Pulpal Response Research Articles

TRAUMATISMOS DENTAIS NA INFÂNCIA E SUAS IMPLICAÇÕES NA POLPA: REVISÃO DE LITERATURA

Childhood dental trauma is common, especially in the 2-7 age group, and affects the upper central incisors more due to their exposure in impact situations. When the trauma involves the dental pulp, the treatment is to preserve the vitality of the tooth, with pulp capping and pulpotomy procedures being the most recommended. Currently, there has been a shift from invasive practices to conservative techniques in order to minimize long-term damage and improve the child's prognosis. The International Association of Dental Traumatology (IADT) guidelines contribute to this conservative approach, affirming the importance of immediate treatment and follow-up to avoid complications. The objective of this study is to demonstrate the implications of dental trauma in childhood, as well as how the pulp reacts to trauma. This literature review is based on articles published between 2014 and 2024, searched in the Scielo, Pubmed, Google Scholar and Periódico Capes databases. It was possible to conclude that, when subjected to trauma, the affected tooth may present some pulp responses, with pulp necrosis was the most frequent alteration.

Correction: Histopathological pulp response to nano zirconia versus nano clay modified glass ionomers: An experimental study

Correction: Histopathological pulp response to nano zirconia versus nano clay modified glass ionomers: An experimental study

Effect of four direct pulp capping agents on human dental pulp tissue.

Direct pulp capping (DPC) is a vital pulp therapy, wherein accidental or carious pulp exposures can be capped with various materials to induce reparative dentine formation. One of the major factors that determine the success of direct pulp capping procedures is the material used. Therefore, it is of interest to evaluate and compare the efficacy of a new material, Tristrontium aluminate in comparison with the widely used materials such as ProRoot MTA, Biodentine & TheraCal LC. Hence, 40 premolars scheduled for extraction for orthodontic treatment, were equally divided into 4 groups and iatrogenic DPC was done using one of the study materials. The premolars were then extracted after 90 days & assessed for the formation of Dentine Bridge and pulpal response elicited by the materials using CBCT and histopathological analysis. All the materials tested in the study were successful in inducing dentine bridge formation & maintaining pulp vitality. Thus, the novelty of Tristrontium aluminate for potential applications in future is eminent.

Histological response of inflamed pulp to hydraulic calcium silicate cements in direct pulp capping: Systematic review of pulpitis models.

This systematic review aimed to compare the histological response of inflamed pulpodentinal complex to the hydraulic calcium silicate cements in experimental animal models of pulpitis. Articles that evaluated the histological response of inflamed pulp to mineral trioxide aggregate (MTA) in comparison with other restorative materials were selected and analysed in detail. The risk of bias assessment was conducted using SYRCLE's RoB tool. The GRADEpro tool was used to determine the overall quality of evidence. Out of the 2947 retrieved articles from databases, five articles fulfilled the inclusion criteria. MTA induced significantly more hard tissue formation compared to calcium hydroxide. The use of pulp-capping material containing fluocinolone acetonide and ASP/PLGA-ASP/ACP/PLLA-PLGA composite membrane was comparable. This systematic review could not demonstrate enhanced efficiency of capping materials compared to MTA. Future well-conducted animal studies are warranted for demonstrating the hard tissue formation abilities of pulp-capping materials with convenient inflammatory conditions.

Treatment outcomes of pulpotomy versus pulpectomy in vital primary molars diagnosed with symptomatic irreversible pulpitis: protocol for a non-inferiority randomised controlled trial

