Comparative evaluation of the shaping ability of two different nickel-titanium rotary files in curved root canals of extracted human molar teeth.

AIM: The aim of the present study was to compare the shaping ability of two different nickel-titanium rotary files in the curved root canals of extracted human molar teeth. METHODS: Thirty root canals of 17 extracted human molars teeth were randomly assigned to two experimental groups (n = 15): ProTaper Next and ProTaper Universal (PTU), on the basis of the rotary files system used. The final size of all apical foramina was 0.25 mm in diameter. Standardized digital radiographs were taken before and after instrumentation in both clinical and proximal views, with a size 10 K-file inserted into the canal for the determination of the angle of curvature and apical transportation. Preparation time and fractured or deformed instruments were also recorded. The unpaired Student's t-test was used to compare results. RESULTS: There was no significant difference between the two instruments with respect to canal straightening and apical transportation before and after instrumentation (P > 0.05). The use of both instruments resulted in a significant reduction in the angle of curvature after instrumentation (P < 0.05). Instrumentation time was significantly greater for PTU (P < 0.05). CONCLUSIONS: The ProTaper Universal and ProTaper Next systems performed similarly with regard to the straightening of curved root canals and apical transportation. ProTaper Next was significantly faster than ProTaper Universal.

Effect of an Activated Platelet Concentrate on Differentiated Cells Involved in Tissue Healing.

Tissue healing is a complex process involving several players such as cells and growth factors released from platelets upon activation. Today, platelet concentrates (PCs) are used in many different medical fields including oral, orthopaedic, and reconstructive surgery since they allow growth factors delivery to the injured site, aiming at enhancing tissue regeneration. The purpose of this in vitro study was to evaluate the effect of the acellular plasma of an activated platelet concentrate obtained using a manual protocol, on the proliferation, and biological activity of differentiated cells involved in tissue healing. Human osteoblasts and dermal fibroblasts were grown in serum-free medium supplemented with PC derived from several donors. Human osteoblast and human dermal fibroblast proliferation was assessed by MTT test after 7 days and cells were count up to 12-day incubation. Human osteoblast osteo-differentiation was tested after 7 and 14-day incubation by alkaline phosphatase assay. The addition of PC to the culture medium caused an increased proliferation with respect to cells grown in standard condition. The results of the present study suggest that PC supports the proliferation of terminally differentiated cells involved in wound healing and tissue regeneration, confirming its beneficial clinical application in regenerative therapies.

Does Freeze-Thawing Influence the Effects of Platelet Concentrates? An In Vitro Study on Human Adipose-Derived Stem Cells.

Human adipose-derived stem cells (hASCs) have been proposed as a possible therapy for tissue regeneration in aesthetic, plastic, and reconstructive surgery. Today, platelet concentrates are used in a wide range of disciplines, but their storage has become a controversial aspect. The purpose of this in vitro study was to evaluate the effect of plasma rich in growth factors (PRGF), after a freeze-thawing cycle, on the proliferation and biological activity of progenitor cells involved in soft tissue healing. Different formulations of activated PRGF were added to hASCs cultured in serum-free medium. Cell proliferation was assessed by MTT test and cell count up to 7 and 12-day incubation. Osteo-differentiation ability of hASCs was also tested after 7 and 14-day incubation by alkaline phosphatase assay. The effects of 4 PRGF preparations (fresh/frozen and with/without platelets) were compared with corresponding formulations of plasma poor in growth factors and with standard medium. hASCs cultured in the presence of platelet concentrates increased proliferation rate with respect to cells grown in standard medium without significant differences among all the tested plasma formulations on cell viability up to 12 days of culture. PRGF activity is preserved after cryopreservation and platelet-rich preparations promoted osteo-differentiation of hASCs at day 7. In conclusion, PRGF supports the proliferation and the differentiation of progenitor cells in vitro also when applied after cryopreservation. Platelet concentrates, either alone or in combination with mesenchymal stem cells, might be a valuable tool in the field of tissue regeneration.

Plasma Rich in Growth Factors Improves Patients' Postoperative Quality of Life in Maxillary Sinus Floor Augmentation: Preliminary Results of a Randomized Clinical Study.

PURPOSE: The control of postoperative discomfort may improve the patient's quality of life as well as treatment acceptance. The aim of the present preliminary report was to assess if the use of autologous platelet concentrate during maxillary sinus augmentation may have a favorable impact on pain and other factors related to patient's quality of life in the first week after surgery. MATERIALS AND METHODS: This is an interim report of a randomized single-blind study. Fifteen patients with atrophic edentulous posterior maxilla underwent maxillary sinus augmentation using deproteinized bovine bone matrix (DBBM) as the grafting material (control group). In other 15 patients (test group), autologous plasma rich in growth factors (P-PRP) was added to DBBM, then a P-PRP clot was applied to covering the graft before suturing and finally P-PRP was placed over the suture in liquid form. During the first week postsurgery, all patients filled in a questionnaire for evaluation of main symptoms and daily activities. The outcomes of the questionnaires of the two groups were statistically compared. RESULTS: In the first days postsurgery, the group using P-PRP reported significantly less pain, swelling, and hematoma, and improved functional activities with respect to the control group. CONCLUSIONS: The adjunct of P-PRP to the maxillary sinus augmentation procedure produced a beneficial effect to patients' quality of life in the early postsurgical phase.