Abstracts for twelve presentations at the 91st AAP Annual Meeting in Denver, Colorado...
2005 Research Forum Oral Session Abstracts
Abstracts for twelve presentations at the 91st AAP Annual Meeting in Denver, Colorado.
The twelve abstracts below were presented at the 2005 AAP Annual Meeting Research Forum Oral Session on new and significant concepts related to periodontics. In the list below, click the title to view an abstract of the presentation.
- Biologic Width is Different Between Healthy and Periodontitis-Affected Teeth
Donna End, D.D.S., University of Pennsylvania, School of Dental Medicine - Gingival Interleukin Profiles Using Multiplex Bead Array and Microarray Technology
Steven P. Engebretson, D.M.D., Stony Brook University School of Dental Medicine and Columbia University School of Dental and Oral Surgery - Comparisons of Acellular Dermal Graft and Palatal Autograft in the Reconstruction of Keratinized Gingaval Around Dental Implants
Ji-Jong Yan, M.S., National Taiwan University Hospital - Effect of Enamel Matrix Derivatives on Collagen GTR-Based Root Coverage Procedure
Manal Trabulsi, Aramco Dental Services - Effects of EMD on the Expression of Cytokines in HPLF treated with P. gingivalis-LPS
Youngbum Park, School of Dental Medicine, SUNY at Buffalo - The Investigation of the Stem Cell Properties in the Periodontal Ligament Cells
Kanako Nagatomo, D.D.S., Tokyo Medical and Dental University - Platelet-rich Plasma Induces Nucleation of Mineralization in PDL Cell Cultures
Kazuhiro Okuda, Graduate School of Medical and Dental Sciences, Niigata University - Encapsulation and Osteoinduction of hPDLFs in Chitosan-Hydroxyapatite Microspheres
Bulend Inanc, Dt., Gazi University - Osteogenic Induction of hPDLF Under Two- and Three-Dimensional Culture Conditions
Bulend Inanc, Dt., Gazi University - Implications of Successful Long-Term Tooth Retention After Periodontal Therapy
Bryan Frantz, D.M.D., Scranton - Responses to Surgical Treatment for Periodontal Disease - Does Gender Matter?
Paul W. Kloostra, University of Michigan - Dental Care, Endotoxin Levels, Interleukin Polymorphism and Acute Coronary Syndrome
David Goteiner, D.D.S., University of Medicine and Dentistry of New Jersey
ETIOLOGY/PATHOGENESIS
Biologic Width is Different Between Healthy and Periodontitis-Affected Teeth
Donna End, D.D.S., University of Pennsylvania, School of Dental Medicine
- Background: The biologic width consists of the combined width of the junctional epithelium and the supracrestal connective tissue attachment zone, and is thought to be a constant dimension in health and with periodontitis. Scientific evidence is lacking to support this long-standing concept, and it was the purpose of the present study to address this important question by histometrically measuring the supracrestal connective tissue zone (SCTZ) in normal and periodontitis-affected teeth.
- Methods: Specimens consisted of bicuspids and molars from 17 squirrel monkeys which had periodontitis induced by tying silk ligatures at the gingival margins. Times from induction of periodontitis ranged from 10-52 weeks, and mesio-distal step-serial histological sections of the interproximal periodontium had been histometrically measured for loss of connective tissue attachment (CEJ – JE = LCT) and loss of crestal alveolar bone (CEJ – CR = LAB). These dimensions were used to calculate the width of the supracrestal connective tissue attachment zone (LAB – LCT = SCTZ), and the results compared with corresponding dimensions from 6 normal animals using t-tests and ANOVA statistical methods with the animal as the unit of analysis.
- Results: Histologic examination showed characteristic experimental periodontitis with loss of connective tissue attachment and alveolar bone, and with a distinct area infiltrated supracrestal connective tissue (ICT). The mean SCTZ was 466 + 47 (Mean + SE, microns), and this was statistically significantly greater than normal specimens (263 + 10, P<0.001). Within groups of periodontitis specimens, there was a variation in SCTZ (Minimum 353 + 30, Maximum 674 + 34), but all were greater than normal values. Analyses are continuing to clarify reasons for these variations, and the relationships to ICT.
