US3561119A - Preformed anterior pontic patterns - Google Patents

Abstract

A PERFORMED ANTERIOR PONTIC PATTERN MADE FROM A SOLID, NONDEFORMABLE PLASTIC MATERIAL AND SHAPED GENERALLY TO CORRESPOND TO THE LINGUAL PORTION OF AN ANTERIOR TOOTH AND HAVING ENGAGING MEANS CONNECTED ON THE FRONT SECTION OF THE PATTERN FOR ENGAGING AND SUPPORTING A LABIAL PORTION OF AN ANTERIOR PONTIC. THE ENGAGING MEANS FOR THE PRE-

FERRED PONTIC PATTERN OF THIS INVENTION IS A BEARING SECTION POSITIONED TRANSVERSELY TO THE LINGUAL SIDE THEREOF AND CARRYING A PAIR OF INTEGRAL RETAINING PINS WHICH ARE ANGLED TOWARD THE INCISAL TIP OF THE PONTIC.

Description

Feb. 9,1971 H. SUSMAN ETAL 3,561,119

PREFORMED ANTERIOR PONTIC PATTERNS Filed Feb. 24, 1969 4 FIG. 8

INVENTORS: HARRY SUSMAN JON E. SUSMAN 7W,% MM

ATTORNEY United States Patent 3,561,119 PREFORMED ANTERIOR PONTIC PATTERNS Harry Susman and Jon E. Susman, both of 6439 Prestonshire, Dallas, Tex. 75225 Continuation-impart of application Ser. No. 566,157, July 18, 1966. This application Feb. 24, 1969, Ser. No. 801,512

Int. Cl. A61c 13/00 US. Cl. 322 3 Claims ABSTRACT OF THE DISCLOSURE A preformed anterior pontic pattern made from a solid, nondeformable plastic material and shaped generally to correspond to the lingual portion of an anterior tooth and having engaging means connected on the front section of the pattern for engaging and supporting a labial portion of an anterior pontic. The engaging means for the preferred pontic pattern of this invention is a bearing section positioned transversely to the lingual side thereof and carrying a pair of integral retaining pins which are angled toward the incisal tip of the pontic.

This invention is a continuation-in-part of copending US. patent application Ser. No. 566,157, filed July 18, 1966 and now US. Pat. No. 3,457,644 issued July 29, 1969.

This invention relates to performed pontic patterns. In a specific aspect, this invention relates to an improved anterior pontic pattern.

Pontics, i.e., artificial teeth which replace missing teeth, are so widely employed in the art of dentistry as to require no description as to their purpose and general structure. Various methods have been used to make pontics in the past.

Most prior art methods of making anterior pontics have utilized wax. These processes are cumbersome and have proved to be quite difficult when making high-strength anterior pontics of proper shape which truly fit the mouth.

Additionally, the aesthetic qualities of anterior pontics are of paramount consideration. Therefore, not only must an anterior pontic be of high strength and properly fit, but it must have a natural or nonartificial appearance.

Conventional crown and bridge pontics have generally been unsatisfactory because of their physical weakness and artificial appearance. For example, not only are these pontics subject to breakage problems, but under fluorescent and other artificial lighting, many of these conventional pontics have a grayish cast and a decided artificial appearance.

Because of these problems, various veneer-type anterior restorations have been developed. However, most processes which have been developed for producing these veneer-type restorations are more expensive and time consuming than conventional crown and bridge work which utilizes the factory-made pontics.

Various facings are available which can be used by the highly skilled dentist to make veneer teeth. These facings can be utilized to yield better anterior restorations than can be produced with the conventional crown and bridge artificial teeth. However, the processes for making veneer teeth with these facings are generally quite time consuming, and many times yield a rather low quality pontic. For

example, a sheetlike plastic member with a single extending ridge has been utilized in combination with wax and a labial pontic portion for making an anterior pontic. This is not only a tedious process, but the end product is often lacking in integrity of shape, has a poor appearance, and does not fit the mouth of the patient properly. Moreover, the gold casting which ultimately takes the place of ice the wax and the plastic backing has a tendency to fracture or break along its connection with the labial pontic portion, or the labial pontic portion often breaks at the points of high stress where it engages the interconnecting ridge member of the gold casting.

