Mandibular Teeth Research Articles

Biomechanical effects of different mandibular movements and torque compensations during mandibular advancement with clear aligners: a finite element analysis

IntroductionThis study aimed to evaluate the biomechanical effects of different mandibular movements and torque compensations during mandibular advancement with clear aligners using finite element analysis.MethodsModels were constructed to include the mandible, teeth, periodontal ligament (PDL), and clear aligners with buccal wings. Five oral muscles (superficial masseter, deep masseter, medial temporalis, posterior temporalis, and medial pterygoid) were represented as springs. Muscle values were measured and applied during different mandibular movements, including advancement distances (1–7 mm) and occlusal opening distances (2–4 mm). Different torque compensation angles (0°, 1°, 2°, and 3°) were applied to the mandibular central incisor.ResultsWhen the mandibular advancement was equal to or slightly excessed the occlusal opening distance, stress on the posterior PDL decreased and became more evenly distributed. Increasing the occlusal opening distance significantly raised stress on the posterior PDL and caused grater labial inclination of the mandibular anterior teeth. As the torque compensation increased, the labial inclination of the mandibular central incisor decreased, but stress on the PDL increased. Nearly complete bodily movement of the lower central incisor was achieved with torque compensation angles of approximately 15°, 19°, and 20° in models M1-2, M2-3, and M3-4, respectively.ConclusionTo maintain periodontal health during mandibular advancement, it is recommended that the mandibular advancement distance be equal to or slightly excessed the occlusal opening distance. Excessive occlusal opening distance increases stress on the posterior PDL and the labial inclination of mandibular anterior teeth, requiring careful control. Additionally, proper torque control of the mandibular interior teeth is crucial for optimal outcomes.

Evaluation of Preclinical Class I Amalgam Cavity Preparation: A Comparison of Two Assessment Methods

Preclinical assessment forms an effective strategy in undergraduate training. It enhances the continuous development of skills, facilitates early intervention, and optimizes training resources. Constructive feedback provided to the student fosters continuous improvement in preparedness for professional practice and has implications for the development of a learning culture characterized by student activity. This indeed ensures that a smooth transition will be made toward clinical application of skills. The aim of the study was to evaluate examiner`s reliabilities while applying two different assessment methods: a Glance and Grade assessment method and a Checklist and Criteria assessment method. A total of 100 class I amalgam cavity preparations were assessed by three independent examiners to evaluate Class I amalgam cavity preparations on artificial first mandibular molar teeth prepared by second-year undergraduate dental students in a preclinical laboratory setting. Statistical analysis for inter-examiner and intra-examiner variability was tested using one-way ANOVA test and a paired t-test, respectively. Results of this study showed that intra-examiner variability was significantly reduced with Checklist and Criteria assessment method. The inter-examiner variability was present in a Glance and Grade assessment method while with the Checklist and Criteria assessment method, there was an extremely high level of agreement among the examiners. The study's findings indicated considerable variability among examiners using the Glance and Grade assessment method. However, the Checklist and Criteria assessment method demonstrated remarkable consistency among examiners, indicating that it may offer a more standardized and reliable approach to evaluation.

Traumatic Dental Injuries in Children and Adolescents from a Major Dental Clinic in Bosnia and Herzegovina: A 5-Year Retrospective Study

The aim of this study was to investigate the epidemiology of dental trauma in a public dental clinic in Banja Luka, Bosnia and Herzegovina, from 2019 to 2024. Methods: This research was conducted as a retrospective cross-sectional study. The data were analysed and compared between injured primary and permanent maxillary and mandibular teeth. Results: The review of the dental records revealed 73 patients (49 boys and 24 girls) with TDIs, involving 55 primary and 64 permanent teeth. Most of the patients (27 patients, 36.98%) were aged 7–9 years. The main cause of TDI was falls in both dentitions (81.81% of injured primary teeth and 73.43% of injured permanent teeth). The time of arrival after a TDI for assistance in the dental clinic for most cases was after 24 h in both dentitions, 45.45% of injured primary teeth and 48.43% of permanent teeth. For both dentitions, enamel fractures were the most common injury of hard dental tissues and the pulp, and the necrosis of the maxillary central incisor was the most common complication. Conclusions: It is very important to improve trauma management and increase public knowledge on the way parents seek proper treatment for the TDIs of their children, and in due time.

