bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparative Scanning Electron Microscopic Study on the Characteristics of Demineralized Dentin Root Surface Using Different Tetracycline HCl Concentrations and Application Times
Authors: Isik A. Gülden , Tarim Berna , Hafez Abeer A. , Yalçin Funda Sağlam , Onan Utku , Cox Charles F. 
Published: February 2005

Background: The use of demineralizing agents has been reported to enhance the degree of connective tissue attachment to denuded roots. Of the agents used, tetracycline HCl has received the most attention.Methods: The purpose of this study was to evaluate and compare the SEM surface morphology of human root dentin following various concentrations and application times of tetracycline HCl. The surface characteristics were compared and the width of dentin tubule orifices were measured and analyzed. Twelve human teeth were collected and stored in distilled water after soft tissue removal using hand instruments. The apical third of each root was removed and remaining mid‐root region was sectioned longitudinally through the root canal following removal of its cementum with a fine diamond bur. A total of 48 dentin specimens were randomly divided into 8 groups for conditioning at different tetracycline HCl concentrations, at 0, 10, 25, 50, 75, 100, 125, and 150 mg/ml. Application times for each group were 1, 3, and 5 minutes. Immediately following treatment procedures, the specimens were rinsed, fixed in GTAPBF, dehydrated, and prepared for SEM. Each specimen was examined at 2 magnification values, representative fields photographed, and data tested by one‐way ANOVA and paired t test statistical analysis.Results: Our results indicate that the use of tetracycline HCl solution between 50 mg/ml and 150 mg/ml showed a statistically significant opening of dentin tubules. All tetracycline HCl groups at 1, 3, and 5 minutes show smear layer removal from the dentin surface.Conclusions: Dentin demineralization is not time dependent at all concentrations of tetracycline HCI. J Periodontol 2000;71:219‐225.
Guided Tissue Regeneration With a Bioabsorbable Polylactic Acid Membrane in Gingival Recessions. A Histometric Study in Dogs
Authors: Casati Marcio Z. , Sallum Enilson A. , Caffesse Raul G. , Nociti Francisco H. , Sallum Antonio Wilson , da Silva Pereira Sergio L. 
Published: February 2005

Background: The goal of this investigation was to histologically and histometrically evaluate the healing process of gingival recessions treated by guided tissue regeneration with bioabsorbable polylactic acid membranes (GTR group) and to compare it to that obtained with coronally positioned flaps (CPF group).Methods: Gingival recessions were surgically created on the buccal aspect of the upper cuspids of 5 mongrel dogs. The defects (5×7 mm) were exposed to plaque accumulation for 3 months. The contralateral defects were then randomly assigned to each group. After 3 months of healing, the dogs were sacrificed and the blocks were processed. The histometric parameters evaluated included length of sulcular and junctional epithelium, connective tissue adaptation, new cementum, new bone, and defect coverage.Results: The extension of the epithelium was 1.9 ± 0.8 mm for the GTR‐group and 3.0 ± 0.9 mm for the CPF‐group (P = 0.16). The connective tissue adaptation was 0.1 ± 0.1 and 0.8 ± 0.5 mm in the GTR group and CPF group, respectively (P = 0.051). The new cementum was 3.8 ± 1.5 mm and 2.4 ± 0.3 mm in the GTR group and CPF group, respectively (P = 0.16). Bone formation was 1.1 ± 0.5 mm in the GTR group and 1.4 ± 0.2 mm in the CPF group (P = 0.53). Histologically, the defect coverage observed was similar, 90.5% and 91.9% for the GTR group and the CPF group, respectively. No statistical differences in any of the parameters could be detected.Conclusions: Within the limits of this study, it can be concluded that both procedures resulted in a favorable healing response with no significant difference between the treatments. J Periodontol 2000;71:238‐248.
Periodontopathic Bacteria in Children With Down Syndrome
Authors: Amano Atsuo , Kishima Tetsuhiko , Kimura Shigenobu , Takiguchi Miyako , Ooshima Takashi , Hamada Shigeyuki , Morisaki Ichijiro 
Published: February 2005

