Characterization of Chronic Mechanical Irritation in Oral Cancer

Differences among oral carcinomas arising de novo from those associated with oral potentially malignant disorders: a systematic review and meta-analysis

OBJECTIVE

To analyze the frequency of sequential oral squamous cell carcinomas (s-OSCC), preceded by oral potentially malignant disorders, and OSCC de novo (OSCC-dn) and explore differences in their clinicopathologic presentations.

STUDY DESIGN

A structured electronic search strategy identified studies that analyzed frequency, clinical, biological, demographic, biomarkers, and prognostic features of s-OSCC and OSCC-dn according to PRISMA guidelines in PubMed, Scopus, Cochrane Library, and Google Scholar, up to January 31, 2023. Inclusion criteria were original English, Spanish, Portuguese, French, Italian, and German cross-sectional, cohort, and case-control studies. The quality of studies was assessed using the Agency for Research and Health Quality tool and the Newcastle-Ottawa Scale tool.

RESULTS

The final selection included 40 studies. OSCC-dn and s-OSCC represent, respectively, 71% and 29% of cases of OSCC (P = .00), showing a higher percentage of T1 or of T1+T2 in s-OSCC (P < .0001). The association meta-analysis showed OSCC-dn with a significant association. The meta-analysis showed that s-OSCC was significantly associated with smaller tumor size, absence of distant metastases, relapses, male sex, and tumor sites different from tongue; and OSCC-dn was associated with more advanced tumor size, more regional and distant metastases, more advanced stages, and worse survival.

CONCLUSIONS

S-OSCC was less frequent than expected. OSCC-dn seems to have specific clinical, biological, and prognostic features. Future perspectives on oral cancer prevention should address novel approaches and alternatives to screening, such as urgent referral of OSCC-dn.

Association between age, gender, and oral traumatic ulcerative lesions: a retrospective study

BACKGROUND

Oral traumatic ulcerative lesions (OTUL) are commonly encountered in clinical practice, yet there is limited research on their clinical characteristics and traumatic etiological factors. This retrospective study aimed to analyze the age, gender, clinical characteristics, and traumatic etiological factors in a large cohort of patients with OTUL and provide valuable insights for dental clinicians to optimize patient care and prevention strategies.

METHODS

A total of 1543 patients with OTUL were enrolled in this study. Age, gender, medical history, clinical characteristics and traumatic etiological factors were collected and analyzed. Logistic regression analysis was performed to determine the significance of age and gender as factors related to OTUL.

RESULTS

The study revealed significant variations in clinical characteristics and traumatic etiological factors among different age groups and between genders. Logistic regression analysis demonstrated that both age and gender were significant factors related to OTUL.

CONCLUSION

The clinical characteristics of OTUL and traumatic etiological factors appear to be significantly different according to age and gender. More targeted prevention strategies should be implemented for all age and gender groups.

A Retrospective Analysis of the Clinicopathological Profile of Oral Squamous Cell Carcinoma in Tobacco and Non-tobacco Users: Highlighting the Significance of Chronic Mechanical Irritation

BACKGROUND AND AIM

Oral squamous cell carcinoma (OSCC) is among the leading top three cancers in India. However, recent literature has shown an increase in the rise of oral cancer in younger individuals without any history of tobacco-related habits. Chronic mucosal irritation (CMI) has been noted to have a substantial impact on the development and etiology of OSCC. With the shift in the trend, it is imperative to observe and monitor alterations associated with its etiological factors. The study aims to evaluate the prevalence and clinical characteristics of OSCC patients and the association of these parameters in cases with and without tobacco usage.

METHODOLOGY

A retrospective study spanning a period of 10 years was done on histopathologically diagnosed cases of OSCC. Various clinicopathological characteristics were collected from patient records, including demographic features, tobacco-related habits, including tobacco chewing and smoking, clinical presentation, anatomic sites, and histopathological grading based on the inclusion and exclusion criteria. The data were tabulated to Microsoft Excel (Microsoft Corporation, Redmond, WA), and descriptive statistics analysis and chi-square test of significance were applied to the data using IBM SPSS Statistics (version 29.0.2; IBM Corp., Armonk, NY). The study correlated the epidemiologic behavior of OSCC with age, gender, site, and tobacco-related habits.