Additionally, various pin facing techniques have been developed which generally utilize a facing or labial pontic portion in combination with connecting pins and wax. The casting, fitting and drilling procedures which are necessary to produce a high quality veneer pontic by these procedures requires unusual technical ability, and the processes are generally very time consuming.

Additionally, the connections between the gold casting and the labial facing in most conventional veneer teeth are weakened with usage. This can result in slight separations between the facing and gold casting which allow entry of fluids and particulate matter from the patients mouth and thereby yield a very unsanitary condition.

Thus, these prior art techniques of producing a veneer anterior pontic with a facing in combination with a molding wax generally require unusual technical ability, and often result in an end product which does not fit properly and is weak at points of high stress where the resulting gold casting is attached to the plastic facing.

Therefore, one obect of this invention is to materially simplify the making of high quality anterior pontics.

Another object of this invention is to provide preformed anterior pontic patterns which make it possible to form high quality pontics by a relatively simple procedure.

A further object of this invention is to provide a preformed anterior pontic pattern which will result in a more sanitary condition for the patient as a result of the pontic ultimately formed from the pattern.

According to the invention, a preformed plastic anterior pontic pattern is provided which is shaped generally to correspond to the lingual portion of an anterior tooth and has engaging means for supporting a labial portion of an anterior pontic disposed on the front section thereof. The pattern is made from a plastic material which oxidizes under oxidation conditions to leave substantially no residue, which has structural integrity at room and body temperatures and will not distort upon handling.

According to a preferred embodiment, the front section of the pontic pattern carries a bearing section which is generally positioned transverse to the lingual side and has integrally molded pin means etxending from the bearing section in the direction of the incisal tip of the pontic. The labial pontic facing has a bearing surface carrying sockets which cooperate with the bearing surface and pins of the pontic pattern. In the most preferred embodiment, the front section of the anterior pontic pattern carries seating means on its periphery adjacent the sides and incisal tip which match and cooperate in an interfitted relationship with seating means on the labial anterior pontic facing. This design will inhibit fluids and the like, within the patients mouth, from working between the ultimate gold casting and the labial pontic facing.

In another but lesser preferred embodiment, the engaging means for the anterior pontic pattern comprises a widened post member extending forward from the front face of the pontic pattern. The post member terminates in an enlarged flange portion which extends outwardly from either side of the post in the vicinity of the base of the pontic pattern. Preferably the post is undercut somewhat so that it engages a mating part in a manner that prevents motion or movement between the two in all directions except axially of the post.

For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of the preferred preformed anterior pontic pattern of this invention;

FIG. 2 is a perspective view of a pontic facing which is adapted to cooperate with the pontic pattern of FIG. 1;

FIGS. 3a-3e are sectional views which illustrate how the pontic pattern of FIG. 1 can be used to manufacture a high quality pontic;

FIG. 4 is a perspective view showing anterior pontic patterns of this invention joined to adjacent crown pat terns for the purpose of providing a pontic pattern unit which may be fit directly into a patients mouth;

FIG. 5 is a side elevation view illustrating another preformed anterior pontic pattern of this invent-ion;

FIG. 6 is a rear elevation view of the labial pontic facing which mates with the anterior pontic pattern of FIG. 5;

FIG. 7 is a side view of an anterior pontic which has been manufactured from the anterior pontic pattern of FIG. 5 and which includes the labial pontic facing illustrated in FIG. 6 as a part thereof; and

FIG. 8 is a cross section taken through 88 of FIG. 7.

Now referring to FIG. 1, preformed pontic pattern 10 is made of a plastic material which can be oxidized to leave substantially no residue. This is important since ultimately a gold casting will be made by the investing casting method utilized in the pontic pattern. Additionally, the plastic material is a material which has structural integrity at room and body temperatures and will not distort upon handling. This will assure that no distortions of the pontic pattern will occur while it is being manipulated by the dentist or dental technician during the fitting or molding process.

