A retrospective study of factors contributing to anchorage loss in upper premolar extraction cases.

Background: Anchorage control is one of the components in the treatment of extraction cases. However, what determines more or less anchorage loss is still an unanswered question. Aim: The purpose of this study was to investigate the most important factors contributing to the anchorage loss of maxillary first molars in premolar extraction cases. Materials and Methods: The study included 726 upper premolar extraction cases, including 214 male patients and 512 female patients, and the mean age was 14.4 ± 4.5 years old (range: 9-45). Factors including physiological characteristics, treatment mechanics, and cephalometric variables were collected and their influences on the angulation changes of maxillary first molars were analyzed. Results: The mean angulation change of maxillary first molar after treatment was 2.81°(mesial tipping). The change of UM/PP showed a statistically significant difference in different sex (male 3.84° ± 5.26° vs female 2.38° ± 5.10°), age (adult -0.05° ± 4.73° vs teenager 3.46° ± 5.07°), and molar relationship (Class II 3.28° ± 5.15° vs Class I 2.36° ± 5.19°). There are six variables accounted in the regression analysis (R = 0.608, R2 = 37.0%). Among them, the pre-treatment molar tipping (Standardized Coefficients: -0.65) and the pre-treatment incisor/molar height ratio (Standardized Coefficients: -0.27) were the most important factors influencing anchorage loss during treatment. Conclusion: Compared with treatment-related factors, the patient's physiological characteristics play a more important role in anchorage loss. The pre-treatment angulation of the maxillary first molar is the most influential factor in changes to maxillary molar angulation, which are often predisposing anchorage loss.

Antifouling properties of amphiphilic poly(3-hydroxyalkanoate): an environmentally-friendly coating.

The development of biofouling is a major problem for marine industries. The conception of antifouling and fouling release coatings, with controlled physical-chemical properties is a promising strategy. Among them, amphiphilic systems, such as those composed of a hydrophobic polydimethylsiloxane matrix and a hydrophilic polyethyleneglycol additive are the most efficient and up to date. Despite their effectiveness, these systems are questioned due to the petrochemical origin of PDMS. The aim of this project was to substitute the PDMS matrix with a biopolymer, poly(3-hydroxybuyrate-co-3-hydroxyvalerate) and to improve its anti-adhesion properties through the elaboration of an amphiphilic system, via the addition of PEG or PHBHHx-b-PEG copolymer. The results, including the physico-chemical properties of PHBHV based coatings and static adhesion tests on a marine bacterium, Bacillus 4J6 and a diatom, Phaeodactylum tricornutum are compared with those of PDMS and PEG-modified PDMS coatings. Real antiadhesion activity was obtained for the PHBHV/PHBHHx-b-PEG system for a promising eco-friendly strategy.

Porous metal wedge augments to address glenoid retroversion in anatomic shoulder arthroplasty: midterm update.

BACKGROUND: Wedge-shaped porous metal augments were used to address bone deficiency in shoulder arthroplasty as part of a hybrid combination of high-density polyethylene, polymethyl methacrylate bone cement, and porous metal implant. This article presents an ongoing review of the use of the generically designed augments in the shoulder to address glenoid retroversion as part of anatomic total shoulder arthroplasty (aTSA). MATERIALS: Seventy-five shoulders in 66 patients (23 women and 43 men, aged 42-85 years) with Walch grade B2 or C glenoids underwent porous metal glenoid augment (PMGA) insertion as part of aTSA. Patients underwent preoperative 3-dimensional (3D) templating; based on that planning, patients received either a 15° or 30° PMGA wedge (secured by screws to the native glenoid) to correct excessive glenoid retroversion before a standard glenoid component was implanted using bone cement. Neither patient-specific guides nor navigation were used. Intraoperative glenoid alignment was assessed using a reusable guide that referenced the anterior scapular neck. Patients were prospectively assessed using shoulder functional assessments (Oxford Shoulder Score [OSS], American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], visual analog scale [VAS] pain scores, and forward elevation [FE]) preoperatively; at 3, 6, and 12 months postoperation; and yearly thereafter, with similar radiologic surveillance. RESULTS: Of the total consecutive series, 49 shoulders had a follow-up of greater than 24 months, with a median follow-up of 48 months (range: 24-87 months). For this cohort, median outcome scores improved for OSS (21 to 44), ASES (24 to 92), VAS (7 to 0), and FE (90° to 140°) from preoperative outcomes to the most recent review, respectively. Four patients died, but no others were lost to follow-up. Apart from 1 infection at 18 months postoperatively and 1 minor peg perforation, there were no complications, hardware failures, implant displacements, significant lucency, or posterior resubluxations. Radiographs showed good incorporation of the wedge augment, with correction of glenoid retroversion from median 22° (13° to 46°) to 4° (17° to anteversion 16°). All but 4 glenoids were corrected to within the target range (less than 10° retroversion), and only 2 glenoid components were implanted outside 15° of neutral glenoid version. CONCLUSIONS: The porous metal wedge-shaped augments effectively addressed posterior glenoid deficiency as part of aTSA for rotator cuff intact osteoarthritis, producing satisfactory clinical outcomes with no signs of impending future failure.

