Patent Application
20230070296
Not applicable
The work on which the disclosure of this application is based is not funded by any Federally Sponsored Research or Development in the United States of America.
The present invention pertains to instruments used for dental assessments or interventions for designing and making of aligners, dentures, and oral appliances or mouth guards for the prevention of snoring, sleep apnea, bruxism or similar other conditions, more particularly to a bite fork or bite tray that can be used for bite registrations to enable bite classification, jaw classification, or bite curvature measurement.
It is well known and documented that bite fork or bite tray is a useful instrument platform to record the position of maxillary or upper teeth relative to the cranial base. Mechanical and other jaw simulators typically use the information obtained by means of bite forks for design and manufacture of aligners, dentures and other oral or orthodontic appliances. A typical first step towards manufacture of an orthodontic or orthopedic appliance meant for closed bite cases, also known as oral appliances, is obtaining what is commonly known as a “construction bite” or “occlusion” registered using a bite fork (thus also known as bite fork registration or bite registration. As it is crucial to correspond occlusion with the proper alignment of teeth and jaw of a person in relation with the manufactured appliance, a convenient and accurate means to capture bite registration is important to eliminate or minimise potential misalignment.
Some of the information obtained by bite fork's bite registration are well known and established in the art. Broadly, bite registration is useful to estimate or measure a person's jaw class, bite class, or curvature of bite also known as occlusion. One or more of these classifications may be relevant to design and manufacture an appropriate oral appliance.
Bite classification or occlusion generally includes what is called Vertical Dimension of Occlusion (VDO) representing relationship between the upper or maxillary arch and lower or mandibular arch of human dentition. While VDO is the vertical dimension of occlusion, VDR is the Vertical Dimension of Rest, considered when a person or patient is fully relaxed. The difference between VDO and VDR is called “Freeway Space” or interocclusal space. When making a dental appliance, we are making it within these boundaries and the bite fork allows us to properly measure for this range that is why our bite forks also come in different thicknesses ranging from 0.5 millimeters to 10 millimeters suitable for verifying VDO of the person and in addition optionally verifying freeway space suitable for specific appliance being prescribed, designed or manufactured. For example, some appliances such as night guards do not need much “Freeway Space”, in that case we use a thinner bite fork. For other appliances, we may need thicker bite forks. Therefore, bite forks' selection is also based on the appliance being prescribed, designed and manufactured.
Generally, there are five types of bite classification: Class One, Class Two or overbite, Class Two—Division One, Class Two—Division Two, and Class Three or underbite, or other emerging classes. Bite classification is crucial to assess what is known in the art as malocclusion which is an incorrect relation or misalignment between the teeth of the lower or mandibular and upper or maxillary dental arches when they approach each other as the jaws of a person close. While Edward Angle's classification (Angle E. “Classification of malocclusion”. Dental Cosm.1899; 41:248-64) is most popular, there are several subsequent and emerging classifications known in the art.
Jaw classification determines relationship of the alveolar bone with respect to the person's dentition comprising of three types of classes including class one, class two, and class three, or other emerging classes (Graber™. Orthodontics Principles and Practice. 3rd ed., Philadelphia: W.B. Saunders; 1972. p. 155-6; Unger J W. Comparison of vertical morphologic measurements on dentulous and edentulous patients: J Prosthet. Dent. 1990, August; 64(2): 232-4).
Curvature of bite or occlusion comprises of three types of curves including Curve of Wilson, or Curve of Spee, or Curve of Monson, or other emerging curves (Kagaya K, Minami I, Nakamura T, Sato M, Ueno T, Igarashi Y. “Three-dimensional analysis of occlusal curvature in healthy Japanese young adults”. J Oral Rehabil 2009; 36:257-63; Ferrario V F, Sforza C, Miani A Jr. “Statistical evaluation of Monson's sphere in healthy permanent dentitions in man”. Arch Oral Biol 1997; 42:365-9; Patil P. “100 Years for Curve of Monson and Still Relevant”, International Journal of Prosthodontics and Restorative Dentistry. 2022; 11(3), 110).
