Customized palatal guide and splint for maxillary expansion.

Customization in orthognathic surgery allows better precision and a reduced surgical time. In Le Fort I osteotomy surgery, the maxillary segmentation is considered one of the most unstable procedures due to transverse instability. Various different types of palatal device have been proposed to address this instability. This note describes a customized bone-borne palatal guide and splint that may help surgeons shorten the surgical time and achieve better three-dimensional repositioning, with more postoperative comfort for the patient and occlusal control for the surgeon.

Assessment of condylar changes after orthognathic surgery using computed tomography regional superimposition.

This study aimed to investigate the effects of bimaxillary advancement orthognathic surgery on the condylar remodeling of the temporomandibular joint (TMJ) using voxel-based regional superimposition of cone-beam computed tomography (CBCT). In this retrospective study, the sample comprised 56 condyles from 28 healthy patients (aged from 16 to 50years) with mandibular retrognathism treated with bimaxillary advancement. CBCT scans were taken preoperatively and at 14.3±4.2months postoperatively. The scans at the two time points were superimposed using regional voxel-based registration to assess condylar changes in the follow-up period. The linear alterations were measured in six different areas of each condyle to determine the pattern of condylar remodeling. Although no significant correlation was observed between changes in condylar surfaces, bone resorption occurred predominantly in the posterior and superior regions, while bone formation was predominantly on the anterior surface. Medial and lateral surfaces presented fewer bone changes. The overall bone changes were smaller than 1mm bilaterally in 21 patients (75%) and, considering each condyle individually, were smaller than 1mm in 48 condyles (85.7%). The results suggested that mild condylar remodeling in healthy patients is a common finding after orthognathic surgery. Future studies may clarify the mechanisms involved in the remodeling and help to understand the reasons for the remodeling pattern.

Spin label EPR suggests the presence of cholesterol rich domains in cultured insect cell membranes.

Different spin labels were incorporated to the membranes of cultured insect UFL-AG-286 cells in order to characterize their physical properties by Electron Paramagnetic Resonance spectroscopy (EPR). The spectrum of the spin label 12-SASL incorporated to cell membranes was similar as those obtained in membrane model systems composed of eggPC/cholesterol. However, the spectrum of the spin label CSL, chemically related to cholesterol, was drastically different in the two systems. Interestingly, when cell cholesterol content was reduced using methyl beta cyclodextrin, an EPR spectrum similar to those of model membranes was obtained. The analysis of these experiments suggests the existence of cholesterol rich regions in UFL-AG-286 cell membranes.

Three-dimensional maxillary and mandibular regional superimposition using cone beam computed tomography: a validation study.

This study aimed to validate a novel method for fast regional superimposition of cone beam computed tomography (CBCT) scans. The method can be used with smaller field of view scans, thereby allowing for a lower radiation dose. This retrospective study used two dry skulls and secondary data from 15 patients who had more than one scan taken using the same machine. Two observers tested two types of regional voxel-based superimposition: maxillary and mandibular. The registration took 10-15s. Three-dimensional surface models of the maxillas and mandibles were generated via standardized threshold segmentation, and the accuracy and reproducibility of the superimpositions were assessed using the iterative closest point technique to measure the root mean square (RMS) distance between the images. Five areas were measured and a RMS≤0.25 was considered successful. Descriptive statistics and the intra-class correlation coefficient (ICC) were used to compare the intra-observer measurement reproducibility. The ICC was ≥0.980 for all of the variables and the highest RMS found was 0.241. The inter-observer reproducibility was assessed case by case and was perfect (RMS 0) for 68% (23 out of 34) of the superimpositions done and not clinically significant (RMS≤0.25) for the other 32%. The method is fast, accurate, and reproducible and is an alternative to cranial base superimposition.

Management of the severely resorbed maxilla using Le Fort I osteotomy.