BackgroundPulpectomy continues to be the standard treatment recommendation for management of vital primary molars diagnosed with symptomatic irreversible pulpitis. The recent decade has seen a paradigm shift in the treatment concepts of how vital mature permanent molars diagnosed with irreversible pulpitis can be more conservatively managed using vital pulp therapy techniques like pulpotomy. However, despite emerging evidence indicating similarities between primary and permanent tooth pulp response to dental caries, there is limited research on whether pulpotomy can be similarly used as a definitive treatment modality for vital primary teeth with irreversible pulpitis. This randomised controlled trial (RCT) aims to compare the treatment effectiveness of pulpotomy versus pulpectomy in management of vital primary molars diagnosed with symptomatic irreversible pulpitis over a two-year period.Methods/designThis clinical study is a parallel, two-armed, open label, non-inferiority RCT with a 1:1 allocation ratio between the experimental intervention arm (pulpotomy) and the active comparator arm (pulpectomy). Healthy cooperative children, between 4–9 years of age, who have painful primary molars with clinical symptoms typical of irreversible pulpitis will be recruited after obtaining informed consent from their parents/legal guardians. 50 vital primary molars clinically diagnosed with symptomatic irreversible pulpitis will be randomly distributed between the two treatment arms. The primary outcomes that will be assessed are clinical and radiographic success after six-months, one-year and two-years of the trial interventions. The influence of baseline pre-operative variables (age; gender; tooth type; site of caries; pre-operative furcal radiolucency; pre-operative pain intensity) and intra-operative factors (time taken to achieve haemostasis) on treatment outcomes will also be assessed. The secondary outcome evaluated will be the immediate (24 h and 7 d) post-operative pain relief afforded by the two treatment interventions.DiscussionThis trial seeks to provide evidence on whether pulpotomy treatment can be no worse than the standard pulpectomy treatment for the management of symptomatic irreversible pulpitis in vital primary molars.Trial registrationClinicalTrials.gov (NCT06183203). Registered on 30 January 2024.

Biological evaluation of novel phosphorylated pullulan-based calcium hydroxide formulations as direct pulp capping materials: An invivo study on a rat model.

Calcium hydroxide (CH) has been considered as a direct pulp capping materials (DPC) for the last decades despite having some limitations. Phosphorylate pullulan (PPL) incorporated with CH (CHPPL) is a novel biomaterial that was introduced as a promising DPC material. Thus, the aim of the study was to evaluate the inflammatory response and mineralized tissue formation (MTF) ability of PPL-based CH formulations on rat molars after DPC. This study consisted of six groups: CH with 1% PPL (CHPPL-1); 3% PPL (CHPPL-3); 5% PPL (CHPPL-5); Dycal and NEX MTA Cement (N-MTA) as the positive control, and no capping materials (NC). One hundred twenty maxillary first molar cavities were prepared on Wistar rats. After capping, all the cavities were restored with 4-META/MMA-TBB resin and pulpal responses were evaluated at days 1, 7, and 28. Kruskal-Wallis followed by Mann-Whitney U-test was performed with a significance level of 0.05. Immunohistochemical expression of IL-6, Nestin, and DMP-1 was observed. At day 1, CHPPL-1, N-MTA, and Dycal exhibited no to mild inflammation, whilst CHPPL-3, CHPPL-5, and NC showed mild to moderate inflammation, and the results were significantly different (p < .05). At day 7, mild to moderate inflammation was observed in CHPPL-1, N-MTA, and Dycal, whereas CHPPL-3, CHPPL-5, and NC exhibited moderate to severe inflammation. Significant differences were observed between CHPPL-1 and N-MTA with NC (p < .05), CHPPL-1 and CHPPL-3 with CHPPL-5 and Dycal (p < .05), and CHPPL-3 with N-MTA (p < .05). A thin layer of mineralized tissue formation (MTF) was observed in all groups. At day 28, CHPPL-1, Dycal, and N-MTA showed no to mild inflammation, whilst CHPPL-3, CHPPL-5, and NC exhibited mild to severe inflammation, and statistically significant difference was detected (p < .05). CHPPL-1, Dycal, and N-MTA exhibited continuous MTF, whilst CHPPL-3, CHPPL-5, and NC had thicker and interrupted MTF. Significant differences were observed between CHPPL-1, CHPPL-3, and N-MTA with NC group (p < .05). Variable expressions of IL-6, Nestin, and DMP-1 indicated differences in the materials' impact on odontoblast-like cell formation and tissue mineralization. These findings suggest that CHPPL-1 has the potential to minimize pulpal inflammation and promote MTF and had similar efficacy as MTA cement.

