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Marco Aurelio Versiani - One of the best experts on this subject based on the ideXlab platform.
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Root groove depth and inter-orifice canal distance as anatomical predictive factors for Danger Zone in the mesial root of mandibular first molars
Clinical Oral Investigations, 2020Co-Authors: Gustavo De-deus, Felipe Goncalves Belladonna, Evaldo Almeida Rodrigues, Jong-ki Lee, J. Kim, Emmanuel João Nogueira Leal Silva, Daniele Moreira Cavalcante, Marco Simões-carvalho, Diogo Da Silva Oliveira, Marco Aurelio VersianiAbstract:Objectives This study evaluated the Danger Zone (DZ) in mesial roots of mandibular molars and the correlation between anatomical references of the DZ and some anatomical landmarks including tooth/root length, depth of mesial and distal grooves, and inter-canal orifices distance. Material and methods Twenty-eight mesial roots of mandibular molars with 2 independent canals were scanned and divided into 2 groups according to root length. The anatomical landmarks were correlated (Pearson or Spearman coefficients) with root level, thickness, and position of the DZ and also compared (independent samples t or Mann-Whitney tests) between the 2 groups at α = 5%. Results No statistical difference was observed between groups regarding DZ parameters and depth of mesial and distal grooves ( P > 0.05). Orifice distance in group 2 (4.49 ± 0.75 mm) was significantly greater than group 1 (3.76 ± 0.89 mm) ( P < 0.05). Significant correlations ( P < 0.05) were found between (i) DZ level and root/tooth length ( r = 0.54 and 0.49, respectively), (ii) DZ thickness and distal groove depth ( r = − 0.45), and orifice distance ( r = 0.38), and (iii) DZ position and depth of mesial ( r = 0.39) and distal ( r = 0.40) grooves. Other variables such as root length and distal groove depth ( r = 0.28), and orifice distance and mesial groove depth ( r = 0.36) were also correlated ( P < 0.05). Conclusions The length of tooth/root, the distance of canal orifices, and the depth of mesial/distal grooves of mesial roots of mandibular molars might be predictive factors for the root level, position, and thickness of the DZ. Clinical relevance The length, distance of mesial canal orifices, and the depth of mesial and distal grooves of the mesial roots of mandibular molars might be moderate predictive factors for the root level, position, and thickness of the DZ.
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Root groove depth and inter-orifice canal distance as anatomical predictive factors for Danger Zone in the mesial root of mandibular first molars.
Clinical oral investigations, 2020Co-Authors: Gustavo De-deus, Evaldo Rodrigues, Felipe Goncalves Belladonna, D M Cavalcante, Diogo Da Silva Oliveira, M. Simões‐carvalho, Jong-ki Lee, Emmanuel João Nogueira Leal Silva, Jeong-il Kim, Marco Aurelio VersianiAbstract:This study evaluated the Danger Zone (DZ) in mesial roots of mandibular molars and the correlation between anatomical references of the DZ and some anatomical landmarks including tooth/root length, depth of mesial and distal grooves, and inter-canal orifices distance. Twenty-eight mesial roots of mandibular molars with 2 independent canals were scanned and divided into 2 groups according to root length. The anatomical landmarks were correlated (Pearson or Spearman coefficients) with root level, thickness, and position of the DZ and also compared (independent samples t or Mann-Whitney tests) between the 2 groups at α = 5%. No statistical difference was observed between groups regarding DZ parameters and depth of mesial and distal grooves (P > 0.05). Orifice distance in group 2 (4.49 ± 0.75 mm) was significantly greater than group 1 (3.76 ± 0.89 mm) (P < 0.05). Significant correlations (P < 0.05) were found between (i) DZ level and root/tooth length (r = 0.54 and 0.49, respectively), (ii) DZ thickness and distal groove depth (r = - 0.45), and orifice distance (r = 0.38), and (iii) DZ position and depth of mesial (r = 0.39) and distal (r = 0.40) grooves. Other variables such as root length and distal groove depth (r = 0.28), and orifice distance and mesial groove depth (r = 0.36) were also correlated (P < 0.05). The length of tooth/root, the distance of canal orifices, and the depth of mesial/distal grooves of mesial roots of mandibular molars might be predictive factors for the root level, position, and thickness of the DZ. The length, distance of mesial canal orifices, and the depth of mesial and distal grooves of the mesial roots of mandibular molars might be moderate predictive factors for the root level, position, and thickness of the DZ.
