Multiplexed LC-MS/MS quantification of salivary RNA modifications in periodontitis.

OBJECTIVE: To analyse the salivary epitranscriptomic profiles as periodontitis biomarkers using multiplexed mass spectrometry (MS). BACKGROUND: The field of epitranscriptomics, which relates to RNA chemical modifications, opens new perspectives in the discovery of diagnostic biomarkers, especially in periodontitis. Recently, the modified ribonucleoside N6-methyladenosine (m6A) was revealed as a crucial player in the etiopathogenesis of periodontitis. However, no epitranscriptomic biomarker has been identified in saliva to date. MATERIALS AND METHODS: Twenty-four saliva samples were collected from periodontitis patients (n = 16) and from control subjects (n = 8). Periodontitis patients were stratified according to stage and grade. Salivary nucleosides were directly extracted and, in parallel, salivary RNA was digested into its constituent nucleosides. Nucleoside samples were then quantified by multiplexed MS. RESULTS: Twenty-seven free nucleosides were detected and an overlapping set of 12 nucleotides were detected in digested RNA. Among the free nucleosides, cytidine and three other modified nucleosides (inosine, queuosine and m6Am) were significantly altered in periodontitis patients. In digested RNA, only uridine was significantly higher in periodontitis patients. Importantly there was no correlation between free salivary nucleoside levels and the levels of those same nucleotides in digested salivary RNA, except for cytidine, m5C and uridine. This statement implies that the two detection methods are complementary. CONCLUSION: The high specificity and sensitivity of MS allowed the detection and quantification of multiple nucleosides from RNA and free nucleosides in saliva. Some ribonucleosides appear to be promising biomarkers of periodontitis. Our analytic pipeline opens new perspectives for diagnostic periodontitis biomarkers.

Prevalence and Associated Factors of Self-Reported Gingival Bleeding: A Multicenter Study in France.

Gingival bleeding (GB) is a common sign of gingival inflammation which indicates the presence of periodontal diseases. This cross-sectional multicenter survey aimed to assess the prevalence of self-reported gingival bleeding (SRGB) in French adults and identify the main associated factors. A questionnaire-based interview was randomly proposed to 794 individuals in four French cities (Nancy, Montpellier, Paris, and Rennes). Subjects were recruited in preventive medicine centers (50%), railway stations, and malls (50%). The questionnaire comprised 25 items: SRGB characteristics, socioeconomic variables, oral hygiene habits, use of drugs, and anxiety level. The overall prevalence of SRGB was 63.2% [59.8%; 66.6%], with 58.7% bleeding after toothbrushing and 4.5% spontaneous bleeding. Males reported significantly lower SRGB prevalence than females (p = 0.04). The distribution of SRGB frequency was inversely proportional to age (p < 0.0001). No association between drug use and SRGB was found. The people interviewed in the preventive medicine centers reported the highest frequency of SRGB (p < 0.0001). In the multivariate logistic model, SRGB was significantly related to occupation, smoking status, brushing frequency, and anxiety level. In conclusion, SRGB was prevalent in more than half of the sample and was mainly associated with age, toothbrushing frequency, and anxiety level. Thus, providing information to patients about the importance of this oral manifestation may play an important role in preventing periodontal diseases.

Perception of Gingival Bleeding by People and Healthcare Professionals: A Multicentre Study in an Adult French Population.

Gingival bleeding (GB) is a common sign of gingival inflammation, which indicates the presence of periodontal diseases. This study aimed to describe the perception of French adults about their self-reported GB and answers of healthcare professionals regarding the GB reported by these interviewees. A questionnaire administered by one investigator in each of three public settings of four cities in France from September 2016 to November 2017. Among 794 adults interviewed, 502 (63.2%) reported a GB. Among them, 414 (82.5%) believed that GB is benign, and 309 (61.6%) declared one or more responses. The three main responses were to use mouthwash (29.3%), to change to a soft-bristle toothbrush (20.1%) and to modify the brushing technique (19.3%). Almost half (49.0%) questioned at least one healthcare professional concerning their GB: a dentist (43.0%), a physician (14.1%), and a pharmacist (8.0%). The main response of each healthcare professional was: for dentists: a "prescription of mouthwash", for physicians to say "gingival bleeding is not serious"; and for pharmacists: "to sell a mouthwash". Most of the participants considered their GB as benign and had inappropriate responses, which indicates their lack of knowledge regarding periodontal health. The same conclusions can be drawn for healthcare professionals, as reported by interviewees.

