Guidelines for Maxillary Incisal Edge Position—A Pilot Study: The Key Is the Canine

PURPOSE: The purpose of this pilot study was to evaluate the relationship between the vertical position of the maxillary central incisal edge and the maxillary canine relative to the maxillary lip line in repose of dentate patients. This may be beneficial for clinicians in establishing guidelines for the rehabilitation of edentulous patients. MATERIALS AND METHODS: One hundred and four Caucasian dentate patients (59 men and 45 women) between the ages of 30 and 59 years were evaluated. A millimeter ruler was used to measure the maxillary right central incisor edge and the maxillary right canine tip to the maxillary lip in repose. Data were collected in reference to sex and age. RESULTS: For the female group, average central incisor exposure in relation to the relaxed maxillary lip line was 3.8 mm, and the range of exposure was -1 to +8 mm. In the 30- to 39-year olds (17 patients), the average was 4.1 mm with a range of 0 to 8 mm. The average in the 40- to 49-year-old group (16 patients) was 2.8 mm with a range of -1 to +6 mm. In 50- to 59-year olds (12 patients), the average was 1.8 mm with a range of -1 to +5 mm. In the male group, the average central incisor exposure was 2.5 mm, and the range was -3 to +7 mm. The average for the 30- to 39-year-old group (20 patients) was 3.2 mm with a range of 0 to 7 mm. For the 40- to 49-year group (18 patients), the average was 2.4 mm and for 50 to 61 years (21 patients), it was 1.4 mm with a range of -3 to +5 mm in both latter age groups. The canine position for the female group average exposure was 0 mm, with a range of -2 to +2 mm. For the 30- to 39-year old group, average exposure was 1 mm with a range of -1 to +2 mm. The 40- to 49-year-old group exposed an average of 0.4 mm with a range of -1 to +2 mm. For the 50- to 59-year old group, canine exposure was -0.5 mm with a range of -2 to +1 mm. The male average canine exposure was -0.5 mm, and the range was -3 to +2 mm. For the 30- to 39-year old group, the average was 0.9 mm with a range of -1 to +2 mm. The 40- to 49-year-old group exposed an average of 0.2 mm, with a range of -1 to +2 mm. For the 50- to 59-year old group, average was -0.9 mm with a range of -2 to +1 mm. CONCLUSIONS: There was a large range of maxillary central incisal exposure in relation to the maxillary lip line. The average dimension of central incisor exposure represented less than 30% of the subjects in the study and could not be used predictably to assess incisal edge position. The range of canine exposure was narrower. The average dimensions of canine exposure to the lip were within 1 mm for both men and women in all age groups. Further studies are needed to confirm these preliminary results. The average dimensions for the different sex and age groups related to canine exposure represented a greater proportion of the subjects. Therefore, it is suggested that the average canine exposure dimension can be used clinically to assess anterior incisor edge position when restoring edentulous patients.