US 2789352 A
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April 23, 1957 A. o. WISEMAN TOOTH POLISHING CUP Filed June 27, 1955 IN VEN TOR. ADOLPH D. W/S'MA/V ATTORNEYS TOOTH POLISHING CUP Adolph D. Wiseman, San Francisco, Calif. Application June 27, 1955, Serial No. 518,189 6 Claims. (Cl. 32-59) V This invention relates to a tooth polishing cup of generally the type shown in my United States Letters Patent No. 2,017,881 of October 22, 1935.
One of the objects of the present invention is the provision of a tooth polishing cup having means for definitely limiting the width of the radially outwardly extending lip that is formed along the free edges of the cup when pressure is applied to the cup in a polishing operation, and at the same time such means provides a reservoir for a supply of tooth polishing material within the cup for delivery to such lip.
In explanation of the above, polishing cups are usually of relatively soft rubber or the like, and when the free edges along the open side of the cup are pressed against a tooth in a polishing operation, the marginal portion of the cup, around said free edges will stretch so as to form a radially outwardly projecting lip. Heretofore, the Width of this lip has been entirely dependent upon the pressure applied by the dentist, and since this lip will extend under the free, unattached margin of the gum tissue for cleaning each tooth along the gum line, injury to the connecting periodental fibers which attach the gum tissues to the neck of the tooth has resulted from the application of pressure greater than is sufiicient to clean the teeth to such fibers.
While the provision of reinforcing ribs within a cup, extending axially thereof, are of value in stifiening the portion of the cup that carries such ribs, they do not positively restrict the width of the lip that is adapted to project radially outwardly of the cup along the free edge of the latter, and furthermore, a pressure on the cup sulficient to spread the outer lip against the teeth to the ends of axially extending ribs within the cup results in a vibration against the teeth when the cup is rotated due to the ends of such ribs.
The polishing cup as disclosed in the said patent is illustrative of this type of structure.
Where a polishing cup encloses bristles, it is obvious that there is no storage space for an abrasive, and the bristles would prevent the desired spreading of the lip.
With the present invention, the outer marginal portion of the cup canot be expanded beyond a certain degree, and when so expanded the polishing area is substantially extended without decreasing the capacity of the reservoir that holds the abrasive to be fed to the polishing lip, and it is one of the objects of the present invention to provide a structure that enables the accomplishment of the above results.
Other objects and advantages will appear in the description and in the drawings.
In the drawings,
Fig. 1 is a greatly enlarged vertical sectional view taken through a cup lengthwise of the latter with said cup illustrated as being mounted on a shank piece that, in turn, is adapted to be held in a chuck or hand piece.
Fig. 2 is a top plan view of the cup of Fig. 1.
Fig. 3 is a greatly enlarged view, partly in section and 2,789,352 Patented Apr. 23, 1957 .that the cup is relatively small and the thickness of its side walls relatively thin as compared with the drawings.
In detail, the cup is generally designated 1, and is preferably-formed of soft rubber or the like and may be provided with a base 2 that is formed with a socket 3 for removably securing the cup onto a shank piece generally designated 4, which shank piece has a bulbous end 5 adapted to be held in socket 3. The shank piece includes a shank 6 for securement in a dental handpiece.
The present invention is not particularly concerned with the manner in which the cup is held onto a handle or to a shank piece or dental handpiece, hence the above description is merely intended to be illustrative of one way in which the cup may be supported.
. The base 2 provides a bottom wall 7 for the cup, and
the; lateral sides 8 of the cup preferably extend slightly divergently outwardly from said base, terminating in an outer marginal portion or lip 9 that is coextensive with said side walls. The marginal portion or lip 9 has the circular outer free edge 10 of the cup 1.
Since the taper of walls 8 is quite slight, as indicated in the drawings, said walls may be said to be generally cylindrical, although said walls actually form the frustum of a cone sovthat the cup portion is frusto-conical in shape with the closed bottom at the smaller end and the open end at the larger diameter end, and the said walls become progressively thinner in direction outwardly of the base 2.
