Epidemiology of Adult Uveitis in a Northern Ireland Tertiary Referral Centre.

Uveitis is inflammation of the middle layer of the eye, called the uveal tract. It can be classified by anatomic location of the focus of inflammation inside the eye: intermediate, posterior or pan-uveitis. These types are less common than anterior uveitis (iritis), but more often have underlying aetiologies that require identification. Some aetiologies are infective, while others require systemic immunosuppression. Underlying aetiologies vary in different regions in the world, and so local data is important to guide clinicians. This study describes the aetiology of 255 cases of intermediate, posterior and pan-uveitis in adults. The most common non-infectious causes, after idiopathic, were sarcoid, Birdshot chorioretinopathy, demyelination-related and Behçet's, whereas toxoplasmosis and herpes simplex and zoster related retinitis were the common infectious causes. Neither age nor sex of the patient were related to aetiology.

Magnetic resonance imaging assessment of a sinus lift operation using reoxidised cellulose (Surgicel) as graft material.

Various materials have been used for bone grafts in the sinus lift operation, to increase the vertical bone height in the maxilla before the placement of dental implants in the atrophic maxilla. In this case history, Surgicel (oxidised regenerated cellulose) was used as a graft material for one patient, allowing successful delayed implant placement within new and existing bone. The sinus region was examined three months after grafting with Surgicel using magnetic resonance imaging (MRI). The MR images showed that material of similar MR signal to bone had formed within the graft. MRI allowed us to gain tomographic information of the region without exposure of the patient to ionising radiation. The formation of bone within the Surgicel matrix was confirmed at implant placement. This poses interesting questions as to the physiology of bone formation within non-particulate graft material, warranting further investigation.

The use of SPAMM to assess spatial distortion due to static field inhomogeneity in dental MRI.

In planning placement of dental implants using MRI, a SPAMM (spatial modulation of magnetization) magnetization preparation sequence was incorporated into a spin-echo imaging sequence. A phantom was imaged with a ferromagnetic object attached. Spatial distortion due to deviations in Larmor frequency was detected by a deviation of SPAMM lines. Both SPAMM line deviation and interline spacing were found to agree with a deltaB0 map generated from phase images. Imaging of a volunteer with and without typically used metallic implants positioned in a template showed SPAMM line deviations to correlate with expected deviations in vivo. SPAMM lines showed possible distortion due to chemical shift in the bone marrow and the presence of titanium implants to be insignificant. SPAMM may thus be used to provide a qualitative estimate of the accuracy of the MRI image when planning dental implants.

Assessment of maxillary sinus volume for the sinus lift operation by three-dimensional magnetic resonance imaging.

OBJECTIVES: To calculate sinus and bone graft volumes and vertical bone heights from sequential magnetic resonance imaging (MRI) examinations in patients undergoing a sinus lift operation. METHODS: MRI scans were obtained pre-operatively and at 10 days and 10 weeks post-operatively, using a 0.95 tesla MRI scanner and a three-dimensional (3D) magnetisation prepared, rapid acquisition gradient-echo (MP-RAGE) sequence. RESULTS: Estimates of the bone graft volumes required for a desired vertical bone height were made from the pre-operative MRI scan. Measurements of the graft volumes and bone heights actually achieved were made from the post-operative scans. The MRI appearance of the graft changed between the 10 day and 10 week scans. CONCLUSIONS: We have proposed a technique which has the potential to give the surgeon an estimate of the optimum volume of graft for the sinus lift operation from the pre-operative MRI scan alone and demonstrated its application in a single patient. Changes in the sequential MRI appearance of the graft are consistent with replacement of fluid by a matrix of trabecular bone.

Assessment of the sinus lift operation by magnetic resonance imaging.

Sinus lift operations are done to increase bone thickness before placement of osseointegrated implants in areas of the maxilla where there is insufficient bone between the lower border of the maxillary sinus mucosa and the oral mucoperiosteum. Full sectional information should be available to the surgeon before the sinus lift operation so that the outcome can be predicted, and to allow for assessment of the volume of bone graft required. It is also useful to assess the success of the procedure before placement of the implant, and to choose the implant length and orientation required for maximum stability. We describe the use of a 0.2 tesla magnetic resonance imaging (MRI) scanner to image a patient before and after sinus lift. MRI gave full sectional information of the bone on both occasions without using ionizing radiation. The quality of the images was good, and should be considered as an alternative to the accepted gold standard of computed tomography (CT), which exposes the patient to a high dose of radiation.

Low-field magnetic resonance imaging for implant dentistry.

OBJECTIVE: To evaluate the use of a low-field magnetic resonance scanner for assessment of available bone for placement of osseo-integrated dental implants. METHODS: Eleven Patients were examined to assess suitability for implant placement using a 0.2 tesla 'open' scanner. Imaging/surgical templates were constructed, with gadolinium markers to allow accurate location of the implant sites. RESULTS: In all cases, localisation of potential implant sites was easily made and full information in all three planes readily available. Artefacts were few and localised, (noted on one site in one case only). Vital structures (nerves and vessels), and the variable geometry of the floor of the maxillary sinus were clearly seen, and cortical bone delineated from cancellous. The appearance of soft tissues in the scan allowed the surgeon to assess the final profile of the patient. CONCLUSION: Low-field magnetic resonance imaging has definite potential for pre-implant assessment. Full sectional information is readily available at any desired plane with no need for reformatting. The information for accurate and safe implant placement is clear. The technique uses no ionising radiation. Further work is needed to evaluate spatial distortion caused by magnetic susceptibility effects at air/tissue interfaces, but our calculations indicate that at low field, using an appropriate protocol, the effect will not be substantial.

