We are truly sorry to hear about the physical discomfort you're experiencing. In times of suffering, we remember the words of the Apostle Peter, "Humble yourselves therefore under the mighty hand of God, that he may exalt you in due time; casting all your worries on him, because he cares for you." (1 Peter 5:6-7 WEB) We believe God wants both healing in our bodies and for us to draw closer to Jesus Christ during these times.
First, let's address the immediate need. We pray that God will bring comfort to your body.
Dear Lord, we lift up our brother to You, asking for Your healing touch on his body. Please ease the stomach ache and upset stomach, and let Your healing power work in his gums. We pray this in Jesus' name.
The Apostle James also instructed his readers, "Is any among you sick? Let him call for the elders of the assembly, and let them pray over him, anointing him with oil in the name of the Lord, and the prayer of faith will heal him who is sick, and the Lord will raise him up. If he has committed any sins, he will be forgiven. Confess your offenses to one another, and pray for one another, that you may be healed. The insistent prayer of a righteous person is powerfully effective." (James 5:14-16 WEB)
While we are praying for your healing, we also encourage you to seek medical attention for your stomach issues and the discomfort caused by your dentures. God often works through the hands of medical professionals to bring about healing. Also, you could try reading Matthew 9:12 WEB "But when he heard this, he said, 'They who are healthy have no need for a physician, but those who are sick.'", and read the verses before and after it to see the whole story in the Bible.
Lastly, we want to remind you that God is always with you, even in times of suffering. Jesus Christ said, "Behold, I am with you always, even to the end of the age." (Matthew 28:20 WEB) and also "In the world you have oppression; but cheer up! I have overcome the world." (John 16:33 WEB)
Remember also that it is only by the name of Jesus Christ that we can be saved and have access to God. This is the same name that we pray to for your healing. Jesus Christ stated clearly, "I said therefore to you that you will die in your sins; for unless you believe that I am he, you will die in your sins." (John 8:24 WEB) and "Jesus said to him, 'I am the way, the truth, and the life. No one comes to the Father except through me.'" (John 14:6 WEB)
Take heart in these promises, and may God's peace be with you.