# The Research Says: Is Warm Vertical Better Than Single Cone?

> Five RCTs and a systematic review find single-cone with bioceramic sealer matches warm vertical for healing, pain, and survival, and finishes faster.

- Author: Ryan Smith, DDS
- Published: 2026-08-18
- Category: The Research Says
- Canonical: https://ryansmithdds.com/warm-vertical-vs-single-cone-research

---

> **The verdict**
>
> For routine canals, single cone with a high-quality bioceramic sealer heals, hurts, and survives about the same as warm vertical compaction, and it does it in roughly half the chair time. Warm vertical still earns its place in complex anatomy, where its heat-driven fill genuinely fills more of the space. This is a technique choice by canal shape, not a hierarchy of skill.
>
> Evidence strength: **Moderate**: three RCTs from two research groups, one systematic review.

"Warm vertical is the gold standard. Single cone is lazy endo." I've heard some version of that sentence in nearly every residency and study club I've sat in, usually delivered with a little bit of judgment attached, as if reaching for a single cone and syringe of sealer says something about your commitment to the specialty.

I get where it comes from. Warm vertical compaction earned its reputation the hard way, against genuinely mediocre sealers and genuinely round obturation systems that couldn't fill an oval canal, let alone an isthmus. But two things have changed since that reputation was set: sealer chemistry, and the honest answer to whether the extra effort still buys you anything clinically. It's worth asking plainly: has technology caught up to the dogma?

The two techniques work on completely different physics. Warm vertical compaction is heat-driven: you soften gutta-percha and force it laterally into fins, isthmuses, and lateral canals, with the sealer acting as a thin gasket filling whatever the gutta-percha didn't reach. Single cone with a bioceramic sealer is hydraulic: the cone is essentially a plunger, and the sealer (hydrophilic, expansive, bioactive) does the real sealing work. Below, I've pulled the six studies that actually put these two approaches head-to-head.

[Video: https://www.youtube.com/watch?v=yOmP6hS_80Y]

## The question

The comparison: in adults undergoing nonsurgical root canal treatment on permanent teeth, does warm vertical compaction with a resin-based sealer produce better healing, less post-operative pain, or better long-term survival than single-cone obturation with a calcium silicate (bioceramic) sealer, and at what cost in chair time? A meaningful difference is one that would change what you reach for on a routine case: a healing-rate gap large enough to matter clinically, not a few percentage points inside a study's confidence interval.

## The mechanism

Warm vertical compaction relies on heat to soften gutta-percha, which is then compacted vertically and laterally so it flows into fins, isthmuses, and accessory canals that a rigid cone can't reach on its own. The sealer's job here is secondary: a thin film filling whatever microscopic space the gutta-percha itself didn't occupy. That's also its weak point: most resin-based sealers (AH Plus among them) shrink slightly on setting and can wash out over time if the gutta-percha fill isn't dense enough to compensate.

Single cone with a calcium silicate sealer inverts that relationship. The gutta-percha cone is essentially a plunger that hydraulically pushes the sealer into the space around it. The sealer itself is hydrophilic (it sets in the presence of moisture rather than in spite of it) expands slightly as it sets, is bioactive, and forms a chemical bond to dentin rather than just an adhesive one. In a round or gently oval canal, that hydraulic push can fill the space as completely as heat-softened gutta-percha does. In an irregular canal (a C-shape, a ribbon-shaped distal in a mandibular molar, an internal resorption defect) there's more empty space for a plunger to leave behind, and that's where heat's ability to actively flow into fins starts to matter again.

## What the evidence says

### Jaha, 2024: systematic review of hydraulic vs thermogenic obturation

**What they did:** Searched eight databases through February 2024 for studies comparing single-cone (hydraulic) and warm vertical (thermogenic) obturation; 12 studies met inclusion criteria out of 2,300 identified.

**What they found:** Both techniques produced satisfactory root fillings overall. Single cone was "a simple and efficient procedure... particularly suitable for situations with uncomplicated canal structures," while warm vertical "provides superior flexibility and sealing capability, especially in the complex root canal system" [1].

**Why it matters:** This is the closest thing to a bird's-eye view of the whole literature, and it lands exactly where the mechanism predicts: technique choice should follow canal anatomy, not a fixed hierarchy.

### Seog et al., 2025: five-year randomized controlled trial

**What they did:** Randomized 93 teeth to continuous wave of condensation with AH Plus versus single-cone sealer-based obturation with a calcium silicate sealer (Endoseal TCS); 56 teeth were evaluated at a mean 62-month recall.

**What they found:** Success under strict criteria was 75.8% for continuous wave versus 78.3% for single cone, no significant difference at five years [2].

