What is more painful: open or closed exposure of a palatally displaced canine? 

When we plan the exposure of a palatally displaced canine, we face two main options regarding the type of exposure to use. These are open and closed exposures. Both methods are commonly employed; however, there is limited information on which is most effective. This question was examined in this well-designed randomised controlled trial. 

The study team tested a modified open exposure technique that they have used for over 40 years (GOPEX). This involved, instead of surgical packing, applying glass ionomer cement to the canine. The glass ionomer remains on the tooth until it has spontaneously erupted above the gingiva. This certainly seems to be a better method than the one I used when I practised, where we placed a periodontal dressing over the open exposure and removed it after 10 days. Unfortunately, it tended to detach, and the tooth happily covered up again.

The well-known trial team from Gothenburg, Sweden, conducted this study. The European Journal of Orthodontics published the paper. Since it is open access, anyone can read it. 

What did they ask? 

They did this study too.

“Compare glass ionomer open exposure (GOPEX) with closed exposure (CE) in terms of patient-reported outcomes, surgical duration, and complications.” 

What did they do? 

They did a single-centre randomised controlled trial with a one-to-one allocation of two parallel groups. The PICO was:

Participants 

Children and adolescents under 18 years old with a palatally displaced canine were referred for treatment between March 2017 and April 2024. The main inclusion criteria were that they had a unilateral PDC and were planned for surgical exposure and orthodontic treatment. Importantly, the canine had to be positioned within sectors 2-5 on the panoramic radiograph. 

Intervention one. 

GOPEX. This was an open exposure in which glass ionomer cement was applied to the cusp tip of the exposed PDC. 

Intervention two. 

The paediatric dentist exposed the tooth, and then bonded an eyelet and chain with light-cured composite. They then sutured the flap back to its original position. 

Outcomes 

The study reported on several outcomes. The primary outcome was the amount of pain recorded by the patients. They also included information on the children’s fear of their procedure, as well as the duration of surgery and any complications. 

They used a pre-prepared randomisation scheme. Allocation concealment was stored securely at the clinic and was not accessible to the recruiting orthodontists. The allocation was carried out after obtaining the patients’ written consent. 

One of three experienced paediatric dentists performed the surgical procedures. 

They did a clear sample size calculation. Based on the amount of pain the patients could report. This revealed that 40 patients per group were required. They increased the target sample to 92 participants to compensate for dropouts. 

They conducted relevant multivariate and univariate statistical tests, and clearly outlined them in their paper. 

What did they find? 

They randomised 92 patients to the interventions: 43 to the GOPEX group and 40 to the closed exposure group. All of these patients completed the study.

During the first fourteen post-operative days, there were no significant differences between the groups in pain levels; however, after seven days of cooperation, pain scores were substantially higher in the GOPEX group than in the CE group. There were no differences in the percentage of pain-free patients, analgesic use, or chewing difficulty. 

Their overall conclusions were: 

“The GOPEX group had more pain in the first post-operative week, but no difference was seen in pain scores or any other outcome measures over the whole 14-day post-operative period.” 

What did I think? 

This was a very well-executed and well-presented trial and publication. They followed the CONSORT guidelines in their write-up; all aspects of a good trial were achieved. This is a high-quality research paper. 

When I reviewed their results, I found them to be clinically useful. Importantly, they found no difference between the two interventions in any of the outcomes they assessed. This provides us with valuable information we can share with our patients when they choose their preferred treatment.

However, while this information is useful, I could not find any details in this paper about the relative success rates of the two interventions. I contacted the authors to ask when this information will be available. They told me they are writing a paper on this and hope to publish it in early 2027. Once they have published this research, we will have the information needed to make clinical decisions with our patients.