Two-step periosteal releasing incision for tension-free flap closure after implant placement with simultaneous guided bone regeneration

We evaluated the effect of periosteal-releasing incisions on flap displacement in anterior maxillary sites following implant placement and simultaneously guided bone regeneration. Thirty patients requiring a single dental implant and guided bone regeneration in the maxillary esthetic zone were recruited. After full-thickness flap elevation, the displacement of the flap was measured under a standardized tension of 1 Ncm. Then, a two-step periosteal releasing incision was placed in the internal aspect of the flap, and the displacement was remeasured using the same standardized tension. Keratinized tissue width and mucosal thickness at the surgical site were recorded. Patient-reported outcomes were assessed at the 7- and 14-day recall visits. Flap displacement (primary outcome) was calculated before and after periosteal-releasing incisions. Multivariable linear regression models were used to evaluate the influence of mucosal thickness on flap displacement and adjusted for Keratinized tissue width. Primary wound closure was achieved in all patients. The mean difference in flap coronal displacement before and after the periosteal-releasing incisions was 8.2 mm (p<0.0001). Adjusted regression models showed no association between mucosal thickness and keratinized tissue width with the amount of flap displacement (p=0.770). PROMs for pain, swelling, and bleeding amounted to 1.28 ± 1.93, 1.36 ± 1.87, and 0.0 ± 0.0 at seven days and 0.11 ± 0.57, 0.56 ± 1.03, and 0.0 ± 0.0 at 14 days, respectively. Periosteal-releasing incisions using the two-step procedure described here are a predictable technique to obtain coronal flap displacements > 8 mm without increased surgical complications.

Topological insight of immune-vascular distribution in peri-implantitis lesions

OBJECTIVE

To characterize the distribution of macrophages, neutrophils, NK cells, and blood vessels in peri-implantitis compared to healthy aged gingiva samples.

MATERIALS AND METHODS

This observational study included eight gingival samples from peri-implantitis and eight from periodontally healthy individuals. By immunofluorescence were identified neutrophils, NK cells, macrophages, and their pro-inflammatory or pro-healing phenotypes, and blood vessels. Two ROIs were designated as zone 1, connective tissue closest to the epithelium and zone 2, connective tissue over 200 microns from the rete ridges. Immune cells and vascular structures were quantified and characterized according to their distribution in both zones.

RESULTS

Two peri-implantitis zones were characterized by unique macrophage phenotypes and blood vessel architecture. Blood vessels were larger in zone 2 in peri-implantitis. A greater number of NK cells and macrophages were found in peri-implantitis compared to healthy aged samples. A higher presence of pro-inflammatory macrophages was found in zone 1 compared to zone 2. A similar proportion of pro-inflammatory and pro-healing macrophages were found in zone 2.

CONCLUSION

A specific distribution for pro-inflammatory macrophages and vascular architecture is observed in peri-implantitis. TNF-α colocalizes with macrophages in the connective tissue near rete ridges. NK cells are more abundant in peri-implantitis than in healthy samples.

Pilot Study: Periosteal Mattress Sutures as an Alternative to Pins and Screws in Guided Bone Regeneration in the Esthetic Zone

OBJECTIVES

To quantify the buccal bone thickness, area, and perimeter following guided bone regeneration (GBR) using stabilizing periosteal sutures. The loss in hard tissue volume may impair proper implant placement. GBR has been used to regenerate the lost alveolar ridge prior to or at the same time as dental implant placement. The most important factor for GBR success is graft stability. The periosteal mattress suture (PMS) stabilizing technique is an alternative to pins and screws to stabilize bone grafting material and has the advantage of not requiring the removal of the fixing devices.

MATERIALS AND METHODS

A CBCT was acquired before and 6 months after surgery from six patients who underwent GBR with the PMS stabilizing technique. Images were analyzed for buccal bone thickness, area, and perimeter.

RESULTS

The mean change in buccal bone thickness was 3.42 mm (± 1.31 SD) and proved statistically significant (P = .005). The mean change in bone crest area also proved statistically significant (P = .001). No significant difference was found in bone perimeter (P = .12).

CONCLUSIONS

The PMS technique delivered optimal results without clinical complications. This study shows the potential of this technique as an alternative to pins or screws for graft stabilization in the esthetic zone.

Epidemiology of mid-buccal gingival recessions according to the 2018 Classification System in South America: Results from two population-based studies

AIM

The aim of this investigation was to estimate the prevalence, severity and extent of mid-buccal gingival recessions (GRs; classified according to the 2018 Classification System) and to identify their risk indicators in the South American population.

MATERIALS AND METHODS

Epidemiological data from two cross-sectional studies-performed on 1070 South American adolescents and 1456 Chilean adults-were obtained. All participants received a full-mouth periodontal examination by calibrated examiners. GR prevalence was defined as the presence of at least one mid-buccal GR ≥ 1 mm. GRs were also categorized into different recession types (RTs) according to the 2018 World Workshop Classification System. Analyses for RT risk indicators were also performed. All analyses were carried out at the participant level.

