The Impact of Nano-Hydroxyapatite Scaffold Enrichment on Bone Regeneration In Vivo-A Systematic Review.

OBJECTIVES: In order to ensure improved and accelerated bone regeneration, nano-hydroxyapatite scaffolds are often enriched with different bioactive components to further accelerate and improve bone healing. In this review, we critically examined whether the enrichment of nHAp/polymer scaffolds with growth factors, hormones, polypeptides, microRNAs and exosomes improved new bone formation in vivo. MATERIALS AND METHODS: Out of 2989 articles obtained from the literature search, 106 papers were read in full, and only 12 articles met the inclusion criteria for this review. RESULTS: Several bioactive components were reported to stimulate accelerated bone regeneration in a variety of bone defect models, showing better results than bone grafting with nHAp scaffolds alone. CONCLUSIONS: The results indicated that composite materials based on nHAp are excellent candidates as bone substitutes, while nHAp scaffold enrichment further accelerates bone regeneration. The standardization of animal models should be provided in order to clearly define the most significant parameters of in vivo studies. Only in this way can the adequate comparison of findings from different in vivo studies be possible, further advancing our knowledge on bone regeneration and enabling its translation to clinical settings.

Single nucleotide polymorphisms as a predisposing factor for the development of apical periodontitis-An umbrella review.

BACKGROUND: The interaction between heredity and different environmental factors in the modification of apical periodontitis (AP) susceptibility and prediction of its progression remain poorly elucidated. OBJECTIVES: This umbrella review aimed to (i) analyse the available relevant systematic reviews in an attempt to determine the association between genotype and allelic distribution of different single-nucleotide polymorphisms (SNPs) and the development of AP, (ii) report deficiencies and gaps in knowledge in this area and (iii) present recommendations to conduct future clinical studies and systematic reviews. METHODS: A literature search was conducted using Clarivate Analytics' Web of Science, Scopus, PubMed and Cochrane Database of Systematic Reviews, from inception to October 2021, with no language restrictions, including a grey literature search. Systematic reviews with/without meta-analysis evaluating genotype and allelic distribution of different SNPs between adult patients with/ without AP were included. All other type of studies were excluded. The methodological quality was assessed using the A MeaSurement Tool to Assess systematic Reviews (AMSTAR)-2 tool. Two independent reviewers were involved in study selection, data extraction and appraising the included reviews; disagreements were resolved by a third reviewer. RESULTS: The current study includes five systematic reviews. Three reviews performed meta-analysis. Three reviews were graded by AMSTAR 2 as 'critically low' quality, whereas the other two were graded as 'low' and 'moderate' quality. Two reviews indicated that carriers of specific genotypes and alleles of tumour necrosis factor-alpha (TNF-α) -308 G > A and interleukin 1-beta (IL-1ß) + 3954 C/T gene polymorphisms are more susceptible to an acute and persistent form of AP. However, high heterogeneity was observed. DISCUSSION: The statistical heterogeneity within included systematic reviews was a consequence of clinical and methodological diversity amongst primary studies. Although some of the included reviews suggested that carriers of specific genotype and/or allele of TNF-α -308 G > A and IL-1ß + 3954 C/T SNPs are more susceptible to AP, their conclusions should be interpreted with caution. CONCLUSIONS: No candidate genes could be identified as a definitive genetic risk or protective factor for the development and progression of AP, and further high-quality genome-wide association studies are warranted.

Methylation of tumour suppressor genes in benign and malignant salivary gland tumours: a systematic review and meta-analysis.