[Retrospective investigation on explosive hearing loss of injured persons in explosion accidents involving a steel enterprise].

Objective: Through the investigation of the injured persons in explosion accidents, the impact of wearing the ear protectors device (anti-noise earplugs) on the auditory organs and hearing loss of the injured person was understood, which could provide reference for the clinical diagnosis, treatment and prevention of the explosive hearing impairment. Methods: A retrospective survey was conducted on 39 directly injured persons who were injured in 23 explosion accidents involving a steel plant from 1990 to 2016 as the explosive hearing loss, taking the time of the patient＇s injury and 3-6 months after the injury as the time of investigation and evidence collection, and according to whether to wear the ear protectors device for group comparison and statistical analysis. Results: There was no significant difference between the two groups in hearing loss, tinnitus, earache, headache, some patients with dizziness and craniocerebral injury, regardless of whether the injured person wore anti-noise earplugs or not (P=0.444-1) , the shock (coma) patients in the non-protected group were more common (34.8%, 8/23) , and the difference was statistically significant (P=0.012) ; Although auricle injury was detected in both groups and there was no significant difference between the two groups (P=1) , but the external ear canal injury, tympanic membrane perforation were more common in the non-protected group, and there was no external ear canal and tympanic membrane perforation in the wearing earplug group, and the difference between the two groups was significant (P=0.000) . After 3-6 months, the rehabilitation of auditory system and other symptoms in patients showed that the hearing loss, tinnitus, earache, headache, dizziness and other symptoms all disappeared in patients wearing earplugs, while the above symptoms in the non-protected group were improved but more persisted, and the difference between the two groups was statistically significant (P=0.000-0.012) , and there was no significant difference in rehabilitation conditions such as craniocerebral injury between the two groups (P=1) ; There were patients with unhealed auricle injury in both groups in 3-6 months after the injury, and there was no significant difference between the two groups (P=1) , however, in the non-protected group, 69.57% (16/23) of the patients with external auditory canal injury were still unhealed and none of the patients with tympanic membrane perforation recovered, and the difference between the two groups was obvious (P=0.000~0.001) ; Pure tone air conduction examination showed that the hearing of the earplugs wearers was well recovered at the time of the explosion, while irreversible hearing impairment was common in the non-protective group, the difference was statistically significant (P=0.000) . Conclusion: Ear protector plays an important role in protecting the auditory organs and hearing of workers in explosion accident, and it is an effective protective measure to prevent and reduce the damage of external ear canal, perforation of tympanic membrane and explosive hearing loss caused by explosion accidents.

[Analysis on the effect of sound insulation reconstruction in operation room of steel rolling production line in a steel plant].

Objective: To investigate the effect of sound insulation improvement on the noise exposure of workers in the operation room of hot rolling line for wide and heavy plate. Methods: From September 2019 to September 2017, based on the occupational health Survey, the data of 25 fixed operation rooms and workers in operation rooms of a steel rolling production line were collected retrospectively, the noise exposure levels before and after the improvement of sound insulation were statistically analyzed. Results: The noise exposure value of the workers, the qualified rate of 0 Grade 8 hours equivalent noise (L(EX, 8 h)) ≤85 dB (A) and the qualified rate of the design limit value of the operation room were all higher than those before the modification, the difference was statistically significant (P<0.01) , after the renovation, the Class II and above noise hazards were eliminated, the equivalent continuous a sound level (L(Aeq, 8 h)) >75 dB (A) of the workers in the operation room was 8h, and the noise level in the operation room still did not meet the Ergonomics limit standard. Conclusion: The improvement of sound insulation can effectively improve the working environment of noise workplace operating room and reduce the workers'noise exposure level.

[Exploring a new method for superimposition of pre-treatment and post-treatment mandibular digital dental casts in adults].

