The effects of re-irradiation on the chemical and morphological properties of permanent teeth.

This study aimed to assess the in vitro effects of re-irradiation on enamel and dentin properties, simulating head and neck cancer radiotherapy retreatment. Forty-five human permanent molars were classified into five groups: non-irradiated; irradiated 60 Gy, and re-irradiated with doses of 30, 40, and 50 Gy. Raman spectroscopy, scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS) were employed for analysis. Raman spectroscopy assessed intensity, spectral area, and specific peaks comparatively. Statistical analysis involved Kolmogorov-Smirnov and One-Way ANOVA tests, with Tukey's post-test (significance level set at 5%). Significant changes in irradiated, non-irradiated, and re-irradiated enamel peaks were observed, including phosphate (438 nm), hydroxyapatite (582 nm), phosphate (960 nm), and carbonate (1070 nm) (p < 0.05). Re-irradiation affected the entire tooth (p > 0.05), leading to interprismatic region degradation, enamel prism destruction, and hydroxyapatite crystal damage. Dentin exhibited tubule obliteration, crack formation, and progressive collagen fiber fragmentation. EDX revealed increased oxygen percentage and decreased phosphorus and calcium post-reirradiation. It is concluded that chemical and morphological changes in irradiated permanent teeth were dose-dependent, exacerbated by re-irradiation, causing substantial damage in enamel and dentin.

Optical coherence tomography and gray scale digital analysis as noninvasive techniques for evaluating molar-incisor hypomineralization severity: A comparative study with microcomputed tomography.

Molar-incisor hypomineralization (MIH) is a qualitative defect of dental enamel characterized by demarcated opacities present in permanent first molars and other teeth. It is considered a major clinical challenge in dentistry because it makes affected teeth more susceptible to fractures and dental caries. Its diagnosis is mainly clinical and there are few technological resources that allow for a more accurate diagnosis, especially with respect to the depth of the defect in the dental enamel. In this context, optical coherence tomography (OCT), which is routinely used in ophthalmology, can produce images of the depth of the dental enamel, making it a promising method. In this study, 33 teeth with different MIH severities were evaluated using OCT and microcomputed tomography (microCT). Semi-quantitative methods of grayscale pattern analysis were used to compare images obtained from different severities of MIH with the mineral density obtained through microCT. MicroCT evaluation revealed that hypomineralized enamel had a significantly lower mineral density than intact enamel. However, this difference was not observed between the mild and severe MIH lesions. In the OCT evaluation, significant differences were observed between the intact and hypomineralized enamel, and the gray value comparison provided a method for quantitative differentiation between the two. This study suggests that OCT could be a useful adjunct to traditional diagnostic methods for MIH, offering a noninvasive approach to evaluate enamel defects. RESEARCH HIGHLIGHTS: Combining optical coherence tomography with grayscale digital analysis shows potential as a promising method for diagnosing molar-incisor hypomineralization and assessing its level of severity.

Analysis of the cytotoxicity and bioactivity of CeraSeal, BioRoot™ and AH Plus® sealers in pre-osteoblast lineage cells.

BACKGROUND: The objective of the present study was to evaluate in vitro the cytotoxicity and bioactivity of various endodontic sealers (CeraSeal, BioRoot™ and AH Plus®) in pre-osteoblast mouse cells (MC3T3 cells). METHODS: MC3T3 cells (ATCC CRL-2594) were plated in 1 × 104 cells/well in 96-well plates in contact with endodontic sealers at concentrations of 1:10 and 1:100. Cell viability was evaluated by MTT assay after 24 and 48 h. In addition, sealer bioactivity was measured by RT-PCR for mediator of inflammation (Tnf, Ptgs2) and mineralization (Runx2, Msx1, Ssp1 and Dmp1) after 24 h and by Alizarin Red S Assay of mineralization after 28 days. Data were analyzed using one-way ANOVA followed by the Tukey's post-test at a significance level of 5%. RESULTS: BioRoot™ presented 24-hour cytotoxicity (p < 0.05) at 1:10 concentration. In the period of 48 h, no endodontic cement was cytotoxic to the cells compared to the control (p > 0.05). TNF-α gene expression was induced by AH Plus® (p < 0.05), while Ptgs2 was induced by the CeraSeal and BioRoot™ (p < 0.05). The expression of Runx2 was stimulated by BioRoot™ and AH Plus® (p < 0.05). In contrast, the expression of Dmp-1 Dmp1 was higher for the CeraSeal and BioRoot™ (p < 0.05). Nonetheless, the sealers did not impact the formation of mineralization nodules (p > 0.05). CONCLUSION: CeraSeal, BioRoot™ and AH Plus® sealers were not cytotoxic to MC3T3 cells within 48 h, but differentially induced the expression of genes related to inflammation and mineralization without impacting biomineralization by the cells.

