A survey of undergraduate orthodontic training and orthodontic practices by general dental practitioners.

PURPOSE OF THE STUDY: To assess satisfaction with undergraduate orthodontic training, the variety of treatments undertaken in general practice, practitioners' perceived competence in orthodontics and the level of interest in continuing education in orthodontics. DESIGN: Cross-sectional questionnaire-based study. MATERIALS AND METHODS: A questionnaire was mailed to 520 general practitioners in Dublin, Kildare and Wicklow as listed in Irish Dental Council Register of Dentists 2003. RESULTS: Forty-six percent of dentists responded. More than half (54 per cent) of the respondents were satisfied with both academic and clinical aspects of undergraduate training. Twenty-nine percent regularly perform orthodontic treatment. Only 60 percent feel comfortable treating orthodontic emergencies. Over 70 percent have either already attended or aspire to attend further training in orthodontic diagnosis and interceptive orthodontics. CONCLUSIONS: Our study indicates that in the greater Dublin area, graduates (those qualified less than 10 years) are increasingly satisfied with undergraduate teaching. Orthodontic treatment is performed regularly in general dental practice with interceptive procedures most often carried out. While ability to deal with orthodontic emergencies is not universal, practitioners do appear confident to perform a variety of orthodontic procedures. Interest in continuing education in orthodontics is very high. Our study indicates that participation in continuing education in orthodontics appears to translate into greater provision of orthodontic care in general practice.

The KBG syndrome, characteristic dental findings: a case report.

Short stature and developmental delay may be observed in many genetic conditions and well-defined syndromes. A 7-year-old girl presented with the non-specific findings of subtle dysmorphism, short stature and developmental delay. Although a genetic syndrome was suspected, a definitive diagnosis was not made until the dental findings of KBG syndrome were recognised, namely grossly enlarged maxillary permanent central incisors and hypodontia.

Odontogenic keratocysts in a 5-year-old: initial manifestations of nevoid basal cell carcinoma syndrome.

The purpose of this paper is to report the occurrence of odontogenic keratocysts in a young child. Odontogenic keratocysts are one of the principal features of nevoid basal cell carcinoma syndrome. Their occurrence in this syndrome is usually during the second or third decades of life. This report describes the occurrence of odontogenic keratocysts in a 5-year-old, which proved to be the initial presentation of nevoid basal cell carcinoma syndrome and highlights the need to consider this syndrome as a possible diagnosis in all cases of odontogenic keratocysts.

Talc induces apoptosis in human malignant mesothelioma cells in vitro.

Pleurodesis with talc is an accepted method for the treatment of symptomatic pleural effusions secondary to mesotheliomas. Patients with mesothelioma who have talc-induced pleurodesis have a lower morbidity than do those who do not have pleurodesis. The mechanisms whereby talc mediated these effects were considered to be secondary to a decrease or absence of a pleural effusion. The possibility that talc may directly affect malignant cells was not considered. The present study was designed to evaluate if talc directly effects cell death of malignant mesothelioma cells (MMC) or normal pleural mesothelial cells (PMC). Three confluent MMC and PMC were exposed to talc for 24, 48, and 72 h. In parallel experiments, glass beads similar in size to talc were included as control. Apoptosis was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) and DNA electrophoresis. Our results demonstrated that talc at a therapeutically achievable concentration (6 microg/cm(2)) induces significant apoptosis in MMC. Talc-induced maximum apoptosis in MMC (39.50 +/- 2.55%, 31.87 +/- 4.69%, and 15.10 +/- 3.93% in CRL-2081, CRL-5820, and CRL-5915, respectively) at 48 h, which was significantly (p < 0.05) greater than that in control cells. Electrophoresis of DNA isolated from talc-exposed MMC demonstrated the typical ladder pattern of internucleosomal DNA cleavage. Talc did not induce apoptosis in PMC, and glass beads did not cause significant apoptosis in either MMC or PMC. The present study has demonstrated that talc induces apoptosis in MMC without affecting normal mesothelial cells of the pleura.

An ex-vivo investigation into the effect of bracket displacement on the resistance to sliding.

