Placebo Modulation of Orthodontic Pain

Not Applicable

Completed

• Conditions: Pain
• Interventions: Other: placebo; Device: orthodontic elastic separators

• Registration Number: NCT03689517
• Lead Sponsor: West China Hospital

Brief Summary

How placebo modulates orthodontic pain remains largely unknown. The present study aimed to investigate the placebo modulation of brain activity associated with orthodontic pain using fMRI.

Detailed Description

How placebo modulates orthodontic pain remains largely unknown. The present study aimed to investigate the placebo modulation of brain activity associated with orthodontic pain using fMRI. 23 voluneers were recruited in a longitudinal fMRI experiment. At both the baseline and the one-month follow-up, orthodontic separators were placed between right lower molars 24 hours before MRI scans. At baseline, the subjects were scanned without placebo while all subjects took placebos half an hour before the scan at follow-up. Scans include a bite/non-bite task fMRI and a followed resting state fMRI. A generalized linear model was used to identify pain-regulating network from task fMRI, and functional connectivity analysis of pain related brain regions was performed to study the possible modulation of placebo on connectivity of pain-regulating networks using resting-state fMRI.

Study Timeline

• Study Start: 2014-08-07
• Primary Completion: 2016-07-08
• Study Completion: 2016-12-07
• Status Verified: 2018-09
• Study First Submitted: 2018-09-25
• Study First Submitted QC: 2018-09-27
• Last Update Submitted: 2018-09-27
• Study First Posted: 2018-09-28
• Last Update Posted: 2018-09-28

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 23

Inclusion Criteria

• Female, 20-25 years old;
• Right handed;
• Understand the Visual Analog Scale;
• No history of serious illness, surgery, psychiatric disorders or neurological;
• No history of drug or alcohol abuse;
• No Maxillofacial diseases, agomphiasis, caries, metal filling material or crown;
• Individual normal occlusion with no orthodontic treatment history.

Exclusion Criteria

• claustrophobic or experienced obvious adverse reactions including fear, nausea, vomiting
• discomfort during the scan process or during menstruation.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
placebo arm	orthodontic elastic separators	Orthodontic pain was introduced by placement of orthodontic elastic separators to the mesial and distal sides of the right mandibular first molar. Participants took placebos (pills made by starch) that were told to be an effective analgesic
placebo arm	placebo	Orthodontic pain was introduced by placement of orthodontic elastic separators to the mesial and distal sides of the right mandibular first molar. Participants took placebos (pills made by starch) that were told to be an effective analgesic
sham arm	orthodontic elastic separators	Orthodontic pain was introduced by placement of orthodontic elastic separators to the mesial and distal sides of the right mandibular first molar. But participants do not take placebos

Primary Outcome Measures

Name	Time	Method
fMRI data change during MRI scan	Day 1	The fMRI data were collected with a Siemens 3.0T MRI system at West China Hospital. Scans include a bite/non-bite task fMRI and a followed resting state fMRI. Through MRI data we can investigate the modulation of brain activity associated with orthodontic pain using fMRI.

Secondary Outcome Measures

Name	Time	Method
The chronological changes of anxiety level	Day 1	Secondary outcomes concerning chronological changes of anxiety were assessed before and after orthodontic treatments through state-trait anxiety inventory (ST-AI). A higher score indicates higher anxiety level.