Cortical representation of experimental periodontal pain: a functional magnetic resonance imaging study

Abstract

The aim of this study was to investigate central pain representations during loading of the periodontium induced by orthodontic and occlusal stress. Nineteen healthy male volunteers (25.7 ± 2.8 years) were tested on two consecutive days: after phenotyping (questionnaires) and determination of warmth (WPT) and heat (HPT) pain thresholds, functional magnetic resonance imaging was performed as event-related paradigm including 36 tooth clenchings of 3 s duration, alternating with rest periods varying between 20–30 s. The task was performed in absence (T1) and 24 h after placement of an elastic separator between the second bicuspid and the first molar on the right side of the lower jaw (T2). No significant changes in WPT and HPT were observed but pain ratings were significantly elevated at T2. Significantly elevated activation at T2, as compared to T1, was found in bilateral sensorimotor cortex, bilateral secondary sensory cortex, supplementary motor area, right rolandic operculum, and bilateral insula. Our data show for the first time in humans that periodontal stimulation, as tested by tooth clenching in the presence of an elastic separator, goes along with specific expressions of pain at behavioral and neuronal network levels. Findings supplement the existing neuroimaging literature on odontogenic pain.

Systematic review on effects of experimental orthodontic tooth displacement on brain activation assessed by fMRI

“…1 and Appendix 3 _Reasons_of_Exclusion). Finally, eight studies were deemed relevant and met the inclusion criteria for this SR (Ariji et al, 2018 ; Ariji et al, 2019 ; Jin et al, 2021 ; Maurer et al, 2021 ; Yang et al, 2015 ; Zhang et al, 2020, Jin et al, 2022 , Zhang et al, 2022 ).…”

“…and indicating the qualitative overall assessment as serious, primarily due to serious concerns in pre‐intervention due to confounding. On the other hand, Jin et al ( 2021 and 2022 ), Maurer et al ( 2021 ), Zhang et al ( 2021 and 2022 ) each recorded a cumulative score of 9 and presenting the moderate level of bias in their qualitative overall assessment. The analysis of the cumulative scores across the studies reveals a mean score of 9.37.…”

“…‐ #4 (Maurer et al, 2021 ) utilized t‐fMRI to examine the significant activation of brain regions 24 h after the insertion of an elastic separator between the right mandibular second bicuspid and first molar, combined with tooth clenching (painful tooth clenching). The study compared this task with the same participants who only clenched their teeth without the separator.…”

“…-#4 (Maurer et al, 2021) -#5 (Yang et al, 2015) utilized rs-fMRI to examine the changes in brain activity that occurred as a result of the placement of an elastic separator between the mesial and distal sides of the right mandibular first molar by measuring the BOLD signals. This study employed ALFF analysis in brain regions and FC analysis in the ROIs.…”

“…and indicating the qualitative overall assessment as serious, primarily due to serious concerns in pre-intervention due to confounding. On the other hand,Jin et al (2021 and,Maurer et al (2021),Zhang et al (2021 and each recorded a cumulative score of 9 and presenting the moderate level of bias in T A B L E 3 -VAS values pain/discomfort intensity/VAS Anxiety/MPQ (NWC, PRI, PRI-S, PRI-A,…”