A superellipsoid-plane model for simulating foot-ground contact during human gait.

Musculoskeletal models and forward dynamics simulations of human movement often include foot-ground interactions, with the foot-ground contact forces often determined using a constitutive model that depends on material properties and contact kinematics. When using soft constraints to model the foot-ground interactions, the kinematics of the minimum distance between the foot and planar ground needs to be computed. Due to their geometric simplicity, a considerable number of studies have used point-plane elements to represent these interacting bodies, but few studies have provided comparisons between point contact elements and other geometrically based analytical solutions. The objective of this work was to develop a more general-purpose superellipsoid-plane contact model that can be used to determine the three-dimensional foot-ground contact forces. As an example application, the model was used in a forward dynamics simulation of human walking. Simulation results and execution times were compared with a point-like viscoelastic contact model. Both models produced realistic ground reaction forces and kinematics with similar computational efficiency. However, solving the equations of motion with the surface contact model was found to be more efficient (~18% faster), and on average numerically ~37% less stiff. The superellipsoid-plane elements are also more versatile than point-like elements in that they allow for volumetric contact during three-dimensional motions (e.g. rotating, rolling, and sliding). In addition, the superellipsoid-plane element is geometrically accurate and easily integrated within multibody simulation code. These advantages make the use of superellipsoid-plane contact models in musculoskeletal simulations an appealing alternative to point-like elements.

An international survey in postgraduate training in Oral Medicine.

OBJECTIVES: The aim of this preliminary study was to investigate postgraduate Oral Medicine training worldwide and to begin to identify minimum requirements and/or core content for an International Oral Medicine curriculum. MATERIALS AND METHODS: Countries where there was believed to be postgraduate training in Oral Medicine were identified by the working group. Standardized emails were sent inviting participants to complete an online survey regarding the scope of postgraduate training in Oral Medicine in their respective countries. RESULTS: We received 69 total responses from 37 countries. Of these, 22 countries self-identified as having postgraduate Oral Medicine as a distinct field of study, and they served as the study group. While there is currently considerable variation among Oral Medicine postgraduate training parameters, there is considerable congruency in clinical content of the Oral Medicine syllabi. For example, all of the training programs responded that they did evaluate competence in diagnosis and management of oral mucosal disease. CONCLUSIONS: This preliminary study provides the first evidence regarding international Oral Medicine postgraduate training, from which recommendations for an international core curriculum could be initiated. It is through such an initiative that a universal clinical core syllabus in postgraduate Oral Medicine training may be more feasible.

Dental management considerations for the patient with diabetes mellitus.

BACKGROUND: The prevalence of diabetes mellitus, or DM, in the United States is increasing steadily. The increasing longevity of the American population and more effective diagnostic protocols mean that the dental practitioner will be treating an increasing number of patients with the disease. METHODS: The authors present relevant information about DM, including a recently revised nomenclature system, pathophysiology, complications, new diagnostic criteria, medical and dental management considerations, and associated oral conditions. CONCLUSIONS: There are many important medical and dental management issues that dentists should consider when treating patients with DM. CLINICAL IMPLICATIONS: The information presented in this report should help general dentists deliver optimum treatment to patients with DM.

Peroral famciclovir in the treatment of experimental ultraviolet radiation-induced herpes simplex labialis: A double-blind, dose-ranging, placebo-controlled, multicenter trial.

Three doses of famciclovir were tested for treatment of experimental ultraviolet radiation (UVR)-induced herpes labialis. Patients received 125, 250, or 500 mg of famciclovir or placebo 3 times a day for 5 days beginning 48 h after UVR exposure, a model of early episodic intervention. Of 248 patients irradiated, 102 developed lesions while on treatment. There were no significant differences between groups in the number of lesions. The mean maximal lesion size was reduced in a dose-proportional manner: 139, 105, 77, and 55 mm2 for the placebo and 125-, 250-, and 500-mg famciclovir groups, respectively (P=.040, linear regression). Median time to healing was faster in the 500-mg famciclovir group than in the placebo group, both by investigator (4 vs. 6 days, 33% reduction, P=.010) and patient assessment (3.0 vs. 5.8 days, 48% reduction, P=.008) analyses. These findings suggest that evaluation of higher drug doses for herpes labialis treatment is warranted.

