Thirty Years of Pancreas Transplantation at Leiden University Medical Center: Long-term Follow-up in a Large Eurotransplant Center

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Gram-positive anaerobe <i>cocci </i>(GPAC) are underrepresented in the microbiome of filaggrin-deficient human skin

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In dienst van de dialectwetenschap. In memoriam prof. dr. A. Weijnen

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[Clinical results of bone anchors for orthodontic anchorage; the indications and surgical complications],[Clinical results of bone anchors for orthodontic anchorage; the indications and surgical complications]

Contains fulltext : 79819.pdf (publisher's version ) (Open Access)In order to make teeth-movement possible, orthodontic anchorage is necessary. Neighbouring teeth, a headgear, dental implants and bone anchors can be used. During the period 2002-2007 158 bone anchors have been placed in 84 patients by an oral surgeon after referral by an orthodontist in order to achieve anchorage for orthodontic treatment. The bone anchor consists of a titanium osteosynthesis-plate ending in a round neck perforating the soft tissue and a cylinder attached to it. The indications for placement, results and complications were registered. 15 anchors (9,5%) were lost prematurely and in 13 cases (8,2%) complications needing surgical intervention were reported. It is concluded that zygoma-bone anchor is a good alternative for orthodontic anchorage and the number of complications is acceptable, though there is room for improvement

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

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Pathologies de surcharge spécifiques à l'escalade sportive

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

[Clinical results of bone anchors for orthodontic anchorage; the indications and surgical complications]

In order to make teeth-movement possible, orthodontic anchorage is necessary. Neighbouring teeth, a headgear, dental implants and bone anchors can be used. During the period 2002-2007 158 bone anchors have been placed in 84 patients by an oral surgeon after referral by an orthodontist in order to achieve anchorage for orthodontic treatment. The bone anchor consists of a titanium osteosynthesis-plate ending in a round neck perforating the soft tissue and a cylinder attached to it. The indications for placement, results and complications were registered. 15 anchors (9,5%) were lost prematurely and in 13 cases (8,2%) complications needing surgical intervention were reported. It is concluded that zygoma-bone anchor is a good alternative for orthodontic anchorage and the number of complications is acceptable, though there is room for improvement

Three-dimensional evaluation of the alar cinch suture after Le Fort I osteotomy

Orthognathic surgery has an influence on the overlying soft tissues of the translated bony maxillomandibular complex. Improvements in both function and facial appearance are the goals of surgery. However, unwanted changes to the soft tissues, especially in the nose region, frequently occur. The most common secondary change in the nasolabial region is widening of the alar base. Various surgical techniques have been developed to minimize this effect. The purpose of this study was to evaluate the changes in the nasal region due to orthognathic surgery, especially the alar width and nasal volume, using combined cone beam computed tomography (CBCT) and three-dimensional (3D) stereophotogrammetry datasets. Twenty-six patients who underwent a Le Fort I advancement osteotomy between 2006 and 2013 were included. From 2006 to 2010, no alar base cinch sutures were performed. From 2010 onwards, alar base cinch sutures were used. Preoperative and postoperative documentation consisted of 3D stereophotogrammetry and CBCT scans. 3D measurements were performed on the combined datasets, and the alar base width and nose volume were analyzed. No difference in alar base width or nose volume was observed between patients who had undergone an alar cinch and those who had not. Postoperatively the nose widened and the volume increased in both groups

Factors limiting maximal performance in humans

The purpose of this study was to evaluate the accuracy of an algorithm based on the mass tensor model (MTM) for computerized 3D simulation of soft-tissue changes following bimaxillary osteotomy, and to identify patient and surgery-related factors that may affect the accuracy of the simulation. Sixty patients (mean age 26.0 years) who had undergone bimaxillary osteotomy, participated in this study. Cone beam CT scans were acquired pre- and one year postoperatively. The 3D rendered pre- and postoperative scans were matched. The maxilla and mandible were segmented and aligned to the postoperative position. 3D distance maps and cephalometric analyses were used to quantify the simulation error. The mean absolute error between the 3D simulation and the actual postoperative facial profile was 0.81 +/- 0.22 mm for the face as a whole. The accuracy of the simulation (average absolute error </=2 mm) for the whole face and for the upper lip, lower lip and chin subregions were 100%, 93%, 90% and 95%, respectively. The predictability was correlated with the magnitude of the maxillary and mandibular advancement, age and V-Y closure. It was concluded that the MTM-based soft tissue simulation for bimaxillary surgery was accurate for clinical use, though patients should be informed of possible variation in the predicted lip position

A new 3D approach to evaluate facial profile changes following BSSO

The purpose of this study was to evaluate changes in the soft tissue facial profile in patients who underwent bilateral sagittal split osteotomy (BSSO) using 3D stereophotogrammetry and principal component analysis (PCA). Twenty-five female patients (mean age, 24 years; range: 18-26) who underwent BSSO and 70 female controls (mean age, 24 years; range: 18-26) participated in this prospective study. Three-dimensional photographs of all patients and controls were acquired. PCA was used to determine the unique morphological variations (UV) between the dysgnathic group and the control group. The most prominent facial morphologic difference between the dysgnathic group and the control group (UV1) was a clockwise rotation of the mandible and shortening of the lower part of the face, followed by a protrusion of the upper lip, retrusion of the mandible and over-accentuation of the labial-mental fold (UV2). The combination of UV1 and UV2 could be used to simulate a typical Class II facial profile and to automatically differentiate between the preoperative patients, postoperative patients and the control group. Based on the applied PCA method, this study demonstrated that BSSO advancement surgery could only provide a suboptimal improvement of the soft tissue facial profile in the majority of cases