ABSTRACT
Objective @#To investigate the current status of hearing loss in a fastener manufacturing enterprise, and to analyze its influencing factors, so as to provide insights into occupational disease prevention and control. @*Methods@#The occupational health examination data of noise exposed workers and the workplace occupational disease hazard factors detection data in a fastener manufacturing enterprise in Jiaxing City in 2022 were collected through the Occupational Disease and Occupational Health Hazard Factors Detection System of China Disease Prevention and Control Information System, and factors affecting the development of high-frequency noise-induced hearing loss (HFNIHL) and speech-frequency noise-induced hearing loss (SFNIHL) were analyzed. @*Results@#Totally 625 workers were investigated, with a median age of 44.00 (interquartile range, 13.00) years and a median length of service of 8.00 (interquartile range, 9.00) years, and including 519 men (83.04%) and 106 women (16.96%). There were 309 workers with single noise exposure (49.44%) and 316 workers with joint noise exposure (50.56%), and 518 workers exposed to noise with the normalized continuous A-weighted sound pressure level equivalent to a 40 h working week (LEX,40 h) that exceeded the national standard (82.88%). The detection rates of HFNIHL and SFNIHL were 49.12% and 35.04%, respectively. Multivariable logistic regression analysis indicated that males (OR=10.528, 95%CI: 5.271-21.025), length of service of 10 years and longer (OR=2.451, 95%CI: 1.599-3.759), LEX,40 h of >85 dB (A) (OR=2.227, 95%CI: 1.318-3.764) and joint noise exposure (OR=3.002, 95%CI: 2.080-4.334) were associated with an increased risk of HFNIHL, and male (OR=9.400, 95%CI: 4.211-20.985), LEX,40 h of >85 dB (A) (OR=2.305, 95%CI: 1.345-3.951), and joint noise exposure (OR=3.880, 95%CI: 2.677-5.623) were associated with an increased risk of SFNIHL.@*Conclusion@#Gender, length of service, noise intensity and exposure mode are factors affecting the risk of HFNIHL, while gender, noise intensity and exposure mode are factors affecting the risk of SFNIHL.
ABSTRACT
Objective@# To evaluate the spatiotemporal relationship between the root apex of mandibular molars and the inferior alveolar nerve canal (IANC) in adults. @*Methods@#Cone-beam computed tomography (CBCT) images were collected in 236 patients, and the distances from the root apexes of mandibular molars to the IANC were measured in NNT 4.6 software. The relationship between distance and gender was evaluated. @*Results@#In two-rooted mandibular first molars, the distances from the mesial root and distal root to the IANC were 7.34 ± 2.07 mm and 6.69 ± 2.08 mm, respectively, in males and 6.47 ± 2.22 mm and 5.94 ± 2.11 mm in females. In three-rooted mandibular first molars, the distances from the mesial root, distobuccal root, and distolingual to the IANC were 7.29 ± 1.30 mm, 7.40 ± 2.33 mm, and 9.97 ± 2.19 mm, respectively, in males and 6.08 ± 2.57 mm, 6.35 ± 2.40 mm, and 9.01 ± 2.90 mm, respectively, in females. In one-rooted mandibular second molars, the distance from the root to the IANC was 4.09 ± 1.64 mm in males and 3.89 ± 1.76 mm in females. In two-rooted mandibular second molars, the distances from the mesial root and distal root to the IANC were 5.14 ± 2.08 mm and 4.39 ± 1.85 mm, respectively, in males and 3.78 ± 1.69 mm and 3.24 ± 1.72 mm, respectively, in females. There were no significant with in-gender differences between the left and right side in the distances from the root apexes to the IANC (P>0.05). The distances from the mandibular first molar were greater in males than in females. The longest average distance was from the distolingual root apexes of three-rooted mandibular first molars to the IANC, and the distances were longer from the distobuccal root apexes of three-rooted mandibular first molars to the IANC than from the distal root apexes of two-rooted mandibular first molars to the IANC (P<0.05). There was no within-gender difference in the distances from the root apexes of single-rooted mandibular second molars to the IANC (P>0.05), but the distances in two-rooted mandibular second molars were larger in males than in females (P<0.05). The distances from the root apexes to the IANC were smaller in mandibular second molars than in mandibular first molars (P<0.05). @*Conclusion @#There are significant differences between adult males and females in the distance from the root apex to the IANC for mandibular first molars and two-rooted mandibular second molars. The distances from the root apexes to the IANC were smaller in mandibular second molars than in mandibular first molars.