Periodontal disease is one of the most common conditions affecting dogs worldwide and is reported to be particularly prevalent in racing greyhounds. A range of potential risk factors have been hypothesised. Previous research has suggested, regular tooth brushing can reduce both calculus and gingivitis, but the frequency required is unclear. Here, we report a controlled blinded in-situ in which kennel staff brushed 160 racing greyhounds’ teeth (living at six kennel establishments), either weekly, daily or never over two-month period. All visible teeth were scored for calculus and gingivitis, using previously validated scales. We calculated average scores for each of three teeth groups and overall averaging the teeth groups. Changes were compared to baseline. After two months, the total calculus scores (controlling for baseline) were significantly different in the three treatemnet groups, (F(2,129) = 10.76, p<0.001) with both weekly and daily brushing resulting in significant reductions. Gingivitis was also significantly different (F(2,128) = 4.57, p=0.012), but in this case, only daily brushing resulted in a significant reduction. Although dogs in different kennels varied significantly in their levels of both calculus (F(5,129) =8.64, p<0.001), and gingivitis (F(5,128)=3.51 p=0.005), the intervention was generally similarly effective in all establishments. Teeth groups varied and incisors were not significantly affected by treatment. Since trainers implementing the routine, reported minimal time commitment and positive experiences, we suggest that daily brushing is recommended for racing greyhounds, and that demonstrations should include attention to all teeth groups including incisors. Similar trials need to be conducted with retired greyhounds since these have been shown to present particularly high levels of periodontal disease.