THE PROPERTIES OF THE THE PROPERTIES OF THE ORTHODONTIC ARCHESORTHODONTIC ARCHES

OUTLINEOUTLINE• FlexibilityCross sectionLengthMaterial properties• FrictionImportance of the ligaturesMaterial propertiesCross section importance

Stiffness and the cross-sectional Stiffness and the cross-sectional dimensiondimension

of the wiresof the wires• The form of cross

section• The variation of cross

section size

Stiffness and the lengthStiffness and the lengthof the wiresof the wires

• The connection between the length of the wire and the inter bracket distance

loop

The possibility of the enlarge of The possibility of the enlarge of the lengththe length of wiresof wires

Loop systems

• Upper retractor• Lower retractor• Delta loop

Utility and the sectional arch

Stiffness and the materialStiffness and the materialof the wiresof the wires

• Gold alloy• Iron alloy• Titan alloy

Three-point bending test

• L=10mm• Bending 5mm

Gold alloy

• Nowadays uses only as a coat material

• A TMA wires stiffness similar with the gold arches

Iron alloy

• Iron with Chrome-nickel• Iron with Cobalt-chrome-nickel

Cobalt-Chrome-nickel-ironElgiloy

• Material: Cobalt(40%) Chrome(20%) Nickel(0,15%), Molibden(7%),

Manganese(2%), Beryllium(0,04%) Carbon(15%), Iron(15,81%)

• Annealing

Titan alloy

• in the martensitic form stabilised titan alloy

• in the austenitic form stabilised titan alloy

• Super elastic alloycu NiTi

Austenitic form stabilised titan alloy

• titan molybdenum wire

TMA arch (beta-titanium)

In the martensitic form stabilised titan alloy

• titan- nickel- cobalt Nitinol or M niti

Super elastic alloyA-NiTi

• 1985 Chinese NiTi• 1986 Japanese NiTi Sentalloy Fujio Miura• 1988 DREHT method

Nivelliation with super NiTi- wire

10 mm10 mm

10 mm10 mm

16x22 superelastic 118cN

(16x22 iron 1360cN)

16x22 superelastic 63cN(16x22 iron 730cN)

Super-NiTi arch, force-deflection diagram

Super elastic arches force-deflection curves

The DREHT method arches properties

The influence of the frictionThe influence of the friction• Ligation• Diameter of the arch• Material of the arch • Surface of the

elements• System without

friction

The ligation forms

• Traditional ligature wire• Elastic ligatures different

forms

Special brackets for ligation

Newest techniques in the ligation