Can Masticatory Electromyography be Normalised to Submaximal Bite Force?

The combination of bite force and jaw muscle electromyography (EMG) provides an insight into the performance of the stomatognathic system, especially in relation to dynamic movement tasks. Literature has extensively investigated possible methods for normalising EMG data encapsulating many different approaches. However, bite force literature trends towards normalising EMG to a maximal voluntary contraction (MVC), which could be difficult for ageing populations or those with poor dental health or limiting conditions such as temporomandibular disorder. The objectives of this study were to (i) determine whether jaw‐closing muscle activity is linearly correlated with incremental submaximal and maximal bite force levels and (ii) assess whether normalising maximal and submaximal muscle activity to that produced when performing a low submaximal bite force (20 N) improves repeatability of EMG values. Thirty healthy adults (15 men, 15 women; mean age 21 ± 1·2 years) had bite force measurements obtained using a custom‐made button strain gauge load cell. Masseter and anterior temporalis muscle activities were collected bilaterally using surface EMG sensors whilst participants performed maximal biting and three levels of submaximal biting. Furthermore, a small group (n = 4 females) were retested for reliability purposes. Coefficients of variation and intra‐class correlation coefficients showed markedly improved reliability when EMG data were normalised compared to non‐normalised. This study shows that jaw muscle EMG may be successfully normalised to a very low bite force. This may open possibilities for comparisons between at‐risk sample groups that may otherwise find it difficult to produce maximal bite force values.     

Bite turbo配合早期牵引治疗前牙反牙合的疗效分析

目的分析Bite turbo配合早期Ⅲ类牵引治疗前牙反牙合的临床效果。方法 16例恒牙期前牙反牙合且反覆牙合深的病例,下前牙舌侧粘接Bite turbo,并同时进行早期Ⅲ类牵引,观察其疗程及疗效。结果 16例病例均快速打开咬合并解除前牙反牙合。咬合打开后SNB减小、ANB增大,下颌平面角、下面高、下面高/全面高增大,上下磨牙均伸长、下切牙被压低,反覆盖解除,覆牙合减小。结论 Bite turbo配合早期Ⅲ类牵引可以快速打开咬合,解除前牙反牙合。     

Education, education, disillusion?

Between the end of 2009 and 2010, the General Dental Council (GDC) changed and the part appointed, part elected body which had been in place since its inception in 1957 became fully appointed. Since then, various quite radical departures in terms of its committee structure and proposals for the education and training of dental professionals have emerged. This paper reviews these developments in the wider context of the Council's role, recent record and overall accountability.     

自锁矫治技术结合Bite Turbo矫治青少年深覆牙合的临床研究

目的探讨分析自锁矫治技术结合Bite Turbo矫治青少年前牙深覆牙合的临床效果。方法从我院正畸科选择深覆牙合青少年患者22例,随机分为实验组和对照组,各11例。实验组:自锁矫治器+Bite Turbo;对照组:自锁矫治器+平面导板。对比两组的临床疗效,进行咬合打开前后的模型测量分析、X线头影测量分析。结果实验组覆牙合平均减小3.45mm,咬合完全打开平均2.10个月,对照组覆牙合平均减小3.10mm,咬合完全打开平均4.25个月,统计学分析有显著性差异(P<0.05);两组治疗后其颌骨变化统计学分析无显著性差异(P>0.05)。结论 Bite Turbo应用于自锁矫治技术中治疗青少年深覆牙合,具有便捷易行、卫生高效、缩短正畸整体疗程等明显优势,是一种值得临床推广的矫正方法。     

Quo vadis,Kreditzins?

Der Freie Zahnarzt -     

Decoronation: how, why, and when?

Decoronation is a surgical method for treating ankylosed incisors in children and adolescents. The crown and root filling are removed, leaving the root in situ to be resorbed and covered with a mucoperiosteal flap. Early loss of a permanent tooth leads to loss of alveolar bone, especially in buccopalatal width. Decoronation preserves not only the width of the ridge but also the vertical height.     

Cancer, what is it?

Cancer is characterized by the independent growth of cells based on a series of genetic defects. These include changes in proto-oncogenes and tumor suppressor-genes and are based on both pre-existent and acquired alterations in the genome of the cell, caused by exogenous and endogenous factors. The development of cancer is not dependent on a single genetic hit, but requires a series of subsequent alterations. A growing tumour forms its own infrastructure consisting of stroma and blood vessels. Furthermore, the presence of a mononuclear infiltrate indicates an interaction with the immune system. Due to an unbalance between the production and disappearance of cells in a given tissue a growing tumour is born from where cells escape that are capable to penetrate through a basal membrane and that can metastasize to various organs. The increased knowledge regarding the biology of cancer opens new ways for cancer treatment such as gene therapy, immunotherapy and the application of inhibitors of neoangiogenesis.