Evaluation of the mechanical properties and clinical efficacy of biphasic calcium phosphate-added collagen membrane in ridge preservation

Purpose@#This study aimed to evaluate the biocompatibility and the mechanical properties of ultraviolet (UV) cross-linked and biphasic calcium phosphate (BCP)-added collagen membranes and to compare the clinical results of ridge preservation to those obtained using chemically cross-linked collagen membranes. @*Methods@#The study comprised an in vitro test and a clinical trial for membrane evaluation. BCPadded collagen membranes with UV cross-linking were prepared. In the in vitro test, scanning electron microscopy, a collagenase assay, and a tensile strength test were performed. The clinical trial involved 14 patients undergoing a ridge preservation procedure. All participants were randomly divided into the test group, which received UV cross-linked membranes (n=7), and the control group, which received chemically cross-linked membranes (n=7). BCP bone substitutes were used for both the test group and the control group. Cone-beam computed tomography (CBCT) scans were performed and alginate impressions were taken 1 week and 3 months after surgery. The casts were scanned via an optical scanner to measure the volumetric changes. The results were analyzed using the nonparametric Mann-Whitney U test. @*Results@#The fastest degradation rate was found in the collagen membranes without the addition of BCP. The highest enzyme resistance and the highest tensile strength were found when the collagen-to-BCP ratio was 1:1. There was no significant difference in dimensional changes in the 3-dimensional modeling or CBCT scans between the test and control groups in the clinical trial (P>0.05). @*Conclusions@#The addition of BCP and UV cross-linking improved the biocompatibility and the mechanical strength of the membranes. Within the limits of the clinical trial, the sites grafted using BCP in combination with UV cross-linked and BCP-added collagen membranes (test group) did not show any statistically significant difference in terms of dimensional change compared with the control group.

Evaluation of the mechanical properties and clinical efficacy of biphasic calcium phosphate-added collagen membrane in ridge preservation

Purpose@#This study aimed to evaluate the biocompatibility and the mechanical properties of ultraviolet (UV) cross-linked and biphasic calcium phosphate (BCP)-added collagen membranes and to compare the clinical results of ridge preservation to those obtained using chemically cross-linked collagen membranes. @*Methods@#The study comprised an in vitro test and a clinical trial for membrane evaluation. BCPadded collagen membranes with UV cross-linking were prepared. In the in vitro test, scanning electron microscopy, a collagenase assay, and a tensile strength test were performed. The clinical trial involved 14 patients undergoing a ridge preservation procedure. All participants were randomly divided into the test group, which received UV cross-linked membranes (n=7), and the control group, which received chemically cross-linked membranes (n=7). BCP bone substitutes were used for both the test group and the control group. Cone-beam computed tomography (CBCT) scans were performed and alginate impressions were taken 1 week and 3 months after surgery. The casts were scanned via an optical scanner to measure the volumetric changes. The results were analyzed using the nonparametric Mann-Whitney U test. @*Results@#The fastest degradation rate was found in the collagen membranes without the addition of BCP. The highest enzyme resistance and the highest tensile strength were found when the collagen-to-BCP ratio was 1:1. There was no significant difference in dimensional changes in the 3-dimensional modeling or CBCT scans between the test and control groups in the clinical trial (P>0.05). @*Conclusions@#The addition of BCP and UV cross-linking improved the biocompatibility and the mechanical strength of the membranes. Within the limits of the clinical trial, the sites grafted using BCP in combination with UV cross-linked and BCP-added collagen membranes (test group) did not show any statistically significant difference in terms of dimensional change compared with the control group.

