Tooth eruption: a 'neuromuscular theory'. part two

Background/Objective: Tooth eruption is a foundational subject for every dental practitioner as well as dental students; and literature is replete with different mechanisms of migration of a tooth from its bony crypt into the oral cavity. The purpose of the part two of this study was to evaluate and test the proposed “neuromuscular theory of tooth eruption” using relevant scientific papers, as supporting bodies of evidence, to unify the currently accepted mechanisms of tooth eruption under single theory. Materials and Methods: A detailed and systematic analysis, synthesis and integration of the findings from relevant scientific studies (selected according to specific inclusion and exclusion criteria) on mechanisms of tooth eruption was conducted as it was done with part one of this study. Results: The propelling force of tooth eruption is attributed to piezoelectricity, mechanosensation, mechanotransduction, mechanical pull on the hydroxyapatite crystals; mechano-hydrodynamic force; and mechanics of the mandible and the orofacial muscles with attendant biochemical, electrical, electrochemical, cellular, molecular and enzymic activities to prepare the jaws and other facial bones for coronal migration of a developing tooth from its bony crypt until it emerges in the oral cavity. Conclusion: “Neuromuscular theory of tooth eruption” is based on neuromuscular forces, arising from muscular contractions in the orofacial region. Mechanosensation, mechanotransduction and piezoelectricity are the three principal processes of converting neuromuscular forces into electrical, electrochemical and biochemical energies for initiation and sustenance of cellular, molecular and enzymic activities during the different phases of tooth eruption process. The clinical relevance of this theory is that it throws more light on the morphological and functional interdependence of the various elements of the maxillo-mandibulo-dental system as well as the need for neuromuscular considerations in the diagnosis, treatment planning, prevention and treatment of pathological conditions of tooth eruption. Key words: Mechanosensation, Mechanotransduction, Neuromuscular, Theory, Tooth eruption.