Chemical painful post-traumatic trigeminal neuropathy induced by dental bleaching: A case report.

Background: Teeth whitening is a frequent request in clinical practice. The most widely used whitening agent on vital teeth is carbamide peroxide. This article reports a rare adverse effect following a whitening procedure. Case description: A 29-year-old patient was referred to the dental emergency department for severe pain that exhibited the characteristics of neuropathic pain. In the absence of any visible lesion or traumatic event, this pain was linked to the recent application of carbamide peroxide (10%) during a bleaching procedure. The diagnosis of painful post-traumatic trigeminal neuropathy (PTTN) of chemical origin was made. Treatment with the anticonvulsant gabapentin (900mg per day) gradually reduced the pain until its complete disappearance. After presenting the clinical characteristics of the case, the pathophysiological hypotheses are discussed. Practical implications: Carbamide peroxide application may elicit nerve damage through a cascade of cellular and biological reactions, resulting in neuropathic pain. The successful management of this clinical case may provide useful information for similar situations. Key words:Case report, carbamide peroxide, painful neuropathy, pain, gingiva.

Dopamine Neuron Activity and Stress Signaling as Links Between Social Hierarchy and Psychopathology Vulnerability.

BACKGROUND: Social status in humans, generally reflected by socioeconomic status, has been associated, when constrained, with heightened vulnerability to pathologies including psychiatric diseases. Social hierarchy in mice translates into individual and interdependent behavioral strategies of animals within a group. The rules leading to the emergence of a social organization are elusive, and detangling the contribution of social status from other factors, whether environmental or genetic, to normal and pathological behaviors remains challenging. METHODS: We investigated the mechanisms shaping the emergence of a social hierarchy in isogenic C57BL/6 mice raised in groups of 4 using conditional mutant mouse models and chemogenetic manipulation of dopamine midbrain neuronal activity. We further studied the evolution of behavioral traits and the vulnerability to psychopathological-like phenotypes according to the social status of the animals. RESULTS: Higher sociability predetermined higher social hierarchy in the colony. Upon hierarchy establishment, higher-ranked mice showed increased anxiety and better cognitive abilities in a working memory task. Strikingly, the higher-ranked mice displayed a reduced activity of dopaminergic neurons within the ventral tegmental area, paired with a decreased behavioral response to cocaine and a decreased vulnerability to depressive-like behaviors following repeated social defeats. The pharmacogenetic inhibition of this neuronal population and the genetic inactivation of glucocorticoid receptor signaling in dopamine-sensing brain areas that resulted in decreased dopaminergic activity promoted accession to higher social ranks. CONCLUSIONS: Dopamine activity and its modulation by the stress response shapes social organization in mice, potentially linking interindividual and social status differences in vulnerability to psychopathologies.

Is burning mouth syndrome associated with stress? A meta-analysis.

BACKGROUND: Some studies have shown burning mouth syndrome (BMS) as comorbid psychosocial and psychiatric disorders, and as well, pointed at stress as a major risk factor. OBJECTIVE: The aim of this meta-analysis was to answer the following question: 'Is there an association between BMS and stress, compared to healthy controls?' METHODS: Two reviewers searched for the effect of stress in BMS and published on five main databases and three from the grey literature. Various questionnaires and biomarkers were analysed. Of the 2489 selected articles, 30 met the inclusion criteria. Studies englobed questionnaires, such as Perceived Stress Questionnaire, Lipp Stress Symptoms Inventory, Holmes-Rahe scale, Depression, Anxiety, and Stress Scale (DASS-21), Recent Experience Test; and various biomarkers, such as cortisol, opiorphin, IgA, α-amylase and interleukins. RESULTS: In all studies with questionnaires, stress was significantly increased in the BMS group vs. control. Patients with BMS presented 25.73% higher cortisol levels, 28.17% higher IgA levels and 40.62% higher α-amylase levels than controls. Meta-analysis found that BMS subjects presented 3.01 nmoL/L [0.53; 5.50] higher cortisol levels, 84.35 kU/L [15.00; 153.71] higher α-amylase levels, 29.25 mg/mL [9.86; 48.64] higher IgA levels and 258.59 pg/mL [59.24; 457.94] higher IL-8 levels than control. No differences were found for opiorphin concentration in ng/mL [-0.96; 2.53]. For interleukins, no differences were founded for IL-1 ß, IL-2, IL-4, IL-6, IL-8, IL-10 and TNF-α. CONCLUSION: Based on the available evidence, this meta-analysis suggests more stress factors in questionnaire-based studies, and higher levels of cortisol, α-amylase, IgA and IL-8 biomarkers in BMS subjects than controls.