Generally, a bite fork is of approximately horse-shoe shape to tally with the shape of a human dental arch, is smeared or loaded with semi-solid impression material externally and placed into a person's oral cavity between the maxillary and mandibular teeth. Subsequently, the person is asked to bite down on the bite fork enabling forming of a mold of the impression material capturing an impression of the person's teeth.
Some bite forks have been disclosed that include features for improvements in terms of convenience of use, stability, ability to scan teeth while taking the bite registration, and other such inventive steps.
Adell describes in U.S. Pat. No. 5,346,395 dated Sep. 13, 1994 titled “Dental Arch Bite Registration Device” a device that consists of multi-laminar structure fabricated from ethylene vinyl acetate using injection molding process to bond one lamina to another without the use of any adhesive wherein the different lamina have different durometer properties.
Jacobs and Jacobs describe in U.S. Pat. No. 5,562,449 dated Oct. 8, 1996 titled “Custom Dental Tray” a dual dental tray assembly which includes a pliable resilient outer dental tray using a pre-formed thin inner tray of thermoplastic material that nests inside the pliable outer tray. Although Jacobs's disclosure does not directly relate to a bite fork which is the subject of current disclosure, the use of thermoplastic material has common ground as the two trays are heated to between 145°-160° F. resulting in the inner tray becoming more formable, allowing for the inner tray to be accurately formed over the patient's teeth. Subsequent cooling to room temperature makes the tray hard and rigid retaining the acquired shape.
Patent application DE20105234U1 titled “Ready-to-use bite fork for single use in dental technology” published dated 5 Jul. 2001 describes a bite fork having a U-shaped bite section and a holding section along with partial reference pad supports and a torsion-resistant carrier.
Karapetyan describes in U.S. Pat. No. 7,220,123 dated 22 May 2007 titled “Device For Registration of the Dental Bite” a two-piece device for dental bite registration, each generally of a half-U-shaped configuration, coupled with one another forming a full U-shape with provision in the handle to lock them together.
Patent application DE202011105953U1 published dated 20 Oct. 2011 titled “Bite fork and bite-taking set” describes a bite fork with impression material having a bite recording part with a first fastening means, and a position marking part with second fastening means matching the first fastening means, which is detachably connected to the bite recording part.
Patent application DE202015105356U1 published dated 12 Oct. 2016 titled “Bite fork with bars” describes a bite fork with bite surface recesses to enable partial visualization of the tooth surfaces by 3D surface scanner and markers while the bite fork is placed in the oral cavity of a patient. In a substantially similar disclosure, Brunner describes in Patent publication EP2964136B1 dated 10 Mar. 2021 titled “Bite fork with recesses” (a version also published earlier as WO 2014/135160 dated 12 Sep. 2014), a bite fork comprising of a first processing means for correlating the image of the tooth surfaces and the position data of the bite fork to provide a true to space coordinate image of the tooth surfaces, a para-occlusal tray to be attached to the teeth with further position marker elements, a second position detection means adapted to the further position marker elements for the ongoing position detection of the para-occlusal tray during movements of the dentition, and respective processing means.
Kopp describes in U.S. Pat. No. 8,123,521 dated Feb. 28, 2012 titled “Device for the Registration of the position of a protruding mandible” a bite fork type device albeit for a different purpose of registration of a mandibular position that is protruded relative to the normal position, with an U-shaped impression plate having finger like registration surfaces.
Kerschensteiner and Christen describe in U.S. Pat. No. 10,299,898 dated May 28, 2019 titled “Method for preparing a partial or full dental prosthesis” a broad process for preparing dental prosthesis that includes preparation of bite plates or forks along with a review of Angle's bite classifications (Angle classes as described in Lehrbuch der Zahntechnik, Volume 1, A. Hohmann/W. Hielscher, Quintessenzverlag, pp 130/131).
