PROSTHESIS

FIELD OF INVENTION

[0001] The present disclosure relates to devices and methods for acquiring impressions and making casts for fabrication of dental prostheses, such as dentures.

BACKGROUND

[0002] Construction of dental prostheses such as dentures and their successful performance during use by the patient depend on obtaining an accurate impression of the prostheses supporting areas. When a patient visits a dentist for getting dental prostheses such as dentures, the dentist first assess the oral cavity, the tissue areas, the jaw, and any remaining teeth. The dental professional takes impressions to construct bite blocks. If stock trays are not used, these impressions can be used to construct custom trays for functional impression so that border molding and impression can be made. This impression is sent to the lab. If stock trays are used, then the dental professional can make functional impression at this time. The lab can use this impression to fabricate bite blocks on stone models made from impressions.

[0003] The lab fabricates bite blocks and custom trays if the dental professional opts to go with custom trays. A common practice is to use stock trays to acquire functional impressions. Border molding is needed for custom tray and stock tray. Border molding allows the tray to be fitted into the mouth such that it sits passive and does not impinge on any anatomical structure such as facial muscles. The lab takes about two weeks to provide the bite blocks back to the dental professional. [0004] During the next visit by the patient, the dental professional takes bite records using the lab-provided bite blocks. The vertical dimension, lip line, midline, and smile line are recorded on this lab-made bite block. The tooth shade and mold are selected at this time. These bite blocks have several disadvantages. They are bulky, and displace upper and love lip more labially. The dental professional can have difficulty in acquiring an accurate record if the patient is biting in protrusive or is giving incorrect centric relation. It is also difficult to get proper vertical dimension as it is bulky and causes the patient's lips to protrude. The dental professional has to trim or add more wax to get proper vertical dimension. The trays that hold wax have suction problems and are hard to use. If the dental professional requested a custom tray, then functional impressions will be taken at this time. The bite block with all the recordings is sent to the lab, where wax-based dentures are fabricated for the patient to try during the next visit. This fabrication step takes about one to two weeks.

[0005] Once the wax-based dentures are ready, the patient comes in for a third visit. The dental professional evaluates the patient's comfort level, the dentures' fit in the oral cavity for aesthetics, function, and phonetics and for patient approval. If changes are needed, a new bite is taken with instructions to the lab of the required changes. This step is repeated until dentures are made to fit satisfactorily and can often take two to four visits with five to ten working days in- between the visits. After a satisfactory fit, the laboratory processes the record and creates the dentures in acrylic for final delivery in five to ten working days. The dental professional fits the patient with the final product.

BRIEF SUMMARY

[0006] The Applicants recognize the importance of creating an accurate record for the fabrication of dental prosthesis, including dentures. Various embodiments of methods and apparatus for creating an accurate record for the fabrication of dental prosthesis, including dentures are provided herein. Exemplary embodiments of the apparatus include a dental impression recording device. This device includes (a) an upper tray including a first ridge zone configured to receive impression material and a platform configured to record tracings; (b) a lower tray including a second ridge zone configured to receive impression material and a bridge configured to accept a connector; and (3) a connector configured to lock the upper and lower tray at a predetermined height. In certain embodiments, the platform of the upper tray is coated with recordable material to record tracings. In certain embodiments, the recordable material is graphite or paint. In certain embodiments, the bridge has a threaded perforation. In certain embodiments, the connector has a screw thread to engage with the threaded perforation of the bridge. In certain embodiments, the impression material is chosen from a group consisting of irreversible hydrocolloid (alginate), polysulfide (rubber base), polyether, or zinc oxide/eugenol materials, silicone, VPS materials, polyvinylsiloxane, or combinations thereof.

[0007] Exemplary embodiments of the invention include methods of using a dental impression recording device to capture a dental record for manufacturing dental prosthesis such as dentures. An exemplary method includes first making an impression of the upper ridge using upper tray. Impression materials, like polyvinylsiloxane, are dispersed in the ridge zone of the impression trays. The dental professional holds the tray until the impression material sets and an impression is produced. Then the tray is removed. The process is repeated using the lower tray to obtain an impression of the lower ridge of the patient. Tracing of the arch is performed using upper tray using the Gothic Arc tracing method, specifically the active method. The connector is placed onto the bridge of the lower tray and is used to secure the trays at the proper height. The proper vertical dimension for the particular patient is determined using one of a variety of measuring devices including but not limited to a caliper, a ruler, or scriber with a lock. From the tracing results, the dental professional makes an indentation in the upper tray to accommodate the connector from the lower tray, at the location where the three lines cross on the tracings or at the position determinative of the correct centric relation. The upper and lower trays are assembled back and placed into the oral cavity of the patient. After appropriate placement, bite registration material is injected and allowed to sets, thus creating the record. Vertical dimension, centric relation, midline, lip line, smile and position of maxillary two central teeth are recorded using the apparatus described herein, thus creating the bite record. The tooth shade and mold are selected. These records are sent to the lab for denture fabrication in wax, which takes about five to ten working days.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Non-limiting embodiments of the present disclosure are described by way of example with reference to the accompanying figures which are schematic and are not intended to be drawn to scale. Unless indicated as representing the background art, the figures represent aspects of the disclosure. So that the manner in which the features and benefits of the invention, as well as others which will become apparent, may be understood in more detail, a more particular description of the embodiments of the invention may be had by reference to the embodiments thereof which are illustrated in the appended drawings, and which form a part of this specification. It is also to be noted, however, that the drawings illustrate only various embodiments of the invention and are therefore not to be considered limiting of the invention's scope as it may include other effective embodiments as well.

