AU650567B2 - Dental syringe tip and adaptor - Google Patents

Description

Our Ref: 435265 P/00/011 Regulation 3:2 650587

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT r o

D

Applicant(s): Address for Service: Warren L. Davis 3026 Sullivan Avenue Rosemead CALIFORNIA 91770 UNITED STATES OF AMERICA David R. Wasserman 2095 Mohigan Way LAS VEGAS Nevada 89109 UNITED STATES OF AMERICA DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Strojt SYDNEY NSW 2000 Dental syringe tip and adaptor Invention Title: The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 DENTAL SYRINGE TIP AND ADAPTOR 1 BACKGROUND OF THE INVENTION 2 This invention relates to dental syringe tip assemblies, 3 and more particularly to dental syringe tip assemblies having 4 a disposable tip and an innovative adaptor.

For the past twenty-five years, dentists have been using 6 a three-way syringe. An air tube and a water tube join toget- 7 her at the handpiece. Two operating buttons are provided on 8 the handpiece body to allow activation by the dentist of the 9 air or water. By depressing the air button, air flows out of the tip into the appropriate area of the patient's mouth to 11 dry the field of operation. By depressing the water button, 12 a passive flow of water is emitted to clean and float away 13 debris and congestion from the field of operation. By depress- 14 ing both buttons simultaneously, a spray of air and water is 15 emitted which flushes away debris which can then be vacuumed 16 from the oral cavity. Typical of a three-way syringe assembly 17 is that shown in U. S. Patent No. 3,874,083 to Buckley.

18 During these twenty-five years, there has only been one 19 sigr ificant improvement made to this essential piece of dental equipment. In approximately 1979, the tip of the syringe was 21 made removable to allow for sterilization. Before 1979, tips 22 were disinfected and cleaned by simply wiping them with al- 23 cohol. With the development of the removable tip, steriliza- 24 tion of each tip could be accomplished through the use of steam or chemical heat procedures. However, if done uwit the ap- 26 propriate frequency, thu tip becomes clogged and unusable in 1 several months. This is due to minerals and other impurities 2 in the steam used in an autoclave which cause? alkaline and 3 calcium deposits to build up in the orifices of the tip which 4 interrupt the flow of air and water from the tip. The air and water orifices in the tip are quite small, so that any ir- 6 regularities occurring during fabrication will also decrease 7 the life expectancy of the tip. Any plugging of the tip 8 orifices results in both a loss of spray pressure as well as 9 a loss of spray accuracy. Tips are conventionally made out of metal and it would be cost prohibitive to discard a metal 11 tip after only a single use.

12 With the rising incidence of communicable diseases such 13 as hepatitis and acquired immune deficiency syndrome, extreme S 14 care must be taken to prevent the transmission of germs (viral 15 or bacteria) from one patient to the next. With the conven- S 16 tional metal tips, it is necessary to sterilize the tip after 17 each patient use. This is due to a condition that occurs in S: 18 the end of the tip during use known as water retraction (also S 19 called suck-back or draw-back), which is a negative pressure applied to the water line. In a syringe, water retraction is S 21 used to prevent siphoning or dripping from the water line.

22 When water retraction occurs, water, saliva and blood from the 23 patient's mouth can be drawn back into the end of the tip and 24 then passed on to the next patient. This provides the opportunity for the transfer of infection from one patient to the 26 next. Also, latent bacterial growth can be promoted in both 1 the tip and the entire water system lines because of the 2 existence of this potentially contaminating material. Both 3 the Center for Disease Control and the American Dental Associa- 4 tion recommend that water lines be non-retracting. To further mitigate this possibility of cross-contamination from one 6 patient to the next, the routine sterilization of handpieces 7 as well as air/water syringes is desirable. In the case of 8 handpieces and air/water syringes that cannot be sterilized, 9 it is recommended that other complete cleaning and disinfection procedures be followed.

11 A disposable syringe tip is disclosed in U. S. Patent No.

12 4,026,025 to Roderick S. Hunt. The plastic tip is disclosed S 13 as flexible and can be easily bent by hand without any special 14 tools or heating. Such a flexible tip would suffer from the 15 limitation that it would not function as a retractor. It is 16 necessary when applying air, water or a spray to the patient's 17 mouth to be able to use the syringe tip as a retraztor to move 18 the patient's tongue, cheeks or lips. If the syringe tip were 19 flexible, it would fail to perform this important retraction function.

