Dental tray spacer

A convenient dental tray spacer for use in forming a thin reservoir space between teeth and a dental tray, during tray fabrication. Shim (10) segments are connected by small links (12) to form a spacer (16). The lengths of the links are readily variable. Retention to the teeth is provided by adhesive on rear adhesive surfaces (22). Alternatively, an elastic loop (24) can retain a spacer (16′). Spacer (16), or spacer (16′), remain on the teeth while the dental tray is formed, and then is pulled free from inside the formed dental trays.

BACKGROUND—FIELD OF THE INVENTION

This invention relates to medicine and dentistry, specifically to an improved method and apparatus for fabricating custom dental treatment trays for applying treatment agents to the teeth and/or gingiva.

BACKGROUND—DESCRIPTION OF PRIOR ART

Custom dental treatment trays are used to hold tooth whitening or bleaching gels, fluoride, topical anesthetics, antibiotics, antihistamines, medications, and other such treatment agents, closely against the surfaces of the teeth and/or gingiva for extended times. Dental trays typically are made by tightly suctioning softened elastomeric sheets of stock tray material onto plaster models of the patient's dental arches. Excess tray material is then trimmed away to achieve the desired tray shape. Dental trays are most effective when fabricated with slight spacing created between the surfaces of the teeth and the tray material. This provides room, or a reservoir, for the treatment agents. Without a reservoir space, the tray material itself tightly contacts the broad surfaces of the teeth, and the treatment agents tend to be displaced. When this occurs, the beneficial effects of the treatment agents are reduced, and the treatment time, the amount of treatment agents required, and irritational side effects are increased.

There is a problem with creating the reservoir space under the dental trays, however, and that is the considerable time it requires for dental personnel. Cost is also a factor for some techniques.

The most widely used dental tray spacing technique involves manually painting a liquid spacer material, such as thick fingernail polish, onto the appropriate areas of the patient's teeth, or models of their teeth, prior to forming the trays. The depth of the paint itself forms the tray space. Typically, only one coat is painted on, although this forms a relatively thin space, and it must be allowed to dry before the dental tray may be fabricated. A border area around the circumference of the tooth remains unspaced, in order to seal off the reservoir area from saliva, and to retain the treatment agent. The first disadvantage to this technique is that several minutes are required to apply one coat of spacer paint, plus about twenty minutes for drying. The second disadvantage is that multiple coats are needed to achieve an ideal thickness for the reservoir space. Since that would require excessive time, a minimally adequate reservoir depth from just one coat is usually tolerated as better than none. A third disadvantage is that the thin spacing is not readily apparent when inspecting the tray visually. Thus the dentist or patient, who is to purchase the spaced dental tray, must rely on the word of the maker that is was actually spaced. This is a disincentive for laboratory and dental personnel to accept the inconvenience and cost of properly spacing the dental trays.

A similar technique involves manually painting viscous light-cured spacing resin over the teeth surfaces, instead of fingernail polish. Again, it is not applied to the border area, so that a seal may be created for retaining the treatment agent over the treatment surface, and to seal out saliva. It creates a more ideal thickness of reservoir space with a single coat. However, it still has the disadvantage ofrequitingrequiringseveral minutes to paint on the teeth. Then, the resin is hardened with two minutes exposure to a special curing lamp. Another disadvantage is the considerable cost of the special curing lamp apparatus. To avoid that expense, many dentists cure with their existing intraoral curing lamps instead. Unfortunately, these require a twenty to forty second exposure time per tooth, which more than doubles the time required to cure the resin spacing medium, and these lamps have higher operational costs. The light-cured resin itself is also costly.

Another technique involves molding clay-like material onto the surfaces of the teeth. Again, the border seal area is left unspaced. This technique requires some sculpting skill, and still greater application time. It is not commonly used.

