Identification of Apical and Cervical Curvature Radius of Human Molars

<p>To determine the frequency of apical and cervical curvatures in human molars using the radius method and cone-beam computed tomography (CBCT) images. Four hundred images of mandibular and maxillary first and second molars were selected from a database of CBCT exams. The radius of curvature of curved root canals was measured using a circumcenter based on three mathematical points. Radii were classified according to the following scores: 0 - straight line; 1 - large radius (r>8 mm, mild curvature); 2 - intermediate radius (r>4 and r<8 mm, moderate curvature); and 3 - small radius (r≤4 mm, severe curvature). The frequency of curved root canals was analyzed according to root canal, root thirds, and coronal and sagittal planes, and assessed using the chi-square test (significance at α=0.05). Of the 1,200 evaluated root canals, 92.75% presented curved root canals in the apical third and 73.25% in the cervical third on coronal plane images; sagittal plane analysis yielded 89.75% of curved canals in the apical third and 77% in the cervical third. Root canals with a large radius were significantly more frequent when compared with the other categories, regardless of root third or plane. Most root canals of maxillary and mandibular first and second molars showed some degree of curvature in the apical and cervical thirds, regardless of the analyzed plane (coronal or sagittal).</p>

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Effects of Diode Laser, Gaseous Ozone, and Medical Dressings onEnterococcus faecalisBiofilms in the Root Canal Ex Vivo

BioMed Research International ◽

10.1155/2017/6321850 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Kerstin Bitter ◽

Alexander Vlassakidis ◽

Mediha Niepel ◽

Daniela Hoedke ◽

Julia Schulze ◽

...

Keyword(s):

Diode Laser ◽

Root Canal ◽

Ex Vivo ◽

Bacterial Reduction ◽

Chi Square ◽

Root Canals ◽

Planktonic Bacteria ◽

Gaseous Ozone ◽

Colony Forming Units ◽

Chi Square Test

The objective was to compare the antibacterial effects of adjunctive disinfection using diode laser and gaseous ozone compared to the medical dressings calcium hydroxide (Ca(OH)2) and chlorhexidine gel (CHX-Gel) onEnterococcus faecalisbiofilms in human root canals ex vivo. Root canals of 180 human extracted teeth were infected byE. faecalisand divided into 3 main groups (G): G1, control; G2, instrumentation and irrigation using 0.9% NaCl; G3, instrumentation and irrigation using 1% NaOCl. In each main group, the following treatments were applied: gaseous ozone, diode laser, and medical dressings of Ca(OH)2or CHX-Gel for 7 days (n=15). Reduction of colony forming units (CFUs) inside the root canal of planktons and frequencies of adherent bacteria after treatment were calculated. Bacterial reduction was significantly affected by the irrigation protocol (p<0.0005) and the disinfection method (p<0.0005), and a significant interaction between both factors could be observed (p<0.0005; ANOVA). In G3 (instrumentation using 1% NaOCl), no significant effect of disinfection methods could be demonstrated on planktonic bacteria (p=0.062; ANOVA) and frequencies of adherent bacteria (p>0.05; chi-square test). Instrumentation and irrigation using NaOCl combined with ozone or laser application resulted in comparable bacterial reduction onE. faecalisto the application of medical dressings.

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COMPARATIVE ANALYSIS OF MAMMALIAN SPERM MOTILITY

The Journal of Cell Biology ◽

10.1083/jcb.53.2.561 ◽

1972 ◽

Vol 53 (2) ◽

pp. 561-573 ◽

Cited By ~ 123

Author(s):

David M. Phillips

Keyword(s):