Adjunctive hyperbaric oxygen therapy for irradiated rat calvarial defects

PURPOSE: The aim of this study was to conduct a histologic evaluation of irradiated calvarial defects in rats 4 weeks after applying fibroblast growth factor-2 (FGF-2) with hyaluronan or biphasic calcium phosphate (BCP) block in the presence or absence of adjunctive hyperbaric oxygen (HBO) therapy. METHODS: Twenty rats were divided into HBO and non-HBO (NHBO) groups, each of which was divided into FGF-2 and BCP-block subgroups according to the grafted material. Localized radiation with a single 12-Gy dose was applied to the calvaria of rats to simulate radiotherapy. Four weeks after applying this radiation, 2 symmetrical circular defects with a diameter of 6 mm were created in the parietal bones of each animal. The right-side defect was filled with the materials mentioned above and the left-side defect was not filled (as a control). All defects were covered with a resorbable barrier membrane. During 4 weeks of healing, 1 hour of HBO therapy was applied to the rats in the HBO groups 5 times a week. The rats were then killed, and the calvarial specimens were harvested for radiographic and histologic analyses. RESULTS: New bone formation was greatest in the FGF-2 subgroup, and improvement was not found in the BCP subgroup. HBO seemed to have a minimal effect on new bone formation. There was tendency for more angiogenesis in the HBO groups than the NHBO groups, but the group with HBO and FGF-2 did not show significantly better outcomes than the HBO-only group or the NHBO group with FGF-2. CONCLUSIONS: HBO exerted beneficial effects on angiogenesis in calvarial defects of irradiated rats over a 4-week healing period, but it appeared to have minimal effects on bone regeneration. FGF-2 seemed to enhance new bone formation and angiogenesis, but its efficacy appeared to be reduced when HBO was applied.

Development of an experimental model for radiation-induced inhibition of cranial bone regeneration / 대한악안면성형재건외과학회지

BACKGROUND: Radiation therapy is widely employed in the treatment of head and neck cancer. Adverse effects of therapeutic irradiation include delayed bone healing after dental extraction or impaired bone regeneration at the irradiated bony defect. Development of a reliable experimental model may be beneficial to study tissue regeneration in the irradiated field. The current study aimed to develop a relevant animal model of post-radiation cranial bone defect. METHODS: A lead shielding block was designed for selective external irradiation of the mouse calvaria. Critical-size calvarial defect was created 2 weeks after the irradiation. The defect was filled with a collagen scaffold, with or without incorporation of bone morphogenetic protein 2 (BMP-2) (1 μg/ml). The non-irradiated mice treated with or without BMP-2-included scaffold served as control. Four weeks after the surgery, the specimens were harvested and the degree of bone formation was evaluated by histological and radiographical examinations. RESULTS: BMP-2-treated scaffold yielded significant bone regeneration in the mice calvarial defects. However, a single fraction of external irradiation was observed to eliminate the bone regeneration capacity of the BMP-2-incorporated scaffold without influencing the survival of the animals. CONCLUSION: The current study established an efficient model for post-radiation cranial bone regeneration and can be applied for evaluating the robust bone formation system using various chemokines or agents in unfavorable, demanding radiation-related bone defect models.

Periodontal inflamed surface area as a novel numerical variable describing periodontal conditions

PURPOSE: A novel index, the periodontal inflamed surface area (PISA), represents the sum of the periodontal pocket depth of bleeding on probing (BOP)-positive sites. In the present study, we evaluated correlations between PISA and periodontal classifications, and examined PISA as an index integrating the discrete conventional periodontal indexes. METHODS: This study was a cross-sectional subgroup analysis of data from a prospective cohort study investigating the association between chronic periodontitis and the clinical features of ankylosing spondylitis. Data from 84 patients without systemic diseases (the control group in the previous study) were analyzed in the present study. RESULTS: PISA values were positively correlated with conventional periodontal classifications (Spearman correlation coefficient=0.52; P<0.01) and with periodontal indexes, such as BOP and the plaque index (PI) (r=0.94; P<0.01 and r=0.60; P<0.01, respectively; Pearson correlation test). Porphyromonas gingivalis (P. gingivalis) expression and the presence of serum P. gingivalis antibodies were significant factors affecting PISA values in a simple linear regression analysis, together with periodontal classification, PI, bleeding index, and smoking, but not in the multivariate analysis. In the multivariate linear regression analysis, PISA values were positively correlated with the quantity of current smoking, PI, and severity of periodontal disease. CONCLUSIONS: PISA integrates multiple periodontal indexes, such as probing pocket depth, BOP, and PI into a numerical variable. PISA is advantageous for quantifying periodontal inflammation and plaque accumulation.

