Binding of DNA by a dinitro-diester calix[4]arene: denaturation and condensation of DNA.

A study of a dinitro-diester calix[4]arene (5,17-(3-nitrobenzylideneamino)-11,23-di-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene) interaction with calf-thymus DNA was carried out using several techniques. The measurements were done at various molar ratios X=[calixarene]/[DNA]. Results show diverse changes in the DNA conformation depending on the X value. Thus, at low macrocycle concentrations, the calixarene binds to the polynucleotide. This interaction, mainly in groove mode, weakens the hydrogen bonds between base pairs of the helix inducing denaturation of the double strands, as well as condensation of the macromolecule, from an extended coil state to a globular state. An opposite effect is observed at X molar ratios higher than 0.07. The de-condensation of DNA happens, that is, the transition from a compact state to a more extended conformation, probably due to the stacking of calixarene molecules in the solution. Results also show the importance of making a proper choice of the system under consideration.

The incubation period of hantavirus pulmonary syndrome.

In 1993 Sin Nombre virus was recognized as the cause of hantavirus pulmonary syndrome (HPS) and the deer mouse (Peromyscus maniculatus) was identified as the reservoir host. Surveillance by the Centers for Disease Control and Prevention and state health departments includes investigation to determine the likely site(s) and activities that led to infection, an environmental assessment of the home and workplace, and possibly rodent trappings at these sites. As of December 31, 1998, there were 200 confirmed cases from 30 states (43% case-fatality ratio). The national HPS case registry was examined to determine the incubation period of HPS. Review of 11 case-patients with well-defined and isolated exposure to rodents suggests that the incubation period of HPS is 9 to 33 days, with a median of 14-17 days. Case investigations allow a better understanding of the incubation time of HPS and may define high-risk behaviors that can be targeted for intervention.

Oral discoid lupus erythematosus. A case report and review of the literature.

Literature on systemic and chronic discoid lupus erythematosus has been reviewed. The clinical and histopathologic changes in the oral cavity produced by these disorders are emphasized. A case of chronic lupus erythematosus with oral lesions is reported.

Osseous repair of a lateral periodontal cyst.

THE LATERAL PERIODONTAL CYSTS is a slow-growing radiolucent, developmental lesion occurring most frequently in males during the sixth decade. As part of the differential diagnosis, it must be distinguished from the collateral keratocyst and the gingival cyst of adults as well as other entities. Speculation remains as to the lateral periodontal cyst's developmental origin. Whether it is from reduced enamel epithelium, remnants of dental lamina, or cell rests of Malassez remains to be determined. The following longitudinal case report describes the review of literature and clinical and histologic findings as well as unusual treatment of a through-and-through perforating lateral periodontal cyst. Due to the large bony defect left after the cyst's removal, a decalcified freeze-dried bone graft was placed to close the defect. The repair of the lesion was followed for 30 months.

The gingival bleeding time index.

Recent studies have supported an emphasis on gingival bleeding indices for detection of inflammation. The purposes of the present study were: (1) to evaluate the relationships between the time necessary for stimulated gingival bleeding to occur and both gingival fluid flow and Löe's gingival index, and (2) to develop a clinical index based on gingival bleeding time. In the first part of the study, the elapsed time for gingival bleeding to first occur after sulcular stimulation was correlated with the gingival index and fluid flow on 150 gingival units. A high correlation was found between bleeding time with both the gingival index and exudate flow. A bleeding time index based on a scattergram of the data obtained in part I of the study was then formulated and evaluated in a similar fashion on an additional 172 gingival units. Results indicate a high correlation between the bleeding time index and the other indices. It is concluded that the bleeding time index may be used by itself as an accurate and objective clinical tool to evaluate gingival inflammation.

The destructive potential of electrosurgery on the periodontium.

Three cases have been presented illustrating the complications which may arise from the use of electrosurgery. These cases provide clinical evidence of the potential for severe periodontal destruction, a potential that must be weighed carefully by any practitioner who uses an electrosurgical instrument. It is suggested that new scientific studies be initiated to establish basic principles that will eliminate the hazards that now exist in the routine use of electrosurgery.

