Liquid admixing apparatus for dental water-injection systems

Liquid admixing means for a dental oral water-injection system are provided for introducing an additive liquid from a reservoir through an additive tube into a water conduit in the water-injection system wherein a valve in the additive tube can be opened and closed remotely by manually operable means.

BACKGROUND OF THE INVENTION 
Dental patients undergoing drilling are often subjected to unpleasant oral 
ordors of which the principal sources are dislodged decayed tooth 
structure and food materials. Restorative materials used in the dental 
procedure also exhibit odors which are at least unusual and unfamiliar to 
the patient if not actually unpleasant. The sum effect of the various 
odors to which a patient is subjected during treatment is unsettling and 
must be counted among the factors making relaxation difficult and 
contributing materially to a negative preception of dental treatment. 
It is a principal purpose of the present invention to mask the odors to 
which a patient is exposed during drilling. This is accomplished by means 
of liquid admixing appratus which permits a fragment oral freshener liquid 
to be introduced into the water stream injected into the patient's mouth 
from a conventional high-speed dental handpiece. The fragrant oral 
freshener additive relieves the patient from exposure to unpleasant odors 
and allows the patient to have a fresher taste at the end of the dental 
treatment. 
The invention also has as an object the provision of a device allowing for 
introduction into the water entering the patient's mouth of a liquid which 
aids in the tooth drilling process. It has been discovered that the 
presence of certain liquids added to the water directed onto a tooth 
during drilling markedly reduces the time required to carry out a given 
drilling operation. These additive liquids include solutions containing 
fatty oils such as glycerol, and such solutions may also include the 
deodorizing ingredients mentioned previously so that the freshening effect 
is achieved as well. 
Various devices have been known heretofore for injecting liquids other than 
water into the mounth of a patient during dental treatment. Thus medicinal 
liquid is injected by the apparatus of U.S. Pat. No. 3,164,153, cleansing 
agents are injected by the apparatus of U.S. Pat. No. 4,220,446, and 
various liquid agents are injected by the apparatus of U.S. Pat. No. 
3,144,867. In none of these prior art disclosures however is a liquid 
additive introduced into the water conduit of a dental oral 
water-injection system so that an admixture of the additional liquid plus 
the water enters the patient's mouth. 
SUMMARY OF THE INVENTION 
Liquid admixing apparatus is provided in accordance with the invention for 
use with a dental oral water-injection system including a water conduit 
connected to a handpiece. The apparatus comprises an additive tube 
connectable at a first end portion with the water conduit. A reservoir is 
provided for containing an additive liquid and with which an oppsoite 
second end portion of the additive tube communicates. Between the first 
and second additive tube end portions a valve is included for controlling 
additive flow therethrough. Pressure differential means are provided for 
creating a lesser pressure in the additive tube than in the reservoir. 
Manually operable means are also provided for remote operation of the 
valve. By this apparatus the valve can be opened to cause flow of the 
additive liquid from the high pressure reservoir through the lower 
pressure additive tube for admixture with water in the oral 
water-injection system. 
In one preferred embodiment of the invention the pressure differential 
means is a superatmospheric pneumatic pressure source acting on the 
contents of the reservoir so that the additive liquid is forced into the 
water conduit. In another embodiment the pressure differential means is a 
venturi in the water conduit so that sucction accomplishes the admixing. 
In either case a filter may be provided on the second end portion of the 
admixture tube communicating with the reservoir and a removable lid may be 
provided on the reservoir. 
One preferred valve comprises a valve body defining a first chamber with 
which the admixture tube first end portion communicates and a second 
chamber with which the admixture tube second end portion communicates. The 
valve further includes a diaphragm in the valve body defining part of the 
first chamber and a partition in the valve body separates the first and 
second chambers. A valve seat is in an opening in the partition and a stem 
valve connected to the diaphragm is spring-biased into closed position on 
the seat. The diaphragm is displaceable by the manually operable means for 
remote operation of the valve. 
The preferred manually operable means is pneumatic and comprises a 
pneumatic pressure line connecting the valve with a compressed air source. 
A needle valve in the pressure line is spring-biased into closed position. 
Cam means are included for opening the needle valve and effecting remote 
operation of the valve.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring first to the embodiment of FIGS. 1 to 4, a dental oral 
water-injection system 10 includes a water conduit 11 connected to a 
handpiece 12 through a low-pressure venturi tube 13. The venturi tube is 
of tapered construction which causes an increase in the velocity of flow 
of liquid therethrough and a corresponding decrease in fluid pressure, 
thus creating a suction effect. During a drilling procedure water is 
injected into the patient's mouth through the handpiece 12. 
