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No high quality evidence exists that extraction of the deciduous cuspid in addition to upper molar distalization prevents impaction of palatally displaced canines.

Nikolaos Pandis DDS, MS, dr. med. dent .


Systematic Review Conclusion

The low quality of the available evidence does not permit to make any evidence-based conclusions of the effectiveness of interceptive treatment modalities in preventing impaction of palatally displaced canines (PDC).

Critical Summary Assessment

No conclusions could be made due to the small number of studies, heterogeneity of their design, and high risks of bias.

Evidence Quality Rating

Limited Evidence

Structured Abstract

Clinical Questions:

In children with mixed dentition, can interceptive treatment of PDC compared to no treatment prevent future impaction? When factoring total treatment time, side effects, cost, and patient's subjective experience of treatment procedures and pain, what is the optimal treatment modality?

Review Methods:

The authors searched three databases for articles published from 1966 to May 2009 in any language. They hand searched the reference lists of the retrieved articles, but did not report if they attempted to contact study authors or to search literature outside regular journals. During data abstraction and quality assessment, reviewer conflicts were resolved by discussion to reach consensus. The intraclass correlation coefficient (ICC) was used to assess interrater agreement. The authors did not conduct meta-analysis.

Main Results:

Two studies were included with study sample, before attrition, ranging from 50 to 75 participants. Both studies included boys and girls with similar age ranges (11.6 to 12.2 years). The included studies received a low score for quality of evidence. Results of qualitative or quantitative assessments were not reported.


Because of the low number of included studies, heterogeneity of the results, and poor study methodology, the evidence was too weak to make any evidence-based conclusions about either the effect of interceptive treatment on preventing impaction of PDC or about which treatment modality is most effective.

Source of Funding:



Importance and Context:

It has been suggested that interceptive treatment may prevent impaction of PDC1. As an early preventive measure, interceptive treatment is desirable because it may simplify orthodontic therapy2 and reduce risk for root resorption.3

Strengths and Weaknesses of the Systematic Review:

Generally, this systematic review was of high quality. The authors clearly stated their inclusion and exclusion criteria. They also reported their search terms, their reasons for excluding studies and provided a quality assessment of the included studies. Three independent reviewers selected studies and abstracted data. The authors searched three databases. They hand searched reference lists but did not report any attempt to explore literature outdide journal publications. The authors did not report blinding or calibrating reviewers, but did report excellent agreement ratings. The authors did not closely follow PRISMA reporting guidelines. They did not report any conflicts of interest.

Strengths and Weaknesses of the Evidence:

The quality of the selected studies was not ideal. Only two studies met the inclusion criteria which, although both claimed to be RCTs, lacked important methodological features. A high risk of bias was therefore identified. Study internal validity was negatively influenced by small sample sizes, selection bias and confounding (lack of clear selection criteria, questionable randomization), observer bias (no clear PDC definition, lack of blinding), and by ignoring clustering effects (statistical analysis bias). Although relative homogeneity in populations, interventions and end-points was evident, heterogeneity in results and follow-up as well as low internal validity did not allow the investigators to proceed with neither qualitative not quantitative analysis. Only one intervention comparison was identified: extraction of primary canines vs. extraction and use of cervical headgear, and drop-outs were 6% and 14% for the included studies, respectively. No studies were identified regarding side-effects, cost, and patients’ subjective experience of different treatment procedures and pain during treatment.

Implications for Dental Practice:

No clear recommendations for dental practice can be supported from the available evidence. Future research should consider interceptive treatment modalities and their effectiveness, patient satisfaction, pain experience, costs and side effects using well designed RCTs. 1. Ericson S, Kurol J 1988b Early treatment of palatally erupting maxillarycanines by extraction of primary canines. European Journal of Orthodontics 10: 283-295 2. Bishara S E 1992 Impacted maxillary canines: a review. American Journal of Orthodontics and DentofacialOrthopedics 101: 159-171 3. Ericson S, Kurol J 2000 Resorption of incisors after ectopic eruption of maxillary canines: a CT study. Angle Orthodontist 70: 415-423 Date of Critical Summary: Monday, May 16, 2011 These summaries, published under the auspices of the American Dental Association Center for Evidence-Based Dentistry, are prepared by practitioners trained in critical appraisal of published systematic reviews who work under the mentorship of experts. The summaries are not intended to, and do not, express, imply or summarize standards of care, but rather provide a concise reference for dentists to aid in understanding and applying evidence from the referenced systematic review in making clinically sound decisions as guided by their clinical judgment and by patient needs.For more information on the evidence quality rating provided above and additional critical summaries, please visit " "

Critical Summary Publication Date:


These summaries are not intended to, and do not, express, imply, or summarize standards of care, but rather provide a concise reference for dentists to aid in understanding and applying evidence from the referenced systematic review in making clinically sound decisions as guided by their clinical judgment and by patient needs. American Dental Association © 2019