Table 2.

(A) Quality assessment of RCTs performed in accordance with the Cochrane Handbook for Systematic Reviews of Interventions (legend: + = adequate; ? = unclear; − = inadequate; US = university setting, DTD = defined trial design, SH = smoking habit, SZC = sample size calculation, DSM = defined statistical methods, C = calibration, DF = disclosure of funding, HSTI = hard/soft tissue improvement, ET = experienced therapist). (B) quality assessment of CCTs performed through ROBINS-I.

Study	Random Sequence Generation	Allocation Concealment	Blinding of Assessor	Blinding of Statistician	Incomplete Outcome Data	Other Sources of Bias
Borzangy et al. [23] 2015	?	+	+	?	+	US, DTD, SH, DSM, C
Schepke et al. [24] 2017	+	+	−	+	+	US, DTD, DSM, SZC, DF
Wittneben et al. [25] 2017	?	+	+	?	?	US, DTD, ET, DSM, HSTI, DF
Study	Bias due to Confounding	Bias in Selection of Participants into the Study	Bias in Classification of Interventions	Bias due to Deviations from Intended Interventions	Bias due to Missing Data	Bias in Measurement of Outcomes	Bias in Selection of the Reported Result
Borges et al. [21] 2014	Probably no	No	No	No	Probably no	Probably yes	No
Lops et al. [22] 2015	Moderate risk	Low risk	Low risk	Low risk	Low risk	Moderate risk	Low risk
Lops et al. [9] 2017	Probably yes	No	No	No	No	Probably no	No