The Japan Dental Federation's political donation scandal is a clear reminder, observers say, of lobbying by a group known for its persistent efforts to push up the prices of medical services.

Tokyo prosecutors on Wednesday arrested Mikimasa Takagi, a former JDF chairman, and two former JDF executives in connection with allegations that JDF donated ¥100 million and ¥95 million respectively to Liberal Democratic Party and Democratic Party of Japan members of the Upper House, in excess of the annual legal limit of ¥50 million. They are alleged to have made the payments through complex channels to obfuscate their origins.

The allegations recall a scandal in 2004 in which JDF donated ¥100 million to the political faction of the late Ryutaro Hashimoto, a Liberal Democratic Party heavyweight and a former prime minister, and disguised it.