The penetration of lavage solution into the periodontal pocket during ultrasonic instrumentation.

The purpose of this study was to evaluate the penetration depth of the water coolant for medicament lavage of an ultrasonic device into the periodontal pocket. Patients having teeth previously planned for extraction, and exhibiting probing depths 3 mm or greater were used in this study. A reference notch was placed on the tooth at the level of the gingival margin and the probing attachment level (PAL) was measured from the base of the notch to the base of the pocket. The ultrasonic device, with an EWPP tip and equipped with a reservoir of erythrocin dye colored coolant, was activated and moved in a vertical direction from the gingival margin to the apical extent of the pocket. The tooth was extracted and the penetration depth (PD) of the dye-colored water spray was measured from the reference notch to the apical limit of the stained subgingival plaque. The tooth was counter stained with methylene blue to determine the coronal extent of the connective tissue attachment. Pearsons' Product Moment Correlation Coefficient for the PAL and PD was calculated. Dye-stained root surface was observed along the full extent of the probe tip's penetration path. The dispersion of the dye-colored stain was localized to the area of the ultrasonic probe with very little lateral dispersion. The ultrasonic instrument may be an effective system to mechanically remove plaque and calculus at the same time as delivering a chemotherapeutic agent. The limited dispersion of the liquid dye would indicate that chemical plaque control with this delivery system is dependent upon thorough debridement with the instrument such that all affected surfaces are instrumented.

The presence of nicotine on root surfaces of periodontally diseased teeth in smokers.

There is a growing body of scientific evidence to support the concept that the use of tobacco products significantly contributes to the progression of periodontal disease or is detrimental to healing following periodontal therapy. Several studies have shown toxic effects of nicotine on peripheral circulation and the immune response. The purpose of the present study was to identify and compare the quantity of nicotine present on root planed and nonroot planed surfaces of teeth from smokers. Twenty-nine single-rooted teeth from 11 smokers were extracted, brushed clean, and the roots sectioned longitudinally. The respective halves were either left untreated (Group A) or thoroughly root planed (Group B). Pulpal tissue was removed and the individual root sections weighed. Each half was extracted for nicotine using a methylene chloride technique. Quantification was performed using high pressure liquid chromatography (HPLC) and the sections compared on a nicotine per root weight basis. Results showed a greater amount of nicotine present on non-root planed sections than on treated sections, although some treated specimens revealed small amounts of the substance. These findings suggest that nicotine is present on the root surface but is largely removed by thorough root planing. Its presence is not surprising in light of the recent finding that nicotine and cotinine, the major metabolite of nicotine, are found in gingival crevicular fluid. Recent studies have shown a particularly harmful effect of nicotine on fibroblasts. Its presence on root surfaces may, therefore, impair wound healing and alter the host response in periodontal disease. The use of tobacco products in conjunction with periodontal therapy may interfere with optimal healing and/or lead to further periodontal breakdown.

Effectiveness of sodium fluoride on tooth hypersensitivity with and without iontophoresis.

The purpose of this study was to assess the short and long term reduction of dentinal hypersensitivity by a single application of sodium fluoride with and without iontophoresis. Two teeth in each of 16 patients were blindly evaluated before and after treatment, and at 1, 3, and 6 months. A blast of air and tactile pressure were used to assess pain. Results indicate that there is significant, immediate reduction in dentinal hypersensitivity with the use of iontophoresis that is lost with time. The use of sodium fluoride alone had no effect. Sodium fluoride with iontophoresis was demonstrated to have an immediate post treatment effect (P less than .001) that lasted through the 3-month observation period. The data suggest that iontophoresis may be a useful adjunct to sensitivity therapy and that an immediate therapeutic effect may be achieved. The efficacy of the use of sodium fluoride alone is obscured by the natural reduction of root sensitivity observed with time.

A comparison of mandibular lingual surgical flaps with and without a vertical releasing incision.

The purpose of this study was to evaluate the short-term postoperative pain for surgical flaps with mandibular lingual vertical releasing incisions (ML-VRI) compared with envelope flaps and to observe the postoperative clinical healing of ML-VRI. Using a split mouth design, 12 adult periodontal patients received bilateral posterior mandibular surgery with an envelope flap on one side and a flap with an ML-VRI on the contralateral side. Surgical procedures were performed at separate appointments, varied in order, and performed an equal number of times on the right and left sides. Postoperative pain was scored by the patients, and scores for each technique were compared using an analysis of variance and covariance with repeated measures. Photographs were used to assess postoperative clinical healing of ML-VRI with various degrees of initial closure. Results indicated no significant statistical difference (P greater than 0.05) between pain levels for the two surgical techniques. There was complete clinical healing despite variations in the degree of closure of ML-VRI. The findings of this study support the use of ML-VRI. They are indicated in areas with flat contours or with slight ledges and inferior concavities. ML-VRI are contraindicated in areas with prominent ledges and inferior concavities and in areas with exostoses. Suturing the vertical incision is unnecessary and may be detrimental to the tissues. A "step down" incision that preserves attachment levels in nondiseased sites is discussed.

