The walls of Dr Walter Keller’s dental surgery in Munich, Germany, are full of photos of Khmer temples such as Angkor Wat, Bayon and Ta Prohm.

His patients learn about the Kingdom of Wonder while they have their teeth drilled and gums treated.

The 53-year-old dentist is a great admirer of Cambodia and wants to help the children in particular.

He has just wrapped up his fourth volunteer stint at Angkor Hospital for Children since 2009, and also combined the stay with his photo exhibition at FCC Phnom Penh that finishes on Sunday.

When Dr Keller was a boy, he had bad teeth, but a clear goal –he wanted to become a dentist because in those days a dentist’s job was one of the best paid professions in Germany.

His plan was to study, to work for 15 years, become rich and spend the rest of his life on traveling the world and helping poor people.

“Well, I never became rich,” he said. “Therefore I must go on working until retirement, but I became a traveler anyway.”

He started donating money for a school project in Cambodia. His lawyer, Dr Siegfried Zinckiest from Munich, had founded a Junior High School in Peak Snag near Siem Reap and invited Keller to the opening ceremony in February 2008.

Dr Keller returned to Cambodia in 2009, wanting to volunteer as a dentist.

He was advised to volunteer at Angkor Hospital for Children instead, and since then has returned several times.

“The dental clinic at this hospital is the main reason why I return to Cambodia every year”, Dr Keller said. “The equipment fulfills western requirements, and the children seem to be braver and more capable of suffering than most children in Germany.”

In particular he likes the outreach programs, when he and his local colleagues visit schools outside Siem Reap and treat hundreds of children.

Dr  Keller is also a member of the board of directors of Hilfe für Kinder in Kambodscha (Help for Children in Cambodia), which runs a boarding school in Siem Reap province in cooperation with local Life & Hope Association.

But the doctor is not only skilled with his drill – he’s also a dab hand with the camera and his work is on display at FCC Phnom Penh, in an exhibition titled, Light and Shadow.

Photos include black and white images of monks at Phnom Kulen, rays of sunlight in a gangway of Angkor Wat, and an illuminated Bayon temple during an open air concert by singer Bospha Phan.

Dr Keller said, “I play with the presence and absence of light, and I Iike black and white photos, giving them a more journalistic and documentary look, similar to the works of my idol John McDermott.”

Dr Keller returned to Germany this week after finishing his stint at Angkor Hospital for Children last weekend. He will return in the second half of 2013.