Dental veneers are thin, custom-made shells of tooth-colored material bonded permanently to the front surface of teeth to improve appearance. They are used to correct issues like discoloration, chipping, or gaps. Veneer strength depends primarily on the material used and the level of care they receive after placement.
The Materials That Define Veneer Strength
The inherent strength of a veneer is determined by whether it is fabricated from ceramic porcelain or composite resin. Porcelain veneers are significantly stronger, utilizing a high-grade ceramic material that is layered and fired at extreme temperatures during fabrication. This process creates a dense, glass-like structure highly resistant to fracture and surface wear. Porcelain’s hardness measures around 7 on the Mohs hardness scale, which is harder than natural tooth enamel.
Composite resin is a mixture of plastic and finely ground glass filler particles, sculpted directly onto the tooth or made indirectly in a lab. This material is softer and more prone to wear, with a hardness rating closer to 5 on the Mohs scale. While composite veneers are less durable, they are easier and less expensive to repair if a chip or crack occurs.
Longevity Expectations and Typical Lifespan
The durability of veneers is measured by their expected lifespan. Porcelain veneers generally last between 10 to 15 years, often longer with diligent care. Composite resin veneers have a shorter expected lifespan, usually requiring replacement within five to seven years because the material is more susceptible to staining and degradation.
Failure is often not due to a catastrophic fracture of the material, especially porcelain. Instead, the typical mode of failure is the deterioration of the marginal seal or the adhesive bond between the veneer and the tooth surface. Degradation of the bonding cement allows microleakage, which is the infiltration of bacteria and fluids that compromises the restoration’s integrity.
Factors That Compromise Strength and Integrity
Veneers are designed to withstand normal biting forces, but excessive or concentrated stress compromises their strength. Parafunctional habits, such as bruxism (involuntary teeth grinding) or clenching, subject veneers to forces far exceeding normal chewing. Bruxism is a major contributor to veneer failure, increasing the risk of both fracture and debonding.
These habits introduce high shear and compressive forces that weaken the adhesive bond over time, leading to micro-cracks or detachment. Biting down on hard objects, such as ice, hard candies, nuts, or non-food items, applies concentrated stress at a single point. Because veneers are thin, this localized force can exceed the material’s fracture resistance, resulting in chipping or cracking.
Poor initial placement or inadequate preparation of the underlying tooth structure also compromises strength, as the weakest point of the restoration is always the bond to the tooth.
Maintaining Veneer Strength Through Proper Care
Proactive maintenance is necessary to ensure the long-term strength of a veneer. Daily care involves using non-abrasive dental products, specifically toothpaste with a low Relative Dentin Abrasivity (RDA) score, ideally under 70. Highly abrasive toothpastes, such as many whitening formulas, can create microscopic scratches that dull the finish and make the veneer more susceptible to staining and wear.
For individuals with a history of clenching or grinding, wearing a custom-fitted nightguard preserves veneer strength. The nightguard acts as a protective barrier, distributing the intense, involuntary forces of bruxism evenly across the dental arch. This prevents the concentrated stress that leads to chipping, cracking, or the breakdown of the adhesive bond.
Routine dental examinations also allow a professional to detect early signs of marginal deterioration or bonding failure before they become noticeable problems.