The reaction of skin to primers used in the "single-step" bonding systems

A large number of direct bonding systems have been introduced for use by dentists and dental hygienists. Although these agents are used for direct bonding of brackets to enamel, contact with skin, oral mucosa, and gingiva is not uncommon. These products have wide clinical use, but their biocompatibility characteristics have not been extensively investigated. The present study was undertaken to determine the effects of the primer component of Mono-Lok (Rocky Mountain) and the primer component of Control (Lancer Pacific) on skin. Three adult Macaca mulatta monkeys were used in the study. The skin on their backs was shaved and the primer component of Control, primer component of Mono-Lok, and saline solution were applied at different sites every 3 days for up to four applications. The skin was examined clinically and, 5 days after the last application, a biopsy was performed for histologic evaluation. The skin in contact with the primer component of Mono-Lok exhibited pronounced inflammatory changes and was characterized by swelling, vesiculation, and ulceration. Histologic observations confirmed these findings by showing a marked inflammatory cellular response characterized by eosinophils. In contrast to these findings, the skin in contact with the primer component of Control or saline solution exhibited normal architecture. Histologic observations supported this appearance and showed minimal inflammatory cell infiltration. These results show that there are differences in the biocompatibility of direct bonding systems and that further studies are needed to clarify their long-term effects on patients and dental personnel.

Initial attachment of fibroblast-like cells to periodontally-diseased root surfaces in vitro

The precise factors mediating both initial cell attachment and longer term connective tissue reattachment after tissue destruction due to periodontal disease are not known. An in vitro model was used to assess initial attachment of fibroblast-like cells to periodontally-diseased root surfaces. Root fragments were obtained from freshly extracted teeth from 6 different patients. Individual roots were prepared such that a comparison could be made of initial attachment to non-instrumented diseased root surface, curetted diseased root surface and the non-diseased, non-instrumented portion of the same root. The amount of hard tissue removed by instrumentation was quantitated and kept constant between 0.9-1.0 mm. The unsterilized fragments were incubated with human gingival fibroblasts (HGF) for 1 h at 37 degrees, after which the roots were first washed to remove non-adherent cells and then photographed. The number of attached cells per unit area was quantitated from the photographs using a grid system. No significant differences could be detected between the numbers of cells attached to the 3 types of root surfaces studied on the individual roots or between any of the roots studied. Thus, initial attachment of HGF to diseased root surfaces is not inhibited by the presence of plaque or endotoxins.

Tissue reaction to primers used in the "single-step" bonding system

A large number of direct-bonding systems have been introduced for use by orthodontists. Although these agents are used for direct bonding of brackets to enamel, contact with skin, oral mucosa, and gingiva is not uncommon. While these products have wide clinical use, their biocompatibility has not been extensively investigated. The present study was undertaken to determine the effects of the primer component of Mono-Lok and the primer component of Control on gingiva. Three adult and one juvenile Macaca mulatta monkeys were used in this investigation. In two adults and the one juvenile animal, the primer component of Mono-Lok was applied to the right buccal surfaces of teeth; in the remaining adult animal, the primer component of Control was applied to the right buccal surfaces of teeth. The excess material was extended 5.0 mm onto the gingival tissues and for 3 minutes the cheeks and saliva were kept away from the sites to be tested. Saline solution was applied to the left buccal segments in all animals. Primer and saline solution were applied at 3-day intervals for a period of 21 days. The gingival tissues were examined clinically and biopsied for histologic evaluation. The gingiva in contact with the primer component of Mono-Lok exhibited pronounced inflammatory changes and was characterized by redness, swelling, and spontaneous bleeding. Histologic observations confirmed these findings by showing a marked inflammatory cellular response characterized by eosinophils. In contrast to these findings, the gingiva that was in contact with the primer component of Control or saline solution exhibited normal gingival architecture.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of maternal attitudes on urban, black teens' decisions about abortion v delivery

Two hundred thirty-one inner city black teenagers, aged 14-17, were followed for two years to assess whether (1) their decision to deliver or abort a pregnancy differed from their perceptions of their mothers' attitudes about having a child or aborting a pregnancy, (2) satisfaction with the decision differed between the abortion and delivery groups, and (3) satisfaction with the decision was affected by who made the decision. Eight-one percent chose the pregnancy outcome that their mothers supported. Those who did decide without their mothers' support (19%) were divided equally between abortion and continuing the pregnancy. The majority in both groups were satisfied with the outcome decision, but initially more deliverers than aborters were satisfied. Satisfaction initially was related to who made the decision, but by the one-year follow-up the difference was no longer significant. Young teens do not seem likely to make a decision about pregnancy outcome that differs from their mothers' views; initial differences in satisfaction with the decision disappear over a one- to two-year period.

