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Biomedical subjects

Seong-Ho Choi

Publications and source records attributed to Seong-Ho Choi.

At least 19 recordsLinked to original sources
PubMed2006

Phase II study of capecitabine and cisplatin in previously untreated advanced biliary tract cancer.

BACKGROUND: Biliary tract cancer is one of the most aggressive and chemotherapy-refractory tumors. Although only curative treatment modality is surgery, most patients are not suitable for surgery due to advanced stage of the disease at diagnosis. Thus most patients with biliary tract cancer are possible candidates for palliative chemotherapy. The standard chemotherapeutic regimen is still to be defined, however. We performed a phase II study of combination chemotherapy with capecitabine and cisplatin in these patients to evaluate efficacy and toxicity of the regimen. METHODS: Patients with previously untreated metastatic, recurrent, or inoperable biliary tract cancer were enrolled. Eligible patients were screened as following: (1) histologically confirmed, (2) age between 18 and 75 years, (3) at least one measurable lesion according to RECIST criteria, (4) ECOG performance status <or=2, (5) a life expectancy of at least 3 months, and (6) adequate laboratory values. Patients received capecitabine (2,500 mg/m2/day, days 1 to 14) and cisplatin (60 mg/m2, day 1) every 3 weeks. Response was assessed for every two cycles of chemotherapy and treatment was stopped when tumor had progressed or stable with no further response. RESULTS: Thirty-two patients were enrolled, 20 (62.5%) were male and 12 (37.5%) were female and the median age was 54 years (33-71 years). Fifteen patients (46.9%) had gallbladder cancer, 13 (40.6%) had intrahepatic cholangiocarcinoma, and 4 (12.5%) had extrahepatic biliary cancer. The most frequent metastatic sites were lymph nodes (20/32, 62.5%) and liver (28/32, 56.3%). No complete response was observed and partial response was observed in 13/32 patients. By the intent-to-treat analysis, the overall response rate was 40.6% (95% CI, 23.7-59.4) with 0 CR and 13 PRs. Stable disease was observed in 3 patients (9.4%), and 11 patients (34.4%) had progressive disease. The median time to progression was 3.5 months (95% CI, 1.3-5.8), and the median overall survival was 12.4 months (95% CI, 6.3-18.5) after the median follow-up duration of 9.5 months (4.8-26.1 months). A total of 108 cycles of chemotherapy was delivered. Grade 3 hematologic toxicities included neutropenia (5, 15.6%), anemia (1, 3.1%), and thrombocytopenia (1, 3.1%) per patient, and no grade 4 hematologic toxicities were observed. Grade 3 non-hematologic toxicities included hyperbilirubinemia (2, 6.3%), increase of alkaline phosphatase (2, 6.3%), hand-foot syndrome (2, 6.3%), anorexia, and diarrhea (1, 3.1%) per patient, respectively. There was no treatment-related death. CONCLUSION: The combination chemotherapy of capecitabine and cisplatin demonstrated a promising antitumor activity with mild toxicity profile in patients with advanced biliary tract cancer.

Adult↗
PubMed2006

Purification and characterization of a biosurfactant produced by Pseudomonas sp. G11 by asymmetrical flow field-flow fractionation (AsFlFFF).

Three hundred and thirty two bacterial colonies were isolated from soil contaminated by an oil spill. All the bacteria were cultured in a liquid medium individually, and the surface tensions of the media were compared. The bacterium whose culture medium had the lowest surface tension was identified as Pseudomonas sp. G11. A biosurfactant was produced by cultivation of the Pseudomonas sp. G11 in the LB media. For extraction of the biosurfactant, two solvent systems were used (n-hexane and a 2:1 (v/v) mixture of chloroform/MeOH), and the results were compared. Various experimental conditions (solvent composition, flow rate, etc.) were tested to optimize the analysis of the biosurfactant by asymmetrical flow field-flow fractionation (AsFlFFF). The biosurfactant was successfully separated from the culture medium by AsFlFFF when pure water was used as the carrier. From the retention data, the hydrodynamic diameter (dH) and molecular weight (M) of the biosurfactant were determined by AsFlFFF. The molecular weight was determined by using pullulans as the calibration standards. The dH and M were 49 nm and 2.3 x 10(5) Da when extracted with n-hexane, and 39 nm and 1.13 x 10(5) Da when extracted with the 2:1 mixture of chloroform/MeOH, respectively.

