Tobacco Use and Oral Health

Dental staff and patient attitudes about nicotine replacement therapy samples in dental care: A National Dental Practice-Based Research Network study

OBJECTIVES

Cigarette smoking negatively affects oral health. Nicotine replacement therapies (NRT; e.g. nicotine patch or lozenge) and brief interventions (e.g. Ask-Advise-Refer; AAR) can improve cessation outcomes but are underutilized. NRT sampling (NRTS) increases NRT utilization by providing patients with samples of NRT as part of routine healthcare. Ask-Advise-Refer is a brief intervention where practitioners: ask patients about tobacco use, advise those using tobacco to quit and refer to the state quit line. The objective of this qualitative study was to explore dental care practitioners' and patients' attitudes and experiences regarding tobacco cessation treatment and perceptions of two brief intervention models, assessed separately: NRTS and AAR.

METHODS

Twenty-four dental care practitioners and nine patients, recruited through the National Dental Practice-Based Research Network, participated in semi-structured telephone interviews. Interviews assessed experiences with tobacco use intervention and attitudes towards NRTS and AAR. Thematic analysis identified emergent themes related to feasibility and acceptability of NRTS and AAR.

RESULTS

Practitioners varied on how they address tobacco use, from systematically to idiosyncratically. Some practitioners recommend NRT; few had prescribed it. Practitioners had favourable attitudes towards AAR and NRTS, with most believing that both interventions would be acceptable and feasible to implement. Concerns regarding AAR were time and patient resistance to discussing tobacco use. Concerns regarding NRTS were patient resistance to using NRT, side effects or medication interactions, and capacity to provide follow-up. Patients reported that oral health practitioners generally ask about tobacco use but do not provide interventions. Patients were open to discussing their tobacco use with practitioners and had favourable attitudes about NRTS.

CONCLUSIONS

This formative work suggests that NRTS and AAR may be feasible to implement in dental care settings. Future studies are needed to assess the effectiveness and implementation potential of NRTS in dental care settings.

Dietary patterns suggest that dark chocolate intake may have an inhibitory effect on oral cancer: a Mendelian randomization study

Background

Previous studies reported that variations in dietary intake patterns substantially impact human health, specifically tumorigenesis. However, confounding factors in previous cohort studies have obscured the relationship between dietary differences and the risk of oral cancer (OC).

Materials and methods

We developed an outcome dataset from genome-wide association studies (GWAS) data on three OCs within the GAME-ON project, using GWAS-META merging. We extracted 21 dietary exposures, including 10 dietary patterns, 6 vitamins, and 5 micronutrients, from the UK Biobank database, using the inverse variance weighting method as the primary statistical method. Sensitivity analysis was conducted to detect heterogeneity and pleiotropy. Serum metabolite concentrations were adjusted using multivariate Mendelian randomization.

Results

Of the 10 analyzed dietary patterns, 8 showed no significant association with the risk of developing OC. Consumption of dark chocolate (inverse variance weighted [IVW]: Odds ratio (OR) = 0.786, 95% confidence interval [CI]: 0.622-0.993, p = 0.044) and sweet pepper exhibited an inverse relationship with OC risk (IVW: OR = 0.757, 95% CI: 0.574-0.997, p = 0.048). Reverse MR analysis revealed no reverse causality. Furthermore, no significant correlation was observed between the intake of 6 vitamins and 5 micronutrients and the risk of developing OC. After using multivariable MR to adjust for serum caffeine, linoleate, theophylline, and theobromine metabolism levels, consuming dark chocolate was unrelated to a decreased risk of OC. After adjusting each serum metabolite individually, the observed p-values deviated from the original values to varying degrees, indicating that the components of dark chocolate could have different effects. Among these components, theophylline demonstrated the most significant inhibitory effect.

Conclusion

This study demonstrated a causal relationship between the intake of dark chocolate and sweet peppers and a lower risk of OC. The components of dark chocolate could have different effects.

The association between smoking and smokeless tobacco use with dental caries among Pakistani patients

BACKGROUND

Tobacco use is widely recognised as a significant risk factor for oral cancer and periodontal diseases. However, the relationship between various types of tobacco use and dental caries has been inconsistent. This study aimed to determine the association between smoking and smokeless tobacco and dental caries among patients in a tertiary care hospital in Quetta, Pakistan.

METHODS

This cross-sectional study was conducted from November 2020 to March 2021 among patients in a tertiary care hospital in Quetta, Pakistan. Oral examinations and interviews were performed according to the WHO Oral Health Survey basic methods (5th edition) to determine dental caries status, tobacco use, and oral health behaviours. The odds ratio and binary logistic regression were analysed to assess the association between the types (smoking tobacco, smokeless tobacco, and use of both types), duration, and frequency of tobacco use and high caries level (DMFT ≥ 5).

