THREE-DIMENSIONAL ASSESSMENT OF THE EFFECTS OF EXTRACTION ON THE SMILE IN CLASS II HIGH AND LOW MANDIBULAR PLANE ANGLE PATIENTS PDF Download
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Author: Neil E. Uffner Publisher: ISBN: Category : Languages : en Pages : 90
Book Description
The annals of orthodontics are filled with studies aimed to understand how extraction orthodontic treatment might change the face. Although many studies have addressed profile changes due to extraction treatment, fewer studies have focused on how extractions change a patients smile. With the advent of surface imaging systems such as 3dMD, it is now possible to visualize the smile, and any changes incurred during orthodontic treatment, in three dimensions. Subjects for this study were chosen from the pool of 11-18 year old patients treated at the Podray Orthodontic Clinic at the Temple University Kornberg School of Dentistry. Subjects were Cl II patients, and must have been treated with either extraction of any combination of premolars or treated without extraction. Subjects were divided into four experimental groups based on two characteristics- mandibular angle (those with angles greater than 28o versus those with angles less than 28o) and treatment (extraction versus non-extraction). The resulting groups were separated as follows: high-angle extraction patients (n=8), low-angle extraction patients (n=6), high-angle non-extraction patients (n=7), and low-angle non-extraction patients (n=15). For each subject initial and final 3dMD images were superimposed using 3dMD Vultus software. A color histogram was constructed to visualize changes during treatment. The cheeks, commissures, upper and lower lips, chin, and nose, were also landmarked, and the changes in these landmarks were calculated. Volume changes were also calculated between pre and post treatment 3D data. Results showed that the lower lip and right commissure changes between high-angle extraction and non-extraction groups were statistically significant. A qualitative analysis of the histograms further supported these findings. In general, a greater change in soft tissue landmarks and soft tissue volumes could be seen in high-angle patients than low-angle patients. Differences in the changes that result from treatment type (extraction vs. non-extraction) were seen in the high-angle group. In contrast, similar changes result from treatment type (extraction vs. non-extraction) in the low-angle groups. Furthermore, the lip changes seen in extraction patients upon smiling are very similar to those changes seen in the same patient in repose. Most interestingly, soft tissue differences of the face due to treatment, growth, or both, seem to disappear upon smiling, with the exception of the lips. Qualitative assessment of these changes in the smile might be a more appropriate method for identifying soft tissue changes than statistical analyses. Similar studies with larger sample sizes are a promising direction for future research.
Author: Neil E. Uffner Publisher: ISBN: Category : Languages : en Pages : 90
Book Description
The annals of orthodontics are filled with studies aimed to understand how extraction orthodontic treatment might change the face. Although many studies have addressed profile changes due to extraction treatment, fewer studies have focused on how extractions change a patients smile. With the advent of surface imaging systems such as 3dMD, it is now possible to visualize the smile, and any changes incurred during orthodontic treatment, in three dimensions. Subjects for this study were chosen from the pool of 11-18 year old patients treated at the Podray Orthodontic Clinic at the Temple University Kornberg School of Dentistry. Subjects were Cl II patients, and must have been treated with either extraction of any combination of premolars or treated without extraction. Subjects were divided into four experimental groups based on two characteristics- mandibular angle (those with angles greater than 28o versus those with angles less than 28o) and treatment (extraction versus non-extraction). The resulting groups were separated as follows: high-angle extraction patients (n=8), low-angle extraction patients (n=6), high-angle non-extraction patients (n=7), and low-angle non-extraction patients (n=15). For each subject initial and final 3dMD images were superimposed using 3dMD Vultus software. A color histogram was constructed to visualize changes during treatment. The cheeks, commissures, upper and lower lips, chin, and nose, were also landmarked, and the changes in these landmarks were calculated. Volume changes were also calculated between pre and post treatment 3D data. Results showed that the lower lip and right commissure changes between high-angle extraction and non-extraction groups were statistically significant. A qualitative analysis of the histograms further supported these findings. In general, a greater change in soft tissue landmarks and soft tissue volumes could be seen in high-angle patients than low-angle patients. Differences in the changes that result from treatment type (extraction vs. non-extraction) were seen in the high-angle group. In contrast, similar changes result from treatment type (extraction vs. non-extraction) in the low-angle groups. Furthermore, the lip changes seen in extraction patients upon smiling are very similar to those changes seen in the same patient in repose. Most interestingly, soft tissue differences of the face due to treatment, growth, or both, seem to disappear upon smiling, with the exception of the lips. Qualitative assessment of these changes in the smile might be a more appropriate method for identifying soft tissue changes than statistical analyses. Similar studies with larger sample sizes are a promising direction for future research.