- Conclusions: The supracrestal connective tissue attachment zone was significantly greater with periodontitis-affected teeth, and this finding contradicts the belief that biologic width is a constant in health and disease.
- Acknowledgments: Drs. Alan M. Polson, University of Pennsylvania and M. John Novak, University of Kentucky participated in this research. This study was supported by NIDR-D1648, Penn Perio Fund, and Alpha Omega Foundation.
Gingival Interleukin Profiles Using Multiplex Bead Array and Microarray Technology
Steven P. Engebretson, D.M.D., Stony Brook University School of Dental Medicine and Columbia University School of Dental and Oral Surgery
- Background: Chronic periodontitis (CP) is a multi-factorial disease characterized in part by increased levels of inflammatory cytokines in the gingival crevicular fluid (GCF) and gene expression levels in the gingival tissues. The purpose of this study was to investigate interleukin GCF profiles and gene expression patterns in CP and healthy subjects using newly developed multiplex bead array assays and oligonucleotide microarray technology.
- Methods: Periodontal clinical measures, GCF, and gingival biopsies were collected from 14 patients with untreated CP and 14 healthy volunteers. Multiplex bead array assay kits were used according to the manufacturers guidelines to simultaneously measure the levels of interleukins -1,-4,-6,-8,-10, and -1ra, from individual GCF samples. For the gingival tissue biopsies, standard oligonucleotide microarray protocols were used. Briefly, RNA was extracted from the gingival tissue biopsies, labeled, and hybridized to HG-U95Av2 GeneChip arrays. GeneChip data were analyzed using a commercially available software suite. The data were log transformed and correlation matrices were constructed to evaluate the relationships between tissue gene expression and GCF interleukin levels. ANOVA was used to compare healthy and diseased samples
- Results: Significant differences in cytokine levels were observed between healthy and diseased GCF and tissue samples. IL-1beta, IL-6, IL-8, and IL-10 levels were higher in diseased versus healthy GCF samples. IL-1 beta and IL-8, but not IL-6 were higher in diseased versus healthy gene expression samples. IL-4 and IL-1ra levels were not significantly different when healthy and diseased samples were compared for either GCF or tissue. Among all samples, a significant positive correlation was observed between IL-1 beta and both IL-6, and IL-8, for GCF and tissue. There were differences however, in both the direction and magnitude of these associations when diseased and healthy samples were compared.
- Conclusions: These data suggest a useful role for these high-throughput methodologies for the exploration of biologically relevant cytokine networks in both GCF and gingival tissue. Future studies utilizing these methodologies are likely to suggest new biological pathways involved in the pathogenesis of chronic periodontitis.
- Acknowledgments: Drs. Suzanne Torontali, Procter & Gamble; Lori Bacca, Procter & Gamble and Beth Jewell-Motz, Procter & Gamble participated in this research. This study was supported by National Institute of Dental and Craniofacial Research K23 DE-00449, and Oral Care Discovery.
PERIODONTAL PLASTIC SURGERY/RECONSTRUCTIVE SURGERY
Comparisons of Acellular Dermal Graft and Palatal Autograft in the Reconstruction of Keratinized Gingaval Around Dental Implants
Ji-Jong Yan, M.S., National Taiwan University Hospital
- Background: Autogenous free gingival graft have been proved to be predictable in increasing inadequate keratinized gingival zone. However, discomfort and pain from the donor site are unavoidable. An acellular dermal matrix(ADM) allograft has been successfully used in burn, plastic, and periodontal surgery. It substitutes as a donor tissue and eliminates the need for another surgical site. This study was to evaluate the applicability of ADM allografts in increasing the keratinized gingival with around dental implants.
- Methods: Eleven patients, total 32 dental implants with keratinized gingiva not more than 1mm on the facial aspect were selectively assigned to either ADM or palatal autograft (PAG) treatment. Nine implants received ADM graft and 23 implants received autogenous PAG harvested from the hard palates. Each recipient bed was prepared using partial-thickness dissection with apically repositioned flaps and donor tissues were immobilized with periosteal sutures. The width of keratinized gingival (KG) and other clinical periodontal parameters were recorded immediately before surgery and at the 6-months postoperative visit.
