Toxicity and cytokine release from human dental pulp stem cells after exposure to universal dental adhesives cured by single peak and polywave LEDs.

OBJECTIVES: to assess the impact of universal adhesives, cured with single-peak and polywave LEDs, on the metabolic activity and cytokine release of human dental pulp stem cells (hDPSCs). In addition, analyze the degree of conversion (DC) of the adhesives cured with the different LEDs. METHODS: Discs (5 mm diameter, 1 mm thick) were prepared using three universal adhesives: Single Bond Universal (SBU, 3 M ESPE), Optibond Universal (OBU, Kerr), and Zipbond Universal (ZBU, SDI). These discs were cured for 40 s using a single-peak (DeepCure, 3 M ESPE) or a polywave light-emmiting diode (LED) curing unit (Valo Grand, Ultradent). After 24 h, the specimens were placed in 24-well culture plates, each containing 1 mL of culture medium for 24 h. hDPSCs (1.8 ×104) were seeded in 96-well plates and allowed to grow for 24 h. Subsequently, the cells were exposed to the extracts (culture medium containing eluates from the adhesive discs) for an additional 24 h. Cells not exposed to the extracts were used as a control group. The mitochondrial metabolism was assessed using the MTT assay and the cytokine release evaluated through MAGPIX. The degree of conversion of the adhesives was analyzed using FTIR (n = 5). The results were analyzed by ANOVA two-way and Tukey's test. RESULTS: OBU and ZBU eluates caused a statistically significant reduction in mitochondrial metabolism, regardless of the LED used, indicating their cytotoxicity. In contrast, SBU did not significantly affect the MTT results, resembling the control group. A higher release of cytokines IL-1, IL-6, IL-10, and TNF-α were found in association to ZBU. SBU, on the other hand, increased the release of IL-8. OBU did not influenced the cytokine release. SBU presented the higher DC, while OBU and ZBU had similar DC, lower than SBU. SIGNIFICANCE: In conclusion, universal adhesives exhibit toxicity towards hDPSCs, but the extent of toxicity varies depending on the adhesive material. ZBU was associated with increased cytokine release, particularly pro-inflammatory mediators, from hDPSCs. The different LEDs did not influenced the cytotoxicity of the evaluated adhesives.

MicroRNA biogenesis machinery activation and lncRNA and REST overexpression as neuroprotective responses to fight inflammation in the hippocampus.

Brain Long non-coding RNA (lncRNA) and microRNAs (miRs) play essential roles in the regulation of several important biological processes, including neuronal activity, cognitive processes, neurogenesis, angiogenesis, and neuroinflammation. In this context, the transcriptional repressor, RE1 silencing transcription factor (Rest), acts regulating the expression of neuronal genes as well as of lncRNAs and multiple miRNAs in the central nervous system. Nevertheless, its role in neuroinflammation was less explored. Here, we demonstrate, using an in vivo model of neuroinflammation induced by i.p. injection of LPS (0.33 mg/kg), that neuroinflammation increases gene expression of pro-inflammatory cytokines concomitant with the native and truncated forms of Rest and of non-coding RNAs. Additionally, the increased expression of enzymes Drosha ribonuclease III) (Drosha), Exportin 5 (Xpo5) and Endoribonuclease dicer (Dicer), associated with high expression of neuroprotective miRs 22 and 132 are indicative that the activation of biogenesis of miRs in the hippocampal region is a Central Nervous System (CNS) protective mechanism for the deleterious effects of neuroinflammation. Our results indicate that positive regulation of Rest gene expression in the hippocampal region by neuroinflammation correlates directly with the expression of miRs 22 and 132 and inversely with miR 335. In parallel, the confirmation of the possible alignment between the lncRNAs with miR 335 by bioinformatics corroborates with the sponge effect of Hottip and Hotair hybridizing and inhibiting the pro-inflammatory action of miR 335. This suggests the existence of a possible correlation between the activation of miR biogenesis machinery with increased expression of the transcription factor Rest, contributing to neuroprotection.

