Platelets' Role in Dentistry: From Oral Pathology to Regenerative Potential

Comparing the effect of using calcified autogenous nano dentin particles versus micro dentin particles in the healing of mandibular bony defects in New Zealand rabbits

OBJECTIVE

This study aimed to compare the regenerative effect of autogenous micro-dentin and nano-dentin particles on bone regeneration in rabbits' mandibular defects. Sixty adult New Zealand rabbits were randomly divided into three groups: a control group, a micro-dentin group, and a nano-dentin group. A critical-sized bony defect was created at the lower border of the mandible. Bone regeneration was evaluated at two, four, and eight weeks using light microscopy, cone beam computed tomography (CBCT) scans, and histomorphometric analysis.

RESULTS

Nano-dentin significantly enhanced bone density and defect closure, as evidenced by CBCT and histological analyses. At eight weeks, it promoted extensive new bone formation, nearly bridging the defect, with minimal residual graft material compared to the micro-dentin group. Histomorphometric analysis confirmed its superior osteogenic potential, demonstrating enhanced bone regeneration and graft resorption. These findings highlight nano-dentin as a highly effective biomaterial for mandibular bone repair.

Establishing Minimum Criteria for Stem Cells from Human Exfoliated Deciduous Teeth (SHEDs) Cultured in Human Platelet Lysate (hPL)-Contained Media as Cell Therapy Candidates: Characterization and Predictive Analysis of Secretome Effects

SHEDs have demonstrated significant potential in cell therapy due to their superior proliferation rate, self-renewal and differentiation capacity (particularly neurogenesis attributed to their neural crest origin), and the less invasive procedure required for tissue collection compared to other stem cells. However, there is no established criterion to verify the minimum qualification to select one from numerous candidates, especially for SHEDs' cultured FBS-free medium for clinic application. For that, we performed a characteristic analysis containing the growth rate, colony-forming unit (CFU) number, average colony size, and migration capacity with hPL-cultured SHEDs from 21 different donors, and we suggest the result as a minimum standard to filter out unqualified candidates. In addition, in the secretome analysis to predict the paracrine effect, it was found that upregulated proteins compared to the control were related to angiogenesis, immune response, and BMP signaling, and this was found to have a strong correlation only with protein concentration. This study presents a minimum standard for selecting cell therapy candidates and suggests the protein concentration of a conditioned medium as a cost-effective tool to expect the paracrine effect of SHEDs.

Salivary microbiome profile shifts after scaling in stunted children

OBJECTIVE

Stunting is a condition of impaired growth in children resulting from chronic malnutrition, characterized by shorter stature compared to peers of the same age. This condition leads to salivary gland dysfunction, which triggers oral dysbiosis and increases the risk of periodontal disease in children. Scaling and root planing (SRP) is the gold standard treatment for periodontal disease, aimed at reducing pathogenic bacterial populations. This study aimed to evaluate the effect of SRP treatment on the oral microbiome profile in the saliva of stunted children. A pre- and post-test study design was employed, involving 10 elementary school children divided into two groups: normal children and stunted children. Each participant underwent scaling, with saliva samples collected before and after the procedure. The oral microbiome profile was analyzed using next-generation sequencing, generating taxonomic data at the phylum, genus, and species level.

RESULT

Statistical analysis revealed significant changes in the gingival index, a clinical parameter, in the normal group but not in the stunted group. Scaling resulted in shifts in the microbiome profile in both groups, with the dominant phyla identified as Proteobacteria, Bacteroidota, and Firmicutes. Scaling procedure alters the oral microbiome profile in stunted children without affecting the clinical parameter.

Vertical and horizontal bone loss following alveolar socket preservation using bone grafts and autologous platelet concentrates vs bone grafts alone: a systematic review and meta-analysis

BACKGROUND

Socket preservation is a proactive approach that limits bone loss after tooth extraction to maintain adequate bone volume, height and width. Many methods have proven effective in achieving socket preservation, including using various bone grafts and autologous platelet concentrates (APCs). Combining these two methods may lead to improved results in socket preservation and patient outcomes.

