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Smoking and its impact on periodontal health

Smoking results in an increased susceptibility to periodontitis and poorer response to gum treatment. Read further to understand the impact and how you can address this with your patients.

Smoking and its impact on periodontal health

Role of tobacco on oral health

Cigarette smoking is one of the major cause of a variety of human diseases. Cigarettes contain over 3800 chemicals, including carbon monoxide, hydrogen cyanide, and reactive oxidizing radicals, and sixty of these chemicals are known or suspected to be carcinogenic. These chemicals and have a major effect on body functions and are the cause for a variety of pathological conditions.1,2

A meta-analysis of data from six such studies involving 2361 individuals indicated that current smokers had 3-fold higher risk of developing severe periodontitis than non-smokers. Smoking has a localized effect on the mouth. This is evident from the marked difference between smokers and non-smokers in probing depths or attachment loss which occurs in the maxillary lingual area and mandibular anterior teeth. 1,2

Impact of smoking on periodontal disease

The impact of tobacco on the periodontal tissues depends on the frequency and duration of smoking. Periodontal diseases due to smoking show more predilection for males. Smoking is an independent risk factor for the initiation, extent, and severity of the periodontal disease. It can also lower the chances for successful treatment3,4

smoking infographics

Figure 1: Mechanisms by which smoking affects periodontal disease

Effects of smoking on exocrine glands

Many studies have reported that there is a marked increase in parotid flow rate has been reported following smoking a cigarette. This results in an increased flow rate of saliva.4,5                          

The initial salivation created by smoking is possibly caused by smoke irritation and the acidity due to cigarette smoke. 4,5

  • This change of the salivary flow or microflora may be accountable for the increased prevalence of calculus in smokers. 4
  • The vasoconstriction of peripheral blood vessels which is caused by smoking can also affect the periodontal tissue as smokers have less overt signs of gingivitis than non-smokers. 4
Figure 2: Microbial status in the oral cavity in smokers

Figure 2: Microbial status in the oral cavity in smokers

Smoking and its effect on the subgingival microflora

Cigarette smoking can reduce the oxidation-reduction potential (Eh), which can cause an increase in anaerobic plaque bacteria. The result from several studies shows that Eh values in gingiva drop significantly after smoking one cigarette. Also, tobacco smoke contains phenols and cyanides which can account for antibacterial and toxic properties which in turn significantly increases the risk of infection.4

Bacterias like P. gingivalis is also more likely to sub gingivally infect smokers than non-smokers. It has been found that three species of Gram-negative bacteria- Branhamella catarrhalis, Neisseria perflava, and Neisseria sicca are more susceptible to cigarette smoke than three species of Gram-positive bacteria Streptococcus mitis, Streptococcus salivarius, and Streptococcus sanguinis.4

Local effects of nicotine in the oral cavity

The oral tissues of smokers are exposed to high nicotine concentrations that negatively affect local cell populations.6

  • Smoking impairs revascularization during soft and hard tissue wound healing.
  • Nicotine binds to root surface in smokers, and In vitro studies show it can alter fibroblast attachment and integrin expression and decrease collagen production while increasing collagenase production.
  • Root surfaces of teeth extracted from smokers show reduced periodontal ligament (PDL) fibroblast attachment as compared to those from non-smokers.
  • Cultured gingival keratinocytes and fibroblasts exposed to nicotine produce higher amounts of the proinflammatory cytokines IL-1 and IL-6, respectively.

Impact of smoking on periodontal therapy

Periodontal diseases caused due to smoking have a significant impact on the body’s immune system and wound healing process. This results in the decreased effect of pharmacological therapy and prolongation of the infection.1

  • In a study were patients who were smokers underwent scaling and root planning, it was seen that patients showed less improvement compared to non-smokers. 1
  • 12 months after undergoing a pocket reduction procedure, patients who are smokers showed a significantly higher percentage of residual pockets. 1
  • Smokers showed less probing pocket depth (PPD) reduction in sites with initial PPD ≥5 mm9
  • Several studies showed that following non-surgical and surgical therapy, probing depth reduction and clinical attachment level improvement in smokers are 50%–75% higher than those of non-smokers.1
  • Patients taking antimicrobials for periodontal diseases there was a greater difference between the control and experimental treatments within smokers as compared to within non-smokers.1

Effects of smoking on the immune system

Smoking causes increased blood leukocytes, neutrophils, lymphocytes, and monocytes, as well as increased hematocrit, haemoglobin, and mean corpuscular volume.7

