Evaluation of a magnetic resonance-compatible dentoalveolar tactile stimulus device

<p>Abstract</p> <p>Background</p> <p>Few methods exist to study central nervous system processes following dentoalveolar tactile stimulation using functional magnetic resonance imaging (fMRI), likely due to inherent technical difficulties. Our primary goal was to develop and perform feasibility testing of a novel device capable of delivering valid and reliable dentoalveolar stimuli at dental chair-side and during MRI. Details of a device designed to deliver dentoalveolar dynamic pressure stimuli are described. Device testing took place in three settings: a) laboratory testing to assess range of stimulus force intensities, b) dental chair-side to assess reliability, validity and discriminant ability in force-pain relationship; and c) MRI to evaluate magnetic compatibility and ability to evoke brain activation in painfree subjects similar to those described in the literature.</p> <p>Results</p> <p>A novel device capable of delivering valid and reliable dentoalveolar somatosensory stimulation was developed (ICC = 0.89, 0.78-1 [95% CI]). Psychophysical data analysis showed high discriminant ability in differentiating painfree controls from cases with chronic dentoalveolar pain related to deafferenting dental procedures (sensitivity = 100%, specificity = 86.7%, area under ROC curve = 0.99). FMRI results of dentoalveolar dynamic pressure pain in painfree subjects revealed activation of brain areas typically associated with acute pain processing including thalamus, primary/secondary somatosensory, insular and prefrontal cortex.</p> <p>Conclusions</p> <p>A novel psychophysical method to deliver dynamic dentoalveolar pressure stimulation was developed and validated, allowing non-invasive MRI-based exploration of central nervous system function in response to intraoral somatosensation.</p> <p>Background</p> <p>The organization of the trigeminal system is unique as it provides somatosensory innervation to the face, masticatory and oral structures, the majority of the intracranial contents <abbrgrp><abbr bid="B1">1</abbr></abbrgrp> and to specialized structures (tongue, nasal mucosa, auricle, tympanic membrane, cornea and part of the conjunctiva) <abbrgrp><abbr bid="B2">2</abbr></abbrgrp>. Somatic sensory information transmitted by the trigeminal nerve is crucial for normal orofacial function; however, the mechanisms of many chronic pain conditions affecting areas innervated by this sensory system are not well understood <abbrgrp><abbr bid="B3">3</abbr><abbr bid="B4">4</abbr><abbr bid="B5">5</abbr></abbrgrp>. The clinical presentation of chronic intraoral pain in the area of a tooth or in a site formally occupied by a tooth with no clinical or radiological signs of pathology, referred to as atypical odontalgia (AO) <abbrgrp><abbr bid="B6">6</abbr><abbr bid="B7">7</abbr></abbrgrp>, is one such chronic pain condition of particular interest to dentists that is difficult to diagnose and manage. Recent research suggests both peripheral and central nervous system mechanisms being involved in AO pathophysiology <abbrgrp><abbr bid="B8">8</abbr><abbr bid="B9">9</abbr><abbr bid="B10">10</abbr></abbrgrp>, but the majority of mechanism-based research of patients with AO has focused on the "peripheral aspect" <abbrgrp><abbr bid="B7">7</abbr></abbrgrp>.</p> <p>Functional magnetic resonance imaging (fMRI) is an established research technique to study the central aspects of pain <abbrgrp><abbr bid="B11">11</abbr></abbrgrp>. Of existing neuroimaging techniques, fMRI provides good spatial resolution of cortical and subcortical structures critical in the processing of nociception, acceptable temporal resolution, does not involve ionizing radiation, and can be performed using most MRI systems that already exist in research centers and the community. For these reasons, we sought to develop a protocol that allows us to use this tool to investigate the central mechanisms involved in the processes of intraoral pain arising from the dentoalveolar region. Using this device, our long-term objective is to improve our understanding of the underlying mechanisms of persistent dentoalveolar pain.</p> <p>In the past few years several studies used fMRI to investigate the human trigeminal system <abbrgrp><abbr bid="B12">12</abbr><abbr bid="B13">13</abbr></abbrgrp>, with a limited subset focusing on intraoral stimulation - specifically on the dentoalveolar processes, such as lip, tongue and teeth stimulation <abbrgrp><abbr bid="B14">14</abbr></abbrgrp> or only teeth <abbrgrp><abbr bid="B15">15</abbr><abbr bid="B16">16</abbr><abbr bid="B17">17</abbr></abbrgrp>. Some reasons for scarce literature on this topic may be the technical challenges involved in delivering facial/intraoral stimulation inside a MR scanner <abbrgrp><abbr bid="B17">17</abbr><abbr bid="B18">18</abbr></abbrgrp>: possibility of magnetic interference, detriment of image quality, subject discomfort and reduced working space between the subject's head and the radiofrequency coil. As a consequence a MR-compatible device would need to not only overcome these challenges but also be capable of delivering a controlled and reproducible stimuli <abbrgrp><abbr bid="B19">19</abbr></abbrgrp>, as reliability/reproducibility is a necessary feature of sensory testing <abbrgrp><abbr bid="B20">20</abbr></abbrgrp>.</p> <p>Existing MR-compatible methods of dentoalveolar stimulation are limited and do not adequately deliver stimuli across a range of non-painful to painful intensities and/or cannot be adjusted to reach posterior aspects of the dentoalveolar region. Therefore our goal was to develop and test the feasibility of a device able to: 1) provide reliable and valid dentoalveolar stimuli, 2) deliver such stimulation within the restricted space of an MR head coil, 3) be compatible for use within an MR environment, and 4) produce brain activation in painfree controls consistent to those observed by others using fMRI.</p

