dense / dents are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
dense: (adjective) permitting little if any light to pass through because of denseness of matter. (adjective) hard to pass through because of dense growth. (adjective) having high relative density or specific gravity. (adjective) slow to learn or understand; lacking intellectual acuity; ; ; - Thackeray.
dents: (noun) an appreciable consequence (especially a lessening). (noun) an impression in a surface (as made by a blow).
dense: d·EH·n·s
dents: d·EH·n·t·s
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)