Author (year) (n=participants) | Intervention group (n=participants) | Comparator group (n=participants) | *Primary outcomes (scales) | Primary outcome results | Secondary outcomes | Secondary outcome results |

Coldwell et al 199723(n=48) | Alprazolam 0.25 mg (n=12) Alprazolam 0.5 mg (n=12) Alprazolam 0.75 mg (n=12) | Placebo (n=12) | Anxiety ( DAS, OSCQ and ISAR) | Decrease in number of anxious patients with increasing doses of alprazolam | Not reported | |

Branco, Bassualdo 201225 (n=30) | Diazepam 10 mg (n=10) Lorazepam 1 mg (n=10) | Placebo (n=10) | Anxiety ( Corah’s DAS) | Decreased anxiety compared with baseline levels but no statistical difference between groups | Not reported | |

Studer et al 201229Crossover (washout of 30 days)(n=12) | Midazolam 7.5 mg (n=12) | Clonidine 150 μg (n=12) | Not reported | Satisfaction with the treatment Blood pressure (BP) | 77% of patients (midazolam group) versus 75% (clonidine group) No statistical difference between the groups for BP | |

Silveira-Souto et al 201428Crossover (washout of 15 days)(n=30) | Erythrina mulungu 500 mg (n=30) | Placebo (n=30) | Anxiety ( Corah’s DAS) | Decreased anxiety compared with baseline levels but no statistical difference between groups | Heart rate Blood pressure Oxygen saturation | No statistical difference between the groups for outcomes |

Dantas et al 201727Crossover (washout of 15–30 days)(n=40) | Passiflora incarnata L. 260 mg (n=40) | Midazolam 15 mg (n=40) | Anxiety ( Corah’s DAS) | Decreased anxiety compared with baseline levels but no statistical difference between groups | Heart rate Blood pressure Oxygen saturation | No statistical difference between the groups for outcomes |

Pinheiro et al 201430(n=20) | Valeriana officinalis100 mg (n=10) | Placebo (n=10) | Anxiety ( DAS) | Herbal medicine was more effective than placebo | Heart rate Blood pressure | No statistical difference between the groups for outcomes |

Romano et al 201124(n=40) | Midazolam 15 mg (n=20) | Placebo (n=20) | Not reported | Heart rate | No statistical difference between the groups | |

Manani et al 197921(n=82) | Diazepam 15 mg (n=19) Trazodone 25 mg (n=20) Trazodone 50 mg (n=21) | Placebo (n=22) | Not reported | Heart rate Blood pressure | No statistical difference between the groups | |

Shivananda et al 201426Crossover (n=20) (washout: not reported) | Diazepam 5 mg (n=20) Diazepam 10 mg (n=20) | Placebo (n=20) | Not reported | Oxygen saturation | No statistical difference between the groups |

Dental Anxiety Scale (DAS): categorises participants into not anxious, slightly anxious, fairly anxious and very anxious.

Oral Surgery Confidence Questionnaire (OSCQ): contains 11 items rated from 0, not at all confident, to 9, extremely confident.

Interval Scale of Anxiety Response (ISAR): contains a 90 mm vertical line labelled with descriptors alongside intervals determined according to estimated magnitude: ‘calm, relaxed’, ‘a little nervous’, ‘tense, upset’, ‘afraid’, ‘very afraid’, ‘panicked’ and ‘terrified’.

Corah’s Dental Anxiety Scale: contains four questions with five possible answers that assess the patient’s feelings, signs and reactions related to the dental procedure, as very little anxious (up to five points), slightly anxious (6–10 points), moderately anxious (11–15 points) points and extremely anxious (16–20 points).

*The primary outcome ‘adverse effect’ is reported in tables 3 and 4.