Changes in alveolar bone height and width following ridge augmentation using bone graft and membranes.

BACKGROUND: Clinical observation suggests the amount of bone height and width created during guided bone regeneration (GBR) to augment alveolar ridges is not retained during healing. A study was designed to determine: 1) whether the amount of osseous structure 4 months postoperatively after GBR was significantly less than the amount surgically created; and 2) if this change was uniform over the area treated. METHODS: Nineteen extraction sites (10 patients) were treated with GBR prior to placing endosseous implants. Allograft (DMFDB) and a bioabsorbable membrane were employed. Standardized measurements were taken of alveolar height and width 1) prior to augmentation; 2) after placement of graft and membrane; and 3) following 4 months of healing. Width measurements were taken 3 mm, 5 mm, and 10 mm from the crest at 3 intervals: the mesio-distal midpoint of the edentulous area and 3 mm mesial and distal to the midpoint. Height measurements were recorded at the mesio-distal midpoint and points 3 mm mesial and distal to the midpoint. RESULTS: Loss in width of supplemented bone after 4 months of healing ranged from 52.1% to 58.0% 3 mm from the crest, 47.6% to 67.4% 5 mm from the crest, and 39.1 % to 46.7% 10 mm from the crest. Loss of augmented height averaged 14. 7% in the center of the edentulous area but ranged from 60.5% to 76.3% 3 mm mesial and distal to the midpoint. CONCLUSIONS: The results indicate significant non-uniform loss of augmented alveolar height and width during GBR healing. The implications of these findings impact preoperative augmentation planning for endosseous implantology.

Tooth staining effects of an alexidine mouthwash.

The primary purpose of this study was to determine the amount of tooth staining produced by an alexidine mouthrinse. One hundred and eighty subjects rinsed twice daily for 1 month with either 15 ml of alexidine (0.035%) or a placebo solution. Prior to the study, the subjects were classified according to their smoking, coffee and tea drinking habits and these factors were subsequently considered in the analysis of the stain scores. Additionally, the effects on staining of a prior prophylaxis and the use of a fluoridated toothpaste during the study were determined. Upon termination of the study, subjects utilizing the active mouthrinse manifested a greater degree of staining than placebo users. The amount and intensity of the stain due to alexidine were not influenced (increased) by smoking, tea or coffee drinking habits. A prior prophylaxis did not reduce the staining propensity of alexidine users. The method of scoring developed can be used to assess the degree of tooth staining induced by antiplaque agents.

The effect of an alexidine mouthwash on plaque and gingivitis.

A clinical study was conducted on the effects of an alexidine or placebo oral rinse on plaque and gingivitis. Forty-two male subjects rinsed for 54 days while continuing toothbrushing. This was followed by 4 days of mouthrinsing only. The alexidine mouthrinse significantly reduced the plaque index when used in conjunction with toothbrushing and also when brushing was discontinued. The gingivitis results were inconclusive.

Familial benign chronic neutropenia associated with periodontal disease. A case report.

A rare case report of periodontal disease associated with familial benign chronic neutropenia is presented. The medical, dental and family histories as well as clinical and histologic observations are described and discussed.

Periodontal disease associated with preleukemic syndrome.

A case of preleukemic syndrome associated with severe periodontal disease has been presented for the first time. The clinical, radiographic and hematologic findings have been discussed, as well as medical and periodontal therapy.

Evaluation of cleansing devices in the maintenance of interproximal gingival health.

This study consisted of 24 dental students, who 10 days prior to the start of the experimental period, were thoroughly scaled and given instructions in the use of a rubber tip stimulator, unwaxed dental floss, and a modified Bass brushing technique. On day 0, the subjects had reached a high level of interproximal gingival health as measured by intracrevicular exudate flow and löe's Gingival Index. Subjects were then randomly divided into 4 groups which were to brush; brush and floss; brush and rubber tip; and brush, floss and rubber tip. Evaluation was performed on days 0, 9, 15, and 33 using Löe's Gingival Index, Podchadley's Plaque Index, and gingival exudate flow. The results of this study indicate that interproximal gingival health can be maintained in motivated patients with initially healthy gingivae (for at least several weeks) with proper use of the modified Bass brushing technique alone.

