Cephalometric X-rays Research Articles

Mandibular sagittal split osteotomy vs mandibular distraction osteogenesis in treatment of non-syndromic skeletal class II patients

Mandibular retrognathia is a common skeletal congenital dysgnathia. In many cases of skeletal class II patients require the surgical operation. Orthognatic surgery offers mandibular bilateral sagittal split osteotomy (BSSO) as the most common procedure to make the advancement of the mandible. However, the alternative, mandibular distraction osteogenesis (MDO), is prevalent nowadays and beneficial in particular cases. The purpose of this study is to show the effect of MDO and BSSO done on 20 patients at Specialist Children's Hospital in Olsztyn, Poland between 2011 and 2013, performed by the same surgeon – KD. Authors would like to present the details of treatment planning and management of these methods as well as the protocol of usage of the distraction device. The sample consisted of 74 lateral cephalometric X-rays. Criteria for cephalometric comparison were angular cephalometric variables: SNB and SN/GoGn (Steiner analysis). The criteria for inclusion into this study were as follows: males and females with skeletal class II pattern plus dentofacial and dental abnormalities like skeletal open bite. The mean age of the subjects was 17.9 years. Our comparison study showed that there was no statistically significant difference between results of BSSO postoperatively and MDO post-distraction. However, there is a need of long-term data on stability of both methods. Study shows that MDO may offer another option for treatment of skeletal class II malocclusions in growing patients and after growth spurt.

Controlling the vector of distraction osteogenesis in the management of obstructive sleep apnea.

Background:Obstructive sleep apnea (OSA) in individuals with craniofacial anomalies can compromise airway and is a serious life-threatening condition. In many cases, tracheostomy is carried out as the treatment of choice. Distraction osteogenesis of the mandible as a treatment modality for OSA is very useful and may spare the need for tracheostomy or allow decannulation, yet controlling the vector of distraction is still a major challenge. We present a method for controlling the vector of distraction.Materials and Methods:Eight patients with severe respiratory distress secondary to a micrognathic mandible were treated by mandibular distraction osteogenesis using either external or internal devices. Temporary anchorage devices (TADs) and orthodontic elastics were used to control the vector of distraction. Cephalometric X-rays, computed tomography, and polysomnographic sleep studies were used to analyze the results.Results:A mean distraction of 22 mm using the internal devices and a mean of 30 mm using the external devices were achieved. Increase in the pharyngeal airway and hyoid bone advancement was also observed. Anterior-posterior advancement of the mandible was noted with no clockwise rotation. Most importantly, clinical improvement in symptoms of OSA, respiratory distress, and feeding was noted.Conclusions:We describe a method for controlling the vector of distraction used as a treatment for OSA. In these cases, TADs were used as an anchorage unit to control the vector of distraction. Our results show excellent clinical and radiographical results. TADs are a simple and nonexpensive method to control the vector of distraction.

Variations of midfacial soft-tissue thickness between 6 and 18 years for the reconstruction of the profile: a help for facial reconstruction of children

Facial approximation techniques used in forensic anthropology are based on soft-tissue thickness databases. A potentially relevant application concerns the facial reconstruction of children in cases where only the skull can be recovered. Although several databases concerning facial soft tissues thicknesses already exist [1-3], no study has so far taken into consideration the Italian population. This study aims at providing data concerning facial thickness on the midline in a population of Italian children. Diagnostic cephalometric X-ray films were obtained from 222 healthy Caucasoid children (91 boys and 131 girls), aged between 6 and 18 years. After setting the Frankfurt plane horizontal, 15 measurements were taken at the mid-facial landmarks: supraglabella, glabella, nasion, nasale, subnasale, nasal tip, superior labial sulcus, labrale superius, stomion, labrale inferius, inferior labial sulcus, suprapogonion, pogonion, gnathion, menton. Mean and standard deviation of soft-tissues thickness at each point were calculated. A two-way analysis of variance (ANOVA) was performed to test the modifications of facial parameters with age and sex (p<0.01). The results demonstrated that there is an increase in tissue thickness as individuals grow; in most occasions, males showed thicker soft tissues than females of the same age, especially after the adolescent growth spurt. Facial thicknesses at subnasale, nasal tip, superior labial sulcus, labrale superius, labrale inferius, inferior labial sulcus, suprapogonion, pogonion and gnathion significantly modified with age, whereas the same parameters at subnasale, superior labial sulcus, labrale superius, labrale inferius, stomion and suprapogonion were significantly sexually dimorphic. In addition, a database for soft-tissue thicknesses in children aged between 6 and 18 years was created, which may be of interest in cases of facial approximation of Italian minors.

