“…Tetracyclines were introduced in 1948 as broad-spectrum antibiotics that may be used in the treatment of common infections in children and adults [25]. The use of low dose tetracycline as a histological bone marker has been well established since the 1960s with papers by Bevelander et al, [12], Ibsen and Urist [13], Faccini [14], Frost [15], and more recently by Ranggard [11], Engstrom [16], Sun et al, [17]. It was discovered that tetracycline is incorporated into hard tissues calcifying at the time of their administration and subsequently could be studied in undecalcified sections by fluorescence microscopy [12,14].…”