bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of a Non‐Steroidal Anti‐Inflammatory Drug on Tissue Levels of Immunoreactive Prostaglandin E2, Immunoreactive Leukotriene, and Pain After Periodontal Surgery
Authors: O'Brien Tiernan P. , Roszkowski Mark T. , Wolff Larry F. , Hinrichs James E. , Hargreaves Kenneth M.
Published: March 2012

The aim of this study was to measure tissue levels of immunoreactive prostaglandin E2 (iPGE2), immunoreactive leukotriene B4 (iLTB4), and pain after periodontal surgery and to evaluate the effect of the non‐steroidal anti‐inflammatory drug (NSAID), ibuprofen, on these levels. Two contralateral quadrants in each of nine patients were selected to undergo separate surgical procedures, one with ibuprofen (800 mg 1 hour presurgery and 400 mg postsurgery) and one with a placebo. Intra‐operatively, a custom‐made microdialysis probe, with a 3,000 dalton molecular weight cut‐off, was inserted beneath the soft tissue flap and a dialysate collected every 20 minutes for 4 hours after surgery. Pain perception was measured at the same time intervals using two pain scales. Dialysate samples were assayed using two enzyme immunoassays. Mean tissue levels of iPGE2 in the placebo group increased from 74 nM at 40 minutes to a peak of 261 nM at 200 minutes. Mean tissue levels of iLTB4 in the placebo group fluctuated between 0.2 and 0.6 nM. Pain levels in this group increased continuously with time, peaking at 4 hours. Mean tissue levels of iPGE2 in the ibuprofen group were significantly suppressed, exhibiting more than a 95% reduction. This was accompanied by a significant reduction in pain. Ibuprofen had no detectable effect on tissue levels of iLTB4. These data indicate that iPGE2 and iLTB4 are present at relatively high concentrations in the periodontal tissues after surgery. Since these concentrations exceed the Kd values for binding to their respective receptors, PGE2 and LTB4 may be associated with the development of postsurgical pain and inflammation. These data also indicate that ibuprofen can successfully inhibit iPGE2 production in the periodontal tissues and in this way may help reduce postoperative pain and inflammation. J Periodontol 1996;67:1307–1316.
Analytical Methodology in Quantitative Digital Subtraction Radiography: Analyses of the Aluminum Reference Wedge
Authors: Allen Kristin M. , Hausmann Ernest
Published: March 2012

An aluminum wedge can be used to quantify volumetric change in crestal alveolar bone which has been identified through subtraction radiography. This study compares two methods for using an aluminum wedge for this purpose: 1) the aluminum wedge is present in both radiographs and used to determine the aluminum equivalent bone density present in the region of change for each radiograph; and 2) the aluminum wedge is present in only one radiograph and the difference image of the wedge in the subtraction image is used to calculate the aluminum equivalent change in bone density. Pairs of standardized x‐rays were taken with synthetic bone chips of known weights placed when the second x‐ray was taken. The volumetric change produced by the bone chips was calculated by the two methods. The relationship of the calculated volumes to the chip weights had a higher r2 value (P < 0.05) for the two‐wedge method than for the one‐wedge method. The two‐wedge method is recommended for volumetric quantification of alveolar bone change. The influence of the clarity of the aluminum wedge image in the x‐ray pairs was also examined in this study and found to be significant. Attention must be given to factors which affect the aluminum wedge image characteristics to achieve optimal results. J Periodontol 1996;67:1317–1321.
Healing Response to Anorganic Bone Implantation in Periodontal Intrabony Defects in Dogs. Part I. Bone Regeneration. A Microradiographic Study
Authors: Clergeau Léon P. , Danan Marc , Clergeau‐Guérithault Suzanne , Brion Monique
Published: March 2012

The purpose of the present study was to explore the regenerative potential of anorganic bone plus collagen (AB‐C) in experimental intrabony defects. Eight healthy female beagle dogs, 3 to 4 years old and weighing 15 to 16 kilos, were used. After extraction of the mandibular third premolars (P3), surgical defects were created and inflammation induced by placement of cotton and steel braids. Eight weeks later, the braids were removed. The experimental lesions thus obtained were either treated by plain flap curettage (group 1: control) or were, in addition, implanted with AB‐C (group 2: experimental). Blocks of AB‐C alone were observed by scanning electron microscopy (SEM). The results show that the surface of the particles have the characteristics of a bone tissue. These particles are gathered together with a fibrillar network. Six, 18, and 36 weeks postoperative (PO), non‐decalcified specimens from both groups were examined histologically by contact microradiography. In group 1, no significant bone regeneration was observed at 6, 18, or 36 weeks PO. In group 2, trabeculae undergoing mineralization and circumscribing dense particles above the reference notch were seen at 6 weeks PO; 18 and 36 week specimens showed significant bone regeneration with more or less dense remaining particles. The periodontal ligament space was always clear and the only signs of ankylosis noticed were deep in the notch on one 18 week group 2 specimen and on one 36 week group 1 specimen. J Periodontol 1996;67:140–149.
Fate of Demineralized Freeze‐Dried Bone Allografts in Human Intrabony Defects
Authors: Reynolds Mark A. , Bowers Gerald M.
Published: March 2012

