). Previous research suggests that these two functions work against each other with the expectation that the supportive role results in a narrower pelvic midplane, while fetal passage necessitates a larger opening. In this research, we examine how gut size relates to the size and shape of the true pelvis, which may have implications on how gut size can influence pelvic floor integrity. Pelves and in vivo gut volumes were measured from CT scans of 92 adults (48 female, 44 male). The true pelvis was measured at three obstetrical planes (inlet, midplane, outlet) using 11 3D landmarks. CT volumetry was used to obtain an individual’s gut size. Gut volume was compared to the pelvic planes using multiple regression to evaluate the relationship between gut size and the true pelvis. We find that, in males, larger gut sizes are associated with increased mediolateral canal dimensions at the inlet and midplane. In females, we find that larger gut sizes are associated with more medially-projecting ischial spines and an anteroposteriorly longer outlet. We hypothesize that the association of larger guts with increased canal width in males and increased outlet length in females are adaptations to create adequate space for the gut, while more medially projecting ischial spines reduce the risk of pelvic floor disorders in females, despite its possible spatial consequences for fetal passage.

Effect of Root Canal Transportation by Minimally Invasive Endodontic Access on Canal Orifice Dentin

Background: Minimally invasive endodontics (MI Endo) with minimal dentin shaping prevents root canal fracture in endodontically treated teeth. Alternatively, reduction of the surgical field and limitation of the visual field by MI Endo make root canal shaping difficult. The purpose of this study is to analyze the effect of minimally invasive (MI) shaping of canal orifice dentin by evaluating the shaping characteristics of TruNatomy (TN), a Ni–Ti file developed for MI Endo.Methods: A J-shaped canal model was used to compare the final canal morphology formed using a MI shaping TN or conventional shaping ProTaper NEXT (PTN) file. The TN files were used in two experimental groups: no straight-line access (A) and straight-line access (B). The PTN files of the control were similarly classified: no straight-line access (C) and straight-line access (D). The increase in canal width and the median displacement (transportation) among the groups were compared.Results: The analysis of the canal width prepared with the TN file showed that the displacement of the inner canal curve increased at the point 5 mm from the apex in Groups A and B; however, the displacement of the outer width increased at the other measurement sites. In Groups C and D using PTN, the displacement of the inner canal curve increased at points 3–5 mm from the apex. Alternatively, the displacement on the outer width increased at 8 mm, and the displacement in Group D increased significantly. The canal transportation in the case with a TN file was 0.1 mm or smaller for Groups A and B, although the PTN preparation showed significant transport 3–5 mm from the apex on the inner curve of Group D compared with Groups A and B.Conclusions: TN shaping preserves the tooth structure and canal geometry without straight-line access. The TN file developed based on the concept of MI Endo facilitates accurate root canal shaping and reduces transportation.

551 The Relationship Between Canal Diameter and the DORR Classification - Presented by Dr John Vincent and Dr Ryan Doherty of NIMDTA, formerly Queen's University Belfast

Background Particularly in broach-only uncemented total hip arthroplasty, a narrow femoral canal presents a technical challenge. Traditionally such femurs have been considered to be Dorr A. To our knowledge, however, no study has reported on the relationship between isthmus width and the Dorr classification. Method We reviewed 500 high-quality, hard copy radiographs. Dorr classification and isthmus canal width were measured using an electronic caliper by 5 independent observers with intraobserver and interobserver error calculated. For this study, we defined a narrow canal as being 10 mm at its narrowest point (isthmus). Results Eight percent (40) were Dorr A, 85% (424) Dorr B, and 7% (36) Dorr C. With respect to isthmus width for Dorr A, 63% (25) were 10 mm compared to just 13% (55) of Dorr B. However, overall because there were more Dorr B femurs, 69% of those with an isthmus of 10 mm were Dorr B. Conclusions In this population, almost 70% of patients with an isthmus 10 mm were Dorr B, with only 30% being Dorr A. When using a broach-only technique, isthmus width should be routinely measured on the preoperative anteroposterior radiographs so as to alert the surgeon to potential problems.

The phenomenon of dental pulp sensitivity in the formation of permanent teeth

Aim. То carry out a comparative assessment of the change in the pain threshold (in terms of electroodontometry), the X-ray width of the root canal in the apex area and the nature of the pain sensation of the central incisors in children aged 6.5-15 years.Materials and methods. We examined 280 teeth in 280 children from 6.5 to 15 years old (central incisors). Patients are divided by age into 5 groups: 1 - 6.5-7 years old; 2 - 7-8 years old; 3 - 9-10 years old; 4 - 11-12 years old; 5 - 13-15 years old. The patients underwent electroodontometry (EOM), to measure the sensitivity threshold of the studied tooth, the subjective sensations with EOM were assessed, and the width of the apical part of the root canal was determined, according to the data of intraoral sighting radiography.Results. The study studied the process of teething and formation of teeth in dynamics from 6.5 to 15 years in 5 age groups. Changes in electrodontometry (EOM) are significant from 140.38 цА (4.5 years) to 24.38 цА (15 years) - average data. The relationship between age and the width of the root canal in the area of the apex, which is also characterized by a gradual narrowing, has been traced. Pulp pain with EOM becomes clearer and more short-lived with age. The correlation between age and pain threshold is less pronounced (41%) than between age and apical canal width (72%). Conclusions. The main role in the sensitivity of the tooth is played by the A-delta and C nerve fibers of the pulp. The phenomenon of a decrease in the pain sensitivity threshold of permanent teeth during electrodontometry in the process of root formation due to the reaction of C-fibers was established.

