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

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

A comparison of estimated age based on pulp volume from cone beam computed tomography (CT) images and panoramic radiography data with chronological age.

This retrospective study was conducted to evaluate different methods for dental age estimation in children and to examine the feasibility of using cone beam computed tomography (CBCT) data for age estimation. A total of 200 radiographic records (both digital panoramic radiographs and CBCTs) were acquired from 100 children aged 9 to 16 years, all taken on the same dates. Radiographic data was acquired from archived records and included both panoramic radiography and CBCT data belonging to the same individual. CBCT was used when panoramic radiographic data was insufficient. The pulp volume and pulp/tooth volume ratio of the left first molar teeth in the mandible were calculated from the CBCT data using MIMICS software. In addition, age was estimated by the Demirjian and Willems methods from data obtained from panoramic radiography images. Statistical analyses and linear regression analysis were performed as necessary. There was a statistically significant difference between the mean difference between the Demirjian method and chronological age, and between the Willems method and chronological age (p < 0.001). Statistically significance was achieved in a linear regression model created from pulp volume (R2 = 0.098) and pulp/tooth volume ratio (R2 = 0.395) data for the estimated dental age analysis (p < 0.001) and a negative correlation was observed with chronological age. When compared estimated dental age from CBCT data with chronological age, the pulp/tooth volume ratio method yielded results closer to chronological age than using only pulp volume data. When considering both panoramic radiographic age estimation methods and age estimation methods using CBCT data, we found that the results obtained with the Willems method, a panoramic radiographic age estimation technique, provided the closest results to the chronological age. More contributions should be made to the literature regarding the feasibility of age estimation using pulp and tooth volume as an alternative method.

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

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

[Comparison of the impact of orthodontic treatment on pulp volume in adolescents and adults].

Objective: To compare the impact of orthodontic treatment on pulp volume in adolescents and adults. Methods: Cone-beam CT data of 62 patients undergoing orthodontic treatment at the Department of Orthodontics, Stomatological Hospital of Chongqing Medical University, from January 2019 to March 2022 were collected. Patients were divided into two age groups (31 patients in each group): adolescent group (aged 13-17, 17 males and 14 females) and adult group (aged 21-25, 12 males and 19 females). Pre-and post-treatment reconstructions of the pulp and dental tissues of upper first molars (UM1) and lower central incisors (L1) were performed. Measurements included pulp volume for UM1 (UM1 P) and L1 (L1 P), pulp chamber volume (UM1 PC) and root canal volume (UM1 RC) for UM1, root length for L1 (L1 RL), and mesiobuccal root length for UM1 (UM1 RL), as well as chamber heights at specific landmarks [the lengths from the central fossa fusion site to the roof of the pulp chamber (H1), the floor of the pulp chamber (H2), the nearest point of root divergence as well as crown-root bifurcation (H3), the farthest point of root divergence (H4), and the pulp chamber height (H5)] in UM1. Changes in these indices were calculated and analyzed using paired and independent sample t-tests for within-group and between-group differences, respectively. Pearson correlation was used to assess potential associations among H5, root length, and pulp volume changes. Results: Before and after orthodontic treatment, no significant difference was observed in the adult group for L1 P (t=-0.03, P=0.975), while significant differences were noted for UM1 P, UM1 PC, and UM1 RC (t=9.98, P<0.001; t=9.04, P<0.001; t=6.69, P<0.001). In the adolescent group, significant differences were found for both L1 P and UM1 P (t=2.25, P=0.029; t=6.30, P<0.001). After orthodontic treatment, the absolute value changes of UM1 P, UM1 PC, and L1 P in the adolescent group were (19.75±9.58), (15.07±7.65) and (1.89±6.29) mm3, respectively, and in the adult group were (13.33±9.41), (9.16±7.05) and (0.02±4.66) mm3, respectively (t=3.77, P<0.001; t=4.48, P<0.001; t=2.34, P=0.048). There was no significant absolute difference in the amount of UM1 RC between the two groups after orthodontic treatment (t=0.86, P=0.391). Before and after orthodontic treatment, the absolute value changes of L1 RL, H1 and H5 in the adolescent group were (0.54±0.41), (0.38±0.27) and (0.71±0.33) mm, respectively, and the absolute value changes in the adult group were (0.78±0.62), (0.26±0.20) and (0.57±0.28) mm, respectively (t=-2.43, P=0.017; t=2.96, P=0.004; t=2.57, P=0.011). Whereas no significant differences were observed for UM1 RL, H2, H3, and H4 (t=-0.85, P=0.400; t=0.43, P=0.669; t=-0.50, P=0.619; t=1.46, P=0.148). Additionally, significant correlations were found between changes in H5 and UM1 RL with UM1 P (r=0.35, P<0.001; r=0.19, P=0.030), but not between Changes in L1 RL and L1 P (r=0.11, P>0.05). Conclusions: The effect of orthodontic treatment on pulp volume in adolescents and adults were different.

