Digital surface photogrammetry for anthropometric analysis of the cleft infant face

Completing the 3-dimensional picture

Orthodontics has a commitment to precision and accuracy similar in concept to physical engineering. Both work in a 3-dimensional (3D) world--the engineer designing and modeling physical products, and the orthodontist diagnosing and treating patients. To achieve the best possible results, both fields have readily adopted and successfully implemented highly advanced mathematical techniques and sophisticated protocols. Today, a notable difference between the 2 fields relates to the data input and analysis/modeling tools that are now available. Technology advances in the past 5 years have started to erode these barriers to safely make human 3D data input as precise and easy to obtain as physical 3D object input. Many are familiar with the advances in 3D computed tomography, specifically cone-beam technology; this article focuses on a sister imaging technology called 3D surface imaging. These 3D systems enable extraoral imaging protocols to be equally precise in providing highly accurate 3D facial surface images for diagnosis, analysis, treatment monitoring, simulation, and outcome evaluation.

A new method to quantify subtle morphological deformities in nasal profile curvatures and its application for analysis of unilateral cleft lip noses

OBJECTIVE

The authors conducted the present study to elucidate what elements characterize the nasal profiles of patients with unilateral cleft lips (CLs).

MATERIALS AND METHODS

A total of 40 Japanese unilateral CL patients were studied. For each patient, the nasal profile curve was traced on three-dimensional computer tomography image. Then four points were marked on the contour. The points were NAS (Nasion), MAP (the Most Anterior Point on the nasal profile curve), GPRN (the Genuine Pronasale: the point on the nasal curve at which the curve protrudes most), and SBN (Subnasale: the point at the columellar base). Using specially designed software, the distances between these marking points were measured along the nasal profile curve.

RESULTS

In CL patients, the distance between the MAP and GPRN is longer, and the GPRN is located more inferiorly than in non-cleft persons.

CONCLUSION

The nasal tip tends to become round and to droop in unilateral CL patients. In order to avoid this deformity pattern, the nasal tip should be reshaped to present a sharper curvature and corrected superiorly.

Systematic contact-free 3D topometry of the soft tissue profile in cleft lips

OBJECTIVE

To evaluate the clinical application of three-dimensional (3D) imaging for the analysis of a broad variety of cleft lips and to conduct a systematic analysis.

DESIGN

This was a prospective study using a noncontact 3D laser scanner to acquire the preoperative 3D facial profiles. The data sets were analyzed qualitatively and quantitatively. The data were expressed by ratios and scores.

PATIENTS

Forty nonsedated patients (1 to 39 years, average age 2.7 years) with unilateral cleft lip, cleft lip and alveolus, or complete unilateral cleft in Cambodia.

RESULTS

The acquired 3D data sets (mean acquisition time: 2.5 seconds) from facial surfaces were of diagnostic quality in 27 of 40 patients (average age, 14.2 years). In these cases all anatomical structures could be mapped precisely by means of landmark positioning in the range of millimeters. A new method of systematic analysis could be elaborated, allowing for data set expression independent of size and growth factors. In children under age 3, the measuring procedure was of limited value because of motion artifacts and was successful in only 6% (1 of 15) of these patients.

CONCLUSION

The system offers a solid and precise tool for 3D imaging of the complex cleft lip anatomy in compliant patients and is useful for preoperative cleft assessment and follow-up. However, the application is limited in moving infants or uncooperative adults because of scanning time and acquisition method. The development of motion tracking and faster devices could eliminate motion artifacts.