Patent Application
20220023006
Embodiments relate to mandibular repositioning appliances, and in particular to mandibular repositioning appliances customized according to the patient's specific tooth and jaw anatomy.
Individuals with less than ideal bite relationships often seek orthodontic treatments. Data from the third National Health and Nutrition Examination Survey (NHANES III) report that approximately 20% of the population have deviations from the ideal bite relationship (see, Proffit W R, Fields Jr H W, Moray L J. Prevalence of Malocclusion and Orthodontic Treatment Need in the United States; Estimates from the NHANES III Survey. Int J Adult Orthodon Orthognath Surg. 1998; 13(2); 97-106). This prevalence is consistent with global data that show approximately 74.7% of people have normal bite relationships while 25.3% are not ideal (see, Alhammadi M S, Halboub E, Fayed M S, Labib A, El-Saaidi C. Global Distribution of Malocclusion Traits: A Systematic Review. Dental Press J Orthod. 2018; 23(6)40.e1-40.e10).
Depending on the nature of the malocclusion, treatments may entail a variety of approaches and appliances, which may include extractions, growth modification, dental arch expansion, orthodontic treatment and jaw surgery. One of these approaches generally involves repositioning the jaw to a corrected or improved position.
Appliances for repositioning the jaw are historic and numerous. Some appliance designs are meant to simply dis-occlude the teeth and prevent them from contacting. These are commonly referred to as bite plates or bite planes. Other designs have channels to direct eruptive tooth movements in an anterior or posterior direction as indicated to help overcome the mal-relationship of the jaws. These are known as activators or bionators. Yet other designs have active components such as springs to push the jaw into a new position. An example of this design is the Herbst appliance. Another design approach, such as disclosed in U.S. Pat. No. 5,443,384, includes a two piece appliance with inclined planes on complementary blocks that interface between the upper and lower jaws so that when the patient bites down, the inclined planes of each block or piece contact and redirect the jaw to a new position. These appliances are commonly referred to as twin-block appliances. Furthermore, this entire group of appliances are commonly referred to as functional appliances or dentofacial orthopedic devices.
Although functional appliances are in common use, their design remains generic with respect to geometric dimensions of the active components. With respect to the bite plate/plane appliance and the design of the bite pad in it, the amount of appliance activation may be inappropriate for an individual if there is either insufficient dimensions (insufficient height) or excessive dimensions (too high) such that the patient experiences discomfort and is unable to tolerate and wear the appliance. Furthermore, due to the differences in individuals and sizes of the jaws as well as the different shapes of their condyles, the point of jaw rotation generally differs between individuals. The generic dimension of the bite pad may be insufficient to provide the desired amount of dis-occlusion or worse, may cause excessive amounts to overcome the adaptive ability of the patient's masticatory system and cause signs and symptoms such as jaw muscle ache, headaches, neck pain, temporomandibular joint dysfunction, tooth discomfort, tooth ache and others.
Accordingly, it is desirable to provide improved mandibular repositioning appliances and method of manufacturing the same.
The present embodiments provide improved mandibular repositioning appliances and methods of manufacturing the same. In particular, the present embodiments provide improved appliances that are customized according to the patient's specific tooth and jaw anatomy.
A specific personalized design of the dis-articulating component, the bite pad, based on the patient's natural anatomy which includes the contours of the teeth and the shape of their jaw joints provides information to design customized appliances for individuals to obtain desired clinical effects. Accordingly, the present embodiments provide a novel method to design a mandibular repositioning appliance which utilizes the patient's individual tooth and jaw joint anatomy.
Certain embodiments provide mandibular repositioning appliances customized based on the anatomical slopes provided by the maxillary incisors and/or the articulating surface of the mandibular condyles of the patient.
According to an embodiment, a method of repositioning a mandible of an individual is provided. The method includes acquiring a digital model of a dentition and/or a craniofacial anatomy of the individual, the digital model including a representation of a condyle or an incisal guidance or both the condyle and the incisal guidance. The method also includes calculating, based on the digital model, a slope of the condyle or a slope of the incisal guidance or both the slope of the condyle and the slope of the incisal guidance, and fabricating at least one removable orthodontic appliance including a feature configured to constrain a posterior or anterior movement of the mandible relative to the maxillae when worn by the individual, wherein a position of the feature is determined based on the slope of the condyle or the slope of the incisal guidance or both the slope of the condyle and the slope of the incisal guidance.
