WO2015054726A1

WO2015054726A1 - Orthodontic device and method

Info

Publication number: WO2015054726A1
Application number: PCT/AU2014/000973
Authority: WO
Inventors: Morris RAPAPORT
Original assignee: Rapaport Morris
Priority date: 2013-10-15
Filing date: 2014-10-15
Publication date: 2015-04-23

Abstract

A new dental appliance incorporates mandibular advancement blocks into upper and lower sequential plastic aligners, enabling simultaneous treatment of both crooked teeth and an undershot jaw. Because the alignment of teeth can proceed together with the correction of the jaw relationship and upper dental protrusion, this approach is far more efficient than a sequential treatment approach of first correcting jaw alignment with mandibular advancement and then afterwards, straightening the teeth with sequential plastic aligners.

Description

ORTHODONTIC DEVICE and METHOD

This invention relates to a method of enabling simultaneous tooth alignment and correction of Class II malocclusion. Background to the invention

Many appliances have been devised to correct teeth alignment and jaw

relationships. Braces to straighten teeth have been used for a long time and appliances to correct jaw alignments have been proposed for use with children and teenagers where growth is continuing.

USA patents 6027340 and 7730891 are concerned with devices for correcting the position of the jaw.

USA patent 4433956 discloses an expandable appliance that is periodically adjusted.

USA patent 7001180 corrects malocclusions and prevents snoring.

All of these address the problem of jaw position only.

Currently, sequential plastic aligners (such as Invisalign) are mainly used for straightening teeth, and functional appliances, such as Clark Twin Blocks, are used to improve jaw relationships in Class II malocllusion.

A computer aided program of using successive plastic aligners to straighten teeth, is the subject of many patents including USA 5975893, 7134874 and Australian patent 2005227885. USA patent 7957824 explains techniques for bulk manufacture of aligners of this type.

Currently practitioners carry out these treatment programs separately usually correcting the jaw relationship first and then straightening the teeth. These treatment programs usually take upward of 6 months each. This time period has a significant impact on the lives of the patients who are usually teenagers.

It is an object of this invention to ameliorate this problem.

Brief description of the invention

To this end the present invention provides a dental appliance for correcting jaw relationships and straightening teeth at the same time which consists of an integral appliance for each of the lower and upper set of teeth said appliance for the lower set of teeth incorporating an aligner fitting over the lower teeth said aligner having a mandibular advancement block projecting above the rear teeth on each side and the appliance for the upper teeth consists of an aligner fitting over the upper teeth said aligner having a mandibular advancement block projecting below the rear teeth on each side to engage the blocks on the appliance for the lower set of teeth.

This invention is partly predicated on the insight that two procedures normally conducted sequentially can be combined. This method incorporates mandibular advancement blocks into upper and lower sequential plastic aligners, enabling simultaneous treatment of both crooked teeth and an undershot jaw. Because the alignment of teeth can proceed together with the correction of the jaw relationship and upper dental protrusion, this approach is far more efficient than a sequential treatment approach of first correcting jaw alignment with mandibular advancement and then afterwards, straightening the teeth with sequential plastic aligners. Four blocks, one in each dental quadrant in the bicuspid molar region, are incorporated into the plastic aligners. The blocks can be bonded onto the aligners or incorporated during the aligner manufacturing process. The blocks have matching inclined planes so that they have the effect of holding the lower jaw open and forward. The blocks are made so as to have an opening of approximately 3mm between the front central incisor teeth and a protrusion with the front teeth edge-to-edge. The aim is for the jaw to be sufficiently open beyond the freeway space to ensure that the lower jaw cannot slip back but must stay forward because the lower block engages the upper inclined plane.

The ability to carry out the two procedures in parallel rather than sequentially is of greatest benefit to the patient who is usually a teenager and a time saving of the order of four months is psychologically significant. The improved efficiency also reduces the number of visits required to the Dental professional providing a cost saving as well.

Detailed description of the invention.