- Results: There was no significant difference in probing depth (PD), gingival recession (GR), plaque index (PlI) and gingival index (GI) at various observation periods between both groups. Both techniques provided an increase in KG width around dental implants (p < 0.01). The average KG gain was 2.44 ± 0.88mm in the ADM allograft at 6 months, which was less than that of palatal autograft (5.70 ± 2.27mm) at 6 months after therapy (p < 0.01). The shrinkage rates of graft were 75.56 ± 8.82% and 42.32 ± 21.64% in the ADM and PAG group, respectiively.
- Conclusions: ADM allograft was comparably less effective than autogenous PAG in terms of keratinized gingiva around dental implants. Both ADM & palatal autografts treatments could provide a significant increase in areas of deficient attached or keratinized gingiva on the facial aspects of dental implants. However the ADM allograft did have additional advantages, avoidance of the second surgical site and its associated postoperative pain and bleeding
- Acknowledgments: Drs. Man-Ying Wong, Department of Periodontology, National Taiwan University; Cheing Meei Liu, Department of Periodontology, National Taiwan University; Yi-Min Tsai, Department of Periodontology, National Taiwan University and Lein-Tuan Hou, Department of Periodontology, National Taiwan University participated in this research. This study was supported by National Taiwan University Hospital.
Effect of Enamel Matrix Derivatives on Collagen GTR-Based Root Coverage Procedure
Manal Trabulsi, Aramco Dental Services
- Background: Enamel matrix derivatives (EMD) has been shown to promote periodontal wound healing and/or regeneration when applied to tooth root surfaces in soft tissue dehiscence models. In addition, guided tissue regeneration (GTR)-based root coverage using collagen membrane (GTRC) has showed promising results. However, limited information is available regarding how EMD may influence GTRC outcome.
- Methods: 26 patients with Miller's Class I or II recession defects of ≥ 2.5 mm were recruited for the study. Subjects received either EMD + collagen (EMDC- test group) or collagen membrane (GTRC- control group). Clinical parameters, including plaque index (PLI), gingival index (GI), clinical attachment levels (CAL), recession depth (RD), recession width (RW), probing depth (PD), gingival tissue thickness (GTT), and width of keratinized gingiva (KG) were assessed at baseline, 3 and 6 months after surgery. ANOVA measure was used to determine differences between treatment groups and time effect.
- Results: Both treatments (GTRC and EMDC) resulted in a statistically significant decrease in RD and RW between baseline and six months (P < 0.05). However, no difference was noted between treatment groups. The percent of root coverage after six months was 75% for GTRC and 63% for EMDC. Complete 100% root coverage was achieved in 5/13 patients in the GTRC group, compared to 1/13 patient in the EMDC group. There was a statistically significant gain (P < 0.05) in <st1: State w:st="on"><st1:place w:st="on">CAL</st1:place></st1:State> between baseline and six months in both groups. No other significant differences were noted on other clinical parameters (PD, GTT, KG, GI, PLI and WHI).
- Conclusions: GTR-based root coverage utilizing collagen membrane, with or without Enamel Matrix Derivative, can be successfully used in obtaining gingival recession coverage. The application of EMD during GTRC procedures did not add additional benefit to the final clinical outcome
- Acknowledgments: Drs. Tae-Ju Oh, Graduate periodontics program, University of Michigan; Robert Eber, Graduate periodontics program, University of Michigan; Daniel Weber, Graduate periodontics program, University of Michigan and Hom-Lay Wang, Graduate periodontics program, University of Michigan participated in this research. This study was supported by the University of Michigan Periodontal Graduate Student Research Fund. Biora, Inc., Chic.
PERIODONTAL REGENERATION
Effects of EMD on the Expression of Cytokines in HPLF treated with P. gingivalis-LPS
Youngbum Park, School of Dental Medicine, SUNY at Buffalo
- Background: Use of Enamel matrix derivative (EMD) is a well known periodontal treatment for Guided Tissue Regeneration (GTR) although its ultimate mechanism of action is unknown. Clinically, bacterial LPS remaining on the root surface or in the tissue enhances the production of inflammatory cytokines (i.e. IL-6 and IL-8) related to wound healing, but over expressed cytokines activate alveolar bone loss adversely. The purpose of this study was to evaluate the effects of EMD on the secretion of inflammatory cytokines in HPLF exposed to P. gingivalis-LPS (LPS).