Another technique, described as the primary embodiment in U.S. Pat. No. 5,356,291 to Darnell (1994), involves covering the entire inner surface of the tray with a sheet of open or closed cell foam, or a sheet of fibrous absorbent material. This does not create an effective border seal, so it is somewhat ineffective in retaining and restricting the treatment agent to the area immediately over the teeth. Instead, the treatment agent is permitted to dissipate in concentration and effectiveness over the treatment surfaces, while saliva increasingly soaks into its place. At the same time, the treatment agent may flow out over the gingiva or root areas, where it may cause irritation. This is especially true for tooth bleaching gels. A second disadvantage is that the foam or fiber quickly accumulates heavy bacteria plaque and debris, and begins to look and smell badly. Repeated cleaning the foam or fiber tends to destroy it, as it is somewhat fragile. The foam or fiber also deteriorates and oxidizes more quickly than the dental tray material that backs it.

A secondary embodiment of Darnell (1994) utilizes foam or fiber material segments to act as treatment agent reservoirs between the tray and individual teeth. The disadvantage is that the construction is tedious, and the resulting tray is difficult to clean. Darnell does not teach removable shims for dental tray spacing.

A tertiary embodiment of Darnell (1994) involves creating the space between the dental tray and the teeth by abrading or sandblasting away some of the inner surface dental tray material from the formed dental tray. The disadvantages of this technique are that costly sandblasting apparatus is required, that skillful, highly attentive workmanship is required to accurately cut away dental tray material, and that the dental tray material is somewhat weakened over the indentation/reservoir site. Thicker, less comfortable, tray material is required, than for techniques which do not thin the tray.

Another technique, reported in U.S. Pat. No. 5,326,685 to Gaglio et al. (1994), utilizes an impervious flexible backing material over an open-cell foam, to create a reservoir for treatment agents. An additional reservoir is formed by sealing the borders of the foam to the backing material, thus creating a space between them. Disadvantages of this technique include complex fabrication, additional steps being required to load treatment agents into the reservoir spaces, the inability to seal the treatment surfaces from saliva, the inability to seal or restrict the treatment agents to the treatment surfaces, and difficulty cleaning the open cell foam.

Millions of dental trays are currently in use, most for bleaching teeth. Many are fabricated without spacing built in at all, because of the cost and inconvenience to the dental personnel to make spaced trays. But unspaced dental trays waste the time and money of patients who attempt to utilize them. The resilient dental tray material squeezes the treatment agents away from the desired location, reducing the effectiveness and efficiency. Bleaching sessions typically last several hours of time, and the bleaching agents are costly. The process is further undetermined because the displaced bleach increasingly contacts, and may irritate, the gingiva and root areas of the teeth.

A dental tray spacer has not been produced to date because it is not obvious how to connect shim segments for convenient mounting on the wide variety of dental arches, with their differences in distances between tooth centers, tooth sizes, shapes, misalignments, gaps and rotations.

OBJECTS AND ADVANTAGES

Accordingly, several objects and advantages of the present invention are:

(a) to provide an improved method for forming reservoir spaces under dental trays, for treating teeth with treatment agents, which produces results which are superior to the results heretofore known to the art;

(b) to provide a spacer comprising multiple connected shims, each of which mount on individual teeth, such that several teeth of a dental arch of teeth may be quickly shimmed with a single spacer;

(c) to provide a spacer which is shaped to form adequate reservoir spaces under dental trays, as the trays are formed, wherein such spaces can readily receive and hold treatment agents;

(d) to provide a spacer shaped to substantially cover surfaces of teeth, leaving a circumferential area of the tooth surface uncovered, and unspaced, such that the formed tray rests directly against the circumference of the tooth, thus enclosing a central, spaced, reservoir area which can retain treatment agents, while restricting oral fluids from treated tooth surfaces;

(e) to provide a spacer which is somewhat deformable, to compensate for variations in the size, shape and spacing between individual teeth of a dental arch;

(f) to provide a spacer comprising multiple shims connected by links of variable effective length, such that the distance between individual shims is similarly variable;

(g) to provide a spacer whose tray spacing will be visually apparent, to assure the purchaser of the formed dental tray;

(h) to provide a spacer that creates accessible, cleanable reservoir spaces in formed dental trays, such that bacterial plaque and debris are not readily harbored;

(i) to provide a spacer that creates reservoir surfaces in the formed dental trays that do not deteriorate quickly, such as by tearing or oxidation of materials.

