Advanced Orthodontic Retainer

Abstract

An advanced thermoplastic orthodontic retainer is disclosed. The prior art includes a clear piece of thermoplastic material of uniform thickness which is then heated to a soft state and adapted to a stone model of a patient's teeth. The present invention incorporates a gradient of thickness of the plastic running from one end to the other. This gradient will exist in the final retainer, and it will take into account the normal pattern of opening and closing of the jaw during which the posterior segment is open less than the anterior segment when the teeth are close to contacting. The present invention retains the ease of fabrication, low cost, and aesthetics of the currently prescribed removable appliance while improving the durability and functionality. Dentists and orthodontists can use the present invention to prevent the unwanted side effects of the prior art including but not limited to posterior open-bites.

Claims

1. A method of fabricating a removable dental retention and alignment devices comprising: a. Providing a thermoplastic sheet, wherein the thermoplastic sheet i. has a first end and a second end; ii. the first end has a first thickness; iii. the second end has a second thickness; iv. the sheet of thermoplastic material has a gradient of thickness between the first end and the second end. b. heating the sheet to a soft state; c. adapting the sheet to a model of a set of teeth of a dental patient while the sheet is heated; d. allowing the sheet to cool.

2. The method of claim 1, wherein the model is a stone model.

3. The method of claim 1, wherein the gradient of thickness is uniform.

4. The method of claim 1, wherein the gradient of thickness is non-uniform.

5. The method of claim 1, further comprising a visible indicator of the direction of the gradient of thickness.

6. The method of claim 1, wherein the sheet of thermoplastic material comprises a square with sides measuring 120 millimeters.

7. The method of claim 1, wherein the sheet of thermoplastic material comprises a square with sides measuring 125 millimeters.

8. The method of claim 1, wherein the first end has a thickness of selected from the group consisting of 0.5 millimeters, 0.75 millimeters, 1.0 millimeters, 1.5 millimeters, 2.0 millimeters, and 3.0 millimeters, 4.0 millimeters, and 5.0 millimeters.

9. The method of claim 1, wherein the sheet is circular.

10. The method of claim 1, wherein the sheet is rectangular.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 shows a top view of the thermoplastic sheet of the prior art

[0015] FIG. 2 shows a perspective view of a thermoplastic sheet of the prior art.

[0016] FIG. 3 shows a perspective view of an embodiment of the present invention wherein the thermoplastic sheet is rectangular and the gradient is uniform.

[0017] FIG. 4 shows a perspective view of an embodiment of the present invention wherein the thermoplastic sheet is circular and the gradient is uniform.

[0018] FIG. 5 shows a perspective view of an embodiment of the present invention wherein the thermoplastic sheet is rectangular and the gradient is non-uniform.

[0019] FIG. 6 shows a perspective view of an embodiment of the present invention wherein the thermoplastic sheet is circular and the gradient is non-uniform.

DETAILED DESCRIPTION OF THE INVENTION

[0020] In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings, which form a part of this application. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

[0021] The following is a listing of the reference numbers included in the original drawings and the element that each reference number corresponds to and a brief description:

[0022] 1. A sheet of thermoplastic material

[0023] 2. A thickness of the sheet of thermoplastic material.

[0024] 3. A first end of the sheet of thermoplastic material

[0025] 4. A second end of the sheet of thermoplastic

[0026] 5. A gradient of thickness between the first end 3 and second end 4.

[0027] 6. A visible indicator of the direction of the gradient of thickness.

[0028] 7. A thickness of the first end 3 of the sheet of thermoplastic material 1.

[0029] 8. A thickness of the second end 4 of the sheet of thermoplastic material 1.

[0030] The present invention includes a thermoplastic sheet 1 adapted for use in fabricating a removable dental retention and alignment device comprising a sheet of thermoplastic material having a thickness 2, wherein the thickness 2 of the thermoplastic sheet 1 is non-uniform. The sheet of thermoplastic material has a first end 3 and a second end 4; the first end has a first thickness 7; the second end 4 has a second thickness 8; the sheet of thermoplastic material has a gradient of thickness 5 between the first end and the second end. The thermoplastic sheet may also have a uniform gradient of thickness. The thermoplastic may also have a non-uniform thickness. The invention may optionally include a visible indicator 6 of the direction of the gradient of thickness.

