Search results for "Cone"
showing 10 items of 772 documents
A new 3D method for measuring cranio-facial relationships with cone beam computed tomography (CBCT)
2013
Objectives: CBCT systems, with their high precision 3D reconstructions, 1:1 images and accuracy in locating cephalometric landmarks, allows us to evaluate measurements from craniofacial structures, so enabling us to replace the anthropometric methods or bidimensional methods used until now. The aims are to analyse cranio-facial relationships in a sample of patients who had previously undergone a CBCT and create a new 3D cephalometric method for assessing and measuring patients. Study Design: 90 patients who had a CBCT (i-Cat®) as a diagnostic register were selected. 12 cephalometric landmarks on the three spatial planes (X,Y,Z) were defined and 21 linear measurements were established. Using…
The assesment of relationship between the angulation of impacted mandibular third molar teeth and the thickness of lingual bone: A prospective clinic…
2018
Background Our purpose was to investigate the relationship between the angulation of mandibular third molars and the thickness of the lingual bone, which can affect the risk of lingual nerve damage during lower third molars surgical extraction. Material and Methods This study consisted of 104 patients (42 males and 62 females), aged between 18-42 years (24.67 ± 6.11 years). Cone Beam Computed Tomography (CBCT) images were taken for preoperative assessment. The teeth were divided into four groups according to their positions: mesioangular, distoangular, vertical and horizontal. Lingual bone thickness around impacted teeth were measured at three points: cementoenamel junction (CEJ) of the man…
Cephalometric measurements from 3D reconstructed images compared with conventional 2D images
2011
Abstract Objective: To assess whether the values of different measurements taken on three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) are comparable with those taken on two-dimensional (2D) images from conventional lateral cephalometric radiographs (LCRs) and to examine if there are differences between the different types of CBCT software when taking those measurements. Material and Methods: Eight patients were selected who had both an LRC and a CBCT. The 3D reconstructions of each patient in the CBCT were evaluated using two different software packages, NemoCeph 3D and InVivo5. An observer took 10 angular and 3 linear measurements on each of the three types o…
Goldmann Applanation Tonometry Using Sterile Disposable Silicone Tonometer Shields
1996
Abstract Purpose: Placement of a sterile single-use cover over the tonometer tip may be a convenient and safe alternative method to repeated chemical disinfection. This study was undertaken to evaluate the accuracy and performance of Goldmann applanation tonometry using a sterile disposable silicone tonometer shield over the biprism tip. Methods: The same investigator measured intraocular pressure in 120 eyes with and without the shield. The eyes were tested randomly first with either the uncovered or the covered tonometer to control for the possible effects of repeated tonometry influencing measurement differences. Readings were recorded independently in a masked fashion. Results: The intr…
Use of autologous tooth-derived graft material in the post-extraction dental socket. Pilot study
2019
Background The objectives of the present pilot study are to compare via CBCT the alveolar contraction suffered both vertically and horizontally between the control group and the group using autologous dental material (ADM), as well as to study the densitometric differences between both post-extraction sockets. Material and Methods A split-mouth study was performed in n = 9 patients who required two extraction of single-rooted teeth deemed suitable for deferred rehabilitation with osseointegrated implants. Two groups were formed — a control group, in which the post-extraction socket was not filled, and an ADM group, in which the alveolar defect was filled with freshly processed autogenous de…
Accuracy between virtual surgical planning and actual outcomes in orthognathic surgery by iterative closest point algorithm and color maps: A retrosp…
2018
Background To evaluate the accuracy between actual outcomes and virtual surgical planning (VSP) in orthognathic surgery regarding the use of three-dimensional (3D) surface models for registration using iterative closest point (ICP) algorithm and generated color maps. Material and Methods Construction of planning and postoperative 3D models in STL files format (M0 and M1, respectively) from CBCT of 25 subjects who had been submitted to bimaxillary orthognathic surgery was performed. M0 and M1 were sent to Geomagic software in semi-automatic alignment surface mesh order of M0 and M1 for registration using ICP algorithm to calculate mean deviation (MD, MD+, MD-, SD) and root mean square (RMS –…
Study between anb angle and Wits appraisal in cone beam computed tomography (CBCT)
2013
Objectives: To analyse the ANB and Wits values and to study correlations between those two measurements and other measurements in diagnosing the anteroposterior maxilo-mandibular relationship with CBCT. Study Design: Ninety patients who had previously a CBCT (i-CAT®) as a diagnostic register were selected. A 3D cephalometry was designed using one software package, InVivo5®. This cephalometry included 3 planes of reference, 3 angle measurements and 1 linear measurement. The means and standard deviations of the mean of each measurement were assessed. After that, a Pearson´s correlation coefficient has been performed to analyse the significance of each relationship. Results: When classifying t…
Anatomical characteristics and visibility of mental foramen and accessory mental foramen: Panoramic radiography vs. cone beam CT.
2015
Background: The mental foramen (MF) is a small foramen located in the anterolateral region of the mandible through which the mental nerve and vessels emerge. The knowledge on the anatomic characteristics and variations of MF is very important in surgical procedures involving that area. The aim of this study was two-fold: firstly, to analyze the anatomic characteristics of MF and the presence of accessory mental foramen (AMF) using CBCT and, secondly, to compare the capability of CBCT and PAN in terms of MF and AMF visualization, as well as influencing factors. Material and Methods: A sample of 344 CBCT scans was analyzed for presence and characteristics (i.e. diameter, area, shape, exit ang…
Influence of skeletal class in the morphology of cervical vertebrae: A study using cone beam computed tomography
2016
ABSTRACT Objectives: To quantify the prevalence of cervical vertebrae anomalies and to analyze any association between them and skeletal malocclusions or head posture positions in the same study. Materials and Methods: Two hundred forty patients who were attending the Department of Orthodontics of the University of Valencia for orthodontic treatment were selected and divided into three groups: skeletal Class I (control group, 0° <ANB < 4°), Class II (ANB ≥ 4°), and Class III (ANB ≤ 0°) according to ANB Steiner angle. The morphology of the first five cervical vertebrae was analyzed with cone beam computed tomography to identify any anomalies. Intra- and interobserver error meth…
Analyzing the teeth next to the alveolar cleft: Examination and treatment proposal prior to bone grafting based on three-dimensional versus two-dimen…
2016
Abstract Purpose The objective was to evaluate the diagnostic and prognostic value of three-dimensional (3D) cone beam computed tomography (CBCT) on information about the cleft and alignment of cleft neighboring teeth. Materials and methods Panoramic X-rays, small-volume CBCTs, and study casts of 20 patients with a total of 22 alveolar clefts were analyzed prior to secondary bone grafting. Six maxillofacial surgeons and 6 orthodontists rated the following parameters: visibility of alveolar cleft expansion, position and probability of alignment of cleft neighbored teeth. Two-dimensional (2D) X-rays and casts were rated first; CBCT and casts followed at least 4 weeks later. Radiologic bone he…