referring to fig1 , and 3 the structure of an attachment according to the present invention is shown . the support 1 of the attachment a is attached to the partial denture . it has relatively wide slot 2 and a narrower slot or slide recess 2 &# 39 ; which has a cross - section form so that it is substantially horizontal and therefore at a right angle to the major axis of the teeth . as shown in detail in fig2 or 3 a lock member 3 has a surface in the form of a tooth and is provided with an extending or sliding member 3 &# 39 ;. the member 3 rides in the recess 2 and the extending sliding member rides in recess 2 &# 39 ; to prevent the lock member 3 from being displaced upwardly from the support 1 . the lock member 3 may be moved lingually or bucally by simply pushing it with a fingertip . the support 1 includes a recess 4 and a pin hole 5 which receive the pin 5 &# 39 ; mounted on the lock member . the abutment tooth d is provided with a crown 6 having a protruder 7 which also has a pin hole to receive the pin 5 &# 39 ;. therefore the connection of attachment a of the partial denture to the abutment tooth d can be accomplished by positioning the support so that the protruder on crown 6 of the abutment tooth d is inserted into the recess 4 of support 1 . then sliding lock member 3 is moved so that the lock pin 5 &# 39 ; slides through the pin hole 5 and into the hole of the protruder 7 . as can best be seen in fig4 c the extending slide member 3 &# 39 ; has a guide slot 3 &# 34 ; formed in one of its side portions . this slot 3 &# 34 ; is provided to allow the lock member 3 to slide over a limited range within the support . during assembly the lock member 3 is inserted into the support and the pin 8 is inserted through the hole 8 &# 39 ; and the slot 3 &# 34 ; and permanently affixed there . hence during normal operation the lock member may be slid back and forth between a locked and unlocked position but may not be totally disengaged from the support . therefore the lock member cannot be accidentally dislodged or lost . the lock member 3 is retained in its positions corresponding to a locked or unlocked condition by the use of a spring loaded lock pin and two detents . the placement of the pin and detent can best be seen in fig4 a and fig5 while an alternate construction is shown in fig6 . the first construction , as seen in fig4 a and 5 , uses a pin mounted in a hole in the lock member 3 and biased by spring 9 &# 39 ;. the pin is urged against the wall of the support and will engage the detents 9 &# 34 ;. the placement of the detents correspond to the locked and unlocked positions of the pin 5 &# 39 ;. when the lock member 3 is fully inserted into the support the pin 5 &# 39 ; will engage the hole in the protruder 7 to secure the partial denture to the abutment tooth . the pin 9 will be retained in the left most detent indicated as 9 &# 34 ; of fig4 a . when the lock member 3 is slid to its unlocked position and pin 5 &# 39 ; disengages the protruder the pin 9 will engage the right most detent indicated as 9 &# 34 ; in fig4 a . thus the lock member is retained in either the locked or unlocked position but may be slid by finger pressure . fig6 shows an alternate arrangement of the locking pin and detents which is to be used when the lock member 3 is too small to acommodate the spring 9 &# 39 ; and pin 9 . in this case a hole is formed in the tooth of the partial denture t and may be provided with a sleeve 9a . the spring 9 &# 39 ; urges the pin 9 against the lock member 3 and hence engages the detents 9 &# 34 ; in the lock member 3 . the result is the same as that obtained in the construction first presented i . e . the lock member is retained in either a locked or unlocked position unless finger pressure is applied to it . this feature is important since it retains the lock member in a locked position when the denture is fixed in the mouth . speech or the mastication of food will not accidentally misplace the lock member . likewise when the denture is being inserted into the mouth the lock member must be in an unlocked position to allow the proper placement of the protruder within the recess 4 . this feature prevents the lock member from accidentally moving to a locked position before it is properly placed . the connector 10 protrudes from the side of the attachment opposite the recess 4 and is attached to the frame 11 by means of a connector 10 &# 39 ;. a variety of different types of partial dentures can be mounted on the frame in accordance to the condition of the patient . fig5 shows a first embodiment of the standard type of attachment according to the present invention . this attachment is used in cases where the first premolar or second premolar or the like are defective but where there is a molar behind them . it can also be adapted in cases where all the teeth from the first premolar or second premolar to the molar are defective . the teeth are relatively wide and high and this attachment can be used in many cases where the upper and lower teeth are defective . referring to fig5 this embodiment will be described in greater detail . the side portion of support 1 of the attachment a is provided with the recess 4 dimensioned to receive the protruder 7 which projects from the crown 6 of the abutting tooth d it is also formed with a relatively wide slot 2 and a sliding recess 2 &# 39 ;. these are dimensioned to receive the lock member 3 which is in the form of a false tooth and has a sliding member 3 &# 39 ; integrally formed with it and which is received by the lower and narrower section of the slot . pin 9 and spring 9 &# 39 ; are fitted by a hole in the lock member 3 . the end of the pin is received by a detent 9 &# 34 ; in the wall of the support . once the lock member and support have been assembled pin 8 is inserted through a hole in the bottom of the support 1 and passes through a slot in the sliding member 3 &# 39 ; so that the lock member cannot be displaced from the support . the frame 11 of the denture t is connected to the protruder 10 at the lower side portion of the support 1 . when the partial denture is to be secured within the mouth this assembly is fitted over the protruder 7 and the locking member is