Sensory nerves, but not sympathetic nerves, promote reparative dentine formation after dentine injury via CGRP-mediated angiogenesis: An in vivo study.

AIM: Dental pulp is richly innervated by nerve fibres, which are mainly involved in the sensation of pain. Aside from pain sensation, little is known regarding the role of dental innervation in reparative dentine formation. We herein generated a mouse model of experimental dentine injury to examine nerve sprouting within the odontoblast and subodontoblastic layers and investigated the potential effects of this innervation in reparative dentinogenesis. METHODOLOGY: Mouse tooth cavity model (bur preparation + etching) was established, and then nerve sprouting, angiogenesis and reparative dentinogenesis were determined by histological and immunofluorescent staining at 1, 3, 7, 14 and 28 days postoperatively. We also established the mouse-denervated molar models to determine the role of sensory and sympathetic nerves in reparative dentinogenesis, respectively. Finally, we applied calcitonin gene-related peptide (CGRP) receptor antagonist to analyse the changes in angiogenesis and reparative dentinogenesis. RESULTS: Sequential histological results from dentine-exposed teeth revealed a significant increase in innervation directly beneath the injured area on the first day after dentine exposure, followed by vascularisation and reparative dentine production at 3 and 7 days, respectively. Intriguingly, abundant type H vessels (CD31+ Endomucin+ ) were present in the innervated area, and their formation precedes the onset of reparative dentine formation. Additionally, we found that sensory denervation led to blunted angiogenesis and impaired dentinogenesis, while sympathetic denervation did not affect dentinogenesis. Moreover, a marked increase in the density of CGRP+ nerve fibres was seen on day 3, which was reduced but remained elevated over the baseline level on day 14, whereas the density of substance P-positive nerve fibres did not change significantly. CGRP receptor antagonist-treated mice showed similar results as those with sensory denervation, including impairments in type H angiogenesis, which confirms the importance of CGRP in the formation of type H vessels. CONCLUSIONS: Dental pulp sensory nerves act as an essential upstream mediator to promote angiogenesis, including the formation of type H vessels, and reparative dentinogenesis. CGRP signalling governs the nerve-vessel-reparative dentine network, which is mostly produced by newly dense sensory nerve fibres within the dental pulp.

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

BACKGROUND: This 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). METHODS: This 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. RESULTS: The 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). CONCLUSION: MCM-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 the regenerative potential of a novel photocrosslinkable gelatin-treated dentin matrix hydrogel in direct pulp capping: an animal study.

BACKGROUND: To 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. METHODS: Sixty-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). RESULTS: All 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. CONCLUSIONS: LCG-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.

Wnt3a promotes odonto/osteogenic differentiation in vitro and tertiary dentin formation in a rat model.

AIM: To investigate the effect of Wnt3a on odonto/osteogenic differentiation of stem cells isolated from human exfoliated deciduous teeth (SHEDs) and reparative dentine formation in a rat model. METHODOLOGY: Stem cells isolated from human exfoliated deciduous teeth were cultured in media with Wnt3a (50-200 ng/ml). Wnt activation was confirmed by ß-catenin immunocytochemistry. Colony-forming unit assay (normalized percentage area), osteogenic gene expression analysis by real-time polymerase chain reaction and mineralization assays measured by the absorption at 540 nm were performed. Tertiary dentine formation in vivo was evaluated using 8-week-old, male Wistar rats. Cavities with pinpoint pulp exposure by a sharp instrument were prepared at the mesial surface of the first molars. Teeth were divided into (n = 6): (1) distilled water (negative control), (2) phosphate-buffered saline (PBS), (3) lithium chloride in DI (20 µM), and (4) Wnt3a in PBS (200 ng/ml). Collagen sponge was used as a scaffold. The cavity was sealed with glass ionomer restoration. Four weeks later, animals were euthanized by sodium pentobarbital (120 mg/kg body weight). Hard tissue formation was evaluated using micro-computerized tomography. Sixty consecutive slides from the initial plane were analysed and calculated as bone/dentine volume per total tissue volume. Paraffin sections (2 µm) were stained with haematoxylin and eosin and Masson's trichrome for morphological evaluation. Data are presented as the mean ± standard error. Mann-Whitney U test was used for two-group comparison. Kruskal Wallis followed by pairwise comparison was employed for three or more group comparisons. Statistical analysis was performed using GraphPad Prism 7. Differences were considered significant at p < .05. RESULTS: Wnt3a decreased SHEDs colony formation and increased OSX, BMP2, and DMP1 expression, corresponding to an increase in mineralization. Additionally, a significant increase in dentine/bone volume per total tissue volume was observed in Wnt3a treated defects. Dentine bridge formation at the exposure sites treated with Wnt3a demonstrated, while fibrous tissues were observed in the control. CONCLUSIONS: Wnt3a suppressed proliferation, increased osteogenic differentiation of SHEDs and promotes tertiary dentine formation. Wnt3a could be utilized as biological molecule for vital pulp therapy.

