The three-dimensional relationship on a virtual model between the maxillary anterior teeth and incisive papilla

Statement of problem. The incisive papilla as an anatomical landmark has historically been used to determine anterior incisal tooth position for complete denture prostheses. There are numerous data regarding its position, but 3-dimensional orthographic measurements are scarce. Purpose. The purpose of this study was to evaluate the orthographic anteroposterior distance between the posterior border of the incisive papilla and a reference point or vector. Material and methods. Using a 3-dimensional laser scanner and reconstruction computer software, 9 measurements were made orthographically on an individually established reference plane. The following 3 measurements were made to determine the spatial relationship between the anterior tooth and the incisive papilla: IP, incisor to papilla, IIC, incisor to intercanine line, and ICP, intercanine line to papilla. In addition, the following 6 measurements were made to evaluate the correlation of the factors determining arch shape with the previously described 3 measurements: ICW, intercanine width, AL, arch length, AW, arch width, ICR, incisor to canine radius, ICA, incisor to canine angle, and IMA, incisor to molar angle. The correlation among all values was investigated. Descriptive statistics and an independent sample t test between genders was performed (α=.05). Results. The average IP distance (SD) was 11.96 (1.37) mm with no significant gender difference (P=.052). There were gender differences in IIC (P=.001), AL (P=.017), and ICA (P=.013). ICA had the largest negative or positive correlation coefficients with parameters related to the incisive papilla such as IP, IIC, and ICP. Conclusions. The mean IP value obtained by 3-dimensional orthographic measurements was significantly larger than the classical data, however, it is impossible to make direct comparisons. The central incisor position of dentate subjects has a significant relationship with the ICA value which represents the premaxillary divergence. (J Prosthet Dent 2007;98:312-318)This study was supported by a grant of the Korea Health 21 Research and Development Project, Ministry of Health and Welfare, Republic of Korea (03-PJ1-PG1-CH09-0001).