The quality of treatment in the adult orthodontic patient as judged by orthodontists and measured by the Objective Grading System.

INTRODUCTION: The increase in adult orthodontic patients in the last 20 years makes it more likely that a clinician will have adult cases to present to the American Board of Orthodontics (ABO) for board certification. The applicability of the Objective Grading System (OGS) to adult dentitions, however, has not been reported. Therefore, the purpose of this study was to determine if well-treated adult cases, as designated by orthodontists, could pass the ABO clinical examination using the OGS. METHODS: Posttreatment casts of 35 adult patients from Temple University, Department of Orthodontics were ranked by 4 examiners based on visual examination of the quality of case finish using the Q-sort method. Data on each examiner's personal selection criteria to classify a well-treated case were gathered. Discrepancy index (DI) and OGS scores were measured, and the number of missing teeth was recorded. RESULTS: There was a moderate correlation between the rankings of the 4 examiners and their rankings to the OGS score. A 63% overall ABO pass rate was found. The pass rate for the well-treated cases and failure rate in the lower ranked group were both 100%. The DI scores of 97% of the cases were high enough to qualify as a board case, and 77% had 1 or more missing teeth after treatment. Examiners largely used the factors of the OGS in deciding if a case was well treated, with intercuspation being the most important factor. CONCLUSIONS: This study demonstrates that well-treated adult cases can pass the ABO clinical examination using the OGS. In addition, it illustrates that missing teeth automatically inflate the DI score and improve the OGS score.

Bone structure effect on root resorption.

OBJECTIVES: To explore if alveolar bone shape and density might promote external apical root resorption. SETTING AND SAMPLE POPULATION: Panoramic radiographs of 700 patients who had orthodontic treatment at Temple University were reviewed and 22 patients with radiographic evidence of root resorption on the lower incisors were selected for the study. Exclusion criteria included a history of systemic diseases, craniofacial abnormalities, tooth injury, endodontically treated teeth, and impacted teeth. METHODS: Pre-treatment (T1) and post-treatment (T2) cephalometric radiographs were converted into digital format and enhanced to reduce contrast variability and improve edge definition. Tooth length, root length, root area, alveolar area around the root including cortical area, area of medullary bone, and area of the symphysis were measured using an interactive software algorithm. A region of interest within the symphysis was also defined and trabecular space area and fractal dimension calculated as an estimate of bone density. RESULTS: Root area and tooth length were correlated negatively with changes in root area, tooth area, and root length. Larger teeth demonstrated a greater amount of root resorption. Dentoalveolar complex dimensions remained relatively unchanged during tooth movement. The amount of alveolar bone around the root, thickness of cortical bone, density of the trabecular network, and fractal dimension showed no significant correlation with the extent of the external apical root resorption. CONCLUSIONS: The results of this study suggest that the density and morphology of the dentoalveolar complex are not significant factors in the etiology of external apical root resorption.

Three-dimensional imaging of the craniofacial complex.

Orthodontic treatment requires the rearrangement of craniofacial complex elements in three planes of space, but oddly the diagnosis is done with two-dimensional images. Here we report on a three-dimensional (3D) imaging system that employs the stereoimaging method of structured light to capture the facial image. The images can be subsequently integrated with 3D cephalometric tracings derived from lateral and PA films (www.clinorthodres.com/cor-c-070). The accuracy of the reconstruction obtained with this inexpensive system is about 400 µ.

Relaxin affects the dentofacial sutural tissues.

This is a report of an exploratory study of how the hormone relaxin might modulate the remodeling of connective tissue within the craniofacial sutures and periodontal tissues. Relaxin is a hormone that was discovered to be produced by the pregnant female. It is responsible for the relaxing of the pubic symphysis; the birth canal is widened for parturition. It has also been shown to have effects on other areas of the body, including ligaments and regions containing collagen and fibroblastic activity. Twenty-one Swiss retired-breeder mice were used to: 1) immunohistochemically demonstrate the presence of relaxin within the sutures; 2) demonstrate its effects on the integrity of the suture-like tissues; and 3) assay its effects on protease activity. Relaxin in concentrations of 250 and 500 ng/ml was used in the treated samples and allowed to incubate in complete tissue culture for 24 h. The results indicate the presence of relaxin within the cranial suture. Histological observations revealed definite changes in the collagen fibril arrangement in the PDL - from being dense and highly organized with a perpendicular direction between tooth and bone to randomly organized and loose, lacking any direction between tooth and bone. An elevation in the protease activity was evident in the relaxin-treated samples. This naturally occurring hormone might be used as an adjunct to orthodontic therapy as it appears to have the capacity to alter the physical properties of the connective tissue within sutures, gingival tissue, and the PDL. Potential indications for use include instances of sutural and soft tissue adaptation of orthopedic expansion in non-growing patients by a reduction in the tension of the stretched soft tissue envelope following orthognathic surgery (particularly the expanded palatal mucosa), periodontal ligament remodeling during or after tooth movement promoting stability, rapid gingival tissue remodeling during space closure in extraction sites, and by a decrease in the amount of scar tissue formation following frenectomies.