Sella Point Research Articles

Cephalometric analysis of traditional and new Sella point

Cephalometric analysis of traditional and new Sella point

Sella Turcica Bridging and its Association with Dental Anomalies - An Update

: The Sella turcica is an anatomical structure shaped explicitly like a saddle, located within the middle cranial fossa on the intracranial surface of the sphenoid bone. This structure is commonly observed on lateral cephalograms, frequently employed for orthodontic diagnosis. The Cephalometric radiographs utilize various landmarks as reference points to examine craniofacial structures and Sella Turcica (ST) is the most significant and reliable cranial landmark. The Sella point, located at the midpoint of the ST structure, is a cranial base point that accommodates the pituitary gland. The cephalometric analysis relies on this factor to identify pituitary gland-related pathologies, making it a valuable source of information for craniofacial syndromes. Facial structure development exhibits comparable characteristics to the Sella turcica. Glandular abnormalities possess the potential to be linked to functional disorders, which can result in altered hormonal levels affecting dental growth. Comprehensive understanding of the radiological anatomy and variations help assess growth and identify changes in various anomalies or pathological conditions. Additionally, it can assist in predicting the potential outcome of orthodontic treatment. The objective of this review is to determine and update whether a correlation exists between the bridging of Sella turcica and various dental anomalies related to the shape, size, structure, number, and eruption of teeth. In conclusion, it was noted that Sella turcica bridging is frequently observed in orthodontic patients measuring a clear correlation between dental anomalies and Sella bridging. Key words: Sella Turcica Bridging; Dental Anomalies; Genetics; Lateral Cephalogram; Orthodontist.

Clinical finite element analysis of mandibular displacement model treated with Twin-block appliance

The mechanical distribution of the mandible is an important factor that affects functional orthosis during Twin-block (TB) appliance correction. Changes in the mandible before and after TB appliance correction are also key factors in maintaining the therapeutic effect. Finite element analysis, a powerful numerical, analytical tool, is widely used to predict the stress and strain distribution of the craniofacial bone that orthodontics generates. The sample was a 14-year-old male patient with Class II malocclusion during growth. A cone-beam computed tomography scan was undertaken at pretreatment and posttreatment. In the Finite element analysis of the pretreatment model, the remote displacement model of the mandible was established with the sella point as the center. A mandibular model under TB appliance loading was established. Its mandibular displacement and von Mises stress were compared before and after loading. Three-dimensional registration was conducted on the pretreatment and posttreatment models to measure the sagittal displacement of the centrosome. The force on the mandible occurred mainly in the condyle neck and medial mandible after the TB appliance moved the mandible. After displacement, the posterior upper margin of the condyle was farther away from the articular fossa. Three-dimensional registration results showed that new bone had formed behind and above the condyle after TB appliance treatment. The TB appliance provides additional advantages in treating skeletal Class II malocclusions by helping to reduce the burden on the temporomandibular joint and promoting the adaptive reconstruction of the mandible.

Convolutional Neural Network Performance for Sella Turcica Segmentation and Classification Using CBCT Images.

The present study aims to validate the diagnostic performance and evaluate the reliability of an artificial intelligence system based on the convolutional neural network method for the morphological classification of sella turcica in CBCT (cone-beam computed tomography) images. In this retrospective study, sella segmentation and classification models (CranioCatch, Eskisehir, Türkiye) were applied to sagittal slices of CBCT images, using PyTorch supported by U-Net and TensorFlow 1, and we implemented the GoogleNet Inception V3 algorithm. The AI models achieved successful results for sella turcica segmentation of CBCT images based on the deep learning models. The sensitivity, precision, and F-measure values were 1.0, 1.0, and 1.0, respectively, for segmentation of sella turcica in sagittal slices of CBCT images. The sensitivity, precision, accuracy, and F1-score were 1.0, 0.95, 0.98, and 0.84, respectively, for sella-turcica-flattened classification; 0.95, 0.83, 0.92, and 0.88, respectively, for sella-turcica-oval classification; 0.75, 0.94, 0.90, and 0.83, respectively, for sella-turcica-round classification. It is predicted that detecting anatomical landmarks with orthodontic importance, such as the sella point, with artificial intelligence algorithms will save time for orthodontists and facilitate diagnosis.

Performance of a Convolutional Neural Network- Based Artificial Intelligence Algorithm for Automatic Cephalometric Landmark Detection.