This ex-vivo study investigated the effect that repeated bracket displacement has on sliding friction and the magnitude of bracket displacement, and hence tooth movement, required to release bracket/archwire binding. The design consisted of an ex-vivo laboratory study. A jig was designed that allowed repeated displacement of a bracket to occur, while the resistance to sliding (friction) was measured using an Instron universal testing machine. One type of stainless steel bracket was used in conjunction with four archwire types (0.016-inch stainless steel, 0.019 x 0.025-inch stainless steel, 0.021 x 0.025-inch stainless steel, 0.019 x 0.025-inch beta-titanium) and four magnitudes of displacement. Repeated bracket displacement has a significant effect on the sliding resistance at the bracket/archwire interface (P < 0.001). The reduction in sliding resistance noted with displacement depended on the archwire. Over the range of displacements tested, there was an 85 and 80 per cent reduction associated with 0.021 x 0.025-inch and 0.019 x 0.025-inch stainless steel, respectively. For 0.019 x 0.025-inch beta-titanium and 0.016-inch stainless steel, these reductions were 27 and 19 per cent, respectively. The importance of true friction, given the likelihood of bracket and/or archwire displacements in vivo, may be lessened.

Cell-free transfer of the vesicular stomatitis virus G protein from an endoplasmic reticulum compartment of baby hamster kidney cells to a rat liver Golgi apparatus compartment for Man8-9 to Man5 processing.

We report the reconstitution of the transfer of a membrane glycoprotein (vesicular stomatitis virus glycoprotein, VSV-G protein) from endoplasmic reticulum to Golgi apparatus and its subsequent Man8-9GlcNAc2 to Man5GlcNAc2 processing in a completely cell-free system. The acceptor was Golgi apparatus from rat liver immobilized on nitrocellulose. The endoplasmic reticulum donor was from homogenates of VSV-G-infected BHK cells. Nucleoside triphosphate plus cytosol-dependent transfer and processing of radiolabeled VSV-G protein was observed with donor from BHK cells infected at 37 degrees C with wild-type VSV or at the permissive temperature of 34 degrees C with the ts045 mutant. With Golgi apparatus as acceptor, specific transfer at 37 degrees C in the presence of nucleoside triphosphate was eightfold that at 4 degrees C or in the absence of ATP. About 40% of the VSV-G protein transferred was processed to the Man5GlcNAc2 form. Processing was specific for cis Golgi apparatus fractions purified by preparative free-flow electrophoresis. Fractions derived from the trans Golgi apparatus were inactive in processing. With the ts045 temperature-sensitive mutant, transfer and processing were much reduced even in the complete system when microsomes were from cells infected with mutant virus and incubated at the restrictive temperature of 39.5 degrees C but were able to proceed at the permissive temperature of 34 degrees C. Thus, Man8-9GlcNAc2 to Man5GlcNAc2 processing of VSV-G protein occurs following transfer in a completely cell-free system using immobilized intact Golgi apparatus or cis Golgi apparatus cisternae as the acceptor and shows temperature sensitivity, donor specificity, requirement for ATP, and response to inhibitors similar to those exhibited by transfer and processing of VSV-G protein in vivo.

Interleukin 8: an autocrine growth factor for malignant mesothelioma.

Interleukin 8 (IL-8) is a potent chemokine that also has a direct growth-potentiating effect on certain tumors. In the present study, we determined IL-8 levels in human malignant mesothelioma (MM) effusions and congestive heart failure pleural fluids. We also investigated antigenic IL-8 production by different MM cell lines, and we describe the role of IL-8 in the autocrine growth regulation of MMs. Mesothelial (CRL-9444 = MC) and MM (CRL-2081 = MM-1, CRL-5915 = MM-2, and CRL-5820 = MM-3) cell lines were grown using standard culture methods. The bioactive IL-8 levels were measured in supernatants of cultured cells by ELISA, and the expression of cell-associated immunoreactive IL-8 was observed by immunohistochemistry. The proliferative activity was determined by thymidine ([3H]thymidine) incorporation and also by direct cell counts after incubation with varying concentrations of IL-8 in the presence/absence of specific polyclonal IL-8 antibody. We found significantly higher levels of IL-8 in mesothelioma pleural fluids than congestive heart failure and a time-dependent increase in IL-8 levels in MM-1 and MM-2 cell supernatants during 96 h of incubation. IL-8 levels were nearly undetectable in MM-3 and MC cell line supernatants. In MM-1 and MM-2 cells, IL-8 caused a dose-dependent increase of [3H]thymidine incorporation to maximal levels of 46.3 +/- 3.6% and 12.3 +/- 1.6% (P < 0.001), respectively, when compared with serum-free medium as control. Neutralization of IL-8 significantly decreased proliferative activity of MM-1 and MM-2. IL-8 did not induce proliferative activity in MM-3 and MC cells. We conclude that IL-8 had a direct growth-potentiating activity in MMs.

