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The aims of the present study were to clinically and histologically evaluate human fresh frozen bone (FFB) grafts used to treat severe maxillary horizontal defects prior to dental implant placement. Ten patients were treated with FFB onlay grafts. Measurements using computed tomography scans were recorded preoperatively and at 5 months. Six core biopsies were retrieved and processed for light microscopy. At baseline, thickness of the maxillary alveolar ridge measured 2.3 +/- 0.4 mm; it measured 6.8 +/- 0.5 mm after reconstruction. All implants were successful after 24 months. Histologic results showed that FFB blocks and new bone were integrated perfectly. Histomorphometry revealed a mean percentage of bone of 57.5% +/- 24.7%. (Int J Periodontics Restorative Dent 2011; 31:535-544.)

AIM: To evaluate the growth of Human Gingival Fibroblasts (HGFs) cultured onto sample discs of CAD/CAM zirconia and veneering ceramic for zirconia by means of Scanning Electron Microscope (SEM) analysis at different experimental times. METHODS: A total of 26 experimental discs, divided into 2 groups, were used: Group A) CAD/CAM zirconia (3Y-TZP) discs (n=13); Group B) veneering ceramic for zirconia discs (n=13). HGFs were obtained from human gingival biopsies, isolated and placed in culture plates. Subsequently, cells were seeded on experimental discs at 7,5×10(3)/cm(2) concentration and cultured for a total of 7 days. Discs were processed for SEM observation at 3h, 24h, 72h and 7 days. RESULTS: In Group A, after 3h, HGFs were adherent to the surface and showed a flattened profile. The disc surface covered by HGFs resulted to be wider in Group A than in Group B samples. At SEM observation, after 24h and 72h, differences in cell attachment were slightly noticeable between the groups, with an evident flattening of HGFs on both surfaces. All differences between Group A and group B became less significant after 7 days of culture in vitro. CONCLUSIONS: SEM analysis of HGFs showed differences in terms of cell adhesion and proliferation, especially in the early hours of culture. Results showed a better adhesion and cell growth in Group A than in Group B, especially up to 72h in vitro. Differences decreased after 7 days, probably because of the rougher surface of CAD/CAM zirconia, promoting better cell adhesion, compared to the smoother surface of veneering ceramic.

Objectives. The present in vitro study aimed at evaluating the fracture resistance of both implant-supported screw- and cement-retained porcelain fused to metal (PFM) single crowns. A scanning electron microscope (SEM) evaluation of the mode of failure of the spec- imens was also performed. Methods. Forty PFM premolar-shaped identical single crowns were realized. The restorations were divided into two groups: cement-retained (group 1) and screw-retained (group 2) pros- theses. Compressive loading tests and SEM fractographic analyses were performed. The data were statistically analysed by means of the Student’s t-test, with a confidence interval of 95%. Results. The mean fracture load value was 1657 (±725) N in group 1 and 1281 (±747) N in group 2; the statistical analysis pointed out no significant differences between the two groups (p = 0.115). The mean work at maximum load value was 0.775 (±0.619) J in group 1 and 0.605 (±0.526) J in group 2; the statistical analysis pointed out no significant differences between the two groups (p = 0.355). All the samples were affected by cohesive fractures of the porcelain. Screw-retained crowns showed microcracks at the level of the occlusal access to the screw and extensive fractures in the whole thickness of the ceramics. On the contrary, cement-retained restora- tions were affected by less wide paramarginal fractures of the porcelain. Significance. A stronger implant-prosthetic connection was noticed in cemented restora- tions group than in screw-retained single crowns. Even though negatively influenced by the presence of the occlusal access to the screw, the metal–ceramics bond can be considered predictable in both the implant-prosthetic connection systems analysed.

Mesenchymal stem cells from periodontal ligament (PDL-MSCs) hold great promise for bone regeneration. Most studies regarding the osteogenic differentiation of stem cells from periodontal tissue suggest that PDL cells may have many osteoblast-like properties, including the ability to form calcified nodules in vitro. This study investigated the morphological and histochemistry aspects of human PDL-MSCs, induced for osteogenic differentiation and seeded on a xenogenic porcine bone substitute in vitro, at different times of incubation. This biomaterial seems physically identical to human bone, and it has been reported to be osteoconductive. Our results indicated that the cells had a high affinity for the three-dimensional biomaterials; in fact, cellular proliferation and colonization was evident, and after 21 days the adherent cells started to detach themselves from the substrate, and at 30 days of incubation in differentiation medium, the cells completely lost the adhesion to the Petri's disk, englobing all bioparticles. In conclusion, the in vitro behaviour of PDL-MSCs and their relationship with three-dimensional scaffold biomaterials encourage in vivo investigations for their use in dental tissue regeneration.