Charkhandeh describes in U.S. Pat. No. 10,751,153 dated Aug. 25, 2020 titled “Apparatus and method for registration of a digital dental bite” yet another configuration of a bite fork for obtaining digital open bite registration including at least one molar pad and at least one incisor pad, each of the pads having respective upper and lower bite surfaces, with further option of inclusion of a band extending between the molar pad and the incisor pad. The application of this is directed mainly towards manufacture of oral appliances for Obstructive Sleep Apnea (OSA) patients.
Ackel describes in U.S. Pat. No. 11,096,764 dated Aug. 24, 2021 titled “Dental Tray Molding Kit and Method for Dental Molding” a method for dental tray molding that includes providing a generic tray, heating a thermoformable member until sufficiently pliable, placing the thermoformable member over the generic tray, placing a deformable spacer member over the thermoformable member, applying a biting force from a user onto the thermoformable member through the deformable spacer member, cooling the thermoformable member and separating the thermoformable member, whereby the thermoformable member forms a custom dental tray. Here the bite fork is provided as a kit component part of the dental tray molding kit.
These and similar other bite forks, however, are all requiring application of impression materials on the surfaces of the bite fork externally and manually, without any more efficient and controlled means to do the same. Manual application by scoop, putty applicator or spoon type devices does not ensure even and just adequate quantity of impression material distribution over the bite surfaces. Furthermore, most of the bite forks currently available do not have the flexibility to comply with the curvature of the bite.
The objective of the invention is to improve the convenience, quality, and accuracy of impression material application on one or more surfaces of the bite fork device. As bite fork is a very common and extensively used device in the field of oral appliances design and manufacture, improvements in the same has significant and considerable impact on the users of the device. A bite fork is used by dental professionals including dentists, orthodontists, prosthodontists, denturists, etc. for prescription of a variety of orthodontic appliances such as aligners, retainers, night guards or mouth guards, sleep apnea treatment oral appliances (e.g. Mandibular Advancement Devices or Stents), anti-snoring devices, dentures, and several others. A bite fork may also be self-administered by a user or patient in a home or clinical setting, likely following written, oral, or other means of instructions from a professional. As examples, let us consider two of the major markets where bite forks are used by dentists and denturists: aligners and dentures.
According to the SEC archives (United States Securities and Exchange Commission, Registration No. 333, Form S-1 filed on Aug. 16, 2019), the major emerging market share holder of aligners, SmileDirectClub® Inc. submitted that the global orthodontics market is estimated as approximately 500 million people, the U.S.A. market leading at approximately 124 million people. It is also postulated in this filing that probably 85% of people worldwide have malocclusion, out of which less than 1% are only treated annually, leaving a huge scope for expansion of this market in future. As bite registration is an important step in design and manufacture of aligners, this is a significant opportunity to improve the functionality and user convenience during registration of a patient's bite. As so-called clear aligners are poised to be emerging as direct-to-consumer (DTC) orthodontics with newer entrants such as SmileDirectClub® Inc. leading the way (Wexler et. al., “Direct-to-Consumer Orthodontics: Surveying the User Experience”, J. Am. Dent. Assoc. 2020 August; 151(8): 625-636.e4; doi: 10.1016/j.adaj.2020.02.025), user experience in terms of ease-of-use features is becoming even more important.
According to several estimates quoting the Journal of Prosthetic Dentistry, 37.9 million Americans were estimated to require dentures in 2020 (Douglass et. al. “Will there be a need for complete dentures in the United States in 2020?”, J. Prosthet Dent. 2002 January; 87(1):5-8. doi: 10.1067/mpr.2002.121203). That's nearly 9% of the United States population. As Canadian population is approximately 0.11 of the USA population (Simon Fraser University. Population Comparison of Canada, United States, and Mexico: Profile Report, World Population), assuming similar North American demographics, the estimated denture users in Canada are 4.17 million, adding up the potential application of the disclosed invention's improvement benefits reaching to about 42 million. The overall bite fork user market is much larger than this, likely about three times of this considering younger populations too needing devices such as aligners, mouth guards, anti-snoring, obstructive sleep apnea treatment devices and several other oral or orthodontic appliances that require bite registration as a preliminary step, as stated earlier. By providing features in the bite forks that makes use of them for bite registration more convenient, faster, using less impression material by even and just adequate amount of application, and enabling flexibility for capturing curvature aspects of the bite registration, we would be providing a pioneering solution not available in the market currently.
