First teeth: when to start oral care — and why 'they will fall out anyway' is dangerous

Tooth decay is the most common chronic disease of childhood worldwide. It affects one in four children before age five — despite being one of the most preventable pathological processes in medicine. Its prevalence has a single explanation: parents not knowing when to start, what to use, and how.

Where oral care begins: before the first tooth

Paediatric dentistry is unanimous: oral hygiene should start before the first tooth erupts. A soft damp cloth or silicone finger brush is used to wipe gums and tongue after feeding. Goal: building a habit and mechanically reducing bacterial load.

The first tooth usually erupts between four and seven months. From that moment: a soft toothbrush and a smear of fluoride toothpaste. Per AAPD (2023) and AAP (2020) guidelines:

• First tooth to age 3: fluoride toothpaste 1,000–1,500 ppm, smear/rice grain amount (~0.1 g).
• Ages 3–6: fluoride toothpaste 1,000–1,500 ppm, pea-sized amount (~0.25 g).
• Age 6+: standard fluoride toothpaste, standard amount.

Why "they will fall out anyway" is not an argument

Primary teeth perform functions that "temporary" understates:

• Chewing and nutrition: pain from decay disrupts eating and affects growth.
• Speech: primary teeth participate in forming consonants.
• Space holders: maintain space for permanent teeth. Premature loss → neighbouring teeth shift → crowding of permanent teeth.
• Bacterial transmission: S. mutans from a decayed primary tooth colonises permanent teeth before they even erupt.

Primary tooth decay does not resolve on its own. It is a source of infection that hurts, disrupts nutrition, and seeds permanent teeth with cariogenic bacteria before they emerge.

How bacteria transfer from parents to children

Streptococcus mutans — the principal cariogenic bacterium — is transmitted vertically from mother to child through saliva. Sharing spoons, licking a pacifier, kissing on the mouth: these are the main transmission routes. Parents with active caries significantly increase a child's colonisation risk.

Research shows: the later initial S. mutans colonisation occurs, the lower the subsequent caries risk. Delayed colonisation is achievable: thorough parental hygiene, xylitol use (reduces salivary S. mutans levels), and separate utensils for the child all contribute.

Practical steps

1. Gum hygiene from birth: damp cloth or finger brush after each feeding.
2. Fluoride toothpaste from the first tooth: a smear is safe — fluorosis risk at this quantity is minimal.
3. Parents brush until age 6–8: children cannot manage technique independently before this.
4. No bedtime bottle: milk or juice next to sleeping teeth = decay. If needed — water only.
5. First dental visit with the first tooth, no later than 12 months.
6. No shared utensils: reduces S. mutans transmission.

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Sources:

• AAPD Policy on Early Childhood Caries (2023). https://www.aapd.org
• AAP. (2020). Fluoride Use in Caries Prevention. Pediatrics. https://doi.org/10.1542/peds.2020-034637
• PMC12145511 — Review of Early Childhood Caries (2025)
• Cochrane review: Preventing dental caries in children. Marinho VCC et al. (updated 2024)
• Tanzer JM, Livingston J, Thompson AM. (2001). The microbiology of primary dental caries in humans. J Dent Educ. PMID 11699974
• Saethre-Sundli HB, Wang NJ, Wigen TI. (2020). Do enamel and dentine caries at 5 years predict caries development in newly erupted teeth? Acta Odontol Scand. PMID 32189539