US3478429A - Standardized orthodontic tooth-positioning and retaining device - Google Patents

Description

Nov.18,-1969 D.J.SHiI 'L IDAY 3,478,429

STANDARDIZED ORTHODONTIC TOOTH-POSITIONING AND RETAINING DEVICE Filed May 21, 1968 2 Sheets-Sheet 1 INVENTOK DOUGLAS J. SHILLIDAY BY MAHONEY, MIL R 8 RAMBO BYW ' A TTORNEYS Nov. 18, 1969 I D. J. SHILLIDAY 3,478,429

STANDARDIZED ORTHODONTIC TOOTH-POSITIONING AND RETAINING DEVICE Filed May 21, 1968 2 Sheets-Sheet 2 INVENTOR. DOUGLAS J. SHILLIDAY BY MAHQNEY, MILLER 8 RAMBO A TORNEYS United States Patent O1 fice 3,478,429 Patented Nov. 18, 1969 3,478,429 STANDARDIZED ORTHODONTIC TOOTH-POSI- TIONING AND RETAINING DEVICE Douglas J. Shilliday, Upper Arlington, Ohio (1501 London Drive, Columbus, Ohio 43221) Filed May 21, 1968, Ser. No. 730,716 Int. Cl. A61c 7/00 U.S. Cl. 3214 4 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates generally to orthodontic appliances, and more specifically to a standardized, preformed, tooth-positioning and retaining device intended to be worn on a periodic basis by persons whose teeth have been previously subjected to correction by means of metal bands, arch wires, and the like.

Following correction of teeth by means of the usual metal bands, arch wires, etc., it has been found desirable to provide orthodontic patients with what is commonly referred to as a retainer. One type of retainer in general use comprises a custom-molded, rubber-like mouthpiece which is made from cast impressions of the patients teeth in their corrected positions. These retainers are usually worn by the patient at periodic intervals of privacy, such as while sleeping, for the purpose of holding and supporting the somewhat mobile teeth in their desired, finally corrected positions until the teeth have become stabilized. Typical examples of such retainers are described in prior U.S. patents to Kesling Nos. 2,467,432 and 2,531,222. Still another type of retainer utilizes a rigid, substantially inflexible, plastic body which is custommolded to correspond to the individuals corrected dentures.

These prior art retainers have been subject to numerous objections both by the patient, as will as by the orthodontist. First, custom-molded retainers are relatively expensive due to the time and skills required in their manufacture. Secondly, such retainers are usually fabricated by a remotely located manufacturer from plaster casts supplied by the orthodontist, and this results in a serious delay in supplying the patient with the needed support. Further, these retainers usually cover and encase the entire dental arch and are, therefore, rather bulky and uncomfortable to the patient.

Heretofore, it was believed necessary to custom-mold these retainers ni order to faithfully reproduce therein actual impressions corresponding to the corrected teeth of each individual patient. This belief stemmed from the fact that tooth width, arch length and other dimensions of corrected dental arches vary with the individual person.

However, I have found through clinical tests and measurements of some 700 different patients that while there were dimensional differences in tooth width, arch length and intercuspid width (chordal distance) of the upper and lower six anterior teeth of different patients, there was very little, if any, difference in the curvature of the corrected dental arches in approximately 95% of the patients observed. In other words, in the greater majority of corrected dental arches, the straight line chordal distance between the cuspids of the maxillary arch and between the cuspids of the mandibular arch increases in direct proportion to the circumferential lengths of these arches.

SUMMARY AND OBJECTS OF INVENTION The present invention provides a tooth-positioning and retaining device in the form of a non-custom-molded, resiliently flexible, mouthpiece body which is dimensionally standardized so as to accommodate and afford the desired stabilizing support to the upper and lower six anterior teeth of the greater majority of corrected dental arches.

It is the primary object of this invention to provide a comparatively inexpensive standardized tooth-positioner and retainer which may be stocked by the average orthodontist and fitted to the average corrected patient with ease and facility, and without requiring preparation of the usual impressions, plaster casts, etc. heretofore necessary in the production of custom-molded positioners and retainers.