Assessment of dental pulp response to carries via MR T2mapping and histological analysis

ObjectivesThe aim of our study was to assess the correlation between T2 relaxation times and their variability with the histopathological results of the same teeth in relation to caries progression. Materials and methods: 52 extracted permanent premolars were included in the study. Prior to extractions, patients underwent magnetic resonance imaging (MRI) scanning and teeth were evaluated using ICDAS classification. Pulps of extracted teeth were histologically analysed. Results: MRI T2 relaxation times (ms) were 111,9 ± 11.2 for ICDAS 0, 132.3 ± 18.5* for ICDAS 1, 124.6 ± 14.8 for ICDAS 2 and 112. 6 ± 18.2 for ICDAS 3 group (p = 0,013). A positive correlation was observed between MRI T2 relaxation times and macrophage and T lymphocyte density in healthy teeth. There was a positive correlation between vascular density and T2 relaxation times of dental pulp in teeth with ICDAS score 1. A negative correlation was found between T2 relaxation times and macrophage density. There was a positive correlation between T2 relaxation time variability and macrophage and T lymphocyte density in teeth with ICDAS score 2. In teeth with ICDAS score 3, a positive correlation between T2 relaxation times and T2 relaxation time variability and lymphocyte B density was found. Conclusion: The results of our study confirm the applicability of MRI in evaluation of the true condition of the pulp tissue. Clinical relevance: With the high correlation to histological validation, MRI method serves as a promising imaging implement in the field of general dentistry and endodontics.

Evaluation of pulpal response to Endosequence root repair versus Biodentine after pulpotomy in primary teeth of puppies

Evaluation of pulpal response to Endosequence root repair versus Biodentine after pulpotomy in primary teeth of puppies

Correlation between pulp sensibility and magnetic resonance signal intensity following regenerative endodontic procedures in mature necrotic teeth- a retrospective cohort study

BackgroundWith increasing studies being published on regenerative endodontic procedures (REPs) as a treatment modality for mature necrotic teeth, the assessment of outcomes following regenerative endodontic procedures has become more challenging and the demand for a better understanding of the regenerated tissues following this treatment is rising. The study aimed to correlate cold, electric pulp testing (EPT), and magnetic resonance imaging (MRI) signal intensity (SI) in mature necrotic teeth treated with regenerative endodontic procedures.MethodologyThis retrospective cohort study included eighteen adult patients who experienced tooth necrosis in mature maxillary anterior teeth recruited from the outpatient clinic, Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt from July 2017 until December 2018 with 12 months of follow-up. regenerative endodontic procedures via blood clot were performed. The canals were instrumented by ProTaper Next (PTN) files until final sizes X3 or X5. Biodentine was used as cervical plug material. Pre and post-operative clinical follow-up was done where the patients’ responses to cold and electric pulp testing were given a scoring system and were compared to the normal contralateral tooth. Pre and post-operative magnetic resonance imaging signal intensity of both the involved tooth and its contralateral at the middle and the apical thirds of the root canals were assessed after 3, 6, and 12 months. Data was analyzed using the ANOVA, Friedman and Bonferroni tests. Significance was set at a p-value < 0.05.ResultsAll 18 teeth scored a baseline score of “2” for cold and electric pulp testing. There was a significant difference between scores of the cold test at baseline and 12-month follow-up (p < 0.001). There was a significant difference between scores of the electric pulp testing of baseline and 12-month follow-up (p < 0.001). There was a moderately significant indirect (inverse) correlation between magnetic resonance imaging signal intensity and cold test in both the middle and apical thirds at 12 months. No significant correlations were detected between magnetic resonance imaging signal intensity and electric pulp testingat any of the time intervals (p > 0.05).ConclusionMagnetic resonance imaging is a successful non-invasive method to assess outcomes of regenerative endodontic procedures and correlating it with another reliable method of assessing pulpal responses, cold test, could validate these outcomes.Clinical trial registrationThe study was registered with ClinicalTrials.gov (ID: NCT03804450).

