The mandibular alveolar ridge is a bony structure in the lower jaw, or mandible, that houses the sockets for the lower teeth. It provides foundational support, anchoring the roots of the teeth within the jawbone.
Understanding the Mandibular Alveolar Ridge
The mandibular alveolar ridge is a distinct bony arch in the lower jaw, designed to surround and support tooth roots. It contains individual tooth sockets, or alveoli, tailored for each tooth. The bone lining these sockets, called the alveolar bone proper, connects to the tooth root via the periodontal ligament.
This ridge provides stable anchorage for teeth, allowing them to withstand chewing and biting forces. Mechanical stimulation from these forces is relayed through the periodontal ligament to the alveolar bone, which has an outer layer of compact bone and a spongy inner core. This load-bearing activity helps maintain the bone’s density and form.
How the Ridge Changes After Tooth Loss
After a tooth is lost or extracted, the alveolar bone that once supported it undergoes a process called resorption, which is essentially bone shrinkage or atrophy. This occurs because the natural stimulation from chewing forces, transmitted through the tooth root, is no longer present. Without this mechanical load, the body no longer perceives a need to maintain the bone in that area.
The most significant changes occur rapidly, with studies indicating that much of the bone loss happens within the first six months to a year following extraction. Horizontal bone loss can range from 29% to 63%, while vertical bone loss may be between 11% and 22% within six months. This reduction in bone volume means the ridge becomes narrower and flatter, losing both height and width. Over time, this can lead to visible changes in facial appearance, such as a “sunken” or aged look, as the jawbone provides underlying support for the lower face.
Impact on Dental Prosthetics
An atrophied mandibular alveolar ridge presents considerable challenges for common dental prosthetics. For traditional dentures, which rely on resting directly on the gums and underlying bone, a diminished ridge leads to poor fit and instability. This can result in the denture slipping, causing discomfort, soreness, and difficulty with speaking and eating. Patients may experience a reduction in chewing efficiency, sometimes as low as 10% compared to natural teeth.
Insufficient bone volume also significantly complicates the placement of dental implants. Implants require adequate bone density and height for stable integration, and a resorbed ridge often lacks these conditions. This often necessitates additional surgical procedures, such as bone grafting, before implants can be successfully placed. Without sufficient bone, the longevity and functionality of dental implants can be compromised.
Strategies for Ridge Preservation and Restoration
Several techniques are employed to manage or reverse the changes to the mandibular alveolar ridge after tooth loss. Socket preservation, also known as ridge preservation or augmentation, is a procedure performed immediately after tooth extraction. This involves placing bone graft material into the empty tooth socket to help maintain the existing bone volume and prevent its collapse. This helps to preserve the natural contour of the jawbone and surrounding gum tissue.
For areas where significant bone resorption has already occurred, ridge augmentation or bone grafting procedures are used to rebuild lost bone height and width. These procedures involve adding bone graft material, which can be sourced from the patient’s own body, a donor, or synthetic materials, to regenerate the jawbone. The goal is to create sufficient bone volume, often to prepare the site for dental implant placement or to improve the retention and stability of traditional dentures. Dental professionals assess individual needs to recommend the most appropriate strategy.