Effects of different orthodontic retention protocols on the periodontal health of mandibular incisors.

OBJECTIVES: To test the following two hypotheses: 1) different types of retainers result in distinct levels of biomarkers in gingival crevicular fluid (GCF) and 2) the retainer bonded to all mandibular anterior teeth induces more detrimental outcomes to the periodontium. SETTING AND SAMPLE POPULATION: The Department of Orthodontics at the University of Florida. The population consisted of individuals in the retention phase of orthodontic treatment. MATERIAL AND METHODS: This was a cross-sectional study that enrolled 36 individuals. Subjects in group 1 had retainers bonded to the mandibular canines only. Group 2 consisted of individuals having retainers bonded to all mandibular anterior teeth. Group 3 included patients using mandibular removable retainers. After clinical examination, GCF was collected from the mandibular incisor and biomarker levels were compared between the groups. RESULTS: Plaque accumulation and gingivitis differed significantly among groups, with the highest median values in group 2 subjects. Pairwise comparison of the groups with respect to gingivitis showed significant differences between groups 1 and 2. Significant differences among groups were detected for RANKL, OPG, OPN, M-CSF, MMP-3, and MMP-9. The ratio RANKL/OPG was significantly higher in group 2 subjects, with pairwise comparisons indicating that groups 1 and 2 differed from group 3. CONCLUSION: An association was found between orthodontic retention groups and GCF biomarker levels, which should be further explored in longitudinal studies. The presence of retainers bonded to all anterior teeth seems to increase plaque accumulation and gingivitis.

Is BMI greater than 60 kg/m(2) a predictor of higher morbidity after laparoscopic Roux-en-Y gastric bypass?

BACKGROUND: It has been hypothesized that patients who are super-super morbidly obese, defined as having a body mass index (BMI) of 60 kg/m(2) or higher, have an increased rate of postoperative complications. As surgical techniques and operator experience with Roux-en-Y gastric bypass improved with time, the selection criteria have expanded to include the super-super morbidly obese. We hypothesize that a higher BMI does not predict a higher postoperative complication rate. METHODS: The prospectively collected database for our Accredited Bariatric Program was queried for all laparoscopic Roux-en-Y gastric bypass procedures performed between January 2004 and July 2006. All cases were performed by a single surgeon at a tertiary-care center. Average postoperative follow-up time was 1 year. Patients were stratified into two groups: BMI < 60 kg/m(2) and BMI >or= 60 kg/m(2). The number of postoperative complications was compared between the two groups using a chi-square method with Yates correction. RESULTS: One hundred and sixty-nine patients with adequate follow-up data were identified during the study period. Of these, 148 patients had BMI < 60 kg/m(2) (group 1) and 21 had BMI >or= 60 kg/m(2) (group 2). There were 28 (19%) total complications in group 1, and 4 (19%) total complications in group 2. There was no statistical difference between the two groups (p = 0.98). Stricture rate was 10% in group 1 and 5% in group 2. CONCLUSION: Patients with BMI >or= 60 kg/m(2) do not have a higher postoperative morbidity compared with other patients undergoing laparoscopic Roux-en-Y gastric bypass. The stricture rate is less in patients with BMI >or= 60 kg/m(2) compared with other patients. Longer follow-up is required to detect complications that occur after 1 year. Our study shows that laparoscopic Roux-en-Y gastric bypass can be safely performed on the super-supermorbidly obese.

Osteoclast polarization and orthodontic tooth movement.

INTRODUCTION: Osteoclasts polarize when they contact activation signals that are associated with bone. Polarization is required for bone resorption and involves highly specialized mechanisms that represent attractive targets for the development of osteoclast-specific therapeutic agents. One potential use of such agents is to block tooth movement in spatially discrete locations to provide orthodontic anchorage. MATERIALS AND METHODS: Our group's research was directed toward the development of agents that inhibited the polarization of osteoclasts, and efforts were underway to develop means to experimentally modulate orthodontic tooth movement. We performed 'proof-in-principle' experiments demonstrating pharmacological blockades of orthodontic tooth movement using integrin and matrix metalloproteinase inhibitors in a rat model. RESULTS: We identified novel mechanisms underlying osteoclast bone resorption. Interactions between vacuolar H(+)-ATPase and the microfilament cytoskeleton that were unique to osteoclasts were described and characterized. Our group is now seeking to make use of this new knowledge, coupled with an emerging technique, supercomputer-based molecular modeling for the rational development of novel, osteoclast-specific therapeutic agents. CONCLUSION: Fresh insight into the molecular details of osteoclastic bone resorption provides new opportunities for identifying agents to selectively modulate osteoclast activity. Such agents may contribute to evolution of the practice of orthodontics.