  • Th17 cell is actively involved in worsening smoking-associated inflammation and autoimmune diseases
  • Smokeless tobacco extracts affect monocyte and oral keratinocyte production of inflammatory mediators which may play a role in the development of these localized tissue alterations
  • Negatively affects phagocytosis, superoxide and hydrogen peroxide generation, integrin expression and protease inhibitor production
  • It also decreases salivary IgA and serum IgG
Figure 3: Effect of smoking on the immune system8

Figure 3: Effect of smoking on the immune system8

effects of smoking diagram

Impairment of the immune system makes the body vulnerable to infection. Thus smoking develops into a vicious cycle but altering the immune response and worsening the periodontal disease.8

 

Benefits of Smoking Cessation on the Periodontium and Periodontal Treatment Outcomes

The periodontal status of a former smoker is intermediate to that of current smokers or non-smoker and appears to be usually closer to that of non-smokers.10 The benefits of smoking cessation on periodontium are likely to be mediated through various pathways such as 10

  1. Shift towards a less pathogenic microflora
  2. Recovery of gingival micro-circulation
  3. Improvement in aspects of the immune-inflammatory responses
  • Several studies reported an increase in gingival blood flow after smoking cessation, as observed with Laser Doppler flowmetry. 10
  • There was an increase of CD8+ T-cells and a decrease of the CD4+/CD8+ within 6 months after smoking cessation. 10
  • It takes more than 8 weeks for levels of IL-1β, IL-8, TNF-α and VEGF to return to their normal values10
  • 6 weeks after quitting smoking there was a ~28% decrease in the number/mean proportion of tooth sites with plaque.11

Conclusion

Smoking interacts with the host and the bacterial challenge, resulting in an increased susceptibility to periodontitis and poorer response to treatment. Recent guidance suggest that dental practices should assess the smoking status of patients and motivate smokers towards quitting.

Tips for managing patients who are trying to quit smoking

The dental practitioner has an edge in helping their patients commit to a smoking cessation program as they may visit their dentist on a more regular basis and therefore have the opportunity to receive repeated educational and personal demonstrations of the effects of tobacco use on their oral health. The dental practitioner may thus be able to employ one or more of the following three strategies:

  • Keeping their patients from initiating use of tobacco products
  • Helping patients to quit through a sustained tobacco cessation program that can be initiated in the clinical setting
  • Addressing the damage to the periodontal support and reducing further damage from tobacco use for those patients, where long-term tobacco cessation has yet to be achieved
  • Advising they to brush twice a day and floss atleast once a day.
  • Recommending a clinically proven toothpaste with antibacterial/antiplaque actives such as zinc can also help in reduceing plaque levels and gingivitis.

 

Reference

  1. Chahal G, et al. Smoking and its effect on periodontium – Revisited. Indian Journal of Dental Sciences. 2017;9(1):44.
  2. Jiang Y, et al. The Impact of Smoking on Subgingival Microflora: From Periodontal Health to Disease. Frontiers in Microbiology. 2020;11.
  3. Zee K, et al. Smoking and periodontal disease. Australian Dental Journal. 2009;54:S44-S50.
  4. Shah A, et al. Periodontal disease and smoking: An overview. Clinical Cancer Investigation Journal. 2016;5(2):99.
  5. Olsson P, et al. Smoking, disease characteristics and serum cytokine levels in patients with primary Sjögren’s syndrome. Rheumatology International. 2018;38(8):1503-1510.
  6. Malhotra R, et al. Nicotine and periodontal tissues. Journal of Indian Society of Periodontology. 2010;14(1):72.
  7. Pedersen KM, et al. Smoking and Increased White and Red Blood Cells. Arterioscler Thromb Vasc Biol. 2019 05;39(5):965-77.
  8. Qiu F, et al. Impacts of cigarette smoking on immune responsiveness: Up and down or upside down?. Oncotarget. 2016;8(1):268-284.
  9. Wan CP, et al. Effects of smoking on healing response to non‑surgical periodontal therapy: A multilevel modelling analysis. Journal of Clinical Periodontology 2009;36:229‑39.
  10. César Neto J, et al. Smoking and periodontal tissues: a review. Brazilian Oral Research. 2012;26(spe1):25-31.
  11. Nair P, et al. Gingival bleeding on probing increases after quitting smoking. J Clin Periodontol. 2003 May;30(5):435-7.

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