Activation of gelatinases in permanent human teeth after different experimental radiotherapy protocols.

The objective of this study was to compare the activation of gelatinases in dentin-enamel junction (DEJ) and underlying dentin of permanent teeth after experimental radiotherapy in conventional and hypofractionated modalities. Newly extracted third molars (n = 15) were divided into three experimental radiotherapy groups: control, conventional (CR), and hypofractionated (HR) (n = 5 per group). After in vitro exposure to ionizing radiation, following standardized protocols for each modality, a gelatinous substrate was incubated on the tooth slices (n = 10 per group). Activation of gelatinases was measured by in situ zymography, expressed in arbitrary fluorescence units (mm2) from three tooth regions: cervical, cuspal, and pit. Fluorescence intensity was compared among radiotherapy protocols and tooth regions in each protocol, considering a significance level of 5%. Considering all tooth regions, the fluorescence intensity of the CR group was higher than the HR and control groups, both in DEJ and underlying dentin (p <0.001). In addition, the fluorescence intensity was higher in underlying dentin when compared to DEJ in all groups (p <0.001). Considering each tooth region, a statistically significant difference between CR and HR was only observed in the pit region of underlying dentin (p <0.001). Significant and positive correlations between fluorescence intensities in DEJ and underlying dentin were also observed (p <0.001). Experimental radiotherapy influenced the activation of gelatinases, as well as exposure to the conventional protocol can trigger a higher activation of gelatinases when compared to hypofractionated, both in DEJ and underlying dentin.

Use of Optical Coherence Tomography for Differential Diagnosis of Severity of Molar Incisor Hypomineralization (MIH).

Purpose: To evaluate descriptively and quantitatively teeth affected by enamel hypomineralization (EH) using optical coherence microtomography (OCT). Methods: Twenty teeth were classified according to the European Academy of Pediatric Dentistry's molar incisor hypomineralization (MIH) index and separated into groups according to the degree of EH severity. For each tooth, scans were performed on both the affected and the non-affected areas, and their corresponding optical images were captured. Results: In the qualitative analyses, in most of the images bright lines were observed in relation to the enamel surface and a high level of photon scattering immediately below the enamel surface. This showed that the shading distribution can be identified as hypomineralized areas in which the scattering signal can be used as a diagnostic criterion. In the quantitative analyses, Tukey's test was performed to evaluate the means of the optical attenuation coefficient, which did not present significant differences. However, considering the correlation, homogeneity and contrast analyses, a statistically significant difference was observed between the groups. The group with severe MIH showed greater homogeneity and correlation, but less contrast. Conclusion: Currently, MIH has its severity measured by essentially clinical means. OCT processing techniques reveal advances in the diagnostic imaging of MIH, showing that image texture analysis can be a promising and useful method to aid in its diagnosis.

Comparison between intraoral scanning and direct visual analysis for the assessment of developmental defects of enamel.

