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Biomedical subjects

M P Filleul

Publications and source records attributed to M P Filleul.

8 recordsLinked to original sources

[Stability of orthodontic treatment of occlusal asymmetry].

A common finding in orthodontic patients is asymmetric occlusion. These asymmetries can be dental, skeletal, or functional in origin. Since many patients have typical posterior overjet the use of Class II-Class III and anterior crisscross elastics are contra-indicated. Even in skeletal discrepancies axial inclination compensation can produce relatively normal overjet in the arch. The best strategy for non-extraction therapy is to move teeth around the arch rather than an en-masse movement of the entire arch. A number of methods for unilateral distalization are discussed. Midline correction requires the determination of facial, apical base, and posterior midpoints. Differential mechanics between patients with apical base discrepancies and no apical base is presented. Although intermaxillary elastics can be indicated the undesirable effects of eruption and frontal occlusal plane tilt should be considered. Advantages in control and ease of occlusal correction rest with intra-arch mechanics. The use of intermaxillary elastics for the correction subdivision cases can lead to instability and or mandibular shifts.

Contraindications↗

Torsional properties of Ni-Ti and copper Ni-Ti wires: the effect of temperature on physical properties.

The stress-strain behaviour of two Ni-Ti and two Copper Ni-Ti orthodontic wires was examined in induced torsion under controlled conditions of moment and temperature. The tests clearly demonstrate the diversity of behaviour of these wires. The loading and unloading curves and plateau regions were found to be closely related to temperature with stiffness varying dramatically over mouth temperature range under identical stress. Diversity of reaction to stress is linked to the crystalline structure of the alloys.

Body Temperature↗

[A comparison of archwires of memory alloys Nitinol, NiTi Ormco and Tru-chrome which were subjected to edgewise torsion of 20 degrees, 25 degrees, 30 degrees and 35 degrees and a temperature of 37 degrees Celsius].

Nickel-titanium (Nitinol, NiTi Ormco) and stainless steel (Tru-chrome) orthodontic archwires were studied by means of torsion test at 37 degrees Celsius. At small activations (20 degrees, 25 degrees, 30 degrees) nickel-titanium wires have a comparable stiffness to stainless steel wires. At larges activations (from 35 degrees) nickel-titanium wires produce lower moments than stainless steel wires. At 35 degrees of activation the average stiffness of NiTi Ormco is 56% that of Tru-chrome. At 35 degrees of activation the average stiffness of Nitinol is 43% that of Tru-chrome.

Alloys↗