[0009] Fig. 1 is a representation of the upper tray, according to an exemplary embodiment of the invention. [00010] Fig. 2 is a representation of the edges of the upper tray, according to an exemplary embodiment of the invention.

[00011] Fig. 3 is a representation of the lower tray, according to an exemplary embodiment of the invention.

[00012] Fig. 4 is a representation of the pin, according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION

[00013] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, which illustrate various embodiments of the invention. This invention, however, may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is to be fully recognized that the different teachings of the various embodiments discussed below may be employed separately or in any suitable combination to produce desired results. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the various embodiments, and by referring to the accompanying drawings. In the drawings and description that follow, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale. Certain features of the disclosure may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. [00014] During the production of dental prostheses, the dental technician obtains an impression of the oral cavity and surroundings, usually of the toothless or a partially toothed jaw. Described herein is an apparatus that provides a single unit for making mold for dentures. Certain embodiments of this apparatus are used for preparing full dentures or for partial dentures where one ridge is edentulous. A full denture is made to restore both the teeth and the underlying bone when all the teeth are missing in an arch. When used for preparing partial dentures, one would adjust for vertical dimension.

[00015] The apparatus comprises at least two impression trays- an upper tray and a lower tray. An impression tray is a device that is configured to contain or control an impression material for making an impression. Although impression trays can be either stock or custom trays, currently most dental professionals use stock trays. Impression trays used herein can be in a variety of different shapes and sizes to cater to the diversity of sizes of the oral cavities of patients. Stock trays will come in different sizes, such as small, medium, large, or universals, or adjustable as appropriate. Large or extra large sizes to accommodate special arches. The impression trays are made of one of the many FDA approved materials such as acrylonitrile butadiene styrene, or other materials including but not limited to acrylic resins, plastic, silicone, metal, or combinations thereof. These impression trays can be made of disposable resin or autoclavable metal or a combination thereof.

[00016] Impression materials include but are not limited to vinyl polysiloxane, poly ether, rubber base, silicone, alginate substitutes, or other such material capable of being used to take impression of the ridges. Impression materials can be hand mixed or mixed using devices such as auto gun mixers. Impression materials are mixed and dispersed into the impression trays using a variety of techniques including manual dispersion, filling using cartridges, or other techniques known to a person skilled in the art. In certain embodiments, the impression materials are held on to the tray using adhesives - can be manufacture recommended to help the adhesion of the impression material to the tray.

[00017] Certain embodiments contain an upper tray with a platform to record the trace and a lower tray to hold a connector. The upper tray has two parts: (1) a ridge zone that is configured to house an impression material for taking the ridge impression, and (2) a platform to record the tracings. The lower tray comprises a bridge configured to hold a connector and a ridge zone that is configured to house an impression material for taking the ridge impression. The connector can be a pin, or a screw, or a bolt, or other mechanisms that can connect the upper and lower tray at progressive heights. In certain embodiments, the pin is configured to fit into a predetermined perforation in the bridge of the lower tray. In certain embodiments, the pin has a threaded component to move the pin up and down and progressively adjust the height between the upper and lower trays. The perforation in the bridge can be threaded to receive the threaded end of a pin or a screw. The lower tray may contain an indentation that is configured to detect if the tray tilts up during the process.

[00018] Certain embodiments include other perforations in the upper and lower impression trays in the ridge zone to reduce the potential for pressure created when the impression material confined in the ridge zone is molded to fit the ridge and create an impression. These perforations also facilitate leakage of impression material that helps secure the impression material when the impression is taken. The material that comes out through the perforation will help to secure or bond the impression material used. This material also helps secure the record and facilitates reassembly if the impression material separates from the tray. Other materials such as adhesives can also be applied to the tray in the region where the registration material will be placed. [00019] An exemplary embodiment of the upper tray 100 is shown in Fig. 1. The upper tray has two parts: a ridge zone 102 and a platform 104. The platform is configured such that a marking material can be coated on the surface facing the lower tray. There are also several perforations 106 in the ridge zone of the upper tray. Fig. 2 is a detailed illustration of the edges 202 of the upper tray. In this embodiment, the edges 202 of the upper tray are rounded for patient comfort.

[00020] An exemplary embodiment of the lower tray 300 is shown in Fig. 3. The lower tray has two parts: a ridge zone 302 and a bridge 304. The bridge 304 has a perforation 306 that is configured to accept a pin through a threading mechanism. In this embodiment, the edges 308 of the lower tray are rounded for patient comfort. The lower tray 300 has an indentation 310 that is configured to detect if the tray tilts up during the process. There are also several perforations 312 in the ridge zone of the lower tray.

