(i) Enamel matrix derivative (EMD, for example, Emdogain[R], Straumann, Basel, Switzerland) is an extract of enamel matrix and contains amelogenins
, which are used to biomimetically stimulate the soft and hard tissues surrounding the teeth to regenerate following tissue destruction [16, 17].
The process of amelogenesis is a complex and regulated by ameloblasts that requires secretion of certain matrix proteins that includes amelogenins, amelins, enamelins and tuftelins and the previously formed dentine.3 Literature survey revealed that amelogenesis has three phases that are pre- secretory, secretory, and maturation.3
Considering the developmental stages of enamel formation of maxillary central incisors, it has been hypothesized that amoxicillin may interferes at secretory stages of amelogenesis or may reduce gene expression of matrix proteins (such as amelogenins) or decrease the activity of proteinases that hydrolyze matrix proteins.2 However, the exact molecular mechanism(s) of action is still unclear.
The matrix proteins are a heterogeneous group which are generally separated into amelogenins (major component) and enamelins.
To date, mutations in gene encoding the protein amelogenin have been shown to cause some X-linked recessive forms of AI.
Similarly, the amelogenins
, the principal proteins of the formative stage of tooth enamel, have been shown to form gels composed of agglomerative "nanospheres." These nanospheres have been observed in vivo with dimensions of 15 to 20 um (Fincham et al., 1994, 1995) and in vitro with dimensions that range to 100 nm and higher (Wen et al., 1999).
, its family of extracellular matrix proteins of the dental enamel, are transiently but abundantly expressed by ameloblasts during tooth development.
During the formation of dental enamel, ameloblasts secrete several enamel matrix proteins, including amelogenin
, ameloblastin and enamelin.
In addition, 1[alpha],25[(OH).sub.2][D.sub.3] was found to be able to regulate the expression of a tooth-specific gene: amelogenin
gene (Papagerakis et al.
(1994, 1995) of 15-20 nm "nanospheres" on the calcium phosphate surfaces of developing enamel have also been interpreted as proteinaceous, composed of amelogenin