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Biomedical subjects

W J Killoy

Publications and source records attributed to W J Killoy.

At least 37 records · Page 2Linked to original sources
PubMed1996

Morphologic changes following in vitro CO2 laser treatment of calculus-ladened root surfaces.

BACKGROUND AND OBJECTIVE: The purpose of this study was to compare morphologic changes following C02 laser or manual curette treatment of calculus-ladened tooth root surfaces. STUDY DESIGN/MATERIALS AND METHODS: Laser treatment consisted of repeated single passes with a 6 Watt focused beam at 20 pulses per second, a pulse length of 0.01 second, and a manufacturer's laser efficiency rating of 86% (i.e., the amount of total power delivered through the aperture). The rate of beam passage over the target surface was controlled at 4 mm/second using an 0.8 mm diameter tip. The calculated energy density was 240 J/cm2 for each pass of the beam. Scaled and root planed surfaces were treated with a standardized force of 600 grams using new curettes. Specimens were evaluated by scanning electron microscopy. RESULTS: Laser-induced surface changes included charring, meltdown and resolidification of calculus mineral, and ablation of microbial plaque. Laser-treated specimens also exhibited residual calculus and microbial plaque deposits in areas directly adjacent to the beam path. Scaled and root planed surfaces featured smooth and/or scale like smear layers and islands of residual calculus and microbial plaque. CONCLUSIONS: The rough surface topography resulting from laser treatment and residual calculus and microbial plaque deposits indicates that C02 laser treatment of exposed root surfaces is, at best, an adjunct to traditional methods of therapy.

Dental Calculus↗
PubMed1996

Treatment of root fracture by CO2 and Nd:YAG lasers: an in vitro study.

The purpose of this in vitro study was to use scanning electron microscopy and polarized light microscopy to evaluate the feasibility of using either the CO2 laser or an Nd:YAG laser in combination with air/water surface cooling to effect fusion of fractured tooth roots. The experimental unit consisted of 81 single-rooted teeth, each with an induced root fracture. Fifty-six teeth that had been reapproximated in dental stone and 25 teeth that had been reapproximated with C-clamps were assigned to untreated control groups or groups for treatment using CO2 and Nd:YAG lasers. Laser treatment consisted of multiple passes along the line of fracture, which was inspected using a dissecting microscope after each pass until a visual indication of fusion or irreparable damage resulted. Scanning electron microscopy evaluation of the treated lines revealed heat-induced fissures and cracks, areas of cementum meltdown and resolidification, crater formation, and separation of cementum from underlying dentin. In no instance-regardless of reapproximation technique, laser type, energy, and other parameters-did the treatment effect fusion of the fractured root halves.

Argon↗
PubMed1996

Migration of human gingival fibroblasts over guided tissue regeneration barrier materials.

The purpose of this investigation was to determine the ability of human gingival fibroblasts, in vitro, to migrate along a chemotactic gradient over 3 different guided tissue regeneration barrier materials; i.e., polytetrafluoroethylene, polylactic acid, and sterile calcium sulfate. Forty petri dishes were divided into 4 equal groups. In each group of 10 dishes, a different barrier material served as the fibroblast substrate with the polystyrene floor of one group of Petri dishes serving as the control. The under agarose technique of measuring cell migration was employed using platelet derived growth factor-BB homodimer as the chemoattractant and Hanks balanced salt solution to test random migration. In addition, fibroblasts were directly cultured on triplicate sets of barrier materials and the control surface for 24 hours and examined by scanning electron microscopy. Comparative analysis of the fibroblast migration data showed the mean migration distance (adjusted for random migration) for controls to be significantly greater than any of the three barrier materials. Further, mean migration distance over calcium sulfate was significantly greater when compared to that of the polylactic acid barrier group. All other comparisons between groups were not statistically significant. Scanning electron microscopic examination fibroblasts cultured directly on barrier membranes and compared to controls indicated that the calcium sulfate substrate appeared to facilitate cell attachment and spreading whereas cells on polytetrafluoroethylene and polylactic acid barriers exhibited a morphology not conducive to migration or, in many cases, cell health. Based on these limited in vitro results and, given the 3 barrier materials considered, it would appear that calcium sulfate offers the greater potential for guided tissue regeneration in surgical sites where primary wound closure cannot be obtained.

