Alveolar bone loss occurs when the bone surrounding and supporting the roots of teeth recedes, usually due to chronic inflammation. This structural loss compromises tooth stability, potentially leading to mobility and eventual tooth loss. While the body has a natural capacity for bone remodeling, regeneration of lost bone around teeth is highly limited. Modern dentistry provides surgical and non-surgical treatments that can halt this progression and promote the regrowth of supporting bone tissue.
Understanding Alveolar Bone Loss
The most common cause of bone recession is chronic periodontitis, an advanced stage of gum disease initiated by a bacterial infection. Bacteria within dental plaque trigger a host immune response, leading to sustained inflammation in the gum tissues. This inflammation is the primary driver of damage to the bone structure.
The host response involves the release of inflammatory signaling molecules, such as cytokines, which disrupt the normal balance of bone remodeling. Normally, bone is continually broken down by osteoclasts and rebuilt by osteoblasts. In periodontitis, the inflammatory environment over-activates the osteoclasts, causing bone resorption to dramatically exceed bone formation, leading to net bone destruction around the tooth roots.
While periodontitis is the central mechanism in most cases, other contributing factors include physical trauma, excessive biting forces, and systemic conditions like uncontrolled diabetes. These factors exacerbate the inflammatory response to the bacteria.
Why Natural Regrowth Is Limited
The biological barrier to natural bone regrowth lies in the different healing rates of the tissues surrounding the tooth root. Healing involves a competition for space among four tissue types: gum tissue (epithelium), connective tissue, bone, and the periodontal ligament. Epithelial cells are highly proliferative and migrate rapidly down the root surface.
This fast-growing gum tissue quickly fills the space where the bone once was, forming a long junctional epithelium instead of new bone or ligament attachment. Bone-forming cells (osteoblasts) and periodontal ligament cells grow much more slowly. By the time these slower-growing cells arrive at the defect site, the epithelial tissue has already occupied the available space, preventing bone regeneration.
The oral environment favors the rapid closure of the wound by soft tissue, which outcompetes the slower osteogenic (bone-forming) cells. This cellular competition prevents the body from spontaneously regenerating significant amounts of lost alveolar bone, making professional intervention necessary for structural repair.
Surgical Methods for Bone Regeneration
When bone loss is significant, surgical approaches create a protected environment that favors new bone formation. These procedures rely on the principle of selective cell exclusion, blocking the rapid migration of epithelial cells while providing a scaffold and biological signals for bone growth. Common techniques include Guided Tissue Regeneration (GTR), Guided Bone Regeneration (GBR), and various bone grafting procedures.
GTR and GBR utilize specialized barrier membranes placed over the bone defect. This physical barrier creates a secluded space, preventing faster-growing soft tissues from entering and allowing the slower bone and periodontal ligament cells to populate the area and regenerate the lost structure. GBR is often used to augment bone volume, especially in preparation for dental implants, while GTR focuses on regenerating the entire periodontal attachment, including new cementum and periodontal ligament.
Bone Grafting Materials
Bone grafting is frequently combined with GBR and GTR to provide a supportive matrix. Graft materials function as a scaffold, providing an osteoconductive framework that directs the patient’s own bone-forming cells to deposit new bone within the defect. Success relies on a stable environment, sufficient blood supply, and tension-free closure of the gum tissue over the membrane and graft material.
Graft materials vary:
Autografts use bone harvested from the patient’s own body.
Allografts use donor bone.
Xenografts utilize material from a non-human species, such as bovine bone.
Stopping the Progression of Bone Loss
Before considering surgical reconstruction, eliminating the bacterial cause of inflammation is necessary. Non-surgical periodontal therapy, primarily scaling and root planing (SRP), is the standard for controlling the disease and preventing further bone destruction. Scaling involves a deep cleaning below the gumline to remove bacterial plaque and hard calculus deposits from the root surfaces.
Root planing then smooths the root surfaces to remove bacterial toxins and make it difficult for new plaque to adhere, facilitating gum tissue reattachment. For deep or difficult-to-reach pockets, locally administered antibiotics can be placed following SRP to target persistent bacteria. This therapy reduces inflammation, stabilizing the existing bone level by reducing the over-activation of bone-resorbing osteoclasts.
Long-term success depends on meticulous oral hygiene and regular professional maintenance appointments, often referred to as periodontal maintenance. Lifestyle modifications, such as smoking cessation and controlling systemic conditions like diabetes, are important, as these factors accelerate bone loss. Controlling the infection and inflammation halts the progression of the disease, which is a prerequisite for any attempt at bone regeneration.