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anatomical Danger Zone reconsidered a micro ct study on dentine thickness in mandibular molars
International Endodontic Journal, 2019Co-Authors: Gustavo Dedeus, Marco Aurelio Versiani, Evaldo Rodrigues, Felipe Goncalves Belladonna, M Simoescarvalho, D M Cavalcante, Diogo Da Silva Oliveira, Erick Miranda Souza, K A Giorgi, R T LopesAbstract:Aim To investigate the smallest dentine thickness in mesial canals of mandibular molars along the cervical and middle thirds of the root by means of a micro-computed tomographic (micro-CT) technology and digital image analysis. Methodology Fifty mesial roots of mandibular molars having two independent canals (mesiobuccal and mesiolingual), in the coronal and middle levels, were selected and scanned in a micro-CT device. After reconstruction procedures, approximately 468 slices per root covering the 7 mm below the furcation area of the mesial root were analysed to measure the smallest dentine thickness (Danger Zone [DZ]) in each slice from both distal and mesial regions of the mesial canals by an automatic segmentation process. Results The DZ values in the mesiobuccal canals varied from 0.67 to 1.93 mm, with an average of 1.13 ± 0.21 mm. For the mesiolingual canals, the DZ varied from 0.77 to 1.89 mm with an average of 1.10 ± 0.21 mm. There was no correspondence in the DZ between the mesiobuccal and mesiolingual canals at the same cross-sectional level in 71% of the specimens. Moreover, the smallest dentine thickness was towards the mesial region of the roots in 22% and 18% of the mesiolingual and mesiobuccal canals, respectively. (Figs 1 and 2 CONCLUSIONS: The smallest dentine thickness was on the mesial plane of the roots in about 40% of the canals. The vertical location of the DZ in relation to the furcation area was in the middle third of the root.
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Anatomical Danger Zone reconsidered: a micro-CT study on dentine thickness in mandibular molars.
International endodontic journal, 2019Co-Authors: Gustavo De-deus, Marco Aurelio Versiani, Evaldo Rodrigues, Felipe Goncalves Belladonna, D M Cavalcante, Diogo Da Silva Oliveira, Erick Miranda Souza, K A Giorgi, M. Simões‐carvalho, R T LopesAbstract:To investigate the smallest dentine thickness in mesial canals of mandibular molars along the cervical and middle thirds of the root by means of a micro-computed tomographic (micro-CT) technology and digital image analysis. Fifty mesial roots of mandibular molars having two independent canals (mesiobuccal and mesiolingual), in the coronal and middle levels, were selected and scanned in a micro-CT device. After reconstruction procedures, approximately 468 slices per root covering the 7 mm below the furcation area of the mesial root were analysed to measure the smallest dentine thickness (Danger Zone [DZ]) in each slice from both distal and mesial regions of the mesial canals by an automatic segmentation process. The DZ values in the mesiobuccal canals varied from 0.67 to 1.93 mm, with an average of 1.13 ± 0.21 mm. For the mesiolingual canals, the DZ varied from 0.77 to 1.89 mm with an average of 1.10 ± 0.21 mm. There was no correspondence in the DZ between the mesiobuccal and mesiolingual canals at the same cross-sectional level in 71% of the specimens. Moreover, the smallest dentine thickness was towards the mesial region of the roots in 22% and 18% of the mesiolingual and mesiobuccal canals, respectively. (Figs 1 and 2 CONCLUSIONS: The smallest dentine thickness was on the mesial plane of the roots in about 40% of the canals. The vertical location of the DZ in relation to the furcation area was in the middle third of the root. © 2019 International Endodontic Journal. Published by John Wiley & Sons Ltd.