In vitro attachment of human gingival fibroblasts to endosseous implant materials.

In recent years, the focus of dental implant research has been the nature of the bone-implant interface associated with osseointegration, yet the transgingival portion of endosseous dental implants has received little attention. The purpose of this study was to determine the attachment of human gingival fibroblasts to three different implant materials: commercially pure titanium, non-porous hydroxyapatite, and porous hydroxyapatite. Cell attachment was quantified by radiolabeling gingival fibroblasts with tritiated thymidine and counting attached cells by liquid scintillation following incubation for periods of 20, 40, and 60 minutes. Additional studies coating implant surfaces with fibronectin were also performed. The nature of the implant material itself appeared to affect the number of attached cells. Determined on a surface area basis, fibroblast attachment was greatest to titanium followed by non-porous hydroxyapatite. Porous hydroxyapatite demonstrated the least amount of fibroblast attachment. When incubated with fibronectin at a concentration of 50 micrograms/ml, no increase in the number of cells attached to the various implant materials was observed. A small but statistically significant increase in the number of fibroblasts attached to porous hydroxyapatite at 40 minutes was observed when implant materials were pre-treated with fibronectin.

An in vivo study of dentin sensitivity: the relation of dentin sensitivity and the patency of dentin tubules.

Dentin hypersensitivity can be a major problem for periodontal patients. The relationship between dentin hypersensitivity and the patency of dentin tubules in vivo has been established. Thirteen adult patients with teeth scheduled for extraction were selected and a stent fabricated to confirm location of the root surface being examined. Response to a constant air blast was recorded on a numeric pain rating scale (from 0 to 4) during the course of treatment. The tooth surface was initially treated with 0.5 molar EDTA (pH = 7.4), to remove the smear layer and expose tubules. The region was then treated with either a 3% monopotassium-monohydrogen oxalate solution or a 3% sodium chloride solution, both at pH = 2.4. Solutions were prepared to be indistinguishable to the examiner. Response to air was evaluated before and after EDTA treatment and after treatment with a desensitizing agent. The patient was anesthetized and the treated tooth extracted. Specimens were sectioned, critical point dried, sputter coated with gold, and examined under the scanning electron microscope. Photomicrographs were analyzed by computer assisted digital analysis to evaluate the degree of tubule occlusion. Statistical analysis by repeated measures ANOVA for univariate tests of hypothesis for within subject effects showed the sodium chloride solution was more effective in reducing dentin sensitivity than the potassium oxalate solution. Scanning electron micrographic analysis revealed a mean dentin tubule aperture size of 1.720 square microns following EDTA treatment alone, 0.564 square micron following potassium oxalate treatment, and 0.386 square micron following sodium chloride treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Cotinine in saliva and gingival crevicular fluid of smokers with periodontal disease.

A study was undertaken to determine the presence of cotinine, a metabolite of nicotine, in the saliva and gingival crevicular fluid of smokers with periodontal disease. Saliva and crevicular fluid samples were obtained from 16 habitual cigarette smokers and analyzed by High Performance Liquid Chromatography (HPLC) for the presence of cotinine. Thirteen non-smokers with periodontal disease served as controls. There was no evidence of cotinine (within our detection levels) in either the saliva or crevicular fluid of any of the nonsmokers. Cotinine, in a wide range of concentrations, was detected in the saliva and crevicular fluid in all of the 16 cigarette smokers. The presence of a nicotine metabolite in the saliva and gingival crevicular fluid reflects the extent of the systemic distribution of nicotine in smokers. The vasoactive properties of nicotine are well known and may possibly affect the pathogenesis of periodontal disease.

Microbiologic characterization of ligature-induced peri-implantitis in the microswine model.

