Florian Peters

Is the Maxillary Sinus Really Suitable in Sex Determination? A Three-Dimensional Analysis of Maxillary Sinus Volume and Surface Depending on Sex and Dentition.

AbstractThe morphometric analysis of maxillary sinus was recently presented as a helpful instrument for sex determination. The aim of the present study was to examine the volume and surface of the fully dentate, partial, and complete edentulous maxillary sinus depending on the sex. Computed tomography data from 276 patients were imported in DICOM format via special virtual planning software, and surfaces (mm2) and volumes (mm3) of maxillary sinuses were measured. In sex-specific comparisons (women vs men), statistically significant differences for the mean maxillary sinus volume and surface were found between fully dentate (volume, 13,267.77 mm3 vs 16,623.17 mm3, P < 0.0001; surface, 3480.05 mm2 vs 4100.83 mm2, P < 0.0001) and partially edentulous (volume, 10,577.35 mm3 vs 14,608.10 mm3, P = 0.0002; surface, 2980.11 mm2 vs 3797.42 mm2, P < 0.0001) or complete edentulous sinuses (volume, 11,200.99 mm3 vs 15,382.29 mm3, P < 0.0001; surface, 3118.32 mm2 vs 3877.25 mm2, P < 0.0001). For males, the statistically different mean values were calculated between fully dentate and partially edentulous (volume, P = 0.0022; surface, P = 0.0048) maxillary sinuses. Between the sexes, no differences were only measured for female and male partially dentate fully edentulous sinuses (2 teeth missing) and between partially edentulous sinuses in women and men (1 teeth vs 2 teeth missing). With a corresponding software program, it is possible to analyze the maxillary sinus precisely. The dentition influences the volume and surface of the pneumatic maxillary sinus. Therefore, sex determination is possible by analysis of the maxillary sinus event through the increase in pneumatization.

Simulation of three surgical techniques combined with two different bone-borne forces for surgically assisted rapid palatal expansion of the maxillofacial complex: a finite element analysis

Surgically assisted rapid palatal expansion (SARPE) is a common treatment to correct transverse maxillary deficiencies. Finite element analysis was simulated for six designs of SARPE based on a computed tomography scan of a human skull: median osteotomy with palatal (type A) or alveolar ridge (type B) bone-borne force, additional lateral osteotomy with palatal (type C) or alveolar ridge (type D) bone-borne force, and additional pterygomaxillary separation with palatal (type E) or alveolar ridge (type F) bone-borne force. The transverse expansion was about 1.0mm. The distribution of von Mises stress and the displacement were evaluated. The largest stress distribution was after types A and B, followed by types C and D, and finally types E and F. Displacement increased simultaneously. Palatal bone-borne forces (types A, C, and E) led to higher stress distributions in the midface and maxilla, but to a more parallel expansion compared with alveolar ridge-borne forces (types B, D, and F). The largest bony displacements at the midpalatal suture were anterior in all models. Increased weakening of the bony pillar of the facial skeleton and the use of palatal bone-borne forces leads to a decrease in stress distribution in the midface and to a more parallel transverse expansion of the maxilla.

Comparison of non-invasive radiographic measurements of soft tissue in the interdental space: a cadaver study

When we use implants the aesthetic appearance of the patient is dependent to a large extent on identification of factors that influence the presence of interdental papillae. The aim of this study was to compare the accuracy of different non-invasive measurements to indicate the top of the interdental papilla on dental radiographs. The sample comprised six fresh, partly edentulous cadavers. The distance from the level of the interproximal bone next to the tip of the papilla was measured (n=330) on standard radiographic images. Five different mixtures of radiopaque markers that had been used to highlight the top of the papilla in recently published studies were analysed. All measurements were compared with the bone probing length, which was evaluated clinically. The mixture of zinc oxide, eugenol cement, and tungsten powder (mean (SD) 0.14 (0.17)mm) deviated least from the control value. The deviation was significant (p<0.01) between the zinc oxide, eugenol cement, and tungsten powder mixture and each of the other individual combinations. The most accurate non-invasive radiographic method of measuring the interproximal length of the papilla relative to the alveolar bone crest was therefore the mixture of zinc oxide, eugenol cement, and tungsten powder.