As noted previously drilling procedures typically dislodge tooth structure, 
both decayed and not, and also food materials, all of which produce 
unpleasant odors. The restorative materials used in the procedure also 
have distinct odors which if not unpleasant are at least unfamiliar to the 
patient. It is one general purpose of the present invention to mask such 
odors by introducing into the water which is injected into the patient's 
mouth a fragrant liquid freshener. 
To this end an additive tube in the form of a suction tube is connected to 
the venturi 13 at a first suction tube end portion 15. An opposite second 
end portion 16 of the suction tube communicates with a reservoir 17 shown 
in more detail in FIG. 2. Thus the reservoir 17 includes a cylindrical 
open-topped canister 18 threaded about its upper periphery to receive a 
screw-type lid 19. The lid 19 is provided with a screened vent 20 and a 
central hole through which the second suction tube end portion 16 extends 
downwardly. The lower open end of the suction tube end portion 16 is at a 
low level of the canister 18 and is equipped with a filter 21. The 
canister 18 may be unscrewed from the lid 19 and filled with a selected 
oral freshener liquid which can be withdrawn by suction through the 
suction tube second end portion 16. The screen on the vent 20 and the 
filter 21 both prevent foreign material from entering the water-injection 
system and hindering flow in the handpiece 12. Also the screened vent 20 
permits the level of the freshener liquid in the canister 18 to be at 
atmospheric pressure. 
Referring now to FIG. 3, a valve 23 is shown which includes a cylindrical 
valve body 24 defining a first chamber 25 and a second chamber 26. The 
suction tube first end portion 15 communicates with the first chamber 25 
and the suction tube second end portion 16 communicates with the second 
chamber 26. The two chambers are separated by a partition 28. At the 
opposite end of the first chamber 25 remote from the partition 28 is a 
flexible diaphragm 29 of elastomeric material. A valve stem 30 is attached 
to the diaphragm 29 by a mount 31 and passes through an over-large central 
hole ina stop element 32 within the first chamber 25. A compression spring 
33 is disposed axially about the stem 30 and is biased between the mount 
31 and the stop element 32. 
At the end of the valve stem 30 remote from the mount 31 is a valve head 
which operates between open and closed positions on an annular surface 
about a central hole in the partition 28 the annular surface constituting 
a valve seat. The valve head 35 and valve seat are both in the second 
chamber 26. The valve body 24 also defines a pneumatic pressurizing 
chamber 37 on that side of the diaphragm 29 opposite the first valve 
chamber 25. It will be apparent that an increase in pressure within the 
pressurizing chamber 37 will cause the diaphragm to flex inwardly into the 
first valve chamber 25 and move the valve stem 30 to the left as shown in 
FIG. 3 so that the valve head 35 lifts off of the valve seat on the 
partition 28 and thereby opens communication between the first valve 
chamber 25 and the second valve chamber 26. This movement of the valve 
compresses the spring 33 between the mount 31 and the stop 32. When the 
pressure in the chamber 37 is reduced the spring 33 expands and moves the 
head 35 of the valve back to closed position on the valve seat. 
A pneumatic pressure line 38 connects the pressurizing chamber 37 with a 
compressed air source 39. As shown in FIG. 4 manually operable pneumatic 
means 40 is provided for remote operation of the valve 23. These means 
include a cylindrical housing 42 which defines a chamber 43. Through a 
hole 44 the end of the pneumatic pressure line 38 communicates with the 
chamber 43. A needle valve 45 mounted on a stem 46, which passes through a 
stop element 47, is arranged to open and close the hole 44. At the 
opposite end of the stem 46 it is connected to a plunger 48 axially in 
slideable but in air-sealed relation with the interior of the housing 42. 
A compression spring 50 is biased between the plunger 48 and the stop 
element 47. At the extreme end of the housing 42 is a cam 51 pivoted about 
an axle 52 and having a manual actuator arm 53. The cam 51 is configured 
such that when it is turned by the actuator arm 53 about the axle 52 it 
urges the plunger 48 to the left as shown in FIG. 4 to compress the spring 
50 and cause the needle valve 45 to seat within and seal the hole 44 
opening into the pressure line 38. By turning the actuator arm 53 in an 
opposite direction, the plunger 48 is moved to the right at shown in FIG. 