A case report of pre-eruptive coronal resorption in a mandibular canine.

A case of intracoronal resorption in a recently erupted mandibular canine in an 11-year-old girl is presented. Possible aetiology and approaches to treatment of such lesions are discussed.

Duration of orthodontic treatment involving orthognathic surgery.

The purpose of this study was to analyze factors influencing the duration of treatment in a sample of patients treated by a combined orthodontic/orthognathic surgery approach. Presurgical and postsurgical treatment times were assessed for 315 patients processed through an orthognathic team over a 7-year period. The median total treatment duration for all patients was 21.9 months, the median presurgical duration was 15.4 months, and the median postsurgical duration was 5.9 months. Treatment involving extractions resulted in significantly increased presurgical and total treatment times. Treatments performed in the university clinic showed reduced presurgical duration and increased postsurgical duration compared to treatments carried out by specialists outside the university. Presurgical, postsurgical, and total treatment times were significantly reduced when the orthodontist had treated 10 or more patients during the period. An earlier regimen of orthodontic treatment did not appear to have a significant effect on treatment duration.

Bilateral pulmonary aspiration of intact teeth following maxillofacial trauma.

Tooth aspiration is one of the rare sequelae of dental trauma. When this does occur, the right bronchus is usually involved in adults due to the anatomical configuration. In this unusual case, two teeth were aspirated with one entering each lung. While the outcome from cases of aspiration of foreign bodies is usually favourable, this case serves to illustrate one of the possible unfavourable consequences.

An investigation into the behavioural characteristics of orthodontic elastomeric modules.

The object of the study was to investigate the behavioural characteristics of orthodontic elastomeric modules with regard to their effect on frictional resistance and their failure load forces, and involved the use of an experimental laboratory-based study. Six cohorts were assembled employing five types of module and two bracket types. Straight lengths of 0.018 x 0.025-inch stainless steel were pulled through the ligated brackets and frictional resistance was measured using an Instron universal testing machine. Recordings were repeated over a 4-week period, during which time the cohorts were placed in a simulated oral environment. Failure load forces of new and used modules were also recorded, and frictional resistance and failure load forces. Analysis of variance revealed that the Minitwin cohort exhibited significantly higher frictional resistance and that the clear modules demonstrated the lowest levels of friction. Time soaked in a simulated oral environment had a variable effect on frictional resistance. A wide range of failure load forces was seen for the five types of module and all types showed a reduction in failure load force following their soaking in the simulated oral environment. There was variation in performance of the different modules both in friction testing and failure load testing.

Eastern Health Board Regional Orthodontic Service: an initial audit.

This initial audit of 600 recently assessed Eastern Health Board orthodontic patients suggests that a large number of them (47 per cent) requires referral for routine restorative and preventive dental care. Closer links are needed with general dental practitioners and community dental surgeons to resolve these needs. The trend for a high referral of females and Class 11 Division 1 malocclusion type correlated well with studies in other countries.

Membrane fusion as a determinant of the infectibility of cells by vesicular stomatitis virus.

When rat embryo fibroblasts (REF) and BHK21 cells were treated with VSV at the same m.o.i., 8- to 10-fold fewer REF were infected than BHK21 cells; REF also showed a similar decrease in the production of progeny virions per cell. When other aspects of the infectious cycle were studied in the two cells, it was found that the time course of virus production was similar in BHK21 cells and REF, virus grown in REF showed the same infectivity in both cell types as virus grown in BHK21 cells, and all REF in a culture could eventually be infected. There was virtually no difference in the binding of VSV to the cells, and REF actually internalized virus at a slightly greater rate than BHK21 cells. Direct fusion of VSV with the plasma membrane of the two cell types resulted in infection of the cells, but did not abolish the difference in infectibility. When this fusion was quantitated using 125I-VSV, BHK21 cells fused 6-fold more virus than REF, a difference that accounts for most of the difference in the infectibility of the two cell types. The results indicate that constituents of the host cell plasma membrane modulate the fusion of VSV.

Sequential disassembly of the cytoskeleton in BHK21 cells infected with vesicular stomatitis virus.

