(Greek, ismos; Latin, ismus: a suffix: belief in, practice of, condition of, process, characteristic behavior or manner, abnormal state, distinctive feature or trait)
2. The unconscious habit of grinding or gritting the teeth that occurs during sleep or in stressful situations and can lead to excessive wear of the teeth.
3. Bruxism is due to clenching of the teeth other than in chewing and is associated with forceful lateral or protrusive jaw movements. This results in the grinding or rubbing of the teeth together.
Bruxism usually occurs during sleep
Bruxers involuntarily gnash their teeth either during sleep, or unconsciously during waking hours. This stressful grinding of th teeth exerts thousands of pounds of pressure on the teeth surfaces and can severely damage the teeth, the gums, and the jawbones.
During bruxism episodes, there is no food to cushion the blows of the teeth colliding against each other. Bruxism, therefore, can upset the delicate pressure balance of teeth, wearing down the ridges of tooth enamel and loosening or moving teeth from their proper positions.
All of this grinding and clenching of teeth can cause facial muscles to ache or tighten up with sharp pain. This can lead to pain and clicking or cracking sounds in the joints of the jawbones and a severe headache.
Gum diseases may be aggravated by bruxism to the extent that the bone supporting the teeth is lost and they become loosened and fall out.
It is sometimes done to such an excess that it damages the occlusal surfaces of the teeth, particularly the molar teeth, and may contribute to the temporomandibular joint (TMJ) syndrome.
The temporomandibular joint (TMJ) is the area directly in front of the ear on either side of the head where the upper jaw (maxilla) and lower jaw (mandible) meet.
Within the TMJ there are moving parts that allow the upper jaw to close on the lower jaw. This joint is a typical sliding "ball and socket" which has a disc sandwiched between it.
The TMJ is used many hundreds of times a day in moving the jaw, biting and chewing, talking and yawning. It is one of the most frequently used of all the joints in the body.
The temporomandibular joints are complex and are composed of muscles, tendons, and bones. Each component contributes to the smooth operation of the TMJ.
When the muscles are relaxed and balanced and both jaw joints open and close comfortably, we are able to talk, chew, or yawn without pain.
2. An economic system based on the private ownership of the means of production and distribution of goods, characterized by a free competitive market and motivation by profit.
2. Etymology: from Latin caper, "goat", + loquor, "to speak".
2. Prepubescent castration.
2. A chemical property or relationship.
2. An orientation response to a chemical stimulus.
2. A condition or state of containing two or more genetically distinct cell types.
In humans, chimerism results from any organ transplant other than that between identical twins or from the mixture of blood cells between dizygous twins (either of two twins who developed from two separate fertilized eggs) in the uterus before birth.
A dizygotic twin refers to either of the "fraternal" twins who has shared a common uterine environment with its twin which is a result of a different fertilized ovum.