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PubMed | Pontifical Catholic University of Parana, University of Leuven and Oral & Maxillofacial Surgery, Hasselt University, University of Sichuan and 2 more.
Type: | Journal: Bone research | Year: 2015

Cone-beam computed tomography (CBCT) has been recently used to analyse trabecular bone structure around dental implants. To validate the use of CBCT for three-dimensional (3D) peri-implant trabecular bone morphometry by comparing it to two-dimensional (2D) histology, 36 alveolar bone samples (with implants n=27 vs. without implants n=9) from six mongrel dogs, were scanned ex vivo using a high-resolution (80 m) CBCT. After scanning, all samples were decalcified and then sectioned into thin histological sections (6 m) to obtain high contrast 2D images. By using CTAn imaging software, bone morphometric parameters including trabecular number (Tb.N), thickness (Tb.Th), separation (Tb.Sp) and bone volume fraction (BV/TV) were examined on both CBCT and corresponding histological images. Higher Tb.Th and Tb.Sp, lower BV/TV and Tb.N were found on CBCT images (P<0.001). Both measurements on the peri-implant trabecular bone structure showed moderate to high correlation (r=0.65-0.85). The Bland-Altman plots showed strongest agreement for Tb.Th followed by Tb.Sp, Tb.N and BV/TV, regardless of the presence of implants. The current findings support the assumption that peri-implant trabecular bone structures based on high-resolution CBCT measurements are representative for the underlying histological bone characteristics, indicating a potential clinical diagnostic use of CBCT-based peri-implant bone morphometric characterisation.

PubMed | Eastman Dental Hospital, Copenhagen University, University of Zürich, Trinity College Dublin and 5 more.
Type: | Journal: Clinical oral implants research | Year: 2015

The task of this working group was to assess the existing knowledge in computer-assisted implant planning and placement, fabrication of reconstructions applying computers compared to traditional fabrication, and assessments of treatment outcomes using novel imaging techniques.Three reviews were available for assessing the current literature and provided the basis for the discussions and the consensus report. One review dealt with the use of computers to plan implant therapy and to place implants in partially and fully edentulous patients. A second one focused on novel techniques and methods to assess treatment outcomes and the third compared CAD/CAM-fabricated reconstructions to conventionally fabricated ones.The consensus statements, the clinical recommendations, and the implications for research, all of them after approval by the plenum of the consensus conference, are described in this article. The three articles by Vercruyssen et al., Patzelt & Kohal, and Benic et al. are presented separately as part of the supplement of this consensus conference.

PubMed | Health Science University, Catholic University of Louvain, Hasselt University, University of Leuven and Oral & Maxillofacial Surgery and Center Hospitalier Regional dOrleans
Type: Journal Article | Journal: European journal of orthodontics | Year: 2015

To develop a novel 3D landmark reference system that is specific for mandibular midline cephalometric landmarks and to assess its repeatability and reproducibility.Cone-beam computed tomography (CBCT) scans (3D Accuitomo 170) were performed on 26 dry human skulls. The CBCT data were exported into DICOM files and imported to Maxilim software to create 3D surface models. Two observers identified five landmarks to create a specific mid-sagittal mandibular plane: two mandibular foramina, two molar landmarks and one interincisive landmark. On this mid-sagittal mandibular plane, four mandibular cephalometric landmarks were marked: Point B, Pogonion, Gnathion and Menton. All observations were repeated by the two observers after an interval of 4 weeks. The coordinates (x, y, z) of each landmark were exported, and statistical analyses were performed to evaluate inter- and intra-rater precision.The intra-observer median precision in locating all landmarks ranged between 0.17 and 0.61mm. The intra-observer repeatability was generally good with a precision under 1mm in more than 50 per cent. The overall median inter-observer precision was 0.26-2.30mm. The mandibular foramina showed the best inter-observer reproducibility. The general inter-observer reproducibility was moderate to good, except for Pogonion and Point B.Dry human skulls may not represent anatomical conditions found in living patients, thus the system should be validated using patients data.The novel reference system offered good precision and generally good to moderate repeatability and reproducibility for mandibular midline cephalometric landmark identification in three dimensions. These findings will be useful for further improvement of 3D cephalometric systems.