Demineralized freeze‐dried bone (DFDBA) is the most widely used allograft in periodontics. Little information exists, however, on the fate of DFDBA matrix or on the effects of residual particles within grafted defects. The purpose of this study was to histologically examine the fate of DFDBA used for regeneration in intrabony defects. A secondary objective was to compare the amount of new attachment apparatus formation, including component tissues, in relation to the presence or absence of residual graft material. Histologic data were obtained from earlier studies in which intrabony defects grafted with DFDBA were removed at 6 months en bloc and submitted for histologic examination. Histologic sections (1,120) from 12 patients with 32 grafted defects revealed that 72% of the grafted defects exhibited residual DFDBA particles. When present, DFDBA appeared amalgamated within the new viable bone. Data from 5 patients with 14 grafted sites permitted a within‐subject comparison of the amount of regeneration in relation to the presence or absence of residual graft material. Defects harboring residual graft particles exhibited significantly greater amounts of new attachment apparatus formation (1.72 mm vs. 0.20 mm), including new bone (2.33 mm vs. 0.23 mm), cementum (1.74 mm vs. 0.23 mm), and associated periodontal ligament than sites without evidence of graft matrix (P ≤ 0.05). No apparent differences were seen in the nature of the new attachment apparatus or component tissues, other than in amount of formation. Inflammation and graft containment appear to be important factors influencing the fate of DFDBA and the regenerative response. J Periodontol 1996;67:150–157.
Fractures of Hydroxyapatite‐Coated Blade Implants Connected With Natural Teeth. A Histological Study Using SEM, Light Microscopy, and an Image Processing System
Authors: Takeshita Fumitaka , Matsushita Yasuyuki , Ayukawa Yasunori , Suetsugu Tsuneo
Published: March 2012

A clinical study was conducted of 59 patients treated with 78 hydroxyapatite (HA)‐coated blade implants from August 1986. Five implants in 5 patients were broken at the neck portion, and one implant in one patient was removed from the jaw bone. The histological findings around a broken implant which was removed from the mandible are presented. These sections showed good adaptation of the bone to the implant without a fibrous layer. Histomorphometric evaluation of bone‐to‐implant contact showed 73.5%. The scanning electron microscopy image of the fractured surface revealed a fatigue fracture. The suspected cause of the fracture was stress concentration at the cervix portion, because of excessive mobility or deleterious change of abutment teeth. Consequently, the osseointegration/biointegration implants should not be connected with natural teeth. J Periodontol 1996;67:86–92.
The Microbiology of Early‐Onset Periodontitis: Association of Highly Toxic Actinobacillus actinomycetemcomitans Strains With Localized Juvenile Periodontitis
Authors: Zambon Joseph J. , Haraszthy Violet I. , Hariharan Govind , Lally Edward T. , Demuth Donald R.
Published: March 2012

Recent studies of the dental plaque bacteria associated with the various forms of early‐onset periodontitis confirm the importance of target periodontal pathogens such as Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Prevotella intermedia, and Porphyromonas gingivalis in these diseases. A. actinomycetemcomitans strains exhibit a wide range of variability in leukotoxin production. By virtue of a unique promoter for the leukotoxin (ltx) operon, highly leukotoxic A. actinomycetemcomitans strains (e.g., JP2) express 10‐ to 20‐times greater levels of leukotoxin than minimally toxic strains (e.g., 652). In dot blot hybridization and polymerase chain reaction (PCR) assays, the distribution of leukotoxic A. actinomycetemcomitans was examined among 165 fresh isolates and strains from our culture collection obtained from 91 human patients and non‐human primates. Highly leukotoxic A. actinomycetemcomitans strains were found in 22% of the subjects and represented 28% of the isolates examined. This is a much higher prevalence than reported in a similar survey of A. actinomycetemcomitans strains from Northern Europe. Patients harboring the highly leukotoxic strains were much younger (mean age 12.7 years) than those harboring minimally toxic A. actinomycetemcomitans (mean age 25.5 years). In addition, patients with localized juvenile periodontitis were shown to have a substantially higher prevalence of highly leukotoxic strains than healthy individuals or those with adult periodontitis. Fifty‐seven percent of the localized juvenile periodontitis patients harbored these strains and 64% of the isolates obtained from these patients were highly toxic A. actinomycetemcomitans. No highly toxic strains were identified from healthy individuals or from patients with adult periodontitis. The polymerase chain reaction assay could readily identify and distinguish the ltx promoters from highly toxic and minimally toxic A. actinomycetemcomitans in whole plaque samples. These data point to the importance of specific A. actinomycetemcomitans strains, as characterized by their expression of high levels of leukotoxin, in the pathogenesis of certain types of early‐onset periodontitis and, possibly, other forms of rapidly progressing periodontitis. J Periodontol 1996;67:282–290.
Virulence Factors of the Periodontopathogen Actinobacillus actinomycetemcomitans
Authors: Fives‐Taylor P. , Meyer D. , Mintz K.
Published: March 2012

