Apical Foramen Research Articles

Morphological changes of the apical foramen after enlargement: A scoping review of in vitro studies.

To outline the current evidence on root morphological changes after enlarging the apical foramen with NiTi instruments. A search was performed in the Virtual Health Library, PubMed, EMBASE, Scopus, Web of Science, Science Direct and SciELO databases, in addition to a manual search in Google Scholar, between January 2017 and October 2023. Articles published in English that describe in vitro studies investigating root morphological changes after instrumentation 1 mm beyond the major apical foramen were included. The quality of evidence in the included studies was also analyzed. The search retrieved 367 articles. Of these, four studies were eligible for data synthesis and analysis, all of them in vitro studies. Synthesis of the results of these in vitro studies showed a larger number of root morphological changes such as experimental dentinal microcraks in samples submitted to instrumentation beyond the apical foramen when compared to micro-CT images obtained before preparation. The in vitro studies analyzed in this scoping review indicate that instrumentation beyond the major foramen of the root canal, promotes morphological changes in this area and that the adoption of standardized methodologies would not only increase the accurate detection and characterization of these changes but also facilitate the application of these findings in clinical trials and patient care. Key words:Endodontics, apical morphology, root canal preparation.

Reliability of Three-Dimensional Micro-Computed Tomography Root Canal Analysis Using Drishti Software: A Pilot Study

In recent years, micro-computed tomography (micro-CT) has become a promising tool for non-destructive imaging and the study of root canal morphology in endodontics. However, the reliability of such analyses heavily relies on the accuracy and consistency of the software used for image processing. Objective: This study aims to investigate the reliability of two different micro-CT voxel sizes using open-source three-dimensional (3D) software (Drishti v3.0) used to identify and quantify the Apical Foramen (AF) and Apical Constriction (AC) in mandibular premolars. Methods: Eight mandibular premolars were divided into two groups, with four samples in each group. Samples were scanned using a ZEISS X-Radia 520 Micro-CT system with two different voxel sizes of 23 µm (Group A) and 17 µm (Group B), respectively. The micro-CT data were reconstructed and transferred to Drishti Software, and individual image rendering was performed to visualize the images for data analysis. The position and measurement of AF and AC to the anatomical apex were measured individually and independently by single operators. Results: The reliability of the measurements assessed using Intraclass Correlation Coefficients (ICCs) between two voxel sizes was excellent and on par with previous research. This pilot study suggested that results for voxel sizes of 23 µm and 17 µm were comparable. Both voxel size 3D images demonstrated excellent and high-quality visualization of the root canal configuration, lateral and accessory canals, apical deltas, major AF, and AC. Conclusion: It is feasible and reliable to visualize and analyze 3D micro-CT images using open-source software (Drishti v3.0). Both voxel sizes of 23 µm and 17 µm are recommended for use in root canal study.

Influence of root shape on canal complexity at the mandibular molar apical surgical resection level: A micro-CT study

ObjectivesThis study aimed to investigate the relationship between the aspect ratios of mandibular molar roots at the apical 3-mm level and their root canal complexity. DesignThis study used micro-CT imaging to analyze 163 two-rooted mandibular molars. The aspect ratios of the roots at the apical 3-mm level were categorized as "< 2.75" or "≥ 2.75" (mesial) and "< 1.75" or "≥ 1.75" (distal). A two-dimensional (2D) analysis focused on four apical axial cross-section levels to determine the presence of main and accessory canals and isthmus. Additionally, a three-dimensional (3D) assessment of the apical 4-mm of both roots examined main and accessory canals, apical foramina, apical deltas, and middle mesial canals. ResultsMesial roots with aspect ratios ≥ 2.75 showed a higher number of main canals at all levels compared to those with aspect ratios < 2.75 at the 3-mm level. Additionally, the ≥ 2.75 group exhibited more accessory canals and a higher average number of accessory canals. The 3D assessment confirmed significantly more accessory canals and apical foramina in the ≥ 2.75 group. The prevalence of roots with apical deltas was nearly double in the ≥ 2.75 group, and middle mesial canals were exclusively found in this group. In the distal root, the ≥ 1.75 group showed a significantly higher number of main canals at all axial levels. No significant differences were observed between groups in terms of accessory canals, apical foramina, or deltas. ConclusionsA higher root aspect ratio is related to higher anatomical complexity.

