The effect of rotary instrumentation on dentin thickness in the danger zone of the MB2 canal of maxillary first molars

2021 ◽  
Author(s):  
Jeffrey D. Heyse ◽  
Ronald Ordinola‐Zapata ◽  
Laurence Gaalaas ◽  
Scott B. McClanahan
Keyword(s):  
Danger Zone ◽  
Dentin Thickness

scholarly journals Validation of cone beam computed tomography as a clinical imaging method for dentin thickness measurement in the danger zone of mandibular molars

2018 ◽  
Vol 23 (1) ◽  
Author(s):  
Fernanda Gomez Corrêa ◽  
Claudia Bohrer Flores ◽  
Flávia Kolling Marquezan ◽  
Gabriela Salatino Liedke ◽  
Gustavo Nogara Dotto ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Thickness Measurement ◽  
Cone Beam ◽  
Imaging Method ◽  
Danger Zone ◽  
Mean Values ◽  
Mandibular Molars ◽  
Before And After ◽  
Dentin Thickness

Objective: to verify the accuracy of cone beam computedtomography (CBCT) for measuring dentin thicknessin the danger zone of mandibular molars in order to validatethis method to be used as a clinical auxiliary. Materialsand method: dentin thickness of the distal wall ofmesial canals was measured at 2 mm of furcation areain ten mandibular molars before and after preparation ofcervical and middle thirds. CBCT (0.25 mm voxel size)and stereomicroscopy images were acquired twice foreach sample. CBCT axial images and stereomicroscopeimages were evaluated by a calibrated examiner. Statisticalanalysis was performed using Mann-Whitney testin order to investigate whether CBCT images providedtrusted values. Results: mean values of initial (1.23 versus1.24 mm) and final measurements (0.88 versus 0.87mm) obtained with, respectively, CBCT and stereomicroscopemethods did not show statistical differences(P > 0.5). Conclusion: CBCT images provide high accuracyfor measuring dentin thickness in the danger zoneof mandibular molars.Keywords: Cone beam computed tomography. Endodontics.Root canal preparation.

scholarly journals COMPARATIVE EVALUATION OF RADICULAR DENTINE THICKNESS IN DANGER ZONE OF MANDIBULAR FIRST MOLAR AFTER INSTRUMENTATION WITH TWO DIFFERENT ROTARY SYSTEMS USING CBCT - AN INVITRO STUDY

2020 ◽  
Vol 4 (8) ◽  
Author(s):  
Ambika Sigadam ◽  
Kalyan Satish R ◽  
Girija. S. Sajjan ◽  
Madhu Varma K ◽  
Kolla Vishal Babu ◽  
...  
Keyword(s):  
Comparative Evaluation ◽  
File System ◽  
File Systems ◽  
Danger Zone ◽  
Single File ◽  
Significant Difference ◽  
Before And After ◽  
Distal Surface ◽  
Mandibular First Molar ◽  
Dentin Thickness

Introduction: The mandibular first molar poses a series of anatomic challenges such as multiple canals, isthmuses, lateral canals, and apical ramifications. Additionally, the distal surface of mesial root presents a thin zone, which is 4-6 mm cervical to canal orifice with a thin area of dentin termed as “danger zone,” as it increases the risk of perforation of furcal dentin during mechanical instrumentation. Aim: To measure the amount of the dentin removed after biomechanical preparation with XP-Endoshaper and Neoendo flex files in the danger zone of the mandibular first molar using CBCT. Methodology: Twenty-four mandibular first molars, the mesial roots of which presented a curvature of 20-30 degrees, were selected using the Schneider method. Samples were instrumented with Neoendo rotary file system (n=12) and XP-Endoshaper rotary single file system (n=12). The samples were scanned using CBCT before and after instrumentation. The analyzed parameter includes the remaining dentin thickness at the danger zone of the mandibular 1st molar. The obtained data were subjected to statistical analysis. Results: There was no significant difference in remaining dentine thickness between the two rotary systems (p > 0.05). Conclusion: XP-Endoshaper revealed better results than Neoendo rotary files. However, both rotary file systems showed no significant difference in the remaining dentin thickness in the danger zone of the mandibular first molar. Keywords: Danger zone, Remaining dentine thickness, XP EndoShaper, NeoEndo, CBCT.

Teen Danger Zone: Teens at Risk

2005 ◽  
Keyword(s):  
At Risk ◽  
Danger Zone

Danger, zone de non-droit !

1990 ◽  
Vol 1128 (1) ◽  
pp. 21-24
Author(s):  
Jean-Louis Rageul
Keyword(s):  
Danger Zone

Reflections on the Meaning of Study Abroad

1995 ◽  
Vol 1 ◽  
pp. 96-103
Author(s):  
Elizabeth Shannon
Keyword(s):  
Study Abroad ◽  
Nursery School ◽  
Multiple Identities ◽  
Danger Zone ◽  
Host Family ◽  
The People ◽  
Life Itself ◽  
The Moment ◽  
First Time ◽  
The Stranger

