Association between lipid metabolism and periodontitis in obese patients: a cross-sectional study.

BACKGROUND: To investigate the association between clinical periodontal parameters of periodontitis, serum lipid metabolism markers and adipokines' levels in patients with obesity and periodontitis. METHODS: A total of 112 patients admitted to Hospital of Xi'an Jiaotong University were included in this study. They were divided into normal body weight group (18.5 < body mass index, BMI < 25, n = 36), overweight group (25 ≤ BMI < 30, n = 38), and obesity group (BMI ≥ 30, n = 38) accordingly. The diagnosis of periodontitis was based on the newest international classification of periodontitis. Full-mouth clinical periodontal measurements included: plaque index, periodontal pocket depth, clinical attachment level, and bleeding on probing. Gingival crevicular fluid samples were analyzed for: Interleukin-1ß, tumor necrosis factor-α, Interleukin-6 and C-reactive protein. Serum triglycerides, total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol and glycosylated hemoglobin levels were measured. Visfatin, leptin, resistin, and adiponectin levels in serum were also measured. RESULTS: The ratio of participants without periodontitis was significantly highest in normal weight group, and the proportion of severe periodontitis (stage III and IV) was highest in obesity group. The periodontal pocket depth, clinical attachment level, and the inflammatory cytokines in gingival crevicular fluid in obesity group and overweight group were higher than those in normal body weight group. The BMI and waist-to-hip ratio (WHR) were significantly positive correlated with periodontal pocket depth and clinical attachment level. Using a Multivariate logistic regression model, periodontitis correlates to BMI, WHR, serum levels of triglyceride, total cholesterol, low density lipoprotein, and adipokines such as visfatin, leptin, and resistin. CONCLUSIONS: Obesity is positively correlated with the aggravation of periodontitis. Obesity may aggravate the damage to periodontal tissue by regulating the secretion level of adipokines.

Increased expression of TRPV1 in the trigeminal ganglion is involved in orofacial pain during experimental tooth movement in rats.

To investigate whether transient receptor potential vanilloid type 1 (TRPV1) is involved in pain induced by experimental tooth movement, experiments were performed in male Sprague-Dawley rats weighing 200-250 g. Directed face-grooming behavior was used to evaluate nocifensive behavior in rats during experimental tooth movement. The distribution of TRPV1 in the trigeminal ganglion (TG) was evaluated by immunohistochemistry, and its expression was detected by western blotting at several time points following the application of various magnitudes of force during tooth movement. Immunohistochemical analysis revealed that TRPV1 was expressed in TG, and its expression was increased after experimental tooth movement. Western blot results also showed that experimental tooth movement led to a statistically significant increase in expression of TRPV1 protein in TG. Meanwhile, the time spent on directed face-grooming peaked on day 1 and thereafter showed a gradual decrease. In addition, both the change in TRPV1 expression in the TG and directed face-grooming behavior were modulated in a force-dependent manner and in concert with initial orthodontic pain responses. Our results reveal that TRPV1 expression is modulated by experimental tooth movement and is involved in tooth-movement pain.

Effect of acetaminophen on relieving orthodontic pain with clear aligner based on GAD-7: A retrospective research.

Objectives: Patients may have uncomfortable feelings during orthodontic treatment, which can directly lead to dissatisfaction. So in order to improve the patient's sense of pleasure during the treatment, it would be of great benefit if orthodontic pain can be relieved. Materials and methods: We included 150 patients wearing clear aligners from 18 to 30 years old during 2018-2020. Then designed following groups to determine the effectiveness of both verbal behavior modification and combination therapy with acetaminophen in reducing treatment pain: Group A, generalized anxiety disorder 7 (GAD-7) scored 0-4; Group B, GAD-7 scored 5-9; Group C, GAD-7 scored 10-14; and Group D, GAD-7 scored 15-21. Results: There was a difference in the visual analog scale (VAS) between verbal behavior modification with and without a 300-mg acetaminophen tablet oral QD in Group A (received the intervention at 8 h and 1 d), Group B at 8 h and 1 d, Group C at 8 h, 1 d, 2 d, and 3 d, and Group D at 8 h, 1 d, 2 d, 3 d, and 4 d. After 8 h, 1 d, 2 d, 3 d, and 4 d in patients with verbal behavior modification, VAS was markedly increased in Group D compared with Group A, B and C. Furthermore, after 8 h and 1 d in patients with verbal behavior modification and 300-mg acetaminophen tablet oral QD, VAS was strongly enhanced in Group D. Conclusions: Dental anxiety is strongly associated with pain in orthodontic patients receiving clear aligners. Acetaminophen administration may be a benefit in orthodontic pain that results from clear aligners, especially in the group with more GAD-7.