Artificial Intelligence in Adult and Pediatric Dentistry: A Narrative Review.

Artificial intelligence (AI) has been recently introduced into clinical dentistry, and it has assisted professionals in analyzing medical data with unprecedented speed and an accuracy level comparable to humans. With the help of AI, meaningful information can be extracted from dental databases, especially dental radiographs, to devise machine learning (a subset of AI) models. This study focuses on models that can diagnose and assist with clinical conditions such as oral cancers, early childhood caries, deciduous teeth numbering, periodontal bone loss, cysts, peri-implantitis, osteoporosis, locating minor apical foramen, orthodontic landmark identification, temporomandibular joint disorders, and more. The aim of the authors was to outline by means of a review the state-of-the-art applications of AI technologies in several dental subfields and to discuss the efficacy of machine learning algorithms, especially convolutional neural networks (CNNs), among different types of patients, such as pediatric cases, that were neglected by previous reviews. They performed an electronic search in PubMed, Google Scholar, Scopus, and Medline to locate relevant articles. They concluded that even though clinicians encounter challenges in implementing AI technologies, such as data management, limited processing capabilities, and biased outcomes, they have observed positive results, such as decreased diagnosis costs and time, as well as early cancer detection. Thus, further research and development should be considered to address the existing complications.

Histologic Assessment of a Fast-Set Mineral Trioxide Aggregate (MTA) and Two Novel Antibacterial-Enhanced Fast-Set MTAs for Apexification and Periapical Healing of Teeth With Incomplete Root Formation in a Rat Model: An In Vivo Animal Study.

Background Pulp necrosis in incomplete root formation halts dentine development, resulting in larger canals with fragile walls and an open apex, complicating canal instrumentation and apical stop formation. Bioactive endodontic cements such as mineral trioxide aggregate (MTA) are crucial for creating artificial apical barriers or inducing apical foramen closure, but challenges remain regarding their antimicrobial efficacy and cytotoxicity. Modifications to MTA formulations aim to address these concerns. Methods This in vivo animal study involved 80 Wistar albino rats, with incomplete root formation induced by pulp exposure. Rats were divided into four groups receiving different MTA formulations for apexification: conventional MTA, modified MTA, and MTA enhanced with metronidazole or doxycycline. Histopathological evaluations were conducted at seven and 28 days post-treatment to assess calcific barrier formation, inflammatory reactions, and antimicrobial efficacy. Results By day 7, modified MTA formulations exhibited enhanced antibacterial activity compared to conventional MTA(p = 0.000), with fewer inflammatory reactions and microorganisms. By day 28, modified formulations showed superior calcific barrier formation, particularly in the metronidazole-and doxycycline-enhanced groups compared to conventional MTA (p = 0.000). These outcomes suggest that modifications to MTA formulations improve antimicrobial efficacy and calcific barrier formation in vivo. Conclusion Novel modified MTA formulations, particularly those enhanced with metronidazole or doxycycline, exhibit superior antibacterial efficacy and calcific barrier formation compared to conventional MTA. Further long-term studies are warranted to validate these findings for potential clinical translation.

Evaluation of Yazd General Dentists’ Knowledge about Vital Pulp Therapy in Immature Permanent Teeth in 2022

Introduction: Vital pulp therapy includes is differnt methods that are used to preserve pulp vitality and root development in immature permanent teeth with thin dentin wall and open apical foramen which have been damaged or inflamed due to dental caries, trauma, or during the restoration. This study was conducted to assess the knowledge of Yazd general dentists toward Vital pulp therapy in immature permanent teeth in 2022. Methods: In this descriptive-cross-sectional study, a valid and reliable questionnaire, including demographic information and 15 questions related to the knowledge of vital pulp therapy was distributed among 150 general dentists in Yazd City, Iran. Data were analyzed using SPSS-22 software, T-test and ANOVA. Results: The participants in this study, included 55.3% men and 44.7% women with an average age of 34.25 (±7.32) years old and an average years of job experience of 8.32 (±7.04). Among them, 35.3% had participated in dentistry retraining courses. The average knowledge score of the participants in this study was 9.2 out of 15. The average score in different groups did not show any significant difference in terms of age, sex, job experience, work place and participation in retraining courses. (P-value &gt;0.05) Conclusion: Yazd general dentists had intermediate level of knowledge about the vital pulp therapy of immature permanent teeth. It seems that the need for retraining courses to improve the level of knowledge about vital pulp therapy to help choosing the best treatment plan for young permanent teeth is evident.

