Mark Hans - Academia.edu (original) (raw)

Papers by Mark Hans

Chest Journal, Sep 1, 2000

To determine the differences in craniofacial cephalometric variables between snoring and nonsnori... more To determine the differences in craniofacial cephalometric variables between snoring and nonsnoring children. Cross-sectional. Case Western Reserve University Dental School, Department of Orthodontics, and local Cleveland orthodontic private practices. Twenty-eight snoring and 28 nonsnoring children between the ages of 7 years and 14 years. Nonsnoring subjects were matched to snoring subjects by age, sex, and ethnicity (mean [+/- SD] age, 10+/-2 years; 82% white, 64% female). None. Snoring was assessed using a sleep behavior questionnaire administered to parents or guardians. The cephalometric radiographs of the study subjects were traced by a single investigator, and 1 angular measurement and 11 linear measurements of hard and soft tissues were recorded. The paired Student&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s t test was used to analyze the cephalometric data. Snoring children manifest a significantly narrower anterior-posterior dimension of the pharynx at the superior and most narrow widths. Snoring children also had a greater length from the hyoid to the mandibular plane. Snoring children appear to present craniofacial factors that differ from those of nonsnoring children.

American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics, 2015

The history of imaging and orthodontics is a story of technology informing biology. Advances in i... more The history of imaging and orthodontics is a story of technology informing biology. Advances in imaging changed our thinking as our understanding of craniofacial growth and the impact of orthodontic treatment deepened. This article traces the history of imaging in orthodontics from the invention of the cephalometer by B. Holly Broadbent in 1930 to the introduction of low-cost, low-radiation-dose cone-beam computed tomography imaging in 2015.

Specific craniofacial characteristics are reported to occur with obstructive sleep apnea syndrome... more Specific craniofacial characteristics are reported to occur with obstructive sleep apnea syndrome (OSAS). The purpose of this study was to determine whether craniofacial morphology differs between subjects with OSAS and heavy snorers, and to investigate how change in posture from upright to lying down affects the upper airway passage. Lateral head radiographs of ten persons diagnosed with OSAS(AHI &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 50) and ten snorers matched for age, height and weight without any history of daytime sleepiness, doctor-diagnosed OSAS, and no evidence of significant desaturation on overnight oximetry were obtained in both upright seated and awake supine positions. The posterior superior pharyngeal space in both the OSAS and snorers was reduced when changing from upright to supine posture (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05). Significant differences in cranial base alignment, ramus width relative to the middle-cranial fossa, position of the maxilla relative to the cranial base in the seated position (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.01) were noted between subjects with OSAS and subjects with snoring and less severe apnea. In addition, differences in the posterior superior pharyngeal space, tongue length, tongue to intermaxillary area ratio and hyoid position (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05) were demonstrated both in the upright and in the supine positions (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.05) in the OSAS compared to the snoring group. These results suggest that anatomic factors may predispose some snorers to develop OSAS. Measurements made from awake supine position lateral head radiographs revealed no additional differences between OSAS and snoring subjects when compared to measurements made on radiographs taken in the upright position.

The advent of cone beam computed tomography (CBCT) in orthodontics raises the question of how it ... more The advent of cone beam computed tomography (CBCT) in orthodontics raises the question of how it com-pares with existing diagnostic tools in providing useful quantitative measures. This study compared linear and angular measurements from craniometry (Cranio), plain film cephalometry (Ceph), three-dimensional cephalometry (3DCeph), and CBCT. Methods: Sixteen linear and fourteen angular measurements were tak-en using Cranio, Ceph, 3DCeph, and CBCT in 6”, 9”, and 12” field of views (FOV) from five dry skulls. Cranio values defined the “gold standard” for linear measurements, and Ceph values the angular. Paired t-tests and correlations were used for comparison. Results: For linear measurements, Ceph had the most sig-nificant differences, followed by 3DCeph and CBCT. All had high (r>0.75) correlations. Average discrep-ancies were 4.18 mm for Ceph, 1.32 mm for 3DCeph, and less than 1 mm for CBCT in all three FOVs. For angular measurements, CBCT(9) and CBCT(6) were not considered due to...

