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.
Technically, a comma splice is a kind of run-on sentence, but they're harder to spot, so we're giving them their own section. A comma splice occurs any time a comma is inserted between two main clauses without a coordinating conjunction to connect them. Remember that a sentence fragment is just another term for 'incomplete sentence.'. 2  Sentence fragments usually lack either main verb or subject (or both). 3  If you're not sure if a sentence is a fragment, check that it has at least one main verb and subject.