Co-initiators of polymerization can modulate the inflammatory cytokine release without major cytotoxic effects in human dental pulp cells.

To evaluate the cytotoxicity of co-initiators of polymerization and its influence on cytokine release from human dental pulp cells (hDPCs). Cells were isolated from the dental pulp of sound human third molars. The co-initiators dimethylaminoethyl amine benzoate-(EDAB), 2-(dimethylamino)ethyl methacrylate (DMAEMA); 2-Ethylhexyl 4-(dimethylamino)benzoate (EHA) and bis(4-methyl phenyl)iodonium hexafluorophosphate (BPI) were diluted in dimethylsulfoxide (DMSO) at different concentrations. In this way, experimental groups and one control (without treatment) were obtained. hDPCs (10 × 104 cell per well) were seeded on 96 well plates and incubated at 37°C and 5% CO2 for 48 h. After this, the cells were exposed to different concentrations of co-initiators cited for 24 h. After this time, the culture medium was removed, and the mitochondrial metabolism was evaluated by MTT assay, cell death by flow cytometry, and cytokine released (IL-1ß, IL6, IL-8, IL-10, and TNF-α) was analyzed by MAGPIX assay. The data were analyzed by ANOVA one-way and Tukey's test. EHA, DMAEMA, and EDAB did not reduce the mitochondrial metabolism. BPI presented high toxicity with remarkable reduction (80%) after exposure to 1 mM. The cell death of all test groups was similar to control. After 24 h treatment, the IL-8 was up-regulated by all compounds, while IL-6 was upregulated after exposure to EHA and downregulated after DMAEMA stimulation. BPI, EHA, EDAB, and DMAEMA can trigger an initial inflammatory response, upregulating the IL-8 secretion in hDPCs in a compound-concentration-dependent manner; however, this was not accompanied by major cytotoxic effects at cell death or mitochondrial-metabolism levels.

Impact of neuroinflammation on epigenetic transcriptional control of Sonic Hedgehog members in the central nervous system.

Sonic Hedgehog (Shh) signaling plays a critical role during central nervous system (CNS) development, and its dysregulation leads to neurological disorders. Nevertheless, little is known about Shh signaling regulation in the adult brain. Here, we investigated the contribution of DNA methylation on the transcriptional control of Shh signaling pathway members and its basal distribution impact on the brain, as well as its modulation by inflammation. The methylation status of the promoter regions of these members and the transcriptional profile of DNA-modifying enzymes (DNA Methyltransferases - DNMTs and Tet Methylcytosine Dioxygenase - TETs) were investigated in a murine model of neuroinflammation by qPCR. We showed that, in the adult brain, methylation in the CpG promoter regions of the Shh signaling pathway members was critical to determine the endogenous differential transcriptional pattern observed between distinct brain regions. We also found that neuroinflammation differentially modulates gene expression of DNA-modifying enzymes. This study reveals the basal transcriptional profile of DNMTs and TETs enzymes in the CNS and demonstrates the effect of neuroinflammation on the transcriptional control of members of the Shh Signaling pathway in the adult brain.

Human periodontal ligament stem cells with distinct osteogenic potential induce bone formation in rat calvaria defects.

Aim: This study aimed to evaluate the ability of human periodontal ligament stem cells (PDLSCs) with high (HP-PDLSCs) and low (LP-PDLSCs) osteogenic potential, in addition to mixed cells, to repair bone tissue. Methods: Cell phenotype, proliferation and differentiation were evaluated. Undifferentiated PDLSCs were injected into rat calvarial defects and the new bone was evaluated by µCT, histology and real-time PCR. Results: PDLSCs exhibited a typical mesenchymal stem cell phenotype and HP-PDLSCs showed lower proliferative and higher osteogenic potential than LP-PDLSCs. PDLSCs induced similar bone formation and histological analysis suggests a remodeling process, confirmed by osteogenic and osteoclastogenic markers, especially in tissues derived from defects treated with HP-PDLSCs. Conclusion: PDLSCs induced similar bone formation irrespective of their in vitro osteogenic potential.

