Synthetic Blocks for Bone Regeneration: A Systematic Review and Meta-Analysis

Abstract

This systematic review is aimed at evaluating the effectiveness of synthetic block materials for bone augmentation in preclinical in vivo studies. An electronic search was performed on Pubmed, Scopus, EMBASE. Articles selected underwent risk-of-bias assessment. The outcomes were: new bone formation and residual graft with histomorphometry, radiographic bone density, soft tissue parameters, complications. Meta-analysis was performed to compare new bone formation in test (synthetic blocks) vs. control group (autogenous blocks or spontaneous healing). The search yielded 214 articles. After screening, 39 studies were included, all performed on animal models: rabbits (n = 18 studies), dogs (n = 4), rats (n = 7), minipigs (n = 4), goats (n = 4), and sheep (n = 2). The meta-analysis on rabbit studies showed significantly higher new bone formation for synthetic blocks with respect to autogenous blocks both at four-week (mean difference (MD): 5.91%, 95% confidence intervals (CI): 1.04, 10.79%, p = 0.02) and at eight-week healing (MD: 4.44%, 95% CI: 0.71, 8.17%, p = 0.02). Other animal models evidenced a trend for better outcomes with synthetic blocks, though only based on qualitative analysis. Synthetic blocks may represent a viable resource in bone regenerative surgery for achieving new bone formation. Differences in the animal models, the design of included studies, and the bone defects treated should be considered when generalizing the results. Clinical studies are needed to confirm the effectiveness of synthetic blocks in bone augmentation procedures.

Primary Stability of Dental Implants in Low-Density (10 and 20 pcf) Polyurethane Foam Blocks: Conical vs Cylindrical Implants

“…The use of conical shaped implants could represent an advantage in cases of reduced diameter alveolar ridges [42][43][44][45].…”

Osseodensification Drilling vs. Standard Protocol of Implant Site Preparation: An In Vitro Study on Polyurethane Foam Sheets

“…The posterior region of the jaws is often associated with a decrease in bone quality causing the loss of teeth [22][23][24]. Implant positioning for oral rehabilitations of these regions could often represents a clinical challenge to obtain screw implant stability [10,25,26].…”

Wollastonite/TCP composites for bone regeneration: systematic review and meta-analysis

“…In spite of presenting some differences with the human bone anatomy and physiology, the rodents have been widely used in experimental research and contributed significantly to the development of new biomaterials and regenerative techniques, especially those aimed at bone regeneration [40,41]. This has been a model of choice for research that investigate biocompatibility and safety in the use of materials, such as [42,43]: biodegradation and bioresorption; carrying of drugs and/or active substances; osteoinduction, osteoconduction, and osteostimulation; osteogenic potential; and cell therapies associated with biomaterials. Despite the differences between rabbits and rodents, it is known that the use of small animals has numerous advantages over large ones, such as: better costbenefit; relatively short time of observation and rehabilitation; easy handling and manipulation of animals; standardization of experimental conditions among genetically similar individuals; easy reproducibility of study methods; and greater control of experimental conditions [40][41][42].…”

“…These characteristics highlight the potentiality of the polymeric mold impregnation method, also known as sponge replica method, considered highly effective and reproducible in the processing of 3D scaffolds, adopted by the studies that presented the highest percentages of NB in this meta-analysis (Table I) [12,13,18]. This method permits to obtain 3D scaffolds with a porous structure and a microarchitecture that enable the adhesion, migration, proliferation, and differentiation of distinct cell types, beyond promoting neovascularization at the implantation site, which favors the osteogenesis inside its 3D structure [1,2,4,5,22,42,49]. For this purpose, they need to present pores with at least 100 mm, although 300 mm is the most appropriate size for the aforementioned events, during bone neoformation inside the scaffolds [48].…”