The central nucleus of the amygdala lesion attenuates orthodontic pain during experimental tooth movement in rats.

INTRODUCTION: Orthodontic pain is the most common adverse side effect reported in the context of tooth movement. Given its central role in processing pain and negative emotion, the central nucleus of the amygdala (CeA) is thought to be a key site involved in orthodontic pain sensation. METHODS: In the present study, we therefore explored whether the CeA is involved in contributing to orthodontic pain in a rat model of tooth movement. For this study, we utilized adult male rats with bilateral sham or electrolytic CeA lesions (400 µA; 25 s), and then we analyzed face grooming behavior as a measure of pain sensation. RESULTS: Through this approach, we found that there were time- and force-dependent factors influencing pain levels in these rats. We further found that bilateral CeA lesions markedly reduced tooth movement-induced orofacial pain and that unilateral CeA lesions did so to a lesser extent. CONCLUSIONS: As such, these results suggest the CeA is a key area of orthodontic pain, with the results of this study highlighting potential avenues for achieving pain relief in those suffering from orthodontic pain.

Elevated osteogenic potential of stem cells from inflammatory dental pulp tissues by Wnt4 overexpression for treating bone defect in rats.

BACKGROUND: The osteogenic capacity of inflammatory dental pulp stem cells (DPSCs-IPs) is reported lower than that of normal dental pulp stem cells (DPSCs-NPs). Down-regulation of Wnt4 may be the key factor affecting the osteogenic ability of DPSCs-IPs. In order to prove that the restoration of Wnt4 expression could improve the osteogenic potential of DPSCs-IPs, Wnt4 overexpressed inflammatory dental pulp stem cells (Wnt4-DPSCs-IPs) were performed to reconstruct bone defects in rats. METHODS: Human DPSCs-IPs were cultured and transfected with Wnt4 overexpression lentiviral vector. Stem cell characterization was performed by flow cytometry and induction of multidirectional differentiation. Wnt4-DPSCs-IPs were loaded onto poly (hydroxybutyrate-co-valerate) (PHBV). The compounds were engrafted into artificially-created defect in alveolar bone. The effectiveness of Wnt4-DPSCs-IPs/PHBV in bone regeneration was assessed by micro-CT and immunohistochemical staining of osteocalcin, a representative osteogenic marker. RESULTS: Collecting data showed that Wnt4 overexpression didn't change stem cell characteristics of DPSCs-IPs. Wnt4-DPSCs-IPs retain osteogenic, adipogenic and chondrogenic differentiation abilities. Wnt4-DPSCs-IPs/PHBV were more effective than DPSCs-IPs/PHBV in repair of rat bone defects by 3 months' post-surgical reconstruction. CONCLUSIONS: Restoration of Wnt4 expression could improve the osteogenic potential of DPSCs-IPs. Wnt4 restored DPSCs-IPs may be a feasible resource of seed cells for bone regeneration in future clinical application.

Loss of Wnt4 expression inhibits the odontogenic potential of dental pulp stem cells through JNK signaling in pulpitis.