VERTICAL AND HORIZONTAL STABILITY FOLLOWING LE FORT I OSTEOTOMY WITHOUT BONE GRAFT

objectives: the study aimed to evaluate the vertical and horizontal stability following Le Fort I osteotomy without using any bone graft in patients with maxillary advancement up to 6 mm alone or combined with vertical repositioning. Patients and methods: patients referred for one piece Le Fort I osteotomy with or without other orthognathic procedures were included in this study. In all surgeries, the maxilla was fixed using titanium plates and no bone graft was used in any of the patients. Suspension wires were fixed to be used for IMF with elastics postoperatively. Lateral cephalometric X-rays were taken 1 week after the surgery (T1), and 1 year after the surgery (T2), these X-rays were used to evaluate the postoperative stability using the SNA angle, maxillary depth angle, palatal plane angle, and maxillary height angle to evaluate changes in the horizontal and vertical direction. results: The lateral cephalometric analysis for relapse in the anteroposterior direction showed that only 6 patients out of 18 (33.3%) encountered a relapse of more than 2° in SNA angle and 5 (27.7%) in the maxillary depth angle measurements. Yet in between those patients there was only one (5.5%) out of 18 patients had only maxillary advancement without vertical repositioning. The results of the maxillary height and palatal plane angles showed that all the changes of more than 2° in the vertical direction were in the elongation group (3 patients out of four) (75%) using the palatal plane angle while it was only 1 patient (25%) using the maxillary height angle evaluation. Conclusion: within the limitation of the present study (small sample number especially in the patients with vertical repositioning) ; the study suggests that the use of bone graft can be avoided in maxillary advancement movement up to 6 mm anterior repositioning even this was combined with superior repositioning. Moreover the study recommends the use of bone graft in cases of anterior maxillary advancement with inferior repositioning of the maxilla.

Changes of some functional speech disorders after surgical correction of skeletal anterior open bite

Skeletal anterior open bite (AOB) or apertognathism is characterized by the absence of contact of the anterior teeth and affects articulation parameters, chewing, biting and voice quality. The treatment of AOB consists of orthognatic surgical procedures. The aim of this study was to evaluate the effects of treatment on voice quality, articulation and nasality in speech with respect to skeletal changes. The study was prospective; 15 patients with AOB were evaluated before and after surgery. Lateral cephalometric x-ray parameters (facial angle, interincisal distance, Wits appraisal) were measured to determine skeletal changes. Before surgery, nine patients still had articulation disorders despite speech therapy during childhood. The voice quality parameters were determined by acoustic analysis of the vowel sound /a/ (fundamental frequency-F0, jitter, shimmer). Spectral analysis of vowels /a/, /e/, /i/, /o/, /u/ was carried out by determining the mean frequency of the first (F1) and second (F2) formants. Nasality in speech was expressed as the ratio between the nasal and the oral sound energies during speech samples. After surgery, normalizations of facial skeletal parameters were observed in all patients, but no statistically significant changes in articulation and voice quality parameters occurred despite subjective observations of easier articulation. Any deterioration in velopharyngeal insufficiency was absent in all of the patients. In conclusion, the surgical treatment of skeletal AOB does not lead to deterioration in voice, resonance and articulation qualities. Despite surgical correction of the unfavourable skeletal situation of the speech apparatus, the pre-existing articulation disorder cannot improve without professional intervention.

Evaluation and Comparison of Anatomical Landmark Detection Methods for Cephalometric X-Ray Images: A Grand Challenge.