Becaplermin↗
PubMed1996

Histologic evaluation of porcine skin incisions produced by CO2 laser, electrosurgery, and scalpel.

The purpose of this study was to histologically compare the healing of porcine skin incisions made by CO2 laser, electrosurgery, and conventional scalpel. Incisions were made on the dorsal thorax of two microswine at staggered time intervals allowing the harvest of specimens at 0, 4, 7, 14, and 21 days postsurgery at the time of sacrifice. Each of the following histologic zones were identified and measured for both laser and electrosurgery incisions: (1) zone of tissue ablation. (2) zone of thermal necrosis, and (3) width of surface damage. The depth of cut and width of surface opening was measured for the scalpel incision. Furthermore, for each specimen, the presence and character of inflammatory cell infiltrate was noted, as well as the relative times at which bridging of the incision by connective tissue and coverage of the wound by an intact epithelial layer had occurred. Results showed that in this wound-healing model, the scalpel incisions produced more defined borders, healed more rapidly, and resulted in less collateral tissue damage than those produced by CO2 laser or electrosurgery. It was also noted that to create a wound 1.29 mm in depth required at least five passes of the laser beam within the same line of incision using 206.4 J/cm2 (6 W, continuous mode).

Animals↗
PubMed1995

Evaluation of periodontal treatments using controlled-release tetracycline fibers: clinical response.

The purpose of this investigation was to evaluate the clinical efficacy of controlled-release tetracycline fiber therapy in adult periodontitis patients. One hundred-twenty-two (122) adult patients from 3 dental centers were enrolled at baseline for this study. each patient provided at least one site in each of four quadrants that was > or = 5 mm and bled on probing. One or two such sites were selected as test sites and were randomly assigned to receive one of four treatments: scaling and root planing (S), scaling and root planing plus tetracycline fiber for 10 days (SF), fiber therapy alone for 10 days (F), or two 10-day serial fiber applications (FF). After treatment, no periodontal maintenance or supportive care was provided until the end of this 12-month study. Probing depth (PD), clinical attachment level (CAL), plaque, and bleeding on probing (BOP) were measured at baseline and at 1, 3, 6, 9, and 12 months following treatment. Repeated PD and CAL measurements were taken at three locations within each site and averaged for each site. One hundred-sixteen (116) subjects completed the study. All treatments resulted in similar improvements in clinical parameters compared to baseline and were equally effective in the treatment of periodontitis as measured by probing depth reduction, clinical attachment level gain, and reduction of bleeding on probing. The clinical response, established primarily by 3 months following therapy, was generally sustained in all treatment groups for 12 months without the benefit of supportive maintenance therapy.

Adult↗
PubMed1995

Evaluation of periodontal treatments using controlled-release tetracycline fibers: microbiological response.

In a 12-month multi-center study of 116 adult periodontitis subjects, six putative periodontal pathogens were monitored by DNA probe methods in a subset of 31 subjects. Monitored species included Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn), Eikenella corrodens (Ec), Campylobacter rectus (Cr), and Actinobacillus actinomycetemcomitans (Aa) with an average detection limit of 1.8 x 10(4) bacterial colony forming units/sample. The microbiological response to four periodontal treatments was studied, one treatment in each quadrant; scaling and root planing (S), scaling and root planing with tetracycline (TC) fiber (SF), a single application of TC fiber (F) and two serial applications of TC fiber (FF). Generally two sites were sampled in each quadrant, however, in some quadrants only one site was selected. These treatments were evaluated at baseline; immediately following therapy; and post-treatment at 1, 3, 6, and 12 months. The study was conducted with a split-mouth design with no maintenance therapy over a 12-month period. At baseline, 70.8% of sites had detectable Fn; 42.9% Pg; 63.5% Pi; 29.7% Ec; 28.3% Cr; and 5.5% Aa. No significant differences were seen in baseline proportions of these species between centers. Numbers and proportions of detectable pathogens (with the exception of Pg) exhibited a triphasic temporal response: a precipitous initial decrease immediately following therapy; a rise in proportions in the 1- to 3-month post-therapy period; and a spontaneous decline in the absence of therapy over the 3- to 12-month period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Evaluation of periodontal treatments using controlled-release tetracycline fibers: maintenance response.

