Dental veneers are thin, custom-made shells of porcelain or composite resin bonded directly to the front surface of teeth. Their primary function is cosmetic, concealing issues like discoloration, minor misalignment, or chipped enamel to create a uniform appearance. The decision to receive veneers represents an irreversible alteration to the underlying tooth structure, which requires careful consideration of the long-term changes involved.
The Necessary Reduction of Enamel
The application of a veneer requires the physical preparation of the natural tooth, not just an overlay. A small amount of the outermost layer, the enamel, must be precisely removed to ensure the final restoration does not look bulky or unnatural. This reduction creates the necessary space for the veneer material.
For traditional porcelain veneers, preparation typically involves removing 0.3 to 1.0 millimeter of enamel, depending on the tooth’s position and shape. This removal prevents an over-contoured appearance and creates a roughened surface that promotes a strong chemical bond with the adhesive. Since enamel does not regenerate, this preparatory step is permanent, meaning the tooth will always require a protective covering.
Immediate Post-Preparation Effects
Immediately following enamel reduction, the tooth loses a portion of its hard, protective outer shell. This preparation can sometimes expose the underlying dentin, which contains microscopic tubules leading directly to the tooth’s nerve. This exposure is the primary cause of immediate post-preparation effects.
It is common to experience temporary sensitivity to external stimuli, such as cold air or hot and cold foods, while awaiting the final bonding of the permanent veneers. Dentists typically place temporary veneers to protect the exposed surface and manage sensitivity during the two-to-three-week fabrication period. The preparation structurally alters the tooth, making it dependent on the veneer to act as the new functional and aesthetic layer.
Long-Term Vulnerability and Decay Risk
While the veneer material is impervious to decay, the natural tooth structure underneath remains susceptible to secondary caries. This long-term risk occurs primarily at the margins, the boundaries where the veneer meets the natural tooth surface, often near the gum line. If the bond weakens or the restoration is poorly fitted, bacteria can penetrate this marginal gap, leading to leakage and decay.
Meticulous oral hygiene, particularly flossing, is mandatory to prevent plaque accumulation at these vulnerable margins. Decay developing beneath a veneer is challenging for a dentist to detect during routine checkups, as the restoration covers the affected area. If secondary caries is not caught early, it can progress deep into the dentin, necessitating the removal of the veneer for treatment. In rare cases of extensive decay, the pulp may become infected, requiring a root canal procedure to save the tooth.
The Replacement Process for Veneers
Veneers are not permanent solutions; they have a typical lifespan of 10 to 15 years before needing replacement due to wear, chipping, or marginal degradation. Once a tooth has undergone enamel reduction, it is no longer structurally sound or aesthetically acceptable to be left uncovered. Therefore, the commitment to veneers is lifelong, as the prepared tooth must always be protected by a restorative covering.
Replacing a veneer involves the careful removal of the old restoration, which is often tightly bonded to the tooth structure. Specialized instruments are used to fracture or grind away the existing material while minimizing further damage to the underlying natural tooth. The tooth is then cleaned, and sometimes additional preparation is performed to ensure the new veneer fits perfectly. This process underscores the permanent nature of the initial decision, as the tooth cannot revert to its original state.