Further objects are to provide a spacer that requires minimal time and skill to mount to relevant surfaces of the teeth or dental models, and is economical to use. The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the invention. Accordingly further objects, advantages and understanding of the invention may be had by referring to the summary of the invention, and the detailed description, in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.

REFERENCE NUMERALS IN DRAWINGS10SHIM

12′ elastic link

SUMMARY

A Dental Tray Spacer is a linked strand of multiple tooth shims for mounting on the surfaces of teeth, or replicas of teeth. The shims cause a reservoir space to form between dental trays and the oral structures, during the fabrication of the dental trays. It should be appreciated by those skilled in the art that the conception and specifics disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart form the spirit and scope of the invention as set forth in the appended claims.

DESCRIPTION OF INVENTION—FIGS.1TO6

FIG. 1shows an elevational view of a preferred embodiment of my dental tray spacer. Individual spacer tooth shim elements, shims10, are provided in a flat, connected strip, spacer16. Shims10are connected to form spacer16by links12. For spacer16, the first shim10is connected to the first link12. The first link12is connected to the second shim10. The second shim10is connected to the third link12, and so on, through the final shim10. The number of shims10shown in spacer16is typical. However, there could be more, or fewer, shims10. Spacer16is supplied mounted on a backing sheet, backing14.

The circumference form, or circumferential shape, of each shim10approximates the circumferential shape of the corresponding, respective, tooth upon which it is to be mounted. For example, the shim10which is to mounted on the surface of the canine tooth has a circumferential shape somewhat resembling that of a canine tooth. The sequential order of the variously shaped shims10along spacer16, corresponds with the typical sequence of teeth. Such sequential grouping of spacers10by size and shape makes spacers16convenient. However, shims10can have a universal circumferential shape, such as an ovoid shape. A selection of sizes enhances the likelihood of adequate coverage of the tooth surfaces. The circumferences of shims10are substantially in the plane of the spacer16strip.

Generally, the shim10circumference will be just slightly smaller than the circumference of the tooth upon which it is to be applied. Thus, a small circumferential area of the tooth surface bordering shim10remains uncovered, and unspaced. A dental tray formed over such unspaced circumferential tooth surfaces would rest directly against the circumferential surfaces of the tooth. This creates a sealing effect, enclosing a central, spaced, reservoir area which can retain treatment agents. Similarly, the movement of oral fluids into the circumferential area is somewhat restricted. If unspaced border areas are small, then treatment agents from the spaced dental tray reservoir, will feed to the border adequately enough to treat the border area.

The material from which shims10are fabricated is pliable and deformable. Pliability of shims10facilitates conforming to the surface contours of the respective mounting teeth. It is preferable that the material also be sufficiently deformable to permit slightly altering the dimensions by pushing the material over the tooth surface. The material may be adequately deformable at room temperature, or its pliability may be increased by heating, or by treating with a solvent. A number of pliable materials are effective. The material cuts readily with scissors or blades to facilitate trimming down the shape where indicated.

Links12are connected between shims10to facilitate mounting on the teeth. It is preferred that links12are comprised of tough, flexible material, continuous with the material of shims10. However, links12may be manufactured from different material than that used for shims10. Links12are of sufficient strength so as to resist inadvertent rupture during routine mounting procedures.

The length of links12is sufficient to permit mounting any two linked shims10on adjacent, ideally aligned, teeth. Ideally aligned teeth contact one another in the interproximal areas, and theplaneplanesof the facial surfaces of the teeth are substantially tangential to the curvature of the dental arch. The length of links12required for connected mounting of shims10on ideally aligned teeth, is a minimal length.

In the preferred embodiment, the length of links12is further sufficient for mounting connected shims10on substantially misaligned teeth. Misaligned teeth have gaps, tipping, and rotations, which increase the minimal link12length required for mounting shims10. As such, links12are of greater length than required for mounting on ideally aligned teeth.

When mounting spacer16on substantially aligned teeth, there remains an unutilized portion of the length of links12. To prevent inadvertent entanglement, such unutilized length portions of links12are weakly connected adjacent to some spacer16structure by a separable connection means. The separable connection positions such unutilized lengths of links12out of the way of the operator, in reserve. The separable connection is of sufficient strength so as to resist inadvertent separation during routine mounting procedures.

