The effects of third-order torque and self - Saint Louis University

ehavior of saliva depended on the material composition of
the slots and wires. For example, when saliva was
introduced in stainless steel slots, it produced decreases
in frictional resistance with ß-titanium alloy wires, but
an adhesive effect with stainless steel wires.
Occlusal Forces
In the human dentition, the deformable periodontal
ligament allows minute movements of the teeth to aid in
distribution of forces from occlusal function. These
forces, that can arise as a result of speaking, swallowing,
or normal masticatory function, are heavy (1 kg to 50 kg)
and intermittent, occurring thousands of times per day for
one second or less. 8,88 These brief movements of the teeth
alter the normal forces between the crown-attachment slot
and wire, constantly breaking and resetting “friction
locks.” 5 Studies have been conducted to determine the
effect of perturbations (extraneous, small actions
simulating mastication, swallowing) on frictional forces in
the orthodontic appliance. Braun’s group, 88 with an in
vitro model, found a reduction in sliding resistance
proportional to the magnitude of extraneous forces. Using
a half-arch model, Lingenbrink 89 found an average decrease
in kinetic frictional forces of 49% when perturbations were
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