Hispanic adolescent lip response to extraction and nonextraction orthodontic treatment.

INTRODUCTION: In orthodontics, treatment aims to improve the patient's occlusion and overall facial appearance. Extraction of 4 first premolars may improve the occlusion, but it may negatively impact a patient's facial harmony and create a "dished-in" appearance. Although many studies in orthodontic literature reviewed Caucasian patient soft-tissue change throughout extraction treatment, there is a void in the literature regarding Hispanic patients, who have different soft-tissue characteristics and may respond differently to extraction therapy. This study aimed to determine the influence of first premolar extractions on soft-tissue profile in Hispanic adolescents and whether there is a correlation between pretreatment lip strain and lip movement throughout treatment. METHODS: Lateral cephalograms and study models of 60 Hispanic patients were evaluated at pretreatment and posttreatment stages. Patients were divided into nonextraction and extraction groups and further subdivided on the basis of pretreatment lip strain. Cephalometric analyses were compared between the groups and subgroups, and a correlation analysis was conducted. RESULTS: There was a significant difference in lip position change between nonextraction and extraction groups. There was a significant increase in upper vermillion lip thickness in the extraction group. There was no significant difference in lip position change between the minimal and moderate-severe lip strain extraction groups. There was no significant correlation between pretreatment crowding or lip strain and lip position change. CONCLUSIONS: Hispanic patients' lips may retract less than Caucasian patients' lips in response to extraction treatment. Pretreatment lip strain and crowding may have less effect on retrusive lip movement than in Caucasian patients.

Maxillary arch perimeter prediction using Ramanujan's equation for the ellipse.

INTRODUCTION: The prediction of arch perimeter gained when expanding the arch or proclining the anterior incisors is particularly important in the decision of tooth extraction vs nonextraction therapy for orthodontic treatment. METHODS: Correlation of the measured perimeter of the maxillary dental arch and the calculated perimeter applying Ramanujan's equation for the perimeter of an ellipse was evaluated with 30 diagnostic casts of untreated maxillary dental arches. Both linear and circumferential measurements were made directly on the midbuccal surface of these maxillary arches. RESULTS: Ramanujan's equation had a high level of correlation when comparing the measured perimeter of the maxillary dental arch and the calculated perimeter with the 0.01 level (1.2% error) using a 2-tailed t test. The results were applied to Ramanujan's equation to predict maxillary arch perimeter gained by expansion or proclination of the incisors. CONCLUSIONS: The ellipse is an accurate geometric model of the maxillary arch form. The average amounts of maxillary arch perimeter gained were 0.73 mm per millimeter of intermolar expansion and 1.66 mm per millimeter of incisor protrusion.

Comparison of abnormalities in the sequence of growth stages in the skeletal maturity index vs cervical vertebral maturation.

OBJECTIVES: To evaluate the frequency of abnormal progression that could ultimately affect the reliability of the skeletal maturity index (SMI) and the cervical vertebral maturation (CVM) method that are most commonly used analyses for skeletal age assessment. MATERIALS AND METHODS: A retrospective design was used to compare 299 hand-wrist radiographs with 299 lateral skull radiographs regarding the number of abnormalities in the proposed sequence of maturation in the SMI and CVM methods. RESULTS: A significantly greater number of abnormalities occurred in the sequence of CVM progression compared with SMI (P < .001). Sex and age did not have an effect. CONCLUSIONS: Skeletal age assessment based on SMI is more accurate than CVM regarding the progressive sequence of stages.

Incidence and effects of genetic factors on canine impaction in an isolated Jewish population.

