摘要:

Lasers may be useful in uncoveringsubmerged implants or in removing contaminants from “ailing” implants. The purposes of this study were to record temperature changes at the bone‐titanium implant interface when using a CO2laser to: 1) uncover the implant at second stage surgery; and 2) “decontaminate” exposed implant threads. Scanning electron microscopy (SEM) was used to characterize surface changes of lased implants, both uncontaminated or contaminated with blood or saliva. In part one, 28 titanium implants, measuring 3.75 mm by 7 to 20 mm, were placed into room temperature, fresh, resected pig mandibles and covered with a flap of gingiva. The overlying tissue was removed with a CO2laser at different power levels. Bone‐implant interface temperatures were measured with a thermocouple near the top of the implant, and 5 to 7 mm apical to the osseous crest. The effects of implant size, power level, tissue thickness, and operation time were evaluated. In part two, 5 mm by 4 mm bony dehiscences were created on 3 implants in one mandible and the exposed fixture threads lased at varying times and power levels. The results from part one showed temperature increases at the top thermocouple ranged from 4.2 to 16.8°C and increases at the bottom thermocouple ranged from 2.0 to 11.5°C. The results from part two showed temperature increases at the top thermocouple ranged from 1.2 to 11.7°C and increases at the bottom thermocouple from 0.0 to 5.0°C. If baseline ambient temperatures are 37°C, then the temperature at the bone‐implant interface might exceed 50°C. SEM revealed no gross surface changes in lased uncontaminated implants, but laser treatment alone of contaminated implants failed to completely remove saliva or blood. Further study is needed regarding temperature increases and surface changes induced by lasers that may adversely affect osseointegration.J Periodontol 1995;66:1017–1024.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1017

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

To elucidate the characteristicsof human periodontal ligament cells, we compared these cells with gingival fibroblasts isolated from the periodontal tissues of female human subjects. Human periodontal ligament (HPDL) cells had a sharper spindle shape and exhibited a higher growth rate than human gingival fibroblasts (HGF). HPDL cells had a high level of alkaline phosphatase (ALPase) activity, whereas HGF had a low level of such activity. Northern blot analysis demonstrated that HPDL cells produced ALPase mRNA. Decorin and biglycan mRNA were detected in both HPDL cells and HGF, whereas osteocalcin and bone sialoprotein mRNA was not detected in either cells. Both HPDL cells and HGF responded to Prostaglandin E2(PGE2) and isoproterenol, and produced cyclic AMP (cAMP), but did not respond to human 1‐34 parathyroid hormone (PTH). Intracellular Ca2+([Ca2+]i) was measured in HPDL cells and HGF, using Fura 2‐AM. Bradykinin (BK) and histamine (HIS), which are major chemical mediators, caused a transient rise of [Ca2+]iin the presence of extracellular Ca2+. In HGF, but not HPDL cells, HIS induced a biphasic transient peak in [Ca2+]i. BK and HIS increased PGE2release in both HPDL cells and HGF. However, HGF released a larger amount of PGE2than HPDL cells. These results demonstrate that HPDL cells have quite different characteristics from HGF. HPDL cells proliferate at a higher rate than HGF, show higher levels of cAMP production and greater ALPase activity, and respond in a different fashion to chemical mediators (BK and HIS) compared with HGEJ Periodontol 1995;66:1025–1031.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1025

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

Effects ofNd:YAGlaser irradiationon untreated and root planed tooth roots were investigated to determine whether a cleaning effect and/or removal of smear layer could be achieved without concomitant microstructural or thermal damage. Sixty (60) healthy extracted teeth were either untreated, irradiated only, root planed only, or irradiated and root planed. Intra‐pulpal and surface temperatures were monitored during irradiation, then SEM was performed. Smear layer elimination was achieved without inducing hard tissue microstructural damage at 5W, using pulse durations and intervals of 0.1 s, a fluence of 0.77 J/cm2, and a total energy density of approximately 700 J/cm2. However, these results were not consistent in all samples. At these parameters, intra‐pulpal temperature increases of 9 to 22°C and surface temperature increases of 18 to 36°C were recorded. Thus, despite their effectiveness for smear layer removal, these parameters may not be appropriate for clinical use as an adjunct to conventional periodontal therapy.J Periodontol 1995;66:1032–1039.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1032