The aim of the present systematic review was to critically analyse the relationship between tumour suppressor genes (TSGs) promoter methylation, a potent mechanism of gene silencing, and the development of salivary gland tumours, as well as the possible effect on clinical/histological characteristics. Review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (registration ID CRD42020218511). A comprehensive search of Web of Science, Scopus, PubMed, and Cochrane Central Register of Controlled Trials was performed utilizing relevant key terms, supplemented by a search of grey literature. Newcastle-Ottawa Quality Assessment Scale (NOQAS) was used for the quality assessment of included studies. Sixteen cross-sectional and 12 case-control studies were included in the review, predominantly dealing with methylation in TSGs related to DNA repair, cell cycle, and cell growth regulation and differentiation. Quantitative synthesis could be performed on P16 (inhibitor of cyclin-dependent kinase 4a), RASSF1A (Ras association domain family 1 isoform A) and MGMT (O6-methylguanine DNA methyltransferase) genes only. It showed that P16 and RASSF1A genes were more frequently methylated in salivary gland tumours compared to controls (P = .0002 and P < .0001, respectively), while no significant difference was observed for MGMT. Additionally, P16 did not appear to be related to malignant transformation of pleomorphic adenomas (P = .330). In conclusion, TSG methylation is involved in salivary gland tumour pathogenesis and several genes might play a considerable role. Further studies are needed for a better understanding of complex epigenetic deregulation during salivary gland tumour development and progression.

Gene polymorphisms in odontogenic keratocysts and ameloblastomas: A systematic review.

OBJECTIVES: The aim of this systematic review was to critically analyze available data on gene polymorphisms in odontogenic keratocysts (OKC) and ameloblastomas, including their possible relationship with clinical and histological features of these lesions. MATERIALS AND METHODS: A comprehensive search of Web of Science Scopus, PubMed, Cochrane Central Register of Controlled Trials and EMBASE was conducted using relevant key terms and supplemented by a gray literature search. Quality assessment of included studies was performed using criteria from the Strengthening the Reporting of Genetic Association (STREGA) statement. RESULTS: Ten studies were included in the final review. Survivin -31G/C, interleukin IL-1α -889 C/T, p53 codon 72 G/C, tumor necrosis factor TNF-α (-308G>A) and its receptor TNF-R1 (36A>G), glioma-associated oncogene homolog 1 rs2228224 and matrix metalloproteinase 2 rs243865 gene polymorphisms were reported to be associated with OKC. For ameloblastomas, p53 codon 72 G/C, X-ray repair cross-complementing protein 1-codons 194 and 399 and matrix metalloproteinase 9 rs3918242 gene polymorphisms were identified as risk factors. It was not possible to establish a relationship between specific polymorphisms and clinical and histological features of investigated lesions. CONCLUSIONS: Several gene polymorphisms might be considered as a risk factor for the development of these lesions. Future studies should investigate whether these polymorphisms might be used to identify patients with increased risk of recurrence or aggressive disease.

Tumor Necrosis Factor Alpha -308 G/A Single-Nucleotide Polymorphism and Apical Periodontitis: An Updated Systematic Review and Meta-analysis.

INTRODUCTION: This study aimed to perform a more precise estimation of the association between tumor necrosis factor alpha (TNF-α) -308 G/A single-nucleotide polymorphism (SNP) and the risk of development of apical periodontitis (AP) and its phenotypes based on all available published studies. METHODS: The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and is registered in PROSPERO (CRD42020176190). The literature search was conducted via Clarivate Analytics Web of Science, Scopus, PubMed, Cochrane Central Register of Controlled Trials, and China National Knowledge Infrastructure databases from inception to December 2020 with no language restrictions. Two reviewers were involved independently in the study selection, data extraction, and appraising the studies that were included. The quality of the included studies was evaluated using the Strengthening the Reporting of Genetic Association and the Grading of Recommendations Assessment, Development and Evaluation system. The frequencies of the genotypes and alleles of the TNF-α (G>A 308, rs1800629) gene with 95% odds ratio were used. RESULTS: Four studies met the inclusion criteria with moderate risk of bias. This study revealed no significant association between TNF-α -308 G/A SNP and AP and the risk of AP development. Moreover, there was no significant association between genotype or allele frequency distribution and clinical manifestations (acute vs chronic) of AP. The certainty of evidence per the Grading of Recommendations Assessment, Development and Evaluation system was very low. CONCLUSIONS: Because of very low certainty of evidence, whether there is an association between TNF-α -308 G/A SNP and AP warrants further well-designed multicentric studies to adjudicate a better understanding of the role of genetic factors in the etiopathogenesis of AP.