Post-treatment aesthetic outcomesin palatally displaced canines exposed by open versus closed surgical technique: A prospective cohort study and a survey.

A permanent upper(maxillary)caninetooth thatgrowsintotheroofofthemouth andfrequentlydoesnotappear (erupt)iscalled a palatally displaced canine (PDC). The reported prevalence of PDC in the population varies between1% and 3%. Management of the unerupted PDC can be lengthy, involving surgery to uncover the tooth and prolonged orthodontic (brace) treatment to straighten it; therefore, various procedures have been suggested to encourage a PDC to erupt without the need for surgical intervention. To assess the efficacy, safety and cost-effectiveness of any interceptive procedure to promote the eruption of a PDC compared to no treatment or other interceptive procedures in young people aged 9 to 14 years old. An information specialist searched four bibliographic databases up to 3 February 2021 and used additional search methods to identifypublished, unpublished and ongoing studies. We included randomised controlled trials (RCT) involving at least 80% of children aged between 9 and 14 years, who were diagnosed with an upper PDC and undergoing an intervention to enable the successful eruption of the unerupted PDC, which was compared with an untreated control group or another intervention. Two review authors, independently and in duplicate, examined titles, keywords, abstracts, full articles, extracted data and assessed risk of bias using the Cochrane Risk of Bias 1 tool (RoB1). The primary outcome was summarised with risk ratios (RR) and 95% confidence intervals (CI). We reported an intention-to-treat (ITT) analysis when data were available and a modified intention-to-treat (mITT) analysis if not. We also undertook several sensitivity analyses. We used summary of findings tables to present the main findings and our assessment of the certainty of the evidence. We included four studies, involving 199 randomised participants (164 analysed),108 girls and 91 boys, 82 of whom were diagnosed with unilateral PDC and 117 with bilateral PDC. The participants were aged between 8 and 13 years at recruitment. The certainty of the evidence was very low and future research may change our conclusions. One study (randomised 67 participants, 89 teeth) found that extracting the primary canine may increase the proportion of PDCs that successfully erupt into the mouth at 12 months compared with no extraction (RR 2.87, 95% CI 0.90 to 9.23; 45 participants, 45 PDCs analysed; very low-certainty evidence), but the CI included the possibility of no difference; therefore the evidence was uncertain. There was no evidence that extraction of the primary canine reduced the number of young people with a PDC referred for surgery at 12 months (RR 0.61 (95% CI0.29to1.28). Three studies (randomised 132 participants, 227 teeth) found no difference in the proportion of successfully erupted PDCs at 18 months with a double primary tooth extraction compared with extraction of a single primary canine (RR 0.68,95% CI0.35 to 1.31; 119 participants analysed, 203 PDCs; mITT;very low-certainty evidence). Two of these studies found no difference in the proportions referred for surgical exposure between the single and the double primary extraction groups data at 48 months (RR 0.31, 95% CI 0.06 to 1.45). There are some descriptive data suggesting that the more severe the displacement of the PDC towards the midline, the lower the proportion of successfully erupted PDCs with or without intervention. The evidence that extraction of the primary canine in a young person aged between 9 and 14 years diagnosed with a PDC may increase the proportion of erupted PDCs, without surgical intervention, is very uncertain. There is no evidence that double extraction of primary teeth increases the proportion of erupted PDC compared with a single primary tooth extraction at 18 months or the proportion referred for surgery by 48 months. Because we have only low to very low certainty in these findings, future research is necessary to help us know for sure the best way to deal with upper permanent teeth that are not erupting as expected.

To evaluate the costs of open and closed surgical exposure and subsequent orthodontic treatment for the correction of palatally displaced canines (PDCs). A multicentre, two-arm parallel group randomized controlled trial. One hundred twenty adolescents between 9 and 16 years of age, from three orthodontic specialist centres, were randomized to one of the two surgical exposure interventions. The randomization was conducted according to a two-arm parallel group 1:1 allocation ratio, using computerized lists with block randomization. In both the surgical techniques, whole mucoperiosteal flaps were raised, and bone covering the PDCs was removed. In the open technique, glass ionomer was built up on the PDC crown - reaching above the mucosa through a hole punched in the flap - to allow the canine to erupt autonomously. After eruption, the canine was orthodontically moved above the mucosa. In the closed technique, an eyelet was bonded onto the PDC, the flap was repositioned and the canine was orthodontically moved beyond the mucosa. The trial ended when the PDC was successfully aligned in the dental arch.Cost analysis was performed including costs for surgery, orthodontic treatment, emergency visits, and material, as well as costs for transports and time spent in connection with every appointment. Patients and caregivers could not be blinded due to obvious limitations of the clinical setting, while outcome assessors and data analysts were blinded. A cost-minimization analysis was performed since both exposure groups succeeded equally well in terms of treatment effects. The two different surgical exposures and following orthodontic treatments did not differ significantly in terms of costs. Costs are estimated in the Swedish setting, which needs to be considered if applying the results in other settings. Calculations of total cost do not include finishing, debonding, retention, and follow-up. There is no significant difference in costs between closed and open surgical exposure with following orthodontic treatments in PDCs. ClinicalTrials.gov, ID: NCT02186548.