Bone is one of the most transplanted tissues worldwide and cell-based therapies has been investigated as an alternative for the treatment of bone defects. Dental tissues have been investigated as sources of stem cells and the periodontal ligament has been shown to be a viable source of these cells. Stem cells from periodontal ligament induce significant bone formation in rat calvaria defects and are safe for cell-based therapies, as the cells remain at the bone defect site for up to 4 weeks and do not migrate to vital organs, such as brain, heart, lungs, spleen, kidneys, and liver in the same period. In addition, immune responses were not detected. Considering that, stem cells from periodontal ligament can be useful in cell therapy strategies to induce bone regeneration.

BMP-2 and asporin expression regulate 5-aza-dC-mediated osteoblast/cementoblast differentiation of periodontal dental ligament mesenchymal progenitor cells.

Periodontal dental ligament (PDL) is composed of heterogeneous population of mesenchymal progenitor cells. The mechanisms that regulate the differentiation of these cells towards osteoblast/cementoblast phenotype are not fully understood. Some studies have demonstrated that is possible to change the pattern of cell differentiation via epigenetic mechanisms. The proposal of this study was to investigate whether 5-aza-2'-deoxycytidine (5-aza-dC) treatment would stimulate the osteoblast/cementoblast differentiation of periodontal ligament mesenchymal progenitor cells (PDL-CD105+ enriched cells), characterized as low osteoblast potential, through bone morphogenetic protein-2 (BMP-2) modulation. PDL-CD105+ cells from a single donor were cloned and characterized in two populations as high osteoblast/cementoblast potential (HOP) and low osteoblast/cementoblast potential (LOP) by mineralization in vitro and expression of osteogenic gene markers, such as runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteocalcin (OCN), bone morphogenetic protein 2 (BMP-2) and asporin (ASPN). Next, two LOP clones (L1 and L2) were pretreated with 5-aza-dC (10 µM) for 48 h, cultured under osteogenic condition and evaluated for mineralized matrix in vitro, transcription modulation of osteogenic gene markers, methylated and hydroxymethylated DNA levels of BMP-2 and ASPN and intracellular/extracellular expression of BMP-2 protein. LOP clones showed high expression of ASPN transcripts associated with low mRNA levels of BMP-2, RUNX2, ALP, and OCN. 5-aza-dC treatment raised hydroxymethylated DNA levels of BMP-2 and increased the expression of BMP-2 transcripts in both LOP clones. However, BMP-2 protein (intracellular and secreted forms) was detected only in L1 cell clones, in which it was observed an increased expression of osteoblast/cementoblast markers (RUNX2, ALP, OCN) associated with higher mineralization in vitro. In L2 cell clones, 5-aza-dC increased gene expression of ASPN, with no great change in for osteoblast/cementoblast differentiation potential. These data show that 5-aza-dC improves osteoblast/cementoblast differentiation of PDL-CD105+ cells via BMP-2 secretion, and this effect depends on low levels of ASPN expression.

Protocols for Genetic and Epigenetic Studies of Rare Diseases Affecting Dental Tissues.

This chapter describes methods related to the diagnosis of genetic dental diseases. Based on the present knowledge, clinical phenotyping and next-generation sequencing techniques are discussed. Methods necessary for Sanger sequencing, multiplex ligation-dependent probe amplification, and epigenetic modification methods are detailed. In addition, protocols for cell culture establishment and characterization from patients with inherited dental anomalies are described.

Chronic Metabolic Derangement-Induced Cognitive Deficits and Neurotoxicity Are Associated with REST Inactivation.