Seminars in Orthodontics, 2005

The Angle Orthodontist

To examine changes in hyoid to mandibular plane distance (H-MP) and tongue length (TL) between ch... more To examine changes in hyoid to mandibular plane distance (H-MP) and tongue length (TL) between children who had orthodontic treatment with and without rapid maxillary expansion (RME). Lateral and frontal cephalograms of 138 patients treated with RME and 148 controls treated without RME were used to measure pretreatment (T(1)) and posttreatment (T(2)) intermolar (IM) distance, lateronasal width (LNW), H-MP, and TL. Medical histories were used to collect demographic information, history of mouth breathing, difficulty breathing through the nose, and previous adenotonsillectomy. Groups were group-matched for age and gender. Descriptive statistics were calculated. Group means were compared using t-tests and chi-square statistics. Reliability was estimated using intraclass correlations and kappa statistics. Statistical significance was set at P < .05. At T(1), the RME group showed smaller LNW (24.83 ± 1.99 vs 26.18 ± 2.05) and IM (50.17 ± 2.3 vs 51.58 ± 2.83). The distance from H-MP wa...

Journal of Dentofacial Anomalies and Orthodontics, 2009

Journal of Dentofacial Anomalies and Orthodontics, 2010

The use of distraction osteogenesis to improve the airway volume of individuals affected by crani... more The use of distraction osteogenesis to improve the airway volume of individuals affected by craniofacial anomalies is common practice today. The methods of assessing the outcomes of such surgical procedures have changed over the last several years.

Seminars in Orthodontics, 2011

ABSTRACT During the last quarter of the 20th century, changes in clinical orthodontics were large... more ABSTRACT During the last quarter of the 20th century, changes in clinical orthodontics were largely driven by improvements in bracket design, attachment mechanisms, and arch wire materials. This focus on the mechanical aspects of treatment led to decreased clinical interest in the underlying biology of facial growth and, for a time, craniofacial practitioners often ignored the bio in biomechanics. There was even more disappointment after the completion of the Human Genome Project. Although this project promised exciting possibilities for biologically based manipulation of the growing face, the resulting data were interesting but in most cases not clinically useful. In 2001, the introduction of low-cost, low-radiation dose, high-resolution cone beam computed tomography (CBCT) in clinical orthodontics created the potential for new discoveries in craniofacial biology and facial growth. This technology provides researchers and clinicians with the tools needed to study 3-dimensional changes in craniofacial anatomy associated with the growth process and clinical care. In the 20th century, radiographic cephalometry was a pioneering advance that led to many fundamental insights into the behavior of the face and neurocranium during growth. CBCT imaging promises similar advances in the 21st century. However, to take advantage of this opportunity, clinicians will need to interpret 3D anatomic changes in the context of the underlying growth process. This paper presents a short history of imaging in orthodontics, reports on the current state of the art, and suggests 3 ways CBCT imaging may influence the future of the specialty.

The Angle orthodontist, 1994

Dentistry today, 2006

Three-dimensional imaging in dentistry offers many advantages with respect to diagnosis and treat... more Three-dimensional imaging in dentistry offers many advantages with respect to diagnosis and treatment planning. This article focuses on cone beam computerized tomography (CBCT), which combines conventional x-ray and computerized volumetric reconstruction to reproduce a 3- dimensional image. A search of the peer-reviewed dental literature was performed to determine clinical applications in dentistry. Applications include 3-dimensional imaging for implant placement, extraction

Revue d'Orthopédie Dento-Faciale, 2010

... Ceci confirme, tout comme les résul-tats des études mentionnées précé- demment, l'ef... more ... Ceci confirme, tout comme les résul-tats des études mentionnées précé- demment, l'effet de la DO mandibulaire sur le volume des voies aériennes OP. ... 21. Rodriguez JC, Dogliotti P. Mandibular distraction in glossoptosis-micrognathic association: Preliminary report. ...

Revue d'Orthopédie Dento-Faciale, 1994

... triques ainsi que sur celles de la littérature. Il se rapporte à l'utilisation évent... more ... triques ainsi que sur celles de la littérature. Il se rapporte à l'utilisation éventuelle d'appareils dentaires dans le traitement des formes modérées du SA OS et du ronflement lorsqu 'il est préjudi-ciable sur le plan de la vie sociale. ...

