Atypical Odontalgia: A Review of the Literature

Serum 3-Hydroxybutyrate is Expected to Serve as One of the Supportive Diagnostic Markers of Persistent Idiopathic Dentoalveolar Pain (PDAP)

Background

Persistent idiopathic dentoalveolar pain (PDAP), previously referred to as atypical odontalgia, is a chronic dental pain that occurs without signs of pathology. PDAP is considered a diagnosis of exclusion, and its definition is currently under refinement and remains ambiguous. The metabolite known as 3-hydroxybutyrate (3HB) has garnered significant interest as a potential indicator for both depression and chronic psychogenic pain. We investigated the characteristics of patients with PDAP and hypothesized that serum 3HB could support the diagnosis of PDAP.

Subjects and Methods

Forty-one patients with PDAP and 167 patients with odontogenic toothache were investigated regarding depression and anxiety scales in addition to the general dental evaluation. Blood tests including high-sensitivity CRP, HbA1c, and 3HB were performed for all patients. Associations between PDAP and patients' varying characteristics were investigated using hierarchical multivariate logistic regression analyses.

Results

There were more females, current smokers, patients with orofacial pain (such as temporomandibular joint pain, glossalgia, and headache), and people with elevated 3HB levels among patients with PDAP than among control participants. Multivariate logistic regression analyses predicting patients with PDAP identified the female sex (odds ratio [OR]: 4.16), current smoking (OR: 14.9), glossalgia (OR: 19.8) a high CES-D score (≥16) (OR: 5.98), and elevated serum 3HB (≥80 μmol/L) (OR: 18.4) factors significantly associated with PDAP.

Conclusion

Our results demonstrated that serum 3HB levels could be elevated in patients with PDAP compared to other types of odontogenic pain, although 3HB was not specific to PDAP. Based on our findings, five factors - female sex, current smoking, depressive tendencies, chronic orofacial pains, and high serum 3HB levels - could be useful for diagnosing PDAP.

Atypical odontalgia and trigeminal neuralgia: psychological, behavioral and psychopharmacological approach in a dental clinic – an overview of pathologies related to the challenging differential diagnosis in orofacial pain

Orofacial pain represents a challenge for dentists, especially if it does not have an odontogenic origin. Orofacial neuropathic pain may be chronic, is arduous to localize and may develop without obvious pathology. Comorbid psychiatric disorders, such as anxiety and depression, coexist and negatively affect this condition. This article presents one case of atypical odontalgia and one of trigeminal neuralgia treated with psychological and psychopharmacological tailored and adapted therapies, after conventional medications had failed. Additionally, an overview of the pathologies related to the challenging differential diagnosis in orofacial pain is given. 

A 68-year-old man complained of chronic throbbing and burning pain in a maxillary tooth, which worsened upon digital pressure. Symptoms did not abate after amitriptyline therapy; psychological intervention along with antianxiety drug were supplemented and antidepressant agent dosage were incremented. The patient reported improvement and satisfaction with the multidisciplinary approach to his pathology.

A 72-year-old man complained of chronic stabbing, intermittent, sharp, shooting and electric shock-like pain in an upper tooth, radiating and following the distribution of the trigeminal nerve. Pain did not recur after psychological intervention and a prescription of antidepressant and antianxiety agents, while carbamazepine therapy had not been sufficient to control pain. Due to concerns with comorbid psychiatric disorders, we adopted a patient-centered, tailored and balanced therapy, favorably changing clinical outcomes.

Comorbid psychiatric disorders have a negative impact on orofacial pain, and dentists should consider adopting tailored therapies, such as psychological counselling and behavioral and psychopharmacologic strategies, besides conventional treatments. They also must be familiar with the signs and symptoms of orofacial pain, obtaining a comprehensive view of the pathologies concerning the differential diagnosis. A prompt diagnosis may prevent pain chronicity, avoiding an increase in complexity and a shift to orofacial neuropathic pain and legal claims.

Pharmacological Approach to Atypical Odontalgia Patients: A Systematic Review of Case Reports

Background:

Atypical odontalgia (AO) is a poorly understood condition of orofacial pain and is often misdiagnosed. The pharmacological approach varies from case to case. This may be due to the differences in etiology, clinical symptoms, as well as comorbidities in each patient.

Objective:

This systematic review aimed at identifying and comprehending the adequate pharmacological approaches in AO management.

Methods:

In this systematic review, case reports that used pharmacological approach(es) as part of the AO management in the last 10 years (2010 to 2020) were reviewed using the PRISMA analysis guidelines. Initial screening was performed using keywords and inclusion criteria in several databases. Subsequently, further screening was carried out by checking for any duplication, followed by an assessment of the title and abstract and the entire content of the case report. All three authors were independently involved in studies selection based on the inclusion criteria, data extraction, and bias assessment.

Results:

Five hundred and ninety-five articles were identified from the initial search. The final result consisted of eleven case reports reviewed in this study. The use of antidepressants in AO management was reported in eight cases, anticonvulsants in five cases, antipsychotic in two cases, opioid analgesics in two cases, and topical analgesics in two cases.

Conclusion:

Based on this systematic review, various pharmacological agents showed adequate results as AO management. Antidepressants seemed to be the most effective ones (PROSPERO registration ID: CRD42021245918).

Is this really trigeminal neuralgia? Diagnostic re-evaluation of patients referred for neurosurgery

OBJECTIVES

Patients with facial pain are sometimes referred for neurosurgical treatment with a poorly documented diagnosis of trigeminal neuralgia. In such cases, neurosurgery will usually not be helpful. We conducted a re-evaluation of the diagnosis in patients referred for neurosurgical treatment of presumed trigeminal neuralgia. Our objective was to find out why and how often misdiagnosis occurred.