Chronic metabolic alterations may represent a risk factor for the development of cognitive impairment, dementia, or neurodegenerative diseases. Hyperglycemia and obesity are known to imprint epigenetic markers that compromise the proper expression of cell survival genes. Here, we showed that chronic hyperglycemia (60 days) induced by a single intraperitoneal injection of streptozotocin compromised cognition by reducing hippocampal ERK signaling and by inducing neurotoxicity in rats. The mechanisms appear to be linked to reduced active DNA demethylation and diminished expression of the neuroprotective transcription factor REST. The impact of the relationship between adiposity and DNA hypermethylation on REST expression was also demonstrated in peripheral blood mononuclear cells in obese children with reduced levels of blood ascorbate. The reversible nature of epigenetic modifications and the cognitive impairment reported in obese children, adolescents, and adults suggest that the correction of the anthropometry and the peripheral metabolic alterations would protect brain homeostasis and reduce the risk of developing neurodegenerative diseases.

Resveratrol Reverts Epigenetic and Transcription Changes Caused by Smoke Inhalation on Bone-Related Genes in Rats.

We investigated the effects of cigarette smoke (CS) and resveratrol intake on the modulation of bone repair-related genes through epigenetic mechanisms at the global and gene-specific levels, after 30 days of calvarial defects were created, in rats. The samples were assigned to three groups as follows: no CS, CS, and CS/resveratrol. After evaluation of global (5 hmC) changes and epigenetic and transcription regulation at gene-specific levels, CS group showed increased 5 hmC and Tets transcripts with demethylation at Rankl and Trap promoters (p ≤ 0.01), linked to their increased gene expression (p ≤ 0.001). These modifications were reverted in the CS/resveratrol group. Opposite patterns were observed among CS and CS/resveratrol for epigenetic enzyme transcripts with higher levels of Dnmts in the CS/resveratrol (p ≤ 0.01). No CS and CS/resveratrol demonstrated similar gene expression levels for all Tets and bone-related genes. Resveratrol reverts epigenetic and transcription changes caused by CS at both global and gene-specific levels in bone-related and epigenetic machinery genes, emphasizing the resveratrol as biological modulator for CS in rats.

Association of SOCS1 (- 820) (rs33977706) gene polymorphism with chronic periodontitis: A case-control study in Brazilians.

It is evident that the accumulation of periodontal pathogens over the teeth surface triggers periodontitis; however, its aggravation and severity depend on other elements such as environmental factors, systemic health and the host genetic and/or epigenetic background. To address this issue, we investigated the association of two genetic polymorphisms placed on promoter region of SOCS1 gene with chronic periodontal disease. SOCS1 regulates Jak/Kinase signaling pathway and changes in its mRNA expression have been related to different types of cancer and chronic inflammation, including chronic periodontitis. The frequency of alleles and genotypes of two polymorphisms in SOCS1 gene promoter (position - 820 (rs33977706) and position - 1478 (rs33989964)) were analyzed by performing RFLP and TaqMan system in a total of 257 non-smoking subjects. We found a low frequency of A allele and A/A genotype of SOCS1(- 820) polymorphism in the chronic periodontitis group, especially when severe periodontitis samples were separately analyzed (OR = 0.3933; p = 0.0084 (IC95% 0.2112 < µ < 0.7324)), suggesting that A allele plays protective effect against chronic periodontitis. We did not find association between SOCS1-1478 polymorphism and periodontitis. In addition, analysis of SOCS1 (- 820/- 1478) haplotype revealed that the frequency of A(- 820)/CA(- 1478) haplotype decreases in ChrP (p = 0.0089). In conclusion, our study found that SOCS1(- 820) polymorphism is associated with chronic periodontitis.

Genetic analysis of the IL8 gene polymorphism (rs4073) in generalized aggressive periodontitis.

