Effectiveness of complementary irrigation routines in debriding pulp tissue from root canals instrumented with a single reciprocating file

Abstract

Aim To compare histologically the debridement efficacy of four irrigation techniques in root canals instrumented with a reciprocating single file. Methodology From recently extracted premolars with vital pulp, 68 were selected and classified as having round canals (mesiodistal diameter similar to buccolingual) or oval‐shaped canals (mesiodistal diameter 2.5 times larger than buccolingual) (n = 32, each) by means of bidirectional radiographs. Four additional uninstrumented samples served as histological controls. The root canals of the specimens were accessed and then instrumented with Reciproc R25® and further assigned to one of four experimental groups according to the complementary irrigation technique: Group I, conventional syringe; Group II, passive ultrasonic irrigation; Group III, manual dynamic activation (MDA); and Group IV, EndoActivator®. Roots were then demineralized and the apical 3 mm was multi‐sliced and processed for histologic examination. The percentage of residual pulp tissue was calculated at each cross section. Kruskal–Wallis and Mann–Whitney tests were used to evaluate the effects of irrigation technique, root canal shape and level of cross section on the percentage of residual pulp tissue (P < 0.05). Results Irrigation technique and root canal shape significantly influenced the percentage of residual pulp tissue (P < 0.05) of canals instrumented with the R25 instrument. Percentage of residual pulp tissue was significantly less using ultrasonic irrigation (P < 0.05), but there was no difference between other irrigation techniques (P > 0.05). Round canals retained significantly less percentage of residual pulp tissue compared to oval‐shaped canals (P = 0.001). At 3 mm, there was less pulp tissue compared to levels 2 and 1 mm (P < 0.05). Conclusions In canals instrumented with R25 files, ultrasonic irrigation was more effective in removing pulp tissue in the apical level, especially for the debridement of oval‐shaped canals.

Influence of apical preparation size and irrigation technique on root canal debridement: a histological analysis of round and oval root canals

“…, Varela et al . ). Indeed, while the fixed pulp tissue may not retain properties similar to unaffected pulp tissue, this is presently the only reliable method to investigate root canal debridement at the histological level.…”

“…The results agree with a histological study (Varela et al . ), which concluded that ultrasonically activated irrigation resulted in significantly less RPT than syringe irrigation, sonic activation and manual dynamic agitation, when canals were prepared using a Reciproc R25 instrument (VDW GmBH, Munich, Germany). The present study is different from that study as the R25 is a variable tapered instrument, with an apical taper of .08, while the current study used a .04 constant‐tapered instrument.…”

“… Subgroup A , syringe and needle irrigation using a 31‐G needle (Ultradent Inc.) placed passively into the canal, 2 mm short of the working length, and moved in short vertical strokes of 2–3 mm amplitude, at an approximate rate of 100 strokes/min (Chow , Varela et al . ). The rate of irrigation was 2 mL min −1 , and a total of 10 mL of 3% NaOCl was used. Subgroup B , ultrasonically activated irrigation using a size 15, .02 taper ultrasonic file in a cordless ultrasonic generator (EndoUltra; Vista Dental Products, Racine, WI, USA).…”

“…, , Varela et al . ). Briefly, the cross‐sectional area of the root canal and remaining pulp tissue were measured to calculate the percentage of remaining pulp tissue and debris (RPT).…”

“…Such a limitation is more pronounced in the case of oval or ribbon‐shaped canals because the instrument designs do not match the root canal anatomy (Varela et al . ). Core‐less instruments such as the Self‐Adjusting File (SAF; ReDentNOVA, Ra'anana, Israel) and XP‐Endo Shaper (FKG Dentaire, La Chaux‐de‐Fonds, Switzerland) were introduced to compensate the above‐mentioned drawbacks of conventional instruments.…”