Microgrooves on titanium surface affect peri-implant cell adhesion and soft tissue sealing; an in vitro and in vivo study

PURPOSE: With the significance of stable adhesion of alveolar bone and peri-implant soft tissue on the surface of titanium for successful dental implantation procedure, the purpose of this study was to apply microgrooves on the titanium surface and investigate their effects on peri-implant cells and tissues. METHODS: Three types of commercially pure titanium discs were prepared; machined-surface discs (A), sandblasted, large-grit, acid-etched (SLA)-treated discs (B), SLA and microgroove-formed discs (C). After surface topography of the discs was examined by confocal laser scanning electron microscopy, water contact angle and surface energy were measured. Human gingival fibroblasts (hGFs) and murine osteoblastic cells (MC3T3-E1) were seeded onto the titanium discs for immunofluorescence assay of adhesion proteins. Commercially pure titanium implants with microgrooves on the coronal microthreads design were inserted into the edentulous mandible of beagle dogs. After 2 weeks and 6 weeks of implant insertion, the animal subjects were euthanized to confirm peri-implant tissue healing pattern in histologic specimens. RESULTS: Group C presented the lowest water contact angle (62.89+/-5.66 theta), highest surface energy (45+/-1.2 mN/m), and highest surface roughness (Ra=22.351+/-2.766 microm). The expression of adhesion molecules of hGFs and MC3T30E1 cells was prominent in group C. Titanium implants with microgrooves on the coronal portion showed firm adhesion to peri-implant soft tissue. CONCLUSIONS: Microgrooves on the titanium surface promoted the adhesion of gingival fibroblasts and osteoblastic cells, as well as favorable peri-implant soft tissue sealing.

A case report about the reconstruction procedures of the previously failed cylinderical implants site using distraction osteogenesis

We report the eventually successful treatment of a huge bone defect and peri-implantitis following reconstruction of a previously failed intra-mobile cylinder implant system (IMZ) implant site using distraction osteogenesis (DO). In the anterior mandible, two IMZ implants failed and surgical debridement was performed in accordance to the patient's needs. Thereafter, mobility and suppuration were decreased and the patient visited the dental clinic on a regular basis for oral health maintenance. However, the inflammation did not resolve, and the bone destruction around the implants progressed for 4 years. Finally, the implants failed and a severe bone defect remained after implant removal. To reconstruct the bone defects, we attempted bone graft procedures. Titanium mesh was unsuccessfully used to obtain bone volume regeneration. However, DO subsequently was used to obtain sufficient bone volume for implant placement. The new implants were then installed, followed by prosthetic procedures. In conclusion, progression of peri-implantitis could not be arrested despite surgical intervention and repeated maintenance care for 3 years. Reconstruction of the peri-implantitis site was complicated due to its horizontal and vertical bone defects. Lesions caused by implant failure require an aggressive regenerative strategy, such as DO. DO was successful in reconstruction of a peri-implantitis site that was complicated due to horizontal and vertical bone defects.

Association Between Halitosis Diagnosed by a Questionnaire and Halimeter and Symptoms of Gastroesophageal Reflux Disease

