Regenerative Endodontic Procedures with Minced Pulp Tissue Graft in Mature Permanent Teeth: A Clinical study.

INTRODUCTION: Regenerative endodontic procedures (REPs) using cell-based approaches have emerged as novel treatment modalities. This clinical study aimed to present the outcomes and explore factors influencing REPs with minced pulp tissue (MP) grafts in a mature tooth. METHODS: Six healthy male patients aged 20-27 requiring non-surgical root canal treatment were enrolled in this study. MP tissue obtained from third molars was introduced into the instrumented, disinfected, and blood-filled root canal. The canal was sealed with bioceramic cement, and the coronal access cavity was restored. RESULTS: Follow-ups for six cases ranged from 19 to 42 months. Radiographically, all the teeth showed favorable outcomes. Among the six teeth, two showed neither intracanal calcification nor recovery in sensibility tests, and one had no intracanal calcification with an inapplicable sensibility test evaluation. In two teeth, intracanal calcification was observed in the apical third; however, there was no recovery in the sensibility tests. One tooth exhibited intracanal calcification in the apical third and showed recovery in the sensibility tests. Considering these outcomes and clinical variables, the size of the apical foramen and the composition of the transplanted pulp tissue were identified as tentative influencing factors. CONCLUSIONS: This study on simplified cell-based therapy using autologous MP for pulp/dentin regeneration in adult teeth not only enhances our understanding of REPs but also suggests its potential as an alternative treatment option to conventional endodontic treatment.

Application of Minimally Invasive Prosthodontics With an Esthetic 16-Unit Rehabilitation of the Dental Arches for a Patient With Anterior Dental Crowding and a Relatively Deep Bite: A Case Report.

Minimally invasive dentistry indicates an operative intervention to correct or manipulate a dental anomaly or lesion while focusing on preserving the original tissues as much as possible. Losing teeth or teeth loss is one of the most common problems patients have always suffered from due to different reasons, such as caries, trauma, or periodontal problems. In cases of multiple teeth loss, oral rehabilitation is usually indicated. Aesthetic reconstruction of a patient's mouth with crowded teeth and a deep bite is challenging for prosthodontists. This case report shows an applicable conservative approach of minimally invasive dentistry in this situation while maintaining vertical dimension and centric occlusion.

Automatic feature segmentation in dental panoramic radiographs.

OBJECTIVE: The purpose of the present study was to verify the diagnostic performance of an AI system for the automatic detection of teeth, caries, implants, restorations, and fixed prosthesis on panoramic radiography. METHODS: This is a cross-sectional study. A dataset comprising 1000 panoramic radiographs collected from 500 adult patients was analyzed by an AI system and compared with annotations provided by two oral and maxillofacial radiologists. RESULTS: A strong correlation (R > 0.5) was observed between AI perception and observers 1 and 2 in carious teeth (0.691-0.878), implants (0.770-0.952), restored teeth (0.773-0.834), teeth with fixed prostheses (0.972-0.980), and missing teeth (0.956-0.988). DISCUSSION: Panoramic radiographs are commonly used for diagnosis and treatment planning. However, they often suffer from artifacts, distortions, and superimpositions, leading to potential misinterpretations. Thus, an automated detection system is required to tackle these challenges. Artificial intelligence (AI) has revolutionized various fields, including dentistry, by enabling the development of intelligent systems that can assist in complex tasks such as diagnosis and treatment planning. CONCLUSION: The automatic detection by the AI system was comparable to oral radiologists and may be useful for automatic identifications in panoramic radiographs. These findings signify the potential for AI systems to enhance diagnostic accuracy and efficiency in dental practices, potentially reducing the likelihood of diagnostic errors caused by unexperienced professionals.

Effects of porcelain layer thickness and luting resin cement on the opalescence properties of porcelain veneers.