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

Periodontal files are used by many dentistsfor instrumentation of root surfaces as a part of periodontal treatment. The purposes of this study were: 1) to examine, evaluate, and compare several periodontal files in 3 different conditions: new, used, and used/sharpened and 2) to evaluate the efficacy of 5 sharpening devices. The main characteristics observed included: the number, shape, and interval of blades; the active, rake, and lip angles; changes induced by wear; the influence of sharpening; and the type of metal surfaces comprising the blades. There was a wide range of active angles on each individual file, from a high of 75° to a low of 51°. The range of active angles for all blades on all new files was even greater, from a high of 87° to a low of 30°. Wear, observed on some but not all blades, was not extensive and appeared either as abrasion or, occasionally, as fracture of the blade edge. Sharpness scores (5 = sharpest and 1 = dullest) for new file blades were also extremely variable and spanned the full range of values, with a majority of blades scoring 3.5 and below. Attempts to sharpen files with several devices produced inconsistent results. All 5 sharpening devices had significant shortcomings. It was concluded that the extreme ranges both in active angles and in sharpness scores probably have a significant influence on effectiveness of root instrumentation.J Periodontol 1995;66:1040–1046.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1040

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

To learn more about the effects of smokeless tobaccoon the defensive functions of neutrophils, we studied the influence of nicotine on these cells in vitro, looking at their bactericidal activity against oral pathogens, and at their ability to produce microbicidal reactive oxygen species (oxygen radicals). Exposure of human blood neutrophils to nicotine (0.01% to 0.1%) inhibited their ability to killActinomyces naeslundii, Actinobacillus actinomycetemcomitans, andFusobacterium nucleatum. Although these concentrations of nicotine are high, such concentrations are relevant to phagocytes in the gingival sulcus, because smokeless tobacco contains 0.5% to 3.5% nicotine by dry weight. Nicotine had no such inhibitory effect when the killing assay was performed in an anaerobic environment, implying that nicotine preferentially affected oxygen‐dependent killing mechanisms. To further investigate the effects of nicotine on production of oxygen radicals, neutrophils were primed with lipopolysaccharide and triggered with f‐met‐leu‐phe or phorbol ester in the presence of nicotine. Nicotine inhibited production of Superoxide anion (measured by reduction of cytochrome c) and hydrogen peroxide (measured by oxidation of phenol red). Nicotine inhibition of Superoxide production was reversible by washing away the nicotine. By observing that nicotine inhibited the reduction of cytochrome c by reagent potassium Superoxide, we determined that nicotine directly absorbed Superoxide. In addition, by examining nicotine inhibition of the uptake of oxygen by neutrophils, we determined that nicotine also interfered with the production of oxygen radicals by these cells. Nicotine also inhibited production of Superoxide and interleukin‐lβby monocytes. Nicotine did not affect the viability of neutrophils and monocytes, as determined by their ability to exclude trypan blue dye. Inhibition of the aerobic antimicrobial functions of neutrophils and monocytes by nicotine may alter the microbial ecology of the oral cavity, and this might be one mechanism by which nicotine compromises the oral health of users of tobacco products.J Periodontol 1995;66:1047–1055.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1047