OBJECTIVES: Interleukin (IL)-8 is an important chemokine for regulation of the inflammatory response. A single nucleotide polymorphism (SNP) reference sequence (rs) 4073 in the IL8 gene has been shown to regulate IL-8 levels after stimulation with lipopolysaccharide. This study investigates the transmission pattern of the IL8 rs4073 risk allele A and its association with susceptibility to aggressive periodontitis (AgP) in families and in a case-control cohort of unrelated individuals from a Brazilian population. DESIGN: Genotyping was performed by standard polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP) in 13 nuclear families and 184 unrelated subjects. Statistical analysis was performed using the transmission disequilibrium test (TDT) for the family dataset and Chi-square test and multivariate logistic regression modelling for the case-control dataset. RESULTS: TDT analyses did not detect evidence of over transmission of IL8 rs4073 alleles in affected and unaffected family members (allele T: 52%; allele A: 48%; p=0.2252). How expected, analyses of cases and unrelated controls showed a significant and inverse association of age with AgP; however, a lack of association between genotypes, ethnic groups and generalized AgP was observed. CONCLUSIONS: The SNP (rs4073) was not associated with AgP in unrelated individuals and there is no evidence of over transmission of the alleles in families with AgP, from Brazilian individuals.

TLR2 and TLR4 gene promoter methylation status during chronic periodontitis.

AIM: The objective of this study was to analyse the status of DNA methylation in the promoter region of the toll-like receptor (TLR)2 and TLR4 genes in gingival tissue samples from healthy subjects, smokers and non-smokers affected by chronic periodontitis. MATERIAL AND METHODS: Genomic DNA and total RNA were purified from gingival tissue using the TRIZOL reagent protocol. Genomic DNA was then digested by methylation-sensitive restriction enzymes, amplified by polymerase chain reaction (PCR), electrophoresed on a 10% polyacrylamide gel and stained using SYBR Gold. Real-time PCR was also performed to verify the transcript levels. RESULTS: The CpG dinucleotides analysed were observed to be unmethylated in the majority of DNA samples of the three groups and statistical differences were not found among groups (p>0.05). However, a trend towards methylation was observed in the TLR2 HhaI site in the samples of the periodontitis non-smoker groups. In fact, the analysis of all CpG sites together shows which complete methylation is observed in the shortest level in the samples of periodontitis non-smoker group. The analysis of transcript levels demonstrated no difference among groups (p>0.05). CONCLUSION: The results demonstrated major unmethylation of the TLR4 gene promoter in all groups. However, the results for the TLR2 gene promoter are inconclusive; this gene was found as a mosaic of methylated and unmethylated DNA in the majority of samples of the three groups and we also observed a trend towards the DNA methylation of CpG sites recognized by the HhaI enzyme.

Biochemical evaluation of glycemic levels of long-term tacrolimus therapy in rats.

One of the more serious complications following transplantation is the development of post-transplantation diabetes mellitus (PTDM), which has a major impact on the quality of life, with effects ranging from the control of glycemia times to increased susceptibility to infections and cardiovascular complications. It has been suggested that immunosuppressive therapy, mainly tacrolimus therapy, may be an important factor in the development of PTDM. There is a lack of studies that explore the effects of long-term tacrolimus on PTDM in animal protocols. The objective of this study was therefore to evaluate the effects of long-term therapy with tacrolimus in rats. One group was treated with tacrolimus, injected subcutaneously, in a daily dose of 1 mg/kg of body weight. The chosen dose was sufficient to achieve therapeutic tacrolimus serum levels. The experimental periods were 60, 120, 180 and 240 days. One group was used as control and received daily subcutaneous injections of saline solution during all periods. A tendency towards increased glycemia levels during the initial periods (60 and 120 days) was observed. However, at 180 and 240 days, the glycemia levels were not statistically different from that of the control group of the same period. It may thus be concluded that the deleterious effects of tacrolimus therapy on glycemia may be a time-related side effect.

Microbiologic changes following administration of locally delivered doxycycline in smokers: a 15-month follow-up.