The cytopathic effects of vesicular stomatitis virus (VSV) that result in the rounding of BHK21 cells have been studied. The results indicate that they are mediated by a sequential alteration in the distribution of the components of the cytoskeleton, an effect that requires the expression of the viral L protein. The constituents of the cytoskeleton of BHK21 cells were analyzed by fluorescence microscopy. Actin filaments were the first component to become disorganized, so that disassembly of stress fibers were detected 1 hr after infection. The distribution of microtubules and intermediate filaments was unchanged at 2 hr after infection; however, both these cytoskeletal elements exhibited an altered distribution at 3-4 hr after infection. Actinomycin D and cycloheximide did not cause the same effects as infection with VSV, suggesting that inhibition of host-cell gene expression was not responsible. However, viral gene expression was required, since cells infected with uv-irradiated VSV showed the same distribution of cytoskeletal constituents as mock-infected controls. Cells infected at 39.5 degrees (the nonpermissive temperature) with mutants of VSV temperature sensitive in the viral NS (ts G22), N(ts G41), M(ts 0 23), and G(ts 0 45) proteins showed the same changes in the cytoskeleton as those detected with wild-type virus. In contrast, cells infected with ts G11 (L-) showed the characteristic effect of VSV on the cytoskeleton when incubated at 34 degrees (the permissive temperature), but not when incubated at 39.5 degrees. The T-1026 R1 mutant of VSV, which has a much less dramatic effect on cell morphology than wild-type virus, also caused a less marked disruption of the cytoskeleton.

Cellular mechanisms in the superinfection exclusion of vesicular stomatitis virus.

The superinfection exclusion of VSV has been studied and found to be caused by a combination of three distinct effects on endocytosis by VSV-infected cells: first, a decreased rate of formation of endocytic vesicles as judged by an inhibition of fluid-phase uptake at 2 hr postinfection; second, a decreased rate of internalization of receptor-bound ligands, which was detected at 4 hr postinfection; and third, a competition with newly synthesized virus for occupancy of coated pits, as indicated by electron microscopy of infected cells. At the same time that fluid-phase uptake decreased, numerous uncoated invaginations were observed at the cell surface.

Stress-induced increase of hexose transport as a novel index of cytopathic effects in virus-infected cells: role of the L protein in the action of vesicular stomatitis virus.

The VSV-specific increase in hexose transport by BHK cells has been measured by assay of the [3H]dGlc/[14C]AIB uptake ratio. The effect was abolished by uv-irradiation of the virus, indicating that viral gene expression is required. Cells infected with the T1026 R1 mutant of VSV, which causes only slight cytopathic changes, exhibited only a slight increase in hexose uptake. Cells infected with temperature-sensitive (ts) mutants of VSV that are defective in the function of the viral N, NS, G, or M proteins at the restrictive temperature (39.5 degrees) exhibited increased [3H]dGLC/[14C]AIB uptake ratios typical of wild-type virus at either restrictive (39.5 degrees) or permissive temperature (34 degrees). Cells infected with a mutant defective in the function of the viral L protein exhibited an increased [3H]dGlc/[14C]AIB uptake ratio at permissive temperature (34 degrees) only; at restrictive temperature (39.5 degrees) the uptake ratio was essentially the same as that of mock-infected cells. Temperature-shift experiments indicated that the effect on hexose transport persisted for at least 6 hr in cells which no longer expressed function L protein, and that when expression of L was restricted to the first 2 hr of infection, an almost complete stimulation of hexose transport was observed 4 hr later. These results indicate that expression of the L gene is a necessary factor for inducing an increased hexose uptake in VSV-infected BHK cells. They also suggest that the action of the L protein on hexose transport is indirect, and is presumably mediated by other cellular constituents. The studies support the concept that an increased dGlc uptake may be a useful index of the cytopathic consequences of virus infection.

Stress induces an increased hexose uptake in cultured cells.

Temperature-sensitive mutants have revealed a region of the herpes simplex virus 1 genome that affects both the uptake of hexose and the synthesis of heat shock proteins. Other inducers of heat-shock proteins, namely heat shock itself and arsenite, likewise induce an increased uptake of hexose. The increased uptake, like that induced by insulin, is insensitive to the presence of actinomycin D or cycloheximide. It is concluded that an increased hexose uptake, reflecting an activation or relocation of existing hexose transport protein, is a general biochemical response of stressed cells.