CBCT Guidance for Removing Foreign Object from the Jawbone: A Case Study

AbstractForeign objects lodged in the mandibular bone often result from trauma or dental procedures. Accurate localization of these foreign objects is crucial for guided surgical removal, especially when patients present with persistent pain. Conventional imaging modalities like periapical and panoramic radiographs may not provide sufficient detail for precise localization. Cone beam computed tomography (CBCT) has emerged as a valuable tool for guided surgical interventions owing to its superior imaging capabilities. We present two cases of foreign objects lodged in the mandible, where patients complained of prolonged pain, soreness, and numbness in the right mandible extending to the head and behind the ear. Both patients had undergone previous right mandibular tooth extractions and received treatment from a neurologist without resolution of symptoms. Both cases showed the control improvement in complaints, and no paresthesia or postoperative complications were found. CBCT-guided surgical removal was performed in both cases, revealing a metal specimen measuring 6 × 3 × 1 mm3 in the first patient and a remaining root measuring 5 × 3 × 2 mm3 in the second patient. Diagnosing foreign objects in the mandible poses challenges due to their varied size, composition, and proximity to vital structures. CBCT offers superior imaging resolution, enabling precise localization and assessment of anatomical relationships, such as the distance to the inferior alveolar nerve and surrounding boundaries. CBCT emerges as the preferred imaging modality for diagnosing and guiding the surgical removal of foreign objects in the mandible. Its advantages include accurate localization, low radiation exposure, and cost-effectiveness. Compared with CT scans, CBCT also offers faster scanning times, making it a valuable tool in clinical practice for managing such cases

"Effect of mid-root perforation and its repair on stress distribution and fracture resistance: a 3D finite element analysis and in vitro study".

to assess and compare the effect of mid-root perforation repair using Biodentine and Portland cement in single-rooted endodontically treated mandibular premolars in terms of stress distribution using finite element analysis (FEA) and fracture resistance test. In the FEA, an extracted human mandibular premolar tooth was scanned using cone beam computed tomography, and a 3-dimensional (3D) solid model was created. A sound tooth model (ST), an endodontically treated model (ET), an instrumented and mid-root perforated and repaired by Biodentine model (BM), and perforated and repaired by Portland cement model (PCM) were the 4 models simulated. A vertical force of 300N on the occlusal plane was applied. Evaluation of von Mises stress distribution and maximum displacement were investigated. In the fracture resistance in vitro study, 28 extracted premolars were selected and randomized into 4 groups, (n = 7), (A) is the negative control intact group, (B) is the positive control of endodontically treated group, (C) is mid-root perforated and repaired by Biodentine group and (D) is mid-root perforated and repaired by Portland cement. All Teeth were instrumented except for group A, group B was obturated while groups C and D were instrumented, perforated, repaired, and obturated. All groups were restored coronally except group A. Fracture force was measured; subsequently, the fracture repairability was evaluated. Finally, the data were statistically evaluated using one-way analysis of variance (ANOVA); the significance level was set at P ≤ 0.05 and the repairability of teeth after fracture was correlated to the maximum loading using Pearson's coefficient tests. In FEA, Maximum von Mises stress was descending assorted as 121.1MPa for ET, 115.6MPa for BM and PCM, and 109MPa for ST, and in the mid-root area or perforation site were 20MPa for PCM, 16.17MPa for BM, 10.16MPa for ET and 8.1MPa for ST while the Maximum Displacement was descending assorted as 0.0179mm for ET, 0.0169mm for BM and PCM and 0.0151mm for ST. In the fracture resistance test, Group A showed higher fracture resistance than other groups significantly. There was a non-significant difference between Groups B, C, and D. There was also an insignificant correlation between the maximum loading and the repairability of the tooth after fracture. FEA and fracture resistance test showed that the 2 repair materials are acceptable and recommended in iatrogenic mid-root perforation.

