Association between Periodontitis, Genetic Polymorphisms and Presence of Coronary Artery Disease in Southern Brazil / Relação entre Periodontite, Polimorfismos Genéticos e Doença Arterial Coronariana no Sul do Brasil

Abstract Background: Periodontitis and coronary artery disease (CAD) share an inflammatory etiology; there is a recent concern regarding the investigation of an association between these two conditions. Current theories indicate that cytokines and proteins have an important role in this process. C-reactive protein and interleukin-6 are inflammatory derivatives produced in the presence of periodontitis and in the pathophysiology of coronary disease. The polymorphisms of CRP + 1444 C > T and IL6-174 G > C are recognized in the literature as being related to CAD. Objective: This study investigates the association between periodontitis and coronary artery disease, through the presence of PCR and IL-6 polymorphisms. Methods: We selected 80 patients who underwent diagnostic catheterization in the HU of UFSM. The presence of periodontitis was determined by the Community Periodontal Index, whereas the CAD was established by the medical report. DNA was collected from a saliva sample and the presence of polymorphism was determined by PCR and restriction enzymes. A significance level of 5% was adopted. Results: The mean age of all participants (p = 0.035, OR 2.65; 95%CI: (1.02-6.87) male gender (p = 0.012, OR 3.37; 95% CI: (1.28- (p = 0.013, OR 3.66; 95% CI: (1.27-10.5)), PCR polymorphism + 1444C > T (p = 0.001, OR 6.37; 95% CI:, (2.25-17.9)) and IL6 -174 G > C polymorphism (p = 0.025, OR 2.87, 95% CI: (1.09-7.55)) were statistically associated with the presence of CAD. Age > 60 years and presence of the PCR +1444 C > T polymorphism remained independently associated with CAD after adjustment by logistic regression. Conclusions: The presence of the PCR + 1444 C > T polymorphism in this study was independently associated with the presence of coronary artery disease.

Resumo Fundamento: A periodontite e a doença arterial coronariana (DAC) compartilham uma etiologia inflamatória. Existe preocupação na investigação de associação entre essas duas condições. Há citocinas e proteínas com papel importante neste processo, como a proteína C-reativa (PCR) e a interleucina 6 (IL-6), que são derivados inflamatórios produzidos na presença da periodontite e na fisiopatologia da DAC. Os polimorfismos da PCR+1444 C > T e da IL-6 -174 G > C são reconhecidos na literatura como relacionados à DAC. Objetivo: Este estudo objetiva comprovar a associação entre periodontite e DAC, através da presença dos polimorfismos da PCR e da IL-6. Métodos: Foram selecionados 80 pacientes que se submeteram ao cateterismo diagnóstico no Hospital Universitário da Universidade Federal de Santa Maria (UFSM). A periodontite foi determinada pelo índice periodontal comunitário; a DAC, pelo laudo médico. Foi coletado o ácido desoxirribonucleico (DNA) pela saliva e estabelecido o polimorfismo pela avaliação da PCR/RFLP. Foi adotado um nível de significância estatística de 5%. Resultados: A idade mediana de todos os participantes (p = 0,035; OR 2,65; IC 95% [1,02-6,87]), gênero masculino (p = 0,012; OR 3,37; IC 95% [1,28-8,9]), periodontite (p = 0,013; OR 3,66; IC 95% [1,27-10,5]), polimorfismo da PCR +1444 C > T (p = 0,001; OR 6,37; IC 95% [2,25-17,9]) e polimorfismo da IL-6 -174G > C (p = 0,025; OR 2,87; IC 95% [1,09-7,55]) foram estatisticamente relacionados à DAC. Após ajuste com a regressão logística, mantiveram-se independentemente associadas à DAC a idade maior que 60 anos e o polimorfismo da PCR +1444 C > T. Conclusões: O polimorfismo da PCR +1444 C > T, neste estudo, esteve independentemente relacionado à DAC.

miR-9-1 gene methylation and DNMT3B (rs2424913) polymorphism may contribute to periodontitis

