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| Title |
In Patients Undergoing Nonsurgical Root Canal Treatment, Gentlewave Irrigation Does Not Improve Clinical Success Compared with Conventional Syringe-Needle Irrigation |
| Clinical Question |
In patients undergoing nonsurgical root canal treatment (NSRCT), does GentleWave, as compared to conventional syringe-needle irrigation, improve rate of healing? |
| Clinical Bottom Line |
For patients receiving a NSRCT, the GentleWave system (GW) does not improve the rate of healing compared to conventional needle irrigation. Two observational studies that directly compared the two irrigation methods concur: Ather 2026 found no difference in healing or success at 1 year, and Hossini 2026 found similar success at 3 years. According to both studies, what better predicted success or failure of NSRCT was the preoperative size of the infection, rather than the use of the GW device. Grigsby 2020, a randomized control trial, also found no statistically significant differences in post-treatment pain. Overall, the evidence is of moderate quality with underpowered sample sizes. Future larger, adequately powered studies are needed. As such, current evidence does not support choosing GW over conventional irrigation to improve clinical success. |
| Best Evidence |
(you may view more info by clicking on the PubMed ID link) |
| PubMed ID |
Author / Year |
Patient Group |
Study type
(level of evidence) |
| #1) 42260197 | Ather / 2026 | 46 patients who underwent NSRCT using GW or conventional syringe-needle irrigation, with minimum follow-up of 1 year | Retrospective Clinical Study | | Key results | At 12-month follow-up, clinical assessments and radiographic analyses revealed no statistically significant differences in the percentages of healed cases (69% and 70%, respectively) or percentages of healed and healing cases (85% and 96%, respectively) between GW and conventional groups. The presence of pre-operative periapical radiolucency was significantly correlated with reduced success in both groups. However, no initial power analysis was performed, and post hoc analysis revealed an inadequate sample size. Thus, no strong conclusions can be drawn from this study. | | #2) 41276245 | Hossini / 2026 | 110 adult patients with teeth requiring initial NSRCT; 114 enrolled with 110 completing the 36-month follow-up | Retrospective Study | | Key results | At 3 years, minimally invasive treatment with GW and conventional treatment healed teeth at comparable rates when assessed using PA and clinical assessments — 69.4% vs 54.2% under strict criteria and 88.7% vs 81.3% under loose criteria, respectively, with no significant difference either way. GW patients reported significantly less moderate-to-severe postoperative pain (0% vs 8.3%, p<0.05). Although the sample size was determined by power analysis, the study may have been underpowered to detect a difference in healing outcomes. Therefore, the lack of a statistically significant difference in healing should be interpreted with caution. | | #3) 32553417 | Grigsby / 2020 | 36 adult patients (18 per group) with a molar or premolar requiring NSRCT therapy | Randomized Controlled Trial | | Key results | A similar proportion of patients reported postoperative pain in both groups (standard 72.2% vs GW 83.3%), with no meaningful difference in pain intensity at any time point (6, 24, 72, or 168 hours). Pain peaked at 6 hours and decreased steadily over the following week in both groups, remaining low-to-mild overall. | |
| Evidence Search |
PubMed: “GentleWave Outcome” |
Comments on
The Evidence |
Ather, 2026 appraised with CASP Cohort Study Checklist: Methodological strengths include a clearly defined question, objective exposure assessment, standardized procedures, validated outcome measures, blinded calibrated raters, complete follow-up, and a ≥12-month endpoint. Its pragmatic case mix and consistency with external evidence also support applicability to general endodontic practice. However, the retrospective design, inadequate sample size, and few failures per group increased the risk of selection bias and Type II error. Confounding was not formally adjusted, and co-interventions such as preparation size and irrigant concentrations differed between groups. CBCT outcomes were available for only 31 of 46 cases, and the study did not report effect estimates or confidence intervals. Therefore, the magnitude and clinical significance of the observed differences remain uncertain, and generalizability beyond a single referral center is limited.
Hossini, 2026 appraised with JBI Case-Control checklist: this study satisfies most JBI items: consistent case/control criteria, a clearly defined exposure, blinded and calibrated PAI outcome assessment, adequate 3-year follow-up, and appropriate statistics. It fails the items central to causal inference. Teeth were not matched, allocation depended on device availability, baseline diagnosis differed, and all GW cases were single-visit versus often two-visit conventional cases, with residual confounding not adequately controlled. With low post hoc power (0.34 strict, 0.15 loose), the comparable success rates and lower pain likely reflect selection bias and underpowering rather than a device effect.
Grigsby, 2020 appraised with CASP RCT checklist: Methodologically the strongest design in the set. Randomization was performed by an operator uninvolved in the study, and patient blinding was genuine, with the GW unit and suction run in both arms. Limitations include unavoidable operator non-blinding, self-reported outcomes, 18% loss to follow-up without intention-to-treat analysis, a significant baseline imbalance in pretreatment pain, and no reported confidence intervals. The trial was also inadequately powered, so the null result (72.2% vs 83.3%, not significant) indicates an underpowered study rather than proven equivalence. |
| Applicability |
When treating an ASA I or ASA II patient requiring a NSRCT on permanent teeth with mature apices, Gentlewave is an irrigation system that endodontists can consider adding to their treatment protocol – whether as a final-rinse adjunct after full instrumentation or an irrigation system combined with minimally-invasive instrumentation. Postoperative pain and healing from Gentlewave irrigation are both comparable to that of conventional irrigation. Since Gentlewave does carry additional costs, including initial equipment investment, single-use handpieces, and change in clinical workflow, it may have the greatest cost-effectiveness when used with limited instrumentation and one-visit cases to preserve dentin and reduce chairtime. |
| Specialty/Discipline |
(Endodontics) |
| Keywords |
GentleWave, Endodontic Adjunct Irrigation, Clinical Outcome, Endodontic Post-op Pain
|
| ID# |
3774 |
| Date of submission: |
10/22/2026 |
| E-mail |
chieny@livemail.uthscsa.edu |
| Author |
Yu Chen Chien |
| Co-author(s) |
I-Wen Lu |
| Co-author(s) e-mail |
lui1@livemail.uthscsa.edu |
| Faculty mentor/Co-author |
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| Faculty mentor/Co-author e-mail |
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Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?) |
post a rationale |
| None available | |
|
Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs) |
post a comment |
| None available | |
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