Electron transfer via redox hydrogels between electrodes and enzymes.

The molecular "wiring" of redox enzymes provides the basis for amperometric enzyme and affinity sensors. The key features of the useful redox polymers are hydrophilicity and flexibility.

Congenital ankylosis of the temporomandibular joint: resultant upper airway obstruction and cor pulmonale.

Cor pulmonale and severe congestive heart failure secondary to chronic upper airway obstruction developed in a three-year-old girl with congenital ankylosis of the temporomandibular joint complicated by frequent respiratory infections. Nearly absent mouth opening, micrognathia, and mandibular retroposition with resultant glossoptosia obstructed the airway. Medical treatment followed by a tracheostomy and bilateral condylectomy relieved the obstruction allowing normal function of the temporomandibular joint. The clinical, electrocardiographic, radiologic, and hemodynamic findings returned to normal. Congenital ankylosis of the temporomandibular joint has not been previously reported as a cause of cor pulmonale secondary to upper airway obstruction.

Biocompatible, glucose-permeable hydrogel for in situ coating of implantable biosensors.

A glucose-permeable hydrogel (97% water by mass) was formed by cross-linking an 8-armed, amine-terminated poly(ethylene glycol) (PEG) derivative with a di-succinimidyl ester of an alpha,omega-dipropionic acid derivative of PEG in aqueous solution at room temperature. The gel was evaluated as a biocompatible interface between an amperometric glucose electrode and the subcutaneous tissue of a rat. Over a glucose concentration range of 0-30 mM, the loss in sensitivity to glucose caused by the application of the hydrogel was 34% and the reduction in limiting current at high glucose concentration (30 mM) was 35% at 37 degrees C for films that were approximately 0.06 mm thick, an acceptable loss. Hydrogel and Pellethane samples were subcutaneously implanted in male Sprague-Dawley rats for 7 days. The explanted samples were thin-sectioned, stained and examined under a light microscope. While the Pellethane samples were encapsulated with tissue consisting of macrophages, neutrophils, foreign body giant cells, fibroblasts and collagen, the PEG samples had very few adherent cells. The results show this system to be a good candidate for providing biocompatible interfaces for sensors, especially oxidoreductase-based sensors.

Photo-crosslinked copolymers of 2-hydroxyethyl methacrylate, poly(ethylene glycol) tetra-acrylate and ethylene dimethacrylate for improving biocompatibility of biosensors.

A copolymer containing 88% 2-hydroxyethyl methacrylate (HEMA), 9% poly(ethylene glycol) (MW 18.5 kDa) tetra-acrylate and 3% ethylene dimethacrylate was prepared and evaluated for use as a biocompatible interface between glucose biosensors and tissue in the rat. The glucose sensor utilizes glucose oxidase that is electrically 'wired' to a gold current collector by a reduction-oxidation polymer. Coatings of the copolymer were crosslinked in situ on the sensors using long wavelength ultraviolet light and 2,2-dimethoxy-2-phenyl-acetophenone as the initiator. The effect these films had on the current response to glucose was measured. Over a glucose concentration range of 0-30 mM, the average percentage decrease in response was 45 +/- 28% (mean +/- 95% confidence interval) at 37 degrees C for films that were about 0.1 mm thick, an acceptable value. Copolymer-treated and control electrodes were implanted in the intrascapular subcutaneous tissue of male Sprague-Dawley rats for three days. The explanted samples were evaluated using scanning electron microscopy. The control electrodes were highly encapsulated with fibrous material, while the copolymer-treated electrodes induced much less encapsulation. The results show this copolymer to be a candidate as a biocompatible coating for electrically wired oxidoreductase-based subcutaneous biosensors.

Stereotaxic electrode placement in the neonatal rat.

A head holder for stereotaxic electrode placement in the neonatal rat is described. The neonatal head is held in a fixed and reproducible position by means of a mouth bar and a recurved needle hooked into the foramen magnum. With the aid of this instrument, a stereotaxic atlas for the 3-day-old rat has been prepared. The head holder has been used for rats up to 10 days of age and permits electrode placement in the neonatal rat in a manner essentially analogous in ease and precision to that of stereotaxic methods for the adult animal.

Amperometric biosensor for in vivo glucose sensing based on glucose oxidase immobilized in a redox hydrogel.

A potentially implantable glucose sensor, based on glucose oxidase immobilized in a redox hydrogel, is considered. The redox hydrogel consisted of glucose oxidase immobilized in a cross-linkable poly(vinylpyridine) complex of [Os(bis-bipyridine)2Cl]+1/+2 that communicates electrically with the flavin adenine dinucleotide (FADH2) redox centres of the glucose oxidase. The implantable electrode consisted of a Teflon insulated platinum wire (0.25 mm diameter) which was coated at the tip with a cross-linked redox polymer/glucose oxidase film and covered with a thin layer of polycarbonate. In a three-electrode system at +400 mV (Ag/AgCl) the response to increasing glucose concentrations in isotonic phosphate buffer and human plasma was approximately 0.2-0.3 nA/mM, linear in the range between 0 and 15 mM glucose. No oxygen dependence was observed. To determine the in vivo performance, the electrode was implanted into the subcutaneous tissue of a dog. The sensor currents after an oral glucose load paralleled the plasma glucose measurements, with a time lag of 10 min. Three-day implantations in cultured cells showed that the electrode did not affect the growth and differentiation of cell monolayers.