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micro ct analysis of Danger Zone thickness in the mesiobuccal roots of maxillary first molars
International Endodontic Journal, 2019Co-Authors: Ronald Ordinolazapata, Jorge N R Martins, Marco Aurelio Versiani, Clovis Monteiro BramanteAbstract:AIM To evaluate dentine thickness from both distal ('Danger Zone') and mesial ('safety Zone') aspects of the MB1 and MB2 canals of maxillary first molars at the furcation level using micro-CT imaging. METHODOLOGY One hundred maxillary first molars with two canals in the MB root were selected from a Brazilian subpopulation and scanned at a resolution of 19.6 μm in a micro-CT device. From each specimen, two axial cross-sectioned images were selected at 2 and 3 mm apical to the furcation level of the MB root and evaluated for the smallest dentinal thickness. Measurements were made from the outer perimeter of the MB1 and MB2 canals towards the external root surface from both distal (Danger Zone) and mesial (safety Zone) aspects of the root. The influence of an isthmus was also considered in the analysis, and samples were classified according to the presence or absence of an isthmus in the axial sections. Non-parametric Wilcoxon signed-rank tests were used to compare dentinal thickness between MB1 and MB2 canals with a significant level set at 5%. Colour-coded 3D models of dentine thickness throughout the MB root were created and evaluated qualitatively. RESULTS At both levels, median dentine thickness of the MB2 canal was significantly lower in both distal and mesial aspects of the root in comparison with the MB1 canal (P < 0.01). The presence of an isthmus was not a variable that influenced dentinal thickness. Colour-coded models indicated that dentine thickness was dependent on the cross-sectional shape of the MB root. At least 50% of the sample had <1 mm of dentine thickness at the Danger Zone of the MB2 canal. CONCLUSIONS Danger Zones in the MB roots of maxillary first molars were not symmetrical. MB2 canals had less dentine thickness on both aspects of the root compared to the MB1 canal.
Gustavo De-deus - One of the best experts on this subject based on the ideXlab platform.
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Root groove depth and inter-orifice canal distance as anatomical predictive factors for Danger Zone in the mesial root of mandibular first molars
Clinical Oral Investigations, 2020Co-Authors: Gustavo De-deus, Felipe Goncalves Belladonna, Evaldo Almeida Rodrigues, Jong-ki Lee, J. Kim, Emmanuel João Nogueira Leal Silva, Daniele Moreira Cavalcante, Marco Simões-carvalho, Diogo Da Silva Oliveira, Marco Aurelio VersianiAbstract:Objectives This study evaluated the Danger Zone (DZ) in mesial roots of mandibular molars and the correlation between anatomical references of the DZ and some anatomical landmarks including tooth/root length, depth of mesial and distal grooves, and inter-canal orifices distance. Material and methods Twenty-eight mesial roots of mandibular molars with 2 independent canals were scanned and divided into 2 groups according to root length. The anatomical landmarks were correlated (Pearson or Spearman coefficients) with root level, thickness, and position of the DZ and also compared (independent samples t or Mann-Whitney tests) between the 2 groups at α = 5%. Results No statistical difference was observed between groups regarding DZ parameters and depth of mesial and distal grooves ( P > 0.05). Orifice distance in group 2 (4.49 ± 0.75 mm) was significantly greater than group 1 (3.76 ± 0.89 mm) ( P < 0.05). Significant correlations ( P < 0.05) were found between (i) DZ level and root/tooth length ( r = 0.54 and 0.49, respectively), (ii) DZ thickness and distal groove depth ( r = − 0.45), and orifice distance ( r = 0.38), and (iii) DZ position and depth of mesial ( r = 0.39) and distal ( r = 0.40) grooves. Other variables such as root length and distal groove depth ( r = 0.28), and orifice distance and mesial groove depth ( r = 0.36) were also correlated ( P < 0.05). Conclusions The length of tooth/root, the distance of canal orifices, and the depth of mesial/distal grooves of mesial roots of mandibular molars might be predictive factors for the root level, position, and thickness of the DZ. Clinical relevance The length, distance of mesial canal orifices, and the depth of mesial and distal grooves of the mesial roots of mandibular molars might be moderate predictive factors for the root level, position, and thickness of the DZ.
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Root groove depth and inter-orifice canal distance as anatomical predictive factors for Danger Zone in the mesial root of mandibular first molars.