BACKGROUND: Additional clinical benefits have been reported with the use of locally delivered antimicrobials in the treatment of smokers; however, long-term changes in the subgingival microbiota following the use of these drugs in smokers have not been documented. The aim of this study was to evaluate long-term microbiologic changes following locally delivered doxycycline in the treatment of smokers. METHODS: Sixteen smokers with chronic periodontitis presenting a minimum of four pockets (probing depth>or=5 mm) were selected. Patients were assigned randomly to receive scaling and root planing (SRP) or SRP and local doxycycline (SRP-D). Patients were treated at baseline and 12 months. Subgingival plaque samples were collected at baseline; 3, 6, and 12 months; and 45 and 90 days following retreatment. Polymerase chain reaction and DNA-DNA hybridization analyses were performed to detect the presence of selected periodontal pathogens. RESULTS: The reduction in the number of sites positive for Porphyromonas gingivalis and Tannerella forsythia (previously T. forsythensis) was statistically significant for SRP-D at 3 months (68% and 41.3%, respectively) and for SRP at 6 months (75% and 52%, respectively) following treatment. The SRP group showed a greater frequency of P. gingivalis than the SRP-D group at 3 months (58% and 25%, respectively). There also was a greater reduction in the frequency of P. gingivalis at 3 months following retreatment with SRP-D compared to SRP (47% and 8%, respectively). CONCLUSION: In smokers, adjunctive local doxycycline resulted in a greater reduction in the frequency of P. gingivalis following initial and supportive therapy compared to conventional treatment.

Clinical attachment level measurements with and without the use of a stent by a computerized electronic probe.

OBJECTIVE: The aim of the present study was to evaluate whether a stent should be used when assessing attachment level (AL) by an electronic probe (Florida Probe). METHODS: Twenty patients were recruited and individual stents were obtained to measure relative AL (RAL) with the Florida stent probe. Conventional AL (CAL) measurements were obtained by adding pocket depth and gingival recession recorded by the Florida pocket probe. Duplicate RAL and CAL measurements were taken one hour apart from each other on anterior teeth, at six sites per tooth, by one examiner. Patients were treated and reassessed with both probes after 45 days so that the gain in RAL and CAL could also be compared. RESULTS: Pearson's correlation test showed that correlation was moderate (r = 0.57) and significant (p < 0.001) for duplicate CAL measurements. As for RAL values, correlation was higher (0.91) and significant (p < 0.001). The difference between RAL and CAL gain after 45 days was 0.04 mm (p = 0.85). CONCLUSION: Since the correlation was higher for duplicate RAL measurements than for CAL measurements, the use of a stent should be considered in clinical trials to ensure better reproducibility of measurement of attachment level gains.

Biochemical evaluation of glycemic levels of long-term tacrolimus therapy in rats

One of the more serious complications following transplantation is the development of post-transplantation diabetes mellitus (PTDM), which has a major impact on the quality of life, with effects ranging from the control of glycemia times to increased susceptibility to infections and cardiovascular complications. It has been suggested that immunosuppressive therapy, mainly tacrolimus therapy, may be an important factor in the development of PTDM. There is a lack of studies that explore the effects of long-term tacrolimus on PTDM in animal protocols. The objective of this study was therefore to evaluate the effects of long-term therapy with tacrolimus in rats. One group was treated with tacrolimus, injected subcutaneously, in a daily dose of 1 mg/kg of body weight. The chosen dose was sufficient to achieve therapeutic tacrolimus serum levels. The experimental periods were 60, 120, 180 and 240 days. One group was used as control and received daily subcutaneous injections of saline solution during all periods. A tendency towards increased glycemia levels during the initial periods (60 and 120 days) was observed. However, at 180 and 240 days, the glycemia levels were not statistically different from that of the control group of the same period. It may thus be concluded that the deleterious effects of tacrolimus therapy on glycemia may be a time-related side effect.

