Overhanging tooth restorations are defined as an extension of amalgam restorative material beyond or after the cavity preparation lines, lead to environmental change of the balance between beneficial bacteria and periodontopathogens, lead to periodontal breakdown. This study aim was to obtain the prevalence of tooth amalgam overhang in Erbil city population. Amalgam overhang restoration prevalence study about 1200 patients examined in College of Dentistry, Hawler Medical University, and (Khanzad) Specialized Center for Dentistry for the presence of proximal amalgam restoration. The patients also have who proximal restorations were examined clinically using dental mirror and explorer and then radiographically by taking bitewing radiograph. The results showed statistical analysis for the prevalence of amalgam overhang among patients attitude in the study (25.4%). The distribution of amalgam overhang was 59.4% for upper teeth and 40.6% for lower teeth and 64.6% for distal surface, 36.4% for the mesial surface. In conclusion, there is a high percentage of amalgam overhang among population that need treatment to prevent subsequent periodontal diseases.

Aims of this study were to determine both the Bolton anterior and overall ratios in a representative sample of Erbil schoolchildren of Normal occlusion and Cl I, Cl II div I, div II, and Cl III malocclusion, also to find if there are any gender differences. Numerical data were obtained, comprised of 320 samples study casts of students with a mean age of 13–15 years selected from different schools in Erbil City. The casts were divided into 5 groups according to the type of malocclusion: Normal (n = 64), Cl I (n = 64), Class II div I (n = 64), Class II div II (n = 64), and Class III subjects (n = 64). The measurement of the greatest mesiodistal width of the teeth was performed using digital Vernier directly on the study casts, from the distal surface of the left first molar to the distal surface of the right first molar. The overall and anterior ratios between the maxillary and mandibular teeth were computed and evaluated using Bolton’s method. The results revealed that the mean anterior ratio (78.863) was higher and statistically signifi cantly different from anterior Bolton’s (77.2) and also the mean overall ratio was not statistically signifi cant different from Bolton’s ratio (91.3) (P = 0.239), with respect to the overall and anterior ratios among all the groups, statistically significant differences were found. Differences between genders were analyzed using a t-test. The results showed that there were no signifi cant differences between males and females. There were non-significant differences between the findings of the present study and those of Bolton’s study for overall ratio and anterior ratio, but among all five classifications, there was a significant difference of Erbil population not similar to Bolton ratio and there was no significant difference between males and females.