Potential of Bioactive Glass Particles of Different Size Ranges to Affect Bone Formation in Interproximal Periodontal Defects in Dogs

Background: The aim of this study was to compare the potential of bioactive glass particles of different size ranges to affect bone formation in periodontal defects, using the guided tissue regeneration model in dogs. Methods: In six dogs, 2-wall intrabony periodontal defects were surgically created and chronified on the mesial surfaces of mandibular third premolars and first molars bilaterally. After 1 month, each defect was randomly assigned to treatment with bioabsorbable membrane in association with bioactive glass with particle sizes between 300 and 355 mu m (group 1) or between 90 and 710 mu m (group 2), membrane alone (group 3), or negative control (group 4). The dogs were sacrificed 12 weeks after surgeries, and histomorphometric measurements were made of the areas of newly formed bone, new mineralized bone, and bioactive glass particle remnants. Results: With regard to the area of bioactive glass particle remnants, there was a statistically significant difference between groups 1 and 2, favoring group 1. There were greater areas of mineralized bone in groups 1 and 2 compared to groups 3 and 4 (P<0.05). Conclusion: The bioactive glass particles of small size range underwent faster resorption and substitution by new bone than the larger particles, and the use of bioactive glass particles favored the formation of mineralized bone. J Periodontol 2009;80:808-815.

Effect of soft laser in bone repair after expansion of the midpalatal suture in dogs

Introduction: The purpose of this research was to study the influence of soft laser treatment on the process of bone repair after expansion of the midpalatal suture. Methods: The sample for this case-control experimental study was 11 dogs. They were randomly divided into 2 groups, both of which underwent rapid maxillary expansion with a hyrax appliance. The animals in group 1 were also treated with laser therapy. They were killed, and histologic specimens of the palatal suture were prepared. The Student t test was applied for independent data, and the Mann-Whitney test was used for nonparametric data. Results: A significant difference was observed in the quality of the palatal sutures between the animals in groups 1 and 2. The connective tissues of the sutures in the group 1 animals were similar to the original configurations, with more advanced osteogenesis and fibrogenesis, compared with those of group 2. Conclusions: Soft laser appears to influence the behavior of the repair process, contributing to suture reorganization and palatal bone osteogenesis during and after expansion. (Am J Orthod Dentofacial Orthop 2012; 142: 615-24)

Short implants (6 mm) installed immediately into extraction sockets: An experimental study in dogs

Aim: To evaluate the effect of implant length (6 mm vs. 11 mm) on osseointegration (bone-toimplant contact) of implants installed into sockets immediately after tooth extraction. Material and methods: In six Labrador dogs, the pulp tissue of the mesial roots of P-3(3) was removed and the root canals were filled. Flaps were elevated bilaterally, the premolars hemisectioned and the distal roots removed. Recipient sites were prepared in the distal alveolus and a 6 mm or an 11 mm long implant was installed at the test and control sites, respectively. Non-submerged healing was allowed. After 4 months of healing, block sections of the implant sites were obtained for histological processing and peri-implant tissue assessment. Results: No statistically significant differences were found between test and control sites both for hard and soft tissue parameters. The bone-to-implant contact evaluated at the apical region of the implants was similar as well. Although not statistically significant, the location of the top of the bony crest at the buccal aspect was more apical in relation to the implant shoulder at the test compared with the control sites (2.0 +/- 1.4 and 1.2 +/- 1.1 mm, respectively). Conclusions: Shorter implants (6 mm) present with equal osseointegration than do longer implants (11 mm).

Effect of Si addition on Ca- and P-impregnated implant surfaces with nanometer-scale roughness: an experimental study in dogs