Therefore, we can conclude from this brief of the statement of the object of the invention that filling a much desirable gap in the field by providing improved solution to a substantial number of users of bite forks involved in design and manufacture of oral appliances would be of immense benefit.
The preferred embodiment of disclosed invention provides additional features in a bite fork substrate to facilitate easy connectivity with an impression material source, a means to pump the impression material through channels inside the substrate, enabling effusion of the material from orifices or openings on the substrate where the bite impression is specifically needed. The pumping process can be done after insertion of the substrate inside a patient's oral cavity. This approach enables uniform distribution of the impression material, while minimizing the amount of impression material, by pumping just necessary and adequate quantity of the impression material.
According to one aspect of the invention, the bite fork substrate may be provided with a snap fit, threaded, or a clamping mechanism such as a worm clamp or spring clamp for ease of connectivity and dis-connectivity between the substrate and the impression material source. According to another aspect of the invention, the impression materials source may be integrated with a manual pumping mechanism to pressurize the flow of the material into the bite fork. Additionally, and optionally, the pumping mechanism may be motorized by integration of a miniaturized electric pump. Those skilled in the art may appreciate that there can be several configurations of locations of integration of the pump with the impression materials source and the bite fork substrate, for example, direct pressurization of impression material or indirect pressurization such as through air or hydraulic pressure from a relatively distant location, enabling the bite fork assembly to be light and compact while held inside a person's oral cavity.
Courting to another aspect of the invention, the substrate has internal or external channels to facilitate passage and flow of the impression material from the source to the destination region where the bite registration is realized. Optionally, but preferably, the channels may be internal and cylindrical shaped. Other shapes of channels such as square or rectangular or triangular, or elliptical cross sections may also be deployed as they are realizable conveniently if the substrate is made using additive manufacturing or 3D printing technology which is the preferred mode of manufacturing under this disclosure. However, other modes of manufacturing such as injection molding or milling and drilling or other methods that may be available in the state-of-the-art are also covered under the spirit and scope of the invention, although they may have limitations, for example the channels if formed by drilling may only be cylindrical in shape. made of light weight flexible bio-compatible material such as Nylon-12 or a stretchable bio-compatible elastomer. The substrates may be manufactured by several alternative means such as molding, 3D printing or additive manufacturing, or milling.
The bite fork substrate may be made of light weight flexible bio-compatible material such as Nylon-12 or a stretchable bio-compatible elastomer. Broadly, the substrate may be made of plastic material such as bio-compatible Polyamides, Polyolefins, Polyesters, Fluoropolymers, Elastomers, Poly-p-xylylene, Polystyrenes, Biopolymers, Resins and several other combinations and reinforced hybrid materials. Preferably, but optionally, the bite fork substrate may be made of a bio-compatible thermoplastic such as Polyform, Methacrylate, or Ethylene Vinyl-acetate, such as Elvax 250, manufactured by DuPont®, Wilmington, Del., USA.
Courting to yet another aspect of the invention, optionally, but in addition, the impression material pumped may be formed of multi-layer hybrid construction wherein a stronger (when solidified and hardened) impression material layer forms the core to provide strength and stability of impression areas in contact with teeth or gums over which softer impression material is layered allowing a combination of both strength as well as flexibility. The softer material, if constrained by barrier means surrounding the impression areas, may act as spring to ensure tighter and more compact and thus more accurate bite registration. The multi-layer construction may be achieved by several alternative pumping approaches such as simultaneous pumping of different impression materials from different channels, and sequential pumping of different impression materials from same channels.
