3.11 Dental diseases

Last updated: July 2021
Suggested citation: Winnall, WR, Purcell, K, Greenhalgh, EM & Winstanley, MH. 3.11 Dental diseases. In Greenhalgh, EM, Scollo, MM and Winstanley, MH [editors]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2021. Available from http://www.tobaccoinaustralia.org.au/3-11-dental-diseases

 

The oral cavity is the first part of the anatomy to be exposed to mainstream smoke in people who smoke, or to tobacco in those who chew tobacco. The oral mucosa (lining of the mouth), the teeth and the gingivae (gums) are all quickly affected by tobacco, including by heat from burned tobacco, irritation from the smoke and the effects of the toxic chemicals contained in the smoke.1

Plaque is a build-up of bacteria and food debris, caused by poor oral hygiene. Plaque build-up on the teeth and gums can cause inflammation called gingivitis, an early stage gum disease. If left untreated, gingivitis can lead to an advanced stage gum disease called periodontitis. During periodontitis, the soft and hard tissues that support the teeth, including ligaments and bone, can sustain damage due to this inflammation. Periodontitis may lead to the development of abscesses in soft tissue and bone, a greater risk of decay of the exposed root surfaces of the tooth, loose teeth and tooth loss.2, 3 Smoking and chewing tobacco causes inflammation in the mouth, and therefore play a role in the causation of periodontitis and other oral pathologies.2

Periodontitis, dental caries and peri-implant pathology are three common chronic oral health conditions and smoking is a risk factor for all three. It has been estimated that preventing uptake of smoking could result in a potential reductions of 37% of cases of periodontitis, 7% of dental caries, and 39% of cases of failure of tooth implants.4

A large study in the United Kingdom found that non-smokers were more likely to rate themselves as having 'good oral health' compared with smokers (75% versus 57% respectively).5 Smokers were also twice as likely to attend the dentist symptomatically compared with non-smokers who were more likely to have regular dental visits. Disadvantaged smokers were also more likely to attend the dentist symptomatically and perceive that they had poorer oral health.5

Smoking is a cause of oral cancers, as described in Chapter 3, Section 3.5.1. Smoking may also cause premalignant conditions in the mouth that can give rise to cancer. Collectively these are known Oral Potentially Malignant Disorders (OPMD), and include leukoplakia, erythroplakia and oral submucous fibrosis. Smoking is implicated as a cause of these three conditions, as well as the conversion of the OPMD oral lichen planus into cancer.1

3.11.1 Periodontitis

Periodontitis (gum disease or periodontal disease) is inflammation and damage of the gums, ligaments and bone that support the teeth. As people age, the risk of periodontitis increases.6 Other risk factors include gingivitis, tobacco use and poor oral hygiene.

Periodontitis associated with substantial morbidity and health care costs. Almost 30% of Australian people over the age of 15 have periodontitis.3 Analysis of the Australian National Survey of Adult Health (2004–2006) suggested that about 32% of moderate to severe periodontitis is due to smoking. This extrapolates to an estimated 700,000 Australian adults affected by periodontitis due to their smoking, based on the 2004 to 2006 figures.7

Smoking is a cause of periodontitis.2 A systematic review and meta-analysis of six studies in 2017 found that current smoking increased the risk of developing periodontitis by 80% compared with ex-smokers and never smokers.8 A 2018 meta-analysis of 14 prospective longitudinal studies found that smoking is related to both the incidence and progression of periodontitis.9 An estimated 14% of periodontitis is attributable to smoking.9 Smokers also experience greater severity10 and a more rapid progression of periodontal disease than non-smokers.8, 10

In people who smoke with periodontitis, there are increases in the number of teeth affected and the number of sites affected in the mouth, compared to never smokers with the condition.11 Smokers have a poorer response to periodontal therapy than non-smokers.8, 10, 12, 13

The precise means by which smoking causes periodontitis have not been determined, but several mechanisms have been proposed. First, smoking may increase the quantity of plaque and the likelihood that bacterial pathogens colonise the plaque. Second, smoking impairs the body’s immune response, making the smoker more susceptible to bacterial infection and also impairing the regeneration and repair of periodontal tissues. Third, the vasoconstrictive effect of tobacco smoke and nicotine may reduce gingival blood flow and impair oxygen and nutrient delivery to gingival tissue.2 Smoking can also result in oxidative stress and changes to the immunoinflammatory processes that may also play an important role in the development of periodontitis.10