OBJECTIVE: To compare direct visual analysis (DVA) and intraoral scanning (IOS) for the assessment of developmental defects of the enamel (DDE). METHODS: Thirty-nine extracted permanent human teeth with DDE were selected by an experienced examiner and digitised using IOS. The scanning was recorded using the OBS Studio software parallel to the IOS software to obtain a coloured high-definition MP4 file of the process. Two other experienced, blinded, and calibrated examiners randomly analysed the same teeth through DVA and IOS. A third examiner resolved any disagreements between the two examiners. Descriptive statistics were used to analyse the frequencies of the scores. Cohen's kappa test was used to determine whether the DVA scores were different from those assigned using IOS. Spearman's test was used to verify non-random examiner errors. The Chi-square test was used to compare score frequencies. Statistical significance was set at p <0.05. RESULTS: Scores indicating more severe and extended DDE (p <0.05) were more frequently assigned with IOS than with DVA (IOS: 25.64%, 25.64%, 38.46%, and 35.90% between one-third to two-third of the lingual, occlusal, mesial, and distal surfaces, respectively; vs. DVA: 10.26%, 7.69%, 15.38%, and 10.26% for the respective aforementioned tooth surfaces). Contrarily, 'no visible enamel defect' was significantly less assigned for IOS than for DVA (IOS: 15.38%, 43.59%, 35.90%, 15.38%, and 17.95% for buccal, lingual, occlusal, mesial, and distal surfaces, respectively; vs. DVA: 38.46%, 66.67%, 56.41%, 51.28%, and 43.59% for the respective aforementioned tooth surfaces). Kappa agreement ranged from fair to moderate when comparing DVA and IOS; the correlation between both methods was positive, indicating that the examiners assigned the scores properly and the differences arose from employing different methods. CONCLUSION: The assessment of DDE differed depending on the method used. IOS scores indicated more severe and extended DDE than DVA scores. Clinical investigation is the next step in validating the use of IOS for DDE diagnosis. CLINICAL SIGNIFICANCE: This study showed that DDE can be assessed differently using IOS. It is clinically relevant as it directly affects the determination of the severity of the defect and dental treatment planning.

Reparative Dentin Formation Following Dental Pulp Capping is Mediated by TNFR1 In Vivo.

INTRODUCTION: Tumor necrosis factor (TNF)-α is a pro-inflammatory cytokine that promotes biomineralization in vitro in dental pulp cells. However, the role of TNF-α-TNF receptor 1 (TNFR1) signaling in reparative dentin formation and related inflammatory pathways is not known. Therefore, the aim of this study was to evaluate the role of the TNF-α-TNFR1 axis in dental pulp repair following pulp capping in vivo. METHODS: Dental pulp repair response of genetically deficient TNF-α receptor-1 mice (TNFR1-/-; n = 20) was compared with that of C57Bl6 mice (wild type [WT]; n = 20). Pulp capping was performed with mineral trioxide aggregate on the mandibular first molars of mice. After 7 and 70 days, tissues were collected and stained with hematoxylin and eosin for histopathological and histometric evaluation, and assessed by the Brown and Brenn methods for histomicrobiological analysis and by immunohistochemistry to localize TNF-α, Runt-related transcription factor 2, Dentin Sialoprotein (DSP) and Osteopontin (OPN) expression. RESULTS: Compared with WT mice, TNFR1-/- mice showed significantly decreased reparative dentin formation with a lower mineralized tissue area (P < .0001). Unlike WT mice, TNFR1-/- mice also exhibited significant dental pulp necrosis, neutrophil recruitment, and apical periodontitis formation (P < .0001) without bacterial tissue invasion. TNFR1-/- animals further exhibited decreased TNF-α, DSP, and OPN expression (P < .0001), whereas Runt-related transcription factor 2 expression was unchanged (P > .05). CONCLUSION: The TNF-α-TNFR1 axis is involved in reparative dentin formation following dental pulp capping in vivo. Genetic ablation of TNFR1 modified the inflammatory process and inhibited the expression of the DSP and OPN mineralization proteins, which culminated in dental pulp necrosis and development of apical periodontitis.

TNF-α-TNFR1 Signaling Mediates Inflammation and Bone Resorption in Apical Periodontitis.

INTRODUCTION: The aim of this study was to investigate the role of the proinflammatory axis TNF-α-TNFR1 in experimentally induced periapical inflammation and bone resorption in mice. METHODS: After receiving Ethics Committee Approval (2019.1.139.58.0), experimental apical periodontitis was induced by means of inoculating oral microorganisms into the root canals of molars of mice. Genetically deficient tumor necrosis factor-α receptor-1 mice (TNFR1-/-; n = 50) response was compared with that of C57Bl6 wild-type mice (wild-type; n = 50) after 7, 14, 28, and 42 days. The analyses performed were micro-computed tomographic, histopathologic, histomicrobiological, and histometric evaluation, tartrate-resistant acid phosphatase staining, immunohistochemistry, and quantitative reverse transcriptase polymerase chain reaction. Data were analyzed by using one-way analysis of variance, followed by Tukey or Bonferroni tests (α = 5%). RESULTS: TNFR1-/- mice exhibited lower recruitment of neutrophils at 14, 28, and 42 days (P < .05), which resulted in reduced area and volume of apical periodontitis at 42 days (P < .05). The number of osteoclasts was also lower in TNFR1-/- animals at 14 and 42 days (P < .01), along with reduced synthesis of CTSK, MMP-9, and COX-2. Expression of RANKL, but not OPG, was reduced at 14 and 42 days (P < .001). The highest RANKL expression over OPG (ratio > 1) was found in wild-type animals at 7 (P < .0001) and 42 days (P < .001). CONCLUSIONS: Periapical inflammation and bone resorption were exacerbated in wild-type animals compared with TNFR1-/- mice, demonstrating that the TNF-α-TNFR1 signaling pathway mediated catabolic events in bone after root canal contamination.