Brain lateralization probed by water diffusion at the atomic to micrometric scale.

Combined neutron scattering and diffusion nuclear magnetic resonance experiments have been used to reveal significant interregional asymmetries (lateralization) in bovine brain hemispheres in terms of myelin arrangement and water dynamics at micron to atomic scales. Thicker myelin sheaths were found in the left hemisphere using neutron diffraction. 4.7 T dMRI and quasi-elastic neutron experiments highlighted significant differences in the properties of water dynamics in the two hemispheres. The results were interpreted in terms of hemisphere-dependent cellular composition (number of neurons, cell distribution, etc.) as well as specificity of neurological functions (such as preferential networking).

Anomalous water dynamics in brain: a combined diffusion magnetic resonance imaging and neutron scattering investigation.

Water diffusion is an optimal tool for investigating the architecture of brain tissue on which modern medical diagnostic imaging techniques rely. However, intrinsic tissue heterogeneity causes systematic deviations from pure free-water diffusion behaviour. To date, numerous theoretical and empirical approaches have been proposed to explain the non-Gaussian profile of this process. The aim of this work is to shed light on the physics piloting water diffusion in brain tissue at the micrometre-to-atomic scale. Combined diffusion magnetic resonance imaging and first pioneering neutron scattering experiments on bovine brain tissue have been performed in order to probe diffusion distances up to macromolecular separation. The coexistence of free-like and confined water populations in brain tissue extracted from a bovine right hemisphere has been revealed at the micrometre and atomic scale. The results are relevant for improving the modelling of the physics driving intra- and extracellular water diffusion in brain, with evident benefit for the diffusion magnetic resonance imaging technique, nowadays widely used to diagnose, at the micrometre scale, brain diseases such as ischemia and tumours.

Temporomandibular joint reconstruction after failed teflon-proplast implant: case report and literature review.

Multiple reports document that a foreign-body giant cell reaction forms around Proplast-Teflon temporomandibular joint (TMJ) implants. This results in destruction of surrounding bone and instability of the implants. This case presents a patient whose Proplast-Teflon TMJ implants became displaced into her middle cranial fossa. The staged reconstruction of this patient is described, including removal of the TMJ implants, reconstruction of the defect, concomitant orthodontic treatment and final reconstruction with TMJ Concepts. This process involved a multidisciplinary approach between several medical and dental specialties. At her 3-year follow up, the patient had a stable postoperative result.

Nuclear factor kappaB p65 phosphorylation in orthodontic tooth movement.

Osteoclasts play a vital role in orthodontic tooth movement. Transactivation of nuclear factor kappaB (NFkappaB) by phosphorylation of the p65 component of NFkappaB at amino acid 536 (p65*(536)) plays a role in osteoclast differentiation stimulated by receptor activator of nuclear factor kappaB-ligand (RANK-L). We hypothesized that this transactivation pathway might be involved in the responses of alveolar bone cells during orthodontic tooth movement. We detected sharp increases in the levels of p65*(536) 3 and 12 hrs after the application of orthodontic stimuli in rats. In cell culture, osteoclast-like cells displayed no changes in p65*(536) in response to RANK-L, but levels rapidly increased after the cells were mechanically scraped. We conclude that p65*(536) is produced rapidly in response to orthodontic stimuli and mechanical insults, and may be important in bone remodeling associated with orthodontic tooth movement.

Effects of matrix metalloproteinase inhibitors on bone resorption and orthodontic tooth movement.

Matrix metalloproteinases are involved in the regulation of bone remodeling. The hypothesis that matrix metalloproteinase inhibitors may be useful for experimentally limiting orthodontic tooth movement, a process involving perturbations of normal bone remodeling, was tested. General matrix metalloproteinase inhibitors limited the resorption of bone slices by mouse marrow cultures stimulated by calcitriol, parathyroid hormone, and basic-fibroblast growth factor. Pre-coating dentin slices with short arginine-glycine aspartic acid (RGD) peptides, but not arginine-glycine-glutamic acid (RGE) controls, restored bone resorption in the presence of matrix metalloproteinase inhibitors. Orthodontic tooth movement was inhibited by local delivery of Ilomastat, a general matrix metalloproteinase inhibitor, with the use of ethylene-vinyl-acetate (ELVAX) 40, a non-biodegradable, non-inflammatory sustained-release polymer. This study shows that orthodontic tooth movement can be inhibited with the use of matrix metalloproteinase inhibitors, and suggests a mechanistic link between matrix metalloproteinase activity and the production of RGD peptides.

