CAVITY RESTORATIONS

Feline oral resorptive lesions are not true cavities and are treated somewhat differently. Cavity treatment in dogs is very similar to the treatment in people. First, a dental radiograph is exposed to determine the extent of the decay and if there is root canal involvement. If there is endodontic involvement, then a root canal procedure is necessary prior to restoration. Next, using a high-speed dental bur (drill) all the diseased tooth structure is removed. Then, the cavity is prepared to accept the restoration (filling). Depending on the filling material used, an undercut is usually made to increase retention of the restorative. Next, a filling is placed in the defect. The filling is allowed to harden (cure). Finally, the restoration is finished by making the restoration conform to natural anatomy and smoothing the restoration to decrease plaque retention.

There are two basic types of restorative materials used for caries in dogs. The first is silver amalgam. This is the filling material that was used in human dentistry for years until recently. It is very hard and resistant to wear (even more than teeth are), however it does not create as good of a seal as composite fillings do. Composite fillings are the “white” fillings that most people get in cavities today. It is bonded to the tooth surface, and therefore is less likely to leak than amalgam. However it is not as tough as amalgam and can more easily be broken down. This is especially important in dogs where the bite force is much more than in people. Either material is acceptable depending on the case and operator preference. An additional restoration type is glass ionomer. This restorative is generally not strong enough for use in dogs, however will be used on occasion in areas that are low stress and susceptible to further carious decay. They may be used as a liner for composite restorations, as this will release fluoride and decrease the amount of composite needed. This is important as the composite will shrink slightly during polymerization (hardening), and this layer will decrease the amount of shrinkage.

Restoration of the carious lesion in this patient would require a gingival flap to expose the defect and x-rays to ensure no involvement with the root canal.

Feline oral resorptive lesions are treated somewhat differently. Because the teeth are so small and the dentin is not diseased, removal of tooth structure is minimal to not at all. In addition, the small size of the teeth does not allow the creation of mechanical retention by an undercut, so a restoration that bonds to the tooth must be used. After cleaning and drying the tooth, the surface is acid etched to clean the tooth and open up the enamel and dentin to increase the surface area for bonding. If a composite is used, a bonding agent is placed on the lesion. Finally, the restoration is placed, cured, and finished. The choice of restorative material is based on the size and location of the lesion and operator preference. The classic is a glass ionomer cement. These materials bond to dentin, are somewhat flowing into the lesion, and most importantly release fluoride. Fluoride is the only treatment that is shown to decrease the activity of these lesions. Flowable composites can be used as well. They are harder than glass ionomer, however they do not release fluoride. Restoration of these lesions in general is infrequently curative. Extraction is the treatment of choice in many cases.