BACKGROUND/AIMS: The relationship between halitosis and gastroesophageal reflux disease (GERD) remains controversial. The aim of this study was to investigate an association between subjective and objective halitosis and GERD. METHODS: The subjects were enrolled from participants who visited a health promotion center at Seoul National University Bundang Hospital. For diagnosis of halitosis, a questionnaire was requested, and volatile sulfur compounds (VSCs) were measured by Halimeter. Self-conscious halitosis was defined as halitosis perceived by himself or herself. Informed halitosis was defined as halitosis perceived by others. Objective halitosis was defined when mean VSCs values were > 100 parts per billion. GERD was defined based on a questionnaire and endoscopy, including erosive esophagitis and non-erosive reflux disease (NERD). RESULTS: A total of 54 subjects (male:female = 33:21) with mean age of 46.0 +/- 11.4 years were analyzed. The mean VSCs values were not significantly different between presence and absence of self-conscious halitosis (P = 0.322), but significantly different between presence and absence of informed halitosis (P = 0.021). Informed halitosis was associated with objective halitosis (P = 0.039). GERD, erosive esophagitis and NERD did not correlate with objective halitosis (P = 0.556, 0.206 and 0.902, respectively). In multivariable analysis, the relationship between objective halitosis and GERD symptoms including chest pain, heart burn, acid regurgitation, epigastric pain, hoarseness, globus sensation and coughing was not significant. Besides, GERD was not associated with self-conscious halitosis, informed halitosis and objective halitosis, respectively. CONCLUSIONS: GERD might not be associated with self-conscious, informed halitosis and objective halitosis indicated by Halimeter results. Informed halitosis could be correlated with objective halitosis determined by the Halimeter.

Enhanced bone morphogenic protein adenoviral gene delivery to bone marrow stromal cells using magnetic nanoparticle

OBJECTIVES: This study investigated the question of whether adenoviral magnetofection can be a suitable method for increasing the efficacy of gene delivery into bone marrow stromal cell (BMSC) and for generation of a high level of bone morphogenic protein (BMP) secretion at a minimized viral titer. MATERIALS AND METHODS: Primary BMSCs were isolated from C57BL6 mice and transduced with adenoviral vectors encoding beta galactosidase or BMP2 and BMP7. The level of BMP secretion, activity of osteoblast differentiation, and cell viability of magnetofection were measured and compared with those of the control group. RESULTS: The expression level of beta galactosidase showed that the cell transduction efficiency of AdLacZ increased according to the increased amount of magnetic nanoparticles. No change in cell viability was observed after magnetofection with 2 microL of magnetic nanoparticle. Secretion of BMP2 or BMP7 was accelerated after transduction of AdBMP2 and 7 with magnetofection. AdBMP2 adenoviral magnetofection resulted in up to 7.2-fold higher secretion of BMP2, compared with conventional AdBMP2-transduced BMSCs. Magnetofection also induced a dramatic increase in secretion of BMP7 by up to 10-fold compared to the control. Use of only 1 multiplicity of infection (moi) of magnetofection with adenoviral transduction of AdBMP2 or AdBMP7 resulted in significantly higher transgene expression compared to 20 moi of conventional adenoviral transduction. CONCLUSION: Magnetic particle-mediated gene transudation is a highly efficient method of gene delivery to BMSCs. Magnetofection can lower the amount of viral particles while improving the efficacy of gene delivery.

Corrigendum: Enhanced bone morphogenic protein adenoviral gene delivery to bone marrow stromal cells using magnetic nanoparticle

This correction is being published to correct the author's name and the affiliation.

Effects of Inhibition of Endogenous Nitric Oxide System on Regional Myocardial Function and Systemic Hemodynamics in Anesthetized Dogs / 대한마취과학회지