Effects of echistatin and an RGD peptide on orthodontic tooth movement.

We tested whether orthodontic tooth movement (OTM) could be blocked by local administration of echistatin or an arginine-glycine-aspartic acid (RGD) peptide, agents known to perturb bone remodeling, adjacent to maxillary molars in rats. These molecules were incorporated into ethylene-vinyl acetate (ELVAX), a non-biodegradable, sustained-release polymer. In vitro experiments showed that the echistatin and RGD peptide were released from ELVAX in active forms at levels sufficient to disrupt osteoclasts. Biotinylated RGD peptide was released from ELVAX into the PDL after surgical implantation. ELVAX loaded with either RGD peptide or echistatin and surgically implanted next to the maxillary molars inhibited orthodontic tooth movement (p < 0.01). The RGD peptide also reduced molar drift (p < 0.05). This study shows the feasibility of using ELVAX to deliver integrin inhibitors adjacent to teeth to limit local tooth movement in response to orthodontic forces.

Immediate early-gene induction in rat osteoblastic cells after mechanical deformation.

Previous studies have reported changes in proliferation, second-messenger generation and activation of various cellular processes when osteoblasts have been mechanically stimulated. Recent evidence suggests that mechanical loading of long bones induces immediate early-gene expression. Immediate early genes, such as Egr-1, are genes that control cell proliferation, are involved in signal transduction, and share properties of transcription factors. The purpose of this study was to examine how mechanical deformation of osteoblasts affects cellular proliferation and Egr-1 mRNA induction. Osteoblasts were isolated from collagenase digestion of newborn rat calvariae, cultured in Petri dishes with flexible bottoms and then constantly stretched, producing an increase of 3 or 7% in surface area. A mechanical stretch of 7% for 0.5 or 24 h resulted in a doubling of [3H]thymidine incorporation, while 50 nM of epidermal growth factor resulted in a 4-fold increase. A time-course experiment showed that a 7% stretch induced Egr-1 mRNA as early as 15 mm, reaching maximum levels by 60 min and returning to baseline by 120 min. Epidermal growth factor at 50 nM for 60 min resulted in a 3.8-fold Egr-1 mRNA induction. A mechanical stretch of 3% for 30 min also produced an Egr-1 mRNA induction. No induction of Egr-1 mRNA was seen in osteoblasts that were exposed to conditioned media from deformed cells. It is concluded that the immediate early gene, Egr-1, may be directly involved in the signal-transduction pathway of mechanical stimuli in osteoblasts.

Effects of surgical ovariectomy on rat salivary gland function.

Studies sought to determine whether there are specific changes in salivary gland protein synthesis and secretion in response to hormone deficiency caused by ovariectomy of female rats. After 50 days, the wet weights of the parotid and submandibular glands did not change with hormone loss while that of the sublingual gland increased by 26% when compared to sham-operated controls. Amylase activity in the parotid declined, as did the level of enzyme activity present in saliva. The amount of the acidic proline-rich protein in the parotid was not altered after ovariectomy when compared to control sham-operated animals, using constant quantities of lysate protein. The total of secreted protein per unit volume did not change with ovariectomy. However, sodium dodecylsulphate-polyacrylamide gel electrophoresis of whole saliva showed the loss of a substantial number of proteins, including amylase and the acidic proline-rich proteins, from the experimental group. Epidermal growth factor concentrations were not significantly altered in the submandibular gland, while again showing a decrease in the concentration from saliva in ovariectomized rats.

Maintenance of soft tissue changes after rigid versus wire fixation for mandibular advancement, with and without genioplasty.

OBJECTIVE: This multisite prospective randomized clinical trial examined 2-year longitudinal soft tissue profile changes after bilateral sagittal split osteotomy for mandibular advancement by using rigid or wire fixation, with and without genioplasty. STUDY DESIGN: The study sample consisted of 127 subjects. The rigid-fixation group (n = 78) received 2-mm bicortical position screws, whereas the wire-fixation group (n = 49) received inferior border wires. In the rigid-fixation group, 35 subjects underwent genioplasty, whereas 24 subjects underwent genioplasty in the wire-fixation group. Soft tissue profile changes of labrale inferius, B-point, and pogonion were obtained from digitized cephalometric films taken immediately before surgery and up to 2 years after surgery. RESULTS: Regardless of fixation technique, subjects who had genioplasty in conjunction with the mandibular advancement had the largest surgical movement and the largest postsurgical change (P <.05). When all variables were constant, fixation technique was associated with maintenance of soft tissue change. Subjects who underwent rigid fixation maintained more soft tissue change than patients who underwent wire fixation. CONCLUSIONS: These findings suggest that subjects undergoing rigid fixation and genioplasty maintained the most soft tissue advancement.