High Speed ◽

Mammalian Species ◽

Chinese Hamster ◽

Small Radius ◽

Radius Of Curvature ◽

Large Radius ◽

Cross Sectional ◽

Mammalian Sperm ◽

High Speed Cinematography ◽

Pass Through

Spermatozoa of several mammalian species were studied by means of high-speed cinematography and electron microscopy. Three types of motile patterns were observed in mouse spermatozoa. The first type involved an asymmetrical beat which seemed to propel the sperm in circular paths. The second type involved rotation of the sperm and appeared to allow them to maintain straight paths. In the third type of pattern, the sperm appeared to move by crawling on surfaces in a snakelike manner. Spermatozoa of rabbit and Chinese hamster also had an asymmetrical beat which sometimes caused them to swim in circles. In spite of the asymmetry of the beat, these spermatozoa were also able to swim in straight paths by rotating around a central axis as they swam. Spermatozoa of some species appeared very flexible; their flagella formed arcs with a very small radius of curvature as they beat. Spermatozoa of other species appeared very stiff, and their flagella formed arcs with a very large radius of curvature. The stiffness of the spermatozoan appeared to correlate positively with the cross-sectional area of the dense fibers. This suggests that the dense fibers may be stiff elastic elements. Opossum sperm become paired as they pass through the epididymis. Pairs of opossum spermatozoa beat in a coordinated, alternating manner.

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Analysis of anatomy and configuration of the canal system of the maxillary second premolar in the population of Bosnia and Herzegovina

Биомедицинска истраживања ◽

10.5937/bii2101009d ◽

2021 ◽

Vol 12 (1) ◽

pp. 9-18

Author(s):

Brankica Davidović ◽

Ljiljana Bjelović ◽

Igor Radović ◽

Bojana Davidović ◽

Svjetlana Janković ◽

...

Keyword(s):

Bosnia And Herzegovina ◽

Root Canal ◽

Statistical Significance ◽

Type I ◽

Canal System ◽

Chi Square ◽

Morphological Variations ◽

Root Canals ◽

Single Root ◽

Chi Square Test

Introduction. Successful endodontic treatment depends upon the clinician's knowledge and ability to recognize and diagnose the presence of anatomical and morphological variations of the root and canal system. The aim of this study was to establish the number of roots and root canal configurations of the maxillary second premolar in the population of Bosnia and Herzegovina. Methods. The study sample was comprised of 150 maxillary second premolar teeth extracted for orthodontic or prosthetic reasons. Endodontic drills were used for trepanation of cavum dentis, and the number and patency of each root canal were determined by Kexpander # 15. Then, the samples were decalcified, made transparent and colored, to enable 3D viewing of the canal system. Decalcified teeth were observed from two projections (clinical and approximal) and analyzed in detail with a magnifying glass under 3 × and 5 × magnification in order to determine the number of roots, number of canals, root canal configuration using Vertucci's classification and number of anastomoses between canals. Statistical significance was obtained using Chi-square test. Results. The results obtained by decalcification of the teeth showed that, by radiographic analysis from the clinical projection, all the teeth had a single root. While, by the analysis from the approximal projection, 94.0% had one, 6.0% two roots. From the approximal projection, 70.7% with a single root canal and 29.3% with two root canals are visualized. The most common type of root canal configuration in the maxillary second premolars was Type I in both clinical (87.9%) and approximal projection (40.7%). Conclusion. These results emphasize the importance of knowing the variations in root canal morphology, because excluding the possibility of morphological variations can lead to failure of endodontic therapy

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A comparative study of root canal shaping using protaper universal and protaper next rotary files in preclinical dental education

PeerJ ◽

10.7717/peerj.7419 ◽

2019 ◽

Vol 7 ◽

pp. e7419 ◽

Cited By ~ 1

Author(s):

Gül Çelik ◽

Feyza Özdemir Kısacık ◽

Emir Faruk Yılmaz ◽

Arife Mersinlioğlu ◽

İhsan Furkan Ertuğrul ◽

...

Keyword(s):