The purpose of this investigation was to examine periodontal disease recurrence from 3 to 12 months following various treatments with scaling and root planing and controlled-release tetracycline fibers. One-hundred-twenty-two (122) adult volunteers with at least one bleeding pocket > or = 5 mm in each of four quadrants were enrolled in this study. One or two such sites in each quadrant were selected as test sites. Quadrants were randomly assigned to receive one of four treatments: scaling and root planing (S); scaling and root planing plus tetracycline fiber for 10 days (SF); fiber therapy alone for 10 days (F); or fiber therapy alone for 20 days (FF). After treatment, no supportive care was provided during the 12-month study period. Probing depth (PD), attachment loss (AL), plaque, and bleeding on probing were measured at baseline, and at 1, 3, 6, 9, and 12 months after treatment. PD and AL measures were taken at three locations within each site and averaged for each site. Disease recurrence was defined as > or = 1 mm mean attachment loss at a site during the 3- to 12-month period. One-hundred-sixteen (116) subjects completed the study. Sites treated with SF experienced significantly (P < 0.05) less disease recurrence (4%) than S, F, or FF (9%, 10%, and 12%, respectively). Results of this study suggest that, compared to S, F, or FF, scaling and root planing in conjunction with tetracycline fiber therapy for 10 days can significantly reduce disease recurrence 3 to 12 months following treatment in the absence of supportive care.

Adult↗
PubMed1995

Histologic evaluation of alveolar bone following CO2 laser removal of connective tissue from periodontal defects.

This study was undertaken to examine histologically the healing response of alveolar bone following removal of granulation and/or connective tissues from interproximal craters by manual curettage or ablation by carbon dioxide laser. The time required to complete each type of degranulation procedure was also compared. Four interproximal treatment sites in each quadrant of two dogs were randomly assigned to each treatment modality. Neither treatment modality was totally effective in removing all suprabony connective tissue. Healing was clinically uneventful and histologically similar for both treatment groups at all time intervals. Laser-treated specimens exhibited little or no inflammatory cell infiltrate, areas of heat-induced tissue necrosis, accumulations of carbonized debris that initially was surrounded by macrophages and eventually phagocytized by multi-nucleated giant cells, and spicules of nonvital bone that exhibited a surface layer of osteoid. Although manual curettage was found to be statistically significantly faster, the difference between mean times was roughly 55 seconds and therefore unlikely to be clinically significant.

Alveolar Bone Loss↗
PubMed1994

Subgingival and interproximal plaque removal using a counter-rotational electric toothbrush and a manual toothbrush.

The purpose of this study was to compare the subgingival and interproximal plaque removal of a manual toothbrush to that of an oscillating counter-rotational electric toothbrush. Ninety teeth were divided into control, manual, and electric groups and test teeth received a total of 20 seconds of brushing. The teeth were then anesthetized, extracted, stained, dried, and examined with a computer-assisted video analysis system. The control group had 13.88% plaque-free interproximal surfaces, compared to 30.57% for the manual group and 53.23% for the electric group. The mean subgingival plaque-free measurement was 0.05 mm for the control group, 0.64 mm for the manual group, and 1.36 mm for the electric group. The differences between the means were statistically significant for both measurements.

Analysis of Variance↗
PubMed1993

Microbial colonization on natural tooth structure compared with smooth and plasma-sprayed dental implant surfaces.

