Table 1: Characteristics of excluded studies (reasons for exclusion).

Excluded studiesReasons for exclusion

Haugen and Johansen [25](1) Single case report, (2) unreported baseline data, (3) unreported method assessing DH/RS, and
(4) SEM study
Sim and Han [26]Unreported baseline data; abstract only
Matthews and McCulloch [27]Included participants under 18 years old
Kontturi-Närhi [10]Not all participants in clinical test study were reported having periodontal treatment
Kiyonobu et al. [28]Unreported baseline data; abstract only
Chabanski [11]Unreported baseline data
Zetterström [29]Unreported baseline data; unreported method assessing DH/RS
Kontturi-Närhi and Närhi [30]Unreported baseline data; abstract only
Tamminen et al. [31]Abstract only
Gillam et al. [32]Unreported baseline data
Heard et al. [33]Unreported baseline data
Gillam et al. [23]Unreported baseline data
Clayton et al. [34]Unreported baseline data
Fardal et al. [35]Unreported method assessing DH/RS
von Troil et al. [8]Systematic review
Wolff et al. [36]Abstract only
Froum et al. [37]Unreported baseline data
Tonetti et al. [14]Unreported baseline data
Al-Hamdan [38]Unreported baseline data