Background: It is widely known that individuals with Down syndrome (DS) often develop severe early‐onset periodontal diseases. In this study, we examined the prevalence of periodontopathic bacteria in DS children to determine if specific pathogens are acquired in their childhood.Methods: The subjects were 60 DS children (2 to 13 years old, 5 in each age bracket) and 60 age‐matched controls. Ten pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Treponema denticola, Prevotella intermedia, P. nigrescens, Capnocytophaga ochracea, C. sputigena, Campyrobacter rectus, and Eikenella corrodens were surveyed in subgingival plaque samples using a polymerase chain reaction. Periodontal status was evaluated by probing depth, bleeding on probing, and gingival index.Results: No significant difference in periodontal status was observed between the DS and control groups, however, all of the pathogens were detected with greater frequency in the DS children. B. forsythus, T. denticola, P. nigrescens, and C. rectus were significantly prevalent throughout all age brackets of the DS children (P <0.01 or 0.05). The occurrence of P. gingivalis was also significant in the DS subjects over 5 years old. A cluster analysis of the microbial profiles of the DS subjects showed that gingivitis severity was associated with increased varieties of the harboring pathogens and the distribution of P. gingivalis.Conclusions: These results suggest that various periodontopathogens can colonize in the very early childhood of DS patients and maturation of subgingival components, including P. gingivalis, plays an important role in the initiation of gingival inflammation. J Periodontol 2000;71:249‐255.
The Effect of Chlorhexidine Mouthrinses on Early Bacterial Colonization of Guided Tissue Regeneration Membranes. An In Vivo Study
Authors: Zucchelli G. , Pollini F. , Clauser C. , De Sanctis M. 
Published: February 2005

Background: Different membrane materials accumulate varying amounts of bacteria when exposed in the oral cavity, due to their textural and structural surface characteristics. The aim of the study was to evaluate the effect of chlorhexidine mouthrinses on the in vivo early bacterial colonization of 3 different guided tissue regeneration membrane materials.Methods: Rectangular‐shaped strips cut from 3 periodontal membranes (expanded polytetrafluoroethylene, polyglactin 910, and polylactic acid) were glued to removable devices adapted to the 2 upper quadrants in 8 dental students. In each student 1 quadrant was randomly selected as test side while the other served as control side. The experiment was divided in 2 phases: in the first phase plaque accumulation was followed for 4 hours while the second accumuation was followed for 24 hours. During the 4‐hour experiment, students rinsed the test device twice (immediately following device application and after 2 hours) with 0.12% chlorhexidine solution. The control device was rinsed with saline. In the second phase, students rinsed the test device with chlorhexidine and the control devices with saline 3 times (after device application and at 8 and 16 hours). Both the 4‐hour and the 24‐hour specimens were processed for scanning electron microscopy analysis. Fifty‐four fields (at 200× magnification) were randomly selected and analyzed on each strip. Magnification was increased to determine the presence and morphotype of bacteria. The presence or absence of bacteria was assessed in a binomial fashion: the field was bacteria‐positive when bacteria constituted the deposits covering the membrane surface. The microscopic field was negative (bacterianegative) when no bacteria were observed. Bacteria‐positive fields showing rods and filaments as prevalent morphotypes were recorded as rod‐positive fields.Results: The results of data analysis suggest that bacterial contamination of membrane materials is significantly reduced by treatment with chlorhexidine. They also suggest that other variables affect plaque accumulation as well; i.e., the time allowed (4 versus 24 hours) and the different membrane materials. The interaction between these 2 variables is also highly significant, thereby indicating a different rate of plaque accumulation on different materials, irrespective of the treatment with chlorhexidine.Conclusions: It was concluded that chlorhexidine mouthrinses may be effective in reducing and delaying the early bacterial accumulation on membrane materials although they are not able to fully prevent it. Membrane surface characteristics seem to be a more critical factor than the use of chlorhexidine, in influencing bacterial adhesion and colonization of barrier materials. J Periodontol 2000;71:263‐271.
A Histochemical Investigation of the Bone Formation Process by Guided Bone Regeneration in Rat Jaws. Effect of PTFE Membrane Application Periods on Newly Formed Bone
Authors: Ohnishi Hideo , Fujii Noritaka , Futami Takayuki , Taguchi Naoyuki , Kusakari Haruka , Maeda Takeyasu 
Published: February 2005