Calibration↗
PubMed2006

The effect of a fibrin-fibronectin/beta-tricalcium phosphate/recombinant human bone morphogenetic protein-2 system on bone formation in rat calvarial defects.

In spite of good prospects for bone morphogenetic proteins (BMP) applications, an ideal carrier system for BMPs has not yet been identified. The purpose of this study was to evaluate the osteogenic effect of a fibrin-fibronectin sealing system (FFSS) combined with beta-tricalcium phosphate (beta-TCP) as a carrier system for recombinant human bone morphogenetic proteins (rhBMP-2) in the rat calvarial defect model. Eight-millimeter critical-size calvarial defects were created in 100 male Sprague-Dawley rats. The animals were divided into five groups of 20 animals each. The defects were treated with rhBMP-2/FFSS, rhBMP-2/FFSS/beta-TCP, FFSS and FFSS/beta-TCP carrier control or were left untreated as a sham-surgery control. Defects were evaluated by histologic and histometric parameters following a 2- and 8-week healing interval (10 animals/group/healing intervals). The FFSS/beta-TCP carrier group was significantly greater in new bone area at 2 weeks (p<0.05) and new tissue area at 2 and 8 weeks (p<0.01) relative to the FFSS carrier group. New bone and new tissue area in the rhBMP-2/FFSS/beta-TCP group were significantly greater than in the rhBMP-2/FFSS group at 8 weeks (p<0.01). On histologic observation, FFSS remnants were observed at 2 weeks, but by 8 weeks, the FFSS appeared to be completely resorbed. rhBMP-2 combined with FFSS/beta-TCP produced significantly more new bone and new tissue formation in this calvarial defect model. In conclusion, FFSS/beta-TCP may be considered as an available carrier for rhBMP-2.

Animals↗
PubMed2006

A Phase II study of gemcitabine and cisplatin in advanced biliary tract cancer.

BACKGROUND: The authors performed a Phase II study of combination chemotherapy with gemcitabine and cisplatin in patients with inoperable biliary tract cancer to evaluate efficacy and toxicity of this combination. In addition, the correlation between the CA 19-9 response and clinical outcome was analyzed. METHODS: The eligibility criteria for this study were 1) histologically or cytologically confirmed inoperable biliary tract cancer in patients with metastatic or recurrent disease; 2) age between 18 and 70 years; 3) at least 1 measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria; 4) an Eastern Cooperative Oncology Group (ECOG) performance status < or = 2; 5) a life expectancy of at least 3 mos; and 6) adequate bone marrow, hepatic, and renal function. The patients received gemcitabine (1250 mg/m(2), Days 1 and 8) and cisplatin (60 mg/m(2), Day 1) every 3 weeks. Tumor response was assessed by RECIST criteria every 2 cycles of chemotherapy. Treatment was continued until progression of disease was documented. RESULTS: Twenty-nine patients were enrolled. The median age of these patients was 52 years (range, 37 to 69 yrs), and the median ECOG performance status was 1. No complete response was observed, and 10 of 29 patients had partial responses. The overall response rate was 34.5% (95% confidence interval [CI], 17.9-54.3) for the intent-to-treat analysis. Stable disease was observed in 4 (13.8%) patients and progressive disease in 13 (44.8%) patients. The median follow-up time was 10.0 months (95% CI, 7.2-12.8). The median time to progression (TTP) was 3.0 months (95% CI, 2.12-3.88), and the median overall survival was 11 months (95% CI, 5.49-16.5). Although these results showed a better response rate (57.1 % vs. 27.3%) and survival (12 vs. 10 mos) in patients with a decline in CA 19-9 of at least 25%, these data were statistically not significant. In addition, there was a significant positive correlation between the increment in CA 19-9 values and tumor progression as determined with RECIST criteria (r = 0.96, P < 0.01). However, there was no definite correlation between the CA 19-9 response and the response according to RECIST criteria (P = 0.087). National Cancer Institute (NCI) common toxicity criteria (CTC) Grade 3 or 4 hematologic toxicities included neutropenia in 4 (14%) patients and anemia in 1 (3%) patient. Two of 4 patients with Grade 3 or 4 neutropenia had febrile episodes (7%) and required hospital admissions. NCI-CTC Grade 3 or 4 nonhematologic toxicity included nausea in 1 (3%) patient. There were no treatment-related deaths. CONCLUSION: The combination chemotherapy with gemcitabine and cisplatin in inoperable biliary tract cancer was tolerable for most patients and showed modest response rates. The role of CA 19-9 monitoring as a surrogate biomarker in patients with BTC treated with gemcitabine chemotherapy should be further investigated.