Measurement of lip and skin pigmentation using reflectance spectrophotometry.

Previous methods for evaluating the color of oral epithelial tissues have relied primarily on subjective indices and interpretation. In this study, a narrow-band reflectance spectrophotometer was used to measure melanin and hemoglobin pigmentation in the lips and skin of individuals who self-reported their skin type from a choice of white, olive, or black. Significant differences in melanin pigmentation were observed among skin types and at most anatomical sites evaluated between skin types. Hemoglobin levels were not significantly different among skin types at most anatomical sites, but differences were observed among anatomical sites within each skin color group. Within each skin type, melanin (except in blacks) and hemoglobin were significantly higher for both the upper and lower lips compared with most other anatomical sites. Results suggest that reflectance spectrophotometry is a useful tool for quantifying differences in melanin and hemoglobin pigmentation in oral tissues.

Oral verruca vulgaris in a bone marrow transplant patient: a case report and review of literature.

Viral infections can cause severe morbidity in immunosuppressed cancer patients. A case of rapidly enlarging, biopsy-documented oral verruca vulgaris in a patient undergoing conditioning chemotherapy prior to bone marrow transplantation (BMT) is described. Human papillomavirus infections in immunosuppressed patients are discussed.

Helium-neon laser effects on conditioning-induced oral mucositis in bone marrow transplantation patients.

BACKGROUND: Oral mucositis is a common complication of bone marrow transplantation (BMT) conditioning therapy. Sequelae consist of increased risk for infection, moderate to severe pain, compromised oral function, and bleeding. This study investigated helium-neon laser treatment for prevention of conditioning-induced oral mucositis in BMT patients. Patterns and severity of mucositis for specific conditioning drug regimens also were analyzed. METHODS: Twenty patients received laser radiation to their oral mucosa, either left or right of midline. The contralateral side was sham-treated and served as a control. Mucositis severity was scored independently by two modified versions of the Oral Mucositis Index Scale (OMI-A and OMI-B) and the Eastern Cooperative Oncology Group (ECOG) Oral Toxicity Scale; pain severity was scored by subjects on a visual analogue scale (VAS). Cumulative scores were analyzed for differences between the laser-treated and sham-treated sides. RESULTS: Oral mucositis and pain scores were significantly lower for the treated versus the untreated side by OMI-A and B (P < 0.005) and VAS (P = 0.027) criteria, respectively. Ulcerative lesions occurred in all patients bilaterally; severity increased until Day +6, and lesions resolved by Day +21. Mucositis was more severe for patients conditioned with busulfan/carboplatin/thiotepa than for patients conditioned with busulfan/cyclophosphamide/etoposide. CONCLUSIONS: Helium-neon laser treatment was well-tolerated and reduced the severity of conditioning-induced oral mucositis in BMT patients.

Visualizing taste papillae in vivo with scanning electron microscopy of a high resolution cast.

A method using polyvinylsiloxane (PVS), a high-resolution dental impression material, to obtain negative images of lingual surfaces is described. Epoxy-resin tongue replicas made from these impressions were examined with scanning electron microscopy (SEM). This method has been developed to visualize structural details of the tongue surface of living human beings and laboratory animals. The utility of the method is demonstrated with hamster tongues, which have well-defined fungiform papillae with single taste pores, and human tongues, which have more variable surface structures. Replicas made from PVS impressions of tongues of living hamsters were compared with the same tongues after fixation. The replicas contained much of the detail present in fixed tongues. With SEM, it was possible to identify individual fungiform papillae, which contained depressions with the size and the location of hamster taste pores. Individual papillae could also be recognized in human-tongue replicas, but taste pores could not be identified with certainty. These replicas provide permanent, three-dimensional records of tongue topography that could be used to document changes due to trauma, disease and aging.

