Methods of space maintenance for premature loss of a primary molar: a review

This critical appraisal attempts to answer the question: What is the best method of space maintenance (SM) following premature loss of a primary molar in children under 12 years old?

A search to identify studies relevant to the PICO was conducted. Single case reports and studies prior to 1986 were excluded. The principles of GRADE were followed to appraise the evidence.

20 studies were identified, which evaluated 2265 space maintainers (SMs). Two studies were graded high quality, four moderate, eight low, and six very low. All studies reported on longevity outcomes and most on adverse effects.

There was no strong evidence favouring a particular SM, the following recommendations were made: (a) strong recommendations: In cases where rubber dam cannot be used clinicians should not use Glass Fibre Reinforced Composite Resin (GFRCR) SMs. (b) Weak recommendations: Crown and Loop SMs are recommended for loss of primary first molars; GFRCR SMs (placed under rubber dam) are recommended for loss of primary second molars. Bilateral SMs may have questionable efficacy and their use where there is loss of multiple molars in the same quadrant should be weighed against the risk of unwanted tooth movements, loss of a removable SM or no space maintenance at all.