Abstract: The present invention provides a evaluating system of masticatory efficiency comprising a first step of allowing a human subject to masticate an artificial food material containing microparticles that are finely crushed and ground by mastication and keep a spherical shape unless they are masticated; a second step of enlarging the artificial food material having been thus masticated by applying pressure to a thickness equal to the diameter of the microparticles while sandwiching the artificial food material between two preparation sheets; and a third step of counting microparticles keeping the spherical shape that remain in the artificial food material having been enlarged between the two preparation sheets by applying pressure. By using this evaluating system in the invention, the masticatory efficiency can be evaluated well in precise and at short time without using a solvent and expensive instruments.

Abstract: The present invention provides a evaluating system of masticatory efficiency comprising, a first step of allowing a human subject to masticate an artificial food material containing microparticles that are finely crushed and ground by mastication and keep a spherical shape unless they are masticated; a second step of enlarging the artificial food material having been thus masticated by applying pressure to a thickness equal to the diameter of the microparticles while sandwiching the artificial food material between two preparation sheets; and a third step of counting microparticles keeping the spherical shape that remain in the artificial food material having been enlarged between the two preparation sheets by applying pressure. By using this evaluating system in the invention, the masticatory efficiency can be evaluated well in precise and at short time without using a solvent and expensive instruments.

Abstract: An orthodontic bracket is provided for use with an arch wire. The bracket includes a bracket main member having upper, middle and lower portions. The middle portion includes a slot formed therein for receiving the arch wire. Wings are formed on the upper and lower portions of the bracket main member for enabling a ligature to be tied therewith to secure the arch wire in place in the slot. Engaging portions are formed on the wings for enabling the ligature to be held in a tied state on the wings such that the ligature avoids pressured contact with the arch wire, thereby allowing the bracket to move smoothly along the arch wire during orthodontic treatment requiring such movement.

Abstract: An orthodontic appliance having a pair of bases supported by guides so as to be capable of opening and closing. A memory alloy coil spring having superelastic properties is mounted between the pair of bases. The appliance is constructed so that the spring pressure of the superelastic memory alloy coil spring transmits to the tooth or the jaw bone as orthodontic force by means of the opening and closing of the pair of bases.

Abstract: A process for straightening teeth using super-elastic NiTi arch wires of the same diameter but having different recovery forces is carried out by using NiTi wires that have a transition temperature below body temperature with brackets on the teeth. The different recovery force is set for each wire by heat treating the wires at different temperatures and/or for different periods of time. In this manner the forces applied to the teeth can be changed while still using arch wires of the same diameter.

Abstract: A method of imparting a particular shape to a wire made of a shape memory alloy, such as a Ni-Ti alloy, which includes the steps of bending the wire inside a tubular body into the particular shape; heating the wire within the tubular body to a temperature sufficient to cause the wire to retain the particular shape; and removing the wire from the tubular body. The tubular body is made of a deformable metal, such as stainless steel or nickel-chrome alloy tubing, and includes a slit therethrough extending in its axial direction. The slit is provided to facilitate bending the tubular body and removing the wire from the tubular body.

Abstract: An orthodontic appliance has a bracket portion with an archwire slot formed therein. The archwire slot extends in the mesial-distal direction of the appliance and is dimensioned to receive an archwire. The orthodontic appliance has at least one pair of tie-wings. Each tie-wing projects outwardly from the bracket portion on an opposite side of the archwire slot with respect to the other tie-wing. One pair of opposing shoulders are located on the mesial end of the bracket portion, and another pair of opposing shoulders are located on the distal end of the bracket portion. Each shoulder is located on an opposite side of the archwire slot relative to the other shoulder of the pair. Each shoulder is adapted to support a ligature thereon, and is dimensioned and located with respect to the archwire slot, so that the ligature is spaced above an archwire received therein. The orthodontic appliance is therefore permitted to move relative to the archwire during orthodontic treatment.

Abstract: A continuous-length orthodontic coil spring is made from a shape-memory alloy wire wound into a coil. The coil defines a plurality of open coil sections defining spaces between the turns thereof, and closed coil sections formed between the open coil sections. The closed coil sections are tightly wound with insubstantial spacing between the turns thereof. The coil spring is made of a Ni-Ti alloy wire, and is heat treated to impart a predetermined range of spring force within a superelastic zone of deflection. The continuous-length coil spring is cut through the closed coil sections to form several shorter-length coil springs therefrom. The closed coil sections on either end of the shorter-length coil springs are thus adapted to engage the orthodontic brackets mounted to a patient's teeth, to accurately impart the force of the spring to the brackets.

Abstract: An orthodontic shape-memory alloy archwire for ligating to orthodontic appliances is heat treated, so that different sections of the archwire each exhibit a predetermined modulus of elasticity, and therefore impart a predetermined range of force when deflected. The distal ends of the archwire are further heat treated, or are treated with a dopant, to exhibit substantially diminished superelastic properties in comparison to the other sections of the archwire. The distal ends can therefore be deformed into shapes when ligated to orthodontic appliances to secure them to the appliances, and thus prevent them from slipping therethrough.