Single-Visit vs. Multiple-Visit Root Canal: What the 2026 Survey Can—and Cannot—Tell You

Single-visit vs. multiple-visit root canal treatment: what the original 2026 U.S. endodontist survey found, what it did not measure, and when another visit may help.

By Silicon Valley Endodontics editorial team

If you need a root canal, it is reasonable to ask whether treatment will be finished in one appointment or whether you will return for another visit. The answer depends on the tooth, its diagnosis, the canal anatomy, what the clinician can accomplish safely, and how the tooth responds during treatment. A second visit is not automatically a sign that treatment is going badly, and a single visit is not automatically better.

Evidence box: the original study at a glance

Question: How do practicing United States endodontists report choosing single-visit versus multiple-visit root canal treatment, and which clinical, demographic, regional, and technology-related factors are associated with that choice?

Design: Tsai and Kim conducted an anonymous, cross-sectional, 30-item online questionnaire in Google Forms from April through June 2024. Participation was voluntary. Respondents gave consent before proceeding; the questionnaire used conditional branching, including a sequential cascade for lesion-size questions. Two board-certified endodontists reviewed the survey for content validity, and five practicing clinicians pilot-tested it.

Sample and denominator: Invitations went to 3,525 clinicians identified through an American Association of Endodontists member list and directory. There were 511 submissions. The authors excluded 49 submissions—3 incomplete, 30 with unclassifiable residency location, 15 with unclassifiable current practice location, and 1 submitted late—leaving 462 eligible respondents for analysis. The paper's approximately 14.5% response rate is 511 of 3,525 invited clinicians; it is not 462 of 3,525. This was a survey of clinicians, not a cohort of 462 patients.

Outcomes: The outcomes were respondents' answers about treatment preferences and perceptions. They were not measured healing, pain, complications, or tooth survival in patients. The study did not assign patients to one or two visits and did not follow treatment results.

Limitations: Self-report, voluntary participation, and the low response rate create possible selection and nonresponse bias; respondents may differ from nonrespondents in technology use, practice setting, or single-visit orientation. The estimates describe the 462 respondents, not all United States endodontists. The survey also did not directly compare preoperative radiolucency, CBCT use, tooth type or anatomy, the reason for retreatment, or several other disinfection technologies. Some terms, including adequacy of instrumentation, had no predefined operational definition.

Funding and conflicts: The paper reports support from an American Association of Endodontists Foundation research grant and a resident research grant from Temple University Maurice H. Kornberg School of Dentistry. The authors reported no conflicts of interest related to the study.

Patient meaning: A survey percentage cannot choose the number of visits for your tooth. Your endodontist can explain whether the canal can be predictably cleaned, dried, and sealed and whether the diagnosis and findings support completing treatment that day. Ask what the clinician found and what will happen between visits rather than using a population estimate as a promise.

What the survey found

Among the 462 respondents, 74.9% reported routinely completing treatment in one visit for necrotic teeth, and 92.4% reported doing so for irreversible pulpitis. For a general question about treatment when time permits, 56.9% said they predominantly perform single-visit treatment, 29.4% said they do so in all eligible cases, 12.6% predominantly perform multiple-visit treatment, and 1.1% always perform multiple-visit treatment.

These are reports about clinicians' usual practice and perceptions. Most respondents perceived no meaningful difference between protocols in postoperative complications (65.6%) or success rate (81.0%). Those answers do not establish that the protocols have the same complication rate or healing rate, because the researchers did not collect patient outcomes.

Why a second visit may enter the plan

The survey shows that visit planning changes with the scenario. Respondents reported multiple-visit treatment most often when the canal could not be dried (92.6%), with diffuse or facial swelling (79.9%), with an immature tooth and open apex (59.5%), or with localized swelling (57.4%). A majority reported single-visit treatment for a sinus tract (67.7%), when apical patency could not be achieved (57.1%), with an iatrogenic complication (56.9%), and in retreatment cases (55.0%). These are clinician responses to hypothetical or generalized scenarios, not treatment instructions or personal risk estimates.

