Permanent Teeth (also known as adult teeth)
In my last blog, I was talking about primary teeth (baby teeth) and their care. This one is going to be about permanent teeth (adult teeth).
The term permanent teeth is a misnomer as the teeth are not really permanent. They are subjected to decay, gum disease, chip and fracture which all can lead to tooth loss.
The first adult teeth usually come in at about 6 years old. They are known as the “first molars,” or the “six-year molars”. There is a range of time for the first molars to come in – from as early as 5 to as late as 7 years old.
They come in at the back of the mouth, behind the last baby teeth. They do not replace any primary teeth.
At around the same time the first molars erupt, the lower primary central incisors (the two lower front teeth in the middle) start to become loose as the adult central incisors are erupting and melting the roots of the baby teeth away. The two central lower baby teeth eventually fall out and replaced with the two adult incisors. The two adult teeth usually erupt from behind the two baby teeth. Once the baby teeth are gone, the two central incisors will continue to erupt and move forward until they are in alignment with the other teeth in the arch. Because the adult teeth are bigger in size than the baby teeth, it is healthy and usual to have spaces between the baby teeth to give rooms for the adult teeth to grow into. When there are not enough spaces for the adult teeth to erupt into, crowding of adult teeth will ensure. The are either crooked, rotated, in front or behind the adjacent teeth and even impacted (stay inside the jaw bone).
There is a sequence for the replacement of the baby teeth with adult teeth at different stages (see the diagram). By the time the kids are 12 years old, all the baby teeth are gone and replaced with the adult teeth for most kids. Girls usually mature earlier than boys and so girls usually have full adult teeth earlier than boys. Some children can have all baby teeth replaced by adult teeth the age of 10 and some do not have the process completed by the age of 15.
Besides the replacement of baby teeth with adult teeth in sequence as part of the growth of children, the jaws also grow at the same time. The growth of the jaws can well be into their late teen in boys – 19 to 20 years old. Girls usually pretty much done with their growth by the age of 14 to 15.
It’s okay for children to wiggle their primary teeth if they are loose. But if it is not loose, do not use force to pull out a tooth that is not ready to come out. The roots of the baby teeth may be broken inside the bone and can impede the eruptions of the adult teeth. When a tooth comes out at the right time, there will be very little bleeding.
Occasionally, some children may be missing some adult teeth congenitally. The most common congenitally missing teeth are the lower second premolars, followed by the upper lateral incisors, and the upper second premolars. In those cases, the baby teeth where the adult teeth are missing are retained in place. The retained baby teeth usually look awkward due to the size and shape among the adult teeth. They often have decay and excessive wear as well. Treatments can be fillings and bonding to create the adult teeth look and size. Crowning the teeth with porcelain or zirconia can also be an option. Bridge or implant supported crowns are another choice to fill up the spaces after the retained baby teeth have been removed.
Adult front teeth usually first came in with undulated incisal edge (not flat). The reason is because of the mamelons.
The mamelons do not need to be smoothed down or flattened by dentist as they will be worn down soon after the upper and lower incisors are in contact and in function.
Permanent teeth often look more yellow than primary teeth. This is normal. The adult teeth will become more yellow or brownish as the teeth pick up colours from the food and drinks. If the yellow or dark stain cannot be removed by having your teeth cleaned by your dentist or hygienist, then bleaching or whitening of the enamel peroxide is usually very effective and cost effective (see my blog on teeth whitening).
Sometimes, your teeth can have blotches or lines of dark brown, greyish or white shade/colour. Those could be due to fluorosis (too much fluoride), tetracycline stain or hypocalcification. Ask your dentist about this when you go for a dental examination. Treatments can be micro abrasion, bleaching, composite resin bonding and porcelain veneers.
If the permanent teeth are not straight, crooked, crowded or not aligned with each other, braces with wire or Invisalign trays can be used to bring the teeth straight. In some cases, even the teeth are straight and aligned but the facial profile is not pleasing (example, short or long lower jaw) or the smile is not nice (like overly erupted upper teeth with gummy smile), orthognathic surgery can be performed to reset the upper and/or lower jaw to create a harmonious, balance relationship with nice straight profile.
Once the permanent teeth are erupted, they are subjected to different common oral disease like cavities, gum disease, wear, fracture, chip, crack, trauma, injury, toothbrush abrasion, stain and chemical erosion etc. The teeth cannot be permanent if they are being neglected. Good home oral hygiene care, proper nutrition and regular visit with your dentists are needed in order for them to stay healthy and functional.
Dr. Wong at Affinity Dental Care has over 30 years of professional experience, he is passionate about providing you and your family a high standard of oral and dental care.