Axin2-CreERT2 mediated knockout of bone morphogenetic protein receptor type 1A caused abnormal secondary dentine and altered cell fate of Axin2-expressing odontogenic cells.

AIM: Inducing odontogenic differentiation and tubular dentine formation is extremely important in dentine repair and tooth regeneration. Bone morphogenic proteins (BMPs) signalling plays a critical role in dentine development and tertiary dentine formation, whilst how BMPR1A-mediated signalling affects odontoblastic differentiation of Axin2-expressing (Axin2+ ) odontogenic cells and tubular dentine formation remains largely unknown. This study aims to reveal the cellular and molecular mechanisms involved in the formation of secondary dentine. METHODOLOGY: Axin2lacZ/+ mice harvested at post-natal 21 (P21) were used to map Axin2+ mesenchymal cells. Axin2CreERT2/+ ; R26RtdTomato/+ mice and Axin2CreERT2/+ ; R26RDTA/+ ; R26RtdTomato/+ mice were generated to observe the tempo-spatial distribution pattern of Axin2-lineage cells and the effect of ablation of Axin2+ cells on dentinogenesis, respectively. A loss-of-function model was established with Axin2CreERT2/+ ; Bmpr1afl/fl ; R26RtdTomato/+ (cKO) mice to study the role of BMP signalling in regulating Axin2+ cells. Micro-computed tomography, histologic and immunostainings, and other approaches were used to examine biological functions, including dentine formation, mineralization and cell differentiation in cKO mice. RESULTS: The results showed rich expression of Axin2 in odontoblasts at P21. Lineage tracing assay confirmed the wide distribution of Axin2 lineage cells in odontoblast layer and dental pulp during secondary dentine formation (P23 to P56), suggesting that Axin2+ cells are important cell source of primary odontoblasts. Ablation of Axin2+ cells (DTA mice) significantly impaired secondary dentine formation characterized with notably reduced dentine thickness (Mean of control: 54.11 µm, Mean of DTA: 27.79 µm, p = .0101). Furthermore, malformed osteo-dentine replaced the tubular secondary dentine in the absence of Bmpr1a with irregular cell morphology, abnormal cellular process formation and lack of cell-cell tight conjunction. Remarkably increased expression of osteogenic markers like Runx2 and DMP1 was detected, whilst DSP expression was observed in a dispersed manner, indicating an impaired odontogenic cell fate and failure in producing tubular dentine in cKO mice. CONCLUSIONS: Axin2+ cells are a critical population of primary odontoblasts which contribute to tubular secondary dentine formation, and BMP signalling pathway plays a vital role in maintaining the odontogenic fate of Axin2+ cells.

Nano eggshell-based slurry as a direct pulp-capping material: In vitro characterization and histopathological assessment in an experimental animal model.

