Introduction:
The alveolar bone is the thick ridge of bone that surrounds and supports the roots of teeth. It forms the sockets (alveoli) that hold the teeth in place within the jawbone. Alveolar bone undergoes continuous remodeling throughout life in response to forces exerted by chewing and other factors. It is crucial for maintaining tooth stability and proper function of the teeth and surrounding structures. In cases of tooth loss or periodontal disease, the alveolar bone can be resorbed, leading to bone loss and potential complications for dental health.
What Are the Signs of Alveolar Bone Loss?
Signs of alveolar bone loss can include:
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Loose Teeth: As the bone supporting the teeth diminishes, teeth may become loose or shift position.
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Receding Gums: As bone loss progresses, gums may recede, exposing more of the tooth’s root.
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Changes in Teeth Alignment: Bone loss can affect the alignment of teeth, leading to changes in the bite pattern.
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Increased Sensitivity: Exposed tooth roots due to bone loss can lead to heightened sensitivity to hot, cold, or sweet foods and drinks.
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Difficulty Chewing: Reduced bone support can impact the stability and function of teeth, making chewing more difficult.
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Gum Inflammation: Bone loss is often associated with gum disease, leading to inflamed and bleeding gums.
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Visible Gaps Between Teeth: As teeth lose bone support, gaps or spaces may become apparent between them.
What Are the Complications of Bone Defects or Bone Loss?
Defects in the oral and maxillofacial region may be due to various causes. However, the reconstruction of alveolar bone defects is complex because the alveolar bone tends to be resorbed immediately after losing a natural tooth. Though many systemic and immunologic conditions and syndromes are implicated with alveolar bone loss, periodontal disease is the most generalized and common cause of alveolar bone loss. In this condition, the oral immune defense is primarily breached, and the host immune response is evoked due to the release of inflammatory mediators. Periodontitis or periodontal disease is also simultaneously linked with defective neutrophil and immune cell mechanisms, resulting in alveolar bone loss. In patients suffering from long-span edentulism (due to extracted or exfoliated teeth), the bone loses its volume and tone and gets reabsorbed within a few months, causing jaw issues. In older individuals, loss of teeth in any segment or entirely will result in loss of facial muscle tone and cause sagging.
According to research and recent evidence, though various multifactorial causes may exist to cause bone loss around teeth and create these moderate to large-sized alveolar defects in the jaw, the prevention and management of periodontitis is a mainline gold standard conservative treatment modality to avoid the clinical challenges faced for prosthetic rehabilitation in long term or long span edentulism or severe alveolar bone defects.
In medication-induced damage, tissue damage is considered one of the factors causing defective alveolar bone structure. As this alveolar bone support is mainly needed for a crown, bridge, or implant-supported prosthetic rehabilitation, the dentist's maintenance is pivotal for any prosthesis's long-term survival. For dental implants, an insufficient amount of bone volume and bone density not only compromises the support needed for implant osseointegration but also results in an unstable fixture of the implant where its primary stability may be compromised, leading to failure of the functional prosthesis. Hence, the quantity, quality, and density of the alveolar jaw bone are crucial factors that are affected either due to local trauma or systemic disease and chronic conditions.
What Are the Local and Systemic Causes of Alveolar Bone Loss?
The below-enlisted factors, according to dental literature and research, are implicated as causative factors for causing alveolar bone loss:
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Periodontitis.
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Long-standing tooth loss.
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Infection due to dental caries.
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Trauma.
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Oral infections.
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Drug-induced medications may cause osteonecrosis of the jaw (ONJ); for example - Bisphosphonate drug therapies.
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Iatrogenic errors like misuse of specific irritating agents (endodontic devitalizing agents).
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Systemic diseases include diabetes mellitus, chronic hypertension, hypophosphatasia, leukemias, and scleroderma.
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Down’s syndrome, Chediak Higashi syndrome, and Papillon Lefevre syndrome may also cause alveolar bone loss.
The dentist should constantly evaluate factors like patient age, systemic conditions, oral hygiene, and other local elements before the prosthetic rehabilitation (crown, bridge, or dental implant). In addition, the dentist should carefully consider the use of specific endodontic devitalizing agents, as recent dental research implicates that specific symptoms like persistent pain, tooth loss, or oroantral openings may occur at the tooth extraction site.
How Is Alveolar Bone Defect Reconstructed?
In implant dentistry, bone graft augmentation and guided tissue regeneration are key modalities now employed for long-term prosthetic success. The same technique can be used for filling alveolar bone defects. Multiple biomaterials or graft materials exist for these alveolar defects and include:
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Autogenous.
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Allogenous.
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Xenografts.
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Alloplastic graft materials.
Autogenous Bone Graft - It is considered the gold standard bone graft because, either by extraoral or intraoral donor sites, the material can be chosen from the patient for graft reconstruction to fill the alveolar defects by character, shape, and size. The extra-oral sites used for bone graft are usually the external iliac crest, the calvarium, the tibia, etc. In contrast, the intraoral donor sites involved are the mandibular ramus, the chin, the zygomatic buttress, or the tuberosity region. The AIC or the anterior iliac crest as a donor site has come to be a popular donor site option of all the extra-oral sites, given that it lies very close to the subcutaneous layers of the skin with a natural curvature that is deemed suitable by prosthodontists for replicating the curvature of the alveolar bone.
Some evidence indicates better results with cancellous bone grafts over cortical grafts. This is because the cortical bone can induce bone regeneration by osteoconduction. In contrast, cancellous grafts can induce osteogenesis (bone formation) by bone cell proliferation because of their rich osteogenic cell contents. The dental surgeon should also consider the possibility of drug interference and interactions in patients suffering from systemic diseases while reconstructing the alveolar defects of the jaw. Hence, a multidisciplinary approach may be required to consult the health care provider or physician about the impact of certain medications and long-term clinical systemic health issues. The dental operator should take care of the bone graft material in autogenous grafts during reconstruction or isolation to avoid hematomas, edema, pain, or vascular rupture.
Conclusion:
Alveolar bone loss is a crucial impediment to prosthetic rehabilitation in these patients. Hence, thorough evaluation and assessment by the dental surgeon, a multidisciplinary approach to systemic disease, and the use of reconstructive graft modalities along with guided bone regeneration can help achieve long-term prosthetic success.