BACKGROUND: The present study was aimed (1) to assess the effects of nitric oxide (NO) synthesis inhibitor on regional myocardial function and systemic and pulmonary hemodynamics; (2) to determine whether the blockade of the cyclo-oxygenase (COX) pathway modifies these effects on the variables, and (3) to investigate the mechanism of cardiac depression following NO synthesis inhibition in an open-chest canine model. METHODS: Twenty-five dogs of either sex were acutely instrumented under 1.6% ethrane anesthesia to measure aortic, pulmonary arterial and left ventricular pressure, pulmonary (cardiac output) and left circumflex coronary flow, and subendocardial segment length. NG-nitro-L-arginine methyl ester (L- NAME) at doses of 0.3, 1.0, 3.0, or 10.0 mg/kg i.v. was administered alone (control dogs, n = 10) or in the presence of COX inhibitor, indomethacin (10 mg/kg i.v., n = 10). Seven dogs (n = 7) received phenylephrine at doses of 0.1, 0.3, 1.0, or 3.0 microgram/kg/min i.v. to compare its hemodynamic effects with those of L-NAME. The preload recruitable stroke work slope (Mw) and percent systolic shortening (%SS) as an index of regional myocardial contractility, and the maximum segment lengthening rate (dL/dt max) and percent post-systolic shortening (%PSS) as an index of regional diastolic function, were evaluated. RESULTS: L-NAME dose-dependantly attenuated both regional systolic (Mw and %SS) and diastolic functions (dL/dt max and %PSS), whereas it caused an increase of coronary flow. L-NAME dose- dependently increased systemic blood pressure and vascular resistance as well as pulmonary arterial pressure and vascular resistance. L-NAME also reduced cardiac and stroke volume indices. Pretreatment with indomethacin did not affect the regional myocardial and systemic hemodynamic responses to L-NAME, but did blunt the coronary flow and pulmonary pressure responses. The magnitude of decreases in cardiac and stroke volume indices and Mw was greater with L-NAME than with phenylephrine (P <0.05), despite the comparable blood pressure increases. CONCLUSIONS:These results suggest (1) that NO plays a significant role in cardiac function as well as in systemic and pulmonary but not coronary, vasomotor activities, and (2) that COX products are involved in pulmonary hemodynamic responses to NO synthesis inhibition. It is also suggested that the decline in cardiac output following the NO synthesis inhibition results from a direct myocardial depressant effect of the drug.

The effect of smoking on the healing response following flap debridement surgery / 대한치주과학회지

The ultimate goal of periodontal therapy is the regeneration of periodontal tissue which has been lost due to destructive periodontal disease. Various periodontal procedures have been used throughout the years in an attempt to reestablish attachment of periodontal tissues to root surfaces affected by periodontitis. Flap debridement surgery has been demonstrated to be a successful procedure in gaining the probing attachment level and reducing probing depth. A tendency towards impaired wound healing following periodontal procedures in smokers has been clinically documented. But, previous clinical studies on healing response in smokers are based on a retrospective design. The purpose of this study was to evaluate the treatment outcome following flap debridement surgery in smokers compared to nonsmokers. 25 patients with moderate to advanced periodontitis were included for study. Among these patients, 13 patients were smokers, and 12 patients were nonsmokers. Mucoperiosteal flap was raised with the sulcular incision. No antibiotic treatment was administered postsurgery. The patients was recalled at monthly intervals during a period of 6 months following the surgery. The patients were received supragingival scaling and oral hygiene reinforcement. All the recordings, including modified O'Leary plaque control record, bleeding on probing! probing pocket depth, probing attachment level, were recorded, presurgery and 6 months postsurgery. The changes of all the recordings at 6 months after flap debridement surgery revealed the following results: 1. PI on all the dentitions and surgical sites showed no statistical significance between smokers and nonsmokers at presurgery. But, smokers demonstrated a significantly lower % of PI than nonsmokers at 6 months postsurgery. 2. Smokers demonstrated a greater % of BOP sites than nonsmokers on the surgical sites and all the dentitions, presurgery and 6 months postsurgery. But, there was no statistical significance between two groups. 3. Smokers exhibited significantly less reduction of probing depth in the 3 mm or less probing pocket depth(PPD) group, 6mm or more PPD group and total PPD group when compared to nonsmokers at 6 months postsurgery. 4. Smokers exhibited significantly less gain of probing attachment level(PAL) in the 3mm or less PPD group, 6 mm or more PPD group and total PPD group when compared to nonstmokers at 6 months postsurgery.

