	Density
	(pounds per cubic foot)	1.5-3.0 lbs/ft³
	or
	(kilograms per cubic meter)	24.1-48.1 kg/m³
	Material Cell Count	12-20 cells/cm
	(cells per centimeter)
	Air Flow
	(cubic feet per minute)	0.1-5.0 ft³/min
	or
	(cubic decimeters per second)	0.05-2.4 dm³/sec
	25% IFD	121-198 lbf
	Indentation Force Deflection
	(pounds force)

It should be appreciated that although an exemplary foam is described in detail, the composition of suitable cushions may vary. For example, suitable foams for use in the present disclosure may have a different density, air flow, 25% indentation force deflection (IFD), compression force deflection (CFD), cubic feet per meter (CFM) rate, cell count, etc. Other characteristics, such as the compression force deflection (CFD), and/or tensile and/or tearing strength of a foam may also be considered. The foam characteristics, as described above, are included only for illustrative purposes and are not intended to include all suitable compositions forcushion14.

Generally, the foam characteristics may be balanced to achieve a suitable material for use in insertion and/or rotary cleaning of instruments. Selection of one or more of the density, material, and/or cell count of the foam may effect a change in the air flow, the indentation force deflection, the density, the compression force deflection, or other characteristics of the cushion. For example, selection of the appropriate material may include balancing the density and cell count of the foam, such that the foam functions as desired.

The “firmness” of the cushions may be measured using the 25% indentation force deflection (IFD) test according to the standard ASTM D 3574 Test B1: Specified Deflection. An IFD number represents the force required to indent a foam sample by a specified percentage (e.g. 25%) of its original thickness. As shown in TABLE 1 above, suitable foams have a 25% indentation force deflection of approximately 121 lbf to 198 lbf.

It further should be noted that the foam within the cushions may be described in relation to their cubic feet per minute (CFM) values. CFM values may be obtained by determining the cubic feet per minute air flow through a standard 15×15×4″ thick test piece of foam used in the IFD tests. As shown in TABLE 1 above, suitable foams have a CFM value of 0.1 ft³/min to 5.0 ft³/min (or 0.05 dm³/sec to 2.4 dm³/sec). Foams with other CFD values may be suitable as well.

In some embodiments, the cushion may be composed of polyurethane and/or urethane. The cushion may be composed of, and/or include, melamine. The cushion may comprise and/or be made from other types of materials, such as rubber, polyester, polyether, etc.

Polyurethane and/or urethane cushions may be able to withstand steam autoclaving without substantially deforming, melting, or producing any noxious out-gassing of toxic substances during the steam autoclaving process. Moreover, polyurethane is widely and safely used in many medical and dental applications.

As briefly noted above, in some embodiments, it may be desirable to sterilize the cushions (and the instruments) prior to use. For example, in many environments, steam autoclaving may be used to sterilize the cushions. Thus, the cushions may be configured to withstand sterilization via steam autoclaving prior to use. Due to the use of the cushions in medical and dental applications, the cushions typically may be configured to withstand steam autoclaving as performed in clinical environments, where the steam autoclaves typically operate within a range of between 275 degrees and 300 degrees F. and a range of between 20 psi and 30 psi.

The cushions may include an at least partially open-cell foam body. The at least partially open-cell body may allow steam from an autoclave to penetrate an interior region of the cushion. Penetration of the interior region enables steam to surround and effectively sterilize endodontic files or other instruments at least partially disposed within the cushion. Typically, substantially closed cell structures prevent steam from passing into the interior region of the cushion. Such closed cell cushions may not provide the necessary sterilization of the instruments positioned within the cushion. In contrast, cushions that have an air flow of more than approximately 1.0 dm³/second (as measured according to the standard ASTM D 3574 Air Flow Test G) may be adequate to enable sterilization of endodontic files positioned in the interior region of the cushion. As shown in TABLE 1, the cushions have an air flow of about 0.05 dm³/second to about 2.4 dm³/second.

Here, the cushion characteristics of the present disclosure have solved the grabbing, tearing and/or shredding problem found when contacting the prior art cushions with a rotating instrument for cleaning. For example, this is illustrated inFIG. 5, which shows thattip16 ofdrill15 lacks the torn offportions104 after being rotated in contact withcushion14 and withdrawn fromcushion14.Cushion14 may include some, all, or a combination of one or more of the following characteristics: a polyurethane open cell foam with an IFD range of 121-198 lbf, and/or a weight density range of 24.1-48.1 kg/m³, and/or an air flow In the range of 0.05-2.4 dm³/second and/or any other characteristics disclosed in TABLE 1, used to clean and store endodontic instruments, which may include rotary and/or hand endodontic instruments.

FIG. 6 schematically illustrates the instrument cleaning properties ofcushion14. Generally, the abrasive action of the foam in a cushion functions to substantially clean instruments inserted therein. More specifically, the porous material in the cushion is configured to grip an instrument, such as a dental instrument attached to a rotary drill (indicated generally asinstrument16 anddrill15 inFIG. 6). The gripping characteristics of the porous material substantially retains contaminants and other residuals from the instrument.