BACKGROUND: When discolored teeth are repaired with porcelain veneers, the thickness of the restorations should be increased appropriately using opaque porcelain and bonded by applying opaque luting resin cement to cover discolored substrates. However, its impact on the opalescent performance has not been reported yet. PURPOSE: To analyze the effects of opacity, body porcelain layer thickness, and luting resin cement on the opalescence properties of porcelain veneer restorations for discolored teeth. METHODS: Ninety IPS d. SIGN A3 porcelain veneer specimens were prepared via powder-paste coating and sintering. Specimens were divided into three groups according to ceramic type and cement used or not: body porcelain group as control, body/opaque porcelain group and body/opaque porcelain-resin cement composite group. Each group was subdivided into three subgroups based on the thickness, 0.50, 0.75, and 1.00 mm (n = 10). Variolink N Bleach XL luting resin cement with thickness of 0.1 mm was applied to the bottoms of body/opaque porcelain specimens to produce body/opaque porcelain-resin cement composites. The opalescence (OP) values were calculated and the micromorphological characteristics were analyzed by scanning electron microscope (SEM). Statistical analysis was performed by using ANOVA test (P < 0.05). RESULTS: The opalescence values determined for the body porcelain groups with thicknesses of 0.50, 0.75, and 1.00 mm and body/opaque porcelain specimens with thicknesses of 0.45/0.05, 0.70/0.05, and 0.95/0.05 mm were 3.35 ± 0.15, 3.83 ± 0.10, 6.73 ± 0.25, 7.95 ± 0.34, 15.16 ± 0.60, and 16.49 ± 0.89, respectively. The specimens in the body and body/opaque porcelain groups exhibited significant increases in their opalescence values with increasing thickness (P = 0.00). The opalescence values of the specimens increased significantly with the addition of a 0.05 mm opaque porcelain layer (P = 0.00). The opalescence values of the composites containing body/opaque porcelain layers with thicknesses of 0.45/0.05, 0.70/0.05, and 0.95/0.05 mm and luting resin cement were 9.46 ± 0.17, 16.47 ± 0.15, and 18.38 ± 0.47, respectively. The opalescence values of the composite specimens increased significantly with an increase in the thickness of the porcelain layer(P = 0.00). CONCLUSIONS: The opaque porcelain layer and opaque resin cement can significantly improve the opalescence properties of porcelain laminate veneers for discolored teeth, but the opalescence performance is still poor than natural teeth. The body porcelain only contributes to opalescence within a certain thickness range.

Effect of endodontically treated teeth on prosthetically guided orthodontics with clear aligners: a case series.

BACKGROUND: Prosthetically guided orthodontics (PGO) can correct the malocclusion for better prosthetic rehabilitation in esthetic rehabilitation. Unlike conventional orthodontic treatment, only minor tooth movement is designed in PGO according to the requirement of subsequent restoration. For better appearance during the treatment, PGO is often performed with clear aligners, which have no metal brackets. It has been proven that the PGO with clear aligners can achieve generally satisfactory outcomes. However, its risk has not been fully known due to the paucity of relevant studies. CASE PRESENTATION: Three patients who needed esthetic rehabilitation with mild malocclusion were included in this study. After evaluation, a prosthetic solution alone was considered insufficient to provide optimal outcomes. Thus, they were treated using PGO with clear aligners (Invisalign Go, Align Technology, Santa Clara, California, USA) and accomplished prosthetic rehabilitation subsequently. Dental history and X-ray examination revealed that endodontically treated teeth (ETT) existed in all the cases. Intraoral photographs were collected to compare the pre-treatment and post-treatment dentition. After PGO, posterior ETT did not maintain their position as scheduled and lost occlusal contacts, while all the anterior teeth, including anterior ETT, were moved to the designed position. Corresponding prosthetic rehabilitation was used to solve it after consulting with the patients. CONCLUSIONS: Occlusal contact loss of posterior ETT is a potential risk in PGO with clear aligners, affecting the orthodontic result.

