After his study at Utrecht University Berry opened his private clinic in Huizen (The Netherlands) in 1979. Postgraduate courses in the field of myofunctional therapy, reconstructive dentistry, periodontology and implantology had been attended in both the Netherlands as well as abroad.

From 1979 up to 2008 his practice was limited to prosthodontics, extensive reconstructive dentistry, periodontology and gnathology (whether it would be functional or skeletal of origin) and treating functional disturbances due to oro myofunctional problems.

Since 1986 he is giving lectures and courses on myofunctional therapy and implantology in the Netherlands, Belgium and Latvia. He was secretary of the Dutch Society for post graduate courses during 5 years. As of 2003 his practice was limited to surgery and implantology. As of 2007 he is Fellow of the international College of Dentists. In 2011 he stopped working in his private dental clinic and is just lecturing Myofunctional science and giving clinical courses on myofunctional therapy.