Another object is to provide a standardized tooth-positioner in the form of a resiliently flexible plastic mouthpiece which is formed with upper and lower generally arcuate troughs or grooves defined by limited area surfaces which will aflord the desired stabilizing support to the labial, lingual and incisal surfaces of the upper and lower six anterior teeth of a patient wearing the positioner, and which may be quickly and easily fitted to the individual patient simply by trimming off the distal edge portions of the mouthpiece to make its arcuate length conform to the arcuate length of the patients dental arch, measured from distal edge to distal edge of the cuspids.

For a further and more detailed understanding of the present invention and the various objects and advantages thereof, reference is made to the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a frontal perspective view of the tooth-positioning and retaining device of this invention showing the same in operative position covering the upper and lower six anterior teeth of the dental arches which are shown in broken lines;

FIG. 2 is a perspective view of the retaining device looking toward the rearward or lingual side thereof;

FIG. 3 is an enlarged, vertical sectional view taken through the central axis of the retaining device, as indicated by the line 3-3 of FIG. 2;

FIG. 4 is a horizontal sectional -view taken along the line 44 of FIG. 3 and showing the present retaining device in association with the upper or maxillary dental arch, the latter being shown in broken lines;

FIG. 5 is a similar view taken along the line 5-5 of FIG. 3 and showing the relationship of the retaining device to the lower or mandibular dental arch;

FIG. 6 is a horizontal sectional view taken along the line 6-6 of FIG. 3 and looking into the upper trough of the retaining device;

FIG. 7 is a horizontal sectional view taken along the line 77 of FIG. 3 looking into the lower trough of the retaining device;

FIG. 8 is a detailed vertical sectional view taken along the line 88 of FIG. 6;

FIG. 9 is a diagrammatic sectional view showing the relative location and dimensions of the lateral incisor-engaging ribs which are associated with the upper trough of the retainer; and

FIG. 10 is a similar view showing the relative location and dimensions of the incisor-engaging rib of the lower trough of the retainer.

3 DETAILED DESCRIPTION By reference to the drawings, it will be noted that the present tooth-positioning and retaining device takes the form of an integral, generally arcuate mouthpiece-like body generally indicated by the reference numeral 10. In accordance with this invention, the body is molded or otherwise formed with a standardized shape and With standardized dimensions so that it may be used by substantially any person who has undergone orthodontic correction and whose dental arches present six normal upper and lower front teeth. The body 10 is formed from a rubber-like, resiliently flexible, non-toxic material, such as natural rubber, or a silicone rubber elastomer which is non-irritating and compatible with the tissues of the mouth.

The body 10 includes a forward, labial flange portion 11, a rearward, lingual pad portion 12, and an intermediate incisal web, ledge or shelf 13 which interconnects the labial flange and lingual pad portions of the body. The labial flange portion 11 his a substantially smooth, generally convex front wall surface 14 and a substantially smooth, generally concave rear wall surface 15. The labial flange portion 11 is intended to fit between the anterior teeth and the lips of the wearer, and has a height to extend well over the gingival tissues of both the maxillary and mandibular arches when the anterior teeth are closed upon the incisal shelf 13 of the body.

The lingual pad portion 12 of the body is formed with a generally convex forward wall surface 16 disposed in rearwardly spaced, opposed relation to the concave wall surface of the labial flange portion. The Wall surfaces 15 and 16 define with the interconnecting incisal shelf portion 13 a pair of upwardly and downwardly opening grooves or troughs 17 and 18, respectively. The troughs 17 and 18 are generally arcuate and taper inwardly toward the incisal shelf portion 13 of the body. While the contour of the walls 15 and 16 follows the general contour of the upper and lower dental arches of the average human mouth in the region of the six anterior teeth, it will be noted that these wall surfaces are entirely devoid and free of individual tooth-like impressions such as to characterize the ordinary types of custom-molded retainers. In this regard, I have found that so long as a tooth is contacted with substantially equal force on its opposite labial and lingual surfaces and on its incisal surface, the tooth will be stabilized and prevented from movement, regardless of whether the force is distributed over the entire area thereof, or applied to a relative small and limited area of the tooth surface. By the same token, a slightly misaligned tooth may be urrged to a desired finally corrected position by the application of more force in one direction than another, even though the force be applied to a limited area of the tooth.

