It would be useful, and instructive to the public who have reservations about cannabis consumption that the parameters of low, moderate and heavy use were indicated.
There are some who believe bogarting a joint is 'too much' ;-)
as it indicates a propensity to need to smoke more than socially 'fair', there are some who will smoke in private away from that 'communal' setting we all know so well.... again indicating a need or propensity 'for more'. This moves through the set and setting spectrum where illegal status means consumption 'to dispose of evidence' through to levels where heavy use is defined as 'more than' ten thousand joints over five years as the threshold under which consumption is just moderate.
Each has its own parameters... ranging from 'getting out to lunch' occasionally or more, to occasional in social (and often safe) settings or for some 'topping up' moderately throughout the day.
I suspect the peredontal downside is deserving of more research around the mode of use and set and setting. The gold standard NZ studies (there are two, one longitudinal and one multidisciplinary) are conducted in a context of a heavily enforced prohibition against which four out of five childbearing age adults in the study have used cannabis illegally more than five times.
The illegal status itself leads to significant downsides in outcomes, both mentally, socially and physically. Clearly, there is more to be learned but to discuss health outcomes from this body of research without stating that this research is from a cohort that endures a social set that fosters paranoia, overt and covert prejudice, penalisation, corruption and mistrust is disingenuous if not perverse.
I, along with other researchers (and consumers) argue that whatever downsides do exist they are offset by displacement of other more harmful activities/ingestable's.
Alcohol manufacturers, distributors, marketers and oversight bodies such as ALAC know this. The medical professions reservations about cannabis are at odds with the social burden Alcohol alone contributes.
for more info see https://cannabisnow.com/study-lifelong-marijuana-users-prove-healthy/