Author: Jessica R Lynch (DMD) Publisher: ISBN: Category : Electronic dissertations Languages : en Pages :
Book Description
Introduction: The objective of this study was to compare pre-treatment and post-treatment cone-beam computed tomography images of patients to quantitatively evaluate the effect of orthodontically retracting maxillary incisors on the height and labiolingual thickness of labial and palatal alveolar bone and incisor apical root resorption. Methods: Maxillary central incisor apical root resorption, labial and palatal alveolar bone height, and labiolingual thickness were assessed on pre-treatment and post-treatment cone-beam computed tomography scans of 59 subjects (mean age, 13.00 years) with premolar extractions and 63 subjects (mean age, 13.40 years) who were treated with non-extraction therapy. Results: The mean incisor apical root resorption in the extraction group was 1.47± 0.70 mm, compared to 0.70± 0.81 mm in the non-extraction group (P
Author: Yasas Shri Nalaka Jayaratne Publisher: Open Dissertation Press ISBN: 9781361376638 Category : Languages : en Pages :
Book Description
This dissertation, "Three-dimensional Assessment of Facial Deformities and Their Surgical Outcomes" by Yasas Shri Nalaka, Jayaratne, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Data on the three?dimensional (3?D) morphology of normal faces and facial deformities as well as objective techniques for evaluating postoperative changes are currently unavailable. With the advent of stereophotography and cone?beam CT (CBCT), it is possible to acquire 3?D images of soft and hard tissues of the maxillofacial complex. A series of studies were conducted aimed at 1) establishing 3?D facial anthropometric norms for Hong Kong young adults, 2) determining 3?D facial anthropometric features in skeletal Class II and III deformities, 3) characterizing the oropharyngeal space in Class II and III skeletal deformities, 4) exploring clinical applications of 3?D colour maps, 5) establishing a non?invasive technique for estimating serial volume changes and 6) creating virtual craniofacial models by fusing 3?D photographs and CBCT images. Study 1: A stereophotographic system was used to capture 3?D images of 103 Hong Kong Chinese young adults with normal balanced faces. An anthropometric analysis protocol with linear, angular and proportional measurements was developed to establish a normative database and quantify dysmorphology. The Hong Kong Chinese norms were distinct from Caucasians, especially with regard to ocular and nasal measurements. Facial height and nasolabial measurements differed significantly between Hong Kong males and females. Study 2: Anthropometric analyses of 3?D facial images from 41 skeletal Class II and 43 Class III subjects were performed. The Class II subjects had increased lower facial height compared with Class III, who had longer total facial heights and narrower faces. While Class II deformity primarily resulted from mandibular deficiency with a normal maxilla, Class III presented as combined midfacial hypoplasia and mandibular hyperplasia. Study 3: Anthropometric characteristics of the oropharygeal space in skeletal Class II and III were evaluated using 62 CBCT scans. The retroglossal (RG) and retropalatal (RP) volumes and average cross sectional areas were significantly larger in Class III than Class II skeletal deformity. The RP compartment was larger but less uniform than the RG compartment in both Classes. Study 4: 3?D photographs or CBCT images acquired at two different time points were superimposed using a common unaffected area. 3?D colour maps were generated depicting distance differences between superimposed images in a graphical format. These maps were used as an objective tool for treatment planning and assessing outcomes after orthognathic surgery, bimaxillary distraction and facial trauma. Study 5: 3?D photogrammetry was employed for planning soft tissue expansion (STE) and transplantation of a vascularised scapular flap in hemifacial microsomia. This technique facilitated the identification of extent and degree of tissue deficiency, selection of the appropriate tissue expander, monitoring volumetric changes during STE and estimation of the free flap dimensions. Study 6: 3?D facial photographs and CBCT scans of 29 subjects were merged to create virtual craniofacial models with natural surface texture. Accuracy was assessed with 3?D
Author: Mei-Man Chong Publisher: Open Dissertation Press ISBN: 9781361303313 Category : Languages : en Pages :
Book Description