Effects of inorganic phosphate on stem cells isolated from human exfoliated deciduous teeth.

Calcium phosphate-based materials (CaP) are introduced as potential dental pulp capping materials for deciduous teeth. The present study investigated the influence of inorganic phosphate (Pi) on regulating stem cells isolated from human exfoliated deciduous teeth (SHED). SHEDs were treated with Pi. Cell cycle progression and apoptosis were examined using flow cytometry analysis. Osteo/odontogenic and adipogenic differentiation were analyzed using alizarin red S and oil red O staining, respectively. The mRNA expression profile was investigated using a high-throughput RNA sequencing technique. Pi increased the late apoptotic cell population while cell cycle progression was not altered. Pi upregulated osteo/odontoblastic gene expression and enhanced calcium deposition. Pi-induced mineralization was reversed by pretreatment of cells with Foscarnet, or p38 inhibitor. Pi treatment inhibited adipogenic differentiation as determined by decreased PPARγ expression and reduced intracellular lipid accumulation. Bioinformatic analysis of gene expression profiles demonstrated several involved pathways, including PI3K/AKT, MAPK, EGFR, and VEGF signaling. In conclusion, Pi enhanced osteo/odontogenic but inhibited adipogenic differentiation in SHED.

Healing of a Large Periapical Lesion Using Non-Surgical Root Canal Retreatment: A Case Report.

This case report highlights the successful healing of a large periapical lesion through non-surgical root canal retreatment. A 29-year-old male patient presented with a significant radiolucency associated with teeth #21 and #22, initially treated non-surgically. Despite the lesion's size, the treatment, which included thorough canal disinfection and obturation, led to substantial healing. A follow-up cone-beam computed tomography (CBCT) scan after one year confirmed the buccal cortical bone reformation and improvement in the incisive canal area except for the apical region of #21. Subsequently, root canal retreatment was performed for #21. Complete healing was achieved after two years, demonstrating that even extensive periapical lesions can be effectively treated with non-surgical endodontic retreatment, avoiding invasive surgical intervention.

Magnetic Resonance Images for the Prediction of Chronological Age Using Maxillary Third Molar Teeth: An Observational Study.

Introduction: Dental age estimation using third molars is a reliable method for estimating the age of individuals. Recently, magnetic resonance imaging (MRI) of the head and neck has been found to be applicable for age estimation of third molar teeth. In the present study, we aimed to apply the Modified Demirjian method of age estimation to magnetic resonance (MR) image sections for dental age estimation by determining the mineralization patterns of the maxillary third molars. Methods: MRI scans of the patients were performed using SIGNA™ 3.0Tesla MRI GE Healthcare (Chicago, USA) with a moving, multifunctional coil. Two expert radiologists with more than three years of experience independently analyzed the image sections using the open-source Digital Imaging and Communications in Medicine (DICOM) viewer software. The age and sex of the patients whose images were included in the study were recorded using a specially designed proforma. The stage of development of the maxillary third molars was determined using the modified Demirjian method. Inter observer agreement was calculated using the intra class correlation coefficient. Simple linear regression analysis was used to predict the actual age at the third molar development stage. Results: There was excellent agreement between observers (ICC =0.99 (95% CI = 0.98-0.99)). There was also a significant association between the maxillary third molar tooth development stage and chronological age of the individual (P=0.001; B=1.54; 95% CI = 0.71-2.37). Discussion: The findings from the present study establish that the Modified Demirjian method can also be reliably applied for dental age assessment in MR sections.

Effectiveness of pulpotomy in managing carious exposure in mature permanent teeth: A systematic review and meta-analysis.