Actinobacillus actinomycetemcomitans is an important periodontopathogen that has been implicated in juvenile and adult periodontitis. This capnophilic coccobacillus elaborates a number of virulence factors such as a bacteriocin, chemotaxis‐inhibiting factor, immunosuppressive factors, cytotoxic factors, Fc binding proteins, lipopolysaccharide (LPS), collagenases, antibiotic resistant determinants, adhesins, and invasins. The adhesins are associated with the bacterial surface or released into the surrounding environment in the form of vesicles. Adhesion to epithelial cells involves multiple determinants and is influenced by both bacterial and host environmental conditions. Invasion is a rapid process which occurs within 15 minutes post‐infection. Host cell actin is polymerized around the invading bacteria. Bacteria enter through a membraneruffled region of the host cell. This internalization process triggers vesicle formation on the bacteria. A. actinomycetemcomitans is taken up in a vacuole but is seen free in the cytoplasm in a short period of time. The number of internal organisms does not increase with time. A. actinomycetemcomitans can transcytose through the epithelial cells and is released from the host cell in 5 hours. We hypothesize that A. actinomycetemcomitans uses invasion of the epithelial cell as a mechanism to penetrate deeper tissues by cell‐to‐cell spread. J Periodontol 1996;67:291–297.
Antibody of the IgG2 Subclass, Actinobacillus actinomycetemcomitans, and Early‐Onset Periodontitis
Authors: Tew John G. , Zhang Ji‐Bo , Quinn Steve , Tangada Srilatha , Nakashima Keisuke , Gunsolley John C. , Schenkein Harvey A. , Califano Joseph V.
Published: March 2012

Susceptibility to early‐onset periodontitis (EOP) appears to be attributable to a gene inherited in an autosomal dominant pattern. This explains why EOP clusters in families and why about half of the family members develop periodontal disease early in life. Manifestation of EOP is variable, with some patients having a localized form restricted to first molars and incisors (LJP) and others with a severe generalized form of periodontitis (SP). The extent and severity of disease is less in patients who are seropositive for Actinobacillus actinomycetemcomitans than in seronegative patients, and this relationship prompted the hypothesis that anti‐A. actinomycetemcomitans helps limit disease. The dominant antibody is an IgG2 reactive with the serotypespecific carbohydrate. The incidence of the LJP form of EOP is about 10 times higher in blacks than in whites. Interestingly, blacks have higher levels of serum IgG2, a higher frequency of anti‐A. actinomycetemcomitans antibody, and higher serum titers of IgG2 anti‐A. actinomycetemcomitans which may help explain why the disease is localized. Studies in progress suggest that smoking reduces serum IgG2 levels in SP patients and is associated with more severe periodontal destruction. In marked contrast, IgG2 does not appear to be reduced in LJP patients who smoke, and smoking does not appear to increase periodontal destruction. We think that IgG2 anti‐A. actinomycetemcomitans is playing a role in limiting the extent and severity of disease in patients genetically susceptible to EOP. J Periodontol 1996;67:317–322.
FcγRIIa (CD32): A Potential Marker Defining Susceptibility to Localized Juvenile Periodontitis
Authors: Wilson Mark E. , Kalmar John R.
Published: March 2012

Epidemiologic studies indicate that blacks are at greater risk for development of localized juvenile periodontitis (LJP) than other ethnic groups. It has also been observed that, despite the relatively uncommon nature of this form of early‐onset periodontitis, LJP often tends to cluster within families, which suggests that susceptibility to this disease may be inherited. Immunologic studies of a predominantly black population of LJP subjects have revealed that many of these patients mount a strong IgG response to Actinobacillus actinomycetemcomitans. A substantial proportion of this response is comprised of antibodies of the IgG2 subclass. IgG antibodies are required for efficient phagocytosis and killing of A. actinomycetemcomitans by human neutrophils. Recognition of bacteria coated with IgG antibodies is a process which is mediated by IgG Fc receptors (FcγR) expressed on mononuclear and polymorphonuclear phagocytes. A major class of FcγR found on neutrophils is a transmembrane receptor (FCγRII, or CD32) which binds IgG with low affinity. Recently, a genetically determined biallelic polymorphism has been described for this receptor. One allotype, termed H131, binds human IgG2 efficiently, whereas the alternative form, R131, does not. Neutrophils expressing the H131 allotype of FCγRII readily ingest and destroy IgG2‐coated A. actinomycetemcomitans, whereas neutrophils bearing the R131 allotype do not. We hypothesize that the increased risk among blacks for development of LJP may be due to a combination of two factors, which include: 1) a tendency toward preferential synthesis of IgG2 antibodies to A. actinomycetemcomitans; and 2) an increased frequency of the R131 allele of FcγRIIa in this subject population. J Periodontol 1996;67:323–331.
Fusobacterium nucleatum T18 Aggregates Human Mononuclear Cells and Inhibits Their PHA‐Stimulated Proliferation
Authors: Haake Susan Kinder , Lindemann Robert A.
Published: March 2012

In previous studies Fusobacterium nucleatum has been shown to induce either stimulatory or inhibitory effects on human mononuclear cells. We examined the interaction of human mononuclear cells with human and cynomolgus monkey strains of F. nucleatum. Peripheral blood mononuclear cells (PBMCs) isolated from normal donors were aggregated in the presence of cells of F. nucleatum but not control bacteria. The aggregation of PBMCs and F. nucleatum T18 was inhibited by either L‐arginine, L‐lysine, or pretreatment of the bacterial cells with heat, but was unaffected by the presence of sugars or normal human serum. Strain T18 aggregated purified T‐cells and monocytes at approximately equal concentrations. When F. nucleatum T18 was incubated with PHA‐stimulated PBMCs, DNA synthesis in the PBMCs was significantly inhibited and detection of IL‐2Rα on the PBMCs was reduced. These studies indicate that F. nucleatum aggregates PBMCs, and that this interaction is associated with both an inhibition of PBMC proliferation and a decrease in IL‐2 receptor expression. The ability of F. nucleatum to inhibit mononuclear cell proliferation may be significant in the pathogenesis of periodontal diseases. J Periodontol 1997;68:39–44.
A Correlation Study of Inflammatory Cell Mobilization in Response to Subgingival Microbial Colonization
Authors: Leknes Knut N. , Lie Tryggve , Böe Olav E. , Selvig Knut A.
Published: March 2012

