The suit, against manufacturer and distributor of oral products Ranir, is being filed through P&G's wholly owned subsidiary, The Gillette Company.
The company claims that Ranir sells replacement toothbrush heads "specifically designed to fit" Oral-B power toothbrushes that are manufactured by Braun and sold by Gillette in the United States.
P&G said that Ranir, which sells its product under various retail store brand names, is violating Braun's patents relating to the connection between the brushhead and the handles of the Oral-B toothbrushes.
"We cannot allow other companies to copy our products and infringe our patents," said Gary Cohen, vice president of Oral-B business management in a statement on Monday.
"Oral-B's brushhead designs are a competitive advantage. We intend to protect the investment we have made into the research, development and intellectual property of our products," he added.
The company said its lawsuit seeks to stop Ranir from selling the products and to recover damages for violations of P&G's intellectual property rights.
In January, P&G reported strong first full quarter financial results following its merger with Gillette. Results were well ahead of expectations after the world's largest consumer goods company more than tripled revenue growth, the fastest rate in more than ten years.
P&G finalised the $57 billion to merge with Gillette in the fall of last year and has not looked back. The company said that its unit volume grew 27 per cent, while net sales also grew by 27 per cent to reach $18.34 billion, supported by strong increases in the figures for both the Gillette and P&G divisions.