Automated dentition segmentation: 3D UNet-based approach with MIScnn framework

Advancements in technology have led to the adoption of digital workflows in dentistry, which require the segmentation of regions of interest from cone-beam computed tomography (CBCT) scans. These segmentations assist in diagnosis, treatment planning, and research. However, manual segmentation is an expensive and labor-intensive process. Therefore, automated methods, such as convolutional neural networks (CNNs), provide a more efficient way to generate segmentations from CBCT scans. A three-dimensional UNet-based CNN model, utilizing the Medical Image Segmentation CNN framework, was used for training and generating predictions from CBCT scans. A dataset of 351 CBCT scans, with ground-truth labels created through manual segmentation using AI-assisted segmentation software, was prepared. Data preprocessing, augmentation, and model training were performed, and the performance of the proposed CNN model was analyzed. The CNN model achieved high accuracy in segmenting maxillary and mandibular teeth from CBCT scans, with average Dice Similarity Coefficient values of 91.83% and 91.35% for maxillary and mandibular teeth, respectively. Performance metrics, including Intersection over Union, precision, and recall, further confirmed the model's effectiveness. The study demonstrates the efficacy of the three-dimensional UNet-based CNN model within the Medical Image Segmentation CNN framework for automated segmentation of maxillary and mandibular dentition from CBCT scans. Automated segmentation using CNNs has the potential to deliver accurate and efficient results, offering a significant advantage over traditional segmentation methods.

Copper Oxide Nanoparticles Loaded in Adhesive to Carious Dentin. An In Vitro Study Assessing μTBS, Degree of Conversion, EDX, and SEM

This In Vitro study investigated the effects of incorporating copper nanoparticles (CuNPs) into an etch-and-rinse (ER) adhesive on the survival rate of Streptococcus mutans (S. mutans), micro tensile bond strength (μTBS), and degree of conversion (DC) when applied to carious dentin. Mandibular teeth with carious lesions were selected, and S. mutans was inoculated on carious-affected dentin (CAD). The samples were divided into four groups based on the concentration of CuNPs in the OptiBond FL primer: Group 1 had unmodified ER adhesive, Group 2 had 0.1 wt% CuNPs, Group 3 had 0.5 wt% CuNPs, and Group 4 had 1 wt% CuNPs. The survival rate of S. mutans was assessed, and the samples were restored to evaluate μTBS and failure modes. The DC was measured using Fourier Transform Infrared Spectroscopy (FTIR). Statistical analysis using ANOVA and Tukey tests determined significant differences across groups in antibacterial efficacy, μTBS, and DC. The results indicated that the 1 wt% CuNPs group (Group 4) exhibited the lowest bacterial survival, while the unmodified ER adhesive group (Group 1) showed the highest S. mutans survival. The highest bond strength to the CAD was observed in the 0.5 wt% CuNPs group (Group 3), with Group 1 demonstrating the lowest μTBS. These findings suggest that incorporating CuNPs into an ER adhesive system, particularly at a concentration of 0.1 wt%, can effectively provide antimicrobial properties to the adhesive interface while simultaneously enhancing bond strength and achieving a favorable degree of conversion with carious-affected substrates.

Periapical cemento-osseous dysplasia masquerading as asymptomatic chronic apical periodontitis in a Chinese woman: A case report.

Cemento-osseous dysplasia (COD) belongs to a group of fibrous osseous disorders that can masquerade as periapical inflammatory conditions in the jawbones. We present a rare case of COD occurring in a patient who also had periapical periodontitis concurrently. When faced with a patient exhibiting no symptoms, diagnosis may be challenging. COD is a fibrous osseous disorder similar to periapical chronic inflammatory conditions and other cysts in the jaw bones on the radiograph. There is a rare case of COD occurring in a 49-year-old Chinese woman who also had chronic periapical periodontitis concurrently. The lesions were incidentally discovered in the mandibular anterior tooth region during the patient's imaging examination. The patient exhibited no symptoms, and diagnosing the conditions may be challenging due to the confusingly similar radiological features that present as a radiolucent lesion in the periapical region. The final diagnosis was made through pulp vitality tests, cone beam computed tomography (CBCT), and clinical examinations. The COD was recommended for annual follow-up. Root canal therapy has been performed for chronic apical periodontitis. According to the diagnostic process of COD, a thorough history check, multiple clinical examinations, and imaging studies should be emphasized to prevent misdiagnosis and avoid unnecessary or inappropriate therapies. The patient was followed up for 6 years. The recovery of chronic apical periodontitis in tooth #31 and the transformation of osteolytic and osteogenesis of COD had been observed in CBCT.