Uma das mais sérias complicações pós-transplante é o desenvolvimento de Diabetes Mellitus Pós-Transplante (DMPT), que irá produzir um grande impacto na qualidade de vida, com variações do controle glicêmico, aumentando a susceptibilidade a infecções e complicações cardiovasculares. Tem sido sugerido que a terapia imunossupressora, principalmente com tacrolimo, pode ser um importante fator no desenvolvimento de DMPT. Existem atualmente poucos estudos explorando os efeitos de um longo período de terapia com tacrolimo sobre DMPT em protocolos animais. Portanto, o objetivo deste estudo foi avaliar o efeito glicêmico de uma terapia por longo período com tacrolimo em ratos. Um grupo foi tratado com tacrolimo com doses diárias subcutâneas de 1 mg/kg de peso corporal. A escolha dessa dose foi suficiente para a obtenção dos níveis séricos terapêuticos desejados com tacrolimo. Os períodos experimentais foram 60, 120, 180 e 240 dias. Outro grupo foi usado como controle e recebeu injeções salinas subcutâneas diariamente durante todos os períodos. Houve uma tendência ao aumento do nível glicêmico nos períodos iniciais (60 e 120 dias). Entretanto, após 180 e 240 dias, os níveis de glicemia não foram estatisticamente diferentes dos obtidos nos grupos controles de mesmo período. Assim, pode-se concluir que os efeitos glicêmicos adversos provocados pela terapia com tacrolimo podem ser relacionados ao tempo.

Tecido ósseo: aspectos morfológicos e histofisiológicos / Bone issue: morphological and histophysiological aspects

O tecido ósseo tem papel importante no suporte, proteção e locomoção e está sob o controle de fatores sistêmicos, como os hormônios, e fatores locais, como os fatores de crescimentoe as citocinas. Portanto, os sistemas imune e esquelético encontram-se intimamente relacionados; aesta área interdisciplinar de estudos deu-se o nome de Osteoimunologia. A homeostase do sistema esquelético está na dependência de uma remodelação óssea equilibrada, ou seja, da dinâmicabalanceada entre a atividade dos osteoblastos, células de formação óssea, e osteoclastos, células de reabsorção óssea. Este balanço é firmemente controlado pelo sistema imune. Se este balanço inclinar-se a favor dos osteoclastos, levará a reabsorções patológicas, como nas periodontites,artrites reumatóides e doenças osteoporóticas. A compreensão deste processo, como um todo, podeser a chave para o desenvolvimento de um protocolo de tratamento que poderia levar ao equilíbrio dessas doenças ósseas. Sendo assim, nesta revisão da literatura, nós fornecemos uma visão do tecido ósseo: a composição química de sua matriz, células e componentes celulares, descrevendo como ocorre o processo de remodelação óssea e alguns fatores locais e sistêmicos que interferem neste processo, como citocinas e hormônios.

The bone tissue has an important role in the support, protection and locomotionand it is under control of systemic factors, such as hormones and local regulatory molecules, for instance, growth factor and cytokines. Therefore, the immune and skeletal systems are intimately related; this interdisciplinary branch has been referred as osteoimmunology. The homeostasis of the skeletal system depends directly on a balanced bone remodeling, i.e., the dynamic balance between the activities of the osteoblasts, bone forming cells and osteoclasts, bone resorbing cells.This balance is tightly and thoroughly controlled by some regulatory systems, such as the immune system. Tipping this balance towards the osteoclasts leads to pathological bone resorption, suchas periodontitis, autoimmune arthritis and osteoporotic diseases. The understanding this overallprocess may be the key to development of a treatment protocol, which could lead to the balance of these bone diseases. Thus, in this literature review, we provide an overview of the bone tissue composition, its cells and proteins of bone matrix, describing how the remodeling bone processoccurs, as well as some local and systemic factors that interfere in this process, such cytokines and hormones.

Locally delivered doxycycline as an adjunctive therapy to scaling and root planing in the treatment of smokers: a 2-year follow-up.