Objectives: To investigate the effect of Si addition on a nanometer-scale roughness Ca and P implant surfaces in a canine tibia model by biomechanical and histomorphometric evaluations. Material and methods: The implant surfaces comprised a resorbable media CaP microblasted (control) and a CaP resorbable media + silica-boost microblasted (experimental) surfaces. Surfaces were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and optical interferometry (IFM) down to the nanometric level. The animal model involved the bilateral placement of control (n = 24) and experimental surface (n = 24) implants along the proximal tibiae of six dogs, remaining in vivo for 2 or 4 weeks. After euthanization, half of the specimens were torquedto- interface failure, and the other half was subjected to histomorphologic and bone-to-implant contact (BIC) evaluation. Torque and BIC statistical evaluation was performed by the Friedman test at 95% level of significance, and comparisons between groups was performed by the Dunn test. Results: IFM and SEM observations depicted comparable roughness parameters for both implant surfaces on the micrometer and nanometer scales. XPS analysis revealed similar chemical composition, except for the addition of Si on the experimental group. Torque-to-interface failure and BIC mean values showed no significant differences (P = 0.25 and 0.51, respectively) at both 2- and 4-week evaluation points for experimental and control groups. Early bone healing histomorphologic events were similar between groups. Conclusions: The experimental surface resulted in not significantly different biomechanical fixation and BIC relative to control. Both surfaces were biocompatible and osseoconductive.

Early peri-implant endosseous healing of two implant surfaces placed in surgically created circumferential defects. A histomorphometric and fluorescence study in dogs

Objective Several implant surfaces are being developed, some in the nanoscale level. In this study, two different surfaces had their early healing properties compared in context of circumferential defects of various widths. Material and methods Six dogs had the mandibular premolars extracted. After 8weeks, four implants were placed equicrestally in each side. One acted as control, while the others were inserted into sites with circumferential defects of 1.0, 1.5 and 2.0mm wide and 5mm deep. A nano-modified surface was used on one side and a micro-rough on the other. Bone markers were administered on the third day after implant placement and then after 1, 2, 4weeks to investigate the bone formation dynamic through fluorescence analysis. Ground sections were prepared from 8-week healing biopsies and histomorphometry was performed. Results The fluorescence evaluation of the early healing showed numerically better results for the nano-modified group; however this trend was not followed by the histomorphometric evaluation. A non-significant numerical superiority of the micro-rough group was observed in terms of vertical bone apposition, defect bone fill, bone-to-implant contact and bone density. In the intra-group analysis, the wider defects showed the worse results while the control sites showed the best results for the different parameters, but without statistical relevance. Conclusion Both surfaces may lead to complete fill of circumferential defects, but the gap width has to be considered as a challenge. The nano-scale modification was beneficial in the early stages of bone healing, but the micro-rough surface showed numerical better outcomes at the 8-week final period.

Evaluation of a nanometer roughness scale resorbable media-processed surface: a study in dogs

Objectives: This study compared the biomechanical fixation and bone-to-implant contact (BIC) of implants with different surfaces treatment (experimental resorbable blasting media-processed nanometer roughness scale surface, and control dual acid-etched) in a dog model. Material and methods: Surface characterization was made in six implants by means of scanning electron microscopic imaging, atomic force microscopy to evaluate roughness parameters, and X-ray photoelectron spectroscopy (XPS) for chemical assessment. The animal model comprised the bilateral placement of control (n = 24) and experimental surface (n = 24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Half of the specimens were biomechanically tested (torque), and the other half was subjected to histomorphologic/ morphometric evaluation. BIC and resistance to failure measures were each evaluated as a function of time and surface treatment in a mixed model ANOVA. Results: Surface texturing was significantly higher for the experimental compared with the control surface. The survey XPS spectra detected O, C, Al, and Ti at the control group, and Ca (similar to 0.2-0.9%) and P (similar to 1.7-4.1%) besides O, C, Al, and Ti at experimental surfaces. While no statistical difference in BIC was found between experimental and control surfaces or between 2 and 4 weeks in vivo, both longer time and use of experimental surface significantly increased resistance to failure. Conclusions: The experimental surface resulted in enhanced biomechanical fixation but comparable BIC relative to control, suggesting higher bone mechanical properties around the experimental implants.

