Amoxicillin just isn't strong enough to fully deal with tooth abscess at such low doses, even though dentists prescribe the standard 500mg/8 hours. To clear the infection up asap the dosage is 3 grams amoxicillin at once, followed by another 3 grams 8 hours later. This will mean swallowing a total of 12 500mg pills. This is exactly what I've. Strong antibiotics such as amoxicillin can disturb the balance of these yeast cells in the mouth. The result is an overgrowth of the yeast cells, causing white spots in the mouth. Without a remedy, the spots can grow and spread into large white mouth patches. Other medications that can also lead to white patches include.