No abstract available.
Bone Density*

The role of the periosteum on osteointegration of Bio-Oss(R)(Geistlich, Wolhusen/Switzerland) was studied in rabbit calvarial defect. 12 New Zealand white male rabbits between 2.8 and 4 kg were included in this randomized, blinded, prospective study. Each rabbit was anesthetized with Ketamine HCl(5 mg/kg) and Xylazine HCl(1.5 ml/kg). An incision was made to the bony cranium and the periosteum was reflected. Using a 6-mm trephine bur(3i. USA), four 8-mm defects were created with copious irrigation. The defects were classified into barrier membrane(Tefgen(R), Lifecore Biomedical, Inc, U.S.A.) only group as a control, Bio-Oss(R) with barrier membrane group, Bio-Oss(R) with periosteum covering group, and Bio-Oss(R) without periosteum covering group. There were 2 rabbits in each group. The wound was closed with resorbable suture materials. Rabbits were sacrificed using phentobarbital(100 mg/kg) intravenously at 1, 2, and 4 weeks after surgery. The samples were fixed in 4% paraformaldehyde, and decalcified in hydrochloric acid decalcifying solution(Fisher Scientific, Tustin, CA) at 4degrees C for 2-4 weeks. It was embedded in paraffin and cut into 6 micrometer thickness. The sections were stained with H & E and observed by optical microscope. The results were as follows; 1. The periosteum played an important role in osteointegration of Bio-Oss(R) in bone defects. 2. When the periosteum remained intact and Bio-Oss(R) was placed on the defect, Bio-Oss(R) with periosteum covering has been incorporated into the newly formed bone from 2-week postoperatively. 3. When the periosteum was removed at the surgical procedure, invasion of connective tissue took place among the granules, and new bone formation was delayed compared to periosteum covering group. Therefore, when the bone grafting was performed with periosteal incision procedure to achieve tension-free suture, the integrity of the overlying periosteum should be maintained to avoid fibrous tissue ingrowth.
Bone Regeneration* ; Bone Transplantation ; Connective Tissue ; Humans ; Hydrochloric Acid ; Ketamine ; Male ; Membranes ; New Zealand ; Osteogenesis ; Paraffin ; Periosteum* ; Prospective Studies ; Rabbits ; Skull ; Sutures ; Wounds and Injuries ; Xylazine

Helicobacter pylori(H. pylori) has been associated with the cause of chronic gastritis, peptic ulcers and gastric cancer. Although it may be transmitted through the oral cavity, it is unknown whether the oral cavity acts as a reservoir of H. pylori. The purpose of this study was to investigate the mode of detection of H. pylori in oral cavity of adult periodontitis patients with plaque and periodontal pocket which atmosphere is grown well H. pylori. We analysed detection rate of H. pylori in saliva and subgingival plaques of 17 adult periodontitis patients without symptoms of gastroduodenal disease by nested PCR. Samples tested comprised saliva and subgingival plaques from central incisor, 1st premolar and 1st molar. H. pylori DNA was not identified in saliva from all patients. The detection rate in subgingival plaque from incisors, premolars and molars was 5.9%, 5.9% and 17.7%, respectively. In conclusion, the dental plaque and periodontal pocket (especially, of molars) in adult periodontitis can be favorable reservoir of H. pylori and may be the source of infection and transmission of H. pylori.
Adult* ; Atmosphere ; Bicuspid ; Chronic Periodontitis* ; Dental Plaque ; DNA ; Gastritis ; Helicobacter pylori* ; Helicobacter* ; Humans ; Incisor ; Molar ; Mouth ; Peptic Ulcer ; Periodontal Pocket ; Polymerase Chain Reaction ; Saliva* ; Stomach Neoplasms