Age estimation in adults by canine teeth: a systematic review of the Cameriere method with meta-analysis on the reliability of the pulp/tooth area ratio.

The age estimation of an adult using methods accessible to the forensic routine is a goal pursued by forensic experts. Cameriere, Ferrante and Cingolani (2004) proposed the use of the pulp/tooth area ratio of canine teeth as a promising variable, but its reliability has shown conflicting results in the scientific literature. This article aimed to carry out a systematic review with meta-analysis to verify whether the pulp/tooth area ratio of canine teeth includes a variable that can be used alone to estimate dental age in adults. A systematic search was carried out in six databases using keywords related to the theme in Portuguese, English, and Spanish. The study selection process followed pre-established eligibility criteria. Assessments were carried out regarding risk of bias and publication bias of selected studies, and meta-analysis was carried out considering Pearson's correlation coefficient between pulp/tooth area ratio and chronological age as effect measure. Most selected studies showed low risk of bias; no publication bias was found when all studies were considered, and potential publication bias was found when outliers were removed. Despite the high heterogeneity among studies and the need for more research, it could be observed that the pulp/tooth area ratio has strong negative correlation with chronological age, and the pulp/tooth area ratio could be derived from both periapical radiographs and orthopantomographs. Therefore, it is suggested that there is scientific evidence that the pulp/tooth area ratio obtained from canine teeth is reliable for dental age estimation in adults.

Early diagnosis of aortic calcification through dental X-ray examination for dental pulp stones.

Vascular calcification, an ectopic calcification exacerbated by aging and renal dysfunction, is closely associated with cardiovascular disease. However, early detection indicators are limited. This study focused on dental pulp stones, ectopic calcifications found in oral tissues that are easily identifiable on dental radiographs. Our investigation explored the frequency and timing of these calcifications in different locations and their relationship to aortic calcification. In cadavers, we examined the association between the frequency of dental pulp stones and aortic calcification, revealing a significant association. Notably, dental pulp stones appeared prior to aortic calcification. Using a rat model of hyperphosphatemia, we confirmed that dental pulp stones formed earlier than calcification in the aortic arch. Interestingly, there were very few instances of aortic calcification without dental pulp stones. Additionally, we conducted cell culture experiments with vascular smooth muscle cells (SMCs) and dental pulp cells (DPCs) to explore the regulatory mechanism underlying high phosphate-mediated calcification. We found that DPCs produced calcification deposits more rapidly and exhibited a stronger augmentation of osteoblast differentiation markers compared with SMCs. In conclusion, the observation of dental pulp stones through X-ray examination during dental checkups could be a valuable method for early diagnosis of aortic calcification risk.

Detection of the pathological exposure of pulp using an artificial intelligence tool: a multicentric study over periapical radiographs.