The oral microflora refers to all of the microorganisms (hundreds of species of bacteria) that naturally reside in the mouth of a person. Alterations in the oral microbiota induced by smoking may be responsible for the role of smoking in periodontitis.14 Early studies in this field found inconsistencies, with some studies finding differences between the bacteria species present in smokers with periodontitis, and other studies finding no differences.15 More recently, techniques that detected a much broader range of bacteria have shown that consistent alterations exist in the range oral microflora of smokers with periodontitis16 as well as gingivitis,17 compared to non-smokers with these conditions. More studies are necessary to determine whether these changes are part of the mechanism by which smoking causes periodontitis and other dental conditions.15

Use of tobacco in other forms is likely to be increasing the risk of periodontitis. People who use smokeless tobacco, which is chewed, may have a higher chance of periodontal inflammation including gingivitis, gingival recession and periodontal pocketing.18 Chewing tobacco is at least as harmful, perhaps even more so than smoking. In one study, those with periodontitis who chewed tobacco had a higher number of bleeding sites, more periodontal pockets and more sites with tooth attachment loss.19

Smoking also results in poorer bone regeneration after surgical treatment aimed at replacing all missing tissues of the periodontium. A 2011 meta-analysis found significantly less bone gain in smokers than non-smokers after such treatment.20 Smoking also appears to inhibit the healing process following periodontal treatment by impacting on periodontal ligament stem cells.21

Those who had quit smoking had a similar risk of periodontitis to never smokers,8 and a lower risk of disease progression than those who continue to smoke.10, 22 Smoking cessation is also associated with improved non-surgical periodontal treatment outcomes.8 The balance of bacteria in the mouth may be restored by sustained smoking cessation. One study has shown that former smokers had no difference in the balance of bacterial species compared to non-smokers, indicating that the balance of bacteria in the mouth may have been restored after cessation.14 This may be one mechanism behind the improvements in periodontitis risk in former smokers, but further research is necessary to investigate this possibility.

3.11.2 Dental caries

Dental caries (cavities) occur when acids produced by bacteria dissolve the hard enamel of the tooth surface. It is then possible for bacteria to penetrate the tooth and reach the pulp tissue, potentially resulting in pain, infection and the need for tooth extraction.2 Evidence suggests that smoking promotes the growth of bacterial microorganisms in the mouth that increase the risk of dental caries.14 The presence of nicotine enhances the growth of some of these bacteria, and smoking behaviour also influences the components of saliva. Together these changes promote an environment that makes smokers more susceptible to the formation of caries.14

The 2014 US Surgeon General’s report found that smokers are more likely to have dental caries, missing teeth due to decay, or fillings, although more research is needed to establish smoking as a cause.23 Data from a US National Health and Nutrition survey of more than 5,000 women published in 2009 found that smoking is a risk factor for untreated caries and decayed, missing and filled permanent tooth surfaces.24 A 2019 systematic review and meta-analysis of eleven studies also found a positive association between tobacco smoking and dental caries.25 A 2019 prospective observational study of young adults in Sweden found that smoking, but not the use of moist Swedish snuff, showed a significant relationship with development of dental caries over a three year period.26 A study from India showed that people who chew tobacco were also at risk of dental caries.27

3.11.3 Tooth loss

The main biological causes of tooth loss (edentulism) are periodontal disease and caries.28 As outlined above, smoking is associated with both.

