Hyaluronic acid on collagen membranes: An experimental study in rats.

OBJECTIVE: The aim of this study was to evaluate the effect of hyaluronic acid (HA) in the structure and degradation patterns of BioGide® and OsseoGuard™ collagen membranes. HA mediates inflammation and acts in cell migration, adhesion, and differentiation, benefitting tissue remodeling and vascularization. These are desirable effects in guided regeneration procedures, but it is still unknown whether HA alters the barrier properties of absorbable membranes. DESIGN: Bone defects were created in the calvaria of rats, which were treated with HA gel 1% (HA group) or simply filled with blood clot (control group), and covered with BioGide® or OsseoGuard™. The animals were euthanized after 1, 30, and 60days, and their calvarias were processed for histological analysis. RESULTS: BioGide®, in both HA and control groups, showed vascularization, intense cell colonization, bone formation, and tissue integration at 30 and 60days. In contrast, Osseoguard™ presented minimal cellular colonization, and inflammatory reaction associated to foreign body reaction in both time points and groups. The HA group of BioGide® showed higher cell colonization (574.9±137.6) than the control group (269.1±70.83) at 60days (p<0.05). Despite this finding, the structure and degradation pattern were similar for BioGide® and Osseoguard™ in the HA and control groups. CONCLUSION: The results suggest that HA did not interfere with tissue integration and structural degradation of BioGide® and Osseoguard™ membranes.

Osteolipoma: a rare tumor in the oral cavity.

Osteolipoma is a rarely reported histologic variant of lipoma that exhibits bone formation. To the best of our knowledge, only 13 well-documented case reports of osteolipoma in the oral cavity have been published in the English literature. This study presents the clinical, radiographic, and histologic features of an osteolipoma in the oral cavity and reviews the pertinent literature. The patient was a 29-year-old female, who presented with an 8-month history of a painless, progressively enlarging, well-defined, movable submucosal mass in the left posterior buccal mucosa. The lesion had a hard consistency. Imaging findings revealed a spherical radiopacity with an irregular trabecular pattern. The lesion was excised and the diagnosis of osteolipoma was established. No recurrence was observed after a 5-year follow-up.

Morse taper internal connection implants: would abutment reseating influence retention?

Abstract Aim: To investigate whether the removal and reseating of the abutment influences the retention of Morse taper implant system. Methods: Two Morse taper implant systems were selected: Bicon Dental ImplantTM system (Bicon, LLC, Boston, MA, USA) and Kopp Implant(r) system (Kopp(r), Curitiba, PR, Brazil). In both systems, the abutment is connected to the implant with a locking taper. To seat the abutment, the same vertical force was applied in both systems. It was measured the compressive force necessary to engage effectively the locking taper connection and the tensile force to displace it. Results: The compressive force was determined by four activations in each abutment-implant set, and the sum of these forces was 21 N and 17 N in the BiconTM and Kopp(r) systems, respectively. Next, a tensile test was performed, revealing that the BiconTM system presented a 208 N resistance, whereas it was 194 N in the Kopp(r) system. Other three rounds of compression and tensile loads were applied, removing and reseating the abutment. We obtained the following tensile values: 367 N, 500 N and 756 N in the BiconTM System and 336 N, 360 N and 420 N in the Kopp(r) system. Conclusions: When the sets were subjected to repeated rounds of compressive and tensile forces, displacing and reseating the abutment, the tensile value increased.