scholarly journals Root dentine thickness of danger zone in mesial roots of mandibular first molars

2020 ◽  
Author(s):  
Guangchao Zhou ◽  
Diya Leng ◽  
Mingming Li ◽  
Yang Zhou ◽  
Cuifeng Zhang ◽  
...  

Abstract Background: Better understanding of the danger zone anatomy in mesial roots (MRs) of mandibular first molars (MFMs) may serve to decrease the risk of mishaps. This study aimed to measure the minimal distal dentine thicknesses of danger zone in MRs of MFMs in a native Chinese population using cone-beam computed tomography (CBCT). Methods: CBCT images of 1792 MFMs from 898 Chinese patients were analyzed. The minimal distal dentine thicknesses of the mesiobuccal (MB) and mesiolingual (ML) canals below the furcation 1, 2, 3, 4, 5 mm were measured. The association between the minimal distal dentine thicknesses and the root lengths, patient’s age and gender, side were assessed. Results: The minimal distal dentine thicknesses of MB and ML canals are located 3∼4 mm below the furcation for both men and women. There are no differences between MB and ML canals, while the minimal distal dentine thicknesses of MB and ML canals were higher in men than women ( P <0.05), except at 1 and 3 mm of ML canals ( P >0.05). The minimal distal dentine thicknesses of MB and ML canals increased with age in both men and women at each location ( P <0.05). The minimum distal dentine thickness at every location were significantly different between long teeth and short teeth both in men and women ( P < 0.05), with short teeth having the smallest mean values. There are no significant differences between two sides ( P >0.05). Conclusions: The minimal distal dentine thicknesses of MRs in MSMs have close correlation with root length, patient’s age and gender.

2019 ◽  
Author(s):  
Guangchao Zhou ◽  
Diya Leng ◽  
Mingming Li ◽  
Yang Zhou ◽  
Cuifeng Zhang ◽  
...  

Abstract Background Better understanding of the danger zone anatomy in mesial roots (MRs) of mandibular first molars (MFMs) may serve to decrease the risk of mishaps. This study aimed to measure the minimal distal dentine thicknesses of danger zone in MRs of MFMs in a native Chinese population using cone-beam computed tomography (CBCT). Methods CBCT images of 1792 MFMs from 898 Chinese patients were analyzed. The minimal distal dentine thicknesses of the mesiobuccal (MB) and mesiolingual (ML) canals below the furcation 1, 2, 3, 4, 5 mm were measured. The association between the minimal distal dentine thicknesses and the root lengths, patient’s age and gender, side were assessed. Results The minimal distal dentine thicknesses of MB and ML canals are located 3∼4 mm below the furcation for both men and women. There are no differences between MB and ML canals, while the minimal distal dentine thicknesses of MB and ML canals were higher in men than women (P<0.05), except at 1 and 3 mm of ML canals (P>0.05). The minimal distal dentine thicknesses of MB and ML canals increased with age in both men and women at each location (P<0.05). The minimum distal dentine thickness at every location were significantly different between long teeth and short teeth both in men and women (P < 0.05), with short teeth having the smallest mean values. There are no significant differences between two sides (P>0.05). Conclusions The minimal distal dentine thicknesses of MRs in MSMs have close correlation with root length, patient’s age and gender.


2020 ◽  
Author(s):  
Guangchao Zhou ◽  
Diya Leng ◽  
Mingming Li ◽  
Yang Zhou ◽  
Cuifeng Zhang ◽  
...  

Abstract Background: Better understanding of the danger zone anatomy in mesial roots (MRs) of mandibular first molars (MFMs) may serve to decrease the risk of mishaps. This study aimed to measure the minimal distal dentine thicknesses of danger zone in MRs of MFMs in a native Chinese population using cone-beam computed tomography (CBCT). Methods: CBCT images of 1792 MFMs from 898 Chinese patients were analyzed. The minimal distal dentine thicknesses of the mesiobuccal (MB) and mesiolingual (ML) canals below the furcation 1, 2, 3, 4, 5 mm were measured. The association between the minimal distal dentine thicknesses and the root lengths, patient’s age and gender, side were assessed. Results: The minimal distal dentine thicknesses of MB and ML canals are located 3∼4 mm below the furcation for both men and women. There are no differences between MB and ML canals, while the minimal distal dentine thicknesses of MB and ML canals were higher in men than women ( P <0.05), except at 1 and 3 mm of ML canals ( P >0.05). The minimal distal dentine thicknesses of MB and ML canals increased with age in both men and women at each location ( P <0.05). The minimum distal dentine thickness at every location were significantly different between long teeth and short teeth both in men and women ( P < 0.05), with short teeth having the smallest mean values. There are no significant differences between two sides ( P >0.05). Conclusions: The minimal distal dentine thicknesses of MRs in MSMs have close correlation with root length, patient’s age and gender.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Dilhan İlgüy ◽  
Mehmet İlgüy ◽  
Erdoğan Fişekçioğlu ◽  
Semanur Dölekoğlu ◽  
Nilüfer Ersan

Aim. The aim of the present study was to examine the relationship between articular eminence inclination, height, and thickness of the roof of the glenoid fossa (RGF) according to age and gender and to assess condyle morphology including incidental findings of osseous characteristics associated with osteoarthritis (OA) of the temporomandibular joint (TMJ) using cone beam computed tomography (CBCT).Materials and Methods. CBCT images of 105 patients were evaluated retrospectively. For articular eminence inclination and height, axial views on which the condylar processes were seen with their widest mediolateral extent being used as a reference view for secondary reconstruction. Condyle morphology was categorized both in the sagittal and coronal plane.Results. The mean values of eminence inclination and height of males were higher than those of females (P<0.05). There were significant differences in the RGF thickness in relation to sagittal condyle morphology. Among the group of OA, the mean value of the RGF thickness for “OA-osteophyte” group was the highest (1.59 mm), whereas the lowest RGF values were seen in the “OA-flattening.”Conclusion. The sagittal osteoarthritic changes may have an effect on RGF thickness by mechanical stimulation and changed stress distribution. Gender has a significant effect on eminence height (Eh) and inclination.


