Prevalence of diabetes among patients diagnosed with periodontitis: A retrospective cross-sectional study.

OBJECTIVE: The objective of this study was to assess the prevalence of diabetes among patients with periodontitis and to evaluate whether diabetes is related to extent and severity of periodontitis. METHOD: This is a retrospective study of data observed over a 10-year period in patients referred to a specialized clinic for periodontology in the Netherlands. Patients received at the intake appointment a full-mouth periodontal examination, and based on the clinical data, patients were classified with respect to extent and severity of periodontitis. In addition, the prevalence of diabetes was recorded, based on self-report. RESULTS: A total of 5375 periodontitis patients were included in the study sample (mean age of 50 years). The prevalence of diabetes in this patient sample was 3.7% (n=192). No relation between diabetes and extent or severity of periodontitis could be established. CONCLUSION: The prevalence of diabetes in a predominantly "controlled" diabetic population was not related to the extent and/or severity of periodontitis along with the finding that the prevalence was lower than the national diabetes prevalence in the Netherlands.

Interproximal cervical lesions caused by incorrect flossing technique.

UNLABELLED: This case report describes an interproximal cervical lesion caused by the incorrect use of dental floss. A 58-year-old man who was asymptomatic, presented with unusual notch-like cervical lesions. After clinical and radiographical examinations, it was concluded that the aetiology of these lesions was an incorrect flossing technique. The treatment plan included extraction of maxillary 3rd molars and re-education of the patient in oral hygiene technique. CONCLUSION: These lesions are irreversible and often go undiagnosed; therefore, it is important for the clinician to be familiar with the clinical presentation and aetiology.

Activation of fibroblast procollagenase by mast cell proteases.

Proteases capable of activating procollagenase from gingiva and from fibroblast and macrophage monolayer cultures were harvested from homogenates of canine tumor mast cells. The mast cell proteases lysed casein and Azocoll but not native collagen. In low salt concentrations the enzymes existed at high molecular weight complexes, which were dissociated by increasing the salt concentration above 1.0 M (NaCl, KCl). Gel filtration in 1.4 M KCl separated the protease activity into three peaks, all of which activated procollagenase. Two of the enzymes showed substrate specificities (hydrolysis of p-tosyl-L-arginine methyl ester and benzoyl-tyrosine ethyl ester) and reactive center reactivities similar to pancreatic trypsin and chymotrypsin. Based on gel filtration, apparent molecular weights of 160 000 (p-tosyl-L-arginine methyl ester esterase), 90 000 (main procollagenase activator) and 36 000 benzoyl-tyrosine ethyl ester esterase) were determined. Activation of procollagenase resulted in a 18-20 000 decrease of the molecular weight. The activation was directly related to the amount of activator added within certain limits. Further addition of activator resulted in proteolytic inactivation of collagenase.

Procollagenase from bovine gingiva.

1. Collagenase (EC 3.4.24.3) is released from bovine gingival explants in vitro as a zymogen. The zymogen does not hydrolyze collagen and does not form a complex with alpha2-macroglobulin (alpha2-M). It elutes in gel filtration with an apparent molecular weight of approx. 80 000. 2. Incubation of the zymogen with trypsin results in a 15 000-20 000 dalton decrease in molecular weight and imparts to the enzyme the ability to hydrolyze collagen and to form a complex with alppha2-M. 3. The zymogen can be completely separated from the active enzyme to alpha2-M. Likewise, the zymogen can be harvested from cultures supplemented with serum.

Chemical characterization of lased root surfaces using Fourier transform infrared photoacoustic spectroscopy.