The aim of this study is to develop an artificial intelligence model to detect cephalometric landmark automatically en- abling the automatic analysis of cephalometric radiographs which have a very important place in dental practice and is used routinely in the diagnosis and treatment of dental and skeletal disorders. In this study, 1620 lateral cephalograms were obtained and 21 landmarks were included. The coordinates of all landmarks in the 1620 films were obtained to establish a labeled data set: 1360 were used as a training set, 140 as a validation set, and 180 as a testing set. A convolutional neural network-based artificial intelligence algorithm for automatic cephalometric landmark detection was developed. Mean radial error and success detection rate within the range of 2 mm, 2.5 mm, 3 mm, and 4 mm were used to eval- uate the performance of the model. Presented artificial intelligence system (CranioCatch, Eskişehir, Turkey) could detect 21 anatomic landmarks in a lateral ceph- alometric radiograph. The highest success detection rate scores of 2 mm, 2.5 mm, 3 mm, and 4 mm were obtained from the sella point as 98.3, 99.4, 99.4, and 99.4, respectively. The mean radial error ± standard deviation value of the sella point was found as 0.616 ± 0.43. The lowest success detection rate scores of 2 mm, 2.5 mm, 3 mm, and 4 mm were obtained from the Gonion point as 48.3, 62.8, 73.9, and 87.2, respectively. The mean radial error ± standard deviation value of Gonion point was found as 8.304 ± 2.98. Although the success of the automatic landmark detection using the developed artificial intelligence model was not in- sufficient for clinical use, artificial intelligence-based cephalometric analysis systems seem promising to cephalometric analysis which provides a basis for diagnosis, treatment planning, and following-up in clinical orthodontics practice.

Three-dimensional changes of oropharyngeal airway after orthodontic extraction treatment in skeletal class Ⅰ adolescents

Objective: To explore the effect of extraction on upper airway in skeletal class Ⅰ adolescents. Methods: According to random number table method, 30 skeletal class Ⅰteenagers who underwent orthodontic straight wire treatment were selected randomly in Department of Orthodontics, School of Stomatology, The Fourth Military Medical University between January 2016 and December 2019. There were 13 males and 17 females, aged (13.7±1.5) years (12.2-15.7 years). In all patients, four first premolars were removed and the upper and lower anterior teeth were retracted under non-maximal anchorage (non-implant anchorage or face bow). The cone-beam CT (CBCT) data before and after orthodontic extraction treatments were studied. The three-dimensional model of the upper airway was reconstructed and segmented, and the relevant indexes of oropharyngeal volume and cross-sectional area were measured. Cephalograms was generated to measure tooth-jaw indexes and hyoid position. The changes of each index before and after orthodontic treatment were compared. The correlation between the changes in the volume or sectional area of the oropharyngeal airway and the changes in the dental and maxillary indexes and the hyoid position was tested. Results: Compared with those before treatment, palatopharyngeal volume, glossopharyngeal volume, oropharyngeal total volume, and minimum transection area increased by 632 (558) mm3, 758 (549) mm3, 1 454 (955) mm3 and 14 (29) mm2 respectively, and statistically significant differences were found (P<0.05). The minimum oropharyngeal area was mostly located in the glossopharynx. The cross-sectional area and the maximum anterior-posterior diameter of uvula tip decreased by (4±10) mm2 and (0.4±0.8) mm respectively, and the difference was statistically significant (P<0.05). There was no significant difference in the maximum lateral diameter before and after treatment (P>0.05). The ratio of the maximum antero-posterior diameter to the maximum lateral diameter at the uvula tip decreased from 0.589 (0.034) before treatment to 0.535 (0.047) after treatment (P<0.05), indicating that its shape tends to be more elliptic after treatment. In addition, the change of cross-sectional area at the apex of uvula was positively correlated with the changes of mandibular central incisor lip inclination and the distances from the upper and lower central incisor points to the Frankfort plane perpendicular to the sella point (UI-FHp and LI-FHp) (P<0.05). Conclusions: The impact of orthodontic extraction treatment on oropharyngeal airway was generally small in skeletal class Ⅰ adolescents. However, it could change the shape of the airway to some extent. The change of airway cross-sectional area at the uvula tip was positively correlated with the retraction of anterior teeth.

