fig1 and 2 show one particular embodiment of the present invention as it is prepared for use . as shown in these figures , a carrier 10 is provided with a tip 12 , a tapered portion 14 , and a portion 16 of fixed diameter terminating at a cut - off end 18 . the tapered portion 14 extends from the tip 12 to the point 15 . the carrier 10 is shown with a gutta percha plug 20 positioned thereon and extending at the rearward end to a plate 22 . the plug 20 terminates at a forward end 24 which is located approximately 1 . 5 mm back from the tip 12 . the length of the tapered portion 14 is shown at a . approximately one - third ( a / 3 ) of the tapered length 14 back from the tip 12 is a spherical projection or button 30 . this button 30 ( one of three ) is mounted on the outer surface of the carrier at a distance b from the tip 12 . on the fixed - diameter portion of the carrier 10 is a cylindrical tactile collar 32 which tapers outwardly from its point of juncture with the outer surface of the fixed - diameter portion 16 of the carrier 10 . the collar 32 serves to provide the user with a tactile indication of that point on the carrier , as well as serving as a stop for the oven arm in the heating of the gutta percha . as best seen in fig2 , the carrier 10 has three spherical bumps or buttons 30 projecting from the outer surface of the carrier 10 . in fig2 , the diameter of the carrier at the position of the bumps is indicated as cd 3 . extending axially along the tapered portion 14 of the carrier 10 is an elongated , shallow groove 40 . this groove makes it easier to withdraw the carrier from the gutta percha plug 20 . a plate 22 which is slidable along the carrier is placed at the proximal end of the plug 20 . when the carrier is to be removed from the root canal after placement of the plug 20 , the plate 22 serves to retain the plug 20 in position as the carrier 10 is withdrawn . as indicated in fig2 , the buttons 30 may be located equally spaced about the circumference of the carrier 10 at about 120 - degree locations . alternatively , the buttons 30 may be spaced approximately 90 degrees apart with the center button 30 being on the opposite side of the carrier 10 from the groove 40 . in the views of fig3 and 5 , a carrier 10 having spherical buttons 30 is shown . in this version , the buttons 30 are located at 120 degrees about the periphery of the tapered portion 14 . the carrier of the fig3 embodiment has a collar 32 with an adjacent stop plate 22 ′ which is slidable along the carrier 10 to retain the plug in place when the carrier is being withdrawn from the root canal . fig6 and 8 depict an alternative embodiment to that of fig3 and 5 . fig6 and 7 are side views of a carrier 110 having a tapered portion 114 , tip 112 , tactile element 132 and a retainer plate 122 . instead of the buttons 30 of the first embodiment , this carrier 110 has three elongate longitudinal ridges 130 projecting outwardly from the carrier surface . these longitudinal ridges 130 are rounded in shape and serve the same function as the bumps 30 , constituting stops for the carrier 110 when it is being inserted into a root canal with the gutta percha plug 20 mounted on the tapered portion of the carrier . being elongated , they provide better attachment of the gutta percha plug on the tapered portion of the carrier 110 than is afforded by the bumps 30 . otherwise , the use of the carrier 110 is essentially the same as that of the carrier 10 . the carrier 110 also has a shallow groove 140 along one side of the carrier to make it easier to withdraw the carrier from the gutta percha plug . fig9 and 11 depict still another embodiment of the invention in which a carrier 210 is shown having a tactile collar 232 , a tapered portion 214 , and a tip 212 . three spiral ridges 230 are positioned along the tapered portion 214 in the same manner as the ridges 130 of the embodiment of fig6 , except that these ridges 230 are spiraled slightly . otherwise , the carrier 21 is essentially identical to the carrier 110 of the fig6 embodiment . placing the ridges 230 in a spiral configuration gives added holding power for the gutta percha plug on the carrier . fig1 , 13 and 14 are simulated photographs of the three embodiments of fig3 and 9 , respectively . these views show that the carriers are devoid of a conventional handle which is typically significantly larger in diameter than the diameter of the carrier . since there is no handle to extend radially from the outer end of the carriers , more carriers can be inserted into a root canal without interference from others . with carriers having conventional handles , at most two carriers can be inserted at a time . with the feature of the present invention providing carriers without handles extending beyond the carrier , as many as four carriers can be inserted into a tooth , one for each root canal , and the outer ends can then all be severed at once . fig1 a - 15b , 16 a - 16 b and 17 a - 17 b are enlarged simulated photographs of the carriers shown in fig1 , 13 and 14 , respectively . fig1 , 16 and 17 depict essentially the same elements , designated by the same corresponding reference numerals , as those shown in fig1 , 13 and 14 , respectively . although there have been described hereinabove various specific arrangements of improved obturators in accordance with the invention for the purpose of illustrating the manner in which the invention may be used to advantage , it will be appreciated that the invention is not limited thereto . accordingly , any and all modifications , variations or equivalent arrangements which may occur to those skilled in the art should be considered to be within the scope of the invention as defined in the annexed claims .
dental obturators are used in the preparation of root canals in teeth . the subject obturators are so constructed that they bind at a particular distance into the canal , thereby precluding possible damage at the end of the canal . a variety of structural configurations is disclosed .