Human costal cartilage, tooth cavities, and femur nutrient canals—new niches for insects used in forensic entomology

Abstract The study aimed to analyze the entomological material collected during 13 autopsies performed on the unidentified cadavers revealed at different stages of decay in the Upper Silesia Region (Poland) over 2016–2022. During the preparation of human tissues for genetic identification, we revealed larvae, puparia, and adult insects in previously undescribed locations: costal cartilage, femur nutrient canals (foramen nutrients), and tooth cavities. The taxonomical assessment was done using morphological examination or DNA barcoding, where necessary. Based on our observations, we conclude that the apical constriction, foramen, and cavities may serve as migration paths inside teeth, and the femur nutrient canals to the bone marrow. The study also revealed that Necrobia ruficollis (Fabricius, 1775) and Pyralidae Latreille, 1802 (Phycitinae) moths can form pupal chambers inside the costal cartilage, indicating that these insects can complete their life cycle inside this cache. We believe that the newly reported locations of carrion insects in human remains may be relevant to forensic entomology, as they provide new opportunities to collect insect evidence.

Assessment of the quality of root canal obturation of teeth with destructive forms of periodontitis using Silpex (SEM studies)

AIM. To evaluate the effectiveness of using the material Sealpex with gutta-percha pins using the lateral condensation method for permanent obturation of the root canals of teeth with periapical pathology and pathologically destroyed apical constriction.MATERIAL AND METHODS. The root canals of 94 teeth with destructive forms of periodontitis were filled with Sealpex. Depending on the degree of apical constriction, patients were divided into three groups. Follow-up of patients was carried out for 4 years.RESULTS. Using SEM, in 80% of cases, single micro cracks were detected between the dentin of the root canal wall and the sealer. In the area of wide apical openings, the fit of the material is loose, and it is removed beyond the root apex. The material diffuses into the root dentin. Statistical studies have shown a high percentage of successful treatment of destructive forms of periodontitis with the use of Sealpex.CONCLUSIONS. Endo-sealant extended beyond the apex of the root canal does not mean dense obturation of the apical foramen. The presence of micropores and microcracks in the endosealant can be regarded as evidence of poor sealing of the channel. The use of Sealpex is especially effective when filling teeth of groups, I and II with destructive forms of periodontitis

Clinical study of iRoot-BP combined with collagen sponge in treatment of periapical inflammation

The purpose of this research was to observe the clinical effect of iRoot-BP combined with collagen sponge for the treatment of periapical inflammation with lesions larger than 10 mm and undeveloped apical foramen. 26 teeth from 25 patients with periapical inflammation meeting the inclusion criteria were randomly assigned into two groups with 13 teeth per group. In collagen sponge group, the apical barrier was performed using iRoot-BP combined with collagen sponge, and in non-collagen sponge group was only treated with iRoot-BP. Patients in two groups were followed up at 3, 6 and 12 months respectively, and the therapeutic effect was judged according to the clinical and imaging findings. The prognosis of periapical lesions indicated that there were 13 of treated teeth in collagen sponge group and 11 of treated teeth in non-collagen sponge group show no signs of clinical or radiographic failure (χ2 = 2.167, p = 0.14). The observation results of continued root growth suggested that the average root growth of collagen group was 2 mm, while no continuous root growth was observed in non-collagen sponge group (p &lt; 0.05). Application of iRoot-BP combined with collagen sponge has obvious advantages in treatment of large-scale periapical inflammation with undeveloped apical foramen, which can promote the formation of immature roots closer to the normal roots.

