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Macrophages are important for maintaining tissue homeostasis and defending against pathogens in periodontal tissues. However, these tissues are often vulnerable to damage due to local inflammatory responses within the host tissues. This study aimed to investigate the role of G protein-coupled receptor 91(GPR91) during the inflammatory response to Porphyromonas gingivalis (P. gingivalis) in bone marrow-derived macrophages (BMDMs). To this end, we examined expression levels of GPR91 genes in human periodontal tissues affected by periodontitis. Utilizing primary mouse BMDMs from wild-type (WT) and GPR91 knockout (GPR91−/−) mice infected with P. gingivalis, we demonstrated that GPR91 accumulates in inflamed gingival tissues. Additionally, P. gingivalis can induce intercellular succinate accumulation, inflammatory mediator generation, reactive oxygen species (ROS) production, lipid peroxidation, and superoxide dismutase activity in WT-BMDMs. Moreover, inhibition of GPR91 by the specific inhibitor 4C as well as knockdown of GPR91 reduced inflammation and oxidative stress in P. gingivalis-infected BMDMs. Furthermore, we discovered that GPR91-mediated inflammation in P. gingivalis-infected BMDMs is activated via the Erk/Nuclear Factor-κB pathway. These findings provide new insights into the metabolic pathogenesis of periodontal inflammation.

Abstract Background This study aimed to investigate the potential associations between alveolar bone thickness, bucco-palatal inclination of maxillary lateral incisors, and lateral incisor root resorption in patients with unilateral maxillary impacted canines (UMICs). Methods A total of three hundred and five subjects (120 males, 185 females; mean age, 16.39 years; standard deviation, 4.04) with UMICs were included. Canine position and root resorption were assessed using CBCT. UMICs were divided into palatal, buccal and mid-alveolus groups (PICs, BICs and MAICs), with 117, 137 and 51 subjects, respectively. Alveolar bone thickness and bucco-palatal inclination of lateral incisors were measured using the Dolphin software. Results The prevalence of lateral incisor root resorption was significantly lower in the BICs (13.9%) than MAICs (29.4%) and PICs (29.1%). Alveolar bone thickness of the apical area was smaller in UMICs with lateral incisor root resorption than no resorption in both PICs (8.33 ± 1.64 vs 10.53 ± 2.55 mm) and BICs (8.94 ± 1.85 vs 10.76 ± 2.28 mm). Furthermore, lateral incisors on the impacted side were more buccally inclined in PICs with lateral incisor root resorption than no resorption, while in both BICs and MAICs, there was no statistical difference between lateral incisor root resorption than no resorption. Moreover, alveolar bone thickness of the apical area, rather than bucco-palatal inclination of lateral incisors, was significantly correlated with lateral incisor root resorption both in PICs and BICs. Conclusions Lateral incisor root resorption is less common in BICs. Thinner alveolar bone thickness at the apical area of lateral incisors can be considered as a potential risk factor for lateral incisor root resorption in UMICs.

Abstract To investigate and compare the facial asymmetry (hard and soft tissues) among skeletal Class I, II, and III patients. A total of 221 subjects, including skeletal Class I (n = 80), skeletal Class II (n = 75), and skeletal Class III (n = 66), were included in the study. CBCT, 22 skeletal landmarks, and 10 soft tissue landmarks were used for the measurements and the asymmetry index was calculated to assess the facial asymmetry. Statistical analyses included one-way ANOVA, Kruskal–Wallis test, and Spearman correlation analysis. The skeletal Class III patients presented greater asymmetry than Class II patients for 10 hard tissue landmarks and 3 soft tissue landmarks (p 0.86). The ANS and Me in 21.3% patients deviated to contralateral sides. The skeletal Class III patients had more facial asymmetry than the Class II patients. Soft tissues showed similar asymmetry as the underlying hard tissues rather than a compensation of the hard tissue asymmetry. The inconsistency in the deviation of Me and ANS may exacerbate facial asymmetry.

ABSTRACTBackground Methionine adenosyl transferase II alpha (MAT2A) is the key enzyme to transform methionine into S-adenosylmethionine (SAM), the main methylgroup donor involved in the methylation. The purpose of our study wasto explore whether MAT2A-mediated methionine metabolism affected theexpression of inflammatory cytokines in human gingival fibroblasts(hGFs).Methods Both healthy and inflamed human gingiva were collected. HGFs werecultured and treated with P. gingivalis, with or without MAT2Ainhibitor (PF9366), small interference RNA (siRNA), or extrinsic SAMpretreatment. The levels of inflammatory cytokines were detected byreal-time PCR, western blotting, and ELISA. SAM levels were detectedby ELISA. The nuclear factor-kappa B (NF-κB) and mitogen-activatedprotein kinase (MAPK) pathway was explored by western blotting.Results The expression of MAT2A was increased in the inflamed tissues. P.gingivalis infection promoted the expression of MAT2A and SAM inhGFs. Meanwhile, PF9366 and MAT2A-knockdown significantly decreasedexpression of inflammatory cytokines and SAM production. PF9366inhibited activation of NF-κB/MAPK pathway in P. gingivalis-treatedhGFs.Conclusions MAT2A-mediated methionine metabolism promoted P. gingivalis-inducedinflammation in hGFs. Targeting MAT2A may provide a novel therapeuticmethod for modulating periodontitis.