The three factors respondents selected most often as influencing the number of visits were canal dryness (62%), adequate instrumentation (50%), and time availability (44%), followed by periapical diagnosis. In practical terms, another appointment may reflect what the clinician can establish during the examination and treatment—not a race to finish and not proof that treatment has failed.

Lesion-size results used a sequential cascade

For the lesion-size questions, respondents who chose multiple visits at one threshold were not asked the higher thresholds. Of the 462 respondents, 279 (60.4%) reported single-visit treatment at a lesion size of at least 5 mm, 205 (44.3%) at least 10 mm, and 175 (37.9%) at least 15 mm. The figure reports each percentage against the full analyzed sample of 462, while the question path means the groups answering later thresholds are selected subsets. These figures describe reported preferences, not healing probabilities for lesions of those sizes.

Technology associations are not treatment outcomes

Among respondents, 95 (20.6%) reported using GentleWave and 64 (13.9%) reported using lasers. Among the 95 GentleWave users, 84.2% said they were more likely to do a GentleWave case in one visit, and 64.2% said their overall single- versus multiple-visit proportion changed after adoption. The paper's regression models also found GentleWave use independently associated with single-visit completion in four infection-related scenarios, but not in every scenario; laser use was not an independent predictor.

An association in a voluntary clinician questionnaire does not show that a device caused better healing, fewer complications, or a need for fewer visits. Technology use may be entangled with region, clinician experience, case selection, and other factors. The paper explicitly calls for prospective research linking reported preferences to clinical outcomes. Equipment alone cannot guarantee a one-visit plan or a successful result.

What this research can—and cannot—tell you

It can tell us: how this group of United States endodontists reported approaching several clinical scenarios, which factors they said affect the number of appointments, and how preferences varied with age, sex, region, and technology use. It also documents the distribution of answers in the survey's lesion-size cascade.

It cannot tell us: whether one visit produces better healing, fewer complications, less pain, or greater long-term success for a particular patient. This was not a randomized treatment trial, an equivalence study, or a patient follow-up study. The 92.4%, 74.9%, 65.6%, 81.0%, and scenario percentages are survey estimates—not outcome rates—and they should not be presented as the percentage of root canals that will succeed in one appointment. They cannot establish that one visit is superior or that the two approaches are interchangeable for every tooth.

The original article also notes that available randomized evidence has low-to-moderate quality and that definitive superiority of either protocol has not been established. That background does not convert this survey into a trial. It is a reason to match the plan to the diagnosis, findings, and what can be done predictably for the individual tooth.

Questions to ask if another visit is recommended

A clear explanation can make a staged plan feel much less mysterious. Consider asking:

What are the pulpal and apical diagnoses? Ask what the examination and imaging show and how those findings affect the plan.
What specifically makes another visit advisable? Ask whether the concern is persistent moisture or bleeding, swelling, an immature apex, canal anatomy, instrumentation, or another finding.
What will happen between appointments? Ask about any medication or temporary restoration, what to avoid chewing, and which symptoms should prompt a call.
How will you decide the tooth is ready to seal? The clinician can explain what they need to see clinically before completing treatment.
What happens after the root canal? Ask about the permanent filling or crown, timing, expected recovery, and follow-up.

For a general overview, see our pages on root canal treatment, how endodontic diagnosis works, and what to expect at an endodontic first visit. Swelling or a suspected dental abscess deserves prompt dental advice; trouble breathing or swallowing requires emergency medical care.

Key takeaways

The original cross-sectional survey analyzed 462 eligible clinician respondents after 49 of 511 submissions were excluded; the reported response-rate denominator was 3,525 invitations.
Respondents reported routine single-visit completion of 92.4% for irreversible-pulpitis scenarios and 74.9% for necrotic-teeth scenarios.
Most respondents perceived no meaningful difference in complications or success, but the survey did not measure patient outcomes.
Another visit was commonly reported when the canal could not be dried or when swelling was present; the decision remains case-dependent.
No visit count or device in this survey proves better outcomes or guarantees what will happen for an individual tooth.

Your own visit plan should follow an examination of your tooth rather than a survey percentage. If you want to understand why one visit or multiple visits were recommended, contact our office for a consultation and ask the questions above.