Overbite depth indicator and anteroposterior dysplasia indicator cephalometric norms for African Americans

Objectives:To examine normal Overbite Depth Indicator (ODI) and Anteroposterior Dysplasia Indicator (APDI) values in African Americans and to compare them with mean values from white patients. Secondary aims were to compare mean ODI and APDI values among different age, gender, and combined age-gender groups in African American patients.Materials and Methods:Lateral cephalometric radiographs of 160 African American patients (97 boys and 63 girls; age, 7 to 14 years) with normal occlusion and no history of orthodontic treatment were collected from the Bolton-Brush Growth Center. Cephalometric images were hand traced, and ODI and APDI values were assessed. Two-sample t tests were used to compare mean ODI and APDI values between African American and white patients; and between male and female African American patients. One-way analysis of variance, followed by the Tukey test, was used to compare mean ODI and APDI values among different African American age and combined age-gender groups.Results:Mean ODI and APDI values were significantly lower (P < .0001) in African American than white patients with normal occlusion and no history of orthodontic treatment. Mean ODI and APDI values increased with age in African American patients, and there were no significant gender differences.Conclusions:The mean ODI and APDI values in 7- to 14-year-old African Americans with normal occlusion and no history of orthodontic treatment were 70.9° and 78.1°, respectively, and were significantly lower than the mean values for white patients in the same age range.     

脑电双频指数监测临床应用的新进展

背景 麻醉深度判断一直是临床医师非常关注的问题.脑电双频指数（bispectral index,BIS）监测是目前应用最为广泛的量化麻醉深度的监测手段,随着BIS监测的普及,其应用价值也不断得到更深入的认识. 目的 就BIS临床应用的新进展作一综述. 内容 术中BIS监测可以使麻醉医师以适合的麻醉深度为目标个体化按需给药,既有助于避免麻醉过浅导致术中知晓,也可避免不必要的麻醉过深而造成的术后恢复延迟,这对于慢性肝病患者的麻醉尤其重要.术中BIS监测有助于通过避免麻醉过深加快患者术后认知功能恢复,并可能改善患者远期预后.对于围术期全脑缺血的高危患者,术中BIS突然下降可能提示脑灌注不足.BIS监测可能还有助于对心跳骤停、心肺复苏后患者的预后判断,但用于预后判断的最佳监测时间和界值仍有待进一步研究阐明. 趋向 术中BIS监测能够预防术中知晓和避免麻醉过深,降低术后谵妄的发生率,并在肝病患者神志判断和麻醉、高危手术围术期脑缺血监测及心肺复苏患者的预后判断等领域有很好的应用价值.     

Two-group classification of patients with obstructive sleep apnea based on analysis of brain recurrence

ObjectiveTo demonstrate that the severity of obstructive sleep apnea (OSA) could be predicted algorithmically by means of recurrence analysis of the sleep-staged electroencephalogram (EEG).MethodsA randomly selected cohort of 20 sleep-staged patients with OSA (apnea–hypopnea index (AHI) 5–30) was divided into mild and moderate sub-cohorts (AHI 5–15, 16–30, respectively), and the sleep EEG (C3) was analyzed using analysis of brain recurrence (ABR) (LSU cohort). Twenty distinct but related markers for sleep depth and fragmentation were computed from four ABR variables, and a marker function capable of classifying each patient into one of the two sub-cohorts was determined by linear discriminant analysis. Classification accuracy of individual patients was evaluated using area under the receiver operator characteristics curve (AUROC). As a control procedure, 20 additional sleep-staged patients with OSA whose polysomnographic data was obtained from an independent database were also evaluated (SHHS cohort).ResultsOn average, markers for sleep depth were reduced and those for sleep fragmentation were increased in the patients with moderate OSA, as expected. All patients in both cohorts were correctly classified using as few as 5–6 markers.SignificanceThe degree of severity of OSA was reflected in objective changes in the sleep EEG. Recurrence analysis of the EEG potentially has uses beyond identification of the degree of OSA.     