The management of palatally displaced maxillary canines: Considerations and challenges

To evaluate which palatally displaced canines (PDCs) benefit from interceptive extraction of the deciduous canine, to assess possible side effects from the extraction, and to analyse other dental deviations in patients with PDCs. A sample of 67 patients (40 girls, mean age: 11.3 ± 1.1; 27 boys, mean age ± SD: 11.4 ± 0.9) with unilateral (45) or bilateral (22) PDCs were consecutively recruited and randomly allocated to extraction or non-extraction using block randomization. No patients dropped out after randomization or during the study. The patients were given a clinical examination and panoramic radiographs were taken at baseline and after 6 (T1) and 12 months (T2). An individual therapy plan was made for the PDCs that had not erupted at T2. Measurements were performed blindly and the outcome measures were: canine position and angulation, root development, midline shift, rotation, or movement of adjacent teeth into the extraction site, and frequency of other dental deviations. Interceptive deciduous canine extraction is beneficial if the alpha angle is between 20 and 30 degrees. A PDC located in sector 4 with an alpha angle >30 degrees should have immediate surgical exposure, while canines angulated less than 20 degrees and located in sector 2 can be observed without prior interceptive extraction. Deciduous canine extraction was more beneficial in younger patients with less advanced root development. Minor side effects, such as rotation or migration of teeth into the extraction space, were observed in 15 out of 35 patients. A majority of the patients had other dental deviations than PDC in the dentition. The results are only valid for patients with no space deficiency in the maxilla and with PDCs located in sector 2-4. No harms were detected. The alpha angle and sector position are good diagnostic predictors of when interceptive extraction is beneficial. Minor side effects are seen after the extraction and the majority of the patients had other dental deviations too. This trial was registered at http://www.fou.nu/is/sverige, registration number: 211141.

To analyse factors affecting the success rate of palatally displaced canines (PDCs) and eruption time and to find cut-off points to predict when interceptive extraction is beneficial versus unnecessary. Sixty-seven patients, 40 girls, 27 boys (10-13 years) with uni- (45) or bilateral (22) PDCs, persisting deciduous canine and no previous orthodontic treatment were randomly allocated for extraction or non-extraction using the block randomization method. There were no dropped out after the randomization or during the trial. Clinical examination and cone beam computed tomography was performed at 0, 6, and 12 months. Blinded measurements were done on baseline images. Erupted PDCs had a significantly smaller mesioangular angle, shorter distance of canine cusp tip-dental arch plane, and larger distance of canine cusp tip-midline, and the patients were younger compared to the non-erupted group. Faster eruption was noted of PDCs in the extraction group. Spontaneous eruption was achieved without prior deciduous canine extraction with cut-off points: initial canine cusp tip-midline of 11mm, canine cusp tip-dental arch plane of 2.5mm, or a mesioangular angle of 103 degrees. PDCs with a less favourable position, i.e. an initial cusp tip-midline of 6mm, a canine cusp tip-dental arch plane of 5mm, or a mesioangular angle of 116 degrees, will need surgical exposure despite interceptive extraction of the deciduous canine. The canine cusp tip-midline had the best predictive measure for assessing the outcome. Decision on where to place the cut-off points may differ from one operator to another, therefore results from several studies are needed to get average cut-off points. Deciduous canine extraction is the variable that affects the spontaneous eruption of the canine most. Canine cusp tip-midline, canine cusp tip-dental arch plane, and mesioangular angle might be useful for distinguishing when an interceptive extraction of the deciduous canine is beneficial or when exposure of the PDC should be implemented without previous interceptive treatment. This trial was registered in 'FoU i Sverige' (http://www.fou.nu/is/sverige), registration number: 40921. The protocol was not published before trial commencement.