RESULTS

Four hundred participants aged 18-65 were included, and 67.8% were tobacco users. Use of both smoking and smokeless tobacco (aOR = 14.7, 95%CI = 1.87-115.96, p = 0.011), smokeless tobacco only (aOR = 5.90, 95%CI = 1.89-18.37, p = 0.002), and smoking only (aOR = 2.18, 95%CI = 1.23-3.88, p = 0.008) were associated with significantly increased risk of high caries. Using tobacco for longer periods and more frequently daily also significantly increases the risk of high caries.

CONCLUSION

Smoking and smokeless tobacco are significantly associated with high dental caries after adjusting for other factors. Due to the high severity of dental caries and the high prevalence of tobacco use among Pakistani patients in this study, it is highly recommended to strengthen policies aimed at reducing tobacco usage, including smokeless forms.

Clinical characteristics and caries risk assessment of tobacco heating systems smokers, cigarette smokers and non-smokers: a cross-sectional study

OBJECTIVES

The study compared clinical characteristics and caries risk assessments between tobacco heating system (THS) smokers, cigarette smokers and non-smokers.

MATERIALS AND METHODS

General data, data regarding fluoridation, smoking and dietary habits was obtained through a questionnaire. Caries experience was assessed by the DMFT index; the amount of biofilm by the Full mouth plaque score index; the amount of salivation by the quantum of stimulated salivation test; salivary pH with pH indicator strips and salivary number of S.mutans and Lactobacilli by cultivation on agar plates. The Cariogram method was used to assess caries risk.

RESULTS

No differences between the groups was detected regarding education level, average daily number of meals, fluoridation programs, systemic diseases, and caries experience. The groups significantly differed in the amount of salivary S.mutans and Lactobacilli (p < 0.001), accumulated biofilm (p = 0.034), salivation quantum (p < 0.001), and saliva pH (p = 0.009). Exposure to tobacco smoke and heated tobacco aerosol increased the accumulation of biofilm and decreased salivary pH. Smoking increased S. mutans, while THS consumption decreased salivation and Lactobacilli the most. The Cariogram analysis found no differences in chances of avoiding new caries lesions between the groups, but a significant difference in developing caries lesions due to dietary habits was detected (p < 0.001) with non-smokers having higher risk than smokers, but not than THS consumers.

CONCLUSIONS

THS and cigarette smoking were related to clinical characteristics that affect caries activity even though the caries risk assessment revealed no significant difference in the chances of avoiding new caries lesions between the groups.

CLINICAL RELEVANCE

THS and cigarette smokers could have higher caries activity than non-smokers. The clinical study protocol has been registered on ClinicalTrials.gov under the ID number: NCT06314100.

Novel prognostic nomograms for postoperative patients with oral cavity squamous cell carcinoma in the central region of China

BACKGROUND

Oral cavity squamous cell carcinoma (OCSCC) is the most common pathological type in oral tumors. This study intends to construct a novel prognostic nomogram model based on China populations for these resectable OCSCC patients, and then validate these nomograms.

METHODS

A total of 607 postoperative patients with OCSCC diagnosed between June 2012 and June 2018 were obtained from two tertiary medical institutions in Xinxiang and Zhengzhou. Then, 70% of all the cases were randomly assigned to the training group and the rest to the validation group. The endpoint time was defined as overall survival (OS) and disease-free survival (DFS). The nomograms for predicting the 3-, and 5-year OS and DFS in postoperative OCSCC patients were established based on the independent prognostic factors, which were identified by the univariate analysis and multivariate analysis. A series of indexes were utilized to assess the performance and net benefit of these two newly constructed nomograms. Finally, the discrimination capability of OS and DFS was compared between the new risk stratification and the American Joint Committee on Cancer (AJCC) stage by Kaplan-Meier curves.

RESULTS

607 postoperative patients with OCSCC were selected and randomly assigned to the training cohort (n = 425) and validation cohort (n = 182). The nomograms for predicting OS and DFS in postoperative OCSCC patients had been established based on the independent prognostic factors. Moreover, dynamic nomograms were also established for more convenient clinical application. The C-index for predicting OS and DFS were 0.691, 0.674 in the training group, and 0.722, 0.680 in the validation group, respectively. Besides, the calibration curve displayed good consistency between the predicted survival probability and actual observations. Finally, the excellent performance of these two nomograms was verified by the NRI, IDI, and DCA curves in comparison to the AJCC stage system.

CONCLUSION

The newly established and validated nomograms for predicting OS and DFS in postoperative patients with OCSCC perform well, which can be helpful for clinicians and contribute to clinical decision-making.

