Michael E. Fritz

The Use of Blade Implants in a Selected Population of Partially Edentulous Adults: A Five-Year Report

Based on the findings observed after the insertion of 33 blade implants in 23 patients, ages 31 to 74, for periods up to 60 months, the following conclusions can be made: (1) The blade implant is a technically feasible procedure which can be maintained in the mouth for period up to 5 years, although some degree of bony breakdown will be seen in a majority of the patients at this time; (2) The degree of breakdown around blade implants is almost exclusively located to the locus of the neck of the implant and is most likely due to the lack of attachment at the epithelial-implant interface.

Reversed Polarity in Transmembrane Potentials of Cells Infected with Herpesviruses

Summary Transmembrane potentials were recorded by electrophysiological techniques in HEp-2 tissue culture cells after infection with herpes simplex virus types 1 or 2, measles virus, Coxsackievirus B5, or adenovirus type 2, and in human fibroblast cells infected with herpes simplex virus type 1 or type 2 or with cytomegalovirus. Non-infected HEp-2 or fibroblast cells displayed negative polarity; whereas cells infected with types 1 or 2 herpes simplex viruses, cytomegalovirus, or measles virus displayed a shift to positive polarity. HEp-2 cells infected with Coxsackievirus B5 or adenovirus type 2 retained their internal negativity. These results suggest that further application of similar electrophysiological techniques might prove useful in the study of cell membrane changes induced by enveloped or oncogenic viruses. This investigation was supported in part by Grant 2879 from National Institute of Dental Research and by Grant T-521 from the American Cancer Society. We thank Antoinette Duffey and Julius Riggs for competent technical assistance and Drs. R. Rustigian, P. Feorino, W. Dowdle and J. Stewart for providing the measles, Coxsackie, adeno-and cytomegaloviruses used in these studies.

Two-stage implant systems.

Since the advent of osseointegration approximately 20 years ago, there has been a great deal of scientific data developed on two-stage integrated implant systems. Although these implants were originally designed primarily for fixed prostheses in the mandibular arch, they have been used in partially dentate patients, in patients needing overdentures, and in single-tooth restorations. In addition, this implant system has been placed in extraction sites, in bone-grafted areas, and in maxillary sinus elevations. Often, the documentation of these procedures has lagged. In addition, most of the reports use survival criteria to describe results, often providing overly optimistic data. It can be said that the literature describes a true adhesion of the epithelium to the implant similar to adhesion to teeth, that two-stage implants appear to have direct contact somewhere between 50% and 70% of the implant surface, that the microbial flora of the two-stage implant system closely resembles that of the natural tooth, and that the microbiology of periodontitis appears to be closely related to peri-implantitis. In evaluations of the data from implant placement in all of the above-noted situations by means of meta-analysis, it appears that there is a strong case that two-stage dental implants are successful, usually showing a confidence interval of over 90%. It also appears that the mandibular implants are more successful than maxillary implants. Studies also show that overdenture therapy is valid, and that single-tooth implants and implants placed in partially dentate mouths have a success rate that is quite good, although not quite as high as in the fully edentulous dentition. It would also appear that the potential causes of failure in the two-stage dental implant systems are periimplantitis, placement of implants in poor-quality bone, and improper loading of implants. There are now data addressing modifications of the implant surface to alter the percentage of osseointegration. New types of reinforcements for dental implants and the use of growth factors to augment bone regeneration so that implants can be placed more easily are now being actively investigated.

Idiopathic gingival fibromatosis with extensive osseous involvement in a 12-year-old boy.

Abstract Excessive gingival enlargement has been reported in the literature to be due to and/or accompanied by ingestion of Dilantin sodium, hypertrichosis, hereditary factors, cherubism, or ectodermal dysplasia; gingival enlargement has also been found where none of the above factors could be demonstrated, and this type of enlargement has been generally labeled “idiopathic.” The case reported here appears to be of special interest because of (1) the occurrence of both gingival enlargement and excessive osseous destruction in a very young person and (2) the absence of any marked medical deviation from normal, other than an elevated alkaline phosphatase activity. The latter finding, of course, may be related to the osseous destruction, as reports have implicated this enzyme in the process of bone resorption 5 or have suggested its presence as a sequel to bone resorption. 8

Demineralization of Bone by Phosphoprotein Phosphatase

Because of recent observations of the demineralization of enamel by phosphoprotein phosphatase, an experiment was designed to test this enzyme on bone. Decided destruction was evident in bone fragments that were incubated with phosphoprotein phosphatase buffered to pH 5.8 with 0.1 M acetate for periods of up to 15 hours.