Adenocarcinoma↗
PubMed2006

Missing effect of glutamine supplementation on the surgical outcome after pancreaticoduodenectomy for periampullary tumors: a prospective, randomized, double-blind, controlled clinical trial.

BACKGROUND: The effect of glutamine (Gln) supplementation in patients undergoing a major operation has not been conclusively established. This study was designed to elucidate the effect of Gln supplementation on the surgical outcome after a pancreaticoduodenectomy (PD) for periampullary tumors. METHODS: A prospective, randomized, double-blind, and controlled clinical trial was undertaken for patients who underwent a classical PD or a pylorus-preserving PD for periampullary tumors. The Gln and control groups received isonitrogenous amino acid, with a 0.2 g/kg per day Gln regimen administered to the Gln group. The surgical outcome was compared in light of length of postoperative hospital stay, nutritional and chemical profiles, and complication rate between the Gln and control groups. RESULTS: Sixty of the consecutive 143 patients who were admitted to undergo operation for periampullary tumors were enrolled in our study; 32 were in the Gln group and 28 in the control group. The two groups were comparable prior to and during the operation. The median length of the postoperative hospital stay and the postoperative nutritional and chemical profiles were not different between two groups. The overall and PD-related complication rates of the Gln group (37.5% and 25.0%) and the control group (28.6% and 14.3%) were not statistically different. CONCLUSIONS: No significant beneficial effect of Gln supplementation with a low-dose parenteral regimen was demonstrated on the surgical outcome after a PD for periampullary tumors. Therefore, we should be prudent in using Gln as a routine pharmacologic supplement to the standard nutrition in patients who undergo major operations.

Ampulla of Vater↗
PubMed2006

Comparison of combined hepatocellular and cholangiocarcinoma with hepatocellular carcinoma and intrahepatic cholangiocarcinoma.

PURPOSE: Combined hepatocellular and cholangiocarcinoma (HCC-CC) is a rare primary hepatic neoplasm (PHN) with features of both hepatocellular and biliary differentiation. We compared the outcome of hepatic resection in patients with HCC-CC, those with hepatocellular carcinoma (HCC), and those with cholangiocarcinoma (ICC). METHODS: Between November 1994 and December 2003, 952 patients underwent hepatic resection for a PHN. RESULTS: The incidence of HCC-CC was 3.5%. Hepatitis B surface antigen was positive in 51.2% of these patients and the HCV antibody was positive in 12.2%. Positive hepatitis serology was more common in the HCC group (66.7%). The prevalence of underlying liver cirrhosis was significantly lower in the ICC group (7.8%) than in the HCC (49%) and HCC-CC (41.5%) groups (P < 0.0001). The median overall survival periods after hepatic resection of HCC-CC, HCC, and ICC were 47.3, 71.7, and 21.5 months, respectively (P < 0.0001). The median disease-free survival (DFS) periods after hepatic resection for HCC-CC, HCC, and ICC were 23.4, 68.2, and 15.5 months, respectively (P < 0.0001). CONCLUSION: Patients with transitional type HCC-CC had significantly poorer survival rates than those with HCC, after hepatic resection. Therefore, a more aggressive treatment modality should be explored to improve the survival rate of these patients.

Adolescent↗
PubMed2006

Effect of calcium phosphate glass on bone formation in calvarial defects of Sprague-Dawley rats.