Clinical oral investigations, 2020Co-Authors: Gustavo De-deus, Evaldo Rodrigues, Felipe Goncalves Belladonna, D M Cavalcante, Diogo Da Silva Oliveira, M. Simões‐carvalho, Jong-ki Lee, Emmanuel João Nogueira Leal Silva, Jeong-il Kim, Marco Aurelio VersianiAbstract:This study evaluated the Danger Zone (DZ) in mesial roots of mandibular molars and the correlation between anatomical references of the DZ and some anatomical landmarks including tooth/root length, depth of mesial and distal grooves, and inter-canal orifices distance. Twenty-eight mesial roots of mandibular molars with 2 independent canals were scanned and divided into 2 groups according to root length. The anatomical landmarks were correlated (Pearson or Spearman coefficients) with root level, thickness, and position of the DZ and also compared (independent samples t or Mann-Whitney tests) between the 2 groups at α = 5%. No statistical difference was observed between groups regarding DZ parameters and depth of mesial and distal grooves (P > 0.05). Orifice distance in group 2 (4.49 ± 0.75 mm) was significantly greater than group 1 (3.76 ± 0.89 mm) (P < 0.05). Significant correlations (P < 0.05) were found between (i) DZ level and root/tooth length (r = 0.54 and 0.49, respectively), (ii) DZ thickness and distal groove depth (r = - 0.45), and orifice distance (r = 0.38), and (iii) DZ position and depth of mesial (r = 0.39) and distal (r = 0.40) grooves. Other variables such as root length and distal groove depth (r = 0.28), and orifice distance and mesial groove depth (r = 0.36) were also correlated (P < 0.05). The length of tooth/root, the distance of canal orifices, and the depth of mesial/distal grooves of mesial roots of mandibular molars might be predictive factors for the root level, position, and thickness of the DZ. The length, distance of mesial canal orifices, and the depth of mesial and distal grooves of the mesial roots of mandibular molars might be moderate predictive factors for the root level, position, and thickness of the DZ.
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Anatomical Danger Zone reconsidered: a micro-CT study on dentine thickness in mandibular molars.
International endodontic journal, 2019Co-Authors: Gustavo De-deus, Marco Aurelio Versiani, Evaldo Rodrigues, Felipe Goncalves Belladonna, D M Cavalcante, Diogo Da Silva Oliveira, Erick Miranda Souza, K A Giorgi, M. Simões‐carvalho, R T LopesAbstract:To investigate the smallest dentine thickness in mesial canals of mandibular molars along the cervical and middle thirds of the root by means of a micro-computed tomographic (micro-CT) technology and digital image analysis. Fifty mesial roots of mandibular molars having two independent canals (mesiobuccal and mesiolingual), in the coronal and middle levels, were selected and scanned in a micro-CT device. After reconstruction procedures, approximately 468 slices per root covering the 7 mm below the furcation area of the mesial root were analysed to measure the smallest dentine thickness (Danger Zone [DZ]) in each slice from both distal and mesial regions of the mesial canals by an automatic segmentation process. The DZ values in the mesiobuccal canals varied from 0.67 to 1.93 mm, with an average of 1.13 ± 0.21 mm. For the mesiolingual canals, the DZ varied from 0.77 to 1.89 mm with an average of 1.10 ± 0.21 mm. There was no correspondence in the DZ between the mesiobuccal and mesiolingual canals at the same cross-sectional level in 71% of the specimens. Moreover, the smallest dentine thickness was towards the mesial region of the roots in 22% and 18% of the mesiolingual and mesiobuccal canals, respectively. (Figs 1 and 2 CONCLUSIONS: The smallest dentine thickness was on the mesial plane of the roots in about 40% of the canals. The vertical location of the DZ in relation to the furcation area was in the middle third of the root. © 2019 International Endodontic Journal. Published by John Wiley & Sons Ltd.