Accordingly, rather than forming the walls of the troughs 17 and 18 with individual tooth-like impressions to match the dentures of one particular person, I form the walls of the troughs 17 and 18 with relatively offset areas arranged in a predetermined pattern so as to provide stabilizing and/or corrective forces to the anterior teeth of practically any person having corrected dental arches and having six normal, upper and lower anterior teeth. Toward this end, the concave wall 15 of the upper or maxillary trough 17 is formed with a pair of relatively spaced, generally vertically arranged ridges, ribs or protuberances 19 which project into the trough 17 in position to contact the labial surfaces of the upper lateral incisors 20 of the wearer. As will be noted particularly in FIGS. 6 and 8, the ribs 19 are formed with horizontal continuations 19a which extend across and project upwardly from the bottom of the trough 17 for contact with the incisal surfaces of the upper lateral incisors 20. By the same token, the concave wall 15 of the lower or mandibular trough 18 is formed with a relatively wider, generally vertically arranged ridge-like protuberance 21 which extends into the trough to engage the labial surfaces of the four lower central and lateral incisors 22 and 23 of the wearer.

As previously indicated, tests and measurements made on approximately 700 different persons having corrected dental arches showed the following significant facts:

(1) The upper lateral incisors in each case were approximately 1 mm. shorter and 1 mm. thinner labio-lingually than the upper central incisors;

(2) The upper cuspids in each case were approximately 1 mm. longer and 1 mm. thicker labio-lingually than the upper central incisors;

(3) The lower six anterior teeth in each case were approximately the same length, but the lower cuspids were approximately 1 mm. thicker labio-lingually than the lower central and lateral incisors;

(4) The total arch length of the six upper anterior teeth in the smallest case was 38 mm. compared with a total arch length of 54 mm. for the corresponding teeth of the largest case;

(5) The straight line distance between the points of the upper cuspids in the smallest case was 30 mm. and in the largest case 40 mm.

(6) The widest upper central incisor encountered measured 10.5 mm. in width;

(7) In the narrowest case, the combined width of two upper central and lateral incisors was 13 mm;

(8) The combined width of the two lower central inisors was 12 mm. in the widest case; and

(9) The combined width of the four lower central and lateral incisors was 18 mm. in the narrowest case found.

Utilizing these statistics, I have found that the ribs 19 and their extensions 19a should project outwardly from the wall 15 and upwardly from the bottom of the trough 17, respectively, a distance of 1 mm. to conform to the normal, dimensional oifset of the upper lateral incisors relative to the central incisors. Also, the relatively thickened ridge or protuberance 21 of the lower trough 18 should project outwardly from the concave wall 15 a distance of 1 mm. to conform to the normal inset relationships of the four lower central and lateral incisors relative to the lower cuspids. I have also found that in order to prevent overlap or contact of the ribs 19-19a with the upper central incisors in the maximum tooth width cases, or contact with the upper cuspids in the minimum width cases, the inner edges of the ribs 19- 19a must be located 10.5 mm. outwardly on each side of the central axis A of the retainer body, or a total arcuate distance of 21 mm. apart from one another, and must not be over 2.5 mm. wide. By the same token, the ridge or protuberance 21 of the lower trough must not extend beyond 9 mm. on either side of the central axis A, or, stated another way, must not be over 18 mm. in arcuate length, otherwise, the ridge 21 would encroach upon the lower cuspids of the minimum width cases. These critical dimensions are shown in the diagrams of FIGS. 9 and 10, and should be closely adhered to in the manufacture of the present tooth-positioning and retaining device in order for it to be usable in the maximum number of cases.