Serum cell division control 42 reflects treatment response and survival profiles in recurrent or metastatic oral squamous cell carcinoma patients who receive programmed death-1 inhibitors

OBJECTIVES

Cell division control 42 (CDC42) facilitates tumor growth, migration, and immune escape to accelerate the pathogenesis and progression of oral squamous cell carcinoma (OSCC). This study intended to explore the optimal cut-value of serum CDC42 for predicting treatment response to programmed death-1 (PD-1) inhibitors and survival in recurrent or metastatic (R/M) OSCC patients.

METHODS

CDC42 was detected from serum by enzyme-linked immunosorbent assay in 45 R/M OSCC patients before initiating PD-1 inhibitors with or without chemotherapy. Different cutoff values (500, 600, 700, and 800 pg/mL) of CDC42 were selected for further analyses.

RESULTS

The median (interquartile range) value of CDC42 was 604.0 (477.5-867.5) pg/mL in R/M OSCC patients. Generally, objective response rate (ORR) and disease control rate (DCR) were 37.8 % and 62.2 %. Additionally, ORR (P = 0.030) and DCR (P = 0.004) were decreased in patients with CDC42 ≥ 700 pg/mL versus those with CDC42 < 700 pg/mL; meanwhile, DCR was also reduced in patients with CDC42 ≥ 800 pg/mL versus those with CDC42 < 800 pg/mL (P = 0.014). Interestingly, CDC42 ≥ 600 (P = 0.023), 700 (P = 0.007), and 800 (P = 0.039) pg/mL were related to shorter progression-free survival (PFS). While only CDC42 ≥ 700 (P = 0.004) and 800 (P = 0.046) pg/mL were correlated with worse overall survival (OS). After adjustment, only CDC42 ≥ 700 pg/mL (yes vs. no) independently estimated poor PFS (hazard ratio (HR) = 2.637, P = 0.005) and OS (HR = 5.824, P < 0.001).

CONCLUSION

CDC42 ≥ 700 pg/mL exerts the optimal prognostic ability to reflect poor treatment response and survival profiles in R/M OSCC patients who receive PD-1 inhibitors.

A Combination of Curcumin and Lactobacillus rhamnosus GG Inhibits Viability and Induces Apoptosis in SCC-9 Human Oral Squamous Cell Carcinoma Cells

The aim of this study was to evaluate the effect of curcumin combined with Lactobacillus rhamnosus GG cell-free supernatant (LGG CFS) on the proliferation and induction of apoptosis in SCC-9 oral squamous cell carcinoma (OSCC) cells. Curcumin (40 µg/ml) and 25% v/v LGG CFS (108 CFU/ml), both alone and in a combination regimen, significantly decreased the viability of SCC-9 cells and normal human gingival fibroblast (HGF) cells. Interestingly, the combination of low doses of curcumin (5 µg/ml) and 25% v/v LGG CFS (106 CFU/ml) had no effect on the HGF cells but significantly inhibited the viability of SCC-9 cells (p < 0.05). Flow cytometric analysis revealed that SCC-9 cells treated with the combination of low-dose curcumin and low-dose LGG CFS had a higher apoptotic rate than the cells in the control group and the single treatment groups (p < 0.05). The combined treatment also significantly increased the Bax/Bcl2 mRNA and protein expression in SCC-9 cells (p < 0.05) but not in HGF cells, indicating the underlying mechanism of the combination regimen. There was no significant difference in caspase-3 protein expression or the Bcl-xL/Bak and Mcl-1/Bak ratios between the treatment and control groups in both cell lines. These findings suggested that the coadministration of curcumin and LGG could exhibit anticancer effects in SCC-9 cells without causing toxicity to normal fibroblast cells.

Mechanisms and Potential Clinical Implications of Oral Microbiome in Oral Squamous Cell Carcinoma

Microorganisms in the oral cavity are abundant in the human body. At present, more than 700 species of oral microorganisms have been identified. Recently, a lot of literature has indicated that the oral microbiota plays an important role in the occurrence, development, and prognosis of oral squamous cell carcinoma (OSCC) through various mechanisms. And researchers are now trying to utilize oral microbiota in cancer diagnosis and treatment. However, few articles systematically summarize the effects of oral microbes in the diagnosis, treatment, and disease outcomes of oral cancer. Herein, we made a summary of the microbial changes at cancerous sites and placed more emphasis on the mechanisms by which the oral microbiome promotes cancerization. Moreover, we aimed to find out the clinical value of the oral microbiome in OSCC.

Impacts of smoking on oral health-what is the role of the dental team in smoking cessation?

DATA SOURCES

Electronic searches were conducted on databases (PubMed, EMBASE, and Google Scholar). In addition, websites of national organisations (US Food and Drug Administration, National Cancer Institute, Centres for Disease Control and Prevention, American Dental Association, Office of Disease Prevention and Health Promotion, National Institute on Drug Abuse, Agency for Healthcare Research and Quality) were also searched.