Recently lasers have been recommended as an alternative or adjunctive therapy in the control and treatment of periodontally diseased root surfaces. The purpose of this in vitro investigation was to characterize the chemical structure of lased root surfaces using Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). Cementum samples, 6 mm x 2 mm, were cut from the root surface of extracted non-carious, unerupted human molars. The experimental samples were lased with a Nd:YAG laser at an average energy of 80 mJ at 10 pulses per second. Total lasing time ranged from 1 minute 45 seconds to 4 minutes. A non-lased cementum sample served as the control. All spectra were recorded from 4000 to 400 cm-1 using the photoacoustic cell attachment on an Analect RFX-65 FTIR Spectrometer. Photoacoustic FTIR spectra of lased cementum samples showed a decrease in the protein/mineral ratio in comparison to the control. Breakdown of protein at the root surface potentially contributed to an ammonium band at 2010 cm-1. The decreased protein/mineral ratio and the potential surface contamination with protein by-products, may ultimately affect cell reattachment at the cementum surface.

Tissue concentration and localization of tetracycline following site-specific tetracycline fiber therapy.

The primary objective of this study was to evaluate the concentration and location of tetracycline hydrochloride in tissue adjacent to periodontal pockets treated with a tetracycline impregnated fiber. A secondary objective was to determine if the presurgical placement of fibers had any adverse effects on healing following periodontal surgery. The study population consisted of 10 patients with at least 2 pockets in both maxillary quadrants of > or = 5 mm in depth and exhibiting bleeding on probing. After an initial scaling and root planing, placebo or tetracycline fibers were randomly assigned by quadrant to 2 non-adjacent pockets. Fibers were removed at the time of surgery; i.e., day 8, and periodontal surgery was performed utilizing a flap incision that allowed biopsy of 1 interdental papilla from each of the 2 test sites in each quadrant. One biopsy was analyzed for tetracycline concentrations by high performance liquid chromatography (HPLC). The second biopsy was examined by both light and ultraviolet fluorescence microscopy to determine the location of residual tetracycline and the intensity of inflammatory cell infiltrates. Results showed that the tissue concentration of the antibiotic in tetracycline treated sites was 64.4 +/- 7.01 ng/mg (ng of tetracycline/mg tissue weight) which corresponds to 43 micrograms of tetracycline and was below levels of accurate measurement in placebo treated sites. Tetracycline tissue concentrations corresponded to the ultraviolet fluorescence microscopy with a Pearson correlation coefficient of r = 0.92. Tetracycline fluorescence was noted in the soft tissue wall ranging from 1 to 20 microns.(ABSTRACT TRUNCATED AT 250 WORDS)

Microscopic characterization of root surface-associated microbial plaque in localized juvenile periodontitis.

The purpose of this investigation was to characterize by scanning electron microscopy, the microbial morphotypes associated with the roots of teeth from patients exhibiting localized juvenile periodontitis (LJP). Eighteen teeth were examined from 10 adolescent patients who satisfied the standard clinical diagnostic criteria for LJP. The microscopic evaluation was facilitated by dividing that portion of the root exposed to the periodontal pocket into coronal, middle, and apical one-thirds. Controls consisted of an equal number of teeth matched as to pocket depth and anatomical type obtained from patients exhibiting adult periodontitis (AP). All specimens were coded and examiners were unaware of their origins. Results of the SEM evaluation revealed little difference in microbial morphotypes comprising the root associated plaque in the coronal one-third of LJP specimens when compared to the AP controls. The dominant microbial morphotypes were cocci, short and long rods, filamentous microorganisms, and spirochetes. However, microbial plaque located in the middle and apical one-third root zones of LJP specimens was distinctly different than that of AP specimens. In the deeper pocket zones the dominant microbial morphotypes in LJP specimens were limited to cocci, short rods, coccobacilli, and various sized spirochetes. In contrast, AP specimens exhibited a collection of microbial morphotypes consisting of cocci, short rods, long rods, filamentous organisms and spirochetes. Calculus was found on the root surfaces of all specimens regardless of disease category although, as a group, the LJP specimens featured lesser amounts. Although areas of root resorption were common in both LJP and AP groups, they were more frequently observed in LJP specimens, likely associated with the generally less confluent deposits of calculus and plaque.