Mandibular range of motion after bilateral sagittal split ramus osteotomy with wire osteosynthesis or rigid fixation.

OBJECTIVES: An analysis was conducted to compare mandibular range of motion among Class II patients treated with wire osteosynthesis or rigid internal fixation after surgical mandibular advancement. STUDY DESIGN: Patients randomly received wire osteosynthesis and 8 weeks of maxillomandibular fixation (n = 49) or rigid internal fixation (n = 78). Mandibular range of motion was measured 2 weeks before surgery and 8 weeks, 6 months, and 1, 2, and 5 years after surgery. RESULTS: Both groups showed decreased mobility in all movement dimensions that progressively recovered to near presurgical levels over the 5-year follow-up period. The difference in range of motion between treatment groups was not statistically significant. Changes in proximal and distal segment position could not explain decreased mobility. CONCLUSIONS: Similar decreases in mandibular mobility occurred with wire and rigid fixation of a bilateral sagittal split ramus osteotomy after surgery. Long-term changes were statistically, but not clinically, significant.

Technical factors accounting for stability of a bilateral sagittal split osteotomy advancement: wire osteosynthesis versus rigid fixation.

OBJECTIVE: Relapse after bilateral sagittal split osteotomy has been attributed to various technical factors that are inherent in the surgical procedure. The purpose of this article was to analyze technical factors that predispose to relapse when wire or rigid fixation is used. STUDY DESIGN: Patients were randomized to either rigid or wire osteosynthesis. Cephalometric radiographs were obtained and digitized at multiple time periods before and after surgery. Data were analyzed through use of 2-sample t tests and stepwise regression analyses. RESULTS: Multivariate analysis indicated that the following factors correlated with relapse: initial advancement, change in ramus in inclination, change in the mandibular plane, and fixation type. CONCLUSIONS: Relapse increased with the amount of initial advancement and, to a lesser extent, with control of the proximal segment and change in the mandibular plane. These factors are similar for wire osteosynthesis and rigid fixation.

Correction of posterior crossbite.

Posterior crossbites, which can range from a single tooth to a bilateral constriction of the maxilla, can be detected easily on clinical exam. This article reviews the etiology, differential diagnosis and treatment of posterior crossbite. Several appliances and their uses are discussed.

Bis-enoxacin inhibits bone resorption and orthodontic tooth movement.

UNLABELLED: Enoxacin inhibits binding between the B-subunit of vacuolar H(+)-ATPase (V-ATPase) and microfilaments, and also between osteoclast formation and bone resorption in vitro. We hypothesized that a bisphosphonate derivative of enoxacin, bis-enoxacin (BE), which was previously studied as a bone-directed antibiotic, might have similar activities. BE shared a number of characteristics with enoxacin: It blocked binding between the recombinant B-subunit and microfilaments and inhibited osteoclastogenesis in cell culture with IC50s of about 10 µM in each case. BE did not alter the relative expression levels of various osteoclast-specific proteins. Even though tartrate-resistant acid phosphatase 5b was expressed, proteolytic activation of the latent pro-enzyme was inhibited. However, unlike enoxacin, BE stimulated caspase-3 activity. BE bound to bone slices and inhibited bone resorption by osteoclasts on BE-coated bone slices in cell culture. BE reduced the amount of orthodontic tooth movement achieved in rats after 28 days. Analysis of these data suggests that BE is a novel anti-resorptive molecule that is active both in vitro and in vivo and may have clinical uses. ABBREVIATIONS: BE, bis-enoxacin; V-ATPase, vacuolar H(+)-ATPase; TRAP, tartrate-resistant acid phosphatase; αMEM D10, minimal essential media, alpha modification with 10% fetal bovine serum; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; RANKL, receptor activator of nuclear factor kappa B-ligand; NFATc1, nuclear factor of activated T-cells; ADAM, a disintegrin and metalloprotease domain; OTM, orthodontic tooth movement.