According to an additional but optional aspect of the invention, one or more deflectors, valves or other means or combinations of the same are sequentially or concurrently deployed for enabling controlled distribution of ejection of the impression material from the different openings. Optionally, the control of ejection of material is based on feedback from at least one or more sensors.
According to another additional but optional method of use of the invention, bite or occlusion classification of a person to determine malocclusion by recording vertical dimension of occlusion pertaining to upper and lower arch of the person's dentition may be acquired. Additionally, but optionally, jaw classification of a person to determine relationship of the alveolar bone with respect to the person's dentition may be obtained. Furthermore, additionally, but optionally, curvature of bite or occlusion may also be obtained.
In summary, the disclosed invention of a bite fork device with provision for pumping impression materials offers considerable improvement and advantages over those described in prior art in general, as a more convenient to use with just appropriate application of impression material in particular.
The figure shows a configuration of mandibular and maxillary dentures in relation with the lower and upper jaws of a user respectively, pointing out the locations of different anatomical parts of interest in view of the disclosed inventive aspects of a bite fork for bite registration. The jaws of user are shown in an open state to be able to view the internal parts of oral cavity of the user, along with a view of a bite fork substrate inserted and held between them. The lower jaw has lower gum (also called gingiva) part 10 placed over a bone structure 11 in the mandible. The bone structure extends to the back as a Temporomandibular Joint (TMJ) 15 comprising of parts known in the art as condyle 12, fossa 13, and disc 14. The mandibular denture 20 is placed over the lower gum 10 in a reasonably tight but comfortable fit and remains retained during day-to-day activities of the user such as speaking, chewing, etc. In a standard denture that does not use any implants to secure the denture to the mandible, the shape and fit between the mandible and the mandibular denture serve the purpose of retention.
The user is generally provided with options for increased levels of retention, for example, by inserting or applying between denture 20 and gum 10 bio-compatible human use safe adhesive materials claiming several characteristics such as being Zinc free, impervious to water, providing soft cushion, quality seal from food particles, ooze-control, use of natural ingredients like gum wax, beneficial herbs, and vitamins. Several adhesive products are available, for example, Effergrip® denture adhesive cream (manufacturer: Prestige Consumer Healthcare, Irvington, N.Y.; Source: Amazon® USA), Fixodent® Ultra Max Hold Dental Adhesive (Procter & Gamble®, Cincinnati, Ohio, USA), SECURE® Sensitive Adhesive (Cutting Edge International, LLC, Los Angeles, Calif., USA), Instant Smile™ Secure Fit Adhesive (Billy Bob Products Inc., Hardin, Ill., USA), Super Poligrip® Denture and Partials Adhesive Cream (Glaxo Smith Kline, Philadelphia, Pa., USA), Corega® Denture Adhesive Cream (Glaxo Smith Kline, Bulgaria, Source: Amazon®, USA), Y-Kelin Denture Adhesive Cream (Anhui Greenland Biotech Co. Ltd., Bengbu, Anhui, China), DenSureFit® Lower Denture Reline Kit (OTC Dental Inc., Vancouver, Wash., USA), and from many other manufacturers or sources.
The use of adhesive between denture and gum is found to achieve good average retention force in compliance with reported research, for example, in the range of 16.66±7.32 lbs for milled denture bases and in the range of 12.19±6.15 lbs for the conventional heat polymerized denture bases (AlHelal, Abdulaziz Abdullah, “Comparison of Retention between Milled and Conventional Denture Bases: A Clinical Study” (2016), Loma Linda University Electronic Theses, Dissertations & Projects, 323). Our experimental tests have shown that 3D printed dentures provide better or at least comparable retention force relative to milled denture bases. We have found that this retention force is adequate to withstand the mandibular advancement force reported in the art as approximately 1 to 1.2 Newtons per millimeter of mandibular advancement (for example, 1.18 Newtons per millimeters as per J Cohen-Levy, B Pételle, J Pinguet, E Limerat, B Fleury, Sleep Breath, 2013 May; 17(2):781-9. doi: 10.1007/s11325-012-0765-4. Epub 2012 Sep. 11).