There is a strong association between smoking and tooth loss.29-31 A 2011 systematic review,32 a 2015 large cohort study in Germany,28 and a 2018 meta-analysis all found that smokers were more likely to experience tooth loss compared with non-smokers.29 Two Japanese studies also found that smoking was associated with the number of missing teeth.33, 34 A study from Pakistan found that users of smokeless tobacco had an increased risk of tooth loss compared to people who did not use tobacco.35

The Australian ‘45 and Up Study’ investigated the association between smoking and the chance of being edentulous (having no teeth remaining) in approximately 100,000 residents of New South Wales. Smokers had a 2.5-fold higher risk of being edentulous compared with never smokers.36

Most studies report that the duration and intensity of smoking are important factors influencing the risk of tooth loss.28-31, 36 Ten years or more of smoking is associated with tooth loss and this effect appears to be strongest among men who are current smokers and weakest among women who were ex-smokers.37 There is a dose response relationship, with heavy smoking (>15 cigarettes per day) associated with a three times higher risk of tooth loss in men and more than twice the tooth loss in women younger than 50 years of age compared with never smokers.28

The relationship between smoking and tooth loss is apparent even among adults who have had access to subsidised dental care during their lifetime.31 A 2015 cohort study in Finland of almost 2,000 adults found a clear relationship between the intensity and the duration of smoking and tooth loss, even with access to subsidised dental care and self-reported good oral health.31

Sustained smoking cessation is associated with a reduction in tooth loss.28, 30, 38 Some studies have reported that the risk of tooth loss in a smoker will approximate that of a never smoker (depending on age and gender) after ten years,28, 37 while others report a reduction in this risk after twenty years or more of cessation.30, 33 The Australian ‘45 and up study’ found that the risk of being edentulous was still higher than that of never smokers 30 years after quitting.36

3.11.4 Complications and failure of dental procedures

Due to the established adverse effects of smoking on the oral cavity, researchers have investigated the impact of smoking on the outcome of surgical procedures for periodontal disease39 and the success of prosthetic implants for missing teeth40 and other dental procedures.

Smokers appear to have an increased risk of implant failure compared with non-smokers following dental implant procedures.41-44 A 2007 meta-analysis of 29 studies found a higher risk of implant failures and complications in smokers compared with non-smokers.40 A 2015 meta-analysis examined 19,836 implants placed in smokers and 60,464 implants placed in non-smokers.45 There was a failure rate of 6.35% in smokers (1259 failures) and 3.18 % failure in non-smokers (1923 failures).45 A meta-analysis from 2020 showed that the risk of implant failure was higher for people who smoked a greater number of cigarettes per day.44 Smokers also have a greater risk of marginal bone loss42, 45, 46 and higher rate of postoperative infections following implant procedures.45, 47 There was a greater degree of marginal bone loss around implants47 and implant failure48 for people who smoked for longer duration or a higher number of cigarettes per day.

Cigarette smoke can also cause significant discoloration of dental composite resins used for dental restoration.49 A 2009 meta-analysis of seven studies found that root-coverage procedures for people with periodontal disease were less successful in smokers than non-smokers.39 Smoking may also be associated with poor outcomes for root canal treatment.50

A 2019 retrospective clinical study found that waterpipe users, as well as smokers, are vulnerable to peri-implant soft tissue inflammation and bone loss following dental implant procedures, compared with those who have never smoked.51

Advice from dentists about quitting can be effective in encouraging quit attempts among smokers and may have benefits in reaching smokers who may not be in regular contact with other parts of the health system52 —refer Chapter 7, Section 7.10.4 for further details. 

3.11.5 Other dental conditions

Smoking has a negative effect on the quality of saliva in a long term smokers’ mouth. The saliva of smokers is thicker than non-smokers and the amount of saliva decreases significantly with long-term smoking and increasing age.53 Smokers also had a lower (more acidic) salivary pH compared with non-smokers which may make them more susceptible to oral and dental disease.54 Long-term smokers often have poorer oral hygiene compared with never smokers, which compounds the problem.53

Smokers with dental diseases are more likely to experience orofacial pain. A systematic review of eight studies showed that people with oral diseases who were smokers had three times the odds of experiencing orofacial pain compared to non-smoking patients.55


Relevant news and research

For recent news items and research on this topic, click  here. ( Last updated August 2021)


References 

1.   Ford PJ and Rich AM. Tobacco use and oral health. Addiction, 2021. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33822437

2.   US Department of Health and Human Services. The health consequences of smoking: a report of the Surgeon General. Atlanta, Georgia: US Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2004. Available from: http://www.cdc.gov/tobacco/data_statistics/sgr/index.htm.

