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Which surgery works best to expose impacted canines in children?

A new study settles a long-standing debate: Should dentists use an open or closed technique when children have canine teeth that fail to erupt in the upper jaw?

Lucete Fernandes Færøvig at the University of Oslo is the first author of the new, extensive study.
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Presented by: University of Oslo
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In approximately two to three per cent of children, the upper canine teeth do not erupt as they should. 

They remain trapped in the jawbone, usually on the side near the rood of the mouth. This can damage the roots of neighbouring teeth and needs to be treated with a combination of surgery and orthodontics, like braces.

“This is not just an orthodontic issue. It’s a serious medical condition,” says Lucete Fernandes Færøvig.

She is an orthodontic specialist and researcher at the University of Oslo's Faculty of Dentistry.

“The treatment begins with surgical exposure of the impacted tooth, followed by orthodontics to guide the tooth into the proper position in the dental arch,” she explains. 

But there are two common methods – open and closed surgical technique – and until now, there has been a lack of clear evidence on which method yields the best outcomes. 

Several aspects of the entire treatment are under investigation. The new study focuses solely on the first part of the treatment: the surgical exposure.

The study

To determine which method produced better outcomes, Færøvig and a research team from Norway and Sweden conducted a randomised controlled clinical trial – the most reliable form of medical research.

“This type of study sits at the top of the evidence pyramid. We compare two randomised groups under strictly controlled conditions to ensure the differences are due to the treatment itself, not random chance,” she explains.

100 children aged 10 to 16 were included in the study and randomly assigned to either the open or closed technique. 

  • Open technique: The surgeon removes gum and bone, allowing the tooth to erupt naturally. Orthodontic treatment begins once the tooth emerges from the jaw.
  • Closed technique: The tooth is exposed, and a small chain is attached to the tooth before the gum is sutured back into place. Tooth movement begins earlier, often within two weeks, using braces.

After surgery, they completed questionnaires about pain, discomfort, and use of pain medication. The surgeons also measured procedure time and recorded any complications.

The open technique caused more pain and discomfort

“It was clear that patients who underwent the open technique reported more pain, both during the procedure and in the following days. Many described the drilling and the wound area as the most uncomfortable aspects,” says Færøvig.

The first three days after surgery were the worst, and some patients had pain for more than a week.

“The open technique was quicker to perform, especially when a flap surgery was not performed. This piece of information can make a difference in busy clinics under time pressure,” she says.

On average, the procedure took several minutes less than the closed technique, which requires opening, chain attachment, and suturing.

The closed technique required more painkillers

Færøvig says it was surprising that the closed group ended up using more painkillers, though not immediately after the surgery.

“This occurred after removal of the sutures and surgical dressing," she says.

A surgical dressing is a protective material placed over a wound in the mouth after dental surgery to promote healing and protect the area from irritation and infection.

Færøvig explains that this is likely due to the chain under the gum, which can delay healing in the area over time, causing more discomfort when sutures are removed and the tissue is still tender.

“Complications were fortunately rare, but they occurred more often in the open group,” says Færøvig. “We saw more cases of bleeding and loss of surgical dressing.”

For instance, eight patients in the open group reported bleeding, while none in the closed group did. More patients also lost the dressing meant to cover the exposed area.

An answer based on research

“Previously, we had to tell patients: both methods work. Now we have a research-based answer,” says Færøvig.

They can now explain that the open surgical method is quicker but often leads to more pain, discomfort, and bleeding, while the closed method takes a bit longer but feels more comfortable. 

"This gives patients a real choice, based on knowledge, not guesswork,” she says.

Færøvig adds that both techniques still have their place and that the most important thing is personalising the treatment to each patient.

Gained international attention

The study was also recently featured on Kevin O’Brien’s Orthodontic Blog, one of the most influential voices in orthodontics globally. 

The blog, written by professor emeritus at the University of Manchester, highlights high-quality research and warns against poor or exaggerated findings.

'This was a well-conducted and ambitious randomised trial involving numerous participants, which must have required significant effort. Notably, the team reported relevant outcomes to our patients, and I would like to congratulate them on their study. I have no criticisms of their methods,' he wrote.

“It was incredibly gratifying to see the study being appraised by Kevin O’Brien. He's known for being critical and honest, so this was a vote of confidence,” says Færøvig.

The study is already published and being used in clinics. It’s an example of research that doesn’t stay locked in a drawer but directly improves patient care.

“This is research that matters. We meet patients every day who have questions. Now we have answers based on evidence,” says Færøvig.

Reference:

Færøvig et al. Closed vs open surgical exposure of palatally displaced canines: Patients’ perceptions of recovery, operating time, and complications—A 2-center randomized controlled trial, American Journal of Orthodontics & Dentofacial Orthopedics, vol. 167, 2025. DOI: 10.1016/j.ajodo.2024.11.014

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