Diagnosis and endodontic treatment of odontogenic cutaneous sinus tracts: A report of two cases

Introduction: The odontogenic cutaneous sinus tract (OCST), caused by pulp necrosis, creates connections between pathological spaces and anatomical structures. Extraoral manifestations pose diagnostic challenges leading to inappropriate treatments such as multiple surgery and antibiotic therapies. Effective management requires the treatment of dental pathology through endodontic therapy or extraction. This paper presents two cases of OCST and emphasizes the importance of accurate diagnosis and successful non-surgical endodontic treatment. Observations: Case report 1: A 23-year-old male patient referred by his dermatologist with a cutaneous sinus tract on his chin that had appeared five years ago. During this period, he reported spontaneous pain and pus discharge from the chin area. The examination revealed a periapical lesion associated with tooth number 31. Cone beam computed tomography (CBCT) revealed the existence of a localized perforation on the buccal alveolar table and a second root canal of the tooth. After six months of follow-up, the cutaneous sinus tract was significantly improved by the appropriate endodontic treatment. Case report 2: A 36-year-old female patient was referred by her dentist to examine a chin lesion that had appeared a month ago. In clinical examination and radiographic assessment, periapical lesion associated with two mandibular central incisor teeth #41 and #31 was observed. After identifying the source of infection, endodontic treatment was carried out, and a good improvement in fistula was observed after one month. Conclusions: The correct diagnosis and treatment of OCST are important for healing. CBCT aids to identify odontogenic origin of the sinus tract through the detection of apical periodontitis and bone lesion. Root canal therapy is the treatment of choice for these cases and should always be attempted first. Monitoring the patients is necessary until complete healing of the disease.

Photomechanical investigation on the impact of endodontic cavity design on the biomechanical response in mandibular posterior teeth

The traditional endodontic cavity (TEC) facilitates canal preparation, but may increase susceptibility to root fracture; conservative endodontic cavities (CEC) aim to preserve tooth structure to maintain the structural integrity of root-filled teeth. The objective of this study was to evaluate the effect of access cavity design and the degree of pulp chamber roof removal on the microstrain distribution patterns under different levels of functional loading using digital moiré interferometry (DMI). Twelve extracted human teeth (N=12) were included, comprising of mandibular premolars (n = 6) and mandibular first molars (n = 6). Specimens were subjected to physiologic levels of compressive loading ranging from 10 to 50N for each group. DMI fringe patterns were acquired three times for each pecimen: prior to endodontic cavity preparation (control group (CG)), after conservative endodontic cavity preparation (CEC), and following traditional endodontic cavity preparation (TEC). The acquired fringe patterns were used to determine the microstrain distribution at the coronal and cervical dentin. The data was analyzed qualitatively and quantitatively using one-way ANOVA and T-tests (P< 0.05). The intact crowns of CG teeth showed significantly less microstrain, when compared to CEC and TEC with a distinct shift in coronal microstrain in both CEC and TEC groups. There were significant differences between both the coronal and cervical microstrain in the CG, CEC, and TEC groups. The roof of the pulp chamber contributes to a distinct biomechanical response in posterior teeth. The microstrain at the coronal and cervical level increased significantly following de-roofing of the pulp chamber in both CEC and TEC groups, with the TEC resulting in higher coronal microstrain compared to CEC group.