AIM: Pulp vitality is essential for tooth integrity. Following pulp exposure, choosing a suitable pulp-capping material is crucial to maintain pulp vitality. However, the reparative dentine bridge created by calcium hydroxide (Ca(OH)2 ) is generally porous and incomplete. The aim of the current study is to assess the in vitro and in vivo bioactivities of nano eggshell-based slurry (NES), using NES as a direct pulp-capping material, compared with Ca(OH)2 in rabbit animal model. METHODOLOGY: Nano eggshell powder (NE) was characterized for particle morphology, chemical composition and ion release. In vitro bioactivity was tested by immersion in simulated body fluid (SBF) for 7 days. For histopathological evaluation, 36 adult New Zealand rabbits (72 pulp exposures) were divided into nine groups (n = 8) according to the pulp-capping material (NES, Ca(OH)2 and no capping as negative control group) and the animals were sacrificed after 7, 14 or 28 days. The pulps of the two lower central incisors were exposed and then directly capped by Ca(OH)2 or NES or left untreated. The cavities were then sealed with glass ionomer cement. Teeth were collected for histopathological evaluation using an optical microscope. Pulp haemorrhage, inflammation, fibrosis and calcific bridge formation were assessed. Results were statistically analysed using anova and Tukey's tests. RESULTS: Nano eggshell particles were spherical with a 20 nm diameter and were composed mainly of calcite. Statistical analysis showed that there was a significant increase in the release of all investigated ions between days 1 and 28, except for copper. NES group showed a significantly higher release of all elements as compared to Ca(OH)2 . Environmental scanning electron microscope micrographs of NES incubated for 7 days in SBF showed the formation of HAp with a Ca/P ratio (1.686). For histopathological evaluation, the difference between groups was statistically significant. At day 28, 75% of the pulps of the Ca(OH)2 group showed mild calcific bridge in comparison with 100% moderate calcific bridge in the NES group. The NES group showed significantly less inflammation at days 7 and 28, and higher fibrosis at day 7 compared with Ca(OH)2 . CONCLUSIONS: Nano eggshell-based slurry represents a promising novel direct pulp-capping material with favourable pulp tissue response.

3D-printed microgels supplemented with dentin matrix molecules as a novel biomaterial for direct pulp capping.

OBJECTIVES: To develop a 3D-printed, microparticulate hydrogel supplemented with dentin matrix molecules (DMM) as a novel regenerative strategy for dental pulp capping. MATERIALS AND METHODS: Gelatin methacryloyl microgels (7% w/v) mixed with varying concentrations of DMM were printed using a digital light projection 3D printer and lyophilized for 2 days. The release profile of the DMM-loaded microgels was measured using a bicinchoninic acid assay. Next, dental pulp exposure defects were created in maxillary first molars of Wistar rats. The exposures were randomly capped with (1) inert material - negative control, (2) microgels, (3) microgels + DMM 500 µg/ml, (4) microgels + DMM 1000 µg/ml, (5) microgels + platelet-derived growth factor (PDGF 10 ng/ml), or (6) MTA (n = 15/group). After 4 weeks, animals were euthanized, and treated molars were harvested and then processed to evaluate hard tissue deposition, pulp tissue organization, and blood vessel density. RESULTS: All the specimens from groups treated with microgel + 500 µg/ml, microgel + 1000 µg/ml, microgel + PDGF, and MTA showed the formation of organized pulp tissue, tertiary dentin, newly formed tubular and atubular dentin, and new blood vessel formation. Dentin bridge formation was greater and pulp necrosis was less in the microgel + DMM groups compared to MTA. CONCLUSIONS: The 3D-printed photocurable microgels doped with DMM exhibited favorable cellular and inflammatory pulp responses, and significantly more tertiary dentin deposition. CLINICAL RELEVANCE: 3D-printed microgel with DMM is a promising biomaterial for dentin and dental pulp regeneration in pulp capping procedures.

Clinical evaluation of surface treatment on clinical performance of non-carious sclerotic cervical lesions: 18-month follow-up.

PURPOSE: To evaluate the influence of different surface treatments on the clinical behavior of non-carious cervical sclerotic lesions (NCCLs) over an 18-month follow-up period. METHODS: 128 NCCLs from 32 volunteers were randomized into four groups (n=32): G1-control, without preoperative treatment of the dentin surface; G2, dentin conditioning with 17% ethylenediaminetetracetic acid (EDTA) for 2 minutes; G3, increase in dentin surface roughness with diamond bur and G4, increase in dentin surface roughness with diamond bur + dentin conditioning with 17% EDTA for 2 minutes. RESULTS: Differences between groups were tested using the Friedman test (α= 0.05). A questionnaire was administered to volunteers about risk factors related to NCCLs. The relationship between the questionnaire data and the clinical performance of the restorations was analyzed using the multiple logistic regression test (α= 0.05). The variables related to parafunctional habits, anxiety and/or depression were significantly related to the manifestation of postoperative sensitivity. Roughening the sclerotic dentin with a diamond bur increased postoperative sensitivity within 12 months. The presence of parafunctional habits and anxiety/depression may lead to postoperative sensitivity. CLINICAL SIGNIFICANCE: Roughening the sclerotic dentin with a diamond bur increased postoperative sensitivity within 12 months.

Biodegradation of an injectable treated dentin matrix hydrogel as a novel pulp capping agent for dentin regeneration.