OBJECTIVES: This quantitative systematic review evaluated whether pulpotomy performed with hydraulic calcium silicate cements may be used as an alternative to root canal treatment (RCT) in mature permanent teeth with carious pulp exposure. DATA SOURCES: A comprehensive search was conducted in PubMed, Web of Science, Scopus, and the Cochrane Library. No language restrictions were applied. The search included randomised controlled trials that compared pulpotomy to root canal treatment for managing carious exposure in mature permanent teeth. STUDY SELECTION: Studies were selected based on predetermined inclusion criteria: randomised controlled trials involving mature permanent teeth with carious pulp exposure, using hydraulic calcium silicate cements for pulpotomy. Non-comparative studies, case reports, and trials involving primary or immature permanent teeth were excluded. DATA: Data were extracted on success rates, clinical outcomes, follow-up periods, pain profiles, and potential complications. A meta-analysis was performed, revealing no statistically significant differences in success rates between pulpotomy and RCT. Both interventions demonstrated success rates exceeding 90 % at one-year and two-year follow-up periods. Pain profiles consistently showed lower post-operative pain intensity in the pulpotomy group compared to the RCT group during the first week. Potential complications, such as non-responsive pulp and difficulties in determining pulp vitality, were reported more frequently in the pulpotomy group. CONCLUSIONS: Pulpotomy with bioactive hydraulic calcium silicate cements shows comparable success rates to RCT in managing carious pulp exposure in mature permanent teeth. The results suggest pulpotomy as a viable, less invasive alternative to RCT, particularly in cases where preservation of pulp vitality is paramount. CLINICAL SIGNIFICANCE: This systematic review highlights pulpotomy as a less invasive and cost-effective alternative to root canal treatment in mature permanent teeth. With comparable success rates and lower post-operative pain, pulpotomy offers a promising approach to managing carious exposure and preserving tooth vitality.

A randomized controlled clinical trial of the performance of three bioactive endodontic cements in primary molar teeth diagnosed with reversible pulpitis: 1-year follow-up study.

OBJECTIVES: The objective of this clinical trial was to evaluate and compare the clinical and radiographic successes of three bioactive endodontic cements (BEC) including novel portland cement-based material releasing fluoride, resin-modified silicate glass cement, and pure tricalcium silicate-based cement-in the treatment of primary molars diagnosed with reversible pulpitis via indirect pulp capping. METHODS: Eighty-six (86) participants with previously untreated first and second primary molars were included in this study. The teeth were randomly allocated into three groups: pure tricalcium silicate-based cement, resin-modified silicate glass cement, and novel portland cement-based material releasing fluoride. Cavities were capped with the assigned cement after caries excavation using standard protocols. The teeth that underwent treatment were restored using glass ionomer cement and composite resin. Clinical and radiographic evaluations were performed at 1, 6, and 12 months. The data were analyzed using Pearson chi-square, Kruskal-Wallis H and Z test (P = 0.05). RESULTS: The success rate was 88 % (n = 25) in the pure tricalcium silicate-based cement group, 88.5 % (n = 26) in the resin-modified silicate glass cement group, and 100 % (n = 25) in the novel portland cement-based material releasing fluoride group. The differences at the 1st, 6th, and 12th month follow-up visits were not statistically significant among the groups (P > 0.05). No difference was found between the integrity of the resin composite restorations overlying pure tricalcium silicate-based cement, resin-modified silicate glass cement, and novel portland cement-based material releasing fluoride according to the USPHS criteria. CONCLUSIONS: Novel portland cement-based material releasing fluoride can be considered an alternative for preserving the tooth, as it showed a high success rate in treating primary molars diagnosed with reversible pulpitis via indirect pulp capping. CLINICAL SIGNIFICANCE: Novel Portland cement-based material releasing fluoride could be beneficial in the treatment of primary molars diagnosed with reversible pulpitis via indirect pulp capping.

A dual-labeled dataset and fusion model for automatic teeth segmentation, numbering, and state assessment on panoramic radiographs.