METHODS

A retrospective study was done in consecutive first-time patients referred for trigeminal neuralgia to our outpatient clinic in 2019. We used five ICHD-3-based clinical criteria to verify or exclude the diagnosis. In patients where trigeminal neuralgia was excluded, we established a diagnosis for their facial pain based upon medical history and a physical examination by a neurosurgeon - often supplemented with examination by an oral surgeon.

RESULTS

Thirty-eight patients were referred for presumed trigeminal neuralgia. Only 17 of them fulfilled the five criteria and were diagnosed with trigeminal neuralgia. In 20 of the remaining 21 patients trigeminal neuralgia could be clearly excluded, while one of the patients had a periodontitis closely mimicking trigeminal neuralgia. In 14 of the 21 patients we diagnosed temporomandibular dysfunction or dental conditions. MRI scans had detected low-grade neurovascular contacts in 13 of the 21 patients, a finding that was clearly overestimated by the referring neurologists in seven patients.

CONCLUSIONS

Overdiagnosis of trigeminal neuralgia was common in patients referred for neurosurgery, mostly due to insufficient clinical evaluation combined with an overestimation of MRI-detected NVCs. The clinical diagnosis should be critically re-evaluated before recommending neurosurgery to patients referred for presumed trigeminal neuralgia.

Effect of antidepressant treatment on plasma levels of neuroinflammation-associated molecules in patients with somatic symptom disorder with predominant pain around the orofacial region

OBJECTIVE

Burning mouth syndrome (BMS) and atypical odontalgia (AO) are examples of somatic symptom disorders with predominant pain around the orofacial region. Neuroinflammation is thought to play a role in the mechanisms, but few studies have been conducted. We aimed to better understand the role of neuroinflammation in the pathophysiology and treatment of BMS/AO.

METHODS

Plasma levels of 28 neuroinflammation-related molecules were determined in 44 controls and 48 BMS/AO patients both pretreatment and 12-week post-treatment with duloxetine.

RESULTS

Baseline plasma levels of interleukin (IL)-1β (p < .0001), IL-1 receptor antagonist (p < .001), IL-6 (p < .0001), macrophage inflammatory protein-1β (p < .0001), and platelet-derived growth factor-bb (.04) were significantly higher in patients than in controls. Plasma levels of granulocyte macrophage colony stimulating factor were significantly higher in patients than in controls (p < .001) and decreased with treatment (.009). Plasma levels of eotaxin, monocyte chemoattractant protein-1, and vascular endothelial growth factor decreased significantly with treatment (p < .001, .022, and .029, respectively).

CONCLUSIONS

Inflammatory mechanisms may be involved in the pathophysiology and/or treatment response of somatic symptom disorders with predominant pain around the orofacial region.

[Neurophysiological assessment of persistent idiopathic facial pain]

AIM

To study neurophysiological characteristics of persistent idiopathic facial pain (PIFP) in comparison to trigeminal neuralgia.

MATERIAL AND METHODS

Forty-five patients with PIFP at the age from 25 to 74 years (42 women and 3 men), 25 patients with trigeminal neuralgia at the age from 25 to 84 (15 women and 10 men) and 20 healthy volunteers were examined. Multimodal evoked potentials (EP): brainstem auditory (BAEPs), trigeminal (TEPs) and sympathetic skin responses (SSRs) evoked potentials were recorded. EEG with functional tests (hyperventilation, rhythmical photic stimulation and test with eye opening) was recorded as well.

RESULTS

The neurophysiological pattern of PIFP includes: 1) shortening of the latent period (LP) and an increase in peak amplitudes of short-latent components of the BAEPs on both sides in combination with signs of brainstem structure dysfunction (fusion of II-III or III-IV peaks, bifurcation of peaks and lengthening of inter-peaks intervals); 2) normal parameters of the TEPs; 3) an increase in the amplitude of autonomic components (sympathetic and parasympathetic without signs of predominance of the tone of this or that system), intensification of the autonomic reaction; 4) disorganization and acuity of the alpha rhythm, smoothing of zonal differences, presence of bilateral tapering alpha-, theta- or alpha-theta waves on the EEG.

CONCLUSION

Patients with PIFP have significant changes in EP and EEG connected with brainstem structure dysfunction and irritation of subcortical structures and autonomic disorders.

Pharmacotherapeutic outcomes in atypical odontalgia: determinants of pain relief

OBJECTIVES

There has been considerable research which has focused on clarifying the origin of pain in patients with atypical odontalgia (AO), also known as "idiopathic toothache", and on identifying effective treatment, but there has been limited success so far. In this study, we assessed the outcomes of treatment and attempted to identify factors that could account for pain remission in patients with AO.

PATIENTS AND METHODS

Data for 165 patients diagnosed with AO from June 2015 to August 2017 were retrospectively reviewed. The patients' sex, age, duration of pain, and psychiatric history were collected, along with information on pain intensity, depressive status, and catastrophizing scores. Responses at 4 and 16 weeks from the start of treatment were observed. The associations between potentially associated factors and outcome were investigated using Bayesian model averaging.

RESULTS

A 30% reduction in pain was reported by 38 patients (46.3%) at 4 weeks and by 54 patients (65.9%) at 16 weeks. The pain intensity decreased as the depression and catastrophizing score improved; all of the changes were statistically significant (P<0.001). Four elements, that is, patient sex, depression score at baseline, pain score at 4 weeks, and change in the catastrophizing score, explained 52.5% of the variation in final outcome between individual patients.

