Smoking and Oral Disease: The Effect of Smoking Cessation on Periodontal Treatment

Tobacco smoking, and in particular cigarette smoking, is recognized as the most important environmental risk factor for human morbidity and mortality1Samet JM. Tobacco smoking: the leading cause of preventable disease worldwide. Thorac Surg Clin. 2013;23(2):103-12 https://www.ncbi.nlm.nih.gov/pubmed/23566962.. Smoking has been identified as a major risk factor for many diseases, particularly lung cancer and cardiovascular disease, as well as many other malignancies, vascular diseases and pulmonary diseases. In the United States, it has been estimated that one in five deaths are attributable to smoking cigarettes. The total number of deaths attributable to cigarette smoking has been estimated to be 480,000 per year, with men accounting for 57% of the total.2Centers for Disease Control and Prevention. Smoking & Tobacco Use. https://www.cdc.gov/tobacco/index.htm. Accessed January 14, 2024.^,3Centers for Disease Control and Prevention. Tobacco-Related Mortality. https://archive.cdc.gov/#/details?q=https://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/tobacco_related_mortality/index.htm&start=0&rows=10&url=https://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/tobacco_related_mortality/index.htm. Accessed January 14, 2024.

Change in life expectancy is another way to assess the detrimental effects of smoking. The Centers for Disease Control and Prevention estimates that life expectancy is approximately 10 years less for smokers versus non-smokers. When examined by risk of death, men have a 17 times higher risk of dying from pulmonary disorders (bronchitis, emphysema) than non-smokers. Further, male smokers are at 23 times higher risk of dying from certain cancers (trachea, bronchitis, lung). For women, the increased risk is 12 times higher, and greater than 12 times higher, respectively. Lastly second-hand smoke is estimated to cause more than 40,000 deaths annually from heart disease and lung cancer.2Centers for Disease Control and Prevention. Smoking & Tobacco Use. https://www.cdc.gov/tobacco/index.htm. Accessed January 14, 2024.^,3Centers for Disease Control and Prevention. Tobacco-Related Mortality. https://archive.cdc.gov/#/details?q=https://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/tobacco_related_mortality/index.htm&start=0&rows=10&url=https://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/tobacco_related_mortality/index.htm. Accessed January 14, 2024.

Cigarette smoking also has significant deleterious effects on oral health. Smoking is the prime environmental risk factor for both periodontal disease and oral squamous cell carcinoma. A review by Jan Bergström,4Bergstrom J. Tobacco smoking and chronic destructive periodontal disease. Odontology. 2004;92(1):1-8 https://www.ncbi.nlm.nih.gov/pubmed/15490298. who was a pioneer in identifying (cigarette) smoking as a major risk factor for periodontitis, emphasized that smokers demonstrated greater bone loss, loss of attachment and deeper probing depths, than non-smokers. Aligned with those findings, smokers also demonstrated greater tooth loss. Bergström summarized the literature by noting a range of 5-to-20-fold increase in periodontal disease for smokers, with differences attributable to the definition of periodontal disease and smoking exposure. He also observed that smokers have a poor or no response to periodontal treatment, as well as a tendency to relapse after treatment.

Bergström also noted that existing data indicated that the periodontal microflora from patients with periodontitis who smoke does not differ from that seen in non-smokers with periodontitis. Therefore, the underlying mechanisms that account for the more severe periodontitis in smokers have been attributed to an altered host response, be that the vascular response, inflammatory response or healing capacity.

A more recent review of 14 studies examining the risk of periodontitis for people who smoke included a meta-analysis. The risk of periodontitis was determined to be 85% higher in smokers than non-smokers.5Leite FRM, et al. Effect of smoking on periodontitis: a systematic review and meta-regression. Am J Prev Med. 2018;54(6):831-41 https://www.ncbi.nlm.nih.gov/pubmed/29656920. In addition to its effect on periodontitis, cigarette smoking has also been associated with an increased risk of apical periodontitis, a sequalae of endodontic involvement.6Aminoshariae A, et al. The association between smoking and periapical periodontitis: a systematic review. Clin Oral Investig. 2020;24(2):533-45 https://www.ncbi.nlm.nih.gov/pubmed/31773370..