Influence of Connecting Two Standalone Mobile Three-Dimensional Scanners on Accuracy Comparing with a Standard Device in Facial Scanning

ABSTRACT Objectives In this study is investigated if bundling of two scanners leads to better accuracy in recording faces than a standard face-scanning device. Material and Methods In a group of 28 volunteers, two test specimens were attached to their faces: one on their forehead and one turned 90° on their cheek. Each volunteer was scanned by FaceScan3D® and two bundled Artec EVA® scanners. The scans were aligned to a three-dimensional model of the test specimen, and the mean error was recorded. Length, width and angles between the test specimen’s planes were compared. Results The mean deviation is significantly lower for the cheek test specimen in alignment (P < 0.001), length and width (P < 0.001) but not for the forehead test specimen in alignment and length and width (P > 0.05) using FaceScan3D®. The aberration from the original angle between two sides of the test specimen is significantly lower measured with Artec EVA® for the angle between the front and the bottom plane of both test specimens (P < 0.01). Besides the angle between the right plane and the bottom plane as well as the top plane of the test specimen mounted to the cheek, the deviation of the angle between the other side planes to each other is significantly lower (P > 0.05) scanned with Artec EVA®. Conclusions Compared to FaceScan3D®, two bundled Artec EVA® scanners provide different accuracies depending on the location of the measured parameters. The accuracy measured for both scanners is inside the range found in the literature.

Bony contact area and displacement of the temporomandibular joint after high-oblique and bilateral sagittal split osteotomy: a computer-simulated comparison.

The most common way to move the mandible during orthognathic surgery is by bilateral sagittal split osteotomy (BSSO). The high-oblique sagittal split osteotomy (HSSO) is an alternative, although its use is limited by potential complications, mainly to do with the position of the condyle and reduced contact with bone. The aim of this study was to find out the optimal intercondylar distance and area of contact with the surface of the bone for mandibular advancement and setback in BSSO and HSSO. Data from computed tomographic (CT) images from 40 patients were loaded into special planning software, and virtual operations done for mandibular advancement and setback at 3, 5, 8, and 10mm using BSSO and HSSO, which resulted in 640 individual mandibular displacements. The resultant area of bony contact and intercondylar distance were calculated by the software. The mean (SD) areas of contact with the bony surface after 10mm advancement for HSSO and BSSO were 193.94 (63.76) mm(2) and 967.92 (229.21) mm(2), respectively, and after 10mm setback 202.64 (62.30) mm(2) and 1108.86 (247.38) mm(2). The mean corresponding intercondylar distance after maximum advancement were 86.76 (6.40) mm and 86.59 (6.24) mm, and after maximum setback 74.90 (5.73) mm and 73.06 (6.06) mm. There were significant differences between the two for the area of contact with the surface at each displacement distance (p<0.001), but not for intercondylar distance. A larger area of bony contact can be expected at any displacement distance for BSSO, so the changes in intercondylar distance should not be considered when deciding which osteotomy to select.

Introduction of an algorithm for planning of autologous fibular transfer in mandibular reconstruction based on individual bone curvatures

Reconstruction of the mandible with autologous transplants is a challenging task and current computer‐aided surgical planning remains cumbersome. Thus, the aim of the present study was to create an automated computational approach for this procedure.

Three-dimensional evaluation of the posterior airway space: differences in computed tomography and cone beam computed tomography

ObjectivesObstructive sleep apnea syndrome (OSAS) becomes increasingly important. For diagnosis and surgery, computed tomography (CT), and cone beam computed tomography (CB-CT) are used equally, although in most of cases, patient positioning differs between supine positioning (CT) and upright seating positioning (CB-CT). We measured volumetric and anatomical changes in the posterior airway space (PAS) between upright and supine positioning in a three-dimensional set up.Materials and methodsCoherent CT and CB-CT scans of 55 patients were included in the study. Using Brainlab ENT 3.0, image data was superimposed, and three-dimensional models were segmented. PAS height, cross-sectional area, vertical and horizontal position of the mandible and hyoid, and volumetric analyses of the three-dimensional models were measured.ResultsPAS height and cross-sectional area were significantly higher in CB-CT compared to CT scans (p < 0.001). In the vertical dimension, the mandible and hyoid were localized more caudally in CB-CT in contrast to CT scans (p < 0.04; p < 0.001). Three-dimensional evaluation showed a greater volume of the PAS in CB-CT (p < 0.0001). Pearson correlation coefficient showed a correlation between vertical positioning of the mandible and hyoid compared to the positioning of the patient.ConclusionsPatient positioning during CT and CB-CT has an effect on the location of anatomical structures like the mandible and hyoid and changes the dimensions and volume of the posterior airway space significantly.Clinical relevanceThe radiological technique used and the positioning of the patient should be taken into account when considering further surgical therapy.