Localization of interleukin-1 beta in human periodontal tissue.

Interleukin-1 beta (IL-1 beta) is the predominant form of IL-1 produced by macrophages. IL-1 beta possesses numerous and diverse biological activities. Several of these activities, including fibroblast proliferation, potentiation of the immune response, and stimulation of bone resorption may be of relevance to the pathogenesis of periodontal disease. This study was designed to examine the presence of IL-1 beta in human periodontal tissue. An antiserum directed against the N-terminal segment (117-131) of human IL-1 beta was used to detect IL-1 beta using immunofluorescent staining techniques. IL-1 beta positive staining cells were observed in both normal and diseased tissue and were limited to the lamina propria. Brightly staining cells were increased by almost 3-fold in periodontally diseased tissue when compared to normal tissue. Low intensity staining cells were equally distributed in the normal and diseased specimens. We propose that IL-1 beta and IL-1 beta produced by cells in periodontal tissues may be related to the pathological processes associated with periodontal disease.

Juvenile periodontitis (periodontosis): current concepts.

The clinical signs and symptoms of periodontosis have been described. Although initially described as a degenerative, noninflammatory disease, recent evidence suggests that periodontosis is inflammatory, with virulent gram-negative microorganisms, selective immune deficiencies, dysfunction of polymorphonuclear leukocytes, genetic predisposition, or any combination of these as possible etiologic factors. Several authors have, therefore, advocated replacing the term periodontosis, which implies a degenerative disease, with destructive or idiopathic juvenile periodontitis. Although various treatments have been proposed, a definitive therapy for the disease depends on the future elucidation of the specific causative factors.

Periodontal and caries experience in children with insulin-dependent diabetes mellitus.

This study compared the periodontal and caries experience of young patients with insulin-dependent diabetes mellitus (IDDM) with a nondiabetic population of the same age. The plaque scores of children with IDDM were statistically higher. The caries experience of a child with closely monitored IDDM and a family history of diabetes was significantly lower than that of a child with IDDM and no such family history, even though the gingival and plaque indexes of both children were the same.

Screening for periodontal disease: radiographs vs. PSR.

This study compares the evaluation of periodontal health using bone levels measured on periapical and bitewing radiographs with clinical parameters, such as periodontal screening and recording, gingival indexes, probing depths and attachment levels. The authors found that bitewing radiographs taken within six months of the clinical examination correlated better with the clinical data than older radiographs. However, they concluded that, overall, radiographs are not highly reflective of periodontal status. PSR scores, by contrast, showed significant associations with probing depths and attachment levels. The results support use of PSR as a screening tool for periodontal diseases.

Assessment of periodontal status with PSR and traditional clinical periodontal examination.

The system of peridontal screening and recording was developed by the American Dental Association and the American Academy of Periodontology to simplify early detection of periodontal pathology. The authors evaluated the results of PSR against those of a conventional periodontal examination in 24 subjects, each of whom had a minimum of 18 natural teeth. The results of this study suggest that the PSR examination, while a useful screening tool, could be improved to further enhance its identification of patients with peridontal diseases.

Chemotherapy. A viable periodontal treatment modality?