RESULTS

The prevalence of mid-buccal GRs was 14.1% in South American adolescents and 90.9% in Chilean adults. In South American adolescents, the prevalence of RTs was 4.3% for RT1 GRs, 10.7% for RT2 GRs and 1.7% for RT3 GRs. In Chilean adults, the prevalence of RT1 GRs was 0.3%, while the prevalence of RT2 and RT3 GRs was 85.8% and 77.4%, respectively. Full-Mouth Bleeding Score (FMBS; <25%) was associated with the presence of RT1 GRs in adolescents. The risk indicators for RT2/RT3 GRs mainly overlapped with those for periodontitis.

CONCLUSIONS

Mid-buccal GRs affected 14.1% of South American adolescents, whereas they affected most of the Chilean adult population (>90%). While RT1 GRs are more commonly observed in a non-representative cohort of South American adolescents (when compared to Chilean adults), the majority of Chilean adults exhibit RT2/RT3 GRs.

Transcatheter aortic valve implantation (TAVI) with zero contrast in patients with impairment of renal function. A single centre experience

 

Transcatheter aortic valve implantation (TAVI) represents nowaday a safe and effective alternative to traditional surgery for patients with high and intermediate surgical risk. However, the risk of contrast induced nephropathy still remains a major concern and a real challenge in patients with baseline chronic kidney disease (CKD). Aim of our new approach, has been to find a solution capable to reduce or contain the incidence of acute renal damage after TAVI caused by the use of contrast dye in CKD patients.

In the last twelve months, out of 85 patients admitted to our Center for severe symptomatic aortic stenosis, addressed to TAVI, 18 patients (mean age: 81.8 years, NYHA class III) presented CKD with mean creatinine value: 2.39 mg/dl; GFR: 24.46 ml/min/1.73 m2. Three patients had previously undergone surgical revascularization with coronary artery bypass graft and in 3 cases we performed a valve-in-valve procedure for degeneration of valvular bioprostheses.They were selected for our zero contrast protocol; all these patients underwent pre-procedural chest and abdomen CT scan without dye, together with a Lower Limb Eco-Color Doppler scan.Coronary angiography had been carried out in a previous hospitalization.

The valve size choice was determined after measurements of the CT scan and echo images (both two- and three-dimensions) were compared. Data obtained (valve perimeter, area and the two main valve diameters) were strongly similar with the two techniques, without significant differences. The new valve deployment was monitored under constant fluoroscopy and transesophageal (TOE) visualization. A single pig tail catheter was placed in the non coronary sinus to facilitate valve annulus localization on fluoroscopy. The TOE selected view for TAVI deployment was the mid esophageal long axis. Proper prosthesis positioning was determined by measuring the protruding portion through the left ventricle outflow tract, and prevent possible impairment of diastolic mitral valve movement. In 17 cases a transfemoral percutaneous approach was used and only in one case surgical isolation of the right carotid artery was necessary due to the occlusion of every other peripheral access. Four patients needed a post implant dilatation for significant residual left ventricle/aortic gradient. All patients underwent the TAVI procedure successfully. In the post-TAVI phase, two patients underwent definitive PM implantation for third degree atrioventricular block despite adequately high implantation of the valve.At discharge, mean creatinine value was 1.9 mg/dl and mean GFR was 32.2 ml/min/1.73 m2. All patients survived the procedure and were discharged alive, after a further mean Hospital stay of four days. In conclusion, TAVI zero contrast is a safe, feasible and winning procedure to consider in patients with severely impaired renal function.

Funding Acknowledgement

Type of funding sources: None.

Impact of COVID-19 Pandemic on Quality of Life of Type II Diabetes Patients With Periodontitis

Background: Confinement due to the COVID-19 pandemic has made dental treatments impossible in Chile and many other countries, including diabetic patients with periodontitis. The aim of the present study was to evaluate the impact of periodontal therapy in terms of oral health-related quality of life (OHRQoL) during the COVID-19 pandemic in a cohort of diabetic patients with periodontitis. Material and Methods: Thirty-eight diabetic patients with stage III-IV periodontitis, enrolled for periodontal therapy, were screened. Periodontal clinical parameters including clinical attachment loss (CAL), probing pocket depth (PPD) and bleeding on probing (BOP) as well as glycated hemoglobin (HbA1c) were evaluated at baseline and 3 months follow-up prior the pandemic. The OHRQoL changes by means of Oral Health Impact Profile (OHIP-14) and a self-reported oral health questionnaire were assessed at baseline (prior pandemic) and during the pandemic via telemonitoring. Results: Thirty-one patients received non-surgical periodontal therapy prior to the pandemic. Out of the 31 patients, four died due to COVID-19 resulting in 27 patients available for telemonitoring at the time of the pandemic. Periodontal therapy significantly improved CAL, PPD and BOP (p < 0.05) but not HbA1c (p > 0.05) between baseline and 3 months follow-up pior to the pandemic. Total OHIP-14 scores significantly improved between baseline and the middle of pandemic (intragroup comparison p = 0.00411). In particular, OHIP-14 scores related to the "Physical pain" (intragroup comparison p = 0.04) and "Psychological disability" (intragroup comparison p = 0.00) significantly improved between baseline and the middle of pandemic. Conclusions: In diabetic type II patients with periodontitis periodontal therapy tends to improve the oral health-related quality of life despite the COVID-19 pandemic.