CONCLUSION

Our findings confirm the efficacy of tricyclic antidepressants (TCAs) as a treatment for AO and indicate that other medications, especially aripiprazole used in combination with a TCA, may be useful. A considerable number of patients, especially women, those with lower levels of depression at baseline, and those who responded to 4 weeks of treatment, achieved pain relief.

Oral health and behaviours of people living with Multiple Sclerosis in Australia

OBJECTIVES

The literature describing the oral health of people with Multiple Sclerosis (MS) is scant and the findings equivocal. The aim of this study was to describe the oral health and oral self-care behaviours of people living with MS and compare it to the Australian population.

METHODS

Participants enrolled with the Australian MS Longitudinal Study (AMSLS) were invited to participate in the survey using an online or paper-based questionnaire. Data were collected on level of disability, oral health, oral self-care and factors influencing attendance for oral health care.

RESULTS

Completed questionnaires were received for 1523 respondents. Over one-fifth (n = 320; 22%) rated their oral health as fair or poor, and more than half (n = 840; 57%) reported toothache in the last 12 months. These proportions were higher than those for the general Australian adult population (oral health prevalence ratio (PR) = 1.25 [1.12, 1.40]; toothache PR = 3.63 [3.39, 3.88]), and this is despite comparable or better self-maintenance habits and dental attendance reported by respondents. People with MS reported high rates of mouth dryness (68.4%), teeth sensitivity (64.7%), change of taste (40.5%) and orofacial pain (39.0%); fewer than 10% experienced none of these. There was a lower prevalence of self-reported need for treatment (extraction or filling) than in the Australian adult population (15.8% vs 32.9%).

CONCLUSIONS

People with MS have a greater oral health burden, demonstrated by their poorer self-reported oral health than the Australian adult population. Furthermore, they experience high rates of toothache, mouth dryness, teeth sensitivity, change of taste and orofacial pain. These findings are contrary to their self-reported good oral self-care and dental attendance habits and suggest some of the oral health impacts are due to MS rather than dental behaviours.

OnabotulinumtoxinA injections for atypical odontalgia: an open-label study on nine patients

Background

Atypical odontalgia (AO) manifests as continuous pain in the region of one or several teeth, in the absence of signs of dental pathology. Currently, there is insufficient evidence to establish treatment guidelines for AO. The aim of this study was to describe the effectiveness and safety of treatment with OnabotulinumtoxinA (OnabotA) on a series of patients with AO.

Methods

Nine patients with AO (four males and five females, aged between 31 and 77 years) received injections of OnabotA in the region of pain. The dosage used in each procedure ranged between 10 and 30 U, spread between 4 and 12 injection sites along the gums (n=9), the lips (n=3), and the hard palate (n=1). The median follow-up time was 27 months (interquartile range, IQR 20–40) and the median number of injection sessions per patient was seven (IQR 4.5–9). The assessment variables included the change in the maximal intensity of pain on a 0–10 numerical rating scale (NRS), the response latency, and the duration of the effect.

Results

All patients experienced a significant improvement, with ≥50% of reduction in the intensity of the maximal pain. The median of reduction of maximal pain after treatment was six points on the NRS (IQR 5–8.5). The response latency was 2–15 days and the duration of the effect was 2–6 months. No significant adverse reactions were registered.

Conclusion

OnabotA may be a safe and effective option for the treatment of AO.

Postdural Puncture Headache Treated With Epidural Blood Patch and Subsequent Resolution of Atypical Odontalgia: A Case Report

A 37-year-old gravida 5 para 4 with gestational hypertension underwent uneventful repeat cesarean delivery and tubal ligation under combined spinal-epidural anesthesia. On postoperative day 3, she developed a postural headache, unrelieved by caffeine, ibuprofen, and hydration. On postoperative day 8, she returned to the hospital for treatment. An epidural blood patch was administered, providing immediate and complete relief of her headache and bilateral upper and lower dental pain, which she noted arising concomitantly with her headache. We suspect bilateral traction on cranial nerve V2 and V3, secondary to intracranial hypotension after dural puncture, as the cause of her pain.

Comparison of orofacial thermal sensitivity assessed with simple devices and sophisticated equipment

BACKGROUND

Simple thermal devices providing reliable data are needed to detect somatosensory disturbances in non-specialized clinical settings. Currently, evidence is lacking about their use. Therefore, the aim was to compare the assessment of perceived thermal sensitivity/pain in healthy humans with a state-of-the-art thermotester and with simple inexpensive customized thermal aluminium devices.

METHODS

Twenty healthy volunteers participated in the study. The infraorbital region and the tip of the tongue were tested with the Medoc Pathway thermotester and simple aluminium thermal devices, with temperatures varying between 5-50°C. A numerical rating scale (NRS) from 0-50-100 was used for rating the perceived thermal sensitivity/painfulness. A control experiment was performed with 10 of the participants to test the potential impact of temporal summation of thermal stimuli with the use of temperature ramps (Medoc) compared with static temperature (simple devices).

RESULTS

In the original experiment, the scores from the thermotester stimulation were higher than the scores for stimulation with the simple thermal devices with mean NRS differences between devices of 7.2 and 10.2 for the two tested regions. In the control experiment, the mean NRS differences decreased to -0.3 and 2.2, respectively.

CONCLUSIONS

Provided that temporal summation of the thermal stimuli was avoided, there were only minor differences in perceived thermal sensitivity/painfulness between the two different assessment methods at both test sites. Therefore, the simple thermal devices can be useful for assessment of thermal sensitivity in clinical settings without access to expensive sophisticated equipment. However, more sophisticated equipment is needed for threshold measurements.