At the juncture between the lip portion 9 and the remainder of the cup, and which juncture is adjacent to but is spaced from the free end edge 10, is an internal radially inwardly projecting rib 12, the upper and lower sides (radially facing sides) of which extend convergently in direction radially inwardly to intersect along a line defining the inner diameter of said rib.
While the walls of the lip 9 may be substantially of uniform thickness axially of the cup, this thickness is less than the minimum thickness of walls 8 which is immediately below rib 12, and the upper slanted surface 13 of the rib is substantially wider in direction transversely of the rib than the lower side 14 of the rib. This is important for the reason that when the lip 9 is flattened against a tooth, such as indicated at 15 in Fig. 3, not only i the inner surface of the lip 9 against the tooth, but also an additional width equal to the thickness of the wall 8 at the rib, and part, if not all, of the upper surface 13 of the rib. Thus, while the rib 12 will restrict the distance that the lip 9 will extend radially outwardly of the cup, it will also provide an additional polishing surface that is continuous around the cup.
The gum tissue 17 is free from the tooth along the gum line, and as the lip 9 cannot expand beyond the limit permitted by the rib 12, it will be seen that with the present design, the lip is of a width that cannot extend so far. below the gum as to injure the periodental fibers which attach the gum tissue to the neck of the tooth, as would be likely to occur, and frequently does occur where an accidental additional pressure on the cup would expand the lip so that its outer edge would objectionably engage said fibers in a tooth polishing operation.
The inner sides of the lip 9 may be formed with uniform ridges 21. In themselves, such ridges are not new and heretofore have been provided for the purpose of providing greater efliciency in a polishing operation, since araaaaa the abrasive powder or material passes betweensuchridged portion and the surfaces of the teeth. In the present instance, the lower ends of said ribs, as seen in Fig. 1 integrally connect with the rib 12,- lience tend to pull the surface 13 of the rib against the surface of the teeth when tension is placed on these ribs by flexing the lip 9 outwardly. Also said ribs will reinforce the' lip along the line of juncture between the lip 9 and the rib The portion of the cup 1 below rib 12 provides a reservoir 18 for the tooth polishing material 19 (Fig. 3) which may be powd'er, paste or a slurry, and the provision of lip 12 prevents this polishing material from being discharged too rapidly onto the surfaces of the teeth. Inasmuch as the inner surface '20 of the walls 7 taper outwardly in direction toward the rib 12, are material in the reservoir 18 will move to the rib, where its movemen: wil be checked by the rib, but 'said material will be pushed radially inwardly ever the lower surface 14 or the rib, and then gradually onto the outer surface 13 or the rib and finally onto the ridged inner surface of the lip 9. In this operation, it is understood that the cup is being rotated about its axis, hence centrifugal force will be'acting on the abrasive material.
It i to be understood that the specific description is not intended to be restrictive of the invention, but merely illustrative or a preferred form. Also the term rubber is not to be considered necessarily restrictive to conventi'onal rubber but is intended to cover any material having the necessary characteristics which are found to exist in rubber.
l. A dental tool comprising: a soft rubber tooth polishing cup for holding abrasive material-and having 'a bottom wall and generally cylindrical side walls and an annular free outer edge, an annular, radially inwardly directed rib coaxial with said side walls projecting into said clip, said "rib being space-d between said free edge and said bottom wall and closer to the former, the portion of said's'ide Wall's between said rib and said free "edgedefining a'readily distortable flexible annular-lip adapted to stretch to a radially outwardly extending positionupon application of pressure on said clip axially thereof in the directio'n of said free edge when the latter 'is against a tooth.
