In vitro effectiveness of a newly-designed ultrasonic scaler tip for furcation areas

This study was undertaken to perform an in vitro comparison of the accessibility and effectiveness of a newly-designed furcation tip for an ultrasonic system with conventional curets and ultrasonic scalers. The new furcation tip was spiral in shape with a spherical end. The study was conducted on three groups of 40 teeth, each comprising 20 maxillary and 20 mandibular molars. The furcation of each tooth was colored by black felt-tipped marker, after which the teeth were fixed into artificial jaw models. Each group was then instrumented by either the newly-designed furcation tip, a straight type ultrasonic scaler tip, or a Gracey curet. The teeth were photographed by a stereomicroscope from the dome surface of furcation, and the percentage of remaining colored area was calculated for each tooth. Replica models were also made and examined with scanning electron microscopy (SEM). The mean percentage of the remaining colored areas for each instrument was, for the maxillary molars and mandibular molars respectively, 15.1% and 16.7% with the newly-designed tip; 50.3% and 44.1% with the straight type ultrasonic scaler; and 61.1% and 39.5% with the Gracey curets. The newly-designed tip thus showed high levels of effectiveness and accessibility for furcation debridement. Although the SEM photographs showed that each instrument had affected the furcation surfaces in various degrees, the teeth instrumented by the newly-designed tip maintained relatively smoother surfaces. It was concluded that the newly-designed furcation tip was more effective than the straight type ultrasonic scaler or the Gracey curet in the debridement of furcation in vitro.