Effectiveness of supplemental vibrational force in reducing pain associated with orthodontic treatment: a systematic review

Objective: The aim of this review was to systematically appraise the current evidence of utilizing vibration to reduce orthodontic pain. Method and materials: A comprehensive search was performed in ten databases. Only randomized controlled trials (RCTs) with patients receiving orthodontic treatment accompanied by vibrational force application were included. Risk of bias was assessed using the Cochrane tool. The lack of reasonable homogeneity across studies prevented the quantitative synthesis of the data. Results: Fifteen RCTs were included. Three out of four RCTs revealed lower pain levels in at least one time-point when aligners were enhanced by vibration. Three out of 11 RCTs found that vibration accompanying fixed appliances was effective in reducing orthodontic pain. All studies had different methodologic shortcomings including: performance bias due to lack of participants' blinding; inappropriate sample size calculation; nonuniform demographic characteristics of participants; high potential of retrospective documentation of pain perception; and attrition bias. Conclusion: It is difficult to answer the question of whether vibration alleviates orthodontic pain or not, especially with the multiple existing shortcomings. More precise research is needed. It is recommended to focus on comparing different vibrational variables in an attempt to find the optimal values that might contribute to pain reduction, including: vibrational frequency; magnitude; and number and duration of sessions per day. Based on the concept of stimulation-induced analgesia, it is suggested that future research highlights the number of vibration sessions/day. Keywords: orthodontics, pain, pain perception, systematic review, vibration