- Methods: Human periodontal ligament fibroblasts (HPLF) were seeded into 6-well culture plates. Cell culture supernatants of experimental samples were collected for immunoassay. There were 7 experimental groups; 1. Control group (HPLF) without (-) EMD and LPS (5 µg/ml concentration); 2. Positive control (human osteoblasts (HOB) with (+) LPS); 3. HPLF + EMD (10 µg/ml); 4. HPLF + EMD (50 µg/ml); 5. HPLF + LPS; 6. HPLF + EMD (10 µg/ml) + LPS; 7. HPLF + EMD (50 µg/ml) + LPS. Cytokines were detected using a ProteoPlex® 16-well Human Cytokine Array Kit designed for multiplex detection and measurement of 12 pro- and anti-inflammatory cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, GM-CSF, IFN-γ, and TNF-α). ArrayVision 8.0 and the ProteoPlex Analyzer Excel program were used for data extraction and analysis.
- Results: The cytokine assay showed that HPLF produced IL-6 and IL-8 in all groups except positive control group (HOB + LPS) produced IL-1α (7.3 pg/ml). The HPLF + EMD (50 µg/ml) + LPS group showed significantly higher production of IL-6 (1143.9 pg/ml) and IL-8 (1056.9 pg/ml) than control group (333.7 pg/ml of IL-6 and 612.2 pg/ml of IL-8) and the HPLF + LPS group (410.1 pg/ml of IL-6 and 320.5 pg/ml of IL-8). The HPLF + EMD (10µg/ml) + LPS group produced IL-6 (557.1 pg/ml) and IL-8 (430.3 pg/ml) which were similar to control group. Both of the HPLF + EMD at low concentration (10 µg/ml) and high concentration (50 µg/ml) groups produced IL-4 (3.1 pg/ml and 1.3 pg/ml, respectively) and IL-10 (8.5 pg/ml and 3.3 pg/ml).
- Conclusions: The results showed that cytokine production in HPLF differed from HOB. Furthermore, EMD at a low concentration might have a role to inhibit the production of IL-6 and IL-8 in HPLF treated with LPS in vitro assay. However, a higher concentration of EMD with LPS resulted in increased levels of the expression of IL-6 and IL-8. This study suggests that when LPS is present, EMD may affect a concentration dependent effect on cytokine levels.
- Acknowledgments: Drs. Darunee NaBadalung, Assistant Professor, Restorative Dentistry, SDM, SUNY at Buffalo; Hiran Perinpanayagam, Assistant Professor, Periodontics and Endodontics, SDM, SUNY at Buffalo; Judith D. Lampasso, Assistant Professor, Orthodontics, SDM, SUNY at Buffalo; Sebastiano Andreana, Clinical Assistant Professor, Periodontics and Endodontics, SDM, SUNY at Buffalo and Rosemary Dziak, Professor, Oral Biology, SDM, SUNY at Buffalo participated in this research. This study was supported by the Department of Periodontics and Endodontics and Oral Biology, School of Dental Medicine, SUNY at Buffalo.
The Investigation of the Stem Cell Properties in the Periodontal Ligament Cells
Kanako Nagatomo, D.D.S., Tokyo Medical and Dental University
- Background: The regenerative potential of stem cell, which could be explained by their characteristics of self renewal and multi-potency, are recently focused on the regenerative therapy. Lines of studies suggest that periodontal ligament (PDL) cells play an important role in periodontal regeneration. Since these experiments were carried out with heterogeneous cell populations from PDL tissue, it is difficult to determine the individual cellular phenotypes. In this study, we investigated the characterization of the PDL cells to clarify their stem cell property.
- Methods: PDL cells were obtained from clinically healthy teeth extracted from 17-22 years old subjects (n=4). PDL cells were plated sparsely to generate single-cell derived colonies in α-MEM supplemented with 20% FBS. To determine their stem cell property, immunostaining for STRO-1(hybridoma bank univ.of IOWA, Simmons 1991), fluorescent-activated cell sorters (FACS) analysis for stem cell markers including SH-2 and ALCAM, proliferation assay for self renewal and differentiation assay for multi-potency were performed. Alizarin Red-S staining and calcium intake were analyzed for osteogenic differentiation of PDL cell colonies. Oil Red-O staining and reverse transcriptase-polymerase chain reaction (RT-PCR) were also performed to examine adipogenic differentiation of PDL cell colonies.
