292 Theories and techniques of oral implantology

well as numerous implant instruments and the implants themselves.

Dry heat sterilizers may require a temperature of 320° F. for 1 hour to destroy the same bacteria that can be destroyed by wet heat in a shorter time at a lower temperature. Dry heat sterilization, how-ever, is useful for powders, oils, plaster of Paris, and all other materials that cannot be permeated with moisture.

Bead sterilizers are another type of dry heat sterilization (Fig. 7-83). In this method the object to be sterilized is placed in tiny hot beads for approximately 30 seconds. It is useful for implants, and neither the cutting edges nor the temper of any instrument is damaged in the process.

Boiling is one of the oldest methods for sterilization. The instruments, which should be cleaned thoroughly and unclamped before being placed into the boiling water, are left there for at least 20 minutes. However, it has been shown that heat-resistant bacterial spores can withstand boiling water for many hours. The use of boiling water for the sterilization of instruments has been outmoded, and its use in the dental office should be discouraged.

Cold, or chemical, sterilization

Cold sterilization is used mostly for cutting instruments, such as scalpels, scissors, chisels, burs, and other tools that ordinarily become blunted if boiled. These instruments may be immersed in such solutions as nitromersol, benzalkonium chloride solution, polyethoxy polypropoxy ethanol-iodine, formaldehyde preparations, or 70% to 90% isopropyl alcohol for at least 30 minutes.

The Council on Dental Therapeutics of the American Dental Association feels strongly enough about the chemicals used for disinfecting instruments that they have required certain information to be included in the labeling, advertising, or packaging inserts of the various chemicals. The following points are emphasized and should be followed when using a chemical solution:

1. Adequate physical cleansing of instruments prior to disinfection is necessary.

2. An adequate margin of safety must be allowed in the recommended period of contact between the instruments and the disinfecting agent. Disinfection should take place in a suit-able container.

3. The disinfecting agent must be periodically replaced.

Chemical solutions cannot disinfect hinged in

struments or those with deep, narrow crevices. Chemical solutions also are unable to kill spores and Mycobacterium tuberculosis.

Chemical disinfectants provide the major means of asepticizing the patient's face and mouth. Such precaution is mandatory for subperiosteal implantations and recommended for endosseous procedures. The conventional method of asepticizing the skin is to first employ a sponge soaked in surgical green soap. This is rubbed in a circular motion, starting at the lips and working outward. When the area is thoroughly soaped, sterile water is used to wash the soap away. The area is then sponged with 70% alcohol used on a fresh sponge, followed by an application of ether on still another fresh sponge, with care being taken not to irritate the eyes. Another fresh sponge soaked in either nitromersol tincture, thimerosal, or benzalkonium chloride is then used to cleanse the area. This solution should be on the skin for at least 10 minutes prior to surgery in order to be effective.

Naturally for intraoral surgery the mouth can-not be sterilized, but it can be thoroughly cleansed with a good detergent irrigation. This is very easily done with a spray, a gauze swab, or both. The surgical area should then be painted with an antiseptic agent and allowed to dry.

Recommended sterilization procedures

Linkow recommends these techniques, which are popular and widely used by other operators. First, all instruments—except disposable scalpels and needles—are thoroughly scrubbed with soap and water. Then they are placed in an autoclave at 255° F. for 20 minutes. The implants and drilling instruments are then immersed in the bead sterilizer for 30 seconds or so. Just before they are used in the mouth, the drills and implants are placed in a cold sterilizing solution and left there until needed.

The patient and the operative site are draped. Although the operation is an oral surgical procedure, the object is not only to isolate the surgical area but also to prevent contamination from other parts of the body. The skin and mouth are then asepticized by the methods previously described.

ANESTHESIA

Most types of work that must be done on remaining teeth and on the alveolar bone before an implantation will require an anesthetic, and of course the implant site or sites must be desensitized before an intervention begins.