The purpose of this study was to investigate the bone regenerative effect of calcium phosphate glass in vivo. We prepared two different sizes of calcium phosphate glass powder using the system CaO-CaF2-P2O5-MgO-ZnO; the particle size of the powders were 400 microm and 40 microm. 8 mm calvarial critical-sized defects were created in 60 male Sprague-Dawley rats. The animals were divided into 3 groups of 20 animals each. Each defect was filled with a constant weight of 0.5 g calcium phosphate glass powder mixed with saline. As controls, the defect was left empty. The rats were sacrificed 2 or 8 weeks after postsurgery, and the results were evaluated using radiodensitometric and histological studies; they were also examined histomorphometrically. When the bigger powders with 400 microm particle were grafted, the defects were nearly completely filled with new-formed bone in a clean healing condition after 8 week. When smaller powders with 40 microm particle were transplanted, new bone formation was even lower than the control group due to a lot of inflammatory cell infiltration. It was concluded that the prepared calcium phosphate glass enhanced the new bone formation in the calvarial defect of Sprague-Dawley rats and it is expected to be a good potential materials for hard tissue regeneration. The particle size of the calcium phosphate was crucial; 400 microm particles promoted new bone formation, while 40 microm particles inhibited it because of severe inflammation.

Animals↗
PubMed2006

Insulin secretory defect plays a major role in the development of diabetes in patients with distal pancreatectomy.

To investigate the pathogenesis of distal pancreatectomy (d-Px)-induced diabetes in Korean patients, we investigated insulin secretory and sensitivity indexes obtained by oral glucose tolerance testing in 20 patients that had received d-Px (10 with d-Px-induced diabetes and 10 with normal glucose tolerance with d-Px [NGT d-Px]) and in 164 control subjects (77 with type 2 diabetes mellitus and 87 with NGT) that did not receive d-Px. The pancreatectomized subjects had lower fasting serum insulin, homeostasis model assessment of pancreatic beta-cell function (HOMA-beta) levels, and insulinogenic indices than the NGT controls. The HOMA-beta values of nonobese NGT d-Px- and d-Px-induced diabetic subjects were 73.7% and 38.7% of those for nonobese NGT controls, respectively, and HOMA-beta was significantly lower only for d-Px-induced diabetic subjects (P < .01). In obese subjects, the HOMA-beta values of obese d-Px-induced diabetic subjects were significantly lower than those of obese NGT controls (P < .05). The insulin sensitivity was significantly lower in nonobese type 2 diabetes mellitus controls than in nonobese NGT d-Px or in nonobese d-Px-induced diabetic subjects (P < .001 and .05, respectively). These results show that a reduced insulin secretory function is a typical feature of glucose homeostasis in distal pancreatectomized patients and that insulin secretory defect plays a major role in the development of diabetes in these patients. In addition, the study suggests that pancreatic resections of 60% or less and body mass index are not the main causes of diabetes onset after d-Px in this study.

Adult↗
PubMed2006

Maxillary sinus septa: prevalence, height, location, and morphology. A reformatted computed tomography scan analysis.

BACKGROUND: The sinus lift technique may be difficult to perform if an aberrant sinus anatomy is encountered during surgical exposure, such as when a septum is present on the sinus floor. The objective of this study was to determine the prevalence, size, location, and morphology of maxillary sinus septa in the atrophic/edentulous and non-atrophic/dentate maxillary segments. METHODS: The sample population consisted of 100 patients (41 women and 59 men, with a mean age of 50 years, ranging between 19 and 87 years) for whom treatment was being planned for implant-supported restorations. Reformatted computerized tomograms (CT) from 200 sinuses were analyzed using imaging software. RESULTS: The prevalence of one or more septa per sinus was found to be 26.5% (53/200), 31.76% (27/85), and 22.61% (26/115) in the overall study population and the atrophic/edentulous and the non-atrophic/dentate maxillary segments, respectively. In the analysis of the anatomic location of the septa within the sinus, it was revealed that 15 (25.4%) were located in the anterior region, 30 (50.8%) in the middle region, and 14 (23.7%) in the posterior region. The measured heights of the septa varied among the different areas. The mean heights of the septa were 1.63 +/- 2.44, 3.55 +/- 2.58, and 5.46 +/- 3.09 mm in the lateral, middle, and medial areas, respectively. CONCLUSIONS: It can be inferred that there is a wide anatomical variation in the prevalence, size, location, and morphology of maxillary sinus septa, irrespective of the degree of atrophy. Therefore, to prevent the likelihood of complications arising during sinus augmentation procedures, a thorough and extensive understanding of the anatomic structures inherent to the maxillary sinus is indispensable.