- Results: PDL cells proliferated and made colonies derived from a single cell. Some colonies showed positive staining for STRO-1 and differentiated into adipocytes and osteoblasts indicating their multi-potency. Adipogenic specific markers, which are PPARγ, FABP4 were confirmed by RT-PCR. Calcium intake was increased when PDL cell colonies were cultured in the osteogenic differentiation medium. FACS analysis showed PDL cells included cell populations which express stem cell markers, SH-2 and ALCAM.
- Conclusions: Our findings suggested that PDL cells have the stem cell properties, self-renewal and multi-potency, and would make a promise as a therapeutic approach, such as cell transplantation, for reconstruction of tissues destroyed by periodontal diseases.
- Acknowledgments: Drs. Motohiro Komaki, Periodontology, Department of Hard Tissue Engineering ,Graduate School, Tokyo Medical and Dental University; Ichiro Sekiya, Periodontology, Department of Hard Tissue Engineering, Graduate School, Tokyo Medical and Dental University; Takeshi Muneda, Periodontology, Department of Hard Tissue Engineering, Graduate School, Tokyo Medical and Dental University and Isao Ishikawa, Periodontology, Department of Hard Tissue Engineering, Graduate School, Tokyo Medical and Dental University participated in this research.
Platelet-rich Plasma Induces Nucleation of Mineralization in PDL Cell Cultures
Kazuhiro Okuda, Graduate School of Medical and Dental Sciences, Niigata University
- Background: Platelet-rich plasma (PRP) has been used to promote periodontal regeneration following that TGF-beta1 and PDGF-AB can stimulate cell proliferation at the site of injury. We have demonstrated that fibrin clot formation by PRP stimulates type I collagen production and that unidentified factors in PRP up-regulate alkaline phosphatase (ALP) in human periodontal ligament (PDL) cell cultures. ALP often accompanies promotion of mineralization. Therefore, this study was designed to evaluate the ability of PRP to stimulate mineralization in PDL cell cultures.
- Methods: PRP was prepared by an established two-step centrifugation protocol using blood obtained from human adult volunteers or from rats. Human and rat PDL cells cultured on native or atelocollagen (PC)-coated plates were continuously treated with PRP in medium containing 2% fetal bovine serum. Calcium deposits were stained with alizarin red-S (AR-S) and also observed by transmission electron microscopy. Expression of proteins characteristic of the osteoblastic phenotype [ALP, Cbfa1, bone sialoprotein (BSP), osteocalcin (OCN)] at the level of mRNA were evaluated by RT-PCR. Nucleation of mineralization was examined by transmission electron microscopy (TEM).
- Results: After 20-days of treatment, PRP substantially up-regulated expression of several osteoblastic markers (i.e., Cbfa1, BSP, and OCN) and concomitantly stimulated mineralization in rat PDL cells cultured on PC-coated plates. On day-16 in PRP-treated human PDL cell cultures, in which AR-S-stained mineral deposits were not yet readily discernible, TEM findings demonstrated that mineralized spicules were deposited onto platelet aggregates but not on or within matrix vesicle-like structures.
- Conclusions: PRP does not fully induce the osteoblastic phenotype in PDL cells; instead, PRP promotes in vitro mineralization both by stimulating cellular ALP activity and by providing a nucleus for mineralization in culture. PRP has not been reported to be capable of stimulating ectopic mineralization, but PRP is expected to stimulate mineralization in the presence of nominal ALP activity such as that found at the bone mineralization front.
- Acknowledgments: Drs. Tomoyuki Kawase, Division of Cellular Pharmacology, Graduate School of Medical and Dental Sciences, Niigata University; Yoshinori Saito, Division of Periodontology, Graduate School of Medical and Dental Sciences, Niigata University; Norio Amizuka, Division of Oral Anatomy, Graduate School of Medical and Dental Sciences, Niigata University; Hironobu Suzuki, Division of Anatomy and Cell Biology of the Hard Tissue, Graduate School of Medical and Dental Sciences, Niigata University and Hiromasa Yoshie, Division of Periodontology, Graduate School of Medical and Dental Sciences, Niigata University participated in this research.