Abstract Genetic and epigenetic changes have been associated with periodontitis in various genes; however, little is known about genes involved in epigenetic mechanisms and in oxidative stress. Objective: This study aims to investigate the association of polymorphisms C677T in MTHFR (rs1801133) and −149C→T in DNMT3B (rs2424913), as well as the methylation profiles of MTHFR, miR-9-1, miR-9-3, SOD1, and CAT with periodontitis. The association between polymorphisms and DNA methylation profiles was also analyzed. Methodology: The population studied was composed of 100 nonsmokers of both sexes, divided into healthy and periodontitis groups. Genomic DNA was extracted from the epithelial buccal cells, which were collected through a mouthwash. Polymorphism analysis was performed through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), while methylation-specific PCR (MSP) or combined bisulfite restriction analysis techniques were applied for methylation analysis. Results: For DNMT3B, the T allele and the TT genotype were detected more frequently in the periodontitis group, as well as the methylated profile on the miR-9-1 promoter region. There was also a tendency towards promoter region methylation on the CAT sequence of individuals with periodontal disease. Conclusion: The polymorphism −149C→T in DNMT3B (rs2424913) and the methylated profile of the miR-9-1 promoter region are associated with periodontitis.

Upregulation of IL-10 expression inhibits the proliferation of human periodontal ligament stem cells

Abstract: The abnormal increase in proliferation rate of human periodontal ligament stem cells (PDLSCs) is considered to be involved in the pathogenesis of periodontitis, a disease in which the IL-10-mediated anti-inflammatory pathway plays a critical role. This study aimed to investigate the involvement of microRNA-466l in periodontitis and to explore the possible interaction between IL-10 and microRNA-466l. PDLSCs were obtained from periodontitis-affected teeth and healthy control teeth. The expression of microRNA-466l and IL-10 mRNA was measured in PDLSCs using RT-qPCR. The proliferation ability of PDLSCs was analyzed using CCK-8 assays. Overexpression of microRNA-466l in a PDLSC cell line was established using two different types of PDLSCs, and the effect of microRNA-466l overexpression on IL-10 expression and cell proliferation were detected by western blot and CCK-8 assays, respectively. We found that expression levels of microRNA-466l and IL-10 mRNA were significantly lower (P < 0.05) in PDLSCs derived from periodontitis-affected teeth compared to those derived from healthy teeth. However, the cell proliferation ability was significantly higher in the PDLSCs derived from periodontitis-affected teeth. Meanwhile microRNA-466l overexpression decreased cell proliferation rates of both types of PDLSCs and upregulated IL-10 expression. Together, these data suggest that microRNA-466l can upregulate IL-10 and reduce the proliferation rate of PDLSCs.

MMP13, TIMP2 and TGFB3 Gene Polymorphisms in Brazilian Chronic Periodontitis and Periimplantitis Subjects

Abstract Subjects susceptible to chronic periodontitis (CP) show a high risk for the development of peiimplantitis (PI). Both diseases are multifactorial, presenting similarities in their pathophysiology and polygenic profile. MMP-13 (matrix metalloproteinases 13/ collagenase 3) is a collagenolytic enzyme, which expression is induced by TGF beta 3 (transforming growth factor type 3) in human gingival fibroblasts and inhibited by TIMP-2 (tissue inhibitor of metalloproteinase type 2). The aim of this study was to investigate the occurrence of peiimplantitis (PI) in subjects with history of chronic periodontitis (CP) and polymorphisms frequency in MMP13, TIMP2 and TGFB3 genes. One hundred and sixty-three volunteers received dental implant placement were submitted to oral and radiographic examination in order to identify past history of CP or presence of PI. Volunteers were divided into 4 groups: Control (without PI and CP, n=72), CP (with CP and without PI, n=28), PI (with PI and without CP, n=28) and diseased (with CP and PI, n=35). The chi-square test correlated genotypes in specific regions of MMP13 (rs2252070), TIMP2 (rs7501477) and TGFB3 (rs2268626) genes, considering the interaction between CP and PI. The results showed that volunteers with CP had 3.2 times more susceptibility to develop PI (p=0.0004) compared to those without CP. No significant association was observed in MMP13, TIMP2 and TGFB3 genes with CP or PI. CP is a risk factor to develop PI, however, there is no association of both diseases with polymorphisms in the MMP13, TIMP2 and TGFB3 genes.