BACKGROUND: A novel injectable mixture termed treated dentin matrix hydrogel (TDMH) has been introduced for restoring dentin defect in DPC. However, no study evaluated its physiological biodegradation. Therefore, the present study aimed to assess scaffold homogeneity, mechanical properties and biodegradability in vitro and in vivo and the regenerated dentin induced by TDMH as a novel pulp capping agent in human permanent teeth. METHODS: Three TDMH discs were weighted, and dry/wet ratios were calculated in four slices from each disc to evaluate homogeneity. Hydrogel discs were also analyzed in triplicate to measure the compressive strength using a universal testing machine. The in vitro degradation behavior of hydrogel in PBS at 37 °C for 2 months was also investigated by monitoring the percent weight change. Moreover, 20 intact fully erupted premolars were included for assessment of TDMH in vivo biodegradation when used as a novel injectable pulp capping agent. The capped teeth were divided into four equal groups according to extraction interval after 2-, 8-, 12- and 16-weeks, stained with hematoxylin-eosin for histological and histomorphometric evaluation. Statistical analysis was performed using F test (ANOVA) and post hoc test (p = 0.05). RESULTS: No statistical differences among hydrogel slices were detected with (p = 0.192) according to homogeneity. TDMH compression modulus was (30.45 ± 1.11 kPa). Hydrogel retained its shape well up to 4 weeks and after 8 weeks completely degraded. Histological analysis after 16 weeks showed a significant reduction in TDMH area and a simultaneous significant increase in the new dentin area. The mean values of TDMH were 58.8% ± 5.9 and 9.8% ± 3.3 at 2 and 16 weeks, while the new dentin occupied 9.5% ± 2.8 at 2 weeks and 82.9% ± 3.8 at 16 weeks. CONCLUSIONS: TDMH was homogenous and exhibited significant stability and almost completely recovered after excessive compression. TDMH generally maintained their bulk geometry throughout 7 weeks. The in vivo response to TDMH was characterized by extensive degradation of the hydrogel and dentin matrix particles and abundant formation of new dentin. The degradation rate of TDMH matched the rate of new dentin formation. TRIAL REGISTRATION: PACTR201901866476410: 30/1/2019.

Pulpal and periapical tissue response after direct pulp capping with endosequence root repair material and low-level laser application.

BACKGROUND: The study aims to investigate the pulp and periapical reaction and healing after capping with EndoSequence Root Repair Material (ERRM) combined with low-level laser application. METHODS: In 6 rabbits, pulps were exposed via class V, half of the samples received a low-level diode laser at 980 nm. Thereafter, cavities were capped with regular-set ERRM. The specimens were processed for histomorphological examination after 2 weeks and two months. RESULTS: After 2 weeks, images show mild inflammation and organized odontoblasts in lased group. The non-lased group shows more severe inflammation. The predentin thickness was thicker in the lased group with statistical significance (p < 0.05). After 2 months, inflammatory cells were sparse in both lased and non-lased groups. In the periapical area, group one showed dilated blood vessels and thick fibrous connective tissues. In group two, there were more numerous maturations of PDL fibers with scattered inflammatory cells and congested blood vessel. CONCLUSIONS: Using low-level laser therapy in combination with ERRM for pulp capping shortens the inflammatory phase and enhances healing.

Bioactive molecules for regenerative pulp capping.

Since the discovery of bioactive molecules sequestered in dentine, researchers have been exploring ways to harness their activities for dental regeneration. One specific area, discussed in this review, is that of dental-pulp capping. Dental-pulp caps are placed when the dental pulp is exposed due to decay or trauma in an attempt to enhance tertiary dentine deposition. Several materials are used for dental-pulp capping; however, natural biomimetic scaffolds may offer advantages over manufactured materials such as improved aesthetic, biocompatibility and success rate. The present review discusses and appraises the current evidence surrounding biomimetic dental-pulp capping, with a focus on bioactive molecules sequestered in dentine. Molecules covered most extensively in the literature include transforming growth factors (TGF-ßs, specifically TGF-ß1) and bone morphogenetic proteins (BMPs, specifically BMP-2 and BMP-7). Further studies would need to explore the synergistic use of multiple peptides together with the development of a tailored scaffold carrier. The roles of some of the molecules identified in dentine need to be explored before they can be considered as potential bioactive molecules in a biomimetic scaffold for dental-pulp capping. Future in vivo work needs to consider the inflammatory environment of the dental pulp in pulpal exposures and compare pulp-capping materials.