Cephalometric analysis is an essential clinical and research tool in orthodontics for the orthodontic analysis and treatment planning. This paper presents the evaluation of the methods submitted to the Automatic Cephalometric X-Ray Landmark Detection Challenge, held at the IEEE International Symposium on Biomedical Imaging 2014 with an on-site competition. The challenge was set to explore and compare automatic landmark detection methods in application to cephalometric X-ray images. Methods were evaluated on a common database including cephalograms of 300 patients aged six to 60 years, collected from the Dental Department, Tri-Service General Hospital, Taiwan, and manually marked anatomical landmarks as the ground truth data, generated by two experienced medical doctors. Quantitative evaluation was performed to compare the results of a representative selection of current methods submitted to the challenge. Experimental results show that three methods are able to achieve detection rates greater than 80% using the 4 mm precision range, but only one method achieves a detection rate greater than 70% using the 2 mm precision range, which is the acceptable precision range in clinical practice. The study provides insights into the performance of different landmark detection approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques.

顔面非対称を伴う骨格性下顎前突症例の下顎骨形態の三次元計測による検討

With the exception of congenital anomalies, facial asymmetry is regarded as being caused by mandibular growth abnormalities in many cases. Conventionally, two-dimensional analysis using cephalometric X-rays is carried out to design the plan for orthognathic surgery. To improve the treatment outcome, however, it may be necessary to elucidate the factors responsible for asymmetry by performing three-dimensional analysis of the craniofacial morphology.The objective of the present study was to perform three-dimensional measurements of the mandible using three-dimensional computed tomography (3D-CT) in patients with facial asymmetry requiring orthognathic surgery, and to identify the morphological characteristics of the mandible by comparing the deviated and non-deviated sides.3D-CT images of 36 patients with facial asymmetry (≥ 4mm deviation of the mandibular midline) were analyzed using 3D planning software for orthognathic surgery. A total of 10 items were measured, including five angle measurements and five linear measurements with reference to the entire mandible, the mandibular body, or the mandibular ramus.The deviated and non-deviated sides were measured, and values were compared using the paired Student's t-test. Multi-regression analysis (step-wise selection) was also performed to evaluate the deviation of the mandibular midline and the items measured.In patients with facial asymmetry, a comparatively large mandibular ramus, mandibular body, and condylar process length were observed on the non-deviated side compared with the deviated side, with the mandibular ramus rotated anteromedially along the superior-inferior, left-right, and anterior-posterior axes. These differences between the deviated and non-deviated sides in the morphological characteristics of the mandible resulted in mandibular deviation and rotation. However, no left-right differences were observed in mandibular body height, mandibular body roll, or gonial angle. Our findings also suggested that deviation of the mandibular midline was significantly affected by mandibular ramus length, mandibular body length, and mandibular ramus pitch.

The Nasolabial Angle Among Patients with Total Cleft Lip and Palate.

Nasolabial angle is the angle that is measured between points columella, subnasale and labiale superius. The reference values vary from 90 to 120 degrees (the mean value is 109.8degrees). In some disorders, nasolabial angle might change. This influences the facial profile. One of such deformities are clefts. The nasolabial angle might be decreased in cleft patients due to deformation of the nose and upper lip that might be caused by the reconstructive surgical procedures performed. The aim of the study was to compare the nasolabial angle between the groups of patients with total clefts of the lip, alveolar bone and palate and healthy individuals. The cephalometric X-rays of 118 patients with clefts (73 boys and 45 girls) and 101 healthy individuals (32 boys and 69 girls) were taken into account to measure nasolabial angle and compared. In patients with cleft deformities, the nasolabial angle values were smaller than in healthy individuals. Among the patients with clefts, the ones with abilateral type of deformity are characterized by the highest mean values of nasolabial angle. The angle is smaller in groups of girls when compared to boys. Nasolabial angle in patients with total clefts of lip, alveolar bone and palate is statistically smaller than in healthy individuals. This might be aresult of either the deformation of the upper lip or (more probably) the nose. The orthodontic treatment should be individualized.

The nasomaxillary complex and the cranial base in artificial cranial deformation: relationships from a geometric morphometric study.