This study evaluated site‐by‐site the relations between subgingival microbial colonization and gingival tissue reactions. Experimental, deep periodontal defects were established at buccal surfaces of mandibular and maxillary canine teeth in 5 beagle dogs. The root surfaces were instrumented by a flame‐shaped, fine‐grained, rotating diamond point, or by a sharp curet. Following a 10‐day postsurgical healing period, the dogs were fed a plaque‐inducing diet for 70 days. The animals were then sacrificed and tissue blocks of the experimental sites including teeth and periodontal tissues were secured. The buccal gingiva was removed and processed for histomorphometric analysis while the teeth were prepared for scanning electron microscopic evaluation of the extent of subgingival microbial colonization. The results revealed that inflammatory cell density in the junctional epithelium and in the connective tissue were positively correlated to subgingival microbial colonization (P < 0.01). Furthermore, the degree of significance decreased with increasing distance from the plaque. The present study demonstrates that a close relation may exist between the extent of subgingival microbial colonization and inflammatory gingival tissue reactions. J Periodontol 1997;68:67–72.
The Effect of Plaque Retention on Cyclosporine‐Induced Gingival Overgrowth in Rats
Authors: Fu Earl , Nieh Shin , Wikesjö Ulf M.E.
Published: March 2012

The purpose of this study was to examine the role of plaque retention on cyclosporine A (CsA)‐induced gingival overgrowth. Forty‐five male Sprague‐Dawley rats, 15 for each of three CsA dosage conditions, were unilaterally ligated around the first mandibular molar (plaque retention). The silk ligature was left in place for 6 weeks. Contralateral first molars served as unligated controls. The daily dosage of CsA, administered by gastric feeding, was 0, 3, or 10 mg/kg body weight. Stone models from biweekly impressions of the molar sites were used to investigate development of gingival overgrowth. Rats were sacrificed at 6 weeks for histopathological and histometric examination of the molar sites. Gingival overgrowth was significantly increased in sites with higher CsA dosage, longer treatment duration, and ligation. Gingival overgrowth was enhanced in ligated sites regardless of CsA dosage. However, the odds ratio of ligated over unligated sites for gingival overgrowth increased with increasing CsA dosage. The histopathological and histometric examination revealed significantly increased gingival volume in ligated sites in CsA‐treated animals. The tissue enlargement included both the epithelium and the connective tissue; however, the epithelium to connective tissue ratio remained unaltered. Within limitations of the study, we suggest that plaque retention magnifies CsA‐induced gingival overgrowth; thus, dental plaque appears to be a cofactor in the development of CsA‐induced gingival overgrowth. J Periodontol 1997;68:92–98.
Differential Attachment of Oral Treponemes to Monolayers of Epithelial Cells
Authors: Carranza Nelson , Riviere George R. , Smith Kathryn S. , Adams Donald F. , Maier Tom
Published: March 2012

This in vitro study describes the attachment properties of several oral treponemes to monolayers of epithelial cells and the effect of epithelial cell confluence on treponeme attachment. Four serotypes of Treponema denticola, Treponema scoliodontum, three subspecies of Treponema socranskii and Treponema vincentii were tested with monolayers of epithelial cells of human and canine origin. Attachment of oral treponemes were compared to attachment by T. pallidum subsp. pallidum, and by the nonpathogen Treponema phagedenis. Results indicated that different serotypes of T. denticola had similar abilities to attach to epithelial cells. However, subspecies of T. socranskii differed in their ability to attach to epithelial cells. The proportion of epithelial cells susceptible to attachment by oral spirochetes was strongly related to the confluence level of the monolayer. In contrast, T. pallidum attached equally well to both epithelial cell lines at all confluence levels. T. phagedenis attached to <1% of all epithelial cells. In general, attachment of oral treponemes to canine cells was lower than to human cells, suggesting species‐specificity for adherence. Attachment of oral treponemes to epithelial cells may promote colonization of the periodontal pocket, as well as retention of treponeme colonies within plaque. The preference of oral treponemes to attach to cells of low confluence fields may translate in vivo to an increased ability to attach to cells which are actively dividing. Such cells are found in areas of repair, a common status within inflamed periodontal pockets. Furthermore, attachment of oral treponemes to epithelial cell barriers may promote or potentiate cytopathic processes. J Periodontol 1997;68:1010–1018.
Traumatic Bone Cyst Resembling Apical Periodontitis
Authors: Rosen Daren J. , Ardekian Leon , Machtei Eli E. , Peled Micha , Manor Ronen , Laufer Dov
Published: March 2012

Among the pseudocysts of the jaws, the traumatic bone cyst is known as an asymptomatic lesion often noted unintentionally during routine radiographic examinations. The lesion neither devitalizes the teeth within its borders, nor does it cause resorption of their roots. The well‐demarcated traumatic bone cyst often projects into the intraradicular septa and hence has been described as having scalloped borders. The following presentation is of a traumatic bone cyst that resembled periodontal pathology in its appearance. J Periodontol 1997;68:1019–1021.
The Ways and Wherefores of Immediate Placement of Implants Into Fresh Extraction Sites: A Literature Review
Authors: Schwartz‐Arad Devorah , Chaushu Gabriel
Published: March 2012

