A root cavity can be filled, but its location and underlying tissue require distinct materials and processes compared to a typical cavity found on the chewing surface. Root surface decay occurs when gum tissue recedes, exposing the tooth’s root. The root surface is covered by cementum, a thin, softer material, unlike the hard enamel protecting the crown. Because this area is closer to the gumline and has less protective covering, decay progresses quickly and requires specialized dental attention.
Understanding Root Surface Decay
Root surface decay begins when receding gums expose the cementum layer to oral bacteria and acids. Gum recession, often caused by age, aggressive brushing, or periodontal disease, is the primary factor allowing this decay to start. Since cementum is significantly less mineralized and more soluble than enamel, decay can develop and spread approximately two to two-and-a-half times faster on the root surface than on the crown.
Several factors increase the risk of developing a root cavity. High-risk individuals include older adults, people with dry mouth (xerostomia) due to medications or medical conditions, and those with poor plaque control near the gumline. Reduced saliva flow means less natural acid neutralization, making exposed root surfaces highly vulnerable to demineralization. A diet high in fermentable carbohydrates and acidic foods also contributes significantly to the risk of this rapid decay.
Determining the Appropriate Treatment
The decision to fill a root cavity depends on how deep the decay has penetrated the tooth structure. For minor to moderate decay limited to the outer layers of the root, a simple filling is often sufficient. The goal is to remove the decayed tissue and restore the tooth’s integrity to prevent further bacterial invasion.
A more extensive procedure, such as a root canal, becomes necessary if the decay has progressed deep enough to infect the dental pulp—the soft tissue containing nerves and blood vessels. Severe, persistent pain or swelling indicates the infection has reached this inner chamber. If structural loss is too extensive, making the tooth unrestorable, extraction may be the only viable option to prevent infection spread. The dentist evaluates the severity and location of the decay, often using X-rays, to determine the most effective treatment plan.
Materials and Techniques Used for Root Fillings
Filling a root cavity presents unique technical challenges due to its location at the gumline and the softer root structure. The constant presence of moisture and difficulty isolating the area make traditional composite resins, which require a completely dry field for bonding, less suitable. Instead, dentists prefer materials specifically designed for these non-load-bearing areas.
Glass Ionomer Cements (GICs) and Resin-Modified Glass Ionomer Cements (RMGICs) are frequently chosen for root surface restorations. These materials chemically bond to the tooth structure, which is beneficial in the moist environment near the gum. GICs slowly release fluoride over time, helping remineralize the surrounding structure and providing defense against recurrent decay. While GICs are less durable than composite for chewing surfaces, their adhesive and fluoride-releasing properties make them effective for the susceptible root surface. The technique involves carefully preparing the shallow lesion, often with minimal drilling, and applying the restorative material directly.
Preventing Future Root Surface Cavities
Preventing recurrent root surface decay requires modifying oral hygiene habits and managing underlying risk factors. Because the exposed root is vulnerable, using a soft-bristled toothbrush and a gentle brushing technique is important to avoid further gum recession. Brushing twice daily with fluoridated toothpaste helps strengthen the tooth structure against acid erosion.
For high-risk individuals, professional fluoride treatments, prescription-strength toothpaste, or fluoride mouth rinses are effective in reducing new decay. Managing dry mouth, perhaps through saliva substitutes or consulting a physician about medication side effects, is necessary to restore the mouth’s natural protective mechanisms. Reducing the frequency of consuming acidic beverages and sugary snacks also limits the fuel available for decay-causing bacteria.