The Valsalva maneuver is a simple technique that involves breathing out of the nose and mouth while they are closed. This raises the pressure inside the chest and middle ear, and can equalize pressure in the ears and help reduce some heart arrhythmias. Although rare, ear damage can sometimes occur when blowing too hard with the Valsalva maneuver. Ear “popping” sensations are usually felt at the start of the Valsalva maneuver, but to also get the cardiac benefits, the maneuver must continue for 10-15 seconds. The modified Valsalva maneuver involves laying flat with the legs elevated for 15 seconds after exhaling against closed airways for 15 seconds. This modification improves the heart rate in patients with certain types of arrhythmias, and it can be done anytime, anywhere — nothing is needed to perform the Valsalva maneuver. SVT, or supraventricular tachycardia, is a type of fast heart beat that can sometimes be serious and requires medical treatment.
Variance is a measure of statistical dispersion about the mean. The larger the variance, the further individual values of the random variable (observations) tend to be from the mean, or average. Variance exists between individuals of a species for a multitude of traits, including dentition. A number of different genetic, environmental, and mechanical factors may be at the root of this variance. Even in cases of monozygotic twins, dental variation is seen in their individual dentition. This may be due to epigenetic factors, environmental variances, and different phylogenetic influences. Variance in dentistry can also be found in the measurements taken by different tools. Each tool used is calibrated per industry standards but subtle differences in each individual tool will result in minor, or sometimes major, variances. Careful calibration prior to use, proper tool cleaning and maintenance, and proper tool storage and care will help diminish the likelihood of extreme variance between tools.
Vascular endothelial growth factor (VEGF), also called vascular permeability factor (VPF), is a specific type of protein known as a signal protein that encourages the body’s creation of blood vessels. When cells release this protein, it “signals” the body to take action — in the case of VEGF, either by angiogenesis or vasculogenesis. Angiogenesis is the creation of new blood vessels from existing vasculature, while vasculogenesis is the creation of the circulatory system in the embryo. The vascular endothelial growth factor protein is critical to human survival as it’s the protein that restores the supply of oxygen to tissues that have become hypoxic, or suffered a loss of oxygen. Most often, this occurs after cells become injured or to repair muscle after exercise. However, VEGF expression can also result in the formation of new blood vessels to circumvent ones that are blocked, a process called collateral circulation. Overexpression of VEGF can lead to disease.
All parts of the body require oxygen to function, which is carried to the cells via blood vessels or the vascular supply. The heart and lungs require a great deal of oxygen, while other parts of the body, like bone, require less. However, bone can also cease to function without an adequate supply of oxygen. In an average long bone, oxygenated blood is supplied by either periosteal vessels, epiphyseal vessels, or a nutrient artery. By having three systems in place, one can take over the function of the other if it becomes blocked or damaged in some way. If bone tissue does not receive enough oxygen, a process known as avascular necrosis or osteonecrosis occurs. This is the death or decay of the bone due to a lack of oxygenated blood. Osteonecrosis can cause the bone to become brittle, breaking into small pieces and eventually crumbling or collapsing if left untreated.
Veneers are one of the most common cosmetic dental procedures performed in the U.S. A veneer is a thin piece of porcelain (and less commonly, resin) that is placed over the front of a tooth to restore its size, shape, and color. Dental veneers can be used to correct a wide variety of cosmetic issues, including broken or chipped teeth, teeth gaps, and stained or severely discolored teeth. Veneers are permanent because the natural tooth must be altered or filed down to adhere the veneer using dental cement. While a patient can have a single veneer placed, most often, patients interested in significant restoration will have multiple veneers put on. Veneers give teeth the smooth, shiny, uniform look that celebrities often have; this is usually because they also have veneers. Patients can choose bright, white veneers or veneers with a more natural color to achieve their aesthetic goals.
Before manufacturing the prosthetic framework for multiple dental implants, it’s important that periodontists ensure that the framework has the optimal passive seat. To do this, a verification jig is often used. This ensures that the master model is precise before the framework is created. A verification jig mimics the fit of the final restoration framework so the model accuracy can be verified to confirm that the end restoration fits perfectly. The jig is made of temporary cylinders that are joined together with a stiff resinous material and often, rods or sturdy wires. Then, the jig is placed over all of the dental implants in the patient’s mouth; an unstable frame means that the screws need to be adjusted on either side to prevent movement of the jig. The jig can be used for the final framework once all rocking or movement in the mouth has ceased.
The vertical dimension of occlusion (VDO), is the measurement of the relationship between the upper and lower jaw when the teeth are fully occluded in max intercuspation. VDO is sometimes referred to as vertical dimension or occlusal vertical dimension (OVD). Both patients with and without teeth possess a VDO, however, the latter is more subjective in measurement and is generally based on esthetics and phonetics, or the sound of words being pronounced as the jaw is held in the desired position. The vertical dimension of occlusion can roughly be measured by asking the patient to say “Emma.” The position of the lower jaw on the “a” sound is called the vertical dimension at rest (VDR), which is roughly 3mm greater than a patient’s VDO. Reduction of the vertical dimension of occlusion can occur after tooth loss, tooth decay, gum disease, and loss of bone in the alveolar ridge.
Vertical dimension of occlusion (VDO), also known as occlusal vertical dimension (OVD), is a term used in dentistry to indicate the superior-inferior relationship of the maxilla and the mandible when the teeth or wax rims are situated in maximum intercuspation or contact. In dental applications, the vertical dimension of occlusion is an important measurement in determining the correct dimensions for a prosthesis. In oral trauma, the proper vertical dimension of occlusion for the patient must be known so the correct basal bone height reconstruction can be achieved. An increase in basal bone height will reduce the VDO and can lead to problems including speech difficulties, unnatural lip contact, esthetic issues, and temporomandibular joint pain complications. A decrease in basal bone height will also cause issues including drooling of saliva, improper contact of the upper and lower teeth, and injuries to the soft tissue of the cheek due to accidental biting.