AIMS

To compare the combined use of APCs and bone grafts in socket preservation, with the use of bone grafts alone. Primary outcomes were radiographic vertical bone loss (VBL) and horizontal bone loss (HBL).

METHODS

A search on Pubmed, Scopus, Embase and Google Scholar databases was conducted to identify human studies using APCs in extraction sockets between January 2014 and August 2024. The inclusion criteria involved comparative human studies ranging from evidence levels II to III (Oxford Centre for Evidence-Based Medicine Levels of Evidence). For assessing bias in the included studies, the Cochrane Risk of Bias tools were used. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to determine the quality of evidence available.

RESULTS

A total of five randomised controlled trials (RCTs) were included in the analysis. Studies included the use of platelet rich fibrin (PRF), injectable platelet rich fibrin (i-PRF), advanced platelet rich fibrin (A-PRF), advanced platelet rich fibrin plus (A-PRF+) and concentrated growth factors (CGF). The risk of bias was judged high and moderate for two out of five RCTs. The analysis revealed a combined effect size for VBL reduction, with a standardized mean difference (SMD) of -0.83 (p < 0.001; 95% confidence interval (CI) = [-1.2, -0.57]; I² = 73.13%). For HBL reduction, the combined effect size was SMD = -0.72 (p < 0.001; 95% CI = [-1.08, -0.37]; I² = 68.34%). The overall evidence quality rating for the use of APCs in combination with bone grafts to reduce VBL during socket preservation was assessed as moderate, whereas to reduce HBL it was determined to be low.

CONCLUSION

The current literature demonstrates the added benefits of APCs combined with bone grafts in alveolar socket preservation compared to bone grafts alone in reducing vertical and horizontal bone loss. However, based on the GRADE assessment, the quality of evidence was judged low-to-moderate. Further randomised clinical studies would increase the certainty of the evidence.

A Comparison of the Dimensional Characteristics and Plasma Parameters of Different Centrifuges Used for the Preparation of Autologous Platelet Concentrates: A Randomized Correlational Study

OBJECTIVE

The objective of this study was to evaluate autologous platelet-rich fibrin (PRF) membrane weights and measurements after production by different centrifuges. Moreover, the values obtained with blood cellular components were correlated.

METHODS

Twelve systemically healthy participants underwent dental implant surgery associated with PRF membranes as the graft biomaterial at the implant site. Prior to the surgical procedure, the chosen participants underwent blood count and coagulogram tests and presented on the surgical day. Nine tubes containing 10 mL of venous blood were collected from each individual. The tubes were randomly distributed and positioned in three different centrifuges: (C1) the Intra-lock L-PRF Process, (C2) the Kasvi Digital, and (C3) the PRF Montserrat. PRF membrane processing was carried out as described by each manufacturer. After the processing steps, the prepared wet PRFs (initial) were placed in the container (box) designated by the manufacturer for the obtention of PRF membranes. The weights and measurements of the "wet" PRFs (initial) and membranes (final) were obtained using a precision scale and digital caliper in an aseptic environment. The data were compared, and the statistical differences were analyzed using the Friedman test and the Dunn post hoc test; Pearson correlation tests were performed between macroscopic data and data from serum tests; statistical significance was set at 5% (p < 0.05).

RESULTS

108 blood collection tubes were collected. The average harvest time for each tube individually was 21.5 ± 9.9 s. The average time for blood collection (nine tubes) from each of the 12 individuals was 193.1 ± 72.4 s (p = 0.728). The average values were very similar between the centrifuges, both for the measurements and weights of the "plugs" as well as for the linear measurements (p > 0.05). Regarding the wet weights and the linear averages of the PRF membranes, it was observed that the wet PRF weights varied from 0.22 to 0.25 mg and the linear measurements from 24.1 to 26.7 mm, with no statistical differences between centrifuges (p > 0.05). The data presented by centrifuges C1 and C2 were more homogeneous, delivering a value of less than 25% variability compared to the C3 centrifuge, which achieved values greater than 33%.