Background: Guided bone regeneration (GBR) has been widely utilized for the promotion of bone augmentation in bone loss areas. However, little information has been available regarding chronological changes in newly formed bone and alterations in the nature of newly formed bone after removal of a barrier membrane. The present study attempted to establish a GBR model for rat maxillae. We also examined the effects of membrane application periods on newly formed bone and its remodeling process after removal of the membrane in this experimental model.Methods: Thirty‐five Wistar rats were divided into 2 groups: a membrane application group and a membrane removal group. The chronological changes of newly formed bone were evaluated histologically and statistically.Results: At 2 weeks after the GBR procedure, bony cavities had completely filled the newly formed bone in the experimental side. In the control side, corticalization on the surface of the newly formed bone proceeded with a decrease in the bone marrow cavity, whereas the bone marrow space had enlarged by 12 weeks post‐surgery in the experimental side. In the membrane removal group, the osteoblasts appeared on newly formed bone at 1 week after membrane removal. Comparatively thick compact bone had formed on the surface of the newly formed bone at 4 weeks after membrane removal, and corticalization proceeded later.Conclusions: The long‐term application of a barrier membrane induces the enlargement of the bone marrow spaces. We suggest that PTFE membrane removal in adequate time promotes the corticalization and maturation of the newly formed bone by the GBR technique. J Periodontol 2000;71:341‐352.
The Relationship Between Gingivitis and Colonization by Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in Children
Authors: Morinushi Takanobu , Lopatin Dennis E. , Van Poperin Neal , Ueda Yasuhiro 
Published: February 2005

Background: Porphyromonas gingivalis and actinomycetemcomitans are closely associated with the onset and severity of adult periodontal disease. However, little is known regarding the colonization by, and host antibody response to, these microorganisms in children.Methods: Plaque and sera were obtained from 40 healthy children, 2 to 18 years old. Gingival health was assessed by the periodontal disease index (PDI), papillary bleeding score (BS) and the modified total papillary margin attachment index (M‐PMA). P. gingivalis and A. actinomycetemcomitans in plaque samples were detected by slot immunoblotting (SIB). Serum antibody levels against these microorganisms were evaluated using ELISA.Results: More than 60% of the children had detectable levels of P. gingivalis in their plaque. Those having detectable levels had more gingival inflammation than those having none; however, these differences were significant only in children over the age of 12 years (PDI, BS). In contrast, while 75% of the children had detectable A. actinomycetemcomitans, there were significant differences in gingival inflammation associated with colonization in children from 3 to 7 years of age (PDI) and over 12 years of age (M‐PMA). Serum antibody levels to P. gingivalis were inversely correlated with gingival inflammation in all age groups, while A. actinomycetemcomitans titers were positively correlated with gingival inflammation only in the children over 12 years. No significant relationship between the presence of either A. actinomycetemcomitans or P. gingivalis and antibodies to them was found.Conclusions: Our findings show that P. gingivalis and A. actinomycetemcomitans are readily detected as early as 3 years of age and that their presence is associated with the onset and severity of gingivitis. J Periodontol 2000;71:403‐409.
The Immune Modulation of B‐Cell Responses by Porphyromonas gingivalis and Interleukin‐10
Authors: Champaiboon Chantrakorn , Yongvanitchit Kosol , Pichyangkul Sathit , Mahanonda Rangsini 
Published: February 2005

Background: Polyclonal B‐cell activation induced by periodontopathic bacteria has been cited as being important for elevated numbers of B cells, but the role of bacteria in the pathogenesis of periodontal disease remains unknown. In this study, we used an in vitro model to investigate the activation of immune cells by the periodontopathic bacterium Porphyromonas gingivalis in healthy subjects.Methods: Peripheral blood mononuclear cells (PBMC) or purified subsets of lymphocytes were stimulated with sonicated extracts of P. gingivalis for 24 hours. Cells were harvested and monitored for expression of CD69 by flow cytometry. Cytokine production (IL‐10, IL‐12, and IL‐15) in P. gingivalis‐stimulated PBMC cultures was measured by ELISA. To identify IL‐10 producer cells, a cell depletion experiment was used and confirmed by the ability of the purified cell population to produce IL‐10. To evaluate the effect of P. gingivalis and IL‐10, the proliferative response of purified B cells was assessed by [3H] thymidine uptake.Results: PBMC cultured with P. gingivalis led to a large number of activated B and natural killer (NK) cells as monitored by CD69 expression. When positively sorted cells were used, the bacterium itself could directly activate only B cells but not NK cells, αβ, and γδ T cells. Measurement of B‐cell regulatory cytokine production in P. gingivalis‐stimulated PBMC cultures revealed a large amount of IL‐10 but no detectable IL‐12 or IL‐15; the major producing cells were monocytes, not B cells orαβ T cells. When IL‐10 was added to B cells in the presence of bacteria, significantly increased B‐cell proliferative responses were observed.Conclusions: These results suggest that P. gingivalis, both directly and indirectly via macrophage IL‐10, may play an important role in polyclonal B‐cell activation associated with periodontal disease. J Periodontol 2000;71:468‐475.
Cyclic Tension Force Activates Nitric Oxide Production in Cultured Human Periodontal Ligament Cells
Authors: Kikuiri Takashi , Hasegawa Tomokazu , Yoshimura Yoshitaka , Shirakawa Tetsuo , Oguchi Haruhisa 
Published: February 2005

