Everything related to implant dentistry involves a strong understanding of human craniofacial anatomy. To treatment plan, a clinician must have knowledge of anatomical concerns such as the sinuses and the locations of the mental foramens, the incisal foramen, the mandibular nerve....
November’s Implants Today topic is bone grafting for implant placement. If you are a dentist focusing on dental implants as a treatment modality, then bone anatomy, bone physiology, and bone grafting should be understood on every level. Every aspect of implant dental treatment—from treatment planning and surgery to prosthetics—is dependent upon the clinician having adequate knowledge about bone science. Even a medical history review is related to understanding many things about bone science. An example of this is the relationship between the osteoporosis drugs (bisphosphonates) and the risks of osteonecrosis. Understanding the science behind why there is a risk with respect to how bisphosphonates work, allows for an optimal medical history review and improved treatment planning with the patient. This is just one example of many that justify the importance of a good understanding of bone science on the part of the clinician who places implants.
Understanding Bone Anatomy and Physiology
It is important for the clinician to have a strong of understanding bone anatomy and physiology. Everything related to implant dentistry involves a strong understanding of human craniofacial anatomy. To treatment plan, a clinician must have knowledge of anatomical concerns such as the sinuses and the locations of the mental foramens, the incisal foramen, the mandibular nerve, the infraorbital foramens, and much more. As I reference in many of these editorials throughout the year, a CBCT scan is imperative for the true understanding of anatomical relationships and pathology. The patient’s anatomy dictates both bone grafting and implant placement surgery. Understanding bone physiology is also important. When placing a bone graft material into an extraction site, or to graft the lateral wall of a ridge, the clinician should understand the physiological process that is happening at the site. Through understanding the actual process, the clinician can make the right surgical and grafting material choices. When a clinician chooses a graft material, that choice should be based on the size of the defect. The larger a defect is, the more osteoinductive properties a graft should have. Through understanding that defects with less walls of bone have less vascularity, the choice to use autogenous or an alloplastic bone would be made. This shows how knowledge of both bone anatomy and bone physiology is important and how they both interrelate.
Grafting Quadrant Dental Regions
Not only is gross anatomy important, but understanding the soft- and hard-tissue anatomy of different regions of the mouth is as well. An example is the anterior maxillary region versus the posterior mandibular region. The anterior maxilla is the most demanding area to graft in the mouth. If there is 2 mm of papilla loss in a patient with a high smile-line, it could affect the entire case. That 2 mm of papilla height loss can be associated with extraction technique, implant spacing, soft-tissue concerns, and more. Successful bone grafting is also related to knowledge of prosthetics. In the anterior region, ovate pontics at the time of grafting can create improved hygiene and aesthetics.
The posterior regions of the mouth create challenges other than aesthetic concerns. In the maxillary posterior region, the sinus is the main concern and how to manage it when grafting. Both lateral wall sinus grafts and osteotome lifts are common ways to graft for implant placement. These could occur during implant placement or may be staged before, depending on the case. In the mandibular posterior regions, the mandibular nerve is the dictating factor. In general, both the maxillary and mandibular regions are anatomically wide due to the ridge size. The width of the ridges affects the choice of graft materials and membranes that might be needed. As with all bone grafting, the blood supply is an important consideration.
Grafting in Relation to Full-Arch Treatment
When a full arch is being treated for tooth replacement, the considerations are different than with quadrant grafting and implant placement. The prosthetic choice for the full-arch treatment plan dictates the grafting protocol. If the treatment plan is for a screw-retained prosthesis that has pink gingiva (Misch fixed prosthesis 2 [FP2] and FP3) then, more than likely, the clinician will be reducing the height of bone and grafting in any extraction site defects. This is because adequate prosthetic height is needed and in the maxilla the high smile-line should hide the gingival prosthetic junction. When the prosthesis doesn’t require a pink gingival area (Misch FP1), then bone is not taken away but instead grafted to be maintained or increased. Different prosthetic choices dictating the grafting treatment plan.
This month, Implants Today advisory board member Dr. Craig Misch presents an outstanding article that shows how advanced the science of bone grafting has become. Craig is both an oral surgeon and a prosthodontist, and as a dual specialist, his article brings out many key concepts that are involved with bone grafting and implant dentistry. The tissue engineering advancements that he presents, tied in with advantages of an autogenous bone block, show a true blending of concepts. Between what has been presented above, and the excellent content of Craig’s comprehensive article, the reader can begin to grasp how successful interdisciplinary bone grafting is.
Also this month, Dr. Ahmad Soolari and Mr. Amin Soolari exemplify the principles of the need to graft bone to support implant placement. This article also shows the clinical choices of grafting materials, membranes, and the timing of an implant case.
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