**Why it matters:** Five years is real follow-up, long enough for the failures that show up late (missed isthmuses, slow-leaking sealers) to have declared themselves. Neither technique pulled ahead.

### Alzoubi et al., 2025: randomized controlled trial of outcome and obturation time

**What they did:** Randomized 212 teeth to single-cone sealer-based obturation with a calcium silicate sealer versus warm vertical compaction with a resin-based sealer, with 12–22 month follow-up (mean 12.9 months) by periapical radiograph and CBCT.

**What they found:** Success was comparable between groups by both measures, with no significant difference [3]. Single cone took a mean of 85.4 seconds to complete the fill; warm vertical took 159.7 seconds, nearly twice as long (P<.001).

**Why it matters:** This is the number that changes how you think about the choice. When outcomes are equivalent, obturation time stops being a footnote and becomes the deciding variable: multiplied across a full day of endo, that gap is real chair time.

### Alzoubi et al., 2024: randomized controlled trial of post-operative pain

**What they did:** The same trial team's companion study, 194 participants (211 teeth), comparing post-operative pain and analgesic use between the two techniques at 1, 3, and 7 days.

**What they found:** No statistically significant difference in pain or analgesic intake between groups at any time point [4].

**Why it matters:** One argument for warm vertical has been that its heat could irritate the periodontal ligament and drive up post-op pain. This trial doesn't support that concern either way, but it also doesn't show single cone has an advantage here, so pain isn't a reason to pick either technique.

### Zavattini et al., 2020: non-randomized clinical trial

**What they did:** 150 teeth treated with either warm vertical compaction and AH Plus, or single-cone with a calcium silicate sealer (BioRoot RCS); 104 assessed at 12 months by CBCT.

**What they found:** Success was 80% (AH Plus/warm vertical) versus 84% (BioRoot/single cone) by loose criteria, no significant difference [5].

**Why it matters:** An earlier, smaller data point pointing the same direction as the two RCTs above: worth noting the study was funded by the sealer's manufacturer, which is why it carries less weight than the independent trials.

### Chybowski et al., 2018: retrospective cohort

**What they did:** Reviewed 307 teeth treated with single-cone and EndoSequence bioceramic sealer in a private practice setting, mean follow-up 30.1 months, no comparison group.

**What they found:** Overall success rate was 90.9% [6]. Sealer extrusion occurred in nearly half the cases but had no significant effect on outcome.

**Why it matters:** No randomized comparator here, but it's a large, real-world number showing single-cone-with-bioceramic holds up outside a trial setting, in an ordinary practice's actual case mix.

## Evidence at a glance

| Study | Design | Sample | Follow-up | Finding | Weight |
|---|---|---|---|---|---|
| Jaha, 2024 [1] | Systematic review | 12 studies | Variable | SC suits simple canals; WVC suits complex anatomy | Moderate |
| Seog et al., 2025 [2] | RCT | 56 teeth | 5 years | 75.8% (WVC) vs 78.3% (SC), not significant | High |
| Alzoubi et al., 2025 [3] | RCT | 212 teeth | 12–22 months | Equivalent success; SC 85s vs WVC 160s | High |
| Alzoubi et al., 2024 [4] | RCT | 211 teeth | 7 days | No significant difference in post-op pain | High |
| Zavattini et al., 2020 [5] | Non-randomized trial | 104 teeth | 12 months | 80% (WVC) vs 84% (SC), not significant | Moderate |
| Chybowski et al., 2018 [6] | Retrospective cohort | 307 teeth | 30.1 months | 90.9% success, no comparator | Moderate |

*Mean time to complete the root filling, single cone versus warm vertical compaction. Data from [3].*

*Five-year success under strict criteria, continuous wave of condensation versus single cone with a calcium silicate sealer. Data from [2].*

## Where the evidence is thin

This isn't a large literature. Three of the six studies here come from one trial team (Alzoubi and colleagues) working from the same patient pool, and the Seog trial and the Alzoubi trials are the only two truly randomized, controlled comparisons with any meaningful follow-up. Everything else is a systematic review of mixed-quality studies, a non-randomized trial with industry funding, or a retrospective series with no comparator at all. Follow-up tops out at five years; nobody has published 10- or 15-year data comparing these two techniques head-to-head, which matters for a treatment meant to last decades. The micro-CT literature Jaha's review draws on shows warm vertical leaves fewer voids on imaging, but that finding hasn't translated into a measurable clinical difference in any RCT: a real reminder that a better-looking fill on a scan doesn't automatically mean a better-healing tooth. And every RCT here used one specific calcium silicate sealer; results may not generalize evenly across the many bioceramic sealers now on the market.

