Biological Effects of Bioresorbable Materials in Alveolar Ridge Augmentation: Comparison of Early and Slow Resorbing Osteosynthesis Materials

Abstract

The purpose of this study was to investigate the bone healing properties and histological environment of a u-HA/PLLA/PGA (u-HA—uncalcined and unsintered hydroxyapatite, PLLA—Poly L-lactic acid, PGA—polyglycolic acid) composite device in humans, and to understand the histological dynamics of using this device for maxillofacial treatments. Twenty-one subjects underwent pre-implant maxillary alveolar ridge augmentation with mandibular cortical bone blocks using u-HA/PLLA or u-HA/PLLA/PGA screws for fixation. Six months later, specimens of these screws and their adjacent tissue were retrieved. A histological and immunohistochemical evaluation of these samples was performed using collagen 1a, ALP (alkaline phosphatase), and osteocalcin. We observed that alveolar bone augmentation was successful for all of the subjects. Upon histological evaluation, the u-HA/PLLA screws had merged with the bone components, and the bone was directly connected to the biomaterial. In contrast, direct bone connection was not observed for the u-HA/PLLA/PGA screw. Immunohistological findings showed that in the u-HA/PLLA group, collagen 1a was positive for fibers that penetrated vertically into the bone. Alkaline phosphatase was positive only in the u-HA/PLLA stroma, and the stroma was negative for osteocalcin. In this study, u-HA/PLLA showed a greater bioactive bone conductivity than u-HA/PLLA/PGA and a higher biocompatibility for direct bone attachment. Furthermore, u-HA/PLLA was shown to have the potential for bone formation in the stroma.

Preparation, physicochemical characterization, and in vitro and in vivo osteogenic evaluation of a bioresorbable, moldable, hydroxyapatite/poly(caprolactone‐co‐lactide) bone substitute

“…(1) improper resorption rate, (2) insufficient integrity and stiffness to maintain contour, and (3) side effects of the by-products of bioresorbable bone substitute. 17,18 Balancing the rate of degradation and strength of bioresorbable materials is a critical problem for researchers who aim to expand their clinical applicability. PLA and its stereoisomers are the most widely used and researched types of aliphatic polyester materials because of their mechanical strength, modulus, and biocompatibility.…”

“…However, the application of bioresorbable bone substitute for bone augmentation in dental implantation is limited. The main reasons for this are as follows: (1) improper resorption rate, (2) insufficient integrity and stiffness to maintain contour, and (3) side effects of the by‐products of bioresorbable bone substitute 17,18 …”

In Vitro Assessment of the Cell Metabolic Activity, Cytotoxicity, Cell Attachment, and Inflammatory Reaction of Human Oral Fibroblasts on Polyetheretherketone (PEEK) Implant–Abutment

“…The shock-absorbing effect provided by PEEK might moderately absorb and disperse the impact under occlusion and chewing force, achieving a stress-dispersion mode like natural teeth [ 1 , 3 , 4 , 9 ]. Titanium osteosynthesis materials may cause complications over time and may need to be removed [ 14 ]; however, owing to the natural properties of PEEK, it can be used as a bone substitute in tissue engineering [ 15 ]. Thus, when applying PEEK as an alternative implant–abutment material to replace traditional materials, titanium alloy, or recent widely used materials, zirconium dioxide can be used as an implant–abutment material to reduce the risk of failure, eliminate concerns about metal allergies, and improve patient safety and esthetic satisfaction, thereby improving quality of life [ 10 , 16 ].…”