Evaluation of Cold and Electric Pulp Tests for Assessing the Success of Inferior Alveolar Nerve Block for Mandibular First Molars diagnosed with Symptomatic Irreversible Pulpitis

IntroductionFear of dentistry, often due to past painful experiences, is a significant barrier preventing patients from visiting dentists. Achieving effective pain control, especially during root canal treatments, is crucial. However, inferior alveolar nerve blocks (IANB) have a low success rate, influenced by factors such as anxiety, anatomical variations, and technique limitations, leading to anesthesia failure. Although numerous studies have examined the cold test and EPT in assessing the success of local anesthesia, no standardized method has been established. This study evaluated the effectiveness of electric pulp test (EPT) and cold tests in assessing the depth of anesthesia in patients with symptomatic irreversible pulpitis (SIP) in the mandibular first molar teeth. MethodsA cross-sectional study was conducted on 50 patients with SIP who met the inclusion criteria and exhibited lip numbness. Following the administration of the IANB and confirmation of lip numbness, cold tests and EPT were performed on all patients. Subsequently, the preparation of the access cavity (gold standard test) was initiated, and patients' responses during cavity preparation were recorded as either "presence of pain or discomfort" or "absence of pain or discomfort," indicating IANB failure and success, respectively. Sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), positive and negative likelihood ratios (LR-/+), and accuracy (AC) with 95% confidence intervals (CI) were calculated for each test separately as well as for sequential testing. ResultsIANB failure was determined in 56% of the patients. A comparative analysis of diagnostic tests (cold test and EPT) showed no significant difference in SN, NPV, and AC; however, the cold test had higher SP, PPV, and LR+. Combining cold test and EPT evaluations improved SN, NPV, PPV, and LR-, but SP and AC were similar to EPT alone. No correlation was found between IANB success and patient age, sex, or initial pain. ConclusionsDespite evidence of lip numbness, a significant number of IANBs failed in cases of painful pulpitis. A positive result from the cold test strongly indicated anesthesia failure. The findings of the current study suggested that when the cold test yielded a negative result, further evaluation with EPT was necessary to confirm anesthetic success and ensure complete pain control.

Relationship between orthodontic treatment and bone densit

The aim of this study is to examine the change in bone density around the apex of mandibular anterior teeth in groups formed based on malocclusion types after orthodontic treatment. A total of 18 individuals were included in the study, grouped according to malocclusion types (Class I, Class II, and Class III). This retrospective study analyzed the bone density around the apex of mandibular anterior teeth using fractal analysis on panoramic images. Bone density increased around the apex of mandibular anterior teeth in individuals with Class I, Class II, and Class III malocclusions after orthodontic treatment. Statistically significant differences were found in the change of bone density before and after orthodontic treatment among the malocclusion groups. The greatest change in bone density was observed in the Class III group, while the least change was in the Class I group. The fractal analysis method is a technique that facilitates the diagnosis of minimal changes occurring in patients undergoing orthodontic treatment. Potential changes in teeth and adjacent tissues should be carefully evaluated, and orthodontic treatments should be planned in accordance with these evaluations.

Sealing Ability of Bioceramic Sealer after Ultrasonic Activation of Different Root Canal Irrigating Solutions

Aim To evaluate and compare the sealing ability of bio ceramic root canal sealer after ultrasonic activation of root canal irrigation solutions 3% NaOCl , 40% Citric acid &amp; Neem leaf extract .  Materials and Methods In this study, 42 mandibular premolar teeth with single roots and canals were divided into three groups for irrigation: 3% NaOCl, 40% citric acid, and Neem leaf extract. After access preparation and glide path creation with a #10 K-file (0.02 taper), the canals were instrumented using a crown-down technique to an ISO size of 30, with saline as the irrigant. Ultrasonically activated irrigation was used, followed by saline in all groups. The canals were obturated with Dentsply Gutta- percha and Bio C sealer, 1mm short of the working length, and sealed with temporary restorations. Teeth were incubated at 37°C for 3 days, and horizontal sections at 3mm from the apex were taken. Confocal laser scanning microscopy measured sealer penetration, and statistical analysis was conducted to compare results between groups.  Results The results suggest that 40% citric acid is the most effective irrigant for enhancing sealer penetration into dentinal tubules at the apical third, both in terms of percentage and depth of penetration, compared to 3% NaOCl and neem leaf extract. This indicates that citric acid may improve the sealing ability of root canal treatments more effectively than the other tested irrigants.  Conclusion The results suggest that 40% citric acid is the most effective irrigant for enhancing sealer penetration into dentinal tubules at the apical third, both in terms of percentage and depth of penetration, compared to 3% NaOCl and neem leaf extract. This indicates that citric acid may improve the sealing ability of root canal treatments more effectively than the other tested irrigants.

