PURPOSE: Masticatory myofascial trigger points (TrP) are one of the major causes 
of nondental pain in the orofacial region. Intramuscular injections are 
considered the first-line treatment for myofascial TrPs. The objectives of this 
study were to evaluate and compare the effectiveness of local anesthesia (LA), 
botulinum toxin (BTX), and platelet-rich plasma (PRP) injections for the 
treatment of myofascial TrPs in the masseter muscle.
METHODS: In this retrospective study, the sample was composed of patients with 
myofascial TrPs in masseter muscle who were treated between 2016 and 2019. 
Patients were divided into 3 groups according to treatment methods: group I (LA 
injection), group II (BTX injection), and group III (PRP injection). Primary 
outcome variable was the average pain level at rest and while chewing, and 
pressure pain intensity (PPI), Jaw Functional Limitation Scale (JFLS) value, and 
quality-of-life (measured using Oral Health Impact Profile-14 (OHIP-14)) were 
secondary outcomes. The outcome variables were assessed at diagnosis, and 1, 3, 
and 6 months post-treatment.
RESULTS: The study consisted of 82 patients (group I, 27; group II, 26; group 
III, 29). At 1 and 3 months, improvement in all parameters was recorded in all 
groups. Groups I and II showed superior improvement in all parameters compared 
with group III at 3 months. Improvements in VAS pain, JFLS, and OHIP-14 values 
were significantly better in group II than group I at 3 months (P = .009; 
P = .004; P = .002). At 6 months, significant improvement in VAS pain, JFLS, and 
OHIP-14 (P = .008; P < .001; P < .01) values was recorded only in group II.
CONCLUSIONS: All procedures successfully improved the symptoms of TrPs in the 
masseter muscle at 1 and 3 months. However, BTX injection seemed superior at the 
3-month follow-up and remained effective up to 6 months.