[00021] An exemplary embodiment of the pin 400 is shown in Fig. 4. The upper part 402 of the pin faces the upper tray, while the lower part 404 of the pin is screwed into the perforation 306 in the bridge 304 of the lower tray 300.

[00022] Certain embodiments of the invention provide for a kit that comprises the upper tray, the lower tray, and one or more suitable connectors, such as a pin. Certain embodiments of the invention provide for a kit that includes (a) the apparatus including the upper tray, the lower tray, and one or more suitable connectors, such as a pin, and (b) one or more of the materials required to capture a record such as impression materials and registration materials. The terms-"upper tray" and "lower tray" are relative and does not mean that the upper tray is always above the lower tray; it is possible to use the lower tray for taking impression of the maxillary ridge and the upper tray for the mandible ridge. [00023] Also described herein is a method of making impression molds for dentures using an embodiment of the apparatus as described herein. The method includes first making an impression of the upper ridge using upper tray. Impression materials, like polyvinylsiloxane, are dispersed in the ridge zone of the impression trays. The dental professional provides instructions regarding proper aligning or positioning of the tray in the oral cavity, such as placing the tray as posteriorly as possible or requesting the patient to hold the tray with equal pressure on the right and left side at the bicuspid area, so as to maintain the platform as level as possible. The dental professional holds the tray until the impression material sets and an impression is produced. Then the tray is removed. The process is repeated using the lower tray to obtain an impression of the lower ridge of the patient.

[00024] Tracing of the arch is performed using upper tray using the Gothic Arc tracing method, specifically the active method. The pin in the lower tray is used to secure the trays. The proper vertical dimension for the particular patient is determined using one of a variety of measuring devices including but not limited to a caliper, a ruler, or scriber with a lock. The internal vertical dimension is compared to the predetermined external measurement.

[00025] The dental professional helps the patient move the lower arch with the tray in to the left and then to the right, then forward and backward to get comfortable for the tracing process. Tracing process is the determination of the relationship between the upper and lower jaws. Then the upper and lower trays are removed. The platform of the upper tray is coated with marking material like paint, graphite, crayon, articulating paper, or otherwise recordable substance. The entire apparatus is placed back into the mouth of the patient. The patient is then asked to move the jaws forward and backward, and left and right as previously practiced. This repetitive movement of the jaw results in the tracing pattern being captured on the marking material in the upper tray. The tray is then removed to interpret the results.

[00026] From the tracing results, the dental professional makes an indentation in the upper tray to accommodate the pin from the lower tray, at the location where the three lines cross on the tracings or at the position determinative of the correct centric relation. The upper and lower trays are assembled back and placed into the oral cavity of the patient. Once patient closes her mouth and finds the indentation, then the patient is instructed to hold in that position. The dental professional checks to see if there is any AP rotation present. If not, then the bite registration material is injected to fill in the void between the trays, thus locking the upper and lower tray and creating the record. If AP rotation is present, then the dental professional can correct that by stabilizing the tray with his/her hand and injecting the bite material to capture the record. Once the bite registration material sets, the dental professional is able to get a record that is removed and sent to the lab for fabricating the dentures. Vertical dimension, centric relation, midline, lip line, smile and position of maxillary two central teeth are recorded using the apparatus described herein, thus creating the bite record. The tooth shade and mold are selected. These records are sent to the lab for denture fabrication in wax, which takes about five to ten working days.

[00027] Using an embodiment of the apparatus as described above, the dental professional has full control for centric relation recording. Moreover, patient-induced errors are reduced during centric relation recording. Use of this apparatus causes no protrusion of the lips so the dental professional can determine a more accurate vertical dimension. There is no wax to cut down or add more for altering the vertical dimension— this is done by simply adjusting the pin up or down. The dental professional could optionally place two maxillary centrals (the first two larger teeth in the center of the maxillary arch) for patient to see teeth position, lip line, and midline instead of just placing markings on impression. Use of this apparatus also eliminates the use of the lab to make bite blocks thus eliminating at least one patient visit. Use of this apparatus minimizes need for retries and thus cuts on number of patient visits to the dental office.

[00028] During the second visit, the dental professional fits the patient with wax dentures, and evaluates the patient's comfort level, the dentures' fit in the oral cavity for aesthetics, function, and phonetics and for patient approval. If changes are needed, a new bite is taken with instructions to the lab of the required changes. This step is repeated until dentures are made to fit satisfactorily and use of this new apparatus decreases the likelihood of any repeats for fitting. After a satisfactory fit, the laboratory processes the record and creates the dentures in acrylic for final delivery in five to ten working days. The dental professional fits the patient with the final product.

[00029] The preceding description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the following claims and the principles and novel features disclosed herein.

[00030] While various aspects and embodiments have been disclosed, other aspects and embodiments are contemplated. The various aspects and embodiments disclosed are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.