Chemical apparatus and process disinfecting – deodorizing – preser – Process disinfecting – preserving – deodorizing – or sterilizing – Using sonic or ultrasonic energy
Reexamination Certificate
1999-11-10
2002-09-10
Warden, Sr., Robert J. (Department: 1744)
Chemical apparatus and process disinfecting, deodorizing, preser
Process disinfecting, preserving, deodorizing, or sterilizing
Using sonic or ultrasonic energy
C422S028000, C422S033000, C422S292000, C422S295000, C422S297000, C422S300000, C422S128000, C095S030000, C055S299000
Reexamination Certificate
active
06447718
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus and associated method for decontaminating contaminated matter such as objects and substances and, more particularly, to a pressurizable ultrasonic cleaner having an enhanced transient cavitation effect due to the addition of a volatile substance to a cleaning solution and pressurization thereof during the ultrasonic decontamination process.
BACKGROUND OF THE INVENTION
Infection control is essential to medical and dental practices. Indeed, the Center for Disease Control, medical associations, dental associations and various states are passing laws and guidelines to increase the infection control measures that must be taken by dentists and physicians. In particular, concerns over patient to patient or staff to patient transfer of various diseases and viruses such as hepatitis B virus, HIV and other diseases have been on the rise. It is believed that most disease transfer is primarily due to the continual reuse of instruments. Therefore, efforts to combat disease transfer have generally focused on sterilizing instruments through the use of one or more of six sterilants: steam, chemical vapor, dry heat, chlorine dioxide, ethyl oxide, glutaraldehyde-containing liquid, and formaldehyde. McErlene et al., “Assessment of the Effectiveness of Dental Sterilizers Using Biological Monitors”,
J. Can. Dent. Assoc.
58(6):481-83 (1992); B. Nystrom, “New Technology for Sterilization and Disinfection”, Amer.
Jrl. of Med.
91(3B):2645-2665(1991). However, the above-listed sterilants, alone and in combination, often fail to adequately, and space and cost effectively, provide a safe means for sterilization. McErlene et al., “Assessment of the Effectiveness of Dental Sterilizers Using Biological Monitors”,
J. Can. Dent. Assoc.
58(6):481-83 (1992);B. Nystrom, “New Technology for Sterilization and Disinfection”,
Amer. Jrl. of Med
91(3B):2645-65 (1991); and N. Skaug, “Proper Monitoring of Sterilization Procedures Used in Oral Surgery”,
Int. J. Oral Surg.
12:153-58 (1983).
The high percentage of sterilization ineffectiveness was highlighted in one alarming study that showed that 33% of the autoclaves used in general dental practice did not inactivate microbes. Simonsen et al., “An Evaluation of Sterilization by Autoclave in Dental Offices”,
J. Dent. Res.
58(A):Abstract No. 1236 (1979). And, in an even more alarming study of instrument sterilization procedures in oral surgery clinics, 23% of steam autoclaves; 50% of dry-heat oven sterilizers; and 100% of gas autoclaves did not kill biological spores. N. Skaug, “Proper Monitoring of Sterilization Procedures Used in Oral Surgery”,
Int. J. Oral Surg.
12:153-58 (1983).
Moreover, several other recent studies have shown that autoclave and heat sterilization routinely do not sterilize instruments. See Palenik, “Effects of Steam Sterilization on the Contents of Sharps Containers”,
Am. J. Infect. Control
, 21(1):28-33 (February 1993); Palenik et al., “Effectiveness of Steam Sterilization on the Contents of Sharps Containers”,
Clin. Prev. Dent.,
14(1:28-34 (January-February 1992); B. Nystrom, “New Technology for Sterilization and Disinfection”,
Am. J. Med.,
91(3B):264S-266S (Sep. 16, 1991); and Palenik et al., “Effectiveness of Steam Autoclaving on Bacterial Endospores Placed Within Five Types of Sharp Containers Was Tested”,
Am. J. Dent
3(6)239-44 (December 1990) of dental and medical instruments are not adequately decontaminated by various combinations of presoaking agents, dishwashers, ultrasonic cleaners, detergents and water. E. Sanchez & G. MacDonald, “Decontaminating Dental Instruments: Testing the Effectiveness of Selected Method”,
JADA
126:359-68 (March, 1995). In fact, the effective sterilization of many instruments has been so unreliable that instruments are being redesigned to facilitate effective cleaning and disinfection. Spach et al., “Transmission of Infection By Gastrointestinal Endoscopy and Bronchoscopy”,
Annals of Internal Medicine
118:117-28 (1993).
