0.018-inch and 0.022-inch bracket slots show no clinically relevant differences in orthodontic outcomesComparing 0.018 and 0.022 Bracket Sizes for Orthodontic Treatment

Frontiers in Medicine Published July 10, 2026 Study authors: Franz Tito Coronel-Zubiate, Heber Isac Arbildo-Vega, Fredy Hugo Cruzado-Oliva, Rubén Aguirre-Ipenza,… DOI ↗ Editorial oversight: Dr. Julia Lee, PhD · Oncology, Genomics & Drug Development

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Key Takeaway

Note that 0.018-inch and 0.022-inch bracket slots show no significant clinical differences in treatment outcomes.

This systematic review and critical appraisal evaluated 9 RCTs to compare 0.018-inch and 0.022-inch bracket slot sizes in patients treated with fixed orthodontic appliances. The primary focus was on clinical efficacy, including quality of finishing, treatment duration, and alignment speed. Secondary outcomes included biosafety, patient comfort, and quality of life.

The authors synthesized evidence showing no significant clinical differences between 0.018-inch and 0.022-inch systems regarding overall treatment duration, leveling efficiency, or final treatment quality. While the 0.018-inch system required one fewer visit to complete alignment, this difference was noted as lacking clinical relevance. Regarding patient experience, higher comfort and improved quality of life were reported with 0.022-inch low-friction systems.

Several limitations were identified, including high heterogeneity among the included studies which prevented a meta-analysis. The authors note that evidence certainty is low to very low for most outcomes. Clinical practice relevance suggests that no clinically relevant differences exist between these bracket sizes across most evaluated orthodontic metrics. Results should be interpreted with caution due to the limited certainty of the evidence.

Researchers reviewed nine clinical trials to compare two common types of bracket slot sizes, known as 0.018-inch and 0.022-inch, used in fixed orthodontic appliances. The goal was to see if one size performed better than the other regarding treatment speed, final tooth alignment quality, and patient comfort.

The study found that there were no significant clinical differences between the two sizes for overall treatment duration, leveling efficiency, or the final quality of the results. While the 0.018-inch system required one fewer visit to complete alignment, this difference was not considered clinically relevant.

However, patients using the 0.022-inch low-friction systems reported higher levels of comfort and a better quality of life during treatment. Because the evidence for many outcomes is currently rated as low to very low certainty, these findings should be viewed with caution. Talk to your orthodontist to decide which system best fits your personal comfort needs.

What this means for you:

Both 0.018 and 0.022 bracket sizes provide similar results for treatment quality and speed.

Common questions

Is there a difference in the final quality of my braces between different bracket sizes?

The study found no significant clinical differences in the final treatment quality or leveling efficiency when comparing 0.018-inch and 0.022-inch bracket slot sizes. Both systems are effective at achieving high-quality results for patients with dentofacial malocclusion.

Will one bracket size make my treatment finish faster?

The study found no significant clinical differences in overall treatment duration between the two sizes. While the 0.018-inch system required one fewer visit to complete alignment, this difference was not considered clinically relevant for most patients.

Which bracket size is more comfortable during treatment?

Patients using 0.022-inch low-friction systems reported higher levels of comfort and an improved quality of life compared to those using the other system. You should discuss your personal comfort preferences with your orthodontist.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedJul 2026

View Original Abstract ↓

Dentofacial malocclusion is a global public health concern and the third most prevalent oral condition after caries and periodontal disease. This systematic review evaluated the impact of bracket slot size (0.018 vs. 0.022-inch) on clinical efficacy (quality of finishing), tooth movement efficiency (treatment duration and alignment speed), and biosafety in patients treated with fixed orthodontic appliances. Randomized clinical trials were identified through comprehensive searches in PubMed, Cochrane Library, Scielo, Scopus, Web of Science, Embase, and Google Scholar up to January 2026. Studies comparing 0.018- and 0.022-inch slot brackets and reporting clinical effectiveness, efficiency, or biosafety outcomes were included. Risk of bias was assessed using RoB 2.0, and certainty of evidence was evaluated with the GRADE approach. Due to clinical and methodological heterogeneity among included studies, a statistically and clinically meaningful meta-analysis was not feasible, and results were synthesized narratively, incorporating a structured critical appraisal of the available evidence. Of 835 records screened, nine RCTs met the inclusion criteria. No significant clinical differences were observed between bracket slot sizes regarding overall treatment duration, leveling efficiency, or final treatment quality. Although the 0.018-inch system required one fewer visit to complete alignment, this difference lacked clinical relevance. No significant differences in biological risks were identified. Higher comfort and improved quality of life were reported with 0.022-inch low-friction systems. Evidence certainty was low to very low for most outcomes. Based on current evidence, no clinically relevant differences exist between 0.018- and 0.022-inch slot brackets across most evaluated orthodontic outcomes. The overall certainty of evidence is low, and findings should be interpreted with caution. This review provides a structured critical appraisal of the available data, which may assist clinicians in making evidence-based decisions regarding bracket selection. https://www.crd.york.ac.uk/PROSPERO/view/CRD42024509885, PROSPERO CRD42024509885.

0.018-inch and 0.022-inch bracket slots show no clinically relevant differences in orthodontic outcomesComparing 0.018 and 0.022 Bracket Sizes for Orthodontic Treatment

Common questions

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0.018-inch and 0.022-inch bracket slots show no clinically relevant differences in orthodontic outcomesComparing 0.018 and 0.022 Bracket Sizes for Orthodontic Treatment

Common questions

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