Detection of Apical Dental Resorption Caused by Endodontic Infection in Mice Using Fluorescence and Bright-Field Microscopy.

The aim of this study was to evaluate the sensitivity, specificity, and predictive values of the fluorescence microscopy method in the detection of apical dental reabsorption after induction of apical periodontitis in animal models. Forty-first molars of mice, aged 6 to 8 weeks, had their root canals exposed to the oral environment or were maintained healthy as controls (n = 20). After 14 and 42 days, mice were euthanized and tissues were collected for histological evaluation by means of bright field and fluorescence microscopy. The accuracy of fluorescence microscopy in identifying apical external dental resorption was investigated using a diagnostic validation test based on the sensitivity (S) and specificity (E) properties. Bright-field microscopy revealed a higher number of specimens with scores of 1 to 3 - absence of apical dental resorption (n = 29; 52%), while fluorescence microscopy revealed a higher number of specimens with scores of 4 to 6 - presence of apical dental resorption (n = 37; 66%). Out of 56 specimens, 26 were TP, 11 were FP, and 19 were TN. No FN result was observed. Fluorescence microscopy presented a sensitivity value of 1, similar to the bright-field method, while specificity was lower (0.633). The accuracy of the fluorescent method to detect apical dental resorption was 0.804. Fluorescence microscopy revealed a higher number of false positive apical dental resorption than bright-field microscopy. The detection of apical dental resorption was not impacted by the sensitivity of the method but by its specificity.

Electromyographic analysis of the stomatognathic system of children with Molar-incisor hypomineralization.

INTRODUCTION: Molar-incisor hypomineralization (MIH) is a qualitative defect of dental enamel that affects one or more permanent first molars, with or without involvement of the incisor teeth. This condition leads to challenges to dental care and treatment planning. AIM: Based on the hypothesis that children who have MIH possibly present alterations in postural and masticatory activities and considering the absence of studies investigating these parameters, the present study evaluated the functionality of the stomatognathic system considering the mentioned aspects. MATERIALS: The comparison of individuals with (MIHG; n = 32) and without MIH (CG; n = 32) was evaluated by electromyographic activity of the masseter and temporal muscles (right and left), as well as evaluation of the masticatory cycles during habitual mastication. RESULTS: MIHG showed muscle hyperactivity in postural and dynamic conditions compared to the CG; higher electromyographic values for MIHG when compared to CG in the following postural conditions: at rest for the right temporal (p = 0.00) and left temporal muscles (p = 0.03); in the protrusion to the right temporal muscle (p = 0.02); in the right laterality for the right masseter (p = 0.00) and left temporal muscles (p = 0.01); in the left laterality for the right masseter (p = 0.03) and left temporal (p = 0.04) muscles. In dynamic conditions with consistent food, significance was observed for the left temporal (p = 0.01); and with soft food for the right (p = 0.01) and left temporal muscles (p = 0.04). CONCLUSIONS: Children with MIH seem to have impaired functionality of the stomatognathic system. Children with MIH have alterations in the stomatognathic system.

Systemic inhibition of 5-lipoxygenase by MK-886 exacerbates apical periodontitis bone loss in a mouse model.

