TABLE 4.

Prevalence of fluorosis on maxillary incisors (two or more teeth of four versus none) according to fluoride source: upper quartiles versus lower three quartiles.

INTAKE GROUP*	FLUORIDE INTAKE SOURCE†			NO. OF PARTICIPANTS	PERCENTAGE PREVALENCE OF FLUOROSIS	RELATIVE RISK (95% CI§)	COMMON RELATIVE RISK¶ (95% CI)
	Ingested dentifrice (16–36 months)	Other beverages with added water‡ (3–9 months)	Powdered formula (3–9 months)
1A	Low/moderate	Low/moderate	Low/moderate	203	20.7	1.68 (1.11, 2.54)	1.40 (1.06,1.84)
1B	Low/moderate	Low/moderate	High	72	34.7
2A	Low/moderate	High	Low/moderate	67	38.8	1.01 (0.58, 1.75)
2B	Low/moderate	High	High	28	39.3
3A	High	Low/moderate	Low/moderate	82	35.4	1.62 (0.94, 2.77)
3B	High	Low/moderate	High	14	57.1
4A	High	High	Low/moderate	17	35.3	0.94 (0.31, 2.91)
4B	High	High	High	9	33.3

^*Stratified according to intake of fluoride from powdered formula, dentifrice and other beverages with added water.

^†All fluoride intake sources are grouped by area-under-the-curve intake quartiles.

^‡Includes nonformula beverages made from frozen concentrate or powder.

^§CI: Confidence interval.

^¶Mantel-Haenszel relative risk. Result of the Breslow-Day test for homogeneity of odds ratios was not significant (P = .48). General association P value was .02.