Dental pulp stem cell (DPSC)-based odontogenic regeneration in inflammatory conditions is important in the process of pulpitis. DPSCs have been reported to lose potential for odontogenic regeneration in inflammatory conditions. This study aims to determine the mechanism of impaired odontogenic differentiation of DPSCs in an inflammatory microenvironment. We regulated Wnt4 expression using recombinant lentiviral Wnt4 and Wnt4 siRNA. Alkaline phosphatase (ALP) and Alizarin red S (ARS) staining as well as Real-Time PCR were performed to evaluate the osteogenic differentiation potential of DPSCs with either upregulated or downregulated Wnt4. Furthermore, SP600125 was used to inhibit the potential downstream factor JNK1, and the osteogenic differentiation ability of DPSCs was evaluated. As shown, Wnt4 was downregulated in DPSCs under inflammatory conditions. Inhibition of Wnt4 expression in DPSCs negatively regulated odontogenic differentiation. Overexpression of Wnt4 in LPS-treated DPSCs promoted odontogenic differentiation. In addition, JNK1 was responsible for Wnt4-mediated odontogenic differentiation of DPSCs. Taken together, Wnt4 may function by affecting JNK signaling pathways in the process of impaired odontogenic regeneration by DPSCs under inflammatory conditions.

Blocking of TRPV-1 in the parodontium relieves orthodontic pain by inhibiting the expression of TRPV-1 in the trigeminal ganglion during experimental tooth movement in rats.

Orthodontic pain has confused the orthodontics for a long time, and recent research demonstrated that transient receptor potential vanilloid type 1 (TRPV1) had crucial functions in transduction of painful stimuli. The present research investigated the analgesia effects of the blocking TRPV1 on orthodontic pain during experimental tooth movement. Under challenge with experimental tooth movement, the expression of TRPV1 in the parodontium was increased in a time-dependent and force-dependent manner. And treatment with selective TRPV1 antagonist AMG-9810 in the parodontium reduced the expression of TRPV1 in the trigeminal ganglion (TG) and decreased the secretion of IL-1ß in the gingival crevicular fluid. Furthermore, AMG-9810 could relieve orthodontic pain arising from experimental tooth movement in rats. We suggest that TRPV1 both in the parodontium and trigeminal ganglion are involved in orthodontic pain, and TRPV1 in the parodontium influence on orthodontic pain through reducing the expression of TRPV1 in trigeminal ganglion. Our finding may help to develop strategies for relieving orthodontic pain after orthodontics.

[Expression of TRPV1 and CGRP in rat trigeminal ganglion during orthodontic tooth movement].

PURPOSE: Sprague-Dawley rat models of tooth movement were established to investigate the expression of transient receptor potential vanilloid 1 (TRPV1) and calcitonin gene related peptide (CGRP) in rat trigeminal ganglion during orthodontic tooth movement, and to explore the roles of TRPV1 and CGRP in orthodontic pain. METHODS: Sixty-six Sprague-Dawley rats were randomly divided into control group (n=6), sham operation group (n=6), and experimental group (n=54). Tooth movement models were established, orthodontic force (50 g) was applied on the maxillary first molar in the rats of experimental group, and then the trigeminal ganglia were collected at 4, 8 h, 1 d (3 subgroups were set up according to the force: 1 d-30 g, 1 d-50 g, 1 d-80 g), 3, 5, 7, 14 d after tooth movement. The changes of TRPV1 and CGRP expression were detected by immunofluorescence staining. SPSS16.0 software package was used for statistical analysis. RESULTS: According to immunofluorescence staining, the TRPV1-IR and CGRP-IR neurons were mostly small to medium sized. The percentages of TRPV1-IR and CGRP-IR neurons in trigeminal ganglion increased after applying force, and reached the peak at 1-3 d and then fell to the initial level gradually. In addition, the application of greater force during experimental tooth movement induced higher percentages of TRPV1-IR and CGRP-IR neurons in trigeminal ganglion. CONCLUSIONS: Experimental tooth movement leads to the regular changes of TRPV1-IR and CGRP-IR neurons in trigeminal ganglion, indicating that TRPV1 and CGRP may play important roles in orthodontic pain.

Bone regeneration by nanohydroxyapatite/chitosan/poly(lactide-co-glycolide) scaffolds seeded with human umbilical cord mesenchymal stem cells in the calvarial defects of the nude mice.

