Comparison of demographic characteristics, socioeconomic risk factors, and lifestyle habits between the cases and control groups

Finally, diet was recognized as a likely factor influencing the distribution of cases and controls. The majority of OCs were found on the buccal mucosa (54%), followed by gingiva/gums (18%), tongue (11%), floor of the mouth (8%), labial mucosa (6%), and palate (3%). Analysis of dental status revealed that the case group had a higher proportion of completely edentulous patients compared with the control group. The control group exhibited a significantly higher rate of filled teeth (F), whereas the case group had a higher rate of missing teeth (M). There was no significant difference in the number of decayed teeth (D) between the two groups. The mean DMFT value was 21.65 ± 8.46 in the case group and 14.18 ± 8.26 in the control group ([Table 2]). A significant correlation was found between the occurrence of OC and periodontitis. The occurrence of OC was 57.1%-among patients with periodontitis, whereas those without periodontal disease had a lower incidence of 26.6%. A significant correlation was identified, indicating that as the severity of periodontitis increased, there was a corresponding rise in the risk of OC development ([Figs. 1] and [2]). The majority of OC patients, constituting 72.1% of the case group, were diagnosed with stage 4 periodontitis. In contrast, in the control group, most individuals had stage 2 periodontitis, accounting for 51.6%. Significant disparities were observed in the mean values of CAL and PPD between the two groups. The case group demonstrated substantially higher values, with CAL at 6.2 ± 1.3, compared with 2.8 ± 1.1 in the control group. Similarly, the mean values of PPD and bleeding on probing percentage (BOP%) were higher among cases compared with controls. The RI (iABL) index scoring codes was 2 and 3 (moderate to severe alveolar bone loss) among controls ([Figs. 3] and [4]) and 3 and 4 (severe to very severe alveolar bone loss) among cases ([Figs. 1] and [2]). In the case group, there were more completely edentulous patients (n = 6) compared with the control group (n = 3). Among the completely edentulous patients, 11.3%-were diagnosed with OC. Logistic regression analysis confirmed that the prevalence and severity of periodontitis were statistically significant factors.

| Fig 1 : Clinical and radiographic image of a 54-year-old female patient with cancer of the lower right alveolus with no known risk factors apart from periodontitis.

| Figure 2: Clinical and radiographic images of a 36-year-old female patient with cancer of the upper right alveolus with no known risk factors other than periodontitis.

| Figure 3: Clinical and radiographic images of a 48-year-old female patient with cancer of the lower right alveolus and the floor of the mouth with no known risk factors other than periodontitis.

| Figure 4: Clinical and radiographic images of a 40-year-old male patient with cancer of the left lateral border of the tongue and the floor of the mouth with no known risk factors other than periodontitis.

Comparison of periodontal staging, CAL, PPD, BOP, RI (iABL), SLPI, DMFT INDEX between case and control groups

Abbreviations: BOP, bleeding on probing; CAL, clinical attachment loss; DMFT, decayed, missing, and filled teeth; iABL, interproximal alveolar bone loss; PPD, probing pocket depth; RI, radiographic index; SLPI, Silness–Löe plaque index.

Discussion

India has the highest number of OC cases globally and is recognized as the global epicenter of this disease. Besides tobacco use, risk factors include the consumption of areca nut, alcohol, diet, human papillomavirus (HPV) infection, advancing age, male gender, and socioeconomic factors. Notably, periodontitis is also widespread in India, and both OC and periodontitis share common established risk factors like tobacco use, poor OH, etc.[6] Periodontitis is a persistent inflammatory condition that affects the supporting structures of the teeth, resulting in the deterioration of periodontal tissues leading to tooth mobility and tooth loss. It is known that the impact of periodontitis extends beyond the confines of the oral cavity, potentially giving rise to systemic consequences like diabetes, cardiovascular diseases, and cancer.[3] Although complex, evidence suggests a connection between periodontal disease and OC due to the considerable role of inflammation in both conditions.

In the present study, patients with periodontitis had a higher rate of OC (63.9%) compared with those without periodontitis (32.4%), and a large proportion of OC patients (72.9%) were diagnosed with stage 4 periodontitis, in contrast to just 30.6%-of the control group. Five (7.9%) of the OC cases had severe periodontitis (stages III and IV) as their only identified risk factor. This finding underscores the potential unique contribution of periodontitis to OC susceptibility. The chronic inflammation associated with periodontitis may create an environment conducive to carcinogenesis, even in the absence of other major risk factors such as tobacco use, significant alcohol consumption, poor diet, or genetic predisposition.[7] Although 7.9%-is a relatively small percentage, it is substantial in identifying periodontitis as a potential independent risk factor for OC. The present study confirms a significant correlation between OC and periodontitis, aligning with the findings of Javed et al's 2016 systematic review.[8] This highlights the importance of monitoring and managing periodontal health to potentially reduce the risk of OC in susceptible individuals.