Thus, to summarize, the upper or maxillary trough 17 of the body 10 is characterized by a central incisorreceiving region located between the ribs 19-19a and having an arcuate length of 21 mm., lateral incisor-receiving regions located adjacent the ribs 19-1951, each of which is 2.5 mm. in width, and cuspid-receiving regions located outwardly from the ribs 1919a. As will be noted from FIGS. 4 and 9, the cuspid-receiving regions of the trough 17 are approximately 1 mm. wider than the central incisor-receiving region and approximately 2 mm. wider than the lateral incisor-receiving regions. Also, the bottom surface of the upper trough 17 in its cuspidreceiving regions is approximately 1 mm. lower than in the central incisor-receiving region and 2 min. lower than the rib extensions 1%, as indicated in FIG. 8. The lower or mandibular trough 18 is characterized by a substantially uniform depth at the incisal shelf 13, but the trough 18 is approximately 1 mm. wider in its cuspid-receiving regions than in its central and lateral incisor-receiving region.

The present tooth positioning and retaining device is preferably manufactured and sold with a labial arch length of 54 mm. so as to span and encase the upper and lower six anterior teeth of the largest dental arch observed by me to date. Thus, when the orthodontist encounters a patient with an anterior arch (cuspid to cuspid) which is less than 54 mm. the distal end portions of the retainer body may be cut or trimmed off so that the ends of the labial flange will just cover the distal edges of the cuspids without encroaching upon the 'bicuspids.

It will thus be seen that the present invention provides a standardized, non-custom-molded, tooth-positioner or retainer which may be stocked in quantities by the orthodontist and quickly fitted to the great majority of his patients simply by cutting the distal edges of the labial flange and incisal shelf portions of the device so that its arch length will match the arch length of the six anterior teeth of the particular patient. If desired, the lingual pad portion of the device may be formed at its opposite sides with posterior extensions which project rearwardly along the lingual surfaces of the posterior teeth to provide additional stabilizing surfaces for the device.

Having thus described this invention, what is claimed 1. A standardized tooth-positioning and retaining device to be worn by orthodontically corrected persons having upper and lower six anterior teeth, ranging in widths from predetermined minimum to predetermined maximum widths, said device comprising a one-piece, resiliently flexible, mouthpiece body having a central axis and including a generally arcuate labial flange portion, a lingual pad portion extending rearwardly from said labial flange portion, and an incisal shelf portion connecting said labial flange portion with said lingual pad portion, the labial flange and lingual pad portions of said body being formed, respectively, with relatively opposing concave and convex wall surfaces converging toward the incisal shelf portion of said body and defining therewith upwardly and downwardly opening, generally arcuate troughs to receive the upper and lower six anterior teeth of an orthondontically corrected person,

the concave and convex wall surfaces of said troughs being devoid of individual tooth-like impressions, but the concave wall of the labial flange portion of said body being formed with protuberances projecting lingually into said troughs and arranged, upon closure of said anterior teeth on the incisal shelf portion of said body, to engage at least limited areas on the labial surfaces of the upper and lower lateral incisors without touching the adjacent cuspids, regardless of variations in tooth widths between said predetermined minimum and maximum widths.

2. A standardized tooth-positioning and retaining device according to claim 1, wherein the incisal shelf portion of said body is formed with a pair of ribs projecting upwardly into the upwardly opening trough of said body, said ribs being spaced from one another equidistantly on each side of the central axis of said 'body and being arranged upon closure of said teeth on said incisal shelf portion, to engage a limited area on the incisal surface of each of the upper lateral incisors only, regardless of variations in tooth widths between said predetermined minimum and maximum widths.

3. A standardized tooth-positioning and retaining device according to claim 1, wherein the protuberance formed on the concave wall of the labial flange and projecting within the downwardly opening trough of said body comprises a continuous ridge arranged to completely span the lower central incisors and at least a part of each of the lower lateral incisors upon closure of said teeth upon the incisal shelf portion of said body.

4. A standardized tooth-positioning an retaining device according to claim 2, wherein the protuberances formed on the concave wall of the labial flange and projecting within the upwardly opening trough of said body comprise a pair of relatively spaced apart, vertical ribs located contiguous to and in common vertical planes with the ribs formed on the incisal shelf portion of said body;

References Cited UNITED STATES PATENTS 2,775,036 12/1956 Kesling 3214 3,319,626 5/1967 Lindsay 3214 FOREIGN PATENTS 67,616 10/1957 France.

ROBERT PESHOCK, Primary Examiner

Images