A Five-year Comparative Study of Perceived Stress Among Dental Students at Two European Faculties.

AIM: To compare the levels, causes and the impact of stress from cohort of fifthyear dental students in the Faculties of Dental Medicine in Plovdiv, Bulgaria and Montpellier, France. MATERIALS AND METHODS: The questionnaire we used comprised the modified version of the 56-item Dental Environment Stress (DES) questionnaire. It was completed by fifth-year undergraduate dental students in both faculties in 2011 and 2016, totaling 335 dental students. A five-point Likert scale was used to record the responses from the subjects. Statistical analysis was performed with STATA version 14.1 (StataCorp, College Station, USA) specialized software. RESULTS: The mean age of studied population was not significantly different between 2011 and 2016 (p=0.08). The common stress value per student was 1.74 (CI: 1.64; 1.84, range: 0.12; 4.50). It was higher in Plovdiv (1.79±0.81) than in Montpellier (1.63±0.66); it was statistically higher for girls (1.94±0.70) than for boys (1.49±0.77), and decreased between 2011 and 2016. A significant overall effect of the common mean stress was influenced by the town (p=0.008), year of study (p=0.003), gender (p=0.0001) and accommodation (p=0.01) of the student. CONCLUSION: Academicals and clinical factors of stress are prevailing stressors during education. The challenge is now to decrease the influence of both, without altering the quality of dental education. Regular discussions and debriefs about the clinical cases before and after clinical activity. Alternative methods of education and examination, such as interactive methods, could be considered in order to reduce the stress of theoretical exams.

Multicenter study of patients' preferences and concerns regarding the origin of bone grafts utilized in dentistry.

PURPOSE: Bone graft materials can be obtained from the patient's own body (autologous graft), animals (xenograft), human cadavers (allograft) and synthetic materials (alloplastic bone graft). Patients may have ethical, religious or medical concerns about the origin of bone grafts, which could lead them to reject the use of certain types of bone graft in their treatments. The aim of this multicenter study, which surveyed patients from five university clinics in Portugal, France, Italy, Spain and Chile, was to analyze patients' opinions regarding the source of bone grafts. PATIENTS AND METHODS: A survey composed of ten questions was translated into local languages and validated. Patients were asked about the degree of acceptance/rejection of each graft and the reasons for rejection. A chi-squared test was used to analyze statistically significant differences. RESULTS: Three hundred thirty patients were surveyed. The grafts that elicited the highest percentage of refusal were allograft (40.4%), autologous bone graft from an extraoral donor site (34%) and xenograft (32.7%). The grafts with the lowest rate of refusal were alloplastic (6.3%) and autologous bone grafts from an intraoral donor site (24.5%). The main reason for autologous bone rejection was the fear of pain and discomfort, for xenograft it was the fear of disease transmission and the rejection of use of animals for human benefit, and for allograft it was ethical/moral motivations and the fear of disease transmission. Religious affiliation influenced patient's preferences. CONCLUSION: The origin of bone grafts is still conflictive for a high percentage of patients.

Pulp Regeneration Concepts for Nonvital Teeth: From Tissue Engineering to Clinical Approaches.