Resumo Indivíduos susceptíveis à periodontite crônica (CP) apresentam alto risco para o desenvolvimento de periimplantite (PI). Ambas doenças são multifatoriais e apresentam similaridades na patofisiologia e perfil poligênico. A MMP-13 (metaloproteinase da matriz tipo 13) é uma enzima colagenolítica cuja expressão é induzida por TGF beta 3 (fator transformador do crescimento tipo 3) nos fibroblastos gengivais humanos e inibida por TIMP-2 (inibidor tecidual de metaloproteinase tipo 2). O objetivo deste estudo foi investigar a ocorrência de periimplantite em sujeitos com periodontite crônica e a frequência dos polimorfismos nos genes MMP13, TIMP2 e TGFB3. Cento e sessenta e três voluntários submetidos à instalação de implantes endósseos foram analisados clínica e radiograficamente quanto à presença de histórico de CP e PI, sendo divididos em 4 grupos: Controle (sem história de CP e PI, n=72), CP (com CP e sem PI, n=28), PI (com PI e sem CP, n=28) e Doentes (com CP e PI, n=35). O teste do qui-quadrado correlacionou os genótipos nas regiões dos genes MMP13 (rs2252070), TIMP2 (rs7501477) e TGFB3 (rs2268626), considerando a interação entre CP e PI. Os resultados mostraram que voluntários com CP possuem 3.2 vezes mais chances de desenvolver PI (p=0.0004) comparados aos sem CP. Nenhuma associação significativa foi observada entre os genes MMP13, TIMP2 e TGFB3 e CP ou PI. A CP é um fator de risco ao desenvolvimento de PI, no entanto, não há associação entre ambas as doenças com polimorfismos nos genes MMP13, TIMP2 e TGFB3.

Maternal periodontitis induces intergenerational injuries on reproductive performance of adult female rat offspring / Periodontite materna induz prejuízos transgeracionais no desempenho reprodutivo da prole feminina na idade adulta

Substantial evidence suggests a direct link between periodontitis in pregnant women and subsequent adverse pregnancy outcomes. However, no studies have evaluated the transgenerational effects of periodontitis on the reproductive performance of subsequent generations. The present study investigated whether maternal periodontal disease exerts deleterious transgenerational effects on reproductive performance in F1 female rats. Rat female offspring from mothers that were subjected to experimentally induced periodontitis or sham operation were mated with sexually experienced male rats. The weight and reproductive performance of these F1 offspring were evaluated on gestation day 21, including maternal weight, litter weight, individual pup weight, number of pups, and number of resorptions. The percentage of dams with resorptions and the litter weight/number of pups were also calculated. Compared with the control group, an increase was observed in the percentage and number of resorptions and litter weight/number of pups, and a decrease was observed in the number of pups born in the experimental group. Maternal weight, litter weight, and individual pup weight were not different between the control and experimental groups. Maternal periodontitis impaired reproductive performance in the F1 generation. We showed that periodontitis may induce reproductive injury in adult offspring even if the offspring do not undergo any inflammatory/infectious process during their postnatal life or during gestation. These findings reinforce the importance of oral care during pregnancy.(AU)

Existem evidências substanciais de uma relação direta entre periodontite em mulheres grávidas com efeitos adversos reprodutivos. No entanto, nenhum estudo avaliou os efeitos intergeracionais da periodontite sobre o desempenho reprodutivo das gerações subsequentes. O presente estudo investigou se a doença periodontal materna exerce efeitos intergeracionais deletérios sobre o desempenho reprodutivo em ratos fêmeas da geração F1. Assim, filhas de ratas cujas mães foram submetidas a periodontite experimental ou falsamente operadas foram acasaladas com ratos machos sexualmente experientes. O peso corporal e desempenho reprodutivo da geração F1 foram avaliados no dia 21 de gestação, incluindo o peso materno, peso da ninhada, peso da individual dos filhotes, número de filhotes e de reabsorções. A percentagem de fêmeas com reabsorção e o peso da ninhada/número de filhotes também foram calculados. Comparados com o grupo controle, observou-se aumento na porcentagem e número de reabsorções e no peso da ninhada/ número de filhotes, e decréscimo no número de filhotes nascidos no grupo experimental. O peso materno, peso da ninhada e individual dos filhotes não foi diferente entre o controle e experimental. Estes resultados mostram que a periodontite experimental materna prejudica o desempenho reprodutivo da geração F1, mesmo que estes animais não tenham sido expostos diretamente a um processo inflamatório.(AU)

Cytokine gene polymorphism (interleukin-1β +3954, Interleukin-6 [−597/−174] and tumor necrosis factor-α −308) in chronic periodontitis with and without type 2 diabetes mellitus.