Hard tissue formation in pulpotomized primary teeth in dogs with nanomaterials MCM-48 and MCM-48/hydroxyapatite: an in vivo animal study

BackgroundThis animal study sought to evaluate two novel nanomaterials for pulpotomy of primary teeth and assess the short-term pulpal response and hard tissue formation in dogs. The results were compared with mineral trioxide aggregate (MTA).MethodsThis in vivo animal study on dogs evaluated 48 primary premolar teeth of 4 mongrel female dogs the age of 6–8 weeks, randomly divided into four groups (n = 12). The teeth underwent complete pulpotomy under general anesthesia. The pulp tissue was capped with MCM-48, MCM-48/Hydroxyapatite (HA), MTA (positive control), and gutta-percha (negative control), and the teeth were restored with intermediate restorative material (IRM) paste and amalgam. After 4–6 weeks, the teeth were extracted and histologically analyzed to assess the pulpal response to the pulpotomy agent.ResultsThe data were analyzed using the Kruskal‒Wallis, Fisher’s exact, Spearman’s, and Mann‒Whitney tests. The four groups were not significantly different regarding the severity of inflammation (P = 0.53), extent of inflammation (P = 0.72), necrosis (P = 0.361), severity of edema (P = 0.52), extent of edema (P = 0.06), or connective tissue formation (P = 0.064). A significant correlation was noted between the severity and extent of inflammation (r = 0.954, P < 0.001). The four groups were significantly different regarding the frequency of bone formation (P = 0.012), extent of connective tissue formation (P = 0.047), severity of congestion (P = 0.02), and extent of congestion (P = 0.01). No bone formation was noted in the gutta-percha group. The type of newly formed bone was not significantly different among the three experimental groups (P = 0.320).ConclusionMCM-48 and MCM-48/HA are bioactive nanomaterials that may serve as alternatives for pulpotomy of primary teeth due to their ability to induce hard tissue formation. The MCM-48 and MCM-48/HA mesoporous silica nanomaterials have the potential to induce osteogenesis and tertiary (reparative) dentin formation.

Histological Evaluation of Pulpal Response and Dentin Bridge Formation After Direct Pulp Capping Using Recombinant Amelogenin and Mineral Trioxide Aggregate (MTA).

The purpose of the study was to compare and histologically investigate pulpal response and dentin bridge formation after direct pulp capping using recombinant amelogenin and mineral trioxide aggregate (MTA). Recombinant amelogenin protein and MTA were used as pulp capping materials in 120 teeth from eight mongrel dogs. Dogs were sacrificed at two different evaluation times. Regenerative changes were evaluated histologically. At two weeks, in contrast to the MTA group, most of the amelogenin group showed moderately formed hard tissue formation and the pulp tissue was completely filling the entire pulp chamber. These results were statistically significant. At two months, all the samples of the amelogenin group showed complete dentin bridge formation and the pulp chamber was filled entirely with tissue-mimicking the authentic pulp in all the specimens of the amelogenin group. These results were statistically significant. In conclusion, direct pulp capping by recombinant amelogenin protein resulted in significantly better regeneration of the dentin-pulp complex than MTA.

Two-Dimensional Radiographs and Cone-beam Computed Tomography Assessment of Concentrated Growth Factor and Platelet-Rich Fibrin Scaffolds in Regenerative Endodontic Treatment of Immature Incisors with Periapical Radiolucency: A Randomized Clinical Trial