OBJECTIVE: To explore a cone beam computed tomography (CBCT)-independent method for mandibular digital dental cast superimposition to evaluate three-dimensional (3D) mandibular tooth movement after orthodontic treatment in adults, and to evaluate the accuracy of this method. METHODS: Fifteen post-extraction orthodontic treatment adults from the Department of Orthodontics, Peking University School and Hospital of Stomatology were included. All the patients had four first premolars extracted, and were treated with straight wire appliance. The pre- and post-treatment plaster dental casts and craniofacial CBCT scans were obtained. The plaster dental casts were transferred to digital dental casts by 3D laser scanning, and lateral cephalograms were created from the craniofacial CBCT scans by orthogonal projection. The lateral cephalogram-based mandibular digital dental cast superimposition was achieved by sequential maxillary dental cast superimposition registered on the palatal stable region, occlusal transfer, and adjustment of mandibular rotation and translation obtained from lateral cephalogram superimposition. The accuracy of the lateral cephalogram-based mandibular digital dental cast superimposition method was evaluated with the CBCT-based mandibular digital dental cast superimposition method as the standard reference. After mandibular digital dental cast superimposition using both methods, 3D coordinate system was established, and 3D displacements of the lower bilateral first molars, canines and central incisors were measured. Differences between the two superimposition methods in tooth displacement measurements were assessed using the paired t-test with the level of statistical significance set at P<0.05. RESULTS: No significant differences were found between the lateral cephalogram-based and CBCT-based mandibular digital dental cast superimposition methods in 3D displacements of the lower first molars, and sagittal and vertical displacements of the canines and central incisors; transverse displacements of the canines and central incisors differed by (0.3±0.5) mm with statistical significance. CONCLUSION: The lateral cephalogram-based mandibular digital dental cast superimposition method has the similar accuracy as the CBCT-based mandibular digital dental cast superimposition method in 3D evaluation of mandibular orthodontic tooth displacement, except for minor differences for the transverse displacements of anterior teeth. This method is applicable to adult patients with conventional orthodontic treatment records, especially the previous precious orthodontic data in the absence of CBCT scans.

[A cohort study on occupational noise induced hearing loss in workers at an iron and steel plant].

Objective: To analyze the incidence rate of occupational noise-induced hearing loss in noise-exposed workers in an iron and steel plant from 2006 to 2015. Methods: Using a cohort study method, workers exposed to occupational noise from Jan 1, 2006 to Dec 12, 2015 were followed up and the pure tone hearing test was conducted. In total, 6 297 subjects completed two or more physical checks and the pure tone hearing test and were included in the analysis. The noise exposure level at the workplace and the equivalent continuous A-weighted sound pressure level for workers was monitored and the cumulative noise exposure dose was evaluated. The subjects were divided into low, middle and high exposure groups according to the noise exposure level, and the equivalent continuous A-weighted sound pressure level for 8 hours for each group was 80.6-85.0, 85.1-90.0 and 90.1-103.4 dB (A), respectively. While the RR and 95% CI were derived from unconditional logistic regression models. In logistic regression analysis, confounding factors such as age, gender, smoking habit, drinking habit, high temperature exposure and chemical hazards exposure level were controlled. Results: During the follow-up period, 392 cases of occupational noise-induced hearing loss were diagnosed among the 6 297 subjects, with an incidence rate of 6.23%; 318 cases of high-frequency hearing loss were diagnosed, with an incidence rate of 5.05%; and 74 cases of occupational noise-induced deafness were diagnosed, with an incidence rate of 1.18% . The incidence rates of hearing loss among the high, medium and low exposure groups were 9.22% (158/1 737), 6.49% (204/3 142) and 2.08% (30/1 442), respectively; the rates of high-frequency hearing loss were 7.41% (127/1 737), 5.25% (165/3 142) and 1.80% (26/1 442), respectively; and the rates of occupational noise-induced deafness were 1.81% (31/1 737), 1.24% (39/3 142) and 0.28% (4/1 442), respectively. For the groups corresponding to cumulative noise exposure doses of ≤84.99, 85.00- 87.99, 88.00- 90.99, 91.00- 93.99, 94.00- 96.99, 97.00- 100.99, 101.00- 102.99 and ≥103.00 dB (A) · year, the incidence rates of hearing loss were 0 (0/185), 1.22% (2/164), 2.52% (17/674), 3.83% (35/913), 5.80% (106/1 827), 6.02% (67/1 113), 9.20% (95/1 003) and 18.04% (70/388), respectively. Compared with the low exposure group, the RR of hearing loss, high-frequency hearing loss and occupational noise-induced deafness for the high exposure group were 4.78 (95% CI: 3.22- 7.11), 4.36 (95% CI: 2.84- 6.69) and 6.63 (95% CI: 2.33- 18.82), respectively; and for the medium exposure group were 3.27 (95% CI: 2.22-4.82), 3.02 (95% CI: 1.99-4.59) and 4.52 (95% CI: 1.61-12.67), respectively. Conclusion: The incidence rate of hearing loss for workers exposed to noise in an iron and steel plant was related to the cumulative noise exposure dose, gender, age, educational level, smoking habits, drinking habits and exposure to high temperature.