CONCLUSIONS

The proposed macroscopic dimensional evaluation found no differences between the autologous platelet concentrates obtained by different centrifuges, and no correlation was found between these PRFs and the patients' blood counts.

Role of Laboratory Tests in Enhancing Diagnosis and Treatment Planning for Dentists: A Review of Evidence-Based Practices

The purpose of this review is to simplify and guide dentists through the main laboratory investigations frequently used in dentistry for diagnosis and patient management. It emphasizes the critical role of laboratory tests in dental practice, highlighting their significance for accurate diagnosis, effective treatment planning, and ongoing monitoring of oral health. Systemic conditions often manifest through oral symptoms, making laboratory assessments essential for identifying undiagnosed health issues that may impact dental treatment outcomes. A comprehensive literature search was conducted using PubMed and Google Scholar to gather relevant studies, ensuring a thorough examination of existing knowledge on the subject. This review defines commonly used laboratory tests, including complete blood count (CBC), coagulation tests, hemoglobin A1c (HbA1c), liver function tests, immunological assays, and microbiological and virological evaluations. Each test provides valuable insights into patient health, aiding in the detection of conditions such as anemia, diabetes, and liver disease, which can complicate dental procedures. By adopting an evidence-based, personalized approach to patient care, dental professionals can enhance safety and treatment success. This article underscores the necessity of integrating laboratory assessments into routine dental practice, promoting a holistic understanding of patient health and improving overall treatment outcomes.

The Use of Platelet-Rich Fibrin (PRF) in the Management of Dry Socket: A Systematic Review

Dry socket or alveolar osteitis is a common postoperative complication following tooth extraction, characterized by severe pain due to the disintegration of the blood clot within the socket. Various factors contribute to its development, such as traumatic extraction, patient age and sex, smoking, and anesthetic use. To mitigate this condition, socket preservation techniques, including the use of bone substitute materials, have been employed. Platelet-rich fibrin (PRF) has emerged as a promising biomaterial, enhancing healing and reducing the incidence of dry socket. Materials and Methods: This systematic review, adhering to the PRISMA guidelines and registered with PROSPERO (ID: CRD 578018), examines the efficacy of PRF in managing dry socket by analyzing studies from PubMed, Scopus, and Web of Science published between January 2013 and May 2024. Boolean keywords have been used in the search strategy: ("Treatment") AND ("Dry Socket") AND ("Platelet Rich Fibrin" OR "PRF"). A total of 738 publications were found using the electronic database search. After the screening phase, 13 records were chosen for qualitative analysis. The results from multiple clinical trials and comparative studies indicate that PRF significantly reduces postoperative pain, expedites healing, and lowers the incidence of Alveolar Osteitis. Despite promising results, further large-scale, randomized studies are needed to validate PRF as a standard treatment for dry socket.

Platelet Storage-Problems, Improvements, and New Perspectives

Platelet transfusions are routine procedures in clinical treatment aimed at preventing bleeding in critically ill patients, including those with cancer, undergoing surgery, or experiencing trauma. However, platelets are susceptible blood cells that require specific storage conditions. The availability of platelet concentrates is limited to five days due to various factors, including the risk of bacterial contamination and the occurrence of physical and functional changes known as platelet storage lesions. In this article, the problems related to platelet storage lesions are categorized into four groups depending on research areas: storage conditions, additive solutions, new testing methods for platelets (proteomic and metabolomic analysis), and extensive data modeling of platelet production (mathematical modeling, statistical analysis, and artificial intelligence). This article provides extensive information on the challenges, potential improvements, and novel perspectives regarding platelet storage.