CELLULAR/MOLECULAR BIOLOGY
Encapsulation and Osteoinduction of hPDLFs in Chitosan-Hydroxyapatite Microspheres
Bulend Inanc, Dt., Gazi University
- Background: Periodontal ligament cells play a crucial role in the regeneration of periodontal tissues and an undifferentiated mesenchymal cell subset is thought to exist within this population. The aim of this study was to assess the osteogenic differentiation potential of human periodontal ligament fibroblasts (hPDLFs) in three-dimensional osteogenic culture environment following encapsulation in chitosan-hydroxyapatite microspheres with the size range of 400-500 micrometers.
- Methods: Human PDLF cultures were established and characterized morphologically and immunohistochemically. Two experimental groups were formed: i. Three-dimensional static culture of C/HA encapsulated hPDLFs, and ii. Three-dimensional dynamic culture of C/HA encapsulated hPDLFs in a rotating wall-vessel bioreactor. Two-dimensional culture as single cell monolayer served as the control. The cells were cultured in standard culture medium supplemented with osteogenic inducers, namely beta-glycerophosphate, dexamethasone and ascorbic acid. After 21 days, immunohistochemistry was performed using antibodies against osteonectin, osteopontin, bone-sialoprotein and osteocalcin as osteogenic differentiation markers. Phase-contrast and SEM observations were used for histological and morphological evaluation.
- Results: The combined effects of osteoinductive medium and HA-containing microsphere material on encapsulated PDLFs resulted in a transformation of a considerable portion of the cells into osteoblastic lineage at the end of the 21-day static and dynamic culture. Phase-contrast microscopy revealed the transition from spindle-shaped fibroblastic to round shaped osteoblast-like morphology in the majority of the cells, in two-dimensional single cell monolayer cultures. SEM evaluation confirmed the osteoblast-like morphology of hPDLFs encapsulated in C/HA microspheres. Immunohistochemical detection of enhanced osteogenic marker expression further proved the phenotypical shift towards the osteogenic lineage.
- Conclusions: Results demonstrate the ability of human periodontal ligament fibroblasts to undergo osteogenic differentiation upon induction in vitro, both under two- and three-dimensional culture conditions. Chitosan-hydroxyapatite microspheres in microgravity bioreactor may serve as a suitable three-dimensional environment to support the osteogenic differentiation of human PDLFs, in vitro.
- Acknowledgments: Drs. Y.Murat Elcin, Professor, Ankara University, Faculty of Science and Biotechnology Institute and A.Eser Elcin, Assistant Professor, Gazi University, GEF, Biology Division participated in this research. This study was supported by the Ankara University Biotechnology Institute, TÜBA-GEBÄ°P(2002-1-10), and Gazi University BAP.
Osteogenic Induction of hPDLF Under Two- and Three-Dimensional Culture Conditions
Bulend Inanc, Dt., Gazi University
- Background: Human periodontal ligament fibroblasts (hPDLFs) play a key role in the regeneration of periodontal compartment during guided tissue regeneration procedures. This property of the periodontal ligament is attributed to the progenitor cell subsets residing in the area. The aim of this study was to investigate whether human periodontal ligament fibroblastic cells could undergo an osteogenic differentiation under two- and three-dimensional culture conditions upon osteogenic induction.
- Methods: Human periodontal ligament fibroblasts were isolated from 6 healthy donors, cultured and expanded according to standart protocols. The cells were characterized morphologically and immunohistochemically. Then, three different culture conditions were established: i. 2D- culture as single cell monolayer, ii. 3D-static culture on poly(PLGA) scaffolds, and iii. 3D-dynamic culture on mineralized PLGA scaffolds inside the NASA approved bioreactor simulating microgravity conditions. The osteogenic induction medium consisted of DMEM containing 20% FCS, 10 nM dexamethasone, 50 microgram/ml ascorbic acid and 10 mM beta-glycerophosphate. After 21 days of osteogenic induction, the specimens were fixed and analyzed by histology. Mineralization was assayed using Alizarin Red staining; the phenotypical changes were evaluated by immunohistochemistry.
