Characteristics of the dogs and humans enrolled in this study.

F: female, SF: spayed female, M: male, CM: castrated male, Pom: Pomeranian, Dach: Dachshund, Mal: Maltese, Mix: Mixed breed a Control human who had not raised a dog within the past ten years b Number of times per week teeth were brushed c Closeness score between dog and owner: 0, no contact, 1, nearly no contact with dog kept outdoors, 2, nearly no contact with dog kept indoors, 3, frequent contact without oral contact, 4, frequent contact with oral contact Characteristics of the dogs and humans enrolled in this study.