The objective of this trial was to compare, in a 3-week follow-up, patients' perceptions of recovery, surgery time, and complications related to surgical exposure of palatally displaced canines (PDCs) with either the closed or the open techniques. This study was a 2-center, 2-arm parallel randomized clinical trial with a 1:1 allocation ratio. A total of 100 participants with PDC from 2 university clinics, aged<16 years, with unilateral or bilateral PDCs with cusp tip position in sectors II-IV, were randomly allocated to either closed-exposure or open-exposure techniques. Outcomes related to surgery and surgery/dressing removal interventions were analyzed by blinded assessors. Patients' perceptions during both interventions and the week postinterventions were evaluated using take-home questionnaires, which included 3 question types: visual analog scale (VAS) questions about pain/discomfort, binary questions about analgesic intake, and open questions about complications. Surgical duration and professional-reported complications were assessed in patient journals. Mixed models with random intercepts were used to examine the effects of treatment on VAS scores (Gaussian model) and the use of analgesics (logistic model). Linear regression was used to examine the effect of the treatment on the operation. Statistical significance was set at<0.05. A total of 92 participants were included with no baseline differences between the intervention groups. There were no significant differences in patient perceptions between the centers. The open approach showed higher VAS scores for pain (coefficient, 8.58 [95% confidence interval, 2.29-14.88]; P<0.01) and discomfort (coefficient, 9.15 [95% confidence interval, 2.33-15.98]; P<0.01) from the exposure operation onwards, with nonsignificantly higher scores for patients with bilateral than unilateral PDCs. No pain/discomfort score differences were observed between treatment groups or between patients with bilateral or unilateral PDCs at surgery/dressing removal intervention. There were no differences in analgesic intake after surgery, but there was significantly more consumption after suture/dressing removal with the closed technique. Overall, a shorter duration was observed for the open technique, particularly when no flap surgeries were performed. Few complications were detected and were more common in the open group. There was more pain and discomfort in the open group during surgery and the following week; however, no difference was observed during suture/dressing removal or the week after. There was increased analgesic intake in the closed group after suture dressing removal. Open surgical exposure required a shorter time, particularly when no flap surgery was performed. Complications were sparse and more common in the open group. ClinicalTrials.gov (NCT05067712) PROTOCOL: Published before trial commencement. University of Oslo.

Closed and open surgical techniques are two different main approaches to surgical exposure of palatally displaced canines (PDCs). Because there is insufficient evidence to support one technique over the other, there is a need for randomized controlled trials. To compare surgery time, complications and patients' perceptions between closed and open surgical techniques in PDCs. The trial was a multicentre, randomized, controlled trial with two parallel groups randomly allocated in a 1:1 ratio. Study participants were 119 consecutive patients from 3 orthodontic centres, with PDCs planned for surgical exposure, randomly allocated according to a computer-generated randomization list, using concealed allocation. Full-thickness mucoperiosteal flap was raised, and bone covering the canine was removed in both interventions. In closed exposure, an attachment with a chain was bonded to the canine and the flap was sutured back with the chain penetrating the mucosa. In open exposure, a window of tissue around the tooth was removed and glass ionomer cement placed on the canine crown, to prevent gingival overgrowth during spontaneous eruption. Patient perceptions were assessed with two questionnaires, for the evening on the day of operation and 7 days post-surgery. It was not possible to blind either patients or care providers to the interventions. The outcome assessors were blinded and were unaware of patients' intervention group. Seventy-five girls and 44 boys, mean age 13.4 years (SD 1.46) participated in the study and got either of the interventions (closed exposure, n = 60; open exposure, n = 59). Surgery time did not differ significantly between the interventions. Complications though were more severe in bilateral cases and the patients experienced more pain and impairment in the open group. There were no statistically significant differences regarding surgery time between the groups. Postoperative complications were similar between the groups in unilateral PDCs, but more common in the open group in bilateral cases. More patients in the open group experienced pain and impairment compared to the closed group. Trial registration: ClinicalTrials.gov, ID: NCT02186548 and Researchweb.org, ID: 127201.