Performance of the 2017 AAP/EFP case definition compared to the CDC/AAP definition in population-based studies

BACKGROUND

Classification of the periodontal conditions is indispensable for epidemiological data in order to guide situational awareness and therapeutic strategies. The new classification of periodontal diseases and conditions introduced by the American Academy of Periodontology and the European Federation of Periodontology (AAP/EFP), however, has not yet been applied to population-based studies. The aim of the present study was to compare the prevalence of periodontitis between the AAP/EFP and the CDC/AAP classification system and to evaluate the accuracy of the new AAP/EFP classification system against the CDC/AAP case definition for population-based studies.

METHODS

Epidemiological data from two cross-sectional studies were obtained. One of them was a population-based study on Chilean adults (1.456 individuals; 35-44 years; 65-74 years) and the other one a sample of adolescents (1.070 individuals; 15-19 years) from 5 countries; Argentina, Chile, Colombia, Ecuador and Uruguay. All participants had undergone full-mouth periodontal examination by calibrated examiners. Epidemiological datasets were analyzed according to the AAP/EFP and the CDC/AAP case definitions. The accuracy of the AAP/EFP definition was examined by assessing the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the receiver operating curve (ROC) using the CDC/AAP case definition as the reference standard.

RESULTS

According to the AAP/EFP, the prevalence of periodontitis in adolescents was 75.6%. The majority of the adolescents were classified either as stage I (39.2%) or stage II (28.2%). By using the CDC/AAP classification the prevalence of periodontitis in adolescents was 27.2%. The most common form of periodontitis with the CDC/AAP classification was moderate periodontitis (15.3%) followed by mild periodontitis (11.4%). The AAP/EFP revealed high sensitivity in moderate (95.7%) and severe periodontitis (100%) as well as a moderate (75%) to high specificity (92%) in moderate and severe periodontitis, respectively. The PPV was 41.6% in moderate and 5.7% in severe periodontitis while the NPV was high in both categories (moderate = 99%; severe = 100%). The AUC was 0.912 (95% CI = 0.89 - 0.93). In adults, the prevalence of periodontitis was 99% according to the AAP/EFP. The majority of adults were classified as stage IV (81.3%) whereas stage III amounted to 12.8%. By using the CDC/AAP classification, the prevalence of periodontitis in adults was 88.3% and the most common form of periodontitis was moderate periodontitis (57.2%) followed by severe periodontitis (29.7%). In adults, the AAP/EFP revealed high sensitivity in moderate (99.7%) and severe periodontitis (100%) but low specificity in both categories (moderate = 6.8%; severe = 8.3%). The PPV was 88.7% in moderate and 31.7% in severe periodontitis. The NPV was high in both categories (moderate = 76.5%; severe = 100%). The AUC was 0.573 (95% CI = 0.53 - 0.62).

CONCLUSIONS

This study revealed a clear discrepancy in the prevalence of periodontitis between the AAP/EFP and the CDC/AAP classification when using epidemiological data. The 2017 AAP/EFP classification system performs well compared to the CDC/AAP case definition in identifying adolescents with periodontitis. The AAP/EFP system seems less accurate in adults with high prevalence of periodontitis. This article is protected by copyright. All rights reserved.

Periodontal Treatment Protocol for Decompensated Diabetes Patients

Background: Decompensated diabetes is associated with a higher prevalence and severity of periodontitis and poorer response to periodontal therapy. It is conceivable that periodontal therapy may cause systemic and local complications in this type of patients. The aim of the present study was to identify and describe the best available evidence for the treatment of periodontitis in decompensated diabetics.

Material and methods: An expert committee including participants from different areas gathered to discuss and develop a treatment guideline under the guidance of the Cochrane Associate Center, Faculty of Dentistry, University of Chile. In total, four research questions were prepared. The questions prepared related to decompensated diabetic patients (glycated hemoglobin >8) were, (1) Does the exposure to periodontal treatment increase the risk of infectious or systemic complications? (2) Does the antibiotic treatment or prophylaxis, compared to not giving it, reduce infectious complications? (3) Does the exposure to periodontal treatment, compared to no treatment, reduce the glycated hemoglobin levels (HbA1c)? Last question was related to diabetic patients, (4) Does the exposure to a higher level of HbA1c, compared to stable levels, increase the risk of infectious complications? Based on these questions, a search strategy was developed using MEDLINE and EPISTEMONIKOS. Only systematic reviews were considered.

Results: For question 1, the search yielded 12 records in EPISTEMONIKOS and 23 in MEDLINE. None of these studies addressed the question. For question 2, the search yielded 58 records in EPISTEMONIKOS and 11 in MEDLINE. None of these studies addressed the question. For question 3, the search yielded 16 records in EPISTEMONIKOS and 11 in MEDLINE. Thirteen addressed the question. For question 4, the search yielded 7 records in EPISTEMONIKOS and 9 in MEDLINE. One addressed the question.

