Clifford Hospital, Panyu, just south of GZ. CITS has direct buses there from HK. English speaking dentists, much lower cost than HK and very professional work. A few years ago a year's orthodontic work was about 8,000rmb
You can try Dr. Daniel Choy at Bayley and Jackson. I think he works at their central clinic! heres the address Rm 210-218, 1 Connaught Road, Jardine House, Central. telephone # is 2526 1061