胸椎旁神经阻滞术穿刺深度的解剖学研究

目的　观察横突、肋横突外侧韧带与脊神经之间的毗邻关系,为提高超声引导下胸椎旁神经阻滞术的安全性及阻滞效能提供解剖学依据。 方法　选用18具标本胸椎节段,取椎板外侧缘和同名脊神经根的十字交点作为测量的起点,分别测量T1~12共12个节段脊神经与横突下后缘中点、肋横突外侧韧带下缘中点之间的距离。根据“3个一组”原则,12个节段共分为4组,记为T1~3组、T4~6组、T7~9组及T10~12组,对不同组别的脊神经-横突间距、脊神经-肋横突外侧韧带间距分别进行单因素方差分析。 结果　（1）脊神经-横突间距：平均为（16.13±5.59）mm,T1~12总体呈先递增后递减的趋势,T5节段最大,为（18.88±5.78）mm,T5向上或向下节段逐渐减小,T1节段为（16.62±3.67）mm,T12节段为（9.76±3.75）mm。自上而下4组的脊神经-横突间距分别为（17.50±4.67）、（18.19±5.62）、（16.92±5.28）及（12.00±4.42）mm,T10~12组相比T1~3组（P<0.01）、T4~6组（P<0.01）、T7~9组（P<0.01）有统计学差异。（2）脊神经-肋横突外侧韧带间距：平均为（17.67±3.76）mm,自上而下4组的间距分别为（16.95±3.82）、（17.55±3.89）、（17.81±3.83）及（18.30±3.43）mm,两两比较均无统计学差异（P>0.05）。 结论　了解脊神经-横突间距、脊神经-肋横突外侧韧带间距利于估算椎旁神经阻滞的安全穿刺深度,以提高阻滞效能,避免脊神经损伤及全脊髓麻醉的风险。     

牙科即刻种植中不同螺纹形态及深度设计参数种植体的生物力学性能

目的分析牙科即刻种植中不同螺纹形态和螺纹深度种植体周围骨质应力分布情况,为种植体的设计和选择提供依据。方法利用Geomagic Studio、Solid Works和ANSYS Workbench建立下颌骨骨块、种植体及下颌磨牙简化模型,施加垂直载荷和斜向载荷,观察不同螺纹形态和螺纹深度的种植体及其周围骨组织应力分布情况。结果垂直载荷作用下,种植体、皮质骨、松质骨应力峰值变化范围分别为120. 51～129. 63 MPa、9. 94～13. 25 MPa、3. 92～8. 01 MPa,V形、矩形、支撑形、反支撑形种植体周围皮质骨在螺纹深度0. 40～0. 45 mm范围内应力变化平稳;斜向载荷作用下,种植体、皮质骨、松质骨应力峰值变化范围分别为220. 23～286. 51 MPa、33. 39～45. 08 MPa、4. 96～12. 5 MPa。螺纹深度为0. 45 mm,V形、支撑形、反支撑形种植体应力最小。结论 V形、支撑形、反支撑形螺纹种植体选择螺纹深度为0. 45 mm,矩形种植体选择螺纹深度0. 40 mm,呈现出较好的生物力学特性。     

Effect of smoking on immunity in human chronic periodontitis

Aim

Evaluate the effects of smoking on dendritic cells (DCs), cytokines, clinical periodontal parameters, and number of teeth in samples of human chronic periodontitis (CP).

Material and methods

Gingival samples were obtained from 24 smokers and 21 non-smokers with CP. Periodontal examination was carried out. Immunohistochemical staining was performed to identify Factor XIIIa+ immature, CD1a+ immature, and CD83+ mature DCs. The inflammatory infiltrate was counted, and IL-2, IL-10, IL-4, IL-6, IFN-γ, TNF-α, and IL-17A were measured using the cytometric bead array (CBA). Inflammatory infiltrate, DCs, cytokines, classification of CP, clinical periodontal parameters, number of teeth, smoking habit in years (SH/years), and number of cigarettes smoked per day (C/day) were correlated and compared.

Results

CD83+ mature DCs decreased in the smokers group. Negative correlations could be observed between the number of C/day with levels of IL-17A and number of teeth. Correlations between smoking, periodontal disease status, and other cytokines were not observed.

Conclusions

Smoking decreases mature DCs in chronic periodontitis. Moreover, a dose-dependent relation can be observed between C/day and number of teeth and levels of IL17A observed. Smokers show a different modulation of the CP immune response.     

Factors associated with the clinical response to nonsurgical periodontal therapy in people with type 2 diabetes mellitus

BackgroundType 2 diabetes mellitus (T2DM) is a growing health problem worldwide. People with T2DM are at risk of experiencing periodontitis and likely require treatment. Using data from the national multicenter Diabetes and Periodontal Therapy Trial (DPTT), the authors assessed patient-based characteristics associated with the clinical response to nonsurgical therapy.MethodsThe DPTT investigators randomly assigned adults with T2DM (hemoglobin A_1c [HbA_1c] ≥ 7 percent and < 9 percent) and moderate to advanced periodontitis to receive immediate or delayed therapy (scaling and root planing, oral hygiene instruction, chlorhexidine rinse). The investigators assessed probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), and medical conditions at baseline, three months and six months. Six-month changes in mean PD, CAL and BOP defined the treatment response. Complete data were available for 473 of 514 DPTT participants. The authors used multiple regression models to evaluate participant-level factors associated with the response.ResultsMore severe baseline PD, CAL and BOP were associated with greater improvements in these same measurements (P < .0001). Hispanic participants experienced greater improvements in PD and CAL than did non-Hispanic participants (P < .0001). Obese participants (those with a body mass index > 30 kilograms per square meter) experienced greater reductions in PD and BOP than did participants who were not obese (P < .001). Age, sex, HbA_1c values, diabetes duration, and smoking were not associated with change in any outcome (P > .1).ConclusionsIn patients with T2DM, baseline disease severity was associated with the clinical response to nonsurgical periodontal therapy. Body mass index and Hispanic ethnicity—but not glycemic control, diabetes duration or smoking—also may be useful in predicting clinical changes in this population.Practical ImplicationsThese findings could help clinicians identify patients with T2DM who may or may not respond well to initial periodontal treatment.     