SIGNIFICANCE

This study indicates that simple thermal devices to some extent can be used in a comparable way with sophisticated thermal stimulators. Therefore, they can be useful in clinical practice, where access to further equipment is lacking.

Quantitative sensory testing (QST) in the orofacial region of healthy Chinese: influence of site, gender and age

OBJECTIVE

To establish a preliminary thermal and mechanical somatosensory profile using a standardized quantitative sensory testing (QST) to investigate site, gender and age differences in healthy Chinese.

MATERIALS AND METHODS

Twenty younger (age: 20-40 years, 10 men, 10 women) and twenty older (age: 41-61 years, 10 men, 10 women) healthy participants completed the study. Cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), mechanical detection threshold (MDT) and mechanical pain threshold (MPT) were measured at five sites: Left hand, bilaterally at the mental area, tip of tongue and the lower lip mucosa. Mixed model ANOVAs with repeated measures were used to analyze the data.

RESULTS

MDT(p < .001) and MPT (p < .05) were significantly higher on the hand compared to the mental areas. The CDT ( p = .006) was significantly higher and WDT (p < .001) was significantly lower at the tongue compared to lip mucosa and CDT (p < .001) was higher at the tongue mucosa than at the mental areas. WDT (p < .001) and HPT (p < .05) were significantly higher at the tip of the tongue and the lower lip mucosa compared to the mental areas. Significantly lower sensitivity for WDT (p < .001) and CDT (p = .004) were found in the older group compared to the younger group. Significant gender differences were found with less sensitivity for WDT (p = .024) and MDT (p = .003) in men compared to women.

CONCLUSIONS

Application of standardized QST can provide valuable information of orofacial somatosensory phenotypes in a Chinese population. Age, gender and site are mandatory to control for.

Psychiatric comorbidities in patients with Atypical Odontalgia

OBJECTIVE

Atypical Odontalgia (AO) is a condition characterized by tooth pain with no apparent cause. Although psychiatric comorbidity seems to be very common, it has rarely been studied. To clarify the influence of psychiatric comorbidity on the clinical features in patients with AO, we retrospectively evaluated their examination records.

METHODS

Clinical features and psychiatric diagnoses of 383 patients with AO were investigated by reviewing patients' medical records and referral letters. Psychiatric diagnoses were categorized according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). We also analyzed visual analogue scale (VAS), self-rating depression scale (SDS), and the short-form McGill pain questionnaire (SF-MPQ) scores.

RESULTS

Of the 383 patients with AO, 177 (46.2%) had comorbid psychiatric disorders. The most common were depressive disorders (15.4%) and anxiety disorders (10.1%). Serious psychotic disorders such as bipolar disorder (3.0%) and schizophrenia (1.8%) were rare. Dental trigger of AO was reported in 217 (56.7%) patients. There were no significant correlations between psychiatric comorbidities and most of the demographic features. Higher VAS and SDS scores, higher frequency of sleep disturbance, and higher ratings of "Fearful" and "Punishing-cruel" descriptors of the SF-MPQ were found in patients with psychiatric comorbidity.

CONCLUSIONS

About half of AO patients had comorbid psychiatric disorders. Dental procedures are not necessarily causative factors of AO. In AO patients with comorbid psychiatric disorders, pain might have a larger emotional component than a sensory one. VAS, SDS, and SF-MPQ scores might aid in the noticing of underlying comorbid psychiatric disorders in AO patients.

Evaluating Burning Mouth Syndrome as a Comorbidity of Atypical Odontalgia: The Impact on Pain Experiences

OBJECTIVE

This study aimed (1) to investigate the differences in clinical characteristics of patients between 2 groups, those who have atypical odontalgia (AO) only and those who have AO with burning mouth syndrome (BMS), and (2) to assess the influence of psychiatric comorbidity factors on patients' experiences.

METHOD

Medical records and psychiatric referral forms of patients visiting the Psychosomatic Dentistry Clinic of Tokyo Medical and Dental University between 2013 and 2016 were reviewed. The final sample included 2 groups of 355 patients: those who have AO only (n = 272) and those who have AO with BMS (AO-BMS; n = 83). Clinicodemographic variables (gender, age, comorbid psychiatric disorders, and history of headache or sleep disturbances) and pain variables (duration of illness, pain intensity, and severity of accompanying depression) were collected. Initial pain assessment was done using the Short-Form McGill Pain Questionnaire, and depressive state was determined using the Zung Self-Rating Depression Scale.

RESULTS

The average age, female ratio, and sleep disturbance prevalence in the AO-only group were significantly lower than those in AO-BMS group. AO-BMS patients rated overall pain score and present pain intensity significantly higher than did the AO-only patients (P = 0.033 and P = 0.034, respectively), emphasizing sharp (P = 0.049), hot-burning (P = 0.000), and splitting (P = 0.003) characteristics of pain. Patients having comorbid psychiatric disorders had a higher proportion of sleep disturbance in both groups and a higher proportion of depressive state in the AO-only group.

CONCLUSIONS

AO-BMS patients have different epidemiological characteristics, sleep quality, and pain experiences compared to AO-only patients. The presence of psychiatric comorbidities in both groups may exacerbate sleep quality. We suggest that BMS as a comorbid oral disorder in AO patients contributes to a more intensively painful experience.

