Teeth lose surface material steadily over a lifetime, and the change alters proportions rather than just brightness. Dentists separate wear into distinct mechanisms because each one leaves a different pattern.
Attrition comes from tooth against tooth
Attrition is mechanical wear produced when opposing teeth contact each other. It shows up as flattened biting surfaces and shortened edges that match between the upper and lower arches.
Because it depends on contact, attrition follows the bite pattern. The teeth that meet first and hardest wear fastest, which is why the front edges often flatten before the back teeth do.
Clenching and grinding raise the amount of contact time well beyond normal chewing. That is the common reason attrition appears far earlier than age alone would predict.
Erosion comes from acid
Erosion is chemical loss of mineral from the tooth surface, driven by dietary or stomach acid. It does not require contact and can affect surfaces no other tooth touches.
The pattern differs accordingly. Eroded teeth often show smooth, cupped hollows and a glassy surface rather than the sharp flat facets that mechanical wear produces.
Erosion also thins enamel broadly instead of at contact points. Front teeth can become noticeably more transparent at the edges as the enamel loses thickness.
Abrasion comes from outside objects
Abrasion is wear from something other than teeth, most often a toothbrush used with heavy pressure. It concentrates near the gumline, where enamel is thinnest.
The resulting notches sit at the neck of the tooth rather than the biting edge. Their placement is what distinguishes them from the other wear patterns during an examination.
Habits involving objects held between the teeth produce their own localized notches. The shape of the defect often points to its cause more reliably than the patient's account.
Why proportion drives appearance
A smile reads partly through the width-to-height ratio of the front teeth. As edges shorten, teeth appear squarer, and the ratio moves away from what the eye expects.
Shortened front teeth also show less at rest and during speech. Reduced tooth display is one of the strongest visual markers of age in a smile.
Color changes at the same time, since thinning enamel reveals more dentin. Wear therefore shifts both shape and shade together, compounding the visual effect.
Why the cause is assessed before the appearance
Rebuilding worn teeth without identifying the mechanism leaves the cause running. Restorations placed into a heavy grinding pattern face the same forces that damaged the original tooth.
Examination includes checking how the teeth meet, looking for signs of acid exposure and reviewing habits. Some acid sources are medical and belong with a physician rather than a dentist.
Anyone noticing shortening or sensitivity in their front teeth should have it examined, because early wear is easier to manage than advanced wear.