[Association between eye absent homolog 4 gene polymorphisms and occupational noise-induced hearing loss].

Objective: To identify the association between genetic polymorphisms in the eye absent homolog 4 (EYA4) gene and noise-induced hearing loss (NIHL). Method: A nested case control study was conducted based on a cohort of noise-exposed subjects. In total, 292 cases were selected from a steel factory from 6 297 subjects during Jan 1, 2006 to Dec 12, 2015,who had an average hearing threshold of more than 40 dB(A); 584 matched control subjects for each case were designated on the basis of matched criteria including same gender, age (±5 years) and duration of exposure to noise (±2 years). What's more, the control group had an average hearing threshold of less than 35 dB(A) in high frequency and less than 25 dB(A) in speech frequency. Four single nucleotide polymorphisms (SNPs) of the EYA4 gene were genotyped using a SNPscanTM multiplex SNP genotyping kit. Hardy-Weinberg equilibrium tests were performed using a χ2 test for goodness-of-fit for each SNP among the control group, and the effects of genotypes of the EYA4 gene on NIHL were analyzed by logistic regression. The haplotypes were established and their frequencies in the two groups were assessed using Haploview 4.2 and Phase 2.1 software, and interactive effects between haplotypes and cumulative noise exposure were analyzed. Results: The average age of the subjects was (40.1±8.4) years and the average number of noise-exposed working years was 20.3 (8.4, 27.3) years. The range of noise exposure levels and the cumulative noise exposure were 80.2- 98.8 dB (A) and 86.6- 111.2 dB(A) · year, respectively. After adjustment for covariates including height, blood pressure, drinking status and smoking status, in the noise intensity>85 dB (A) group, subjects carrying the rs3813346 TT genotype had a higher NIHL risk than those carrying the GG genotype, and the adjusted OR (95% CI) value was 2.12 (1.21- 3.69). In the cumulative noise exposure>98 dB (A) · year group, compared with haplotype TGC, haplotype CGT showed a protective effect in the development of NIHL, with an adjusted OR (95% CI) value of 0.60 (0.37-0.97), however, the significance of intercation between EY4 gene of noise was lost after Bonferroni correction. Conclusion: Genetic polymorphism in the EYA4 gene may be a genetic susceptibility factor for NIHL.

Epidemiological characteristics and influential factors of hand, foot and mouth disease (HFMD) reinfection in children in Anhui province.

Hand, foot and mouth disease (HFMD) is an acute contagious condition caused by a spectrum of human enteroviruses. HFMD reinfection is common in the absence of cross-protection from other virus subtypes. This study focused on reinfection in children in Anhui province, China between 2008 and 2013 using surveillance system data. We classified 8960 cases as reinfected, corresponding to a rate of 2·02%. The reinfection rate was higher in boys than in girls [odds ratio (OR) 1·27, 95% confidence interval (CI) 1·21-1·32, P < 0·001], children aged < 3 years (OR 3·82, 95% CI 3·58-4·07, P < 0·001), and children living in rural areas (OR 1·09, 95% CI 1·04-1·14, P = 0·001). The reinfection rate in children who were originally infected with non-enterovirus A71 (non-EVA71) enteroviruses was higher than those infected with EVA71 (OR 1·36, 95% CI 1·02-1·80, P = 0·034). Influential factors of reinfection rate included annual incidence (ß coefficient = 0·715, P = 0·002) and the proportion of EVA71 in patients with mild HFMD (ß coefficient = -0·509, P = 0·018). These results demonstrate that boys aged <3 years, especially those in rural areas or regions with a lower EVA71 proportion are more prone to reinfection, and specific health education programmes should be developed to protect these susceptible populations.

[Morphological analysis of roots and alveolar bone changes after upper anterior retraction with maximum anchorage based on cone-beam computed tomography].