Neuron-Glia Crosstalk and Neuropathic Pain: Involvement in the Modulation of Motor Activity in the Orofacial Region

Neuropathic orofacial pain (NOP) is a debilitating condition. Although the pathophysiology remains unclear, accumulating evidence suggests the involvement of multiple mechanisms in the development of neuropathic pain. Recently, glial cells have been shown to play a key pathogenetic role. Nerve injury leads to an immune response near the site of injury. Satellite glial cells are activated in the peripheral ganglia. Various neural and immune mediators, released at the central terminals of primary afferents, lead to the sensitization of postsynaptic neurons and the activation of glia. The activated glia, in turn, release pro-inflammatory factors, further sensitizing the neurons, and resulting in central sensitization. Recently, we observed the involvement of glia in the alteration of orofacial motor activity in NOP. Microglia and astroglia were activated in the trigeminal sensory and motor nuclei, in parallel with altered motor functions and a decreased pain threshold. A microglial blocker attenuated the reduction in pain threshold, reduced the number of activated microglia, and restored motor activity. We also found an involvement of the astroglial glutamate–glutamine shuttle in the trigeminal motor nucleus in the alteration of the jaw reflex. Neuron–glia crosstalk thus plays an important role in the development of pain and altered motor activity in NOP.

Clinical features of atypical odontalgia; three cases and literature reviews

Background

Atypical odontalgia (AO) is a disease characterized by continuous pain affecting the teeth or tooth sockets after extraction in the absence of any identifiable cause on clinical or radiographic examination. Antidepressants, such as amitriptyline, are reported to be effective in the treatment of AO; however, their efficacy varies depending on the case. In this article, we report three types of AO and discuss its heterogeneity and management.

Case presentation

In the first case, a 58-year-old woman presented with a heavy, splitting pain in the four maxillary front post-crown teeth, as if they were being pressed from the side. Her symptoms abated with 20 mg of amitriptyline. In the second case, a 39-year-old woman presented with a feeling of heaviness pain on the right side of maxillary and mandibular molar teeth, face, whole palate, and throat. She was unable to function because of her pain. Her symptoms drastically subsided with 3 mg of aripiprazole. In the third case, a 54-year-old woman presented with a tingling sensation on the left mandibular second premolar and first molar, and an uncomfortable feeling on her provisional prosthesis that made it unbearable to keep the caps on. Her symptoms diminished with 2 mg of aripiprazole added to 30 mg of mirtazapine.

Conclusions

AO shows various features and responses to drugs. It is considered not only a purely sensory problem, but also a considerably complex psychological problem, such as rumination about the pain. Investigating the difference in pharmacotherapeutic responses might help to advance the treatment of AO.

Managing the oral side-effects of medications used to treat multiple sclerosis

BACKGROUND

Many medications used to manage multiple sclerosis (MS) affect oral health. This review aimed to identify the oral side-effects of the current drugs recommended in Australia to treat MS and make dental practitioners aware of the range of symptoms.

METHODS

The Australian Therapeutic Guidelines and the Australian Medicines Handbook were searched for medications used to treat MS. For each medication, the generic name, class, route of administration, dosage and drug company reported side-effects were extracted from the online Monthly Index of Medical Specialties (MIMs) database. Meyler's Side-effect of Drugs Encyclopaedia was used to identify any additional oral adverse reactions to medications used to treat MS.

RESULTS

Fourteen drugs were identified for the treatment of MS progression and 13 drugs for the treatment of MS symptoms. For these medications, 18 oral side-effects were documented: xerostomia was the most common, followed by dysgeusia, dysphagia, mouth ulceration and sinusitis. Anticholinergic drugs caused xerostomia while immunosuppressants resulted in more infection-related side-effects.

CONCLUSIONS

Dental practitioners should be aware of the range of symptoms likely to be reported by this population. Clinicians are encouraged to continue providing dental care for their patients who develop MS and refer complex cases to specialists.

Persistent idiopathic facial pain

Background

Persistent idiopathic facial pain (PIFP) is a chronic disorder recurring daily for more than two hours per day over more than three months, in the absence of clinical neurological deficit. PIFP is the current terminology for Atypical Facial Pain and is characterized by daily or near daily pain that is initially confined but may subsequently spread. Pain cannot be attributed to any pathological process, although traumatic neuropathic mechanisms are suspected. When present intraorally, PIFP has been termed ‘Atypical Odontalgia’, and this entity is discussed in a separate article in this special issue. PIFP is often a difficult but important differential diagnosis among chronic facial pain syndromes.

Aim

To summarize current knowledge on diagnostic criteria, differential diagnosis, pathophysiology and management of PIFP.

Methods

We present a narrative review reporting current literature and personal experience. Additionally, we discuss and differentiate the common differential diagnoses associated with PIFP including traumatic trigeminal neuropathies, regional myofascial pain, atypical neurovascular pains and atypical trigeminal neuropathic pains.

Results and conclusion

The underlying pathophysiology in PIFP is still enigmatic, however neuropathic mechanisms may be relevant. PIFP needs interdisciplinary collaboration to rule out and manage secondary causes, psychiatric comorbidities and other facial pain syndromes, particularly trigeminal neuralgia. Burden of disease and psychiatric comorbidity screening is recommended at an early stage of disease, and should be addressed in the management plan. Future research is needed to establish clear diagnostic criteria and treatment strategies based on clinical findings and individual pathophysiology.