BACKGROUND: To investigate if 5-LO selective inhibitor (MK-886) could be used for systemic treatment of experimentally induced apical periodontitis in a mouse model. METHODS: Twenty-four C57BL/6 mice were used. After coronal opening, a solution containing Escherichia coli LPS (1.0 µg/µL) was inoculated into the root canals of the lower and upper right first molars (n = 72 teeth). After 30 days apical periodontitis was established, and the animals were treated with MK-886 (5 mg/kg), a 5-LO inhibitor, for 7 and 14 days. The tissues were removed for histopathological and histometric analyses, evaluation of osteoclast number and gene expression for receptor activator of nuclear factor kappa-B (Tnfrsf11a), receptor activator of nuclear factor kappa-B ligand (Tnfsf11), osteoprotegerin (Tnfrsf11b), tartrate-resistant acid phosphatase (Acp5), matrix metalloproteinase-9 (Mmp9), cathepsin K (Ctsk) and calcitonin receptor (Calcr). Statistical data analysis was performed using Kruskal Wallis followed by Dunn's tests (α = 0.05). RESULTS: Administration of MK-886 for 7 days exerted no effect on apical periodontitis progression compared to LPS inoculation without treatment (p = 0.3549), while treatment for 14 days exacerbated bone loss (p < 0.0001). Administration of MK-886 enhanced osteoclastogenesis signaling and osteoclast formation within 7 days (p = 0.0005), but exerted no effect at 14 days (p > 0.9999). After 7 days of treatment, MK-886 induced mRNA expression for Acp5 (p = 0.0001), Calcr (p = 0.0003), Mmp9 (p = 0.0005) and Ctsk (p = 0.0008), however no effect in those gene expression was observed after 14 days (p > 0.05). CONCLUSION: Systemic treatment with MK-886 exacerbated LPS-induced apical periodontitis in a mouse model.

Genetic polymorphism in the tumour necrosis factor alpha gene (G-308A) is associated with persistent apical periodontitis in Brazilians.

AIM: To investigate if there was an association between genetic polymorphisms in tumour necrosis factor (TNF)-⍺ and its receptors TNFRSF1A and TNFRSF1B with persistent apical periodontitis (PAP) in Brazilian subjects. METHODOLOGY: Patients who had pulpal necrosis and apical periodontitis at the time of treatment, with at least 1-year of follow-up after non-surgical root canal treatment were recalled. Three hundred and seventy eight subjects were included, 150 subjects with signs/symptoms of PAP and 228 subjects with root canal-treated teeth exhibiting healthy perirradicular tissues (healed). Genomic DNA was extracted from saliva and used for TNF-⍺ (rs1800629), TNFRSF1A (rs1800693) and TNFRSF1B (rs1061622) genotyping by real-time PCR. Genotypes and alleles frequencies were evaluated by c2 or Fisher's exact tests and odds ratios were implemented (α = 5%). RESULTS: The genetic polymorphism in TNF-α (rs1800629) was associated as a protective factor for the development of PAP (p < .05), once subjects who presented at least one allele A (AA+AG X GG), had a higher chance to lesion repair (p < .05). The polymorphisms rs1800693 and rs1061622 in TNF receptors (TNFRSF1A and TNFRSF1B, respectively) were not associated with the development of PAP (p > .05). CONCLUSIONS: The observed results demonstrate that polymorphism in TNF-α but not in its receptors is associated with PAP.

Randomized Clinical Study of the Use of MTA and Biodentine™ for Pulpotomy in Primary Teeth

ABSTRACT Objective: To verify, through clinical and radiographic evaluations, the in vivo response of the dentin-pulpal complex of human primary teeth after pulpotomy with MTA and Biodentine™ in a follow-up period of 3, 6, and 12 months. Material and Methods: Thirty teeth were divided into MTA pulpotomy (n = 15) and Biodentine™ pulpotomy (n = 15) from children between 5 and 9 years of age, a randomized clinical trial with simple random sampling. The materials were inserted into the cavity after opening and removing the coronary pulp tissue. The cavity base consisted of glass ionomer cement and light-cured composite resin restoration. Clinical and radiographic analyses were performed after 3, 6, and 12 months. Statistical analysis by Fisher's exact test for dichotomous data at a 5% significance level was utilized. Results: Both materials caused color change after 12 months. However, MTA showed a higher percentage than Biodentine™ (p<0.0001). Pain was detected only with Biodentine™ at six months and mobility at 12 months (p=0.0013). Radiographically, after 12 months, periapical lesions, interradicular lesions, and internal resorption were evidenced in 13% of the cases for Biodentine™-treated teeth (p<0.0013). MTA induced pulp calcification in 13% of cases, unlike Biodentine™ (p<0.0013). Conclusion: BiodentineTM and MTA are suitable for clinical use in pulpotomy treatment, yet both materials lead to tooth discoloration.