[0031] The thermoplastic sheet may optionally comprise a square with sides measuring 120 or 125 millimeters 8. The thermoplastic sheet may have a first end with a thickness selected from the group consisting of 0.5 millimeters, 0.75 millimeters, 1.0 millimeters, 1.5 millimeters, 2.0 millimeters, and 3.0 millimeters, 4.0 millimeters, and 5.0 millimeters. The above quoted sizes are usable for the most commonly available vacuum form retainer fabrication machines. The sheet may also be circular. An another embodiment of the present invention comprises a method of fabricating a removable dental retention and alignment device comprising providing a thermoplastic sheet 1, wherein the thermoplastic sheet 1 has a first end 3 and a second end 4; the first end 3 has a first thickness 7; the second end 4 has a second thickness 8; the sheet of thermoplastic material has a gradient of thickness between the first end and the second end; heating the sheet to a soft state; optionally adapting the sheet to a stone model or other type of model of a set of teeth of a dental patient while the sheet is heated; then allowing the sheet to cool. [0032] Use of the Orthodontic Retainer of the Present Invention

[0033] Fabricating the appliance with the thicker end towards the posterior teeth will result in a retainer for open bite tendency patients. The thicker plastic between the posterior teeth with act as a bite block creating several millimeters of jaws separation just as acrylic retainers do. Except this retainer will cost much less and be much easier to fabricate than said acrylic retainer.

[0034] Fabricating the appliance with the thicker end towards the anterior, thick enough to disclude the posterior teeth result in a retainer for deep bite patients. The thicker plastic between the anterior teeth will help maintain the bite opening achieved during treatment by creating several millimeters of jaw separation just as retainers with an anterior bite plate do. This will facilitate the eruption of the posterior teeth and maintenance of the vertical position of the anterior teeth.

[0035] Fabricating the appliance with a resulting gradient which closely matches the natural gradient of bite opening will result in a retainer with no unequal distribution of occlusal force between the anterior and posterior teeth. In ideally finished cases, this will reduce the tendency for posterior open bites occurring due to excessive posterior occlusal forces on the retainer. This will distribute the forces of the occlusion more evenly and reduce wear and the tendency for the retainer to break. When the majority of the force is on posterior teeth as is the case with the current design, the retainer tends to flex as the teeth bite down, causing excess wear and a tendency for the retainer to break.

[0036] During normal closure the mandible follows a pathway determined by the individual's musculoskeletal matrix. The majority of the occlusal forces during closure and mastication fall on the posterior teeth, those teeth that are adapted for those forces. The anterior teeth are normally designated for making initial cuts into food otherwise known as incising the food.

[0037] Now Applicant would like to discuss an example Applicant is familiar with in his orthodontic practice of the shortcomings of the prior art. A patient who has been wearing a 0.040 clear thermoplastic suck-down retainer for approximately 22 hours per day for over 3 months was examined. The teeth were dried and the patient was asked to bite directly down on occlusion indicating paper on all areas of his occlusion prior to the occlusal photos. The red and blue marks indicate occlusal contacts, larger marks indicating heavier occlusal contacts. This patient has no contact of his posterior teeth.

[0038] The loss of contact of posterior teeth is a common side effect of Essix retainer wear. This is due to the natural jaw position and the tendency for the jaw to want to return to its baseline mandibular plane angle or rest position. Because the jaw wants to rest with unequal space between the anterior and posterior teeth, the thickness of the Essix plastic in the posterior region causes intrusion of the posterior teeth. Thus, there is loss of occlusal contact.

[0039] This illustrates the problems associated with prescription of the currently used suck-down retainer. Contact of the upper and lower teeth is only occurring on the anterior teeth. Yet we know the posterior teeth are more suited for the occlusal forces of mastication.

[0040] Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the embodiments of this invention. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents rather than by the examples given.