Evaluation of Injectate Distribution of the Middle Mental Nerve Block Within the Mandibular Canal in a Cadaveric Canine Model.

Awareness among veterinarians has increased regarding the need for comprehensive pain relief, but many companion animal veterinarians do not administer regional analgesia pre-emptively during dental procedures. The middle mental nerve (MMN) block desensitizes the ipsilateral mandibular incisor and canine teeth as well as soft tissues rostral to the delivery site. There is little published information on the efficacy of the MMN block in dogs. The objective of this study was to determine injectate distribution within the mandibular canal using a radiopaque contrast media/methylene blue solution. Half a milliliter of solution was injected within the opening of the middle mental foramen using a standard hypodermic syringe and a 25G x 25 mm needle. The course of the injectate was traced both via computed tomography (CT) and, in some cadavers, gross dissection. Post-treatment CT revealed that in 90% of the cases, the contrast diffused at least as far caudally as the mesial root of the third premolar tooth. The injectate was not identified within the canal of 5% of cadaveric mandibles examined. Although the solution used diffused caudally within the mandibular canal when injected using recommended clinical techniques, this may not completely represent the extent of clinical effects experienced in live patients. This technique also confirmed that the needle does not need to be advanced into the mandibular canal to achieve adequate diffusion to at least the mesial root of the third premolar tooth.

Effect of loading angle and fabrication materials on stress distribution with periodontal splint in compromised periodontal tissues: a finite element study

Objective: To evaluate the effect of polyetheretherketone (PEEK) periodontal splints and splints made from other materials under static loading on stress distributions in periodontal tissues, cement layer, and splints themselves. Methods: A finite element model based on cone-beam CT imaging data of a 25-year-old male patient (treated at the Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University in October 2021 for a cracked maxillary molar) with a healthy and intact mandibular dentition and periodontal health was constructed. The finite element model included anterior mandible dentition, mandibular bone model without bone resorption (WBR group), a periodontally compromised mandible model (control group), and three types of periodontal splints: a PEEK periodontal splint (0.7 mm thick, Young's modulus: 4.1 MPa), a fiber-reinforced resin (FRC) splint (1.0 mm thick, Young's modulus: 37.0 MPa), and a titanium splint (1.2 mm thick, Young's modulus: 110.0 MPa). The bone resorption models fixed with different periodontal splints constituted the experimental groups (PEEK group, FRC group and titanium group). Loading of 100 N was applied on the midpoint of the incisal edge of tooth 41. The direction was set at 0°, which was parallel to the long axis of the tooth and downward. The buccal to lingual and downward angles were 30°and 60°, respectively, perpendicular to the long axis of the tooth and 90° to the lingual side. The finite element analysis software was utilized to analyze the stress distribution characteristics of the periodontal tissues, adhesive layer, and the splint itself in the anterior mandibular teeth among the different group. Results: Under the different loading simulation, in the control group, the maximal von Mises stresses of periodontal ligament and bone were 15.7-50.2 MPa and 38.8-130.3 MPa, respectively, and in the WBR group, the maximal von Mises stresses of periodontal ligament and bone were 3.6-6.4 MPa and 16.5-42.7 MPa, respectively. Under the same loading conditions, the magnitude of maximal von Mises stresses in periodontal tissues in the PEEK group was 4.6-6.2 MPa, and the magnitude of stresses in the periodontal ligament of 41 teeth in the WBR group was similar to that in the PEEK group, but higher than that in the FRC and titanium groups. The maximal von Mises stresses of each group is primarily distributed in the periodontal ligament and alveolar bone at the cervical area of the tooth. The higher the elastic modulus of the splint, the higher its own maximal von Mises stresses, and the smaller the maximal principal stresses transmitted to the adhesive layer. In the PEEK group and titanium group, the stress distribution area in the adhesive layer and the splint was near the splint connection adjacent to tooth 41. Conclusions: Periodontal splints fabricated from three types of materials, are effective in distributing stress within the periodontal tissues of the abutment teeth. Compared to FRC and titanium group, the higher PEEK splint stress value was obtained, and the smaller the stress value was transmitted to its adhesive layer.

