Dentures, whether full or partial, are designed to rest on the soft tissues of the mouth, but the underlying bone and gums change over time. This continuous process, known as resorption, involves the gradual shrinking of the jawbone after tooth loss. As the bone and gum contours diminish, the denture’s fit becomes progressively looser, leading to instability, discomfort, and difficulty with speaking or eating. To restore the secure, comfortable fit and function of the prosthetic device, dental professionals commonly use two distinct procedures: relining and rebasing. Both techniques improve the contact between the denture and the oral tissues, but they differ significantly in their scope, method, and the severity of the issue they correct.
Understanding Denture Relining
Relining is a procedure focused specifically on adjusting the tissue-bearing surface of the denture to match the current contours of the wearer’s gums. This process involves adding new acrylic material only to the inside of the denture base, the part that directly rests against the soft tissues. The goal is to fill the space created by bone resorption and restore the intimate fit that provides proper suction and stability. Relining does not alter the vertical dimension or the visible outer appearance of the denture base.
The procedure is typically categorized into two types: hard and soft relines. A hard reline uses a durable, long-lasting acrylic resin, similar to the original denture base material, and often requires laboratory processing for a bubble-free, highly polished surface. This option offers a more permanent solution for improving stability and is often needed every two years. A soft reline, in contrast, uses a more pliable, cushion-like material, such as a silicone-based polymer, applied to the tissue surface. This softer material is often used temporarily to aid in the healing of irritated gums or for patients with sensitive residual ridges that require shock absorption.
While a hard reline may sometimes be performed chairside, the laboratory-processed method generally yields a smoother, denser material that lasts longer. The soft reline material, while providing immediate comfort, is more porous and requires more frequent replacement, typically every 12 to 18 months. In either case, the reline procedure begins with an impression taken directly inside the existing denture, which serves as the mold for the new lining material. This added material ensures the denture adapts precisely to the current shape of the mouth without changing the position of the artificial teeth.
Defining Denture Rebasing
Denture rebasing is a far more comprehensive and structural form of repair than relining, involving the complete replacement of the pink acrylic base material. The existing artificial teeth, provided they are in good condition and correctly positioned, are carefully preserved and reset into a brand-new foundation. This procedure is chosen when the entire acrylic base is structurally compromised, such as being severely fractured, weakened, discolored, or porous due to prolonged use. Rebasing effectively creates a like-new denture while retaining the patient’s established bite relationship and aesthetic.
The process is exclusively a laboratory procedure, meaning the wearer must be without their dentures while the work is completed, which usually takes several days. The dental technician takes an impression using the original denture and then uses a specialized device to maintain the exact position of the artificial teeth. The entire old pink base is removed, and a new, fresh acrylic base is processed around the existing teeth. This replacement not only improves the fit against the soft tissues but also restores the strength and hygiene of the entire prosthetic device.
Rebasing is often recommended when converting a temporary or immediate denture into a final, permanent prosthesis, or when a poor fit is accompanied by a deteriorated or compromised base structure. The procedure ensures a renewed lifespan for the denture, often extending its usability by several years.
Key Distinctions in Application and Outcome
Relining is primarily a maintenance procedure used for minor to moderate fit issues caused by normal gum shrinkage, where the acrylic base remains structurally sound. The added material simply resurfaces the interior for better retention.
Rebasing, conversely, is a foundational replacement, necessary when the denture base itself is structurally deficient, cracked, brittle, or severely discolored. It is a more extensive undertaking, as the entire pink acrylic is exchanged for a new one.
Consequently, relining is generally faster, sometimes completed in a single office visit, and less costly than rebasing. Rebasing requires a dental laboratory and is more expensive, but it yields a complete renewal of the denture’s foundation, offering a cleaner, stronger, and more durable result.