RESULTS

This study included a sample size of 204 (72 females & 132 males). Tobacco-related habit-associated cases were 98 (48.5%) and without tobacco habits were 61 cases (29.6%). Etiology associated with CMI emerged to be a significant tooth-related factor. Out of 72 females, 32 (44.4%) of the females were without habit. OSCC caused by trauma from CMI was analyzed in 40 cases (19.6%) and 22 (55%) were females. The majority of lesions (76 (37.4%) cases) presented on the lateral border of the tongue. Among the OSCC patients with a history of chronic mechanical irritation, 37 (48.7%) cases were observed to be specifically on the lateral border of the tongue.

CONCLUSION

These 10-year data will generate awareness about the disease pattern occurring within a community and provide an overview of the prerequisite of considering CMI as an etiological factor for the development of OSCC without the association of tobacco-related habits.

A Tissue Engineered 3D Model of Cancer Cell Invasion for Human Head and Neck Squamous-Cell Carcinoma

Head and neck squamous-cell carcinoma (HNSCC) is associated with aggressive local invasiveness, being a main reason for its poor prognosis. The exact mechanisms underlying the strong invasive abilities of HNSCC remain to be elucidated. Therefore, there is a need for in vitro models to study the interplay between cancer cells and normal adjacent tissue at the invasive tumor front. To generate oral mucosa tissue models (OMM), primary keratinocytes and fibroblasts from human oral mucosa were isolated and seeded onto a biological scaffold derived from porcine small intestinal submucosa with preserved mucosa. Thereafter, we tested different methods (single tumor cells, tumor cell spots, spheroids) to integrate the human cancer cell line FaDu to generate an invasive three-dimensional model of HNSCC. All models were subjected to morphological analysis by histology and immunohistochemistry. We successfully built OMM tissue models with high in vivo-in vitro correlation. The integration of FaDu cell spots and spheroids into the OMM failed. However, with the integration of single FaDu cells into the OMM, invasive tumor cell clusters developed. Between segments of regular epithelial differentiation of the OMM, these clusters showed a basal membrane penetration and lamina propria infiltration. Primary human fibroblasts and keratinocytes seeded onto a porcine carrier structure are suitable to build an OMM. The HNSCC model with integrated FaDu cells could enable subsequent investigations into cancer cell invasiveness.

Bioactive Components of Areca Nut: An Overview of Their Positive Impacts Targeting Different Organs

Areca catechu L. is a widely cultivated tropical crop in Southeast Asia, and its fruit, areca nut, has been consumed as a traditional Chinese medicinal material for more than 10,000 years, although it has recently attracted widespread attention due to potential hazards. Areca nut holds a significant position in traditional medicine in many areas and ranks first among the four southern medicines in China. Numerous bioactive compounds have been identified in areca nuts, including alkaloids, polyphenols, polysaccharides, and fatty acids, which exhibit diverse bioactive functions, such as anti-bacterial, deworming, anti-viral, anti-oxidant, anti-inflammatory, and anti-tumor effects. Furthermore, they also display beneficial impacts targeting the nervous, digestive, and endocrine systems. This review summarizes the pharmacological functions and underlying mechanisms of the bioactive ingredients in areca nut. This helps to ascertain the beneficial components of areca nut, discover its medicinal potential, and guide the utilization of the areca nut.

Epidemiology and incidence of oral squamous cell carcinoma in the Iraqi population over 5 years (2014-2018)

Background

Oral squamous cell carcinoma is one of the most common and life-threatening neoplasms worldwide, and is responsible for approximately 90% of all oral malignancies.

Aim

This study was aimed at providing updated information on oral squamous cell carcinoma in all Iraqi governorates for the 5-year period from 2014 to 2018, including the annual incidence and demographic variables.

Materials and Methods

The total number of oral squamous cell carcinoma cases in Iraq, along with associated demographic information (age, sex, and site), for the 5-year period from 2014 to 2018 was obtained. The statistical analysis consisted of descriptive analysis, including frequency, percentage, and mean ± standard deviation. A χ ² test was performed to compare frequencies between male and female patients, among age groups, and among different OSCC sites. The χ ² test was also used to assess the association of each OSCC site with age and sex. The significance threshold was set at p < 0.05, and the confidence interval was set at 95%. The incidence rate of oral squamous cell carcinoma for each year was calculated by dividing the number of OSCC cases per year by the population of Iraq, then multiplying the result by 100,000.

