Ancient schwannoma of the submandibular gland: a case report.

Schwannomas (neurilemmomas) are neurogenic tumors that arise from the Schwann cells of the neural sheath. They are most often benign and solitary. Extracranial schwannomas are rare, and can be mistaken for metastatic disease or other non-neurogenic tumors. Ancient schwannoma is a rare variant of schwannoma with a course typical of a slow-growing benign tumor. Histologically, it can be confused with a malignant mesenchymal tumor. An unusual case of an ancient schwannoma of the submandibular gland is reported. The clinical, histological and surgical aspects of this tumor are discussed, and the literature regarding this rare entity is reviewed.

Orthotopic laryngeal transplantation: is it time?

The notion of returning phonatory and respiratory function by transplanting larynges has fascinated and challenged the minds of laryngologists for many years. In the past, the problems of revascularization, tissue rejection, and physiologic vocal fold motion have stymied the success of research in this area. Today, advances in microvascular surgery, graft versus host response, and selective reinnervation have made laryngeal transplantation a theoretical, if not a practical reality. Despite this progress, serious ethical and fiscal considerations remain unresolved. This report will discuss these advances as well as concerns and will present the current UCLA laryngeal physiology laboratory experience with canine laryngeal transplantation.

Preoperative evaluation for partial laryngectomy.

The object of this study was to determine if pulmonary function tests were necessary in the preoperative evaluation of potential candidates for conservation laryngeal procedures. In addition, pulmonary complications from a series of partial laryngectomies were examined and correlated with a previous history of chronic obstructive lung disease. Ninety-four patients with laryngeal tumors amenable to a partial procedure were assessed preoperatively by testing their pulmonary function by stair-climbing; they were considered to possess enough pulmonary function to permit a partial procedure. Pulmonary function tests were obtained in 69 of these patients. Measurements of vital capacity and forced expiratory volume in 1-second were reviewed and correlated with the postoperative development of pulmonary complications to determine if these tests of pulmonary function could reliably predict which patients would be more prone to developing pulmonary complications. The results indicated that pulmonary function tests or a prior history of chronic obstructive pulmonary disease (COPD) could not reliably predict postoperative complications.

Surgical treatment of iatrogenic canal blockages.

The endodontist of today is confronted with managing retreatment failures. Some of these can involve the retreatment of intracanal blockages. Many times, conventional endodontics cannot be redone, so a surgical approach may be needed. This article reviews four basic surgical techniques that can be used for retreatment of intracanal blockages. When the blockage cannot be removed, a standard retrograde amalgam technique or the Nygaard Ostby procedure of reverse instrumentation-obturation can be used. Two other surgical techniques used to eliminate the blockage are the apical loosening technique and a true apicoectomy procedure. Each of these procedures is reviewed, and the advantages and disadvantages are discussed.

Paste technique re-treatment study: a clinical, histopathologic, and radiographic evaluation of 50 cases.

This study correlated clinical, radiographic, and histopathologic aspects of 50 endodontic failures involving the paste technique. All clinical and radiographic findings were recorded. The teeth were re-treated with gutta-percha/Kloroperka and lateral condensation. Subsequently, periapical surgery, including retrograde amalgam filling, was performed for the removal of material in the periapical tissue. The resulting biopsy specimens were processed for histologic evaluation. Although neutrophilic leukocytes predominated in some cases, all types of inflammatory cells were present. Macrophages and foreign body cells contained paste particles. The blood pigment distinguished hemorrhage due to surgery from pathologic circulatory changes. There was resorption/apposition of bone and root fragments. Epithelial strands and parts of cyst walls were observed. There was a correlation between a periapical radiolucency and inflammation but no correlation between amounts and types of inflammatory cells and pain. Paste placed beyond the foramen caused tissue damage and reduced prognosis.

Cell-mediated immune response to dog pulp tissue altered by Proco-Sol via the root canal.

Pulp tissue from three experimental dogs was tested for its antigenicity before and after incubation with Proco-Sol sealer (PS). Cell-mediated skin test reactions showed an increased response to pulp that had been incubated in Proco-Sol, washed, and then injected, as compared with pulp or PS alone. In vitro analysis of cell-mediated immune response (lymphocyte proliferation) showed a marked increase when pulp tissue was incubated in PS and washed, as compared to saline-treated pulp. Comparison of the saline-incubated pulp to the PS-altered pulp indicated that the increase in radioactivity was statistically significant at p less than 0.0001. Thus, Proco-Sol sealer altered dog pulp tissue and rendered it antigenically active, and a specific cell-mediated lymphocyte response was produced.