OBJECTIVE: To investigate the remodeling of alveolar bone and the changes of roots after anterior retraction with maximum anchorage by analyzing CBCT data from adult cases. METHODS: The sample comprised 48 incisors and 24 canines from 12 patients (18 to 40 years of age) with problems of maxillary protrusion or upper arch protrusion. CBCT scans were exposed before and after treatment, and lateral cephalometric images as well as multiple planar reconstruction images were reconstructed. Tracing superimpositions of sagittal sections and three-dimensional reconstructions were done for qualitative analysis. For all maxillary anterior teeth, changes of root length, alveolar bone height and labial-palatal thicknesses at different levels were evaluated. The average of measurements taken by the same tester in three times was processed by SPSS 17.0 statistical package. RESULTS: In 6 of the 12 cases, alveolar thickness became thinner on labial side [apical area: (-0.64±1.18) mm] while thicker on palatal side [apical area: (0.93±2.0) mm] and the root length decreased[(-0.95±0.79) mm]. In the other 6 cases, the incisors' alveolar bone became thicker on labial side [apical area: (2.12±1.46) mm] while thinner on palatal side [apical area: (-2.88±0.58) mm]and the loss of root length was obvious[(-2.12±1.43) mm]. In all the 12 cases, the canines' alveolar bone became thinner on labial side especially on the apical level[(-0.27±1.86) mm] while greatly thicker on palatal side [apical area: (6.40±6.00) mm]and the root resorption was slight [(-1.12±1.19) mm]. For all the anterior teeth, the height of alveolar bone reduced around them after retraction. CONCLUSION: When the root apical moved more palatally, more root resorption would occur and the alveolar bone would get thicker on labial side but thinner on palatal side and thinner as a whole after anterior retraction with maximum anchorage.In the vertical direction, the height of the alveolar bone generally decreased on all sides and decreased the most on the palatal side.

[Morphological analysis of roots and alveolar bone changes after upper anterior retraction with maximum anchorage based on cone-beam computed tomography].

OBJECTIVE: To investigate the remodeling of alveolar bone and the changes of roots after anterior retraction with maximum anchorage by analyzing CBCT data from adult cases. METHODS: The sample comprised 48 incisors and 24 canines from 12 patients (18 to 40 years of age) with problems of maxillary protrusion or upper arch protrusion. CBCT scans were exposed before and after treatment, and lateral cephalometric images as well as multiple planar reconstruction images were reconstructed. Tracing superimpositions of sagittal sections and three-dimensional reconstructions were done for qualitative analysis. For all maxillary anterior teeth, changes of root length, alveolar bone height and labial-palatal thicknesses at different levels were evaluated. The average of measurements taken by the same tester in three times was processed by SPSS 17.0 statistical package. RESULTS: In 6 of the 12 cases, alveolar thickness became thinner on labial side [apical area: (-0.64±1.18) mm] while thicker on palatal side [apical area: (0.93±2.0) mm] and the root length decreased[(-0.95±0.79) mm]. In the other 6 cases, the incisors' alveolar bone became thicker on labial side [apical area: (2.12±1.46) mm] while thinner on palatal side [apical area: (-2.88±0.58) mm]and the loss of root length was obvious[(-2.12±1.43) mm]. In all the 12 cases, the canines' alveolar bone became thinner on labial side especially on the apical level[(-0.27±1.86) mm] while greatly thicker on palatal side [apical area: (6.40±6.00) mm]and the root resorption was slight [(-1.12±1.19) mm]. For all the anterior teeth, the height of alveolar bone reduced around them after retraction. CONCLUSION: When the root apical moved more palatally, more root resorption would occur and the alveolar bone would get thicker on labial side but thinner on palatal side and thinner as a whole after anterior retraction with maximum anchorage.In the vertical direction, the height of the alveolar bone generally decreased on all sides and decreased the most on the palatal side.

[Factors influencing electrocardiogram results in workers exposed to noise in steel-making and steel-rolling workshops of an iron and steel plant].