Thrombocytopenia and platelet activity in dogs experimentally infected with Rangelia vitalii

The aim of this study was to evaluate the platelet count, coagulation time and platelet activity in dogs experimentally infected with Rangelia vitalii during the acute phase of the disease. For this study, 12 young dogs (females) were used, separated in two groups. Group A (uninfected control) was composed by healthy dogs (n=5), and group B consisted of R. vitalii-infected animals (n=7). After being inoculated with R. vitalii-infected blood, animals were monitored by blood smear examinations, which showed intra-erythrocytic forms of the parasite five days post-inoculation (PI). Blood samples were collected on days 0, 10, 20 and 30 PI. The material collected was placed in tubes containing EDTA for quantification of platelets, citrate anticoagulant platelet aggregation, and measuring the clotting time. Right after blood collection on days 10 and 20 PI, dogs were anesthetized for collecting bone marrow samples. A significant reduction (P<0.01) of the number of platelets was observed in R. vitalii-infected blood, when compared with uninfected dogs on days 10 and 20 PI. Additionally, macro-platelets were observed only in infected dogs. Prothrombin time and activated partial thromboplastin time did not differ between infected and uninfected dogs. The megakaryocyte count increased (P<0.01) significantly in infected dogs when compared with uninfected ones on days 10 and 20 PI. Platelet aggregation decreased (P<0.01) significantly in infected dogs in comparison to the control on days 10 and 20 PI. Therefore, rangeliosis in dogs causes a severe thrombocytopenia during the acute phase of infection. This platelets reduction probably occurred due to splenic sequestration and/or immune-mediated thrombocytopenia. (C) 2011 Elsevier B.V. All rights reserved.

Periapical Tissue Response After Use of Intermediate Restorative Material, Gutta-Percha, Reinforced Zinc Oxide Cement, and Mineral Trioxide Aggregate as Retrograde Root-End Filling Materials: A Histologic Study in Dogs

Purpose: To investigate the periapical tissue response of 4 different retrograde root-filling materials, ie, intermediate restorative material, thermoplasticized gutta-percha, reinforced zinc oxide cement (Super-EBA), and mineral trioxide aggregate (MTA), in conjunction with an ultrasonic root-end preparation technique in an animal model. Materials and Methods: Vital roots of the third and fourth right mandibular premolars in 6 healthy mongrel dogs were apicectomized and sealed with 1 of the materials using a standardized surgical procedure. After 120 days, the animals were sacrificed and the specimens were analyzed radiologically, histologically, and scanning electron microscopically. The Fisher exact test was performed on the 2 outcome values. Results: Twenty-three sections were analyzed histologically. Evaluation showed better re-establishment of the periapical tissues and generally lower inflammatory infiltration in the sections from teeth treated with the intermediate restorative material and the MTA. New root cement on the resected dentin surfaces was seen on all sections regardless of the used material. New hard tissue formation, directly on the surface of the material, was seen only in the MTA sections. There was no statistical difference in outcome among the tested materials. Conclusions: The results from this dog model favor the intermediate restorative material and MTA as retrograde fillings when evaluating the bone defect regeneration. MTA has the most favorable periapical tissue response when comparing the biocompatibility of the materials tested. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:2041-2047, 2012

Acute exercise adjustments of cardiovascular autonomic control in diabetic rats

Introduction: We evaluated the role of cardiovascular autonomic changes in hemodynamics at rest and in response to exercise in streptozotocin-induced diabetic rats. Methods: Male Wistar rats were divided into nondiabetic (ND, n = 8) and diabetic (D, n = 8) groups. Arterial pressure signals were recorded in the basal state and after atropine or propranolol injections at rest, during exercise and during recovery. Results: At rest, vagal tonus was reduced in D (37 +/- 3 bpm) in comparison with the ND group (61 +/- 9 bpm). Heart rate during exercise was lower in D in relation to ND rats associated with reduced vagal withdrawal in the D group. The D rats had an increase in vagal tonus in the recovery period (49 +/- 6 bpm). Conclusions: Exercise-induced hemodynamic adjustment impairment in diabetic rats was associated with reduced cardiac vagal control. The vagal dysfunction was attenuated after aerobic exercise, reinforcing the positive role of this approach in the management of cardiovascular risk in diabetics. Muscle Nerve 46: 96101, 2012

Glucose Control in Acute Myocardial Infarction: A Pilot Randomized Study Controlled by Continuous Glucose Monitoring System Comparing the Use of Insulin Glargine with Standard of Care