Ultrastructural examination of human periodontal pockets following the use of an oral irrigation device in vivo.

To date, there are no ultrastructural studies that have examined untreated chronic periodontal pockets immediately following dental debridement with an oral irrigation device. This study used both scanning electron microscopic and transmission electron microscopic methodology to examine previously untreated human periodontal pockets after their exposure to a pulsating oral irrigation with saline solution. A comparison of 16 untreated controls with 16 test specimens revealed qualitative differences in microbial morphotypes at various pocket depths. Control specimens at all pocket depths examined (0-6 mm), exhibited a mixed microbial flora consisting of cocci, short rods, and filamentous organisms. Specifically at 3- to 4-mm and 5- to 6-mm levels in control specimens, spirochetes, fusiforms, and branching organisms were obvious. In contrast, test specimens exhibited a few cocci and short rods at 0- to 2-mm and 3- to 4-mm levels and a mixed flora at the 5- to 6-mm level. There was no observable difference between control and test specimens concerning epithelial topography, cavitations, microulcerations, spatial relationships, and individual cell appearance. Both control and test specimens exhibited a mild spirochete invasion of the epithelial strata. Collectively these observations suggest that pulsating oral irrigation effects a qualitative change on subgingival plaque and is not injurious to the soft tissues.

A preliminary study on the effects of the Nd:YAG laser on root surfaces and subgingival microflora in vivo.

The purpose of this study was to examine the effects of root preparation using the pulsed Nd:YAG laser, either alone or in combination with manual instrumentation. Study specimens consisting of 18 teeth with associated periodontal pockets from 8 different patients were treated as follows: 5 specimens were root planed with curets followed by laser exposure for 3 minutes using energy settings of 3.0 W at 20 pps; 2 specimens were root planed and then laser treated for 3 minutes using settings of 2.25 W and 20 pps; 4 specimens were treated by laser for 1 minute at settings of 1.75 W and 20 pps followed by root planing; 4 specimens were treated by laser only for 1 minute using settings of 1.75 W and 20 pps; and the remaining 3 teeth served as untreated controls. Both prior to and after completion of the laser and root planing treatments, microbiological samples were obtained from the treated pockets and submitted to a commercial laboratory for analysis of levels of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia. With the exception of two 7-day specimens, all others were extracted immediately post-therapy and processed for SEM examination. All treated specimens, regardless of treatment sequence, exhibited some degree of laser-induced root surface alteration. Notably, laser-treated calculus deposits were free of their characteristic surface layer of microbial plaque. Microbial sampling indicated a post-therapy reduction in levels of all 3 putative microbial pathogens compared to pre-treatment samples and control specimens. However, SEM examination revealed residual deposits of plaque and calculus in all treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute necrotizing ulcerative gingivitis. A transmission electron microscope study.

The purpose of this study was to provide additional evidence that in the lesions of acute necrotizing ulcerative gingivitis (ANUG), spirochetes and other microorganisms are capable of invading the nonnecrotic lamina propria of affected gingivae. Biopsies from eight patients with pathognomonic signs of ANUG were obtained under local anesthesia and processed for light and transmission electron microscopy. The results indicated that spirochetes and other bacteria are capable of penetrating the viable connective tissues of the lamina propria. The four zones of the ANUG lesion as first described by Listgarten were observed without difficulty. The maximum depth of bacterial infiltration into the lamina propria ranged from 155 to 400 microns from the nearest epithelial basal lamina. The histologic picture of the ANUG lesion did not always conform to the acute clinical manifestations.

Connective tissue attachment to periodontally diseased roots after citric acid demineralization.

