The influence of orthognathic surgery on ventilation during sleep.

Orthognathic surgery has varying effects on respiratory parameters. The authors undertook a prospective study of patients requiring mandibular advancement, mandibular setback and maxillary Le Fort I advancement, and surgically assisted rapid maxillary expansion (SARME). Breathing parameters were monitored in a sleep laboratory the night before the operation and in a mean of 9.5 months after the operation. In patients treated with mandibular advancement, the respiratory disturbance index (RDI), oxygen desaturation index (ODI), and number of obstructive apnoeas (OAs) improved significantly. In patients treated with mandibular setback and maxillary Le Fort I advancement, the RDI, ODI, index of flow limitations (IFL), number of obstructive hypopnoeas (OHs), OA, and oxygen saturation deteriorated. In contrast, patients treated with SARME improved only mildly. These results indicate that bimaxillary surgery for Class III malocclusion increased upper airway resistance, probably because of a more dorsal positioning of the base of the tongue, representing an iatrogenic obstructive sleep apnoea (OSA). A young person would probably be able to balance such a decline in respiratory function using different adaptative mechanisms. Mandibular advancement significantly improved respiratory parameters during sleep. The possible effect of orthognathic surgery on the upper airways should be incorporated into the treatment plan.

Reduction of the negative influence of patient motion on quality of CBCT scan.

The role of cone beam computed tomography (CBCT) in imaging of the oral and maxillofacial region is well known and its indications and possibilities are still increasing. More sophisticated technologies are being developed each year, mainly providing higher resolution, bigger field of view, faster scanning and better scatter reduction. One of the major problems remaining to be solved is the unwanted movement of the patient during the scanning procedure. All hardware solutions that have been developed to fix the patient's head in a steady position have their limits. For example, they cannot eliminate small movements caused by breathing, heartbeat, and swallowing. We have developed a simple method to improve these CBCT images. The movement of the scanned object is monitored with marks attached to it. These marks are identified on every 2D image captured during the scanning procedure and used to unify the position of these 2D images. The final 3D reconstruction produces a sharper 3D data set with higher resolution and reduced blur. In conclusion, this simple method has the potential to improve the quality of CBCT scans.

Mechanism of increased mortality in hemodialysed patients with periodontitis.

Periodontitis significantly decreases survival in hemodialysed patients with end stage renal disease (ESRD). Periodontitis-related microorganisms spreading into the bloodstream are thought to impair blood rheological parameters - for example, increasing whole blood viscosity, aggregating blood elements, and decreasing blood flow - and thereby significantly accelerate systemic or local diseases, impairing survival. We discuss the ability of a prototypical pathogenic anaerobic polybacterial consortium to modulate and interfere with host immune responses and to enzymatically degrade host proteins, to bind to and cleave extracellular matrix proteins, to invade intercellularly as well as intracellularly, to promote vascular permeability, to disrupt polymorphonuclear leukocyte function, to cleave complement, and to degrade IgG heavy chains. To further elucidate these phenomena, studies involving detecting microorganism byproducts and monitoring blood rheological parameters are necessary.

Myosin heavy chain proteins are responsible for the development of obstructive sleep apnea syndrome.

We introduce a hypothesis that obstructive sleep apnea syndrome (OSAS) is primarily caused by an inherited reduced adaptability of upper airway striated muscles such that they cannot maintain patency when there is reduced consciousness (sleep). This reduced ability is caused by a deficiency of the genes for specific myosin heavy chain (MHC) proteins, which are the primary source of muscle adaptability in adults and were initially described in the chewing muscles. The development of OSAS must be linked to problems with striated muscle because affected patients are capable of normal breathing when awake but their respiratory parameters deteriorate during sleep; OSAS must, therefore, be caused by a factor that is voluntarily active during waking but inactive during sleep, and this can only be striated muscle. Congenital or acquired anatomical abnormalities are involved only partially, because OSAS patients with anatomical abnormalities do not begin to snore or to have apneas or hypopneas when lying in bed awake, but begin to do so only when sleeping.