Metal braces are still the gold standard in orthodontic treatment and the most common type. That doesn’t mean they haven’t advanced over the years. The earliest written documentation on use of metal appliances to straighten teeth was by Pierre Fauchard way back in the 1700’s. Formerly, bands were used which completely encircled the tooth. This was the era of “metal mouth” or “railroad tracks”. Today, a small bracket is bonded to the front of the tooth. Enamel is the hardest part of the body so an intricate process is required to adhere the bracket to the tooth. First the tooth surface is cleaned, and then a mild acid is applied to chemically roughen the surface. A primer layer is applied to this matte finish and an adhesive is sandwiched between the bracket base and the tooth. The bracket base has a mesh design to lock onto the adhesive. Dr. Bentele will look through magnifying loupes for precise positioning of the bracket. The final step uses an LED to cure the light sensitive adhesive to fix it into position.
An orthodontic bracket is a mini engineering masterpiece and is individualized for each particular tooth in the arch. On the front of the brackets are 4 tie wings to attach the wire with multicolored O-rings or metal ligature. A slot for the wire runs across the face of the bracket. Designed into that bracket slot are the instructions for positioning the tooth including how prominent that tooth is in the arch, the tip of the crown and how much the crown angles outwards. The orthodontic wires use the bracket as a handle to transfer force to the tooth root and thence to the bone. Orthodontics works by remodeling the surrounding bone. The orthodontist decides what composition of wire type, wire size and force is best suited to move a tooth a certain way. A force on the tooth root either puts pressure or tension on the periodontal ligament (PDL) which is in between the tooth root and bone. Cells then are recruited in to do the remodeling work. Osteoclasts remove bone on the compression side and osteoblasts create it on the tension side as the tooth is repositioned. If too much force is applied in an effort to speed up the orthodontics then the tooth root rather than the bone may be resorbed or a scar may be formed in the PDL that has to heal before further movement can occur. Patience is a virtue.