According to another embodiment, a removable orthodontic appliance configured to reposition a mandible of an individual is provided. The appliance includes a structure configured to mate with a geometry of a maxillary dentition and adjacent gum tissue of the individual, and a feature configured to constrain a posterior or anterior movement of the mandible relative to the maxillae when the appliance is worn by the individual, wherein the feature is located on the structure in a position based on a slope of a condyle of the individual or a slope of an incisal guidance of the individual or both the slope of the condyle and the slope of the incisal guidance.
According to yet another embodiment, a removable orthodontic appliance pair configured to reposition a mandible of an individual is provided. The appliance pair includes a first structure configured to mate with a geometry of a maxillary dentition and adjacent gum tissue of the individual, the first structure including a first feature located on an external surface of the first structure. The appliance pair also includes a second structure configured to mate with a geometry of a mandibular dentition and adjacent gum tissue of the individual. The first feature is located on the first structure in a position based on a slope of a condyle of the individual or a slope of an incisal guidance of the individual or both the slope of the condyle and the slope of the incisal guidance. The first feature is configured to constrain a posterior or anterior movement of the mandible relative to the maxillae when the appliance pair is worn by the individual. In certain aspects, the first feature includes a barb or hook type element, and the second structure includes a second feature located on an external surface of the second structure, and the second feature includes a complementary barb or hook type element configured to removably engage with the barb or hook type element of the first feature.
According to an embodiment, a tangible, non-transitory computer-readable medium is provided that has instructions thereon which, upon being executed by one or more processors, alone or in combination, provide for execution of methods described herein, such as, for example, methods for determining positional coordinates of the condyle and/or the incisal guidance, and calculating a slope of the condyle and/or a slope of the incisal guidance of an individual, based on a digital model of the dentition and/or craniofacial anatomy of the individual, and creating a digital file for use in fabricating a dental appliance or dental appliance pair or series of dental appliances or appliance pairs. An example of a digital file includes an STL file for use in 3-D printing a dental appliance or dental appliance pair.
Reference to the remaining portions of the specification, including the drawings and claims, will realize other features and advantages of the present invention. Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with respect to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.
The detailed description is described with reference to the accompanying figures. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items.
The present disclosure provides mandibular repositioning appliances and methods of manufacturing the same. The mandibular appliances of the present disclosure are advantageously customized based on the anatomical slopes of the patient's maxillary incisors and/or the articulating surface of the patient's mandibular condyles.
According to various embodiments, optimized dental appliances for repositioning of the individual's mandible relative to the maxilla and improving the individual's bite are designed according to the individual's unique craniofacial and dental anatomy to determine the coordinate changes in repositioning the mandible. The appliances contain the geometry of the dentition and adjacent gum tissues and may include constraining features designed to provide a biasing force created by the muscles of mastication when worn by the individual. For example, the constraining features may be configured to provide a biasing force that constrains a posterior or anterior movement of the mandible relative to the maxillae when worn by the individual.
In certain aspects, a series of removable appliances may be designed, with positional increments of biasing features to promote mandibular movement from an initial position to a new, desired position as directed by a dentist.
It should be appreciated that different imaging technologies may be used to acquire images of the dentition and the craniofacial anatomy proximal the mandibular condyle. A common point or points in different images of the dentition and the craniofacial anatomy may be identified to facilitate image combination. For example, the digital model may a combination of a radiographic image of the condyle and an intra-oral scanned image of the dentition. Once the image or images are acquired, the image(s) may be stored to a memory of a computer or processing system and rendered on a display device for viewing by a dentist or other user. The digital model presented on the display device may include a representation of the mandibular condyle or an incisal guidance or both the condyle and the incisal guidance.