BACKGROUND: Introducing artificial intelligence (AI) into the medical field proved beneficial in automating tasks and streamlining the practitioners' lives. Hence, this study was conducted to design and evaluate an AI tool called Make Sure Caries Detector and Classifier (MSc) for detecting pathological exposure of pulp on digital periapical radiographs and to compare its performance with dentists. METHODS: This study was a diagnostic, multi-centric study, with 3461 digital periapical radiographs from three countries and seven centers. MSc was built using Yolov5-x model, and it was used for exposed and unexposed pulp detection. The dataset was split into a train, validate, and test dataset; the ratio was 8-1-1 to prevent overfitting. 345 images with 752 labels were randomly allocated to test MSc. The performance metrics used to test MSc performance included mean average precision (mAP), precision, F1 score, recall, and area under receiver operating characteristic curve (AUC). The metrics used to compare the performance with that of 10 certified dentists were: right diagnosis exposed (RDE), right diagnosis not exposed (RDNE), false diagnosis exposed (FDE), false diagnosis not exposed (FDNE), missed diagnosis (MD), and over diagnosis (OD). RESULTS: MSc achieved a performance of more than 90% in all metrics examined: an average precision of 0.928, recall of 0.918, F1-score of 0.922, and AUC of 0.956 (P<.05). The results showed a higher mean of 1.94 for all right (correct) diagnosis parameters in MSc group, while a higher mean of 0.64 for all wrong diagnosis parameters in the dentists group (P<.05). CONCLUSIONS: The designed MSc tool proved itself reliable in the detection and differentiating between exposed and unexposed pulp in the internally validated model. It also showed a better performance for the detection of exposed and unexposed pulp when compared to the 10 dentists' consensus.

Age estimation based on 3D pulp segmentation of first molars from CBCT images using U-Net.

OBJECTIVE: To train a U-Net model to segment the intact pulp cavity of first molars and establish a reliable mathematical model for age estimation. METHODS: We trained a U-Net model by 20 sets of cone-beam CT images and this model was able to segment the intact pulp cavity of first molars. Utilizing this model, 239 maxillary first molars and 234 mandibular first molars from 142 males and 135 females aged 15-69 years old were segmented and the intact pulp cavity volumes were calculated, followed by logarithmic regression analysis to establish the mathematical model with age as the dependent variable and pulp cavity volume as the independent variable. Another 256 first molars were collected to estimate ages with the established model. Mean absolute error and root mean square error between the actual and the estimated ages were used to assess the precision and accuracy of the model. RESULTS: The dice similarity coefficient of the U-Net model was 95.6%. The established age estimation model was [Formula: see text] (V is the intact pulp cavity volume of the first molars). The coefficient of determination (R2), mean absolute error and root mean square error were 0.662, 6.72 years, and 8.26 years, respectively. CONCLUSION: The trained U-Net model can accurately segment pulp cavity of the first molars from three-dimensional cone-beam CT images. The segmented pulp cavity volumes could be used to estimate the human ages with reasonable precision and accuracy.

Volumetry of ovine incisors dental pulp for further regenerative therapy.

Mesenchymal stem cells (MSCs) are used for regenerative therapy. Dental pulp MSCs make extracted wisdom teeth a useful resource in humans. Preclinical validation of regenerative therapies requires large animal models such as the sheep. Since stem cells can be retrieved from the dental pulp of ovine incisors, the best age to extract a maximal volume of dental pulp needs to be defined. The objective of this ex vivo study was to quantify incisors dental pulp volume, in sheep of various age. Three jaws were dedicated to histology (one per age group); the others were imaged with a computed tomography scanner [3 years-old (n = 9), 4 (n = 3) and 6 (n = 5)]. The incisors dental pulp volume was measured after 3D reconstruction. Multiple linear regression showed that dental pulp volume of ovine incisors decreases with age (ß-estimate = -3.3; p < 0.0001) and teeth position from the more central to the more lateral (ß-estimate = -4.9; p = 0.0009). Weight was not a relevant variable in the regression model. The dental pulp volume ranged from 36.7 to 19.6 mm3 in 3-year-old sheep, from 23.6 to 11.3 in 4-year-old sheep, and from 19.4 to 11.5 in 6-year-old sheep. The pulp volume of the most central teeth (first intermediate) was significantly higher than the most lateral teeth (corner). Haematoxylin-Eosin-Safran of the whole incisors, and of isolated dental pulps demonstrated a similar morphology to that in humans. The first intermediate incisor of 3-year-old sheep should be selected preferentially in preclinical research to retrieve the highest volume of dental pulp.

Multimodal Imaging of Dental Pulp Healing Patterns Following Tooth Autotransplantation and Regenerative Endodontic Treatment.

