A tooth abscess differs from a gum abscess by the source of the original infection. The tooth abscess (or periapical abscess) originates from the pulp of the tooth and exits out the tooth's apex at the bottom of the root. A gum abscess (or periodontal abscess) starts in a gum pocket outside of the tooth next to the root.
Click here to see a 239-word sentence that is a perfectly fine sentence (structurally). When two independent clauses are connected by only a comma, they constitute a run-on sentence that is called a comma-splice. The example just above (about the sunscreen) is a comma-splice.
1 Ways of Correcting Comma Splices.  2 Here are some comma splice errors: Wrong: We hiked for three days, we were very tired.Wrong: The television is too loud, the picture is fuzzy. 3  There are five ways to correct a comma splice. 4  1. Change the comma to a period and capitalize the next word.Correct: We hiked for three days.