A waiting period of 12 months or longer to allow total socket healing used to be accepted protocol for placing dental implants. More than 15 years of research and clinical practice were needed for the concept of immediate endosseous implantation into fresh extraction sites to be accepted. Today the dilemma is no longer when, but which, protocol to follow. The diverse recommendations found in the literature leave the practitioner confused as to the methodology of choice. The conclusions drawn after reviewing the relevant literature on immediate dental implantation are: 1) implants placed into fresh extraction sockets have a high rate of survival, ranging between 93.9% to 100%; 2) implants must be placed 3 to 5 mm beyond the apex in order to gain a maximal degree of stability; 3) implants should be placed as close as possible to the alveolar crest level (0 to 3 mm); 4) there is no consensus regarding the need for gap filling and the best grafting material; 5) the use of membrane does not imply better results‐on the contrary, membrane exposure may carry complications in its wake; and 6) the absolute need for primary closure remains to be established. J Periodontol 1997;68:915–923.
Tooth Loss Due to Periodontal Abscess: A Retrospective Study
Authors: McLeod Dwight E. , Lainson Phillip A. , Spivey James D.
Published: March 2012

This retrospective study focused on the frequency of tooth loss due to periodontal abscess among 42 patients who were treated by a single clinician over a 5‐ to 29‐year period. A total of 114 patients were selected from the active periodontal recall schedule of a single periodontist at The University of Iowa College of Dentistry. The criteria for inclusion in the study included having a history of moderate to advanced periodontitis, being on 3 to 6 month recall periodontal maintenance care, and completion of active periodontal therapy prior to October 1987. Other parameters evaluated were age; gender; number of teeth present and missing at the initial, reevaluation, and last periodontal recall visit; initial periodontal prognosis; furcation involvement; non‐surgical and surgical periodontal therapy; and reasons for tooth loss. Patients were grouped according to the number of teeth lost following active periodontal treatment into well‐maintained (0 to 3), downhill (4 to 9), and extreme downhill (10 to 23) groups. Forty‐two of the 114 patients were identified as having one or more periodontal abscesses. A total of 109 teeth were affected by periodontal abscess of which 49 (45%) teeth were lost and 60 (55%) were successfully maintained over an average of 12.5 years (5 to 29 years). More furcated teeth were lost than nonfurcated teeth and teeth given a hopeless prognosis were lost more consistently than those given a questionable prognosis in all groups. The frequency of periodontal abscess and tooth loss per patient was greater in the downhill and extreme downhill response groups than the wellmaintained group. This suggests that teeth with a history of periodontal abscess can be treated and maintained for several years. J Periodontol 1997;68:963–966.
Tetracycline Fibers Plus Scaling and Root Planing Versus Scaling and Root Planing Alone: Similar Results After 5 Years
Authors: Wilson Thomas G. , McGuire Michael K. , Greenstein Gary , Nunn Martha
Published: March 2012

This paper presents 5‐year data pertaining to a subgroup of patients from a previous investigation who were treated with scaling and root planing plus tetracycline fibers. The parent study demonstrated that 6 months after therapy, scaling and root planing plus tetracycline fiber therapy was significantly better at reducing probing depth and gaining clinical attachment than scaling and root planing alone. However, the longterm data presented here show a regression from the original gains in clinical attachment levels in the fiber group. Ultimately, the use of fibers provided no significant advantage with regards to probing depth reduction or clinical attachment gain. Within the power of this study, which would have required 1.78 mm of change in clinical attachment to show a difference, there was no significant difference between the treatments at 5 years. This study underscores the need for additional long‐term evaluation of this mode of therapy. J Periodontol 1997;68:1029–1032.
Comparison of Porous Bone Mineral and Biologically Active Glass in Critical‐Sized Defects
Authors: Schmitt John M. , Buck David C. , Joh Seong‐Pil , Lynch Samuel E. , Hollinger Jeffrey O.
Published: March 2012

Several materials have been proposed as therapies to augment alveolar bone and to promote periodontal regeneration. However, there are an insufficient number of studies that effectively evaluated these therapies. Consequently, the purpose of this study was to compare bone regeneration promoted by porous bone mineral and biologically active glass. Unilateral critical‐sized defects (CSDs) were prepared in the radii of 24 rabbits, divided evenly between 2 time periods (4 and 8 weeks) and between 2 treatment groups (porous bone mineral and biologically active glass). Evaluations consisted of clinical examinations, standardized radiography at baseline and every 2 weeks thereafter, as well as histology and histomorphometry. Data were analyzed by an unpaired Student t‐test with significance established at P ≤ 0.05. We determined that CSDs treated with porous bone mineral were significantly more radiopaque than biologically active glass‐treated sites at both 4 and 8 weeks. Moreover, the amount of new bone was significantly greater at both 4 and 8 weeks in the porous bone mineral groups than in the biologically active glass groups. We concluded that in the rabbit radius CSD wound model, porous bone mineral appears to be more effective than biologically active glass in regenerating bone. J Periodontol 1997;68:1043–1053.
A Quantitative Assessment of Osteoinductivity of Human Demineralized Bone Matrix
Authors: Zhang Min , Powers Ralph M. , Wolfinbarger Lloyd
Published: March 2012