PREVIOUS INVESTIGATIONS have demonstrated that application of citric acid to a root surface results in exposure of dentin and/or cementum matrix collagen fibrils. Several studies have suggested a rapid and consistent connective tissue reattachment to citric acid treated roots. This study was initiated to determine if such an attachment was obtainable on human periodontally diseased teeth, in vivo, and could be confirmed through observations using the scanning electron and light microscopes. Full thickness flaps were raised on 18 single rooted teeth with moderate to advanced periodontitis. Citric acid (pH = 1.0) was applied to nine teeth with contralateral teeth serving as controls. Six to fifteen weeks later, the teeth with attached periodontal tissue were removed. Sagittal sections were obtained, with one-half of the root being processed for light microscopy and the remaining half studied by scanning electron microscopy. Six of nine citric acid treated roots provided evidence of fibrous attachment. Connective tissue was apposed directly to old or newly formed cementum, but never directly to dentin. Fibrous attachment was usually functionally oriented, i.e., perpendicular to the root surface. No evidence of fibrous attachment was found among the control specimens.

The effect of an air-powder abrasive system on in vitro root surfaces.

An air-powder abrasive system, the Prophy-Jet model C-100, is now available for use by the dental community. However, its use has been restricted to cleaning enamel surfaces of stain and dental plaque. The purpose of this investigation was to ascertain the effects of this air-powder abrasive system on root surfaces of extracted human teeth. Thus, root surfaces of 20 teeth were covered with a template consisting of a metal band with a centrally located 2-mm diameter hole. The banded root surfaces, under controlled conditions, were exposed to the air-powder abrasive for 30 seconds. The resulting defects were measured by using a light microscope equipped with a graduated focus knob. Three teeth were randomly selected for examination by scanning electron microscopy and one was selected for histologic evaluation by light microscopy. Untreated extracted teeth were used as controls. In addition, one untreated tooth root was exposed to the air-powder abrasive without use of the template. In this instance, a brush stroke was used for approximately 1 minute, as might be done in a clinical situation. This tooth root was also examined by scanning electron microscopy. The Prophy-Jet air-powder abrasive system removed an average of 636.6 micrometers of root structure in 30 seconds of exposure time. The resulting surface was smooth, free of connective tissue fibers and debris, and all cementum was removed. Few open dentin tubules were observed since most appeared to have been obliterated. The powder crystals, as viewed by scanning electron microscopy, were sharp-pointed, somewhat elongated and of varying lengths. The Prophy-Jet air-powder abrasive system appears to have considerable potential for treatment of periodontally diseased root surfaces. However, its use should be tempered by the results of this and future research and sound clinical judgment.

The effect of 2% chlorhexidine digluconate irrigation on clinical parameters and the level of Bacteroides gingivalis in periodontal pockets.

Eight patients with moderate periodontitis volunteered to participate in a study to assess the effect of subgingival 2% chlorhexidine irrigation, with and without scaling and root planing, on clinical parameters and the level of Bacteroides gingivalis in periodontal pockets. Each quadrant was required to have at least one site with a probing depth of 6 mm or greater and bleeding on probing. The patients were treated following a randomized four quadrant design: one quadrant received no treatment; a second quadrant received scaling and root planing only; a third quadrant received chlorhexidine irrigation only; the fourth quadrant received scaling and root planing, plus chlorhexidine irrigation. Sites to receive chlorhexidine were irrigated at 0, 1, 2, and 3 weeks. Clinical and microbiological indices were measured and recorded at 0, 5, 7, 11, and 15 weeks. The clinical parameters measured included; Plaque Index (PI), Gingival Index (GI), probing depth (PD), Bleeding Tendency (BT), and attachment level (AL). The attachment level was measured using an occlusal stint as a fixed reference point. The level of Bacteroides gingivalis was measured by labeling the plaque sample with a polyclonal fluorescent antibody. The plaque smear was then read using a fluorescent microscope at 1000 magnification. The Spearman Rank-Order Correlation was used to determine the relationship between parameters at baseline. The effects of the treatment groups were compared using the Neuman-Keuls Multiple Comparison Technique. The results showed that a positive correlation existed between B. gingivalis (rs = 0.68) and Bleeding Tendency and between P1I (rs = 0.77) and GI.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of the Nd:YAG laser on in vitro fibroblast attachment to endotoxin-treated root surfaces.

