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Publications and source records attributed to Charles M Cobb.
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BACKGROUND: It has been speculated that periodontal probes can transmit periodontal pathogens from site to site. The purpose of this study was to evaluate the potential for bacterial transmission as a function of periodontal probe design. METHODS: Four different periodontal probes were used to measure probing depths ranging from 0 to 3 mm and > or = 4 mm. Following measurement of each pocket, probes were transported to a laboratory and cultured on blood agar, and colony forming units (CFUs) were determined for total aerobic, anaerobic, and dark-pigmented colonies (DPCs). Eight randomly selected probe tips, representing each probe type and probing depth category, were selected for examination by scanning electron microscopy (SEM) to determine distribution and morphotypes of adhering microbes. RESULTS: Results showed no statistically significant main effect for probes with respect to CFUs. However, there was a statistically significant increase in CFUs for deeper pockets when compared to pockets 0 to 3 mm. SEM observations were consistent among groups, regardless of probe design or probing depth. All probes exhibited a rough surface texture. Microbes were observed as single organisms or in aggregates and were adherent along the entire length of the probe up to the maximum probing depth. CONCLUSIONS: There was no difference in CFUs obtained as a function of periodontal probes. The rough surfaces of the probes used in this study likely promoted bacterial adherence through two different mechanisms: through scraping of the pocket walls by the roughened surfaces of the probe and by the high surface-free energy of the metal probes, facilitating bacterial adherence.
The purpose of this study was to examine by transmission (TEM) and scanning electron microscopy (SEM) the supragingival microbial plaque overlying the ulcerated gingival papillae of necrotizing ulcerative periodontitis (NUP) lesions in HIV-seropositive patients. The microbiota of NUP and HIV-seropositive patients with periodontitis has been reported to be similar to that of conventional periodontitis in non-infected subjects, although several investigators have also reported high recovery rates of microbes not generally associated with the indigenous oral microbial flora. Light and electron microscopic observations and microbial culture studies indicate a similar high prevalence of spirochetes in both necrotizing ulcerative gingivitis (NUG) and NUP. In addition, several studies have reported more frequent isolation of Candida albicans from diseased periodontal sites in HIV-seropositive patients than from non-diseased sites. Ten male and six female patients, each HIV-seropositive and exhibiting NUP, constituted the study population. Two biopsies of involved gingival papillae from between posterior teeth were obtained from each patient and processed for examination by both TEM and SEM. Microscopic examination revealed a surface biofilm comprised of a mixed microbial flora of various morphotypes in 81.3% of biopsy specimens. The subsurface flora featured dense aggregations of spirochetes in 87.5% of specimens. Zones of aggregated polymorphonuclear leukocytes and necrotic cells were also noted. Yeasts were observed in 65.6% of specimens and herpes-like viruses in 56.5% of the specimens. Collectively, except for the presence of yeast and viruses, the results suggest that the microbial flora and possibly the soft tissue lesions of NUP and necrotizing ulcerative gingivitis are very similar.
BACKGROUND: A review of the periodontal literature offers little information concerning trends in referral patterns of patients for periodontal therapy. Over the last 2 decades, there has been a significant increase in the knowledge base concerning inflammatory periodontal disease. It might be assumed that the collective advances in knowledge have impacted periodontal referral patterns. Thus, the purpose of this study was to examine the differences in periodontal referral patterns in the same offices separated by a 20-year interval (i.e., 1980 and 2000). METHODS: A retrospective chart analysis was conducted on a total of 782 patient charts from three conveniently selected periodontal practices. Charts were randomly selected from two time periods: 1980-1981 and 2000-2001. The following information was obtained from each patient record: gender, age at time of initial examination, tobacco smoking status at time of initial examination, periodontal case type, number of missing teeth at initial examination (not including third molars), and number of teeth scheduled for extraction per periodontal treatment plan. Descriptive data were analyzed using frequency distributions, measures of central tendency, and measures of dispersion. Non-parametric statistics were used to examine the relationship of disease severity as a function of site, time period, and patient age. RESULTS: The following trends were noted: 1) an increase in the average age of patients at the time of the initial examination; 2) a decrease in the percentage of patients using tobacco at the time of the initial interview; 3) an increase in the percentage of periodontal Case Type IV patients with a concomitant decrease in the number of periodontal Case Type II patients; 4) an increase in the average number of missing teeth per patient at the initial examination; and 5) an increase in the average number of teeth scheduled for extraction per periodontal treatment plan. CONCLUSIONS: Characteristics of patients referred in 1980 compared to those referred in the year 2000 indicate that, although fewer patients used tobacco, there were several noteworthy trends. At referral, patients exhibited a greater loss of teeth, had more severe disease, and required extraction of a greater number of teeth in 2000 compared to 1980. Possible reasons for these trends are discussed.
