Synergistic effect of hyperbaric oxygen therapy with PTH [1-34] on calvarial bone graft in irradiated rat.

OBJECTIVE: To determine the synergistic effect of parathyroid hormone (PTH) [1-34] in combination with hyperbaric oxygen (HBO) on bone graft in a rat calvarial bone defect model under impaired osteogenic conditions. MATERIALS AND METHODS: Twenty-four rats were divided into three groups. Localized radiation with a single 12 Gy dose was administered to the calvaria. Four weeks after radiation, calvarial circular defects were created in the parietal bones. All defects were filled with biphasic calcium phosphate. After the bone graft, PTH [1-34] was injected subcutaneously, and HBO was administered. At 6 weeks after the bone graft, the rats were sacrificed, and specimens were harvested. RESULTS: Histomorphometric evaluation showed that the percentage of new bone area was higher in the PTH and PTH/HBO groups than in the control group. The percent residual material area was decreased in the PTH/HBO group compared with the control group. The percentage blood vessel number was highest in the PTH group. Micro-CT evaluation showed that the new bone volume was highest in the PTH/HBO group. The residual material volume was lowest in the PTH/HBO group. CONCLUSION: Within the limitations of this study, our data indicate that PTH combined with HBO may reverse radiation-induced impairment of bone healing.

Primary stability comparison using piezoelectric or conventional implant site preparation systems in cancellous bone: a pilot study.

PURPOSE: This study compares implant primary stability achieved in cancellous bone after placement in piezoelectric prepared sites versus conventionally drilled sites. MATERIALS AND METHODS: Four bovine ribs were randomly assigned and placed in a water bath at 36.5 °C. Five sites per rib (total n = 20 sites) were prepared using piezoelectric system (test) or conventional drills (control) with twenty 10 × 3.6-mm Implantium implants placed. Using Osstell Mentor quantitative analysis, 5 resonance frequency analysis [implant stability quotient {ISQ}] values per implant were recorded at 5 locations for a total of 100 measurements. RESULTS: Independent t test analysis indicated significant difference in primary stabilities between groups: t (17) = 2.637, P = 0.17, with equal variance assumption satisfied (P = 0.196). Examination of means indicated a higher mean ISQ for piezoelectric than for conventional: 58.9 (+8.55) versus 49.2 (+7.33), respectively. Analysis of variance indicated a significant difference in mean ISQ value by rib. Tukey test indicated significantly higher ISQ values for rib A (test) than ribs B, C (control), and D (test). CONCLUSION: Implant site preparation using the piezoelectric system gives higher implant primary stability in cancellous bone. However, variations in quality across bones may have affected the results.

Comparison of fracture resistance of pressable metal ceramic custom implant abutment with a commercially fabricated CAD/CAM zirconia implant abutment.

STATEMENT OF PROBLEM: The predictable nature of the hot pressing ceramic technique has several applications, but no study was identified that evaluated its application to the fabrication of custom implant abutments. PURPOSE: The purpose of this study was to compare the fracture resistance of an experimentally designed pressable metal ceramic custom implant abutment (PR) with that of a duplicate zirconia abutment (ZR). MATERIALS AND METHODS: Two groups of narrow platform (NP) (Nobel Replace) implant abutment specimens were fabricated (n=10). The experimental abutment (PR) had a metal substructure cast with ceramic alloy (Lodestar) and veneered with leucite pressable glass ceramic (InLine PoM). Each PR abutment was individually scanned and 10 duplicate CAD/CAM ZR abutments were fabricated for the control group. Ceramic crowns (n=20) with the average dimensions of a human lateral incisor were pressed with lithium disilicate glass ceramic (IPS e.max Press) and bonded on the abutments with a resin luting agent (Multilink Automix). The specimens were subjected to thermocycling, cyclic loading, and finally static loading to failure with a computer-controlled Universal Testing Machine. An independent t test (1 sided) determined whether the mean values of the fracture load differed significantly (α=.05) between the 2 groups. RESULTS: No specimen failed during cyclic loading. Upon static loading, the mean (SD) load to failure was significantly higher for the PR group (525.89 [143.547] N) than for the ZR group (413.70 [35.515] N) for internal connection narrow platform bone-level implants (P=.025). Failure was initiated at the screw and internal connection level for both groups. CONCLUSIONS: It is possible to fabricate PR abutments that are stronger than ZR abutments for Nobel Biocare internal connection NP bone-level implants. The screw and the internal connection are the weak links for both groups.

Piezoelectric vs. conventional implant site preparation: ex vivo implant primary stability.