Antibody formation to dog pulp tissue altered by camphor paramonochlorophenol via the root canal.

Pulp tissue from three experimental dogs was tested for its antigenicity before and after incubation with CMCP. Reaction to Arthus skin tests showed an increased response to pulp that had been incubated in CMCP, washed, then injected, as compared with pulp or CMCP alone. Hemagglutinating antibody titers (1:360 to 1:450 dilutions) were obtained from pulp tissue altered by CMCP. Inhibition tests showed the specificity of the antibody to be at a dilution titer of 1:350. Therefore, CMCP altered dog pulp tissue and rendered it antigenically active, and a specific humoral response was produced.

Systemic distribution of N2 paste containing 14C paraformaldehyde following root canal therapy in dogs.

Using rubber-dam isolation and an aseptic and standardized endodontic technique, root canal therapy was performed on the right and left fourth mandibular premolars in four dogs. Each tooth was obturated with N2 paste containing 6.5 percent 14C paraformaldehyde. In each dog at 1 hour, 1, 7, 14, and 28 days, blood was drawn and biopsy specimens were taken of the adjacent lymph nodes, liver, and kidney. At 28 days, the animals were killed, and the experimental and adjacent tissues were processes for light microscopy. Histologic examination demonstrated that particles of the paste placed in the root canal were present in pulp, periapical, and periodontal tissues remote from the original site in the root canal. In addition, 14C-labeled paraformaldehyde which was contained in the N2 paste was found in blood, regional lymph nodes, kidney, and liver. The amount of radioactivity in all the body organs decreased with time.

Antibody formation to dog pulp tissue altered by AH-26 sealer via the root canal.

Pulp tissue from three experimental dogs was tested for its antigenicity before and after incubation with AH-26 sealer. identical to Reactions to Arthus skin tests showed an increased response to pulp that had been incubated in AH-26, washed, and then injected, as compared with the material alone. Hemagglutinating antibody titers (1/500 to 1/800) were obtained from pulp tissue altered by AH-26. Inhibition tests showed the apecificity of the antibody to be at a dilution titer of 1:400. Therefore, a mixture of AH-26 sealer altered dog pulp tissue and rendered it antigenically active, and a specific humoral response was produced.

Cell-mediated immune response to dog pulp tissue altered by Grossman's formula sealer via the root canal.

Pulp tissue from three experimental dogs was tested for its antigenicity before and after incubation with Grossman's formula sealer (GS). Cellmediated skin-test reactions showed an increased response to pulp that had been incubated in Grossman's formula sealer, washed, and then injected as compared with pulp or GS alone. In vitro analysis of cell-mediated immune response (lymphocyte proliferation) showed a marked increase when pulp tissue was incubated in GS and washed as compared to saline-treated pulp. Comparing the saline-incubated pulp to the GS-altered pulp revealed that the increase in radioactivity was statistically significant at p less than 0.0001. Therefore, Grossman's formula sealer altered dog pulp tissue and rendered it antigenically active, and a specific cell-mediated lymphocyte response was produced.

Antibody formation to dog pulp tissue altered by Grossman's Formula Sealer via the root canal.

Pulp tissue from experimental dogs was tested for its antigenicity before and after incubation with Grossman's Formula Sealer (GS). Reactions to Arthus skin tests showed an increased response to pulp that had been incubated in GS, washed, and then injected, as compared with the material alone. Hemagglutinating antibody titers (1:160 to 1:360) were obtained from pulp tissue altered by GS. Inhibition tests showed the specificity of the antibody to be at a dilution titer of 1:200. Therefore, GS altered dog pulp tissue and rendered it antigenically active, and a specific humoral response was produced.

Antibody formation to dog pulp tissue altered by Kerr (Rickert's) sealer via the root canal.

Pulp tissue from three experimental dogs was tested for its antigenicity before and after incubation with Kerr (Rickert's) sealer (KS). Reactions to Arthus skin tests showed an increased response to pulp that had been incubated in KS, washed, and then injected, as compared with the material alone. Hemagglutinating antibody titers (1/360--1/600) were obtained from pulp tissue altered by KS. Inhibition tests showed the specificity of the antibody to be at a dilution of titer of 1:300. Therefore, a mixture of Kerr (Rickert's) sealer altered dog pulp tissue and rendered it antigenically active, and a specific humoral response was produced.