Matrix metalloproteinase-1 gene polymorphisms and periodontitis susceptibility: a meta-analysis based on 11 case-control studies

Host genetics role in the pathogenesis of periodontal disease and caries

BACKGROUND

This study aimed to produce the latest summary of the evidence for association of host genetic variants contributing to both periodontal diseases and caries.

MATERIALS AND METHODS

Two systematic searches of the literature were conducted in Ovid Medline, Embase, LILACS and Cochrane Library for large candidate gene studies (CGS), systematic reviews and genome-wide association studies reporting data on host genetic variants and presence of periodontal disease and caries.

RESULTS

A total of 124 studies were included in the review (59 for the periodontitis outcome and 65 for the caries outcome), from an initial search of 15,487 titles. Gene variants associated with periodontitis were categorized based on strength of evidence and then compared with gene variants associated with caries. Several gene variants showed moderate to strong evidence of association with periodontitis, although none of them had also been associated with the caries trait.

CONCLUSIONS

Despite some potential aetiopathogenic similarities between periodontitis and caries, no genetic variants to date have clearly been associated with both diseases. Further studies or comparisons across studies with large sample size and clear phenotype definition could shed light into possible shared genetic risk factors for caries and periodontitis.

Association of susceptible genotypes to periodontal disease with the clinical outcome and tooth survival after non-surgical periodontal therapy: A systematic review and meta-analysis

Background

The real clinical utility of genetic testing is the prognostic value of genetic factors in the clinical outcome of periodontal treatment and the tooth survival. A meta-analysis was undertaken to estimate the effect of a susceptible genotype to periodontitis on the clinical outcomes of non-surgical periodontal therapy and the tooth survival.

Material and Methods

A systematic search of MEDLINE-Pubmed, Cochrane Library and Scopus was performed. Additionally, a hand search was done in three journals. No specific language restriction was applied. Two reviewers screened independently titles and abstracts or full text copies. Quality assessment of all the included studies was held.

Results

Initial screening of electronic databases resulted in 283 articles. Ten studies met the inclusion criteria, nine of them examined the clinical outcome, while the other one investigated the tooth survival in susceptible individuals after non-surgical periodontal therapy. Eight of included studies were selected for the meta-analysis. IL-1 positive genotypes increase the risk of tooth loss, while no association found between the bleeding on probing (BOP), clinical attachment loss (CAL) and plaque index (PI) with the genotype status. Probing pocket depth (PPD) reduction in the first three months and in long-term results found to have a significant association with the genotype.

Conclusions

There is no difference in the clinical measurements after non-surgical periodontal treatment, apart from PPD. More publications are needed to identify a cause-effect relationship.

Key words:Periodontal disease, periodontitis, periodontal therapy, clinical outcome, tooth loss, susceptibility, polymorphism, genotype, meta-analysis, systematic review.

Uncovering the molecular networks in periodontitis

Periodontitis is a complex immune-inflammatory disease that results from a preestablished infection in gingiva, mainly due to Gram-negative bacteria that colonize deeper in gingival sulcus and latter periodontal pocket. Host inflammatory and immune responses have both protective and destructive roles. Although cytokines, prostaglandins, and proteases struggle against microbial burden, these molecules promote connective tissue loss and alveolar bone resorption, leading to several histopathological changes, namely destruction of periodontal ligament, deepening of periodontal pocket, and bone loss, which can converge to attain tooth loss. Despite the efforts of genomics, transcriptomics, proteomics/peptidomics, and metabolomics, there is no available biomarker for periodontitis diagnosis, prognosis, and treatment evaluation, which could assist on the established clinical evaluation. Nevertheless, some genes, transcripts, proteins and metabolites have already shown a different expression in healthy subjects and in patients. Though, so far, 'omics approaches only disclosed the host inflammatory response as a consequence of microbial invasion in periodontitis and the diagnosis in periodontitis still relies on clinical parameters, thus a molecular tool for assessing periodontitis lacks in current dental medicine paradigm. Saliva and gingival crevicular fluid have been attracting researchers due to their diagnostic potential, ease, and noninvasive nature of collection. Each one of these fluids has some advantages and disadvantages that are discussed in this review.

Four tumor necrosis factor alpha genes polymorphisms and periodontitis risk in a Chinese population

BACKGROUND

Tumour necrosis factor-alpha (TNF-alpha) has been implicated in the pathogenesis of generalized aggressive periodontitis (AgP) and chronic periodontitis (CP). The objective of the present study was to evaluate the association of four TNF-alpha gene polymorphisms (-1031T/C, -857C/T, -308G/A and -238G/A) with susceptibility to AgP and CP in a Chinese population.

METHODS

A hospital-based case-control study was conducted in in patients with CP (n = 180), AgP (n = 180) and healthy controls (n = 180). Gene promoter polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Genotype and allele frequencies were analyzed using the chi-square test and logistic regression analysis.

RESULTS

TNF-alpha -1031CC genotype was significantly higher [odds ratio (OR) = 2.36, 95% confidence interval (CI) = 1.03, 5.43; P = 0.04] in patients with CP compared with healthy controls. TNF-alpha -308AA genotype was significantly higher (OR = 2.71, 95% CI = 1.09, 6.73; P = 0.03) in patients with AgP compared with healthy controls. No association was found of TNF-alpha -857C/T and -238G/A polymorphisms with susceptibility to AgP or CP.

CONCLUSIONS

Our data demonstrated that TNF-alpha -1031CC genotype was a risk factor for CP, and that TNF-alpha -308AA genotype was a risk factor for AgP. But there is a lack of association of TNF-alpha -857C/T and -238G/A polymorphisms with susceptibility to AgP or CP in a Chinese population.