Adolescent↗
PubMed2006

The effect of varying the particle size of beta tricalcium phosphate carrier of recombinant human bone morphogenetic protein-4 on bone formation in rat calvarial defects.

BACKGROUND: Beta tricalcium phosphate (beta-TCP) has been developed as one of the carriers of recombinant human bone morphogenetic protein (rhBMP). However, it is not known whether the particle size of beta-TCP is related to its resorption rate and the degree of bone formation. The purpose of this study was to evaluate the effect of using beta-TCP with different particle sizes on the ability of rhBMP-4 to enhance bone formation in the rat calvarial defect model. METHODS: Calvarial, 8-mm-diameter, critical-size defects were created in 100 male Sprague-Dawley rats. Five groups of 20 animals each received either rhBMP-4 (2.5 microg) using beta-TCP with a particle size of 50 to 150 microm, rhBMP-4 (2.5 microg) using beta-TCP with a particle size of 150 to 500 microm, a beta-TCP control with a particle size of 50 to 150 microm, a beta-TCP control with a particle size of 150 to 500 microm, or a sham-surgery control, respectively, and were evaluated by measuring their histologic and histometric parameters following a 2- and 8-week healing interval. RESULTS: There were no significant differences in the defect closure, new bone area, or augmented area between either the two rhBMP-4/beta-TCP groups or between the two beta-TCP control groups at 2 and 8 weeks. CONCLUSIONS: rhBMP-4 combined with either small- or large-particle beta-TCP had a significant effect on the induction of bone formation compared to either a small- or large-particle beta-TCP control or a sham-surgery control. Within the parameters of this study, varying the particle size of beta-TCP did not seem to have a significant effect on bone formation.

Animals↗
PubMed2006

The effects of interproximal distance between roots on the existence of interdental papillae according to the distance from the contact point to the alveolar crest.

BACKGROUND: This study investigated the existence of interdental papillae at certain distances from the contact point to the alveolar crest, depending on the interproximal distance between roots. METHODS: A total of 206 papillae from 80 patients were examined after the inflammation of the papillae had been minimized using non-surgical periodontal therapy. The existence of the interdental papillae was determined using the following categorization: 1) papillae were deemed to be absent if they did not extend all the way up to the contact point between the teeth; and 2) papillae were determined to be present if they filled up to the entire proximal space. The interproximal distance between roots and the distance from the contact point to the alveolar crest were measured when a full-thickness flap was used. The number of papillae present interproximally between roots, according to the distance from the contact point to the alveolar crest, was analyzed using the x2 analysis method, and the linear-by-linear association analysis method was used for trend analysis. RESULTS: The number of papillae that filled the interproximal space decreased with increasing distance from the contact point to the alveolar crest (P <0.05). In addition, the number of papillae that filled the interproximal space decreased with increasing interproximal distance between roots (P <0.05) and became more prominently decreasing with the increasing distance from the contact point to the alveolar crest (especially 4, 5, and 6 mm) (P <0.05). CONCLUSION: The results suggest that the interproximal distance between roots and the distance between the contact point and the alveolar crest have an independent and combined effect on the existence of interproximal papillae.

Adult↗
PubMed2005

Bone formation in calvarial defects of Sprague-Dawley rats by transplantation of calcium phosphate glass.

The purpose of this study was to investigate the bone-regenerative effect of calcium phosphate glass in vivo. We prepared amorphous calcium phosphate glass powder having a mean particle size of 400 microm in the system CaO-CaF2-P2O5-MgO-ZnO. Calvarial critical-sized defects (8 mm) were created in 60 male Sprague-Dawley rats. The animals were divided into an experimental group and control group of 30 animals each. Each defect was filled with a constant weight of 0.5 g calcium phosphate glass powder mixed with saline. As a control, the defect was left empty. The rats were sacrificed 2, 4, or 8 weeks postsurgery, and the results evaluated using radiodensitometric and histological studies; they were also examined histomorphometrically. When the calcium phosphate glass powders with 400-microm particles were grafted, the defects were nearly completely filled with new-formed bone in a clean healing condition after 8 weeks. It was observed that the prepared calcium phosphate glass enhanced new bone formation in the calvarial defect of Sprague-Dawley rats and could be expected to have potential for use as a hard tissue regeneration material.

