| Popis: |
The effect o f rotary instruments and the air abrasive device on the pulp and sup porting structures of the teeth has been extensively investigated;1'6 but reports on changes in the dental pulp and, par ticularly, in the periodontal membrane, alveolar bone and temporomandibular joint after the use o f ultrasonic vibra tions, are few. This study investigates these structures in an attempt to shed light on the effects of the vibrations on living tissue. Reports on the use of commercial ultrasonic machines to cut tooth struc ture were made by Oman and Applebaum7 in 1952, and by Catuna8 in 1953. An account of the demonstration of an ultrasonic dental drill appeared in the British D en ta l Journal1 in 1954. In March of that year Nielsen, Richards and Wolcott9 reported the development of a dental ultrasonic machine operating at 25 kilocycles per second; and in Novem ber, Balamuth10 reported another that operated at 29 kilocycles per second. The machine described by Balamuth was made available to the dental profession that same year. |
