Acknowledgements
Nourhan
We would like to express our gratitude to Dr. Nourhan M. Aly, Pediatric Dentistry and Dental Public Health Department, Faculty of Dentistry, Alexandria University, for carrying out the statistical analysis of this study. We would also like to thank Dr. Karim Khalifa and Dr. Abdel-Aziz Eltaweel, intern students at Faculty of Dentistry, Alexandria University, for their help in photography through the study.