The role of platelets in central hubs of inflammation: A literature review

Platelets are increasingly recognized for their multifaceted roles in inflammation beyond their traditional involvement in haemostasis. This review consolidates knowledge on platelets as critical players in inflammatory responses. This study did an extensive search of electronic databases and identified studies on platelets in inflammation, focusing on molecular mechanisms, cell interactions, and clinical implications, emphasizing recent publications. Platelets contribute to inflammation via surface receptors, release of mediators, and participation in neutrophil extracellular trap formation. They are implicated in diseases like atherosclerosis, rheumatoid arthritis, and sepsis, highlighting their interaction with immune cells as pivotal in the onset and resolution of inflammation. Platelets are central to regulating inflammation, offering new therapeutic targets for inflammatory diseases. Future research should explore specific molecular pathways of platelets in inflammation for therapeutic intervention.

Dose-response effect of Montelukast on post-extraction dental socket repair and skeletal phenotype of mice

Bone metabolism and repair are directly regulated by arachidonic acid metabolites. At present, we analyzed the dose-response effects of a selective cysteinyl leukotriene receptor type-1 antagonist during bone repair after tooth extraction and on non-injured skeleton. Sixty-three 129 Sv/Ev male mice composed the groups: C-Control (saline solution); MTK2-2 mg/Kg of Montelukast (MTK) and MTK4-4 mg/Kg of MTK, daily administered by mouth throughout all experimental periods set at 7, 14, and 21 days post-operative. Dental sockets were analyzed by computed microtomography (microCT), histopathology, and immunohistochemistry. Femurs, L5 vertebra and organs were also removed for observation. Blood was collected for plasma bone and liver markers. Histopathology and microCT analysis revealed early socket repair of MTK2 and MTK4 animals, with significant increased BV/TV at days 14 and 21 compared to C. Higher plasma calcium was detected at days 7 and 21 in MTK4 in comparison to C, while phosphate was significantly increased in MTK2 in the same periods in comparison to C and MTK4. No significant differences were found regarding plasma ALP and TRAP, neither for local TRAP and Runx2 immunolabeling at the healing sockets. Organs did not present histological abnormalities. Increased AST levels have been detected in distinct groups and periods. In general, femur phenotype was improved in MTK treated animals. Collectively, MTK promoted early bone formation after tooth extraction and increased bone quality of femurs and vertebra in a time-dose-dependent manner, and should be considered as an alternative therapy when improved post-extraction socket repair or skeleton preservation is required.

Knowledge of handling medical emergencies among general dental practitioners pan India: a cross-sectional survery

BACKGROUND

Medical emergency situations in dental clinics have been contemplated to be an issue in most of the countries by reason of dentist's lack of knowledge and preparedness to attend emergency situations in dental offices. The aim of this paper is to observe the knowledge, attitude, and perceived confidence of the general dental practitioners regarding emergency medical care and its practical application. Questionnaire on knowledge assessment was circulated among 500 dentists using printed questionnaire formats and various social media platforms. The questionnaire included details on treating hypertensive patients, cardiopulmonary resuscitation training, accessibility of medical emergency equipments in the dental clinics, prevalence of medical emergency cases in the dental office and the self-assessed competence to handle medical emergency situations in the dental clinics. Data was surveyed and scrutinized using the Statistical Package for Social Sciences (SPSS), version 17 (SPSS Inc., Chicago IL). Descriptive statistics was tabulated and Chi square tests was applied.

