How much do you know about the deformed central apex?

This is the 3827th article of Da Yi Xiao Hu

A few days ago, a 12-year-old girl was taken to the hospital by her father for a dental check-up. No rotten teeth were found, but a "tooth bump" appeared on the gum of the girl's lower left back tooth. The parents were confused. What caused it? After our examination, we found that it was a root inflammation (chronic apical periodontitis) caused by the fracture of the deformed central cusp. The girl said that she had mentioned to her father why there was a small point on the tooth before, but her father didn't pay attention to it. Now the child's father suddenly realized that this small point could also cause problems with the teeth.

Let’s talk about it today

This confusing deformed central apex

1. What is a malformed central cusp?

Abnormal central cusp is a developmental and morphological abnormality of teeth. It refers to a conical cusp protruding from the center of the occlusal surface of the premolar or molar or the adjacent triangular ridge of the cusp. It can be single or multiple, and most commonly occurs on the mandibular and maxillary premolars (in the normal dentition, the premolars are located from the midline, the 4th and 5th teeth from front to back, up and down, left and right, a total of 8 teeth) (Figure 1); molars are also occasionally seen, often symmetrically. After careful examination, the young lady we received was found to have abnormal central cusps on the adjacent teeth and the teeth of the same name on the opposite side (Figure 1). Abnormal central cusps are also called Oriental or Mongolian premolars. They often occur in people from China, Japan, the Philippines, Malaysia and other places. The incidence rate is 1% to 5%, and women are higher than men.

(Figure 1)

2. What are the effects of a deformed central cusp?

The height of the deformed central cusp varies, generally about 1 to 3 mm, and the tip can be pointed or blunt. In the early stage of premolar eruption between the ages of 10 and 12, when the upper and lower teeth are not occluding, the teeth are different from normal teeth in morphology and have no obvious clinical symptoms. They are often ignored and are often discovered accidentally during oral examinations. During long-term occlusion, the deformed central cusp is prone to wear or fracture, exposing the dental nerve or dentin, causing dental nerve infection, and in severe cases, inflammation of the tooth root. Just like the young lady we saw, the root of the lower left posterior tooth was inflamed and a bump appeared on the tooth (Figure 2)

(Figure 2)

In addition, since the teeth have just erupted, the roots are not fully developed (at this time the roots have only developed to about 2/3 of the root length). If an abnormal central cusp fracture occurs at this time, the growth and development of the roots will often be affected. If not treated in time, it may lead to root resorption or even premature tooth loss.

3. How can we prevent and treat the deformed central cusp?

First of all, it should be noted that not all people have deformed central cusps. Most people have relatively normal teeth. The incidence of deformed central cusps is often one in a hundred, with an incidence of 1% to 5%. If you have children aged 10 to 12 at home, you can pay special attention to check whether there are abnormal protruding small cusps on the newly erupted premolars or take your children to the hospital for regular oral examinations. The doctor will know at a glance. Once a deformed central cusp is found, you should avoid biting the affected teeth to prevent the deformed cusp from breaking, and seek medical attention as soon as possible. Oral doctors have ways to prevent deformed central cusps and treat diseases caused by deformed central cusps.

Author: Jia Shujuan, deputy chief physician of the Department of Stomatology, the Affiliated Hospital of Guangdong Medical University, ambassador for promoting healthy oral health of the China Dental Disease Prevention and Control Foundation, captain of the volunteer "Happiness Bank" YaYaLe Medical Science Service Team of the Affiliated Hospital of Guangdong Medical University, and member of the Children's Dentistry Professional Committee of the Guangdong Stomatological Association.