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.

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.

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.

Comparative Molecular Analysis of Gram-Negative Bacteria in Primary Teeth with Irreversible Pulpitis or Periapical Pathology.

Purpose: The purpose of this study was to compare the Gram-negative pathogens identified in the root canals of primary teeth with irreversible inflammatory pulpitis and in teeth showing apical periodontitis. Methods: Samples were collected from 123 root canals of primary teeth from three- to seven-year-old patients. Root canals were assigned to either group one (irreversible inflammatory pulpitis; n equals 63) or group two (pulp necrosis and apical periodontitis; n equals 60). Total number of cells of selected Gram-negative microorganisms was determined by the checkerboard DNA-DNA hybridization technique. Demographic data were compared using either chi-squared or t tests. Total numbers of microorganisms were compared using the Mann-Whitney test (α equals 0.05). Results: There were no significant intergroup differences in gender, age, and tooth group distribution (P>0.05). Among the 123 samples, 17 were discarded due to salivary contamination. The total numbers of Prevotella nigrescens, Treponema denticola, Fusobacterium nucleatum polymorphum, Fusobacterium nucleatum spp nucleatum, Aggregatibacter actinomycetemcomitans serotype a, Aggregatibacter actinomycetemcomitans serotype b, Porphyromonas gingivalis, Prevotella intermedia, and Prevotella melaninogenica were higher in teeth with apical periodontitis compared to those with irreversible inflammatory pulpitis (P<0.05). Conclusion: Higher numbers of Gram-negative bacteria were found in teeth with apical periodontitis compared to teeth with irreversible in- flammatory pulpitis.

Audiovisual distraction methods for anxiety in children during dental treatment: A systematic review and meta-analysis.

BACKGROUND: Dental treatment can cause symptoms such as fear and anxiety. Audiovisual distraction (AD) is a simple and low-cost technique that does not interfere with the dental treatment. AIM: The aim of this study was to perform a systematic review and meta-analysis to evaluate the effectiveness of AD methods for children who experience anxiety during dental treatment. MATERIALS AND METHODS: Two reviewers performed a database search of the studies published between January 1950 and November 2015. The inclusion criteria were papers published in the English language, child samples aged 4-10 years, and use of AD. All potentially relevant studies were identified by the title and the abstract. After the full-text analysis of the potentially relevant studies, the selected studies were included in the systematic review. A meta-analysis calculation was performed for the overall data and the subgroup data. RESULTS: Thirty-seven nonduplicated studies were found. However, after reviewing the articles, only five were included. A high variability was observed among the papers. Tools and questionnaires used to measure the anxiety during dental treatment presented the most common variability. Meta-analysis demonstrated a lower anxiety level in AD method groups when Modified Child Dental Anxiety Scale was used (P = 0.02) with a mean difference (confidence interval) of -8.72 (-16.7, -1.38). CONCLUSION: The AD method is effective for controlling dental anxiety in children.

Mucocele and fibroma: treatment and clinical features for differential diagnosis.

Mucocele is a benign lesion occurring in the buccal mucosa as a result of the rupture of a salivary gland duct and consequent outpouring of mucin into soft tissue. It is usually caused by a local trauma, although in many cases the etiology is uncertain. Mucocele is more commonly found in children and young adults, and the most frequent site is the lower inner portion of the lips. Fibroma, on the other hand, is a benign tumor of fibrous connective tissue that can be considered a reactionary connective tissue hyperplasia in response to trauma and irritation. They usually present hard consistency, are nodular and asymptomatic, with a similar color to the mucosa, sessile base, smooth surface, located in the buccal mucosa along the line of occlusion, tongue and lip mucosa. Conventional treatment for both lesions is conservative surgical excision. Recurrence rate is low for fibroma and high for oral mucoceles. This report presents a series of cases of mucocele and fibroma treated by surgical excision or enucleation and the respective follow-up routine in the dental clinic and discusses the features to be considered in order to distinguish these lesions from each other.

High matrix metalloproteinase activity is a hallmark of periapical granulomas.