Activation of gelatinases in permanent human teeth after different experimental radiotherapy protocols

Abstract The objective of this study was to compare the activation of gelatinases in dentin-enamel junction (DEJ) and underlying dentin of permanent teeth after experimental radiotherapy in conventional and hypofractionated modalities. Newly extracted third molars (n = 15) were divided into three experimental radiotherapy groups: control, conventional (CR), and hypofractionated (HR) (n = 5 per group). After in vitro exposure to ionizing radiation, following standardized protocols for each modality, a gelatinous substrate was incubated on the tooth slices (n = 10 per group). Activation of gelatinases was measured by in situ zymography, expressed in arbitrary fluorescence units (mm2) from three tooth regions: cervical, cuspal, and pit. Fluorescence intensity was compared among radiotherapy protocols and tooth regions in each protocol, considering a significance level of 5%. Considering all tooth regions, the fluorescence intensity of the CR group was higher than the HR and control groups, both in DEJ and underlying dentin (p <0.001). In addition, the fluorescence intensity was higher in underlying dentin when compared to DEJ in all groups (p <0.001). Considering each tooth region, a statistically significant difference between CR and HR was only observed in the pit region of underlying dentin (p <0.001). Significant and positive correlations between fluorescence intensities in DEJ and underlying dentin were also observed (p <0.001). Experimental radiotherapy influenced the activation of gelatinases, as well as exposure to the conventional protocol can trigger a higher activation of gelatinases when compared to hypofractionated, both in DEJ and underlying dentin.

Resumo O objetivo deste estudo foi comparar a ativação de gelatinases na junção dentina-esmalte (DEJ) e na dentina subjacente de dentes permanentes após a radioterapia experimental nas modalidades convencional e hipofracionada. Os terceiros molares recém-extraídos (n = 15) foram divididos em três grupos de radioterapia experimental: controle, convencional (CR) e hipofracionada (HR) (n = 5 por grupo). Após a exposição in vitro à radiação ionizante, seguindo protocolos padronizados para cada modalidade, um substrato gelatinoso foi incubado nas fatias de dente (n = 10 por grupo). A ativação das gelatinases foi medida por zimografia in situ, expressa em unidades arbitrárias de fluorescência (mm2) de três regiões do dente: cervical, cúspide e fossa. A intensidade da fluorescência foi comparada entre os protocolos de radioterapia e as regiões do dente em cada protocolo, considerando um nível de significância de 5%. Considerando todas as regiões do dente, a intensidade de fluorescência do grupo CR foi maior do que a dos grupos HR e controle, tanto no DEJ quanto na dentina subjacente (p <0,001). Além disso, a intensidade da fluorescência foi maior na dentina subjacente quando comparada à DEJ em todos os grupos (p <0,001). Considerando cada região do dente, uma diferença estatisticamente significativa entre CR e HR foi observada apenas na região da fossa da dentina subjacente (p <0,001). Também foram observadas correlações significativas e positivas entre as intensidades de fluorescência no DEJ e na dentina subjacente (p <0,001). A radioterapia experimental influenciou a ativação das gelatinases, assim como a exposição ao protocolo convencional pode desencadear uma maior ativação das gelatinases quando comparada ao hipofracionamento, tanto no DEJ quanto na dentina subjacente.

Use of Images and Clinical Experience to Calibrate Dental Surgeons for the Diagnosis of Molar Incisor Hypomineralization

ABSTRACT Objective: To evaluate an imaging protocol for use as a diagnostic and calibration tool for dentists before and after practical activity. Material and Methods: Thirty photos of children's teeth with or without changes in dental enamel were selected and evaluated by a group of experienced dentists previously calibrated to establish the diagnosis defined as the gold standard. After instructions, the images were shown to a group of postgraduate dentists for free identification of dental changes. Subsequently, a lecture on molar incisor hypomineralization (MIH) was carried out, and, at 14 days and all calibration was performed using the criteria previously. The retest was performed at 28 days. After experience in clinical activity in the following two weeks, the post-test was performed at 49 days. Data were analyzed using Cohen's kappa coefficient. Results: Theoretical learning on the subject showed low inter-examiner agreement when the diagnosis of defects was made from images obtained from intraoral photographs. After clinical practice, there was greater intra-examiner agreement. After theoretical training, dentists started to identify different types of enamel alteration, although with low agreement between them. Conclusion: Clinical experience in theoretical and imaging training favored the identification of defects. However, it is necessary to improve the protocol to establish a reliable and viable diagnostic method for calibration in MIH.

