The question about the “grit sandpaper” dentists use for teeth points to a specialized area of professional dental care known as dental abrasion. It is important to understand that no dentist uses the sandpaper found in a hardware store on a patient’s teeth. Dental abrasion is a highly controlled technique using specialized, non-toxic materials to smooth, contour, and polish the surface of natural teeth or restorations. This procedure is performed strictly by trained professionals, and any attempt to use non-dental abrasive materials for self-treatment poses a serious and irreversible risk to the enamel and overall oral health.
The Critical Distinction: Dental Tools vs. Hardware Abrasives
The materials used for sanding wood or metal are fundamentally different from the abrasives designed for use inside the human mouth. Hardware sandpaper utilizes abrasive grains like garnet, flint, or industrial-grade aluminum oxide, attached to a backing with adhesives that are neither sterile nor safe for ingestion. These products often contain toxic chemical binders, dyes, and metallic contaminants unsuitable for the oral environment. The particle size is also far too coarse for the microscopic precision required in dentistry, where small scratches can trap bacteria.
Dental abrasives are manufactured under strict conditions to ensure biocompatibility and sterility. The abrasive agents are composed of chemically pure materials such as diamond powder, specialized aluminum oxide, or silicon carbide, bonded to a flexible backing or integrated into burs and points. The backing material is designed to be non-toxic and flexible, such as specialized plastic or thin metal strips, allowing for safe access between teeth. This ensures the material is effective at removing dental material and safe when contacting oral tissues and saliva.
Professional Abrasive Tools and Their Functions
Dentists employ a variety of specialized tools that perform the function of “sandpaper” but with far greater precision and control. One common system involves coated abrasive discs, such as the widely known Sof-Lex system, which are small, flexible, color-coded discs used with a low-speed handpiece. These discs are designed for contouring and finishing the broad surfaces of a restoration, like a composite filling. They allow the clinician to refine the shape of the material to match the natural tooth anatomy.
To address the areas between teeth, dentists use interproximal finishing strips, which are thin, flexible plastic or metal strips coated with abrasive particles. These strips are manually pulled back and forth to smooth the contact point and side surfaces of a restoration without damaging the adjacent tooth. For more aggressive material reduction, specialized diamond burs and carbide burs are used. Diamond burs, featuring microscopic diamond crystals, are highly effective for cutting and shaping hard tissues like enamel, while carbide burs offer high cutting efficiency for bulk removal.
Understanding Dental Abrasive Grit (Micron vs. Mesh)
The way dental abrasives are measured technically differentiates them from commercial sandpaper. Traditional sandpaper uses a mesh system, or grit number, where a lower number indicates a coarser grit. Dental abrasives, however, are primarily measured in microns (\(\mu\)m), which refers to the actual size of the abrasive particle. This measurement reflects the microscopic precision necessary for dental work.
The grit sizes used in dentistry span a wide, precisely controlled range, moving from particles as large as 100 \(\mu\)m for coarse shaping down to 5 \(\mu\)m or less for ultra-fine polishing pastes. For context, a 100 \(\mu\)m particle is used for gross reduction and initial contouring. The finer range, such as 30 \(\mu\)m, is considered a finishing abrasive, used to smooth the surface after initial shaping.
This sequential abrasion process is fundamental to the dental procedure. The dentist progresses from a coarse abrasive to medium, fine, and finally, an ultra-fine particle size to achieve optimal surface smoothness. This technique ensures that the deep scratches left by larger particles are systematically removed by successively smaller ones. A final, high-shine polish is often achieved using pastes with particles in the 0.5 to 4 \(\mu\)m range, leaving a surface so smooth it resists the accumulation of bacterial plaque.
Clinical Applications: When and Why Abrasives Are Used
The precise use of dental abrasives is necessary across several clinical procedures to ensure the longevity and health of dental work. The most common application involves finishing and polishing composite restorations (tooth-colored fillings). After the filling material is placed, abrasives remove excess material, refine the contour to match the bite, and establish a smooth margin where the filling meets the natural tooth structure.
A smooth surface provides a healthy oral environment by making the restoration less prone to plaque adhesion and staining. Abrasives are also utilized in minor enameloplasty, which involves the subtle reshaping of tooth edges to correct small irregularities or chips. Specialized abrasive strips and discs are further used during Interproximal Reduction (IPR), a controlled orthodontic procedure that creates small amounts of space between teeth to aid alignment.