For example, during a medical or dental procedure, an instrument may accumulate contaminants (also referred to as bioburdens)44 that may cling to the file. For example, as shown in the left panel ofFIG. 6,contaminants44 may extend along the shaft ofinstrument16. Insertion ofinstrument16 intocushion14 may occur by penetrating the surface ofcushion14, as indicated by the downward arrow in the left panel.Drill15 may be rotatingfile16 before penetrating the surface.Drill15 may initiate rotation offile16 after penetrating the surface.

The middle panel ofFIG. 6 illustrates entry ofinstrument16 into an interior region ofcushion14.Contaminants44 may be sloughed off ofshaft16 asshaft16 rotates in thecushion14. The cells within the cushion are configured to substantially grip the file as it is inserted into and pulled out of the cushion. In some embodiments, the drill may be rotating at a speed of 100-1000 rotations per minute (RPM), though characteristics ofcushion14 may accommodate cleaning instruments rotating at an RPM outside this range.

In some embodiments, further cleaning ofinstrument16 may include the removal from and the reinsertion ofshaft16 to/intocushion14, thereby repeating the steps illustrated generally inFIG. 6. Multiple insertions of the dental instrument into the cushion may function to substantially decrease the level ofcontaminants42 oninstrument16. Hence,instrument16 may be rotated in a first pass, then removed fromcushion14. Instrument or file16 may then be re-inserted intocushion14 and rotated again for another pass. One to five passes may be desirable for different applications to ensure the file is clean, though the file may be inserted for more passes as needed.

In some embodiments,instrument16 is rotated incushion14 for about 1-3 seconds per pass. It is also possible to rotate for longer than 3 seconds, if needed. It is also possible to vary the time from pass to pass as desired.

In some embodiments, the rotational direction ofdrill15 may be varied as desired. For example, drill15 may rotateinstrument16 counterclockwise as shown inFIG. 6 before, during, and/or after the insertion and removal ofinstrument16 fromcushion14.Drill15 may rotateinstrument16 clockwise before, during, and/or after the insertion and/or removal ofinstrument16 fromcushion14.Drill15 may rotateinstrument16 with a mixture of counterclockwise and clockwise rotations as desired.Drill15 may rotateinstrument16 counterclockwise during a first pass and then clockwise during a second pass, etc. as desired.

By gripping the instrument as it is rotating in a cushion, the contaminants may be displaced from the instrument to the cushion. The composition of the cushion will affect the removal of contaminants from the instrument. Specifically, a foam having the characteristics found in TABLE 1 above may significantly reduce contaminants on an instrument.

As is shown in the right panel ofFIG. 6, removal ofinstrument16 fromcushion14 results incontaminants44 being left incushion14 as a result of the cleaning method.Shaft16 may be free or substantially free ofcontaminants44 and of torn off pieces ofcushion14 becausecushion14 was configured with characteristics such thatcushion14 would not tear, grab or shred upon contact with rotatinginstrument16.

FIG. 7 illustrates an embodiment of a cleaning method whereinstrument16 may be contacted to cushion14 by depressinginstrument16 horizontally against the outer surface ofcushion14 rather than insertinginstrument16 into the interior surface ofcushion14.Instrument16 may be rotated before, during, and/or after contact is made withcushion14. As shown,instrument16 is depressed betweenridges38 ofcushion14, butinstrument16 could also be depressed acrossridges38. The surface ofcushion14 could also be configured without ridges or in any formation desired.Instrument16 could be depressed onto the surface in any way desired.Cushion14 will grip and remove contaminents (such as contimanents44) fromcushion14.Instrument16 may be wiped on and/or swiped across the outer surface ofcushion14, and/or held in one position, during rotation ofinstrument16 while depressed againstcushion14.Cushion14 may have the characteristics described above that may allowcushion14 not to tear, grab or shred upon contact with rotatinginstrument16.

Instrument

16 may be rotated counterclockwise, clockwise, or a mixture of both directions, as desired, before, during, and/or after contact is made.Instrument16 may be contacted withcushion14 during rotation for 1 to 5 seconds, or for any length of time desired.Instrument16 may be removed and re-depressed ontocushion15 for 1 to 3 passes, or for as many passes as desired. The direction of rotation can be varied as desired during a pass and/or from pass to pass.

The method of inserting the instrument into the foam may be combined with the method of depressing the instrument horizontally against an outersurface of the foam as desired. One or the other could go first and then the method could be varied from pass to pass, such as by alternating if desired.

