Jaw Bone Health
Teeth are held in place by bones of the upper and lower jaw. Bone can be lost due to gum disease, missing teeth or pathology like cyst or tumors in the jaw. The jaw bone is alive and remodels according to function. Just like a muscle, bone needs to be exercised through the motions of the teeth to maintain its shape. Chewing and biting stimulates the bone to maintain its bulk. When a tooth is lost, and no force is applied to the bone it resorbs and becomes smaller and thinner.
Consequences of Bone Loss and Missing Teeth
Teeth have the tendency to shift towards the midline. They also have the tendency to erupt if nothing is opposing. When a tooth is lost, the one behind it can tip towards the empty space and the opposing tooth can start erupting. This can lead to misalignment of teeth as well as loosening of the opposing tooth which can lead to loss of the opposing tooth as well.
Loss of front teeth and bone can cause support of the lips, which can lead to wrinkling of the lips and skin around the mouth.
When posterior or back teeth such as molars a lost, the bite can collapse and overclose. This can lead to overloading of the jaw joint. When the joint is chronically overloaded it can lead to arthritis and chronic pain.
Loss of Anterior teeth can create difficulty in pronouncing words and speaking. The tongue, muscles of the lips and teeth work together to create words.
The ability to chew property has a direct correlation to nutritional intake.
Bone loss of the Jaw
Why did I lose my bone is the most common questions that patients have. Here are some of the most common reasons.
Just like exercise stimulate the muscles the pressure and forces of the teeth stimulate the bone. After a tooth is extracted or lost, the jaw bone has no need to keep up its bulk and shape. Overtime it collapses. This happens most rapidly in the first year after tooth loss especially in the upper jaw anterior region.
Periodontal or Gum disease is a slow silent disease that destroys bone that supports the teeth. Plaque and Calculus causes inflammation of the gum. The space or pocekts between the swollen gum and the teeth trap food and cause bacteria to reside and release toxins that irritate the gum even further leading to bone loss and gum tissue loss. When there is no more support for the teeth, the teeth become loose.
Dentures and Bridges
Unlike teeth or implants, dentures and bridges are not anchored directly to the bone. Dentures sit on top of the bone and apply pressure to the bone. This pressure further resorbs bone. A bridge is anchored to the adjacent neighboring teeth. Because it has to compensate for the pressure of the missing teeth, the adjacent teeth can become weaker over time. When one of the supporting teeth of the bridge breakdown, the missing tooth space and the broken tooth have to be addressed. If the bridge was in place for a long time, the missing tooth space usually has extensive bone loss because of lack of stimulation.
Sports related accidents are the most common cause to knock out front teeth. The injury can be limited to part of the tooth or if extensive it can lead to fracture of the supporting bone. Teeth can get knocked out (avulsion) and fractured. When the bone is injured, it can resorb and lead to bone loss.
Tumors and Cysts
Tumors and cysts related to teeth can cause bone resorption. Impacted wisdom teeth and upper canines commonly have associated cyst and tumors. The enlargement of a cyst or tumor can cause resorption of the existing bone that can lead to loosening of neighboring teeth. If the bone loss is extensive, it can even lead to fractures of the jaw. Grafting can be necessary in order to preserve the integrity of the jaw.
When posterior upper jaw (Maxilla) teeth are lost the pressure of the air cavity can enarge and resorp the bone called pneumatization of the sinus. The sinus is lined by a membrance which is thin lining that looks like an egg shell lining. When there are no teeth in the bone, the air pressure can cause resorption. In order to create space, the membrane can be lifted and bone can be placed to tent up the sinus membrane and this is called a Sinus Lift.