Inventor : Tim Glowik

Applicant :

Bixby International Corporation Newburyport, MA

US

STATEMENT REGARDING GOVERNMENT INTEREST

Not applicable .

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit from U . S . Provisional Patent Application Serial No . 63/373, 434, filed August 24, 2022, which is incorporated by reference in its entirety .

BACKGROUND OF THE INVENTION

The present invention generally relates to dental aligners, and in particular, to preheating and thermoforming polysulfone film into dental aligners . Like traditional braces, dental aligners are designed to move teeth a little at a time . The aligners are plastic replicas of one' s teeth . Wearing them puts gentle pressure on the teeth, ever-so-slightly repositioning them . Dental aligners can be clear or not clear . Clear aligners are one of many technological advancements that have made orthodontic treatment less conspicuous, and one of many appliances orthodontists use to move teeth and align jaws .

Dental aligners, as they are shaped using sheets of films, have a tendency to absorb water from the air and change their form . This changed form affects the functionality of these dental aligners . There is thus a need for a process which helps minimize the moisture accumulation in these dental aligners as they are formed .

SUMMARY OF THE INVENTION

The following presents a simplified summary of the innovation in order to provide a basic understanding of some aspects of the invention . This summary is not an extensive overview of the invention . It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention . Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later .

In an aspect, the invention features a method including preheating a stock film of polysulfone(PSU) , polyphenylsulfone (PPSF or PPSU) or polyether sulfone (PES) in an oven at a temperature of 350°F to 450°F for 30 to 200 seconds to generate a moisture-free film, the stock film in a form of a roll, a sheet, or a disc, cutting the moisture- free film into pieces, and subjecting each of the moisture-free film pieces to a thermoforming process to produce a dental aligner .

These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings . It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed .

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described in detail with reference to the accompanying drawings, wherein :

FIG . 1 illustrates an exemplary dental aligner made using a nonpreheated film of polysulfone(PSU), polyphenylsulfone (PPSF or PPSU) or polyether sulfone (PES) .

FIG . 2 illustrates an exemplary dental aligner made using a preheated film of polysulfone(PSU) , polyphenylsulfone (PPSF or PPSU) or polyether sulfone (PES) .

DETAILED DESCRIPTION OF THE INVENTION

The subject innovation is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout . In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention . It may be evident, however, that the present invention may be practiced without these specific details . In other instances, well- known structures and devices are shown in block diagram form in order to facilitate describing the present invention .

As used herein, the term "dental aligner" refers to a plastic orthodontic appliance that is shaped to fit over one ' s teeth and is used to correct or adj ust the alignment of one ' s teeth . Dental aligners can be made of a variety of plastic material and the material can be opaque, transparent, semi- transparent, non transparent, or a combination thereof .

As used herein, polysulfone( PSU ) refers to any of a class of resinous organic chemical compounds belonging to the family of polymers in which the main structural chain most commonly includes benzene rings linked together by sulfonyl (-S0 ₂ -) , ether (-0-) , and isopropylidene (-C( CH ₃ ) ₂ -) groups .

PSU is a high temperature, amber colored, semi- transparent plastic material with good mechanical properties . Polysulfone is resistant to degradation from hot water and steam and it is often used in medical and food preparation applications where repeated sterilization is required .

As used herein, polyphenylsulfone ( PPSF or PPSU ) refers to a high performance polymer made of aromatic rings linked by sulfone (S0 ₂ ) groups . PPSF is a moldable plastic often used in rapid prototyping and rapid manufacturing ( direct digital manufacturing ) applications . As used herein, polyether sulfone (PES) refers to a transparent, high-performance polymer known for its dimensional stability at high temperatures in both air and water .

The present invention provides a process for extracting moisture from a PSU film, a PPSU film, or a PES film to render an essentially moisture-free film, the process including preheating the film in an oven at a temperature of from about 350°F to about 450°F for at least thirty seconds but not more than two hundred seconds .

A preferred embodiment provides a process wherein the film is in the form of a roll, sheet, or a disc, each respectively having a width of from about four inches to about six inches and a length of from about ten feet to about five hundred feet, and has a thickness of from about 15 mil to about 40 mil .

Another preferred embodiment provides a process wherein the film is in the form of a roll having a width of from about 5 inches and a length of from about 25 feet to about 100 feet . A further preferred embodiment provides a process wherein the film is in the form of a roll having a width of from about 5 inches and a length of from about 25 feet to about 60 feet .

Another preferred embodiment provides a process including preheating the film in an oven at a temperature of from about 400°F to about 420°F for at least 75 seconds but not more than 125 seconds . A further preferred aspect of this embodiment provides a process wherein the process includes preheating the film in an oven at a temperature of 410°F for 90 seconds . Yet another embodiment provides a process wherein the film is in the form of a roll, and further wherein the preheating oven includes an accumulator section to maintain the film in a dry condition . Yet another preferred embodiment provides a process wherein the moisture free film is cut into circular pieces from about 4 to about 6 inches in diameter . A further preferred embodiment provides a process wherein the moisture free film is cut into circular pieces having a 5 inch diameter .

Another aspect of the invention provides a process wherein the moisture free film pieces are subj ected to a thermoforming process using a device capable of stamping the circular pieces into a dental aligner . A further preferred embodiment provides a process wherein the circular film pieces have a thickness of from about 15 mil to about 40 mil . A further preferred embodiment provides a process wherein the circular film pieces have a thickness of about 20 mil .

The present invention utilizes an oven including a chamber with a belt like mechanism that is capable of moving the film through the oven as the film is being heated to temperatures of up to 500° F . These ovens can be custom manufactured to meet the specific requirements of a user .

The present invention also utilizes a thermoforming process that transforms a disc into a dental aligner, such as, for an example, a BIOSTAR®, which is a pressure molding machine with many applications in dental pressure molding and orthodontics Films in the form of a roll can also be transformed into dental aligners using similar techniques .

As shown in FIG . 3, a process 300 includes preheating (310) a stock film of PSU, PPSU, or PES in an oven at a temperature 350°F to 450°F for 30 to 200 seconds to generate a moisture-free film, the stock film in a form of a roll, a sheet, or a disc .

Process 300 cuts (315) the moisture-free film into pieces .

Process 300 subjects (320) each of the moisture-free pieces to a thermoforming process to produce a dental aligner .

Although only a few embodiments have been disclosed in detail above, other modifications are possible . All such modifications are intended to be encompassed within the following claims .