Neuropathic orofacial pain: Facts and fiction

Definition and taxonomy This review deals with neuropathic pain of traumatic origin affecting the trigeminal nerve, i.e. painful post-traumatic trigeminal neuropathy (PTTN). Symptomatology The clinical characteristics of PTTN vary considerably, partly due to the type and extent of injury. Symptoms involve combinations of spontaneous and evoked pain and of positive and negative somatosensory signs. These patients are at risk of going through unnecessary dental/surgical procedures in the attempt to eradicate the cause of the pain, due to the fact that most dentists only rarely encounter PTTN. Epidemiology Overall, approximately 3% of patients with trigeminal nerve injuries develop PTTN. Patients are most often female above the age of 45 years, and both physical and psychological comorbidities are common. Pathophysiology PTTN shares many pathophysiological mechanisms with other peripheral neuropathic pain conditions. Diagnostic considerations PTTN may be confused with one of the regional neuralgias or other orofacial pain conditions. For intraoral PTTN, early stages are often misdiagnosed as odontogenic pain. Pain management Management of PTTN generally follows recommendations for peripheral neuropathic pain. Expert opinion International consensus on classification and taxonomy is urgently needed in order to advance the field related to this condition.

Continuous neurophatic orofacial pain: A retrospective study of 23 cases

Background

To determine the clinical characteristics of Continuous Neuropathic Orofacial Pain in patients that suffer Persistent Idiopathic Facial Pain (PIFP), Painful Post-Traumatic Trigeminal Neuropathy (PPTTN) or Burning Mouth Syndrome (BMS) and to describe their treatment.

Material and Methods

A retrospective observational study was made, reviewing the clinical history of the patients diagnosed with Continuous Neuropathic Orofacial Pain between 2004 and 2011 at the Orofacial Pain Unit of the Master of Oral Surgery and Implantology of the University of Barcelona and at the Orofacial Pain Unit of the Teknon Medical Center of Barcelona.

Results

The average age of the patients with Continuous Neuropathic Orofacial Pain was 54.5, with a clear female predominance (86.9%, n=20). Of all patients, 60.9% (n=14) were suffering a PIFP, 21.7% (n=5) had a BMS and 17.4% (n=4) were presenting a PPTTN. The pain quality described by the patients with Continuous Neuropathic Orofacial Pain was oppressive (43.47%, n=10), widely represented by patients with PIFP, and burning (39.13%, n=9) being the only quality that described patients with BMS. The treatment carried out with the patients was only pharmacologic. The most used drugs for the treatment of PIFP and PPTTN were clonazepam (50%, n=9) and amitriptyline (44.44%, n=8). However, a 55.5% (n=10) of the patients with PIFP or PPTTN required the association of two or more drugs for a correct pain control. All the patients with BMS responded satisfactorily to clonazepam.

Conclusions

Continuous Neuropathic Orofacial Pain is a little known condition among the general population, physicians and dentists. This favors a late diagnosis and inaccurate treatments which entail unnecessary suffering. It is important to inform both the general population and health professionals concerning this painful condition.

Key words:Continuous neuropathic orofacial pain, persistent idiopathic facial pain, painful post-traumatic trigeminal neuropathy, burning mouth syndrome, atypical odontalgia.

Amplified Brain Processing of Dentoalveolar Pressure Stimulus in Persistent Dentoalveolar Pain Disorder Patients

AIMS

(1) To determine the brain regions activated by dentoalveolar pressure stimulation in persistent dentoalveolar pain disorder (PDAP) patients, and (2) to compare these activation patterns to those seen in pain-free control subjects.

METHODS

A total of 13 PDAP patients and 13 matched controls completed the study. Clinical pain characteristics and psychosocial data were collected. Dentoalveolar mechanical pain thresholds were determined with a custom-made device over the painful area for patients and were used as the stimulation level during functional magnetic resonance imaging (fMRI) data acquisition. Control subjects received two stimulation levels over matched locations during fMRI scanning: one determined (as above) that evoked equally subjective pain ratings matching those of patients (subjective-pain match) and another nonpainful stimulation level matching the average stimulus intensity provided to patients (stimulus-intensity match). Clinical and psychosocial data were analyzed using independent samples t tests, Mann-Whitney U test, and Spearman rank-order correlation coefficient. fMRI data were analyzed using validated neuroimaging software and tested using a general linear model.

RESULTS

PDAP patients had greater anxiety (P<.0001) and depression scores (P=.001), more jaw function impairment (P<.0001), and greater social impact (P<.0001) than controls. No significant differences were found for brain activation spatial extent (PDAP X Controls subjective pain: P=.48; PDAP X Controls stimulus intensity: P=.12). Brain activations were significantly increased for PDAP patients compared to control subjects when matched to stimulus intensity in several regions related to the sensory-discriminative and cognitive components of pain perception, including the primary and secondary somatosensory cortices, inferior parietal lobule, insula, premotor cortex, prefrontal cortex, and thalamus. When matched to subjective pain ratings, increased brain activations were still present for PDAP patients compared to controls, although to a lesser extent.

CONCLUSION

The present results suggest that dentoalveolar pressure is processed differently in the brain of PDAP patients, and the increased activation in several brain areas is consistent with amplified pain processing.

Altered pain modulation in patients with persistent postendodontic pain

Persistent pain may follow nerve injuries associated with invasive therapeutic interventions. About 3% to 7% of the patients remain with chronic pain after endodontic treatment, and these are described as suffering from painful posttraumatic trigeminal neuropathy (PTTN). Unfortunately, we are unable to identify which patients undergoing such procedures are at increased risk of developing PTTN. Recent findings suggest that impaired endogenous analgesia may be associated with the development of postsurgical chronic pain. We hypothesized that patients with PTTN display pronociceptive pain modulation, in line with other chronic pain disorders. Dynamic (conditioned pain modulation, temporal summation) and static (response to mechanical and cold stimulation) psychophysical tests were performed intraorally and in the forearm of 27 patients with PTTN and 27 sex- and age-matched controls. The dynamic sensory testing demonstrated less efficient conditioned pain modulation, suggesting reduced function of the inhibitory endogenous pain-modulatory system, in patients with PTTN, mainly in those suffering from the condition for more than a year. The static sensory testing of patients with PTTN demonstrated forearm hyperalgesia to mechanical stimulation mainly in patients suffering from the condition for less than a year and prolonged painful sensation after intraoral cold stimulus mainly in patients suffering from the condition for more than a year. These findings suggest that PTTN is associated more with the inhibitory rather than the facilitatory arm of pain modulation and that the central nervous system has a role in PTTN pathophysiology, possibly in a time-dependent fashion.