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The Effect of Larger Apical Preparations in the Danger Zone of Lower Molars Prepared Using the Mtwo and Reciproc Systems
Journal of endodontics, 2014Co-Authors: Arnaldo Sant'anna Júnior, Clovis Monteiro Bramante, Ronald Ordinola-zapata, Gustavo De-deus, Bruno Cavalini Cavenago, Marco Antonio Hungaro DuarteAbstract:Abstract Introduction The aim of this study was to evaluate the effects of large apical preparations in the Danger Zones of the mesial root canals of mandibular molars instrumented with the Mtwo and Reciproc systems (VDW, Munich, Germany) until reaching apical diameters of 0.25 and 0.40 mm. Methods Twelve mandibular molars, the mesial roots of which presented distinct foramens and similar anatomies, were selected using micro–computed tomographic scanning. Mtwo and Reciproc instruments were used to shape the mesiobuccal or mesiolingual canals. The mesial canals were scanned before and after the use of 0.25- and 0.40-mm Mtwo and Reciproc instruments. The analyzed parameters included the root canal volume and remaining dentin thickness at 5 different levels. The obtained data were subjected to paired analysis of variance and Tukey or Friedman and Dunn tests for intragroup analysis and the Mann-Whitney U test for comparison between the mesial and distal walls. Results There were no significant differences between the mesial and distal dentin thickness for the points analyzed with both instrumentation techniques (P > .05). The volumetric analysis revealed a significant difference (P Conclusions Both systems performed similarly for the preparation of curved root canals with separate apical foramens. The increase of the root canal preparation with the 0.40-mm instrument significantly increased the root canal volume at the apical third without significantly reducing the dentin thickness in the Danger Zone for both instrument systems.
Clovis Monteiro Bramante - One of the best experts on this subject based on the ideXlab platform.
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micro ct analysis of Danger Zone thickness in the mesiobuccal roots of maxillary first molars
International Endodontic Journal, 2019Co-Authors: Ronald Ordinolazapata, Jorge N R Martins, Marco Aurelio Versiani, Clovis Monteiro BramanteAbstract:AIM To evaluate dentine thickness from both distal ('Danger Zone') and mesial ('safety Zone') aspects of the MB1 and MB2 canals of maxillary first molars at the furcation level using micro-CT imaging. METHODOLOGY One hundred maxillary first molars with two canals in the MB root were selected from a Brazilian subpopulation and scanned at a resolution of 19.6 μm in a micro-CT device. From each specimen, two axial cross-sectioned images were selected at 2 and 3 mm apical to the furcation level of the MB root and evaluated for the smallest dentinal thickness. Measurements were made from the outer perimeter of the MB1 and MB2 canals towards the external root surface from both distal (Danger Zone) and mesial (safety Zone) aspects of the root. The influence of an isthmus was also considered in the analysis, and samples were classified according to the presence or absence of an isthmus in the axial sections. Non-parametric Wilcoxon signed-rank tests were used to compare dentinal thickness between MB1 and MB2 canals with a significant level set at 5%. Colour-coded 3D models of dentine thickness throughout the MB root were created and evaluated qualitatively. RESULTS At both levels, median dentine thickness of the MB2 canal was significantly lower in both distal and mesial aspects of the root in comparison with the MB1 canal (P < 0.01). The presence of an isthmus was not a variable that influenced dentinal thickness. Colour-coded models indicated that dentine thickness was dependent on the cross-sectional shape of the MB root. At least 50% of the sample had <1 mm of dentine thickness at the Danger Zone of the MB2 canal. CONCLUSIONS Danger Zones in the MB roots of maxillary first molars were not symmetrical. MB2 canals had less dentine thickness on both aspects of the root compared to the MB1 canal.
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Micro-CT analysis of Danger Zone thickness in the mesiobuccal roots of maxillary first molars.
International endodontic journal, 2018Co-Authors: Ronald Ordinola-zapata, Jorge N R Martins, Marco Aurelio Versiani, Clovis Monteiro BramanteAbstract:To evaluate dentine thickness from both distal ('Danger Zone') and mesial ('safety Zone') aspects of the MB1 and MB2 canals of maxillary first molars at the furcation level using micro-CT imaging. One hundred maxillary first molars with two canals in the MB root were selected from a Brazilian subpopulation and scanned at a resolution of 19.6 μm in a micro-CT device. From each specimen, two axial cross-sectioned images were selected at 2 and 3 mm apical to the furcation level of the MB root and evaluated for the smallest dentinal thickness. Measurements were made from the outer perimeter of the MB1 and MB2 canals towards the external root surface from both distal (Danger Zone) and mesial (safety Zone) aspects of the root. The influence of an isthmus was also considered in the analysis, and samples were classified according to the presence or absence of an isthmus in the axial sections. Non-parametric Wilcoxon signed-rank tests were used to compare dentinal thickness between MB1 and MB2 canals with a significant level set at 5%. Colour-coded 3D models of dentine thickness throughout the MB root were created and evaluated qualitatively. At both levels, median dentine thickness of the MB2 canal was significantly lower in both distal and mesial aspects of the root in comparison with the MB1 canal (P < 0.01). The presence of an isthmus was not a variable that influenced dentinal thickness. Colour-coded models indicated that dentine thickness was dependent on the cross-sectional shape of the MB root. At least 50% of the sample had <1 mm of dentine thickness at the Danger Zone of the MB2 canal. Danger Zones in the MB roots of maxillary first molars were not symmetrical. MB2 canals had less dentine thickness on both aspects of the root compared to the MB1 canal. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.