OBJECTIVE: To investigate the factors influencing the electrocardiogram results in the workers exposed to noise in steel-making and steel rolling workshops of an iron and steel plant. METHODS: From September to December, 2013, cluster sampling was used to select 3 150 workers exposed to noise in the steel-making and steel-rolling workshops of an iron and steel plant, and a questionnaire survey and physical examinations were performed. The number of valid workers was 2 915, consisting of 1 606 workers in the steel-rolling workshop and 1 309 in the steel-making workshop. The electrocardiogram results of the workers in steel-making and steel-rolling workshops were analyzed. RESULTS: The overall abnormal rate of electrocardiogram was 26.35%, and the workers in the steel-making workshop had a significantly higher abnormal rate of electrocardiogram than those in the steel-rolling workshop(32.24% vs 21.54%, P<0.05). Male workers had a significantly higher abnormal rate of electrocardiogram than female workers(27.59% vs 18.61%, P<0.05). The workers with a drinking habit had a significantly higher abnormal rate of electrocardiogram than those who did not drink(28.17% vs 23.75%, P<0.05). The workers exposed to high temperature had a significantly higher abnormal rate of electrocardiogram than those who were not exposed to high temperature(29.43% vs 20.14%, P<0.05). The abnormal rates of electrocardiogram in the workers with cumulative noise exposure levels of <90, 90~94, 95~99, 100~104, and 105~113 dB(A)·year were 21.21%, 21.76%, 26.50%, 27.27%, and 32.16%, respectively, with significant differences between any two groups(P<0.05). The multivariate logistic regression analysis showed that a cumulative noise exposure of 105-113 dB(A)·year(OR=1.36, 95% CI: 1.03~1.80), a drinking habit(OR=1.20, 95% CI: 1.01~1.43), and high temperature(OR=1.60, 95% CI: 1.32~1.92) were the risk factors for abnormal electrocardiogram results. CONCLUSION: High cumulative noise exposure, alcohol consumption, and high temperature may affect the abnormal rate of electrocardiogram in the workers exposed to noise in steel-making and steel-rolling workshops.

[Association between serum magnesium ion level and risk of noise-induced hearing loss].

Objective: To investigate the association between serum magnesium ion level and risk of noise-induced hearing loss (NIHL) . Methods: Acohort study was performed for 7 445 workers exposed to noise in the steelmaking and steel rolling workshops of an iron and steel enterprise in Henan Province, China. The follow-up time was from January 1, 2006 to December 31, 2015. The workers with a binaural average high-frequency hearing threshold of ≥40 dB (HL) were enrolled as case group, and those with a binaural average high-frequency hearing threshold of <35 dB (HL) and a binaural average speech frequency of ≤25 dB (HL) were enrolled as control group. After being matched for age, working years of noise exposure, sex, and type of work at a ratio of 1∶1, 187 workers each were enrolled in the case group and the control group. Flame atomic absorption spectrometry was used to measure the serum magnesium ionlevel. Aconditional logistic regression analysis was performed to investigate the association of serum magnesium ion level, body mass index, cumulative noise exposure (CNE) , smoking, drinking, hypertension, and physical exercise with NIHL, as well as the association between serum magnesium ion level and risk of NIHL after the adjustment for covariants. Results: There was no significant difference in the serum magnesium ion level between the case group and the control group (24.63±7.92 mg/m(3) vs 24.91±7.33 mg/m(3), P>0.05) . Smoking (OR=1.687, 95%CI 1.090-2.613) was a risk factor for NIHL, and physical exercise (OR=0.509, 95%CI 0.325-0.796) reduced the risk of NIHL. In the workers with CNE>98 dB (A) ·year, the risk of NIHL in the workers with higher CNE was 1.305 times (95%CI 1.051-1.620) that in those with lower CNE. After the adjustment for CNE, smoking, and physical exercise, there was no significant difference in the influence of serum magnesium ion level on the risk of NIHL between the two groups (P>0.05) . Conclusion: Serum magnesium ion level may not be associated with NIHL. Increased CNE and smoking may increase the risk of NIHL and physical exercise may reduce the risk of NIHL.

A new method to evaluate the positional stability of a self-drilling miniscrew.

OBJECTIVES: To evaluate the positional stability of miniscrews during orthodontic treatment change in cone-beam computed tomography (CBCT). SETTING AND SAMPLE POPULATION: Twenty adult volunteers were enrolled. METHODS: In all participants, at least two maxillary first premolars were extracted because of protrusion. Each volunteer received six miniscrews in the maxilla, including two loaded miniscrews to retract anterior teeth and four unloaded miniscrews. CBCT scans were obtained at the beginning of space closure (T1) and approximately 11.8 months later (T2). Three-dimensional miniscrew models were constructed at T1 and T2, and the central axes were calculated using a principal component analysis (PCA) technique. Finally, we measured and compared the angle change of all the miniscrews from T1 to T2. RESULTS: The angle change values of the unloaded and loaded miniscrews were 1.64 ± 1.25° and 1.67 ± 1.15°, respectively. No significant differences in the angle change were observed. CONCLUSION: Cone-beam computed tomography images revealed both the unloaded and loaded miniscrews to be positionally stable during en-masse retraction in this study.