Use of Restorative Materials in Primary Teeth - A Retrospective University-Based Study

ABSTRACT Objective: To investigate the types of restorative materials used for restorative treatment in primary teeth through a retrospective university-based study. Material and Methods: The sample consisted of all clinical records of children attended at the Pediatric Dentistry Clinic at the School of Dentistry of Ribeirão Preto at the University of São Paulo in Brazil. Inclusion criteria were primary anterior and posterior teeth that received dental restorations for treatment of dental caries lesions, dental trauma or dental development defects from 2013 to 2018. Restoration repairs and interim restorations during this period were also recorded. Descriptive analyzes were performed to assess the distribution according to the type of restorative material used over the years. Results: A total of 5,236 restorative procedures were performed in primary teeth, including restoration repair and interim restorations. Of those, 69% were done in posterior teeth and 31% in anterior teeth. Sixty percent of the procedures performed during this period were made of composite resin and a lower percentage of glass ionomer cement (18%) followed by silver amalgam (1%). The number of interim restorations was smaller but proportional to those of composite resin over the years. Conclusion: A tendency to carry out restorative treatment of primary teeth with composite resin during the 6 years of follow-up was observed.

Leukotriene B4 Loaded in Microspheres Inhibits Osteoclast Differentiation and Activation.

To investigate osteoclast formation in vivo and if leukotriene B4 (LTB4) loaded in microspheres (MS) could be used as a therapeutical strategy to promote a sustained delivery of the mediator and prevent osteoclast differentiation. Methods: In vivo, apical periodontitis was induced in mice to investigate osteoclast differentiation and signaling in absence of 5-lipoxygenase (5-LO). In vitro, LTB4-MS were prepared using an oil-in-water emulsion solvent extraction-evaporation process. Characterization and efficiency of LTB4 encapsulation were investigated. J774A.1 macrophages were cultured in the presence of monocyte colony-stimulating factor (M-CSF) and ligand for receptor activator of nuclear factor kappa B (RANKL) and then stimulated with LTB4-MS. Cytotoxicity, in vitro MS-LTB4 uptake, osteoclast formation and gene expression were measured. Results: We found that 5-LO negatively regulates osteoclastic formation in vivo during apical periodontitis development. In vitro, LTB4-MS were up-taken by macrophages and were not cytotoxic to the cells. LTB4-MS inhibited osteoclast formation and the synthesis of osteoclastogenic genes Acp5, Mmp9, Calcr and Ctsk. LTB4-MS inhibited differentiation of macrophages into an osteoclastic phenotype and cell activation under M-CSF and RANKL stimulus.

Leukotriene B4 Loaded in Microspheres Inhibits Osteoclast Differentiation and Activation

Abstract To investigate osteoclast formation in vivo and if leukotriene B4 (LTB4) loaded in microspheres (MS) could be used as a therapeutical strategy to promote a sustained delivery of the mediator and prevent osteoclast differentiation. Methods: In vivo, apical periodontitis was induced in mice to investigate osteoclast differentiation and signaling in absence of 5-lipoxygenase (5-LO). In vitro, LTB4-MS were prepared using an oil-in-water emulsion solvent extraction-evaporation process. Characterization and efficiency of LTB4 encapsulation were investigated. J774A.1 macrophages were cultured in the presence of monocyte colony-stimulating factor (M-CSF) and ligand for receptor activator of nuclear factor kappa B (RANKL) and then stimulated with LTB4-MS. Cytotoxicity, in vitro MS-LTB4 uptake, osteoclast formation and gene expression were measured. Results: We found that 5-LO negatively regulates osteoclastic formation in vivo during apical periodontitis development. In vitro, LTB4-MS were up-taken by macrophages and were not cytotoxic to the cells. LTB4-MS inhibited osteoclast formation and the synthesis of osteoclastogenic genes Acp5, Mmp9, Calcr and Ctsk. LTB4-MS inhibited differentiation of macrophages into an osteoclastic phenotype and cell activation under M-CSF and RANKL stimulus.