The study also revealed that a notable number of individuals diagnosed with OC exhibited advanced periodontitis (stages III and IV), in stark contrast to the control group, which showed a lower prevalence of severe periodontitis. CAL was markedly elevated in cases of OC, as demonstrated by a substantially higher mean CAL of 5.7 mm, contrasting sharply with controls in whom the mean CAL was 2.7 mm. Likewise, PPD displays notable distinctions between cases (5 mm) and controls (2.2 mm). This considerable variance underscores the existence of more profound periodontal pockets among individuals with OC, highlighting the potential gravity of periodontal involvement in this cohort. The study demonstrates a distinct positive correlation between the severity of periodontitis and the prevalence of OC, consistent with the results of Komlós et al.[9] Severe periodontitis and OC may be linked through several mechanisms. Chronic inflammation caused by severe periodontitis can facilitate cancer development by leading to DNA damage and mutations. The development of a malignant lesion is often linked to inflammation, particularly due to oxidative damage to the cell's DNA.[10] [11] Periodontitis is distinguished by increased levels of proinflammatory cytokines, acute phase proteins, and proteinases in the bloodstream.[12] Moreover, inflammatory mediators such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) found in periodontal lesions are linked to carcinogenesis.[13] Recent research indicates a direct connection between pathogens associated with periodontal disease and the onset of OC. Additionally, certain bacteria involved in periodontitis, such as Porphyromonas gingivalis, have been detected in higher levels in OC tissues, potentially contributing to cancer development.[14] Periodontal pockets could serve as reservoirs for cytomegalovirus, HPV, and Epstein–Barr virus, all of which are agents linked to OC.[15] This lends support to the hypothesis proposed by Sahingur et al, indicating that the severity of periodontitis and changes in the oral microbiome play a role in creating a favorable environment for the onset of OC.[9]

Shared risk factors, like tobacco and alcohol use, further complicate the relationship, as these can exacerbate both conditions. Poor OH associated with periodontitis may also delay OC detection as it may go unnoticed.[16] Thus, managing severe periodontitis and maintaining good oral health are crucial for reducing the risk of OC. Advanced periodontitis has the potential to compromise the local immune response, impacting the body's ability to regulate abnormal cell growth and potentially contributing to OC development. The proposition that periodontitis and OC may follow a sequential progression in certain cases is plausible, where severe periodontitis could serve as an early indicator or a contributing factor in the sequence of events leading to the development of OC.[17]

Radiographs, especially panoramic radiographs, facilitate precise assessment of the interproximal alveolar bone, aiding in the localization and measurement of bone loss. Radiographic indices like RI(iABL) facilitate the quantification of iABL.[18] The codes likely correspond to specific degrees of bone loss, allowing for a standardized and measurable assessment of severity. The RI (iABL) distribution shows a marked difference between cases and controls, with a higher prevalence of advanced iABL in OC patients, suggesting a potential link between OC and more severe bone loss. BOP is a common clinical indicator of periodontal inflammation, and its elevated levels among cases implies the need for attention to periodontal health in this population. The higher mean SLPI in cases, compared with controls, points to an increased level of dental plaque among OC patients. Elevated plaque levels not only impact the condition of the teeth and gums but also have systemic implications.[19] Consideration should be given to interventions aimed at improving OH and reducing plaque accumulation in OC patients to maintain overall oral health and potentially mitigate associated risks.

The observation that cases have a significantly higher mean DMFT index compared with controls indicates a higher prevalence of dental caries and tooth loss among individuals diagnosed with OC. Several factors could lead to the higher DMFT index observed in OC cases, including the effects of cancer treatments on oral health, potential alterations in salivary flow, and the presence of risk factors like tobacco use and inadequate OH. Additionally, there was a greater number of completely edentulous individuals among cases compared with controls, indicating a higher prevalence of complete tooth loss primarily associated with periodontitis among OC patients.

The findings of the study suggest that OC patients (cases) exhibit higher prevalence of periodontal conditions, including advanced periodontitis stages, higher CAL and PPD values, greater iABL, increased BOP, elevated SLPI, a higher DMFT index, and a higher rate of complete edentulism compared with the control group. These findings highlight the potential interplay between periodontal health and OC, emphasizing the relevance of comprehensive oral health assessments in patients.[20] It is important to note that while there is evidence suggesting a potential association, not all individuals with periodontitis develop OC, and the relationship is likely influenced by a combination of genetic, environmental, and lifestyle factors.[22] [21]

This study offers novel insights into the association between periodontitis and OC, particularly within the Indian population, which experiences high rates of both conditions. It quantitatively establishes that individuals with periodontitis, especially in advanced stages, face a significantly higher risk of developing OC. The study integrates both clinical and radiographic evaluations to show that severe periodontitis is linked to increased OC risk, influenced by socioeconomic, lifestyle, and OH factors. It suggests that periodontitis may be an independent risk factor for OC, regardless of tobacco and alcohol use, and offers region-specific data to guide preventive strategies and further research.

Conclusion

This study highlights the complex link between OC and periodontal health, showing that poor OH and plaque buildup create chronic inflammation that may promote OC development. The findings of this study support the notion that periodontitis is an independent risk factor for OC, with the risk increasing as periodontal disease progresses. Preventive measures for periodontal disease include regular dental visits and maintaining optimal OH. Dentists can contribute to reducing the risk of OC by evaluating and addressing patients' lifestyle and habits and monitoring compromised periodontal health. Further research and longitudinal studies are crucial to deepening our understanding of the intricate interplay between OC and periodontitis, laying the groundwork for more precise and effective preventive strategies in clinical practice.

Conflict of Interest

None declared.