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The orthodontic supply market is a prosperous billion-dollar industry, driven by an increasing demand for orthodontic appliances. The supremacy of metallic first-generation biomaterials is evident for manufacturing brackets, archwires, bands, and other components due to their well-recognized chemical inertness, spontaneous passivation, biocompatibility, and favorable mechanical properties combination. However, the oral cavity is the ultimate corrosion-promoting environment for any metallic material.
“branch of dentistry that is concerned with the supervision, guidance and correction of the growing and mature dentofacial structures. It includes the diagnosis, prevention, interception and treatment of all forms of malocclusion of the teeth and associated alterations in their surrounding structures”.[1]
Main Composition | Young’s Modulus (GPa) | Yield Strength (MPa) | |
---|---|---|---|
Human molar tooth enamel | Calcium phosphate hydroxyapatite | 70–115 | |
Stainless steel (AISI 316L) |
Fe–Cr–Ni | 160–187 | 960–1500 |
Cobalt–chromium | Co–Cr–Fe–Ni | 150–217 | 830–1200 |
α-Titanium | Ti (grade 4) | 104 | 550 |
β-Titanium | Ti–Mo–Sn–Zr | 60–68 | 620–690 |
Ti-6Al-4V | Ti–Al–V (grade 5) | 100–110 | 830–1070 |
Nickel–titanium | Ni–Ti | 32–36 | 200–500 |
Function | Description | Agents |
---|---|---|
Tissue lubrication, repairing, and protection | Seromucous covering of the oral tissues. Barrier against irritants. Lubrication of hard and soft tissues, and prosthesis. Mastication, speech, and deglutition aid due to lubrication. Selective modulation of microbial adhesion to oral tissues. Modulation of dental plaque metabolism. Faster tissue repair. |
Mucins and other proteins. |
Clearance and pH maintenance | Acids neutralization (e.g., bicarbonate buffer). Alkalinization of dental plaque’s pH through urea metabolization by its microbiome. pH modulation to prevent reaching optimal conditions for oral colonization by pathogens. |
Bicarbonate, phosphate, urea, amphoteric proteins, and enzymes. |
Maintenance of dental integrity | Modulation of pathogens activity to control the progression of caries and enamel damage. Maintenance of the enamel mineralization/demineralization equilibrium. The presence of fluoride in saliva enhances mineralization and forms a fluorapatite-like coating, which is more resistant to caries than the original teeth material. |
Calcium, phosphate, fluoride, and several proteins (including statherin, histatins, cystatins, and proline-rich proteins). |
Antibacterial activity | Selective action of protein-based immunological and non-immunological agents, allowing the growth of non-cariogenic microorganisms. Among other mechanisms, the non-immunological action involves the adhesion inhibition of colonizers to the oral tissues, namely by aggregation (clumping). |
Immunoglobulins, enzymes, and other proteins (including glycoproteins, staherins, agglutinins, histidine-rich proteins, and proline-rich proteins). |
Digestion, taste, and smell | Besides lubricating food and tissues, saliva starts the chemical oral digestion, namely by the initial action of the α-amylase (converting complex carbohydrates into simple sugars). The hypotonicity of saliva (low sodium, glycose, bicarbonate, and urea levels) regarding plasma, which enhances the dissolution of the substances. The presence of proteins (such as gustin) is necessary to the growth of gustatory buds. |
α-amylase, gustin, lipases and other proteins. |