Effect of platelet-rich plasma on healing of class III furcation defects treated with autogenous bone grafting and guided tissue regeneration: a histomorphometric study in dogs

The purpose of this study was to evaluate the effects of the platelet-rich plasma (PRP) when used in combination with autogenous bone graft and bioabsorbable membrane (Resolut® ) in the treatment of Class  III furcation defects in dogs. Material and method: Class III furcation defects (5 mm in height and in depth) were surgically created in the mandibular third premolars of five mongrel dogs. After nine weeks, the lesions were treated with scaling and root planning and each defect received one of the following treatments: autogenous bone graft + membrane (group C) or PRP + autogenous bone graft + membrane (group T). After a healing period of 90 days, the animals were sacrificed. Routine histological processing and staining with hematoxilyn and eosin and Masson trichrome were performed and a histomorphometric analysis determined the effect of the treatments on periodontal tissue regereneration. Data were analyzed by Hotelling’s T-squared (p < 0.05). Result: No statistically significant difference between C and T groups was observed by the histomorphometric analysis of the furcation area. Both treatment groups demonstrated similar regenerative results with the furcation defects partially filled and periodontal regeneration limited to the experimental notches of the lesions. (p > 0.05). Conclusion: According to the present results, PRP does not enhance the periodontal regeneration in class III furcation defects treated with autogenous bone graft and bioabsorbable membrane.

Cuspal movement related to different polymerization protocols

Objective: The aim of this study to investigate the effects of different polymerization protocols on the cuspal movement in class II composite restorations. Materials and methods: Human premolar teeth were prepared with class II cavities and then restored with composite and three-step and two-step etch-and-rinse adhesive systems under different curing techniques (n = 10). It was used a lightemittingdiode curing unit and the mode of polymerization were: standard (exposure for 40 seconds at 700 mW/cm2), pulse-delay (initial exposure for 6 seconds at 350 mW/cm2 followed by a resting period of 3 minutes and a final exposure of 37 seconds at 700 mW/cm2) and soft-start curing (exposure 10 seconds at 350 mW/cm2 and 35 seconds at 700 mW/cm2). The cuspal distance (µm) was measured before and after the restorative procedure and the difference was recorded as cuspal movement. The data were submitted to two-way ANOVA and Bonferroni test (p < 0.05). Results: The type of adhesive system did not influenced the cuspal movement for all the curing methods. Standard protocol showed the highest values of cuspal movement and was statistically different from the pulse-delay and soft-start curing modes. Conclusion: Although the cuspal displacement was not completely avoided, alternative methods of photocuring should be considered to minimize the clinical consequences of composites contraction stress.

Chitosan-alginate membranes accelerate wound healing

The purpose of this study was to evaluate the efficacy of chitosan-alginate membrane to accelerate wound healing in experimental cutaneous wounds. Two wounds were performed in Wistar rats by punching (1.5 cm diameter), treated with membranes moistened with saline solution (CAM group) or with saline only (SL group). After 2, 7, 14, and 21 days of surgery, five rats of each group were euthanized and reepithelialization was evaluated. The wounds/scars were harvested for histological, flow cytometry, neutrophil infiltrate, and hydroxyproline analysis. CAM group presented higher inflammatory cells recruitment as compared to SL group on 2nd day. On the 7th day, CAM group showed higher CD11b+ level and lower of neutrophils than SL group. The CAM group presented higher CD4+ cells influx than SL group on 2nd day, but it decreased during the follow up and became lower on 14th and 21st days. Higher fibroplasia was noticed on days 7 and 14 as well as higher collagenesis on 21st in the CAM group in comparison to SL group. CAM group showed faster reepithelialization on 7th day than SL group, although similar in other days. In conclusion, chitosan-alginate membrane modulated the inflammatory phase, stimulated fibroplasia and collagenesis, accelerating wound healing process in rats.