Demineralized bone matrix (DEM) is widely used in the repair of pathologies associated with skeletal defects and periodontal diseases. The present study was directed at establishing in vivo and in vitro models for a quantitative assessment of the osteoinductivity of DBM before clinical use. Athymic mice were used in an in vivo assay to overcome the species limitations (for human DBM) found in xenogeneic animal models. Calcium contents of explants, as an indicator of new bone formation, were assayed and expressed as a change in the weight percent calcium in the explant as compared to the weight percent of calcium in the implanted material. A total of 82 mice (2 implants per mouse) were used in this study. Significant amounts of new bone were induced in this animal model in response to implantation of DBM. Muscular implantation was found to be more osteoinductive (increases of 10.0 ± 0.4 calcium weight percent of explant) than subcutaneous implantation (increases of 1.62 ± 0.27 calcium weight percent of explant) and new bone formation in muscular implantation sites of athymic mice mimics endochondral bone formation. Between weeks 1 to 4, the weight of explanted materials did not significantly differ from the weight of the implanted material; however, by week 5 the expiant weight began to increase. Calcium deposition over the 5 weeks of implantation increased in a nearly linear fashion. Consequently week 4 was chosen as the optimum time for explantation in the in vivo assay in that sufficient calcium levels had been achieved without a significant increase in expiant dry weight. Aliquots of 10, 20, 30, and 40 mg per implantation site were used in dose response studies in the in vivo bioassay. Dose response curves with DBM exhibited maximal activity at the 20 mg DBM implant dose in the in vivo bioassay. An in vitro bioassay was also developed where human periosteal (HPO) cells were chosen because osteoprogenitor cells found in bone repair typically come from periosteal tissue. Alkaline Phosphatase (ALP) activity in confluent cell cultures of HPO cells exposed to DBM, as an indicator of Osteoblast induction, reached its highest level on day 5 of DBM treatment. Aliquots of 2, 5, 10, 20, 30, and 40 mg DBM per flask were chosen in dose response studies using the in vitro bioassay. These dose response studies with DBM revealed that quantities approximating 5 to 10 mg DBM in the in vitro model provided for maximal levels of ALP in cell extracts. A linear correlation (R2 = 0.7397) was demonstrated between the in vivo calcium reminerahzation assay and the in vitro ALP assay of osteoinductivity of DBM, suggesting that the in vitro assay can be used to quantitatively assess the osteoinductive potential of DBM where production and distribution of clinically usable DBM dictates rapid analysis. J Periodontol 1997;68:1076–1084.
Effect(s) of the Demineralization Process on the Osteoinductivity of Demineralized Bone Matrix
Authors: Zhang Min , Powers Ralph M. , Wolfinbarger Lloyd
Published: March 2012

The relationships between residual calcium levels and particle size of ground demineralized bone matrix and its osteoinductive potential were investigated using in vitro and in vivo assays. The effects of variable residual calcium levels, variable particle sizes, and donor age and gender were studied using a tissue culture‐based bioassay (in vitro) as well as an athymic mouse (in vivo) bioassay. The osteoinductive potential of the bone‐derived biomaterial was assessed by measuring the degree of new bone formation (change in percent calcium content after 4 weeks of implantation) in the in vivo assay and levels of alkaline Phosphatase activity associated with cultures of human periostea! cells (HPO cells) in the in vitro assay, respectively. Slightly demineralized bone matrix and overly demineralized bone matrix possessed a degree of osteoinductive potential whereas bone demineralized to levels of approximately 2% residual calcium provided for maximum osteoinductive potential in both assay systems. The osteoinductive potential of ground demineralized bone varied relative to the particle size such that DBM particles ranging from 500 to 710 microns provided for the highest level of calcium deposition (increase of 8.1 weight percent calcium) after 4 weeks of implantation in muscle pouches of an athymic mouse, whereas explanted particles less than 250 microns showed the lowest level of calcium deposition (increase of only 2.8 weight percent calcium). In the donor age and gender study, DBM from different donors were divided into 5 age groups for both female and male donor derived bone: less than 20, 21 to 30, 31 to 40, 41 to 50, and 51 to 60 year old age groups. This study indicated that DBM from female donors in the 31 to 40 years old age group and male donors in the 41 to 50 year age group possess the highest osteoinductive potential, whereas DBM derived from donor bone from both female and male donors in the 51 to 60 year age group presented the lowest osteoinductive potential. DBM derived from male and female donors did not in general show significant differences in osteoinductive potential. J Periodontol 1997;68:1085–1092.
Clinical and Microbiological Effects of Minocycline‐Loaded Microcapsules in Adult Periodontitis
Authors: Yeom Hey‐Ri , Park Yoon‐Jeong , Lee Seung‐Jin , Rhyu In‐Cheol , Chung Chong‐Pyoung , Nisengard Russell J.
Published: March 2012