INTRODUCTION: Understanding the healing process of dental pulp after tooth autotransplantation (TAT) and regenerative endodontic treatment (RET) of immature teeth is important both clinically and scientifically. This study aimed to characterize the pattern of dental pulp healing in human teeth that underwent TAT and RET using state-of-the-art imaging techniques. MATERIALS AND METHODS: This study examined 4 human teeth, 2 premolars that underwent TAT, and 2 central incisors that received RET. The premolars were extracted after 1 year (case 1) and 2 years (case 2) due to ankylosis, while the central incisors were extracted after 3 years (cases 3 and 4) for orthodontic reasons. Nanofocus x-ray computed tomography was used to image the samples before being processed for histological and immunohistochemical analysis. Laser scanning confocal second harmonic generation imaging (SHG) was used to examine the patterns of collagen deposition. A maturity-matched premolar was included as a negative control for the histological and SHG analysis. RESULTS: Analysis of the 4 cases revealed different patterns of dental pulp healing. Similarities were observed in the progressive obliteration of the root canal space. However, a striking loss of typical pulpal architecture was observed in the TAT cases, while a pulp-like tissue was observed in one of the RET cases. Odontoblast-like cells were observed in cases 1 and 3. CONCLUSIONS: This study provided insights into the patterns of dental pulp healing after TAT and RET. The SHG imaging sheds light on the patterns of collagen deposition during reparative dentin formation.

Evaluation of the expression of nerve fiber markers in healthy and inflamed dental pulp.

The diagnosis of irreversible pulpitis (IP) depends on clinical data, especially the chief complaint of the patient, visual inspection, response to the application of stimuli, and radiographic examination. The characterization of nerve fibers (NF) in IP may contribute to better interpret painful symptoms, but has been barely explored. This study sought to characterize the density and integrity of NF in 16 samples of IP and in five healthy pulps (HP) using S-100 and PGP 9.5 markers. Immunohistochemistry was performed to determine the density/mm2 of S-100+ and PGP 9.5+ in NF. The amount of degenerated NF was obtained by subtracting the total NF density from the amount of intact NF. Associations between NF density and integrity and symptomatology were calculated. All samples were positive for S-100 and PGP 9.5. Compared to HP samples (38.20/mm2), IP samples had a lower density of intact NF (6.24/mm2). A significantly higher density of degenerated NF was found in IP samples with spontaneous pain (39.59/mm2) compared to those with provoked pain (23.96/mm2) (p = 0.02). No association was observed between intensity of the inflammatory infiltrate and NF density and integrity (p > 0.05). The findings of this study suggest that pulpitis may involve different stages of degeneration and may be more advanced in cases with spontaneous pain. The symptoms reported by affected individuals do not appear to depend on the intensity of the inflammatory infiltrate, but rather on the integrity of NF.

The effect of pulp volume and impact direction on the stress and strain distribution during an impact.

BACKGROUND/AIM: Dentoalveolar trauma has a high incidence in different age groups, including the extremes, children, and older people. Mouth aging leads to some changes, one of them being the pulp volume reduction. The aim of this study was to evaluate the influence of different pulp cavity volumes and the impact direction on the stress and strain distribution of a maxillary central incisor. MATERIAL AND METHODS: Twenty cone beam computed tomography sets of images were selected and the pulp cavity volume was measured by ITK-SNAP software. The mean pulp cavity volume for age group of 10- to 12-year-olds was calculated to obtain the largest one. Subsequent reductions (25%, 50%, 75% and 100%) in the pulp volume values were made to simulate the aging process. The maxilla anterior segment was modeled in the Rhinoceros 5.0 software. The three-dimensional volumetric mesh was generated using the Patran software (MSC. Software), with isoparametrics, 4-noded tetrahedral elements, and exported to Marc/Mentat (MSC. Software) as element number 134. A non-linear dynamic impact analysis was performed in which a steel ball reached the central incisor at a speed of 5 m/s in the horizontal or vertical direction. The stresses were evaluated by modified von Mises stresses. The strains and the total displacement were also recorded. RESULTS: The pulp volume mean value for the age group of 10- to 12-year-olds was 65.05 mm3 . Stress concentrations were slightly different for the different pulp volumes. Impact directions resulted in different stress distribution. Higher stress values were present with the horizontal impact (range between 25.18 MPa and 24.08 MPa for enamel and 38.89 MPa and 37.03 for dentin) when compared to vertical impact (range between 15.30 MPa and 14.58 for enamel and 24.77 to 22.03 MPa for dentin). Total displacement was different for the two impact directions and higher for the horizontal impact. CONCLUSION: Pulp volume did not significantly affect the stress, strain, and total displacement during the impact but the impact direction did affect the evaluated parameters during impact.