The role of cigarette smoking in the development of oral squamous cell carcinoma (OSCC) is well established.7Petersen PE. Oral cancer prevention and control–the approach of the World Health Organization. Oral Oncol. 2009;45(4-5):454-60 https://www.ncbi.nlm.nih.gov/pubmed/18804412. Oral cancer development can be influenced by several other identified risk factors, including alcohol intake8Ogden GR. Alcohol and oral cancer. Alcohol. 2005;35(3):169-73 https://www.ncbi.nlm.nih.gov/pubmed/16054978. and use of betel quid.9Edirisinghe ST, et al. The risk of oral cancer among different categories of exposure to tobacco smoking in Sri Lanka. Asian Pac J Cancer Prev. 2022;23(9):2929-35 https://www.ncbi.nlm.nih.gov/pubmed/36172654. Adding to the challenge, a systemic review and meta-analysis has indicated that secondhand smoke can be associated with an increased risk for oral cancer, with an odds ratio of 1.51, with greater risk being associated with a longer duration of smoking (10 to 15 years).10Mariano LC, et al. Secondhand smoke exposure and oral cancer risk: a systematic review and meta-analysis. Tob Control. 2022;31(5):597-607 https://www.ncbi.nlm.nih.gov/pubmed/33903278. Note, however, that there has been a marked increase in patients diagnosed with oral/pharyngeal squamous cell carcinoma who are younger and do not smoke. This increase has been attributed to infection with the human papilloma virus, and in particular the HPV 16 variant.11Giraldi L, et al. Infection with Human Papilloma Virus (HPV) and risk of subsites within the oral cancer. Cancer Epidemiol. 2021;75:102020 https://www.ncbi.nlm.nih.gov/pubmed/34509873..

Smoking has been identified as a risk factor for dental implant complications and implant failure. This extended to failure of dental implants placed into the maxillary sinus that previously had received a bone graft.12Baig MR, Rajan M. Effects of smoking on the outcome of implant treatment: a literature review. Indian J Dent Res. 2007;18(4):190-5 https://www.ncbi.nlm.nih.gov/pubmed/17938497. A systematic review and meta-analysis included 35 studies and found increased risk of implant complications and implant failure in patients who smoked.13Abt E. Smoking increases dental implant failures and complications. Evid Based Dent. 2009;10(3):79-80 https://www.ncbi.nlm.nih.gov/pubmed/19820742. In a more recent example, implant outcomes were compared between smokers and non-smokers. Both peri-implant mucositis and peri-implantitis were considered. The risk of peri-implantitis increased with increased smoking exposure. Smoking exposure, measured in pack-years, was positivity associated with an increased risk of complications. For former smokers, the risk of implant complications approached that of non-smokers, but only after more than 20 years of abstinence.14Martinez-Amargant J, et al. Association between smoking and peri-implant diseases: a retrospective study. Clin Oral Implants Res. 2023;34(10):1127-40 https://www.ncbi.nlm.nih.gov/pubmed/37523460.

Lastly, certain types of smokeless tobacco have been associated with an increased risk of OSCC, but the relative risk is different in various parts of the world and depends on the composition of the product.15Asthana S, et al. Association of smokeless tobacco use and oral cancer: a systematic global review and meta-analysis. Nicotine Tob Res. 2019;21(9):1162-71 https://www.ncbi.nlm.nih.gov/pubmed/29790998. Specifically,

• Gatkha: relative risk (RR) of OSCC = 8.67. A type of chewing tobacco containing areca nut and slaked lime.
• Pan tobacco/liquid betel nut: RR=7.18. A type of chewing tobacco with other carcinogenic components.
• Oral snuff: RR=4.18. Finely ground tobacco which is inhaled (”snorted”).
• Mainpuri tobacco: RR=3.32. Another type of tobacco and betel nut product.
• Snus: RR=0.86. A tobacco product developed in Sweden. It is usually sold in packets and is steam pasteurized but not fermented. While still considered harmful, it is an alternative to other types of smokeless tobacco and is used as an alternative to smoked tobacco.

When a dental patient presents to a dental office, a health history is completed. Medical conditions and diagnoses, current prescriptions and over-the-counter medications are listed. It is also critical to review the patient’s habits that can adversely influence oral health, and risk factors for oral disease. These include use of tobacco products (cigarette, cigar and pipe smoking, smokeless tobacco) as well as recreational drug use (i.e., smoking marijuana) and alcohol intake.

