Molars are large, flat teeth located at the back of the mouth, designed for crushing and grinding food. Humans experience different sets of teeth throughout their lives, starting with primary teeth in childhood and transitioning to permanent teeth in adulthood. This progression involves the natural loss of some molars, while others are intended to remain for a lifetime.
Primary Molars and Childhood Loss
Children develop a set of 20 primary, or “baby,” teeth, which include molars. Children have eight primary molars: two on each side of the upper and lower jaws. These primary molars play an important role in chewing and maintaining space for the permanent teeth that will eventually replace them.
The natural process of losing primary molars begins as children grow, making way for the emerging permanent teeth. Primary molars usually start to shed between ages 9 and 12. This shedding occurs as the roots dissolve due to pressure from the underlying permanent teeth, causing them to loosen and fall out.
Permanent Molars and Adult Teeth
As primary teeth are naturally shed, they are replaced by a set of permanent teeth. Adults have 32 permanent teeth, which include up to 12 molars. These molars consist of first, second, and third molars, commonly known as wisdom teeth. The first permanent molars usually emerge around age 6, followed by second molars around age 12. These molars do not replace any primary teeth but erupt behind them.
The third molars, or wisdom teeth, are the last to appear, emerging between the ages of 17 and 21. Not everyone develops all four wisdom teeth, and some people may not develop any at all. Wisdom teeth are often removed due to issues like misalignment, impaction, or crowding. The human jaw has evolved to be smaller, sometimes lacking sufficient space for them. If wisdom teeth are removed or never develop, an adult’s molar count may be eight instead of twelve, resulting in a total of 28 permanent teeth. Unlike primary molars, permanent molars are not naturally shed; they are meant to last a lifetime.
Reasons for Adult Molar Loss
Since permanent molars are not naturally lost, their absence in adults usually points to underlying health issues or trauma. One cause of adult molar loss is severe tooth decay, also known as cavities. This occurs when bacteria in the mouth produce acids that erode the tooth’s enamel, creating holes that can progress deeply into the tooth structure, leading to infection and loss if untreated. Poor oral hygiene and frequent consumption of sugary or acidic foods contribute to tooth decay.
Another reason for adult molar loss is advanced gum disease, known as periodontitis. This condition results from bacterial plaque and tartar buildup, which inflames the gums and can destroy the bone and tissues supporting the teeth. As the disease progresses, teeth can loosen and fall out because their foundational support is compromised.
Traumatic injuries to the mouth also account for adult molar loss. Accidents, such as falls, vehicle collisions, or sports-related incidents, can lead to damage like fractures or dislodgement of molars. Even seemingly minor trauma can result in damage that necessitates tooth removal to prevent further complications.