4 by the compression spring 50 to withdraw the needle valve 45 from the 
hole 44 and thus cause the pressure line 38 to be in communication with 
the chamber 43. In this manner bursts of compressed air are permitted to 
pass from the compressed air source 39 through the pressure line 38 by 
selective operation of the actuator arm 53. Thus the pressure in the 
pressurizing chamber 37 behind the diaphragm 29 can be changed to operate 
the valve 23 as described previously. 
By means of the foregoing apparatus a dentist may have on hand at a 
convenient place a supply of oral freshener liquid in the reservoir 17. 
Within easy reach of the dentist and perhaps remote from the reservoir 17 
is the manually operable cam means for operating the valve 23. When 
desired the dentist may introduce a selected amount of oral freshener 
liquid into the patient's mouth through the high-speed handpiece 12 by a 
simple turning of the actuator arm 53. 
It will be evident from the foregoing description of the embodiment of 
FIGS. 1 to 4 that the relatively low subatmospheric pressure in the 
venturi 13 and the relatively high atmospheric pressure acting on the 
additive liquid in the cannister 18 through the vent 20 produce a pressure 
differential which causes the additive liquid to be drawn into the water 
conduit by suction. In the preferred embodiment of the invention 
illustrated in FIG. 5 the pressure differential means is a 
superatmospheric pneumatic pressure source acting on the additive liquid 
in the reservoir so that the additive liquid is forced into the water 
conduit. More particularly, the embodiment of FIG. 5 includes a dental 
oral water-injection system 60 which includes a water conduit 61 connected 
to a handpiece 62. Water is injected into the patient's mouth through the 
handpiece 62 during a drilling procedure. 
An additive tube is connected to the water conduit 61 at a first additive 
tube end portion 63. A special Y-fitting 64 is employed to interconnect 
the water conduit 61 with the additive tube first end portion 63, the legs 
of the Y-fitting being attached to the respective conduit 61 and tube 
portion 63 with an acute included angle between the legs. Preferably this 
included angle is approximately thirty degrees. Such a connection is 
superior to a right angle T-fitting because less turbulence is created and 
the two streams merge into one more evenly. 
A valve 65 is provided which is of the same construction and function as 
the valve 23 in the embodiment of FIGS. 1 to 4. A pneumatic pressure line 
66 similar to the pressure line 38 in the previous embodiment connects the 
valve 65 with manually operable penumatic means 67 which are identical to 
the pneumatic means 40 of the prior embodiment. As before the pneumatic 
means 67 is connected with a compressed air source 68. 
A second end portion 70 of the additive tube extends from the valve 65 
opposite the first end portion 63. The second end portion 70 communicates 
with a reservoir 71 which comprises a cylindrical open-topped cannister 72 
threaded about its upper periphery to receive a screw-type lid 73. The 
second end portion 70 extends downwardly into the cannister 72, perhaps 
with a filter at its lower end, in a manner similar to the construction 
shown in FIG. 2. 
Instead of a vent on the lid 73 of the reservoir, the reservoir 71 includes 
a pressurizing tube 75 which extends through the lid 73 in sealed relation 
thereto. Compressed air in a bottle 76 (or other suitable source) passes 
through a pressure regulator 78, the purpose of which is to accurately 
control the output pressure at a given superatmospheric level. in the 
pressurizing tube 75 and into the reservoir 71. 
As mentioned previously the additive liquid used in the embodiment of 
either FIGS. 1 to 4 or the embodiment of FIG. 5 may be a liquid which 
includes a oral freshener component. Alternatively the additive liquid may 
include a drill lubricant component, either alone or in combination with 
the oral freshener component. It has been observed that certain oral 
freshener liquids contain fatty oils such as glycerol. It has also been 
observed that when such liquids are added to the water stream injected 
into the patient's mouth during drilling the operation of the drill is 
much more efficient and can be carried out in substantially less time. For 
example the drilling time for a crown preparation could be significantly 
decreased when a mouthwash glycerol is added to the water-injection stream 
by means of one of the forms of apparatus of the invention. Patient chair 
time can be dramatically reduced by utilizing the apparatus of the 
invention to introduce into the water entering the patient's mouth a 
liquid which aids in the tooth drilling process as described. 
The scope of the invention is to be taken from the following claims rather 
than from teh preceding description of preferred embodiments.