When oral disease is detected, and treatment is required (i.e., periodontitis requiring periodontal therapy, missing teeth to be replaced by dental implants), it is important for the dental healthcare provider to inquire about the patient’s willingness to stop smoking (smoking cessation). However, tobacco use, especially when inhaled, is a challenging habit to break. Nicotine is a highly addictive alkaloid. The issue of smoking cessation activities by health professionals who treat patients who smoke has been a topic of considerable focus.

Considering that 11.5% of adults in the United States are cigarette smokers, and the enormous toll smoking takes on the lives of those who smoke as well as the cost of caring for diseases caused by smoking,16Centers for Disease Control and Prevention. Smoking & Tobacco Use. Cigarette Smoking in the U.S. https://www.cdc.gov/tobacco/data_statistics/fact_sheets/fast_facts/cigarette-smoking-in-the-us.html. Accessed January 14, 2024. all health professionals must inquire about willingness of their patients who smoke to quit.

The Centers for Disease Control and Prevention publishes data on the health of the U.S. population, including statistics on smoking and smoking cessation.17Centers for Disease Control and Prevention. Smoking & Tobacco Use. Smoking Cessation: Fast Facts. https://www.cdc.gov/tobacco/data_statistics/fact_sheets/cessation/smoking-cessation-fast-facts/index.html. Accessed January 14, 2024. The most recent data includes the following:

• Nearly 70% of adults who smoke stated that they want to quit the habit.
• More than half of adults who smoke stated that they tried to quit the habit in the last year.
• Less than 10% of adults who attempt to quit smoking in one year are successful.
• For those smokers who had a medical visit, more than 40% reported that they did not receive information on counseling about smoking cessation.

This essay will examine one specific question in this larger context. Since smoking is an important risk factor for periodontitis, and if periodontitis is detected and treatment is recommended, what effect will smoking cessation have on the outcome?

Smoking Cessation and Periodontal Treatment Outcomes

The importance of healthcare providers being advocates for smoking cessation for their patients has been repeatedly emphasized. A Cochrane review of different approaches to smoking cessation in primary medical care indicated that professional counseling by someone other than a physician, and providing free medications, were associated with improved rates of quitting.18Lindson N, et al. Strategies to improve smoking cessation rates in primary care. Cochrane Database Syst Rev. 2021;9(9):CD011556 https://www.ncbi.nlm.nih.gov/pubmed/34693994. Another Cochrane review examined the effectiveness of smoking cessation efforts by dental professionals.19Holliday R, et al. Interventions for tobacco cessation delivered by dental professionals. Cochrane Database Syst Rev. 2021;2(2):CD005084 https://www.ncbi.nlm.nih.gov/pubmed/33605440. Quit rates increased with the provision of this therapy by dental professionals. These rates improved when behavioral therapy was supplemented with pharmacological therapy (i.e., nicotine replacement therapy, e-cigarettes). Examining the actual percentage change over one year, a study from Australia found that smoking cessation therapy provided in dental settings (counseling and pharmacotherapy) achieved a quit rate of 18%, a reduction in usage rate of 34%, no change in 42%, and relapse in 6% of participants.20Sujatha S, et al. Long-term follow-up of tobacco cessation intervention in a dental setting: a randomized trial. J Cancer Res Ther. 2023;19(Supplement):S0 https://www.ncbi.nlm.nih.gov/pubmed/37147945.

However, despite evidence that meaningful rates of cessation and reduction can be realized by dental professionals, smoking cessation activities by dentists are not widely practiced. A study from Australia found that while 90% of providers asked about smoking, only about 50% aided patients who wished to quit. This assistance took the form of referral to a Quitline, or referral to a medical provider.21Ford P, et al. Survey of Australian oral health practitioners and their smoking cessation practices. Aust Dent J. 2015;60(1):43-51; quiz 128 https://www.ncbi.nlm.nih.gov/pubmed/25721277. Reasons for this low level of activity were lack of familiarity regarding pharmacotherapy, or no access to cessation resources, but not the time required or concerns about compensation. Data from a national survey in the U.S. indicated that only 25% of adults who visited a dentist received an oral cancer examination, and the percentage of smokers and minority groups who received counseling regarding smoking cessation were similarly quite low.22Nelson JL, et al. Patient-reported receipt of oral cancer screenings and smoking cessation counseling from US oral health care providers: National Health and Nutrition Examination Survey, 2015-2016. J Am Dent Assoc. 2019;150(12):995-1003 https://www.ncbi.nlm.nih.gov/pubmed/31761028. The authors called for increased emphasis and availability of programs to educate dentists about oral cancer screening and smoking cessation activities. The importance of engaging dental patients who smoke in smoking cessation activities should be viewed as an essential part of comprehensive dental care.

