Can wearing metal dental braces over a period of time cause intestinal infection ? leading to stomach pains, vomit and high white blood counts in cbc

No: Metal braces are unlikely to cause the symptoms you described. Have a healthy diet, exercise 30 minutes/day, drink plenty of water, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Get HPV vaccine

No: Braces do not cause infections. Bacteria cause infections. You need to see a Gastroenterologist to evaluate/treat GI infection and an Orthodontist to evaluate your oral health. You may also need to be evaluated for nickel allergy.