Determination of Maxillary Incisal Edge Position using Canine Visibility as a Guide – An In vivo Study

Purpose: To evaluate the reliability of the visibility of the central incisor & the canine for the cervico incisal positioning of anterior maxillary teeth related to age & sex while the upper lip was in repose in dentate patients & the development of rehabilitation recommendations for edentulous individuals with regard to the location of the maxillary incisal edge

Methodology: 308 subjects [152 Males & 156 Females] belonging to the age of 30 to 59 years were selected using a simple stratified random technique. There were three age and sex groups: Group I was 30 to 39 years old, Group II was 40 to 49 years old, and Group III was 50 to 59 years old. The vertical distances (in mm) between the lower border of the upper lip and the right maxillary central incisal edge and canine tip were measured and recorded using adhesive tape marked with millimetres. A single examiner recorded all the measurements and the values were tabulated and subjected to statistical analysis.

Results: Men in Groups I and II had maxillary central incisor exposure ranging from +6 to -1mm, whereas males in Group III had exposure ranging from +5 to -2mm. There was an exposure range of +6 to -2 mm in females in Group I, +7 to -2 mm in Group II, and +5 to -2 mm in Group III for the central incisors. While the canine exposure in Group I and II and Group III ranged from +2 to -4mm in females, the exposure ranged from +3 to -3mm in men of all ages. In all groups, females had statistically significant (P0.05) more central incisor and canine exposure than men.

Conclusions: The canine visibility was less variable in all the age groups and in both males and females in comparison to the central incisor. When restoring edentulous individuals, the average canine exposure dimension can be employed for cervico-incisal location of the anterior maxillary teeth.