The purpose of this study was to characterize and compare by scanning electron microscopy (SEM) the maturation of supragingival microbial plaque on enamel and smooth titanium and that of subgingival plaque on cementum, plasma-sprayed titanium and hydroxyapatite surfaces. Specimens (6.5 x 2 x 1 mm) were obtained from titanium implants with smooth transmucosal collars and plasma-sprayed endosseous posts of titanium or hydroxyapatite. Unerupted third molars were sectioned to similar dimensions that included equal lengths of enamel and root surface. Ten patients with post-treatment pocket depths of > 6 mm on 3 non-adjacent teeth were selected and each had 1 set of the 3 specimen types bonded by random assignment to the selected teeth. Specimens were positioned so that enamel and/or smooth titanium surfaces were supragingival and cementum and titanium or hydroxyapatite plasma-sprayed surfaces were subgingival. Patients were instructed to stop oral hygiene, after which 2 specimen sets were removed at 1, 3, 5, 7 and 10 days. Two specimens of each type were examined by SEM at each time interval for supra- and subgingival plaque. The sequence of appearance of various microbial morphotypes in supra- and subgingival plaque was similar regardless of surface. In both supra- and subgingival plaque, depending on time interval, cocci, rods of various lengths, filamentous organisms, fusiforms, spirochetes and corn-cob formations were observed. Mineralized plaque was noted on most subgingival specimens by day 10. These observations indicate that surface of natural teeth, smooth titanium and plasma-sprayed titanium and hydroxyapatite support the maturation of microbial plaque with the successive inclusion of a variety of morphotypes.

Bacteria↗
PubMed1993

Gingival crevicular blood for assessment of blood glucose in diabetic patients.

In this study 50 patients with diabetes mellitus had gingival crevicular blood from periodontal probing collected in small plastic pipettes. The pipettes transferred the crevicular blood to a non-wipe glucose self-monitoring instrument. At the same time, finger-stick capillary blood measurements were analyzed in the same glucose self-monitoring instrument, and venous blood was collected for measurement in a laboratory glucose analyzer. Each laboratory measurement was corrected from a serum glucose value to a whole blood glucose value by a function of the patient's hematocrit. This corrected glucose value allowed direct comparison of the laboratory measurement to the intraoral and finger-stick whole blood measurements. The patient blood glucose concentrations ranged from 59 mg/dl to 366 mg/dl. The gingival crevicular blood exhibited a correlation of r = 0.975 (P < .0001) to the corrected laboratory standard measurement, with a mean prediction error (bias) of -4.11 mg/dl and a root mean square error (precision) of 17.43 mg/dl. The finger-stick blood had a correlation of r = 0.983 (P < .0001) to the corrected laboratory standard, with a mean prediction error of 4.65 mg/dl and a root mean square error of 14.48 mg/dl. The American Diabetic Association recommends that the prediction error of blood glucose monitoring devices fall within 15% of the laboratory standard. Using this criterion 92% of the gingival crevicular measurements and 90% of the finger-puncture measurements fell within 15% of the laboratory value.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Effects of two toothbrushes on plaque, gingivitis, gingival abrasion, and recession: a 1-year longitudinal study.

Plaque removal is an important part of good oral hygiene. Many short-term studies have compared the effectiveness of an electric toothbrush in plaque removal to that of a conventional, manual toothbrush. Previous studies proved the electric toothbrush to be more effective on a short-term basis; however, little is known about its long-term effects. In a study that examined 32 patients over a 12-month period, the authors found electric toothbrushing to be more effective in plaque removal. The study measured the differences in abrasion, gingival recession, gingival bleeding, and plaque scores. The study also concluded that no significant gingival abrasion was caused by electric toothbrushing.

Adult↗
PubMed1993

Clinical assessment of the INTERPLAK toothbrush vs a conventional brush plus floss.

Thirty clinical recall patients from the University of Missouri at Kansas City School of Dentistry participated in a 4-week study to determine the long-term effectiveness of the INTERPLAK Home Plaque-Removal Instrument compared to manual brushing and flossing. Patients were divided into two groups, with each group using the INTERPLAK device for 2 months and the manual brush for 2 months. Patients were assessed according to measured indices for plaque, bleeding, crevice depth, and calculus. The study found that both kinds of brushes significantly reduced plaque, bleeding, and crevice depth; however, only the INTERPLAK brush reduced calculus. Improvements on all indices were greater for the INTERPLAK device than they were for manual brushing and flossing. At the end of the 4 months, most patients indicated that they would continue to use the INTERPLAK device.

Adult↗
PubMed1993

Clinical and cost effectiveness of the counter-rotational brush in private practice.

