Spectroscopic examination of enamel staining by coffee indicates dentin erosion by sequestration of elements

Sinai H.C. Manno, Francis A.M. Manno, Irfan Ahmed, Rafay Ahmed, Lei Shu, Li Li, Shisan Xu, Fangjing Xie, Vincent Wai Li, Johnny Ho, Shuk Han Cheng, Condon Lau

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


The mechanism of coffee eliciting erosion on teeth is unclear as few studies have investigated the direct effect of coffee on enamel and dentin structures. The present study identified how coffee, the most popular beverage worldwide, induces staining and erosion on teeth. We show the grade of erosion of molars and incisors in Sprague Dawley rats from two different age groups, young (four weeks) and old (six months). We quantified the concentration of metals contained in coffee by mass spectrometry (ICP-MS). To determine elemental content in enamel (i.e. superficial) and dentin (i.e. substructure), we used Laser-induced Breakdown Spectroscopy (LIBS) and X-ray fluorescence (XRF) spectroscopy, respectively. For LIBS, a significant decrease of Ca, P, and Na was observed in the young coffee group relative to age-matched controls, whereas a significant increase in Mn, Fe, and K was observed. In the old coffee group, a significant increase of Mg, Fe, and K was observed along with a decrease of Mg, Ca, P, Na, Sr and Zn. For XRF, a significant decrease of the Ca/P ratio in the coffee group was observed. Spectroscopy results were correlated with scanning electron microscopy (SEM) and histological analysis. The SEM analysis showed pores and open spaces between young and old coffee groups, respectively. Thinning of enamel layers, loss of continuity in the enamel-dentin-junction, and wide spaces in dentin tubules with coffee use was found histologically. Coffee induces decalcification of teeth that corresponds to erosion, exposing the dentin structure by reducing enamel. Coffee immersion demonstrated an intrinsic staining in dentin by metal deposition.

Original languageEnglish
Pages (from-to)550-559
Number of pages10
Publication statusPublished - Nov 1 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry


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