Comparative Study of Pyogenic Granuloma Management with Conservative Sclerotherapy to Invasive Surgical Excision: A Randomized Clinical Trial

Introduction: Pyogenic granuloma is a common benign reactive mucocutaneous lesion. Various treatment options like excision, sclerotherapy, cryotherapy, laser is widely practiced. Objective: This study was conducted to determine and compare the effect of 3% sodium tetradecyl sulfate to surgical excision in the management of oral pyogenic granuloma. Methods: The prospective randomized controlled trial was conducted among two equal randomly allocated groups (48 each) of histologically confirmed cases. Group A was treated by surgical excision while group B was treated by 3% STDS. Both groups were evaluated weekly for a month for pain and healing and 1st, 3rd &amp; 6th for recurrence. Results: Pain score is statistically significant on 1st and 2nd week follow up. No clinical and statistical difference observed in pain on 3rd and 4th week. Clinically significant recurrence was observed in group ‘A’ (4.1%) than group ‘B’ on 3 months but was statistically insignificant. 1 recurrence was observed in group ‘B’ on 6 months whereas, 3 were reported from group ‘A’ in the same duration. Healing on 1st and 2nd weeks were comparable and statistically significant in both groups however the results failed to show any significant difference on 3rd and 4th week. The demographics showed mean age 30.97±12.4 years with 60.42% of incidence in female and the commonest site being mandibular anterior teeth (25%). Conclusion: Although, surgical excision is commonly practiced, it is associated with higher recurrence, increased pain score &amp; prolonged healing period. On contrary, sclerotherapy with 3% STDS proved to be safer, minimally invasive and more accepted by patients with minimum postoperative morbidity.

Enhancing sports mouthguards with PLA + and PC: stress reduction, energy absorption, and topology optimization.

The objective of this paper was to compare the effectiveness of different materials for mouthguards in preventing oral and maxillofacial injuries during sports activities. The present study compares the stress-reduction and energy absorption capabilities of two other fused filament materials - poly(lactic-acid plus) (PLA+) and polycarbonate (PC), with Ethylene-vinyl acetate (EVA), which is the most commonly used material for mouthguard fabrication. Two human skulls were modelled, and a boxing glove simulated punches along the x, y, and z-axes with 5mm displacement with 1 kN force. Firstly, the maximum principal stress curve in the skull was compared for forces along the three perpendicular directions. Furthermore, the present study examines materials energy absorption properties, including their specific energy absorption characteristics and initial peak von Mises stresses. Additionally, a topology optimization approach is used to create an alternative design for a mouthguard to improve specific energy absorption. The model without a mouthguard showed the highest stress concentration of 32.298MPa in the teeth, followed by the EVA material, which resulted in a maximum principal stress of 28.525MPa. Fused filament 3D materials, such as PLA + and PC, on the other hand, showed better mechanical effectiveness in both lower jaw dislocation and lower maximum principal stress by 30.82% and 51.25% in the mandibular and maxillary teeth. Though EVA comparatively shows better specific energy absorption capability at 2.24kJ/kg post-optimization than PLA + and PC, the peak principal stress experienced in the mandibular region was comparatively higher. The topology optimization, however, improved the energy-absorbing capabilities of PLA + by 4.5 times, reaching 1.37kJ/kg and PC from 0.165kJ/kg to 0.38kJ/kg. This study demonstrates that PLA + and PC have better stress reduction capabilities than EVA and could be promising materials for the fabrication of mouthguards in sports activities. This study highlights the importance of topology optimization in dental materials science and engineering to develop safer and more effective mouthguard designs.