There have previously been no studies on the cost effectiveness of the use of a counter-rotational toothbrush (INTERPLAK Home Plaque-Removal Instrument), which has been demonstrated to be more effective than ordinary toothbrushes in reaching plaque-removal and gingival-health goals. Killoy et al studied the costs of required periodontal treatment for 32 patients with moderate periodontitis at two corporate capitation dental centers. The subjects were divided into two groups, a test group that brushed with a counter-rotational toothbrush and one that brushed with a manual toothbrush. Probing depth, attachment levels, and plaque and bleeding indexes in the test brush group were better than those in the control group. The end result was a mean reduction of $535 in the cost of periodontal treatment that had been planned before using the counter-rotational brush over 18 months, while the group using the manual brush experienced a mean increase of $11 in required treatment over original plans. Furthermore, the test group reached a state of gingival health, but the control group did not. The study concluded that the counter-rotational brush is cost effective.

Analysis of Variance↗
PubMed1993

Gingival response to subgingival placement of monolithic tetracycline-impregnated fibers: microscopic observations.

This study examines and characterizes the soft tissue wall of periodontal pockets after a 10-day in vivo exposure to monolithic tetracycline-impregnated fibers, with and without root planing. Four teeth from each of eight patients were randomly assigned to (1) nontreatment (controls), (2) treatment by root planing only, (3) treatment by tetracycline fiber only, or (4) treatment by scaling and root planing and tetracycline fibers. Ten days after initial therapy, all teeth were extracted with associated soft tissue pocket walls intact. Three specimens were obtained from each tooth for examination by scanning microscopy, energy dispersive spectroscopy, and light microscopy. Results indicated that use of tetracycline-impregnated fibers over a 10-day period did not adversely affect the epithelial lining and had no significant effect on the density or character of the inflammatory response present in adjacent soft tissue and confirmed the antimicrobial effects of the fibers.

Analysis of Variance↗
PubMed1992

Temperature differences at periodontal sites in health and disease.

The purpose of this study was to determine if a thermocouple probe was capable of detecting differences in temperatures between healthy and diseased periodontal sites. Twenty-two patients, 11 with radiographic evidence of periodontitis and 11 without, were probed twice with the temperature probe, and twice with a conventional probe by two examiners. Two definitions of health and disease were used. Definition one was that any site probing 5 mm or a site that bled upon probing was considered diseased. Sites 4 mm and with no bleeding on probing were considered healthy. Mean temperature differences were calculated from a baseline sublingual temperature. Each arch and tooth demonstrated different temperatures with temperatures decreasing from posterior to anterior. Differences from baseline between healthy and diseased sites were consistently higher for diseased sites. For example, maxillary second molars were 0.72 degrees C higher than baseline while the maxillary central incisors were 1.40 degrees C higher than baseline. Mean temperature differences between healthy and diseased sites were significant (P less than 0.005) for all sites. Definition two was developed since all sites 5 mm or greater and all sites which bled may not be diseased, the data were recalculated with disease including all sites greater than or equal to 5 mm with bleeding on probing and health including all sites less than or equal to 3 mm without bleeding. With this definition the mean temperature difference between healthy and diseased sites was even greater. Maxillary second molars were 0.96 degrees C higher, while maxillary central incisors were 1.76 degrees C higher.

Adult↗
PubMed1992

Serum levels of tetracycline during treatment with tetracycline-containing fibers.

Four adult patients with at least 8 teeth that had attachment loss of 5 to 10 mm which bled on probing were included in this study. Polymeric tetracycline (TCN) containing fibers were placed and left in the pockets for a period of 10 days. Plasma samples were collected at baseline, 1 hour, 3 hours, 3 days, and 10 days after fiber placement. The mean length of fiber used averaged 187 cm with a range of 160 to 222 cm. The maximum TCN dose per patient averaged 105 mg with a range of 91 to 126 mg producing no detectable serum level greater than 0.1 micrograms/ml. This level was found in 3 of the 4 subjects at 3 hours after fiber placement and in 1 subject at 3 days after fiber placement. Transient and insignificant levels of TCN became available systemically shortly after the placement of multiple fibers. The dose of TCN in each patient was well tolerated and was not associated with any serious adverse effects.

Adult↗