The Effect of Preanesthetic Administration of Crystalloid for Prevention of Spinal Anesthesia-Induced Hypotension / 대한마취과학회지

BACKGREOUND: Despite many advantages of spinal anesthesia, hypotension after spinal anesthesia is a common complication. The practice of routine preemptive infusion of crystalloid before spinal anesthesia has been widespread acceptance. But the value of this practice has recently been questioned. This study was designed to determine whether preoperative administration of crystalloid decrease the incidence of hypotension after spinal anesthesia. METHODS: Thirty ASA I and II patients for elective lower extremities operations under spinal anesthesia were randomized to receive either 500 ml Ringer's lactate solution prior to induction of spinal anesthesia (group I) or no prehydration (group II). Hypotension was defined as a 30% decrease from baseline systolic blood pressure or systolic 70% of baseline, systolic blood pressure and heart rate were not significantly different between both groups. CONCLUSIONS: We conclude that, in normovolemic adult patients undergoing elective lower extremities surgery, an intravenous infusion of 500 ml of Ringer's lactate solution is ineffective in preventing hypotension during spinal anesthesia.

The Postoperative Analgesic Effects of Epidural Clonidine during General Anesthesia / 대한마취과학회지

BACKGROUND: Epidurally administered clonidine produces analgesia by an alpha 2-adrenergic mechanism and may provide postoperative analgesia without nausea, pruritus and respiratory depression associated with opioid administration. Many studies have shown the beneficial effects of epidural clonidine in postoperative pain management. Pre-administered epidural analgesic agent before the skin incision may prevent the nociceptive input. We provided the pre-emptive analgesia and compared the postoperative analgesic effects of epidural clonidine when used as the sole analgesic agent with epidural fentanyl and epidural bupivacaine. METHODS: Thirty-nine gynecologic patients, ASA physical status 1, 2, undergoing elective lower abdominal surgery under general anesthesia, were studied. They were not taking any premedications. Before anesthesia, an epidural catheter was inserted at the L2~3 interspace. Patients were divided into 3 groups randomly. Group 1 received 0.125% bupivacaine 20 ml through the epidural catheter, group 2 received 100 microgram fentanyl in normal saline 20 ml, and group 3 received 150 microgram clonidine in normal saline 20 ml. During the operation, we recorded the vital signs and side effects. Just before suturing peritoneum, we injected the corresponding drugs on individual groups through the epidural catheter. In the recovery room, the postoperative analgesia was assessed by VAS (visual analogue scale). Vital signs, sedation score and side effects were also checked. RESULTS: VAS and systolic blood pressure were significantly lower in group 3 than group 1 or group 2 at the recovery room. The diastolic blood pressure, heart rate and sedation score were not significantly different between three groups at the recovery room. Also the vital signs during the operation were notsignificantly different between three groups. The incidence of hypotension was 3 out of 13 in group 3 and 1 out of 13 in group 1. CONCLUSION: Epidural bolus clonidine 150 microgram produces more profound and longer postoperative analgesic effects than fentanyl 100 microgram or 0.125% bupivacaine at the lower abdominal surgery. But hypotension may occur more frequently. So, if we select the patient cautiously, epidural clonidine is a good alternative analgesic agent for the postoperative analgesia.

Effect of Lidocaine on Pain Caused by Intravenous Injection of Diazepam ( Valium ) / 대한마취과학회지

Diazepam containing solvents such as propylene glycol & ethanol, causes pain on intravenous injection in most patients. The purpose of this study was to know the effect of lidocaine to reduce pain on iv injection of diazepam. Eighty patients were allocated four groups according to the lidocaine dosage & method of lidocaine administration; control group, diazepam 10 mg with no lidocaine, group 1, diazepam 10 mg with lidocaine 5 mg mixture; group 2, diazepam 10 mg with lidocaine 10 mg mixture, and group 3, diazepam 10 mg preceding lidocaine 10 mg under tourniquet. Results in this study showed that diazepam 10 mg with lidocaine 10 mg mixture(group 2) and diazepam with preceding lidocaine 10 mg under tourniquet(group 3) significantly reduced the incidence of pain without untoward effects of lidocaine on the cardiovascular system.