Background: Pro-inflammatory cytokine gene polymorphisms are potential candidates for susceptibility for both type 2 diabetes mellitus (DM) and chronic periodontitis (CHP). This study explored the association of interleukin‑1 beta (IL‑1 β) +3954, interleukin‑6 (IL‑6) −597/−174 and tumor necrosis factor‑alpha (TNF‑α) −308 single nucleotide polymorphisms in CHP with and without type 2 DM in Malayalam speaking subjects of Dravidian ethnicity. Materials and Methods: This case control study consisted of 51 chronic periodontitis with type 2 diabetes mellitus (CHPDM) and 51 CHP patients as cases and 51 healthy subjects as controls. Polymorphisms were identified by polymerase chain reaction amplification followed by restriction enzyme digestion and gel electrophoresis. Results: IL‑1 β (+3954) TT genotype and T allele were significantly associated with CHPDM group when compared with CHP (P = 0.001), whereas CC genotype and allele C was higher in CHP subjects (P = 0.001). For IL‑6 (−597) frequency of genotype GA/AA (P = 0.04) and allele A (P = 0.01) was lower in CHPDM group, and for TNF‑α −308 the frequency of genotype GA (P = 0.01) and allele A (P = 0.01) was higher in CHP subjects when compared with controls. Conclusions: In Malayalam speaking Dravidian population, IL‑6 (−597) genotype GA/AA and allele A appears to be protective for CHP with type 2 DM. Allele C of IL‑1 β +3954 and allele A of TNF‑α −308 appears to be risk factors for CHP individuals.

Genotipificación de los genes rgpA y kgp que codifican para las gingipaínas de Porphyromonas gingivalis / Genotyping of rgpA and kgp genes encoding Pophyromonas gingivalis gingipains

Porphyromonas gingivalis es un microorganismo fuertemente asociado con la etiología de la periodontitis. Esta bacteria posee varios factores de virulencia, dentro de los que destacan las gingipaínas, debido a sus múltiples acciones relacionadas con la destrucción de la matriz extracelular del tejido conectivo periodontal, la modulación del sistema inmune del hospedero y la estimulación de la expresión de citoquinas pro-inflamatorias. Estas proteinasas tienen afinidades específicas siendo Arg-gingipaínas (RgpA y RgpB, codificadas por los genes rgpA y rgpB, respectivamente) y Lys-gingipaínas (Kgp, codificada por el gen kgp). Se ha descrito que existen polimorfismos en los genes que codifican para esta proteinasas. El objetivo del presente estudio fue describir la frecuencia de los genotipos identificados para los genes rgpA y kgp en aislados clínicos de P. gingivalis, obtenidos desde pacientes con periodontitis. Para ello se utilizó amplificación por PCR de los genes rgpA y kgp, seguido de análisis de restricción. De un total de 47 aislados provenientes de 4 individuos con periodontitis crónica y 2 con periodontitis agresiva, se genotipificaron 38 aislados para el gen rgpA, exhibiendo la totalidad de éstos el patrón electroforético A (100 por ciento). Para el gen kgp se genotipificaron 43 aislados, presentando 28 de ellos (65.2 por ciento) el perfil electroforético kgp-I y 15 aislados (34.8 por ciento) el perfil kgp-II. En los aislados provenientes de un individuo fue posible apreciar ambos genotipos descritos para el gen kgp. Los resultados indican un predominio del patrón electroforético A (rgpA) y que el genotipo kgp-I fue el más frecuentemente encontrado de los genotipos kgp.

