Two-stage method of free gingival graft prior to periodontal regenerative surgery for the treatment of intrabony defects with insufficient keratinised tissue width: a study protocol for an open-label randomised controlled trial.

INTRODUCTION: Guided tissue regeneration (GTR) combined with bone grafting for periodontal regenerative surgery has ideal clinical results for intrabony defect. However, some sites of intrabony defects often suffer from insufficient keratinised gingival width, which affects the efficacy and long-term prognosis of periodontal tissue regeneration. Free gingival graft (FGG) is an effective surgical procedure to widen the keratinised gingiva, but there are few clinical studies on FGG prior to GTR combination with bone grafting to improve clinical outcomes. METHODS: This study is an open-label randomised controlled trial. 68 patients with periodontitis with at least one intrabony defect depth with ≥3 mm are recruited and randomly grouped. In the test group, FGG is performed first, followed by GTR and bone grafting 3 months later; while in the control group, only periodontal tissue regenerative procedures are performed. After completion of all procedures, the patients will be recalled at 3 months, 6 months and 12 months and the relevant clinical and radiographic examinations will be carried out and statistical analysis of the data will also be performed. The present research has received approval from the Ethics Committee of Shanghai Stomatological Hospital (No.2022-007) on 4 August 2022. DISCUSSION: Exploring the effectiveness of the two-stage approach of FGG prior to periodontal tissue regenerative surgery for the treatment of keratinised gingival width deficient intrabony defects can provide a high-level evidence-based basis for the formulation of relevant treatment strategies in clinical practice. ETHICS AND DISSEMINATION: The present research has received approval from the Ethics Committee of Shanghai Stomatological Hospital (No.2022-007) on 4 August 2022. The patients will be incorporated into this trial only after their written informed consent has been obtained. The study will be performed according to the 2013 revision of the Helsinki Declaration of 1975. Personal information of all subjects will be stored in the Department of Periodontology of Shanghai Stomatological Hospital. Data of the present research will be registered with the Clinical Trials Registry Platform. Additionally, we will disseminate the results through scientific journals. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ID: ChiCTR 2200063180. Registered on 1 September 2022.

Connexin 43 contributes to temporomandibular joint inflammation induced-hypernociception via sodium channel 1.7 in trigeminal ganglion.

We previously demonstrated that sodium channel 1.7 (Nav1.7) in trigeminal ganglion (TG) was a critical factor in temporomandibular joint (TMJ) inflammation-induced hypernociception, but the mechanism underlying inflammation-induced upregulation of Nav1.7 remained unclear. Glial-neuron interaction plays a critical role in pain process and connexin 43 (Cx43), a gap junction protein expressed in satellite glial cells (SGCs) has been shown to play an important role in several pain models. In the present study, we investigate the role of Cx43 in TMJ inflammation-induced hypernociception and its possible impact on neuronal Nav1.7. We induced TMJ inflammation in rats by injecting complete Freund's adjuvant (CFA) into TMJ and observed a decrease in head withdraw threshold after 24 h. Electron microscopy showed morphological alterations of SGCs in TMJ-inflamed rats. The expression of Cx43, glial fibrillary acidic protein (GFAP), and Nav1.7 increased greatly compared with controls. In addition, pretreatment with Cx43 blockers in TMJ-inflamed rats could alleviate mechanical hypernociception, inhibit SGCs activation and IL-1ßrelease, and thus block the upregulation of Nav1.7. These findings indicate that the propagation of SGCs activation via Cx43 plays a critical role in Nav1.7-involved mechanical hypernociception induced by TMJ inflammation.