Conclusions: In decompensated diabetic patients, there is lack of scientific information about risk of infectious or systemic complications as a result of periodontal treatment and about the impact of antibiotic treatment or prophylaxis on reduction if infectious complications. A defined HbA1c threshold for dental and periodontal treatment in diabetic patients has yet to be determined. Finally, periodontal treatment does have an impact on HbA1c levels.

Determinants of Periodontal/Periapical Lesion Stability and Progression

Periodontal and periapical lesions are infectious inflammatory osteolitytic conditions in which a complex inflammatory immune response mediates bone destruction. However, the uncertainty of a lesion's progressive or stable phenotype complicates understanding of the cellular and molecular mechanisms triggering lesion activity. Evidence from clinical and preclinical studies of both periodontal and periapical lesions points to a high receptor activator of NF-κB ligand/osteoprotegerin (RANKL/OPG) ratio as the primary determinant of osteolytic activity, while a low RANKL/OPG ratio is often observed in inactive lesions. Proinflammatory cytokines directly modulate RANKL/OPG expression and consequently drive lesion progression, along with pro-osteoclastogenic support provided by Th1, Th17, and B cells. Conversely, the cooperative action between Th2 and Tregs subsets creates an anti-inflammatory and proreparative milieu associated with lesion stability. Interestingly, the trigger for lesion status switch from active to inactive can originate from an unanticipated RANKL immunoregulatory feedback, involving the induction of Tregs and a host response outcome with immunological tolerance features. In this context, dendritic cells (DCs) appear as potential determinants of host response switch, since RANKL imprint a tolerogenic phenotype in DCs, described to be involved in both Tregs and immunological tolerance generation. The tolerance state systemically and locally suppresses the development of exacerbated and pathogenic responses and contributes to lesions stability. However, immunological tolerance break by comorbidities or dysbiosis could explain lesions relapse toward activity. Therefore, this article will provide a critical review of the current knowledge concerning periodontal and periapical lesions activity and the underlying molecular mechanisms associated with the host response. Further studies are required to unravel the role of immunological responsiveness or tolerance in the determination of lesion status, as well as the potential cooperative and/or inhibitory interplay among effector cells and their impact on RANKL/OPG balance and lesion outcome.

Periodontal disease and its impact on general health in Latin America. Section I: Introduction part I

A high level of general and oral health are invaluable assets, a factor not always considered a basic human right for their better life quality. The mouth is a critical point of contact with the external environment, which is established when we talk, chew, swallow and when food digestion begins. From a perspective of the human condition, the mouth is crucial for the integration of sound, social appearance of the individual, and is one of the fundamental components of overall health. Therefore, not having an adequate level of oral health affects self-esteem, quality of life and people's general well-being.

Effect of periodontal treatment in patients with periodontitis and diabetes: systematic review and meta-analysis

The evidence is inconclusive regarding the effect of periodontal treatment on glycemic control and systemic inflammation in patients with type 2 diabetes (T2D) and periodontitis

WNT gene polymorphisms and predisposition to apical periodontitis

Single nucleotide polymorphisms (SNPs) in WNT genes may impact gene/protein function and contribute to individual predisposition to apical periodontitis (AP). Here, we investigated the association of SNPs in/nearby WNT3, WNT3A, WNT5A, WNT8A, WNT9B and WNT11 genes with AP using a case-control dataset. Cases were defined as individuals with deep caries and AP (n = 188); controls had deep caries and no AP (n = 230). Genotyping was performed using Taqman chemistry in real time PCR. Data analyses was performed using Fisher Exact tests assuming a Bonferroni correction threshold value of 0.005. Single-SNP association analysis revealed a trend for association with WNT3 rs9890413 genotypes (P = 0.009) under a dominant model and allelic association for WNT3A rs1745420 (P = 0.009). Haplotypes involving WNT3-WNT9B-WNT3A alleles were also significantly associated with AP (P ≤ 0.003). Luciferase reporter assays showed higher transcriptional activity (1.4-fold) with the alternate G allele in rs1745420. Expression of WNT3, WNT3A and WNT5A in AP tissues was significantly higher than in control tissues, and inversely correlated with the expression of SERPINB1, COL1A1 and TIMP1 (P < 0.05). Our results suggest that WNT genes have a role in modulating AP and polymorphisms in these genes may increase susceptibility to AP.

