Final answer:
Smoking is the systemic and environmental risk factor that has a higher influence on periodontal disease progression than periodontal pathogens, due to its substantial effect on the severity of gum inflammation and tooth loss.
Step-by-step explanation:
Among the systemic and environmental risk factors for periodontal disease progression, smoking is thought to have more influence than periodontal pathogens. Smoking not only causes oral problems like periodontitis but also contributes to a higher risk of tooth loss compared to non-smokers. It is recognized as a prominent environmental risk factor not only for periodontal disease but also for cardiovascular diseases and type 2 diabetes, closely associated with metabolic syndrome, which includes obesity, high blood pressure, and high blood glucose levels. Additionally, diabetes is a systemic condition that greatly increases periodontal risk, illustrating the connection between systemic health and oral health. Whereas poor oral hygiene and genetics indeed play roles in periodontal disease progression, the direct impact of smoking on the gums is more critical, resulting in an increased severity of inflammation and a higher incidence of advanced periodontitis. This makes smoking cessation an important aspect of periodontal treatment and prevention strategies.
Therefore, d) Smoking is the final answer to the question, with its substantial effect on both gum inflammation and tooth loss. This is concluded in a two line explanation: Smoking incurs significant oral health risks, notably causing periodontitis and increasing the likelihood of tooth loss, proving to be a more influential risk factor than periodontal pathogens.