In addition to inadequate sterilization equipment, problems with sterilization methods also occur because of human error. Moreover, the expense and cost of safe effective sterilization techniques may force or otherwise influence the use of less effective sterilization techniques and equipment.
When properly applied, the ultrasonic cleaning process has been shown to be beneficial for deburring and debriding various instruments and tools. Ultrasonic energy consists of vibrations or sound waves above frequencies normally heard by the human ear. Typically, an ultrasonic generator is used to produce high frequency alternating electrical currents, which are transformed into mechanical ultrasonic vibrations by a transducer. The vibrations are then transmitted into liquids consisting of either water-based or solvent-type solutions which, in turn, contact the surfaces of the object to be cleaned. Thus, the ultrasonic energy engages the object via the liquid medium to remove contaminants therefrom and/or to destroy microbial matter.
Ultrasonic cleaning increases decontamination effectiveness to a level that is difficult to achieve by other means. Over the past several years, practical ultrasonic cleaning applications have grown rapidly. For example, it is known in the art that ultrasonic transient cavitation used in conjunction with germicidal solutions will kill microbes more quickly than will a similar solution in the absence of ultrasonic transient cavitation. R. M. G. Boucher, Ph.D., “Ultrasonics—A Tool to Improve Biocidal Efficacy of Sterilants or Disinfectants in Hospital and Dental Practice”,
Can. Jrl. of Pharmacology,
17(1):1-12 (1979). However, there are currently no methods employing ultrasonic vibration as the only means of decontaminating contaminated matter such as medical or dental instruments. In current processes, instruments or objects being decontaminated are typically moved from an ultrasonic cleaning device into an autoclave for further sterilization. “Decontamination” is used herein to encompass the broadest meaning of the term and includes, for example, deburring, debriding, sterilizing, or otherwise effecting cell disruption of contaminated objects, substances, or fluids.
A need therefore exists for an apparatus and method for decontaminating contaminated matter such as dental and medical instruments that is quiet, convenient, easy to use, inexpensive, and preferably heat-independent. It would further be desirable for the apparatus and method to operate at or near room temperature such that, for example, the “cold” sterilized instruments can be rinsed, dried off and used immediately after sterilization without having to first cool down the instruments. A need further exists for an apparatus and method of improving the efficiency of ultrasonic cleaning for decontaminating contaminated matter such as medical and dental instruments such that further sterilization processes are not required for acceptable decontamination.
SUMMARY OF THE INVENTION
The above and other needs are met by the present invention which, in one embodiment, provides an apparatus for decontaminating contaminated matter comprising a pressurizable container for containing the contaminated matter, a pressure source for pressurizing the pressurizable container to a predetermined pressure, a vibration source operably connected to the pressurizable container, and a cleaning solution contained within the pressurizable container and submerging the contaminated matter. Preferably, the cleaning solution comprises a base solution and a predetermined amount of a volatile substance that is more volatile than the base solution. The cleaning solution is then pressurized by the pressure source and vibrated by the vibration source to produce ultrasonic transient cavitation therein for decontaminating the contaminated matter. The contaminated matter may comprise, for instance, medical or dental instruments, or may comprise other substances such as, for example, a fluid. Further, the pressurizable container is capable of being pressurized to g
Carter Stephen Douglas
Cunefare Kenneth Arthur
Alston & Bird LLP
Carter Stephen Douglas
Soubra Imad
Warden, Sr. Robert J.
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