S 21 The syringe tip and mounting collet disclosed in the Hunt 22 patent also have further design limitations. The chamfered 0: 23 surface on the end of the syringe tip effectively directs the 24 air away from the water thereby impeding the formation of the water spray which is so important in a three-way syringe. The 26 small circular air passages further limit the amount of air 0693k/lfg 4 exiting the end of the tip and these air passages would be subject to being crimped closed when the flexible tip is bent. The syringe tip is press fit on the end of a small nipple on the collet in such a manner that the air and water pressure leaving the handpiece body and entering the syringe tip would lead to a loosening of the press fit thereby causino the syringe tip to dislodge from the nipple. This design is also not adaptable to most three-way piece syringe assemblies on the market.

SUMMARY OF THE INVENTION To ameliorate at least one of the disadvantages of the prior art, the invention in one broad form provides a syringe tip adaptor for connecting a syringe tip to a handpiece body, the syringe tip adaptor comprising: a) a generally cylindrical body having a hollow interior, on o earior suorfcce- of e cyl;Ondcf Yoy b) first means for securing the cylindrical body to the handpiece body, c) channel means for providing an air passage from the handpiece body through the cylindrical body and into an air passageway in the syringe tip, the channel means being S:"disposed relative to the hollow interior of the cylindrical body, d) a baffle mounted within the hollow interior of the cylindrical body, the baffle including an axial opening, and e) an elongated tapered male connector formed integrally with the baffle and having an axial opening therethrough adapted to cooperate with a central passageway in a syringe tip to provide a water passa(.;w, from the handpiece through the adaptor and into the syringe tip S: whereby when a syringe tip is mounted on the tapered male Sconnector the syringe tip will be tightly held on the tapered male connector to prevent axial rotation of the syringe tip and to ensure that the air and water passageways do not leak into each other.

Preferably the adaptor also comprises a rounded Sshoulder surrounding the male connector at the location 0693k/lfg 4a where the male connector joins the baffle to provide a sealing surface when a syringe tip is mounted on the male connector.

The invention also provides a dental syringe assembly .s2'rae-f s<er-rb\ky cr\ 0 comprising a handpiece body including means for mounting -athe syringe tip assembly to the handpiece body, said syringe tip assembly comprising: a) a syringe tip adaptor for connecting a syringe tip to a handpiece body comprising: 1) a generally cylindrical body having a hollow interior, 2) first screw threads on the exterior surface of the cylindrical body for connecting the cylindrical body to the handpiece body, 3) channel means for providing an air passage from the handpiece body through the cylindrical body and into an air passageway in the syringe tip, the channel means being disposed relative to the hollow interior of the cylindrical body, 4) a baffle mounted within the hollow interior of the cylindrical body, the baffle including an S" axial opening, and 5) an elongated tapered male connector formed integrally with the baffle and having an axial S* opening therethrough adapted to cooperate with a central passageway in a syringe tip to provide a water passageway from the handpiece through the adaptor and into the syringe tip whereby when a syringe tip is mounted on the tapered male connector, the syringe tip will be tightly held on the tapered male connector to prevent axial rotation of the syringe tip and to ensure that the air and water passageways do not leak into each other, and b) a syringe tip mounted on the syringe tip adaptor.

BRIEF DESCRIPTION OF THE DRAWINGS t f a (<7 1 Figure 1 shows an exploded view of a dental syringe as- 2 sembly incorporating the present invention.

3 Figure 2 shows a disposable syrii.-- tip of the present 4 invention.

Figure 3 shows a cross-section taken along line 3-3 of 6 Figure 2 of the disposable syringe tip of the present inven- 7 tion.

8 Figure 4 shows an enc. _Jew taken along line 4-4 of Fig- 9 ure 2 of the exit end of the disposable syringe tip of the present invention.

11 Figure 5 shows a cross-section of the exit end of the 12 disposable syringe tip taken along line 5-5 of Figure 4.

13 Figure 6 shows an end view of the entrance end of the 14 disposable syringe tip taken along line 6-6 of Figure 2.

Figure 7 shows in section the adaptor of the present in- 16 vention.

17 Figure 8 shows the adaptor with a portion of the syringe 18 tip mo,,nted thereon.

19 Figure 9 shows in partial cross-section an alternate embodiment of the syringe tip and adaptor of the present inven- 21 tion.

22 Figure 10 shows in cross-section a coupling device used 23 in an alternate embodiment of the present invention.

24 Figure 11 shows in partial cross-section the syringe tip coupling device- adaptor assembly of an alternate embodiment 26 of the present invention.

