ABSTRACT
The aim of this study was to determine the proximity of the nasopalatine canal (NPC) to the maxillary central incisor root (MCIR). The study included 120 cone beam computed tomography scans obtained from the Center for Implant Dentistry, Loma Linda University, between June 2006 and September 2009. They were equally distributed into six groups: (1) 21- to 40-year-old men, (2) 21- to 40-year-old women, (3) 41- to 60-year-old men, (4) 41- to 60-year-old women, (5) 61- to 80-year-old men, and (6) 61- to 80-year-old women. The closest distances between the NPC and the MCIR (NPC-to-MCIR) were measured at the midroot (bisecting palatal cementoenamel junction to root apex) and the apex levels. Differences between the groups were analyzed using a t test and 1-way analysis of variance at a significance level of α = .05. The overall mean NPC-to-MCIR distances at the midroot and apex levels were 3.05 ± 1.64 and 5.22 ± 1.56 mm, respectively. The modes of the NPC-to-MCIR distances at the midroot and apex levels were in the range of 1.01-2.00 mm and 4.01-5.00 mm, respectively. The mean NPC-to-MCIR distance was significantly greater in men than in women at the midroot level (P < .05) but not at the apex level (P > .05). The mean NPC-to-MCIR distance was significantly shorter for the youngest age group than the other two age groups at the midroot level (P < .05). However, at the apex level, the youngest age group had a significantly shorter distance compared with the oldest age group (P < .05) but not the middle age group (P > .05). The results of this study suggest that, to avoid NPC penetration, more care must be exercised during immediate implant placement at the midroot level of a maxillary central incisor in women and younger patients because of the root proximity to the NPC. Tapered implants may also be beneficial in such situations.