Effect of masticating chewing gum on postural stability during upright standing

The purpose of this study was to investigate the effect of masticating chewing gum on postural stability during upright standing. To address this issue, 12 healthy subjects performed quiet standing on a force platform for the posturography study. The subjects were instructed to stand as stable as possible on the force platform in order to record the trajectory of the center-of-pressure (COP). After measuring the postural sway in the initial condition (pre-condition), the subjects were asked to stand while masticating chewing gum (gum-condition). Following the gum-condition, quiet standing without mastication was evaluated (post-condition) to ensure the effect of masticating chewing gum on postural stability. The trajectory and velocity of the COP were analyzed for each condition. We found that the postural stability tended to enhance during mastication of chewing gum. The rectangle area of the COP trajectory significantly diminished in the gum-condition and significantly enlarged in the post-condition. A similar effect was observed in the maximum velocity and standard deviation (SD) of the fore-aft amplitude of the COP trajectory. The values were significantly smaller in the gum-condition compared to those in the post-condition. These findings suggest that mastication of chewing gum affects the postural control by enhancing the postural stability during upright standing.     

Task-induced activation and hemispheric dominance in cerebral circulation during gum chewing

In elderly persons, it is thought that maintenance of masticatory function may have a beneficial effect on maintenance of cerebral function. However, few studies on cerebral circulation during mastication exist. This study aimed to verify a possible increase in cerebral circulation and the presence of cerebral hemispheric dominance during gum chewing. Twelve healthy, young right-handed subjects with normal dentition were enrolled. Bilateral middle cerebral arterial blood flow velocities (MCAV), heart rate, and arterial carbon dioxide levels were measured during a handgrip exercise and gum chewing. During gum chewing, electromyography of the bilateral masseter muscle was recorded.MCAV and heart rate significantly increased during exercise compared to values at rest.During gum chewing, there were no differences in the rate of increase in MCAV between the working and non-working sides, but during the handgrip exercise, the rate of increase in MCAV was significantly greater for the non-working side than for the working side.During gum chewing,muscle activity on the working side was significantly greater than that on the non-working side. These results suggest that during gum chewing, cerebral circulation increases bilaterally and does not show contralateral dominance, as it does during the handgrip exercise.     

利巴韦林温度-离子敏感型鼻用原位凝胶喷雾剂的制备及体外性质考察

目的制备具有适宜临界相变温度和临界相变阳离子强度,及适宜的喷雾粒度、使用方便、缓慢释放药物的温度-离子敏感复合型鼻用原位凝胶。方法以临界相变温度、临界相变阳离子强度、喷雾粒度为考察指标筛选温敏及离子敏材料的用量,制备利巴韦林温度-离子敏感复合型原位凝胶。以透析袋法评价该复合凝胶的凝胶外排水量、溶蚀速率、体外释放度,并以断裂距离为指标评价凝胶的黏膜黏附力。结果以质量分数为0.3%的去乙酰化结冷胶和质量分数为18.0%的泊洛沙姆407制备的温度-离子敏感复合型原位凝胶,临界相变温度为32.6℃,临界相变阳离子强度为93.4 mmol.kg-1,喷雾粒度为68.0μm,凝胶外排水质量分数为(13.8±0.8)%,溶蚀速度常数为1×10-4min-1,断裂距离为(1.60±0.06)mm。该混合凝胶具有良好的体外缓释特征。结论该复合型原位凝胶剂适宜作为水溶性药物的鼻用缓释载体。     

麦芽糖醇口香糖对口腔三种致龋菌的抑制作用

目的:探讨麦芽糖醇口香糖对口腔中3 种致龋菌的抑制效果.方法: 将30 名13～15 岁龋易感儿童随机分为3 组,即麦芽糖醇口香糖组(A组)、木糖醇口香糖组(B组)、空白胶母口香糖组(C组).咀嚼口香糖前后共收集2 次牙菌斑,运用平板法进行牙菌斑中细菌培养计数观察咀嚼口香糖前后3 种致龋菌(变链、乳杆、黏放)数量的变化.结果: 与咀嚼前相比,咀嚼口香糖4 周后A、B、C 3 组变链、乳杆、黏放致龋菌数量均呈下降趋势(P<0.001);与C组相比,咀嚼口香糖4 周后A、B 2 组更能显著降低变链数量(P<0.05);3 组间乳杆菌数量和黏放数量的下降无统计学差异(P>0.05).结论:麦芽糖醇口香糖抑制牙菌斑内变链菌数量较为明显,对乳杆菌、黏放菌的抑制作用则不明显.     

Masticatory Performance and Chewing Cycle Kinematics—Are They Related?

Objective:To compare chewing cycle kinematics of subjects with better and poorer masticatory performance.Materials and Methods:A cross-sectional study compared masticatory performance, based on the breakdown of the artificial test food Cuttersil®, in 30 subjects with Class I occlusion. Individuals with median particle sizes greater and lesser than the median value for the entire sample were categorized as poorer (15) and better (15) performers, respectively. While chewing Cuttersil, three-dimensional jaw movements of subjects were tracked with an optoelectric computer system. Multilevel linear modeling was used to evaluate differences in estimated cycle shape, cycle duration, and maximum excursions, as well as within-subject variation between the two groups.Results:Poorer performers had a significantly longer opening duration (0.274 ± 0.225 sec vs 0.325 ± 0.270 sec) than better performers. Poorer and better performers also showed significant differences in cycle shape, including a less horizontal path of closure and more posterior jaw movement in the poorer performers. In addition, poorer performers exhibited significantly more cycle-to-cycle (within-subject) variability in chewing cycle duration, excursive movements, and lateral velocity than did better performers.Conclusions:Poorer performers lacked consistency in their chewing cycles, and their cycle shape differs from that of better performers.     