Effects of gold salts on experimental periodontitis. III. Ultrastructural observations

Previous studies showed that the systemic administration of soluble gold salts resulted in significantly less periodontal destruction after 2 weeks of experimentally induced periodontitis. The present study compared the ultrastructural characteristics of the inflammatory lesion in animals receiving gold salts (experimental) with those in animals that had not received gold salts (control). Maxillary gingival biopsy specimens were obtained from the buccal aspect of ligatured teeth after 2 weeks of experimental periodontitis. A cellular and extracellular ultrastructural characterization was done in an "epithelial and superficial connective-tissue zone," and a "deep connective-tissue zone." Experimental (gold-receiving) specimens had an intact sulcular epithelium with narrow intercellular spaces overlying a collagen dense connective tissue. Control specimens had a degenerating disrupted epithelium overlying a collagen-poor connective tissue in which polymorphonuclear leucocytes predominated and often were closely apposed to morphologically altered fibroblasts. The cellular distribution of electron-dense deposits of gold salts was demonstrated, and their possible role in modulating mechanisms of cell cytotoxicity and collagen turnover is discussed.

Effects of gold salts on experimental periodontitis. I. Histometric evaluation of periodontal destruction

Systemic administration of gold salts for treatment of arthritis is thought to limit tissue destruction through alteration of inflammatory cell function. The present study ascertained if gold salts could modify the tissue destruction associated with an experimental marginal periodontitis. Therapeutic levels of serum gold salts were established in four squirrel monkeys (experimental) by intramuscular injection of Myochrisine (gold sodium thiomalate 25 mg/ml) at 5 mg/kg/body weight at 4-day intervals for 12 days. Marginal periodontitis was then induced around mandibular bicuspids by tying plaque retentive ligatures at the gingival margins. Periodontitis was induced around corresponding teeth in four control animals which had not received gold salts. Serum levels of gold salts were maintained in experimental animals, and all animals were killed 2 weeks after induction of periodontitis. Progression of periodontitis was evaluated histometrically on step-serial sections, and the results analyzed statistically. Specimens from gold-receiving animals had significantly smaller areas of infiltrated supracrestal connective tissue, and less loss of connective tissue attachment and coronal alveolar bone. Quantitation of total plaque around the ligatures showed no differences; however, there was less plaque located apical to the ligatures in gold-receiving specimens. Although the study design did not permit identification of the relative importance of cellular or microbial factors, it was concluded that administration of systemic gold salts was associated with significantly less periodontal destruction.

Effects of gold salts on experimental periodontitis. II. Cell population characteristics

A previous study showed that the systemic administration of soluble gold salts (gold sodium thiomalate) resulted in significantly less periodontal destruction after 2 weeks of experimentally induced periodontitis. In order to provide information on the possible mechanisms of action of gold salts in the experimental periodontitis situation, the present study analyzed and compared the characteristics of the inflammatory cell populations in animals receiving gold salts with those present in animals which had not received gold salts. Maxillary gingival biopsy specimens were obtained from the buccal aspect of ligatured teeth after 2 weeks of experimental periodontitis. Cell populations were characterized and enumerated, on 1-micron sections, in an epithelial and superficial connective tissue zone, and a deep connective tissue zone. Significantly fewer inflammatory cells were present in experimental (gold receiving) specimens, and this reduction was due primarily to fewer polymorphonuclear leucocytes (PMNs). No significant reduction occurred in any other inflammatory cell-type. The reduction in number of PMNs in experimental specimens was associated with a decreased number of morphologically altered, degenerating fibroblasts in the connective tissue compared to the PMN-dominated lesion of control specimens. Mechanisms whereby gold salts can reduce chemotaxis and functional capabilities of inflammatory cells are discussed.

A periodontal attachment mechanism without alveolar bone. Case report

A 22-year-old black male was referred for periodontal therapy because of radiographic evidence of advanced bone loss associated with the posterior teeth. Clinical examination revealed gingivitis, normal sulcus depths, and minimal loss of clinical attachment. Complete blood counts, serum chemistry, and neutrophil function were within normal limits. Histological, histochemical and ultrastructural analysis of an extracted tooth revealed no loss of attachment; large areas of the cementum were collagen-poor and, ultrastructurally, resembled afibrillar cementum. It is proposed that the periodontal attachment mechanism present in this case was associated with a localized failure in normal periodontal development.

DE-52 and DE-53 cellulose microcarriers. I. Growth of primary and established anchorage-dependent cells

DEAE cellulose anion exchangers having small ion exchange capacity (0.5 to 2.0 meq/g dry material) were tested for cell attachment kinetics and capacity to support growth anchorage-dependent cells. It was found that cells from established cell lines (BHK and MDCK) can grow to confluency on DEAE cellulose particles having exchange capacity of 1 and 2 meq/g dry materials, DE-52 and DE-53, respectively. On the other hand, chick embryo fibroblasts (primary cells) can grow only on DE-53 particles.

