When Charlie Roberts makes house calls, he goes all the way.
Sunlight slips through the bamboo wall and lies like a row of spindly sticks on the dirt floor.
Outside, a gas generator chugs along, the light bulb flickers. Dentist Charlie Roberts, a shiny instrument in his hand, shoos away another fly and bends over his patient. The little boy, a refugee in this Cambodian camp, tries to be brave. Teams also normally include ophthalmologists, optometrists and supporting staff. Everyone is a volunteer and volunteers pay their own expenses.