The purpose of this study was to evaluate the microbiologic changes associated with induction of peri-implantitis in the microswine. A split-mouth design was utilized. Three implants were placed in the edentulous mandibular bicuspid region of 2 microswine yielding 12 implants for evaluation. The experimental implant abutments were ligated with 4-0 silk suture material to induce peri-implantitis for a period of 45 days. The control implant abutments were not ligated. The control implants were scaled and cleaned at each time interval using plastic scalers. The attachment level (AL), probing depth (PD), gingival index (GI), and plaque index (PI) were measured at day 0 (baseline) and days 14 and 45. Microbiologic samples were taken from the "sulcus" with paper points at each interval and were dispersed in prereduced media; plated on selective and non-selective media; and grown under aerobic, anaerobic, and capnophilic atmospheres. A greater AL, increased PD, and higher GI and PI scores were noted among the experimental implants. The controls remained essentially unchanged. Radiographs revealed that experimental implants showed an increased amount of bone loss when compared to control. Bone loss caused the implant threads to be exposed in the experimental implants. Microbiologic studies revealed that there was a shift from Gram-positive facultative organisms to Gram-negative obligate anaerobes, including black pigmented Bacteroides, in experimental implants. The microbiota of the control implants remained primarily Gram-positive facultative organisms. The microswine appears to be a suitable animal model for evaluation of osseointegrated implants. Importantly, under the experimental conditions reported, osseointegrated implants were susceptible to "periodontal" breakdown or peri-implantitis.

Dentinal tubule occlusion and root hypersensitivity.

Previous studies have established that root sensitivity is due in part to open dentinal tubules at the root surface. The purpose of this study was to longitudinally evaluate the occlusion of dentinal tubules by various clinical procedures including scaling and root planing and the application of potassium oxalate. A model was developed to evaluate dentinal surfaces in vivo. Six 2 mm x 3 mm sections were taken from the roots of extracted teeth immediately below the CEJ. One half of the treated dentin samples from each donor was incorporated into the removable denture worn by the donor and the other half served as baseline. The dentin samples were evaluated at 1 week by scanning electron microscopy. At day zero no open tubules were observed in any of the samples due to the presence of a smear layer or oxalate crystals. Evaluation of root planed samples revealed that by 7 days the tubules had re-opened. The samples which had been treated with potassium oxalate showed few oxalate crystals by 7 days revealing open tubules. Control samples were etched with EDTA and evaluated in the same manner. Although the number of tubules did not significantly change in the EDTA etched control samples, the diameter of the tubules dramatically decreased by 4 weeks. It can be concluded that the creation of a smear layer or application of oxalates to occlude dentinal tubules to reduce sensitivity are relatively short-lived. These procedures may provide patient comfort prior to natural occlusion of the tubules.

The effect of chlorhexidine treatment of root surfaces on the attachment of human gingival fibroblasts in vitro.

Chlorhexidine mouthrinse is a widely used adjunct in periodontal therapy due to its bactericidal effects. The effect of this agent on chronic gingivitis and wound healing following surgical therapy in animals and humans has been favorable. The re-establishment of lost connective tissue attachment to the root surface following periodontal therapy is a desirable goal in which the ability of periodontal ligament fibroblasts to reattach to root surfaces of periodontally involved teeth is a critical event. Understanding the effect of chlorhexidine on fibroblast attachment will provide the rationale for its use during the healing phase of periodontal surgery. For this study, impacted third molars were sectioned into 4 pieces. Groups of 10 root pieces were exposed to 0.12% chlorhexidine or saline for 3 minutes followed by a distilled water rinse. The root pieces were incubated with human gingival fibroblasts (HGF) using standard tissue culture techniques for 1, 2, 4, 6, and 8 hours. HGF were prelabeled with 3H-thymidine to a standard specific activity. The surface area of each root piece was determined and the attached cells quantified by using scintillation spectroscopy. The number of cells per unit area was then calculated and the data expressed as cells/mm2. The repeated measures design was statistically analyzed by repeated measures analysis of variance. There was a significant difference between the number of attached cells in the chlorhexidine and the control groups (P less than 0.001). Exposure of root surfaces to chlorhexidine significantly inhibits subsequent fibroblast attachment which may interfere with regeneration of the periodontium. Hence, the data suggest that efforts should be made to minimize chlorhexidine contact with the root surface with physical barriers.

A comparison of T4:T8 lymphocyte ratio in the periodontal lesion of healthy and HIV-positive patients.