Porphyromonas gingivalis is a microorganism strongly associated with the etiology of periodontitis. This periodontal bacterium possesses an array of virulence factors, among which gingipains have a key importance, being involved with extracellular matrix destruction of periodontal tissues, modulation of host immune response and stimulation in the production of pro-inflammatory cytokines by different types of cells. These proteinases have specific affinities, being Arg-gingipains (RgpA and RgpB, encoded by rgpA and rgpB genes, respectively) and Lys-gingipains (Kgp, encoded by the kgp gene). It has been described that there are polymorphisms in the genes encoding for gingipains. Therefore, the aim of the present study was to describe the frequency of rgpA and kgp genotypes in clinical isolates of P. gingivalis obtained from periodontitis patients. For determining the rgpA and kgp genotypes, we used PCR amplification and restriction analysis. From 47 isolates obtained from 4 individuals with chronic periodontitis and 2 subjects with aggressive periodontitis, 38 were typified for rgpA gene and all exhibited the electrophoretic pattern A (100 percent). For kgp gene, we characterized 43 isolates, 28 of them (65.2 percent) with the kgp-I electrophoretic profile and 15 isolates (34.8 percent) with the kgp-II profile. In the isolates belonging to one individual, we found both genotypes of kgp gene. The results indicate a clear predominance of the electrophoretic pattern A (for rgpA gene) and kgp-I genotype was the most frequently found of the kgp genotypes.

Genetic polymorphisms in periodontal diseases: An overview.

Periodontitis is a multi-factorial disease; several risk and susceptibility factors are proposed in its natural history. Genetics is considered a susceptibility factor in relation to periodontitis. This article is a nonsystematic review of literature and focuses on the role of genetic polymorphisms in periodontal diseases.

Periodontal profile and presence of periodontal pathogens in young African-Americans from Salvador, BA, Brazil / Condição periodontal e presença de patógenos periodontais em uma população jovem de brasileiros afro-descendentes

This cross-sectional study evaluated the periodontal status and the presence of periodontopathogens in 132 young, black ethnic subjects who live in Salvador/Bahia-Brazil and have never smoked. Periodontal Probing Depth (PPD), Clinical Attachment Level (CAL), Plaque Index (PI) and Gingival Index (GI) were measured and analyzed by ANOVA and Wilcoxon tests (p<0.05) according to gender and age. The presence of A.actinomycetemcomitans, P.gingivalis, E.corrodens and F.nucleatum was determined by PCR and was analyzed by ANOVA, Wilcoxon, Student-t tests (p<0.05). Mean values of PPD and CAL were 2.18 and 1.0mm, respectively. Clinical parameters did not show differences between subjects of varying gender and age. The microbial prevalence was observed to be 95.45 percent for E.corrodens followed by F.nucleatum with 68.18 percent, A.actinomycetemcomitans with45.45 percent and P.gingivalis with 40.9 percent. An association between the presence of pathogens and gender and age was not observed (p<0.05). PPD, CAL and PI were not associated with P.gingivalis; however, GI appeared in higher frequencies among subjects without P.gingivalis. In this young, black ethnic, Brazilian population, a high percentage (96.96 percent) of subjects harbored at least one selected periodontal pathogen, but most subjects showed a healthy periodontal status. Further investigations are required to evaluate the actual influence of the presence of these bacterial species.

O objetivo do presente estudo foi avaliar a condição periodontal e presença de periodonto-patógenos em uma amostra de 132 jovens não fumantes, afro-descendentes, residentes em Salvador/Bahia-Brasil. Profundidade de Sondagem (PS), Nível Clínico de Inserção (NCI), Índice de Placa (IP) e Índice Gengival (IG) foram mensurados e analisados pelos testes ANOVA e Wilcoxon (p<0,05) em função do gênero e idade dos indivíduos. A. actinomycetemcomitans, P. gingivalis, E. corrodens e F. nucleatum foram identificados por PCR e analisados por ANOVA, Wilcoxon e t de Student (p<0,05). Foram observados valores médios de PS e NCI de 2,18 e 1,0mm respectivamente. Os parâmetros clínicos avaliados não sofreram influência dos fatores gênero e idade (p<0,05). E. corrodens foi a bactéria mais prevalente (95.45 por cento), seguido de F. nucleatum (68.18 por cento), A. actinomycetemcomitans (45.45 por cento) e P. gingivalis (40.9 por cento). Não foi observada associação entre os patógenos periodontais pesquisados com o gênero e idade dos indivíduos (p<0,05). PS, NCI e IP não estiveram associados a presença de P. gingivalis, todavia para o parâmetro IG este mostrou alta freqüência entre os indivíduos que não alocaram P. gingivalis. Nessa população jovem de brasileiros afro-descendentes um percentual (96,96 por cento) elevado de indivíduos apresentou pelo menos um patógeno periodontal, mas mostraram-se clinicamente saudáveis. Outras investigações são necessaries para avaliar a real influencia da presença dessas espécies bacterianas.