In the preliminary study, we have found an excellent osteogenic property of nanohydroxyapatite/chitosan/poly(lactide-co-glycolide) (nHA/CS/PLGA) scaffolds seeded with human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro and subcutaneously in the nude mice. The aim of this study was to further evaluate the osteogenic capacity of nHA/CS/PLGA scaffolds seeded with hUCMSCs in the calvarial defects of the nude mice. Totally 108 nude mice were included and divided into 6 groups: PLGA scaffolds + hUCMSCs; nHA/PLGA scaffolds + hUCMSCs; CS/PLGA scaffolds + hUCMSCs; nHA/CS/PLGA scaffolds + hUCMSCs; nHA/CS/PLGA scaffolds without seeding; the control group (no scaffolds) (n = 18). The scaffolds were implanted into the calvarial defects of nude mice. The amount of new bones was evaluated by fluorescence labeling, H&E staining, and Van Gieson staining at 4 and 8 weeks, respectively. The results demonstrated that the amount of new bones was significantly increased in the group of nHA/CS/PLGA scaffolds seeded with hUCMSCs (p < 0.01). On the basis of previous studies in vitro and in subcutaneous implantation of the nude mice, the results revealed that the nHA and CS also enhanced the bone regeneration by nHA/CS/PLGA scaffolds seeded with hUCMSCs in the calvarial defects of the nude mice at early stage.

[The change of transient receptor potential vanilloid-1 and interleukin-1α in periodontal tissue during experimental tooth movement].

PURPOSE: To investigate the expression of TRPV1 and IL-1α in Sprague-Dawley rats' periodontal ligament (PLD) during experimental tooth movement of different orthodontic force and duration, and explore the role of TRPV1 and IL-1α in orthodontic pain. METHODS: 66 Sprague-Dawley rats were divided into control group (n=6), sham operation group (n=6) and experimental group (n=54) randomly. Orthodontic force was applied on right first maxillary molar in rats and the changes of TRPV1 and IL-1α expression were detected by real-time PCR at 4 h, 8 h, 1 d (three subgroups were added according to different forces: 1 d-30 g, 1 d-50 g, 1 d-80 g ), 3 d, 5 d, 7 d, 14 d after tooth movement. The data was analyzed using SPSS 13.0 software pakage. RESULTS: Following the experimental tooth movement, the expression of TRPV1 and IL-1α in periodontal tissues were significantly up-regulated from 4 h to 7 d, with a peak at 1 d and returned to normal level at 1 week. The greater force applied during experimental tooth movement at 1 d, the higher expression of TRPV1 and IL-1α were detected in periodontal tissues. CONCLUSIONS: Experimental tooth movement leads to regular change of TRPV1 and IL-1α expression in periodontal tissues, which indicates that TRPV1 and IL-1α may play an important role in orthodontic pain.

[The change of calcitonin gene- related peptide in periodontal tissue during orthodontic tooth movement].

PURPOSE: To establish a Sprague-Dawley rat model of tooth movement, detect the expression of calcitonin gene-related peptide (calcitonin gene related peptide, CGRP) in Sprague-Dawley rats' periodontal tissues during tooth movement and explore the role of the peripheral mechanisms of pain in orthodontics. METHODS: 60 Sprague-Dawley rats were randomly divided into experimental group (n=54) and control group (n=6). Force was applied on right maxillary first molar in rats and the changes of CGRP expression were detected by real-time PCR 4 h, 8 h, 1 d, 3 d, 5 d, 7 d, 14 d after tooth movement. SPSS 13.0 software package was selected and one-way ANOVA (least significant difference, LSD) was used for statistics analysis. RESULTS: Experimental tooth movement led to an increase in the expression of CGRP. In addition, following experimental tooth movement, the expression of CGRP in periodontal tissues was significantly up-regulated from 4 h, with a peak on 1d and returned to the control level at 2-week. 1 d after experimental tooth movement, the application of different forces to rats induced a significant increase in CGRP expression. CONCLUSION: The regular change of CGRP expression in periodontal tissues indicates that CGRP may play an important role in peripheral mechanism of orthodontic pain.