Using Networks To Understand Medical Data: The Case of Class III Malocclusions

A system of elements that interact or regulate each other can be represented by a mathematical object called a network. While network analysis has been successfully applied to high-throughput biological systems, less has been done regarding their application in more applied fields of medicine; here we show an application based on standard medical diagnostic data. We apply network analysis to Class III malocclusion, one of the most difficult to understand and treat orofacial anomaly. We hypothesize that different interactions of the skeletal components can contribute to pathological disequilibrium; in order to test this hypothesis, we apply network analysis to 532 Class III young female patients. The topology of the Class III malocclusion obtained by network analysis shows a strong co-occurrence of abnormal skeletal features. The pattern of these occurrences influences the vertical and horizontal balance of disharmony in skeletal form and position. Patients with more unbalanced orthodontic phenotypes show preponderance of the pathological skeletal nodes and minor relevance of adaptive dentoalveolar equilibrating nodes. Furthermore, by applying Power Graphs analysis we identify some functional modules among orthodontic nodes. These modules correspond to groups of tightly inter-related features and presumably constitute the key regulators of plasticity and the sites of unbalance of the growing dentofacial Class III system. The data of the present study show that, in their most basic abstraction level, the orofacial characteristics can be represented as graphs using nodes to represent orthodontic characteristics, and edges to represent their various types of interactions. The applications of this mathematical model could improve the interpretation of the quantitative, patient-specific information, and help to better targeting therapy. Last but not least, the methodology we have applied in analyzing orthodontic features can be applied easily to other fields of the medical science.</p

Relationship between cervical spine and skeletal class II in subjects with and without temporomandibular disorders

AIM. To assess changes of cranio-cervical structure and of hyoid bone position in skeletal Class II subjects with and without Temporomandibular disorders (TMD). MATERIAL AND METHODS. The cephalometric analysis of 59 subjects with skeletal Class II were evaluated and compared. The measurements considerated were: ANB as parameter of Class II and C0-C1 distance, C1-C2 distance, cranio-cervical angle and hyoid bone position for the cervical spine analysis. Patients were divided into two subgroups: patients with TMD (group A) and patients without TMD (group B). TMD were evaluated with the Diagnostic Criteria for TMD (DC/TMD). Descriptive statistics and Pearson and Spearman correlation analysis, with p-value <0,005, were performed. RESULTS. C0-C1 and C1-C2 distance values and hyoid bone position resulted within normal range in the majority of patients examined. Cranio-cervical angle was alterated in 33 patients. The reduction of this angle with the increase of the ANB value resulted statistically significant in the group A, according to Pearson correlation index. No other data was statistically significant. CONCLUSIONS. Significant relationship between skeletal Class II and cervical spine cannot be highlighted. The alteration of cranio-cervical angle seems to be mildly present, with backward counterclockwise rotation of the head upon the neck in the sample (group A and B). The presence of TMDs as key factor in changes of neck posture could explain the different result between the two groups about relationship between ANB and cranio-cervical angle. This result should be further analyzed in order to better understand if cervical spine changes could be related to mandibular postural ones in the cranio-cervical space or to temporomandibular joints retropositioning, more recognizable in Class II with TMD, which could determine functional changes in other structures of this unit; neck posture also could be the result of a compensatory/ antalgic mechanism in response to TM

