Effect of pulsed ultrasound toothbrush on Streptococcus mutans biofilm removal.

PURPOSE: To evaluate the effect of pulsed ultrasound toothbrush on the removal of biofilm formed by Streptococcus mutans (S. mutans). METHODS: S. mutans biofilm grown on apatite pellet was destructed with four different sonic action toothbrushes: 1) pulsed ultrasound with sonic vibration (PUV); 2) continuous ultrasound with sonic vibration (CUV); 3) sonic vibration only (SV); and 4) no ultrasound nor sonic vibration (control). After 3 minutes of noncontact brushing, the amount of water-insoluble glucan was measured, and the residual biofilm was observed by scanning electron microscopy. RESULTS: PUV group revealed the smallest amount of the residual water-insoluble glucans (32 ± 19%), followed by the CUV group (54 ± 12%) and the SV group (64 ± 13%). The PUV group showed a significantly lower amount of the residual water-insoluble glucan than the SV group, while no significant difference was found between SV and CUV. The bacterial adherence and aggregation notably decreased in the PUV group, compared to the remaining three groups. CLINICAL SIGNIFICANCE: The sonic vibration with pulsed ultrasound showed more reduction of the biofilm compared to the control and the sonic vibration with and without continuous ultrasound. Thus, pulsed ultrasound action may be beneficial for biofilm removal of interproximal regions.

Clinical experience of ureteroscopic treatment for ureteral transitional cell carcinoma using the Holmium:YAG laser.

The standard operative method for ureteral transitional cell carcinoma is nephrouterectomy with partial bladder excision of the ureteral orifice of the affected bladder. However, a conservative kidney operation and endoscopy are now being performed for low grade, low stage cases. We performed an operation using a Holmium: YAG laser, and examined its safety and efficacy. The patients were four men, and 1 woman aged from 68 to 87 (mean 78) years. There were 2 imperative cases (1 solitary kidney case, and 1 high-risk case), and 3 elective cases. The tumor size ranged from 8 to 25 (mean 14) mm. Urinary cytology was negative in all cases, and the tumors were pathologically diagnosed as grade 1 atypism on biopsy. A VersaPulse Select 80 laser generator, a 365 micro m SlimLine laser fiber, and an 8F rigid ureteroscope were used. A 6F double J catheter was indwelt for three weeks after the surgery. The pulse energy setting was 0.5-1.0 J, and the frequency was 10 Hz. The total amount of energy was 1.02-11.22 (mean 3.56) kJ, and the operation time was 20-97 (mean 50) min including the time for indwelling a ureteral stent. Neither urinary tract perforation nor ureteral stricture caused by the laser irradiation were observed. The patients have been followed by examining urine cytology once a month, and cystoscopy, retrograde pyelography, and urethroscopy once every 3 months. No recurrence has been observed as of 4-20 (mean 10) months postoperatively. Transurethral endoscopic resection using a Holmium: YAG laser is a safe and effective therapy for ureteral transitional cell carcinoma while preserving kidney and a good treatment outcome can be expected even in elective cases.