Dentistry has a long history dating back 7,000 years when the first evidence of dental practices were seen. Throughout ancient times and the middle ages, dental treatments were rudimentary with "tooth worms" believed to cause decay and extractions the main procedure performed. The 1700s saw important developments like the first dental forceps and the recognition of dentistry as a distinct medical profession. The 19th century brought advances in anesthesia using nitrous oxide and ether as well as the commercial production of porcelain teeth. The modern era of dentistry began in the late 19th/early 20th century with the discovery of x-rays, innovations in dental materials like amalgam and the founding of major dental organizations worldwide.