To compare treatment time, patients' perceptions during orthodontic treatment, dental fear and side effects, between open and closed surgical exposures in patients with palatally displaced canines (PDCs). Multicentre, randomized controlled trial, with random 1:1 allocation of two parallel groups. One hundred and twenty patients from three different orthodontic centres were randomized into one of the two intervention arms, open or closed surgical exposure. Both techniques had mucoperiosteal flaps raised and bone removed above the PDCs. In open exposure, tissue was removed above the canine, and glass ionomer - reaching above soft tissue - was built on the crown. The canine was then left to erupt spontaneously, prior to orthodontic alignment. At closed exposure, a chain was bonded to the canine and orthodontic traction was applied under the mucosa until eruption. Orthodontic alignment of the canines was undertaken after eruption into the oral cavity, with fixed appliances in both groups. All participants were treated according to intention to treat (ITT). Due to the nature of this trial, only outcome assessors could be blinded to the intervention group. One hundred and seventeen patients completed the trial. All PDCs were successfully aligned. Total treatment time was equal in the two techniques, mean difference -0.1 months (95% CI -3.2 to 2.9, P = 0.93). The closed group experienced more pain and discomfort during the active orthodontic traction. Dental fear, root resorption and periodontal status did not show any clinically significant differences between the groups. Results of this randomized controlled trial (RCT) can be generalized only to a similar population aged 9-16 years, if exclusion criteria are met. The closed exposure group experienced more pain and discomfort mostly during active orthodontic traction. All other studied outcomes were similar between the two exposure groups. ClinicalTrials.gov, ID: NCT02186548 and Researchweb.org, ID: 127201.

Age as a limiting factor for panoramic imaging in patients with ectopic maxillary canines.

Periodontal health of palatally displaced canines treated with open or closed surgical technique: A multicenter, randomized controlled trial

The orthodontic alignment of palatally displaced canines (PDC) can be complex, with potential dental and soft tissue morbidity. Early diagnosis and provision of appropriate interceptive treatment has been shown to reduce the need for surgical exposure and extensive orthodontic treatment. This article reviews the current literature to gain insight into best available research evidence on all types of interceptive measures for the management of PDCs. Other perspectives of the PDC including development, aetiology and assessment are also be discussed. CPD/Clinical Relevance: Interceptive management of PDCs by extracting primary predecessors requires an assessment of the determinant prognostic factors for treatment success and to avoid the removal of primary canines where improvement in PDC is unlikely or where retention of the primary tooth may be the preferred long-term option.

In Part 2 of this article, we highlight the differences between the open and closed exposure techniques in the management of palatally displaced canines (PDCs), the mechanical principles of alignment and the management of ankylosis. CPD/Clinical Relevance: The wide positional variation in the presentation of PDCs requires a degree of clinical flexibility with different exposure techniques and treatment mechanics.

ABSTRACTObjectivesTo evaluate treatment time and patient perception of two surgical methods to expose a palatally displaced canine (PDC) into the oral cavity.Material and MethodsA total of 30 consecutive patients between 11 and 18 years, with maxillary displaced canines were recruited. After gaining informed consent from the patients and custodians, the patients were randomized into two groups by an independent person. Both groups received a chain attached to the crown of the canine: in group A (control group) the chain was placed under the mucoperiosteal flap to an incision on the alveolar crest and in group B (test group), the chain penetrated the mucoperiosteal flap inferiorly to the crown of the canine. Outcome measures where time to expose the PDC into the oral cavity and the patient's experience of pain and discomfort during the treatment.ResultsTwenty‐six patients full‐filled the trial, mean age was 12.9 years, (SD 1.6 years). The time to expose the canines for the control group was 11.9 months (SD 6.5) and for the test group 6.7 months (SD 3.2) The conventional method showed less pain on the day of surgery.ConclusionThe method used in the test group resulted in a 5‐month shorter time to expose the canine compared to the control group, and higher pain level on the day of surgery. For generalizability of the results, larger studies are needed.

An adolescent presenting with a palatally displaced canine (PDC) is a fairly common occurrence. The condition is expensive to treat as it involves surgical exposure (usually under general anaesthesia) followed by lengthy fixed orthodontic treatment at an average of two to three years. In the majority of cases alignment is successful. However if orthodontic alignment is unsuccessful and the tooth has to be surgically removed this can leave a large bony defect, which will be difficult to restore with a bridge or implant (see Figure 1). This article aims to give an overview of current principles and problems in the management of PDC.

To present a minimally invasive approach to expose palatally displaced canines (PDCs) using a surgical guide. Surgical guides for palatal canine exposure are fabricated with CAD/CAM technology. With adequate software, it is possible to match the STL files of the dental arch with the DICOM images of the maxilla. On the STL 3D model file, the operator can localize and determine the exact position of the impacted canine. In turn, this allows the identification of the ideal location of the window. A software application facilitates the design of the surgical guide, which is printed using a 3D printer. Exposure of PDCs can be achieved satisfactorily using surgical guides. The use of computer-guided surgical exposure of PDCs allows both the reduction of surgical time and surgical invasiveness, minimizing patients' postoperative discomfort. Controlled clinical trials are necessary to evaluate more fully any advantages of this minimally invasive technique.