Influence of sonic activation of epoxy-resin and calcium silicate sealer on postoperative pain: a patient-blinded, parallel group, randomized clinical trial

BackgroundThis clinical study aims to compare postoperative pain after single-visit root canal treatment of teeth with asymptomatic apical periodontitis using epoxy-resin-based AH Plus and calcium silicate-based Endosequence BC sealers with or without sonic activation.MethodsThis study included 72 individuals with one first or second mandibular premolar tooth with asymptomatic apical periodontitis. They were randomly divided into four groups according to the root canal sealer (AH Plus or Endosequence BC) and activation protocol (sonic activation or non-activation) (n = 18). The participants were ask to rate their postoperative pain intensity on a NRS scale as none, minimal, moderate, or severe after 24 h, 48 h, 72 h, and 7 days following treatment. Patients were also asked to record the number of prescribed analgesic medication tablets (400 mg of ibuprofen) taken. Statistical analysis were performed using the Mann-Whitney U test, the Friedman test, the Spearman’s correlation test, the Chi-square test. Significance level was established at 0.05.ResultsThere was no statistically significant difference in postoperative pain scores or analgesic intake between AH Plus and Endosequence BC sealers regardless of the activation protocol (p > 0.05). There was no statistically significant difference in postoperative pain scores between the sonic activation and non-activation groups (p > 0.05). A weak positive correlation was detected between Endoactivator sonic activation and sealer extrusion (r = 0.36).ConclusionsAH Plus and EndoSequence BC root canal sealers showed similar results in terms of prevalance and intensity of postoperative pain. Sonic activation and non-activation groups had similar postoperative pain scores.Clinical trial registrationThe study was retrospectively registered with ClinicalTrials.gov (NCT06403293). Date of Registration: 07/05/24.

Evaluation of anterior teeth crown-root morphology and alveolar bone structure in patients with closed deep overbite using cone beam computed tomography

This retrospective study used cone-beam computed tomography to investigated the crown-root morphology and alveolar bone structure in incisors region in subjects with closed deep overbite and comparison the difference between gender and age. The CBCT images for 40 subjects (group C) with Angle II division 2 were selected from patients of the HeFei Stomatological Hospital from November 2023 to March 2024.20 individual normal occlusion subjects (group A),20 patients with Angle II division 1(group B) were included. The crown-root ratio of the maxillary and mandibular anterior teeth, crown-root angle and alveolar bone structure were measured on the CBCT images, the data were statistically analyzed. In addition to mandibular lateral incisor, the crown-root ratio of maxillary and mandibular anterior teeth in the Class II division 2 group was higher than that in the individual normal occlusion group and the Class II division 1 (P < 0. 05). The crown-root angle of maxillary anterior teeth in the Class II division 2 group was smaller than that in the individual normal occlusion group and the Class II division 1 (P < 0. 05). The alveolar bone thickness of the maxillary central incisor was comparatively smaller, while the alveolar bone height was relatively higher in the Class II division 2 group. Age and gender were associated with change in root lengths and crown-root angle for the Class II division 2 group (P < 0. 05). Patients with closed deep overbite malocclusion exhibit a significant difference compared to the controls for most measurements. The patients presenting with Class II division 2 malocclusion exhibit excessive inward positioning of the anterior teeth, resulting in evident crown-root angle, a large crown-root ratio, and minimal labial alveolar bone. In order to keep the tooth movement within the safe range of alveolar bone movement, it is necessary to strictly control the torque and use appropriate orthodontic force to reduce the risk of bone fenestration, bone dehiscence, gingival recession and root resorption.

Evaluation of External Apical Root Resorption in Cases with Extraction and Non-Extraction Fixed Orthodontic Treatment.

The objective of this study was to evaluate external apical root resorption (EARR) in cases with extraction and non-extraction fixed orthodontic treatment. Ninety subjects were included in this study. The patients were divided into two groups: 43 with extraction treatment and 47 with non-extraction orthodontic treatment. EARR was measured using the crown-to-root ratio of the maxillary and mandibular incisors and canines on panoramic radiographs taken at the beginning (T0) and end of the treatment (T1). The Bonferroni corrected Z test was used for multiple comparisons. There were 24 (55.8%) individuals in the extraction group and 12 (25.5%) in the non-extraction group, with a minimum of one tooth with severe resorption. There was no resorption in 0% of individuals in the extraction group and five (10.6%) individuals in the non-extraction group. There was a statistically significant correlation between the groups and the degree of resorption (p = 0.008). When the maxillary and mandibular teeth in the extraction group were compared, a significant difference was found in all degrees of resorption except for mild resorption. There was a significant difference in EARR between the extraction and non-extraction treatment groups, with maxillary incisors showing more resorption in the extraction treatment.