Nonsurgical management of head and neck cancer patients.

This article has reviewed selected oral complications that can develop in the head and neck cancer radiation patient. Many of these complications can be prevented by treating diseased oral sites before initiation of cancer therapy. In addition, cancer treatment can often cause changes in oral tissues that require long-term management. The dentist can thus play an important role in the overall care of these critically ill patients.

Postextraction osteomyelitis in a bone marrow transplant recipient.

This report describes a case of mandibular osteomyelitis after a dental extraction in a patient who subsequently underwent bone marrow transplantation (BMT) for lymphoblastic lymphoma. Surgical guidelines consistent with National Cancer Institute recommendations were followed for the extraction, which was performed before initiation of the myelosuppressive conditioning regimen. However, moderate tenderness developed at the extraction site beginning 10 days after marrow infusion. On day 26 the patient became febrile and blood culture-positive for Staphylococcus epidermidis. Radiographs exposed on day 28 demonstrated changes consistent with low-grade osteomyelitis, including diffuse loss of lamina dura and an irregular osseous rarefaction extending 1 cm posterior to the extraction site. Although the indwelling Hickman catheter was the presumed source for bacteremia, clinical and radiographic data led to consideration of mandibular osteomyelitis as an alternative cause. Characteristics of this infection in BMT recipients are reviewed. Recommendations for dental extractions and prophylactic antibiotic regimens for catheterized BMT recipients are also discussed. Although mandibular osteomyelitic lesions are not common in profoundly immunosuppressed BMT recipients, prompt recognition and treatment are essential when the disease occurs.

Diagnostic considerations for the medically complex patient.

As advances in medical diagnostic and treatment modalities continue to increase the life expectancy of the population, the likelihood of encountering patients in dental practice with concomitant medical problems will also rise. Thus it will become increasingly important for practicing dentists to take thorough medical histories, recognize signs of systemic disorders, and work closely with their medical colleagues to ensure that safe dental care is rendered to these medically complex patients. Although acutely ill or severely compromised individuals may be best treated in a hospital setting by those with special training, all dental practitioners should possess the diagnostic and communicative skills needed to manage those who are receiving out-patient medical care.

Diagnosis and management of acute and chronic oral complications of nonsurgical cancer therapies.

This article has reviewed selected oral complications that can develop in the myelosuppressed or head and neck radiation cancer patient. Many of these complications can be prevented by treating diseased oral sites prior to initiation of cancer therapy. Further, cancer treatment often causes changes in oral tissues that require long-term management. The dentist thus can play an important role in the overall care of many cancer patients.

Jaw and skull changes in neurofibromatosis.

Thirty-eight patients with neurofibromatosis were examined clinically and radiographically for manifestations of the disease in the head and neck region. Ninety-two percent of the sample had at least one intraoral or radiographic sign of the disease. This suggests that the incidence of jaw and skull involvement in neurofibromatosis may be greater than previously reported in the literature.

Diagnostic quality versus patient exposure with five panoramic screen-film combinations.

Five film-screen combinations were used to make five density-matched panoramic radiographs of a tissue-equivalent phantom skull using the Midwest/Morita Panoral x-ray machine. The radiographs were evaluated as to their diagnostic quality by twenty dental radiologists. The results demonstrate that proper screen-film selection can significantly reduce patient exposure without compromising diagnostic quality.

The effect of betamethasone dipropionate injectable on chronic bronchial asthma.

Betamethasone dipropionate was administered intramuscularly to fifty-one patients with chronic bronchial asthma. Good to excellent results were obtained in 96% of patients. Onset of action was rapid, and duration of action was prolonged. Adverse reactions were mild and transient. Decreases in early morning plasma cortisol levels were also transient with the levels returning to normal range by the end of the study in all but one patient.