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Objective: The purpose of the study was to determine how the maxillary non-impacted third molars impact the distal region of alveolar bone of adjacent second molars. Method and materials: The periodontal condition of maxillary second molars for which the neighboring third molars were missing (NM3− group) and those with intact non-impacted third molars (NM3+ group) was analyzed in a retrospective study. Using CBCT, the patients were categorized based on the presence or absence of periodontitis, and the alveolar bone resorption parameters in the distal area of the second molars were measured. Results: A total of 135 patients with 200 maxillary second molars were enrolled in this retrospective study. Compared to the NM3− group, the second molars of the NM3+ group exhibited greater odds of increasing alveolar bone resorption in the distal region (health, OR = 3.60; periodontitis, OR = 7.68), regardless of the presence or absence of periodontitis. In healthy patients, factors such as female sex (OR = 1.48) and age above 25 years old (OR = 2.22) were linked to an elevated risk of alveolar bone resorption in the distal region of the second molars. In patients with periodontitis, male sex (OR = 3.63) and age above 45 years old (OR = 3.97) served as risk factors. Conclusions: Advanced age, sex, and the presence of non-impacted third molars are risk factors associated with alveolar bone resorption in individuals with adjacent second molars. In addition, the detrimental effects of non-impacted third molars in the population with periodontitis may be exacerbated. From a periodontal perspective, this serves as supportive evidence for the proactive removal of non-impacted third molars. Keywords: CBCT, non-impacted, periodontal pathology, second molars, third molars

Purpose: To study the clinical and pathological characteristics of oral lichen planus (OLP) in a large sample. Materials and Methods: A comprehensive analysis was conducted on 105 patients with oral lichen planus (OLP), considering various factors including sex, age, disease site, lesion type, lesion area, morphological characteristics, self-reported symptoms, and history of systemic diseases. Histopathological examination was performed for each patient, and the pathology results were analysed according to sex and age group. Results: 70.5% of the OLP patients were female, and OLP was most likely to occur in the cheek, followed by the tongue, lips, gums and palate. The patients with moderate pain according to the VAS score accounted for 60%. Thirty-nine percent of the OLP patients had a systemic disease, and the most common clinical type of OLP was nonerosive. Most of the pathological results showed liquefaction degeneration of basal cells and infiltration of lamina propria lymphocytes. There was no statistically significant difference in pathological manifestations between male and female patients, and there were statistically significant differences in pathological manifestations among different ages patients. Conclusion: This study analysed the sociodemographic data and clinical manifestations of 105 OLP patients to guide follow-up treatment planning and disease monitoring. Moreover, pathological manifestations should be analysed to avoid delayed treatment and to monitor for carcinogenesis. Furthermore, the correlation of pathological manifestations among OLP patients with different sexes and ages is conducive to further research on the specific differential manifestations and possible underlying mechanisms involved. Keywords: clinical features, demographic characteristics, histopathology, oral lichen planus

Purpose: To examine the relationship between socioeconomic inequalities and oral health among adults in the Guangxi province of China. Materials and Methods: The present work was designed as a cross-sectional study, and comprises a secondary analysis of the Fourth National Oral Health Survey from 2015–2016. A multistage cluster sampling method was adopted for this survey, conducted in three urban and three rural districts Guangxi province. Dental examinations were conducted to determine oral health indicators: decayed teeth (DT), clinical attachment loss (CAL) and missing teeth (MT). The outcome measures were DT, CAL and MT. A structured questionnaire was used to collect data on demographic characteristics and socioeconomic status (SES). Multiple logistic regression models were used to analyse the relationship between SES and oral health by adjusting covariates. Results: The sample consisted of 651 participants aged 35–74 years. Logisitic analysis showed a statistically significant association between SES and oral health indicators. In the fully adjusted model, participants with primary education were more likely to suffer more DT (OR = 2.67, 95% CI: 1.17–6.10), teeth with CAL ≥ 4 mm (OR = 2.15, 95% CI: 1.25–3.67) and MT (OR = 3.04, 95% CI: 1.65–5.60) compared to the higher education group. Participants with secondary education exhibited a higher likelihood of experiencing increased MT compared to those in the higher education group in the fully adjusted model (OR = 3.21, 95% CI: 1.78–5.76). Household income was associated with DT and MT in the unadjusted model only. Conclusions: There was strong relationship between SES and oral health of adults. The survey suggested a relationship between low educational attainment and oral health. Keywords: oral health, socioeconomic inequalities, socioeconomic status