1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 2 A dental syringe assembly 10 includes a conventional hand- 3 piece body 12 on which is mounted a syringe tip 14. The tip 4 14 is an elongated cylindrical member preferably made of a rigid plastic material. The tip 14 is provided with a bend 6 17, at preferably an angle of approximately 30", to provide 7 easy access to any portion of the patient's mouth during use 8 of the syringe assembly. An adaptor 20 screws into a threaded 9 opening 13 in the handpiece body 12 and is sealed toward one end of the adaptor by a first rubber O-ring 16. A second 11 rubber O-ring 22 provides a seal at the midpoint of the adaptor 12 13 The tip 14 is press fit onto a tapered male connector 21 1" 14 (see Figures 7 and 8) that is mounted axially in the interior 15 of the adaptor 20. A collet 26 and a third O-ring 24 provide 16 a seal for the tip 14 male connector 21 assembly. A nut 28 17 comprises a locking assembly and screws onto the threads 44 18 on the outer surface of adaptor 20 to secure the tip 14, collet 19 26 and third Oring 24 in place. Each of these parts, other than the specific tip 14 and the specific adaptor 20, are the 21 conventional assembly for a three-way syringe tip assembly such 22 as Model No. 23-0090-00 or Model No. 90-0125-00 sold by the 23 Adec Corporation of Newberg, Oregon or the DCI 3-way syringe 24 sold by Air-Con Inc. of Portland, Oregon.

The tip 14 is shown in detail in Figures 2 through 6.

26 The tip 14 is designed to be disposable after a single use.

1 2 3 4 6 7 8 9 11

S

*5 The tip material is fabricated in a single-step extrusion process, and is made from any rigid transparent plastic. A rigid plasticsis preferred to fulfill the need to use the tip for continued retraction of the check and tongue by the dental operator. In a preferred embodiment, the tip 14 is made from a polycarbonate plastic or other rigid plasticg materials.

Suitable rigid plastic transparent material is that sold by General Electric Co. under the trademark Ultem 1000 or that sold by Victrex Corp. under the trademark Peek.

As shown in Figures 2 through 6, a central water passageway 32 runs the entire length of the tip 14 and is used to deliver water from the handpiece body 12 to the patient's mouth.

Three air passageways 34 also run the entire length of the tip 14, are disposed circumferentially about the central passageway 32 and are used to deliver air from the handpiece body 12 to the patient's mouth. If both air and water are delivered through the tip 14 simultaneously, a spray results at the exit end 15 o" the tip 14.

In a preferred embodiment, the elongated cylindrical member comprising tip 14 has a diameter in a range generally of .140" .150", and most preferably has a diameter of approximately .145". The water passageway 32 has a diameter in a range of generally .035" .039", and most preferably has a diameter of approximately .036". Each air passageway 34 comprises in cross-section an arcuate section (see Figure 3) approximately one-third of the circumference of the tip 14.

1 Each arcuate section has a width in a range of generally .016" 2 .020', an. preferably has a width of approximately .017".

3 The arcuate sections are separated from one another by thin 4 support segments 38, each having a thickness of approximately .018".

6 While the air passages 34 shown in Figure 3 are shown in 7 cross-section as an arcuate section, other cross-sectional 8 shapes can also be used such as rectangular sections, trian- 9 gular sections and elliptical sections. Likewise, the central water passageway 32, shown in Figure 3 as having a circular 11 cross-section, can alternatively have other cross-sections 12 such as square, rectangular, elliptical or triangular.

13 The support segments 38 are also shown in Figure 3 as "14 being symmetrically oriented about the circumference of the 15 tip 14 approximately 120° 4" apart. It is also possible to 16 asymmetrically orient the support segments 38 about the circum- 17 ference of the tip which would result in some of the air 18 passages 34 being longer in cross-section than others. Also, 19 while three support segments 38 are shown, as few as two or 20 as many as four or more support segments can also be used.

21 As shown in Figures 4 and 5, at the exit end 15 of the 22 tip 14, the air passages 34 combine to form a continuous 360 23 annulus 35 around the water passage 32. This can be achieved 24 -luring the fabrication of the tip 14 by die-cutting to the desired depth each support segment 38 inward from the exit end 26 15 of the tip 14. While die-cutting is the preferred way of 1 forming the continuous annulus 35, other methods can be used 2 to remove the support segments 38 to the desired depth. In 3 the preferred embodiment, the depth of the continuous annulus 4 35 from the exit end 15 of the tip 14 inward is approximately .125".

