Apologies if I misunderstood something about your question.
I will try to answer.
There are various different causes and levels of severity of dry mouth.
If you have dry mouth from simple dehydration, or from electrolyte imbalance due to too much exercise for example, the dry mouth is quite transient and can be alleviated by drinking water. So it goes away quickly.
However, if you have a dry mouth due to a systemic illness (like Sjoren's syndrome, or anxiety disorder or HIV, or some kind of salivary gland dysfunction), then the dry mouth is there persistently 24 hours a day, every day. It constantly causes irritation of your mucous membranes inside the mouth.
When that happens, drinking water is not enough because it only temporarily wets the mouth.
Moreover, saliva contains various natural antimicrobial properties so artificlly replacing the saliva by just wetting the mouth isn't really curing the problem.
What I'm trying to figure out here is the common factor between various types of known patient population groups who suffer from Exfoliative
I want to focus on what we know for sure, from independently verified research, to come to a hypothesis or conclusion.
We know for sure because it is verified in independent research that Sjoren's syndrome, a condition that effects saliva production in the mouth, causes Exfoliative Chelitis.
We know for sure, because it is verified in independent research, that AIDS patients suffer from Exfoliative Chelitis. We know for sure, because it is verified in independent research that those people who have Exfoliative Chelitis of unknown origin, have a much higher likelihood of Anxiety Disorder and Hypothyrodisim. And we know for sure, because it is reported in academic literature, that lip filler patients report they experience desqueamation (exfoliation of lip skin).
So to to figure out what is the root cause of Exfoliative Chelitis we need to ask what do these various , extremely diverse , patient groups have in common. What is the common factor?
The answer is xerostomia (or dry mouth).
Research concluded that Oral Candida infection resulted in Exfoliative Chelitis in AIDS patients. . Well, it may well be true that candida contibutes to EC in aids patients. However, oral candida infection or thrush on average does not produce the symptoms of Exfoliative Chelitis.
So there has to be another factor. Why does candida attack the lip skin specifically in HIV patients. since a) HIV reduces salivary excretions and b) antiretroviral therapy results in dry mouth, it could be argued that a dry mouth causes Chelitis (the damaged and vulnerable lip skin is then a good medium for the candida to proliferate in immunocompromised patients).
Similarly, Sjoren's syndrome patients also get Exfoliative Chelitis. It is a very different condition from AIDS. The condition effects saliva exertions in the mouth. However, Sjoren's syndrome patients with EC also demonstrate candida infection. Why? Because the dry mouth, without proper antimicrobial properties, is vulnerable to secondary infection by candida.
So my conclusion is that candida infection observed in both Sjoren's patients and AIDS patients who have Exfoliative Chelitis is secondary to primary cause which is xerostomia.
Similarly , Exfoliative Chelitis patients with idiopathic (unknown cause) , according to literature , have a much higher likelihood of having an anxiety disorder.
Well, we know, because it is verified in independent research, that anxiety disorder results in a ) mouthbreathing and b)generalised dry mouth. What is more, a lot of anxiety disorder patients are on medication which increase the chances of having a dry mouth.
Not everyone who has xerostomia has EC but pretty much every population of patients who have EC have a high likelihood of having xerostomia.
So how come EC occurs in some people and not others with Sjoren's syndrome?
I can't say definitlevely. Maybe it has to do with severity of the xerostomia and other unknown factors (immune system, other lifestyle factors, anatomical structure of mouth ect). I just can't say. I would need to do independent research to establish this.
What I think I can conclude, with some, confidence, is that there is a high correlation between Exfoliative Chelitis and Xerostomia.