Postsurgical bone loss following root planing by ultrasonic and hard instruments

The ultrasonic scaler is currently used to plane the roots in periodontal surgery. The purpose of this study was to provide experimental evidence in support of, or against, the use of the ultrasonic scaler for root planning in periodontal surgical procedures. A notch was made through the enamel of each canine of nine adult cats. Full thickness mucoperiosteal flaps were elevated on each canine. Using hand curettes, soft tissue tags were removed from each tooth. At the maxillary right canines and mandibular left canines the roots were planed using the ultrasonic scaler, while at the maxillary left canines and mandibular right canines the roots were planed using hand curettes. A caliper was used to measure the distance from the notch to the crest of the alveolar process at each tooth. The mucoperiosteal flaps were repositioned and secured with cyanoacrylate cement. Three months postoperatively all 36 sites were reoperated and the distance from the notch of each canine to the crest of its alveolar process was measured using the caliper. The same caliper was used for all sites and the same investigator made all the measurements. Analysis of the results showed that all canines lost alveolar bone as a result of the surgical procedure, however, there was no statistical significance between the amount of bone lost on the canines where root planing was carried out by the ultrasonic scaler and the canines where the roots were planed with hand curettes. These findings support the use of the ultrasonic scaler for the planing of roots following elevation of mucoperisteal flaps and confirm its value in the practice of periodontal surgical procedures.

The influence of heart rate on ouabain cardiotoxicity in cats with spinal cord transection

The dose, serum level and ventricular content of ouabain needed to produce cardiotoxicity were examined in control cats, cats with transected spinal cords and cats with transected spinal cords whose heart rates were restored to control values by artificial pacing. The lethal dose of ouabain was higher in cats with transected spinal cords and not paced than it was in the control group. However, the lethal dose of ouabain in spinal-sectioned cats with ventricular pacing was no different from that in controls. However, in both groups of spinal-sectioned cats, death was associated with higher ventricular and serum levels of ouabain than in controls. The ventricular ouabain content of paced animals with transected spinal cords was higher than that of controls and lower than that of unpaced spinal cats. Thus, restoration of heart rate to control levels in spinal animals appeared to accelerate myocardial ouabain uptake. The lower myocardial ouabain content in the spinal-sectioned animals which were paced suggests that pacing sensitizes the heart to cardiotoxicity. Spinal section itself appears to decrease the sensitivity to ouabain partly through a decrease in cardiac rate and partly through a loss of neurogenic influence.

The keratinization potential of crevicular epithelium: an experimental study

Free grafts, consisting of nonkeratinized crevicular epithelium and supporting connective tissue, were placed into recipient beds prepared in nonkeratinized alveolar mucosa of the rhesus monkey. Four weeks later these grafts clinically resembled keratinized gingiva and this was confirmed by biopsy and histological examination. Electron microscopy indicated that the connective tissue supporting the crevicular epithelium changed to resemble that supporting keratinized gingiva in the 4-week graft. These findings were interpreted to indicate that crevicular epithelium has the potential to keratinize and that this potential is only realized when the inflammation is resolved in its supporting connective tissue.

Sutural development: structure and its response to rapid expansion

This fine structural study of the suture, its development, structure, and response to rapid expansion has shown that the sutural complex is best described in terms of the functional activity of two cell populations, namely, the osteocytic and fibrocytic series, which have the ability to remodel the tissues which they form. It is suggested that the previous detailed descriptions of differences in fiber orientation and vascular distribution reflect functional activity of a suture at any given time rather than immutable anatomic characteristics. Development of the suture and its rapid expansion showed many similarities in that growth during development and orthopedic expansion both separate the joint. If the initial inflammatory aspect of rapid expansion is ignored, the response of the suture is one of osteogenesis and fibrillogenesis, followed finally by remodeling. It is also suggested that sutural expansion involves injury followed by a proliferative repair phenomenon which, in other tissues, usually leads to the formation of scar tissue. However, the ability of sutural connective tissue fibroblasts to remodel ultimately leads to regeneration of the suture. Finally, programmed cell death has been shown to be an important feature in the development of the suture.

The role of fibroblasts in the remodeling of periodontal ligament during physiologic tooth movement

Our findings indicate a cellular basis for the connective tissue remodeling which takes place during physiologic tooth movement. This cell is the fibroblast which is capable of synthesizing and degrading collagen simultaneously and, utilizing this ability, the orderly control of collagen remodeling within the periodontal ligament is possible. It is suggested that this cellular basis of connective remodeling will have a direct significance for orthodontic tooth movement once control mechanisms have been established.

Endocrine and metabolic disordes in bronchial carcinoma

In an unselected series of 185 patients with histologically confirmed bronchial carcinoma 16 had endocrine disturbances attributable to the tumour (excluding pulmonary osteoarthropathy). Of these, 11 patients had hypercalcaemia; three inappropriate secretion of antidiuretic hormone; one Cushing's disease; three hypertrophic osteoarthropathy; and one gynaecomastia. Cushing's disease and inappropriate antidiuresis are specifically associated with oat-cell tumours, and hypercalcaemia occurs most frequently with squamous carcinoma. A negative correlation exists between gynaecomastia and osteoarthropathy on the one hand and oat-cell carcinoma on the other.