Background: Nitric oxide (NO) is involved in a number of physiological and pathophysiological processes. The aim of this study was to examine the ability of human periodontal ligament (PDL) cells to produce NO and whether mechanical forces could induce NO production in the PDL cells.Methods: Human PDL cells were seeded onto flexible bottoms of a culture plate and subjected to cyclic tension forces. NO production was evaluated by measuring concentration of NO2‐ and NO3‐ (NO2‐/NO3‐), the oxidized products of NO, in the culture medium. We employed reverse transcription polymerase chain reaction (RT‐PCR) methods to detect NO synthase mRNA in the PDL cells. NO synthase immunoreactivity was also evaluated in both stimulated and unstimulated PDL cells.Results: In unstimulated PDL cell culture, NO2‐/NO3‐increased to 140% of the initial value in 12 hours. In contrast, NO2‐/NO3‐ showed a 3‐fold increase when the cells had been subjected to cyclic tension forces for 12 hours. The increase in NO production was blocked by NG‐monomethyl‐L‐arginine (5 × 10‐4 M), an inhibitor of NO synthase. Endothelial NO synthase (ecNOS) mRNA was expressed in both stimulated and unstimulated PDL cells, whereas inducible NO synthase (iNOS) mRNA was detected in neither culturing condition. We found strong ecNOS but not iNOS immunoreactivity in the stimulated PDL cells.Conclusions: These results suggest that human PDL cells produce NO by ecNOS and that the production is enhanced by stimulating the cells with cyclic tension forces. Mechanically stimulated PDL cells may modulate the function of periodontium by the upregulated NO production. J Periodontol 2000;71:533‐539.
The Effect of Inter‐Implant Distance on the Height of Inter‐Implant Bone Crest
Authors: Tarnow D.P. , Cho S.C. , Wallace S.S. 
Published: February 2005

Background: The biologic width around implants has been well documented in the literature. Once an implant is uncovered, vertical bone loss of 1.5 to 2 mm is evidenced apical to the newly established implant‐abutment interface. The purpose of this study was to evaluate the lateral dimension of the bone loss at the implant‐abutment interface and to determine if this lateral dimension has an effect on the height of the crest of bone between adjacent implants separated by different distances.Methods: Radiographic measurements were taken in 36 patients who had 2 adjacent implants present. Lateral bone loss was measured from the crest of bone to the implant surface. In addition, the crestal bone loss was also measured from a line drawn between the tops of the adjacent implants. The data were divided into 2 groups, based on the inter‐implant distance at the implant shoulder.Results: The results demonstrated that the lateral bone loss was 1.34 mm from the mesial implant shoulder and 1.40 mm from the distal implant shoulder between the adjacent implants. In addition, the crestal bone loss for implants with a greater than 3 mm distance between them was 0.45 mm, while the implants that had a distance of 3 mm or less between them had a crestal bone loss of 1.04 mm.Conclusions: This study demonstrates that there is a lateral component to the bone loss around implants in addition to the more commonly discussed vertical component. The clinical significance of this phenomenon is that the increased crestal bone loss would result in an increase in the distance between the base of the contact point of the adjacent crowns and the crest of bone. This could determine whether the papilla was present or absent between 2 implants as has previously been reported between 2 teeth. Selective utilization of implants with a smaller diameter at the implant‐abutment interface may be beneficial when multiple implants are to be placed in the esthetic zone so that a minimum of 3 mm of bone can be retained between them at the implant‐abutment level. J Periodontol 2000;71:546‐549.
Pocket Oxygen Tension in Smokers and Non‐Smokers With Periodontal Disease
Authors: Hanioka Takashi , Tanaka Muneo , Takaya Keiko , Matsumori Yukiko , Shizukuishi Satoshi 
Published: February 2005