Previous reports describe a characteristic, rapidly progressive, periodontitis that is unique to patients who are seropositive for HIV antibody (Western blot +). The purpose of this study was to compare the T4 and T8 lymphocyte subpopulations in the peripheral blood and periodontal lesions of these HIV patients with those of healthy controls. T-cell subsets in peripheral blood were quantified by flow cytometry. The values from this analysis were used to calculate the peripheral T4:T8 lymphocyte ratio for each patient. Gingival tissue (papilla) was obtained from 8 HIV+ patients and from 6 healthy HIV- control patients during routine gingival surgery. The T-cell subpopulations in the gingival tissue were determined using serial cryostat sections that were labeled with monoclonal antibodies for T4 and T8 cells and developed using an avidin-biotin-peroxidase system. Six sections were taken from each of the 14 tissue specimens (one per patient). The sections were examined at 450 x and the mean number of T4 and T8 cells calculated for each section. These mean values were then used to determine the T4:T8 lymphocyte ratio for each tissue specimen. The peripheral blood analysis revealed a mean serum T4:T8 ratio of (2.07 +/- 0.455) for the controls and (0.58 +/- 0.26) for the HIV patients. The significantly lower T4:T8 ratio in HIV patients is consistent with their diagnosis. Although the results indicated that the mean T4:T8 lymphocyte ratio in the gingiva of controls was highly variable (2.70 +/- 1.344), the gingiva of HIV patients consistently exhibited a complete absence of T-cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of titanium dental implant osseointegration in posterior edentulous areas of micro swine.

This study investigated the micro swine (Sus scrofa) as an animal model for research in osseointegrated implant systems. As the first in a series of investigations based on this model, the study focused on the histological evaluation of the bone-implant interface of Brånemark implants. Ten titanium implants were placed in posterior edentulous areas of the swine for longitudinal evaluation of healing and osseointegration. Six-week and 18-week post-operative specimens were removed en bloc at the time of death. The samples were fixed in glutaraldehyde, embedded in acrylic, and sectioned with a diamond wafering saw. The specimens were viewed under SEM and photographed. The percentage of bone that was in direct contact with the coronal, middle, and apical segments of the implant, referred to as the contact length fraction (CLF), was determined by use of a digitizing analyzer. All implant fixtures became exposed through the soft tissue within one week of placement. Of the ten titanium fixtures placed, three failed--one by post-surgical day 14 due to food impaction into the surgical site, and the other two because of failure to osseo-integrate. Bone contact with the successfully integrated implant surfaces ranged from 19.2 to 58.5%, with a mean of approximately 34%. Osseointegration did not appear to increase over the experimental time period, since there was no difference in the percentage of bone contact between the 18-week and the six-week specimens. The lack of soft-tissue coverage over the implants caused bone loss, but did not significantly affect osseointegration in the coronal third. The micro swine appears to be a suitable animal model for use in implant research in posterior edentulous regions.

Correlation of subclinical candidal colonization of the dorsal tongue surface with the Walter Reed staging scheme for patients infected with HIV-1.

The correlation between subclinical candidal colonization of the dorsal tongue surface and the Walter Reed staging scheme for patients positive for human immunodeficiency virus (HIV-1) antibody is reported. Of 76 cytologic smears of the dorsal tongue surface, 12 (16.2%) demonstrated subclinical colonization. The mean peripheral helper T-lymphocyte count for patients with subclinical colonization was 304 +/- 226 cells/mm3 and was not significantly different from seropositive patients without colonization (411 +/- 209 cells/mm3). The Walter Reed scheme for assessing progressive immunodysregulation did not significantly correlate with the presence of subclinical colonization. This study suggests a more complex pathogenesis for oral candidiasis in HIV-1-infected patients rather than a direct link to peripheral helper T-lymphocyte depletion below a count of 400 cells/mm3.

Toxic effect of ethylene-oxide-sterilized freeze-dried bone allograft on human gingival fibroblasts.

Freeze-dried bone allograft (FDBA) which either had or had not been sterilized by exposure to ethylene oxide (EtO) prior to lyophilization was obtained from two commercial sources. EtO-sterilized FDBA was reexposed to EtO as a positive control. Gas chromatograph assays revealed that three out of four commercially obtained EtO sterilized FDBA had no detectable EtO, with one sample having 0.21 parts per million (PPM). Surprisingly, 0.24 PPM was detected in one sample which had not been sterilized with EtO gas. This was presumed due to contamination from a gas-sterilized rubber stopper. In the cell toxicity study, FDBA and human gingival fibroblasts (HGF) were added simultaneously, incubated for 72 h, and fixed and stained. Samples of FDBA sterilized with EtO which were free of EtO did not alter HGF growth. However, the positive control FDBA which contained 0.72 PPM EtO had a deleterious effect on HGF. FDBA with EtO residuals caused morphologic change in HGF.