6 The continuous annulus 35 achieves a quite effective 7 mixing of the air and water which results in a uniform spray 8 which is easily directed by the dental operator at the needed 9 locations in the patient's mouth.

Figures 7 and 8 show the adaptor 20 that is used to 11 connect the tip 14 to the handpiece body 12. The adaptor 12 preferably made of metal, comprises a generally cylindrical 13 body having a hollow interior. The exterior wall 40 of the 14 adaptor 20 has a first set of threads 42 for attaching the S 15 adaptor 20 to the threaded opening 13 in the handpiece body 16 12. A baffle 46 extends across the hollow interior of the 17 cylindrical adaptor 20. Formed integrally with the baffle 46 S. 18 is a male connector 21 formed as a cylindrical member and 19 having an axial opening 48 therethrough. The male connector 21 is tapered to receive the entrance end 53 of the tip 14.

S 21 The male connector 21 is also formed of metal and has an outer 22 diameter at its forward end 54 of approximately .032" and 23 tapers out at its bottom end 55 to a diameter of approximately 24 .038". The male connector 21 is press fit into the water passagewaf 32 of the end 53 of the tip 14. A rounded shoulder 26 56, which surrounds the bottom of the male connector 21 at the 1 location where the male connector 21 joins the baffle 46, 2 cooperates with a resilient O-ring coating 60 on the entrance 3 end 53 of the tip 14 (see Figure 6) to form a seal to prevent 4 water from leaking. The baffle 46 communicates at 59 through axial opening 48 with a water line by way of a valve (not 6 shown) in the handpiece body 12.

7 A plurality of circumferentially arranged channels 62 in 8 the cylindrical body provide openings to allow the air from 9 the handpiece body 12 to pass to the hollow interior of the adaptor 20 and then into the air passageways 34.

11 A second set of threads 44 is provided on the exterior 12 wall 40 of the adaptor 20. These threads 44 cooperate with 13 the threads in nut 28 to seal the tip 14 to the adaptor 14 The forward interior portion of the adaptor 20 is provided 15 with an hexagonal cross-section 58 which allows the use of an 16 allen wrench to screw the adaptor 20 into the opening 13 in 17 the handpiece body 12.

18 The present invention yields significant advantages over 19 the syringe tip-adaptor assemblies used previously. By using 20 a disposable syringe tip, a source of infection and cross- 21 contamination of micro-organisms from one patient to the next 22 is eliminat d. When a three-uay syringe is used, back pressure 23 is created at the end 15 of the syringe tip 14 whenever 'he 24 air and water flow is abruptly cut off. This back pressL.re can cause contaminated water, saliva or blood to be drawn back 26 into the tip openings. 1f the tip 14 were to be used on a 1 second patient, any micro-organisms in the contaminated water, 2 saliva or blood from the first patient could infect the second 3 patient. A disposable tip 14 used for each patient eliminates 4 this problem.

Existing metal tips should be sterilized prior to use b using an autoclave sterilization system. The disposable tip 7 eliminates the need for this autoclave sterilization equip- 8 ment. Each tip 14 is sanitary during the manufacturing process 9 and is then packaged. A dentist selects a packaged tip, removes the tip from its package or visually inspects the tip 11 if it is already installed. The clear rigid plastic material 12 from which the tip is made allows visual verification of the 13 tip's sanitary state. If sterilization is required, such can *44* 14 be achieved during the manufacturing process by using any S 15 suitable sterilization process, such as gamma ray sterilizaj 16 tion.

17 The prior art metal tip comprised two concentric tubes S: 18 an inner water tube surrounded by an outer air tube. In 19 practice, the orifice at the end of the prior art metal tip can be quite irregular causing uneven spray when the air and 21 water flows are effected simultaneously. Uneven flows results 4*4* 22 in an unpredictable spray pattern.

S 23 The extruded tip 14 of the present invention yields very 24 uniform orifices for both air and water at the end 15 of the tip 14. This results in a uniform distribution of air, water 26 or spray. A continuous, uninterrupted air supply through 1 parallel air passageways 34 mitigates air turbulence and 2 therefore produces a more accurate and controlled spray.

