Analgesic effect of gum chewing in patients with burning mouth syndrome

Duloxetine improves chronic orofacial pain and comorbid depressive symptoms in association with reduction of serotonin transporter protein through upregulation of ubiquitinated serotonin transporter protein

ABSTRACT

Chronic orofacial pain (COP) is relieved by duloxetine (DLX) and frequently causes depressive symptoms. The aim of this study was to confirm effects of DLX on pain and depressive symptoms, and to associate with their effectiveness in platelet serotonin transporter (SERT) expression, which is a target molecule of DLX and plasma serotonin concentration in COP patients with depressive symptoms. We assessed for the severity of pain and depressive symptoms using the Visual Analog Scale (VAS) and 17-item Hamilton Depression Rating Scale (HDRS), respectively. Chronic orofacial pain patients were classified into 2 groups based on their HDRS before DLX-treatment: COP patients with (COP-D) and without (COP-ND) depressive symptoms. We found that the VAS and HDRS scores of both groups were significantly decreased after DLX treatment compared with those before DLX treatment. Upregulation of total SERT and downregulation of ubiquitinated SERT were observed before DLX treatment in both groups compared with healthy controls. After DLX treatment, there were no differences in total SERT of both groups and in ubiquitinated SERT of COP-D patients compared with healthy controls; whereas, ubiquitinated SERT of COP-ND patients remained downregulated. There were positive correlations between changes of serotonin concentrations and of VAS or HDRS scores in only COP-D patients. Our findings indicate that DLX improves not only pain but also comorbid depressive symptoms of COP-D patients. Duloxetine also reduces platelet SERT through upregulation of ubiquitinated SERT. As the result, decrease of plasma serotonin concentrations may be related to the efficacy of DLX in relieving pain and depression in COP patients.

Effect of chewing gum on orthodontic pain in patients receiving fixed orthodontic treatment: a systematic review and meta-analysis

OBJECTIVES

The objective of this systematic review and meta-analysis was to evaluate the effect of chewing gum on orthodontic pain and to determine the rate of bracket breakage associated with fixed orthodontic appliances.

METHODS

This review and its reporting were performed according to the Cochrane Handbook for Systematic Reviews of Interventions and the PRISMA guidelines. Six electronic databases were searched up to March 16, 2023, to identify relevant studies that met the inclusion and exclusion criteria. Furthermore, grey literature resources were searched. The Cochrane Collaboration Risk of Bias tool 2 was used to assess the quality of the included studies. Meta-analysis was conducted using RevMan, and sensitivity analysis and publication bias analysis were performed using STATA software. GRADE tool was used to evaluate the certainty of evidence.

RESULTS

Fifteen studies with 2116 participants were ultimately included in this review, and 14 studies were included in the meta-analysis. Compared with the blank group, chewing gum had a significant pain relieving effect at all times after fixation of the initial archwire (P ≤ 0.05). No significant difference was found between the chewing gum group and the analgesics group at any timepoints (P > 0.05). Only four studies evaluated the rate of bracket breakage and revealed that chewing gum did not increase the rate of bracket breakage. The sensitivity analysis showed that there was no significant difference in the pooled outcomes after the included studies were removed one at times, and Egger analysis revealed no significant publication bias in included studies (P > 0.05).

CONCLUSIONS

Chewing gum is a non-invasive, low-cost and convenient method that has a significant effect on relieving orthodontic pain and has no effect on the rate of bracket breakage. Therefore, chewing gum can be recommended as a suitable substitute for analgesics to reduce orthodontic pain.