The first permanent molar, commonly known as the six-year molar, is a permanent tooth, not a temporary baby tooth. This tooth is the first adult molar to emerge, marking the beginning of the mixed dentition stage when a child has both primary and permanent teeth. Officially named the First Permanent Molar, its early arrival and function are important for long-term oral health.
The Permanent Status of the Six-Year Molar
The First Permanent Molar is classified as an accessional tooth, meaning it does not replace an existing primary tooth but erupts into a new space at the back of the jaw. All other permanent teeth, except the molars, are succedaneous, meaning they replace a baby tooth.
There are four first permanent molars, with one located in each quadrant of the mouth, behind the last baby molar. It begins its emergence around age six, varying between five and seven years old, which is the reason for its common nickname. Once it fully erupts, this tooth becomes a lifelong member of the permanent dentition.
Eruption and Identification
The typical eruption of the First Permanent Molar occurs between the ages of six and seven, often without the child losing a primary tooth beforehand. This silent emergence at the very back of the mouth is the primary reason for the common misconception that it is a baby tooth.
Parents and caregivers may not realize a new tooth has appeared because no gap is created by a shed primary tooth to draw attention to the area. Unlike the incisors, the new molar can be mistaken for the second primary molar already present in the arch. The timing of its eruption can sometimes coincide with the loss of the first baby teeth, further confusing its permanent status.
Unique Function and Importance
The First Permanent Molar acts as the “keystone” or “anchor” of the dental arch, playing a dominant role in the development of the entire bite. Its early eruption establishes the vertical dimension of the bite and helps guide the position of all the other permanent teeth that follow. The relationship between the upper and lower first permanent molars is the foundation for proper occlusion, or how the upper and lower teeth meet.
This tooth bears the majority of the chewing forces due to its large surface and robust root structure. The maxillary, or upper, first molars typically have three roots, while the mandibular, or lower, first molars have two roots, providing maximum anchorage in the jawbone.
If this tooth is lost prematurely due to decay, it can lead to a collapse of the dental arch, causing neighboring teeth to tilt or shift and disrupting jaw alignment. This shift can result in long-term problems with chewing efficiency and can complicate future orthodontic treatments.
Protecting the First Permanent Molar
Because the First Permanent Molar is the first permanent tooth to emerge and is positioned at the back of the mouth, it is susceptible to developing dental decay. Its chewing surface contains deep pits and fissures, narrow grooves that easily trap food debris and bacteria, even with regular brushing. The newly erupted enamel is also not yet fully mature, making it vulnerable to acid attacks.
Dental Sealants
One effective preventive measure is the application of dental sealants, a thin, protective coating made of plastic resin material. Sealants are painted onto the chewing surfaces shortly after the tooth fully erupts to create a smooth barrier that seals off the deep grooves. This procedure is quick, painless, and can provide protection against cavities for up to ten years, though they require periodic checks for chipping or wear.
Focused brushing with fluoride toothpaste is also necessary, as the tooth’s far back location makes it a difficult target for a young child’s toothbrush.