Dental needle with stick resistant protective sleeve

A protective device for a dental needle is disclosed. The device comprises a generally cylindrical sleeve having therein a sliding hub assembly adapted to receive a dental syringe having a cannula with distal and proximal ends and generally rectangular openings in the walls thereof. The hub assembly includes locking means extending through the generally rectangular openings to retain the syringe in a retracted position. The sleeve extends over and covers both the distal and proximal ends of the cannula when the sleeve is in a retracted position so as to protect the dental health professional from contact with the needle.

BACKGROUND OF THE INVENTION 
The invention of this application relates to a dental needle having a stick 
resistant protective sleeve. More particularly, this invention relates to 
a protective device for a dental needle which protects the dentist from 
contact with the needle when giving an injection. 
In recent years, the dental health professional has become increasingly 
aware of the hazards associated with an accidental needle stick during 
resheathing of the needle after an injection has been given. It has been 
found that numerous diseases, such as AIDS and hepatitis, can be 
transmitted in this fashion. 
Protective sleeves for hypodermic needles have been previously suggested. 
McFarland, U.S. Pat. No. 4,772,272, describes a protective sleeve which 
overlies needle support means and a portion of the syringe in both its 
needle protection position and its needle injection position. The 
protective sleeve is positively but releasably retained in both such 
positions. By retaining the sleeve in the needle injection position with 
the needle exposed, the chances of the dental health professional being 
accidentally stuck with the needle are increased significantly. 
Craig, U.S. Pat. No. 2,925,083, describes a hypodermic syringe having 
means, such as a hood, for concealing and guarding the hypodermic needle 
until the syringe is in position for use. 
Mitchell, U.S. Pat. No. 4,631,057, describes an apparatus for injecting a 
substance into a human comprising a body, a needle coupled to the body and 
terminating in a point and a needle guard mounted on the body, for 
movement from a retracted position in which the guard does not shield the 
needle to an extended position in which the guard does shield the needle. 
The needle guard can be releasably retained in the retracted position and 
locked in the extended position. The locking of the needle guard is 
accomplished by interlocking members carried by the needle guard and by a 
collar mounted on the body. 
Harbaugh, U.S. Pat. No. 4,655,751, describes a liquid dispensing and 
receiving syringe which includes an elongated cylindrical transparent 
container open at its front and rear ends and defining a central cavity 
for holding liquid. A rearwardly extending plunger is slideably secured in 
the rear end of the cavity for dispensing liquid out the front end of the 
container and through a hollow needle secured to the container front end 
for transporting liquid into the cavity from the needle. A concentric 
protective shell is connected to and spaced outwardly from the container 
sidewall and is slideable between a first needle exposing position and a 
second needle covering position. 
Fox, U.S. Pat. No. 4,695,274, describes a safety needle attachment for a 
syringe body assembly which makes use of a needle holder with a needle 
fixed in the holder. The needle is initially surrounded by a protective 
jacket which is releasably interlocked with the holder. When the needle is 
to be used, the interlock is released and the jacket is telescoped over 
the holder to project the needle through a membrane over the end of the 
jacket to a working position. 
Haber et al., U.S. Pat. No. 4,767,413, describes a disposable dental 
syringe having a prefilled ampule of liquid in a double-ended hypodermic 
needle arranged and spaced in axial alignment with the ampule. The ampule 
is moveable axially through the cylinder of the syringe until the proximal 
end of the needle penetrates the ampule and the distal end of the needle 
extends outwardly from the cylinder for administering an injection. The 
ampule is locked in the distal position so that an injection may be 
administered. Upon completing the injection, the ampule is released from 
the distal position and moved proximally through the cylinder, so that the 
distal end of the needle is automatically retracted within the cylinder. 
Heretofore, none of the dental needles incorporating protective sleeves 
have adequately protected the dental health professional from accidental 
contact with or puncture by the needles. The invention disclosed herein 
comprises a protective device for a dental needle which does protect the 
dental health professional from contact with the needle. 
SUMMARY OF THE INVENTION 
The present invention contemplates a protective device for a dental needle 
to be administered to human subjects to protect the administrator from 
contact with the needle. 
In one aspect of the present invention, the protective device of the 
invention comprises a generally cylindrical sleeve having therein a 
sliding hub assembly adapted to receive a dental syringe having a cannula 
with distal and proximal ends and generally rectangular openings in the 
walls thereof. The hub assembly includes locking means extending through 
the generally rectangular openings to retain the syringe in a retracted 
position so that the protective sleeve extends over and covers both the 
distal and proximal ends of the cannula when the sleeve is in a retracted 
position. 
In a further aspect of the present invention, the locking means of the 
protective sleeve of the invention are releasable to allow the hub 
assembly to slide within the sleeve to thereby extend the distal end of 
the cannula through a centrally positioned opening in the top end of the 
sleeve to facilitate injection of the needle in a subject. 
In another aspect of the present invention, the protective sleeve of the 
invention has top and bottom ends adapted to receive sealing means. 
The present invention provides several benefits and advantages. 
One benefit of the present invention is that the protective sleeve of the 
invention protects the administrator from contact with dental needles. 