STUDY SELECTION

To achieve the objectives of the study, systematic reviews, controlled clinical trials, and observational studies published between October 2021 and February 2022 were considered.

DATA EXTRACTION AND SYNTHESIS

This narrative review included articles which investigated the role of Dentistry professionals and their impact on smoking cessation and the effects resulting from tobacco use on oral health.

RESULTS

The review revealed that smokers have a significantly higher likelihood of developing oral cancer (95% CI: 3.19-6.77) compared to non-smokers. Passive smokers also have an increased risk (1.51 times) of developing oral cancer (95% CI: 1.20-1.91). Additionally, smokers have an 80% increased risk of periodontitis (RR = 1.82; 95% CI: 1.43-2.31), an 85% worsened periodontal condition (RR = 1.85; 95% CI: 1.5-2.2), and a 36.6% increase in caries prevalence (OR = 1.84; 95% CI: 1.64-2.07). Smoking is also associated with a higher potential for dental implant failure in a dose-dependent manner. Brief educational interventions by the dental team resulted in a smoking cessation rate of 74/1000 individuals versus 27/1000 individuals in the control group. When combined with pharmacological therapy, these interventions may lead to an additional 50 to 70% increase in long-term smoking abstinence.

CONCLUSIONS

Smoking is strongly linked to an increased risk of oral cancer, dental caries, implant failure, and periodontal disease. Dental teams play a vital role in identifying and addressing oral pathologies related to smoking and providing necessary care for smoking cessation. Brief educational interventions, either alone or in combination with pharmacotherapy, offer valuable approaches for the dental team to support smoking cessation. However, establishing a comprehensive training and continuing education program is crucial to integrate dental professionals into a multidisciplinary smoking cessation program.

KRAS mutations upregulate Runx1 to promote occurrence of head and neck squamous cell carcinoma

Gene mutations play an important role in head and neck squamous cell carcinoma (HNSCC) by not only promoting the occurrence and progression of HNSCC but also affecting sensitivity to treatment and prognosis. KRAS is one of the most frequently mutated oncogenes, which has been reported to have a mutation rate from 1.7% to 12.7% and may lead to poor prognosis in HNSCC, but its role remains unclear. Here, we found that the KRAS mutation can promote HNSCC generation through synergism with 4-Nitroquinoline-1-Oxide(4NQO). Mechanistically, KRAS mutations can significantly upregulate Runx1 to promote oral epithelial cell proliferation and migration and inhibit apoptosis. Runx1 inhibitor Ro 5-3335 can effectively inhibit KRAS-mutated HNSCC progression both in vitro and in vivo. These findings suggest that the KRAS mutation plays an important role in HNSCC and that Runx1 may be a novel therapeutic target for KRAS-mutated HNSCC.

Mutant p53 in head and neck squamous cell carcinoma: Molecular mechanism of gain‑of‑function and targeting therapy (Review)

Head and neck squamous cell carcinoma (HNSCC) is one of the most widespread malignancies worldwide. p53, as a transcription factor, can play its role in tumor suppression by activating the expression of numerous target genes. However, p53 is one of the most commonly mutated genes, which frequently harbors missense mutations. These missense mutations are nucleotide substitutions that result in the substitution of an amino acid in the DNA binding domain. Most p53 mutations in HNSCC are missense mutations and the mutation rate of p53 reaches 65‑85%. p53 mutation not only inhibits the tumor suppressive function of p53 but also provides novel functions to facilitate tumor recurrence, called gain‑of‑function (GOF). The present study focused on the prevalence and clinical relevance of p53 mutations in HNSCC, and further described how mutant p53 accumulates. Moreover, mutant p53 in HNSCC can interact with proteins, RNA, and exosomes to exert effects on proliferation, migration, invasion, immunosuppression, and metabolism. Finally, several treatment strategies have been proposed to abolish the tumor‑promoting function of mutant p53; these strategies include reactivation of mutant p53 into wild‑type p53, induction of mutant p53 degradation, enhancement of the synthetic lethality of mutant p53, and treatment with immunotherapy. Due to the high frequency of p53 mutations in HNSCC, a further understanding of the mechanism of mutant p53 may provide potential applications for targeted therapy in patients with HNSCC.

The potential roles of cigarette smoke-induced extracellular vesicles in oral leukoplakia

BACKGROUND

The onset of oral leukoplakia (OLK), the most common oral lesion with a high risk of malignant transformation, is closely associated with the exposure of cigarette smoke. Cigarette smoke is a complicated mixture of more than 4500 different chemicals including various oxidants and free radical, which contributes to the onset of immune and inflammatory response or even carcinogenesis. Recent studies have proved that the exposure of cigarette smoke leads to the onset and aggravation of many diseases via significantly changed the production and components of extracellular vesicles. The extracellular vesicles are membrane-enclosed nanosized particles secreted by diverse cells and involved in cell-cell communication because of their ability to deliver a number of bioactive molecules including proteins, lipids, DNAs and RNAs. Getting insight into the mechanisms of extracellular vesicles in regulating OLK upon cigarette smoke stimulation contributes to unravel the pathophysiology of OLK in-depth. However, evidence done on the role of extracellular vesicles in cigarette smoke-induced OLK is still in its infancy.