长角豆胶对小鼠糖代谢的影响

<正>半乳甘露聚糖是植物的储备性多糖,主要存在于豆科植物种子的胚乳中,具有较强的吸水和保水能力,可作为增稠剂、凝胶剂、稳定剂和凝聚剂等广泛应用于食品、医药等许多工业领域[1]。     

The Antibacterial Effect of CMCTS-Containing Chewing Gum

Objective:This paper was designed to confirm the efficacy of chewing carboxymethyl chitosan(CMCTS)-containing gum in suppressing the growth of oral bacteria when compared to a CMCTS-containing mouth rinse.Methods:Fourteen healthy subjects were recruited from among the staff and students of Qingdao University Dentistry Department.Before the experiments saliva was collected from all subjects and bacteria counts determined.For the gum study,the subjects chewed CMCTS-containing gum for 5 rain and then rested for 5 min.When testing the CMCTS mouth rinse,the subjects gargled with 10 mL of solution for 30 s,followed by resting for 9min 30 s.These protocols were repeated five times over a 50 rain period on the same day.Post-experiment saliva samples were then collected at the following times:0,30 and 60 min.Results:Chewing gum containing CMCTS or rinsing with a CMCTS-containing rinse significantly decreased oral bacteria counts.The total bacteria counts,total Streptococci counts,and mutans streptococci counts of saliva from subjects who chewed CMCTS-containing gum were significantly lower than saliva from subjects in the rinse group in all three sampling periods,except in the case of the total bacteria count in the 60 min samples.Conclusion:CMCTS-containing gum chewing has a greater antibac-terial effect than using a CMCTS-containing mouth rinse.The present findings strongly indicate that the application of natural materials such as chitosan and its derivatives is useful for better oral health.     

咀嚼口香糖对剖宫产术后产妇胃肠功能影响的Meta分析

目的：通过Meta分析,探讨咀嚼口香糖对剖宫产孕妇术后胃肠功能恢复的影响。方法：计算机检索PubMed、Cochrane Library、Embase、Medline、中国生物医学文献数据库（CBM）、维普数据库、万方数据库和中国知网等数据库中关于咀嚼口香糖和剖宫产术后胃肠功能恢复的随机对照研究。在文献筛选、提取数据、纳入文献质量评价后,运用Stata 14.0软件进行数据分析。结果：本研究共纳入27篇随机对照研究,其中中文文献6篇,英文文献21篇,共计4 008例患者,其中试验组1 983例、对照组2 025例。Meta分析结果表明,与对照组相比,试验组可有效促进剖宫产术后肠鸣音（WMD=-5.30,95%CI：-7.14~-3.46,P<0.000 1）及胃肠蠕动（SMD=-3.82,95%CI：-5.15~-2.49,P<0.000 1）的恢复,缩短肛门排气（WMD=-6.90,95%CI：-8.96~-4.85,P<0.000 1）及排便时间（WMD=-7.64,95%CI：-10.59~-4.69,P<0.000 1）,减少术后肠梗阻发生率（RR=0.15,95%CI：0.10~0.22,P<0.000 1）及患者住院时间（SMD=-0.73,95%CI：-1.11~-0.34,P<0.000 1）。结论：剖宫产术后咀嚼口香糖可有效促进胃肠功能的早期恢复,但纳入研究间异质性差异较为明显,未来需要更多标准化、多中心、大样本和高质量的临床研究来进一步验证。     

Oral mutans streptococci levels following use of a xylitol mouth rinse: a double‐blind,randomized, controlled clinical trial

Xylitol‐sweetened chewing gum has cariostatic properties, but is not suitable for all patients. This study evaluated the effect of xylitol rinse on mutans streptococci (MS) levels in the mouth. One hundred and five subjects with high salivary MS levels were randomly assigned to one of three groups. Subjects in the positive control group (N = 35) chewed two xylitol gum pellets for at least 5 minutes three times daily (xylitol dose: 4.3g/day). The experimental group (N = 36) rinsed with 20 mL of an aqueous solution of xylitol twice daily for 60 seconds (dose: 4.4g/day). The negative control group (N = 34) used neither product. No attempt was made to change the subjects’ diet. Mean MS levels at baseline were 5.6 (0.1) in positive control, 5.4 (0.1) in experimental, and 5.5 (0.1) in negative control groups. After 3 months, MS levels were 4.4 (0.2), 4.4 (0.2), and 4.9 (0.2), respectively. Differences between groups were not significant by ANOVA (p = .2); however, MS levels tended to be lower in the experimental and positive control groups. Xylitol rinse and chewing gum caused a similar but statistically insignificant reduction in MS levels in the mouth.