Dentures are prosthetic devices designed to replace missing teeth and surrounding gum tissue. While many people think of dentures as a full set for both the upper and lower jaws, treatment is often customized. A single arch denture focuses the restorative effort on just one curved row of teeth. This targeted approach addresses tooth loss in the affected jaw while preserving existing healthy structures.
Defining the Single Arch Denture
A single arch denture (SAD) is a dental appliance that replaces teeth in either the maxillary arch (upper jaw) or the mandibular arch (lower jaw). It is distinct from a full set of dentures, which replaces all teeth in both jaws. The single arch prosthetic is supported by the remaining gum tissue and bone of the jaw it rests upon.
The components typically include a gum-colored base, usually made from acrylic resin designed to mimic the natural appearance of the gums. Embedded within this base are prosthetic teeth, selected to match the color, size, and shape of the patient’s existing natural teeth. SADs are categorized as either complete, replacing all teeth in the arch, or partial, replacing only a few missing teeth.
When Only One Arch Is Needed
A single arch denture is prescribed when tooth loss is confined to one jaw, and the opposing arch contains sufficient healthy, functional natural teeth. This scenario requires careful evaluation of the remaining natural dentition to ensure it is periodontally sound and has a stable biting relationship. Preservation of healthy natural teeth is prioritized, as they withstand significantly greater chewing forces than a denture.
The decision to place a SAD is complex because the natural teeth in the opposing jaw can exert forces nearly eight times greater than those generated by a full set of dentures. These powerful forces increase the risk of accelerated bone loss (ridge resorption) and frequent fracture of the denture base. Therefore, the dental professional must meticulously plan the alignment of the new prosthetic teeth to achieve a harmonious bite, known as occlusion, with the existing natural teeth.
Design and Construction Process
The fabrication of a single arch denture begins with taking accurate preliminary and final impressions of the edentulous or partially edentulous arch. An impression of the opposing arch, which contains the natural teeth, is also taken. These molds ensure the final appliance will fit and function correctly against the existing dentition. A dental laboratory uses these molds to create working casts, which are mounted onto an articulator to replicate the patient’s jaw movements.
Establishing the Bite
A crucial step involves establishing the occlusal plane, the imaginary surface where the upper and lower teeth meet during biting. Because the opposing arch may have shifted or tilted teeth, the dentist often must modify the natural teeth surfaces. This ensures a balanced contact with the new prosthetic teeth.
Partial Denture Framework
For a single arch partial denture, a metal framework, often made of chrome cobalt, is designed to provide support, stability, and retention. This framework clasps onto the remaining natural teeth. The framework is then covered with the acrylic base and prosthetic teeth.
Final Fitting
The process includes a wax try-in appointment, where the patient tests the arrangement of the prosthetic teeth for aesthetics and comfort before final processing. Once approved, the wax is replaced with durable acrylic resin under heat and pressure to form the definitive denture. The appliance is polished and returned for the final fitting. Minor adjustments are made during this fitting to ensure a comfortable and stable fit against the gums and a proper bite with the opposing arch.
Daily Care and Maintenance
Proper daily care is necessary to maintain the longevity of the single arch denture and the health of the surrounding oral tissues. The denture must be removed and cleaned at least once a day using a soft-bristled brush and a non-abrasive cleaner. Regular toothpaste should be avoided because its abrasive ingredients can scratch the acrylic surface, creating spaces where bacteria can accumulate.
When the denture is not being worn, it must be stored in water or a mild denture-soaking solution. Allowing the acrylic to dry out can cause the material to warp and change shape. It is recommended to remove the appliance overnight to allow gum tissues to relax and recover from daily pressure.
In addition to cleaning the denture, the patient must brush any remaining natural teeth and gently clean the tongue, cheeks, and gum ridge. Regular check-ups are important to monitor the fit of the denture, assess the health of the opposing natural teeth, and ensure the appliance is not causing undue stress on the jawbone.