Linking postdoctoral general dentistry programs with managed care programs and settings.

This report presents the results of a small workgroup convened by the American Association of Dental Schools to examine experiences related to postdoctoral general dentistry programs linked with managed care systems and clinical settings. The workgroup was a component of an Association effort to identify and promote innovative and nontraditional methods by which the number of postdoctoral general dentistry (PGD) positions can be increased to meet current demand for PGD education. The participants identified factors and conditions that they believed to be critical to the planning, development, and conduct of PGD programs with substantial linkages with managed care systems and settings. The information should be helpful to others as they consider opportunities to establish PGD programs or increase their number of PGD training positions.

Magnetic resonance imaging: a useful tool for evaluation of bone prior to implant surgery.

OBJECTIVE: To illustrate the potential for use of magnetic resonance imaging (MRI) to gain full sectional information before placement of osseo-integrated dental implants, with no patient exposure to ionising radiation. MATERIALS AND METHODS: Four typical cases are illustrated, the patients being imaged in a one tesla MRI scanner. The setting up of the sequences is explained, along with the use of an imaging/surgical template with gadolinium markers. RESULTS: MRI clearly shows full sectional detail of available bone for safe implant placement, and allows the delineation of cortical and cancellous bone to attain maximum implant length and stability. Vital structures and the floor of the maxillary sinus are clearly shown. CONCLUSIONS: MRI allows the surgeon to assess cases for suitability to place dental implants with confidence. The ability to scan directly at any desired plane, with no reformatting, and to relate this information to a surgical template gives predictable surgery. MRI is a sectional imaging modality giving information about the 3-dimensional relationship of the vital structures, without using ionising radiation. It therefore deserves consideration as an alternative to computed tomography. However, further work is indicated to investigate the relative technical merits of the two imaging modalities.

Linking postdoctoral general dentistry programs with community-based clinical care settings.

This article presents the results of a small workgroup convened by the American Association of Dental Schools to examine experiences related to establishing and conducting dental education programs that have significant affiliations with community-based clinical care settings. The workgroup meeting is a component of the association's effort to identify and promote innovative and non-traditional methods by which the number of postdoctoral general dentistry (PGD) positions can be increased to meet current demand for PGD education. The participants identified factors and conditions believed to be critical to successful program linkages. The information should be helpful to others as they consider opportunities to establish PGD programs or increase their number of PGD training positions.

Pre-surgical dental implant assessment by magnetic resonance imaging.

The use of magnetic resonance imaging (MRI) for pre-surgical implant assessment of available bone in the maxilla and mandible is described. An acrylic surgical template with suitable MRI reference markers allows potential implant sites, as chosen on the MR images, to be accurately identified at surgery. MRI is a tomographic modality capable of giving accurate information on the three-dimensional relationships of all the relevant anatomic structures. Our results show that MRI is reasonably tolerant of artifacts caused by metal pins and amalgam fillings. Unlike computerized tomography (CT) and other x-radiographic techniques, MRI uses no ionizing radiation, and is capable of angulating and offsetting its scan plane at will. Good bone detail is available because cancellous bone yields a strong signal from the marrow fat, while cortical bone and dental enamel are dark. The excellent anatomic detail provided by thin-slice high-resolution MRI allows for assessment of the suitability of sites to receive an implant in terms of bone quality and thickness, and the relative position of the site to important structures such as the inferior dental nerve and nasal sinuses. The MRI technique used is described in detail. The principles underlying image contrast are outlined where appropriate and examples shown. To date, we have used MRI in conjunction with rotational panoramic x-rays (OPG) to plan 26 implants (21 maxillary, 5 mandibular) in 12 patients.

Issues in the dental care management of patients with bloodborne infectious diseases: an opinion survey of dental school seniors.

This study revealed some significant findings concerning the views of dental school seniors. Through a series of questions, we determined the opinions that seniors had about treating patients with bloodborne infections and the way they regarded their professional responsibility to provide care to these patients. We were able to identify that the majority of seniors had knowingly treated patients with one of these diseases, and believed that they had a professional obligation to do so. The study showed that these future professionals were aware of the risks related to disease transmission and they had real concerns about those risks; nevertheless, they were prepared to accept their professional obligation to provide care to these individuals. More than half of the survey population was fearful of treating patients with these diseases, and over half indicated that they would not treat these patients given the choice. This fear was compounded by their presumption that other patients would not want to be treated by a dentist who provides care to HBV/HIV patients, and by the presumption of increased cost of infection control. More than three fourths of these dental seniors agreed that treatment of infected patients would place them at higher risk. Nevertheless, in the face of this perceived danger, 62 percent indicated that they were willing to treat these patients, 79 percent said that they were capable of treating them, and 76 percent acknowledged the responsibility of the profession to treat. Another finding of note involves the treatment of infected patients and the effect that treatment experience had on the seniors' attitudes.(ABSTRACT TRUNCATED AT 250 WORDS)