Dentin sealers are materials regularly used in dentistry to protect teeth during various procedures. These sealers form a protective layer on the tooth’s underlying structure, playing a fundamental role in maintaining tooth health during and after dental work.
What is Dentin Sealer?
A dentin sealer is a specialized material applied to the dentin, the porous layer of tooth structure located beneath the enamel and cementum. It forms a protective barrier over the exposed dentin surface. This material prepares the tooth for the placement of fillings, crowns, or other dental restorations. Immediate dentin sealing involves applying a dentin bonding agent to freshly cut dentin during tooth preparation for indirect restorations like inlays, onlays, or crowns.
Why Dentin Sealers Are Used
Dentin sealers are applied for several reasons, primarily to enhance patient comfort and ensure the longevity of dental restorations. One significant benefit is preventing tooth sensitivity, particularly to hot, cold, or pressure stimuli. This occurs because the sealer blocks the microscopic openings of the dentinal tubules, which are tiny channels that connect to the tooth’s pulp.
Dentin sealers also protect the pulp, the innermost part of the tooth containing nerves and blood vessels. By creating a barrier, they shield the pulp from irritation caused by bacteria, oral fluids, and chemicals present in restorative materials, helping maintain the vitality of the tooth.
Dentin sealers also improve the bond strength between the tooth structure and the dental restoration, leading to a stronger and more durable repair that is less likely to dislodge over time. This improved bond contributes to the overall success and lifespan of the dental work.
The sealers also play a role in reducing microleakage, which is the seepage of bacteria and fluids under the restoration. They prevent these substances from infiltrating the tooth, thereby minimizing the risk of secondary decay and potential restoration failure. This tight seal helps preserve the integrity of the tooth and the restoration.
How Dentin Sealers Work
Dentin sealers achieve their protective and adhesive effects through specific mechanisms involving the tooth’s microscopic structure. These materials penetrate the minute tubules within the dentin. The sealer either physically blocks these tubules, creating a barrier, or chemically bonds to the dentin, or a combination of both.
For many modern dentin sealers, particularly those containing adhesive monomers, they infiltrate the demineralized collagen network of the dentin. This infiltration creates a “hybrid layer”. This hybrid layer is a transitional zone that integrates the resin with the tooth, forming a strong, integrated seal between the dentin and the restorative material. This process allows the bond to develop and mature over time, leading to higher bond strengths.
Types of Dentin Sealers
Various types of dentin sealers are available, each with distinct compositions and primary functions. Adhesive sealers, also known as bonding agents, are widely used to create a strong bond for composite fillings and other restorations. These materials often contain resin monomers that penetrate the dentin and form a hybrid layer.
Desensitizing sealers are specifically formulated to reduce tooth sensitivity. These sealers help occlude or block the dentinal tubules, thereby diminishing the flow of fluid within them and reducing nerve irritation. Newer desensitizers may also incorporate nano-hydroxyapatite or zinc-containing compounds to achieve similar effects.
Glass ionomer-based sealers are known for their ability to chemically bond to tooth structure through a chelation reaction between their carboxyl groups and the calcium in the tooth’s hydroxyapatite crystals. These sealers also release fluoride, which can help in the remineralization of surrounding tooth surfaces and provide long-term protection against decay.