First, evidence demonstrates that periodontal treatment is less effective when provided to active smokers versus a control group. A systematic review with a meta-analysis demonstrated less reduction in probing depths and a similar gain in the clinical attachment level in the smoking versus the non-smoking groups following non-surgical periodontal treatment.23Chang J, et al. The impact of smoking on non-surgical periodontal therapy: a systematic review and meta-analysis. J Clin Periodontol. 2021;48(1):60-75 https://www.ncbi.nlm.nih.gov/pubmed/33022758. A recent study followed patients treated with non-surgical periodontal therapy over one year, comparing smokers and non-smokers. Both the severity of periodontal disease, as well as the smoking exposure, were considered. After one year, therapy proved least effective in heavy smokers with severe periodontitis. There was a dose response effect: as disease severity increased, and smoking exposure increased, the therapeutic response decreased.24Leite FRM, et al. Effect of smoking exposure on nonsurgical periodontal therapy: 1-year follow-up. J Dent Res. 2023;102(3):280-6 https://www.ncbi.nlm.nih.gov/pubmed/36333874.

Other studies have provided additional evidence for the adverse effect of smoking on the outcomes of periodontal treatment. After conservative periodontal treatment, and periodontal surgery if required, patients who did not smoke demonstrated significant reduction in periodontal pathogenic bacteria. For patients who smoked, there was no change in the levels of most of the bacterial species that characterize advanced periodontitis.25Van der Velden U, et al. Effect of smoking and periodontal treatment on the subgingival microflora. J Clin Periodontol. 2003;30(7):603-10 https://www.ncbi.nlm.nih.gov/pubmed/12834497. Similar findings were reported in a study of patients with periodontitis who received ultrasonic subgingival debridement with systematic amoxicillin and metronidazole. After 6 months, differences were seen in the clinical response to therapy, and smokers demonstrated higher levels of subgingival periodontal pathogens, and higher levels of inflammatory cytokines, as compared to non-smokers.26da Silva RVC, et al. Smoking negatively impacts the clinical, microbiological, and immunological treatment response of young adults with Grade C periodontitis. J Periodontal Res. 2022;57(6):1116-26 https://www.ncbi.nlm.nih.gov/pubmed/36050890. Further, heavy smoking (11 to 20 cigarettes/day) versus lighter smoking (1-10 cigarette/day) was associated with a less successful outcome of regenerative periodontal surgery.27Trombelli L, et al. Regenerative periodontal treatment with the single flap approach in smokers and nonsmokers. Int J Periodontics Restorative Dent. 2018;38(4):e59-e67 https://www.ncbi.nlm.nih.gov/pubmed/29889915. Smoking cessation is also associated with a reduced risk of tooth loss. A systematic review with a meta-analysis showed that former smokers had a rate of tooth loss comparable to persons who never smoked, which was significantly less than the rate of tooth loss for current smokers (RR = 2.6).28Souto MLS, et al. Effect of smoking cessation on tooth loss: a systematic review with meta-analysis. BMC Oral Health. 2019;19(1):245 https://www.ncbi.nlm.nih.gov/pubmed/31718636.

Of particular importance for both the dental patient and dental provider is the beneficial effect of previous smoking cessation on periodontal treatment outcomes. A systematic review with a meta-analysis concluded that the risk for either development of periodontitis, or progression of periodontitis, did not differ from that of persons who never smoked. Further, the risk of periodontitis was 80% greater in smokers than those individuals that had quit smoking.29Leite FRM, et al. Impact of smoking cessation on periodontitis: a systematic review and meta-analysis of prospective longitudinal observational and interventional studies. Nicotine Tob Res. 2019;21(12):1600-8 https://www.ncbi.nlm.nih.gov/pubmed/30011036. They also reported a greater gain of attachment and greater reduction on probing depth following periodontal treatment for patients that had quit smoking versus those that smoked. However, their review was limited to only 6 published papers. Two more recent reviews also examined this relationship. One review30Caggiano M, et al. Smoking cessation on periodontal and peri-implant health status: a systematic review. Dent J (Basel). 2022;10(9) https://www.ncbi.nlm.nih.gov/pubmed/36135157. included 7 papers, could not draw conclusions for either the effect of smoking cessation on periodontal treatment or treatment of complications around dental implants. The other31Duarte PM, et al. Impact of smoking cessation on periodontal tissues. Int Dent J. 2022;72(1):31-6 https://www.ncbi.nlm.nih.gov/pubmed/33653595. was a narrative review and while noting a paucity of well conducted clinical trials, was more positive regarding the beneficial effects of smoking cessation on outcomes of non-surgical periodontal treatment.