Subchondral chitosan/blood implant-guided bone plate resorption and woven bone repair is coupled to hyaline cartilage regeneration from microdrill holes in aged rabbit knees.

OBJECTIVE: Little is known of how to routinely elicit hyaline cartilage repair tissue in middle-aged patients. We tested the hypothesis that in skeletally aged rabbit knees, microdrill holes can be stimulated to remodel the bone plate and induce a more integrated, voluminous and hyaline cartilage repair tissue when treated by subchondral chitosan/blood implants. DESIGN: New Zealand White rabbits (13 or 32 months old, N = 7) received two 1.5 mm diameter, 2 mm depth drill holes in each knee, either left to bleed as surgical controls or press-fit with a 10 kDa (distal hole: 10K) or 40 kDa (proximal hole: 40K) chitosan/blood implant with fluorescent chitosan tracer. Post-operative knee effusion was documented. Repair tissues at day 0 (N = 1) and day 70 post-surgery (N = 6) were analyzed by micro-computed tomography, and by histological scoring and histomorphometry (SafO, Col-2, and Col-1) at day 70. RESULTS: All chitosan implants were completely cleared after 70 days, without increasing transient post-operative knee effusion compared to controls. Proximal control holes had worse osteochondral repair than distal holes. Both implant formulations induced bone remodeling and improved lateral integration of the bone plate at the hole edge. The 40K implant inhibited further bone repair inside 50% of the proximal holes, while the 10K implant specifically induced a "wound bloom" reaction, characterized by decreased bone plate density in a limited zone beyond the initial hole edge, and increased woven bone (WB) plate repair inside the initial hole (P = 0.016), which was accompanied by a more voluminous and hyaline cartilage repair (P < 0.05 vs control defects). CONCLUSION: In a challenging aged rabbit model, bone marrow-derived hyaline cartilage repair can be promoted by treating acute drill holes with a biodegradable subchondral implant that elicits bone plate resorption followed by anabolic WB repair within a 70-day repair period.

Pilot trial study of a compact macro-filtration membrane bioreactor process for saline wastewater treatment.

Conventional membrane bioreactor (MBR) systems have increasingly been studied in recent decades. However, their applications have been limited due to their drawbacks such as low flux, membrane fouling, and high operating cost. In this study, a compact macro-filtration MBR (MfMBR) process was developed by using a large pore size membrane to mitigate the membrane fouling problem. A pilot trial of MfMBR process was set up and operated to treat 10 m(3)/day of saline wastewater within 4 h. The system was operated under an average permeate flux of 13.1 m(3)/(m(2)·day) for 74 days. The average total suspended solids, total chemical oxygen demand, biological oxygen demand, total Kjeldahl nitrogen, and total nitrogen removal efficiencies achieved were 94.3, 83.1, 98.0, 93.1, and 63.3%, respectively, during steady-state operation. The confocal laser scanning microscopy image indicated that the backwash could effectively remove the bio-cake and dead bacteria. Thus, the results showed that the MfMBR process, which is essentially a primary wastewater treatment process, had the potential to yield the same high quality effluent standards as the secondary treatment process; thereby suggesting that it could be used as an option when the economic budget and/or land space is limited.

Factors affecting cement leakage in percutaneous vertebroplasty: a retrospective cohort study of 309 patients.

OBJECTIVE: Percutaneous vertebroplasty has been widely applied as a treatment for osteoporotic vertebral compression fracture. However, the incidence of cement leakage is high. The purpose of study is to identify the independent risk factors for cement leakage. PATIENTS AND METHODS: A total of 309 patients who suffered from osteoporotic vertebral compression fracture (OVCF) and underwent percutaneous vertebroplasty (PVP) were enrolled in this respective cohort study from January 2014 to January 2020. Clinical and radiological characteristics were assessed to identify independent predictors for each type of cement leakage, including age, gender, course of disease, fracture level, morphology of vertebral fracture, fracture severity, cortical disruption in vertebral wall or endplate, fracture line connected with basivertebral foramen, type of cement dispersion, and intravertebral cement volume. RESULTS: In leakage of B-type, fracture line connected with basivertebral foramen was identified as an independent risk factor [Adjusted OR: 2.837, 95% CI: (1.295, 6.211), p = 0.009]. For leakage of C-type, acute course of the disease, more severity of the fractured body, wall disruption and intravertebral cement volume (IVCV) were identified as independent risk factors [Adjusted OR: 0.409, 95% CI: (0.257, 0.650), p = 0.000]; [Adjusted OR: 3.128, 95% CI: (2.202, 4.442), p = 0.000]; [Adjusted OR: 6.387, 95% CI: (3.077, 13.258), p = 0.000]; [Adjusted OR: 1.619, 95% CI: (1.308, 2.005), p = 0.000]. Regarding leakage of D-type, biconcave fracture and endplate disruption were identified as independent risk factors [Adjusted OR: 6.499, 95% CI: (2.752, 15.348), p = 0.000]; [Adjusted OR: 3.037, 95% CI: (1.421, 6.492), p = 0.004]. For S-type, fracture in thoracic level and less severity of the fractured body were identified as independent risk factors [Adjusted OR: 0.105, 95% CI: (0.059, 0.188), p = 0.000]; [Adjusted OR: 0.580, 95% CI: (0.436, 0.773), p = 0.000]. CONCLUSIONS: Cement leakage was very common with PVP. Each cement leakage had its own influence factors. Preoperative identification of above influence factors for cement leakage could avoid the occurrence of severe sequelae.

