Effects of Vitamin and Amino Acid-Enriched Hyaluronic Acid Gel on the Healing of Oral Mucosa: In Vivo and In Vitro Study

Background and Objectives: Wound healing is a dynamic process that can be compromised in patients with chronic and metabolic conditions or unhealthy lifestyles. Numerous medical substances designed for topical use, charged with compounds that promote the healing process, have been developed to improve wound healing, especially in compromised subjects. The present study aimed to extend our understanding of the in vivo effects of a hyaluronic acid gel charged with amino acids (HAplus gel, Aminogam gel® Errekappa Euroterapici spa, Milan, Italy) and study the in vitro effects of the same gel charged with additional substances in an attempt to optimize its formulation. Materials and Methods: In a randomized controlled split-mouth clinical and histological trial, HAplus gel was tested on the gingival tissue of the lower third molar post-extraction socket. The gingiva was collected at the time of extraction (T0) and ten days after the extraction (T1) to be histologically analyzed. During the second stage of the study, culture media with HAplus gel and vitamin C and E at different concentrations (TEST) were tested on human gingival fibroblasts and compared to the HAplus-enriched medium (HA-Control). Results: Histological and immunohistochemical analysis of collected gingiva showed higher microvascular density and collagen fibers organized in closely packed and well-oriented bundles in sites treated with HAplus gel. In the in vitro study, all TEST groups showed an increased viability from 24 h to 48 h. After 24 h, the viability percentage in all experimental groups was below 100% of the HA-Control, demonstrating a mild toxicity. After 48 h from seeding, the TEST groups’ viability grew significantly compared to HA-Control. Conclusions: These encouraging preliminary results suggest that the use of HAplus gel enriched with vitamins C and E may be beneficial in patients with conditions that impair soft tissue healing

Maxillary sinus lift with or without biomaterials in humans: radiographic and histomorphometric evaluation

Biomaterials are frequently used for sinus lift procedures at the time of implant installation in the posterior upper jaw. Nevertheless, some authors have reported the possibility of leaving an empty space, in order to exploit the regenerative potential of the residual periosteal and bony walls following the Schneiderian membrane elevation. The aim of this study was to compare the radiographic changes and histological characteristics of newly formed bone following sinus lift without any biomaterials or Bio-Oss®. Fifteen patients with edentulousness of the maxillary molar-premolar area and a residual crest thickness < 6 mm, were randomly allocated to a test group (sinus lift without biomaterial) or a control group (with Bio-Oss®). Two submerged Astra Tech implants were placed in the most mesial and distal portion of the augmented area. Six months later, a bone biopsy was harvested in the area between the 2 previously placed fixtures, where a third central implant was placed. Standard radiographies were taken before sinus lift and 6 months later in order to measure and compare the vertical bone changes. The biopsies were processed for ground sectioning. All implants but one case were successful. Radiographically, the basic level of bone tissue in the test group (n=5) was 5 ± 0.86 mm and 3.5 ± 0.57 mm in the control group (n=10); in the test group the bone tissue was increased vertically of 10 ± 2.53 (range 7-13), in the control group 13 ± 1.41 (range 12-14). At histological observation, all samples showed new bone formation without signs of inflammation. Bone remodeling was observed in the apical portion of both groups. Residual particles of biomaterial were embedded in mineralized new bone. Histometric results for the control group were: LB 38.8% ± 8.1, WB 9.2% ± 2.4, BM 30.2% ± 7.5, BO 21.7% ± 8.9; for the test group: LB 54.5% ± 2.1, WB 115.5% ± 6.1 and BM 33.5% ± 6.4. A clinically significant bone increase was achieved both with and without the use of biomaterials. The implants showed similar performances when inserted at sites augmented with or without biomaterials. The success of such procedure might depend on the anatomical conformation of the crest and on the level of surgical experience of the surgeon