MATERIALS AND METHODS

Relevant literatures on cigarette smoke, oral leukoplakia and extracellular vesicles were searched in PubMed database.

CONCLUSIONS

In this review, we summarize the recent findings about the function of extracellular vesicles in the pathogenesis of cigarette smoke-induced diseases, and to infer their potential utilizations as diagnostic biomarkers, prognostic evaluation, and therapeutic targets of OLK in the future.

Oral-malodor measurement and intention to quit smoking in men: A before-after study

INTRODUCTION

Few studies have examined the effect of feedback based on oral-malodor measurements on the motivation to quit smoking. Therefore, this study examined whether oral-malodor measurements were associated with the intention to quit smoking.

METHODS

This retrospective, uncontrolled before-after study invited smokers to a workplace health event in 2019 and 2020 to motivate them to quit smoking. They attended seminars on oral health and smoking cessation aids, and then underwent respiratory function and oral-malodor measurements using exhaled and oral cavity air, respectively. Intention to quit smoking was evaluated by answers to questions regarding the intention to quit in the next 1 or 6 months in questionnaires collected before and after the event. This study analyzed 241 men aged 20-54 years (mean: 33.2 ± 10.5) to examine factors associated with the intention to quit in multivariable logistic regression analyses for age, tobacco type (cigarettes and heated-tobacco products), and category of tobacco consumption.

RESULTS

Before the event, 8.7%, 17.0%, and 74.3% of smokers had intended to quit in the next month, the next six months, or had no intention to quit, respectively. After the event, the respective percentages were 17.8%, 26.6%, and 55.6%. A higher methyl mercaptan concentration, a volatile sulfide component of oral malodor, was significantly associated with the intention to quit in the next month (adjusted odds ratio, AOR=4.24; 95% CI: 1.52-11.8, p=0.006). The participants with higher daily tobacco consumption were less likely to acquire the intention to quit in the next six months (AOR=0.37; 95% CI: 0.15-0.92, p=0.032). Other variables, such as lung age deficit, exhaled CO concentration, and hydrogen sulfide concentration (another component of oral malodor), were not significantly associated.

CONCLUSIONS

Oral-malodor measurement feedback may help motivate men to quit smoking in the next 1 month rather than in the next six months.

The Effect of Terra-Cortril as Local Pain Medication on the Healing Process of a Fresh Extraction Socket: A Retrospective Cohort Study

(1) Background: Use of Terra-Cortril may reduce pain and discomfort after tooth extraction. It is widely used among dentists, especially for third molar extraction and for treatment of dry socket. Only few case reports described unsuccessful healing with formation of myospherulosis. (2) Aim: The primary objective of this retrospective cohort study was to compare the occurrence of unsuccessful healing between extraction sockets locally treated with Terra-Cortril (TC) (exposure cohort) and extraction sockets subjected to unassisted healing (non-exposure cohort). The assessment of the three-dimensional morphology of the bone was a secondary objective. (3) Material and methods: The records of patients who had one or more extractions between 1 January 2020 and 1 July 2021 followed by implant placement in one private practice were retrieved and data were extracted. At the time of implant placement, practitioners established, both clinically and radiographically, if the healing was successful or unsuccessful. Explanatory demographic as well as clinical variables were extracted from patient files, checked and supplemented by contacting patients in cases of missing data. (4) Results: 69 patients were included who had, in total, 99 extractions. The exposure cohort included 55 sites, while the non-exposure cohort included 44 sites. A total of 56 sites demonstrated successful healing, and 53 showed unsuccessful healing. The regression model identified TC as a significant predictor (p = 0.014) for unsuccessful healing with an odds ratio of 2.86. Sites treated with Terra-Cortril had a significantly greater bone defect at level -1 mm, level -3 mm, and level -5 mm from the bone crest, and significantly greater maximal vertical and horizontal bone defects. At sites where Terra-Cortril was used, significantly more surgical consequences were reported (70.91% vs. 18.18%, p < 0.001). (5) Conclusions: fresh extraction sockets treated with Terra-Cortril increased the likelihood of unsuccessful healing with an odds ratio of 2.86. The greater defect size leads to significantly more limitations when planning implants at sites previously treated with TC.

