Worn Teeth

Under normal circumstances a layer of enamel covers your teeth. This enamel is very hard and protects the tooth from daily wear and tear. 

However your tooth enamel may be worn away in several ways:

Attrition

Attrition is the gradual loss of enamel through "wear". A small amount of attrition may be caused by normal speaking and eating, but this typically doesn't produce excessive wear. More extreme cases of attrition are typically caused by bruxism, the grinding or clenching of teeth against each other. Bruxism typically occurs at night while the patient sleeps, so often the patient is unaware of the grinding or enamel loss. The first line of defense against bruxism is a night guard.  

Abrasion

Abrasion is the wearing away of tooth enamel by a foreign object. Common causes of abrasion are:

Brushing too hard - When using a soft bristle tooth brush, it isn't necessary to press hard. The soft bristles will bend into all desired positions with minimum pressure. 

Unnatural biting habits - Fingernail biting, chewing on pens or pencils, holding needles or pins between the teeth, etc.
Oral jewelry - Patients with pierced lips and/or tongue often wear away the enamel on adjacent teeth 

Erosion

Erosion is the chemical wear of tooth enamel. Typically this kind of wear is caused by an acid. Citric acid is one of the most common agents. Citrus fruit (lemons, limes, oranges, grapefruit) contain citric acid, as do most soft drinks and citrus juices. Some candies also contain citric acid. Many soft drinks contain additional harmful acids. Coffee and tea also contain corrosive acids. Bulimic individuals (people who intentionally and repeatedly induce vomiting) also expose their teeth to very strong stomach acids.

Occasional exposure to most dietary acids is rarely a problem, but repeated exposure to high levels of these acids can cause premature wear. Some common habits to avoid are:

 -Regularly sucking on lemons or limes

 -Regularly eating or sucking on candies, especially "sour" candies as they often contain sugar and citric acid!

 -Drinking several soft drinks daily, even "diet" soft drinks

 -Drinking several cups of coffee or glasses of tea daily

Even if you only occasionally eat or drink highly acidic foods, it's a good idea to at least rinse your mouth with fresh water when you are finished. This is to reduce the amount of time that your teeth are exposed to the acids.