Assessment of the Maximum Amount of Orthodontic Force for Dental Pulp and Apical Neuro-Vascular Bundle in Intact and Reduced Periodontium on Bicuspids (Part II).

This study examines 0.6 N-4.8 N as the maximum orthodontic force to be applied to dental pulp and apical NVB on intact and 1-8 mm reduced periodontal-ligament (PDL), in connection with movement and ischemic, necrotic and resorptive risk. In addition, it examines whether the Tresca finite-element-analysis (FEA) criterion is more adequate for the examination of dental pulp and its apical NVB. Eighty-one (nine patients, with nine models for each patient) anatomically correct models of the periodontium, with the second lower-premolar reconstructed with its apical NVB and dental pulp were assembled, based on X-ray CBCT (cone-beam-computed-tomography) examinations and subjected to 0.6 N, 1.2 N, 2.4 N and 4.8 N of intrusion, extrusion, translation, rotation, and tipping. The Tresca failure criterion was applied, and the shear stress was assessed. Forces of 0.6 N, 1.2 N, and 2.4 N had negligible effects on apical NVB and dental pulp up to 8 mm of periodontal breakdown. A force of 4.8 N was safely applied to apical NVB on the intact periodontium only. Rotation and tipping seemed to be the most invasive movements for the apical NVB. For the dental pulp, only the translation and rotation movements seemed to display a particular risk of ischemia, necrosis, and internal orthodontic-resorption for both coronal (0-8 mm of loss) and radicular pulp (4-8 mm of loss), despite the amount of stress being lower than the MHP. The Tresca failure criterion seems more suitable than other criteria for apical NVB and dental pulp.

Assessment of the Best FEA Failure Criteria (Part II): Investigation of the Biomechanical Behavior of Dental Pulp and Apical-Neuro-Vascular Bundle in Intact and Reduced Periodontium.

The aim of this study was to biomechanically assess the behavior of apical neuro-vascular bundles (NVB) and dental pulp employing Tresca, Von Mises, Pressure, S1 and S3 failure criterions in a gradual periodontal breakdown under orthodontic movements. Additionally, it was to assess the accuracy of failure criteria, correlation with the maximum hydrostatic pressure (MHP), and the amount of force safe for reduced periodontium. Based on cone-beam computed tomography, 81 3D models of the second lower premolar were subjected to 0.5 N of intrusion, extrusion, rotation, tipping, and translation. A Finite Elements Analysis (FEA) was performed. In intact and reduced periodontium apical NVB, stress (predominant in all criteria) was significantly higher than dental pulp stress, but lower than MHP. VM and Tresca displayed identical results, with added pulpal stress in translation and rotation. S1, S3 and Pressure showed stress in the apical NVB area. 0.5 N seems safe up to 8 mm periodontal breakdown. A clear difference between failure criteria for dental pulp and apical NVB cannot be proved based only on the correlation quantitative results-MHP. Tresca and VM (adequate for ductile materials) showed equivalent results with the lowest amounts of stress. The employed failure criteria must be selected based on the type of material to be analyzed.

Pulp blood flow changes in maxillary and mandibular anterior teeth after orthodontic retraction: a prospective study.

