Mouth dryness

• Use a fluoride toothpaste and/or use a fluoride rinse.
• Use a moisturizing dry mouth mouthwash and avoid those with alcohol. 
• Avoid spicy, acidic, and sugary foods before bed. 
• Limit or eliminate alcohol and caffeine, as well as tobacco and drug use.

You may be able to treat your dry mouth in the morning. However, it is also important to know if there’s an explanation why you have it, especially if it's chronic. Healthline listed possible causes like Mouth Breathing, Medications, Aging, Diabetes, Alzheimer’s disease, Sjogren’s disease, Cancer therapy, Tobacco and alcohol or Recreational drug use. 

If you think there’s nothing more to it, then you can try these home remedies:

• Chewing suger-free gum or sucking on sugar-free candies
• Staying hydrated
• Using a cold air humidifier in your bedroom
• Avoiding caffeine or alcohol
• Chewing thoroughly before swallowing
• Avoiding dry, spicy or salty foods

I hope it helps.

A dry mouth, or xerostomia, is the sticky sensation you may feel when you don’t have enough saliva or spit in your mouth. Waking up with a dry mouth can be uncomfortable and may make it hard to swallow. When there’s not enough saliva in your mouth, it can lead to a dry mouth. 

Dry mouth is common. It affects nearly 22% of the world’s population. Older adults tend to deal with it more often. But several things can cause you to wake up with it. A dry mouth can be a signal of a health problem or a side effect of certain medications.

Try to avoid:

• Acidic, spicy, salty, dry, and sugary foods and beverages.
• Alcohol, caffeine, and carbonated drinks.
• Mouthwashes with alcohol or peroxide may dry your mouth even more.
• Smoking.

How can I prevent dry mouth?

You may not be able to prevent all causes of dry mouth. But you can prevent some. Try to:

• Drink plenty of water. Aim for about eight glasses of water a day, sipping frequently.
• Use a humidifier, especially in your bedroom, to prevent dry mouth at night.
• Breathe through your nose, not your mouth.

Avoid:

• Over-the-counter medications that can cause dry mouths, such as antihistamines and decongestants. Ask your healthcare provider about a different treatment or medication.

I hope the above help!