This study aimed to investigate correlation between mitochondrial reactive oxygen species and Porphyromonas gingivalis in the process of cementoblast pyroptosis. Lactate dehydrogenase activity assay, enzyme-linked immunosorbent assay, western blotting and flow cytometry analysis were utilized to explore whether Porphyromonas gingivalis triggered pyroptosis in cementoblasts. Reactive oxygen species and mitochondrial reactive oxygen species were detected using flow cytometry and fluorescence staining. The effect of mitochondrial reactive oxygen species on the Porphyromonas gingivalis-induced pyroptosis of cementoblasts was assessed by Mito-Tempo, mitochondrion-targeted superoxide dismutase mimetic. Phosphorylation levels of p65 were measured by western blotting. SC75741, a nuclear factor-kappa B inhibitor, was added to block the nuclear factor-kappa B in the Porphyromonas gingivalis-infected cementoblasts. Porphyromonas gingivalis triggered pyroptosis of cementoblasts, and an elevation in reactive oxygen species generation in the mitochondria was observed. Inhibition of mitochondrial reactive oxygen species reduced pyroptosis and nuclear factor-kappa B signaling pathway mediated the pyroptotic cell death in Porphyromonas gingivalis-infected cementoblasts. Together, our findings demonstrate that mitochondrial reactive oxygen species increased by Porphyromonas gingivalis participated in the pyroptosis of cementoblasts. Targeting mitochondrial reactive oxygen species may offer therapeutic strategies for root surface remodeling or periodontal regeneration.

Abstract Background Gingival recession and post-operation discomfort are still a problem for patients receiving the periodontal regeneration surgery for intra-bony defects. To further reduce the trauma and the post-operation gingival recession, a novel periodontal endoscopy-aided non-incisional regeneration technique (NIT) was proposed in the treatment of intra-bony defects. Methods Retrospective analysis of 21 subjects treated with NIT and 21 subjects with periodontal endoscopy-aided scaling and root planing (PSRP) at baseline and 1-year evaluation was conducted. After removing the subgingival calculus and granulation tissue, bone grafting materials were placed into intrabony defects with the assistance of a gingival retractor in the NIT group. Probing depth (PD), gingival recession (GR), clinical attachment level (CAL), as well as the distance between bone crest (BC) level and base of the defect (BD) (intrabony defect depth, IBD) were evaluated at baseline and 1 year after treatment. Results At 1-year follow-up, the value of CAL, PD and IBD were statistically significant different compared with baseline in both two groups (p

Abstract Objective This retrospective study aimed to analyze the clinical efficacy of two regenerative surgical methods — Bio-Oss granules combined with barrier membranes and Bio-Oss Collagen alone — and to help clinicians achieve better periodontal regeneration outcomes in the specific periodontal condition. Methodology Patients who underwent periodontal regeneration surgery from January 2018 to April 2022 were retrospectively screened, and their clinical and radiographic outcomes at 6 months postoperatively were analyzed. The probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), gingival recession (GR), distance from the cemento-enamel junction to the bottom of the bone defect (CEJ-BD), and depth of intrabony defects (INFRA) were recorded before the operation (T0) and 6 months after it (T1), and subsequently compared. Results In total, 143 patients were included — 77 were placed in the Bio-Oss group and 66 were placed in the Bio-Oss Collagen group. All indicators, including PD and CAL at T1, showed significant differences compared to baseline, for both groups (P

Abstract Background To evaluate the incidence and severity of open gingival embrasures (OGEs) in adult patients treated with clear aligners and fixed appliances. Methods Two hundred non-extraction adult subjects with less than 5 mm of crowding (mean age, 24.6 ± 3.8 years) were enrolled in this retrospective study. The subjects were divided into the clear aligner (n = 100) and fixed appliance group (n = 100). The intraoral photographs were utilized to determine the incidence of OGEs in the upper arch between maxillary central incisors, as well as the lower arch between mandibular central incisors. Crown overlap, crown shape, posttreatment root angulation, the distance from the interproximal contact point (ICP) to the alveolar bone crest (ABC) after treatment and interproximal enamel reduction (IPR) were determined in the two groups. Results The incidence of OGEs between maxillary and mandibular central incisors after orthodontic treatment was 35.0% and 38.0% in the clear aligner group, respectively, significantly higher than that (18.0% and 24.0%) in the fixed appliance group (P