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

Normal function of gingival fibroblastsis essential for maintenance of the gingival extracellular matrix (ECM), but under inflammatory conditions in gingival tissue which may occur with tobacco use, they can also act in its destruction. The purpose of this study was to determine the effects of nicotine, a major component of tobacco, on gingival fibroblast proliferation, the production of fibronectin (FN), and the production and breakdown of type I collagen to elucidate its role in periodontal destruction associated with its use. A human gingival fibroblast strain derived from a healthy individual with non‐inflamed gingiva was used in this study. Nicotine at concentrations>0.075% caused cell death, and at 0.075% and 0.05% it caused transient vacuolization of the fibroblasts. At concentrations of 0.001% to 0.075%, nicotine significantly inhibited proliferation (P≤ 0.03), measured by the incorporation of [3H]‐thymidine into DNA. The production of FN and type I collagen was significantly inhibited by nicotine at ≥ 0.05% (P≤ 0.001), measured using specific ELISAs. On the other hand, nicotine at ≥ 0.025% significantly increased collagenase activity (P≤ 0.008), using [3H]‐gly and [14C]‐pro‐labeled type I collagen gels as substrate. The results show that, in vitro, nicotine inhibits the growth of gingival fibroblasts and their production of FN and collagen, while also promoting collagen breakdown. This suggests that nicotine itself may augment the destruction of the gingival ECM occurring during periodontal inflammation associated with smokeless tobacco use.J Periodontol 1995;66:1056–1064.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1056

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

Peripheral ameloblastomas are rare odontogenictumors presenting as tumoral masses, erythematous plaques, or papillary lesions on the attached gingiva. This study reviews the demographic, clinical, and microscopic features of 8 previously unreported cases. One patient had two separate peripheral ameloblastomas, one 7 years after the first in the opposite side and arch. The cases match those described previously with respect to age, gender, location, and radiographic and microscopic features. Because recurrence has been reported and second primary sites may be found, periodic followup is recommended after conservative surgical removal.J Periodontol 1995;66:1065–1068.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1065

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

The botryoid odontogenic cystis considered to be a multiloculated variant of the lateral periodontal cyst. Fewer than 40 of these lesions have been described, many of which have recurred. This paper describes the demographic, clinical, microscopic, and radiographic features of 33 unreported cases from the files of the Oral Pathology Biopsy Service at the University of North Carolina School of Dentistry. Our findings are in agreement with previously published cases for an average age of 57 years and the most common site for occurrence in the lower premolar area. Follow‐up information on 12 patients determined that 2 had recurrences.J Periodontol 1995;66:1069–1073.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1069

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

The objective of this studywas to evaluate an allogeneic bone matrix (ABM) as a graft material for the treatment of periodontal osseous defects. ABM is allogeneic demineralized freeze‐dried human bone which has been processed to eliminate contaminating lipids, serum proteins, and cellular components which, when present, have the potential to reduce the osteoinductive capacity of the graft. ABM is provided in a glycerine delivery suspension which enhances graft stability and ease in placement. Paired osseous defects, ranging in depth from 3 to 12 mm, within 11 patients, were randomized to receive ABM or demineralized freeze‐dried bone allograft (DFDBA). Probing depth, clinical attachment level, bone fill, and defect resolution were determined at baseline and at the 6‐month re‐entry procedure. Standardized radiographs and computer‐assisted densitometric image analysis (CADIA) were used to assess bone density changes. Complete bone defect resolution was seen in 7 of 11 defects receiving ABM, and in 5 of 11 defects with the use of DFDBA. Mean defect fill with ABM was 69% (33 to 100%) compared to 77% (66 to 100%) with DFDBA. Soft tissue healing without clinical evidence of tissue reaction to ABM was observed. ABM and DFDBA sites exhibited similar probing depth reduction of 4.0 and 4.6 mm, respectively. In sites with initial probing depth of 7 mm or more, probing depths were reduced a mean of 5.8 mm with ABM and 6.7 mm with DFDBA; both grafts resulted in a mean 4 mm of attachment gain. Results of radiographic analysis suggest similar density changes with each graft. These results demonstrate that both treatments were effective and that ABM may be a useful graft material in the treatment of periodontal osseous defects.J Periodontol 1995;66:1074–1079.

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1074

出版商:Wiley    

年代:1995

数据来源: WILEY

ISSN:1049-8885    

DOI:10.1902/jop.1995.66.12.1080

出版商:Wiley    

年代:1995

数据来源: WILEY