No evidence for long-term effectiveness of early osteodistraction in hemifacial microsomia.

Contains fulltext : 81266.pdf (publisher's version ) (Closed access)BACKGROUND: The authors performed a critical literature review to find evidence of the long-term stability after early distraction osteogenesis of the mandible in patients with hemifacial microsomia. METHODS: The PubMed, Cochrane, MEDLINE, EMBASE, CENTRAL, and CINAHL databases were searched systematically for studies performed between 2002 and 2008. Abstracts from the 89 relevant articles were reviewed for evidence. RESULTS: Thirteen articles met the inclusion criteria. Data were tabulated with respect to the length of follow-up, number of patients, age group, Pruzansky-Kaban classification of the patients, methods of analysis and validation, and level of evidence. Methods for long-term follow-up studies were not standardized, and no objective studies have been published on stability after growth cessation. CONCLUSIONS: Thus far, no randomized controlled trials on early distraction osteogenesis in hemifacial microsomia patients have been published. The authors conclude that there is a lack of statistical evidence to support the use of early distraction osteogenesis for correcting hemifacial microsomia as a single treatment modality. The results call into question its rationale

Nasal profile changes after maxillary impaction and advancement surgery

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Creating a normative database of age-specific 3D geometrical data, bone density, and bone thickness of the developing skull: a pilot study

OBJECT Finite element models (FEMs) of the head are used to study the biomechanics of traumatic brain injury and depend heavily on the use of accurate material properties and head geometry. Any FEM aimed at investigating traumatic head injury in children should therefore use age-specific dimensions of the head, as well as age-specific material properties of the different tissues. In this study, the authors built a database of age-corrected skull geometry, skull thickness, and bone density of the developing skull to aid in the development of an age-specific FEM of a child's head. Such a database, containing age-corrected normative skull geometry data, can also be used for preoperative surgical planning and postoperative long-term follow-up of craniosynostosis surgery results. METHODS Computed tomography data were processed for 187 patients (age range 0-20 years old). A 3D surface model was calculated from segmented skull surfaces. Skull models, reference points, and sutures were processed into a MATLAB-supported database. This process included automatic calculation of 2D measurements as well as 3D measurements: length of the coronal suture, length of the lambdoid suture, and the 3D anterior-posterior length, defined as the sum of the metopic and sagittal suture. Skull thickness and skull bone density calculations were included. RESULTS Cephalic length, cephalic width, intercoronal distance, lateral orbital distance, intertemporal distance, and 3D measurements were obtained, confirming the well-established general growth pattern of the skull. Skull thickness increases rapidly in the first year of life, slowing down during the second year of life, while skull density increases with a fast but steady pace during the first 3 years of life. Both skull thickness and density continue to increase up to adulthood. CONCLUSIONS This is the first report of normative data on 2D and 3D measurements, skull bone thickness, and skull bone density for children aged 0-20 years. This database can help build an age-specific FEM of a child's head. It can also help to tailor preoperative virtual planning in craniosynostosis surgery toward patient-specific normative target values and to perform objective long-term follow-up in craniosynostosis surgery

A systematic review of the effects of bone-borne surgical assisted rapid maxillary expansion.

Contains fulltext : 87283.pdf (publisher's version ) (Closed access)INTRODUCTION: A systematic literature review was conducted to find out if bone-borne maxillary expansion with corticotomies is an effective and secure orthodontic/orthopaedic treatment modality, eliminating orthodontic and periodontal side effects of tooth-borne maxillary expansion with corticotomies. MATERIAL AND METHODS: Randomized controlled trials (RCT), controlled clinical trials (CCT) and case series with a sample size >or=5 were electronically searched in PubMED, MEDLINE, EMBASE Excerpta Medica, CINAHL, Biological Abstracts and CENTRAL till June 2008. Data were extracted by 2 observers. RESULTS: Ten studies fulfilled the inclusion criteria, of which 9 were prospective and 1 was a retrospective case series. CONCLUSION: No RCT's or CCT's were published on bone-borne surgically assisted rapid maxillary expansion (SARME). For expected advantages compared to tooth-borne SARME, only weak evidence was found for less buccal tipping of the teeth used as anchor teeth in tooth-borne expansion. The heterogeneity of the retrieved publications and the wide variety of outcome variables posed serious restrictions on the review of the literature in a quantitative systematic manner. There is a need for well designed clinical trials research on the effects of tooth-borne and bone-borne SARME.01 april 201

Accuracy and repeatability of cone-beam computed tomography (CBCT) measurements used in the determination of facial indices in the laboratory setup.

Item does not contain fulltextAIM: To assess the three dimensional (3D) surface accuracy of a phantom's face acquired from a cone-beam computed tomography (CBCT) scan and to determine the reliability of selected cephalometric measurements performed with Maxilim software (Medicim N.V., Mechelen, Belgium). MATERIAL AND METHODS: A mannequin head was imaged with a CBCT (I-CAT, Imaging Sciences International, Inc., Hatfield, USA). The data were used to produce 3D surface meshes (Maxilim and Mimics, Materialise N.V., Leuven, Belgium) which were compared with an optical surface scan of the head using Focus Inspection software (Metris N.V., Leuven, Belgium). The intra- and inter-observer reliability for the measurement of distances between facial landmarks with Maxilim 3D cephalometry were determined by calculating Pearson correlation coefficients and intraclass correlation (ICC). The Dahlberg formula was used to assess the method error (ME). RESULTS: (1) The maximal range of the 3D mesh deviations was 1.9 mm for Maxilim, and 1.8mm for Mimics segmentation. (2) Test-retest and inter-observer reliability were high; Pearson's correlation coefficient was 1.000 and the ICC was 0.9998. The ME of the vertical measurements was a little larger than that calculated for the width measurements. Maximum ME was 1.33 mm. CONCLUSIONS: The 3D surface accuracy of CBCT scans segmented with Maxilim and Mimics software is high. Maxilim also shows satisfactory intra- and inter-assessor reliability for measurement of distances on a rigid facial surface

A cone-beam CT based technique to augment the 3D virtual skull model with a detailed dental surface.

Item does not contain fulltextCone-beam computed tomography (CBCT) is used for maxillofacial imaging. 3D virtual planning of orthognathic and facial orthomorphic surgery requires detailed visualisation of the interocclusal relationship. This study aimed to introduce and evaluate the use of a double CBCT scan procedure with a modified wax bite wafer to augment the 3D virtual skull model with a detailed dental surface. The impressions of the dental arches and the wax bite wafer were scanned for ten patient separately using a high resolution standardized CBCT scanning protocol. Surface-based rigid registration using ICP (iterative closest points) was used to fit the virtual models on the wax bite wafer. Automatic rigid point-based registration of the wax bite wafer on the patient scan was performed to implement the digital virtual dental arches into the patient's skull model. Probability error histograms showed errors of < or =0.22 mm (25% percentile), < or =0.44 mm (50% percentile) and < or =1.09 mm (90% percentile) for ICP surface matching. The mean registration error for automatic point-based rigid registration was 0.18+/-0.10 mm (range 0.13-0.26 mm). The results show the potential for a double CBCT scan procedure with a modified wax bite wafer to set-up a 3D virtual augmented model of the skull with detailed dental surface