Frequency of Nonodontogenic Pain after Endodontic Therapy: A Systematic Review and Meta-Analysis

Little is known about ill-defined pain that persists following endodontic procedures, including an estimate of the problem’s magnitude. We conducted a systematic review of prospective studies that reported the frequency of non-odontogenic pain in patients who had undergone endodontic procedures

Frequency of Persistent Tooth Pain after Root Canal Therapy: A Systematic Review and Meta-Analysis

Little is known about the frequency of persistent pain after endodontic procedures, even though pain is a core patient-oriented outcome. We estimated the frequency of persistent pain, regardless of etiology, following endondontic treatment

Frequency of Persistent Tooth Pain after Root Canal Therapy: A Systematic Review and Meta-Analysis

Little is known about the frequency of persistent pain after endodontic procedures, even though pain is a core patient-oriented outcome. We estimated the frequency of persistent pain, regardless of etiology, following endondontic treatment

MOSAiC Extended Acknowledgement

For years, the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), together with the international MOSAiC partners, had been planning and developing the scientific, logistical and financial concept for the implementation of the MOSAiC expedition. The planning and organization of this endeavor was an enormous e˙ort, involving more than 80 institutions from 20 countries. The number of groups and individuals that significantly contributed to the success of the drift observatory goes far beyond the scope of usual polar expeditions

Electric toothbrush application is a reliable and valid test for differentiating temporomandibular disorders pain patients from controls

<p>Abstract</p> <p>Background</p> <p>Current methods for identifying patients with pain hypersensitivity are sufficiently complex to limit their widespread application in clinical settings. We assessed the reliability and validity of a simple multi-modal vibrotactile stimulus, applied using an electric toothbrush, to evaluate its potential as a screening tool for central sensitization.</p> <p>Methods</p> <p>Fourteen female temporomandibular disorders (TMD) subjects with myofascial pain (RDC/TMD Ia or Ib) and arthralgia (RDC/TMD IIIa) were compared to 13 pain-free controls of matched age and gender. Vibrotactile stimulus was performed with an electric toothbrush, applied with 1 pound pressure for 30 seconds in four locations: over the lateral pole of the temporomandibular joint, masseter, temporalis, and mid-ventral surface of forearm. Pain intensity (0–10) was recorded following the stimulus at 0, 15, 30, and 60 seconds. Test-retest reliability was assessed with measurements from 8 participants, taken 2–12 hours apart. Case versus control differentiation involved comparison of area under the curve (AUC). A receiver operating characteristic (ROC) curve was used to determine cutoff AUC scores for maximum sensitivity and specificity for this multi-modal vibrotactile stimulus.</p> <p>Results</p> <p>Test-retest reliability resulted in an ICC of 0.87 for all 4 pooled sites. ROC-determined AUC cutoff scores resulted in a sensitivity of 57% and specificity of 92% for all 4 pooled sites.</p> <p>Conclusion</p> <p>The electric toothbrush stimulus had excellent test-retest reliability. Validity of the scores was demonstrated with modest sensitivity and good specificity for differentiating TMD pain patients from controls, which are acceptable properties for a screening test.</p