Root Canal ◽

Dental Students ◽

Chi Square ◽

Significance Level ◽

Root Canals ◽

Rotary Instruments ◽

Working Length ◽

Chi Square Test ◽

The Mean ◽

Canal Shaping

BackgroundDentistry has undergone an evolution in endodontics practice caused by the advancement of rotary techniques for root canal preparation and their subsequent incorporation into the teaching of dentistry undergraduates. This research aimed to evaluate the shaping ability of third-year dental students as their first experience in rotary instrumentation using ProTaper Universal (PTU) and ProTaper Next (PTN) (Dentsply Maillefer) rotary instruments in simulated curved canals.MethodsForty students instrumented 200 simulated canals with a 40° curvature in resin blocks according to the manufacturer’s instructions with PTU and 39 students and 195 canals with PTN files. The canals were prepared at a speed of 300 rpm using a 16:1 reduction hand-piece powered by an electric motor (Xsmart; Dentsply Maillefer). The final apical preparation was set to F2 for the PTU and X2 for the PTN group. The change in canal curvature was evaluated based on Schneider technique using the AutoCAD 2007 software on post-digital photographs. The incidence of instrument fracture and deformation, the incidence of ledge, the change in working length (WL), and the working time were noted. The data were analyzed with Student’st-test and Chi-Square test at a significance level of 0.05 using SPSS.ResultsPTN maintained the original canal curvature better, resulting in fewer fractures and ledges, and shaped the canals faster than the PTU (P < 0.05). The mean curves of the resin canals after the instrumentation for the PTU and PTN groups were 24.03° ± 3.14° and 25.64° ± 2.72°, respectively. Thirty-three (17.4%) PTU and 18 (9.3%) PTN files fractured (p < 0.05). Nine (4.5%) PTU and 2 (2.6%) PTN deformed (p > 0.05). The change in WL after instrumentation was 0.97 mm ± 0.95 mm in PTU and 0.96 mm ± 0.80 mm in PTN (p < 0.05). The mean times were 627 s ± 18 s for PTU and 379 s ± 18 s for PTN (p < 0.000).DiscussionPTN can be recommended in severely curved root canals in terms of maintenance of the original canal curvature, superior instrument fracture and fewer ledges. Even if training before preparation provides an acceptable level of canal shaping for preclinical students, the use of NiTi rotary instruments should be included in the undergraduate dental curriculum, contributing to an increase in the quality of root canal shaping and, consequently, to an improvement of the clinical experience of students.

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Variations in root canal morphology of the permanent mandibular first molar in Indian population- A CBCT study

IP International Journal of Maxillofacial Imaging ◽

10.18231/j.ijmi.2021.012 ◽

2021 ◽

Vol 7 (2) ◽

pp. 61-66

Author(s):

Vasavi Santosh ◽

Rhea Reji John ◽

Mandavi Waghmare ◽

Reema Manoj

Keyword(s):

Root Canal ◽

Indian Population ◽

Type I ◽

Chi Square ◽

Root Canals ◽

Gender And Age ◽

Chi Square Test ◽

Root Canal Morphology ◽

Mandibular First Molar ◽

Canal Morphology

The purpose of this study was to determine the variations in the number of canals and its morphology in permanent mandibular first molars using cone-beam computed tomography (CBCT) in a subset of Indian population. A total of 350 CBCT scans were collected and evaluated in all three orthogonal planes to determine the number of root canals and study their anatomic variations using Vertucci’s classification.: The total number of roots and root canals, the root canal configuration, the incidence, and the correlations between left- and right-side occurrences and between males and females were analysed. Statistically significant differences were evaluated using the chi-square test with SPSS 16.0 for Windows (SPSS, Chicago, IL), with significance set at p < 0.05.: The results of this study showed that predominantly, two thirds of the subjects had type VI mesial canal configuration and two-thirds had type I distal canal configuration. Also there was significant variance in the canal anatomy across gender and age of the subjects.: CBCT is a clinically useful tool in understanding the variations in root canal morphology, which guides in the assessment of the canal morphology aiding in successful root canal treatment.

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Study of Insertion Force and Deformation for Suturing With Precurved NiTi Guidewire

Journal of Biomechanical Engineering ◽

10.1115/1.4029311 ◽

2015 ◽

Vol 137 (4) ◽

Cited By ~ 2

Author(s):

Yancheng Wang ◽

Roland K. Chen ◽

Bruce L. Tai ◽

Kai Xu ◽

Albert J. Shih

Keyword(s):