Sleep And Breathing, 2001

Craniofacial and anthropometric characteristics are identified risk factors for obstructive sleep... more Craniofacial and anthropometric characteristics are identified risk factors for obstructive sleep apnea syndrome (OSAS). Phase 1 of this study used cephalometric radiographs to record craniofacial measurements from 60 OSAS subjects with a respiratory disturbances index (RDI) of 20 or greater (group A) and 60 subjects with a history of loud snoring and an RDI less than 20 (group B). From this data set, a craniofacial risk index (CRI) was constructed using age, body mass index (BMI), and 14 cephalometric measures previously reported to be associated with OSAS. A separating boundary (CRIS) was established by using discriminant analysis to differentiate between the two groups. All measurements were determined by an investigator who was blinded to the subjects' RDI score. Phase 2 used a second sample of 19 group A and 47 group B subjects to test the ability of the CRI derived from the first sample to classify subjects in this second sample into the correct age group. The CRI was able to classify correctly 72.3% (34 of 47) of the group A subjects when all variables were used in the discriminant model. Using only four variables (age, BMI, hyoid mandibular plane distance, and tongue length) selected by the stepwise method, 72.3% (34 of 47) of the group B subjects and 78.7% of group A subjects were classified correctly. These results suggest that a stepwise CRI could be used to classify heterogeneous groups of individuals with increased RDI into subgroups with varying degrees of anatomic risk for disease. Such subgrouping by anatomic risk could be important in determining the pathophysiology of OSAS because it is likely that differences . 1520-9512,p;2001,05,02, 079,092,ftx,en;sbr00181x. in upper airway anatomy among individuals interacts with a variety of other factors to produce clinical illness.

Orthodontics and Craniofacial Research, 2004

Journal of Public Health Dentistry, 2004

Objectives: Theaim of this cross-sectional study was to assess the disparity in utilization of or... more Objectives: Theaim of this cross-sectional study was to assess the disparity in utilization of orthodontic services among high school students and to measure and characterize the extent of unmet treatment needs among untreated students at the time of examination. Methods: The sample consisted of 2,808 tenth grade students enrolled in different public and private high schools. All subjects completed a dental survey that included questions on demographic, dental health, and orthodontic services, and assessment of smile using the visual analog scale. A subsample of dental study casts that were available for 567 untreated subjects were scored using the Dental Aesthetic Index (DAI) to estimate unmet treatment need. Results: The orthodontic utilization rate was 37percent. The odds of being orthodontically treated were 8.7 times greater among those with dental visits within the past year than among those without, and three times greater among Caucasians than among other ethnic groups. The DAl indicated that the unmet treatment need was 29 percent, with ethnic minority groups having 2.6 greater odds of needing treatment than Caucasians. Conclusion: Minority groups and infrequent dental attenders may experience disparities in unmet orthodontic treatment need. [J Public Health Dent 2004;64 :

Journal of Oral and Maxillofacial Surgery, 1995

Journal of Oral and Maxillofacial Surgery, 1992

Journal of Craniofacial Surgery, 1998

The production of average &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;normat... more The production of average &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;normative&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; three-dimensional (3D) computed tomography surface images of the bony skull has only recently been explored. The authors wish to determine the effect of using sex- and ethnicity-specific adult average 3D skull images for comparisons with patient images at various stages of craniofacial surgical management (i.e., diagnosis, treatment planning, prosthetic design, image-guided operative procedures, and outcomes assessment). Craniofacial surgical reconstruction for abnormal patterns of development, cancer resection, or trauma are most likely to benefit from these comparisons. To morphometrically test the significance of separating normative 3D skull data by sex and ethnicity, the authors collected 52 3D, anatomical landmarks from 3D computed tomography scans of dry skulls of 20 Americans of European ethnicity and 20 Americans of primarily African (i.e., primarily African and some European) ethnicity. A Procrustes-based morphometric analysis of shape detects 1.2 times as much interethnic variance as intersex variance. The African American sample presents 4.2% more dolichocephaly, wider orbits, flatter nasal area, larger gnathic anatomy, and more procumbent dentition. Pooling the sexes across both groups, it is seen that men tend to have less bulbous crania, more protruding brows, noses, and masticatory muscle attachments, and relatively less protrusive palettes and anterior mandibles. Despite a small sample size (N = 40), the authors&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; results are statistically significant (P approximately 0.001 overall) for both of the main factors, sex and ethnicity, separately.