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The Effect of Larger Apical Preparations in the Danger Zone of Lower Molars Prepared Using the Mtwo and Reciproc Systems
Journal of endodontics, 2014Co-Authors: Arnaldo Sant'anna Júnior, Clovis Monteiro Bramante, Ronald Ordinola-zapata, Gustavo De-deus, Bruno Cavalini Cavenago, Marco Antonio Hungaro DuarteAbstract:Abstract Introduction The aim of this study was to evaluate the effects of large apical preparations in the Danger Zones of the mesial root canals of mandibular molars instrumented with the Mtwo and Reciproc systems (VDW, Munich, Germany) until reaching apical diameters of 0.25 and 0.40 mm. Methods Twelve mandibular molars, the mesial roots of which presented distinct foramens and similar anatomies, were selected using micro–computed tomographic scanning. Mtwo and Reciproc instruments were used to shape the mesiobuccal or mesiolingual canals. The mesial canals were scanned before and after the use of 0.25- and 0.40-mm Mtwo and Reciproc instruments. The analyzed parameters included the root canal volume and remaining dentin thickness at 5 different levels. The obtained data were subjected to paired analysis of variance and Tukey or Friedman and Dunn tests for intragroup analysis and the Mann-Whitney U test for comparison between the mesial and distal walls. Results There were no significant differences between the mesial and distal dentin thickness for the points analyzed with both instrumentation techniques (P > .05). The volumetric analysis revealed a significant difference (P Conclusions Both systems performed similarly for the preparation of curved root canals with separate apical foramens. The increase of the root canal preparation with the 0.40-mm instrument significantly increased the root canal volume at the apical third without significantly reducing the dentin thickness in the Danger Zone for both instrument systems.
Ta Chung Wang - One of the best experts on this subject based on the ideXlab platform.
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Obstacle detection and avoidance with noisy measurements using Danger Zone concepts
Journal of The Chinese Institute of Engineers, 2015Co-Authors: Ta Chung WangAbstract:Potential collision Danger increases if a vehicle gradually moves closer to other vehicles or obstacles. If the collision time can be predicted before the vehicle is Dangerously close to other vehicles or obstacles, the vehicle can devise an effective evasive maneuver or reroute its path, thus avoiding collision. This paper proposes an obstacle avoidance algorithm for unmanned vehicles in an unknown environment. The proposed avoidance algorithm uses the Danger Zone concept to determine whether the obstacle or surrounding vehicle will cause a possible collision. The Danger Zone is constructed around the vehicle by using semi-algebraic functions. The possible collision can be predicted by checking the sign of these semi-algebraic functions. The semi-algebraic functions for constructing the Danger Zone apply the relative velocities between the vehicle, and other vehicles or obstacles and can be used for both two- and three-dimensional cases. Several avoidance schemes are provided, with examples to demonstrat...
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unmanned vehicle obstacle detection and avoidance using Danger Zone approach
Transactions of The Canadian Society for Mechanical Engineering, 2013Co-Authors: Ta Chung Wang, Tz Jian LinAbstract:This paper proposes an obstacle avoidance algorithm for unmanned vehicles in unknown environment. The vehicle uses an ultrasonic sensor and a servo motor which rotates from 0 to 180 degrees to obta...
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Unmanned vehicle obstacle avoidance using single sensor scan method and Danger Zone estimation
Applied Mechanics and Materials, 2013Co-Authors: Tz Jian Lin, Ta Chung WangAbstract:This paper proposes an obstacle avoidance algorithm for unmanned vehicles in unknown environment by a single sensor. The scan system is composed of an ultrasonic sensor and a servo motor which rotates from 0 to 180 degrees to obtain the distance data, and the profile of the obstacle can be depicted by a histogram which we use to find out the boundary of the obstacle. In this avoidance algorithm we will use the Danger Zone concept to judge whether the obstacle will cause a possible collision. The Danger Zone concept surrounds the vehicle by a sphere and uses the relative velocity to calculate the area in which obstacles will collide with the vehicle within a pre-specified time period. Combining the profile of the boundary of the obstacle with the Danger Zone concept, we can determine the maneuvers to avoid collisions.
