One Exposure, One Acid Attack
One sugar exposure triggers one acid-attack cycle.
- ~2.3 pH: Stephan curve drop (per sugar exposure)
- ~40 min: Recovery time (back above critical pH)
- 5.5: Critical pH (enamel demineralizes below this)
- Low: Cavity risk (isolated, well-buffered event)
The Stephan curve
Sugar feeds plaque bacteria almost instantly.
Enamel starts dissolving once plaque pH drops below 5.5.
One bite, one cycle
Saliva buffers the acid back toward baseline.
Why timing matters
Frequency, not amount, drives daily enamel damage.
Two Exposures, Two Attack Cycles
Two spaced exposures create two separate acid cycles.
- 2 / day: Exposures (separate acid cycles)
- 4 hrs: Gap between hits (full recovery between)
- 0%: Cycle overlap (cycles don't stack)
- Low: Cavity risk (still well within recovery)
Two separate attacks
Each exposure resets its own acid cycle.
Full recovery between snacks keeps total damage limited.
Saliva's recovery window
A four-hour gap lets minerals redeposit fully.
Still low risk
Two spaced exposures stay manageable for enamel.
Four Exposures, Overlapping Attacks
Frequent snacking overlaps acid cycles across the day.
- 4 / day: Exposures (frequent snacking)
- 75 min: Gap between hits (close to recovery time)
- Partial: Cycle overlap (cycles start stacking)
- Moderate: Cavity risk (attack time nearly doubles)
Cycles start stacking
New sugar arrives before pH fully recovers.
Overlapping acid cycles stretch total attack time sharply.
Shrinking recovery windows
Shorter gaps cut remineralization time short.
Cumulative acid exposure
Total daily attack time climbs steeply here.
Six-Plus Exposures, Near-Continuous Acid
Six or more exposures leave enamel almost no recovery.
- 7 / day: Exposures (near-continuous snacking)
- 35 min: Gap between hits (shorter than recovery)
- <10%: Recovery window (of waking hours)
- Severe: Cavity risk (chronic demineralization)
Near-continuous acid
Enamel barely rises above the critical threshold.
Six-plus exposures can erase recovery time entirely.
Chronic demineralization
Constant low pH outpaces natural mineral repair.
Highest cavity risk
Frequency alone now drives severe daily risk.
Same Sugar, Fewer Attack Cycles
Same total sugar, fewer exposures, far less attack time.
- 3 / day: Exposures (meals, not snacks)
- 200 min: Gap between hits (ample recovery time)
- Unchanged: Total sugar (same grams as stage 4)
- Low: Cavity risk (far less attack time)
Same sugar, fewer hits
Total sugar stays the same, exposures drop sharply.
Consolidating sugar into meals slashes daily attack time.
Longer gaps between meals
Wider spacing lets saliva fully buffer acid.
The frequency principle
How often beats how much for cavity risk.