Bone density have been classified by Carl Misch as followed (from most dense to least dense):
- Dense compact
- Porous compact
- Coarse trabecular
- Fine trabecular
The dense compact bone is very dense and found in the resorb anterior mandible. A threaded implant will provide immediate fixation and initial stabilization. This bone type represents the greatest percentage of bone at the implant interface (80%). On the opposite end of the spectrum, the fine trabecular bone has very light density and no cortical crestal bone. It can be found in the posterior maxilla of the long term edentulous patient. It is very porous and thus bone height and width is crucial in term of implant initial stability during placement.
There are two ways to perform alveolar ridge augmentation. When the available bone width is five millimeter or less, the ridge can be expanded or augmented using the conventional guided bone regeneration technique. For more information regarding the technique of guided bone regeneration, please select Guided Bone Regeneration under the services menu. On the adjacent black column is an example of a case using orthodontic and implant therapy to restore areas of congenitally missing teeth. Patient requested orthodontic treatment to treat her midline shift due to the congenitally missing maxillary central incisors. After a thorough examination, Dr. Bui decide to use rapid palatal expansion (RPE) appliance and orthodontic for space management in preparation for implant placement to replace the missing upper left central incisor. After the insertion of the RPE appliance, patient went to Carolina for three months for her vacation. The end result is the overexpansion and the posterior teeth were occluded in complete lingual cross bite. After orthodontic therapy has been instituted to correct the lingual cross bite and prepare the implant space, maxillary alveolar ridge expansion using GBR is used to regain the bone width for future implant placement. For full presentation of this case done in Flash, please browse our porfolio section, under “RPE, Orthodontics, and Implant to Treat Congenital Missing Teeth
The second and more preferred way to expand the alvolar ridge is to use the surgical tools called osteotomes. Osteotomes is set of cynlindrical stainless steel cylinder (similar to a smaller version of ring sizer) of various size. They are used in periodontal surgery to laterally compact the bone and expand the ridge and the opening for implant placement. The denser the bone the harder for the expansion to be performed with osteotomes. Also the bone width must be at least four millimeters (preferrably five millimeters) or more for the use of osteotomes. Below is the case at Cosmetic Dentist of Katy of which osteotomes is used to expand the alveolar ridge that undergone resorption following an extraction. A size 4mm diameter implant was placed simultaneously. I believe osteotome expansion should always be considered especially when the implant is placed in the maxilla due to the fact that the procedure will enhance the bone-to-implant surface area for osseointegration by increased the bone density surrounding the placed implant.