PubMed | University of Leuven and Oral & Maxillofacial Surgery, Hasselt University, Scientific Institute of Public Health, Chulalongkorn University and 2 more.
Type: Comparative Study | Journal: European journal of orthodontics | Year: 2015

The aim of this study was to evaluate the accuracy of linear measurements on three imaging modalities: lateral cephalograms from a cephalometric machine with a 3 m source-to-mid-sagittal-plane distance (SMD), from a machine with 1.5 m SMD and 3D models from cone-beam computed tomography (CBCT) data.Twenty-one dry human skulls were used. Lateral cephalograms were taken, using two cephalometric devices: one with a 3 m SMD and one with a 1.5 m SMD. CBCT scans were taken by 3D Accuitomo 170, and 3D surface models were created in Maxilim software. Thirteen linear measurements were completed twice by two observers with a 4 week interval. Direct physical measurements by a digital calliper were defined as the gold standard. Statistical analysis was performed.Nasion-Point A was significantly different from the gold standard in all methods. More statistically significant differences were found on the measurements of the 3 m SMD cephalograms in comparison to the other methods. Intra- and inter-observer agreement based on 3D measurements was slightly better than others.Dry human skulls without soft tissues were used. Therefore, the results have to be interpreted with caution, as they do not fully represent clinical conditions.3D measurements resulted in a better observer agreement. The accuracy of the measurements based on CBCT and 1.5 m SMD cephalogram was better than a 3 m SMD cephalogram. These findings demonstrated the linear measurements accuracy and reliability of 3D measurements based on CBCT data when compared to 2D techniques. Future studies should focus on the implementation of 3D cephalometry in clinical practice.

PubMed | University of Leuven and Oral & Maxillofacial Surgery, Hasselt University and University of Campinas
Type: Journal Article | Journal: International endodontic journal | Year: 2015

To evaluate the characteristic artefact patterns associated with teeth root filled with Gutta-percha when scanned with four cone-beam CT devices.Whilst using soft tissue simulation, ten root filled human premolars were placed in empty sockets in a dry human skull. Subsequently, the skull was scanned using 3D Accuitomo 170() , WhiteFox() , Cranex 3D() and Scanora 3D() following clinical protocols with the highest resolution and artefact reduction. After proper image registration in OnDemand3D() software (Cybermed, Seoul, Korea), each image slice was evaluated by three trained and calibrated dentomaxillofacial radiologists, which scored absence (0) and presence (1) of cupping artefact, hypodense halos and streak artefacts. Kappa test was performed for intra- and interobserver agreement.A moderate to perfect agreement for each observer (intra-observer = 0.5-1.0) was found. Agreement between the different observers was moderate to almost perfect for the different artefact patterns (interobserver = 0.55-0.9). Cupping artefact was the most prevalent (70%), followed by a hypodense halo (35%) and streak artefacts (16%). The Chi-squared test revealed significantly more streaks in axial slices (P < 0.0001), with some CBCT systems yielding significantly inferior results to others (P < 0.05). The dedicated EndoMode and artefact reduction did not improve the result significantly.The variation of artefact expression was significantly different amongst CBCT machines for root filled teeth. Continuous efforts are needed to improve CBCT reconstruction algorithms, with a specific focus on reducing artefacts induced by dense dental materials, whilst striving for enhanced image quality at low-radiation doses.