Results

A total of 722 cases were recorded. Statistically, oral squamous cell carcinoma was found to be more prevalent in males and individuals over 40 years of age. The tongue was the most common site of occurrence. Lip squamous cell carcinoma cases were high in males. The incidence rate of oral squamous cell carcinoma was estimated to be 0.4 per 100,000 people.

Conclusion

Males and older people are at relatively higher risk of developing oral cancer. The tongue is the most affected site, but any site in the oral cavity may be involved. Further exploration of the causes of oral malignancy in Iraq is necessary to improve prevention strategies.

Oral squamous cell carcinoma arising from chronic traumatic ulcers

BACKGROUND

A proportion of oral squamous cell carcinoma (OSCC) is preceded by oral potentially malignant disorders (OPMD), and the rest might not be associated with any well-established OPMD. Chronic traumatic ulcer (CTU) has been suggested as a lesion with potential for malignant transformation, but the evidence is inconclusive.

OBJECTIVE

The aim of this study was to describe clinicopathological features of non-healing CTU (NHCTU) that later developed to OSCC.

MATERIALS AND METHODS

A retrospective cohort study was performed of patients attending the Facultad de Odontología Universidad Nacional de Córdoba (2013-2019). The study included patients with a provisional diagnosis of CTU. CTUs without complete healing after removal of traumatic factors-non healing CTU (NHCTU)-were investigated by biopsy. A detailed description of cases where a malignancy was diagnosed is presented.

RESULTS

A total of 107 CTU were included. Of these, 32 CTUs were considered NHCTU and two cases showed histological features of OSCC in the background of NHCTU. In both cases, lesions were found on the lateral tongue. Both were non smoking, non alcohol drinking individuals. Absence of any well-known OPMD was also registered.

CONCLUSIONS

The possibility of malignant transformation in a subset of tongue NHCTU should not be underestimated.

CLINICAL RELEVANCE

In a subgroup of patients, NHCTU could be considered an OPMD. Although the potential malignant transformation rate is low, these conditions should be always followed up.

Chronic mechanical trauma/irritation and oral carcinoma: A systematic review showing low evidence to support an association

BACKGROUND

Chronic trauma of oral mucosa, resulting from repeated and persistent mechanical irritative action of an intraoral injury agent, has repeatedly been reported to be possibly implicated in the development of oral squamous cell carcinoma (OSCC).

OBJECTIVES

The present systematic review aimed to assess whether chronic mechanical trauma can be considered a risk factor for OSCC.

DATA SOURCES

PubMed, CENTRAL (Cochrane Central Register of Controlled Trials), Scopus; EMBASE, Web of Science.

STUDY ELIGIBILITY CRITERIA

Cohort studies comparing OSCC incidence among subjects with/without chronic mechanical trauma or case-control or cross-sectional studies comparing chronic mechanical trauma among subjects with/without OSCC.

RESULTS

Only one prospective case-control study fulfilled the inclusion criteria, but the quality of the evidence provided is not enough to define trauma as a risk factor for OSCC. The main limitation is the presence of only one case-control study at high risk of bias. In the absence of strong evidence supporting the role of trauma in OSCC, a thorough discussion on trauma and carcinogenesis has been performed.

CONCLUSIONS

Available evidence does not support an active role for chronic trauma in oral carcinogenesis, neither as promoter nor as progressor factor. Prospective cohort studies able to better assess trauma in OSCC are needed.

Knowledge and Awareness of Oral Mucosal Diseases Among Saudi Dentists

Background:

Oral mucocutaneous lesions have a significant impact on patient care. Late diagnosis of oral lesions may affect patients' quality of life and prognosis. Dentists are usually the first to encounter such lesions, and many studies have explored the knowledge and management related to oral cancer. However, not many studies have examined a more comprehensive understanding and management of oral lesions, including infectious and autoimmune/immune-mediated diseases.

Aims:

This study aimed at evaluating dentists’ knowledge and referral patterns regarding oral mucocutaneous diseases.

Methods:

A questionnaire-based cross-sectional study was conducted to evaluate dentists’ knowledge about oral mucocutaneous diseases and referral patterns among Saudi dentists. A total of 301 participants were included in the study. It was voluntary and written informed consent was obtained from the participants. A Chi-square test was used to compare the categorical variables. A p-value of less than 0.05 was considered statistically significant.