The roots of teeth exposed by gingival recession, may be successfully covered by various type of gingival grafting procedures. Vascularization of the recipient site is an essential determinant of the grafts'survival during the first healing stages. It has been suggested that a procedure by which they stimulate the periosteum presurgically will induce the proliferation of neo-endothelium in the site to be operated. The purpose of this study is to evaluate the variations in the gingival blood flow during 4weeks after periosteal stimulation in patient scheduled to receive gingival grafts and to compare variations in the gingival blood flow between smoker and non-smoker. Laser Doppler Flowmetry(floLAB(R), Moor Instruments Ltd, England ; wave length = 780mm. Max. power =1.6mW) was used to measure the gingival blood flow. 112 sites of 68 male patients (32 smokers and 36 nonsmoker), aged between 23 and 48 years (smoker : 24-44 years, mean=32.6, non-smoker : 23-48 years, mean=28.5) were monitored for the blood flow. Gingival blood flow measured at before periosteal stimulation, 1-, 2-, 3-, and 4-weeks after periosteal stimulation from 10 a.m. to 2 p.m. The difference of blood flow in each measuring time, each measuring site and between smokers and nonsmokers were statistically analyzed by MANOVA. The results were as follows : (1) Blood flow stayed increased for 2 weeks, and then, it was a tendency to decrease(p<0.05). (2) There was no statistically significant difference of blood flow change between smokers and non-smokers. (3) The blood flow at middle site had lower than mesial and distal site during the measuring periods(p<0.05). The present study suggested that blood flow change following peirosteal stimulation was significant difference, thus periosteal stimulation before gingival graft might induce favorable results in gingival recession patient.
England ; Gingival Recession ; Humans ; Male ; Periosteum ; Tooth ; Transplants

Root conditioning has been introduced to dissolve the smear layer, and to aid in detoxification following root planing. It produces surface demineralization, resulting to exposure of dentin collagen fibrils and opening of dentinal tubules. The purpose of the present study was to examine the possibility of obtaining root conditioning effect by using ethylenediamine tetraacetic acid(EDTA) solution instead of low pH etchants such as citric acid and tetracycline hydrochloride(Tc-HCl). Total 48 root specimens(4x5x2mm) were prepared from the mesial and distal root of 24 periodontitisaffected human mandibular molars after scaling and root planing. The specimens were treated with EDTA(17%, neutral pH, Pulpdent?, Pulpdent Co., USA) for 1 min., 2 min., and 3 min., and tetracycline hydrochloride(100mg/ml) for 5 min. using the rubbing technique and the placement technique without rubbing. The dentinal tubules of the specimens were examined under a scanning electron microscopy(JEOL, JSM- 840A, Japan). On the microphotographs taken at x3,000 magnification, the number of identifiable dentinal tubules, opened dentinal tubules, and fully opened dentinal tubules(over 0.9micrometer in diameter) per the unit area(1,067?m2) were counted. And the rate of opened dentinal tubule and the rate of fully opened dentinal tubule were calculated. The difference of those rates among all groups was statistically analyzed by ANOVA and Dunkan test. The results were as follows; 1. In the specimens applied with EDTA, the rate of opened dentinal tubule was not significantly different between each group regardless of application technique and application time(p>0.1). 2. In the specimens applied with EDTA, the rate of fully opened dentinal tubule had tendency to be increased in proportion to application time regardless of application technique. 3. In the specimens applied with EDTA within 2 min., the rate of fully opened dentinal tubule failed to show significant difference between the two techniques(p>0.1). But, in the specimens applied for 3 min., the rate of fully opened dentinal tubule was significantly higher in the specimens applied by the rubbing technique than those by the placement technique(p<0.001). 4. In the specimens applied with Tc-HCl for 5 min., both the rate of opened dentinal tubule(p<0.01) and the rate of fully opened dentinal tubule (p<0.001) were induced significantly higher by the rubbing technique than the placement technique. 5. The rate of fully opened dentinal tubule was significantly higher in both the specimens rubbed for 3 min. with EDTA and the specimens rubbed for 5 min. with Tc-HCl than other groups(p<0.001). But there was no significant difference between the two(p>0.1). The results demonstrate that 17% EDTA solution can replace low pH etchants for root conditioning, and the rubbing technique for at least 3 min. is recommendable.
Humans