This dissertation, "Three-dimensional Comparison of the Upper Airway in Various Types of Dentofacial Deformities" by Mei-man, Chong, 臧薇敏, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Objectives 1. To define the normative airway of Chinese population using three-dimensional imaging and computer analysis 2. To evaluate the upper airway differences in patients with normal facial profile and those with skeletal class III deformity 3. To evaluate the differences in upper airway models among patients with different dentofacial deformities and describe the role of computational fluid dynamics (CFD) in the human upper airway Materials and Methods Part I: Three-Dimensional Analysis of the Normative Upper Airway in Chinese This was a cross-sectional observational study. Cone beam computerized tomography (CBCT) scans of one hundred patients were analyzed. Computer analysis of the different upper airway parameters were studied including airway length and volume, as well as airway dimensions at the axial level of the soft palate, hard palate, base of tongue, and epiglottis. The most constricted airway location was identified and correlation analysis with variables of interest was done. Part II: A Cone Beam Computerized Tomography Study of Airway in Skeletal Class I and Class III Cone-beam computed tomography (CBCT) records of 200 patients were used to evaluate the upper airway dimensions. This sample consisted of patients with normal facial profile (Class I) and those demonstrating skeletal class III deformities. Computer analysis of the upper airway parameters such as airway length, airway volume, airway anterior-posterior and cross-sectional area dimensions at the hard palate, soft palate, base of tongue and epiglottis were performed. The most constricted airway sites were identified. Part III: Computational fluid dynamics study of upper airway in different dentofacial deformities Cone-beam computed tomography records of 12 patients were used to evaluate the upper airway. This sample consisted of facial skeletal Class I, II and III subjects. The upper airway models were constructed to allow CFD simulations in the airway from the epiglottis to the hard palate. Cross-sectional area, pressure, velocity and resistance were measured based on the reconstructed meshed models. Results Part I: Three-Dimensional Analysis of the Normative Upper Airway in Chinese In 100 subjects (40 males, 60 females) aged 16-40 years with normal facial profile, we found that the most constricted site occurs at the level of the soft palate. This surface area of this site was found to be linearly correlated to the airway volume, suggesting a significant relationship between the most constricted area and the total airway volume. Gender differences were found in airway length, volume, and in the dimensions at the base of tongue and epiglottis region. The mean airway length was 54.12 mm + 6.19 for males and 49.25 mm + 4.86 for females; airway volume of 15.09 cm3 + 4.92 for males and 13.12 cm3 + 4.72 for females. Part II: A Cone Beam Computerized Tomography Study of Airway in Skeletal Class I and Class III The sample consisted of 100 Class I (41 males, 59 females) with a mean age of 25.4 years and 100 Class III (38 males, 62 females) with a mean age of 23.5 years. Gender differences were noted in the airway length, airway volume and dimensions at the base of tongue and epiglottis for both groups. Males showed longer airway length, larger airway volume, larger airway dimensions at the base of tongue and epiglottis co
Author: Krishnamurthy Bonanthaya Publisher: Springer Nature ISBN: 9811513465 Category : Face Languages : en Pages : 1965
Book Description
This is an open access book with CC BY 4.0 license. This comprehensive open access textbook provides a comprehensive coverage of principles and practice of oral and maxillofacial surgery. With a range of topics starting from routine dentoalveolar surgery to advanced and complex surgical procedures, this volume is a meaningful combination of text and illustrations including clinical photos, radiographs, and videos. It provides guidance on evidence-based practices in context to existing protocols, guidelines and recommendations to help readers deal with most clinical scenarios in their daily surgical work. This multidisciplinary textbook is meant for postgraduate trainees, young practicing oral surgeons and experienced clinicians, as well as those preparing for university and board certification exams. It also aids in decision-making, the implementation of treatment plans and the management of complications that may arise. This book is an initiative of Association of Oral and Maxillofacial Surgeons of India (AOMSI) to its commitment to academic medicine. As part of this commitment, this textbook is in open access to help ensure widest possible dissemination to readers across the world. ; Open access Unique presentation with contents divided into color-coded core competency gradations Covers all aspects of oral and maxillofacial surgery Supplemented with videos of all commonly carried out procedures as operative video Every chapter or topic concludes with "future perspective" and addresses cutting edge advances in each area Every topic has a pull out box that provides the most relevant systematic reviews/ key articles to every topic.
Author: Neil E. Uffner
Author: Neil E. Uffner
Author: John Dell Sauter
Author: David C. Freeman
Author: George Dee Bankhead
Author: Jessica R Lynch (DMD)
Author: Daniel J. Ganz
Author: Yasas Shri Nalaka Jayaratne
Author: Charles J. Bolender
Author: Mei-Man Chong
Author: Krishnamurthy Bonanthaya