3D stereophotogrammetry in children and adolescents with Scleroderma En Coup De Sabre/Parry-Romberg Syndrome: Description of a novel method for monitoring disease progression.

Background: The diagnosis of Scleroderma En Coup de Sabre (ECDS)/Parry Romberg Syndrome (PRS) is mainly based on characteristic clinical findings. Methods to objectively monitor the course of the disease in a standardized way are lacking. Objectives: This descriptive, retrospective, single centre cohort study aims to describe the contribution of 3D photographs in the assessment of the degree of facial asymmetry changes over time in growing children and adolescents with ECDS and PRS. Methods: Six patients diagnosed with ECDS/PRS, with a follow-up period of at least 24 months and at least three 3D photographs were included. Mirroring these 3D photographs was automatically performed using surface-based matching to generate a colour-coded distance map, illustrating the inter-surface distance and thereby asymmetry between the original and mirrored 3D photographs. The percentage of absolute distances between the original and mirrored 3D photograph were calculated. Results: In two patients, impressive decreases in the percentages of absolute distance levels over time were found, whereas the other patients did not show progression of asymmetry over time. Conclusion: This study shows the potential of 3D stereophotogrammetry as an objective tool to measure disease activity over time in patients with ECDS/PRS.

Integration of digital dental casts in cone beam computed tomography scans-a clinical validation study.

OBJECTIVES: Images derived from cone beam computed tomography (CBCT) scans lack detailed information on the dentition and interocclusal relationships needed for proper surgical planning and production of surgical splints. To get a proper representation of the dentition, integration of a digital dental model into the CBCT scan is necessary. The aim of this study was to validate a simplified protocol to integrate digital dental models into CBCT scans using only one scan. MATERIALS AND METHODS: Conventional protocol A used one combined upper and lower impression and two CBCT scans. The new protocol B included placement of ten markers on the gingiva, one CBCT scan, and two separate impressions of the upper and lower dentition. Twenty consecutive patients, scheduled for mandibular advancement surgery, were included. To validate protocol B, 3-dimensional reconstructions were made, which were compared by calculating the mean intersurface distances obtained with both protocols. RESULTS: The mean distance for all patients for the upper jaw is 0.39 mm and for the lower jaw is 0.30 mm. For ten out of 20 patients, all distances were less than 1 mm. For the other ten patients, all distances were less than 2 mm. CONCLUSIONS: Mean distances of 0.39 and 0.30 mm are clinically acceptable and comparable to other studies; therefore, this new protocol is clinically accurate. CLINICAL RELEVANCE: This new protocol seems to be clinically accurate. It is less time consuming, gives less radiation exposure for the patient, and has a lower risk for positional errors of the impressions compared to other integration protocols.

Three-dimensional facial simulation in bilateral sagittal split osteotomy: a validation study of 100 patients.

PURPOSE: Three-dimensional (3D) virtual planning of orthognathic surgery in combination with 3D soft tissue simulation allows the surgeon and the patient to assess the 3D soft tissue simulation. This study was conducted to validate the predictability of the mass tensor model soft tissue simulation algorithm combined with cone-beam computed tomographic (CBCT) imaging for patients who underwent mandibular advancement using a bilateral sagittal split osteotomy (BSSO). MATERIALS AND METHODS: One hundred patients were treated with a BSSO according to the Hunsuck modification. The pre- and postoperative CBCT scans were matched and the mandible was segmented and aligned. The 3D distance maps and 3D cephalometric analyses were used to calculate the differences between the soft tissue simulation and the actual postoperative results. Other study variables were age, gender, and amount of mandibular advancement or rotation. RESULTS: For the entire face, the mean absolute error was 0.9 ± 0.3 mm, the mean absolute 90th percentile was 1.9 mm, and for all 100 patients the absolute mean error was less than or equal to 2 mm. The subarea with the least accuracy was the lower lip area, with a mean absolute error of 1.2 ± 0.5 mm. No correlation could be found between the error of prediction and the amount of advancement or rotation of the mandible or age or gender of the patient. CONCLUSION: Overall, the soft tissue prediction algorithm combined with CBCT imaging is an accurate model for predicting soft tissue changes after mandibular advancement. Future studies will focus on validating the mass tensor model soft tissue algorithm for bimaxillary surgery.