It may be in a reputable journal, that doesn't make it a reputable study.
The authors state that the damage to gum cells is due to the flavourings in ecigs, yet they don't use a flavourless eliquid control. Reading through it appears they believe the tobacco flavour is unflavoured!
On a very very basic level this study does not show what it claims. In the press release we get “We learned that the flavorings–some more than others--made the damage to the cells even worse,”
No they really didn't learn that because there was no unflavoured control.
Neither do the authors mention the fact that the flavourings in eliquid are all food flavourings. One of the flavours used is menthol ffs! Nobody suck peppermints!
They use a very old fashioned device and push it quite hard on a machine made to replicate smoking, not vaping. They are likely to be burning the atomiser and producing dry hits, as we have seen in previous useless studies, also published in reputable journals.
Throughout the study, the authors confuse and conflate vaping and smoking, for example:
'Electronic-cigarettes (e-cigs) represent a significant and increasing proportion of tobacco product consumption' - eliquid contains no tobacco, they are not a tobacco product any more than NRT is.
e-cig aerosols compared to conventional cigarette smoke - this study does not compare the two.
Conventional cigarette smoke has been shown to cause deleterious effects on oral and periodontal health [10]. However, the role of e-cig vaping and its association with carbonyl stress, inflammation, and DNA damage-triggered senescence on oral/periodontal epithelium remains unknown. - what thought process went into even comparing the two when the only thing they have in common really is nicotine content?
We have recently shown oxidants/ROS reactivity from e-cig aerosols is comparable to conventional cigarette smoke - yeah they burnt the atomisers that time too.
and from the press release: We showed that when the vapors from an e-cigarette are burned - possibly not inaccurate given their methodology
and How much and how often someone is smoking e-cigarettes will determine the extent of damage to the gums and oral cavity
There's a big para in the introduction of the study about the harms of smoking on gum health. The authors conclude, This most likely occurs as a result of the vasoconstrictive effect of nicotine (nicotine is the main component in e-cigs) on gingival blood vessels.
This is total bollocks, as anyone with gum disease who has quit smoking using either ecigs or oral NRT knows - as soon as you stop smoking your gums bleed like a stuck pig. As far as I can tell, as a well-informed lay-person, the masking effect of smoking on gum disease is because the constituents of smoke kill off your peripheral blood capillaries and once you stop they start regenerating. Nicotine is a vasoconstricter but it has that effect acutely and not chronically. Its effects are remarkably similar to caffeine in this regard.
The other control not used in this experiment is a comparison with the effects of smoking (this is different from the confusion and conflation I talked about above). We know that vapers are almost all still smoking or ex-smokers so it would have been useful to see how these results compared with the harm from smoking. There is nothing in this study that provides a useful comparison. Instead, we have something like 'we know smoking makes your teeth fall out, we've done a study on ecigs and ...'
may pose an oral health concern
may contribute to the pathogenesis of oral diseases
Well how much of a concern? How much does it contribute? Compared to what? Alarmingly, this bobbins gets reported in the mainstream press as Electronic cigarettes are as equally damaging to gums and teeth as conventional cigarettes with no evidence to back that up at all.
Personally I don't give a fuck about some cell study that maybe shows some sort of harm to gums on the possible level of minty NRT lozenges. I'm more concerned about my lungs and heart. I've already smoked my teeth out and am looking forward to my nice plastic set I'm treating myself to for my 50th. I am unlikely to die a decade early from plastic teeth 
Smashing to talk with you again though, theymademejoin, although I have to say I've lost a lot of respect for you for plugging this study which is so shockingly bad even I as a layperson can see it. I thought you were an actual scientist. Clearly not if you can't see the glaring holes in this study.
They are advocating vaping as an alternative to smoking tobacco as there are no longitudinal studies done yet and the current research suggests vaping is less damaging to smokers than tobacco, and that is cheaper to the public purse.
People being healthier costs the public purse less shocker! (actually it doesn't but that's another thread). I don't give a shit really if PH don't care about me personally. They didn't invent vaping, vapers did. They took a long time to come round to idea that there are PH wins to be had from endorsing vaping.
I don't have the time or energy to get into another argument with you about the PHE report. We've done that here if anybody wants to read a sad spiralling debate which ended with a lot of nitpicking about the exact meaning of the word 'endorse'.
Off on hols for a week now so won't be back.