A computer tomography-based anthropomorphic study of forearm osteology: implications for prosthetic design

ABSTRACT BACKGROUND: The aim of this study was to accurately establish the variability in the anatomy of the radius and ulna in the context of the design of an intramedullary nail for both bones METHODS: Forearm computed tomography scans were used to measure the specific internal and external anatomy of the radius and ulna in adult patients. Patients with fractures or dislocations involving either the radius and/or ulna were excluded RESULTS: A total of 97 scans, comprising 84% male and 16% female patients, were included. The mean radius length was 238.43±18.38 mm (95% CI 234.60-241.74 mm). The mean curvature was an arc with a radius of 561.43±93.49 mm (95% CI 543.09-580.78 mm). The smallest measurement of the canal width was 5.17 mm (95% CI 4.87-5.47 mm). The ulna showed a mean length of 259.90±19.88 mm (95% CI 255.89-263.91 mm). The smallest measurement of the canal width was 4.80±1.30 mm (95% CI 4.53-5.87 mm). The mean proximal shaft angle was 11.39±3.30° (95% CI 10.76-12.82° CONCLUSION: This computed tomography scan-based anthropomorphic study has identified novel anatomical features and associations of human forearm bones. This information will be used in the design and manufacture of anatomic intramedullary devices to better manage radius and ulna fractures or pathology Level of evidence: Level 4 Keywords: radius, ulna, anatomy, osteology, radius of curvature, intramedullary design

Changes in canal width and angle in curved canals in the resin blocks: pro taper next versus one shape instruments

Objective: To compare the effect of OneShape and ProTaper Next file on the change in canal width and angle of curvature in simulated curved canal in resin blocks. Methods: The quasi-experimental study was conducted at the Aga Khan University, Karachi, from January to March 2018, and comprised endodontic resin blocks that had inbuilt curved canals. These were randomly divided into 2 equal groups and were subsequently prepared using OneShape in group A, and ProTaper Next rotary instrument in group B followed by staining with red and blue ink for comparison of pre- and post-operative images of canals. Standardised photographs were taken along with reference measuring scale. SPSS 22 was used for data analysis. Results: Of the 60 blocks, 30(50%) were in each of the two groups. The mean pre-instrumentation angle of curvature was 32.3±2.13 and 31.0+3.28 degrees for groups A and B. The mean degree of canal straightening post-intervention was 1.5+0.5 and 3.6+1.38 degrees in groups A and B (p<0.001). In terms of canal width changes, OneShape file removed more resin material from the canal walls compared to the ProTaper Next system (p<0.001). Conclusion: ProTaper Next file significantly altered the angle of curvature in the resin block compared to OneShape file, but the amount of material removed from the canal space was significantly higher with the OneShape file compared to ProTaper Next. Key Words: ProTaper Next, OneShape, Nickel-titanium Continuous...

Three-Dimensional Analysis of Root Anatomy and Root Canal Curvature in Mandibular Incisors Using Micro-Computed Tomography with Novel Software

Root canal treatment of mandibular incisor is difficult because of the narrow pulp space and apical curvature. The aim of this study was to measure the anatomical indicators of the mandibular incisors in Koreans using micro-computed tomography (MCT) with novel software (Kappa 2). The MCT-scanned data from 27 mandibular incisors were reconstructed and analyzed. For each canal, 3-dimensional (3D) surface models were re-sliced at 0.1 mm intervals perpendicular to the central axis of the root canal. Root canal width, dentine thickness, and direction and degree of root canal curvatures were measured automatically on each slice. Measurements were analyzed statistically with Bhapkar test, Friedman test, and Wilcoxon signed rank test. Labial and lingual dentine thicknesses were significantly larger than mesial and distal thicknesses (p < 0.001). The thinnest dentine was mainly located on the mesio-lingual side of the canals in the apical third. The mean narrowest and widest canal width in the apical sixth were 0.22 mm and 0.40 mm, respectively. The canal curvature abruptly increased in the apical 0.5-mm portion. MCT with novel software provided useful anatomical information for root canal instrumentation.

Morphometric study of hypoglossal canal of occipital bone in dry skulls of two states in southern nigeria

Background: It is observed that the morphologic and morphometric variability of the occipital bone structures may coexist in the same individual or among different subjects of the same or different populations and thus, a sound knowledge of the morphometry of this area can provide important benefits in determining safe surgical zones during surgical procedures. Aim: The present study was aimed at measuring the length (right and left) and width (right and left) of the hypoglossal canal among adult dry skulls of two states in southern Nigeria. Materials and Method: This study adopted the cross sectional study design. A total of eighty (80) hypoglossal canal; right and left were selected by simple random sampling and their length and width were measured with the aid of the digital vernier caliper. Results: The hypoglossal canal length on the right side was seen to be higher compared to the left length of the hypoglossal canal while the right hypoglossal canal width was seen to be higher compared to the left hypoglossal canal width and also observed differences between the right and left sides were statistically significant (P=0.01). Conclusion: There was a statistical significant difference with regard to hypoglossal canal length (right and left) and width (right and left) among the studied population. Bangladesh Journal of Medical Science Vol.19(4) 2020 p.670-672