Osteoimmunology of Oral and Maxillofacial Diseases: Translational Applications Based on Biological Mechanisms

The maxillofacial skeleton is highly dynamic and requires a constant equilibrium between the bone resorption and bone formation. The field of osteoimmunology explores the interactions between bone metabolism and the immune response, providing a context to study the complex cellular and molecular networks involved in oro-maxillofacial osteolytic diseases. In this review, we present a framework for understanding the potential mechanisms underlying the immuno-pathobiology in etiologically-diverse diseases that affect the oral and maxillofacial region and share bone destruction as their common clinical outcome. These otherwise different pathologies share similar inflammatory pathways mediated by central cellular players, such as macrophages, T and B cells, that promote the differentiation and activation of osteoclasts, ineffective or insufficient bone apposition by osteoblasts, and the continuous production of osteoclastogenic signals by immune and local stromal cells. We also present the potential translational applications of this knowledge based on the biological mechanisms involved in the inflammation-induced bone destruction. Such applications can be the development of immune-based therapies that promote bone healing/regeneration, the identification of host-derived inflammatory/collagenolytic biomarkers as diagnostics tools, the assessment of links between oral and systemic diseases; and the characterization of genetic polymorphisms in immune or bone-related genes that will help diagnosis of susceptible individuals.

HGMB1 and RAGE as Essential Components of Ti Osseointegration Process in Mice

The release of the prototypic DAMP High Mobility Group Box 1 (HMGB1) into extracellular environment and its binding to the Receptor for Advanced Glycation End Products (RAGE) has been described to trigger sterile inflammation and regulate healing outcome. However, their role on host response to Ti-based biomaterials and in the subsequent osseointegration remains unexplored. In this study, HMGB1 and RAGE inhibition in the Ti-mediated osseointegration were investigated in C57Bl/6 mice. C57Bl/6 mice received a Ti-device implantation (Ti-screw in the edentulous alveolar crest and a Ti-disc in the subcutaneous tissue) and were evaluated by microscopic (microCT [bone] and histology [bone and subcutaneous]) and molecular methods (ELISA, PCR array) during 3, 7, 14, and 21 days. Mice were divided into 4 groups: Control (no treatment); GZA (IP injection of Glycyrrhizic Acid for HMGB1 inhibition, 4 mg/Kg/day); RAP (IP injection of RAGE Antagonistic Peptide, 4 mg/Kg/day), and vehicle controls (1.5% DMSO solution for GZA and 0.9% saline solution for RAP); treatments were given at all experimental time points, starting 1 day before surgeries. HMGB1 was detected in the Ti-implantation sites, adsorbed to the screws/discs. In Control and vehicle groups, osseointegration was characterized by a slight inflammatory response at early time points, followed by a gradual bone apposition and matrix maturation at late time points. The inhibition of HMGB1 or RAGE impaired the osseointegration, affecting the dynamics of mineralized and organic bone matrix, and resulting in a foreign body reaction, with persistence of macrophages, necrotic bone, and foreign body giant cells until later time points. While Control samples were characterized by a balance between M1 and M2-type response in bone and subcutaneous sites of implantation, and also MSC markers, the inhibition of HMGB1 or RAGE caused a higher expression M1 markers and pro-inflammatory cytokines, as well chemokines and receptors for macrophage migration until later time points. In conclusion, HMGB1 and RAGE have a marked role in the osseointegration, evidenced by their influence on host inflammatory immune response, which includes macrophages migration and M1/M2 response, MSC markers expression, which collectively modulate bone matrix deposition and osseointegration outcome.

TBX21-1993T/C polymorphism association with Th1 and Th17 response at periapex and with periapical lesions development risk

TBX21-1993T/C (rs4794067) polymorphism increases the transcriptional activity of the Tbx21, essential for interferon gamma (IFNg) transcription, but its functional impact on development Th1- response in vivo remains unclear, as well its potential influence over inflammatory osteolytic conditions, such as periapical lesions. Therefore, this study comprises a case-control and functional investigation of Tbx21 genetic variations impact on Th1 response in vivo and in vitro, and its impact on periapical lesions risk and outcome, performed with a population of healthy controls (H; N = 283) and patients presenting periapical lesions (L; N = 188) or deep caries (DC; N = 152). TBX21-1993T/C genotyping demonstrated that the polymorphic allele C, as well TC/TC+CC genotypes, was significantly less frequent in the L patients compared to H and DC groups. Additionally, gene expression analysis demonstrates that T-cell-specific T-box transcription factor (Tbet) and IFNg transcripts levels were downregulated whereas IL-17 levels were upregulated in the TBX21-1993 C carriers (TC/TC+CC) in comparison with the TT group. Also, while TT and TC+CC genotypes are equally prevalent in the lesions presenting low IFN/IL17 ratio, a significant decrease in polymorphic TC+CC genotypes was observed in lesions presenting intermediate and high IFN/IL17 ratio. In vitro experiments confirmed the predisposition to Th1 polarization associated with TBX21-1993, since PBMC CD4 T cells from T allele carriers produce higher IFNg levels upon CD3/CD28 stimulation than the C group, in both standard/neutral and Th1-polarizing culture conditions. In conclusion, the TBX21-1993 T allele and TC/CC genotypes predispose to Th1-type immune response development in vitro, influence immune response polarization in vivo, and consequently account for the risk for apical periodontitis development.