Squamous cell carcinoma of the gingiva presenting as an endoperiodontic lesion.

An unusual case of gingival carcinoma, initially presenting as an endoperiodontic lesion without clinical evidence of malignancy, is presented. It is important to consider carcinoma of the gingiva in cases of an endoperiodontic lesion unresponsive to therapy, and to investigate further when bone resorption occurs around one tooth. Submission of all dental tissue removed during oral surgical procedures for pathologic analysis may be beneficial.

Cystinosis and gingival hyperplasia: demonstration of cystine crystals in gingival tissue and unusual aspects of management.

A patient with nephropathic cystinosis developed gingival hyperplasia secondary to cyclosporine-A therapy for his renal allograft. The typical crystals described on electron microscopic examination of other organs of patients with cystinosis were seen in the resected gingiva of this patient. These crystals have not been previously described in this location. Unusual aspects of the management of this patient are discussed.

Ewing's sarcoma of the mandible: a case report.

Ewing's sarcoma is an uncommon malignancy that usually occurs in childhood and is rare in the mandible. A case of Ewing's sarcoma of the mandible is presented and discussed.

The psychosocial functioning of young adults born with cleft lip or palate. A follow-up study.

A follow-up study of 96 young adults born with a cleft lip and/or cleft palate was conducted to determine their present psychosocial adjustment and to evaluate the services offered to them. Medical histories were obtained from hospital charts. Telephone interviews focusing on educational achievement, work performance, and social integration showed that 10 to 33%, depending on the criteria used, experienced psychosocial maladjustment, There was a high rate of persistent dissatisfaction with appearance, hearing, speech, teeth, and social life. An analysis of the services offered to these young adults, in the light that counseling or other social support might be offered routinely during childhood and, of equal importance, during adolescence when further medical, surgical, and dental treatment may also be required.

Clinical evaluations of a porous-surfaced endosseous implant system.

Clinical evaluations of a new porous-surfaced implant concept (Endopore) in a large population of fully and partially edentulous patients are reported, and a technique of spreading buccal and lingual plates with osteotomes to place these implants in proximity to the sinus of the posterior maxilla is described. Three-dimensional, interconnecting pores on this implant's bone interface surface give a great surface area for bone engagement. When the maxilla is prepared by this spreading procedure, these implants can be successfully placed in areas having limited available bone. Our success rates are 97.0% for implants stabilizing a mandibular overdenture and 94.8% for implants placed in partially edentulous patients. Many times, sinus lift or other augmentation procedures can be avoided in the maxilla and mandible, allowing for less patient morbidity and for an implant reconstruction that is more affordable for the patient.

Alternative to the inferior alveolar nerve block anesthesia when placing mandibular dental implants posterior to the mental foramen.

Local anesthesia block of the inferior alveolar nerve is routinely taught throughout dental education. This commonly used technique eliminates all somatosensory perception of the mandible, mandibular teeth, floor of the mouth, ipsilateral tongue, and all but the lateral (buccal) gingivae. Generally, the dentist or surgeon desires these structures to be anesthetized. However, in the placement of mandibular implants, it may be useful for the patient to be able to sense when the inferior alveolar nerve is in danger of being damaged, possibly producing permanent paresthesia. In this article, the technique of mandibular infiltration prior to mandibular implant placement in the mandible is discussed.

Soft tissue management techniques for implant dentistry: a clinical guide.

Establishing nontension primary closure over implant and bone-grafted sites begins with proper soft tissue management. This paper will demonstrate the various soft tissue flap designs required to optimize postsurgical wound healing. Simple and advanced flap management techniques are described in a step-by-step manner utilizing drawings to show each step-by-step surgical procedure. Management of postoperative soft tissue complications will also be addressed.

Squamous cell carcinoma of the gingiva. A review.

The main predictor of survival is clinical stage at diagnosis. If diagnosed early enough, squamous cell carcinoma of the gingiva is curable. It is important that dentists be aware of the early signs of disease. They are often the first professional seen by these patients, and are the most skilled among health care workers at performing oral examinations.

Treatment of gingival Crohn's disease with laser therapy.

Crohn's disease is an inflammatory disease of unknown etiology. Oral manifestations appear most frequently on the lips, gingival tissue and buccal mucosa. The case presented here shows how a patient with oral lesions resulting from Crohn's disease can be treated by laser therapy and obtain optimal esthetic results.