PubMed | University of Leuven and Oral & Maxillofacial Surgery and Hasselt University
Type: Journal Article | Journal: Clinical oral implants research | Year: 2015

To systematically review the available literature on the influence of dental implant placement and loading protocols on peri-implant innervation.The database MEDLINE, Cochrane, EMBASE, Web of Science, LILACS, OpenGrey and hand searching were used to identify the studies published up to July 2013, with a populations, exposures and outcomes (PEO) search strategy using MeSH keywords, focusing on the question: Is there, and if so, what is the effect of time between tooth extraction and implant placement or implant loading on neural fibre content in the peri-implant hard and soft tissues?Of 683 titles retrieved based on the standardized search strategy, only 10 articles fulfilled the inclusion criteria, five evaluating the innervation of peri-implant epithelium, five elucidating the sensory function in peri-implant bone. Three included studies were considered having a methodology of medium quality and the rest were at low quality. All those papers reported a sensory innervation around osseointegrated implants, either in the bone-implant interface or peri-implant epithelium, which expressed a particular innervation pattern. Compared to unloaded implants or extraction sites without implantation, a significant higher density of nerve fibres around loaded dental implants was confirmed.To date, the published literature describes peri-implant innervation with a distinct pattern in hard and soft tissues. Implant loading seems to increase the density of nerve fibres in peri-implant tissues, with insufficient evidence to distinguish between the innervation patterns following immediate and delayed implant placement and loading protocols. Variability in study design and loading protocols across the literature and a high risk of bias in the studies included may contribute to this inconsistency, revealing the need for more uniformity in reporting, randomized controlled trials, longer observation periods and standardization of protocols.

PubMed | Catholic University of Leuven and University of Leuven and Oral & Maxillofacial Surgery
Type: | Journal: Clinical oral implants research | Year: 2015

To give an overview of the workflow from examination to planning and execution, including possible errors and pitfalls, in order to justify the indications for guided surgery.An electronic literature search of the PubMed database was performed with the intention of collecting relevant information on computer-supported implant planning and guided surgery.Currently, different computer-supported systems are available to optimize and facilitate implant surgery. The transfer of the implant planning (in a software program) to the operative field remains however the most difficult part. Guided implant surgery clearly reduces the inaccuracy, defined as the deviation between the planned and the final position of the implant in the mouth. It might be recommended for the following clinical indications: need for minimal invasive surgery, optimization of implant planning and positioning (i.e. aesthetic cases), and immediate restoration.The digital technology rapidly evolves and new developments have resulted in further improvement of the accuracy. Future developments include the reduction of the number of steps needed from the preoperative examination of the patient to the actual execution of the guided surgery. The latter will become easier with the implementation of optical scans and 3D-printing.

PubMed | Catholic University of Leuven and University of Leuven and Oral & Maxillofacial Surgery
Type: Journal Article | Journal: Clinical oral implants research | Year: 2016

To assess the accuracy and patient-centered outcome of a novel guided surgery system for placing implants in an edentulous maxilla.Fifteen consecutive patients with sufficient bone to place six implants in the maxilla were randomly assigned to the immediate loading (with delivery of the final prosthesis within 24 h) or the delayed loading treatment group. Accuracy was assessed by matching the planning CT with a postoperative CBCT. Patient-centered outcome measures were the Dutch version of the McGill Pain Questionnaire (MPQ-DLV), the health-related quality of life instrument (HRQOL), visual analog scales (VAS), the duration of the procedure, and the analgesic doses taken each day.A mean deviation was found at the entry point of 0.9 mm (range: 0.1-4.5, median 0.8) and of 1.2 mm (range: 0.2-4.9, median 1.1) at the apex, and an angular deviation of 2.7 (range: 0.0-6.6, median 2.3) was observed. The mean vertical deviation was 0.5 mm (range: 0.0-3.2, median 0.4), and in a horizontal direction, this was 0.7 mm (range: 0.1-3.1, median 0.6). The mean deviation in mesio-distal direction was 0.5 mm (range: 0.0-2.3, median 0.4) and in bucco-lingual direction 0.5 mm 0.4 (range: 0.0-2.2, median 0.3). No statistical differences could be shown between treatment groups on pain response (MPQ-DLV), treatment perception (VAS), number or kind of pain killers, or for the HRQOLI instrument.The accuracy of a novel CT-based guide is comparable to the accuracy data of other systems. Within the limitations of this study, no difference could be found in patient-centered outcome variables after immediate or delayed loading.

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