Today with a very high success rate of up to 99% in the anterior regions, implant becomes one of the major treatment armament in dentistry. The use of implant eliminated the need for the abutment teeth at the mesial and distal ends as in the conventional bridge, which may introduce more future problems in term of bone support and the pulpal health in the abutments. In many situation, preparation of the abutment leads to pulpal involvement. By undergone root canal treatment for the pulpal involvement, the abutment lose its defense mechanism. In the pontic area, alveolar ridge atrophy leads to problems as the resulting space between the ridge and the bottom of pontic causing food impaction, tissue ulceration, bleeding, and inflammation. Esthetically, the ridge atrophy buccolingually causing the pontic to cast a dark shadow on the gingival contour and the restoration being unable to integrate into the surrounding environment. Finally, the poor oral hygiene due to more difficulty cleaning in the abutments area leads to localized periodontally disease and ultimately tooth loss. Due to these reasons, more and more bridge restoration is converted to imlant restoration especially when one of the problem discussed above exist. Alveolar ridge expansion is used very frequently to augment the resorbed under the pontic in preparation for implant placement.
Another situation where alveolar ridge expansion is indicated is in the area of tooth loss for a long time. Alveolar ridge resorbs, compromises the bone width for proper implant placement.
Another situation for the anlveolar ridge expansion is when buccal bone plate was fracture during the extraction procedure of an anterior maxillary tooth and the site is anticipated for implant placement. The expansion will done at the implant surgery, using the osteotomes.
Finally, alveolar ridge expansion is also a common procedure in the patient who undergoes orthodontic treatment to regain the space for the congenital missing teeth. Before implant can be placed, the alveolar ridge needs to be expand simultaneously at the implant surgery appointment because the bone width usually is inadequate and also to achieve esthetic in the facial contour of the ridge. In these situation, implant placement may be delayed due to the severe deficiency in bone width in the implant site. Usually when the bone width is less than 5mm in the porous compact bone, implant surgery should be delayed.
In these situations explained above, implant placement and simultaneous ridge expansion with osteotome (if possible based on bone density) is definitely a treatment of choice.
What is the bone density and how does it affect the procedure of alveolar ridge expansion?
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.