It is widely accepted that there is a relationship between the cranial base and the development of the nasomaxillary complex (NMC). The objective of the present study was to investigate the morphological relationship between these two anatomical units in skulls that have intentionally been subjected to one of two types of artificial deformity of the cranial vault [artificially deformed skulls (ADS)]. A geometric morphometry study was performed on lateral cephalometric X-rays of three groups of crania: 32 with anteroposterior (AP) deformity, 17 with circumferential (C) deformity, and 39 with no apparent deformity. The cranial base of the ADS showed marked deformity that produced a restriction of AP growth of the NMC, alterations of the roof of the orbit as a consequence of the rotation of anterior cranial fossa, and nasal protrusion. Pronounced morphological differences were found between the three groups: increased vertical development of the maxilla occurred in both ADS groups due to growth of the alveolar process, and rotation of the maxilla and displacement of the orbital rim was observed in the C group. This confirms that the posterior facial plane is regarded as an axial structure that serves as an interface between the middle cranial base and the NMC (Enlow, D.H. and Hans, M.G. (1996) Essential of Facial Growth. WB Saunders Co., Philadelphia, PA). It is important to take into account that these results have been obtained from an archaeological sample, with all the limitations that this implies such as being a small sample and with no absolute certainty regarding the use of the same type of deforming device within each group. Furthermore, this is a lateral two-dimensional study in which transverse development has not been analysed. Artificial modification of the shape of the vault has repercussions on the NMC that support the theory of an all-inclusive integration of the different cranial units in normal as well as in restricted development.

Diagnostic reference levels for panoramic and lateral cephalometric radiography of Korean children.

Pediatric patients are considered to be more radiosensitive than adults; thus, radiation dose evaluations based on radiologic examinations are particularly important in this population. However, no national diagnostic reference levels (DRLs) are available for pediatric patients in the Republic of Korea. Therefore, the aim of this study was to determine the usage of panoramic and cephalometric radiography under the National Health Insurance (NHI) scheme and to investigate the current DRLs for child panoramic and lateral cephalometric radiography using dose area product (DAP). DAP values were obtained for standard child exposure settings used routinely by dentists. Analysis was performed on data obtained from 28 panoramic and 20 cephalometric x-ray units for the DAP investigation. DRLs for child panoramic and cephalometric radiography were found to be 95.9 mGy cm and 121.3 mGy cm, respectively. These DRLs are higher than those recommended in the UK and Germany, which indicates that further effort is required to reduce pediatric doses in the Republic of Korea.

Anchor Plate Efficiency in Postoperative Orthodontic Treatment Following Orthognathic Surgery via Minimal Presurgical Orthodontic Treatment

Purpose:The efficiency of an anchor plate placed during orthognathic surgery via minimal presurgical orthodontic treatment was evaluated by analyzing the mandibular relapse rate and dental changes.Methods:The subjects included nine patients with Class III malocclusion who had bilateral sagittal split osteotomy at the Division of Oral and Maxillofacial Surgery, Department of Dentistry in Ajou University Hospital, after minimal presurgical orthodontic treatment. During orthognathic surgery, anchor plates were placed at both maxillary buttresses. The anchor plates were used to move maxillary teeth backward and for maximum anchorage of Class III elastics to minimize mandibular relapse during the postoperative orthodontic treatment. The lateral cephalometric X-ray was taken preoperatively (T0), postoperatively (T1), and one year after the surgery (T2). Seven measurements (distance from Pogonion to line Nasion-Nasion perpendicular [Pog-N Per.], angle of line B point-Nasion and Nasion-Sella [SNB], angle of line maxilla 1 root-maxilla 1 crown and Nasion-Sella [U1 to SN], distance from maxilla 1 crown to line A point-Nasion [U1 to NA], overbite, overjet, and interincisal angle) were taken. Measurements at T0 to T1 and T1 to T2 were compared and differences tested by standard statistical methods.Results:The mean skeletal change was posterior movement by 13.87±4.95 mm based on pogonion from T0 to T1, and anterior movement by 1.54±2.18 mm from T1 to T2, showing relapse of about 10.2%. There were significant changes from T0 to T1 for both Pog-N Per. and SNB (P <0.05). However, there were no statistically significant changes from T1 to T2 for both Pog-N Per. and SNB. U1 to NA that represents the anterior-posterior changes of maxillary incisor did not differ from T0 to T1, yet there was a significant change from T1 to T2 (P <0.05).Conclusion:This study found that the anchor plate minimizes mandibular relapse and moves the maxillary teeth backward during the postoperative orthodontic treatment. Thus, we conclude that the anchor plate is clinically very useful.