operated to move the lock pin 5 &# 39 ; through the opening in the protruder to thereby secure the partial denture in place . fig6 shows an alternate embodiment of the present invention where the tooth formed is not quite as tall as the one illustrated in fig5 . there is not enough room to mount the pin 9 and spring 9 &# 39 ; within the lock member 3 . here the pin 9 and spring 9 &# 39 ; is mounted within a sleeve 9a mounted on the frame 11 of the partial denture . the lock member 3 is provided with detents 9 to retain the lock member 3 in either its locked or unlocked position . fig7 shows a third embodiment of the invention . here the attachment takes the form of two teeth and thus is much wider than the other embodiments . the slot in the support is provided with a second slot 2a in its lower portion which is dimensioned to receive a second sliding protruder 3a which is formed as a integral member of lock member 3 . since the lock member is relatively large the pin 9 and spring 9 &# 39 ; are mounted therein . here again the frame 11 of the partial denture t is secured to the attachment by means of connector 10 and connecting pin 10 &# 39 ;. it must be appreciated that the support and lock member may be fabricated to take the form of any number of teeth . also the lock member and support may be provided with many different configurations of slots and protruding members to allow the lock member to slide relative to the support . fig8 shows an embodiment of the invention which is similar to the multi - toothed arrangement of the embodiment shown in fig7 . however here the height of the lock member 3 is reduced and therefore the pin 9 and spring 9 &# 39 ; cannot fit in the lock member 3 . here they are fitted into sleeve 9a which is mounted partially within the attachment itself and partially within the denture t . the detents 9 &# 34 ; are formed within the lock member 3 at a position close to the secondary slot . fig9 shows a fifth embodiment of the invention , unilateral distal extension partial denture , which is useful when unilateral teeth are missing , e . g ., when the first molar and second molars are defective . in this application the attachment a is constructed similar to the previous examples and is connected to the partial denture t which has a prosthetic gingiva 8 &# 34 ;. the lingual bar 11a is formed as an extension of the frame 11 . the abutment tooth d and the next tooth d &# 39 ; are crowned to receive the end of the lingual bar 11a . when in place this attachment a is secured by means of the removable attachment . the prosthetic gingiva 8 &# 34 ; is disposed against the toothless gum and the end of the lingual bar 11a is disposed against the crowns 6 of the abutment teeth d and d &# 39 ;. this is a significant improvement over the dentures known in the prior art which uses two bars which encircle the tooth on both the left and right sides . hence this improved denture may be provided at a lower cost but is more comfortable than previous ones . another factor which reduces the cost of this denture is the fact that the abutment teeth may be crowned using any one of the special metals normally used , for example , gold alloy , regular alloy , or special alloy , etc ., costly procelain capping is not necessary . fig1 and 11 show a denture which may be used where there are extensive bilateral tooth defects and only the canine teeth remain . reinforcement bar b is connected to crowns mounted on the canine teeth d &# 34 ; which are each provided with protruders 7 . thereafter the denture is formed having the attachments a , teeth t and artificial gingiva 8 &# 34 ;. the lingual bar 11b connects the molar and incisor carrying portions of the frame . the denture is attached on either side by means of the attachment a engaging the protrusion 7 of the canine teeth . here the abutment teeth are utilized without the need for cutting as would be the case if a ceka - anchor arrangement was to be used . an alternative to the form of the embodiment shown in fig1 and 11 is a bilateral distal extension partial denture used when molars and premolars are missing on both sides but the canines and incisors are healthy . in such a case a partial denture similar to the one shown in fig1 and 11 is used but the prosthetic incisors and associated prosthetic gingiva are omitted . they are replaced by a lingual bar which is dimensioned so that it will be positioned behind the natural incisors when the denture is in place . this lingual bar is joined to the molar carrying frame or to the attachment . al alternative to the use of a lingual bar in cases of unilateral defects is to support the partial denture by a telescopic crown . this is particularly useful when teeth between the canine and rearmost molar are missing . the telescopic crown is dimensioned to be received by the rearmost molar and the canine is provided with a crown having a protruder . the partial denture is constructed with the telescopic crown at one end and a connector , according to the present invention , at the other end . thus when the partial denture is inserted one end is connected to the crowned canine by means of the connector and the other end is connected to the rear molar by means of the telescopic crown . thus it is apparent that the attachment described has several outstanding features . the sliding lock member and support with their associated pins and springs may be mass produced however they are easily adaptable for use with dentures custom fitted to each individual patient . the protruder can be attached to any tooth or tooth fragment which will retain a crown . no work on the abutment tooth is necessary except for the attachment of the crown . the attachment by means of the hole in the protruder and the locking pin on the attachment is elegantly simple yet secure . since the attachment is fabricated in the shape of a tooth its use is far more cosmetically acceptable than devices known in the prior art . while i have described my invention to some detail and in several embodiments , it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention . therefore the invention should not be limited by the description above but only by the claims which follow .