INTRODUCTION: The etiology of palatal canine impaction is multifactorial and includes a genetic contribution. The aim of this study was to find the incidence and effects of genetic factors on palatally impacted canines in a genetically isolated community of ultraorthodox Hassidic Jews of Ashkenazi decent. METHODS: For this study, we retrospectively evaluated 1000 charts of Hassidic Jewish patients. Their distribution was 58% female and 42% male, with a mean age of 14 years. RESULTS: From those patients, 49 (4.9%) were determined to have canine impaction. Of these 49, 69.4% had unilateral palatal impaction, 26.5% had bilateral palatal impaction, and 4.1% had unilateral labial impaction. The z-test of proportion showed that female patients have a greater percentage than males for unilateral palatal impaction (P <0.01) with left-side dominance (P <0.01). CONCLUSIONS: Our results imply that genetics plays a significant role in maxillary canine palatal impaction. A genetically isolated Hassidic Jewish community can be a useful group to study the effects of genetic factors on various dental anomalies, including palatally displaced canines.

Tgif1 represses apolipoprotein gene expression in liver.

TG-interacting factor (Tgif1) represses gene expression by interaction with general corepressors, and can be recruited to target genes by transforming growth factor beta (TGFß) activated Smads, or by the retinoid X receptor (RXR). Here we show that Tgif1 interacts with the LXRα nuclear receptor and can repress transcription from a synthetic reporter activated by LXRα. In cultured cells reducing endogenous Tgif1 levels resulted in increased expression of LXRα target genes. To test the in vivo role of Tgif1, we analyzed LXRα-dependent gene expression in mice lacking Tgif1. In the livers of Tgif1 null mice, we observed significant derepression of the apolipoprotein genes, Apoa4 and Apoc2, suggesting that Tgif1 is an important in vivo regulator of apolipoprotein gene expression. In contrast, we observed relatively minimal effects on expression of other LXR target genes. This work suggests that Tgif1 can regulate nuclear receptor complexes, in addition to those containing retinoic acid receptors, but also indicates that there is some specificity to which NR target genes are repressed by Tgif1.

The Runx3 distal transcript encodes an additional transcriptional activation domain.

The runt family transcriptional regulator, Runx3, is upregulated during the differentiation of CD8 single-positive thymocytes and is expressed in peripheral CD8(+) T cells. Mice carrying targeted deletions in Runx3 have severe defects in the development and activation of CD8(+) T cells, resulting in decreased CD8(+) T-cell numbers, aberrant coexpression of CD4, and failure to expand CD8(+) effector cells after activation in vivo or in vitro. Expression of each of the three vertebrate runt family members, including Runx3, is controlled by two promoters that generate proteins with alternative N-terminal sequences. The longer N-terminal region of Runx3, expressed from the distal promoter, is highly conserved among family members and across species. We show that transcripts from the distal Runx3 promoter are selectively expressed in mature CD8(+) T cells and are upregulated upon activation. We show that the N-terminal region encoded by these transcripts carries an independent transcriptional activation domain. This domain can activate transcription in isolation, and contributes to the increased transcriptional activity observed with this isoform as compared to those expressed from the ancestral, proximal promoter. Together, these data suggest an important role for the additional N-terminal Runx3 activation domain in CD8(+) T-cell function.

Lateral comparisons using Fishman's skeletal maturation assessment.

OBJECTIVE: To assess lateral differences between ossification events and stages of bone development in the hands and wrists utilizing Fishman's skeletal maturation indicators (SMIs). MATERIALS AND METHODS: The skeletal ages of 125 subjects, aged 8 to 20 years, were determined with left and right hand-wrist radiographs using Fishman's SMI assessment. Each subject was also given the Edinburgh Handedness Questionnaire to assess handedness. The skeletal ages of both hand-wrist radiographs were analyzed against each other, handedness, chronologic age, and gender. RESULTS: There were no significant differences overall in right and left SMI scores (P  =  .70); 79% of all patients showed no difference in right and left SMI scores, regardless of handedness, gender, or age. However, when patients were categorized based on clinical levels of SMI score for the right hand-wrist, there was a significant difference (P  =  .01) between the SMI 1-3 group and the SMI 11 group. Subjects in the SMI 1-3 group were more likely to show a left > right SMI score, while subjects in the SMI 11 group were likely to show a right > left SMI score. CONCLUSION: Although no significant overall lateral differences in SMI scores were noted, it may be advisable to obtain a left hand-wrist radiograph and/or additional diagnostic information to estimate completion of growth in young surgical patients.