The aim was to update a systematic review of pulp capping and partial pulpotomy by Olsson et al. (2006), by evaluating new evidence on formation of a hard tissue barrier after pulp capping and partial pulpotomy of experimental exposures in humans. PubMed (01-01-2005 to 01-03-2014) and CENTRAL were searched using specific keywords. Hand searches were made and the level of evidence for each included article was evaluated by the authors. The evidence of the conclusions was graded as strong, moderately strong, limited or insufficient. The initial search in PubMed yielded 215 abstracts. Hand searches of reference lists yielded no additional original scientific articles. After a selection process and interpretation, 22 articles were included and rated for level of evidence: no article was rated as high and seven as moderate. Overall the methodological quality of studies has improved since the previous systematic review was published in 2006. The conclusions are that there is limited scientific evidence that application of calcium hydroxide or mineral trioxide aggregate to an exposed pulp frequently results in formation of a hard tissue barrier, whereas adhesives or enamel matrix derivatives do not. There is insufficient scientific evidence that mineral trioxide aggregate promotes hard tissue formation more frequently than calcium hydroxide.