2. A dental tool comprising a "soft rubbertoothpolishing cup for holding abrasive material having a "bottom wall 'and-"ge' n'erally' cylindrical side walls extending away from"said bottom wall and tcrmina ting in a n annular lip remote "from said bottom wall, an annular rib integral with s'a'id'-'cup, the walls ofsaid lip being inclined outwfa'r'clly' axi'ally of said cup 'audbeing relatively thin and readily "stretchable "to a position e) ;tcn ding'radia1 ly autwar dlyof the axis'of said'cup uponapplication espressure'on -said cup axially thereof in a direction toward said lip when "the latter is against a tooth 'wher'eby"'the radially inwardly facing surface of "said lip 'WiIPengag'e said tooth'for 'polishingthelatter, and an annular radially inwardlyprojecting rib integral with said-cup at thejunc ture betweensaid lip and the remainder of said cup having an axially outwardly facing surface that is coextensive with said inner 'surfaceof 'said lip when "said-lipis in polishing position extending radially outwardly of said axis.
3 A dental tool comprising: a soft rubber tooth polishing 'cupfor'holding abrasive material and h'aving'a bottom wall and generally cylindrical side walls and anannular free outer edge, anfannulanradially inwardly'directed rib coaxialjwith'said side walls projecting into sa'id'cup, said rib"being' spaced between said free edge'and said bottom wall and closer to the former, the. portion 6r said side walls betweensaid rib and said free edge defining ,a
readily distortable flexible annular lip adapted tostretch to a radially outwardly extending position upon application of pressure on said cup axially thereof in the direc tion of said free edge when the latter is against a tooth, said walls being slightly inclined outwardly relative to the axis of said cup in a direct-ion away from said bottom wall.
4. A dental tool comprising a soft rubber cup having a bottom wall, side walls and an open end opposite to said bottom Wall, an annular radially inwardly projecting rib around said side walls integral therewith and coaxial with said cup and spaced from said bottom wall for de fining a barrier to the free flow of abrasive material in said cup to said open end upon revolving said cup about its axis, said lip being relatively thin and adapted to stretch to a position projecting radially outwardly relative to said axis when said lip is in engagement with the surfaee of a tooth and pressure is applied to said cup axially thereof toward said tooth, the axially fa'cin g side of said rib generally facing said bottom wall-beingslanted in cross sectional contour in a direction from said side wall toward said lip rib and said side Wall being slanted outwardly in direction away from said bottom wall whereby said abrasive material betweensaid rib and-*said -bottom Wall will be gradually 'moved acrosssa'id lip and to said lip upon said revolution-of said cup.
5. A dental tool comprising a'so'ft rnber frusto-conical polishing cup terminating at its larger diameter end in a free circular edge defining the-outline of'the -open end of said cup and a base at the end of said cup'opposite to said ope'nend providing a bottom wall for saidcup, an annular radially inwardly directed rib coaxialwithsaid cup and integral therewith projecting into-the same at-"a point adjacent to but spaced from "saidfreeedge, ridges integrally connected at one of their'ends withsaid rib and integral with the marginal portion of said :cup along said free edge and extending outwardly from said rib "relative to said bottom Wall, said margi'nal-portionarid ridges being adapted to stretch to radially outwardly extending position "relative-to said rib upon application of pressure against said cup axially-thereof in direction toward said free edges when the latter are in engagement with a tooth.
6. -A dental tool comprising an elongatedso'ftrubber "polishing'cuphaving a bottom at one end and *afree circular-edge at -the-opposite end defining the openend ofisaidcup, frusto-conical sidewalls extending between said free "edge and 5 said bottom I wall carrying said" free 'edge'with said free edge being at thelargeshdiameter end 'of said side walls an' annular rib integral "with-"said *side walls adjacent to but spaced from-said free=edge "'tlierewith'and integrally connected at one of their ends iwithzthe surface of said rib that faces generally toward-said free. edge, said ridges extending substantially between said rib and free edge' axially of said cup wherebytension in' anaxially outer'dircctionwill be placed on said surface of said rib when said lip and the ridges thereon arefiexed to=extend radially outwardly of the axis of said cup.
References Cited in the file of this patent UNITED-STATES PATENTS f'.1.1;'62'6, 1f21 W yn --;.-Apr. -,2 ,-:l227 "2,017,881 'Wiseman -lIOct, 22,1935