Background: There is a clear debate about the role of bad oral habits (thumb-sucking and biting nails) and on oral health and the state of the dental caries, but there is no doubt that continuing these bad habits until advanced ages will lead to deep and difficult problems to solve. Objective: The purpose of study was to evaluate the effect of bad habits, include finger sucking and nail biting on dental caries among children aged from 6 to 10 years old. Subjects and methods: In Al-Hilla city, Iraq, a comparative study was conducted in which (200) primary school students aged between 6 to10 years old were involved. A questionnaire filled out by their parents was used to gather information related to the bad oral habit, and then all the students were examined clinically for caries experience. Data was statically analyzed utilizing (SPSS version 21, Chicago In Press, IL, USA). Results: The statistical analysis showed a highly significant difference (p>0.01) in the occurrence of dental caries between children with bad oral habits than children without bad habits. The mean of DMFS score of case was 3.480 ± (0.272) and mean of dmfs score of case was 8.380 ± (0.431). Conclusion: Bad oral habits found to be a risk factor for the development dental caries. Key words: Bad habits, Children, Nail biting, Thumb sucking.
In order to serve the field of knowledge in the field of design and analysis of experiments by adopting formulas and methods that are easy and simple in arithmetic work, especially in experiments that require many calculations for squares, including tests of type