Background: Smoking is associated with destructive periodontal disease. Pocket oxygen tension (pO2) is likely to be a major environmental determinant of the subgingival microflora, which is a primary etiological factor of the disease. This study aimed to compare the pocket pO2 in smokers and non‐smokers with periodontal disease.Methods: Pocket oxygen tension was compared in 27 smokers and 34 non‐smokers by considering 2 confounding factors, probing depth and oxygen saturation of hemoglobin (So2), in the gingiva. The pO2 was determined using oxygen microelectrode by polarographic method with an electronic compensation circuit for subgingival temperature. Gingival So2 was determined using tissue reflectance spectrophotometry.Results: No significant difference was found in the modified gingival index and the plaque index between smokers and non‐smokers. The pO2 was significantly lower in smokers (21.9± 9.6 mmHg) than in non‐smokers (33.4 ± 8.4 mmHg). The difference was highly significant (P <0.0001) and was consistent when the confounding factors were considered. Correlation between the pO2 and probing depth approached statistical significance in smokers (r = ‐0.36, P = 0.0674) and significance in non‐smokers (r = ‐0.41, P = 0.0174). Correlation of the pO2 to the gingival So2 was highly significant in non‐smokers (r = 0.57, P = 0.0005), but no association was found in smokers (r = ‐0.08, P = 0.6975).Conclusions: These findings indicate that pO2 is lower in smokers than in non‐smokers, and that the pO2 in smokers is not influenced by gingival oxygen sufficiency. The present study may provide the basis of understanding environmental factors possibly associated with microbial flora in the pockets of smokers. J Periodontol 2000;71:550‐554.
Outcome Variables in Periodontal Research: Means and Threshold‐Based Site Changes
Authors: Machtei Eli E. , Schmidt Millicent , Hausmann Ernest , Grossi Sara , Dunford Robert , Davies Glenn , Chandler Julie , Genco Robert J. 
Published: February 2005

Background: The exclusive use of mean measurements in periodontal research might at times be misleading, as changes in different sites in the same individual might nullify each other. The purpose of the present study was to compare disease progression and response to periodontal therapy using both individual site activity with thresholds and mean patient changes.Methods: Seventy‐nine (79) subjects with established periodontitis were monitored for 1 year (no treatment [NTx] group); 108 subjects who received scaling, root planing, and quarterly prophylaxis were observed in a similar time interval (treatment [Tx] group). Probing depth (PD), attachment level (AL) and alveolar crestal height (ACH) were measured at baseline and 1 year using pressure‐sensitive probes and computer‐assisted image analysis of radiographs.Results: Mean reduction in PD (0.50 mm) was observed in the Tx group compared to a small increase (‐0.04 mm) in the NTx group (P = 0.0001). Treatment resulted in mean AL gain (0.44 mm) compared to net AL loss (‐0.21 mm) in the NTx group (P = 0.0001). Subjects in the Tx group had twice as many sites with AL gain (beyond the threshold) compared to NTx subjects (16.64 ± 1.07% versus 8.11 ± 0.68%) which was highly significant (P = 0.0001, Student t test). Similarly, although in the opposite direction, percentage of sites with AL loss beyond threshold was 6.21 ± 0.47% (Tx group) and 14.02 ± 1.15% (NTx group) which was also highly significant (P = 0.0001, Student t test). Change in ACH was minimal for the Tx group (‐0.07 ± 0.03 mm) while NTx subjects experienced greater bone loss throughout the year (‐0.16 ± 0.02 mm); percentage of sites with ACH loss was similar for both groups, while the Tx group had 3 times the number of sites with ACH gain (11.76% versus 3.42%), suggesting that the reduction in mean bone loss in the Tx group did not result from a reduction in losing sites, but rather from an increase in gaining sites. The use of both means and binary data seems to supplement the information regarding the nature and mechanism of disease progression and arrest.Conclusions: The characteristics of periodontal disease with its multifactorial patient, local, and site‐related etiology support the use of both mean and site‐based changes in clinical studies of periodontal disease and treatment. J Periodontol 2000;71:555‐561.