It is a challenge to conduct a true randomized controlled trial to assess the effect of smoking cessation on periodontal treatment outcomes because that would mean that half the patients would be treated without having received instruction in smoking cessation. However, advising a patient to stop smoking is a professional responsibility, and if successful would eliminate an important risk factor for many systemic and oral diseases. There is some evidence that supports the potential value of such programs in the dental office. A multicenter study from Japan demonstrated that over a period of 6 months, patients requiring periodontal treatment, who smoked and completed a smoking cessation program prior to treatment, demonstrated greater improvement in clinical parameters (probing depth, attachment level and bleeding following probing) as compared to those patients who continued to smoke.32Nakayama Y, et al. A multicenter prospective cohort study on the effect of smoking cessation on periodontal therapies in Japan. J Oral Sci. 2020;63(1):114-8 https://www.ncbi.nlm.nih.gov/pubmed/33298640. Furthermore, examining the effectiveness of smoking cessation advice delivered by dental professionals, another report from Japan evaluated patients who were at risk for development a malignant oral lesion or with periodontitis, and who were being evaluated for dental implants. All had completed a smoking cessation program related to their dental care.33Nagao T, et al. A multicentre tobacco cessation intervention study in the dental setting in Japan. Int Dent J. 2022;72(1):123-32 https://www.ncbi.nlm.nih.gov/pubmed/33743994. Over one year, one-third of the patients had successfully quit smoking.

Smoking Cessation Resources for Dental Professionals

The terrible toll that smoking takes on the health of Americans, as well as the cost to the U.S. economy, suggest the critical importance of smoking prevention, and for patients who smoke, smoking cessation. All health professionals should be engaged in these activities, especially oral healthcare professionals.

The medical literature addressing smoking cessation activities is extensive. A systematic review of smoking cessation activities for patients with cancer included 23 studies published by research groups in different countries. No one intervention was seen to be most effective, and important variables that were identified include the frequency of conversations about quitting and the use of pharmacotherapy, specifically varenicline (the brand name is Chantix; reduces cravings and symptoms of withdrawal).34Frazer K, et al. Systematic review of smoking cessation interventions for smokers diagnosed with cancer. Int J Environ Res Public Health. 2022;19(24) https://www.ncbi.nlm.nih.gov/pubmed/36554894. See Table 1 for a list of pharmacologic approaches to smoking cessation. Another concern is the effect of smoking cessation on mental health and if withdrawal leads to development of psychological disorders. A systematic review and meta-analysis included more than 100 studies and did not observe worsening of mental health in association with quitting.35Taylor GM, et al. Smoking cessation for improving mental health. Cochrane Database Syst Rev. 2021;3(3):CD013522 https://www.ncbi.nlm.nih.gov/pubmed/33687070. Further, studies have also examined differences between quit rates for men and women. A systematic review could not identify any obvious differences between the sexes.36Smith PH, et al. Sex/gender differences in smoking cessation: a review. Prev Med. 2016;92:135-40 https://www.ncbi.nlm.nih.gov/pubmed/27471021.

Nevertheless, smoking cessation activities in medical settings can be effective, even brief interventions can increase quit rates, and greater success is seen with increased frequency of interventions/counseling cessations. The use of pharmacotherapy also was shown to be beneficial.37Miller M, Wood L. Effectiveness of smoking cessation interventions: review of evidence and implications for best practice in Australian health care settings. Aust N Z J Public Health. 2003;27(3):300-9 https://www.ncbi.nlm.nih.gov/pubmed/14705286. Smoking cessation programs can also be effective for adults 50 years of age and older.38Chen D, Wu LT. Smoking cessation interventions for adults aged 50 or older: a systematic review and meta-analysis. Drug Alcohol Depend. 2015;154:14-24 https://www.ncbi.nlm.nih.gov/pubmed/26094185.

