Jawbone loss is a common consequence of losing natural teeth. This occurs because the bone that once supported the tooth root no longer receives stimulation from chewing forces. The body interprets the bone as unnecessary and begins to break it down, leading to a reduction in the height and width of the jawbone. Despite this condition, obtaining dentures remains possible, though bone loss significantly alters the type of prosthetic device and the preparatory procedures required. The path forward shifts from simply replacing missing teeth to strategically utilizing or rebuilding the remaining jaw structure to ensure a stable, functional result.
How Bone Loss Affects Traditional Dentures
Traditional dentures rest directly on the gum tissue and the underlying jawbone ridge. When significant bone resorption occurs, this ridge flattens and shrinks, eliminating the natural contours that provide a mechanical lock for the denture base. Without this stable foundation, the denture becomes loose and prone to shifting, requiring frequent adjustments.
This instability reduces the wearer’s ability to chew effectively and impacts speech clarity. The movement of an ill-fitting denture creates friction and pressure spots on the gums, resulting in chronic irritation and painful sores. The pressure exerted by the denture during chewing can also accelerate underlying bone atrophy, creating a negative cycle of worsening fit. Studies indicate that the jawbone can shrink by as much as 25% in the first year following tooth extraction, and this process continues over time.
Reduced bone volume also affects facial aesthetics. As the underlying bone shrinks, the vertical dimension of the lower third of the face decreases, and facial soft tissues lose support. This can lead to a noticeable “sunken-in” appearance around the mouth and cheeks. These complications highlight why alternatives to conventional dentures are often recommended when substantial bone loss is present.
Diagnostic Assessment of Jawbone Volume
Assessing the amount and quality of the remaining jawbone is a key step in planning successful denture treatment. A dentist or prosthodontist begins with a clinical examination, often supplemented by panoramic X-rays. However, the standard for evaluating bone for prosthetic planning is the use of Cone Beam Computed Tomography (CBCT) scanning.
The CBCT scan provides a high-resolution, volumetric image of the jaw, allowing the clinician to take precise measurements of the residual bone structure. The scan measures the bone’s height, width, and density across various points of the arch. This detail is necessary to determine if there is sufficient bone to safely place dental implants and to plan the implant’s size and angle. The 3D visualization also allows the practitioner to map critical anatomical structures, such as nerve canals and sinus cavities, ensuring they are avoided during surgical procedures.
Advanced Denture Solutions Utilizing Existing Bone
When moderate bone loss occurs, advanced prosthetic solutions utilize the available bone mass rather than relying solely on the shrinking ridge for support. Implant-supported devices improve upon traditional dentures because the implants act as artificial tooth roots, providing mechanical stimulation to slow or halt further bone resorption. These solutions fall into two main categories: removable and fixed.
Implant-Retained Overdentures
Implant-retained overdentures are removable prosthetics that snap securely onto implants, typically between two and six per arch. The implants provide superior retention and stability compared to standard dentures, and the prosthetic can be removed by the patient for cleaning. This is often a more affordable solution.
Fixed Options (All-on-4)
The fixed option, commonly referred to as the All-on-4 technique, uses four strategically placed implants to support a permanently secured, full-arch bridge. This approach is effective in cases of moderate bone loss because the two posterior implants are placed at a precise angle to engage the denser bone found in the front of the jaw. This strategic angling often eliminates the need for extensive bone grafting, allowing patients to receive a stable, non-removable restoration that functions much like natural teeth.
Surgical Preparation for Optimal Denture Support
If bone loss is too severe to support implants, the foundation must first be rebuilt through bone grafting and ridge augmentation procedures. Ridge augmentation restores the lost height or width of the alveolar ridge, creating a better base for implants or a more stable conventional denture. This procedure involves lifting the gum tissue, placing the grafting material onto the deficient area, and covering it with a protective barrier membrane.
Several types of grafting materials are available, each serving as a scaffold for the body’s natural bone cells to regenerate:
- Autogenous grafts, taken from the patient’s own body, are considered the gold standard because they promote the fastest healing and bone formation.
- Allografts, which are derived from human donors.
- Xenografts, which are derived from animal sources.
- Alloplasts, which are synthetic, lab-made compounds.
The choice of material depends on the extent of the defect and the surgeon’s preference. The graft site is sutured closed, and a significant healing period is required before implants or final prosthetics can be placed. While initial recovery takes about a week, the bone graft can require up to a full year to integrate and mature, ensuring the new bone is strong enough to support chewing forces.