The Topical Effect of Two Artificial Baby Milk Formulas on Enamel of Primary Teeth: An In Vitro Study

Objective: This in vitro study aimed to investigate the topical effect of two artificial baby milk formulas on the enamel of primary teeth by measuring both the enamel surface microhardness and mineral content. Materials and Methods: A total of 14 human primary molars were selected and divided into two equal main groups (n=7) according to the used baby milk formula; Group (1): 7 teeth for NAN Optipro 2, and Group (2): 7 teeth for Primalac Ultima 2. All crowns were bisected mesiodistally into two halves buccal and lingual where each main group was subdivided into two equal subgroups (n=7); Control group: 7 molar halves without milk soaking, and Experimental group: 7 molar halves with soaking in the corresponding milk formula. Each molar half was mounted individually and centrally in acrylic resin block. The enamel surface work area was etched using 37% phosphoric acid etching gel for 90 seconds followed by storage in artificial saliva for 3 hours. Enamel surface microhardness was evaluated using calibrated Vickers hardness machine, while measurement of mineral content was made using SEM- EDX. Resulted data were statistically analyzed at p-value ≤ 0.05. Results: The enamel surface microhardness slightly increased after soaking specimens in both tested milk formulas with no statistically significant differences. Regarding mineral content, soaking specimens in both milk formulas resulted in higher concentration of all measured elements (P, Cl, Ca) except (O); however, none of these changes reached statistical significance. Conclusions: The short-term topical exposure of primary enamel to both artificial baby milk formulas tested produced enamel surface with slightly improved microhardness profile. In addition, both formulas showed a comparable, limited, and overall positive impact on the primary enamel mineral composition.