3.   Australian Institute for Health and Welfare. Oral health and dental care in Australia. Canberra, Australia: AIHW, 2020. Available from: https://www.aihw.gov.au/reports/den/231/oral-health-and-dental-care-in-australia/contents/healthy-mouths.

4.   de Araujo Nobre M and Malo P. Prevalence of periodontitis, dental caries, and peri-implant pathology and their relation with systemic status and smoking habits: Results of an open-cohort study with 22009 patients in a private rehabilitation center. Journal of Dentistry, 2017; 67:36-42. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28750777

5.   Csikar J, Kang J, Wyborn C, Dyer TA, Marshman Z, et al. The self-reported oral health status and dental attendance of smokers and non-smokers in England. PLoS ONE, 2016; 11(2):e0148700. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26863107

6.   Australian Institute for Health and Welfare. Oral health and dental care in Australia 2015. Canberra, Australia: AIHW, 2015. Available from: https://www.aihw.gov.au/reports/dental-oral-health/oral-health-and-dental-care-in-australia-2015/contents/oral-health-in-australia.

7.   Do LG, Slade GD, Roberts-Thomson KF, and Sanders AE. Smoking-attributable periodontal disease in the Australian adult population. Journal of Clinical Periodontology, 2008; 35(5):398-404. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18433383

8.   Leite FRM, Nascimento GG, Baake S, Pedersen LD, Scheutz F, et al. Impact of smoking cessation on periodontitis: A Systematic Review and Meta-analysis of Prospective Longitudinal Observational and Interventional Studies. Nicotine and Tobacco Research, 2019; 21(12):1600-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30011036

9.   Leite FRM, Nascimento GG, Scheutz F, and Lopez R. Effect of smoking on periodontitis: A systematic review and meta-regression. American Journal of Preventive Medicine, 2018; 54(6):831-41. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29656920

10. Nociti FH, Jr., Casati MZ, and Duarte PM. Current perspective of the impact of smoking on the progression and treatment of periodontitis. Periodontology 2000, 2015; 67(1):187-210. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25494601

11. Billings M, Parascandola M, Iafolla T, and Dye BA. Data visualization of the relationship between smoking and periodontal site-specific effects across the lifespan in the U.S. adult population. Journal of Periodontology, 2020. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33251598

12. Boulaamaim T, Tenenbaum H, Davideau JL, and Huck O. Selective influence of smoking on periodontal treatment outcomes after 3 years of follow-up. Oral Health and Preventive Dentistry, 2020; 18(1):823-31. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32895667

13. Chang J, Meng HW, Lalla E, and Lee CT. The impact of smoking on non-surgical periodontal therapy: A systematic review and meta-analysis. Journal of Clinical Periodontology, 2021; 48(1):60-75. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33022758

14. Wu J, Li M, and Huang R. The effect of smoking on caries-related microorganisms. Tob Induced Diseases, 2019; 17:32. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31516475

15. Jiang Y, Zhou X, Cheng L, and Li M. The impact of smoking on subgingival microflora: From periodontal health to disease. Frontiers in Microbiology, 2020; 11:66. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32063898

16. Bizzarro S, Loos BG, Laine ML, Crielaard W, and Zaura E. Subgingival microbiome in smokers and non-smokers in periodontitis: an exploratory study using traditional targeted techniques and a next-generation sequencing. Journal of Clinical Periodontology, 2013; 40(5):483-92. Available from: https://www.ncbi.nlm.nih.gov/pubmed/23489056

17. Joshi V, Matthews C, Aspiras M, de Jager M, Ward M, et al. Smoking decreases structural and functional resilience in the subgingival ecosystem. Journal of Clinical Periodontology, 2014; 41(11):1037-47. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25139209

18. Muthukrishnan A and Warnakulasuriya S. Oral health consequences of smokeless tobacco use. Indian Journal of Medical Research, 2018; 148(1):35-40. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30264752

19. Yaragani A, Sushuma K, Guduri V, Thirumalasetty S, Vishnubhotla G, et al. The influence of tobacco consumption on periodontal health: A stratified analysis based on type of tobacco use. Journal of Family Medicine and Primary Care, 2020; 9(4):2061-6. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32670966