BACKGROUND: The aim of this clinical study was to evaluate the association of locally delivered doxycycline 10% with scaling and root planing in the periodontal treatment of smokers during a 2-year period. METHODS: Forty-eight chronic periodontitis patients, presenting a minimum of four pockets (>or=5 mm) that bled on probing on anterior teeth were included. Patients were randomly assigned to receive one of the following treatments: scaling and root planing (SRP) and scaling and root planing followed by local application of doxycycline (SRP-D). Assigned treatments were performed at baseline and at 12 months. Clinical parameters, including probing depth (PD) and relative attachment level (RAL), were recorded at baseline; 45 days; 3, 6, and 12 months (retreatment); 45 days following retreatment; and at 15, 18, and 24 months. RESULTS: In initially deep pockets (>or=7 mm), SRP-D showed greater PD reduction than SRP at 6 and 18 months (mean difference between groups of 1.18 and 1.73 mm, respectively; P <0.05) and greater RAL gain in all periods after 3 months (mean difference between groups of 1.16, 1.99, and 1.78 mm, at 6, 18, and 24 months, respectively; P <0.05). Also, the proportion of sites showing >or=2 mm PD reduction was greater for SRP-D at 6 months (81.2% x 50.8%; P <0.001) and at 24 months (65.5% x 46.5%; P = 0.01). As for RAL gain, this proportion was 34.4% and 18.1% for SRP-D and SRP at 24 months, respectively (P = 0.008). CONCLUSION: The use of locally delivered doxycycline may constitute an important adjunct for the active and supportive treatments of severe periodontal disease in smokers.

Reproducibility of clinical attachment level and probing depth of a manual probe and a computerized electronic probe.

The aim of this study was to evaluate the reproducibility of a conventional manual probe (MP) and an electronic probe, the Florida Probe (FP). Twenty patients with chronic periodontitis were assessed for pocket depth (PD) and clinical attachment level (CAL) by one examiner. Replicate measurements were taken one hour apart with each probe, on anterior teeth, at six sites per tooth. Pearson's correlation test and Student's paired t-test were used for the statistical analysis. The results showed that there were no significant differences in PD between the replicate measurements of both FP and MP (p > 0.05), although the correlation value was higher for FP (r = 0.97, p < 0.01) than for MP (r = 0.54, p < 0.05). Considering CAL, no differences were found between replicate measurements for both FP and MP (p > 0.05) and correlation values were similar (0.57 and 0.64, respectively, p < 0.001). Although the FP showed higher correlation values for PD, no significant differences were found between duplicate measurements for both probes. Thus, both electronic and manual probing measurements seem to be reproducible when assessing periodontal disease.

Smoking may affect root coverage outcome: a prospective clinical study in humans.

BACKGROUND: Cigarette smoking has been shown to negatively influence healing following periodontal therapeutic procedures. Therefore, the aim of this study was to evaluate the impact of smoking on clinical outcome of root coverage following subepithelial connective tissue graft (CTG) surgery. METHODS: Eighteen defects were treated in 15 patients (seven smokers and eight non-smokers) who presented canine and pre-molar Miller Class I and II recessions. CTG was performed and clinical measurements were obtained at baseline, and 30, 60, 90, and 120 days after surgery. Clinical measurements included plaque and gingival indexes, gingival recession, probing depth, clinical attachment level, gingival thickness, and keratinized tissue width. RESULTS: Intragroup analysis showed that CTG was able to promote root coverage, increase gingival thickness, and improve clinical attachment level in both groups (P < 0.05). On the other hand, intergroup analysis demonstrated that smokers presented with a lower percentage of root coverage (58.84% +/- 13.68% versus 74.73% +/- 14.72%), less clinical attachment level gain (2.54 +/- 0.79 mm versus 2.00 +/- 1.04 mm), and deeper probing depths (1.56 +/- 0.53 mm versus 2.35 +/- 0.67 mm) than non-smokers (P < 0.05). Moreover, 4 months after CTG, smokers presented more keratinized tissue compared to non-smokers (3.30 +/- 0.86 mm versus 4.50 +/- 1.16 mm) (P < 0.05). CONCLUSION: Within the limits of the present study, it can be concluded that cigarette consumption may present a negative impact on root coverage outcome by CTG and, therefore, may represent one more challenge for periodontal plastic therapy.