Estudio comparativo entre mestizas y caucásicos mediante el análisis cefalométrico de Ricketts

El objetivo del presente estudio fue comparar mediante radiografías cefalométricas, una muestra de adolescentes mestizas con las medidas estandarizadas de caucásicos de Ricketts, utilizado como patrón y determinar si hay diferencias significativas entre los valores encontrados. La población se basó en mujeres adolescentes del nivel secundario del colegio Rosa de Santa María del distrito de Breña, entre 11 a 16 años de edad. De la cual se escogió una muestra por conveniencia de 32 alumnas, con características del mestizaje peruano según patrones antropológicos. Se consideraron características extraorales e intraorales para la selección de la muestra, se utilizó el equipo de radiografía cefalométrico y una cámara fotográfica SRL para obtener un registro fotográfico de las características faciales. Los resultados fueron procesados usando el paquete estadístico SPSS v.17, expresando los resultados bajo medidas descriptivas y utilizando la prueba estadística Z para encontrar diferencias al 95% de confianza. Se concluyó que estas diferencias se hacen más evidentes en los siguientes valores: línea estética “E” 0,5 mm, ángulo ínter incisivo 124°, punto “A” a la línea N-Pg hasta en 4 mm, longitud anterior de la base craneal 56 mm, lo cual confirma la hipótesis que sí hay diferencias significativas entre la muestra de mestizas peruanas con las del grupo caucásico de Ricketts.

Cephalometric and three-dimensional assessment of the posterior airway space and imaging software reliability analysis before and after orthognathic surgery

PurposeThis study aimed to compare the reliability of three different imaging software programs for measuring the PAS and concurrently to investigate the morphological changes in oropharyngeal structures in mandibular prognathic patients before and after orthognathic surgery by using 2D and 3D analyzing technique. Material and methodsThe study consists of 11 randomly chosen patients (8 females and 3 males) who underwent maxillomandibular treatment for correction of Class III anteroposterior mandibular prognathism at the University Hospital in Zurich. A set of standardized LCR and CBCT-scans were obtained from each subject preoperatively (T0), 3 months after surgery (T1) and 3 months to 2 years postoperatively (T2). Morphological changes in the posterior airway space (PAS) were evaluated longitudinally by two different observers with three different imaging software programs (OsiriX® 64-bit, Switzerland; Mimics®, Belgium; BrainLab®, Germany) and manually by analyzing cephalometric X-rays. ResultsA significant increase in the upper airway dimensions before and after surgery occurred in all measured cases. All other cephalometric distances showed no statistically significant alterations. Measuring the volume of the PAS showed no significant changes in all cases. All three software programs showed similar outputs in both cephalometric analysis and 3D measuring technique. ConclusionA 3D design of the posterior airway seems to be far more reliable and precise phrasing of a statement of postoperative gradients than conventional radiography and is additionally higher compared to the corresponding manual method. In case of Class III mandibular prognathism treatment with bilateral split osteotomy of the mandible and simultaneous maxillary advancement, the negative effects of PAS volume decrease may be reduced and might prevent a developing OSAS.

Cephalometric investigation of craniomaxillofacial structures during the prenatal period: A cadaver study

We aimed to investigate the morphometric development of the cranial base and its related structures, and their growth rate changes from the ninth gestational week to full term in a large group of human fetuses. We selected 203 (109 male, 94 female) fetuses between 9 and 40 weeks of gestation and without any external anomalies. From each fetus, standard lateral and posteroanterior cephalometric images were taken using a dental digital panoramic and cephalometric x-ray machine. Fourteen linear and 9 angular parameters were measured. The cranial base angle showed a statistically significant increase between the groups from only the second to the third trimester periods. The sagittal translation of the maxilla increased during the prenatal period, whereas the mandibular sagittal relation grew at a steady rate. The vertical plane angles of the maxilla and the mandible did not show any significant changes. The maxillary length to mandibular length ratio remained stable. The cranial base angle increased, especially in the second through the third trimesters. The maxilla and the mandible demonstrated different growth patterns in the sagittal direction. The findings of this study could be a guide for interpreting the relationships among the craniofacial structures.

