Types of Cavities: What They Are, Where They Form, and How Each Is Treated

Cavities are permanently damaged areas in a tooth's hard surface that develop into holes over time. They form when bacteria in your mouth produce acids that wear away enamel, and they're one of the most common dental problems for people of all ages. This article covers the different types of cavities, what to watch for, and how each is treated. 

The Three Main Types of Cavities 

Pit and Fissure Cavities

Pit and fissure cavities form in the deep grooves on the chewing surfaces of back teeth, primarily molars and premolars. They're the most common type of cavity, especially in children and teenagers, because the narrow pits and fissures in molars are difficult to clean thoroughly. Even with good brushing habits, plaque and food debris can accumulate in those grooves and slowly erode the enamel.

Signs of a pit and fissure cavity include:

• Visible dark spots or discoloration in the grooves of a molar
• Sticky or rough feeling when you run your tongue across the chewing surface
• Sensitivity to sweet foods or cold temperatures

When caught early, a small pit-and-fissure cavity is treated with a tooth-colored composite filling in a single visit. More advanced decay may require a larger filling or an inlay.

Smooth Surface Cavities

Smooth surface cavities form on the flat outer surfaces of teeth, most often on the sides of teeth where they contact each other, or along the gumline. In most cases, cavities between teeth are only detectable on dental X-rays, which is one of the strongest reasons routine checkups with X-rays matter.

Signs include:

• White or brown spots on tooth surfaces
• Sensitivity along the gumline
• Visible darkening between teeth in more advanced cases.

Early-stage smooth surface cavities may be reversible with fluoride treatment. Once a cavity has fully developed, a composite filling is standard. Cavities between teeth may require a slightly more involved procedure to access and fill, but remain routine treatment for an experienced dentist.

Root Cavities

Root cavities form on the root surfaces of teeth, the part of the tooth below the gumline that becomes exposed when gums recede. They're most common in older adults, because gum recession tends to increase with age, and in patients with periodontal disease or chronic dry mouth. Saliva helps neutralize acids in the mouth, so patients who produce less of it are at higher risk for decay on root surfaces.

Unlike the crown of the tooth, root surfaces have no enamel layer. That makes them significantly more vulnerable to acid attack, and decay can progress faster here than it would on an enamel-covered surface.

Signs of a root cavity include:

• Sensitivity along the gumline
• Visible discoloration on the root surface
• A soft or rough texture that a dentist can detect when probing the area.

Composite fillings are the standard treatment for accessible root cavities. More advanced cases involving deeper decay may require more extensive restorative dental work, and in severe situations, extraction may be necessary.

Quick Fact: Did you know, 91% of all Americans have some
type of cavity in their teeth? 

What Is a Small Cavity and Can It Be Reversed?

A small cavity is early-stage tooth decay. It's decay that has progressed through the outer enamel layer but has not yet reached the dentin underneath. At the very earliest stage, a cavity may appear as a white, chalky spot on the tooth surface. As decay continues, the spot may darken to brown or gray. In the grooves of a molar, it might look like a very small dark pit.

Here's the part that surprises most people: the white spot stage is the only point at which decay can actually be reversed. If a white spot lesion is caught before a true hole forms, fluoride treatment, combined with improved brushing and flossing, can remineralize the enamel and prevent the cavity from progressing. But once decay has penetrated the enamel and formed a hole, it cannot reverse on its own. At that point, a filling is the only option.

How Cavities Are Treated by Severity

Early-Stage Cavities (Enamel Only)

• If decay is still in the white spot stage before a hole has formed, fluoride treatment can remineralize the enamel and reverse the damage. This is the only cavity stage where that's possible.
• If a small hole has formed in the enamel, a tooth-colored composite filling is the standard treatment. It's typically completed in one visit, takes about 30 to 60 minutes, and preserves as much healthy tooth structure as possible.

Moderate Cavities (Into the Dentin)

• When decay has reached the dentin beneath the enamel, a larger composite filling, an inlay, or an onlay may be needed, depending on how much of the tooth surface is affected.
• Patients at this stage often begin to notice sensitivity or mild pain when eating, drinking, or biting down — a sign that the decay is getting closer to the nerve.

Severe Cavities (Reaching the Pulp)

• If decay reaches the pulp — the innermost tissue that contains the tooth's nerves and blood vessels — a root canal is needed to remove the infected tissue and protect the tooth from further damage.
• After a root canal, a dental crown is placed to restore the tooth's shape, function, and strength.
• If the tooth is too damaged to save, extraction followed by a dental implant or bridge may be the best path forward to restore your smile and protect surrounding teeth.

From Small Fillings to Full Restorations, Gentle Dental Has You Covered

No matter what type of cavity you're dealing with, one thing is true across the board: catching it early keeps treatment simple, fast, and affordable. Regular cleanings and X-rays are the most reliable way to catch decay before it becomes a bigger problem.

At Gentle Dental, you'll find preventive care and restorative treatment under one roof. From routine exams and cleanings that catch cavities early to tooth-colored fillings, dental crowns, and root canal treatment when more is needed. Gentle Dental accepts most insurance plans, and preventive visits are typically covered at 80 to 100%.

Schedule your next exam and cleaning at a Gentle Dental location near you.