Felipe Goncalves Belladonna - One of the best experts on this subject based on the ideXlab platform.
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Root groove depth and inter-orifice canal distance as anatomical predictive factors for Danger Zone in the mesial root of mandibular first molars
Clinical Oral Investigations, 2020Co-Authors: Gustavo De-deus, Felipe Goncalves Belladonna, Evaldo Almeida Rodrigues, Jong-ki Lee, J. Kim, Emmanuel João Nogueira Leal Silva, Daniele Moreira Cavalcante, Marco Simões-carvalho, Diogo Da Silva Oliveira, Marco Aurelio VersianiAbstract:Objectives This study evaluated the Danger Zone (DZ) in mesial roots of mandibular molars and the correlation between anatomical references of the DZ and some anatomical landmarks including tooth/root length, depth of mesial and distal grooves, and inter-canal orifices distance. Material and methods Twenty-eight mesial roots of mandibular molars with 2 independent canals were scanned and divided into 2 groups according to root length. The anatomical landmarks were correlated (Pearson or Spearman coefficients) with root level, thickness, and position of the DZ and also compared (independent samples t or Mann-Whitney tests) between the 2 groups at α = 5%. Results No statistical difference was observed between groups regarding DZ parameters and depth of mesial and distal grooves ( P > 0.05). Orifice distance in group 2 (4.49 ± 0.75 mm) was significantly greater than group 1 (3.76 ± 0.89 mm) ( P < 0.05). Significant correlations ( P < 0.05) were found between (i) DZ level and root/tooth length ( r = 0.54 and 0.49, respectively), (ii) DZ thickness and distal groove depth ( r = − 0.45), and orifice distance ( r = 0.38), and (iii) DZ position and depth of mesial ( r = 0.39) and distal ( r = 0.40) grooves. Other variables such as root length and distal groove depth ( r = 0.28), and orifice distance and mesial groove depth ( r = 0.36) were also correlated ( P < 0.05). Conclusions The length of tooth/root, the distance of canal orifices, and the depth of mesial/distal grooves of mesial roots of mandibular molars might be predictive factors for the root level, position, and thickness of the DZ. Clinical relevance The length, distance of mesial canal orifices, and the depth of mesial and distal grooves of the mesial roots of mandibular molars might be moderate predictive factors for the root level, position, and thickness of the DZ.
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Root groove depth and inter-orifice canal distance as anatomical predictive factors for Danger Zone in the mesial root of mandibular first molars.
Clinical oral investigations, 2020Co-Authors: Gustavo De-deus, Evaldo Rodrigues, Felipe Goncalves Belladonna, D M Cavalcante, Diogo Da Silva Oliveira, M. Simões‐carvalho, Jong-ki Lee, Emmanuel João Nogueira Leal Silva, Jeong-il Kim, Marco Aurelio VersianiAbstract:This study evaluated the Danger Zone (DZ) in mesial roots of mandibular molars and the correlation between anatomical references of the DZ and some anatomical landmarks including tooth/root length, depth of mesial and distal grooves, and inter-canal orifices distance. Twenty-eight mesial roots of mandibular molars with 2 independent canals were scanned and divided into 2 groups according to root length. The anatomical landmarks were correlated (Pearson or Spearman coefficients) with root level, thickness, and position of the DZ and also compared (independent samples t or Mann-Whitney tests) between the 2 groups at α = 5%. No statistical difference was observed between groups regarding DZ parameters and depth of mesial and distal grooves (P > 0.05). Orifice distance in group 2 (4.49 ± 0.75 mm) was significantly greater than group 1 (3.76 ± 0.89 mm) (P < 0.05). Significant correlations (P < 0.05) were found between (i) DZ level and root/tooth length (r = 0.54 and 0.49, respectively), (ii) DZ thickness and distal groove depth (r = - 0.45), and orifice distance (r = 0.38), and (iii) DZ position and depth of mesial (r = 0.39) and distal (r = 0.40) grooves. Other variables such as root length and distal groove depth (r = 0.28), and orifice distance and mesial groove depth (r = 0.36) were also correlated (P < 0.05). The length of tooth/root, the distance of canal orifices, and the depth of mesial/distal grooves of mesial roots of mandibular molars might be predictive factors for the root level, position, and thickness of the DZ. The length, distance of mesial canal orifices, and the depth of mesial and distal grooves of the mesial roots of mandibular molars might be moderate predictive factors for the root level, position, and thickness of the DZ.