Intentional replantation involves a combination of periodontics, endodontics, prosthodontics and oral surgery. Crown-root fracture management is still complicated nowadays. A fracture line extending longitudinally to the subgingival area and intruding bioogical width could affect infection control, gingival health and crown restoration. In the present study, we present two cases. Case 1 involved a 23-year-old man who presented at our hospital with crown-root fracture of the maxillary left central incisor. A radiographic image of the tooth revealed a fracture line under the alveolar crest. The fractured tooth was treated with intentional replantation with 180-degree rotation, root canal treatment and veneer restoration. The patient was followed up for 60 months. The replanted tooth functioned well, and no symptoms of resorption or ankylosis were observed by radiographic examination. Case 2 involved a 20-year-old woman who was referred to our hospital for crown-root fracture of her maxillary teeth. A radiographic examination revealed complicated crown-root fracture of the maxillary right lateral incisor and both maxillary central incisors. The central incisors were treated with intentional replantation with 180-degree rotation. At the 48-month follow-up, the fractured teeth were found to have regained normal function based on clinical and radiographic examination. Limited case reports are available on a long-term follow-up of intentional replantation with 180-degree rotation. These two cases, particularly case 2, presented optimal healing after 4 years with unideal crown–root ratios. This case report suggests that this old method of preserving teeth with crown-root fractures can be used as a last resort to save teeth owing to its timesaving and microinvasive procedure. Keywords: 180-degree rotation, crown-root fracture, intentional replantation

Objective: To understand the immune molecular landscapes of the two major costimulatory and coinhibitory pathways (B7 and TNFR families) in oral squamous cell carcinoma. Methods: The B7 family members (CD80, CD86, CD274, ICOSLG, CD276, VTCN1, NCR3LG1, HHLA2 and PDCD1LG2) and TNFR family members (TNFSF4, CD40, CD70, TNFSF9, TNFRSF14 and TNFSF18) were used to analyse the costimulatory and coinhibitory pathway alterations in oral squamous cell carcinoma. The online tools UCSC Xena and cBioPortal were used to derive oral squamous cell carcinoma patients' clinical parameters, mRNA levels, mutations, DNA copy number alterations and methylation levels. The correlations between mRNA levels and methylation levels were determined using Spearman's correlation analysis. A Kaplan-Meier survival analysis was performed to examine the relationships between mRNA expression levels and overall survival. Results: Compared with normal oral epithelial tissues, approximately 23.1% of patients showed upregulation of B7 expression and 15.3% showed upregulation of TNFR expression in oral squamous cell carcinoma, with CD274 (PD-L1) upregulation being the most common alteration. Mutations and copy number alterations were shown to have little effect on B7 and TNFR expression. The mRNA levels of B7 and TNFR genes were negatively correlated with their methylation levels. Furthermore, oral squamous cell carcinoma patients with high expression levels of CD274 showed poor overall survival, while those with high expression levels of CD276 or HHLA2 showed good clinical outcomes. Conclusion: This study elucidated the molecular landscapes of the B7 and TNFR genes in oral squamous cell carcinoma, which could provide a novel strategy for clinical therapy. Keywords: B7, genomic alteration, oral squamous cell carcinoma, survival, TNFR

This meta-analysis aims to compare the effect of the application of enamel matrix derivative (EMD) used alone with that of its use in combination with alloplastic materials in the treatment of periodontal intrabony defects. Relevant studies were retrieved from PubMed, the Cochrane Library, and Embase through November 2015. The main clinical outcomes were pocket probing depth (PPD) reduction, clinical attachment level (CAL) gain, gingival recession (REC) increase, and defect fill gain. Two separate meta-analyses were performed according to the length of follow-up. Nine articles were included. The results demonstrated that in the short-term follow-up group (≤ 1 year), in terms of PPD reduction (P .05) and REC increase (P .05), the application of an EMD combined with alloplastic materials provided advantages compared to EMD used alone. For CAL gain (P = .17) and gain of defect fill (P = .07), no significant differences were observed. In the long-term follow-up group (> 1 year), no significant differences in terms of REC increase (P = .05) were found between the groups, but combined therapy exhibited an advantage in terms of PPD reduction (P .05), CAL gain (P .05), and gain in defect fill (P .05). Within its limitations, this meta-analysis indicated that the additional benefit of combined therapy in the treatment of periodontal intrabony defects compared with EMD used alone cannot be proven.

Purpose: Artificial materials such as dental implants are at risk of bacterial contamination in the oral cavity. Human beta defensins (HBDs), small cationic antimicrobial peptides that exert a broad-spectrum antibacterial function at epithelial surfaces and within some mesenchymal tissues, could probably help to reduce such contamination. HBDs also have protective immunomodulatory effects and have been reported to promote bone remodeling. The aim of this study, therefore, was to investigate the influence of recombinant HBD-2 on the proliferation and survival of cells in culture. Materials and Methods: Human mesenchymal stem cells (hMSCs), human osteoblasts, human keratinocytes (control), and the HeLa cancer cell line (control) were incubated with recombinant HBD-2 (1, 5, 10, or 20 µg/mL). Cell proliferation and cytotoxicity were evaluated via a water-soluble tetrazolium salt (WST-1) and lactate dehydrogenase assays, respectively. Results: HBD-2 was not toxic in any tested concentration to hMSCs, osteoblasts, keratinocytes, or HeLa cells. Furthermore, proliferation of hMSCs and osteoblasts increased after treatment with HBD-2 at all tested concentrations, and keratinocyte proliferation increased when treated at 20 µg/mL. In contrast, HeLa cancer cells were not affected by HBD-2 as tested. Conclusions: HBD-2 is not only biocompatible but also promotes proliferation of hMSCs, osteoblasts, and keratinocytes in culture. Further investigation of HBD-2 functional surface coating of artificial materials is recommended. Keywords: antimicrobial peptides, biocompatibility, human beta defensins, human mesenchymal stem cells, human primary osteoblasts, implant dentistry