Emphasizing smoking cessation is an essential aspect of health promotion that a healthcare professional can provide to their patients who smoke. As noted above, however, even with frequent societal messaging that emphasizes the dangers of smoking and includes information about ways people can access smoking cessation materials, dental professionals are not universally engaged in these activities with their patients. Cigarette smoking is an oral habit, is a major risk factor for oral diseases, and evidence of the effects of smoking are often obvious in the oral cavity. Therefore, oral healthcare professionals are in an ideal position to speak to their patients who smoke about quitting and assist them in doing so.

There are many resources available to providers and patients regarding smoking cessation. Of note, the U.S. Centers for Disease Control and Prevention website (www.cdc.gov/smoking cessation) provides valuable information about how to quit smoking, behavioral and medical resources, and information about quit rates. There is a telephone quit line (1-800-QUIT-NOW; 1-800-784-8669), as well as a text messaging service (Text QUITNOW to 333888). There are also many phone apps that can also be useful (i.e., Flamy, Get Rich or Die Smoking). The U.S. Department of Health and Human Services also offers a user-friendly website (www.smokefree.gov).

Professional health organizations also offer valuable resources, A good example is that available is provided by the American Lung Association (www.lung.org). Their “Freedom from Smoking” program provides answers to frequently asked questions, information about both group and online programs, how to become a smoking cessation facilitator, as well as many other resources. The America Cancer Society (www.cancer.org) offers a wealth of information for patients and providers, and the ‘’Great American Smokeout’ identifies the third Thursday in November as a nation-wide effort for those who want to stop smoking. Furthermore, the American Dental Association (www.ada.org) offers general information about tobacco products and smoking cessation for dental professionals. In addition to reviewing the many ways tobacco is used (including water pipes and forms of smokeless tobacco), there is information about electronic nicotine delivery systems and other forms of pharmacotherapy that can be used as part of a smoking cessation program (see Table 1),

In addition, individual states provide valuable information and services. Two examples are the resources offered by New York and California. New York State Department of Health has a Quitline which can be accessed via phone (1-866-NYQUITS; 1-866-697-8487), text (716-309-4688) or their website (www.nysmokefree.com). California offers information through the California Department of Public Health (www.cdph.ca.gov/programs).

Conclusions

There is no question that smoking cessation should be a fundamental service provided by dental professionals to their patients who smoke or otherwise use tobacco products. Helping a patient quit smoking can be a very rewarding experience for a health care professional. For dental professionals this means decreasing the risk for oral diseases, improving the response to dental treatment (specifically periodontal therapy) while also decreasing the risk for the many systemic diseases associated with smoking. It must also be mentioned that the percentage of people who attempt to quit and succeed is relatively low, as a nicotine habit is difficult to break, so this activity must be approached with realistic expectations. However, every patient who succeeds in quitting is an important victory. Oral healthcare professionals must embrace this responsibility, and both patients and providers will benefit.

Table 1. Pharmacotherapy for the Treatment of Tobacco Dependence


Source: American Dental Association.