IntroductionThe primary aim of this study was to compare the radiographic changes of immature incisors with periapical radiolucency after treatment with platelet-rich fibrin (PRF) and concentrated growth factor (CGF) platelet concentrate scaffolds as well as assessment of the clinical success rate over 12 months. The secondary aim was to monitor the radiographic changes in terms of reduction of periapical lesion diameter (PALD), root dentine thickness (RDT), root length (RL), and apical foramen width (AFW). The tertiary aim was to assess and pulp responses, after 12 months. MethodsFifty six children with seventy necrotic, single-rooted maxillary incisors with periapical radiolucency were treated with either CGF or PRF scaffolds (35 teeth per group). Two patients with 4 teeth (2 teeth in each group) failed to attain the follow-up recalls. Radiographic changes in terms of reduction of PALD, RDT, RL, and AFW were monitored using a 2-dimensional (2D) radiograph and cone-beam computed tomography (CBCT) scan. The clinical performance of teeth receiving both scaffolds was assessed after 6 and 12 months. Categorical and continuous data were analyzed using the chi-square test and the t test, respectively. The time and group effects on the means of different radiographic dimensions were tested using the general linear model. Bland-Altman plots were used to assess the level of agreement between the 2D radiographs and CBCT. The level of significance was defined at 0.05 and a 95% confidence interval. ResultsThe means of PALD and RL showed significant enhancement in the CGF group compared to the PRF group (P < .05). While the difference between the 2 scaffolds in terms of RDT and AFW was not significant (P > .05). The findings of the 2D radiograph and CBCT were consistent. Clinically, both scaffold success rates were similar (93.9%) over the follow-up intervals. The influence of study independent variables had no significant effect on the success of the regenerative endodontic procedures outcome (P > .05). There was no significant difference in the positive pulp responses to the thermal and electric pulp tests after one year of treatment (P > .05). ConclusionsAccording to the short-term follow-up, PRF and CGF were successful in treating immature teeth with periapical radiolucency by regenerative endodontics. Both scaffold systems induced periapical healing and root lengthening with significant superiority of CGF.

Histological evaluation of the regenerative potential of a novel photocrosslinkable gelatin-treated dentin matrix hydrogel in direct pulp capping: an animal study

BackgroundTo assess histologically the success of the pulp capping approach performed in traumatically exposed dogs’ teeth using a novel injectable gelatin-treated dentin matrix light cured hydrogel (LCG-TDM) compared with LCG, MTA and TheraCal LC.MethodsSixty-four dogs’ teeth were divided into two groups (each including 32 teeth) based on the post-treatment evaluation period: group I: 2 weeks and group II: 8 weeks. Each group was further subdivided according to the pulp capping material into four subgroups (n = 8), with subgroup A (light-cured gelatin hydrogel) as the control subgroup, subgroup B (LCG-TDM), subgroup C (TheraCal LC), and subgroup D (MTA). Pulps were mechanically exposed in the middle of the cavity floor and capped with different materials. An assessment of periapical response was performed preoperatively and at 8 weeks. After 2 and 8-week intervals, the dogs were sacrificed, and the teeth were stained with hematoxylin-eosin and graded by using a histologic scoring system. Statistical analysis was performed using the chi-square and Kruskal-Wallis tests (p = 0.05).ResultsAll subgroups showed mild inflammation with normal pulp tissue at 2 weeks with no significant differences between subgroups (p ≤ 0.05), except for the TheraCal LC subgroup, which exhibited moderate inflammation (62.5%). Absence of a complete calcified bridge was reported in all subgroups at 2 weeks, while at 8 weeks, the majority of samples in the LCG-TDM and MTA-Angelus subgroups showed complete dentin bridge formation and absence of inflammatory pulp response with no significant differences between them (p ≤ 0.05). However, the formed dentin in the LCG-TDM group was significantly thicker, with layers of ordered odontoblasts identified to create a homogeneous tubular structure and numerous dentinal tubule lines suggesting a favourable trend towards dentin regeneration. TheraCal LC samples revealed a reasonably thick dentin bridge with moderate inflammation (50%) and LCG showed heavily fibrous tissue infiltrates with areas of degenerated pulp with no signs of hard tissue formation.ConclusionsLCG-TDM, as an extracellular matrix-based material, has the potential to regenerate dentin and preserve pulp vitality, making it a viable natural alternative to silicate-based cements for healing in vivo dentin defects in direct pulp-capping procedures.