CDH4 inhibits ferroptosis in oral squamous cell carcinoma cells

BACKGROUND

The cadherin-4 gene (CDH4), a member of the cadherin family genes, encodes R-cadherin (R-cad); however, the function of this gene in different types of cancer remains controversial. The function of CDH4 in OSCC (oral squamous cell carcinoma) is unknown.

MATERIALS AND METHODS

We use the Cancer Genome Atlas (TCGA) database to find the expression of CDH4 in OSCC is more than normal tissue. Our tissue samples also confirmed that CDH4 gene was highly expressed in OSCC. The related cell function assay detected that CDH4 promotes the ability of cell proliferation, migration, self-renewal and invasion. Cell staining experiment confirmed that the change of CDH4 expression would change the cell mortality. The western blot of GPX4 (glutathione-dependent peroxidase-4), GSH (reduced glutathione) test assay and MDA(Malondialdehyde) test assay show that the expression of CDH4 may resist the sensitivity of ferropotosis in OSCC.

RESULTS

CDH4 was upregulated in OSCC samples and was correlation with poor survival of patients. High expression of CDH4 effectively promotes the proliferation, mobility of OSCC cells and reduce the sensitivity of OSCC cells to ferroptosis. CDH4 is positively correlated with EMT pathway genes, negatively correlated with fatty acid metabolism pathway genes and peroxisome pathway genes, and positively correlated with ferroptosis suppressor genes in OSCC.

CONCLUSIONS

These results indicate that CDH4 may play a positive role in tumor progression and resistance ferroptosis and may be a potential therapeutic target for OSCC.

Transcriptome characterization of human gingival mesenchymal and periodontal ligament stem cells in response to electronic-cigarettes

The potential toxicities and threats of electronic cigarettes (E-cigs) on periodontal health remain elusive. Gingival mesenchymal stem cells (GMSCs) and periodontal ligament stem cells (PDLSCs) contribute to cell differentiation and regeneration for periodontium as well as inflammatory modulation. However, the effects of E-cig exposure on periodontal tissues, particularly GMSCs and PDLSCs, and the underlying epigenetic mechanisms remain largely unknown. In this study, we conducted RNA-seq analysis to examine the transcriptome of human GMSCs and PDLSCs exposed to four types of E-cigs (aerosol and liquid with tobacco and menthol flavor) and conventional tobacco smoke in vitro. Our results showed that E-cig exposure primarily impacted the immunoregulation and inflammatory responses to pathogenic microorganisms in GMSCs, and the microenvironment, differentiation and response to corticosteroid in PDLSCs, which were significantly different from the damage effects caused by tobacco smoke. Additionally, we discovered a large number of differentially expressed non-coding RNAs among the different E-cig exposure methods and flavors. We also noticed that in GMSCs, CXCL2 was especially down-regulated by E-cig aerosol exposure whereas up-regulated by E-liquid exposure compared to control. Of note, the enhancer elements near CXCL2 and other genes located at Chromosome 4 contributed to the transcription activity of these genes, and KDM6B was remarkably elevated in response to E-liquid exposure. Lastly, we conducted ChIP-seq analysis to confirm that the elevated gene transcription by E-liquids was due to the weakened H3K27me3 at genome-wide enhancer elements in GMSCs, but not at promoter regions. Taken together, our results characterized the diverse gene expression profiles of GMSCs and PDLSCs in response to E-cigs with different exposure methods and flavors in vitro, and indicated a novel mechanism of KDM6B-mediated H3K27me3 on enhancers for gene transcription regulation. Our data could be served as a resource for emphasizing the understanding of E-cigs in periodontal health.

Lip and Oral Cavity Cancer Incidence and Mortality Rates Associated with Smoking and Chewing Tobacco Use and the Human Development Index in 172 Countries Worldwide: An Ecological Study 2019-2020

Tobacco use is associated with diseases worldwide, including cancer. This is one of the major public health problems globally, causing more than 19 million new cases in 2020. Lip and oral cavity cancer (LOCC) is neoplastic growth in the tongue, gums, and lips. The objective of this ecological study was to quantify the strength of the association between incidence and mortality of LOCC, with tobacco use and with the Human Development Index (HDI). Incidence and mortality data on LOCC were obtained for 172 countries in 2020, from the Global Cancer Observatory (GLOBOCAN). The prevalence of tobacco smoking and chewing was obtained from reports conducted in 2019. The inequality in human development was estimated using the HDI from the United Nations Development Program, Human Development Report (2019). Statistically significant correlations were observed between the incidence of LOCC and tobacco smoking and chewing prevalence, except for negative correlations between the prevalence of tobacco smoking LOCC mortality in women, just as in the case of the HDI. No statistically significant differences were found between the prevalence of tobacco chewing only and the incidence of LOCC overall and by sex. A higher LOCC incidence overall and by sex was associated with higher HDI. In conclusion, the present study found positive correlations for various HDI socioeconomic indicators and tobacco use with the incidence and mortality of LOCC, but also a few inverse correlations.