A retrospective cohort study of pulp prognosis in luxated permanent teeth: a competing risk analysis.

The present retrospective cohort study aimed to evaluate luxated permanent teeth for pulp prognosis and risk factors. Case records and radiographs of 224 patients, involving 427 luxated permanent teeth, referred for treatment at the Dental Trauma Center-School of Dentistry, Universidade Federal de Minas Gerais, (DTC-SD-UFMG) from 2014 to 2022, were assessed for pulp prognosis classified as vitality, necrosis and pulp canal obliteration (PCO). A competing risk survival analysis estimated the hazards of the three outcomes, and the effect of demographic, clinical and treatment variables was tested using a cause specific Cox regression model. Pulp vitality was found in163 teeth (38.2%), pulp necrosis in 120 teeth (28.1%) and 55 teeth (12.9%) developed PCO. Pulp vitality decreased in the presence of concomitant crown fractures (HR 0.38 95% CI [0.2-0.8] p = 0.006). The risk of pulp necrosis (HR 0.62 95% CI [0.4-0.96] p = 0.03) was lower in cases with open apices but increased with concomitant crown fractures (HR 4.0 95% CI [2.6-6.1] p = 0.001) and intrusions (HR 2.3 95% CI [1.2-4.1] p = 0.007). Lateral or extrusive luxations (HR 3.0 95% CI [1.3-6.9] p = 0.001) and open apices (HR 2.4 95% CI [1.2-4.7] p = 0.01) showed higher rates of PCO. Type of luxation, the diameter of the apical foramen, and the presence of concomitant crown fractures were main determinants of pulp prognosis after luxation injuries in permanent teeth. Pulp prognosis after tooth luxation is dependent on the presence and direction of tooth displacement together with infection control. Not applicable.

Comparative evaluation of accuracy of working length determination with fifth-generation apex locator using two different techniques: An in vitro study.

Accurate working length (WL) determination is essential for successful root canal therapy. The aim of this study was to compare the difference between two different techniques in locating minor constriction using fifth-generation electronic apex locator. A detailed protocol explaining the procedures of the study was submitted to the institutional ethics committee. Forty extracted human permanent canine teeth were selected. WL was measured three times for each sample by three different examiners for both the conventional and experimental techniques at different time intervals. Interexaminers were blinded to their measurements, and the person who analyzed mean value was also blinded with techniques. Finally, radiographic working length was obtained using 15 size K-file. A size 20 K-file was cemented into the measured position with glass ionomer cement. Each tooth was viewed under a stereomicroscope at ×40 magnification. The distance from the file tip to the root apex was measured and calibrated to the nearest tenth of a millimeter. Using Stata statistical software (Version 17, Statacorp, College Station, Texas, USA). The agreement between raters and techniques was determined using intraclass correlation coefficient "ICC" and Bland-Altman plot. The "experimental method" (0.95, 95%) showed better agreement between the raters in comparison with the "conventional method" (0.93, 95%). The experimental technique showed perfect agreement between examiners in locating the minor constriction of the apical foramen.

How Does Intentional Apical Foraminal Enlargement Affect the Foramen and Root Canal Morphology?

IntroductionThis study assessed the effect of intentional foraminal enlargement on the foramen and the apical root canal morphology. MethodSixty mesial roots of mandibular molars were scanned by micro-computed tomography. Their apical foramina were photographed with a stereomicroscope before and after preparation. Three groups were formed (n = 20) according to the working length (WL). G-1: foramen - 1 mm; G0: foramen; and G+1: foramen + 1 mm. Each group originated 2 subgroups (n = 10): G-1: Buchanan's patency (size 10 K-type file) and foraminal debridement (sizes 20, 25 and 30 K-type files); G0 and G+1: rotary foraminal enlargement (ProDesign S size 25/.08) or reciprocating foraminal enlargement (R25). The area, perimeter, transportation, and noninstrumented walls of the foramen were evaluated. The root canal transportation and the centering index of preparation at 1, 3 and 5 mm from the foramen were also assessed. Data were compared statistically (α = 5%). ResultsThe instruments used at the foramen and 1 mm beyond promoted foraminal enlargement and transportation. Regarding NIW, there was no difference between mechanized foraminal enlargements performed at the foramen or 1 mm beyond, similar to the manual foraminal debridement group (P > .05). There was no difference in transportation and centralization at 1-, 3-, and 5-mm apical levels, regardless of the instrumentation systems. ConclusionMechanical preparation at the foramen, or 1 mm beyond, resulted in foraminal enlargement, transportation and were not able to touch all root canal walls that delimit the foramen.