New LLLT protocol to speed up the bone healing process-histometric and immunohistochemical analysis in rat calvarial bone defect

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of oestrogen deficiency and 17 beta-estradiol therapy on bone healing in calvarial critical size defects treated with bovine bone graft

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Raloxifene enhances peri-implant bone healing in osteoporotic rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of alendronate sodium on tooth movement in ovariectomized rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hypertension modifies OPG, RANK, and RANKL expression during the dental socket bone healing process in spontaneously hypertensive rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diabetes reduces mesenchymal stem cells in fracture healing through a TNF alpha-mediated mechanism

Diabetes interferes with bone formation and impairs fracture healing, an important complication in humans and animal models. The aim of this study was to examine the impact of diabetes on mesenchymal stem cells (MSCs) during fracture repair.Fracture of the long bones was induced in a streptozotocin-induced type 1 diabetic mouse model with or without insulin or a specific TNF alpha inhibitor, pegsunercept. MSCs were detected with cluster designation-271 (also known as p75 neurotrophin receptor) or stem cell antigen-1 (Sca-1) antibodies in areas of new endochondral bone formation in the calluses. MSC apoptosis was measured by TUNEL assay and proliferation was measured by Ki67 antibody. In vitro apoptosis and proliferation were examined in C3H10T1/2 and human-bone-marrow-derived MSCs following transfection with FOXO1 small interfering (si)RNA.Diabetes significantly increased TNF alpha levels and reduced MSC numbers in new bone area. MSC numbers were restored to normal levels with insulin or pegsunercept treatment. Inhibition of TNF alpha significantly reduced MSC loss by increasing MSC proliferation and decreasing MSC apoptosis in diabetic animals, but had no effect on MSCs in normoglycaemic animals. In vitro experiments established that TNF alpha alone was sufficient to induce apoptosis and inhibit proliferation of MSCs. Furthermore, silencing forkhead box protein O1 (FOXO1) prevented TNF alpha-induced MSC apoptosis and reduced proliferation by regulating apoptotic and cell cycle genes.Diabetes-enhanced TNF alpha significantly reduced MSC numbers in new bone areas during fracture healing. Mechanistically, diabetes-enhanced TNF alpha reduced MSC proliferation and increased MSC apoptosis. Reducing the activity of TNF alpha in vivo may help to preserve endogenous MSCs and maximise regenerative potential in diabetic patients.

Effect of mesenchymal stem cells on movement and urination of rats with spinal cord injury

Cell therapy has frequently been reported as a possible treatment for spinal trauma in humans and animals; however, without pharmacologically curative action on damage from the primary lesion. In this study, we evaluated the effect of administering human adipose-derived stem cells (hADSC) in rats after spinal cord injury. The hADSC were used between the third and fifth passages and a proportion of cells were transduced for screening in vivo after transplantation. Spinal cord injury was induced with a Fogarty catheter no. 3 inserted into the epidural space with a cuff located at T8 and filled with 80 mu L saline for 5 min. The control group A (n = 12) received culture medium (50 mu L) and group B (n = 12) received hADSC (1.2 x 10(6)) at 7 and 14 days post-injury, in the tail vein. Emptying of the bladder by massage was performed daily for 3 months. Evaluation of functional motor activity was performed daily until 3 months post-injury using the Basso-Beattie-Bresnahan scale. Subsequently, the animals were euthanized and histological analysis of the urinary bladder and spinal cord was performed. Bioluminescence analysis revealed hADSC at the application site and lungs. There was improvement of urinary bladder function in 83.3% animals in group B and 16.66% animals in group A. The analysis of functional motor activity and histology of the spinal cord and urinary bladder demonstrated no significant difference between groups A and B. The results indicate that transplanted hADSC improved urinary function via a telecrine mechanism, namely action at a distance.

Healing at implant sites prepared conventionally or by means of Sonosurgery (R): an experimental study in dogs

ObjectiveTo compare peri-implant tissue healing at implants installed in sites prepared with conventional drills or a sonic device.Material and methodsIn six Beagle dogs, the mandibular premolars and first molars were extracted bilaterally. After 3 months, full-thickness muco-periosteal flaps were elevated and recipient sites were prepared in both sides of the mandible. In the right side (control), the osteotomies were prepared using conventional drills, while, at the left side (test), a sonic device (Sonosurgery((R))) was used. Two implants were installed in each side of the mandible. After 8weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation.ResultsThe time consumed for the osteotomies at the test was more than double compared to the conventional control sites. No statistically significant differences were found for any of the histological variables evaluated for hard and soft tissue dimensions. Although not statistically significant, slightly higher mineralized bone-to-implant contact was found at the test (65.4%) compared to the control (58.1) sites.ConclusionsSimilar healing characteristics in osseointegration and marginal hard tissue remodeling resulted at implants installed into osteotomies prepared with conventional drills or with the sonic instrument (Sonosurgery((R))).