Dentine matrix metalloproteinases as potential mediators of dentine regeneration.

Matrix metalloproteinases (MMPs) have been implicated not only in the regulation of developmental processes but also in the release of biologically active molecules and in the modulation of repair during tertiary dentine formation. Although efforts to preserve dentine have focused on inhibiting the activity of these proteases, their function is much more complex and necessary for dentine repair than expected. The present review explores the role of MMPs as bioactive components of the dentine matrix involved in dentine formation, repair and regeneration. Special consideration is given to the mechanical properties of dentine, including those of reactionary and reparative dentine, and the known roles of MMPs in their formation. MMPs are critical components of the dentine matrix and should be considered as important candidates in dentine regeneration.

A full Bayesian calibration model for assessing age in adults by means of pulp/tooth area ratio in periapical radiography.

The Bayesian approach is being a fundamental tool in forensic and legal field where inferences and decisions are made. In this study, a full Bayesian calibration model was developed to make probabilistic inferences about age estimation in a reference sample of 891 periapical X-rays of upper and lower canines. These teeth belonged to both deceased and living adult subjects, aged between 20 and 86 years, coming from five different countries (Turkey, Italy, Portugal, Japan and Mexico). For this purpose, the narrowing of pulp chamber due to the apposition of secondary dentine was analysed by means of the pulp/tooth area ratio. To determine the agreement of the method, intra- and inter-observer differences for measuring process were calculated by means of the intraclass correlation coefficient (ICC) analysis. Observer error tests showed excellent agreement between observers and between repeated assessments. According to the results of the ANCOVA, neither nationality nor sex was associated to the secondary dentine apposition while it is associated with individual's age. The results of the present study indicated that the concept of probability is intrinsically linked to the assessment of age in a forensic context, and the Bayesian approach could be considered a robust tool to overtake the bias generated by traditional regression models, thus helping the decision-making process in a legal framework.

Histological evaluation of the regenerative potential of a novel treated dentin matrix hydrogel in direct pulp capping.

OBJECTIVES: To produce a novel injectable treated dentin matrix hydrogel (TDMH) to be used as a novel pulp-capping agent for dentin regeneration compared with Biodentine and MTA. MATERIALS AND METHODS: Thirty intact fully erupted premolars scheduled to be extracted for orthodontic reasons were included. Pulps were mechanically exposed in the middle of the cavity floor. TDMH was composed of TDM powder (500-µm particle size) and sodium alginate as an injectable scaffold. The capped teeth were divided into three equal groups (n = 10): TDMH, Biodentine, and MTA respectively. Clinical examination and assessment of periapical response were performed. The teeth were extracted after 2-weeks and 2-month intervals, stained with hematoxylin-eosin, and categorized by using a histologic scoring system. Statistical analysis was performed using chi-square and Kruskal-Wallis test (p = 0.05). RESULTS: All teeth were vital during observation periods. Histological analysis after 2 months showed complete dentin bridge formation and absence of inflammatory pulp response with no significant differences between groups. However, the formed dentin was significantly thicker with the TDMH group with layers of well-arranged odontoblasts that were found to form a homogenous tubular structure with numerous dentinal tubule lines showing a positive trend to dentin regeneration. CONCLUSIONS: TDMH could achieve dentin regeneration and conservation of pulp vitality and might serve as a feasible natural substitute for silicate-based cements in restoring in vivo dentin defect in direct pulp-capping procedure. TRIAL REGISTRATION: PACTR201901866476410.

Clinical, radiographic, and histological evaluation of three different pulp-capping materials in indirect pulp treatment of primary teeth: a randomized clinical trial.