Abstract Background When infected with Porphyromonas gingivalis, gingival fibroblasts undergo metabolic reprogramming, and rely on aerobic glycolysis rather than oxidative phosphorylation for rapid energy replenishment. Hexokinases (HKs) are catalysts for glucose metabolism, and HK2 constitutes the major HK inducible isoform. The objective of this study is to determine whether HK2-mediated glycolysis promotes inflammatory responses in inflamed gingiva. Methods Levels of glycolysis-related genes were assessed in normal and inflamed gingiva. Human gingival fibroblasts were harvested and infected with Porphyromonas gingivalis in order to mimic periodontal inflammation. 2-deoxy-d-glucose, an analogue of glucose, was used to block HK2-mediated glycolysis, while small interfering RNA was used to knock down HK2 expression. The mRNA and protein levels of genes were analyzed by real-time quantitative PCR and western blotting, respectively. HK2 activity and lactate production were assessed by ELISA. Cell proliferation was assessed by confocal microscopy. The generation of reactive oxygen species was assessed by flow cytometry. Results Elevated expression of HK2 and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 was observed in the inflamed gingiva. P. gingivalis infection was shown to promote glycolysis in human gingival fibroblasts, as evidenced by increased gene transcription of HK2 and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3, cell glucose consumption, and HK2 activity. Inhibition and knockdown of HK2 resulted in reduced cytokine production, cell proliferation, and reactive oxygen species generation. Furthermore, P. gingivalis infection activated the hypoxia-inducible factor-1α signaling pathway, thus promoting HK2-mediated glycolysis and proinflammatory responses. Conclusions HK2-mediated glycolysis promotes inflammatory responses in gingival tissues, and therefore glycolysis can be targeted in order to inhibit the progression of periodontal inflammation.

Abstract The purpose of this study was to compare the difference of alveolar bone remodeling between the adolescents and adults in the maxillary incisor area during retraction. This retrospective study included 72 female patients who needed moderate anchorage to correct the bimaxillary protrusion. Subjects were further divided into the minor group (n = 36, 11–16 years old) and adult group (n = 36, 18–35 years old). Digital lateral cephalography and cone beam CT scanning were taken in each patient before (T0) and after treatment (T1). Cephalometry was conducted to assess incisor retraction, while alveolar bone thickness (ABT), alveolar bone distance (ABD), and alveolar bone area (ABA) were detected to assess changes in the alveolar bone. No difference in the inclination of upper incisors was observed at both T0 and T1 between two groups. Changes in the alveolar bone showed a similar tendency with bone apposition on the labial side and bone resorption on the palatal side in both groups. Less increase in the labial ABT (T1–T0) and more decrease in the palatal ABT (T1–T0) was found in the adult group, leading to less total ABT in the adult group. Higher reduction in ABD (T1–T0) was found in the adult group. Moreover, more decrease in the ABA (T1–T0) was found in the adult group. Adult patients have less alveolar bone support after treatment when compared with young adolescents. Orthodontists should take the age into consideration to reduce the potential periodontal risks during the treatment planning.

Background Microtubule dynamics plays a crucial role in the spatial arrangement of cell organelles and activation of the NLRP3 inflammasome. Purpose This study aimed to explore whether microtubule affinity regulating kinase 4 (MARK4) can be a therapeutic target of periodontitis by affecting microtubule dynamics and NLRP3 inflammasome-mediated pyroptosis in macrophages. Materials and Methods The NLRP3 inflammasome-related genes and MARK4 were measured in the healthy and inflamed human gingival tissues. Bone marrow-derived macrophages (BMDMs) were infected with Porphyromonas gingivalis, while the MARK4 inhibitors (OTSSP167 and Compound 50) and small interference RNA were utilized to restrain MARK4. Apoptosis-associated speck-like protein (ASC) speck was detected by confocal, and levels of interleukin-1β (IL-1β), as well as IL-18, were assessed by ELISA. Results Increased staining and transcription of MARK4, NLRP3, ASC, and Caspase-1 were observed in the inflamed gingiva. P. gingivalis infection promoted MARK4 expression and the NLRP3 inflammasome in BMDMs. Inhibition of MARK4 decreased LDH release, IL-1β and IL-18 production, ASC speck formation, and the pyroptosis-related genes transcription. Furthermore, MARK4 inhibition reduced microtubule polymerization and acetylation in P. gingivalis-infected BMDMs. Conclusions MARK4 promoted NLRP3 inflammasome activation and pyroptosis in P. gingivalis-infected BMDMs by affecting microtubule dynamics. MARK4 inhibition might be a potential target in regulating the NLRP3 inflammasome during periodontitis progress.

A 34-year-old man suffered from continuous suppuration at the mandibular second molar after orthodontic-orthognathic surgery. Several systemic anti-inflammatory and local antibiotic treatments were prescribed to arrest the infection, and the titanium plate at the right mandible was removed to avoid its contamination. However, such treatment modalities failed to control the infection, and the suppuration persisted. Periodontitis is a risk factor for infection after orthognathic surgery. Periodontal status should be thoroughly established in patients who need orthognathic surgery.