LE FORT I OSTEOTOMİSİNDE İKİ PLAK İLE MAKSİLLER FİKSASYON YÖNTEMİ :TEKNİK RAPOR VE VAKA SUNUMU

Restoring facial esthetics and occlusion while maintaining long term stability are the goals of orthognathic surgery. Le Fort I osteotomy is frequently used for the correction of dentofacial deformities and is accepted as a relatively stable procedure. Many factors affecting the stability of the mobilized maxilla have been reported. Among these, the use of a stable internal fixation method is of primary importance to postoperative stability. Most oral and maxillofacial surgeons prefer bilaterally applying titanium miniplates in both the anterior apertura piriformis region and the posterior zygomaticomaxillary buttress region to achieve the rigid fixation of the maxillary segment following Le Fort I osteotomy. In the literature, there is currently a lack of agreement on the number of plates required to adequately secure the mobilized maxilla to prevent postoperative relapse. Reducing the number of miniplates allows surgeons to reduce any potential complications, operation time, and costs. In this case report, a patient with maxillary retrognathia and mandibular prognathia, manifesting dental Class III characteristics who underwent one piece Le Fort I osteotomy at Baskent University Faculty of Dentistry, Department of Oral and Maxillofacial Surgery was presented. Under general anesthesia one piece Le Fort I osteotomy was performed. Following down fracture, mobilization of the maxillary segment was completed and 10 mm horizontal advancement movement was achieved. Surgical rigid fixation was performed under intermaxillary fixation with surgical splints. Maxillary fixation was completed with two pre-bent titanium Le Fort I plate placed bilaterally at the piriform apertura with no zygomaticomaxillary buttress fixation. Prior to extubation, intermaxillary fixation and surgical splints were released. Intermaxillary elastics were used six to eight weeks following surgery in addition to a soft, no-chew diet. The patient received both preoperative and postoperative orthodontic treatment. Digital lateral cephalometric radiographs, which were taken one week before orthognatic surgery (T1), one week postoperatively (T2), and nine months postoperatively (T3), were used to analyze skeletal movement and stability of the maxilla. Lateral cephalometric measurements were performed digitally using a computer-assisted software program. Linear and angular measurements of sagittal and vertical maxillary positions was calculated. A horizontal reference plane (HR) +7° to the SN plane at the S point and a vertical reference plane (VR) 90° to the horizontal plane at the Sella point were used in the analyses. After completion of growth and development, the SN plane remains in the same position, giving us the opportunity to measure skeletal movement with these horizontal and vertical reference planes. The difference in the A point-HR distances between the pre and postoperative radiographs indicates the horizontal movement of the maxilla, whereas the difference in the A point-VR distances indicates the vertical movement of the maxilla. The major criteria for maxillary skeletal relapse was the change in the distance from the A point to the horizontal and vertical reference planes. Significant immediate postsurgical changes were found in early postoperative lateral cephalometric radiography (T2). In 9 month follow-up lateral cephalometric measurements (T3) all landmarks in the horizontal and vertical plane showed skeletal stability. The relapse amount in maxillary movement was less than 1 mm in both horizontal and vertical planes. According to the postoperative lateral cephalometric measurements, the two plate anterior fixation method in the one piece Le Fort I ostetomy showed satisfactory results in terms of skeletal stability.

Assessment of the upper respiratory tract in patients eligible for treatment with transverse maxillary expansion

Transverse maxillary hypoplasia may negatively affect respiration. Maxillary narrowing has to be treated early. An appliance for Rapid Maxillary Expansion (RME) is the most common method, and it aims to expand the skeletal base and maintain this width until a new bone has been formed to fill in the fissure. Aim. Comparison of the results of measurements of bone structures and of the upper airways on lateral teleroentgenograms of the head in patients with transverse maxillary hypoplasia and in patients with normal dimensions of the maxilla. Material and methods. The study was carried out in a group of 20 people with maxillary narrowing (10 girls and 10 boys) aged 7 to 10 years. The control group consisted of 20 lateral teleroentgenograms of patients (9 girls and 11 boys) of similar age treated for other malocclusions. The structures of the facial skeleton and the upper respiratory tract were assessed in teleroentgenograms after earlier determination of measurement points and planes according to selected parameters of the McNamara and Preston et al. methodology. The obtained results were analysed statistically using the Mann-Whitney's test. Results. Angular measurements showed statistically significantly smaller SNA and SNB angles in the study group compared to the control group. The analysis of linear measurements indicated a statistically significant larger dimension of the actual length of the midfacial segment (Co-A) and distance between the Sella point and the posterior nasal spine (PNS-S), and a smaller dimension of the posterior facial height (PFH) in the study group compared to the control group. The highest differences in upper respiratory tract measurements were noted in the Ba-ho-PNS angle, which was lower in the study group. The result was not statistically significant. Conclusions. No significant differences in cephalometric measurements of the upper airways were observed. There is a need to extend studies to include groups of patients with features of night apnoea and maxillary narrowing. &lt;b&gt;(Dargiewicz E, Szarmach IJ, Sawczuk M. Assessment of the upper respiratory tract in patients eligible for treatment with transverse maxillary expansion. Orthod Forum 2018; 14: 97-105)&lt;/b&gt;