The road map to proper dental pulp experiments in animal models

Animal models are essential for the development and comparison of new dental materials. However, working on the dental pulp of animal models can be challenging. To provide guidance for conducting proper dental pulp experiments in animal models. The author conducted a literature search on the Google Scholar database to find papers related to pulp capping and animal modeling in dentistry. Based on her own experience in animal research and the findings from the literature review, the author provides practical advice for new researchers in this field. Dogs and monkeys have the size and morphology of teeth that facilitate accessibility while operating in the dental pulp. However, the response of rat dental pulp has been found to be identical to that of humans. Rat maxillary molars are often used for dental pulp studies. Anesthesia using a combination of ketamine and xylazine provides a suitable time for pulp procedures in rats, but it's important to note that anesthetized rats may remain alert despite receiving the correct dose. Attempting to increase the dosage can result in the rat being unable to recover from anesthesia. To ensure safe and effective anesthesia, it is recommended to administer only one-third of the ketamine dose. Xylazine re-dosing should be avoided. Dental researchers in the Middle East and Africa may face unique challenges, but working on rats is challenging worldwide. In the future, virtual reality and simulation may offer alternatives for experimental animals. Wister Albino is the more suitable animal model to be used in dental pulp experiments. The checklist and flow chart of PRAISE 2021 are mandatory for dental researchers experimenting with the dental pulp of animal models.

Pulp Sensitivity Testing in Multiple Sclerosis: Disease Duration and Sensory/Motor Associations-A Cross-Sectional Study.

Introduction: This study explores a relatively unexplored aspect of multiple sclerosis (MS) by examining the sensitivity threshold of dental pulp as a potential indicator of neuropathy in MS patients. Building upon earlier research that focused on assessing the response to electrical pulp testing in MS patients who did not have a history of trigeminal neuralgia, this survey is aimed at delving into the relationship between MS duration and the threshold for stimulation in response to pulp sensitivity tests. Materials and Methods: This study encompassed a total of 124 maxillary central incisors from patients diagnosed with relapsing-remitting multiple sclerosis (RRMS). The participants were uniform in terms of age, falling within the 18-50 years range, and all had RRMS with no history of trigeminal neuralgia. The electric pulp sensitivity test was conducted on all samples, and the results of the electric pulp testing (EPT) were recorded according to the grade of the pulp tester that elicited a response. The threshold was considered reached when the patient first experienced a burning sensation after EPT application and the use of 1,1,1,2-tetrafluoroethane spray. Data analysis employed paired t-tests, Fisher's exact test, and Spearman correlation, with a significance level set at p < 0.05. Results: Based on the study's findings, the average response value to EPT was 2.69 ± 1.17, while the response time to the cold test was 2.61 ± 1.03 s. There was no statistically significant difference in the response to the cold test based on age (p = 0.45). However, it was observed that the mean response time to the cold test was significantly longer among male participants (p = 0.001). No significant differences were identified in the pulpal response to EPT or the cold test between patients with and without sensory-motor involvement (p > 0.05). Furthermore, Spearman's analysis revealed a noteworthy positive correlation between the electrical pulp threshold and the time taken to respond to the cold test (p = 0.025, r = 0.2). Conclusions: The utilization of the pulpal sensitivity test in MS patients holds promise for practical clinical use. Notably, individuals with a more extended duration of the disease exhibited a notably elevated threshold for both the EPT and the cold test conducted on their maxillary central incisors.

Histological evaluation of pulp response to alendronate and Biodentine as pulp capping agents: an animal study

Histological evaluation of pulp response to alendronate and Biodentine as pulp capping agents: an animal study

Histopathological pulp response of teeth capped with calcium aluminate cement and biodentine: Experimental study on rodents

Histopathological pulp response of teeth capped with calcium aluminate cement and biodentine: Experimental study on rodents

Advancing dentin-pulp regeneration: clinical perspectives and insights from stem/progenitor cell transplantation (part II).