The Reliability Of Facial Soft Tissue Landmarks With Photogrammetry

Introduction:With attention being given to the deleterious effects of radiation exposure from dental radiographs and inaccuracies in cephalometric soft tissue measurements, an alternative method of facial analysis with sufficiently reliable soft tissue landmarks should be developed. The goals of this study were threefold: (1) to define a new, low-cost method for capturing standardized frontal and sagittal facial images, (2) to determine on which photographic view that landmarks can be more reliably located, and (3) to determine which landmarks are appropriate for quantitative facial analysis. Materials and Methods:Simultaneous frontal and right sagittal facial images of 10 male and 10 female dental student subjects were captured using high-definition webcams as part of a low-cost set-up. Seventeen identical predefined facial soft tissue landmarks were located by 5 examiners on both types of images and were recorded as coordinate values. These coordinate values were used to calculate the best estimate of the true value for each landmark, mean deviation from this best estimate, and reliability in the X- and Y-axes using the Shrout-Fleiss intraclass correlation coefficient with corresponding 95% confidence intervals. Two examiners repeated the landmark location to evaluate intra-examiner reliability. Results:With a 95% confidence interval range of \u3e0.950, nose and mouth landmarks were among the most reliable landmarks on frontal and sagittal facial images. Converselyright soft tissue gonionwas one of the least reliable landmarks located in this study. In general, landmarks located by a single examiner showed greater reliability than when there were multiple examiners. Conclusions:This low-cost method yielded frontal and sagittal images sufficient for landmark identification. The magnitude of error varies between landmarks, is largest for poorly demarcated landmarks, and most had a non-circular envelope of error. Certain landmarks were more reliable on sagittal images and others were more reliable on frontal images. All landmarks had greater reliability and less mean deviation when located by a single examiner

Relationships Between Vocal Structures, the Airway, and Craniocervical Posture Investigated Using Magnetic Resonance Imaging

Peer reviewedPreprin

An overview of selected orthodontic treatment need indices

Orthodontics is a fast developing science as well as the field of medicine in general. The attempt of this book is to propose new possibilities and new ways of thinking about Orthodontics beside the ones presented in established and outstanding publications available elsewhere. Some of the presented chapters transmit basic information, other clinical experiences and further offer even a window to the future. In the hands of the reader this book could provide an useful tool for the exploration of the application of information, knowledge and belief to some orthodontic topics and questions

A qualitative analysis of perceptions of orthodontists in Concepción about removable orthodontic appliances

Indexación: Scopus.Objective: To determine the utilization, attitudes and perceptions about removable orthodontic appliances (ROA) among a sample of Chilean orthodontists. Materials and methods: Data collection was performed using semi-structured interviews with 10 orthodontists from diverse professional backgrounds. The analysis was performed using the “Grounded Theory” methodology, using Atlas.ti v.6.0.15. Results: We interviewed four men and six women (31 to 75 years old), with 7 to 53 years of experience as dentists, and 1 to 10 years of experience as orthodontists. All orthodontists have experience in private practice, five in public service, and one in a military institution. One-hun-dred and thirty-three codes were grouped into seven categories identified as follows: perception of orthodontists, control over treatment, ROA characteristics, ROA indications and contraindications, patients’ attitude to ROA, selection of treatment, and ROA utilization. Conclusion: In the selection of ROA, different factors are involved, including the characteristics of the dentist, of the patient, and the social context. The key factor in the utilization of ROA is the perception of control over treatment.http://www.joralres.com/index.php/JOR/article/view/334/31

Differential Scanning Calorimetry (dsc) Analyses Of Esthetic Nickel-Titanium Wires As-Received And After Clinical Use

Introduction: The demand for esthetic orthodontics has increased rapidly over the past few decades, and much progress has been made in the development of esthetic clear and translucent brackets for labial orthodontics. However, the majority of wires used with these clear brackets are still the traditional alloys. Recently, American Orthodontics (Sheboygan, WI) and Opal (Ultradent; South Jordan, UT) have released epoxy resin coated nickel-titanium archwires that give a tooth-colored appearance. American Orthodontics has released EverWhite and Opal has released Via Pearl. The goal of this study was to compare the thermal properties of these new archwires with their uncoated counterparts before and after clinical use via differential scanning calorimetry (DSC). Materials and Methods: Four types of nickel-titanium orthodontic archwires were evaluated in this study. The four types consisted of two epoxy coated wires and two comparable control wires of the same .016 x 0.022 inch dimension. The transformation temperatures and phase transformations of these wires were determined in the as-received condition and after 4 to 12 weeks in the oral cavity by differential scanning calorimetry. In addition, the amount of coating lost for each coated archwire after clinical use was determined using a scanned image of the wire and matlab software. Results: There were no statistically significant differences in thermal properties when comparing archwires before and after clinical use. However, significant differences were observed between the as-received uncoated and coated counterparts from both manufacturers. Both wire types lost a significant amount of esthetic coating after use, but the Opal Via Pearl wire maintained significantly more coating compared to the EverWhite type. Conclusions: The significant differences between as-received uncoated and coated wires from the same manufacturer indicate that these wires may perform differently in clinical situations contrary to the manufacturers\u27 claims. In addition, improvements to the coating processes or alternative wires are needed to provide a more esthetic archwire with limited coating loss