Evaluation of size and morphology of sella turcica

Introduction: One of the most commonly used cranial landmarks for cephalometric tracing is sella point. Sella point is located in the centre of sella turcica with the turcica housing the pituitary gland in the crainal base. This gland lies within the pituitary fossa and consists of the anterior lobe, the intermediate lobe and the posterior lobe. Any abnormality or pathology in the gland could manifest from an altered shape of the sella turcica to a disturbance in the regulations of glandular hormones, prolactin, growth hormones, thyroid – stimulating hormone, follicular stimulating hormone, etc. Aims and Objective: The aim of the study was to determine difference in dimensions of sella turcica in different age groups and genders, that could assist in detection and evaluation of pathological conditions. Materials and Method: Lateral cephalometric radiographs of 100 individuals (50 males and 50 females) were evaluated retrospectively. The radiographs were divided into two groups according to the subject’s age: pre-pubertal (

Avaliação da simetria craniana através de imagens de TC cone beam

Objective: The aim of the present study was to compare the right and the left sides of symmetrical individuals´ skull through images generated by cone-beam computed tomography (cbct). Methods: The sample consisted of 35 scans from the 3d-i-cat (imaging sciences international inc., hatfield, usa) of 13 male and 22 female individuals, aged between 8 and 64, who showed acceptable facial symmetry. The images were entered into the invivodental 5.0 software (anatomage, san jose, usa) and positioned analogously to the patient´s head posture to get a lateral cephalometric radiography. Go-me, go-cd, s-cd, co-gn, and co-a linear distances (mm); mego.cd, fma, and gogn. sn angles (degrees), as well as five condyle-glenoid fossa linear distances (mm) were the bilateral variables analyzed. Results: Statistically significant difference between the right and the left sides was only verified when s-cd (mm) was assessed. Conclusion: therefore, there is no need to obtain bilateral values of these variables (except s-cd) to assess the skull of individuals with no evident asymmetries. In relation to s-cd variable, the difficulty to mark the sella point (s) in a 3-dimensional study created inexistent discrepancies between the right and the left condyles position.

Orthopedic effects of splint high-pull headgear—A cephalometric appraisal

Objective The purpose of this study was to investigate the orthopedic effect of maxillary splint high-pull head gear appliance on maxillary complex. Design Retrospective study. Settings Patients under treatment in the Department of Orthodontics, Azad University, during one year period from November 2003 to March 2004. Subjects Lateral cephalometric radiograph of 26 patients (11 boys and 15 girls, with a mean age of 11.3 years) treated with splint high-pull headgear appliance was compared with a similar control group of 26 individuals (11 boys and 15 girls with a mean age of 12.6 years). Main outcome measures The result of the present study showed that the treated group more closely approximated Class I cephalometric values after treatment, whereas the control group with a Class II skeletal pattern did not necessarily become “less Class II” due to growth. Results Point A was held efficiently in the treated group (S–A = 0.4 mm) whereas in the control group it had relocated downward and forward 2.00 mm along sella–point A (S–A) line. Also, the relocation of the point A in the horizontal ( X-axis) and vertical ( Y-axis) planes confirmed these findings. No rotational changes of palatal plane were recorded in the treated group. Mandibular skeletal changes were similar to the control group. Maxillary dentition was relocated more posteriorly. Conclusions It was concluded that the maxillary splint with high-pull headgear in the present study held the maxilla in position without any rotational changes of the palatal plane. Therefore, a normal skeletal relationship was achieved in the treated group through a combination of maxillary basal bone and dentoalveolar growth inhibition and a normal expression of mandibular growth.

A Protocol for Cranial Base Reference in Cephalometric Studies

Establishment of the cranial base references and the coordinate system is important for measurement of events occurring on the face. The literature suggests that the horizontal axis is obtained by tracing a line in clockwise direction at seven degrees from the Sella-Nasion line, and the vertical axis is perpendicular to this former axis passing through the Sella point. However, could this standardization better represent the angle between the Sella-Nasion line and Frankfort Horizontal Plane in a Brazilian population and be employed in cephalometric studies? Thus, the present study had two purposes: to identify the cranial base inclination in adult patients presenting with intermaxillary anteroposterior skeletal disharmony and to evaluate the reliability of a protocol to reproduce the cranial base reference. Lateral cephalograms of three different times were traced: T0) onset of orthodontic treatment and immediately before the orthognathic surgery, T1) six months after surgery, and T2) one year after surgery. The results displayed a mean cranial base inclination of 7.91 degrees. Variation of the intraindividual data allowed the conclusion that the protocol proposed by utilization of an individual template of the cranial base reference was effective for the exactness of measurements in cephalometric studies.

