DENTAL IMPLANTS AND BONE GRAFTSDental implants have become a increasingly popular option to replace missing teeth. But before your general dentist, periodontist, or oral surgeon places a dental implant to replace one or more missing teeth, a bone graft may be required prior to the placement of the implant. It may sound a little intimidating at first, but bone grafts are in general a very predictable, painless, and routine part of dental care.
WHAT IS A BONE GRAFT?As we age and get older, our oral soft and hard tissue structures change. Specifically gingival and bone structures supporting where teeth were once present and now missing, atrophies and becomes smaller. A predominant reason why our jaws have the current density and amount of bone they do is due to the presence of existing teeth. With teeth in support and in constant function, it stimulates the bone and allows continuous bone regeneration and prevents bone from degeneration. Without teeth to support the adjacent bone, the jaw bone atrophies and degenerates to a basal bone level.
Most jaw bone will atrophy within the first year and a half after the tooth is initially missing, and will then continue to undergo bone loss at a indefinite slow rate. For patients with total complete loss of teeth, this usually results in a very thin ridge of bone in the lower jaw (mandible); for the upper jaw (maxilla) the results are less pronounced.
BONE GRAFT HISTORYIn the past, bone grafts were frequently done in a hospital setting. It was not uncommon for surgeons to use a patient's ribs or hip bone to increase lower jaw size. Sometimes skin grafts were also taken from a patient's thigh and placed inside the mouth to prevent the tissues from moving the denture while patient is talking and chewing. Fortunately with modern research and technology, a more preventive and contemporary approach has made the dental implant procedure less invasive and more minimalistic.
WHAT CAN CAUSE BONE LOSS THAT MAKES BONE GRAFT NECESSARY?Potential bone loss causes within the oral cavity may include the following below:
- Tooth Extraction - In cases where it is a dental and medical necessity to remove a permanent adult tooth, bone loss within the jaw can happen if the tooth is not replaced with an implant.
- Sinus Deficiency - Whereas in cases where a molar is removed from the upper jaw (maxilla), air pressure within the sinus cavity can "push down" on the sinus floor and cause bone resorption. The result is an enlarged sinus (hyperneumatized sinus). A sinus lift may be necessary to "push" up the sinus floor.
- Periodontal Disease - With periodontitis, bacteria not only affects and causes gingival inflammation, but bacteria has begun to erode the bone structure and cause bone loss. If periodontal disease is not treated with the appropriate dental cleaning, it may lead to tooth loss and subsequent bone loss.
- Tumors - Abnormal growth can be either benign or cancerous. If either tumors are not controlled or removed it can cause bone destruction and loss.
- Developmental Defect - Some cases of birth defects can cause portions of the jaw bone to be missing or irregular in density and amount.
- Accidental Trauma - Unfortunate accidental circumstance in a dental emergency, these trauma cases may result in tooth loss. Accidents may include inadvertent heavy sports contact, playground mishaps, automobile accidents, and accidental slips and falls. With loss of tooth eventually follows loss of bone.
- Orthodontic Malposition and Misalignment - If a tooth does not have an opposing dentition, said tooth can super erupt (over erupt), causing bone loss.
- Dentures - A denture is a removeable prosthesis that replaces one or more missing teeth. The denture, complete or partial, can be anchored by a dental implant to help with retention. The denture area that is not anchored by a dental implant can result in alveolar bone loss as the tissue beneath said area is not stimulated.
- Dental Bridge - A dental bridge is a permanent prosthesis designed to replace a missing space by attaching a "floating" tooth between two or more adjacent front and back crowns. The portion of the bridge filling in the gap of the missing tooth that does not stimulate the jaw's alveolar bone can result in bone loss. Good oral hygiene via proper brushing and flossing is also needed to prevent bone loss around the attached crowns.
- Osteomyelitis - Rare case where bacteria has caused an infection of the jawbone and bone marrow. Result is bone inflammation and reduced blood flow, causing bone necrosis and loss.
SO WHY IS BONE GRAFT NECESSARY?The jaw bone's, also called alevolar bone, main purpose is to support and hold a tooth firmly in place. In order for a tooth to be stable and not be mobile, the area needs to have sufficient bone. Without adequate bone, the tooth can have periodontal issues and eventually lead to tooth loss.
With a dental implant, the bone serves the same structural support purpose. The jaw needs to have sufficient bone structure to support the implant firmly. In the case of a tooth extraction, it may be possible to place a dental implant same day immediately after the tooth is removed. Sometimes it may not be feasible to place an "immediate implant" due to a dental infection. In such situations a socket preservation graft may be necessary, as this graft fills up the void from the extracted tooth. The graft retains the bone volume while the adjacent alveolar ridge proliferates and fills the missing space with live bone. Typically the preservation graft may take between three to six months healing times before an implant can be placed.
If you have any questions on dental implants and bone grafts, be sure to consult your family dentist.
From your gentle family dentist in Bellevue,
Dr. Peter Chien