2020 ◽  
Vol 69 (1) ◽  
Author(s):  
Andrea Pilloni ◽  
Lorenza Montanaro ◽  
Fabiola Dell'olmo ◽  
Alberto Fonzar ◽  
Francesco Cairo ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Suju Wang ◽  
Wenyang Hao ◽  
Chunxiao Xu ◽  
Daofeng Ni ◽  
Zhiqiang Gao ◽  
...  

Objective(s). The purpose of this study was to explore the effectiveness of wideband acoustic immittance (WAI) in the diagnosis of otosclerosis by comparing the differences in the energy reflectance (ER) of WAI between patients with otosclerosis and age- and gender-matched normal hearing controls in the Chinese population. Methods. Twenty surgically confirmed otosclerotic ears were included in the otosclerotic group. The ER of WAI at ambient and peak pressures, resonance frequency, and 226-Hz tympanogram were collected prior to surgery using a Titan hearing test platform (Interacoustics A/S, Middelfart, Denmark). All diagnoses of otosclerosis in the tested ear were confirmed by surgery after the measurements. Thirteen normal adults (26 ears) who were age- and gender-matched with the otosclerotic patients were included as the control group. Results. At peak pressure, the ERs of otosclerotic patients were higher than those of the control group for frequencies less than 4,000Hz and were lower for frequencies greater than 4,000Hz. In addition, within the analyzed frequencies, the differences observed at 2,520Hz was statistically significant (p<0.05/16=0.003, Bonferroni corrected). At ambient pressure, the differences observed at 1,260 and 6,350Hz were statistically significant (p<0.05/16=0.003, Bonferroni corrected). Although the differences between the otosclerotic and control groups exhibited similar trends to those in studies implemented in Caucasian populations, the norms in the present study in the control group were different from those in the Caucasian populations, suggesting racial differences in WAI test results. Regarding the middle ear resonance frequency, no significant difference was observed between the two groups (P>0.05). Conclusion. WAI can provide valuable information for the diagnosis of otosclerosis in the Chinese population. Norms and diagnostic criteria corresponding to the patient’s racial group are necessary to improve the efficiency of WAI in the diagnosis of otosclerosis.


2008 ◽  
pp. 2284-2298
Author(s):  
M. B. Knight ◽  
J. M. Pearson

As the changing demographics of the workplace influence how organizations operate, the need to reexamine relationships between these demographic variables and their effect on the organization continues. This study provides an empirical examination of the effect of two demographic variables, age and gender, and any moderating impact anxiety, enjoyment, and/or peer pressure may have on computer usage. Based on our analysis of 292 knowledge workers, we identified no significant difference between men and women and/or young and old regarding their computer usage in the workplace. Therefore, the findings from this study do not seem to support earlier research regarding age and gender, which indicated that these variables did impact computer usage. However, the moderating construct (anxiety) did appear to be significant in the employees’ computer usage.


2011 ◽  
Vol 33 (4) ◽  
pp. 367-373 ◽  
Author(s):  
Cynthia C Wolle ◽  
Marcos Sanches ◽  
Monica L Zilberman ◽  
Raul Caetano ◽  
Marcos Zaleski ◽  
...  

OBJECTIVE: To examine sex differences in alcohol consumption according to age groups, and to assess gender and age effects on several aspects of alcohol consumption patterns. METHOD: Based on a Brazilian nationwide representative sample (n = 3,007), we analysed the differences in drinking patterns between genders. We also assessed the effects of gender, age, and gender by age interaction for alcohol consumption dimensions (frequent drinking, usual intake, binge drinking, and frequent binge drinking), using logistic and negative binomial regression models. RESULTS: Gender, age, and gender by age interaction had significant effects on the predictive models for all studied drinking patterns, except for the 'usual' dosage. The effect of gender on drinking patterns varies with age. While gender has a greater effect in older age groups, the difference between men and women decreased in the younger age groups. CONCLUSIONS: Gender convergence regarding alcohol use is a trend that might be influenced by environmental factors and should be addressed in prevention and treatment programs, as well as in public health policies.


1981 ◽  
Vol 13 (3) ◽  
pp. 183-193 ◽  
Author(s):  
Pamela E. Cooper ◽  
L. Eugene Thomas ◽  
Scott J. Stevens ◽  
David Suscovich

The roles chronological age and gender play in subjective time experience were explored in a sample of 294 adult men and women. Subjective time experience (STE: the difference between subjective age and chronological age) was found to vary widely among individuals, with some being “accurate” (SA = CA), and others either “retarded” (SA < CA) or “advanced” (SA > CA). Males were more retarded in STE than females at every point in the lifespan, and patterns of age differences in adulthood differed for the two sexes as well. The results suggest that chronological age may play a key role in transitions in STE, and that chronological age is more significant in the STE of women than in the STE of men.


2018 ◽  
Vol 23 (1) ◽  
Author(s):  
Fernanda Gomez Corrêa ◽  
Claudia Bohrer Flores ◽  
Flávia Kolling Marquezan ◽  
Gabriela Salatino Liedke ◽  
Gustavo Nogara Dotto ◽  
...  

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.


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