At step 2, a slope of the condyle or a slope of the incisal guidance or both the slope of the condyle and the slope of the incisal guidance are calculated based on the digital model. For example, in an embodiment, a slope is automatically calculated based on relevant points (positional coordinates) in the digital model of the condyle and/or incisor. The relevant points may be automatically determined or identified by the processing system or the relevant points may be identified or selected by a user, e.g., using the user interface to manually select points on the condyle and/or incisor from which to determine the slope(s). In some embodiments, the processing system may automatically determine and identify multiple points on the condyle and/or the incisor from which the user may select for use in determining the slope(s). In other embodiments, the processing system may automatically determine and identify multiple points on the condyle and/or the incisor and also automatically calculate the slope(s) using a best fit equation or algorithm taking the multiple points as input. In other embodiments, other equations or algorithms for determining or calculating the slope may be used as would be apparent to one skilled in the art.
Each of the slope 15 of the condyle and slope 35 of the incisal guidance can be determined using the equation m=(Y2−Y1)/(X2−X1), where m is the slope and X1, Y1, X2 and Y2 are the relevant positional coordinates of the condyle 10 or the incisal guidance. In other embodiments, multiple relevant points may be determined or identified and a best fit equation or algorithm may be used to determine a slope using more than two relevant points.
Returning to
The barb or hook elements may be made of the same material as the appliances and should have sufficient resiliency to prevent separation once connected or engaged unless a threshold amount of lateral and/or posterior/anterior force is applied to the mandible by the wearing individual to separate or unhook the features to permit unhindered jaw movement.
In certain embodiments, a series or plurality of removable orthodontic appliances or orthodontic appliance pairs are fabricated. In certain embodiments, the position and/or orientation of the constraining feature(s) of each subsequent appliance or appliance pair may include an incremental positional and/or orientation change relative to the position and/or orientation of the constraining feature(s) of a prior appliance or appliance pair. A number of incremental positional changes and a size of each incremental positional change may be determined based on user input.
The complementary constraining features on maxillary appliance 50 and mandibular appliance 55 may be positioned and oriented so as to preferentially constrain an anterior movement or a posterior movement of the mandible with respect to the maxilla and thereby promote an anterior or posterior repositioning of the mandible over time with respect to the maxillae as determined by a dentist or other user. Any force on the mandible is created by the muscles of mastication due to the biasing of the constraining features rather than created directly by the appliances.
In certain embodiments, the occlusal area associated with the interacting geometries of the appliances and/or constraining feature(s) are customized for each individual, and the location in the arch (anterior, posterior) of the interacting geometries are customized for each individual. For example, an individual with an anterior open bite might have these interacting surfaces located in the posterior areas where there is occlusal contact. Alternatively an individual with posterior open bite, either naturally occurring or created with a bite plane or other appliance, might have these interacting surfaces in an anterior location.
In certain embodiments, each appliance (e.g., maxillary appliance 50 and mandibular appliance 55) may include a clear aligner fabricated using polymers or other clear material as is well known. In an embodiment, a dental appliance may be fabricated using a computer-assisted manufacturing process, such as 3-D printing based on a STL file generated by the processing system and provided to a 3-D printing system. In another embodiment, a dental appliance may be formed by a thermoforming process, e.g., a polymer-based material thermoformed over a mold of the dentition.
In certain embodiments, each constraining feature, e.g., shelf or ridge and/or hook or barb-type elements, may be formed integrally with the clear aligner. In other embodiments, such features may be formed separately from the appliance and attached or secured to the appliance. For example, in an embodiment, a constraining feature may be fabricated on a thin substrate which may be adhered or bonding to the appliance, e.g., clear aligner. The thin substrate may include the same material as the appliance or it may include a different material, such as a different polymer material.
As used herein, the terms “constrain” or “constraining” with regard to movement are not intended to exclude or tightly restrict movement, and generally permit or allow for at least some movement. For example, the constraining features provide for a planned repositioning of the mandible, yet the mandible remains free to open and close so it is not tightly constrained; the “constraining” features still permit or allow for movement of the mandible.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the disclosed subject matter (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or example language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosed subject matter and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Certain embodiments are described herein. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventor intends for the embodiments to be practiced otherwise than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