The separate connection is sufficiently weak such that purposeful separation of shims10can separate the separable connection without rupture of other spacer16structures, such as when mounting links12on misaligned teeth. When the separable connection is separated, the utilized length of links12is effectively increased. The unutilized length of links12can be considered to be effectively decreased, proportionally. As such, adjacent shims10thereby remain connected while mounted on teeth with greater, or increased, separation distance. The effective length of links12can therefore be considered to be variable.

In the preferred embodiment, the separable connection is a thin membrane of shim10material. The thin membrane is weak enough to be purposely torn, but is sufficiently strong to remain intact during routine mounting of spacer16.

In the preferred embodiment, the separable connection connects the unutilized length portions of links12to shim10. Each link12is configured in a bow which point toward the incisal edges of the teeth. However, links12may be configured in a bow which point toward the gingival border of the teeth. The unutilized length portions of links12are oriented somewhat incisally to gingivally, along the lateral border of shims10. The utilizable length portion of the link12has a substantial mesial to distal orientation, and is located at the apex of the link12bow.

Although they are of narrow width relative to shims10, links12have distinctive cross-sectional shapes to minimize entrapment in a formed dental tray. Preferred shapes would be those with carved surfaces, such as cylindrical or ovoid. However, when the rear surfaces of the links are angular or flattened, it is preferable that they exhibit adhesive properties. Thus, they could be pressed into the embrasure crevice, and adhered to the teeth, out of the way of a forming dental tray.

FIG. 2shows a perspective view of spacer16mounted on a dental arch model, model18, ready for dental tray fabrication. However, for intraoral dental tray fabrication techniques, spacer16would be mounted on a patient's actual teeth, intraorally. Uncovered circumferential areas are apparent about shims10.

FIG. 3shows a perspective view of an alternative dental tray spacer, a spacer worm20, as supplied on backing14. Spacer worm20is a continuous spacer strip, whose height is preformed in sizes that approximate the heights of teeth, whose thickness is preformed to create an adequate reservoir space, and whose spacer portions over teeth surfaces are connected continuously by broad linking areas between the teeth, with both spacer areas and link areas having the same height. Spacer worm20and backing14may be supplied wound on a spool of indefinite length, to be cut to the appropriate length.

FIG. 4shows a perspective view of spacer worm20cut to length and in place on dental arch model18, ready for dental tray fabrication. The element of spacer worm20must be more pliable and deformable than spacer16, to facilitate mounting on the teeth. It is sufficiently pliable to press into the embrasure crevice between the teeth, despite the breadth of the linking areas. It is sufficiently deformable to permit altering the height dimension, by pushing the element on the tooth surface, such as in areas adjacent to the gingiva. It may be adequately deformable at room temperature, or the pliability may be increased by heating, or by treating with a solvent.

FIG. 4also shows a perspective view of soft tissue spacer21mounted on a selected site on a model18. Soft tissue spacer21may be mounted anywhere on the gingiva, the gingival margin adjacent to the teeth, or the oral mucosal tissue, that the dental tray can extend. Soft tissue spacer21will typically be provided in symmetrical shapes and sizes. Soft tissue spacer21effectively builds out the surface of the mounting site so that a reservoir space can be created under the forming dental tray. Optional soft tissue spacers21with an outer surface color-transfer dye or decal can be convenient for clearly marking the reservoir location in the formed dental tray.

FIGS. 5Ato5F show selected cross-sectional embodiments of shims10. Cross-sectional shapes shown are5A lens-shaped,5B uniform thickness,5C teardrop,5D corrugated,5E concave, and5F convex. The teardrop, concave, and convex shapes especially facilitate the manual extension of spacer coverage where necessary, such as for longer teeth, or to extend down the root toward the gingiva of teeth where the gums have receded, or for lapping over an incisal edge of a tooth. It is preferred that the depth, or thickness, of any cross-section is less than 1 mm. However, a thickness of 1 mm or greater is also effective. Where possible, spacer16edges are tapered to a sharp acute angle, such that they will adhere flush to the teeth, and minimize surface undercuts. This will minimize locking into the dental tray during its fabrication.