Study abroad begins long before students leave their own shores. The moment that children enter daycare, nursery school, or kindergarten for the first time, they are in foreign territory, and all their antennae are out, testing, absorbing, learning. They begin to develop the first of their many multiple identities. They are no longer "Johnny" or "Sarah" whom everyone knows and loves at home, but Johnny or Sarah whom no one knows nor initially cares about, and they have to figure out what kind of a new identity they will develop so the danger zone becomes as safe as home.  Leaving familiar surroundings- the sounds, smells, safety, and food of home- and realizing, quite abruptly, that they must learn to adapt to the demands and needs of strangers, is the first and the most challenging "trip abroad" they will ever take. They will use the same set of skills, more mature, more polished (we hope) when they arrive on a foreign campus and move in with a host family or into an international dormitory.  Learning to make the journey with ease, whether it is on the first day of school or the day a plane drops one in a foreign field, is a necessary accomplishment. We have to make friends out of our peers; we have to gain the respect of our teachers; we have to develop curiosity and concern about the people around us. The stranger they seem, the more there is to learn. To fear diversity is to fear life itself. As the world becomes smaller and more integrated, the more crucial this accomplishment grows. 

Danger zone for screw placement in minimally invasive plate osteosynthesis (MIPO) of diaphyseal fractures of forearm: a cadaveric study

2021 ◽  
Author(s):  
Apipop Kritsaneephaiboon ◽  
Watit Wuttimanop ◽  
Surasak Jitprapaikulsarn ◽  
Pornpanit Dissaneewate ◽  
Chulin Chewakidakarn ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Plate Osteosynthesis ◽  
Cadaveric Study ◽  
Screw Placement ◽  
Minimally Invasive Plate Osteosynthesis ◽  
Danger Zone ◽  
Diaphyseal Fractures

scholarly journals Empirical Research on Climate Warming Risks for Forest Fires: A Case Study of Grade I Forest Fire Danger Zone, Sichuan Province, China

2021 ◽  
Vol 13 (14) ◽  
pp. 7773
Author(s):  
San Wang ◽  
Hongli Li ◽  
Shukui Niu
Keyword(s):  
Wind Speed ◽  
Forest Fire ◽  
Climate Warming ◽  
Forest Fires ◽  
Meteorological Factors ◽  
Sichuan Province ◽  
Danger Zone ◽  
Climatic Regions ◽  
Area Burned ◽  
Forest Fire Danger

The Sichuan province is a key area for forest and grassland fire prevention in China. Forest resources contribute significantly not only to the biological gene pool in the mid latitudes but also in reducing the concentration of greenhouse gases and slowing down global warming. To study and forecast forest fire change trends in a grade I forest fire danger zone in the Sichuan province under climate change, the dynamic impacts of meteorological factors on forest fires in different climatic regions were explored and a model between them was established by using an integral regression in this study. The results showed that the dominant factor behind the area burned was wind speed in three climatic regions, particularly in Ganzi and A’ba with plateau climates. In Ganzi and A’ba, precipitation was mainly responsible for controlling the number of forest fires while it was mainly affected by temperature in Panzhihua and Liangshan with semi-humid subtropical mountain climates. Moreover, the synergistic effect of temperature, precipitation and wind speed was responsible in basin mid-subtropical humid climates with Chengdu as the center and the influence of temperature was slightly higher. The differential forest fire response to meteorological factors was observed in different climatic regions but there was some regularity. The influence of monthly precipitation in the autumn on the area burned in each climatic region was more significant than in other seasons, which verified the hypothesis of a precipitation lag effect. Climate warming and the combined impact of warming effects may lead to more frequent and severe fires.

Lessons Learned From a Chlorine Gas Leakage in Dezful City, Iran

2020 ◽  
pp. 1-7
Author(s):  
Gholamreza Masoumi ◽  
Mohammad Maniey ◽  
Hamidreza Aghababaeian ◽  
Abbas Ostadtaghizadeh ◽  
Ladan Araghi Ahvazi
Keyword(s):  
Warning System ◽  
Lessons Learned ◽  
Chemical Safety ◽  
Danger Zone ◽  
Khuzestan Province ◽  
Gas Leakage ◽  
Intervention Plan ◽  
Chlorine Gas ◽  
Lack Of Control ◽  
Lack Of Knowledge

Abstract Dezful is the capital of Dezful County, a city in Khuzestan Province, Iran. On August 12, 2017, after a chlorine gas leakage in Dezful, more than 475 people were affected by chlorine gas, and they all suffered from respiratory complications. A lot of problems were encountered in the preparation of the relief forces and organization of the blueprint on how to respond to the incident, such as lack of knowledge on establishment of danger zone, lack of warning system, lack of proper triage and absence of decontamination plans, lack of special chemical safety outfit and respiratory equipment for rescuers, lack of instructions for proper handling, lack of knowledge in dealing with this type of disaster, and inappropriate evacuation skills and failure to cordon off and insure the location of the incident. Although the initial measures to arrest this crisis was performed based on the health system’s instructions of the country with regard to all the possible risks, lack of a comprehensive inter-organizational program and prevention plans, lack of control plans, lack of adequate preparation and response to chemical poisoning, lack of foresight, lack of a risk plan, and lack of an intervention plan for these incidents were the reasons for the damages and problems encountered after the crisis.

Remaining root dentin thickness in mesiobuccal canals of maxillary first molars after attempted removal of broken instrument fragments

2015 ◽  
Vol 41 (3) ◽  
pp. 122-127 ◽  
Author(s):  
Yuan Gao ◽  
Ya Shen ◽  
Xuedong Zhou ◽  
Markus Haapasalo
Keyword(s):  
Root Dentin ◽  
Dentin Thickness
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