Table 1 Main characteristics of included studies (n = 8)

Al-Wayli 2017,

Saudi Arabia [20]

50

45.5 (SD 10.8)

Clinical inspection and questionnaire

Sleep bruxism

20 units of BTX, (BOTOX; Allergan Inc.) per side

Masseter muscle bilaterally (3 points)

Traditional methods to treat bruxism

3 weeks, 2 months, 6 months, and 1 year

Pain, assessed by VAS (0 to 10 cm)

-

None of the patients reported any adverse effects

Alwayli et al. 2024, India and

Saudi Arabia [23]

40

No reported

Clinical inspection with a positive self-report

Sleep/Awake

100 units BTX-A (BOTOX; Allergan) reconstituted with 2 ml of sterile preservative-free saline. Forty units were injected

Masseter muscle bilaterally (4 points)

Placebo (saline injections)

2, 4, 8, 12, 16, 18, and 24 weeks

Pain at rest and chewing, assessed by VPS (0 to 10)

-

Not reported by the authors

Jadhao et al. 2017, India [21]

24

Not reported

Clinical inspection with a positive self-report

Sleep bruxism

Four BTX‑A (BOTOX; Allergan)

intramuscular injections for each side (30 U) within the

masseter muscles and 3 injections (20 U) within the anterior temporalis muscles, for a treatment total of

100 U

Masseter (4 points)/Temporalis (3 points)

Placebo (saline injections)/

control group

1 week, 3

months, and 6 months

Pain at rest and at chewing assessed by VAS (0 to 5)

-

Not reported by the authors

Lee et al. 2010,

Korea [22]

12

Control = 24.8 (SD 1.47)

BTX-A = 25.0 (SD 2.28)

Questionnaire

Sleep bruxism

80 MU of BTX- A

diluted in 0.8 ml of saline

Masseter (3 points)

Placebo (saline injections)

4, 8, and 12 weeks

-

Number of bruxism events per hour

assessed by EMG

/ The EMG data of

both masseter and temporalis muscles were collected

for 3 consecutive nights at home

None of the patients reported any adverse effects

Ondo et al. 2018, United States [24]

22 for pain

21 for bruxism

Placebo = 45.8 (SD 19.6)

BTX-A = 48.6 (SD 13.6)

PSG

Sleep bruxism

100 U/mL of Onabotulinum toxin-A. Sixty units were

injected bilaterally into the masseter muscles and 40 units into the bilateral temporalis

Masseter muscles (2 points)/Temporalis (3 points)

Placebo

4 to 8 weeks

Pain assessed by VAS

(0–10 cm)

Number of bruxism events per hour

assessed by PSG/EMG/

signals from the temporalis

and masseter

The injections were well tolerated. Adverse events

were limited to 2 participants with

a cosmetic change in their smile. No participant reported

dysphagia, masseter weakness, or dry mouth

Shehri et al. 2022, Syria [25]

20

29.81 (SD 7.12)

Clinical inspection and questionnaire

Sleep

100 MU of BTX-A diluted in 2 ml of

saline solution. Patients were injected with 10 MU of BTX-A per side

Masseter muscle bilaterally (2 points)

Sham therapy (stinger pen used in the blood glucose meter)

2 weeks, 3 and 4 months

Perceived pain assessed by VAS

(0–10 cm)

Muscular activity recorded by EMG in right and left masseter

muscles

Four patients had pain in the injection points in the first week of injection, and two patients had discomfort at the injection site. No side effects were reported by the rest of the included patients

Shim et al. 2020, Korea [26]

23

Placebo = 28,90 (SD 8,13)

BTX = 32.46 (SD 9.94)

Clinical inspection with a positive self-report, accordingly American Academy of Sleep Medicine

Sleep Bruxism

BTX (NABOTA, prabotulinumtoxin A)

supplied as a freeze‐dried powder of 100 U and reconstituted with 2 mL of sterile normal saline

to a concentration of 5 U/0.1 mL. A dose of 25 U was injected into each masseter muscle

Masseter muscle bilaterally (2 points)

Placebo (saline injections)

before, at 4 weeks after, and at 12 weeks after injection

-

Number of RMMA episodes per hour of sleep assessed by EMG/ submental and bilateral tibialis anterior muscles, as well as from the bilateral masseter muscles

Not reported by the authors

Yurttutan et al. 2019, Turkey [27]

73

Group A = 31 (SD 7.33)

Group B = 30.5 (SD 9.95)

Group C = 30.2 (SD 8.63)

Unclear

100-U of freeze-dried BTX-A (BOTOX; Allergan) with 1.0 mL of sodium chloride,

for a dose of 1.0 U/0.1 mL. Each participant received 90 U of BTX-A:

15 U into each temporalis muscle and 30 U into each

masseter muscle

Masseter (5 points)/ Temporalis (3 points)

Occlusal splint

occlusal splint and BTX-A

injections

7 days, 3 months, and 6 months

Pain at palpation of the

chewing muscles, assessed

by VAS (0–10)

-

None of the patients reported any adverse effects