Background: This pilot study aimed to verify if glycemic control can be achieved in type 2 diabetes patients after acute myocardial infarction (AMI), using insulin glargine (iGlar) associated with regular insulin (iReg), compared with the standard intensive care unit protocol, which uses continuous insulin intravenous delivery followed by NPH insulin and iReg (St. Care). Patients and Methods: Patients (n = 20) within 24 h of AMI were randomized to iGlar or St. Care. Therapy was guided exclusively by capillary blood glucose (CBG), but glucometric parameters were also analyzed by blinded continuous glucose monitoring system (CGMS). Results: Mean glycemia was 141 +/- 39 mg/dL for St. Care and 132 +/- 42 mg/dL for iGlar by CBG or 138 +/- 35 mg/dL for St. Care and 129 +/- 34 mg/dL for iGlar by CGMS. Percentage of time in range (80-180 mg/dL) by CGMS was 73 +/- 18% for iGlar and 77 +/- 11% for St. Care. No severe hypoglycemia (<= 40 mg/dL) was detected by CBG, but CGMS indicated 11 (St. Care) and seven (iGlar) excursions in four subjects from each group, mostly in sulfonylurea users (six of eight patients). Conclusions: This pilot study suggests that equivalent glycemic control without increase in severe hyperglycemia may be achieved using iGlar with background iReg. Data outputs were controlled by both CBG and CGMS measurements in a real-life setting to ensure reliability. Based on CGMS measurements, there were significant numbers of glycemic excursions outside of the target range. However, this was not detected by CBG. In addition, the data indicate that previous use of sulfonylurea may be a potential major risk factor for severe hypoglycemia irrespective of the type of insulin treatment.

Effectiveness of an exercise program on postural control in frail older adults

Background: Exercise programs have proved to be helpful for frail older adults. This study aimed to investigate the effects of an exercise program with a focus on postural control exercises in frail older adults. Method: Twenty-six older adults (76.7 +/- 4.9 years) deemed clinically stable, chosen from the Falls Unit, University Hospital Mutua Terrassa, Barcelona, Spain, participated in this single-group study. Volunteers' postural control was evaluated using the Timed Up and Go test (TUG) and the Guralnik test battery, and their static and dynamic posturography were evaluated using the Synapsys Posturography System (R). These evaluations were performed before and after the intervention program, which included an educational session and two weekly 1-hour sessions over an 8-week period of stretching exercises, proprioception, balance, and motor coordination. Data were analyzed using the Student's t-test or the Wilcoxon test, with a significance level of 5%. Results: The TUG and Guralnik tests did not show significant differences. Concerning static posturography, there was improvement in the base of support (P = 0.006), anteroposterior displacement with eyes open (P = 0.02) and closed (P = 0.03), and the total amplitude of the center of pressure with eyes closed (P = 0.02). Regarding dynamic posturography, a decrease of the oscillation speed in the anteroposterior direction (P = 0.01) was observed in individuals with their eyes open. Conclusion: The program used in this study was safe and was able to promote some improvement in postural control, especially in the anteroposterior direction and in the base of support. However, it is noteworthy that further improvements could be obtained from a program of longer duration and greater frequency.

Occurrence and antimicrobial susceptibility of Porphyromonas spp. and Fusobacterium spp. in dogs with and without periodontitis

The occurrence of Porphyromonas gulae, Porphyromonas macacae, Fusobacterium nucleatum and Fusobacterium canifelinum in subgingival plaque from dogs with and without periodontitis as well as their antimicrobial susceptibility were evaluated. From 50 dogs with periodontitis were identified 38 P. gulae, 8 P. macacae, 26 F. nucleatum and 15 F. canifelinum, and from 50 dogs without periodontitis were identified 15 P. gulae, 12 F. nucleatum and 11 F. canifelinum. All strains were susceptible to most of the antibiotics tested, however, different resistance rates to clarithromycin, erythromycin and metronidazole among strains were observed. The role of P. gulae, P. macacae, F. nucleatum and F. canifelinum in periodontal disease of household pets needs to be defined to a better prevention and treatment of the canine periodontitis. (c) 2012 Elsevier Ltd. All rights reserved.