Short mandible – a possible risk factor for cleft palate with/without a cleft lip

To estimate the influence of a short mandible on the risk of developing a cleft palate with/without a cleft lip (CP). The retrospective sample consisted of 115 2-month-old Danish infants with CP, and 70 control infants with unilateral incomplete cleft lip (UICL). Cephalometric X-rays were obtained. Mandibular length (Lm ) was measured and corrected for body length (Lb ) to remove influence of varying body length in the sample. Logistic regression was applied to the corrected mandibular length (Lmc ) to calculate the risk of having a cleft palate. The mean mandibular length in the group with CP was about 4 mm shorter than in the control group. Odds ratio (OR) was calculated to be 0.58 (95% confidence interval 0.48-0.68), implying that an individual's risk of cleft palate with/without a cleft lip increases about 50% per mm decrease in mandibular length. A special facial type including a short mandible is a possible risk factor for cleft palate, and it was found that the risk of cleft palate increases 58% per mm decreases in mandibular length.

The effect of functional orthopedic treatment with removable appliance on young adults

Objective: To evaluate the treatment effects of a removable functional appliance (modified bionator) on young adults. Materials and Methods: A total of 12 skeletal CLII (class two) female patients, with average skeletal age 15.8-years old, used the modified bionator 16 h a day for 8 months. Lateral cephalometric X-rays were taken and analyzed before and after the treatment using paired t -test. Hand wrist X-rays were taken before the application of the appliance only. Results: After 8 months of treatment Angle CLI (class one) relationship was achieved; there was a significant reduction in the ANB (A-point Nasion B-point), SNA (Sella-Nasion-Apoint), face convexity, and overjet. SNB (Sella-Nasion-Bpoint) and face length significantly increased. Conclusion: The removable functional appliance - modified bionator - is an available option for correcting of borderline skeletal class II malocclusion in young adults or patients in late developmental stage.

Are bioresorbable polylactate devices comparable to titanium devices for stabilizing Le Fort I advancement?

The purpose of this study was to evaluate whether skeletal and dental outcomes following Le Fort I surgery differed when stabilization was performed with polylactate bioresorbable devices or titanium devices. Fifty-seven patients with preoperative records and at least 1 year postoperative records were identified and grouped according to the stabilization method. All cephalometric X-rays were traced and digitized by a single operator. Analysis of covariance was used to compare the postsurgical change between the two stabilization methods. Twenty-seven patients received bioresorbable devices (group R), while 30 received titanium devices (group M). There were no statistically significant differences between the two groups with respect to gender, race/ethnicity, age, or dental and skeletal movements during surgery. Subtle postsurgical differences were noted, but were not statistically significant. Stabilization of Le Fort I advancement with polylactate bioresorbable and titanium devices produced similar clinical outcomes at 1 year following surgery.

Reliability assessment and correlation analysis of evaluating orthodontic treatment outcome in Chinese patients

This study aimed to assess the reliability of experienced Chinese orthodontists in evaluating treatment outcome and to determine the correlations between three diagnostic information sources. Sixty-nine experienced Chinese orthodontic specialists each evaluated the outcome of orthodontic treatment of 108 Chinese patients. Three different information sources: study casts (SC), lateral cephalometric X-ray images (LX) and facial photographs (PH) were generated at the end of treatment for 108 patients selected randomly from six orthodontic treatment centers throughout China. Six different assessments of treatment outcome were made by each orthodontist using data from the three information sources separately and in combination. Each assessment included both ranking and grading for each patient. The rankings of each of the 69 judges for the 108 patients were correlated with the rankings of each of the other judges yielding 13 873 Spearman rs values, ranging from –0.08 to +0.85. Of these, 90% were greater than 0.4, showing moderate-to-high consistency among the 69 orthodontists. In the combined evaluations, study casts were the most significant predictive component (R2=0.86, P<0.000 1), while the inclusion of lateral cephalometric films and facial photographs also contributed to a more comprehensive assessment (R2=0.96, P<0.000 1). Grading scores for SC+LX and SC+PH were highly significantly correlated with those for SC+LX+PH (r(SC+LX)vs.(SC+LX+PH)=0.96, r(SC+PH)vs.(SC+LX+PH)=0.97), showing that either SC+LX or SC+PH is an excellent substitute for all three combined assessment.

