|Title of Invention||
FIVE SEGMENT ORTHODONTIC ARCHWIRE
|Abstract||The present invention relates to an arch wire that is used during orthodontic treatment. More particularly, the present invention relates to a continuous orthodontic arch wire with variable cross-sectional shape and size that is applied according to the anchorage requirement. It further relates to an orthodontic apparatus comprising such arch wire.|
|Full Text||FORM - 2
THE PATENTS ACT, 1970 (39 OF 1970)
(SEC - 10, RULE 13)
'AN IMPROVED ORTHODONTIC ARCH WIRE'
DR.VISHNU JAGDISHBHAI PATEL
An Indian National having addresss at D-304, SAMARPAN TOWER, NR. GHARDAGHAR, 132FT RING ROAD, NARANPURA, AHMEDABAD-380 013, GUJARAT STATE, INDIA.
The following specification particularly describes the invention:
The present invention relates to an arch wire that is used during orthodontic treatment. More particularly, the present invention relates to a continuous orthodontic arch wire with variable cross-sectional shape and size according to the anchorage requirement.
BACKGROUND OF THE INVENTION
Orthodontics is a specialized dental practice concerned with the movement of teeth to achieve an effective occlusion, and to provide a pleasing facial contour and appearance of the teeth. Canine retraction is an important biomechanical task in orthodontic treatment. A canine, being the corner stone of the dental arches needs to be placed in a position of stability to fulfill its role in functional occlusion. The biomechanics involved in canine retraction are either sliding mechanics or frictionless mechanics. Sliding mechanics is preferred over frictionless mechanics because of some disadvantages to frictionless mechanics using closing loop arch wires like, lot of time and skill required for tedious wire bending, limited range of action, requirement of extra tip and rotation control by putting extra bends and poor 3D control between anchor segment and retraction segment.
Mainly there are two type of bracket-wire configurations where the first one is conventional in which the arch wire is held with either ligature wire or elastic module and the other one is self -ligating bracket in which clip of the said bracket holds the wire in the bracket slots.
In conventional sliding mechanics, rectangular or circular or trapezoidal stainless steel wire of universal cross-sectional form (same cross-sectional shape and dimension through its entire length) is used. (16 x 22 in 018 slot & 19 x 25 in 022 slot).
For canine retraction 120-140 gm of force is required on either side; but additional 100-125 gm force is required to overcome frictional resistance for initiating tooth movement, so almost double force has to be applied for canine retraction. Accordingly double reactive force is felt on the anchorage unit according to Newton's 3rd low of motion.
Hence, the major drawbacks associated with the conventional arch wire used in canine retraction are:
1. It involves heavy force,
2. It can place considerable load on anchorage unit,
3. It can cause anchorage burn-out.
The best canine retraction suggested, in terms of duration, biologic health and anchorage preservation involves:
1. Optimal Force,
2. Minimum tissue damage,
3. Minimum or no anchorage loss.
Therefore, with the objective to fulfill above mentioned criteria and to obviate drawbacks of existing arch wires, the inventor has invented an improved orthodontic arch wire, which avoids sliding of arch wire through posterior anchorage unit brackets, and provide enough clearance for canine sliding with minimum possible frictional resistance. The advantages of the proposed invention are as below:
1. Better treatment result can be obtained as the anchorage is well maintained, so in high anchorage cases (majority of 1st premolar extraction cases), the extraction space is mostly utilized in canine retraction followed by four-incisor retraction.
2. Biological friendly forces are used, thus minimizing undermined hyalinization and undermined resorption.
3. Cost of overall treatment can be reduced as in majority of cases use of additional anchorage reinforcement with headgear, micro-
implants, mini-implants or 2nd molar bonding is reduced considerably and often used in critical situations only.
4. Duration of treatment is also reduced because of reduced frictional resistance and binding, so walking of canine on arch wire is faster than the conventional mechanics.
5. According to anchorage requirement, using various rounding edge radius and arch wire dimension combination, best possible clinical outcome can be achieved at comparable lower cost.
The present invention is directed toward orthodontic arch wires having an improved cross-sectional construction. The modified arch wire is a continuous wire with variable cross sectional shape and size as per following description.
The proposed arch wire comprises of following five sections:
1. Arch wire with rectangular cross-section, in posterior 2nd premolar and molar region in the left side of the jaw.
2. Arch wire with rounded off cross-section at all four corners, in the intermediate canine and 1st premolar region in the left side of the jaw.
3. Arch wire with rectangular cross-section in anterior incisor region.
4. Arch wire with rounded off cross-section at all four corners, in the intermediate canine and 1st premolar region in the right side of the jaw.
5. Arch wire with rectangular cross-section, in posterior 2nd premolar and molar region in the right side of the jaw.
In the intermediate canine and 1st premolar region, the corners of the wire are rounded off with varieties of radius value (r) where r2 =/ The radius r is selected according to anchorage requirement, rate of tooth movement, torque control and growth pattern.
[r2 =/ Frictional resistance is directly proportional to the surface area contact. By this modification, surface area contact is reduced considerably; thereby frictional resistance is also reduced. Thus the proposed arch wire provides significantly improved result than the conventional rectangular wire.
Baseline force, which is required to overcome frictional resistance when two objects slide over one-another, is approximately 36 gm [35 +/-5 gm] for orthodontic bracket slot and wire of similar material (Stainless steel).
There are mainly two standard slots with sizes 018 and 022 mil in which the arch wire is to be placed. Whenever larger dimension wire [17 x 22 mil and 17 x 25 mil in 018slot and 20 x 25 mil and 21 x 25 mil wire in 022slot] is used, first, the dimension of the wire at canine and 1st premolar region is reduced to the conventional one (up to 16 x 22 mil in 018 slot and 19 x 25 mil in 022 slot) for effective sliding then
it is rounded off. In critical situations, the same larger size wire is directly rounded off with respective radius in canine and 1st premolar region. Larger dimension wires are used only in extra critical anchorage situations. Thus by increasing arch wire dimension in anchor segment, wire sliding through anchor segment is reduced considerably, thus anchor loss is prevented. The said arch wire may be made up of stainless steel, super elastic nickel-titanium, tooth coloured teflon coated wire, Titanium Molybdenum Alloy (TMA or beta titanium) and similar.
Dated this 10th day of December 2007.
The Controller of Patents,
The Patent Office,
|Indian Patent Application Number||2468/MUM/2007|
|PG Journal Number||14/2014|
|Date of Filing||17-Dec-2007|
|Name of Patentee||DR.VISHNU JAGDISHBHAI PATEL|
|Applicant Address||D-304, SAMARPAN TOWER, NR.GHARDAGHAR, 132FT RING ROAD, NARANPURA, AHMEDABAD-380013,|
|PCT International Classification Number||A61C7/00|
|PCT International Application Number||N/A|
|PCT International Filing date|