Following the basis of tissue engineering (Cells-Scaffold-Bioactive molecules), regenerative endodontic has emerged as a new concept of dental treatment. Clinical procedures have been proposed by endodontic practitioners willing to promote regenerative therapy. Preserving pulp vitality was a first approach. Later procedures aimed to regenerate a vascularized pulp in necrotic root canals. However, there is still no protocol allowing an effective regeneration of necrotic pulp tissue either in immature or mature teeth. This review explores in vitro and preclinical concepts developed during the last decade, especially the potential use of stem cells, bioactive molecules, and scaffolds, and makes a comparison with the goals achieved so far in clinical practice. Regeneration of pulp-like tissue has been shown in various experimental conditions. However, the appropriate techniques are currently in a developmental stage. The ideal combination of scaffolds and growth factors to obtain a complete regeneration of the pulp-dentin complex is still unknown. The use of stem cells, especially from pulp origin, sounds promising for pulp regeneration therapy, but it has not been applied so far for clinical endodontics, in case of necrotic teeth. The gap observed between the hope raised from in vitro experiments and the reality of endodontic treatments suggests that clinical success may be achieved without external stem cell application. Therefore, procedures using the concept of cell homing, through evoked bleeding that permit to recreate a living tissue that mimics the original pulp has been proposed. Perspectives for pulp tissue engineering in the near future include a better control of clinical parameters and pragmatic approach of the experimental results (autologous stem cells from cell homing, controlled release of growth factors). In the coming years, this therapeutic strategy will probably become a clinical reality, even for mature necrotic teeth.

Dental pulp stem cells used to deliver the anticancer drug paclitaxel.

BACKGROUND: Understanding stem cell behavior as a delivery tool in cancer therapy is essential for evaluating their future clinical potential. Previous in-vivo studies proved the use of mesenchymal stem cells (MSCs) for local delivery of the commonest anticancer drug, paclitaxel (PTX). Dental pulp is a relatively abundant noninvasive source of MSCs. We assess dental pulp stem cells (DPSCs), for the first time, as anticancer drug carriers. Confocal Raman microscopy is a unique tool to trace drug and cell viability without labeling. METHODS: Drug uptake and cell apoptosis are identified through confocal Raman microscope. We traced translocation of cytochrome c enzyme from the mitochondria, as a biomarker for apoptosis, after testing both cancer and stem cells. The viability of stem cells was checked by means of confocal Raman microscope and by cytotoxicity assays. RESULTS: In this study, we prove that DPSCs can be loaded in vitro with the anticancerous drug without affecting their viability, which is later released in the culture medium of breast cancer cells (MCF-7 cells) in a time-dependent fashion. The induced cytotoxic damage in MCF-7 cells was observed consequently after PTX release by DPSCs. Additionally, quantitative Raman images of intracellular drug uptake in DPSCs and MCF-7 cells were obtained. Cytotoxic assays prove the DPSCs to be more resistant to PTX as compared to bone marrow-derived MSCs, provided similar conditions. CONCLUSIONS: Applications of dental stem cells for targeted treatment of cancer could be a revolution to reduce morbidity due to chemotherapy, and to increase the efficacy of systemic cancer treatment.

Assessing a multiplex-targeted proteomics approach for the clinical diagnosis of periodontitis using saliva samples.

AIM: The present study focused on the research of new biomarkers based on the liquid chromatography-multiple-reaction monitoring (MRM) proteomic profile in whole saliva of patients with periodontitis compared with periodontal healthy patients. METHODS: A 30-min multiplexed liquid chromatography-MRM method was used for absolute quantification of 35 plasma biomarkers in saliva from control patients and patients with periodontitis. RESULTS: Three proteins namely hemopexin, plasminogen and α-fibrinogen were shown to be clearly related to the presence of periodontitis compared with healthy patients. Apolipoprotein H was found to discriminate for the first time chronic and aggressive periodontitis. CONCLUSION: Our results indicate that this innovative MRM method could be used to screen for periodontitis in clinical environment. Furthermore, apolipoprotein H was found to be a discriminant biomarker of aggressive periodontitis.