BACKGROUND: In AIDS patients who present with an oral neoplasm, Kaposi sarcoma is the tumor most frequently encountered, comprising 50% to 80% of all tumor occurrences. However, oral Kaposi sarcoma associated with erosion of underlying bone is a relatively rare finding. This report and review of the literature documents a case of AIDS-related oral Kaposi sarcoma exhibiting severe bilateral erosion of the maxillary alveolar ridges. METHODS: An HIV-seropositive male with extensive maxillary Kaposi sarcoma and associated bilateral alveolar bone erosion presented for dental evaluation subsequent to radiation therapy. Clinical and radiographic examinations were performed. Medical and dental histories were procured and supplemented with consultations from the patient's primary physician and radiation oncologist. Maxillary edentulation with surgical revision for primary closure was the treatment of choice for management of the dentoalveolar pathology. A maxillary immediate treatment denture was designed to obturate anticipated antral communications with the maxillary sinus. RESULTS: Surgical and prosthetic treatments were completed, but complicated by an oral-antral perforation that subsequently healed without complication. Soft tissue biopsies obtained during surgery revealed no evidence of residual Kaposi sarcoma. CONCLUSIONS: Although AIDS-related oral Kaposi sarcoma is a relatively common finding, erosion of subjacent alveolar bone is uncommon. Treatment of the tumor with subsequent dental reconstruction can be complicated by the severe lack of bone, surgical perforation of the maxillary sinus, and lack of stable teeth to serve as abutments. Significant advances in understanding the pathogenesis of AIDS-related Kaposi sarcoma have occurred in the last decade. HHV-8 and various inflammatory cytokines have been implicated in the pathogenesis and are likely to become the primary targets for therapeutic intervention.
BACKGROUND: Stress and anxiety alter respiratory rate and thereby alter oxygen saturation in the blood. Management of psychological stress in the dental office may help maintain blood gas homeostasis. One method of stress management is through the use of preoperative oral sedation. METHODS: The study population consisted of 13 patients scheduled to receive two quadrants of periodontal surgery at two different appointments. A randomized split-mouth crossover design was used with one quadrant of surgery involving preoperative oral sedation (diazepam) and local anesthetic, and the second using local anesthetic only. Oxygen saturation was monitored by pulse oximetry, which recorded the number of times saturation dropped below 95% in a given time period. Data were recorded at 5 time periods: 1) baseline; 2) from time of anesthetic administration to 20 minutes into surgery; 3) 21 to 40 minutes; 4) 41 to 60 minutes; and 5) 61 to 80 minutes into the surgery. Data were analyzed by a two-factor repeated measures ANOVA. The two within-group factors were treatment group and time. RESULTS: Results indicated no significant interaction between time and treatment (P > .05). However, data for groups over time suggested a trend supporting an interaction. The eta2 value of 0.124 suggested a moderate effect favoring the diazepam treatment. No significant difference was noted for the main effect of treatment and time. However, the eta2 value of 0.24 for treatment effect (diazepam versus no diazepam) suggested a meaningful difference between groups. Similarly the eta2 value of 0.135 for time suggested a moderate effect over time within-subjects. CONCLUSIONS: This study indicates that diazepam given orally in adult dosages does not cause significant respiratory depression, and is generally safe for those healthy patients who may require slight to mild sedation during periodontal surgery.
