The hierarchy of stability and predictability in orthognathic surgery with rigid fixation: an update and extension

A hierarchy of stability exists among the types of surgical movements that are possible with orthognathic surgery. This report updates the hierarchy, focusing on comparison of the stability of procedures when rigid fixation is used. Two procedures not previously placed in the hierarchy now are included: correction of asymmetry is stable with rigid fixation and repositioning of the chin also is very stable. During the first post-surgical year, surgical movements in patients treated for Class II/long face problems tend to be more stable than those treated for Class III problems. Clinically relevant changes (more than 2 mm) occur in a surprisingly large percentage of orthognathic surgery patients from one to five years post-treatment, after surgical healing is complete. During the first post-surgical year, patients treated for Class II/long face problems are more stable than those treated for Class III problems; from one to five years post-treatment, some patients in both groups experience skeletal change, but the Class III patients then are more stable than the Class II/long face patients. Fewer patients exhibit long-term changes in the dental occlusion than skeletal changes, because the dentition usually adapts to the skeletal change

Evidence and clinical decisions: Asking the right questions to obtain clinically useful answers

Orthodontists need to know the effectiveness, efficiency and predictability of treatment approaches and methods, which can be learned only by carefully studying and evaluating treatment outcomes. The best data for outcomes come from randomized clinical trials (RCTs), but retrospective data can provide satisfactory evidence if the subjects were a well-defined patient group, all the patients were accounted for, and the percentages of patients with various possible outcomes are presented along with measures of the central tendency and variation. Meta-analysis of multiple RCTs done in a similar way and systematic reviews of the literature can strengthen clinically-useful evidence, but reviews that are too broadly based are more likely to blur than clarify the information clinicians need. Reviews that are tightly focused on seeking the answer to specific clinical questions and evaluating the quality of the evidence available to answer the question are much more likely to provide clinically useful data

Short-term and long-term stability of surgically assisted rapid palatal expansion revisited

The purpose of this article is to present further longitudinal data for short-term and long-term stability, following up our previous article in the surgery literature with a larger sample and 2 years of stability data

Closer Look at the Stability of Surgically Assisted Rapid Palatal Expansion

To assess the amount of dental and skeletal expansion and stability following surgically assisted rapid maxillary expansion,

The Appalachian Model Teaching Consortium: Preparing Teachers for Rural Appalachia

The Appalachian Model Teacher Consortium is a partnership involving Radford University, Wytheville Community College, and the Grayson County (Virginia) School System. Its purpose is to prepare highly qualified teachers for rural southwest Virginia. The model was developed in response to the growing teacher shortage facing school districts in rural southwest Virginia. Poorer, more rural districts often have weaker tax bases that provide limited, and at times inadequate, financial support for their school districts. This lack of local resources often results in lower salaries and benefits when compared to many districts that compete for the shrinking pool of potential teachers. Additionally, rural communities are often geographically isolated areas and have fewer amenities that attract young teachers from outside the district. The Appalachian Model Teacher Consortium attempts to naturalize shortages by recruiting potential teachers from the local area, and providing incentives for them to stay and teach in their home community

Variables Affecting Measurements of Vertical Occlusal Force

Previous studies of occlusal force have provided conflicting results. The purpose of these studies was to determine whether the extent of vertical opening, contralateral occlusal support, or head posture influenced vertical occlusal forces during swallowing, simulated chewing, and maximum biting effort. Three samples of subjects with normal vertical facial proportions - one each of children, adolescents, and young adults - were evaluated to determine the effects of changes in small (2.5 vs. 6.0 mm) vertical separation of the first molars. A sample of young adults was used to evaluate changes in large (10-40 mm) vertical openings, and a sample of adolescents was used to investigate the effect of contralateral support and head posture. All between-group comparisons were evaluated using non-parametric statistics. For the small vertical openings, there was significantly more vertical occlusal force at 6.0 than 2.5 mm in children during swallowing and chewing but not during maximum biting effort. In adults, there was significantly more force during swallowing at 6.0 than at 2.5 mm separation, but no differences in chewing or maximum biting. Increasingly large vertical openings resulted in a progressive increase in maximum bite force to a maximum at about 20 mm, followed by a decrease and then a second increase to near-maximum force at about 40 mm for young adults. There were no significant differences in vertical force with or without contralateral support or between flexed, normal, and extended head postures at either of the small openings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68036/2/10.1177_00220345860650020901.pd

Extraction frequencies at a university orthodontic clinic in the 21st century: Demographic and diagnostic factors affecting the likelihood of extraction

The aims of this study were 1) to report contemporary orthodontic extraction frequencies at a university center and 2) to investigate what patient-related factors might influence the likelihood of extraction

The Luminosity Function of M3

We present a high precision, large sample luminosity function (LF) for the Galactic globular cluster M3. With a combination of ground based and Hubble Space Telescope data we cover the entire radial extent of the cluster. The observed LF is well fit by canonical standard stellar models from the red giant branch (RGB) tip to below the main sequence turnoff point. Specifically, neither the RGB LF-bump nor subgiant branch LF indicate any breakdown in the standard models. On the main sequence we find evidence for a flat initial mass function and for mass segregation due to the dynamical evolution of the cluster.Comment: 18 pages, 13 figures. ApJ, in pres

Stability After Mandibular Setback: Mandible-Only Versus 2-Jaw Surgery

The objective of this study was to evaluate whether changes in the technique for mandibular setback surgery since the introduction of RIF have improved postsurgical stability in Class III correction with setback alone and 2-jaw surgery

Long-term follow-up of Class II adults treated with orthodontic camouflage: A comparison with orthognathic surgery outcomes

Thirty-one adults who had been treated with orthodontics alone for Class II malocclusions were recalled at least 5 years posttreatment to evaluate cephalometric and occlusal stability and also their satisfaction with treatment outcomes. The data were compared with similar data for long-term outcomes in patients with more severe Class II problems who had surgical correction with mandibular advancement, maxillary impaction, or a combination of those. In the camouflage patients, small mean changes in skeletal landmark positions occurred in the long term, but the changes were generally much smaller than in the surgery patients. The percentages of patients with a long-term increase in overbite were almost identical in the orthodontic and surgery groups, but the surgery patients were nearly twice as likely to have a long-term increase in overjet. The patients’ perceptions of outcomes were highly positive in both the orthodontic and the surgical groups. The orthodontics-only (camouflage) patients reported fewer functional or temporomandibular joint problems than did the surgery patients and had similar reports of overall satisfaction with treatment, but patients who had their mandibles advanced were significantly more positive about their dentofacial images