Because bacterial plaque is composed chiefly of micro-organisms, use of chemotherapeutic agents directed against a susceptible flora would seem a conceptually valid therapeutic modality, in terms of inhibition of plaque, for the prevention and treatment of periodontal disease. The objective of treatment largely dictates the modality used. If, for example, the philosophy of treatment is elimination or reduction of pocket depth, chemotherapy against supragingival plaque may complement mechanical oral hygiene in the absence of a plaque-free environment. On the other hand, access to the subgingival flora can only be achieved through systemic administration of drugs or the use of controlled delivery systems. Notwithstanding their potential benefit as adjunctive therapy, in cases of refractory periodontitis and juvenile periodontitis in which elimination of Actinobacillus actinomycetemcomitans by mechanical debridement alone is extremely difficult, the potential for adverse reactions from the administration of antibiotics must be weighed and their use, in general, considered unwarranted. The dynamics of the inter-relationship between supragingival and subgingival plaque necessitates control of both for the successful treatment of periodontal disease. Although there are chemical agents that have been shown to be effective in the treatment of gingivitis, the evidence pertaining to their effectiveness in the treatment of periodontitis, either alone or in conjunction with conventional therapy, is inconclusive. If specific microbial floras are associated with different forms of periodontal disease, chemotherapeutic agents to which such micro-organisms are susceptible would have to be employed for their elimination. Until accurate predictors of disease activity--including definitive indicators of which particular sites are, at any one time, actively undergoing attachment loss--are available, the use of chemotherapeutic agents directed at the subgingival flora appears extremely limited and impractical. However, with the development of predictors of disease activity, including sophisticated methods of determining even small increments of attachment loss, new drugs, and a better understanding of subgingival ecologic systems, chemotherapy may yet play a significant role in the treatment of periodontal disease.

Antiplaque efficacy of a triclosan/copolymer prebrush rinse: a plaque prevention clinical study.

A 5-day, double-blind parallel clinical study was conducted to determine the antiplaque efficacy of a pre-brush rinse containing 0.03% triclosan and 0.125% of a copolymer of polyvinyl methyl ether maleic acid as compared to a matching matching placebo pre-brush rinse. A total of 114 subjects were stratified into two balanced groups according to baseline Quigley-Hein Plaque Index scores. Each group was randomly assigned to use either the triclosan/copolymer pre-brush rinse or the placebo pre-brush rinse. All subjects received a thorough oral prophylaxis at the start of the study. They rinsed their mouths twice daily (mornings and evenings) for 1 minute with 15 cc of their assigned pre-brush rinse. Immediately after rinsing, subjects brushed their teeth for 30 seconds with a commercially-available dentifrice containing 0.76% sodium monofluorophosphate and a soft-bristled toothbrush. The morning rinsing/brushing procedure was done under supervision at the clinical facility. The evening rinsing/brushing procedure was done at home. After 5 days' use of their assigned pre-brush rinse, subjects were evaluated for plaque formation using the modified Quigley-Hein Plaque Index scoring system. As compared to the matching placebo pre-brush rinse, the results showed: 1) The triclosan/copolymer pre-brush rinse provided a 28.15% reduction in plaque formation on all surfaces of the teeth. This reduction was statistically significant (P less than 0.001); 2) The triclosan/copolymer pre-brush rinse provided a 50% reduction in plaque formation on the "more difficult to brush" surfaces of the teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical plaque removal performance of two manual toothbrushes.

A single-blind, cross-over design clinical study was conducted to compare the plaque removal efficacy of the Colgate Precision Full Head soft and the Crest Complete soft toothbrushes. A total of 72 adult male and female subjects who met the inclusion/exclusion criteria completed the study. Each subject refrained from brushing for 24 hours, and was screened for dental plaque on the facial and lingual surfaces of all natural teeth using the Rustogi, et al. refinement of the Modified Navy Plaque Index (Rustogi, et al. Index). Subjects were then stratified according to the MPI and randomly assigned to one of two groups. Subjects returned one week later having abstained from all oral hygiene procedures for a 24-hour period. At this visit, each subject was evaluated for plaque, then brushed with his/her assigned toothbrush for 60 seconds, and again scored for plaque after brushing. Subjects were instructed to resume their normal routine and return to the clinical site one week later. At this time, the alternate toothbrush was assigned to each group in a cross-over design. Plaque evaluations and toothbrushing procedures were again performed. Data were statistically analyzed, and the Colgate Precision toothbrush was demonstrated to be significantly more effective (p < 0.01) in removing whole mouth, gumline, and interproximal area plaque.