3 The adaptor 20 is different from the prior art adaptors.

4 The tapered male connector 21 with the axial opening 48 provides a mounting location for the tip 14 and keeps the water 6 supply separate from the air supply until they are mixed 7 together at the end 15 of the tip 14 to form the spray. When 8 the air and water are activated simultaneously by the dental 9 operator, the continuous 360° air annulus 35 around the central water passage 32 combines to produce a fine spray.

11 An alternate embodiment of the present invention is shown 12 in Figure 9. The adaptor 120 is a conventional adaptor used 13 in a conventional all-metal dental syringe assembly. The 14 adaptor 120 has a first set of threads 142 for attaching the adaptor 120 to the threaded opening 13 in the handpiece body 16 12 (Figure The adaptor 120 has a second set of threads 17 144 which cooperate with tho threads in nut 28 (Figure 1) to 18 seal the tip 114 to the adaptor 120. A plurality of circum- 19 ferentially-disposed channels 1.62 (only one shown) are provided in the body of the adaptor 120 to allow air from the handpiece 21 body 12 to pass to the hollow interior of the tip 114.

22 The syringe tip.114 is similar to the tip 14 shown in .o 23 Figures 2-4. The tip is fabricated from rigid plastic material 24 and has the same internal cross-section configuration shown in Figures 3 and 4. The tip 114 has a tip extension 113 formed 26 integrally with the tip 114 at the entrance end of the tip 1 114. The tip extension 113 extends through an axial opening 2 148 in a baffle 146 that extends across the interior of the 3 adaptor 120. The adaptor 120 at its end 157 has an insert 4 portion to accommodate an annular rubber sealing ring that surrounds that tip extension 113.

6 In the preferred embodiment, the outer diameter of the 7 tip extension 113 is in the range generally of .062" .066", 8 and most preferably is approximately .064". The length of the 9 tip extension 113 is in the range generally of .012" .032", and most preferably has a length of approximately .022" 11 The tip extension 113 has a hollow central channel 117 12 that allows water from the handpiece body 12 to pass into the S: 13 central passageway 32 of the tip 114.

S14 Figure 10 shows in cross-section a coupling device 180 used in connection with an alternate embodiment of the present 16 invention. The coupling device 180 comprises a mounting stem 17 184 having an expanded shoulder 186 and an interior hollow 18 member 182.

19 The coupling device 180 in use is shown in Figure 11.

S 20 A conventional adaptor 120 (having the same elements as de- 21 scribed with reference to Figure 9) has a coupling device 180 22 mounted therein. The mounting stem 184 of the coupling device S 23 180 is positioned in the axial opening 148 of the baffle 146 24 and is held in place by an annular rubber sealing ring 125.

The expanded shoulder 186 of the coupling device 1P3 fits 26 against the interior wall of the baffle 146. A plastic syringe 1 tip 214 is press fit onto the interior hollow member 182 of 2 the coupling device 180. Water from a handpiece body 12 is 3 directed down the hollow passageway 187 in the coupling device 4 180 to the central passageway 232 of the tip 214. The expanded shoulder 186 does not block the air passageway 162 that pro- 6 vides air to the air passageways 234 in the tip 214.

7 In the preferred embodiment, the overall length of the 8 coupling device 180 is in the range of generally .815" .835", 9 and most preferably has a length of approximately .825". The coupling device 180 has a mounting stem 184 that has a length 11 in the range of generally .165" .185", the expanded shoulder 12 186 has a length in the range generally of .020" .030" and 13 the hollow tip member 182 has a length in the range generally 14 of .615" .635". In the most preferred embodiment, the 15 mounting stem has a length of approximately .025" and the .o 16 hollow tip member has a length of approximately .625".

17 Other advantages inure from the use of plastic as the 18 material from which the tip 14 is fabricated. A plastic tip 19 will transmit less heat and cold to sensitive tissues in the oral cavity. Plastic tips are not electrically conductive and 21 will not transmit a spark which can occur during modern dental 22 treatments using electro- surgical devices. Also plastic tips 23 are not harmed by the presence of ultrasonic devices.

24 The tip 14 is fabricated from a good quality, rigid plastics The bend 17 in the tip 14 is provided during a heat 26 forming step and once the plastic has cooled, the bend is a 1 permanent part of the rigid tip 14. The entire tip fabrication 2 process including extruding the plastic with the central water 3 passage 32 and the arcuate section air passages 34, cutting 4 the plastic.extrusion to length, heat forming the bend 17, diecutting the continuous 360° air annulus 35 and forming the 6 resilient O-ring seal 60 is performed in a special multiple 7 operation machine.