The severely resorbed maxilla poses difficulties for patient rehabilitation. This condition is characterized by the absence of bone for implant therapy and a reversed maxillomandibular relationship. Treatment for this condition is well established, but the correct time for reconstruction, implant therapy and Le Fort I osteotomy may vary. This paper describes a three-step procedure for the management of the severely resorbed maxilla. The three steps are: maxillary bone reconstruction; implant placement and building a fixed prosthesis in class III occlusion; followed by orthognathic surgery.

Predictability of maxillary repositioning during bimaxillary surgery: accuracy of a new technique.

The purpose of this retrospective study was to evaluate the predictability of maxillary repositioning following Le Fort I osteotomy during bimaxillary surgery using a new technique with splints to reposition the maxilla in the three planes of space. In order to assess the accuracy of horizontal and vertical maxillary movements of the maxilla, 32 consecutive patients who underwent bimaxillary surgery had their predictive tracings and model surgery measures compared to postoperative cephalograms taken 1 week after surgery. There was a strong positive correlation between model surgery and postoperative result: 53% of horizontal movements and 41% of vertical movements showed less than 0.2 mm variation. When predictive tracings were compared to postoperative results 44% of horizontal and 50% of vertical movements showed less than 0.2 mm variation. There was no significant difference (P>0.05) between the planned and actual maxillary positions in the sample evaluated. This technique for maxillary repositioning during two-jaw surgery proved to be effective and predictable, with strong agreement between predictive tracings, model surgery and postoperative results.

Evaluation of the diagnostic value of measuring IgG, IgM and IgA antibodies to the recombinant 16-kilodalton antigen of mycobacterium tuberculosis in childhood tuberculosis.

OBJECTIVE: To evaluate the usefulness of the recombinant 16-kDa antigen (re-Ag16) of Mycobacterium tuberculosis in the serodiagnosis of tuberculosis (TB) in children. MATERIALS: Seventy-four children with active TB, 49 apparently healthy contact children and 149 children suffering from non-mycobacterial diseases were evaluated. Detection of anti 16-kDa antigen IgG, IgM and IgA was performed by enzyme-immunoassay. RESULTS: An increased mean antibody response to re-Ag16 was observed in contact children compared with non-mycobacterial disease patients (IgG assay: 89.1 enzymatic units [eu] vs. 40.8 eu; IgM assay: 64.7 eu vs. 38.1 eu; IgA assay: 138.2 eu vs. 78.2 eu for contact children and non-mycobacterial disease patients, respectively), indicating that anti-16-kDa antibodies could be elevated in response to infections even without clinically apparent TB. Setting the specificity as the 95th percentile of the contact group's ELISA units, the sensitivity of the IgG, IgA and IgM assays were 34%, 19% and 3% respectively; combining results of the IgG and IgA assays led to 43% positivity in children with active TB. CONCLUSION: The detection of anti 16-kDa IgG and IgA may be useful as a complementary technique for the diagnosis of childhood TB. Recognition of this antigen seems to be heterogeneous; combining responses against other antigens may be a good strategy to improve the performance of this assay.

Anticarsia gemmatalis nuclear polyhedrosis virus replication in serum-free and serum-reduced insect cell cultures.

In order to develop a financially feasible process to produce Anticarsia gemmatalis Nuclear Polyhedrosis virus in cell culture, we developed a lipidic supplement to replace fetal calf serum in insect cell culture media. The supplement, prepared with an extract of lipids from hen egg yolk, allowed us to reduce the contents of serum in the culture medium from 10% to 1%. IPLB-Sf-21 cells could be kept along consecutive passages in serum-reduced medium. The replication of AgNPV in HEYLE-supplemented cultures was evaluated. Extracellular virions production was the same as in FCS-supplemented-cultures, but the production level of polyhedral inclusion bodies was significantly lowered in HEYLE-supplemented cultures. The reduced production of PIBs is related to a premature releasing of non-occluded particles as well as to a reduced synthesis of polyhedrin protein.