Sella-Nasion line revisited.

The anterior cranial base or the Sella-Nasion (SN) line is often used by orthodontists as a reference line for assessment of dentofacial deformities. Its most important value is its relative stability, practicality and the ease of location of both points Sella and Nasion. Reliability of the SN line as a suitable assessor for exact facial measurements has been discussed before. The intent of this study was to identify unusual SN rotations for subjects acquiring normal and abnormal skeletal profiles and hence correct values associated with SN line, both in vertical and horizontal planes. A random sample of 150 British white school children aged 9-12 years old was selected. Lateral head films of the children were traced and digitized. Point Nasion was joined to posterior nasal spine and also to point Sella, thus producing a Z angle when the posterior nasal spine is extended to anterior nasal spine. Means and standard deviations were calculated. The mean angle S-N-PNS was 38 degrees +/- 5 while the mean of angle N-PNS-ANS was 47 degrees +/- 3. Comparison of these angles for patients of the same age group with the mean Z angle can identify rotation of the palatal and Sella-Nasion planes. Hence corrections of angular measurements involving Sella point can be performed.

Spheno-Occipital Synchondrosis in Three-Month-Old Children with Clefts of the Lip and Palate: A Radiographic Study

The literature has been focused on differences in craniofacial form and dimension in cleft lip and palate patients. No attention has been given to possible alterations in the spheno-occipital synchondrosis although the synchondrosis is regarded as an important maturity and growth center. The purpose of the present investigation was to examine if the spheno-occipital synchondrosis in children born with major complete clefts differs on lateral radiographs from that of children born with minor incomplete clefts. Fifty-seven three-month-old children with complete clefts of the lip, alveolus and palate and 42 three-month-old children with minor incomplete clefts of the lip were included in the study. The results of the comparison showed that children with complete major clefts had a broader spheno-occipital synchondrosis compared to children with a minor incomplete cleft of the lip, and that the distance from the superior part of the synchondrosis to the sella point was shorter in children with complete clefts. These findings could be related to a defect or a delay in maturity in the early development of the cartilaginous cranial base in children with major clefts.

The effect of the amount of protrusion built into the Bionator on condylar growth and displacement: A clinical study

To evaluate the treatment effects of a variable degree of forward posturing of the mandible incorporated into the Bionator, a study was undertaken on 14 patients with Class II, Division 1 malocclusion, treated for 1 year with a Bionator, maintaining the mandible in an edge-to-edge incisal position (Be group). This group was compared with a matched group of patients treated with the Bionator in whom the mandible was maintained in a “functional maxipropulsion” (Bmax group). Both groups were subdivided further according to sex for selected parameters. Twenty-nine measurements on cephalometric x-ray films taken before and after 1 year of treatment were statistically analyzed. According to this study, “edge-to-edge” protrusion is superior to “functional maxipropulsion” in increasing ramal height. The difference in increase in corpus length after treatment (greater in boys than in girls) was sex related rather than dependent on appliance characteristics. When studying the effect of functional appliances, it is suggested that a patient group be subdivided by sex. After treatment a repositioning of the condyle was found in a more downward and possibly slightly forward direction relative to sella point (S) in both groups. A relocation of the condyle should be considered as another treatment effect of functional appliances. The more important lowering of the condyle found in the Bmax group may partly explain the significant increase in SNB, the 1.6-fold larger decrease in overbite, and the highly significant increase in anterior lower facial height in this group. The fact that the effects on ramal height and on condylar displacement were significantly more pronounced in the Be group and the Bmax group, respectively, was attributed to the different amount of protrusion built into the functional appliance. Comparative studies on the effects of functional appliances should standardize the degree of propulsion.

The Different Relationship of the Sella Point to Growth Sites of the Cranial Base in Fetal Life

Histological observations of the fetal cranial base in 17 human specimens showed that the sella point was identified closely with the dorsum sellae, and occupied an intermediate position in relation to the growth sites of the spheno-occipital synchondrosis. The cancellous structure of the sphenoid bone clearly demonstrated that the pituitary fossa, and hence the sella, moved upward and backward during growth.

The sella point and postnatal growth of the human cranial base

The sella point and postnatal growth of the human cranial base

A biologist looks at the sella point: By Prof. Louis J. Baume. Tr. European Orthodontic Society, 1957

A biologist looks at the sella point: By Prof. Louis J. Baume. Tr. European Orthodontic Society, 1957