Pontic pattern 10 generally corresponds to the shape of a lingual portion of an anterior tooth from its base 11 to its incisal tip 12. The front section of pontic 10 comprises a recessed front face 13 which extends generally parallel to the lingual surface, seating sections 14 which extend from the front portion of the sides 15 and incisal tip 12 inwardly to the periphery of face 13, and bearing section 16 which extends inwardly from the front portion of base 11 to face 13 and carries a pair of parallel integrally molded pins 17 thereon. Pins 17 generally extend in a direction toward incisal tip 12. It is generally preferred that pins 17 extend at an angle of 90 degrees from bearing section 16 to form a 45 degree angle with face 13.

Now referring to FIG. 2, the rear portion of labial pontic facing 19 is illustrated in detail. Facing 19 can be made of any suitable pontic material, such as a porcelain or plastic material, for example, material used in the manufacture of anterior denture teeth. As illustrated, seating sections 14' and bearing section 16' are shaped to match seating section 14, and bearing section 16, respectively. Holes 17' are positioned on bearing section 16' and are adapted to receive pins 17. Thus, when labial facing 19 is positioned in engaging relationship with preformed anterior pontic pattern 10, seating sections 14' of pontic facing 19 will rest against seating sections 14 of preformed pontic pattern 10 and thereby allow surface 13' of anterior facing 19 to rest against front face 13 of preformed pontic 10. In like manner, bearing section 16' of pontic facing 19 will match with and rest against bearing section 16 of pontic pattern 10, and pins 17 will thereby extend within holes 17. It is to be noted that the number of pins 17 is not critical; however, it is generally preferred that bearing section 16 carry a pair of parallel pins as illustrated in FIG. 1 to thereby prevent movement between pontic pattern 10 and anterior pontic facing 19 in all directions except axially of pins 17. The cooperating action of seating sections 14 and 14' not only further induce a stabilized engagement between pontic pattern 10 and anterior pontic facing 19, but provide an interfitting relationship between these members which will ultimately yield a more sanitary condition for the patient as a result of the pontic ultimately formed from the pattern.

4 Thus, it will be very difiicult for fluids and particulate matter to work their way between a pontic facing and the pontic backing of the resulting laminated pontic.

In using pontic pattern 10, anterior pontic facing 19 is initially coupled thereto to form an integral pontic pattern. As shown in FIG. 3a, the integral pontic pattern is positioned adjacent gum ridge 20 (as seen from the side in section) and an observation is made by the dentist to determine whether the arch of the pattern roughly corresponds to the gum ridge. If it does not, plastic is ground off or otherwise removed from the base of pontic pattern 10 and upper exposed base area 22 of anterior ponti facing 19 to steepen the arch region of the integral pontic pattern and bring it into closer conformity with the gum ridge. The integral pontic pattern is illustrated in FIG. 311 after the arch has been shaped, as discussed.

A viscous formable material, such as methyl methacrylate plastic is next painted over the ridge adjacent pontic pattern 10 to form plastic layer 21. A release agent, such as petrolatum, or liquid foil or the like, is lightly applied over gum ridge 20 and the upper exposed base area 22 of anterior pontic facing 19 before applying the viscous material to facilitate a later release.

Next, the curved base of the integrated pontic pattern is applied to gum ridge 20, and pontic pattern 10 is firmly emplaced on layer 21 after layer 21 has cured somewhat. This step is illustrated in FIG. 31:. Pontic pattern 10 and the plastic layer 21 are allowed to remain in such contact until the layer 21 fuses to the pontic pattern 10 and becomes an integral part thereof. At that time, the plastic layer 21 is substantially cured to form a solid or hardened plastic material.