BACKGROUND: Previous studies of pulpal blood flow (PBF) changes in anterior teeth have been limited in the early phase of orthodontic treatment; less is known about the blood supply of anterior teeth in bimaxillary protrusion patients after orthodontic retraction. METHODS: Fifty bimaxillary protrusion patients (25 orthodontic patients ready for debonding and 25 non-orthodontic patients) were selected as study participants. The PBF of maxillary and mandibular anterior teeth were measured using laser Doppler flowmetry. For orthodontic patients, the PBF was measured at 1 day (T1), 1 month (T2), and 3 months (T3) after fixed appliance removal. Non-orthodontic patient PBF was measured as a control. Cone-beam computed tomography (CBCT) examinations before and after orthodontic treatment were performed for orthodontic patients to measure the root resorption. The anterior teeth in orthodontic group were further divided into subgroups according to root resorption and patient age. RESULTS: At T1 and T3, PBF changes did not differ significantly between the orthodontic and non-orthodontic groups. Maxillary lateral incisor, maxillary central incisor, and mandibular lateral incisor PBFs at T2 were significantly higher in the orthodontic group (P = 0.048, P = 0.04, and P = 0.021). No significant difference in PBF was found between the root resorption and non-resorption subgroups at any time point. Adolescent patients showed a higher PBF in the maxillary lateral incisor at T2 (12.23 ± 3.48) relative to that at T1 (9.10 ± 3.76) and T3 (9.81 ± 2.80) with statistically significant difference (P = 0.020). CONCLUSION: For bimaxillary protrusion patients with four premolars extraction, PBF in the maxillary anterior teeth increased transiently after orthodontic appliance removal and then returned to non-orthodontic levels 3 months later. This effect was more pronounced in adolescents. The PBF of anterior teeth after orthodontic retraction may not be influenced by root resorption.

Techniques for Preserving Pulp Vitality in an Asymptomatic Deep Carious Lesion: A Clinical Case Study.

When complete caries removal will lead to pulp exposure, partial caries removal may be considered as an alternative treatment option. Various techniques can be used in such situations to preserve pulp vitality. Incomplete removal of carious dentin and subsequent carious dentin sealing has been found to result in the arrest of carious lesions in deciduous and permanent teeth. This case report documents the treatment a young patient who presented with a mandibular left first molar that exhibited active coronal caries that had reached the apical third of the dentin. With a high risk of pulp exposure, the case demonstrates the use of conservative procedures that produced effective results in preserving pulp vitality.

Comparative evaluation of dental pulp tests in pulpal status diagnostics / Evaluación comparativa de pruebas de pulpa dental en el diagnóstico del estado pulpar

Introduction: The purpose of this study was to evaluate the effectiveness and compare the accuracy of pulp tests in the diagnosis of teeth pulpal health. Material and Methods: Traumatized (n=71) and non-traumatized (n=71) teeth from 42 patients were evaluated. Each tooth underwent cold, heat, electric and oximetry tests, followed by radiographic examination and calculation of the sensitivity, specificity, PPV, NPV and accuracy. Results: Clinical and radiographic examination showed no alteration for the 71 teeth from the intact contralateral group. From the traumatized group, 29 teeth presented complete endodontic treatment, 17 presented periapical alterations that required endodontic treatment and 25 teeth did not present conclusive radiographic alteration. The cold test showed a significantly higher proportion of correct results, while the electric test showed a significantly lower proportion. The data showed higher accuracy for the cold, followed by oximeter and heat tests, while the electric test presented the lowest accuracy. Cold and oximeter tests proved superior over the electric and heat tests, while the electric test showed better parameters when diagnosing diseased pulp. Conclusion: Combining two pulp tests seems reasonable for improving the pulp diagnoses using both oximeter and cold or oximeter and heat tests to detect healthy pulp; or cold and electric tests to define diseased pulp.

Introducción: El propósito de este estudio fue evaluar la efectividad y comparar la precisión de las pruebas pulpares en el diagnóstico de la salud pulpar de los dientes. Material y Métodos: Se evaluaron dientes traumatizados (n=71) y no traumatizados (n=71) de 42 pacientes. Cada diente se sometió a pruebas de frío, calor, eléctricas y de oximetría, seguidas de examen radiográfico y cálculo de la sensibilidad, especificidad, VPP, VPN y precisión. Resultados: El examen clínico y radiográfico no mostró alteración en los 71 dientes del grupo contralateral intacto. Del grupo traumatizado, 29 dientes presentaron tratamiento endodóntico completo, 17 presentaron alteraciones peri-apicales que requirieron tratamiento endodóntico y 25 dientes no presentaron alteración radiográfica concluyente. La prueba en frío mostró una proporción significativamente mayor de resultados correctos, mientras que la prueba eléctrica mostró una proporción significativamente menor. Los datos mostraron mayor precisión para la prueba de frío, seguida de las pruebas de oxímetro y calor, mientras que la prueba eléctrica presentó la menor precisión. Las pruebas de frío y oxímetro demostraron ser superiores a las pruebas eléctricas y de calor, mientras que la prueba eléctrica mostró mejores parámetros al momento de diagnosticar pulpa enferma. Conclusión: La combinación de dos pruebas pulpares parece razonable para mejorar los diagnósticos pulpares utilizando tanto el oxímetro como las pruebas de frío u oxímetro y calor para detectar una pulpa sana; o pruebas de frío y eléctricas para definir pulpa enferma.