CCR2 Contributes to F4/80+ Cells Migration Along Intramembranous Bone Healing in Maxilla, but Its Deficiency Does Not Critically Affect the Healing Outcome

Bone healing depends of a transient inflammatory response, involving selective migration of leukocytes under the control of chemokine system. CCR2 has been regarded as an essential receptor for macrophage recruitment to inflammation and healing sites, but its role in the intramembranous bone healing on craniofacial region remains unknown. Therefore, we investigated the role of CCR2 on F4/80+ cells migration and its consequences to the intramembranous healing outcome. C57BL/6 wild-type (WT) and CCR2KO mice were subjected to upper right incisor extraction, followed by micro-computed tomography, histological, immunological, and molecular analysis along experimental periods. CCR2 was associated with F4/80+ cells influx to the intramembranous bone healing in WT mice, and CCR2+ cells presented a kinetics similar to F4/80+ and CCR5+ cells. By contrast, F4/80+ and CCR5+ cells were significantly reduced in CCR2KO mice. The absence of CCR2 did not cause major microscopic changes in healing parameters, while molecular analysis demonstrated differential genes expression of several molecules between CCR2KO and WT mice. The mRNA expression of TGFB1, RUNX2, and mesenchymal stem cells markers (CXCL12, CD106, OCT4, NANOG, and CD146) was decreased in CCR2KO mice, while IL6, CXCR1, RANKL, and ECM markers (MMP1, 2, 9, and Col1a2) were significantly increased in different periods. Finally, immunofluorescence and FACS revealed that F4/80+ cells are positive for both CCR2 and CCR5, suggesting that CCR5 may account for the remaining migration of the F4/80+ cells in CCR2KO mice. In summary, these results indicate that CCR2+ cells play a primary role in F4/80+ cells migration along healing in intramembranous bones, but its deficiency does not critically impact healing outcome.

Oral implant osseointegration model in C57Bl/6 mice: microtomographic, histological, histomorphometric and molecular characterization

Despite the successful clinical application of titanium (Ti) as a biomaterial, the exact cellular and molecular mechanisms responsible for Ti osseointegration remains unclear, especially because of the limited methodological tools available in this field.

Bioactive glass-ceramic bone repair associated or not with autogenous bone: a study of organic bone matrix organization in a rabbit critical-sized calvarial model

OBJECTIVE

The aim of the study was to analyze bone matrix (BMX) organization after bone grafting and repair using a new bioactive glass-ceramic (Biosilicate^®) associated or not with particulate autogenous bone graft.

MATERIAL AND METHODS

Thirty rabbits underwent surgical bilateral parietal defects and divided into groups according to the materials used: (C) control-blood clot, (BG) particulate autogenous bone, (BS) bioactive glass-ceramic, and BG + BS. After 7, 14, and 30 days post-surgery, a fragment of each specimen was fixed in - 80 °C liquid nitrogen for zymographic evaluation, while the remaining was fixed in 10% formalin for histological birefringence analysis.

RESULTS

The results of this study demonstrated that matrix organization in experimental groups was significantly improved compared to C considering collagenous organization. Zymographic analysis revealed pro-MMP-2, pro-MMP-9, and active (a)-MMP-2 in all groups, showing gradual decrease of total gelatinolytic activity during the periods. At day 7, BG presented more prominent gelatinolytic activity for pro-MMP-2 and 9 and a-MMP-2, when compared to the other groups. In addition, at day 7, a 53% activation ratio (active form/[active form + latent form]) was evident in C group, 33% in BS group, and 31% in BG group.

CONCLUSION

In general, BS allowed the production of a BMX similar to BG, with organized collagen deposition and MMP-2 and MMP-9 disponibility, permitting satisfactory bone remodeling at the late period.

CLINICAL RELEVANCE

The evaluation of new bone substitute, with favorable biological properties, opens the possibility for its use as a viable and efficient alternative to autologous bone graft.

Colorectal Cancer-Associated Genes Are Associated with Tooth Agenesis and May Have a Role in Tooth Development

Previously reported co-occurrence of colorectal cancer (CRC) and tooth agenesis (TA) and the overlap in disease-associated gene variants suggest involvement of similar molecular pathways. Here, we took an unbiased approach and tested genome-wide significant CRC-associated variants for association with isolated TA. Thirty single nucleotide variants (SNVs) in CRC-predisposing genes/loci were genotyped in a discovery dataset composed of 440 individuals with and without isolated TA. Genome-wide significant associations were found between TA and ATF1 rs11169552 (P = 4.36 × 10-10) and DUSP10 rs6687758 (P = 1.25 × 10-9), and positive association found with CASC8 rs10505477 (P = 8.2 × 10-5). Additional CRC marker haplotypes were also significantly associated with TA. Genotyping an independent dataset consisting of 52 cases with TA and 427 controls confirmed the association with CASC8. Atf1 and Dusp10 expression was detected in the mouse developing teeth from early bud stages to the formation of the complete tooth, suggesting a potential role for these genes and their encoded proteins in tooth development. While their individual contributions in tooth development remain to be elucidated, these genes may be considered candidates to be tested in additional populations.