FINDINGS

500 general dental practitioners pan India were involved in the study (294 were females and 207 were males). They were grouped into different age groups (20-30 yrs, 30-40 yrs, 40-50 yrs, 50 and above) and experience (0-5 yrs, 5-10 yrs and more than 10 years). 279 participants did not attend any medical emergency training whereas, 222 participants from all groups attended training program. It was observed that with increased experience in the field, the knowledge, awareness and confidence to treat medical emergency situation in the dental clinics was better. Dentists should update themselves from time-to-time with the latest technologies in the field and need to attend training programs to handle any medical emergency situations in the dental offices. Medical emergencies in a dental clinic can be encountered at any point of time and the clinician should have apt knowledge in handling such situations. Majority of the dentists feel subdued in managing medical situations in dental offices. Training and workshops for handling medical situations in the dental offices should be mandated at the undergraduate and postgraduate levels. This will help the dentist to shape one's confidence in managing such situations without apprehension. Availability of proper infrastructure and equipments is recommended in every dental clinics so as to ease the handling of the situation.

CONCLUSION

This paper enlightens the need of basic life support training on regular basis among the dentists to improve the competence among them and to improve the confidence in handling such situations.

Encapsulation of human endometrial stem cells in chitosan hydrogel containing titanium oxide nanoparticles for dental pulp repair and tissue regeneration in male Wistar rats

This study aimed to determine the impact of human endometrial stem cells (EnSCs) and titanium oxide nanoparticles (TiO₂ NPs) on dental pulp repair and regeneration in an animal model through dentine development and tissue regeneration. The EnSCs were put on a three-dimensional (3D) chitosan scaffold containing TiO₂ NPs after obtaining and purifying the collagenase enzyme. Pulps were exposed on the maxillary left first molar of all rats followed by direct pulp capping with the experimental scaffolds, as follows. Groups were: 1, control group without any treatment; 2, chitosan group (CS); 3, chitosan group with stem cells (CS/SCs); 4, chitosan group with stem cells and TiO₂ NPs (CS/EnSCs/TiO₂). Glass ionomer was used as a sealant in all groups. The teeth were extracted and histologically evaluated after 8 weeks. The quality and amount of dentine in the CS/EnSCs/TiO₂ group were higher than in the other groups. The combination of EnSCs with TiO₂ NPs and 3D chitosan scaffolds had a synergistic effect on each other, evidencing increased speed and quality of dentine formation. Using EnSCs with TiO₂ NPs on a 3D chitosan scaffold can be a suitable combination for direct pulp capping and dentine regeneration in a rat molar tooth model.

Regeneration of periodontal bone defects with mesenchymal stem cells in animal models. Systematic review and meta-analysis

The aim of this study was to evaluate the efficacy of mesenchymal stem cells (MSCs) in the regeneration of periodontal bone defects in animal models. A systematic review and meta-analysis were conducted following the PRISMA guidelines, and the study was recorded in PROSPERO under reference number CDR42021247462. The PICO question was: is periodontal regeneration (cementum, periodontal ligament and alveolar bone) with MSCs more effective than other techniques? Three groups were considered: Group 1: MSCs alone or mixed with regenerative materials. Group 2: only regenerative materials. Group 3: no regenerative material nor MSCs. The search was conducted using MeSH with a total of 18 articles for qualitative analysis and 5 for quantitative analysis. For the meta-analysis, a modification of the effect size algorithm was developed, which considered a comparison of means between treatments using the Student's t sample distribution. When comparing the effect size between Group 1 and Group 2, the effect size for the new cementum was 2.83 mm with an estimated confidence interval of 95% (CI 95%) between 0.48 and 5.17 mm. When considering the fit to a random-effects model, the combined variance (τ²) was 6.1573 mm, with a standard deviation (SD) of 5.6008 mm and a percentage of total heterogeneity I² of 92.33% (p < 0.0001). For new bone, the effect size was 0.88 mm, CI 95% - 0.25 to 2.01 mm, τ² = 1.3108 mm (SD = 1.2021 mm) and I² = 80.46%, p = 0.0004). With regard to the new periodontal ligament, it was not possible for the meta-analysis to be performed. MSCs have a greater capacity for tissue regeneration in root cementum than in alveolar bone compared to other regenerative materials.