Simultaneous Le-Fort I maxillary advancement as a template for mandibular repositioning using BSSO and a curvilinear distractor—a new technique for dentofacial deformities management

Background:Dentofacial-deformities are traditionally treated by maxillary and mandibular osteotomies conducted separately or simultaneously. Recently, distraction osteogenesis (DO) has become an irreplaceable part of the surgical armamentarium. Our aim is to describe a combined surgical technique of simultaneous maxillary Le-Fort I advancement as a skeletal template for mandibular surgical repositioning by means of bilateral-sagittalsplit-osteotomy (BSSO) with a curvilinear distractor based on a preliminary computerized presurgical prediction. Methods: Seven patients, all suffering from obstructive sleep apnea, who presented with a large skeletal open bite and severe mandibular retrusion were included. The presurgical procedure included orthodontic preparation and computerized planning. After performance of Le-Fort I maxillary advancement, a BSSO predistraction procedurewas initiated facilitating finalmandibular position as dictated by the surgical splint. Thereafter a curvilinear distractor was attached to the osteotomized mandible and the jaw was released allowing the distractor to be expanded freely until it could be fixed to the distal component. Then a simultaneous curvilinearDOwas conducted and the respective spiralmovement of the mandible was achieved. Lateral cephalometric X-rays, before and after surgery, were traced by plotting different skeletal landmark points and were then analyzed. Results: All patients tolerated the procedures well through completion. The average vertical change at point I for the maxillary and mandibular incisors and at points A and B was similar (3.14–4.21mm). However, the average horizontal changes at points I (of the mandibular incisors) and B were almost 5 times larger (14.28mm and 15mm, respectively). Conclusion: A simultaneous maxillary and mandibular surgical advancement protocol using maxillary Le-Fort I and mandibular BSSO with curvilinear DO is a useful and accurate technique for dentofacial-deformity management. This technique allows the surgeon to refine the reliability of the distraction and the final occlusion. Additionally this technique is preferable in terms of operation-time and expanses.

A New Geometric Intersection Point (Ms) to Determine the Spatial Position of Maxillary Sinus

Abstract Introduction: Cephalometeric landmark detection, is a knowledge intensive activity to identify on standardized lateral x-rays of the skull, to perform measurements needed for medical diagnosis, treatment planning and evaluation. For computation of analysis of steps and for determination of underlying structures, provided landmarks should be correctly localized. Due to the complexity of human anatomy sensed in a cephalometric x-ray, the landmarks are localized and constructed. Maxillary sinus has an important role to play in the formation of facial contours. Objective: Our aim is to check the validity of new geometric intersection point Ms, evaluating cephalometerically the spatial position of maxillary sinus and to find any correlation between the spatial position of maxillary sinus and sagittal dysplasias. Study design: A single-institution prospective analysis. Subjects and methods: A total of 20 lateral cephalograms were used, of both sexes, ranging in age from 18-25 years. These radiographs were from subjects, classified into class I and class II on the bases of ANB and Ao-Bo. Maxillary sinus was carefully analyzed and measured in linear dimensions of length and width and its spatial position was calculated by using a new geometric intersection point Ms, created by the intersection of the linear measurements, in relation to the anterior cranial base. The spatial position of maxillary sinus was calculated from the position of the intersection point Ms. The length and height of maxillary sinus was measured and compared in both the groups. Results: The mean of maxillary sinus length (MSL) and height (MSH) was 43.2 ± SD 3.2mm and 41.2 ± SD 3.8mm, respectively for classI (p value=0.595) and 44.2 ± SD 4.9mm and 43.0 ± SD 3.4mm, respectively for class II (p value=0.283). The intersection point Ms depicting centre of maxillary sinus from x-axis (Ms-Msx) was same for both the groups. Mean for Ms-Msy, was 37.3 ± SD 5.7 for class I and 37.8 ± SD 1.9 for class II (p value=0.796). No statistical significance was found among the results in both the groups. Conclusion: The length and height of maxillary sinus was calculated and the centre of maxillary sinus was calculated by the intersection of the two. This new point can contribute in calculating the spatial position of sinus and be an effective measure to study the convexity and concavity of the midface. In the present study, the length and height of the sinus did not alter with the increased or decreased ANB and Ao-Bo. There was no significant spatial position change of maxillary sinus with variation in ANB and Ao-Bo (sagittal). Regarding vertical parameters, Ms may have significant correlation with the various malocclusions.