MMP1-1607 polymorphism increases the risk for periapical lesion development through the upregulation MMP-1 expression in association with pro-inflammatory milieu elements

Increased matrix metalloproteinases (MMPs) activity is a hallmark of periapical granulomas. However, the factors underlying the MMPs expression modulation in healthy and diseased periapical tissues remains to be determined.

TBX21-1993T/C (rs4794067) polymorphism is associated with increased risk of chronic periodontitis and increased T-bet expression in periodontal lesions, but does not significantly impact the IFN-g transcriptional level or the pattern of periodontophatic bacterial infection

Th1-polarized host response, mediated by IFN-γ, has been associated with increased severity of periodontal disease as well as control of periodontal infection. The functional polymorphism TBX21-1993T/C (rs4794067) increases the transcriptional activity of the TBX21 gene (essential for Th1 polarization) resulting in a predisposition to a Th-1 biased immune response. Thus, we conducted a case-control study, including a population of healthy controls (H, n = 218), chronic periodontitis (CP, n = 197), and chronic gingivitis patients (CG, n = 193), to investigate if genetic variations in TBX21 could impact the development of Th1 responses, and consequently influence the pattern of bacterial infection and periodontitis outcome. We observed that the polymorphic allele T was significantly enriched in the CP patients compared to CG subjects, while the H controls demonstrated and intermediate genotype. Also, investigating the putative functionality TBX21-1993T/C in the modulation of local response, we observed that the transcripts levels of T-bet, but not of IFN-γ, were upregulated in homozygote and heterozygote polymorphic subjects. In addition, TBX21-1993T/C did not influence the pattern of bacterial infection or the clinical parameters of disease severity, being the presence/absence of red complex bacteria the main factor associated with the disease status and the subrogate variable probing depth (PD) in the logistic regression analysis.

H2 O2 activates matrix metalloproteinases through the nuclear factor kappa B pathway and Ca(2+) signals in human periodontal fibroblasts

BACKGROUND

The mechanisms involved in reactive oxygen species and matrix metalloproteinase (MMP)-mediated periodontal tissue breakdown are unknown.

OBJECTIVE

To determine the effect of H2 O2 in MMP-2 and MMP-9 activity, and the involvement of nuclear factor kappa B (NFκB) and Ca(2+) -mediated signals in human periodontal ligament fibroblasts.

MATERIAL AND METHODS

Primary cultures were characterized for their phenotype and exposed for 24 h to sublethal doses (2.5-10 μm) of H2 O2 or control media. NFκB involvement was evaluated through immunofluorescence of p65 subunit, using the NFκB blocking peptide SN50 and catalase. Ca(2+) signals were analyzed by loading the cells with Fluo4-AM and recording the fluorescence changes in a confocal microscope before and after the addition of H2 O2 . 1,2-bis(o-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl was used to chelate intracellular Ca(2+) . The activity and levels of MMP-2 and MMP-9 were analyzed by gelatin zymogram and densitometric scanning, and enzyme-linked immunosorbent assay, respectively. Statistical analysis was performed with stata V11.1 software using the ANOVA test.

RESULTS

H2 O2 at concentrations of 2.5-5 μm induced Ca(2+) signaling and NFκB subunit p65 nuclear translocation, whereas catalase, SN50 and BAPTA-AM prevented p65 nuclear translocation. H2 O2 at 2.5-5 μm significantly increased MMP-9 and MMP-2 activity, while SN50 resulted in lower MMP-2 and MMP-9 activity rates compared with controls.

CONCLUSION

Sublethal H2 O2 induces Ca(2+) -dependent NFκB signaling with an increase in MMP gelatinolytic activity in human periodontal ligament.

Matrix metalloproteinases regulate extracellular levels of SDF-1/CXCL12, IL-6 and VEGF in hydrogen peroxide-stimulated human periodontal ligament fibroblasts

Periodontitis is a highly prevalent infectious disease characterized by the progressive inflammatory destruction of tooth-supporting structures, leading to tooth loss. The underling molecular mechanisms of the disease are incompletely understood, precluding the development of more efficient screening, diagnostic and therapeutic approaches. We investigated the interrelation of three known effector mechanisms of the cellular response to periodontal infection, namely reactive oxygen species (ROS), matrix metalloproteinases (MMPs) and cytokines in primary cell cultures of human periodontal ligament fibroblast (hPDLF). We demonstrated that ROS increase the activity/levels of gelatinolytic MMPs, and stimulate cytokine secretion in hPDLF. Additionally, we proved that MMPs possesses immune modulatory capacity, regulating the secreted levels of cytokines in ROS-stimulated hPDLF cultures. This evidence provides further insight in the molecular pathogenesis of periodontitis, contributing to the future development of more effective therapies.

Simultaneous analysis of T helper subsets (Th1, Th2, Th9, Th17, Th22, Tfh, Tr1 and Tregs) markers expression in periapical lesions reveals multiple cytokine clusters accountable for lesions activity and inactivity status

Previous studies demonstrate that the balance between pro- and anti-inflammatory mediators determines the stable or progressive nature of periapical granulomas by modulating the balance of the osteoclastogenic factor RANKL and its antagonist OPG. However, the cytokine networks operating in the development of periapical lesions are quite more complex than what the simple pro- versus anti-inflammatory mediators' paradigm suggests. Here we simultaneously investigated the patterns of Th1, Th2, Th9, Th17, Th22, Thf, Tr1 and Tregs cytokines/markers expression in human periapical granulomas.