It has been believed that the increased release of free oxygen radicals(O2-, H2O2 and OH-) might be one of important factors in the pathogenesis of periodontal diseases. Polymorphonuclear leukocytes(PMNs) constitute the primary host resistance factor against infection. They are prominent cells in both the gingival tissue and gingival sulcus in most forms of periodontal disease. In response to invading microorganisms, the activated PMNs and macrophages generate free oxygen radicals, which play an important role in bacterial killing. The normal production of these free oxygen radicals is vital for the successful resistance of individuals to bacterial infection. However, the enhanced production of reactive oxygen species by accumulating PMNs may be detrimental to the host in certain disease states. This study was performed to evaluate the effect of Tetracycline-HCl(Tc-HCl) on generation of superoxide anion by PMNs. For the present study, 60ml of peripheral venous blood were obtained from systemically healthy subjects by venipuncture in median cubital vein and PMNs were separated by a one-step Ficoll-Hypaque gradient centrifugation method. PMNs were incubated with 1microgram/ml P.gingivalis strain A7436 LPS, 5% serum and Tc-HCl(5, 10, 50 and 100microgram/ml). The superoxide anion analysis was carried out by superoxide dismutase-inhibitable cytochrome C reduction method using Microplate autoreader(BIO-TEK(TM) Instrument Inc.). The difference of superoxide anion generation between control group and Tc-HCl group was statistically analyzed by paired t-test. The superoxide anion generation in the course of time after treatment with Tc-HCl was analyzed by ANOVA, and the superoxide anion generation in the course of time after treatment with various concentrations of Tc-HCl was analyzed by Repeated Measurement test. The results were as follows: 1. Superoxide anion generation by PMNs was significantly decreased by Tc-HCl(p<0.05). 2. There was no statistical significance in the inhibition of superoxide anion generation in the course of time after treatment with various concentrations of Tc-HCl(p>0.05). 3. Superoxide anion generation by PMNs was significantly decreased in the course of incubation time after treatment with Tc-HCl(p<0.05). The results demonstrate that the Tc-HCl inhibit superoxide anion generation by PMNs and the inhibitory effects depend on the exposure time rather than the concentration of Tc-HCl.

Identifying specific factors and/or mechanism regulating development of periodontal tissue will provide important information as to which molecules and cells are required for regulation of periodontal tissue lost as a consequence of disease. The origin and location of cementoblast and osteoblast precursor cells in adult periodontal tissues is not definitely known but it has been suggested that tooth related periodontal ligament may be the source of cementoblasts and the bone-related periodontal ligament for osteoblasts. However, little is known of the molecular mechanism controlling PDL function. PDL-specific protein; PDLs22 had been previously identified as a novel protein isolated from cultured human PDL fibroblasts using subtraction hybridization between human gingival fibroblasts and PDL fibroblasts. The aim of this study was to examine the functional characterization of PDLs22 in differentiation of periodontal ligament, alveolar bone and cementum. Human osteocalcin (OC), osteonectin (ON) and PDLs22 mRNA were detected by reverse transcription polymerase chain reaction (RT-PCR) in primary cell cultures of periodontal ligament fibroblast during mineral nodule formation in vitro. And the localization of PDLs22 in rat tissues was detected by polyclonal antibody against PDLs22 by means of immunohistochemical staining. The results were as follows: 1. PDL cells were capable of producing mineral-like nodules in vitro. 2. PDLs22 mRNA was expressed in the initial stages whereas it was not expressed in the calcification stage, during mineral nodule formation of PDL cells in vitro. 3. PDLs22 protein was expressed in external dental epithelium and stellate reticulum during crown formation stage, and was continued in external dental epithelium of Hertwig's epithelial sheath. Also PDLs22 protein was strongly expressed in the bone and cementum-related side of the PDL and weakly expressed in the middle of PDL. In the developing bone, PDLs22 protein is only expressed in preosteoblast not osteocyte and osteoblast. The results suggest PDLs22 is important mediator of epithelial-mesenchymal reaction in development of PDL, alveolar bone and cementum and is related to initial differentiation of cementum and alveolar bone.
Adult ; Animals ; Crowns ; Dental Cementum* ; Epithelium ; Fibroblasts ; Humans ; Osteoblasts ; Osteocalcin ; Osteocytes ; Osteonectin ; Periodontal Ligament* ; Polymerase Chain Reaction ; Primary Cell Culture ; Rats ; Reticulum ; Reverse Transcription ; RNA, Messenger ; Tooth