[Collaboration between periodontics and orthodontics: interest of alveolar corticotomies and piezocision. Review of literature]. / Collaboration parodontie et orthodontie : intérêts des corticotomies alvéolaires et de la piézocision. Revue de la littérature.

INTRODUCTION: Orthodontics in adults must adapt to certain particularities especially related to the decrease or absence of growth and the prevalence of periodontal damage in this population. This review of the literature aims to assess the effects of alveolar corticotomies on accelerating or facilitating tooth movements in different types of orthodontic movements, to compare results obtained by classical technique with those obtained by piezocision and analyze their impact on periodontal tissues in the long term. MATERIAL AND METHODS: Research was performed with Medline, Embase and Cochrane databases, beginning in January 2000. Every study, selected through its title and abstract, was then evaluated through its full content. A total of 65 studies were included. RESULTS: All studies showed that corticotomies temporarily facilitate accelerated orthodontic tooth movement, with minimal complications. No periodontal lesion, loss of pulpal vitality or severe root resorption were reported. DISCUSSION: Only a few studies have examined control groups treated with conventional orthodontics. Corticotomy allows temporary acceleration of orthodontic tooth movement. Piezocision is less invasive and performed in certain indications; it also lightens the postoperative complications. However, the fact that using alveolar corticotomies significantly decreases the treatment time remains uncertain, due to the lack of significant data. Further prospective randomized clinical studies are necessary to analyze more precisely the decrease in the overall treatment time, improved periodontal support and stability of orthodontic treatment results in the long term following the alveolar corticotomies.

Benefits of mineralized bone cortical allograft for immediate implant placement in extraction sites: an in vivo study in dogs.

PURPOSE: The aim of the present study was to evaluate the effectiveness of using a mineralized bone cortical allograft (MBCA), with or without a resorbable collagenous membrane derived from bovine pericardium, on alveolar bone remodeling after immediate implant placement in a dog model. METHODS: Six mongrel dogs were included. The test and control sites were randomly selected. Four biradicular premolars were extracted from the mandible. In control sites, implants without an allograft or membrane were placed immediately in the fresh extraction sockets. In the test sites, an MBCA was placed to fill the gap between the bone socket wall and implant, with or without a resorbable collagenous membrane. Specimens were collected after 1 and 3 months. The amount of residual particles and new bone quality were evaluated by histomorphometry. RESULTS: Few residual graft particles were observed to be closely embedded in the new bone without any contact with the implant surface. The allograft combined with a resorbable collagen membrane limited the resorption of the buccal wall in height and width. The histological quality of the new bone was equivalent to that of the original bone. The MBCA improved the quality of new bone formation, with few residual particles observed at 3 months. CONCLUSIONS: The preliminary results of this animal study indicate a real benefit in obtaining new bone as well as in enhancing osseointegration due to the high resorbability of cortical allograft particles, in comparison to the results of xenografts or other biomaterials (mineralized or demineralized cancellous allografts) that have been presented in the literature. Furthermore, the use of an MBCA combined with a collagen membrane in extraction and immediate implant placement limited the extent of post-extraction resorption.

Polyetheretherketone (PEEK) for medical applications.

Polyetheretherketone (PEEK) is a polyaromatic semi-crystalline thermoplastic polymer with mechanical properties favorable for bio-medical applications. Polyetheretherketone forms: PEEK-LT1, PEEK-LT2, and PEEK-LT3 have already been applied in different surgical fields: spine surgery, orthopedic surgery, maxillo-facial surgery etc. Synthesis of PEEK composites broadens the physicochemical and mechanical properties of PEEK materials. To improve their osteoinductive and antimicrobial capabilities, different types of functionalization of PEEK surfaces and changes in PEEK structure were proposed. PEEK based materials are becoming an important group of biomaterials used for bone and cartilage replacement as well as in a large number of diverse medical fields. The current paper describes the structural changes and the surface functionalization of PEEK materials and their most common biomedical applications. The possibility to use these materials in 3D printing process could increase the scientific interest and their future development as well.