OBJECTIVES: This study aims to determine differences in primary stability between implants placed in cortical bone following Piezoelectric or conventional site preparation, as assessed by resonance frequency analysis (RFA) and reverse torque testing (RTT). MATERIAL AND METHODS: Four fresh bovine ribs were acquired and surgical guides fabricated with five sites per rib (n = 20), for proper site preparation. Implant sites were prepared via conventional drilling technique as per manufacturer's instruction (Implantium) or via Piezoelectric (Mectron) implant site preparation using the Implant Prep kit. Twenty 10 mm long, 3.6 mm diameter Implantium implants were placed with 35 Ncm torque; 10 implants per preparation method. RFA was assessed via the Osstell Mentor. Five values were taken per implant. All implants where subjected to a reverse torque in increasing increments of 5 until 50 Ncm force was reached. RESULTS: The five RFA values per site were averaged and plotted by placement technique. A paired t-test statistical analysis was run. The average RFA values showed no statistical significance between the 10 test (RFA = 69.04 ± 5.11) and 10 control (RFA = 70.94 ± 6.41) sites (P > 0.05). All implants in both groups withstood RTT up to 50 Ncm force without movement and thus showed no statistical differences. CONCLUSION: Results of this ex vivo study imply that the Piezoelectric implant site preparation affords similar primary implant stability in comparison to conventional rotary instrumentation in cortical bone.

Comparison of fracture resistance of pressable metal ceramic custom implant abutments with CAD/CAM commercially fabricated zirconia implant abutments.

STATEMENT OF PROBLEM: The adequacy of the strength of dental zirconia abutments under heavy occlusal load conditions is questionable, with degradation of the mechanical properties of zirconia having been reported. Therefore, some alternatives must be considered. PURPOSE: The purpose of this study was to determine the efficacy of fabricating pressable metal ceramic custom implant (Pr) abutments, and to evaluate the fracture resistance of these abutments. MATERIAL AND METHODS: Two groups of implant abutment specimens were fabricated (n=10). The experimental group consisted of Pr abutments, and the control group consisted of CAD/CAM-designed zirconia-based ceramic (Zr) abutments. For the experimental group, custom metal abutments were cast using a compatible metal alloy (Lodestar); this was followed by injection molding with lithium disilicate pressable ceramic (IPS e.max Press) around the metal column of the custom implant abutment. For the control group, 10 specimens were fabricated from CAD/CAM-designed zirconia abutments (Procera Zirconia). Following scanning, all-ceramic crowns with the average dimensions of a human central incisor were fabricated for the experimental and control abutments (n=20) using lithium disilicate pressable ceramic (IPS e.max Press). Each crown was cemented to the implant abutments with a resin luting agent (Variolink II). The crown-abutment test specimens were fixed to titanium implant analogs and placed in a test stand at 30 degrees from the vertical axis of the specimens in a computer-controlled universal testing device. The independent t test was used to detect if the mean values of the fracture load differed significantly (alpha=.05) between the 2 groups. RESULTS: The mean (SD) fracture load was significantly higher in the Pr group (901.67 (102.05) N) than in the Zr group (480.01 (174.46) N, P<.005). CONCLUSIONS: This study found that Pr abutments are stronger than Zr abutments.

Periodontal biotype modification using a volume-stable collagen matrix and autogenous subepithelial connective tissue graft for the treatment of gingival recession: a case series.

PURPOSE: The purpose of this study was to propose a technique for periodontal biotype modification through thickening of the entire facial aspect using a volume-stable collagen matrix and autogenous subepithelial connective tissue graft (CTG) for the treatment of gingival recession. METHODS: Four systemically healthy patients showing Miller class I or class II gingival recession in the mandibular incisor area were included in this study. Full-mouth scaling and root planing procedures were performed at least 4 weeks prior to periodontal plastic surgery. A split-thickness flap with a horizontal intrasulcular incision and 2 vertical incisions was used in cases 1-3, and the modified tunnel technique was used in case 4 for coronal advancement of the mucogingival complex. After the exposed root surfaces were debrided thoroughly, double-layered volume-stable collagen matrix was placed on the apical part of the recession and a subepithelial CTG harvested from the palatal area was placed on the coronal part. The amount of root coverage at 3 months postoperatively was evaluated in cases 1-3, and facio-lingual volumetric changes were analyzed in cases 1 and 2. RESULTS: Healing was uneventful in all 4 cases and complete root coverage was shown in cases 1-3. In case 4, reduction of gingival recession was observed at 3 months after surgery. In cases 1 and 2, a comparison of stereolithographic files from the preoperative and postoperative time points demonstrated that the entire facio-lingual volume had increased. CONCLUSIONS: The surgical technique suggested herein, using a volume-stable collagen matrix and autogenous subepithelial CTG, may be an effective method for periodontal biotype modification through thickening of the entire facial aspect for the treatment of gingival recession.