Reprint of: The Effect of Mineral Trioxide Aggregate Obturation Levels on the Outcome of Endodontic Retreatment: An Observational Study

IntroductionNo clinical studies have examined the effect of mineral trioxide aggregate (MTA) obturation levels on the outcome of endodontic retreatment. This retrospective study examined treatment outcomes in three cohorts that compared overfilling, flush filling, and underfilling after orthograde retreatment using MTA. MethodsTwo hundred fifty patients with 264 teeth diagnosed with previously treated root canals and apical periodontitis retreated in a private endodontic practice were included. All teeth received MTA obturation and the extent of the final filling level was measured in relation to the major apical foramen. After 6-month follow-ups, all nonhealing cases were treated surgically. After 24- to 72-month reviews, the effect of preoperative lesion size and the degree of MTA obturation level were assessed. Multiple linear regression and time-to-event analysis using Stata 17 software (StataCorp LLC, College Station, TX) were used to evaluate the data. ResultsWithin the three cohorts, 99 out of 108 overfilled teeth (91.7%), 90 out of 103 flush fills (87.4%), and 10 out of 53 underfilled teeth (18.9%) healed and were successfully retreated without surgery at 48-months. When surgical outcomes were included, the combined healed proportion was 93.2%. Preoperative lesion size was found to be an important predictor for retreatment nonhealing. A 1-mm increase in lesion size at baseline resulted in an estimated 11% (95% CI 1.04, 1.18)–38% (95% CI 1.22, 1.58) increase in the risk of surgery. Compared to overfilling and flush filling, underfilling was associated with an approximately three-fold increase in requiring surgery and characterized by delayed healing. ConclusionMTA obturation is a viable retreatment option for teeth with nonhealing endodontic treatment. MTA overfills or flush fillings do not adversely affect healing outcomes. However, MTA underfilling increases the chances for nonhealing and surgical intervention.

Morphological Variation of Mandibular Molars in Rohilkhand Population: An Original Research

ABSTRACT Introduction: In-depth knowledge of common and aberrant pulp morphology is essential for appropriate diagnosis and treatment planning before commencing root canal treatment. The radicular morphology of mandibular molars has been extensively studied. Considerable variation in the number of canals and roots found in these teeth has been reported. Aim: The purpose of this study is to investigate the root canal morphology of the mandibular molars among the Rohilkhand population using Dentascan. Materials and Methods: Dentascan images of mandibular molar were taken from 99 extracted teeth that were collected from the Department of Oral Surgery and Maxillofacial Surgery, Institute of Dental Sciences, Bareilly, and private clinics. The examination of root canal systems of the teeth was based on Vertucci’s classification. Results: The mandibular molar (n = 99) were taken. Out of the 99 teeth examined, three canals were seen in 60 (60.6%) teeth, four canals in 39 (39.4%) teeth, 3% had extra distal roots, and 6% with C-shaped canals. Conclusion: Among mandibular first molars, only 3% had three roots. Mesial roots of the first molar typically present with two canals and two apical foramina with type IV or II canal configuration. Most distal roots of the first molar presented with a type I canal configuration. The remainder were distributed mainly between types II, IV, III, and V. Among 99 mandibular molars, 6% had single C-shaped roots.