Animals↗
PubMed2005

The favorable outcome of human islet transplantation in Korea: experiences of 10 autologous transplantations.

BACKGROUND: Cystic neoplasms of the pancreas are an increasingly diagnosed entity, and surgical resection of the pancreas is advocated. Islet autotransplantation is a therapeutic approach used to prevent diabetes in cases of pathologically benign neoplasm after major pancreatectomy. METHODS: A total of 10 patients underwent pancreatectomy with islet autotransplantation. To evaluate islet transplantation efficiency, the authors compared 23 subjects who did not undergo islet transplantation after partial pancreatectomy with 87 subjects with normal glucose tolerance and with 77 diabetic subjects that did not undergo pancreatectomy. RESULTS: Ten female patients with nine cystic neoplasms and one patient with pancreatic injury underwent transplantation. Their mean islet equivalents (IEQ) was 3,159 IEQ/kg. During follow-up, two recipients required insulin or oral agents. At the 12-month follow-up, homeostasis model assessment (HOMA)-beta was 77.36+/-17.68, the insulinogenic index (INSindex) was 0.49+/-0.11, and fasting C-peptide and hemoglobin A1c were 1.28+/-0.18 ng/mL and 5.73+/-0.26%, respectively. Islet replacement was found to increase HOMA-beta by approximately 17% compared with distal pancreatectomy in normal glucose tolerance subjects without islet autotransplantation and by 46% compared with distal pancreatectomy diabetes subjects without islet autotransplantation. Factors different in the two insulin and oral hypoglycemic agent (OHA)-requiring recipients and the eight insulin- and OHA-free recipients were pancreatectomy extent, preoperative glucose metabolism insufficiency, age, and underlying cystic neoplasm disease. CONCLUSIONS: Even partial islet graft function can have a beneficial metabolic effect on the recipient in terms of metabolic parameters such as HOMA-beta and INSindex. This study suggests that islet replacement should be considered for experimental procedures in benign pancreatic conditions.

Administration, Oral↗
PubMed2005

Effects of chitosan nonwoven membrane on periodontal healing of surgically created one-wall intrabony defects in beagle dogs.

The purpose of this study was to investigate the periodontal regenerative effects of a chitosan nonwoven membrane applied to surgically created preclinical one-wall intrabony defects in beagle dogs. One-wall intrabony defects (4 x 4 x 4 mm) were surgically created bilaterally in the mandibular second and fourth premolars of six beagle dogs. The surgical control group received a flap operation only. The resorbable-membrane (RM) group was treated with resorbable membrane. The chitosan-nonwoven-membrane (CNWM) group was treated with chitosan nonwoven membrane. The amount of junctional epithelium migration and the amount of connective tissue adhesion did not show any statistically significant differences among the groups. However, the amount of suprabony cementum regeneration, intrabony cementum regeneration, and alveolar bone regeneration showed significant differences (p < 0.05) between CNWM site group and control group. The results demonstrate the regenerative effects of the chitosan nonwoven membrane in one-wall intrabony defects of beagle dogs. The chitosan nonwoven membrane has the potential to support the cementum and bone regeneration, possibly by providing the conditions needed for guided tissue regeneration in the one-wall intrabony periodontal defects of beagle dogs.

Animals↗
PubMed2005

Ectopic bone formation associated with recombinant human bone morphogenetic proteins-2 using absorbable collagen sponge and beta tricalcium phosphate as carriers.

The ectopic bone formation of recombinant human bone morphogenetic protein-2(rhBMP-2) was evaluated using absorbable collagen sponges (ACS) and beta tricalcium phosphate (beta-TCP) as carriers in a rat subcutaneous assay model. Subcutaneous pockets were created on the back of rats. The pockets were implanted with rhBMP-2/ACS, rhBMP-2/beta-TCP, ACS alone, and beta-TCP alone. The rats were sacrificed at 2 or 8 weeks for histological and immunohistochemical evaluation. At 2 weeks, bone formation was evident in both the rhBMP-2/ACS and rhBMP-2/beta-TCP sites. At 8 weeks, the quantity of the new bone with a more advanced stage of remodeling had increased further in the rhBMP-2/beta-TCP sites. However, the newly formed bone observed at 2 weeks was not found in the rhBMP-2/ACS sites. On immunohistochemical observation, osteopontin staining was observed on both the rhBMP-2/ACS (2 weeks) and rhBMP-2/beta-TCP (2 and 8 weeks) sites. Osteocalcin was not detected in any of the samples. The lack of space-providing capacity of ACS may be one of the major factors responsible for its failure to maintain the newly induced bone. Therefore, a carrier for BMPs should provide space for bone formation and maturation during the more advanced healing stages.