Results:

A total of 301 participants responded. Significant differences were observed between genders when asked about being comfortable with treating oral mucosal lesions in their practice (p-value: .019), and males were more convenient than females. A significant difference (p-value: .011) was observed between different educational levels when the participants were asked about the management of patients with oral mucosal lesions. Overall, the majority of participants rarely or never managed oral lesions. When comparing the different groups of participants, postgraduate residents responded more accurately (p-value: 007). Approximately 60% of all participants did not or rarely managed oral lesions in their practice.

Conclusion:

It was found that there was a lack of knowledge among dentists regarding the detection and treatment of oral mucosal lesions. This lack of knowledge can lead to unfavorable patient care and prognosis outcomes.

Squamous cell carcinoma around a subperiosteal implant in the maxilla and the association of chronic mechanical irritation and peri-implantitis: a case report

Background

As carcinogenic risk factors, environmental factors can be classified into physical, biological, and chemical factors. Subperiosteal implants (SIs) are associated with complications, such as framework exposure, infection, and fistula formation. A current hypothesis suggests that chronic mechanical irritation could be a co-factor in carcinogenesis, while peri-implantitis might be an initiating or promoting agent in the development of oral mucosal cancer. Herein, we report a case of squamous cell carcinoma (SCC) around a maxillary SI associated with chronic mechanical irritation and peri-implantitis as physical and biological factors, respectively.

Case presentation

A 74-year-old male patient presented with severe mobility of the SI and an undermined ulcer with induration, accompanied by a palatal fistula and the exposure of the metal framework. The SI had been placed on the maxilla for the occlusal reconstruction of the molar area 20 years ago. An incisional biopsy of the ulcer revealed SCC (cT4aN2cM0). Neoadjuvant chemotherapy was initiated, followed by bilateral neck dissection and partial resection of the maxilla with SI removal. Energy-dispersive X-ray analysis suggested that the SI was fabricated using pure titanium, and titanium was absent in the specimen. Scanning electron microscopy of the SI in contact with the SCC showed a few microcracks, suggesting pitting corrosion.

Discussion

Chronic mechanical irritation due to the mobility of an improperly designed SI can be a physical factor, and prolonged peri-implantitis without regular maintenance can be a biological factor in carcinogenesis. Improperly designed main struts and a large masticatory force in the molar area resulted in deterioration of the retention and mobility of the SI. The screw and framework frequently moved on mastication and came in direct contact with the ulcer as chronic mechanical irritation. Bacterial invasion into the subperiosteal space expanded by the mobility of the metal framework led to peri-implantitis. The influence of chemical factors was considered relatively small in this case since the patient had no history of smoking or drinking, and titanium was absent in the specimen. Therefore, it is conceivable that SCC can arise owing to persistent inflammation caused by chronic mechanical irritation and peri-implantitis as physical and biological factors, respectively.

Oral Lichen Planus: risk factors of malignant transformation and follow up. Ten years retrospective study

Background

Oral Lichen Planus (OLP) is an inflammatory chronic disease. Modified World Health Organization (WHO) diagnostic criteria (2003) suggest diagnosing OLP both clinically and histologically. Furthermore, it is known the potential of malignant transformation of OLP, especially those affecting mucosa. Aims of this retrospective study on 100 patients were i) to estimate the timing of transformation of OLP lesions in OSCC in a cohort of patients observed between 2008 and 2018; ii) to assess risk factors of OLP patients diagnosed with OSCC; iii) to analyse forms of OLP evolved in cancer.

Material and Methods

A database of 100 patients diagnosed with OLP was evaluated and clinical, histological features of lesions, habits of patients and systemic diseases were analysed in a follow up ranged between 5 and 10 years.

Results

Mean time of malignant transformation was 31,62± 18,26 months; however, 4 malignant transformations out of 8 occurred about after 4 years of observation. Furthermore, Odds ratios for risk factors showed an association between malignant transformation and location.

Conclusions

More focused attention on follow-up scheduling and designing could be a valuable resource in early diagnosis and cancer prevention in OLP patients.

Key words:Oral Lichen Planus, Oral Cancer, Malignant transformation, risk factors.