8 While the invention has been illustrated with respect to 9 several specific embodiments thereof, these embodiments should be considered as illustrative rather than limiting. Various 11 modifications and additions may be made and will be apparent 12 to those skilled in the art. Accordingly, the invention should S 13 not be limited by the foregoing description, but rather should 14 be defined only by the following claims.

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Claims (9)

1. A syringe tip adaptor for connecting a syringe tip to a handpiece body, the syringe tip adaptor comprising: a) a generally cylindrical body having a hollow interior, o0 exCy¥ernor sorrcce o-P +ke cylin,k coA b6o-A b) first meanskfcr securing the cylindrical body to the handpiece body, c) channel means for providing an air passage from the handpiece body through the cylindrical body and into an air passageway in the syringe tip, the channel means being dispos&d relative to the hollow interior of the cylindrical body, d) a baffle mounted within the hollow interior of the cylindrical body, the baffle including an axial opening, and e) an elongated tapered male connector formed integrally with the baffle and having an axial opening therethrough adapted to cooperate with a central passageway in a syringe tip to provide a water passageway from the handpiece through the adaptor and into the syringe tip whereby when a syringe tip is mounted on the tapered male connector the syringe tip will be tightly held on the tapered male connector to prevent axial rotation of the syringe tip and to ensure that the air and water passageways do not leak into each other.

2. The adaptor of claim 1 further including a rounded shoulder surrounding the tapered male connector at the location where the male connector joins the baffle to provide a sealing surface when the syringe tip is mounted on the male connector and, to provide access for air to enter into air passageways in the syringe tip while at the same time preventing water from leaking out of a water passageway in the syringe tip.

3. The adaptor of claim 1 or claim 2 wherein the channel means comprises a plurality of channels disposed circumferentially around the cylindrical body.

4. The adaptor of any one of claims 1 to 3 wherein the first means comprises first screw threads on the exterior 0693k/lfg *r S r 17 surface of the cylindrical body.

The adaptor of any one of claims 1 to 4 wherein a forward interior portion of the cylindrical body is provided with an hexagonal cross-section for using an allen wrench to connect the adaptor to the handpiece.

6. The adaptor of any one of claims 1 to 5 further comprising second means for connecting the cylindrical body to a nut to seal the syringe tip to the adaptor.

7. The adaptor of claim 6 wherein the second means comprises second screw threads on the exterior surface of the cylindrical body. syrne ,ssemby .r

8. A dental syringe assembly comprising a handpiece body 1 including means for mounting a& syringe tip assembly to the handpiece body, said syringe tip assembly comprising: a) a syringe tip adaptor for connecting a syringe tip to a handpiece body comprising: 1) a generally cylindrical body having a hollow interior, 2) first screw threads on the exterior surface of the cylindrical body for connecting the cylindrical body to the handpiece body, 3) channel means for providing an air passage from the handpiece body through the cylindrical body and into an air passageway in the syringe tip, the channel means being disposed relative to the hollow interior of the cylindrical body, 4) a baffle mounted within the hollow interior of the cylindrical body, the baffle including an axial opening, and an elongated tapered male connector formed integrally with the baffle and having an axial opening therethrough adapted to cooperate with a central passageway in a syringe tip to provide a water passageway from the handpiece through the adaptor and into the syringe tip whereby when a syringe tip is mounted on the tapered male connector, the syringe tip will be tightly held on the tapered male connector to prevent axial 0693k/lfg 18 rotation of the syringe tip and to ensure that the air and water passageways do not leak into each other, and b) a syringe tip mounted on the syringe tip adaptor.

9. A syringe tip adaptor, substantially as herein described with reference to the drawings. A dental syringe assembly, substantially as herein described with reference to the drawings. DATED this 11th day of September, 1992. WARREN L. DAVIS and DAVID R. WASSERMAN By Their Patent Attorneys DAVIES COLLISON CAVE B. B B B B* 0 B. A lB 0693k/lfg ABSTRACT A syringe tip adaptor (20) for cGnecting a syringe tip (14) to a handpiece body the syringe tip adaptor (14) comprising; a generally cylindrical body having a hollow interior, first means (42) for connecting the cylindrical body to the handpiece body, a baffle (46) mounted within the hollow interior of the cylindrical body, and a tapered male connector (21) formed integrally with the baffle (46) and having an axial opening (48) therethrough. *ee o SS o S S