- Results: After 21 days of osteogenic induction, the majority of cells in monolayer cultures had undergone differentiation towards osteogenic lineage as indicated by morphological changes, mineralization assay and some phenotypic properties. However, immunohistochemistry revealed that the scaffold cultures expressed higher levels of osteogenic marker proteins, compared to monolayers. Additionally, hPDLFs/PLGA constructs in bioreactor showed an increased expression of osteopontin and osteocalcin, compared to static 3D-culture after 21 days.
- Conclusions: Results indicate that human periodontal ligament contains a subpopulation of cells capable to undergo osteogenic differentiation and presumably contributing to regeneration of bone defects in the adjacent area. Human PDLFs-seeded mineralized PLGA scaffolds in microgravity bioreactor may be used to support osteogenic differentiation in vitro; thus, this system may offer new potential benefits as a tool for periodontal tissue engineering.
- Acknowledgments: Drs. Y.Murat Elcin, Professor, Ankara University, Faculty of Science and Biotechnology Institute and A.Eser Elcin, Assistant Professor, Gazi University, GEF, Biology Division participated in this research. This study was supported by the Ankara University Biotechnology Institute, TÜBA-GEBÄ°P(2002-1-10), and Gazi University BAP.
PREVENTION/DIAGNOSIS/RISK
Implications of Successful Long-Term Tooth Retention After Periodontal Therapy
Bryan Frantz, D.M.D., Scranton
- Background: A basic tenet of periodontal therapy is long-term retention of teeth in comfort and function. There has been a recent trend in therapy to extract periodontitis-affected teeth and replace with implants because of apparent unpredictable treatment outcomes in the private practice environment. The purpose of the present study was to try and clarify this situation by analyzing tooth retention outcomes in a large data base with a minimum of ten years post-periodontal treatment. The therapeutic approach had been directed primarily at resolution of inflammation.
- Methods: The population comprised 150 patients, 105 females, 45 males, age ranges 27-75 yrs, mean 48.2 yr. Active treatment comprised oral hygiene instruction, scaling, reevaluation of responses, and surgical therapy utilized a variety of different techniques. After active treatment, patients went on a maintenance program of professional examination and scaling every 3 months, and appointments were alternated between the periodontal and referring dentist office. Nine cases were AAP type II, 88 were type III, and 53 type IV. The average follow-up period was 12.6 years, ranging 10.1- 16.1years. The total number of teeth entering into initial treatment were 3,738, mean per patient 24.9. During treatment, 56 teeth were extracted, average extraction per patient = 0.37. Thus, number of teeth remaining after treatment was 3,682, mean per patient 24.5.
- Results: Over the 12-year maintenance period in these 150 patients, the total number of teeth lost was 239. Sixty-three were lost for non-periodontal reasons; the 176 lost for periodontal reasons were because of terminal bone loss (110 teeth), exfoliation (1 tooth), furcation breakdown (34 teeth), and endo-perio (31 teeth). The 176 teeth lost due to periodontal disease represented 4.7 % of the total 3,682 teeth at risk (meaning 95.3% tooth retention), with an average tooth loss per patient of 1.2. Seventy-five patients lost teeth, and 10 patients lost 3 or more teeth indicating that some were at greater risk. Clinical and radiographic data across time showed that almost all patients had changed very little since completion of treatment.
- Conclusions: Rate of tooth loss after therapy was extremely slow with over 95% tooth retention after 12 years. This rate of retention seems overall more favorable than implant success rates over a similar period of time. Also, a stable periodontal condition over 12 years meant that all treatment planning options were still available to the patient. Finally, this approach toward tooth retention may be economically more beneficial to the patient.
- Acknowledgments: Drs. Alan M. Polson, University of Pennsylvania and Alexis Gearhart, Scranton participated in this research.
Responses to Surgical Treatment for Periodontal Disease - Does Gender Matter?
Paul W. Kloostra, University of Michigan
- Background: This study was conducted to investigate whether male and female patients are equally likely to choose surgical vs. non surgical treatment, and whether male and female patients who chose surgical treatment differ in their (a) psychological responses (well-being, depression, stress, and anxiety) at the day of surgery, (b) wound healing (inflammation, swelling, epithelialization, wound integrity) 2 weeks after surgery, and (c) reported levels of pain and use of pain medication 2 and 4 weeks after surgery.