BACKGROUND: Although fibronectin (FN) is an important extracellular glycoprotein involved in periodontal wound healing, it is not clear whether the application of exogenous fibronectin (ExoFN) offers any clinical benefit. The purpose of this preliminary in vitro study was to determine the binding of FN from three different sources, viz. endogenous EDTA-plasma, endogenous serum and exogenous commercial purified human fibronectin in PBS buffer, to demineralized and non-demineralized root powder. METHOD: The binding of FN to a known quantity of mineralized and non-demineralized root powder by overnight incubation at 15 degrees C was studied by enzyme immunoassay (EIA) technique. The criteria for optimal performance of EIA procedure for the determination of FN was established. Particle size of powdered root structure was standardized using a Vibratory Sieve Shaker. RESULTS: The EDTA-plasma and the serum FN exhibited binding of (17.8 +/- 2.1 microg) and (6.5 +/- 4.5 microg), respectively, to the non-demineralized root powder. However, the binding was only significant for the EDTA-plasma FN (p < 0.01) when compared to controls. In the demineralized group there was no ascertainable binding of FN from either endogenous or exogenous sources. ExoFN in buffer exhibited no binding at all to the non-demineralized or demineralized root powder. CONCLUSION: The preliminary data suggest that additional plasma and serum factors may facilitate the binding of FN to root powder. High levels of FN in blood do not necessarily indicate that FN is available for binding to the root surface during periodontal surgery.
BACKGROUND: The purpose of this study was to determine the total root surface area of extracted teeth by computerized image analysis and the amount of remaining attachment area assuming various amounts of bone loss due to periodontal disease. METHODS: One hundred fifty extracted mandibular teeth were evaluated, and measured from cusp tip to the cemento-enamel junction (CEJ), CEJ to root apex, and cusp tip to root apex. The fulcrum point of the tooth was also measured, along with the total root surface area of attachment and total surface area of attachment remaining following simulation of attachment loss in 2 mm increments. Measurements were made on 80 teeth on one proximal surface and either the buccal or lingual surface and multiplied by a factor of 2. Measurements on 70 teeth were made on all 4 root surfaces to predict the accuracy of measuring only 2 surfaces to determine root surface area. Images of the tooth surfaces were obtained by video camera and converted to computer image with measurement of the surface areas. RESULTS: The total root surface area for the mandibular cuspids and first and second bicuspids was 275.88 mm2, 251.45 mm2, and 271.81 mm2, respectively. The 2-sided and 4-sided measurements for the mandibular first bicuspid were 252.55 mm2 and 247.02 mm2, respectively (P>0.05). CONCLUSIONS: This study found the total root surface area to be greater than that in most previous studies. Increasing attachment loss is related to decreasing root surface area; however, this relationship is not directly proportional. No statistical difference was found between measuring 4 surfaces versus only 2 surfaces.
Analysis of Egyptian hieroglyphics and medical papyri indicate that non-surgical periodontal treatment was common 3000-4000 years ago. Even today, scaling and root planing (SRP) remains an essential part of successful periodontal therapy. The collective evidence from numerous clinical trials reveals a consistency of clinical response in the treatment of chronic periodontitis by SRP using manual, sonic, or ultrasonic instrumentation. Thus, SRP remains the 'gold standard' to which more recently developed therapeutic modalities must be compared. Inherent to the clinical evaluation of SRP are such concerns as manual versus sonic and ultrasonic instrumentation, control of sub-gingival bacterial populations, removal of calculus, root smoothness and changes in various clinical parameters, e.g. probing depth, attachment levels, bleeding on probing and gingival inflammation. Lastly, an abbreviated discussion is presented on a relatively new paradigm of complete mouth 'disinfection' in a compressed time-frame that includes SRP as a significant component of the treatment regimen.
The purpose of this study was to evaluate how time-dependent waterline flushing affects the presence of biofilm in otherwise-untreated dental unit waterlines (DUWLs). Water samples were obtained from twelve highspeed handpiece DUWLs located in the undergraduate treatment clinic at the University of Missouri-Kansas City, School of Dentistry. Baseline water samples (50 cc) were collected prior to the start of continuous flushing. Additional 50 cc samples were collected after two-, three-, and four-minute flushing intervals from the baseline. The levels of planktonic bacteria in DUWLs were quantified by counting colony forming units (CFUs). In addition, segments of water tubing from each of the highspeed handpiece waterlines were examined by scanning electron microscopy, which confirmed the presence of a residual biofilm in the lumen of each dental unit waterline. A one-factor repeated measures ANOVA showed a statistically significant (p<0.01) reduction in CFUs at all intervals compared to baseline and between each successive time interval. Indeed, after four minutes of continuous flushing, all waterlines still harbored CFU levels that exceed current American Dental Association (ADA) recommendations. It was concluded that water flushing of DUWLs produced a statistically significant reduction in planktonic bacteria at each time interval compared to the baseline and between each successive time interval. However, the level of CFUs after four minutes of continuous water flushing still exceeds the current ADA recommendations for acceptable levels of microorganisms.
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