In some embodiments, a method may include providing a hand held polyurethane open cell foam with a 25% indentation force deflection (IFD) range of 121-198 lbf, and/or a weight density range of about 24.1-48.1 kg/m³, and/or an air flow in the range of about 0.05-2.4 dm³/sec used to clean and store endodontic instruments, which may include rotary and/or hand endodontic instruments, that cleans the rotating instrument by using a stabbing motion to pass the rotating instrument in and out of the polyurethane open cell foam one or multiple times. The method may include insertion of the instrument into the foam and/or depressing the foam horizontally against an exterior surface whileinstrument16 is rotating to clean the instrument.

Testing confirmed that using the insertion and depression methods with the cushions of the present disclosure did not result in grabbing, tearing, or shredding of the cushion by the rotating tips. Hence, the tips could be removed without foam portions remaining on the withdrawn file.

Testing also confirmed that contaminants can be successfully removed from the file to clean the rotating file using either the insertion or the depression method. Other testing also confirmed that a cleaning method involving inserting a rotating file into a cushion outperformed simply inserting a stationery file to clean. Other testing similarly confirmed that a cleaning method involving depressing a rotating file against the cushion outperformed depressing to wipe a stationery file across the cushion.

For example, the cushion of the present disclosure was found to clean more effectively than the prior art cushions using the traditional non-rotating stabbing method. A test was performed to gauge cleaning effectiveness, with the results illustrated in TABLE 2 below. Specifically, the cleaning effectiveness was measured using biological serial dilution techniques. Accordingly, the level of bioburdens (contaminants) on the instrument was measured prior to, and after insertion and removal (also referred to herein as a stab) of the instrument into and out of the cushion. As shown in TABLE 2 below, an 89.3% spore reduction level (level of bioburdens on the instrument) was achieved after a first stab of the instrument into the cushion of the present disclosure. A second stab increased the spore reduction level to 95.6%. A 97.4% spore reduction level was achieved after three insertions (or stabs).

TABLE 2

	Cushion of the	Prior Art Foam of U.S.
Foam	Present Disclosure	Pat. No. 8,231,734

Spore Reduction:	89.3%	82.6%
1 Stab
Spore Reduction:	95.6%	86.3%
2 Stabs
Spore Reduction:	97.4%	96.3%
3 Stabs

As is shown, the cushions of the present disclosure demonstrates improved spore removal compared to prior art cushions in the first two passes. The cushions of the present disclosure also demonstrate slightly improved performance with three stabs. The cushions of the present disclosure also removed almost as many spores in two stabs as the prior art cushion did in three stabs.

Other tests were performed to test the efficacy of the cushion of the present disclosure. For example, a test was performed to remove cement deposit from an instrument. The cement removal test mirrored the results of the spore removal test in that each pass with a given instrument provided better cleaning. All instruments passed the cleaning thresholds of the cement removal test with three stabs into foam of the present disclosure. Cushions having an IFD in the range of 161-173 lbf cleaned files in just two stabs. Cushions having an IFD of 156 lbf had one file clean in two stabs and one file clean in three stabs.

The cushions of the present disclose may provide several advantages over the prior art cushions. For example, the cleaning properties of a cushion in contact with a rotating instrument may be greatly enhanced because it takes less time to clean the instrument and contaminants are greatly removed while the instrument is moving in a rotary fashion in the cushion. This means the instrument may be cleaned without removing the rotary bit from the drill. Another advantage may be that rotating instruments that are vertically inserted in the cushion may not tear or shear the cushion, which nearly eliminates the chance of introducing cushion debris to an instrument and potentially introducing such debris back into the tooth. Another advantage may be that that the structural features of the cushion may help it load into and conform better to the socket-member. This may help eliminate the dislodgement during the use of loading and cleaning of all instruments, particularly rotary instruments, which may be due to the firmness and compressive pressure the inserted cushion exhibits against the walls of the cup. Another advantage may be that the cushion does not tear during horizontal cleaning as the cushion is much more tear resistant than prior art cushions, such as the prior art cushion. Another advantage may be that stationary or hand instruments may also be cleaned better using the cushion of the present disclosure.

Another advantage may relate to deformation as the cushion of the present disclosure may not deform under normal autoclave processing (heat) and thereby the loading and retention performance of the cushion as it is seated in the socket-member may not be compromised. In an autoclave the cushion of the present disclosure was stiff enough to resist significant deformation when placed under a load. The prior art cushion did not rebound.

In an embodiment of the present disclosure, a porous material, such as a foam cushion, is provided for insertion and/or rotary cleaning of instruments, including hand and rotary instruments. Such porous material may include an at least partially open-cell foam body and a surface. The porous material may be configured to substantially grip the instrument to remove a substantial portion of the contaminants from the instrument while the instrument is rotating and in contact with the porous material, but while not tearing, gripping, or shredding the porous material while rotating in contact with the porous material.

While the present description has been provided with reference to the foregoing embodiments, those skilled in the art will understand that many variations may be made therein without departing from the spirit and scope defined in the following claims. The description should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. The foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application. Where the claims recite “a” or “a first” element or the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring, nor excluding, two or more such elements.