References

• 1.Samet JM. Tobacco smoking: the leading cause of preventable disease worldwide. Thorac Surg Clin. 2013;23(2):103-12 https://www.ncbi.nlm.nih.gov/pubmed/23566962.
• 2.Centers for Disease Control and Prevention. Smoking & Tobacco Use. https://www.cdc.gov/tobacco/index.htm. Accessed January 14, 2024.
• 3.Centers for Disease Control and Prevention. Tobacco-Related Mortality. https://archive.cdc.gov/#/details?q=https://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/tobacco_related_mortality/index.htm&start=0&rows=10&url=https://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/tobacco_related_mortality/index.htm. Accessed January 14, 2024.
• 4.Bergstrom J. Tobacco smoking and chronic destructive periodontal disease. Odontology. 2004;92(1):1-8 https://www.ncbi.nlm.nih.gov/pubmed/15490298.
• 5.Leite FRM, et al. Effect of smoking on periodontitis: a systematic review and meta-regression. Am J Prev Med. 2018;54(6):831-41 https://www.ncbi.nlm.nih.gov/pubmed/29656920.
• 6.Aminoshariae A, et al. The association between smoking and periapical periodontitis: a systematic review. Clin Oral Investig. 2020;24(2):533-45 https://www.ncbi.nlm.nih.gov/pubmed/31773370.
• 7.Petersen PE. Oral cancer prevention and control–the approach of the World Health Organization. Oral Oncol. 2009;45(4-5):454-60 https://www.ncbi.nlm.nih.gov/pubmed/18804412.
• 8.Ogden GR. Alcohol and oral cancer. Alcohol. 2005;35(3):169-73 https://www.ncbi.nlm.nih.gov/pubmed/16054978.
• 9.Edirisinghe ST, et al. The risk of oral cancer among different categories of exposure to tobacco smoking in Sri Lanka. Asian Pac J Cancer Prev. 2022;23(9):2929-35 https://www.ncbi.nlm.nih.gov/pubmed/36172654.
• 10.Mariano LC, et al. Secondhand smoke exposure and oral cancer risk: a systematic review and meta-analysis. Tob Control. 2022;31(5):597-607 https://www.ncbi.nlm.nih.gov/pubmed/33903278.
• 11.Giraldi L, et al. Infection with Human Papilloma Virus (HPV) and risk of subsites within the oral cancer. Cancer Epidemiol. 2021;75:102020 https://www.ncbi.nlm.nih.gov/pubmed/34509873.
• 12.Baig MR, Rajan M. Effects of smoking on the outcome of implant treatment: a literature review. Indian J Dent Res. 2007;18(4):190-5 https://www.ncbi.nlm.nih.gov/pubmed/17938497.
• 13.Abt E. Smoking increases dental implant failures and complications. Evid Based Dent. 2009;10(3):79-80 https://www.ncbi.nlm.nih.gov/pubmed/19820742.
• 14.Martinez-Amargant J, et al. Association between smoking and peri-implant diseases: a retrospective study. Clin Oral Implants Res. 2023;34(10):1127-40 https://www.ncbi.nlm.nih.gov/pubmed/37523460.
• 15.Asthana S, et al. Association of smokeless tobacco use and oral cancer: a systematic global review and meta-analysis. Nicotine Tob Res. 2019;21(9):1162-71 https://www.ncbi.nlm.nih.gov/pubmed/29790998.
• 16.Centers for Disease Control and Prevention. Smoking & Tobacco Use. Cigarette Smoking in the U.S. https://www.cdc.gov/tobacco/data_statistics/fact_sheets/fast_facts/cigarette-smoking-in-the-us.html. Accessed January 14, 2024.
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• 18.Lindson N, et al. Strategies to improve smoking cessation rates in primary care. Cochrane Database Syst Rev. 2021;9(9):CD011556 https://www.ncbi.nlm.nih.gov/pubmed/34693994.
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• 20.Sujatha S, et al. Long-term follow-up of tobacco cessation intervention in a dental setting: a randomized trial. J Cancer Res Ther. 2023;19(Supplement):S0 https://www.ncbi.nlm.nih.gov/pubmed/37147945.
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• 22.Nelson JL, et al. Patient-reported receipt of oral cancer screenings and smoking cessation counseling from US oral health care providers: National Health and Nutrition Examination Survey, 2015-2016. J Am Dent Assoc. 2019;150(12):995-1003 https://www.ncbi.nlm.nih.gov/pubmed/31761028.
• 23.Chang J, et al. The impact of smoking on non-surgical periodontal therapy: a systematic review and meta-analysis. J Clin Periodontol. 2021;48(1):60-75 https://www.ncbi.nlm.nih.gov/pubmed/33022758.
• 24.Leite FRM, et al. Effect of smoking exposure on nonsurgical periodontal therapy: 1-year follow-up. J Dent Res. 2023;102(3):280-6 https://www.ncbi.nlm.nih.gov/pubmed/36333874.
• 25.Van der Velden U, et al. Effect of smoking and periodontal treatment on the subgingival microflora. J Clin Periodontol. 2003;30(7):603-10 https://www.ncbi.nlm.nih.gov/pubmed/12834497.
• 26.da Silva RVC, et al. Smoking negatively impacts the clinical, microbiological, and immunological treatment response of young adults with Grade C periodontitis. J Periodontal Res. 2022;57(6):1116-26 https://www.ncbi.nlm.nih.gov/pubmed/36050890.
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