Experimental Study ◽

Minimally Invasive ◽

Ex Vivo ◽

Nickel Titanium ◽

Small Radius ◽

Radius Of Curvature ◽

Large Radius ◽

Position Measurement ◽

Insertion Force ◽

Before And After

This research presents an experimental study evaluating stomach suturing using a precurved nickel–titanium (NiTi) guidewire for an endoscopic minimally invasive obesity treatment. Precise path planning is critical for accurate and effective suturing. A position measurement system utilizing a hand-held magnetic sensor was used to measure the shape of a precurved guidewire and to determine the radius of curvature before and after suturing. Ex vivo stomach suturing experiments using four different guidewire tip designs varying the radius of curvature and bevel angles were conducted. The changes in radius of curvature and suturing force during suturing were measured. A model was developed to predict the guidewire radius of curvature based on the measured suturing force. Results show that a small bevel angle and a large radius of curvature reduce the suturing force and the combination of small bevel angle and small radius of curvature can maintain the shape of guidewire for accurate suturing.

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Application of Conjugate Cam Design Software Platform in Die Cutting Platen Press Mechanism

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.127.207 ◽

2011 ◽

Vol 127 ◽

pp. 207-213

Author(s):

Xiang Dong Shi ◽

Shao Hua Shen ◽

Cheng Wen Chai

Keyword(s):

Small Radius ◽

Radius Of Curvature ◽

Curvature Radius ◽

Software Platform ◽

Excessive Pressure ◽

Pressure Angle ◽

Cam Design ◽

Design Software ◽

And Performance ◽

Design And Manufacture

The design of the conjugate cams was analyzed in this paper, and the calculation process of conjugate cams profile data to meet the pressure angle and the curvature radius was introduced in detail. With VB as the software platform, the curves data of the conjugate cams were designed and calculated, the curves were also displayed on the platform. Base on the designing platform, the motion parameter of the followers, such as displacement, velocity and acceleration, could be achieved and saved in the certain format. The parameterization design and motion analysis were also could be performed to help the designer to find the mistakes, such as the rotation difficulty caused by excessive pressure angle, the motion distortion and overcut during machining caused by small radius of curvature. So the mistakes could be corrected and the product developing cycle could be shortened. The system could accomplish the information transmission and information sharing among the subsystems and enhanced the integration and automation of the conjugate cam design and manufacture. It also could be taken as platform for designing, manufacturing and performance researching of the conjugate cams. Finally, the example of the moving platform die-cutting mechanism in an automatic die-cutting machine verified the usability and effectiveness of the software platform.

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Extra canal in permanent maxillary first molar in patients undergoing root canal treatment at a tertiary care dental hospital, Nepal

Journal of Kathmandu Medical College ◽

10.3126/jkmc.v10i1.38972 ◽

2021 ◽

Vol 10 (1) ◽

pp. 47-51

Author(s):

Archana Gharti ◽

Neera Joshi ◽

Kranti Prajapati ◽

Sharada Devi Wagle ◽

Suraj Shrestha

Keyword(s):

Root Canal ◽

Tertiary Care ◽

Cross Sectional Study ◽

Root Canal Treatment ◽

Chi Square ◽

Cross Sectional ◽

Root Canals ◽

Conservative Dentistry ◽

Ethical Approval ◽

Chi Square Test

Background: Permanent maxillary first molar normally has three root canals but it can have extra root canals for which several studies were done in many parts of the globe. However, this type of study to explore extra canal is lagging in the context of Nepal. Objectives: The objective was to determine the percentage of extra canal in permanent maxillary first molar in patients undergoing root canal treatment and to compare the same between male and female. Methods: The descriptive cross-sectional study was conducted in the department of conservative dentistry and endodontics of People’s Dental College and Hospital from 20th December 2019 to 20th December 2020 after receiving ethical approval from Nepal Health Research Council on 18th December 2019 (ERB protocol No 888/2019) . One hundred and eighty permanent maxillary first molar teeth without root canal calcification were enrolled. Convenient sampling was done. Access opening was done and all canal orifices were located and recorded. Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 22.0 with frequency table. Chi-square test was used for inferential statistics. Results: Out of 180 teeth, extra canals were present in 44(24.4%) having more numbers in male than in females. Extra canal was present in the mesiobuccal root. Conclusion: Extra canal in the permanent maxillary first molar is present in Nepalese population with greater number in male than in female. Thus, exploration of the pulp chamber in search of an extra canal is necessary to prevent failure of root canal treatment.