Analysis of vitamin D receptor gene polymorphisms in patients with chronic periodontitis.

BACKGROUND & OBJECTIVE: Genetic polymorphisms in the vitamin D receptor (VDR) gene are related to bone mineral density, bone turnover, and diseases with bone loss. Alveolar bone loss is a key feature in periodontitis. The aim of this study was to determine whether severe generalized chronic periodontitis (CP) in a Turkish population was associated with polymorphisms in the VDR gene. METHODS: Samples of venous blood and DNA were obtained from 72 patients with severe generalized chronic periodontitis and 102 healthy controls. The polymorphic regions were amplified using PCR followed by digestion with restriction enzymes BsmI A/G(rs1544410), ApaI G/T(rs11168271), TaqI T/C(rs731236), and analyzed electrophoretically. Genotype and allele frequencies were calculated. RESULTS: There were no statistically significant differences in the frequencies of VDR BsmI, ApaI, TaqI genotypes between the CP patients and healthy controls. The GTT haplotype, constructed from the three adjacent restriction fragment length polymorphisms was found to be over-represented among CP cases. This corresponded an OR of 2.4 (95% confidence interval, 1.12-5.18) for heterozygous carriers and 2.27 (95% confidence interval, 0.95-5.4) for homozygous carrier of the risk haplotype. INTERPRETATION & CONCLUSION: The present findings indicated that BsmI, ApaI, TaqI polymorphisms of the VDR gene were not associated with the severe generalized CP in the studied Turkish patients. Moreover, the VDR genotypes based on haplotype analysis may be associated with chronic periodontitis. In the future, diagnostic periodontal risk assessments like polymorphisms may be useful in detection of individuals susceptible for periodontitis.

Método alternativo de coleta de células para a extração de DNA e genotipagem dos polimorfismos de um único nucleotídeo através da tecnologia do chip em indivíduos com periodontite agressiva / An alternative method of cells collection for DNA extraction and single nucleotide polymorphisms genotyping using the chip technology in subjects with aggressive periodontitis

Vários estudos em genética humana têm utilizado a tecnologia do chip com múltiplos marcadores para a genotipagem de polimorfismos de único nucleotídeo (SNPs). Paralelamente, um número crescente de estudos busca a base molecular da predisposição à periondontite através dos polimorfismos. Os objetivos do presente estudo foram: testar um método alternativo de coleta de células de indivíduos com periodontite agressiva para a obtenção do DNA genômico; avaliar a qualidade do DNA extraído; testar sua utilização para genotipagem dos SNPs através da tecnologia do chip (Affymetrix GeneChip®10K, Santa Clara, CA). O método alternativo de coleta de células, além de menos invasivo mostrou-se adequado aos objetivos propostos.

A associação entre os polimorfismos de um único nucleotídeo e a periodontite agressiva / The association of single nucleotide polymorphisms and aggressive periodontitis

Vários estudos vêm demonstrando que as diferenças genéticas devem exercer um papel importante no risco de periodontite agressiva. A natureza familiar da doença tem sugerido que uma alteração genética principal seja a responsável por essa transmissão. Vários polimorfismos genéticos têm sido associados com a periodontite agressiva. A hipótese central tem sido que variações herdadas nos genes das citicinas determinam variações na resposta biológica ao estímulo autigênico, predispondo o paciente ao desenvolvimento da doença. A proposta deste estudo é revisar na literatura os principais estudos de associação genética de polimorfismos de um único nucleotídeo e a periodontite agressiva.

Papillon Lefevre Syndrome

Papillon-Lefevre syndrome is a very rare autosomal recessive condition characterised by pronounced palmoplantar hyperkeratosis and severe early onset periodontitis, leading to early loss of teeth. Here, we report a case of Papillon-Lefevre syndrome with a brief discussion on treatment aspect

Factores genéticos del huésped en las enfermedades periodontales / Host genetic factors in periodontal diseases

Hasta tiempos recientes, la periodoncia estuvo orientada a determinar las noxas externas, lo que determinó un oscurecimiento de la participación de otros factores, tales como el genético. El objetivo del presente artículo es brindar al lector una visión de la combinación de la perspectiva molecular de la genética con la de la patogenia de las enfermedades periodontales