Morphometric parameters of dental pulp in immature teeth in a sheep model after mechanical pulp exposure and restoration with reinforced zinc oxide-eugenol

Background: The aim of the study was to investigate the morphometric parameters of dental pulp in open apices immature teeth in a sheep model after mechanical pulp exposure and restoration with reinforced zinc oxide-eugenol. Materials and Methods: In this experimental study, a total of 12 immature mandibular central incisors from six adult male sheep, weighing 30–40 kg and with the age of 1 year old with Merino race were examined. After anesthesia, the pulps of the teeth in the case group were mechanically exposed and then were restored with reinforced zinc oxide-eugenol and amalgam. In the control group, the teeth remained intact. The animals were sacrificed at intervals of 2, 4, 6, and 8 weeks (E2, E4, E6, and E8) in the case and 2 and 8 weeks (C2 and C8) in the control groups. Then, their teeth were removed with the surrounding supporting tissues and alveolar bones. Tissue processing and staining were done, and the sections were examined under a light microscope. The Kruskal–Wallis and Mann–Whitney U tests were used to analyze the data and compare the changes between the two groups. P &lt; 0.05 was considered statistically significant. Results: In response to mechanical exposure, reparative or tertiary dentin was formed, and its thickness increased during the time of the study. The thickness of the odontoblastic layer in the E4 group was the highest amount. The pulp chamber diameter in the C2 group was significantly larger than the other groups, and the diameter of the apical foramen in the E8 was decreased significantly compared to the controls (P &lt; 0.05). Conclusion: In response to mechanical exposure and restoration with reinforced zinc oxide-eugenol, some morphometric parameters of the dental pulp changed significantly in the sheep model compared to the controls.

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

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

The Incidence of Two Root Canals in the Mesial Root of the Extracted Permanent Maxillary First Molars Among a Sulaimani-Iraq Population (Ex Vivo Study)

The aim of this study was to assess the incidence of two root canals in the mesial root of the extracted permanent maxillary first molars of a Sulaimani population. An ex vivo study on 180 extracted permanent maxillary first molars was conducted. The teeth were examined clinically and radiographically. The results showed that 23.3 % of the examined teeth had two canals in the mesial root (17.0 % with one apical foramen and 6.3 % with two separate foramens)

Regeneration of the apical region of the tooth after the treatment of destructive periodontitis with cement resorption

Aim. Destructive changes in the tissues of the tooth and periodontium entail resorption of the hard tissues of the tooth in the apical region. The goal is to identify morphological changes in root tissues with destructive periodontitis and resorption phenomena after the treatment of the tooth with calcium-containing preparations using a scanning electron microscope. Materials and methods. Examination of teeth treated for destructive forms of periodontitis with apical resorption was performed using a JSM-6490LV scanning electron microscope (JEOL, Japan) with an energy-dispersive attachment INCA Penta FETx3 (OXFORD Instruments, England). Results. In the apical part of the root there is a cellular mixed layered cementum. The dentin and the dentin-cementum junction are highly calcified. On top of them is cellular cement with lacunae of cementoblasts. The relief of the zone of cell-free cement has a wavy structure, consists of dense collagen fibers with a high content of calcium. With external root resorption, we observe extensive destruction of the cementoblast layer. An area of newly formed cementum was found inside the apical foramen. On the apical surface, where the resorption covered the dentin layer, there was an area of newly formed cementum. Its cellular layer consisted of round-shaped cells rising above the tissue of a homogeneous structure, smoothly flowing into the spongy tissue denting the bone. Discussion. It can be assumed that prolonged use of calcium-containing drugs leads to calcification. The presence of dense connective tissue in the periodontium indicates regenerative processes. The control of cement formation remains uncertain. Conclusions. Perhaps we are seeing a reparative atypical regeneration of the cement of the apical part of the tooth root. Dentinal calcification. In the lateral parts of the apical region, there is an outer layer of cementum with no cementoblasts. An increase in the thickness of the cement was noted. It can be assumed that we observe the phenomenon of osteogenesis in the area of strong resorption.