METHODS

The expression of TNF-α, IFN-γ, IL-17A, IL23, IL21, IL-33, IL-10, IL-4, IL-9, IL-22, FOXp3 markers (via RealTimePCR array) was accessed in active/progressive (N=40) versus inactive/stable (N=70) periapical granulomas (as determined by RANKL/OPG expression ratio), and also to compare these samples with a panel of control specimens (N=26). A cluster analysis of 13 cytokine levels was performed to examine possible clustering between the cytokines in a total of 110 granulomas.

RESULTS

The expression of all target cytokines was higher in the granulomas than in control samples. TNF-α, IFN-γ, IL-17A and IL-21 mRNA levels were significantly higher in active granulomas, while in inactive lesions the expression levels of IL-4, IL-9, IL-10, IL-22 and FOXp3 were higher than in active granulomas. Five clusters were identified in inactive lesion groups, being the variance in the expression levels of IL-17, IL-10, FOXp3, IFN-γ, IL-9, IL-33 and IL-4 statistically significant (KW p<0.05). Three clusters were identified in active lesions, being the variance in the expression levels of IL-22, IL-10, IFN-γ, IL-17, IL-33, FOXp3, IL-21 and RANKL statistically significant (KW p<0.05).

CONCLUSION

There is a clear dichotomy in the profile of cytokine expression in inactive and active periapical lesions. While the widespread cytokine expression seems to be a feature of chronic lesions, hierarchical cluster analysis demonstrates the association of TNF-α, IL-21, IL-17 and IFN-γ with lesions activity, and the association of FOXP3, IL-10, IL-9, IL-4 and IL-22 with lesions inactivity.

Strategies to direct the enrichment, expansion, and recruitment of regulatory cells for the treatment of disease

Disease and injury perturb the balance of processes associated with inflammation and tissue remodeling, resulting in positive feedback loops, exacerbation of disease and compromised tissue repair. Conversely, under homeostatic healthy conditions, these processes are tightly regulated through the expansion and/or recruitment of specific cell populations, promoting a balanced steady-state. Better understanding of these regulatory processes and recent advances in biomaterials and biotechnology have prompted strategies to utilize cells for the treatment and prevention of disease through regulation of inflammation and promotion of tissue repair. Herein, we describe how cells that regulate these processes can be increased in prevalence at a site of disease or injury. We review several relevant cell therapy approaches as well as new strategies for directing endogenous regulatory cells capable of promoting environmental homeostasis and even the establishment of a pro-regenerative micro-environment. Collectively, these examples may provide a blueprint for next-generation "medicine" that spurs the body's own cells to action and replaces conventional drugs.

High levels of CXC ligand 12/stromal cell-derived factor 1 in apical lesions of endodontic origin associated with mast cell infiltration

INTRODUCTION

CXC ligand 12/stromal-derived factor-1 (CXCL12/SDF-1) is a pleiotropic chemokine that regulates the influx of a wide range of leukocytes. The aim of this study was to characterize CXCL12/SDF-1 in apical lesions (ALs) of endodontic origin, with special emphasis in associated immune cell populations.

METHODS

In this case-control study, 29 individuals with chronic apical periodontitis and 21 healthy volunteers were enrolled. ALs and healthy periodontal ligament samples were obtained for tissue homogenization, immune Western blotting, and enzyme-linked immunosorbent assay to determine CXCL12/SDF-1 forms and levels. Anatomopathologic diagnosis, immunostaining for CXCL12/SDF-1, CD117-CXCL12/SDF-1, and toluidine blue were also performed to identify tissue and cell localization. Finally, a set of tissue samples were digested and analyzed by flow cytometry to identify CXCL12/SDF-1 in different immune cell populations. Data were analyzed with Stata v11 and WinDi 2.9 software, and significance was considered if P < .05.

RESULTS

CXCL12/SDF-1 was predominantly identified as monomers; levels of CXCL12/SDF-1 were significantly higher in ALs compared with controls, and it was primarily localized to inflammatory infiltrates. Expression of CXCL12/SDF-1 was colocalized to mast cells in tissue sections. Furthermore, CD117(+) mast cells were the second most frequent infiltrating cells and the main CXCL12/SDF-1 expressing cells, followed by CD4(+) lymphocytes, monocytes/macrophages, neutrophils, and dendritic cells.

CONCLUSIONS

ALs of endodontic origin demonstrated higher levels of CXCL12/SDF-1 compared with controls. CXCL12/SDF-1 was identified in immune cell populations, whereas mast cells represented the major CXCL12/SDF-1 expressing cells, suggesting that this chemokine might play a central role in apical tissue destruction, most probably inducing persistent recruitment of immune cells, particularly of mast cells.