Adaptive response of the human dental alveolar process: correction of a Class I protrusive and mutilated dentition, with 32-year follow-up.

A healthy young woman with a severe Class I dental malocclusion and extreme maxillary arch protrusion was treated with conventional edgewise-arch fixed appliance therapy. Four first premolars were removed, and the mandibular second and third molars were moved into positions normally occupied by the mandibular first and second molars. Diagnostic records at ages 17 years 5 months, 22 years 11 months, and 54 years 8 months are presented. (These pretreatment and posttreatment records were presented to the American Board of Orthodontics in 1976 in partial fulfillment of its requirements for the certification process.)

A model for digital archiving of radiographs into a searchable database.

Digital images are routinely used in orthodontic practices today. Many systems and formats are available for producing, storing, retrieving, viewing, and sharing these images. The digital imaging and communication in medicine (DICOM) standard is designed to ensure that these systems and formats are compatible, so that an image produced in a small private practice today can be viewed next year in a large hospital. The purpose of this article is to describe a method for laser scanning and digitization of analog (film) radiographs that meets DICOM standards and allows for web-based archiving, searching, and retrieval.

Asymmetric mandibular prognathism: a 30-year retrospective case report.

A healthy white man with marked facial and dental asymmetry, a consequence of unilateral mandibular condylar hyperplasia, was treated with conventional fixed edgewise appliance therapy combined with orthognathic surgery (bilateral sagittal split osteotomy of the mandibular ramus). Pretreatment, posttreatment, and long-term follow up records for the patient at ages 26 years 11 months, 28 years 6 months, and 58 years 7 months are presented. Thirty years after treatment, the results remain stable. The pretreatment and posttreatment records were presented to the American Board of Orthodontics in 1976 in partial fulfillment of the requirements for board certification.

Retrospective analysis of long-term stable and unstable orthodontic treatment outcomes.

INTRODUCTION: The purpose of this study was to compare groups of patients with the most stable and the most unstable treatment results as rated by the peer assessment rating (PAR) index to identify factors associated with stability. All factors with significant crude odds ratios were investigated to create a multiple logistic regression model that could be used to predict stability. METHODS: The sample of 86 patients (30 male, 56 female), from the post-retention archives at the University of Washington, was not restricted to specific malocclusion types or treatment modalities with the exception of Angle Class III patients, who were excluded. The sample was divided into 2 groups, stable (n = 45) and unstable (n = 41), based on post-retention unweighted PAR scores and PAR score changes between posttreatment and post-retention. Model and radiographic measurements were made before treatment, after treatment, and after retention (average 14.4 years). RESULTS: The results showed that male sex and a sustained period of growth were related, and both were associated with increased instability. The initial severity of malocclusion, as graded by the PAR index and the irregularity index, was negatively correlated with post-retention stability-ie, patients with more severe index scores before treatment tended to be less stable. Differences in American Board of Orthodontics scores after treatment were diminished after retention. CONCLUSIONS: The factors associated with predicting stability were pretreatment arch length, pretreatment PAR score, molar classification, and sex.

Temporomandibular joint in miniature pigs: anatomy, cell replication, and relation to loading.

The mechanical environment is a regulator of growth and adaptation of the musculoskeletal system, including joints. Although pigs (Sus scrofa) are used frequently as models for temporomandibular joint (TMJ) dysfunction, no systematic description of microanatomy exists for this species. We injected the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) into 10- to 11-month-old miniature pigs that were undergoing measurements of TMJ bone strain. Ten hr later, the animals were sacrificed and their heads were perfused. Histological sections were used to map the distribution of replicating cells. Additional observations were made on gross dissections of jaw joints obtained from an abattoir. The pig TMJ is better supported than that of humans laterally and medially, but more vulnerable posteriorly. The posterior attachment area of the intra-articular disc is fibro-fatty rather than vascular, as in humans. Cartilage lines the articular eminence as well as the condylar surface. At the posterosuperior region of the condyle, the cartilage ends abruptly and is replaced by an invaginating, actively replicating periosteum. Almost all of the BrdU-labeled cells resided in the prechondroblastic zones. The condyle had more replicating cells than did the eminence (P < 0.02), but lateral and medial locations did not differ in either element. In sagittal sections, the condyle had more replicating cells posteriorly (P < 0.001), but no A-P differences were seen in the eminence. Comparisons of these data with data on bone strain indicate that increased loading is negatively associated with cell replication.