Another benefit of the present invention is that the ends of the protective 
sleeve of the invention are sealed to prevent tampering with the dental 
needle. 
One of the advantages of the present invention is that the protective 
sleeve of the invention eliminates the need for the dental health 
professional to resheath a dental needle after its use. 
Another advantage of the present invention is that the protective sleeve of 
the invention extends over and covers both the distal and proximal ends of 
the cannula or needle when the sleeve is in a retracted position and the 
cannula or needle is exposed only during injection. 
Other benefits and advantages of the present invention will become readily 
apparent to those skilled in the art from the following detailed 
description of the invention, the drawings and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention is directed to a protective device for a dental 
needle to be administered to human subjects to protect the administrator 
from contact with the needle. 
With reference to FIGS. 1-4, a preferred embodiment of the protective 
device of the present invention is shown. Protective device 10 comprises a 
generally cylindrical sleeve 12, constructed of a plastic material. Sleeve 
12 has disposed therein a sliding hub assembly 14 which is adapted to 
receive a dental syringe 16 which has a cannula or needle 18 with a distal 
end 20, which is used for injections, and a proximal end 22. The sleeve 12 
also has a plurality of horizontal, generally rectangular openings 24 and 
vertical, generally rectangular openings 25 in the walls thereof. 
Hub assembly 14 includes a plurality of locking means or tabs 26 which 
extend through the generally rectangular openings 24 to thereby retain the 
syringe 16 in a retracted position. When the sleeve 12 and the syringe 16 
are in such a retracted position, the sleeve 12 extends over and covers 
both the distal end 20 and the proximal end 22 of the cannula 18 to 
protect the dental health professional who will administer an injection 
with syringe 16 from any contact, accidental or otherwise, with the 
cannula or needle 18. 
The sleeve 12 has a top end 28 and a bottom end 30. The bottom end 30 is 
open to the full diameter of the sleeve to permit passage of syringe 16 
into sleeve 12 to engage hub assembly 14. Top end 28 has a centrally 
positioned opening 32 having a diameter of about one-third the diameter of 
the cylindrical sleeve 12. 
As illustrated in FIG. 7, the top end 28 is adapted to receive a top 
sealing means or cap 34 which fits into centrally positioned opening 32. 
Cap 34 is preferably tamper indicative to maximize safety of the device to 
the user and patient. Bottom end 30 is also adapted to receive a bottom 
sealing means or cap (not shown) which is a flat, circular piece having 
the same outside diameter as the sleeve 12. Perpendicular to the flat 
portion is a circular ridge which has an outside diameter the same as the 
bottom inside diameter of the protective sleeve 12. Top sealing means 34 
and the bottom sealing means may preferably be interconnected by a strap 
or other suitable connecting means. 
The syringe 16 is fabricated of stainless steel, as is well known in the 
art, as is the cannula or needle 18. The syringe 16 has a cavity 36 
adapted to receive a carpule containing the anesthetic or other medicament 
to be administered to a patient by injection. Cannula 18 is affixed by 
means of epoxy or other suitable adhesive well known to those of skill in 
the art to an inner sliding hub 38 which is threaded to engage hub 
assembly 14 at its threaded portion 40 as shown in FIGS. 4-6. 
The locking means 26 of hub assembly 14 are releasable to allow hub 
assembly 14 to slide upwards within sleeve 12. In this manner, the distal 
end 20 of cannula 18 passes through an opening 42 in hub assembly 14 and 
is extended through centrally positioned opening 32 in the top end 28 of 
sleeve 12 to facilitate injection of cannula 18 in a subject or patient. 
In operation, the sterile dental syringe 16, loaded in its cavity 36 with 
an anesthetic carpule, is inserted into the bottom end 30 of the 
protective sleeve 12 until it stops. The protective sleeve 12 is then 
rotated clockwise until threaded portion 40 is threaded onto syringe 16. 
When an injection is to be made, top cap 34 is removed, then, the dental 
health professional holds sleeve 12 between thumb and forefinger at the 
point where the locking means 26 extend through the openings 24, which is 
about two-thirds of the length of sleeve 12, from top end 28 to bottom end 
30. The locking means 26 are then depressed releasing hub assembly 14. The 
syringe 16 is pushed through sleeve 12 to extend needle 18 through opening 
32 and the injection is made. 
When the injection is complete, the protective sleeve 12 is held firmly by 
the dental health professional between thumb and forefinger. The syringe 
16 is pulled back to retract needle 18 until locking means 26 are in their 
original position extending through openings 24 to lock sleeve 12 in a 
retracted position. While still holding protective sleeve 12, the dental 
health professional rotates sleeve 12 counter-clockwise until inner hub 38 
disengages from threaded portion 40 of hub assembly 14. Needle 18 is then 
removed from syringe 16 and disposed of by means well known in the art. 
The protective device of the present invention, when used properly as 
described above, virtually eliminates the possibility of the dental health 
professional sticking himself or herself during resheathing of the needle. 
The foregoing is intended as illustrative of the present invention but not 
limiting. Numerous variations and modifications may be effected without 
departing from the true spirit and scope of the invention.