Validity of preoperative clinical findings to identify dental pulp status : A National Dental Practice-Based Research Network Study

INTRODUCTION: Endodontic diagnostic tests are often used clinically to assess pulp status as a basis for the diagnosis and determination of whether root canal treatment (RCT) is indicated. Response to cold and pain on percussion are 2 common tests, yet their validity in identifying nonvital pulp in regular dental practice has not been reported. METHODS: We assessed the validity of cold and percussion tests to identify nonvital pulp in teeth requiring RCT in a dental practice setting performed by 46 general dentists and 16 endodontists in the National Dental Practice-Based Research Network. The influence of patient-, tooth-, and dentist-related characteristics was investigated. Observed bleeding from the pulp chamber was the clinical reference. Sensitivity (SN), specificity (SP), overall test accuracy (TA), positive (PPV) and negative (NPV) predictive values, and likelihood and diagnostic odds ratios (LR+, LR-, dORs) were calculated for each single test and the combined cold and percussion tests. RESULTS: Seven hundred eight patient teeth were included. Cold test showed high validity to identify a nonvital pulp status (SN = 89%, SP = 80%, TA = 84%, PPV = 81%, NPV = 88%, LR+ = 4.35, LR- = 0.14, dOR = 31.4), whereas pain on percussion had lower validity (SN = 72%, SP = 41%, TA = 56%, PPV = 54%, NPV = 60%, LR+ = 1.22, LR- = 0.69, dOR = 1.78). Combining the 2 tests did not increase validity, whereas preoperative pain, medication intake, patient age and sex, and dentist training level affected test validity significantly. CONCLUSIONS: In regular dental practice, the cold test exhibits higher validity to discriminate between vital and nonvital pulp than the tooth percussion test

Distinguishing pulpal from periapical pain by pain characteristics : National Dental PBRN

Objective Root canal treatment (RCT) is often initiated upon pain caused by inflammation of pulpal or periapical tissues. To explore to what extent certain clinical signs and symptoms differ between these two conditions, we compared pain of pulpal and periapical origin with regard to symptoms, clinical signs and diagnostic findings. Methods 62 dentists within the National Dental PBRN (www.NationalDentalPBRN.org) enrolled consecutive patients requiring RCT. Preoperative data were collected from patients (symptoms, pain characteristics) and dentists (examination findings) by questionnaires. Patients with average pain intensity >0 (0–10 numeric rating scale; NRS) for >1 day in the week preceding treatment were eligible. The definition for pain of pulpal origin was tooth pain with bleeding within the pulp chamber in the absence of periapical radiolucency. The definition for pain of periapical origin was tooth pain without bleeding pulp and presence of radiolucency. Pearson's chi-square test and t-test compared groups, and sensitivity and specificity were calculated. Results 370 patients met criteria; 234 (63%) exhibited pulpal pain and 136 (37%) had periapical pain. Patients with pain of pulpal origin more often reported sharp (p=0.004), dull (p=0.039), or shooting pain (p=0.026), provoked pain onset (p=0.002), pain aggravated by cold/hot food or drink (p<0.001) and prolonged response to cold (p<0.001). Patients with pain of periapical origin more often had tenderness to percussion (p<0.001) and biting pressure (p<0.001), as well as swelling (p<0.001). To identify pain of pulpal origin, prolonged response to cold had 71% sensitivity and 92% specificity. To identify pain of periapical origin, tenderness to percussion had 89% sensitivity and 38% specificity and for biting pressure, 81% sensitivity and 42% specificity. Conclusion Clinical characteristics and symptoms clearly differed between conditions. Although no single factor had adequate validity to be used as an indicator of the source of pain, several should be considered for inclusion in future diagnostic algorithms