Inner Canthal Distance, Inter Pupillary Width, and Golden Proportion, as Predictors of Width of the Maxillary Central Incisors - An In Vivo Study

Abstract

BACKGROUND The mesio-distal width of anterior teeth can be determined by certain anthropometric measurements of face. The inter pupillary width is a facial landmark that is stable and does not modify after the age of 14 years. This study intended to determine if any relationship exists between inner canthal distances (ICD), inter-pupillary width (IPW), and golden proportion in determining the association between them and the maxillary central incisor width (CIW). METHODS 252 adult dentate subjects of age group 18 - 26 years who were free from dentofacial deformities were evaluated in the present in vivo study. The mesiodistal measurement of each maxillary central incisor, inner canthal distance (ICD), interpupillary width (IPW) was measured. The inner canthal distance of each subject was multiplied by a decreasing function of the geometric progression value (0.618) to provide the total width of two central incisors. The product was divided by 2 to get the width of a maxillary central incisor. A 't' test was used to establish significant differences if any in the mesiodistal width of the maxillary central incisors (CIW), inner canthal distance (ICD), and inter-pupillary width (IPW). Concurrence between the measured and calculated central incisor widths was evaluated using Pearson's correlation coefficients. RESULTS The mean ICD of male and female subjects was 33.03 ± 3.037 mm and 30.75 ± 2.89 mm, respectively. The mean IPW of male and female subjects was 62.26 ± 2.99 mm and 58.46 ± 2.73 mm, respectively. The mean CIW of male and female subjects was 19.98 ± 1.96 mm and 18.54 ± 1.87 mm, respectively. A high correlation was found between the measured and calculated width of central incisors (r=0.954 and r=0.974 in males and females). CONCLUSIONS There is a high positive correlation between ICD and CIW and it exists in the golden proportion. On the other hand, it was seen that the IPW and CIW were not in golden proportion. The mean of calculated CIW was significantly higher compared to the measured CIW in both males and females. ICD was seen as a significant factor in determining the CIW in males and females. All the facial and dental measurements were greater for men than for women; however, no significant differences were found between sexes with respect to ICD. KEY WORDS Inner Canthal Distance (ICD), Inter Pupillary Width (IPW), Central Incisor Width (CIW), Golden Proportion