While some dogs seem gifted with healthy chompers, there are some breeds that have more than their fair share of dental issues. Genetics plays a huge role in how a dog's mouth is formed, and can mean the difference between a regular plaque buildup to severe tooth and gum problems. For example, the pawdorable brachycephalic faces of Boxers and Boston Terriers form a wider mouth that makes them more prone to tooth misalignment, plaque buildup and periodontal disease. Small and toy breeds have a bigger problem as all 42 teeth struggle to fit into their tiny mouths. Sometimes, baby teeth don't come in until a dog is past puppyhood, or don't reabsorb when the adult teeth grow in, and fight for space in a mouth already full. Narrow muzzled dogs like Shelties can be prone to infections in gum pockets, or overbites. A thickening of the gums, or gingival hyperplasia, can occur in breeds like Boxers and Mastiffs. All these conditions can lead to plaque buildup, tissue and tooth loss, periodontal disease, and most importantly, pain for your furry buddy. Check out our list of the top 10 dogs with the worst teeth to help you decide if these breeds are for you.