Introduction:
Over the last decade, with the immense advent and revolutionary bone advancement techniques and protocols in implant dentistry and surgical incompetence reconstructive surgery, different materials or bone augmentation materials have been used to facilitate dental implant placement or after tumor resection. Read on and learn about it.
What Are the Challenges of Resorbed Maxilla and Mandible for Bone Grafts?
Though dental implants can be considered a gold standard prosthetic replacement for missing teeth, there are certain criteria by which dental patients can be deemed suitable cases for implants. A challenging task for a dental implant specialist (implantologist) is to place implants in the region with inadequate alveolar bone. Rehabilitation of dental patients with severely resorbed or fewer amounts of alveolar jaw bone, be it in the maxillary or mandibular regions (i.e., in the upper or the lower jaw), can be a challenging task for the dental implant specialist. Some implant specialists see this as a clear contraindication - i, e when there is a situation like there is very little underlying jaw or alveolar bone, medically termed severely resorbed maxillary and mandibular alveolar bone, it becomes difficult to place dental implants as primary stability is compromised. It is a well-known fact in dental literature that the primary stability of dental implants plays a major role in determining the long-term success and survival rates of dental implants. Therefore, severely resorbed maxillary or mandibular bone can be seen as a clear contraindication for dental implantation.
What Materials Are Used for Jaw Bone Grafts?
A general lack of or physiologic recession of bone in geriatric (elderly) patients as well as in patients from different age groups ( above the age of 18) can be treated by oral and maxillofacial surgeons or implant dentists using autologous allogenic, xenogenic, or synthetic material grafts.
These four different types of graft materials or techniques based on these materials are deemed the current bone augmentation modalities for promoting bone growth or the process of osteogenesis in the resorbed maxillary or mandibular (upper or lower jaw region). Currently, according to dental researchers and implant specialists, autologous bone grafts are considered to be the most effective and gold-standard procedure before performing surgery for dental implants or dental implantation. Autologous bone grafts (bone taken from the patient's own body) obtained from the donor sites of the patient and implanted then into the recipient bed of the patient, such as from different anatomic locations of the patient's body have been holding the potency to promote the process of osteogenesis or bone formation in the resorbed area of the upper or lower jaw.
This is attributed mainly to the presence of mesenchymal stem cells in the autologous bone graft materials that can be responsible for the possible success of bone augmentation.
It is to be noted that several modern-day augmentation methods or modalities using other graft materials like xenografts (grafts taken from a different species), allografts (grafts taken from a donor of the same species), alloplastic materials (synthetic graft materials) that are combined with autologous bone (bone taken from the patient's own body), or even the possible use of stem cells (undifferentiated cells that can develop into specialized cells.) that can be combined with the xenograft matrix (scaffold or framework derived from a different species) or alloplastic graft matrix, are some of the augmentation techniques for maxillary and mandibular (upper and lower jaw bone), for which considerable success rates have been reported before dental implantation.
What Are the Possible Sites for Autologous Grafts?
For large augmentation of the maxillary or mandibular bone, such as in the cases of reconstructive surgeries of the head and neck or case of post-operative treatment following tumor resection surgeries as well, autologous bone grafts can be quite ideal, considering them as a gold standard benchmark for such extensive grafts. This is because, in terms of both shape and bone quantity, autologous bone grafts can be harvested effectively from the patient's donor site and the anatomical sites listed below. These sites are the usual areas from which bone can be harvested to augment the extensively resected or resorbed bony areas of the maxillary and mandibular regions:
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Anterior or posterior iliac crest (front or back parts of the pelvic bone).
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Tibia (shinbone, a large bone in the lower leg).
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Coronoid process (bony prominence on the jawbone).
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Maxillary tuberosity (rounded elevation at the back of the upper jaw).
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Retromolar area (behind the last molar in the lower jaw).
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Mandibular symphyseal area (midline of the lower jaw).
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Ribs.
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Calvarium (skullcap or the upper part of the skull).
What Are the Common Complications Encountered?
However, implant dentists or maxillofacial surgeons may still find it difficult in terms to perform bone augmentation at the area of resection of resorption because, in general, common surgical complications such as swelling, inflammation, mobility of bone, or infections of the bone grafts themselves or sensory deficits, wound dehiscences can commonly occur. These common complications that can occur postoperatively following a bone augmentation can cause infection and failure of the bone graft materials placed. This is the reason why immunocompromised patients have poor or rather contraindicated criteria for dental implant placement, because they may often face functional as well as esthetic challenges when the bone graft fails. Accelerated resorption of the bone graft can lead to complete failure in individuals with certain systemic conditions, some genetic syndromes, and in individuals who are immunocompromised or in high-risk geriatric group patients.
What Conditions Can Lead to Graft Failure?
Other factors that cause bone graft failure are common systemic conditions such as uncontrolled type 2 diabetes or diabetes mellitus, patients with a history of chemotherapy and radiotherapy post-cancer surgeries, individuals with a previous history of uncontrolled or untreated periodontal or gingival diseases or infections, individuals with scar tissues are all possible cases that should be contraindicated for bone graft placement in the jaw. The presence of such uncontrolled underlying systemic factors can lead to necrotic tissues, fibrosis, scarring, or deformities occurring in the tissues instead of proper soft tissue healing over the bone graft, causing graft failure in the jaw.
Conclusion:
Hence, in the cases of healthy implant subjects and in post-operative reconstruction surgeries, the implant dentist or the maxillofacial surgeon takes a lot of preventive steps apart from giving the dental patients strict oral hygiene practices and control measures to prevent any possible infection of the jaw bone grafts. Interdisciplinary collaboration with the physician can also be beneficial in preventing systemic infections or causing bone graft failures of the jaw in geriatric patients.