Adhesive Surface22is the surface of spacer16that is to conformably mount onto the teeth. Adhesive Surface22is sufficiently pliable to conform closely to the curved, irregular surfaces of teeth or tissue. It is preferred that adhesive surface22be supplied exhibiting sufficient adhesive properties to retain spacer16on irregular tooth surfaces during the fabrication of the dental tray. However, spacer16may be supplied from the manufacturer without adhesive surface22exhibiting adhesive properties. As such, the user would apply an adhesive, such as a liquid glue, prior to mounting on model18.

The adhesive properties of adhesive surface22are temporarily and reversibly inhibited, such as with backing14, or other means of adhesive inhibition. Such inhibition of adhesive surface22is reversed prior to mounting on model18by removing backing14. However, inhibition of adhesive surface22can be reversed by removing some other protective coating, by heating, by wetting with a solvent, and so on.

FIG. 6shows a perspective view of a spacer16′ retained by an elastic loop, loop24. It is preferred that spacer16′ is not simultaneously retained by loop24and adhesion. However, simultaneous retention with adhesion is effective. Loop24connects the rightmost and leftmostportions orshims10′, behind spacer16′. Loop24retained spacer16′ is substantially configured as a closed loop, rather than a flat strip. The circumferences of shim10′ are substantially perpendicular to the plane of such a spacer16′ loop. Loop24is shown stretched between the posteriormost teeth on opposing sides of the dental arch of model18. Stretched thus, loop24will typically be suspended a distance above the posterior palate. To prevent suspended loop24from becoming locked into a forming dental tray, it is drawn down to the palate by hooking its midpoint on an anchor, loop anchor26. However, other anchoring devices are effective, or the anchor can be eliminated. Loop anchor26is held in its position simply by the weight of model18.

When spacer16′ is retained by loop24, it is preferred that the links be comprised of elastic material, forming elastic links12′. Elastic links12′ may generally be shorter than links12, and do not necessarily bow between teeth. The lengths of unstretched elastic links12′ approximate the distance between borders of shims10′ mounted on ideally aligned teeth. Elastic Links12′ stretch to accommodate correct positioning of shims10′ during mounting on model18. As such, elastic links12′ have a variable length. For misaligned teeth, the variable length is utilized by stretching links12′ across the increased distance between the teeth, to position adjacent connected shims10′.

From the description above, a number of advantages of my dental tray spacer become evident:

(a) Preformed spacers minimize the steps required to form adequate and effective reservoir spaces in formed dental trays.

(b) The spacer can be deformed to compensate for variations in the size, shape and spacing between individual teeth of a dental arch, to facilitate mounting.

(c) The spacer is comprised of multiple shims connected by links with variable effective lengths, such that the distance between individual shims is variable, and may be increased.

(d) Treatment agents are restricted to the reservoir spaces by border seals around the circumferences of the treatment surfaces, and oral fluids are likewise restrained from the treatment surfaces.

(e) Required time and cost is minimized in applying dental tray spacers.

(f) Persons less skilled in dental procedures can apply spacers.

(g) It is visually apparent that the completed dental trays have treatment agent reservoir spaces.

(h) Dental trays formed utilizing the spacers are durable and readily cleanable.

Operation of Invention—FIGS.1to6

Model18is free of artifacts, clean and dried. A spacer16is selected, whose shims10are just slightly smaller than the teeth of model18, to facilitate formation of a circumferential seal. Spacer16is also selected for the most effective cross-sectional shape, shown inFIG. 5, as each shape has unique characteristics for adhering to the teeth. In addition, each shape imparts a unique shape to the subsequently formed reservoir.

Spacer16is removed from adhesive backing strip14, shown in FIG.1. If spacer16is judged to be less pliable than is necessary for mounting, then the pliability may be increased, by exposure to heat, solvent, or such. Spacer16is oriented over the teeth of model18. The first shim10is centered over the respective tooth of corresponding shape and position. Shim10is mounted by pressing onto the tooth surface, such that shim10is conformed to the tooth surface contours. Adhesion of shim10to the tooth is thus maximized. If the second respective tooth is aligned with the first tooth, then the second shim10in sequence, whose shape corresponds to the second tooth, is likewise centered and applied to the surface. The sequence is repeated for the third shim10, and so on. Typically, all shims10are applied to the teeth in less than 30 seconds.