Spectrum, Winter 1992

Spectrum was a newsletter for students, faculty, staff and alumni of the Henry M. Goldman School of Dental Medicine, published from 1983-1992

Effects of Palatal Expansion on Speech Production

Introduction: Rapid palatal expanders (RPEs) are a commonly used orthodontic adjunct for the treatment of posterior crossbites. RPEs are cemented to bilateral posterior teeth across the palate and thus may interfere with proper tongue movement and linguopalatal contact. The purpose of this study was to identify what specific role RPEs have on speech sound production for the child and early adolescent orthodontic patient. Materials and Methods: RPEs were treatment planned for patients seeking orthodontics at Marquette University. Speech recordings were made using a phonetically balanced reading passage (“The Caterpillar”) at 3 time points: 1) before RPE placement; 2) immediately after cementation; and 3) 10-14 days post appliance delivery. Measures of vocal tract resonance (formant center frequencies) were obtained for vowels and measures of noise distribution (spectral moments) were obtained for consonants. Two-way repeated measures (ANOVA) was used along with post-hoc tests for statistical analysis. Results: For the vowel /i/, the first formant increased and the second formant decreased indicating a more inferior and posterior tongue position. For /e/, only the second formant decreased resulting in a more posterior tongue position. The formants did not return to baseline within the two-week study period. For the fricatives /s/, //, /t/, and /k/, a significant shift from high to low frequencies indicated distortion upon appliance placement. Of these, only /t/ fully returned to baseline during the study period. Conclusion: Numerous phonemes were distorted upon RPE placement which indicated altered speech sound production. For most phonemes, it takes longer than two weeks for speech to return to baseline, if at all. Clinically, the results of this study will help with pre-treatment and interdisciplinary counseling for orthodontic patients receiving palatal expanders

Dental workforce 2012

Summary: Access to reliable, comprehensive, timely and nationally consistent trend data is required to understand the current health workforce and for its future planning. There is particular interest in changes to the size and composition of the various health professions, and the potential impacts of these changes on health-care delivery. This report provides data on the Australian dental practitioner workforce in 2012. Size of the dental workforce In 2012, there were 19,462 dental practitioners registered in Australia. Three-quarters of these practitioners (14,687) were dentists. The number of employed dentists increased by 5.3%, from 12,599 in 2011 to 13,266 in 2012. There were 1,330 dentists working as specialists. Orthodontics was the most common specialty (518 dentists). In 2012, there were also 1,425 dental hygienists, 1,117 dental therapists, 1,100 dental prosthetists and 675 oral health therapists employed in their fields. Sex and age of the dental workforce Sex Dentistry is a male dominated profession; however, the proportion of female dentists increased to 36.5% in 2012 from 35.2% in 2011. Employed dental therapists, dental hygienists and oral health therapists, were predominantly women (96.9, 94.6% and 84.7%, respectively). Dental prosthetists were much more likely to be men. Women made up 14.7% of this workforce, an increase from 13.9% in 2011. Age The average age of dentists employed in 2012 was 43.4 (the same as in 2011) and 23.4% were aged 55 and over. Employed dental prosthetists, dental therapists, dental hygienists and oral health therapists were aged 49.1, 46.4, 37.4 and 31.0, on average, respectively. Working arrangements Dentists worked, on average, 37.0 hours per week in 2012, a slight decrease from 2011 (37.3 hours per week). In 2012, 31.7% dentists worked part time (less than 35 hours per week). The majority of employed dentists were working in private practice (79.7% of clinicians and 77.3% of all dentists). Most specialists worked in private practice (75.0%) and in Major cities (89.1%). Major cities had more dentists per capita than other areas in 2012 at 64.3 full-time equivalent (FTE) dentists per 100,000 population, and more than the Australian rate of 56.9 FTE dentists