Title Open surgical exposure of palatally impacted canines may result in a decreased frequency of ankylosis compared to a closed surgical exposure
Clinical Question In patients with palatally impacted maxillary canines, does open surgical exposure lead to a decreased risk of ankylosis compared to the closed surgical exposure technique?
Clinical Bottom Line For orthodontists treating patients with palatally impacted canines, the open surgical technique has shown a decreased risk of ankylosis when compared to the closed surgical technique. However, as ankylosis does not exclusively occur in impacted canines treated with the closed exposure technique, one should understand the risk of ankylosis is still present regardless of technique and caution should be taken accordingly.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
29106474Cassina/20188 trials/433 patientsSystematic Review and Meta Analysis
Key resultsKey Results: The purpose of this study was to determine whether any difference in the clinical outcome exists in surgical exposure of impacted canines when implementing an open or closed surgical technique. An open exposure technique was shown to result in a decreased risk for ankylosis when compared to a closed exposure technique (OR = 0.15, 95% CI 0.03-0.83, P < 0.05). The NNT was 9, indicating that for every 9 impacted canines treated with a closed exposure technique, an additional ankylosis event would occur rather than if an open exposure technique had been utilized.
23452968Koutzoglou/2013118 patients (157 impacted canines) Prospective clinical study
Key resultsKey Results: The purpose of this study was to determine whether surgical technique, patient age, or grade of impaction had any association with ankylosis of the impacted canine. 118 patients were included in this study, with an age range of 11.2 – 46.1 years old at the start of treatment. Due to some spontaneous eruption, only 119 canines were treated via a surgical technique. The risk for ankylosis in the open exposure technique was 3.5% (2 of 57 canines) and 14.5% (9 of 62 canines) for the closed exposure technique. Possible causes of ankylosis were proposed, such as potential trauma of the periodontal ligament or cementum by the low-speed bur during surgery, chemical trauma from the etching gel when the attachment is bonded, the use of inappropriately high or misdirected orthodontic forces, or a longer traction time.
Evidence Search ("Impacted canine"[MeSH]) AND ("Ankylosis"[MeSH]) AND ("Open exposure"[MeSH]) AND ("Closed exposure"[MeSH])
Comments on
The Evidence
Validity: The evidence discussed here was designed to specifically look at the surgical techniques utilized in canine impactions and their respective effect on treatment outcome. The guidelines followed by the authors of the systematic review provided a thorough review of the literature available, but it should be noted that of the studies included, only the prospective study performed by Koutzoglou focused on ankylosis as a treatment outcome. All patients included were from a singular orthodontic practice treated by one clinician, which may lead to inapplicability in other settings, but overall encompass clinical situations that affect orthodontic specialists worldwide. Perspective: The PICO question that was asked was is the treatment outcome category. The question is important in orthodontics, periodontics, and oral surgery as these specialties often work in conjunction to treat impacted canines. The discussion between open versus closed exposure technique is broad and many clinical factors must be taken into consideration when determining which to employ. As ankylosis can be observed, although at a lower frequency in open exposure cases, the evidence is limited, and further research is needed to support a direct relationship between ankylosis and surgical technique if clinical guidelines are to be implemented. As always, adequate clinical planning and communication between specialists is needed to ensure a high probability of success in cases of impacted canines.
Applicability All patients included in this study presented with impacted maxillary canines but were of varying ages at the time of treatment. The majority of impacted canines included in the study were palatally displaced in the maxilla, which is of relevance to the PICO question asked. Evidence found in the study shows a decreased risk for ankylosis when an open exposure technique is utilized, and the canine is permitted to erupt into the oral cavity prior to orthodontic traction being applied. This was shown to be independent of patient age, sex, or degree of impaction, and can possibly be attributed to multiple factors involved in surgical technique and degree/direction of orthodontic force. More evidence is needed on this subject, but this study provides the clinician with valid information that can be utilized in any orthodontic patient population in order to potentially reduce the incidence of ankylosis when palatally impacted canines are surgically exposed.
Specialty (General Dentistry) (Oral Surgery) (Orthodontics) (Periodontics)
Keywords Canine impaction surgical techniques, impacted canine ankylosis, open exposure surgical technique, palatal canine impaction
ID# 3421
Date of submission 12/09/2019
E-mail steffenhagen@livemail.uthscsa.edu
Author Shelby Steffenhagen, DDS
Co-author(s) Austin Green, DDS
Co-author(s) e-mail greena1@livemail.uthscsa.edu
Faculty mentor Dr. Ravikumar Anthony, BDS, MDS, MS
Faculty mentor e-mail anthonyr@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
None available