OBJECTIVES: The aim of this randomized, controlled, three-arm parallel group, and double-blinded clinical trial was to evaluate the clinical, radiographic, and histopathological success of three different pulp-capping materials in one-stage indirect pulp treatment of primary teeth. MATERIALS AND METHODS: The study included a total of 109 patients aged 5-9 years who had primary teeth with deep carious lesions and symptoms of reversible pulpitis. The teeth were divided into three groups according to the pulp-capping agents: (I) hard-setting calcium hydroxide (Dycal) (control group) (n = 36), (II) bioactive tricalcium silicate (Biodentine) (n = 37), and (III) resin-based tricalcium silicate (TheraCal LC) (n = 36). All the teeth were evaluated clinically and radiographically at 6, 12, 18, and 24 months postoperatively. A total of 23 primary mandibular second molars that were in their regular exfoliation period (24-40 months) were extracted and fixed in 10% formaldehyde solution. The specimens were evaluated histologically to assess the integrity of the odontoblastic layer, tertiary dentin formation quality of the dentin formed, severity of pulpitis, and other pulpal changes. Data were analyzed using Fisher's exact test, Pearson's chi-square test, and McNemar's test (p = 0.05). RESULTS: At the end of the 24-month follow-up period, the clinical and radiographic success rates for Dycal, Biodentine, and TheraCal LC were 100%, 100%, and 93.3%, respectively, and there was no significant difference among the groups (p > 0.05). However, the TheraCal LC group was statistically unsuccessful when compared to the other groups with regard to the integrity of the odontoblastic layer, severity of pulpitis, and other pulpal changes in histological examination (p < 0.05). CONCLUSION: Indirect pulp capping exhibited high clinical and radiographic success rates in the treatment of primary teeth regardless of the chosen pulp-capping agent. However, histological examination indicated that the pulp status was affected by the chosen capping material especially when selecting a resin-containing material such as TheraCal LC. CLINICAL RELEVANCE: Resin-free calcium silicate-based materials appear to be more favorable in the indirect pulp treatment of primary teeth, particularly in young-age groups that require long-term success.

Odontoblast markers and dentine reactions in carious primary molars with and without hypomineralised enamel defects.

BACKGROUND: Wnt/ß-Catenin signalling and DMP1 have key roles in tertiary dentinogenesis. AIM: To compare the relationship between remaining dentine thickness (RDT), tertiary dentine thickness (TDT), ß-catenin and dentine matrix protein 1 (DMP1) in carious second primary molar teeth with normal (SPM) and hypomineralised enamel (HSPM). DESIGN: Extracted carious SPM and HSPM were fixed, sectioned (5 µm) and stained with haematoxylin and eosin or with indirect immunofluorescence for ß-catenin and DMP1. Image analysis was performed to determine RDT, TDT, ß-catenin and DMP1 intensity in the odontoblast layer and dentine-pulp complex. RESULTS: Carious SPM (n = 11; mean RDT = 1536.1 µm) and HSPM (n = 12; mean RDT = 1179.9 µm) had mean TDT 248.6 µm and 518.1 µm, respectively (P = .02). There were no significant differences in intensity values in the odontoblast layer and dentine-pulp complex for ß-catenin and DMP1 for both groups. CONCLUSION: There was no observable variation in Wnt/ß-catenin and DMP1 expression between HSPM and SPM despite a statistically significant twofold increased TDT in HSPM compared with SPM that had similar RDT. Thus, the observed increased TDT in HSPM is more likely due to an earlier onset of repair processes rather than an amplified response to caries.

The Effect of Calcium-Silicate Cements on Reparative Dentinogenesis Following Direct Pulp Capping on Animal Models.

Dental pulp vitality is a desideratum for preserving the health and functionality of the tooth. In certain clinical situations that lead to pulp exposure, bioactive agents are used in direct pulp-capping procedures to stimulate the dentin-pulp complex and activate reparative dentinogenesis. Hydraulic calcium-silicate cements, derived from Portland cement, can induce the formation of a new dentin bridge at the interface between the biomaterial and the dental pulp. Odontoblasts are molecularly activated, and, if necessary, undifferentiated stem cells in the dental pulp can differentiate into odontoblasts. An extensive review of literature was conducted on MedLine/PubMed database to evaluate the histological outcomes of direct pulp capping with hydraulic calcium-silicate cements performed on animal models. Overall, irrespective of their physico-chemical properties and the molecular mechanisms involved in pulp healing, the effects of cements on tertiary dentin formation and pulp vitality preservation were positive. Histological examinations showed different degrees of dental pulp inflammatory response and complete/incomplete dentin bridge formation during the pulp healing process at different follow-up periods. Calcium silicate materials have the ability to induce reparative dentinogenesis when applied over exposed pulps, with different behaviors, as related to the animal model used, pulpal inflammatory responses, and quality of dentin bridges.

MODERN ASPECTS OF TRAUMATIC PULPITIS TREATMENT WITH THE USE OF BIOCERAMICS.