The mandibular denture 20 comprises of an exterior wall or flange 21, an exterior ridge or border 22, and an interior ridge or border 23. A cavity known in the art as trough is formed between the exterior and interior walls that fits over the lower gum 10. A set of teeth 25 that substitute natural teeth known in the art with nomenclature (starting from back or TMJ side, a set of teeth—one on left and one on right sides) Second Molar, First Molar, Second Premolar, First Premolar, Canine or Cuspid, Lateral Incisor, and Central Incisor (front most teeth set) are embedded symmetrically in the mandibular denture in a U-shaped configuration. This is considering the prevailing trend of not having Third Molar or Wisdom teeth at the back most location, like the natural teeth set where their extraction is recommended by dentist profession, resulting in a total fourteen teeth in the mandibular denture.
Analogous to the mandibular denture 20, the maxillary denture 30 comprises of an exterior wall or flange 31, an exterior ridge or border 32, and an interior ridge or border 33. A cavity known in the art as trough is formed between the exterior and interior walls that fits over the upper gum 16. Generally, an impression of upper palate of user's oral cavity is obtained to provide a bridge between the left and right sides of interior walls in the maxillary denture. This bridge part known as Palate 34 generally is in close contact with the user's upper palate helping in improved retention of the maxillary denture. The maxillary denture 30 is placed over the upper gum 16 in a reasonably tight but comfortable fit and remains retained during day-to-day activities of the user such as speaking, chewing, etc. In a standard denture that does not use any implants to secure the denture to the maxilla, the shape and fit between the maxilla and the maxillary denture along with palatal contact serve the purpose of retention. The user is generally provided with options for increased levels of retention, for example, by inserting or applying between denture 30 and gum 16 bio-compatible human use safe adhesive materials claiming several characteristics as mentioned earlier in the context of mandibular denture. A set of teeth 35 that substitute natural teeth known in the art with nomenclature (starting from back or TMJ side, a set of teeth—one on left and one on right sides) Second Molar, First Molar, Second Premolar, First Premolar, Canine or Cuspid, Lateral Incisor, and Central Incisor (front most teeth set) are embedded symmetrically in the maxillary denture in a U-shaped configuration. This is considering the prevailing trend of not having Third Molar or Wisdom teeth at the back most location, like the natural teeth set where their extraction is recommended by dentist profession, resulting in a total fourteen teeth in the maxillary denture.
While a case with full dentures using a bite fork for bite registration described above is useful to check the suitability of an existing or old denture, and to design and manufacture a better fitting, updated or new denture set, the invented bite fork under current disclosure has broader applications for those with full natural teeth. In those cases, we may consider
The configuration of
The disclosed bite fork or bite tray may be more conveniently used by dental professionals including dentists, orthodontists, prosthodontists, denturists, etc. for prescription of a variety of orthodontic appliances such as aligners, retainers, night guards or mouth guards, sleep apnea treatment oral appliances (e.g. Mandibular Advancement Devices or Stents), anti-snoring devices, dentures, and several others. The disclosed bite fork or bite tray may also be used in conjunction with an analog or digital face bow. A bite fork may also be self-administered by a user or patient in a home or clinical setting, likely following instructions from a professional. It may be sent to a patient as a kit either stand-alone or as part of an impression tray kit.