Absorbable Implants↗
PubMed2005

Periodontal healing in one-wall intra-bony defects in dogs following implantation of autogenous bone or a coral-derived biomaterial.

AIM: Autogenous bone grafts and bone biomaterials are being used as part of protocols aiming at reconstruction of periodontal defects. There is a limited biologic information on the effect of such materials on periodontal healing, in particular aberrant healing events that may prevent their general use. The objective of this study was, using histological techniques, to evaluate periodontal healing with focus on root resorption and ankylosis following implantation of autogenous bone and a coral-derived biomaterial into intra-bony defects in dogs. METHODS: One-wall intra-bony periodontal defects were surgically created at the distal aspect of the second and the mesial aspect of the fourth mandibular premolars in either right or left jaw quadrants in four Beagle dogs. Each animal received particulated autogenous bone and the resorbable calcium carbonate biomaterial into discrete one-wall intra-bony defects. The mucoperiosteal flaps were positioned and sutured to their pre-surgery position. The animals were euthanized 8 weeks post-surgery when block sections of the defect sites were collected and prepared for qualitative histological analysis. RESULTS: There were no significant differences in periodontal healing between sites receiving autograft bone and the coral-derived biomaterial. A well-organized periodontal ligament bridging new bone and cementum regeneration was observed extending coronal to a notch prepared to delineate the apical extent of the defect. Osteoid and bone with enclosed osteocytes were formed onto the surface of both autograft and coral particles. Although small resorption pits were evident in most teeth, importantly none of the biomaterials provoked marked root resorption. Ankylosis was not observed. CONCLUSION: Particulated autogenous bone and the coral-derived biomaterial may be implanted into periodontal defects without significant healing aberrations such as root resorption and ankylosis. The histopathological evaluation suggests that the autogenous bone graft has a limited osteogenic potential as demonstrated in this study model.

Animals↗
PubMed2005

The correlation between the bone probing, radiographic and histometric measurements of bone level after regenerative surgery.

BACKGROUND AND OBJECTIVE: The most accurate method of assessing bone level is to elevate the flap and measure the bone level directly. However, this method causes discomfort to the patient and can damage the tissues. Therefore, many studies have been conducted to find an alternative method that can be used to assess the bone level clinically with accuracy and reliability. In the present study, we evaluated the clinical reliability and accuracy of bone probing and radiographic measurements, by comparing the bone levels obtained by both of these measurement techniques with the histometrically confirmed bone levels, after four different kinds of regenerative therapy. METHODS: Twenty-four intrabony defects (4 x 4 mm one-wall intrabony defects) were surgically created bilaterally in the mandibular second and fourth premolars of six beagle dogs. The control group underwent a conventional flap operation. The graft group was treated with calcium phosphate glass only, the guided tissue regeneration group was treated with guided tissue regeneration only, and the graft + guided tissue regeneration group was treated with calcium phosphate glass and guided tissue regeneration. Bone probing and radiographic measurements were performed to assess the bone level 8 weeks after the operation and then the subjects were killed to perform the histometric measurements. The correlation between the bone probing depths and the histometric bone levels, and that between the radiographic bone levels and the histometric bone levels were analyzed by Spearman's rank correlation analysis. The statistical significance with respect to the type of regenerative therapy was analyzed by the Kruskal-Wallis test. RESULTS: The difference between the bone probing depth and the histometric bone level measurements was 0.14, and that between the radiographic bone level and histometric bone level was 0.6. The coefficient of correlation between the bone probing depth and the histometric bone level was 0.90, and that between the radiographic bone level and the histometric bone level was 0.73. The type of regenerative therapy had no significant effect on the difference between the histometric bone level and the other measurements. CONCLUSION: The results of the present study suggest that the bone probing measurement may be a reliable method for the assessment of the actual bone level following any type of periodontal regenerative therapy.

Alveolar Bone Loss↗