Genetic variants in IFIH1 play opposite roles in the pathogenesis of psoriasis and chronic periodontitis.

The IFIH1 gene is a key factor connecting environmental and genetic factors in the pathogenesis of immune-related diseases. We aimed to investigate whether it has effects on psoriasis, chronic periodontitis and skin test-positive penicillin allergy and to confirm whether these diseases have shared molecular mechanisms originating from shared genetics. Two common variants in IFIH1 were genotyped in 561 patients with psoriasis, 421 patients with chronic periodontitis, 175 patients with skin test-positive penicillin allergy and 1100 shared controls. Then, case-control study was used to analyse the association between IFIH1 and the three diseases. The allele distributions of rs1990760 and rs3747517 in the Chinese population are much different from the European population. The A allele of rs1990760 (OR = 1.30, P = 5.4 × 10(-3)) and A-G (rs1990760/rs3747517) haplotype (OR = 1.31, P = 3.8 × 10(-3)) were highly associated with the risk of psoriasis. However, the A allele of rs1990760 (OR = 0.73, P = 7.8 × 10(-3)) and A-G haplotype (OR = 0.71, P = 4.5 × 10(-3)) were identified as protective factors for chronic periodontitis. IFIH1 affects several immune-related diseases, including psoriasis and chronic periodontitis, and provides a molecular link between genetic susceptibility, viral infections and immune-related diseases. Moreover, we also confirm the hypothesis that shared molecular mechanisms from common genetic variants contribute to a spectrum of immune-related diseases.

The benefits and risks of stem cell technology.

The potential impact of stem cell technology on medical and dental practice is vast. Stem cell research will not only provide the foundation for future therapies, but also reveal unique insights into basic disease mechanisms. Therefore, an understanding of stem cell technology will be necessary for clinicians in the future. Herein, we give a basic overview of stem cell biology and therapeutics for the practicing clinician.

Orthodontic Force-Induced BMAL1 in PDLCs Is a Vital Osteoclastic Activator.

Orthodontic tooth movement (OTM) depends on periodontal ligament cells (PDLCs) sensing biomechanical stimuli and subsequently releasing signals to initiate alveolar bone remodeling. However, the mechanisms by which PDLCs sense biomechanical stimuli and affect osteoclastic activities are still unclear. This study demonstrates that the core circadian protein aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) in PDLCs is highly involved in sensing and delivering biomechanical signals. Orthodontic force upregulates BMAL1 expression in periodontal tissues and cultured PDLCs in manners dependent on ERK (extracellular signal-regulated kinase) and AP1 (activator protein 1). Increased BMAL1 expression can enhance secretion of CCL2 (C-C motif chemokine 2) and RANKL (receptor activator of nuclear factor-κB ligand) in PDLCs, which subsequently promotes the recruitment of monocytes that differentiate into osteoclasts. The mechanistic delineation clarifies that AP1 induced by orthodontic force can directly interact with the BMAL1 promoter and activate gene transcription in PDLCs. Localized administration of the ERK phosphorylation inhibitor U0126 or the BMAL1 inhibitor GSK4112 suppressed ERK/AP1/BMAL1 signaling. These treatments dramatically reduced osteoclastic activity in the compression side of a rat orthodontic model, and the OTM rate was almost nonexistent. In summary, our results suggest that force-induced expression of BMAL1 in PDLCs is closely involved in controlling osteoclastic activities during OTM and plays a vital role in alveolar bone remodeling. It could be a useful therapeutic target for accelerating the OTM rate and controlling pathologic bone-remodeling activities.