This systematic review evaluates clinical studies investigating regenerative endodontic procedures for mature/immature teeth utilizing stem cell transplantation. An electronic search of Scopus, PubMed, ISI Web Science, and Google Scholar was conducted up to January 2023. Outcome measures encompassed radiographic (periapical lesion, root length, apical foramen width, volume of the regenerated pulp) and clinical (post-operative pain, sensibility test) parameters. Among 3250 identified articles, five clinical studies were selected, comprising two randomized controlled trials (RCTs) for mature/immature teeth, and three case reports/series for mature teeth. Despite the promising potential, the included studies exhibited a notable risk of bias. The diversity in stem cells (e.g., dental pulp stem cells [DPSCs], umbilical cord mesenchymal stem cells [UC-MSCs]), scaffolds (Atecollagen, collagen membrane, platelet-poor plasma [PPP], leukocyte platelet-rich in fibrin [L-PRF]), and growth factors (granulocyte colony-stimulating factor [G-CSF]) emphasized the heterogeneity across interventions. In RCTs, DPSCs application increased root length and reduced apical foramen width in immature teeth, while UC-MSCs transplantation reduced apical lesions in mature teeth. Transplantation of DPSCs aggregates or UC-MSCs/PPP also elicited positive pulp responses and increased blood flow. In case reports/series, DPSCs application in teeth with irreversible pulpitis resulted in mineralization and increased the regenerated pulp' volume. Furthermore, transplantation of DPSCs with G-CSF/atelocollagen or L-PRF/collagen membrane led to positive pulp responses. While underscoring the potential of stem cell transplantation for regenerative endodontics in mature/immature teeth, the overall evidence quality and the limited number of available studies emphasize the need for cautious interpretation of results. Future well-designed clinical studies are essential to validate these findings further.

Immunohistochemical Localization of Substance P in Pulp Tissue After In-Office Bleaching Technique in Rats

Currently in-office bleaching procedure is the most frequently used in dentistry which represents the most traditional way to modify the color of teeth. The objective of the study is to investigate the pulp response to in-office bleaching procedure with two different concentration of bleaching products by immunohistochemical assessment for Substance P which represent main neuropeptide located in the sensory nerves of the pulp. Twenty four male albino rats were randomly divided equally into two groups. The right maxillary molars were subjected to a single in-office bleaching session with 40% of hydrogen peroxide (Opalescence Boost, UT, USA) (group A) and with 30% of hydrogen peroxide (Philips Dash, USA) (group B). The left maxillary molars in both groups received no treatment used as (negative control). the pulp response were evaluated in 1st day (n=6) and 7th day (n=6) after bleaching procedure. The upper jaws were processed for H&amp;E stain and immunohistochemical localization of substance P. At 1st day there was high mean value of dental pulp cells that positively expressed for substance P antibody in both bleached groups and mostly in 40% bleached group (group A 30.133, group B 27.267) than control group (10.358) with significant p value (0.013) while at 7th day this expression was reduced in both groups(mean value of group A was 15.300 while the group B was 11.400). In conclusion the higher the concentration of hydrogen peroxide in bleaching products the further damage to the pulp represents in neurogenic inflammation which explain the increasing in substance P expression.

Effects of direct pulp capping with recombinant human erythropoietin and/or mineral trioxide aggregate on inflamed rat dental pulp.

This study aimed to evaluate the dental pulp responses to recombinant human erythropoietin (rhEPO) and/or mineral trioxide aggregate (MTA) in pulp capping of inflamed dental pulp in vivo. In accordance with ARRIVE guidelines, pulp inflammation was induced by exposing the maxillary first molars (n = 64) of Wistar rats (n = 32) to the oral environment for two days. The exposed pulps were randomly assigned four groups based on the pulp capping material: rhEPO, MTA, MTA + rhEPO, or an inert membrane. An additional eight rats formed the healthy control group. After four weeks, the animals were euthanized, and histological, qRT-PCR, and spectrophotometric techniques were employed to analyze the left maxillary segments, right first maxillary molars, and blood samples, respectively. Statistical significance was set at p < 0.05 and < 0.001. Pulp capping with rhEPO, MTA, or MTA + rhEPO resulted in lower inflammation and higher mineralization scores compared to untreated control. MTA + rhEPO group exhibited significantly decreased expression of tumor necrosis factor-alpha, and interleukin 1-beta, while MTA group showed substantially reduced expression of interferon-gamma. Both rhEPO and MTA + rhEPO groups presented elevated dentin matrix protein 1 levels compared to untreated control. Furthermore, pulp capping with rhEPO and/or MTA led to increased transforming growth factor-beta 1 expression and reductions of pro-inflammatory/immunoregulatory cytokine ratios and prooxidative markers. Pulp capping with rhEPO also resulted in increase of systemic antioxidative stress markers. Capping with rhEPO or MTA + rhEPO resulted in a favorable effect that was similar or even superior to that of MTA.