After fusion and hardening is completed, the pontic pattern is removed from the articulated model, the removal preferably being facilitated by a thin film or release agent, such as liquid foil or petrolatum as previously referred to herein. If necessary, a small amount of grinding removes any portions of the bonded layer which are not desired, such as regions of the applied viscous material which fiowed further down on the gum ridge than necessary. The finished pontic pattern and facing, after processing on the articulated model, as described above, is illustrated in FIG. 3d.

The processed preformed plastic pontic 10 of FIG. 3d is thereafter used in an investment casting process by which an investment mold is made. The plastic material is burned-out, i.e., oxidized, by heating under oxidizing conditions. Finally gold is introduced into the investment mold to cast the pontic, which has the same configuration as the investment mold.

The gold pontic is emplaced on the articulated model and joined to adjacent crowns by processes well-known in the art of dentistry. The gold pontic is joined to facing 19 to form anterior pontic 23 as illustrated in FIG. 3e.

In some instances, the pontic pattern 10 will not have sufficient width to properly mate with adjacent teeth to form a high quality pontic. This can be remedied by painting on or otherwise applying a quantity of viscous formable material on the sides 15 of the pontic pattern while it is in position on an articulated model of the patients tooth structure.

Sometimes it is desirable to make a fitting in the patients month during the course of processing a pontic in accordance with the present invention. This may be accomplished by actually fitting a preformed pontic pattern into a patients mouth after the pontic pattern has been joined to adjacent crown patterns. This technique is illustrated in FIG. 4, wherein plastic crown patterns 41 and 43 are disposed on an articulated model to overlie the model crown preparations 41' and 43', respectively. Plastic crown patterns 41 and 43 may be made of various plastic materials, e.g. of polymethylmethacrylate. The crown patterns 41 and 43 are joined to two preformed pontic patterns, such as the pattern 10 previously discussed in connection with FIGURES 1-3, by means of a viscous formable material, e.g., polymethylmethacrylate carried by methyl methacrylate monomer. Thus, viscous liquid plastic forming material is applied to form joints 45, which join sides 15 of preformed pontic patterns 10 to one another and to respective adjacent crown patterns 41 and 4-3 as illustrated in FIG. 4. After the applied viscous material cures, the crown patterns 41 and 43 and the preformed pontic patterns 10 of FIG. 4 form a single unit which may then be tried in the patients mouth to verify the integrity of the fit. Thereafter, the joined crownpontic pattern unit is utilized as an integral pattern in an investment casting process. The product is a gold casting Which conforms to the shape of the integral pattern. Labial pontic facings 19 can next be aflixed to the two anterior pontic portions as illustrated and discussed in conjunction with FIG. 30. Pontic facings can be applied to crown patterns 41 and 43 by conventional processes.

Now referring to FIG. 5, an alternative anterior pontic pattern 51 is illustrated. This pattern is preferably of plastic and shaped generally as the rear or lingual half of an anterior tooth. Its front or labial face 52 has a widened post portion 53 extending forwardly therefrom. The post portion 53 is undercut on both sides, as is indicated at 54 and 55 (FIGS. and 8). Flange portions 57 extend from either side of post portion 53 at its base end and connect with the labial face 52 of lingual pattern 51. Such flanges provide a region for seating, and also strengthen the post portion 53 somewhat.

The pontic pattern 51 is emplaced on an articulated model and processed generally in accordance with the steps illustrated in FIGS. 3a-3d as previously explained herein. A gold pontic portion is then made by the investment casting process to conform to the shape of the plastic pontic portion 51. This product is identified in FIG. 7 by the numeral 41. To it a porcelain or plastic labial pontic portion 61 is attached. As is best seen in FIG. 6, labial pontic portion 61 has on its lingual or rear face a recessed region 63 shaped to mate precisely with the post member 53 and flange members 57, the undercut portions 54 and 55 of post 53 being engageable with grooves 54' and 55' (note dotted lines in FIG. 6) and flange portions 57 being engageable with flange seats 57 on labial pontic portion The pontic of FIG. 7 is a high quality product which is then emplaced in the mouth of the patient by conventional processes which are known in the art of dentistry.