INTRODUCTION: The inability to distinguish periapical cysts from granulomas before performing root canal treatment leads to uncertainty in treatment outcomes because cysts have lower healing rates. Searching for differential expression of molecules within cysts or granulomas could provide information with regard to the identity of the lesion or suggest mechanistic differences that may form the basis for future therapeutic intervention. Thus, we investigated whether granulomas and cysts exhibit differential expression of extracellular matrix (ECM) molecules. METHODS: Human periapical granulomas, periapical cysts, and healthy periodontal ligament tissues were used to investigate the differential expression of ECM molecules by microarray analysis. Because matrix metalloproteinases (MMP) showed the highest differential expression in the microarray analysis, MMPs were further examined by in situ zymography and immunohistochemistry. Data were analyzed by using one-way analysis of variance followed by the Tukey test. RESULTS: We observed that cysts and granulomas differentially expressed several ECM molecules, especially those from the MMP family. Compared with cysts, granulomas exhibited higher MMP enzymatic activity in areas stained for MMP-9. These areas were composed of polymorphonuclear cells (PMNs) in contrast to cysts. Similarly, MMP-13 was expressed by a greater number of cells in granulomas compared with cysts. CONCLUSION: Our findings indicate that high enzymatic MMP activity in PMNs together with MMP-9 and MMP-13 stained cells could be a molecular signature of granulomas unlike periapical cysts.

Cone-beam computerized tomographic, radiographic, and histologic evaluation of periapical repair in dogs' post-endodontic treatment.

OBJECTIVE: To evaluate the periapical repair after root canal treatment in the teeth of dogs using CT and conventional radiography and to compare these findings with the gold standard microscopic evaluation. STUDY DESIGN: The animals were divided into three groups according to endodontic treatment performed: Group 1, single-visit endodontic treatment in teeth without apical periodontitis; Group 2, single-visit endodontic treatment in teeth with apical periodontitis; and Group 3, endodontic treatment in teeth with apical periodontitis using calcium hydroxide as a root canal dressing. Group 4 consisted of teeth with apical periodontitis not submitted to root canal treatment and Group 5 consisted of healthy teeth without periapical disease. Radiographic, tomographic, and microscopic evaluations were performed by blind examiners. At 180 days experimental time, CT and radiographic measurements of periapical disease were compared with the gold standard microscopic measurement using intraclass correlation coefficient. Intergroup comparisons considering different methods of periapical lesions measurement or different clinical protocols of root canal treatment were performed by Kruskal Wallis test followed by Dunn. Integrity of lamina dura, presence of radiolucent areas, and presence of root resorption were analyzed by Fisher's exact test. RESULTS: There was discontinuity of the lamina dura and CPD in all teeth from Groups 2, 3, and 4 evaluated by tomography and radiography 45 days after CPD induction. Radiographically, 180 days after root canal treatment, there was no periapical lesion in teeth from Groups 1 and 3, different from groups 2 and 4 (p < .05). The highest reduction in the CPD size was observed on Group 3 (p < .05). According to the tomographic results, there was decrease of the size of the CPD on Group 3 but not on Groups 2 or 4. However, in all groups the periapical lesions presented larger mesio-distal extension if compared with radiography, both 45 days after CPD induction and 180 days after root canal treatment. At 180 days, CT measurements were closely related to microscopic results (ICC = 0.95) differently from radiographic evaluation (ICC = 0.86). CONCLUSION: CT Scan evaluation of periapical repair following root canal treatment provided similar information than that obtained by microscopic analysis, whereas radiographic evaluation underestimated the size do periapical lesion.

Accuracy of periapical radiography and cone-beam computed tomography scans in diagnosing apical periodontitis using histopathological findings as a gold standard.

INTRODUCTION: The aim of this study was to evaluate the accuracy of two imaging methods in diagnosing apical periodontitis (AP) using histopathological findings as a gold standard. METHODS: The periapex of 83 treated or untreated roots of dogs' teeth was examined using periapical radiography (PR), cone-beam computed tomography (CBCT) scans, and histology. Sensitivity, specificity, predictive values, and accuracy of PR and CBCT diagnosis were calculated. RESULTS: PR detected AP in 71% of roots, a CBCT scan detected AP in 84%, and AP was histologically diagnosed in 93% (p = 0.001). Overall, sensitivity was 0.77 and 0.91 for PR and CBCT, respectively. Specificity was 1 for both. Negative predictive value was 0.25 and 0.46 for PR and CBCT, respectively. Positive predictive value was 1 for both. Diagnostic accuracy (true positives + true negatives) was 0.78 and 0.92 for PR and CBCT (p = 0.028), respectively. CONCLUSION: A CBCT scan was more sensitive in detecting AP compared with PR, which was more likely to miss AP when it was still present.