Diagnosis of an adenocarcinoma of Müllerian origin made as a result of its metastasis in the mouth floor

Metastases derived from primary tumours distant to the oral and maxillofacial region account for only 1% of all malignancies at that location, usually with a poor prognosis. In women, the primary tumours that most frequently metastasise to the oral cavity are breast adenocarcinomas affecting the jawbones and soft tissues (41% and 24%, respectively), followed by adrenal glands and female genital organs to the jawbones (8%), and female genital organs to the soft tissues (15%). Metastatic tumours of the mouth are a challenging diagnosis because of their exceptional occurrence. We report on the case of an 83-year-old woman who consulted for a bleeding ulcerated tumour on the floor of the mouth. A biopsy-confirmed metastasis of an adenocarcinoma of Müllerian origin. The oral lesion was the first sign of undetected cancer. The patient agreed to surgical resection and was further referred to palliative care for her symptoms.

Noninvasive Imaging Methods to Improve the Diagnosis of Oral Carcinoma and Its Precursors: State of the Art and Proposal of a Three-Step Diagnostic Process

Simple Summary

Oral squamous cell carcinoma (OSCC) accounts for 90–95% of malignant tumors of the lip and oral cavity and is associated with high mortality in the advanced stages. Early diagnosis is a challenge for oral pathologists and dentists, due to the ambiguous appearance of early OSCC, which is often misdiagnosed, mistreated, and associated with diagnostic delay. The gold standards for OSCC diagnosis are biopsy and histopathological assessment, but these procedures are invasive and time-consuming. Adjunctive noninvasive techniques allow the definition of the malignant features of a suspicious lesion in real time and noninvasively, thus improving the diagnostic procedure. The present review aimed to focus on some of the main promising noninvasive imaging techniques, to highlight their perspective adoption in a three-step diagnosis, which is idealistically faster and better, as well as enables the patient’s compliance.

Abstract

Oral squamous cell carcinoma (OSCC) is the most prevalent form of cancer of lips and oral cavity, and its diagnostic delay, caused by misdiagnosis at the early stages, is responsible for high mortality ratios. Biopsy and histopathological assessment are the gold standards for OSCC diagnosis, but they are time-consuming, invasive, and do not always enable the patient’s compliance, mainly in cases of follow-up with the need for more biopsies. The use of adjunctive noninvasive imaging techniques improves the diagnostic approach, making it faster and better accepted by patients. The present review aims to focus on the most consolidated diagnostic techniques, such as vital staining and tissue autofluorescence, and to report the potential role of some of the most promising innovative techniques, such as narrow-band imaging, high-frequency ultrasounds, optical coherence tomography, and in vivo confocal microscopy. According to their contribution to OSCC diagnosis, an ideal three-step diagnostic procedure is proposed, to make the diagnostic path faster, better, and more accurate.

Cytogenetic analysis of genetic damage in young individuals exposed to chronic mechanical irritation in the lateral border of the tongue due to sharp teeth - a novel study

Background

Chronic inflammation is estimated to contribute to approximately 25% of human cancers. Inflammation can be induced by chronic mechanical irritation which can lead to oral pre-cancer and oral cancer. Though many studies have been conducted to identify the genetic damage in oral cancer or dysplastic stages, no study has been conducted so far on early detection of genetic damage in healthy individuals presenting with sharp teeth in contact with the lateral border of the tongue.

Objective

The study is aimed at analyzing the genetic damage (micronuclei) in healthy individuals with sharp teeth in contact with the lateral border of the tongue causing chronic mechanical irritation.

Methods

The study group included 75 clinically healthy individuals with sharp teeth in contact with the lateral border of the tongue and 25 clinically healthy individuals with normal teeth in contact with the lateral border of the tongue as a control group. Brush samples of epithelial cells were collected, then spread over clean glass slide and fixed in 100% alcohol, stained with rapid PAP and analyzed under the light microscope. The exfoliated cells were examined to detect micronuclei.

Results

Micronuclei frequency was found to be increased in the study group where sharp teeth were in contact with the lateral border of the tongue of healthy individuals without deleterious habits such as usage of tobacco in smoking/smokeless form, areca nut chewing or alcohol consumption.

Conclusions

Cytogenetic analysis is a simple and scantly invasive technique allowing clinicians the early detection of DNA damage in patients with sharp teeth and subsequently preventing carcinogenesis by proper treatment and follow-up.