- Methods: Data were collected from 72 dental patients (34 male / 38 female; mean age: 54.74±13.21 years). Twenty-five surgically treated patients (11 male / 14 female; mean age: 53.20 ±11.63 years) responded to a survey at the day of their treatment to evaluate their psychological state, in particular their well-being, depression, stress, and anxiety. Well validated and reliable scales were used to measure these psychological constructs (Bradburn Well Being Scale; Center for Epidemiological Study Depression Scale; Perceived Stress Scale; Trait Anxiety Inventory). They also responded to two follow up surveys (2 and 4 weeks after surgery) concerning their experienced pain and use of pain medication (amount and type). Their providers evaluated their wound healing (inflammation, swelling, epithelialization, wound integrity) at the 2-week follow up visit.
- Results: Men and women did not differ in their preference for surgical vs. non-surgical treatment for periodontal disease. At the day of treatment, surgically treated male patients reported poorer well-being (p=.017), higher levels of depression (p=.030), had a tendency to report more stress (p=.071), but not significantly different levels of anxiety, compared to surgically treated female patients. However, 2 weeks after treatment, male patients had better epithelialization (p=.028), and a tendency to have less inflammation (p=.088), less swelling (p=.062), and better wound integrity (p=.10) than female patients. At 2 and 4 weeks after surgery, no differences in experienced pain as well as amount and type of pain medication were found.
- Conclusions: These findings indicate that the gender of patients does not affect the decision of having either surgical or non-surgical treatment. Male patients reported more psychological impact on the day of surgery than female patients. In addition, while men and women had similar pain experiences as well as similar amount of medication use after surgery, male patients had better wound healing than female patients’ at a 2 week follow-up visit.
- Acknowledgments: Drs. Robert M. Eber, University of Michigan; Hom-Lay Wang, University of Michigan and Marita R. Inglehart, University of Michigan participated in this research. This study was supported by Dr. Laurie McCauley.
Dental Care, Endotoxin Levels, Interleukin Polymorphism and Acute Coronary Syndrome
David Goteiner, D.D.S., University of Medicine and Dentistry of New Jersey
- Background: Recent studies have established an association between poor dental health and acute coronary syndrome (acute myocardial infarction and unstable angina), or ACS. The purpose of this study was to determine whether ACS and angina patients have higher levels of endotoxin at the time of admission to the hospital, and a greater prevalence of the IL-β polymorphism than comparison groups without ACS or angina and correlate it with dental history and care.
- Methods: 137 patients hospitalized for ACS or angina after visiting the emergency room with chest pain were contrasted with a group of 37 patients who were dismissed from the ER and a group of 101 patients that entered the hospital for elective procedures. Residual blood, collected upon admission to assess for infarction, was used to determine IL-1β polymorphism and the presence of endotoxins (LPS). Following hospital discharge and patient consent, a health questionnaire was completed, and data from the hospital, dental records and radiographs were obtained and analyzed.
- Results: ACS/angina patients reported a longer median time between prophylaxis and appearance at the ER (6.5 vs 3.0 mos., p=.008), had fewer teeth (22.9 vs 26.3, p<.001), evidenced a higher incidence of severe periodontitis (38.5 vs 9.1%, p<.05) and reported a higher incidence of being told they had periodontitis (88.6 vs 21.7%). Their dentist reported a higher incidence of untreated pathology (50.4 vs 24.2%, p<.01). LPS levels increased directly with triglyceride levels (p=.002) and inversely with HDL levels (p=.010). ACS/angina patients more often evidenced IL-1β positive polymorphism than historical controls (p<.05). In patients over 60 the prevalence of the positive gene was enriched (p=.009) with IL-1α+4845T significantly increasing (p=.015).
- Conclusions: The production of endotoxin and inflammatory cytokines in IL-1 positive individuals with poor dental care may be associated with an acute coronary event.
- Acknowledgments: Drs. Robert Ashmen, University of Medicine and Dentistry of New Jersey; Neal Lehrman, University of Medicine and Dentistry of New Jersey; Malvin N. Janal, University of Medicine and Dentistry of New Jersey and Barnet Eskin, Morristown Memorial Hospital participated in this research.
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