BACKGROUND: The objective was to provide a synthesis of the existing literature on the effectiveness of maxillary expansion in intercepting palatally displaced canines (PDCs).
METHODS: Studies that evaluated the effectiveness of maxillary expansion in subjects with PDCs in the mixed dentition period were included. The following electronic databases were searched until November 30, 2021: MEDLINE (via PubMed), Scopus, Google Scholar, Web of Science, and Cochrane library. Grey literature search and manual search were also performed. The risk of bias was assessed using the Cochrane tool for the one randomized controlled trial (RCT) and the ROBINS-I tool for the non-RCTs. The data were extracted and meta-analysis was performed using RevMan 5.4. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach was used to assess the certainty of evidence.
RESULTS: Four studies were selected from 9,586 records, which included one RCT and three non-RCTs. The former demonstrated a high risk of bias whereas the non-RCTs showed moderate risk. The meta-analysis of three non-RCTs found no significant improvement in the alpha angle of canines after rapid maxillary expansion, with a difference of -4.26 (95% CI -11.41 to 2.89; P = 0.24). The RCT showed an increase in the eruption rate of high-risk canines with rapid maxillary expansion. Slow maxillary expansion did not demonstrate any favorable change. The level of evidence ranged from low to very low.
CONCLUSIONS: There is insufficient evidence to recommend the use of maxillary expansion as a stand-alone procedure in intercepting PDCs. Additional well-conducted trials are required.

OBJECTIVE: This systematic review was aimed to find out possible predictive variables measured on panoramic radiographs to predict spontaneous eruption of palatally displaced canine (PDC) after interceptive extraction in late mixed dentition.
METHODS: Electronic database searches were performed in MEDLINE, Cochrane\'s CENTRAL, Scopus, and in other sources up to June 2020. Randomized and nonrandomized controlled trials, and pre-post prospective studies without control groups were considered for review. Study selection, data extraction, risk of bias assessment (by RoB 2.0, ROBINS-I, and NHLBI score), and the certainty of evidence evaluation (GRADE approach) were performed during reviewing process. Only qualitative analyses of included literature were done due to presence of between study heterogeneity.
RESULTS: Out of 970 retrieved records, 3 controlled trials and 3 prospective before and after studies without control fulfilled the eligibility criteria and were included in the review. Studies were assessed at low risk to high risk of bias. Overall certainty was moderate to very low. Results shows that PDCs in distal sectors, lower alpha angle, younger subjects, PDCs with less advanced developed root were significantly benefited from interceptive extraction. However, Vertical distance had insignificant roll on eruption prediction.
CONCLUSIONS: Interceptive extraction at younger age, mesial canine crown position (sectors), and mesial inclination of PDC (alpha angulation) are the most important variables predicting the spontaneous eruption of palatally displaced canine. Findings of this review can be utilized to make evidence-based decisions for managing PDCs with diverse sectors and mesial inclinations. However, well designed clinical trials are recommended to strengthen the evidence.

OBJECTIVE: To evaluate the effectiveness of different diagnostic variables measured on panoramic radiographs (PAN) to predict spontaneous eruption of palatally displaced canine (PDC) after interceptive extraction in late mixed dentition.
METHODS: Digital databases (MEDLINE, CENTRAL (Cochrane), Scopus, clinicaltrials.gov, ISRCTN registry) and hand searches were performed up to March 2020. Both randomized and non-randomized controlled trials were considered for the review. Study selection, data extraction, risk of bias assessment (RoB2.0 and ROBINS-I), and the certainty of evidence evaluation (GRADE) were performed according to Cochrane Handbook for Systematic Reviews of Interventions. The random-effects method for quantitative synthesis of dichotomous as well as continuous data was used.
RESULTS: Out of 767 retrieved records, 4 controlled trials fulfilled the eligibility criteria and were included in the review. Studies were assessed at low risk of bias except one. Overall certainty was strong to moderate. PDCs in distal sectors (RR: 1.621; 95%CI: 1.259 to 2.086; P<0.001) and alpha-angle <30° (SMD: -1.350; 95%CI: 1.924 to -0.776; P<0.001) were significantly benefited from interceptive extraction. However, Vertical distance of PDC cusp tip from occlusal plane had statistically insignificant (p: 0.855) roll on eruption prediction.
CONCLUSIONS: Interceptive extraction at a younger age, initial horizontal localization (sector position), and alpha-angle (initial mesial inclination) are the most important variables predicting the spontaneous eruption of palatally displaced canines. Findings of this review can be utilized to make evidence-based decisions for managing PDCs with diverse sectors and mesial inclinations. However, well-designed clinical trials are recommended to strengthen the evidence.

The aim of this systematic review was to assess whether interceptive treatment carried out in the mixed dentition period improves the position of Palatally Displaced Canines (PDC).
A systematic search was performed on various computerized databases. A hand search was also performed by reviewing the references within the examined studies and titles of the papers published over the last 30 years on various orthodontic journals.
This systematic review analysed eight articles, of which five were Randomized Clinical Trials (RCT) and three were prospective control studies. Qualitative assessment was done for all the eight studies. The effect of interceptive measures such as extraction of primary canine, Rapid Maxillary Expansion (RME), cervical pull headgear and Transpalatal Arch (TPA) on successful eruption of Palatally Displaced Canines was analyzed.
Interceptive treatment improves the position of PDC and reduces the chances of impaction. Significant changes in success rate depend on diagnosis at early mixed dentition stage. A combination of interceptive measures which includes extraction of primary canine, cervical pull headgear, TPA and RME aided in successful eruption. However, Randomized clinical trials with increased sample size, proper randomization comparing all the interceptive measures along with assessment of other factors such as patient satisfaction, pain experience and cost factor will yield more evidence based conclusions.

OBJECTIVE: To determine whether the successful management of palatally displaced permanent canines (PDCs) can be achieved by the interceptive extraction of primary maxillary canines.
METHODS: Digital databases (Medline, Scopus, Web of Science, and Cochrane) were searched to retrieve articles published from 1952 to April 2016. The university librarian developed search strategies for each database. Two calibrated reviewers independently reviewed potentially related titles and abstracts. Papers meeting the inclusion and exclusion criteria were read in full. The selected articles were evaluated and scored according to methodological quality criteria.
RESULTS: Four randomized clinical trials (RCTs) were included in the systematic review. Compared with two older studies, two more recent RCTs were found to have better study designs, were better conducted, and involved better reporting of the results. The included studies compared intervention groups (children with PDCs undergoing extraction of primary canines) with controls (subjects with PDCs but no primary canine extractions). In three of the four studies, the interceptive extraction of primary canines facilitated eruption of PDCs in more than 65% of cases. Overall, the intervention groups had a markedly higher incidence of successful eruption of PDCs (50%-69%) compared with the control groups (36%-42%).
CONCLUSIONS: Based on the available evidence, it is reasonable to conclude that eruption of PDCs can be facilitated by extraction of primary canines. However, further high-quality, randomized clinical trials are warranted in other population groups. It is hoped that this study will help orthodontists make evidence-based decisions about clinically managing PDCs.