20. Patel RA, Wilson RF, and Palmer RM. The effect of smoking on periodontal bone regeneration: a systematic review and meta-analysis. Journal of Periodontology, 2012; 83(2):143-55. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21627463

21. Ng TK, Huang L, Cao D, Yip YW, Tsang WM, et al. Cigarette smoking hinders human periodontal ligament-derived stem cell proliferation, migration and differentiation potentials. Scientific Reports, 2015; 5:7828. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25591783

22. Gugnani N and Gugnani S. Can smoking cessation impact the incidence and progression of periodontitis? Evidence-based Dentistry, 2020; 21(4):122-3. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33339968

23. US Department of Health and Human Services. The Health Consequences of Smoking: 50 Years of Progress. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014. Available from: https://www.ncbi.nlm.nih.gov/books/NBK179276/pdf/Bookshelf_NBK179276.pdf.

24. Iida H, Kumar JV, Kopycka-Kedzierawski DT, and Billings RJ. Effect of tobacco smoke on the oral health of US women of childbearing age. Journal of Public Health Dentistry, 2009; 69(4):231–41. Available from: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1752-7325.2009.00128.x

25. Jiang X, Jiang X, Wang Y, and Huang R. Correlation between tobacco smoking and dental caries: A systematic review and meta-analysis. Tobacco Induced Diseases, 2019; 17:34. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31516477

26. Petersson GH and Twetman S. Tobacco use and caries increment in young adults: a prospective observational study. BMC Research Notes, 2019; 12(1):218. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30971314

27. Mittal N, Singh N, and Naveen Kumar PG. Prevalence of dental caries among smoking and smokeless tobacco users attending dental hospital in eastern region of Uttar Pradesh. Indian Journal of Community Medicine, 2020; 45(2):209-14. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32905180

28. Dietrich T, Walter C, Oluwagbemigun K, Bergmann M, Pischon T, et al. Smoking, smoking cessation, and risk of tooth loss: The EPIC-Potsdam Study. Journal of Dental Research, 2015; 94(10):1369-75. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26243734

29. Vieira TR, Martins CC, Cyrino RM, Azevedo AMO, Cota LOM, et al. Effects of smoking on tooth loss among individuals under periodontal maintenance therapy: a systematic review and meta-analysis. Cadernos de Saude Publica, 2018; 34(9):e00024918. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30281706

30. Carson SJ and Burns J. Impact of smoking on tooth loss in adults. Evidence-based Dentistry, 2016; 17(3):73-4. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27767106

31. Simila T and Virtanen JI. Association between smoking intensity and duration and tooth loss among Finnish middle-aged adults: The Northern Finland Birth Cohort 1966 Project. BMC Public Health, 2015; 15(1):1141. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26576994

32. Hanioka T, Ojima M, Tanaka K, Matsuo K, Sato F, et al. Causal assessment of smoking and tooth loss: a systematic review of observational studies. BMC Public Health, 2011; 11(1):221. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21477320

33. Yanagisawa T, Marugame T, Ohara S, Inoue M, Tsugane S, et al. Relationship of smoking and smoking cessation with number of teeth present: JPHC Oral Health Study*. Oral Diseases, 2009; 15(1):69-75. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18761641

34. Yanagisawa T, Ueno M, Shinada K, Ohara S, Wright FA, et al. Relationship of smoking and smoking cessation with oral health status in Japanese men. Journal of Periodontal Research, 2010; 45(2):277-83. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19744265

35. Qureshi FH, Hamid S, Khan SM, and Qureshi AH. Effect of tobacco use on tooth loss among patients visiting the out-patient dental department of a tertiary care hospital in Pakistan. Journal Of Pakistan Medical Association, 2018; 68(6):841-7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29887612

36. Arora M, Schwarz E, Sivaneswaran S, and Banks E. Cigarette smoking and tooth loss in a cohort of older Australians: the 45 and up study. Journal of the American Dental Association, 2010; 141(10):1242-9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/20884927

37. Simila T, Auvinen J, Timonen M, and Virtanen JI. Long-term effects of smoking on tooth loss after cessation among middle-aged Finnish adults: the Northern Finland Birth Cohort 1966 Study. BMC Public Health, 2016; 16(1):867. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27557640