Purpose: Human mesenchymal stem cells (hMSCs) hold the potential for bone regeneration because of their self-renewing and multipotent character. The goal of this study was to evaluate the influence of collagen membranes on the proliferation of hMSCs derived from bone marrow. A special focus was set on short-term eluates derived from collagen membranes, as volatile toxic materials washed out from these membranes may influence cell behavior during the short time course of oral surgery. Materials and Methods: The proliferation of hMSCs seeded directly on a collagen membrane (BioGide) was evaluated quantitatively using the cell proliferation reagent WST-1 (4-3-[4-iodophenyl]-2-[4-nitrophenyl]-2H-[5-tetrazolio]-1, 3--benzol-disulfonate) and qualitatively by scanning electron microscopy. Two standard biocompatibility tests, namely the lactate dehydrogenase and MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazoliumbromide) tests, were performed using hMSCs cultivated in eluates from membranes incubated for 10 minutes, 1 hour, or 24 hours in serum-free cell culture medium. The data were analyzed statistically. Results: Scanning electron microscopy showed large numbers of hMSCs with well-spread morphology on the collagen membranes after 7 days of culture. The WST test revealed significantly better proliferation of hMSCs on collagen membranes after 4 days of culture compared to cells cultured on a cover glass. Cytotoxicity levels were low, peaking in short-term eluates and decreasing with longer incubation times. Conclusion: Porcine collagen membranes showed good biocompatibility in vitro for hMSCs. If maximum cell proliferation rates are required, a prewash of membranes prior to application may be useful. Keywords: biocompatibility, collagen membrane, guided bone regeneration, human mesenchymal stem cells

Objective: To evaluate attachment and proliferation of human gingival fibroblasts (HGFs), human periodontal ligament fibroblasts (HPDLFs) and human osteoblasts (HOBs) on diseased root surfaces of human teeth demineralised with EDTA and subsequently treated with freshly prepared platelet-rich plasma (PRP) or platelet-poor plasma (PPP) from human blood. Methods: HGFs, HPDLFs and HOBs were grown from tissue explants. Human whole blood from healthy subjects was collected to prepare PRP and PPP. The root surfaces of periodontitis- affected teeth were scaled, sectioned, and demineralised with EDTA and treated with PPP or PRP or none. The control group was neither demineralised nor treated with PPP or PRP. The cementum surfaces of root slices were cultured with HGFs, HPDLFs or HOBs for 24 or 48 h. Attachment and proliferation of cells were evaluated using cell count, scanning electron microscopy and MTT assay. Results: The root surfaces of the control group demonstrated the least number of attached cells. Demineralisation alone or combined with PRP or PPP increased cell attachment and proliferation. Electron microscopic evaluation further confirmed that both PRP and PPP significantly enhanced cell attachment to the diseased root surfaces. Conclusion: Pretreatment of diseased human root surfaces with EDTA, PRP or PPP enhances the attachment and proliferation of HGFs, HPDLFs and HOBs to the diseased root surface. Keywords: periodontal cells, attachment, platelet-rich plasma, platelet-poor plasma, demineralisation

Purpose: The aim of this study was to compare the clinical performance of metal-ceramic crowns made with an experimental alloy prepared by the Nordic Institute of Dental Materials, containing 15% zirconium and 85% titanium (Ti-15% Zr), and a high noble gold-palladium alloy (Mattikraft). Materials and Methods: Twenty patients who satisfied the inclusion criteria were selected sequentially from the departmental waiting list. Each patient received 2 crowns in the premolar or molar region. Which tooth was to receive a crown based on gold-palladium alloy or Ti-15% Zr alloy was randomly decided. A number of aspects indicating the clinical performance of the crowns were recorded at baseline and after 1, 2, and 3 years. Results: No statistically significant differences between the 2 types of crowns were demonstrated regarding overall technical evaluation, occurrence of plaque, bleeding on probing, or patient satisfaction. Periodontal pocket measurements around Ti-15% Zr crowns were significantly higher than those around gold alloy crowns. However, a similar difference also existed at baseline. Periodontal pocket measurements increased and patient satisfaction improved significantly over time. Conclusions: Within the limitations of this study, the results indicate that there is no difference in the clinical performance of crowns based on Ti-15% Zr or gold-palladium alloy.