Buccal Bone Plate Remodeling After Immediate Implant Placement With and Without Synthetic Bone Grafting and Flapless Surgery: Radiographic Study in Dogs

Recent studies in animals have shown pronounced resorption of the buccal bone plate after immediate implantation. The use of flapless surgical procedures prior to the installation of immediate implants, as well as the use of synthetic bone graft in the gaps represent viable alternatives to minimize buccal bone resorption and to favor osseointegration. The aim of this study was to evaluate the healing of the buccal bone plate following immediate implantation using the flapless approach, and to compare this process with sites in which a synthetic bone graft was or was not inserted into the gap between the implant and the buccal bone plate. Lower bicuspids from 8 dogs were bilaterally extracted without the use of flaps, and 4 implants were installed in the alveoli in each side of the mandible and were positioned 2.0 mm from the buccal bone plate (gap). Four groups were devised: 2.0-mm subcrestal implants (3.3 x 8 mm) using bone grafts (SCTG), 2.0-mm subcrestal implants without bone grafts (SCCG), equicrestal implants (3.3 x 10 mm) with bone grafts (EGG), and equicrestal implants without bone grafts (ECCG). One week following the surgical procedures, metallic prostheses were installed, and within 12 weeks the dogs were sacrificed. The blocks containing the individual implants were turned sideways, and radiographic imaging was obtained to analyze the remodeling of the buccal bone plate. In the analysis of the resulting distance between the implant shoulder and the bone crest, statistically significant differences were found in the SCTG when compared to the ECTG (P = .02) and ECCG (P = .03). For mean value comparison of the resulting linear distance between the implant surface and the buccal plate, no statistically significant difference was found among all groups (P > .05). The same result was observed in the parameter for presence or absence of tissue formation between the implant surface and buccal plate. Equicrestally placed implants, in this methodology, presented little or no loss of the buccal bone. The subcrestally positioned implants presented loss of buccal bone, even though synthetic bone graft was used. The buccal bone, however, was always coronal to the implant shoulder.

Dyslipidemia: a prospective controlled randomized trial of intensive glycemic control in sepsis

Metabolic disturbances are quite common in critically ill patients. Glycemic control appears to be an important adjuvant therapy in such patients. In addition, disorders of lipid metabolism are associated with worse prognoses. The purpose of this study was to investigate the effects that two different glycemic control protocols have on lipid profile and metabolism. We evaluated 63 patients hospitalized for severe sepsis or septic shock, over the first 72 h of intensive care. Patients were randomly allocated to receive conservative glycemic control (target range 140-180 mg/dl) or intensive glycemic control (target range 80-110 mg/dl). Serum levels of low-density lipoprotein, high-density lipoprotein, triglycerides, total cholesterol, free fatty acids, and oxidized low-density lipoprotein were determined. In both groups, serum levels of low-density lipoprotein, high-density lipoprotein, and total cholesterol were below normal, whereas those of free fatty acids, triglycerides, and oxidized low-density lipoprotein were above normal. At 4 h after admission, free fatty acid levels were higher in the conservative group than in the intensive group, progressively decreasing in both groups until hour 48 and continuing to decrease until hour 72 only in the intensive group. Oxidized low-density lipoprotein levels were elevated in both groups throughout the study period. Free fatty acids respond to intensive glycemic control and, because of their high toxicity, can be a therapeutic target in patients with sepsis.

The functional role of ascending nociceptive control in defensive behavior

Ascending nociceptive control is a novel spino-striato-rostral ventral medulla pain modulation pathway that mediates heterosegmental pain-induced analgesia, i.e., noxious stimulus-induced antinociception. In this study, we used the dorsal immobility response in rats as a model of the defensive responses. We demonstrated that the activation of ascending nociceptive control by peripheral noxious stimulation and spinal AMPA and mGluR1 receptor blockade significantly potentiated the duration of the dorsal immobility response in rats via an opioid-dependent mechanism in the nucleus accumbens. These results demonstrated the functional role of ascending nociceptive control in the modulation of defensive responses and spinal glutamatergic receptors in the dorsal immobility response. The immobility response is an antipredator behavior that reflects the underlying state of fear, and ascending nociceptive control may modulate fear. (c) 2012 Elsevier B.V. All rights reserved.