The purpose of this study was to evaluate the effects of the Nd:YAG laser on in vitro fibroblast attachment to endotoxin-treated root surfaces and to describe any laser-induced cementum surface alterations. Thirty 4 mm x 4 mm cementum segments were obtained from unerupted third molars. The treatment groups were as follows: 1) control, healthy root segment; 2) non-lased, endotoxin treated; and 3) lased, endotoxin treated. The endotoxin treated roots were soaked in E. coli 055:B5 lipopolysaccharide (556 EU/ml) for 72 hours. The lased, endotoxin-treated root segments were treated with a Nd:YAG laser using a 320 microns contact optic fiber handpiece with an energy setting of 80 mJ at 10 pulses per second for one minute. The root segments were subsequently placed in fibroblast culture dishes for 40 hours and then prepared for scanning electron microscopy (SEM) observation. SEM examination revealed two different types of attachment: flat and round. Flat cells represented firmly attached cells due to well-defined points of attachment and numerous lamellapodia. Round cells possessed few attachment processes and were, therefore, considered poorly attached. The lased, endotoxin-treated root segments had significantly decreased numbers of flat fibroblasts versus the control and non-lased, endotoxin-treated root segments. The absence of flat fibroblasts in the laser treated root segments was a consistent finding. The non-lased, endotoxin-treated root segments had significantly increased numbers of round fibroblasts versus the control and lased, endotoxin treated groups. The lased root segments exhibited surface alterations which included charring, crater formation, cementum meltdown, and tracking.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of Nd:YAG laser exposure on root surfaces when used as an adjunct to root planing: an in vitro study.

The purpose of this study was to evaluate the effects of Nd:YAG laser treatment on root surfaces in vitro when used alone or in combination with conventional scaling and root planing. The study population consisted of 18 unerupted third molars, each with a 3 mm diameter treatment site outlined on the root surface. Three specimens were randomly assigned to each of 6 different treatment groups: 1) untreated control; 2) root planed only; 3) laser treated only using 1.25 W of energy; 4) laser treated only using 1.50 W of energy; 5) laser treated with 1.25 W of energy followed by root planing; and 6) laser treated with 1.50 W of energy followed by root planing. Following their respective treatment, all specimens were prepared for evaluation by scanning electron microscopy. Specimens from Group 2, root planed only, exhibited a smear layer of scale-like texture with parallel instrument tracks resulting from curet use. Specimens treated by laser only, Groups 3 and 4, featured various surface changes not observed in controls such as charring and carbonization of the cementum surface, randomly distributed pitting and crater formation, and melting of the root mineral phase with subsequent resolidification as porous globules. Those specimens treated by laser followed by root planing, Groups 5 and 6, exhibited surface characteristics similar to those noted in Group 2 specimens. Further, there were areas of exposed dentinal tubules resulting from a "peeling" of the cementum layer. The results of this in vitro study suggest that laser use during root preparation, even at relatively low energy levels, will result in physical changes to the root surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Root surface characteristics associated with subgingival placement of monolithic tetracycline-impregnated fibers.