38. Al-Ansari A. Smoking cessation is effective in reducing the risk of tooth loss. Evidence-based Dentistry, 2020; 21(4):120-1. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33339967

39. Chambrone L, Chambrone D, Pustiglioni FE, Chambrone LA, and Lima LA. The influence of tobacco smoking on the outcomes achieved by root-coverage procedures: a systematic review. Journal of the American Dental Association, 2009; 140(3):294-306. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19255173

40. Strietzel FP, Reichart PA, Kale A, Kulkarni M, Wegner B, et al. Smoking interferes with the prognosis of dental implant treatment: a systematic review and meta-analysis. Journal of Clinical Periodontology, 2007; 34(6):523-44. Available from: https://www.ncbi.nlm.nih.gov/pubmed/17509093

41. Veitz-Keenan A. Marginal bone loss and dental implant failure may be increased in smokers. Evidence-based Dentistry, 2016; 17(1):6-7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27012565

42. Alfadda SA. Current evidence on dental implants outcomes in smokers and nonsmokers: A systematic review and meta-analysis. Journal of Oral Implantology, 2018; 44(5):390-9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29864381

43. Badenes-Catalan J and Pallares-Sabater A. Influence of smoking on dental implant osseointegration: A radiofrequency analysis of 194 implants. Journal of Oral Implantology, 2021; 47(2):110-7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32699886

44. Naseri R, Yaghini J, and Feizi A. Levels of smoking and dental implants failure: A systematic review and meta-analysis. Journal of Clinical Periodontology, 2020; 47(4):518-28. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31955453

45. Chrcanovic BR, Albrektsson T, and Wennerberg A. Smoking and dental implants: A systematic review and meta-analysis. Journal of Dentistry, 2015; 43(5):487-98. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25778741

46. Mumcu E and Dayan SC. Effect of smoking and locations of dental implants on peri-implant parameters: 3-year follow-up. Medical Science Monitor, 2019; 25:6104-9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31414668

47. Nazeer J, Singh R, Suri P, Mouneshkumar CD, Bhardwaj S, et al. Evaluation of marginal bone loss around dental implants in cigarette smokers and nonsmokers. A comparative study. Journal of Family Medicine and Primary Care, 2020; 9(2):729-34. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32318410

48. Devlin AC and Fee PA. How do different levels of smoking affect dental implants? Evidence-based Dentistry, 2021; 22(1):28-9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33772129

49. Zhao X, Zanetti F, Majeed S, Pan J, Malmstrom H, et al. Effects of cigarette smoking on color stability of dental resin composites. American Journal of Dentistry, 2017; 30(6):316-22. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29251454

50. Cabanillas-Balsera D, Segura-Egea JJ, Jimenez-Sanchez MC, Areal-Quecuty V, Sanchez-Dominguez B, et al. Cigarette smoking and root filled teeth extraction: Systematic review and meta-analysis. Journal of Clinical Medicine, 2020; 9(10). Available from: https://www.ncbi.nlm.nih.gov/pubmed/33008023

51. Alahmari F, Javed F, Ahmed ZU, Romanos GE, and Al-Kheraif AA. Soft tissue status and crestal bone loss around conventionally-loaded dental implants placed in cigarette- and waterpipe (narghile) smokers: 8-years' follow-up results. Clinical Implant Dentistry and Related Research, 2019; 21(5):873-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30884091

52. Ordell S and Ekback G. Smoking cessation and associated dental factors in a cohort of smokers born in 1942: 5 year follow up. International Dental Journal, 2019; 69(2):107-12. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30009445

53. Petrusic N, Posavac M, Sabol I, and Mravak-Stipetic M. The effect of tobacco smoking on salivation. Acta Stomatologica Croatica, 2015; 49(4):309-15. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27688415

54. Grover N, Sharma J, Sengupta S, Singh S, Singh N, et al. Long-term effect of tobacco on unstimulated salivary pH. Journal of Oral and Maxillofacial Pathology, 2016; 20(1):16-9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27194856

55. Alamir AH and Quadri MFA. Tobacco use and orofacial pain: A meta-analysis. Nicotine and Tobacco Research, 2020; 22(11):1957-63. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32374841