What is not so clear is the effect of smoking on the
gingival health of people not susceptible to periodontal
disease. The research is not conclusive with Gunnsolley et
al. [67] demonstrating a strong association between smoking
and both attachment loss and recession in subjects who have
minimal or no periodontal disease. Other data do not support
the hypothesis that smokers not susceptible to periodontal
disease are at an increased risk for the development of
gingival recession [68]. There is probably a number of
confounding factors to explain these differences in the re-
search outcomes, such as the gingival biotype and oral
hygiene habits; smokers often brushing their teeth over
zealously due to increased staining of the hard tissue [69].