The number of human teeth is not fixed; it undergoes two significant replacements as we grow.
Phase 1: Primary Dentition (Approx. 6 months - 6 years old)
Number of teeth: A total of 20 teeth.
Condition: This is our first set of teeth. They are smaller with thinner enamel but reserve space for the future permanent teeth. Caring for primary teeth is crucial for chewing, speech, and facial development.
Phase 2: Mixed Dentition (Approx. 6 - 12 years old)
Condition: This is the "teeth-changing period" where primary teeth gradually fall out and permanent teeth erupt in sequence. Both primary and permanent teeth coexist in the mouth.
Phase 3: Permanent Dentition (Approx. 12 years old and beyond)
Number of teeth: A total of 28-32 teeth.
28 permanent teeth (excluding wisdom teeth) form the foundation for good chewing function.
Wisdom teeth (0-4) typically erupt between ages 17-25. For many, they cannot erupt properly due to lack of space.
Condition and Challenges: Permanent teeth are a non-renewable resource, requiring lifelong defense against decay, gum disease, and wear.
Regarding Tooth Loss in Old Age: It is important to clarify that tooth loss is not an inevitable result of aging. In later years (typically referring to age 60 and above), the primary causes of tooth loss are long-accumulated severe periodontal disease or dental caries, not age itself. While factors like gum recession, reduced saliva, and systemic diseases can increase oral health risks with age, achieving the "8020" goal (having at least 20 functional teeth at age 80) is entirely possible with consistent, effective care and regular dental check-ups.
The Core Principle: Regardless of age, lifelong cleaning, care, and professional check-ups are the key to safeguarding dental health and preventing premature tooth loss.