A preferred embodiment of the invention will now be described with reference to the drawings in which

figure 1 is a schematic illustration of this invention;

Figure 2 is a representation of a device according to this invention for use on the lower teeth; Figure 3 is a representation of a device according to this invention for use on the upper teeth;

As seen in figure 1 the teeth alignment devices 10 and 20 are integrally moulded with the jaw adjustment blocks 13 and 23. The lower set comprises the teeth alignment appliance 10 which fits over the lower teeth and integrally moulded with this are the lower adjustment blocks 13 having a rear inclined face 15. The upper set comprises the teeth alignment appliance 20 which fits over the upper teeth and integrally moulded with this are the upper adjustment blocks 23 having a forward inclined face 25. The sides of the blocks 13 and 23 parallel to the teeth line extend down to thicken the plastic aligner coverage of the teeth and this improves the stability and robustness of the blocks. It is possible to form the blocks separately and adhere them to the aligners at the appropriate positions.

The blocks 13 and 23 are preferably made from the same polymeric material as the aligners and may be made by the same computer aided manufacturing process, method. The blocks may be reinforced with same material or other suitable material without compromising the performance of the appliance. Other suitable materials may be polycarbonate or polyacrylates including grades of polymethylmethacrylate. The method may be by thermoforming from suitable sheets of dental thermoforming polymeric material. Other suitable methods may be by casting or injection moulding. Advanced manufacturing techniques such as Stereolithography, 3D printing, Laminate object manufacturing, fused deposition modelling and laser machining may be used to form molds for the aligners.

The inclined planes of the faces 15 and 25 slope at approximately 70 degrees to the occlusal plane and are located in the second bicuspid region. The occlusal surface of the blocks is parallel with the occlusal plane and the blocks are sufficiently hard to withstand biting forces. Sufficient tooth coloured composite attachments on the teeth provide additional retention for the appliances.

The blocks are incorporated into the aligners approximately five months after commencing sequential plastic aligner treatment. By then, some anterior bite opening, levelling and alignment of teeth has occurred.

The usual bite recordal techniques are used to record the preferred position of the jaws when the front teeth are in a preferred relationship. The impression is the used to devise the appropriate block sizes. The blocks are then incorporated into the plastic aligners that are prescribed for the next four months.

Directly following this treatment phase, sequential plastic aligners continue, and in addition, Class II elastics are attached to elastic hooks cut into the aligners to maintain the correction. The elastics are stretched from the front at the top to the bottom at the back on the cheek sides and can continue the Class II correction. This reduces the usual length of jaw orthopaedic treatment because the elastics take over and the aligners keep the teeth discluded, thereby assisting the Class II correction.

Sequential plastic aligner treatment with incorporated bite blocks is possible at all ages but is mainly indicated while growth is occurring. It can be used in treating Class II division 1 or Class II division 2 cases because the initial aligners used in the first five months prior to incorporating the blocks can procline the upper central incisor teeth. This converts the Class II division 2 case into a Class II division 1. Not only is the simultaneous correction of teeth as well as jaw alignment more time efficient, it also saves the cost of an extra pair of oral appliances while adding only a smaller cost for the blocks. Therefore, the great advantage of incorporating jaw advancement blocks into sequential plastic aligners is treatment efficiency - because of time saving - as well as cost saving.

Those skilled in the art will appreciate that this invention provides an appliance that is easy to use and provides time saving benefits to the patient.

Those skilled in the art will also realise that this invention may be implemented in embodiments other than those described without departing from the core teachings of this invention.

Claims

1. A dental appliance for correcting jaw relationships and straightening teeth at the same time which consists of an integral appliance for each of the lower and upper set of teeth said appliance for the lower set of teeth incorporating an aligner fitting over the lower teeth said aligner having a mandibular advancement block projecting above the rear teeth on each side and the appliance for the upper teeth consists of an aligner fitting over the upper teeth said aligner having a mandibular advancement block projecting below the rear teeth on each side to engage the blocks on the appliance for the lower set of teeth.

2. A dental appliance as claimed in claim 1 wherein the blocks and the aligners are made from the same material.

3. A method of treating tooth alignment and correction of Class II malocclusion wherein the dental appliance as claimed in claim 1 is used.

4. A method as claimed in claim 3 in which the use of the appliance as claimed in claim 1 commences after the teeth straightening treatment has

commenced.