BACKGROUND: Recently, deep learning has been increasingly applied in the field of dentistry. The aim of this study is to develop a model for the automatic segmentation, numbering, and state assessment of teeth on panoramic radiographs. METHODS: We created a dual-labeled dataset on panoramic radiographs for training, incorporating both numbering and state labels. We then developed a fusion model that combines a YOLOv9-e instance segmentation model with an EfficientNetv2-l classification model. The instance segmentation model is used for tooth segmentation and numbering, whereas the classification model is used for state evaluation. The final prediction results integrate tooth position, numbering, and state information. The model's output includes result visualization and automatic report generation. RESULTS: Precision, Recall, mAP50 (mean Average Precision), and mAP50-95 for the tooth instance segmentation task are 0.989, 0.955, 0.975, and 0.840, respectively. Precision, Recall, Specificity, and F1 Score for the tooth classification task are 0.943, 0.933, 0.985, and 0.936, respectively. CONCLUSIONS: This fusion model is the first to integrate automatic dental segmentation, numbering, and state assessment. It provides highly accurate results, including detailed visualizations and automated report generation.

Clinical and Radiographic Evaluation of Mineral Trioxide Aggregate and Human Amniotic Membrane Pulpotomy in Primary Molars: A Randomized Clinical Trial.

Objectives: To clinically and radiographically compare the outcomes of pulpotomy with mineral trioxide aggregate (MTA) and human amniotic membrane (HAM) in primary molar teeth at 1, 3, 6, and 12 months. Materials and methods: The study was a randomized clinical trial with two arms. One arm consisted of participants whose pulpotomy was conducted using MTA, called group I, and the other arm, using HAM, was designated group II. Results: Both MTA and HAM exhibited 100% clinical success. Also, there were no signs of external resorption, periapical bone destruction, or internal resorption in both the MTA and the HAM groups at all four time intervals in this study. However, periodontal ligament widening was seen in 30% of the participants in the MTA group at 1-month and at the 12-month follow-up, whereas in the HAM group, periodontal ligament widening was found to reduce significantly from 22.2% at 1-month to 11.1% at the 12-month follow-up. Conclusion: The HAM exhibited favorable clinical and radiographic outcomes in the present study. Clinical significance: Mineral trioxide aggregate is the most preferred choice as a pulpotomy agent for deciduous teeth. However, various drawbacks associated with MTA have been fueling the need for newer, effective agents. HAM is not only easily available, cost-effective, and easy to handle but also favors tissue regeneration. The positive outcome of the present study strongly advocates the use of HAM as an alternative to MTA for pulpotomy in primary teeth. How to cite this article: Joseph EJ, Rao A, Mahabala KY, et al. Clinical and Radiographic Evaluation of Mineral Trioxide Aggregate and Human Amniotic Membrane Pulpotomy in Primary Molars: A Randomized Clinical Trial. Int J Clin Pediatr Dent 2024;17(6):641-646.

Restoration of a Peg Lateral Incisor Using the Putty Index Technique: A Case Report.

The restoration of peg lateral incisors poses considerable aesthetic and functional issues. This case report describes the use of a putty index approach for conservatively restoring peg-shaped maxillary lateral incisors with resin composites. A 21-year-old female patient with good periodontal health and appropriate occlusal interactions had treatment at the Department of Conservative Dentistry and Endodontics. The restoration method included initial impressions, shade selection, etching, bonding, and gradual composite application, followed by curing and polishing. The putty index was used as a reference to accurately recreate the palatal enamel. This approach provides a low-cost, minimally intrusive treatment that maintains natural tooth structure while producing satisfactory aesthetic outcomes. Direct adhesive resin restorations are being highlighted as a feasible option, as technology and bonding techniques progress. This case shows the significance of modifying treatment plans based on patient characteristics and practitioner expertise.

Periderm fate and independence of tooth formation are conserved across osteichthyans.