Ridge preservation using basic fibroblast growth factor-2 and collagenated biphasic calcium phosphate in beagle dogs.

PURPOSE: The aim of this study was to evaluate volumetric and histologic changes in edentulous alveolar ridge areas after ridge preservation using basic fibroblast growth factor-2 (bFGF-2) in combination with collagenated biphasic calcium phosphate (BCP). METHODS: The experiments were performed in 6 adult male beagle dogs. The following 3 groups were created: 1) ridge preservation with bFGF-2 and collagenated BCP (experimental group), 2) ridge preservation with collagenated BCP (positive control group), and 3) a negative control group in which no ridge preservation procedure was performed. Volumetric change analysis was performed using an optical scanner and casts. Histological observations were made using light microscopy. RESULTS: After the initial swelling subsided, the magnitude of the volumetric change in the experimental group and positive control group was smaller than in the negative control group. In the experimental group, a distinct trend was observed for the resorption of residual bone and collagen fibers at 4 weeks and for more mature bone and faster healing at 12 weeks. CONCLUSIONS: Based on the findings of the present study, bFGF-2 may be considered for use as a therapeutic molecule in ridge preservation procedures.

Should anticoagulants be administered for portal vein thrombosis associated with acute pancreatitis?

Venous complications in patients with acute pancreatitis typically occur as a form of splenic, portal, or superior mesenteric vein thrombosis and have been detected more frequently in recent reports. Although a well-organized protocol for the treatment of venous thrombosis has not been established, anticoagulation therapy is commonly recommended. A 73-year-old man was diagnosed with acute progressive portal vein thrombosis associated with acute pancreatitis. After one month of anticoagulation therapy, the patient developed severe hematemesis. With endoscopy and an abdominal computed tomography scan, hemorrhages in the pancreatic pseudocyst, which was ruptured into the duodenal bulb, were confirmed. After conservative treatment, the patient was stabilized. While the rupture of a pseudocyst into the surrounding viscera is a well-known phenomenon, spontaneous rupture into the duodenum is rare. Moreover, no reports of upper gastrointestinal bleeding caused by pseudocyst rupture in patients under anticoagulation therapy for venous thrombosis associated with acute pancreatitis have been published. Herein, we report a unique case of massive upper gastrointestinal bleeding due to pancreatic pseudocyst rupture into the duodenum, which developed during anticoagulation therapy for portal vein thrombosis associated with acute pancreatitis.

Treatment Response and Tolerability of Pegylated Interferon-α Plus Ribavirin Combination Therapy in elderly Patients (≥ 65 years) With Chronic Hepatitis C in Korea.

BACKGROUND: The prevalence of hepatitis C virus (HCV) infections in elderly patients has been increasing in a number of countries. A few reports concerning pegylated interferon-α (PEG-IFN-α)-based combination treatment in elderly chronic hepatitis C (CHC) patients have been published, with slightly different treatment outcomes. OBJECTIVES: We investigated the treatment response and safety of PEG-IFN-α plus ribavirin combination therapy in elderly patients with CHC. PATIENTS AND METHODS: Among a total of 181 treatment-naïve CHC patients (60 patients with genotype 1, 121 patients with genotype 2 or 3), 38 were aged ≥ 65 years (defined as the elderly group) and 143 were aged < 65 years (defined as the non-elderly group). RESULTS: The overall sustained virologic response (SVR) was lower in the elderly group than in the non-elderly group, but it was not significantly different (65.8 % vs. 76.2 %, P = 0.15). In a subgroup analysis, among patients with genotype 1, the elderly group had a significantly lower SVR rate than the non-elderly group (30.8 % vs. 66.0 %, P = 0.03). However, the SVR rate in patients with HCV genotype 2 or 3 was comparable between the two groups (84.0 % vs. 81.3 %, P = 0.85). HCV genotype was significantly associated with SVR in the elderly patients (genotype 1 vs. 2 or 3, odds ratio: 0.18, 95% confidence interval: 0.000-0.869, P = 0.03). The incidence of premature discontinuation of treatment (21.1 % vs. 9.1 %, P = 0.05) and dose modification (52.6 % vs. 31.5 %; P = 0.02) due mainly to adverse events or laboratory abnormalities, were higher in the elderly group than in the non-elderly group. CONCLUSIONS: PEG-IFN-α plus ribavirin combination therapy might be considered for elderly CHC patients, especially for genotype 2 or 3, with vigilant monitoring of adverse events.