Background: The purpose of the present study was the clinical and the histologic evaluation of fresh frozen human bone (FFB) allografts used for maxillary sinus-augmentation procedures. Methods: Ten subjects were treated with maxillary sinus augmentations using FFB. Radiologic measurements were recorded on computed tomography scans preoperatively and 5 months after the sinus surgeries. At 5 months, during implant placement, 10 core biopsies were retrieved and processed for histomorphometric evaluation under light microscopy (LM). Clinical and histomorphometric measurements are presented as mean SD. Results: At baseline, the height of the alveolar ridge measured 4.3 +/- 1.3 mm (mean); after augmentation procedures, at implant positioning, it had a mean height of 16.0 +/- 1.8 mm. All 22 dental implants were clinically healthy after 5 months. LM showed that most of the specimens presented newly formed bone that was completely integrated with preexisting bone. The interface areas between new and old bone were not discernible. Woven bone was present in some areas of the biopsies; however, in the majority of the examined regions, there was mature osseous tissue presenting features of trabecular bone. There was no evidence of an acute inflammatory infiltrate. Histomorphometry revealed that the percentage of bone was 48.15% +/- 14.32%, whereas marrow spaces occupied the rest of the area. Conclusion: FFB is a biocompatible material that can be successfully used for maxillary sinus augmentations without interfering with normal reparative bone processes.

SUMMARY This study, performed using a specially designed apparatus that included 10 aligned brackets, evaluated the frictional resistance generated by conventional stainless steel (SS) brackets (Victory Series), self-ligating Damon SL II brackets, Time Plus brackets, and low-friction ligatures (Slide) coupled with various SS, nickel-titanium (NiTi), and beta-titanium (TMA) archwires. All brackets had a 0.022-inch slot and the orthodontic wire alloys were 0.016, 0.016 × 0.022, and 0.019 × 0.025 inch NiTi, 0.017 × 0.025 inch TMA, and 0.019 × 0.025 inch SS. Each bracket – archwire combination was tested 10 times. Coupled with 0.016 inch NiTi, Victory brackets generated the most friction and Damon SL II the least ( P < 0.001); with 0.016 × 0.022 inch NiTi, the self-ligating brackets (Time and Damon SL II) generated signifi cantly lower friction ( P < 0.001) than Victory Series and Slide ligatures; with 0.019 × 0.025 inch SS or 0.019 × 0.025 inch NiTi, Slide ligatures generated signifi cantly lower friction than all other groups. No difference was observed among the four groups when used with a 0.017 × 0.025-inch TMA archwire. These fi ndings suggest that the use of an in vitro testing model that includes 10 brackets provides information about the frictional force of the various bracket – archwire combinations.

Peri-implantitis may occur because of biologic or mechanical factors. They can be treated by a variety of methods. Aim of the present study was to evaluate implant surface of failed oral titanium implants after irradiated with ErCR:YSGG 2780 laser. This study comprised 45 implants removed for peri-implantitis reasons. The implants were divided into two groups: group I (Control): 22 non-irradiated implants, group II (Test): 23 irradiated implants. Immediately after extraction, the second group's implants were irradiated with an ErCR: YSGG 2780 laser (Waterlase MD Turbo-Biolase). Control and test implants were processed with SEM analysis. At higher magnification in the coronal portion no bacteria were found on test implant surface. At low magnification, there was a variation in the number of fields of deposit among the non-irradiated implants and different portions on the same implants. At higher magnification, deposits were identified as connective tissue in apical portion and bacteria or others, in coronal portion of control implants. In conclusion, ErCR:YSGG 2780 laser is recommended to be used in implant surface detoxification without any surface alteration, using the experimental conditions.

Objectives: This in vitro study evaluated the friction (F) generated by aligned stainless steel (SS) conventional brackets, self-ligating Damon MX© brackets (SDS Ormco, Glendora, California, USA), Time3© brackets (American Orthodontics, Sheboygan, Wisconsin, USA), Vision LP© brackets (American Orthodontics), and low-friction Slide© ligatures (Leone, Firenze, Italy) coupled with various SS, nickel-titanium (NiTi), and beta-titanium (TMA) archwires. Methods: All brackets had a 0.022-inch slot, and the orthodontic archwires were 0.014-inch, 0.016-inch, 0.014×0.025-inch, 0.018×0.025-inch, and 0.019×0.025-inch NiTi; 0.017×0.025-inch TMA; and 0.019×0.025-inch SS. Each bracket-archwire combination was tested 10 times. In the test, 10 brackets of the same group were mounted in alignment on a metal bar. The archwires moved through all the 10 brackets at a crosshead speed of 0.5 mm/min (each run lasted approximately 5 min). The differences among 5 groups of brackets were analyzed through the Kruskal-Wallis test, and a Mann-Whitney test was calculated as post hoc analysis. The P value was set at 0.05. Results: Coupled with 0.014-inch NiTi and 0.016-inch NiTi, Victory Series© brackets generated the greatest F, while Damon MX© and Vision LP© brackets generated the lowest (P