Study carried out among children of around 12 year age group in an orphan house with less carbohydrate diet is:

The observational studies like Hopewood House study have played a crucial role in determining the role of dietary sugars in dental caries etiology.  The study were done on orphan children. In these observational studies, the relationship between the disease (dental caries) and possible causative and confounding factors (sugar consumption, frequency of consumption) were observed. In interventional studies like Vipeholm studies and Turku sugar studies, diets of groups of people were purposefully altered and the effect of this intervention observed.  There is vast amount of data on the role of sugar consumption in diet and the frequency of its consumption on dental caries. Pediatric dentistry principles and practice. MS Muthu and Sivakumar  chapter 19