The prognostic role and metabolic function of GGPS1 in oral squamous cell carcinoma

Background: GGPS1(geranylgeranyl diphosphate synthase 1) is a member of the prenyltransferase family. Abnormal expression of GGPS1 can disrupt the balance between protein farnesylation and geranylgeranylation, thereby affecting a variety of cellular physiologic and pathological processes. However, it is still unknown how this gene could contribute to the prognosis of oral squamous cell carcinoma (OSCC). This study aimed to explore the prognostic role of GGPS1 in OSCC and its relationship with clinical features. Methods: The RNA-seq data and clinical data were obtained from TCGA. The survival analyses, Cox regression analyses, ROC curves, nomograms, calibration curves, and gene function enrichments were established by R software. Results: The results showed that the high expression of GGPS1 in OSCC is related to poor prognosis. At the same time, multivariate Cox regression analyses showed that GGPS1 could be an independent prognostic biomarker, and its gene expression level is closely related to the histological stage of cancer. GGPS1 may promote tumorigenesis because of its metabolic function. Conclusion: This study came to a conclusion that GGPS1, whose high expression has a significantly unfavorable meaning toward the prognosis of OSCC, can act as a novel independent biomarker for OSCC.

Downregulation of zinc finger protein 71 expression in oral squamous cell carcinoma tissues and its underlying molecular mechanism

BACKGROUND

Patients with oral squamous cell carcinoma (OSCC) have poor prognoses due to a limited understanding of the pathogenesis of OSCC. Zinc finger protein (ZNF) is the largest transcription factor family in the human genome and exert diverse and important functions. Nevertheless, the exact expression status and molecular mechanism of ZNF71 have not been described in OSCC. Therefore, this study aimed to identify the specific expression level of ZNF71 in OSCC tissues and to further interpret the potential molecular mechanism of ZNF71 in the pathogenesis of OSCC.

METHODS

In-house immunohistochemical staining of 116 OSCC samples and 29 non-OSCC samples was employed to detect the expression status of ZNF71 at the protein level of OSCC tissues. Single-cell RNA sequencing data from 7 OSCC samples was used to explore the expression landscape of ZNF71 in different cell types from OSCC tissues. High-throughput RNA sequencing data and gene chips data from 893 OSCC samples and 301 non-OSCC samples were utilized to identify the specific expression level of ZNF71 at the bulk mRNA level of OSCC tissues. Here, standardized mean difference (SMD) value was applied to calculate the expression differences between OSCC group and non-OSCC group. Multiple datasets were included; hence, the results were considered to be more reliable. Sensitivity analysis was conducted to evaluate the stability of the results. Enrichment analysis and immune infiltration analysis were used to explore the underlying molecular mechanism of ZNF71 in OSCC.

RESULTS

ZNF71 was significantly downregulated in OSCC tissues at the protein level (SMD = -1.96, 95 % confidence interval [95 % CI]: -2.43 to -1.50). ZNF71 was absent in various cell types from OSCC tissues including cancerous epithelial cells and tumor-infiltrating immune cells. ZNF71 was downregulated in OSCC tissues at the bulk mRNA level (SMD = -0.38, 95 % CI: -0.75 to -0.02). Enrichment analysis showed that positively and differentially co-expressed genes mainly concentrated on "herpes simplex virus 1 infection" and "regulation of plasma membrane bounded cell projection organization", and negatively and differentially co-expressed genes mainly participated in "cell cycle" and "DNA metabolic process". Moreover, the putative target genes of ZNF71 mainly participated in "cellular respiration" and "protein catabolic process". Finally, immune infiltration analysis revealed that ZNF71 expression was positively correlated with multiple immune cells including activated B cells, memory B cells, and natural killer (NK) cells, and negatively correlated with various immune cells, including CD56 bright NK cells, neutrophil, and immature dendritic cells.

CONCLUSION

The downregulation of ZNF71 may influence the initiation and promotion of OSCC by reducing immune infiltration, accelerating cell cycle progression, and affecting metabolic process, and this requires further research.

Comparison between three age-stratified cohorts reveals poor prognosis of young patients with tongue carcinoma

Objectives

Investigation of the prognosis of young patients with tongue carcinoma has been the focus of several recent studies aimed at improving future precision treatment. Most studies have been two-cohort investigations comparing young and older patients, who have wide discrepancies in prognosis. Older patients, especially those aged >70 years, often have a poor general condition. This affects the prognosis of the older cohort and accounts for the discrepancies observed in two-cohort studies. Accordingly, in this study, older patients (aged ≥71 years) were separated and compared to young and middle-aged patients.