Allogeneic Bone Marrow Mesenchymal Stromal Cell Transplantation Induces Dentin Pulp Complex-like Formation in Immature Teeth with Pulp Necrosis and Apical Periodontitis

IntroductionDental pulp regeneration is challenging in endodontics. Cellular therapy is an alternative approach to induce dental pulp regeneration. Mesenchymal stromal cells (MSCs) have the capacity to induce dental pulp-like tissue formation. In this study, we evaluated the capacity of allogeneic bone marrow MSCs (BM-MSCs) to regenerate pulp following necrosis and apical periodontitis in children's permanent immature apex teeth. MethodsPatients aged 8 to 12 years with pulp necrosis and apical periodontitis were evaluated. The study included 15 teeth (13 incisors and 2 molars) from 14 patients (8 boys and 6 girls). Radiographic evaluation showed periapical radiolucency and immature apex teeth. There was no response to cold or electric pulp testing. The root canal of each tooth was cleaned, shaped, and Ca(OH)2 used as an interappointment medication. Cryopreserved allogeneic BM-MSCs were thawed, expanded, incorporated into preclotted platelet-rich plasma, and implanted into the tooth's pulp cavity. They were sealed with bioceramic cement and composite. Sensibility, apical foramen, calcium deposits within the root canal, and resolution of periapical lesions were evaluated in each tooth over the following 12 months. ResultsBased on 9 variables established for dental pulp-like tissue regeneration, all MSC-treated teeth showed evidence of successful regeneration. Clinical and radiographic evaluation of the treated teeth showed periapical lesion healing, sensitivity to cold and electricity, decreased width of the apical foramen, and mineralization within the canal space. ConclusionsTransplantation of allogeneic MSCs induces the formation of dental pulp-like tissue in permanent immature apex teeth with pulp necrosis and apical periodontitis. Implant of MSCs constitutes a potential therapy in regenerative endodontics in pediatric dentistry. Future studies incorporating a larger sample size may confirm these results.

Periapical bacterial disinfection is critical for dental pulp regenerative cell therapy in apical periodontitis in dogs

BackgroundApplication of pulp regenerative cell therapy for mature teeth with periapical lesions is a critical clinical challenge. The bacterial infection in inaccessible location within the root canal system and in the periapical lesions could cause resistance and impediment, leading to limitations in successful therapy. Thus, the aim of this study was to examine the effect of residual bacteria on the outcome of pulp regeneration in mature teeth with apical periodontitis in dogs.MethodsPeriapical lesions were induced in 32 root canals of 4 dogs in two different models in severities, model A and model B. Model A (moderate infection): the canal exposed to the oral cavity for 2 weeks and then closed for 2 weeks. Model B (severe infection): the canal exposed to the oral cavity for 2 months and then closed for 5 months. All root canals were irrigated with 6% sodium hypochlorite, and 3% EDTA and further with 0.015% levofloxacin-containing nanobubbles, which was also used as an intracanal medicament. The aseptic conditions were examined by bacterial anaerobic culture and/or PCR analyses. The root canal treatment was repeated several times, and allogeneic dental pulp stem cells were transplanted into the root canals. The radiographic evaluation of periapical lesions was performed by cone-beam computed tomography before the first treatment, just after cell transplantation, and after 2 months and 6 months in both model A, model B, respectively. The animals were then sacrificed and the jaw blocks were harvested for histological and histobacteriological evaluations of pulp regeneration and periapical tissue healing. Furthermore, the DiI-labelled DPSCs were transplanted into the root canals after complete disinfection (n = 4) or without root canal treatment (n = 4) in the apical periodontitis model (model A) in one dog, and cell localization was compared 72 h after transplantation.ResultsIn 8 out of 12 canals from model A, and 10 out of 15 canals from model B, pulp regeneration with good vascularization, innervation, and a significant reduction in the radiolucent area of the periapical lesions were observed. However, in the other 4 canals and 5 canals from model A and model B, respectively, no pulp tissue was regenerated, and inflammation in the periapical tissue, and external resorption or healed external resorption were detected. The presence of residual bacteria in the periapical tissues and severe inflammation were significantly associated with inhibition of regenerated pulp tissue in these 9 unsuccessful canals (P < 0.05, each) (OR = 0.075, each) analyzed by multiple logistic regression analysis. For cellular kinetics, transplanted cells remained in the disinfected root canals, while they were not detected in the infected root canals, suggesting their migration through the apical foramen under the influence of inflammation.ConclusionsA true pulp-dentin complex was regenerated in the root canal by the pulp regenerative therapy in mature teeth with apical lesions. The successful pulp regeneration was negatively associated both with residual bacteria and inflammation in the periapical tissue.