Reliability of intra-oral quantitative sensory testing (QST) in patients with atypical odontalgia and healthy controls - a multicentre study

The reliability of comprehensive intra-oral quantitative sensory testing (QST) protocol has not been examined systematically in patients with chronic oro-facial pain. The aim of the present multicentre study was to examine test-retest and interexaminer reliability of intra-oral QST measures in terms of absolute values and z-scores as well as within-session coefficients of variation (CV) values in patients with atypical odontalgia (AO) and healthy pain-free controls. Forty-five patients with AO and 68 healthy controls were subjected to bilateral intra-oral gingival QST and unilateral extratrigeminal QST (thenar) on three occasions (twice on 1 day by two different examiners and once approximately 1 week later by one of the examiners). Intra-class correlation coefficients and kappa values for interexaminer and test-retest reliability were computed. Most of the standardised intra-oral QST measures showed fair to excellent interexaminer (9-12 of 13 measures) and test-retest (7-11 of 13 measures) reliability. Furthermore, no robust differences in reliability measures or within-session variability (CV) were detected between patients with AO and the healthy reference group. These reliability results in chronic orofacial pain patients support earlier suggestions based on data from healthy subjects that intra-oral QST is sufficiently reliable for use as a part of a comprehensive evaluation of patients with somatosensory disturbances or neuropathic pain in the trigeminal region.

Prevalence of persistent pain 3 to 5 years post primary root canal therapy and its impact on oral health-related quality of life: PEARL Network findings

INTRODUCTION

The frequency of persistent pain 3-5 years after primary root canal therapy and its impact on the patient's perceived oral health-related quality of life was determined in a practice-based research network.

METHODS

All patients presenting to participating network practices who received primary root canal therapy and restoration for a permanent tooth 3-5 years previously were invited to enroll. Persistent pain was defined as pain occurring spontaneously or elicited by percussion, palpation, or biting. The patient also completed an oral health-related quality of life questionnaire (Oral Health Impact Profile-14).

RESULTS

Sixty-four network practices enrolled 1323 patients; 13 were ineligible, 12 did not receive a final restoration, and 41 were extracted, leaving 1257 for analysis. The average time to follow-up was 3.9 ± 0.6 years. Five percent (63/1257) of the patients reported persistent pain, whereas 24 of 63 (38%) exhibited periapical pathosis and/or root fracture (odontogenic pain). No obvious odontogenic cause for persistent pain was found for 39 of 63 (62%). Teeth treated by specialists had a greater frequency of persistent pain than teeth treated by generalists (9.3% vs 3.0%, respectively; P < .0001). Sex, age, tooth type, type of dentist, and arch were not found to be associated with nonodontogenic persistent pain; however, ethnicity and a preoperative diagnosis of pulpitis without periapical pathosis were. Patients reporting pain with percussion tended to experience pain with other stimuli that negatively impacted quality of life including oral function and psychological discomfort and disability.

CONCLUSIONS

These results suggest that a small percentage (3.1%) of patients experience persistent pain not attributable to odontogenic causes 3-5 years after primary root canal therapy that may adversely impact their quality of life.

Biopsychosocial aspects of atypical odontalgia

Background. A few studies have found somatosensory abnormalities in atypical odontalgia (AO) patients. The aim of the study is to explore the presence of specific abnormalities in facial pain patients that can be considered as psychophysical factors predisposing to AO. Materials and Methods. The AO subjects (n = 18) have been compared to pain-free (n = 14), trigeminal neuralgia (n = 16), migraine (n = 17), and temporomandibular disorder (n = 14). The neurometer current perception threshold (CPT) was used to investigate somatosensory perception. Structured clinical interviews based on the DSM-IV axis I and DSM III-R axis II criteria for psychiatric disorders and self-assessment questionnaires were used to evaluate psychopathology and aggressive behavior among subjects. Results. Subjects with AO showed a lower Aβ, Aδ, and C trigeminal fiber pain perception threshold when compared to a pain-free control group. Resentment was determined to be inversely related to Aβ (rho: 0.62, P < 0.05), Aδ (rho: 0.53, P < 0.05) and C fibers (rho: 0.54, P < 0.05), and depression was inversely related with C fiber (rho: 0.52, P < 0.05) perception threshold only in AO subjects. Conclusion. High levels of depression and resentment can be considered predictive psychophysical factors for the development of AO after dental extraction.

Trigeminal neuralgia and persistent idiopathic facial pain

Trigeminal neuralgia (TN) and persistent idiopathic facial pain (PIFP) are two of the most puzzling orofacial pain conditions and affected patients are often very difficult to treat. TN is characterized by paroxysms of brief but severe pain followed by asymptomatic periods without pain. In some patients a constant dull background pain may persist. This constant dull pain sometimes makes the distinction from PIFP difficult. PIFP is defined as continuous facial pain, typically localized in a circumscribed area of the face, which is not accompanied by any neurological or other lesion identified by clinical examination or clinical investigations. The pain usually does not stay within the usual anatomic boundaries of the trigeminal nerve distribution and is a diagnosis of exclusion. Epidemiologic evidence on TN, and even more so on PIFP, is quite scarce, but generally both conditions are considered to be rare diseases. The etiology and underlying pathophysiology of TN, and more so PIFP, remain unknown. Treatment is based on only few randomized controlled clinical trials and insufficiently evaluated surgical procedures.