HERPESVIRUSES AS INFECTIOUS AND ONCOGENIC AGENTS IN MAN AND OTHER VERTEBRATES

Publisher Summary This chapter discusses the role of herpesviruses as infectious and oncogenic agents in man and other vertebrates. There are at least five herpesviruses currently known to infect man: herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), varicella-zoster (V–Z) virus, cytomegalovirus (CMV), and Epstein–Barr (EB) virus. In addition, over 50 herpesviruses have been identified in more than 30 different species. Herpesviruses are characterized as particles measuring around 100 nanometers in diameter, having an icosahedral structure with 162 subunits or capsomeres and surrounded by an envelope that is derived from host cell membranes; the enveloped particles measure approximately 180 nanometers in diameter. The chapter describes the pathogenetic, immunological, and clinical features of herpetic infections, including their not uncommon association with cancer in man and other vertebrates.

Transmembrane Potential Changes in Cat Parotid Glands Infected with Feline Herpesvirus

A recent report from our laboratories has noted that various herpesviruses in tissue culture cells caused changes from internal negativity to internal positivity of the cells (FRITZ and NAHMIAS, Proc Soc Exp Biol Med 139: 1159-1161, 1972). The present study demonstrates that similar electrophysiologic changes could be established in an in vivo model of herpesviral infection in cat parotid glands. For comparative purposes, monolayers of feline kidney cells were inoculated with feline rhinotracheitis herpesvirus. When the cytopathic effect was also complete, the cells were removed mechanically and washed and pelleted in phosphate-buffered saline. Control uninfected cells, as well as the infected cells, were examined by conventional electrophysiologic methods. Results presented in the table demonstrate that, as with other herpesviruses studied in in vitro systems, feline herpesvirus caused a reversal of cell polarity. For the in vivo studies, 2 to 4-week-old kittens were inoculated with feline herpesvirus (0.1 ml of 106 PFU/ml) by retrograde ductal instillation into the parotid gland on one side. The contralateral gland was inoculated with tissue culture medium containing no virus. Electrophysiologic in situ recordings of the parotid cells (FRITZ, Am J Physiol 223: 644, 1972) were performed in virus-inoculated and control

Functional Innervation of Rabbit Salivary Gland

Summary Acinar cells of submaxillary gland of rabbit are not innervated by impulses passing through the superior cervical ganglion, as evidence by the lack of sympathetically induced secretory potentials and salivary flow. On the other hand, sympathetic impulses produced both salivation and secretory potentials in parotid gland of rabbit.

The Effect of Herpes Virus Infection on the Membrane Potential of Parotid Acinar Cells

Monolayers of feline parotid acinar cells were infected with feline rhinotracheitis herpes virus. Membrane potentials and input resistances were measured before and during infection. Uninfected acinar cells had an average membrane potential of -51 m V and resistances from 6 to 120 mega-ohms; cells infected for more than 18 h had an average membrane potential of -19 mV and resistances from 30 to 100 mega-ohms. The time course of the decrease in membrane potential was studied and was found to commence about ten to 14 h after infection.

Secretory Potentials in the Cat Parotid Gland in Response to Methacholine Chloride

Stimulation of parasympathetic secretomotor nerves or injection of acetylcholine in varying doses has produced acinar secretary potentials in the salivary glands of the cat (A. LUNDBERG, Acta Physiol Scand 35:1, 1955; 0. H. PETERSEN and J. H. POULSEN, Acta Physiol Scand 70:293, 1967; M. E. FRITZ and S. Y. BOTELHO, Am J Physiol 216:1392, 1969). Secretory potentials in response to parasympathomimetic stimulation are hyperpolarizing and range from 6 to 25 mv. The present study was designed to ascertain if the drug methacholine chloride acetyl-fB-methylcholine, (Mecholyl) in doses which produce a maximal salivary flow response (I. NORDENFELT and P. OHLIN, Acta Physiol Scand 41:12, 1957) produce secretary potentials of the same magnitude as supramaximal electric stimulation of the parasympathetic nerves. This drug, a choline ester that has been shown to have a more long-lasting effect on salivation than acetylcholine, then could be readily introduced into an artificial perfusate of salivary glands to study the origin of the secretary potential. Ten cats (2.1 to 3.4 kg each) anesthetized with pentobarbital sodium were used. Preparation of seven of the cats for close arterial injection was accomplished by isolating and ligating all branches of the external carotid artery except those going to the parotid gland (M. A. MIA and R. F. Sis, Arch Oral Biol 15:1, 1970). A cannula then was inserted into the external carotid artery so that the drug could be injected. Before ligation of the arteries, three secretary potentials were recorded in the parotid gland in response to supramaximal stimulation of the auriculotemporal nerve. At the termination of each experiment, an aqueous solution of fast green dye was perfused through the cannula to ascertain that the drug reached the gland. The measurement of transmembrane potentials has been described in other studies (M. E. FRrrz and S. Y. BOTELHO, Am J Physiol 216:1392, 1969 and M. E. FRITZ, Am J Physiol 220:1025, 1971). In this study, rest-