Advanced Bone Grafting – Widening The Narrow Alveolar Ridge
The most common challenge in placing dental implants is inadequate bone width at the implant site. When teeth are lost so too is bone through disuse atrophy, infection, and/or trauma. If a critical amount of bone is lost then the jaw bone needs to be built up or grafted to allow implant placement. There are many approaches used to widen the narrow alveolar ridge or jaw bone. Autogenous bone is obtained by harvesting bone from the patients jaw and placing it at the implant site. Onlay grafts (which are composed of solid blocks of autogenous bone) do not compress and are one way of accomplishing ridge widening. However, donor site morbidity and the need to shape the bone make onlay grafts more time consuming and increase patient recovery time. When using a particulate graft (bone obtained from a tissue bank with the consistency of sea salt) compression and loss of volume are inevitable. Using a particulate or allograft avoids the need to harvest bone from the patient’s own jaw and reduces postoperative discomfort. The challenge in using this type of graft to increase ridge width is maintaining the shape of the grafted area while the graft is healing. Soft tissue contracture applies pressure to the particulate graft, compacting and flattening it, reducing the final width of the grafted ridge. One way to support the soft tissue and prevent the graft from being compressed is to use bone screws which act like tent poles to support the mucoperiosteum or gum tissue. When the ridge is less than 4 mm wide, I often use the Tent Pole technique. Typically, the graft is placed along with the tenting screws and if adequate bone is present the dental implants may be placed at the same time. After 4 to 6 months of healing the tenting screws are removed easily with a small incision over the head of the screw. The dental implants are then placed if this has not already been done at the time of grafting. The case below is typical and should result in a ridge that was widened from 2 mm to 6 mm. The tenting screws shown in fig.1, particulate bone graft placed over the screws fig. 2, and a collagen membrane placed over graft to aid in supporting the tissue and protect the graft from soft tissue ingrowth fig. 3.