Broadly, a preferred embodiment of disclosed system is useful for obtaining inside a person's oral cavity a bite registration consisting of full or partial teeth impression or full or partial gum impression or alveolar bone or alveolar process or alveolar ridge or a combination of these. Edentulous maxillary and mandibular Jaw Segments (EJS) consist of alveolar and basal bone. EJSs are attributed to non-aesthetic and aesthetic maxillary or mandibular zone, because the requirements and risks of aesthetic result achievement differ significantly in so called non-aesthetic zone in comparison with aesthetic zone. Alveolar bone or alveolar process or alveolar ridge are terms used to capture the relationship of associated soft tissue or exposed surface layer with respect to the dentition of a person or patient.
In an additional optional embodiment, the disclosed system may also be used for functioning as a dental impression tray. In such an optional embodiment, additional enclosure means to constrain the flow of the impression material around the teeth or gums is deployed to control and enhance the contact pressure between the teeth or gums or alveolar bone or alveolar process or alveolar ridge and the impression material in order to obtain a relatively more accurate and representative impression.
The bite registration obtained and/or dental arch impression obtained is directed towards bite or occlusion classification, or jaw classification, or both bite and jaw classification useful for prescribing or designing or manufacturing of denture set such as Removable Partial Dentures or Removable Full Dentures, or useful for manufacture of oral appliances worn over either natural or prosthetic teeth or a combination in case of anti-snoring devices, mandibular advancement devices, aligners, or mouth guards or plurality of oral appliances.
Three different bite fork types and uses are disclosed; namely, edge to edge dual arch, non-edge to edge dual arch, and single arch. The edge to edge dual arch type can be deployed where the incisors of the upper and lower arch meet in a parallel path or aligned to each other. The non-edge to edge dual arch type of bite fork may be deployed where it is desired that patients can bite in any position including fully retruded, natural, to fully protruded or maximum advanced. The dual arch bite forks are generally used for obtaining the bite registration or impression or to obtain therapeutic position for dual arch appliances such as mandibular advancement devices (MADs) or night guards or mouth guards that cover both upper and lower arch. An appropriate therapeutic position of an oral appliance is defined as a position of the mandible that achieves improvement of symptoms, signs, or objective indices of disorders that are related to sleep and breathing such as Obstructive Sleep Apnea.
The single arch type of bite fork is generally meant to be used for obtaining the bite registration or impression or to obtain therapeutic position for single arch appliances such as a mouth guard or night guard for only one of maxillary or mandibular arch. It may be deployed where patients can bite in any position including fully retruded, natural to fully protruded or maximum advanced. However, in an additional optional embodiment it is possible to use it for registration of dual arch (both maxillary and mandibular parts) too.
It may be appreciated that the channel path and design 540 is only an example, and there may be several different patterns of the same, all of them covered by the spirit and scope of this disclosure. The substrate may have a plurality of internal or external channels or combination of them for conveyance of the bite registration material or impression material and multiple openings for the material to eject from the openings. Although not shown in this Figure, channels may also be external wherein retention and flow of material is achieved by gravity. Furthermore, optionally at least one or more deflectors, valves or other means or combinations of the same may be sequentially or concurrently deployed for enabling controlled distribution of ejection of the bite registration material or impression material from the different openings. In addition, optionally, the control of ejection of material is based on feedback from at least one or more sensors that are deployed in the channels or the substrate or any other part of flow path such as in the connection to the pumping means.
It may be appreciated by those skilled in the art that features such as breaking lines, retention lines, integrated impression material source or mixer connection with substrate, and other several features are common optional features that are applicable to all the disclosed embodiments and their perceptible variants, and although they are illustrated and described as examples in particular embodiments in this description, application to all other variants are covered by the spirit and scope of disclosed invention.
We have experimented with several substrate materials, impression materials and their combinations, and several alternative means to connect the source of impression materials with the substrate both with and without exclusive mixer component.