Spatiotemporal dynamics of brain function during the natural course in a dental pulp injury model.

PURPOSE: Toothache, a common disorder afflicting most people, shows distinct features at different clinical stages. This study aimed to depict metabolic changes in brain and investigate the potential mechanism involved in the aberrant affective behaviors during the natural process of toothache. METHODS: We investigated the spatiotemporal patterns of brain function during the natural course of toothache in a rat model of dental pulp injury (DPI) by using positron emission tomography (PET). RESULTS: Glucose metabolism peaked on the 3rd day and gradually decreased in several brain regions after DPI, which was in line with the behavioral and histological results. PET imaging showed that visual pathway was involved in the regulation of toothache. Meanwhile, the process of emotional regulation underlying toothache was mediated by N-methyl-D-aspartic receptor subunit 2B (NR2B) in the caudal anterior cingulate cortex (cACC). CONCLUSION: Our results revealed the spatiotemporal neurofunctional patterns during toothache process and preliminarily elucidated the role of NR2B in cACC in the regulation of toothache-related affective behaviors.

Evaluation of electric pulp test thresholds and correct probe tip placement site in developing incisors: a clinical study in 1200 teeth.

PURPOSE: Although electric pulp tests (EPT) may play a valuable diagnostic role in traumatized immature permanent teeth, the EPT threshold values which can be used as reference are not known. The aim of this study was to determine the average range of EPT threshold values in healthy permanent incisors according to their stage of root development. METHODS: A total of 1200 permanent incisors were examined in 273 children (142 girls, 131 boys) aged 6-12 years. Panoramic radiographs were used to group teeth according to the stage of root development. A digitest II pulp vitality tester (Parkell, Inc, Edgewood, NY) was used along with toothpaste as the conducting medium to determine sensibility on three different sites (incisal, middle and cervical third). RESULTS: In all teeth, mean EPT values showed a tendency to decrease along with advanced root development. Irrespective of the stage of root development, the lowest EPT values were obtained when measurements were made on the incisal third of the crown (p < 0.001). Mandibular incisors had lower mean response thresholds than their maxillary counterparts. CONCLUSION: The present findings provide reference EPT threshold values according to stage of tooth development to monitor the post traumatic pulp status of permanent incisors.

Automatic exposure compensation in intraoral digital radiography: effect on the gray values of dental tissues.

BACKGROUND: This study aimed to investigate the effect of automatic exposure compensation (AEC) of intraoral radiographic systems on the gray values of dental tissues in images acquired with or without high-density material in the exposed region using different exposure times and kilovoltages. The influence of the distance of the high-density material was also investigated. METHODS: Radiographs from the molar region of two mandibles were obtained using the RVG 6100 and the Express systems, operating at 60 and 70 kV and 0.06, 0.10, and 0.16 s. Subsequently, a titanium implant was inserted in the premolar's socket and other images were acquired. Using the ImageJ software, two regions of interest were determined on the enamel, coronary dentine, root dentine, and pulp of the first and second molars to obtain their gray values. RESULTS: In the RVG 6100, the implant did not affect the gray values (p > 0.05); the increase in kV decreased it in all tissues (p < 0.05), and the exposure time affected only the root dentine and pulp. In the Express, only enamel and coronary dentine values changed (p < 0.05), decreasing with the implant presence and/or with the increase in exposure factors. The distance of the implant did not affect the results (p > 0.05). CONCLUSIONS: AEC's performance varies between the radiographic systems. Its effect on the gray values depends not only on the presence or absence of high-density material but also on the kV and exposure time used.