Evaluating Penetration Depth of Treatment Fluids into Dentinal Tubules Using the GentleWave® System

This study evaluates the depth of sodium hypochlorite (NaOCl) penetration into dentinal tubules by using the GentleWave® System versus ultrasonic agitation. Forty extracted human molars were accessed and instrumented to size #15 with taper .04, cleaned to remove pulp tissue, immersed in crystal violet dye, and incubated (37°C) overnight. Samples were rinsed with distilled water for 30 minutes and randomly divided into four treatment groups with NaOCl as the treatment fluid (n=10 molars each): (1) controls (no treatment), (2) passive ultrasonic activation using PiezonMasterTM 700 (EMS) with ESI-tip, (3) active ultrasonic activation using PiezonMaster 700 with ESI-tip with maximum irrigation rate, and (4) the GentleWave System. Following the treatments, samples were rinsed with distilled water for one minute. Crowns were removed and roots were carefully split longitudinally, of which only 70% roots were free of cutting artifacts. Mesiobuccals and distobuccals from maxillary molars and mesials from mandibular molars (74 root halves) were evaluated for this study. The depth of NaOCl penetration into dentinal tubules was imaged and analyzed using Nikon® stereo-microscope and software. Statistical comparison was done with Welch’s t-test (p<0.05). Pearson correlation coefficients (r) were calculated for degree of dependence between depth of NaOCl penetration and distance from the apex. Group 4 when compared to Group 3 and Group 2 was significantly different (p<0.05) for the apical region of the root canals. No significant difference was observed between Group 2 and Group 3 (p>0.05). In summary, the GentleWave System demonstrated approximately four times greater NaOCl penetration depth in apical region than active ultrasonic system and was effective throughout the root canal system.