Clinical and microbiological effects of subgingival delivery of 10% minocyclineloaded (MC), bioabsorbable microcapsules were examined in 15 adult periodontitis patients. Patients received oral hygiene instruction 2 weeks prior to the study. At baseline (day 0) all teeth received supragingival scaling (SC); 2 quadrants received no further treatment and 1 quadrant received subgingival scaling and root planing (SRP). In the fourth quadrant, the tooth with the deepest probing sites (at least 1 site ≥ 5 mm) was treated with minocycline microcapsules. The sites were evaluated at baseline and weeks 1, 2, 4, and 6. Clinical indices included bleeding on probing (BOP), probing depths (PD), and attachment loss (AL). Microbiological evaluations included percent morphotypes by phase‐contrast microscopy; cultivable anaerobic, aerobic, and blackpigmented Bacteroides (BPB); and percent Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, and Actinomyces viscosus by indirect immunofluorescence. In the SC+MC group, BOP, PD, and AL were significantly reduced from baseline for weeks 1 to 6. BOP in the SC+MC group was significantly reduced compared to the SRP group from weeks 2 to 6. In the SC+MC group the percent of spirochetes and motile rods decreased and the percent of cocci increased after 1 week. The increased cocci and decreased motile rods were statistically greater at weeks 4 and 6 in the SC+MC group compared to the SRP group. This study demonstrates that local subgingival delivery of 10% minocycline‐loaded microcapsules as an adjunct to scaling results in reduction in the percent sites bleeding on probing greater than scaling and root planing alone and induces a microbial response more favorable for periodontal health than scaling and root planing. J Periodontol 1997;68:1102–1109.
Placement of Implants Into Fresh Extraction Sites: 4 to 7 Years Retrospective Evaluation of 95 Immediate Implants
Authors: Schwartz‐Arad Devorah , Chaushu Gavriel
Published: March 2012

A 7‐year follow‐up of implants placed immediately after tooth extraction into fresh extraction sites is reported. Small autogenous bone chips (from bone adjacent to implant sites) were grafted into the defect between the implant and the socket walls when needed. Closure of the wound was obtained by coronal repositioning of the flap, and no membranes were used. Care was taken to minimize hematoma formation under the flap during healing by part‐time use of removable prosthesis with thick soft linings after implant surgery. At second stage surgery, mucoperiosteal flaps were apically repositioned for maximum attached gingival width and to reconstruct the vestibule. Minor complications such as exposure occurred in 16% of cases. Implant mean 5‐year cumulative survival rate was 95%. There was no implant loss after loading. The results indicated that implants placed into fresh extraction sites grafted with autogenous bone chips will heal predictably. J Periodontol 1997;68:1110–1116.
Crestal Bone Changes Around Titanium Implants. A Radiographic Evaluation of Unloaded Nonsubmerged and Submerged Implants in the Canine Mandible
Authors: Hermann Joachim S. , Cochran David L. , Nummikoski Pirkka V. , Buser Daniel
Published: March 2012

Current implant placement utilizes both nonsubmerged and submerged techniques. However, the implications of the location of a rough/smooth implant interface as well as the location of a microgap between implant and abutment on crestal bone changes are not well understood. The purpose of this study was to radiographically evaluate crestal bone changes around unloaded nonsubmerged and submerged titanium implants in a side‐by‐side comparison. Fifty‐nine (59) implants were placed at different levels to the alveolar crest in 5 foxhounds. Standardized radiographs were taken at baseline and at monthly intervals until sacrifice at 6 months. Radiographic assessment was carried out by measuring the distance between the top of the implant/abutment and the most coronal bone‐to‐implant contact (DIB), and by evaluation of bone density changes using computer‐assisted densitometric image analysis (CADIA). DIB measurements revealed that in 1‐part, nonsubmerged implants, the most coronal bone‐toimplant contact followed at all time points the rough/smooth implant interface. In all 2‐part implants, nonsubmerged and submerged, the most coronal bone‐to‐implant contact was consistently located approximately 2 mm below the microgap. In addition, CADIA values for all 2‐part implants were decreased in the most coronal area‐ofinterest (AOI). All bone changes were statistically significant and detectable 1 month after implant placement in nonsubmerged implants or 1 month after abutment connection in submerged implants. Neither implant position nor individual dog effects were statistically significant. These results demonstrate that the rough/smooth implant interface as well as the location of the microgap have a significant effect on marginal bone formation as evaluated by standardized longitudinal radiography. Bone remodeling occurs rapidly during the early healing phase after implant placement for nonsubmerged implants and after abutment connection for submerged implants. J Periodontol 1997;68:1117–1130.
Effects of Irradiation of an Erbium: YAG Laser on Root Surfaces
Authors: Yamaguchi Hiroyasu , Kobayashi Kazuyuki , Osada Reiko , Sakuraba Ei‐ichi , Nomura Tsuneo , Arai Takashi , Nakamura Jiro
Published: March 2012