The purpose of this investigation was to inspect and characterize the subgingival root surface after a 10-day exposure in vivo to 25% tetracycline hydrochloride by weight in an ethylene vinyl acetate copolymer fiber matrix with and without root planing therapy. The root surfaces were examined by fluorescent-light microscopy (FLM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Thirty-two teeth were selected for study, 4 from each of 8 patients. The teeth of each patient were randomly assigned to one of four treatment groups: non-treated control (C), scaling and root planing only (RP), tetracycline-impregnated fiber only (F), and scaling and root planing with tetracycline-impregnated fiber application (RP/F). SEM revealed a visible reduction in the subgingival microbial flora in both the F and RP/F treatment groups in comparison with the C group specimens. Many of the residual bacteria observed in F and RP/F specimens appeared non-viable, exhibiting obvious loss of membrane integrity. In contrast, the RP specimens exhibited randomly distributed areas of residual subgingival plaque and calculus with newly developing plaque fronts; the plaque fronts undoubtedly having formed during the 10 days post-therapy. All RP/F specimens exhibited an incomplete removal of adsorbed root surface pellicle and demineralization of the subsequently exposed root surface. EDS analysis of large crystals adhering to root surfaces of F and RP/F specimens revealed high chloride peaks, suggesting the presence of residual tetracycline. FLM examination of F and RP/F treated specimens showed a superficial penetration of tetracycline into the root surface of about 10 microns. Areas of demineralized root showed slight tetracycline penetration into exposed dentinal tubules.

Laser irradiation of bone: III. Long-term healing following treatment by CO2 and Nd:YAG lasers.

BACKGROUND: Relative few reports exist concerning healing of laser created osteotomies over an extended period of time. The purpose of this study was to evaluate long-term healing, from 21 to 63 days, of osteotomy defects in the rat tibia created with the Nd:YAG and CO2 in the presence of a surface cooling spray of air/water. METHODS: The experimental model consisted of 15 large Sprague-Dawley rats. Six treatment modalities were randomly distributed among 6 tibial recipient sites: 1) a negative control (no treatment); 2) a positive control (bur osteotomy); 3) CO2 laser at 5 W (860 J/cm2); 4) CO2 laser at 6 W (1,032 J/cm2); 5) Nd:YAG laser at 5 W (714 J/cm2); and 6) Nd:YAG laser at 7 W (1,000 J/cm2). All laser irradiation was delivered in the presence of a surface coolant consisting of air (15 psi) and sterile water. Five animals were sacrificed at each of 3 time intervals: 21, 35, and 63 days post-treatment. Multiple histologic sections from each treatment site were examined by light microscopy using hematoxylin and eosin Goldner's trichrome stains, and polarized light and evaluated for presence of a char layer, heat induced cracking, heat related alterations in cells or tissue matrix, and osseous regeneration. RESULTS: Healing was severely delayed in all laser treated sites compared to positive control sites. Of the laser treated sites, those irradiated by CO2 laser at 5 W (780 J/cm2) exhibited the greater amount of bone regeneration. At best, however, only a small percentage of sections from any of the laser treated specimens showed evidence of bone regeneration within the ablation defect regardless of the post-treatment time interval. CONCLUSIONS: Under the conditions of this study, the osseous healing response was severely delayed by CO2 and Nd:YAG laser irradiation of bone, even in the presence of a surface cooling spray of air/water.

In vitro chemotactic response of osteoblast-like osteosarcoma cells to a partially purified protein extract of demineralized bone matrix.

The purpose of this investigation was to evaluate the chemotactic potential of a partially purified protein extract from bone matrix when tested against osteosarcoma cells with osteoblast characteristics. The chemotactic response of ROS 17/2 cells to a lyophilized bovine bone extract purified to "Urist step eight" was evaluated in Boyden blind well chambers. A checkerboard design was employed to test cell migration against positive, negative, and no concentration gradients, thereby controlling the effects of chemokinesis and/or random migration on results. The results demonstrate that the partially purified protein extract from bovine bone matrix is chemotactic since more cells migrated to positive gradients than to negative gradients (P less than .01). The chemotactic effect was confirmed by an increase in cell migration toward positive gradients of the bone extract compared to cell migration in the presence of no gradient (P less than .01). When no gradient was present, the cells exhibited an increased response in the presence of equal concentrations of the bone extract (P less than .01) indicating a chemokinetic effect. The proteinaceous nature of the chemoattractant was confirmed by its susceptibility to trypsin digestion and heat exposure.

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.

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.