Autophagy-A Hidden but Important Actor on Oral Cancer Scene

The duration of denture use, oral hygiene, smoking and male sex were identified as risk factors for oral mucosal lesions. As it is well known, all the oral mucosal lesions associated with risk factors have an important degree of malignity. Chronic mechanical irritation can be another cause of oral cancer and it is produced by the constant action of a deleterious agent from the oral cavity. Autophagy represents a complex evolutionary conserved catabolic process in which cells self-digest intracellular organelles in order to regulate their normal turnover and remove the damaged ones with compromised function to further maintain homeostasis. Autophagy is modulated by mTOR kinase and indirectly by PI3K/AKT survival pathway. Due to its dual capacity to either induce cell death or promote cell survival, important evidence pointed that autophagy has a two-faced role in response to chemotherapy in cancer. In conclusion, understanding how to overcome cytoprotective autophagy and how to take advantage of autophagic cell death is critical in order to enhance the cancer cells sensitivity to particular therapeutic agents.

Factors Associated with Knowledge, Attitudes, and Practices Related to Oral Care Among the Elderly in Hong Kong Community

Background: The oral health of elderly populations is a significant concern, as it is closely linked to general health and health-related quality of life. Poor oral health exacerbates oral diseases, leading to an increased risk of non-communicable diseases and self-care dependence, particularly in the elderly, worldwide. Knowledge, attitudes, and practices (KAP) play influential roles in individual oral care. However, the evidence of KAP related to oral care among the elderly is still inadequate. Objective: This study aimed to examine KAP and their associated factors related to oral care among the elderly community. Methods: A cross-sectional descriptive design was used. The eligible subjects were recruited, using convenience sampling and snowball sampling. Results: A total of 385 elderly individuals were included, and 51.4% were women. The mean age was 71.66 (SD 6.28). Knowledge was reportedly poor, as more than 50% elderly answered several questions incorrectly. The mean attitude and practices scores were 44.94 (SD 6.33) and 68.90 (SD 10.44), respectively. There was a significant correlation among knowledge, attitudes, and practices (p < 0.001). Multivariable regression analysis revealed numerous factors had remarkably significant association with knowledge [R² = 0.30, F (4,380) = 11.96, p < 0.001], attitudes [R² = 0.28, F (6,378) = 9.27, p < 0.001], and practices [R² = 0.31, F (5,379) = 12.34, p < 0.001], particularly education levels, full-time employment, and self-care independence. Conclusions: Based on the KAP theoretical model, KAP are closely interrelated. Identified factors associated with KAP are useful to understand at-risk groups. Elderly individuals at lower education levels, with poor family support and inadequate self-care independence, have poor KAP related to oral care. Therefore, this study improves insight for health promotion developers, suggesting that more attention should be paid to at-risk elderly groups’ oral health. To enhance participation in dental care and improve oral care performance in the elderly, educational program containing oral health knowledge should be offered to at-risk groups. Family support and involvement are also important for improving oral care among elderly individuals.

Tobacco, Alcohol and Family History of Cancer as Risk Factors of Oral Squamous Cell Carcinoma: Case-Control Retrospective Study

The aim of the study is to observe retrospectively the correlation between Oral Squamous Cell Carcinoma (OSCC) and risk factors; including tobacco, alcohol and Family History of Cancer (FHC). A total of 478 patients were included retrospectively from the database of the Department of Oral Sciences and Maxillofacial Surgery, Sapienza University of Rome. A Test Group (TG) consisted of 239 patients with a confirmed diagnosis of OSCC. A Control Group (CG) consisted of 239 patients without history and/or diagnosis of oral cancer. The logistic regression models were used to calculate the adjusted Odd Ratios (ORs) associated with alcohol, tobacco and FHC; including the General Family History of Cancer (GFHC) and Family History of Head and Neck Cancer (FHHNC) and their 95% Confidence Intervals (CI). The high rate of tobacco consumption was associated with an OR of 1.035 (95% CI 1.001–1.070) and a statistical significance (p = 0.041). Drinker patients showed a significant risk of developing OSCC (p = 0.05) and the OR was 1.035 (95% CI 1.010–1.061). The GFHC was associated with a marginal risk of OSCC with an OR of 1.095 (95% CI 0.953–1.259), without significance (p = 0.199). The FHHNC showed a notable risk increase with an OR of 1.871 (95% CI 0.902–3.882), without significance (p = 0.092). Alcohol and tobacco may be associated with an increase in the risk of OSCC.