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Prevalence and Morphology of C-Shaped Canals: A CBCT Analysis in a Korean Population

Scanning ◽

10.1155/2021/9152004 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Sung Eun Yang ◽

Tae Yeon Lee ◽

Kyung Jae Kim

Keyword(s):

Wall Thickness ◽

Statistical Significance ◽

Anatomical Variations ◽

Korean Population ◽

Age Group ◽

Chi Square ◽

Root Canals ◽

Chi Square Test ◽

The Difference ◽

Cbct Analysis

This retrospective study of roots with C-shaped canals investigated their prevalence, configuration type, and lingual wall thickness, as well as the panoramic radiographic features of roots in permanent mandibular second molars confirmed to have C-shaped canals on cone-beam computed tomography (CBCT) in a Korean population. In total, 1884 CBCT images of mandibular second molars were examined by two endodontists to analyze the presence of C-shaped canals according to age and sex. The bilateral occurrence of C-shaped roots and their morphology on panoramic radiography were assessed and statistically analyzed using the chi-square test. The classification of Fan et al. was applied to categorize the configurations of C-shaped canals. The lingual wall thickness was calculated in the mesial, middle, and distal areas at the orifice and at 5 mm from the apex. The Mann–Whitney U test was used to analyze the mean difference of lingual wall thickness between the apex and orifice level. A P value of 0.05 was considered to indicate statistical significance in the statistical analyses. Of 2508 mandibular second molars, 924 (36.8%) had C-shaped root canals. The prevalence was significantly lower in the over 61 age group (24.08%) than in the 21–30-year age group (40.02%) and was higher in women (42.32%). Most cases were bilateral (85.9%). The C1 type was the most common (35.3%). The prevalence of C1 type canals decreased, while that of C3b type canals increased with age. In 75.2% of teeth having C-shaped root canals on CBCT, fused roots were observed on panoramic views. The difference in the lingual wall thickness at the orifice and 5 mm from the apex was significant in the middle area in all configurations of C-shaped root canals. When performing nonsurgical or surgical endodontic procedures of the mandibular second molars, clinicians should consider age, sex, ethnicity, and anatomical variations.

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Root Anatomy and Root Canal Configuration of Human Permanent Mandibular Premolars: A Systematic Review

Anatomy Research International ◽

10.1155/2013/254250 ◽

2013 ◽

Vol 2013 ◽

pp. 1-14 ◽

Cited By ~ 9

Author(s):

Jojo Kottoor ◽

Denzil Albuquerque ◽

Natanasabapathy Velmurugan ◽

Jacob Kuruvilla

Keyword(s):

Systematic Review ◽

Anatomic Variation ◽

Case Reports ◽

Statistical Significance ◽

Middle Eastern ◽

Root Anatomy ◽

Chi Square ◽

Root Canals ◽

Pubmed Database ◽

Chi Square Test

Introduction. Mandibular premolars have been reported with complex anatomical aberrations, making them one of the most difficult teeth to manage endodontically. Methodology. An exhaustive search was undertaken to identify associated anatomic studies of mandibular premolars through MEDLINE/PubMed database using keywords, and a systematic review of the relevant articles was performed. Chi-square test with Yates correction was performed to assess the statistical significance of any anatomic variations between ethnicities and within populations of the same ethnicity. Documented case reports of variations in mandibular premolar anatomy were also identified and reviewed. Results. Thirty-six anatomic studies were analyzed which included 12,752 first premolars and nineteen studies assessing 6646 second premolars. A significant variation in the number of roots, root canals, and apical foramen was observed between Caucasian, Indian, Mongoloid, and Middle Eastern ethnicities.The most common anatomic variation was C-shaped canals in mandibular first premolars with highest incidence in Mongoloid populations (upto 24%) while dens invaginatus was the most common developmental anomaly. Conclusions. A systematic review of mandibular premolars based on ethnicity and geographic clusters offered enhanced analysis of the prevalence of number of roots and canals, their canal configuration, and other related anatomy.

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