## What this means Monday morning

1. **Default to single cone with a premium bioceramic sealer for routine anatomy.** Round or gently oval canals, straightforward single- or double-canal teeth: the evidence shows no healing, pain, or survival penalty, and a real time savings.
2. **Switch to warm vertical for irregular anatomy.** C-shaped canals, ribbon-shaped distal canals in mandibular first molars, internal resorption defects, or any canal where you can feel on your working file that the cross-section isn't round.
3. **Don't chase micro-CT voids on a routine case.** Fewer voids on imaging hasn't shown up as a clinical benefit in any RCT here. Don't let a lab finding talk you into a technique your patient doesn't need.
4. **Use the time you save deliberately.** Nearly 75 seconds saved per canal on a molar with three or four canals adds up to real minutes: spend them on isolation, irrigation protocol, or simply not running behind.
5. **Retire "lazy" from the vocabulary.** Both techniques are legitimate; the choice is anatomy, not effort.

## The bottom line

Warm vertical compaction and single cone with bioceramic sealer produce equivalent healing, equivalent pain, and equivalent survival on routine canals: repeatedly, across independent research teams. Single cone does it faster. Save warm vertical's genuine advantage (better fill of irregular, fin-and-isthmus-heavy anatomy) for the canals that actually have it.

## References

1. Jaha HS. Hydraulic (Single Cone) Versus Thermogenic (Warm Vertical Compaction) Obturation Techniques: A Systematic Review. *Cureus*. 2024;16(6):e62925. [doi:10.7759/cureus.62925](https://doi.org/10.7759/cureus.62925) · [PubMed](https://pubmed.ncbi.nlm.nih.gov/38912073/)
2. Seog M, Kwon SK, Kim D, Shin SJ, Jung IY. Five-Year Outcomes of Root Canal Treatment Comparing Sealer-Based Obturation With Calcium Silicate-Based Sealer to Continuous Wave of Condensation: A Randomized Controlled Trial. *Journal of Endodontics*. 2025;51(5):538-546. [doi:10.1016/j.joen.2025.02.001](https://doi.org/10.1016/j.joen.2025.02.001) · [PubMed](https://pubmed.ncbi.nlm.nih.gov/39923930/)
3. Alzoubi F, Alajmi S, Alkandari A, Alqahtani S, Alanezi A, Setzer FC. The Outcome of Nonsurgical Root Canal Treatment Using Sealer-based Obturation versus Warm Vertical Compaction: A Randomized Controlled Trial. *Journal of Endodontics*. 2025;51(10):1351-1361. [doi:10.1016/j.joen.2025.07.003](https://doi.org/10.1016/j.joen.2025.07.003) · [PubMed](https://pubmed.ncbi.nlm.nih.gov/40653155/)
4. Alzoubi F, Alajmi S, Alkandari A, Alqahtani S, Alanezi A, Setzer FC. Post-operative pain in non-surgical root canal treatment after sealer-based obturation versus warm vertical compaction: A randomized clinical trial. *International Endodontic Journal*. 2024;57(9):1168-1179. [doi:10.1111/iej.14102](https://doi.org/10.1111/iej.14102) · [PubMed](https://pubmed.ncbi.nlm.nih.gov/38813933/)
5. Zavattini A, Knight A, Foschi F, Mannocci F. Outcome of Root Canal Treatments Using a New Calcium Silicate Root Canal Sealer: A Non-Randomized Clinical Trial. *Journal of Clinical Medicine*. 2020;9(3):782. [doi:10.3390/jcm9030782](https://doi.org/10.3390/jcm9030782) · [PubMed](https://pubmed.ncbi.nlm.nih.gov/32183124/)
6. Chybowski EA, Glickman GN, Patel Y, Fleury A, Solomon E, He J. Clinical Outcome of Non-Surgical Root Canal Treatment Using a Single-cone Technique with EndoSequence Bioceramic Sealer: A Retrospective Analysis. *Journal of Endodontics*. 2018;44(6):941-945. [doi:10.1016/j.joen.2018.02.019](https://doi.org/10.1016/j.joen.2018.02.019) · [PubMed](https://pubmed.ncbi.nlm.nih.gov/29606401/)

*This article summarises published research for clinicians. It is not a substitute for your own reading of the studies or your clinical judgment.*

The material question doesn't stop at the sealer. Once the canal is filled, [should we use posts or not](/posts-after-root-canal-research) covers what actually determines whether that tooth survives the restoration, and [how long do crowns really last](/the-research-says-how-long-do-crowns-really-last) follows the same tooth through its next decade. And if faster obturation is the kind of margin that matters to your day, run it through the [daily break-even calculator](/tools/daily-break-even) to see what a few saved minutes per molar are actually worth.