Evidence for chronic mechanical irritation as a causative factor in oral cancer: application of Bradford Hill criteria

Chronic mechanical irritation (CMI) of the oral mucosa has been proposed as a risk factor for oral cancer (OC), but the available evidence is limited and controversial. One of the main limitations is the lack of proper criteria to define and classify CMI. The objective of this narrative review is to apply the Bradford Hill causality criteria to assess such an association based on the published literature. The level of evidence is not conclusive, mainly due to methodological shortcomings. Hence, to systematize future CMI research, we recommend the following items should be included: a clear definition for CMI, ascertaining any temporal association, recording all types of CMI: dental, prosthetic, and functional. Finally, it is important to emphasize that studies dealing with risk factors for OC should not only be restricted to established factors such as tobacco, alcohol, and areca nut consumption but should also consider other factors including the patient’s dental condition. In this regard, CMI, tooth loss, periodontal disease, and many others could be included. The causality criteria set out by Bradford Hill could be used for studying different controversial risk factors for OC.

Association between poor oral health and gastric cancer: A prospective cohort study

Poor oral health may be involved in the pathogenesis of gastric cancer, however, some aspects have not been explored. Further, for previously studied aspects, for example, tooth-loss, the findings are inconsistent. We conducted a prospective cohort study of 19,831 participants from Uppsala, Sweden, cancer-free at baseline in 1973-1974 and followed until 2012 through linkage to national registers. We found that individuals with fewest teeth at baseline had an increased risk of gastric cancer relative to subjects with all examined teeth present (p = 1.75e-2). Presence of denture-associated lesions was also associated with an increased risk of gastric cancer (p = 1.00e-4). However, these excess risks significantly varied with attained age; estimated hazard ratio (HR) at attained age 50 for tooth loss was 4.24 [95% confidence interval (CI) 1.83-9.80] and 5.91 (95% CI 2.76-12.63) for denture-associated lesions, decreasing at an estimated 4% and 6% per year respectively, resulting in HR of 1.54 (95% CI 0.90-2.64) for tooth loss and HR 1.29 (95% CI 0.90-1.85) for denture-associated lesions at attained age 75. No increased risk of gastric cancer was found for individuals with higher levels of dental plaque, or with Candida-related or tongue lesions. In conclusion, tooth-loss and denture-associated lesions are associated with increased risks of gastric cancer. Previous conflicting findings of tooth-loss and gastric cancer risk may partly be explained by the age-varying relative risk of gastric cancer.

In situ delivery of corticosteroids for treatment of oral diseases

In many mucocutaneous disorders, corticosteroids therapy is currently central. Systemic therapy is restricted to severe disorders whereas topical applications are considered as the first-line treatment. The oral cavity environment, the medication form and other factors related to the delivery method are key factors for the therapy efficiency and effectiveness. Current marketed medications are not able to avoid wrong drug exposure and scarce patients' compliance. Innovative in situ delivery systems are able to prolong the drug retention time on the mucosa and to avoid the drawbacks of conventional formulations. This review is intended to give a general overview of oral mucocutaneous pathologies and highlight the potential of new technologies in designing innovative delivery systems able to release corticosteroids in situ for the treatment of various oral cavity disorders.

Oral cancer associated with chronic mechanical irritation of the oral mucosa

Background

Most of the studies dealing with Chronic Mechanical Irritation (CMI) and Oral Cancer (OC) only considered prosthetic and dental variables separately, and CMI functional factors are not registered. Thus, the aim of this study was to assess OC risk in individuals with dental, prosthetic and functional CMI. Also, we examined CMI presence in relation to tumor size.

Material and Methods

A case-control study was carried out from 2009 to 2013. Study group were squamous cell carcinoma cases; control group was patients seeking dental treatment in the same institution.

Results

153 patients were studied (Study group n=53, Control group n=100). CMI reproducibility displayed a correlation coefficient of 1 (p<0.0001). Bivariate analysis showed statistically significant associations for all variables (age, gender, tobacco and alcohol consumption and CMI). Multivariate analysis exhibited statistical significance for age, alcohol, and CMI, but not for gender or tobacco. Relationship of CMI with tumor size showed no statistically significant differences.

Conclusions

CMI could be regarded as a risk factor for oral cancer. In individuals with other OC risk factors, proper treatment of the mechanical injuring factors (dental, prosthetic and functional) could be an important measure to reduce the risk of oral cancer.

Key words:Oral cancer, risk factors, chronic mechanical irritation, tumor size, case-control study.