Table 1 Reasons for exclusion (SPT studies)

In Chinese

Hu et al. [31]

In Chinese

Zhao et al. [32]

In German

Moene et al. [33]

Same cohort as one of the included studies—pilot study

Kruse et al. [34]

Lack of information on clinical data

Petersilka et al. [35]

Lack of information on clinical data

Petersilka et al. [36]

Lack of repeated interventions / retreatment

Flemmig et al. [12]

Lack of repeated interventions / retreatment 

Hagi et al. [37]

Lack of repeated interventions / retreatment

Lu et al. [16]

Lack of repeated interventions / retreatment

Lu et al. [38]

Lack of repeated interventions / retreatment

Moene et al. [10]

Lack of repeated interventions / retreatment

Simon et al. [39]

Lack of repeated interventions / retreatment

Wennstrom et al. [20]

Control group using water irrigation only

Sekino et al. [40]