Commentary

This systematic review addresses the effect of different interventions used in treatment of lateral, extrusive and intrusive luxations of permanent anterior teeth. Three databases and two trial registries were searched for randomised and quasi-randomised controlled trials. Reference lists were cross-checked for additional articles. Two review authors independently assessed articles for eligibility. Disagreements were referred to a third author and ultimately resolved by discussion with three authors. Three case series constituting more than 160 treated luxated teeth were identified but eventually excluded as they didn't meet the eligibility criteria.

Dental traumatology relies more on retrospective studies, case series and reports than randomised clinical trials. A search on Medline in the period from January 2001 to April 2012 revealed that nearly 30% of published articles in the Journal of Dental Traumatology were case series and reports while randomised clinical trials constitute 2% only.1 This can be attributed to paucity of cases, absence of proper control group or the emergency nature of dental trauma.

The Cochrane review in hand is considered an ‘empty review' with no studies eligible for inclusion. Empty reviews are of limited use for clinicians and decision makers as they encompass either no conclusion or conclusions based on excluded studies.2,3 Conclusions deducted from Cochrane systematic reviews rely - in most instances - on randomised and quasi-randomised clinical trials, as they represent the top of the evidence pyramid. Subsequently, case series and reports are not included under the notion of ‘low-level evidence' although they can influence clinical practice.4 Systematic reviews of case series and reports can provide an acceptable alternative to empty reviews as antecedent trials regarding treatment effectiveness can be identified and results can be presented either quantitatively1 or qualitatively.5 Further, researchers would possess a more solid background required for designing future randomised clinical trials.1

Although no conclusion could be drawn from this systematic review regarding treatment effectiveness, it highlights some methodological points to be considered for future relevant research such as; considering participants as the primary unit of analysis, full reporting of outcomes for each injured tooth in participants with multiple injured teeth, define primary outcome measures as tooth and pulp survival, mobility, pain and function, while secondary outcome measures to be considered are cost, patient satisfaction and quality of life.