Methods

A total of 257 patients with oral tongue carcinoma referred during 2011–2017 were analyzed. Patients were sorted into young (aged ≤40 years), middle-aged (aged ≥41 and ≤70 years), and older (aged ≥71 years) groups. Overall survival (OS) and disease-free survival (DFS) were compared among the groups. Furthermore, patterns of recurrence rates were compared.

Results

Compared with young patients, there was no difference in OS or DFS for older patients (hazard ratio [HR]: 1.2, 95% confidence interval [CI]: 0.5–2.7 and HR: 0.7, 95% CI: 0.4–1.2, respectively) in a multivariate analysis. There was also no difference in OS (HR: 0.6, 95% CI: 0.3–1.3) for middle-aged patients. However, middle-aged patients had low recurrence rates (HR: 0.5, 95% CI: 0.3–0.8). With respect to the recurrence type, middle-aged patients had a low local recurrence rate (HR: 0.3, 95% CI: 0.1–0.7).

Conclusion

Three-cohort studies should be conducted to evaluate whether the prognosis of young patients with tongue carcinoma is truly poor in terms of future precision treatment.

Oral Health Service Access in Racial/Ethnic Minority Neighborhoods: A Geospatial Analysis in Washington, DC, USA

Previous studies on individual-level variables have improved our knowledge base of oral health service use. However, environmental or contextual variables are also important in understanding oral health disparities in racial and ethnic neighborhoods. Based on Bronfenbrenner’s ecological framework, this study examines the geographic availability of oral health providers in Washing-ton DC, U.S.A. Census tract-level data were drawn from the American Community Survey, joined with tract-level shapefiles, and overlaid with the geographic location of dental services throughout the city. Visual maps, descriptive statistics, and spatial lag regression models showed that census tracts with higher concentrations of African Americans were significantly farther from their nearest oral health providers (r = 0.19, p < 0.001), after controlling for neighborhood poverty rate, median age, and gender. Such findings confirm that in urban areas with highly di-verse populations such as Washington DC, racial disparities in oral health care access are signifi-cant. The study highlights that identifying neighborhoods with limited oral health care providers should be a priority in diminishing racial disparities in oral health service access. Improving access to racial/ethnic minority communities, especially African American neighborhoods, will require changes in health policies and programs, workforce development, resource allocation, community outreach, and educational programs.

Oral Osteomicrobiology: The Role of Oral Microbiota in Alveolar Bone Homeostasis

Osteomicrobiology is a new research field in which the aim is to explore the role of microbiota in bone homeostasis. The alveolar bone is that part of the maxilla and mandible that supports the teeth. It is now evident that naturally occurring alveolar bone loss is considerably stunted in germ-free mice compared with specific-pathogen-free mice. Recently, the roles of oral microbiota in modulating host defense systems and alveolar bone homeostasis have attracted increasing attention. Moreover, the mechanistic understanding of oral microbiota in mediating alveolar bone remodeling processes is undergoing rapid progress due to the advancement in technology. In this review, to provide insight into the role of oral microbiota in alveolar bone homeostasis, we introduced the term “oral osteomicrobiology.” We discussed regulation of alveolar bone development and bone loss by oral microbiota under physiological and pathological conditions. We also focused on the signaling pathways involved in oral osteomicrobiology and discussed the bridging role of osteoimmunity and influencing factors in this process. Finally, the critical techniques for osteomicrobiological investigations were introduced.

Impact of Oral Hygiene on Prognosis in Patients With Squamous Cell Carcinoma of the Lower Gingiva

Objective: We aimed to analyze the significance of oral hygiene in patients with squamous cell carcinoma of the lower gingiva.

Methods: Oral hygiene was assessed using a questionnaire by calculating the oral health (OH) score and the dental care (DC) score. The association of oral hygiene with clinical pathologic variables, disease free survival (DFS), and overall survival (OS) was analyzed.

Results: Four out of 53 non-smokers and 19 out of 90 current or former smokers had an OH score of 6 (statistically significant difference, p = 0.036). Fifteen out of 63 patients with a T3/T4 tumor and 8 out of 80 patients with a T1/T2 tumor had an OH score of 6 (statistically significant difference, p = 0.026). Similar statistically significant findings were noted with respect to the DC scores, smoking status, and tumor stage. Among patients with an OH score of 0–5, the 5-year DFS and OS rates were 55 and 50%, respectively, and among patients with an OH score >5, they were 46 and 43%, respectively (both differences statistically significant, p < 0.05). Among patients with a DC score of 0–2, the 5-year DFS and OS rates were 69 and 51%, respectively and among patients with a DC score >2, they were 50 and 47%, respectively (both differences statistically significant, p < 0.05). Cox model confirmed OH and DC scores as independent factors affecting the DFS and OS.

Conclusion: Poor oral hygiene was associated with decreased DFS and OS.