Psychosis Incident Cohort Outcome Study (PICOS). A multisite study of clinical, social and biological characteristics, patterns of care and predictors of outcome in first-episode psychosis. Background, methodology and overview of the patient sample.

AIMS: This paper aims at providing an overview of the background, design and initial findings of Psychosis Incident Cohort Outcome Study (PICOS). METHODS: PICOS is a large multi-site population-based study on first-episode psychosis (FEP) patients attending public mental health services in the Veneto region (Italy) over a 3-year period. PICOS has a naturalistic longitudinal design and it includes three different modules addressing, respectively, clinical and social variables, genetics and brain imaging. Its primary aims are to characterize FEP patients in terms of clinical, psychological and social presentation, and to investigate the relative weight of clinical, environmental and biological factors (i.e. genetics and brain structure/functioning) in predicting the outcome of FEP. RESULTS: An in-depth description of the research methodology is given first. Details on recruitment phase and baseline and follow-up evaluations are then provided. Initial findings relating to patients' baseline assessments are also presented. Future planned analyses are outlined. CONCLUSIONS: Both strengths and limitations of PICOS are discussed in the light of issues not addressed in the current literature on FEP. This study aims at making a substantial contribution to research on FEP patients. It is hoped that the research strategies adopted in PICOS will enhance the convergence of methodologies in ongoing and future studies on FEP.

Thrombin's effects on osteoblastic cells. I. Cytosolic calcium and phosphoinositides.

Thrombin, a blood coagulation factor, has been shown to be a very effective in vitro bone resorbing agent whose mechanism of action on osteoblastic cells remains to be elucidated. In the present study, the effects of highly purified human thrombin on Saos-2 and G292 cells, two human osteoblast-like osteosarcoma cell lines, were investigated. Thrombin (0.6-16 U/ml) caused a significant, dose-dependent increase in osteoblastic cell proliferation. Thrombin also elicited a dose-dependent increase in cytosolic calcium concentration in both Saos-2 and G292 cells (maximal increases were 38% and 200% over baseline, respectively). Addition of thrombin to the osteoblast-like cells resulted in significant time- and dose-dependent changes in phosphoinositide levels: the percentage of inositol monophosphate levels were decreased, whereas the percentage of inositol bisphosphate, inositol trisphosphate and inositol tetrakisphosphate levels were increased. The relative magnitude of the changes in phosphoinositide levels was similar to the changes in cytosolic calcium concentration. These results suggest that thrombin's mechanism of action on bone cells may involve increases in cytosolic calcium levels and in phosphoinositide metabolism.

The effects of sialoadenectomy and exogenous EGF on taste bud morphology and maintenance.

Taste buds on the dorsal tongue surface are continually bathed in saliva rich in epidermal growth factor (EGF). In the following experiment, taste bud number and morphology were monitored following submandibular and sublingual salivary gland removal (sialoadenectomy), to determine if EGF plays a role in the maintenance and formation of taste buds. Adult male rats were divided into four groups: sialoadenectomized (SX, n = 4); sialoadenectomized with EGF replacement (SX + EGF, n = 5); sham-operated (SH, n = 4); and sham-operated with exogenous EGF (SH + EGF, n = 5). After a 3 week recovery, SX + EGF and SH + EGF animals were given 50 microg/day EGF in their drinking water for 14 days. At day 14, saliva was collected, the animals were killed and the presence of EGF determined by radioligand-binding assay. Tongues were removed and histologically examined for the presence and morphology of taste buds on fungiform and circumvallate papillae, or immunostained for the presence of EGF, TGFalpha (transforming growth factor alpha) and EGFR (EGF receptor). The removal of submandibular and sublingual salivary glands resulted in the loss of fungiform taste buds and normal fungiform papillae morphology. These effects were reversed by EGF supplementation, indicating a role for EGF in fungiform taste bud maintenance. In addition, supplementation of EGF to sham-operated animals increased the size of fungiform taste buds. In contrast, removal of salivary glands had no effect on the size, numbers, or morphology of circumvallate taste buds, suggesting that the formation and maintenance of taste buds in fungiform and circumvallate papillae may involve different and distinct processes. EGF, TGFalpha and EGFR were localized to distinct layers of the dorsal epithelium and to within both fungiform and circumvallate taste buds. Their expression within the epithelium or taste buds was not altered with sialoadenectomy, indicating that the actions of endogenous EGF and TGFalpha are distinct and not regulated by exogenous EGF and TGFalpha supplied in saliva.