Teeth affected by bulimia have a distinct appearance: they look thin, translucent, and worn down, especially on the inner surfaces and biting edges. The damage comes from repeated exposure to stomach acid, which has a pH low enough to dissolve tooth enamel with every purging episode. Over time, this creates visible changes that dentists can often recognize on sight.
How Bulimia Changes the Appearance of Teeth
The most characteristic sign is erosion on the inner (tongue-side) surfaces of the upper front teeth. Stomach acid contacts these surfaces first and most intensely during vomiting, so they lose enamel faster than any other teeth. As the enamel wears away, the edges of the front teeth become thin and almost see-through, sometimes developing a glassy or translucent look. The teeth may also appear shorter over time as enamel is lost from the biting edges.
The worn surfaces have a specific texture. Rather than looking sharp or flat (as you’d see from teeth grinding), acid erosion creates a soft, rounded, satin-like appearance. On the chewing surfaces of back teeth, small shallow dips called “cupping” can form where the enamel has dissolved unevenly. These concave spots collect staining and are visible during a dental exam.
As enamel thins, the layer underneath it, called dentin, starts to show through. Dentin is naturally yellow, so teeth affected by bulimia often look darker or more yellow than they did before, even though the person hasn’t changed their diet or habits. The contrast between remaining white enamel at the gum line and yellowed exposed dentin lower on the tooth is a telltale pattern. Teeth may also chip or crack more easily because the enamel that protects them has been compromised.
Where the Damage Shows Up First
The location of erosion follows the path of the acid. Regurgitated acid primarily damages the inner and chewing surfaces of teeth. The upper front teeth take the worst hit because they sit directly in the path of vomit as it exits the mouth. This is why bulimia often devastates the length and inner thickness of these teeth before damage becomes obvious elsewhere.
Back teeth lose enamel on their chewing surfaces, and the fillings in those teeth may start to sit higher than the surrounding tooth structure. This happens because metal or composite fillings don’t dissolve in acid the way enamel does, so as the natural tooth erodes around them, the fillings appear to “rise” above the surface. Dentists sometimes call these “raised amalgams,” and they’re a recognizable clue.
Changes Beyond the Teeth
Bulimia affects the entire mouth, not just the teeth. Gums often become red, irritated, and prone to bleeding. Research comparing people with eating disorders to matched controls found significantly higher rates of gum recession (gums pulling away from the teeth) and gingivitis. The combination of acid exposure, inflammation, and sometimes aggressive toothbrushing after purging accelerates this recession, exposing sensitive root surfaces.
One of the most visible facial signs is swollen salivary glands, particularly the parotid glands that sit just in front of each ear along the jawline. This painless swelling gives the lower face a puffy, rounded look sometimes described as “chipmunk cheeks.” Studies using ultrasound have found parotid glands enlarged by an average of 36% in people with bulimia compared to controls, and the degree of swelling correlates with how frequently someone purges. Prevalence estimates for this swelling range widely, from 8% to 68% of people with bulimia, depending on how it’s measured.
The inside of the mouth can also show signs. The soft palate and throat may appear chronically red or irritated. Dry mouth is common because repeated vomiting disrupts normal saliva production, and saliva is the mouth’s primary defense against acid. Less saliva means less natural protection, which accelerates the erosion cycle.
Russell’s Sign on the Hands
Though not a dental sign, dentists and doctors look for a related physical marker: calluses or scars on the knuckles of the dominant hand. Known as Russell’s sign, these form when the knuckles repeatedly scrape against the upper teeth during self-induced vomiting. They appear as crusted, thickened patches of skin on the back of the hand, typically over the index and middle finger knuckles. Not everyone who purges develops them, but when present alongside dental erosion, they strongly suggest bulimia.
How Sensitivity and Function Change
As enamel erodes, teeth become increasingly sensitive to hot, cold, and sweet foods. This happens because dentin contains tiny tubes that lead toward the nerve, and once enamel no longer covers them, temperature changes travel straight to the nerve endings. Many people with bulimia-related erosion notice that biting into cold or acidic foods causes sharp, immediate pain that wasn’t there before.
Chewing can also become less efficient. Shortened, thinned front teeth don’t bite through food as cleanly, and cupped back teeth lose their ability to grind effectively. In advanced cases, the bite itself can shift as teeth wear unevenly, changing how the upper and lower jaws come together.
What Dental Repair Looks Like
The type of restoration depends on how far the erosion has progressed. Mild to moderate enamel loss can be rebuilt with composite resin, a tooth-colored material bonded directly to the damaged surfaces. This is relatively conservative and preserves most of the remaining tooth structure.
More severe damage, where teeth have lost significant height or structural integrity, typically requires porcelain veneers or full-coverage crowns to restore both appearance and function. In the most advanced cases, teeth may be too damaged to save and need extraction, with bridges or implants replacing them. Any restorative work is most successful after purging has stopped, because ongoing acid exposure will break down new dental work the same way it destroyed the original enamel.