A Bibliometric Analysis of Platelet-Rich Fibrin in Dentistry

Platelet-rich fibrin (PRF), a second-generation platelet concentrate, has been widely recognized in numerous studies for its performance of wound healing and regeneration in dentistry. However, bibliometric analysis of PRF in dentistry is still scarce. Thus, this study aimed to conduct and delineate a bibliometric analysis of the application of PRF and its changing trend in dentistry. All papers concerning PRF up to 30 June 2022 were included in the literature search from the Web of Science Core Collection database. These data were then entered into Microsoft Excel, analyzed by the SAS statistical software, and visualized by the VOSviewer software. A total of 562 articles were retrieved following the exclusive criteria. The results demonstrated that the trend of annual publication increased continually (p for trend < 0.01), more notably in the last five years. The majority of the articles were original (58.01%), followed by reviews (17.08%), and case reports (10.14%). The three major study designs were clinical studies (20.11%), randomized controlled trials (17.62%), and review/meta-analysis (17.08%). PRF was most frequently employed in oral surgery (31.14%), periodontal regeneration (22.42%), and implant therapy (18.68%). Turkey (16.19%), India (12.28%) and China (7.12%) were the top 3 countries publishing PRF studies. By comparing the total number of publications, total citation counts and varying counting methods, a combination of numerous counting methods was suggested for use since each counting method yields different results. Taken together, we hope with these informative findings, researchers could focus on the future direction or advancement in PRF, laying a foundation for evidence-based dentistry.

Human Platelets Contain, Translate, and Secrete Azurocidin; A Novel Effect on Hemostasis

Platelets play a significant role in hemostasis and perform essential immune functions, evidenced by the extensive repertoire of antimicrobial molecules. Currently, there is no clear description of the presence of azurocidin in human platelets. Azurocidin is a 37 kDa cationic protein abundant in neutrophils, with microbicidal, opsonizing, and vascular permeability-inducing activity. Therefore, this work aimed to characterize the content, secretion, translation, and functions of azurocidin in platelets. Our results show the presence of azurocidin mRNA and protein in α-granules of platelet and megakaryoblasts, and stimulation with thrombin, ADP, and LPS leads to the secretion of free azurocidin as well as within extracellular vesicles. In addition, platelets can translate azurocidin in a basal or thrombin-induced manner. Finally, we found that the addition of low concentrations of azurocidin prevents platelet aggregation and activation. In conclusion, we demonstrate that platelets contain, secrete, and translate azurocidin, and this protein may have important implications for hemostasis.

Rac Inhibition Causes Impaired GPVI Signalling in Human Platelets through GPVI Shedding and Reduction in PLCγ2 Phosphorylation

Rac1 is a small Rho GTPase that is activated in platelets upon stimulation with various ligands, including collagen and thrombin, which are ligands for the glycoprotein VI (GPVI) receptor and the protease-activated receptors, respectively. Rac1-deficient murine platelets have impaired lamellipodia formation, aggregation, and reduced PLCγ2 activation, but not phosphorylation. The objective of our study is to investigate the role of Rac1 in GPVI-dependent human platelet activation and downstream signalling. Therefore, we used human platelets stimulated using GPVI agonists (collagen and collagen-related peptide) in the presence of the Rac1-specific inhibitor EHT1864 and analysed platelet activation, aggregation, spreading, protein phosphorylation, and GPVI clustering and shedding. We observed that in human platelets, the inhibition of Rac1 by EHT1864 had no significant effect on GPVI clustering on collagen fibres but decreased the ability of platelets to spread or aggregate in response to GPVI agonists. Additionally, in contrast to what was observed in murine Rac1-deficient platelets, EHT1864 enhanced GPVI shedding in platelets and reduced the phosphorylation levels of PLCγ2 following GPVI activation. In conclusion, Rac1 activity is required for both human and murine platelet activation in response to GPVI-ligands, but Rac1's mode of action differs between the two species.