Current evidence on atypical odontalgia: diagnosis and clinical management

Patients with atypical odontalgia (AO) complain of medically unexplained toothache. No evidence-based diagnostic criteria or treatment guidelines are yet available. The present paper addresses seven clinical questions about AO based on current knowledge in the literature and discusses diagnostic criteria and guidelines for treatment and management. The questions are (i) What is the prevalence of AO in the community? (ii) What psychological problems are experienced by patients with AO? (iii) Are there any comorbidities of AO? (iv) Is local anesthesia effective for the relief of pain in AO? (v) Are there any characteristic symptoms of AO other than spontaneous pain? (vi) Are antidepressants effective for treatment of AO? (vii) Are anticonvulsants effective for treatment of AO? Our literature search provided answers for these questions; however, there is insufficient evidence-based data to establish guidelines for the diagnosis and treatment of AO. Overall, some diagnostic criteria for neuropathic pain and persistent dentoalveolar pain disorder may be applied to AO patients. The patient's psychogenic background should always be considered in the treatment and/or management of AO. The clinicians may need to treat AO patients using Patient-Oriented Evidence that Matters approach.

Plasma levels of milnacipran and its effectiveness for the treatment of chronic pain in the orofacial region

OBJECTIVES

This study was performed to assess the relationship between plasma levels of milnacipran and its analgesic/antidepressive effect in patients with chronic orofacial pain treated with this drug.

METHODS

A total of 44 patients took milnacipran for 12 weeks. Patients were assessed for their pain and depressive symptoms using the visual analog scale (VAS) and Hamilton Depression Rating Scale, respectively. The plasma milnacipran level was also assessed at week 12.

RESULTS

Forty patients completed study treatment and were included in the analysis. In these patients, the VAS score at week 12 significantly decreased from the baseline score (t = 5.15, p < 0.0001). The dose of milnacipran was positively correlated in a linear manner with the plasma level of the drug (Y = 44.86 + 0.33X, r = 0.54, R(2)  = 0.29, p = 0.0004). A quadratic regression curve was plotted between the percentage of decrease in the VAS score and plasma milnacipran level (Y = 27.39 + 0.76X - 0.008X(2) , p = 0.048, r = 0.40, R(2)  = 0.16). On the other hand, no significant relationship was noted between the percentage of decrease in the Hamilton Depression Rating Scale score and plasma milnacipran level.

CONCLUSION

The analgesic effect of milnacipran was suppressed in the presence of the plasma level of the drug outside the therapeutic range, whereas its antidepressant effect was not affected by its plasma level.

Persistent dento-alveolar pain disorder (PDAP): Working towards a better understanding

• New terminology, persistent dento-alveolar pain disorder (PDAP), and diagnostic criteria have been put forward to address the shortcomings of existing nomenclature, which are associated with unclear criteria. • Arriving at an accurate diagnosis of PDAP is based on excluding other possible aetiologies, and may involve different care providers. • Synthesis of published data suggests that PDAP has a frequency of occurrence following root canal therapy of around 1.6%. • The putative risk factors involved in PDAP are largely unknown, but seem to be similar to those being identified with other post-surgical chronic pain disorders. • The underlying mechanisms involved in the development of and/or perpetuating PDAP are unknown and the approach to treatment remains empiric in nature.

Classifying orofacial pains: a new proposal of taxonomy based on ontology

We propose a new taxonomy model based on ontological principles for disorders that manifest themselves through the symptom of persistent orofacial pain and are commonly seen in clinical practice and difficult to manage. Consensus meeting of eight experts from various geographic areas representing different perspectives (orofacial pain, headache, oral medicine and ontology) as an initial step towards improving the taxonomy. Ontological principles were introduced, reviewed and applied during the consensus building process. Diagnostic criteria for persistent dento-alveolar pain disorder (PDAP) were formulated as an example to be used to model the taxonomical structure of all orofacial pain conditions. These criteria have the advantage of being (i) anatomically defined, (ii) in accordance with other classification systems for the provision of clinical care, (iii) descriptive and succinct, (iv) easy to adapt for applications in varying settings, (v) scalable and (vi) transferable for the description of pain disorders in other orofacial regions of interest. Limitations are that the criteria introduce new terminology, do not have widespread acceptance and have yet to be tested. These results were presented to the greater conference membership and were unanimously accepted. Consensus for the diagnostic criteria of PDAP was established within this working group. This is an initial first step towards developing a coherent taxonomy for orofacial pain disorders, which is needed to improve clinical research and care.

Evaluation of a magnetic resonance-compatible dentoalveolar tactile stimulus device

Abstract

Background

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 [1] and to specialized structures (tongue, nasal mucosa, auricle, tympanic membrane, cornea and part of the conjunctiva) [2]. 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 [3-5]. 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) [6,7], 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 [8-10], but the majority of mechanism-based research of patients with AO has focused on the "peripheral aspect" [7].

Functional magnetic resonance imaging (fMRI) is an established research technique to study the central aspects of pain [11]. 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.

In the past few years several studies used fMRI to investigate the human trigeminal system [12,13], with a limited subset focusing on intraoral stimulation - specifically on the dentoalveolar processes, such as lip, tongue and teeth stimulation [14] or only teeth [15-17]. Some reasons for scarce literature on this topic may be the technical challenges involved in delivering facial/intraoral stimulation inside a MR scanner [17,18]: 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 [19], as reliability/reproducibility is a necessary feature of sensory testing [20].

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.