The application of erbium:yag laser (Er:YAG) irradiation has been investigated for periodontal therapy. The purpose of this study was to evaluate the effects of Er: YAG laser irradiation on root surfaces using a scanning electron microscope (SEM) and to determine the laser's ability to remove lipopolysaccharides (LPS). Infrared spectrophotometry was used to investigate the effects of the laser on LPS applied to root dentin pellets. Premolare extracted for orthodontic reasons were prepared for this study. The crowns were resected below the cemento‐enamel junction, longitudinally sectioned, and the contents of the pulp chamber were removed. Then 15 root tips (5×5×1 mm) were classified into 3 groups of 5 each as follows: group 1, tips without any treatment; group 2, planed tips with the cement layers left untouched; and group 3, planed until the dentin surface was disclosed. The center of each specimen was used as the experimental irradiated area and the peripheral area served as a control. The quantity of vapor delivered by Er:YAG laser was highly increased, and the irradiated areas displayed little morphogenetic changes. The lyophilized sample LPS 0111 B4 from E. coli was then mixed with potassium bromide and pressed into a tablet, which was examined at 4,000–650 Kayser. The lyophilized LPS had a peak at 2.94 μm. LPS on the root dentin pellets was cleared away as much as possible by 150 washings in pyrogen‐free water using an ultrasonic cleaner. Five μl of 24 EU LPS solution was dropped on the root dentin pellets, which were then irradiated by the Er: YAG laser, and washed using the ultrasonic cleaner in pyrogen‐free water. The amount of the extracted LPS solution was determined by spectrophotometer at 405nm. The Er: YAG laser could remove 83.1% of the LPS. This study suggests that Er:YAG laser irradiation might be useful for root conditioning in periodontal therapy. However, clinical testing is necessary to establish what, if any, utility the Er:YAG laser has as a part of periodontal therapy. J Periodontol 1997;68:1151–1155.
A Phase I/II Clinical Trial to Evaluate a Combination of Recombinant Human Platelet‐Derived Growth Factor‐BB and Recombinant Human Insulin‐Like Growth Factor‐I in Patients with Periodontal Disease
Authors: Howell T. Howard , Fiorellini Joseph P. , Paquette David W. , Offenbacher Steven , Giannobile William V. , Lynch Samuel E.
Published: March 2012

The primary objective of this study was to assess the safety of recombinant human (rh) platelet‐derived growth factor‐BB (PDGF‐BB) and (rh) insulin‐like growth factor‐I (IGF‐I) when applied to periodontal osseous defects in humans; a secondary objective was to begin to accrue data on the therapeutic dose of these growth factors (GFs) required to stimulate periodontal regeneration. Thirty‐eight human subjects possessing bilateral osseous periodontal lesions were assigned to one of two treatment groups in a split‐mouth design. Following full‐thickness flap reflection, test sites received local application of the therapeutic drug delivered in coded syringes by a “masked” investigator. Two dose levels were tested, 50 μg/ml each of rhPDGF‐BB and rhIGF‐I in a gel vehicle (LD‐PDGF/IGF‐I) and 150 μg/ml each of rhPDGF‐BB and rhIGF‐I plus vehicle (HD‐PDGF/IGF‐I). Control treatment consisted of either conventional periodontal flap surgery or surgery plus vehicle. Safety analyses included physical examination, hematology, serum chemistry, urinalysis, antibody titers, and radiographic evaluation of bony changes. The primary therapeutic assessment was bone fill measured at re‐entry 6 to 9 months after treatment. No local or systemic safety issues were found as a result of GF administration. No patients developed antibodies to the rhGF proteins. In subjects treated with LD‐PDGF/IGF‐I, there were no enhancements in periodontal regeneration compared to controls. However, in patients treated with HD‐PDGF/IGF‐I, statistically significant increases in alveolar bone formation were noted as measured by surgical re‐entry 9 months following drug delivery (P < 0.05). This corresponded to an increase of 2.08 mm of new vertical bone height and 42.3% osseous defect fill in the HD‐PDGF/IGF‐I subjects versus only 0.75 mm and 18.5% gains in new bone height and osseous fill, respectively, in the controls. Furcation lesions, although limited in number, responded most favorably to treatment, with 2.8 mm horizontal osseous fill. The results from this study suggest that the local application of rhPDGF‐BB and rhIGF‐I to periodontal lesions is safe at the dose levels studied. LDPDGF/IGF‐I did not elicit increased defect fill compared to the control; however, HDPDGF/IGF‐I resulted in a significant promotion in bone regeneration. Additional studies are warranted to more fully characterize the effects of PDGF/IGF‐I on periodontal regeneration in humans. J Periodontol 1997;68:1186–1193.
Association of Oral Spirochetes From Sites of Periodontal Health With Development of Periodontitis
Authors: Riviere George R. , DeRouen Timothy A. , Kay Susan L. , Avera Sean P. , Stouffer Valorie K. , Hawkins Natalie R.
Published: March 2012

The purpose of this investigation was to determine whether the presence of diseaseassociated bacteria in health‐associated plaque correlated with susceptibility to periodontitis over time. Sites of periodontal health were identified in 65 adults. Six months later (recall 1), plaque was collected from sites that remained in periodontal health, and specific bacteria were detected using monoclonal antibodies in a microscopic assay. The spirochete morphogroup was identified by phase contrast microscopy. The relationship between detection at recall 1 and development of periodontitis over two successive 6‐month intervals (recalls 2 and 3) was evaluated by means of logistic regression using generalized estimating equations (GEE), from which odds ratios (OR) were estimated and tested for significance. Significant relationships were defined as those having ORs with P < 0.05. Ninety‐three of 1,032 sites developed signs of early periodontitis over the 12‐month interval between recall 1 and recall 3. The spirochete morphogroup (OR = 3.13, P < 0.001) and pathogen‐related oral spirochetes (PROS) (OR = 3.68, P < 0.001) were significantly associated with healthy sites that developed periodontitis. The association of Treponema socranskii was not significant (OR = 3.62, P = 0.0918). Odds ratios for Campylobacter rectus, Eikenella corrodens, and Porphyromonas gingivalis were less than 2.0 and not significant. Treponema denticola was not detected in health‐associated plaque from stable health sites and was detected in only three sites that progressed to periodontitis. These findings indicate that the presence of PROS and some unidentified spirochetes in healthassociated plaque is associated with increased susceptibility to periodontitis. J Periodontol 1997;68:1210–1214.