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anatomical Danger Zone reconsidered a micro ct study on dentine thickness in mandibular molars
International Endodontic Journal, 2019Co-Authors: Gustavo Dedeus, Marco Aurelio Versiani, Evaldo Rodrigues, Felipe Goncalves Belladonna, M Simoescarvalho, D M Cavalcante, Diogo Da Silva Oliveira, Erick Miranda Souza, K A Giorgi, R T LopesAbstract:Aim To investigate the smallest dentine thickness in mesial canals of mandibular molars along the cervical and middle thirds of the root by means of a micro-computed tomographic (micro-CT) technology and digital image analysis. Methodology Fifty mesial roots of mandibular molars having two independent canals (mesiobuccal and mesiolingual), in the coronal and middle levels, were selected and scanned in a micro-CT device. After reconstruction procedures, approximately 468 slices per root covering the 7 mm below the furcation area of the mesial root were analysed to measure the smallest dentine thickness (Danger Zone [DZ]) in each slice from both distal and mesial regions of the mesial canals by an automatic segmentation process. Results The DZ values in the mesiobuccal canals varied from 0.67 to 1.93 mm, with an average of 1.13 ± 0.21 mm. For the mesiolingual canals, the DZ varied from 0.77 to 1.89 mm with an average of 1.10 ± 0.21 mm. There was no correspondence in the DZ between the mesiobuccal and mesiolingual canals at the same cross-sectional level in 71% of the specimens. Moreover, the smallest dentine thickness was towards the mesial region of the roots in 22% and 18% of the mesiolingual and mesiobuccal canals, respectively. (Figs 1 and 2 CONCLUSIONS: The smallest dentine thickness was on the mesial plane of the roots in about 40% of the canals. The vertical location of the DZ in relation to the furcation area was in the middle third of the root.
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Anatomical Danger Zone reconsidered: a micro-CT study on dentine thickness in mandibular molars.
International endodontic journal, 2019Co-Authors: Gustavo De-deus, Marco Aurelio Versiani, Evaldo Rodrigues, Felipe Goncalves Belladonna, D M Cavalcante, Diogo Da Silva Oliveira, Erick Miranda Souza, K A Giorgi, M. Simões‐carvalho, R T LopesAbstract:To investigate the smallest dentine thickness in mesial canals of mandibular molars along the cervical and middle thirds of the root by means of a micro-computed tomographic (micro-CT) technology and digital image analysis. Fifty mesial roots of mandibular molars having two independent canals (mesiobuccal and mesiolingual), in the coronal and middle levels, were selected and scanned in a micro-CT device. After reconstruction procedures, approximately 468 slices per root covering the 7 mm below the furcation area of the mesial root were analysed to measure the smallest dentine thickness (Danger Zone [DZ]) in each slice from both distal and mesial regions of the mesial canals by an automatic segmentation process. The DZ values in the mesiobuccal canals varied from 0.67 to 1.93 mm, with an average of 1.13 ± 0.21 mm. For the mesiolingual canals, the DZ varied from 0.77 to 1.89 mm with an average of 1.10 ± 0.21 mm. There was no correspondence in the DZ between the mesiobuccal and mesiolingual canals at the same cross-sectional level in 71% of the specimens. Moreover, the smallest dentine thickness was towards the mesial region of the roots in 22% and 18% of the mesiolingual and mesiobuccal canals, respectively. (Figs 1 and 2 CONCLUSIONS: The smallest dentine thickness was on the mesial plane of the roots in about 40% of the canals. The vertical location of the DZ in relation to the furcation area was in the middle third of the root. © 2019 International Endodontic Journal. Published by John Wiley & Sons Ltd.