OBJECTIVE: The aim: The research was to evaluate the effectiveness of acute traumatic pulpitis treatment with the use of bioceramics according to the results of a clinical study. PATIENTS AND METHODS: Materials and methods: Acute traumatic pulpitis of 25 teeth in 25 patients aged 18-25 years were treated by biological direct pulp capping. In 13 patients of the main group, bioceramics was placed on the exposed pulp, and in 12 patients of the control group, calcium hydroxide paste was applied on the exposed pulp. Treatment effectiveness was evaluated according to the following criteria: the absence of clinical signs of pulpal inflammation, on X-ray - signs of dentinal bridge formation, the absence of periapical changes. RESULTS: Results: The use of bioceramic material in patients of the main group provided a positive dynamic of treatment in 12 teeth. The need for re-treatment was diagnosed only in 1 clinical case (7.7%), in the control group - in 4 cases (33.3%). CONCLUSION: Conclusions: Pulpitis treatment with the use of bioceramics provides preserving the functional properties of pulp, creation of a calcified barrier - dentin bridge and prevents the periodontal complications compared to the pulp capping with a material based on calcium hydroxide. The effectiveness of treatment in the main group was 92.3%, in the control - 66.7%.

[Rationale for the use of bioactive cements by in vitro simulation of accidental pulp opening]. / Obosnovanie primeneniya bioaktivnykh tsementov dlya sokhraneniya zhiznesposobnosti pul'py pri ee sluchainom vskrytii.

OBJECTIVE: To study the features of reparative dentinogenesis when using biomaterials during accidental opening of the pulp in an experiment. MATERIAL AND METHODS: In an experiment on 3 dwarf pigs of the Svetlogorsk breed a traumatic opening of the tooth cavity was carried out in 18 teeth (6 molars, 6 premolars, 6 incisors), then Biodentin (9 teeth) and Aurosil (9 teeth) were applied on the opened pulp horn. After 14, 30 and 60 days, dwarf pigs were euthanized, and jaw blocks taken. Histological examination of the teeth was carried out using the method of embedding in methyl methacrylate (OsteoBead, Sigma, USA). Thin sections of 35-50 microns were made from the samples and stained using the «Heavenly Trichrome¼ method. Documentation was carried out using a Leica DM100 microscope and an EC3 digital camera in reflected and transmitted light. RESULTS: Histological examination of the thin sections of teeth stained according to the «Heavenly Trichrome¼ method revealed that 2 weeks after the pulp opening and applying of Aurosil and Biodentin, comparable processes occurred in the tooth cavity. Thus, the proliferation of odontoblasts was noted on the lateral surfaces of the chamber. New dentin layers and odontoblasts spread over the lower surface of the material with the formation of dentinal bridges by 4 weeks of observation in both groups. By week 12, there was a decrease in the proliferative activity of odontoblasts and dentin maturation in all cases. At the initial stages of the experiment, some pulp edema and moderate plethora were noted, which was no longer observed at 4 weeks. By 12 weeks, because of the proliferation of odontoblasts, the volume of the tooth cavity was reduced by a third. By the 6th month in the experiment, no significant changes in the structure of dentin and pulp were revealed. CONCLUSION: According to morphological data the studied biomaterials (Aurosil and Biodentin) contribute to dentin regeneration equally.

Age estimation of fragmented human dental remains by secondary dentin virtual analysis.

Unlike bones, teeth are remarkably resilient and can withstand severe trauma, making age assessment based on the dentition essential for forensic analysis. Modern techniques for age estimation focus on pulp-chamber volume measurements using radiographs and computerized tomography (CT); however, these are applicable only for complete teeth (i.e., with intact crown and root). In the current study, we developed a new approach using high-resolution micro-computerized tomography (µCT) to visualize the secondary dentin (SD), an inner layer surrounding the pulp which accumulates with age, thus facilitating age estimation of fragmented and broken teeth.The growth pattern of the SD with age was analyzed for 77 lower premolars from two anthropological collections. A comparison of SD virtual segmentation and histological measurement was highly correlative (ICC = 0.95). SD was measured per volume (mm3) of a 1 mm thick slice directly below the cemento-enamel junction. Regression analysis using SD measurements increased the success rates of age estimation (82%) compared with the "gold-standard" pulp/dentin method (54%) in the range of ± 10 years. The accuracy of age estimation based on SD analysis was improved to a range of 7-8 years.The SD method thus allows age estimation with greater prediction rates and better accuracy based on only a small fragment of a tooth in a non-invasive manner. This novel methodology is easy to use, accessible, and bears implications in various fields such as forensic sciences and anthropological research.