When a shim10is to be applied to an misaligned adjacent tooth, then the utilizable length of the connecting link12is increased by separating the separable connection. The separable connection of the link12is separated by pulling the shim10to be mounted into position over the misaligned tooth. The shim10pulls the connected link12, which in turn separates the separable connection. In the preferred embodiment, the separable membrane connecting link10to shim10is torn away, increasing the utilizable portion of link12.

If adjacent teeth are misaligned severely enough so that a link12will not stretch between the teeth, despite entirely separating the separable connection, then link12can be cut. Links12can also be cut to eliminate sequential shims10, such as at the positions of missing teeth, or to substitute in shims10of different size or shape.

When all shims10are adhered to respective teeth surfaces, all links12are pressed back against the teeth, and between the teeth, so they are out of the way. A mounted spacer16is shown in FIG.2.

Although not necessary for most cases, customizing of shims10is performed after application of spacer16. However, it may be performed prior, or during application. For example, if an individual shim10extends beyond the circumference of an unusually shaped tooth on a certain side, then it may be cut to fit. On the other hand, if there is an unusually wide border area of tooth surface extending beyond shim10, then resin spacer mediums of the art may be added to cover such border areas.

If spacer16′ is retained by loop24, as shown inFIG. 6, then a spacer16′ with a loop24is selected, whose shims10′ are just slightly smaller than the teeth of model18, and which have the most effective cross-sectional shape. Shims10′ are oriented over the teeth of model18. Loop24is stretched around the posterior ends of the posterior teeth, so that it stretches across the opposite sides of the dental arch, above the palate. Loop24is then pulled down to the palatal level, out of the way of forming dental tray material, such as by hooking it on loop anchor26connected to a rear section of the model. Shims10are then centered on each tooth by appropriately stretching elastic links12′.

Following the application of any spacer16, or spacer16′, on model18, a non-stick separating medium is applied to spacer16, or spacer16′, prior to fabrication of a dental tray. The dental tray stock material pliability is increased, such as by heating. When sufficient pliability is attained, the dental tray stock material is quickly positioned and adapted to cover spacer16, or spacer16′, and the teeth, such as over model18. It is preferred that the tray material is made to closely conform to the shape of spacer16, or spacer16′, by applying a strong vacuum to the under-surface of model18.

After the dental tray material is made less pliable, such as by sitting at room temperature a short time, the formed dental tray with excess flashing material, is loosened and removed from model18. If spacer16, or16′, has become embedded in the dental tray, rather than remaining adhered to model18, then it must be gently pried free, to avoid breaking links. Used spacers may be discarded, or sterilized for reuse. The dental tray is completed by trimming away extra dental tray material, and assuring that trimmed edges are smooth.

Conclusion, Ramifications, and Scope of Invention

The dental tray spacer of this invention may be quickly adhered to the individual teeth of most dental arch models, in correct order, and with little or no alteration, so that all spacer shapes fit their respective teeth.

Accordingly, the reader will see that the dental tray spacer of this invention can be used to assure the formation of an adequate reservoir space between dental trays and the teeth, and that this can be done in minimal time, with little cost, and without requiring a high level of skill. Most practitioners currently do not provide reservoir spacing under their treatment agent dental trays during fabrication, primarily due to the time and cost of techniques of the art. An efficient spacing technique, such as this, could translate into saving many hours of patient treatment time. For those practitioners that do utilize spacing techniques of the art, the dental tray spacer can save significant time and money, and their patients can be shown the visible reservoir spacing in their trays as assurance that they are receiving efficient treatment.

While my above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of some of the presently preferred embodiments thereof. Many other variations are possible. For example, from an elevational view, spacer16, or spacer16′, could be comprised of symmetrical, ovoid shaped shims10, rather than tooth shaped. For certain treatments, these would provide adequate reservoir space under the dental tray. Such symmetrical shims10could be supplied in a continuous chain, from which a spacer16, of any desired number of segments, could be cut.

As a second example, spacer16could be applied directly to the patient's actual teeth, for intraoral dental tray fabrication techniques, rather than on model18.