The bite fork substrate may be made of light weight flexible bio-compatible material such as Nylon-12 or a stretchable bio-compatible elastomer. Broadly, the substrate may be made of plastic material such as bio-compatible Polyamides (e.g., Nylon-12, Nylon 6, Nylon 11, Nylon 66, Polyether Block Amide), Polyolefins (e.g., Polyethylene, Polypropylene, Cyclic Olefin Co-polymers, Polyvinyl Chloride), Polyesters (e.g., Poly butylene terephthalate, Poly ethylene terephthalate), Fluoropolymers (e.g., Polytetrafluoroethylene known with trade name Teflon, PVDF, FEP, ePTFE), Elastomers (e.g., Silicones, Thermoplastic elastomers), Poly-p-xylylene (Parylene), Polystyrenes (e.g., Polyformaldehyde, Polyurethanes), Biopolymers, and several other combinations and reinforced hybrid materials. The impression material pumped may be formed of multi-layer hybrid construction wherein a stronger (when solidified and hardened) impression material layer forms the core to provide strength and stability of impression areas in contact with teeth or gums over which softer impression material is layered allowing a combination of both strength as well as flexibility. The softer material, if constrained by barrier means surrounding the impression areas, may act as spring to ensure tighter and more compact and thus more accurate bite registration. The multi-layer construction may be achieved by several alternative pumping approaches such as simultaneous pumping of different impression materials from different channels, and sequential pumping of different impression materials from same channels.
In addition, optionally the bite forks may be provided in several different colors to assist in classification of the bite forks depending on size ranges. The color coding helps in ease of identification of a range with the size requirements of patients depending on their sizes of mandibular or maxillary arches.
Preferably, but optionally, the bite fork substrate may be made of a bio-compatible thermoplastic such as Polyform, Methacrylate, or Ethylene Vinyl-acetate, such as Elvax 250, manufactured by DuPont®, Wilmington, Del., USA. A thermoplastic substrate becomes flexible when heated for about 60 seconds (for example, by placing under warm water or other alternate heating means such as placing in front of blower with hot air or any other warming means requiring less or more durations of time), then inserted in the oral cavity of a person, followed by bite by the person for a required duration to enable appropriate registration of bite curve, then removal from the oral cavity and optionally further cooled for a required duration (for example, by placing under cold water for 30 to 60 seconds, or other alternate cooling means such as placing in front of blower with cool air or any other cooling means requiring less or more durations of time) if necessary to enable the substrate to attain relatively higher rigidity for recording of said bite curve registration.
A variety of bite registration impression materials may be used for bite fork registration or other impression materials for capture of left or right side of a patient's upper or maxillary, and/or lower or mandibular arch. Vinyl Poly Siloxane (VPS), Poly Vinyl Siloxane (PVS), and Alginates are most commonly used. Broadly, impression materials are classified as rigid or inelastic and elastic. Rigid or inelastic impression materials include impression plasters, impression compounds, impression waxes and Zinc Oxide Eugenol. Elastic impression materials include Hydrocolloids such as reversible Agars and irreversible Alginates. Elastomeric impression materials include Polyether, Condensation Silicone, Polyvinyl Siloxane, and Polysulfide.
A few examples used during prototype experiments of the disclosure are as follows. Alginate impression material Cavex ColorChange™ has elastic and color changing properties (Cavex Holland B V, Haarlem, Netherlands). It turns from violet to pink that indicates end of mixing time (in 30 to 60 seconds), turns from pink to white that indicates end of setting time (in about 60 seconds), and turns from white to pink to indicate that the impression is fully cured (in about 30 minutes time). Several varieties of Maxill® products (Maxill, St. Thomas, Ontario, Canada) and Henry Schein® products (Henry Schein, Melville, N.Y., U.S.A.) were also experimented along with several other brands available internationally. The bite registration materials or impression materials used with the system were typically semi-solids or liquids that solidify after some time or mixture of multiple liquids or mixture of liquid and solid substances that solidified after some time, for example, after 30 seconds to 30 minutes.
It may also be appreciated by those skilled in the art that additional and optional configurations of the disclosed invention may enable embodiments as variants for additional specific functionalities, covered by the spirit and scope of disclosed invention. For example, in a variant (
