Correlation between different intrusion force magnitudes and pain intensity in a group of adolescent females (A randomized clinical trial)

Background: Pain resulting from orthodontic tooth movement is one of the annoying issues to the patient. This randomized clinical trial was conducted to determine the intensity of the pain that the patient experience upon teeth intrusion with different force magnitudes. Subjects and methods: fourteen female patients aged 15-18 years were selected randomly from the clinic of Orthodontic department of Faculty of Dentistry, Cairo University. Participants were divided into two equal groups (n=7). Group 1 where 25 grams of intrusive force were applied, Group 2 where 100 grams of intrusive force were applied. Via a paper visual analogue scale (VAS) distributed to each patient after the end of the three months of intrusion to assess their pain score. Results: For patients undergone 25 grams intrusive force, the mean VAS score was 1.8±0.4 with a median 2.0 and interquartile range (IQR):(2.0 to 2.0) vs. 4.4±0.5 with a median 4.0 and IQR:(4.0 to 5.0) for patients undergone 100 grams, indicating a statistically significant increased pain score among patients subjected to the higher intrusive force (absolute mean difference = 2.6, p <0.001). Conclusion: There is a positive correlation between force magnitude and pain. Pain intensity and its perception increases by increasing the intrusive force magnitude.