In-vitro accuracy and reproducibility evaluation of probing depth measurements of selected periodontal probes

AimThe purpose of the present in vitro study was to measure the accuracy and reproducibility of three periodontal probes. To eliminate environment- or examiner-related probing errors, two aluminum blocks with predrilled holes of varying depths were examined by participants who had been trained in probing before the study. This methodology improved the likelihood that any probing errors identified were generated by the probes themselves.Materials and methodsThree probes, Williams 14 W (Hu-Friedy Mfg. Co., LLC, UK), Chapple UB-CF-15 (Implantium, Shrewsbury, UK), and Vivacare TPS (Ivoclar Vivadent, Enderby, UK), were randomly distributed to 23 participants (9 males and 14 females; mean age: 31.35 years). Participants measured 30 holes in two aluminum blocks, average 20 days, SD = 341.05. For each hole, the mean measured depth was calculated for each participant and compared to the true depth. Intra- and inter-examiner accuracy and reproducibility for each of the duplicate measurements were calculated. Data were analyzed by paired-samples t-test with the SPSS 18 software package (IBM Portsmouth, UK). A p-value <0.05 indicated statistical significance. Tables were constructed from the data.ResultsWhen used by participants, the Williams 14 W probe was reproducible but not necessarily accurate; Vivacare TPS was neither accurate nor reproducible; and Chapple UBCF-15 was both accurate and reproducible.ConclusionDepth measurements with the Chapple UB-CF-15 probe were more accurate and reproducible compared to measurements with the Vivacare TPS and Williams 14 W probes. This in vitro model may be useful for intra-examiner calibration or clinician training prior to the clinical evaluation of patients or in longitudinal studies involving periodontal evaluation.     

Stereoscopic depth constancy for physical objects and their virtual counterparts

Stereopsis plays an important role in depth perception; if so, disparity-defined depth should not vary with distance. However, studies of stereoscopic depth constancy often report systematic distortions in depth judgments over distance, particularly for virtual stimuli. Our aim was to understand how depth estimation is impacted by viewing distance and display-based cue conflicts by replicating physical objects in virtual counterparts. To this end, we measured perceived depth using virtual textured half-cylinders and identical three-dimensional (3D) printed versions at two viewing distances under monocular and binocular conditions. Virtual stimuli were viewed using a mirror stereoscope and an Oculus Rift head-mounted display (HMD), while physical stimuli were viewed in a controlled test environment. Depth judgments were similar in both virtual apparatuses, which suggests that variations in the viewing geometry and optics of the HMD have little impact on perceived depth. When viewing physical stimuli binocularly, judgments were accurate and exhibited stereoscopic depth constancy. However, in all cases, depth was underestimated for virtual stimuli and failed to achieve depth constancy. It is clear that depth constancy is only complete for cue-rich physical stimuli and that the failure of constancy in virtual stimuli is due to the presence of the vergence-accommodation conflict. Further, our post hoc analysis revealed that prior experience with virtual and physical environments had a strong effect on depth judgments. That is, performance in virtual environments was enhanced by limited exposure to a related task using physical objects.     

Simulation of Depth of Wear of Eco-Friendly Concrete Using Machine Learning Based Computational Approaches

To avoid time-consuming, costly, and laborious experimental tests that require skilled personnel, an effort has been made to formulate the depth of wear of fly-ash concrete using a comparative study of machine learning techniques, namely random forest regression (RFR) and gene expression programming (GEP). A widespread database comprising 216 experimental records was constructed from available research. The database includes depth of wear as a response parameter and nine different explanatory variables, i.e., cement content, fly ash, water content, fine and coarse aggregate, plasticizer, air-entraining agent, age of concrete, and time of testing. The performance of the models was judged via statistical metrics. The GEP model gives better performance with R² and ρ equals 0.9667 and 0.0501 respectively and meet with the external validation criterion suggested in the previous literature. The k-fold cross-validation also verifies the accurateness of the model by evaluating R², RSE, MAE, and RMSE. The sensitivity analysis of GEP equation indicated that the time of testing is the influential parameter. The results of this research can help the designers, practitioners, and researchers to quickly estimate the depth of wear of fly-ash concrete thus shortening its ecological susceptibilities that push to sustainable and faster construction from the viewpoint of environmentally friendly waste management.