Crowns ; Finite Element Analysis ; Mandible ; Prostheses and Implants

Extracellular matrix component is degraded by enzymes of thematrix metalloproteinases(MMPs). MMPs are produced by both hemopoietic and structural cells. Increased activity of MMP-3 in periodontium is strongly associated with inflammatory periodontal disease. The purpose of the present study was to determine the effect of tetracycline analogues on the activity of MMP-3. Tetracycline-HCl, doxycycline-HCl, and minocycline-HCl were applied to huamn gingival fibroblasts at various concentrations of 10, 25, 50, 100, 200microgram/ml, and 1 hour later IL-1beta of 25ng/ml was added. After incubation for 24 hours the cells were reacted by enzyme-linked immunosorbent assay using proMMP-3 ELISA kit. The optical density was measured by microwell plate reader at 450nm. The relative activity of MMP-3 was calculated as the percentage of the optical density of each experimental group to that of the control. The difference of the optical density and the relative activity of MMP-3 between the experimental groups and the control wasstatistically analyzed by one way ANOVA. The results were as follows: 1. Tetracycline-HCl showed the tendency to inhibit the activity of MMP-3 at the concentration lower than 25 microgram/ml, but increased significantly the activity of MMP-3 at the concentration of 200microgram/ml(p<0.05). 2. Doxycycline-HCl inhibited significantly the activity of MMP-3 at the concentration lower than 100microgram/ml, but increased significantly the activity of MMP-3 at the concentration of 200microgram/ml(p<0.05). 3. Minocycline-HCl inhibited the activity of MMP-3 at the concentration in the range of 10 to 200microgram/ml. Within the limit of the present study, the above results suggested that the low concentration of tetracycline analogues could inhibit the activity of MMP-3 induced by IL-1beta in human gingival fibroblasts.
Enzyme-Linked Immunosorbent Assay ; Extracellular Matrix ; Fibroblasts* ; Humans ; Interleukin-1beta ; Matrix Metalloproteinases ; Periodontal Diseases ; Periodontium ; Tetracycline*

Stress transfer to the surrounding tissues is one of the factors involved in the design of dental implants. Unfortunately, insufficient data are available for stress transfer within the regenerated bone surrounding dental implants. The purpose of this study was to investigate the concentration of stresses within the regenerated bone surrounding the implant using three-dimensional finite element stress analysis method. Stress magnitude and contours within the regenerated bone were calculated. The 3.75*10-mm implant (3i, USA) was used for this study and was assumed to be 100% osseointegrated, and was placed in mandibular bone and restored with a cast gold crown. Using ANSYS software revision 6.0, a program was written to generate a model simulating a cylindrical block section of the mandible 20 mm in height and 10 mm in diameter. The present study used a fine grid model incorporating elements between 165,148 and 253,604 and nodal points between 31,616 and 48,877. This study was simulated loads of 200N at the central fossa (A), at the outside point of the central fossa with resin filling into screw hole (B), and at the buccal cusp (C), in a vertical and 30degree lateral loading, respectively. The results were as follows; 1. In case the regenerated bone (bone quality type IV) was surrounded by bone quality type I and II, stresses were increased from loading point A to C in vertical loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, concentrated on the top of the cylindrical collar loading point B and C in vertical loading. And, In case the regenerated bone (bone quality type IV) was surrounded by bone quality type III, stresses were increase from loading point A to C in vertical loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, B and C in vertical loading. 2. In case the regenerated bone (bone quality type IV) was surrounded by bone quality type I and II, stresses were decreased from loading point A to C in lateral loading. Stresses according to the depth of regenerated bone were concentrated on the top of the cylindrical collar in loading point A and B, distributed along the implant evenly in loading point C in lateral loading. And, In case the regenerated bone (bone quality type IV) was surrounded by bone quality type III, stresses were decreased from loading point A to C in lateral loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, B and C in lateral loading. In summary, these data indicate that both bone quality surrounding the regenerated bone adjacent to implant fixture and load direction applied on the prosthesis could influence concentration of stress within the regenerated bone surrounding the cylindrical type implant fixture.
Crowns ; Dental Implants ; Finite Element Analysis* ; Mandible ; Prostheses and Implants