Resumo O objetivo deste trabalho foi Investigar a formação de osteoclastos in vivo e se o leucotrieno B4 (LTB4) incorporado em microesferas (MS) poderia ser usado como estratégia terapêutica para promover uma entrega sustentada do mediador e prevenir a diferenciação dos osteoclastos. Métodos: In vivo, a periodontite apical foi induzida em camundongos para investigar a diferenciação e sinalização de osteoclastos na ausência de 5-lipoxigenase (5-LO). In vitro, LTB4-MS foi preparado usando um processo de evaporação e extração de solvente de emulsão de óleo em água. A caracterização e a eficiência do encapsulamento do LTB4 foram investigadas. Macrófagos J774A.1 foram cultivados na presença de fator estimulador de colônia de monócitos (M-CSF) e ligante para o receptor ativador do fator nuclear kappa B (RANKL) e, então, estimulados com LTB4-MS. Citotoxicidade, captação in vitro de MS-LTB4, formação de osteoclastos e expressão gênica foram avaliadas. Resultados: A via 5-LO regula negativamente a formação de osteoclastos in vivo durante o desenvolvimento da periodontite apical. In vitro, LTB4-MS foram fagocitadas pelos macrófagos e não foram citotóxicos para as células. LTB4-MS inibiu a formação de osteoclastos e a síntese dos genes pró-osteoclastogênicos Acp5, Mmp9, Calcr e Ctsk. Conclusões: LTB4-MS inibiu a diferenciação de macrófagos em um fenótipo osteoclástico e a ativação celular sob estímulo de M-CSF e RANKL.

Enamel biomineralization under the effects of indomethacin and celecoxib non-steroidal anti-inflammatory drugs.

The aim of this study was to explore the effects of nonsteroidal anti-inflammatory drugs on biomineralization of enamel. Sixty C57Bl6 male mice were used, which were assigned into three groups: celecoxib (n = 20) or indomethacin (n = 20) treatment for a period of 28 days or received no medication (control group, n = 20). Visual inspection and microcomputed tomography were used to analyze enamel morphology. Scanning electron microscopy-Energy dispersive X-ray and Knoop microhardness test were used to quantify chemical element content (Ca, P, C, O) and enamel microhardness, respectively. Tissues were collected to investigate the synthesis, activity or nuclear translocation of metalloproteinase-20, transcription factor Runx2, dentin sialoprotein and cyclooxygenase-2 enzyme by means of immunohistochemistry, in situ zymography and indirect immunofluorescence. Treatment with indomethacin and celecoxib reduced the Ca and P content, microhardness and mineral density in enamel. Treatment with nonsteroidal anti-inflammatory drugs caused an accumulation of metalloproteinase-20 and overall increased enzymatic activity in enamel matrix, while the synthesis of the transcription factor Runx2 was inhibited by these drugs. Interestingly, indomethacin inhibited Runx2 translocation to the nucleus whereas celecoxib did not. Those findings show that non-steroidal anti-inflammatory drugs impact the enamel biomineralization and could be involved in the etiology tooth enamel defects if used during the period of tooth formation and mineralization.

Absence of Tumor Necrosis Factor Receptor 1 Inhibits Osteoclast Activity in Apical Dental Resorption Caused by Endodontic Infection in Mice.

INTRODUCTION: The aim of this study was to evaluate osteoclastogenesis and dental resorption resulting from endodontic infection in wild-type (WT) and tumor necrosis factor receptor 1 genetically deficient (TNFR1 KO) mice. METHODS: After approval by the ethics committee on the use of animals, 40 mice were distributed into 2 experimental groups based on time periods: 14 days (n = 10 WT mice and n = 10 TNFR1 KO mice) and 42 days (n = 10 WT mice and n = 10 TNFR1 KO mice). After these periods, morphometric analysis was performed using bright field and fluorescence microscopy and tartrate-resistant acid phosphatase histoenzymology to identify osteoclasts. One-way analysis of variance followed by the Tukey post hoc test was used for the statistical analysis (α = 0.05). RESULTS: WT mice in the 42-day period had a greater apical dental resorption in the distal root of the first molar than TNFR1 KO mice (P < .05). On the other hand, TNFR1 KO mice showed a smaller number of osteoclasts on the dental surface than WT mice (P < .05). CONCLUSIONS: WT mice with apical periodontitis had more extensive apical dental resorptions and a larger number of osteoclasts on the tooth surface than TNFR1 KO mice.