Various plastic materials may be used for the preformed pontic pattern of the present invention, the preferred material being polymethylmethacrylate. Moreover, the viscous formable material used in conjunction with the pontic pattern to precisely fit the ridge and, if desired, to widen or otherwise alter the pattern or join it to adjacent patterns to form a unitary structure, may likewise be selected from a wide variety of plastic materials, the preferred material formed by the hardened viscous formable material again being polymethylmethacrylate or a copolymer of the same. Exemplary of specific materials satisfactory for forming a preformed pontic pattern in accordance with the present invention, as well as for serving as the viscous formable material utilized in the practice of the present invention are the following:

(a) Duralay powder 1057N and liquid 1151N, marketed through Reliance Dental Manufacturing Company, Chicago, 111.

(b) Langs Resincap, marketed through Langs Company, 900 N. Franklin St., Chicago, Ill.

(0) Myersons Self-Curing Crown and Bridge Resin, cross-linked copolymer, and Myersons cross-linked monomer for Myersons Crown and Bridge Resin, marketed by Myersons Tooth Corporation, Cambridge, Mass.

((1) Rimseal powder and Rimseal liquid, marketed by Harry I. Bosworth Co., Chicago, Ill.

To generalize regarding the preferred available commercial preparations, they usually are powdered acrylic resins, e.g., polymethylmethacrylate, used in conjunction with an acrylic monomer, e.g., methyl methacrylate monomer, to form a liquid material which is self-curing at room temperature. During the curing process, the liquid becomes increasingly viscous, until finally solid acrylic plastic results. While the precise compositions of the various commercially available materials are not known, the various powders available are often polymethylmethacrylate and contain a small quantity of catalyst such as benzoyl peroxide or diisobutylazonitrile. The liquid material used therewith is principally methyl methacrylate monomer, and generally contains an inhibitor, such as hydroquinone, and a chemical accelerator, such as an organic tertiary amine, e.g., dimethyl-para-toluidine, or a sulfinic acid.

Some preferred materials commercially available include a copolymer of methyl methacrylate and another monomer. For example, the copolymer may be ethyl or butyl methacrylate, together with methyl methacrylate.

While polymethylmethacrylates and related plastics are preferred, any material may be utilized as a material of construction for the preformed pontic pattern of the present invention provided that it forms a solid having structural integrity at room and body temperatures such that the material will not distort or loose shape upon being manipulated by a dentist or technician, provided that it burns-out during the course of the casting process, and provided that it is capable of achieving a smooth surface. Moreover, any material may be utilized for the viscous formable material employed provided that it has the qualities referred to in the foregoing sentence, and in addition, that will adhere to the preformed pontic pattern. Also, it is distinctly preferred that the viscous formable material be cold curing, or at least curable at a temperature not far above room temperature.

Having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest themselves to those skilled in the art and it is intended to cover such modifications as fall within the scope of the appended claims.

We claim:

1. A preformed plastic pontic pattern, said plastic being of the type which has structural integrity at room and body temperatures, will not distort upon handling, and that when oxidized under oxidizing conditions will leave substantially no residue, said pattern being shaped generally to correspond to the lingual portion of an anterior tooth, from base to incisal tip, and having a front section comprising a front face which is positioned general- 1y parallel to the lingual side thereof, recessed, and thereby enclosed by inwardly directed seating sections extend ing from the sides and incisal tip of said pontic pattern, and a bearing section extending inwardly from said base, and aligning and engaging pin means extendin from said bearing section and directed generally toward said incisal tip.

2. The preformed pontic pattern of claim 1 wherein said aligning and engaging pin means comprises a pair of parallel integrally molded plastic pins.

3. The preformed plastic pontic pattern of claim 2 further comprising a labial pontic facing having a rear section adapted to mate with the front section of a lingual pontic portion cast from said lingual pontic pattern portion.

References Cited UNITED STATES PATENTS ROBERT PESHOCK, Primary Examiner

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