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Aging of Skin, Soft Tissue, and Bone
Published in Ali Pirayesh, Dario Bertossi, Izolda Heydenrych, Aesthetic Facial Anatomy Essentials for Injections, 2020
Daria Voropai, Steven Dayan, Luis Fernando Botero, Chiara Botti, Leonard Miller, Ali Pirayesh
The important aesthetic landmark of the upper third is the nasion, defined as the suture between the frontal and nasal bones in the midsagittal plane. Together with the nasion, the glabellar angle (the line connecting the maximal glabellar prominence with the nasofrontal suture, as compared to the horizontal or nasal-sellar line) is used as an anthropometric measurement in facial and cephalometric analysis.
Formation of the Cranial Base and Craniofacial Joints
Published in D. Dixon Andrew, A.N. Hoyte David, Ronning Olli, Fundamentals of Craniofacial Growth, 2017
Kvinnsland (1971) also made 4 different linear measurements of the cranial base in his collection of 159 human embryos, finding that the anterior segment, i.e., anterior border of the cribriform plate to sella (acbp-s), grew 22 mm between 20 mm and 82 mm HL, compared to 13 mm growth in the posterior segment. This matched results obtained by other investigators, that there are larger increases in the anterior part of the cranial base (Levihn, 1967; Houpt, 1970). Cephalometric analysis of craniofacial proportions in human fetuses 12-25 weeks old showed that the face and anterior cranial base grew proportionally, but not the posterior cranial base, where growth was slower (Johnston, 1974). He postulated that the predominance of endochondral ossification in the posterior cranial base during the second, trimester, in contrast to the interstitial expansion of cartilage that governed the growth of the anterior cranial base during the same time frame, could explain the difference in growth rates.
Skeletal-versus soft-tissue-based cephalometric analyses: is the correlation reproducible?
Published in Acta Odontologica Scandinavica, 2019
Oliver Ploder, Robert Köhnke, Heinz Winsauer, Carolin Götz, Oliver Bissinger, Bernhard Haller, Andreas Kolk
Cephalometric analysis (CA) of dentofacial deformities is an important part of the preparation for orthodontic and orthognathic treatment [1]. Numerous variations of CA have been developed in an attempt to define the direction of treatment more objectively [2,3]. Two methods can be distinguished: skeletal and soft tissue CA. Skeletal cephalometric analysis (SKCA) is based on cranial base structures, e.g. the Nasion Sella line (NSL), and emphasis is placed on measurements of skeletal and dental structures within the head films (Figures 1 and 2). Measurements of distances, angles, or ratios between anatomical landmarks (e.g. NSL-A) have been used to objectify the amount of deviation proportionately to standard values [1,3]. Several authors have questioned the validity of these measurements because of their variability and therefore low reliability [4,5]. A variation of the corresponding skeletal structures by up to 20° is described if the cranial base is employed as a reference [6]. Use of various intracranial orientation planes can sometimes lead to completely different findings in the same patient [4,6]. In cases of the obvious deviation of skull base structures, lateral cephalograms need to be re-oriented relative to a horizontal reference plane, and angular and linear measurements from skull base structures to landmarks have to be adapted to this position [7,8]. As a horizontal reference plane, the Frankfurt horizontal (FH) is frequently used for head orientation in CA [9]. However, various authors have questioned the validity of this line, because of the large variation to natural head posture [9–12].
An integrated haptic-enabled virtual reality system for orthognathic surgery planning
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Jorge Zaragoza-Siqueiros, Hugo I. Medellin-Castillo, Héctor de la Garza-Camargo, Theodore Lim, James M. Ritchie
Orthognathic surgery (OGS) is a medical procedure aiming to correct jaw miss-alignment and dentofacial deformities (Posnick 2013). It requires a precise pre-surgical planning to generate the surgical information needed in the operating room and achieve the desired surgical outcomes. Traditionally, the conventional OGS planning process comprises four steps: Clinical facial analysis. Conducted on the patient’s frontal and lateral face photographs. By means of the facial analysis, the surgeon determines a preliminary diagnosis and treatment, i.e. orthodontic or surgical treatment.Cephalometric analysis. To confirm the previous diagnosis and treatment, a cephalometric analysis is carried out on a lateral patient’s skull radiography. The cephalometric values are compared with pre-established standards to determine a final diagnosis and treatment.Model surgery. When a surgical treatment is needed, model surgery allows surgeons to correct the maxillary misalignment by using the patient’s dental cast models, which are mounted on an articulator to simulate the patient's maxillary and mandibular position. On the articulator, the dental casts are manually segmented and repositioned to achieve the desired patient’s occlusion.Surgical template generation. Once the desired maxillary position is obtained, the new patient’s occlusion is recorded manually on an acrylic surgical template (also known as wafer), enabling surgeons to transfer the surgical planning outcomes to the operating room.