BACKGROUND: Previous studies have reported that periderm (the outer ectodermal layer) in zebrafish partially expands into the mouth and pharyngeal pouches, but does not reach the medial endoderm, where the pharyngeal teeth develop. Instead, periderm-like cells, arising independently from the outer periderm, cover prospective tooth-forming epithelia and are crucial for tooth germ initiation. Here we test the hypothesis that restricted expansion of periderm is a teleost-specific character possibly related to the derived way of early embryonic development. To this end, we performed lineage tracing of the periderm in a non-teleost actinopterygian species possessing pharyngeal teeth, the sterlet sturgeon (Acipenser ruthenus), and a sarcopterygian species lacking pharyngeal teeth, the axolotl (Ambystoma mexicanum). RESULTS: In sturgeon, a stratified ectoderm is firmly established at the end of gastrulation, with minimally a basal ectodermal layer and a surface layer that can be homologized to a periderm. Periderm expands to a limited extent into the mouth and remains restricted to the distal parts of the pouches. It does not reach the medial pharyngeal endoderm, where pharyngeal teeth are located. Thus, periderm in sturgeon covers prospective odontogenic epithelium in the jaw region (oral teeth) but not in the pharyngeal region. In axolotl, like in sturgeon, periderm expansion in the oropharynx is restricted to the distal parts of the opening pouches. Oral teeth in axolotl develop long before mouth opening and possible expansion of the periderm into the mouth cavity. CONCLUSIONS: Restricted periderm expansion into the oropharynx appears to be an ancestral feature for osteichthyans, as it is found in sturgeon, zebrafish and axolotl. Periderm behavior does not correlate with presence or absence of oral or pharyngeal teeth, whose induction may depend on 'ectodermalized' endoderm. It is proposed that periderm assists in lumenization of the pouches to create an open gill slit. Comparison of basal and advanced actinopterygians with sarcopterygians (axolotl) shows that different trajectories of embryonic development converge on similar dynamics of the periderm: a restricted expansion into the mouth and prospective gill slits.

Evaluation of the Bond Strength of Acrylic Teeth to Denture Base after Various Chemical Surface Treatments: An In Vitro Study.

AIM: The purpose of the present study was to assess the bonding capacity and efficacy of acrylic teeth to denture bases following two different chemical surface treatments. MATERIALS AND METHODS: A two-metal mold measuring 35 mm in length and 12 mm in diameter was created specifically for the investigation in order to standardize the wax pattern-based tooth attachment at 45°. Following standard protocol, 75 wax cylinder specimens were flasked, dewaxed, and surface treatment of teeth was done as follows with 25 samples in each group-group I: control group, group II: monomethyl methacrylate monomer group, group III: acetone group. The curing process was completed following the packing of the denture base material. The samples' shear bond strength was assessed using a universal testing machine. Every sample was taken out when it fractured, and the shear load (Newton, N) was noted. The significance of the variation in applied shear load was assessed using one-way analysis of variance (ANOVA) and post hoc ANOVA Tukey's honestly significant difference (HSD) test at the 5% level of significance. RESULTS: The maximum shear bond strength was found in the samples treated with acetone (183.21 ± 0.06) followed by samples treated with monomethyl methacrylate monomer (171.64 ± 0.12) and the control group (149.32 ± 0.04). A statistically significant difference was found between the different groups (p < 0.001). CONCLUSION: In conclusion, according to the current study's findings, acetone chemical surface treatment of acrylic teeth produced the strongest bond when compared with the control group and monomethyl methacrylate monomer. CLINICAL SIGNIFICANCE: In prosthodontic practice, artificial teeth regularly de-bond and separate from the denture base. A weak interface is produced when certain clinical conditions, such as ridge prominence, cause excessive cutting of the acrylic teeth and base. Where the denture base polymer meets the teeth's highly cross-linked matrix, it de-bonds adhesively. Therefore, the bonding between the acrylic teeth and the denture base material can be improved by the chemical surface treatment. How to cite this article: Chaudhuri NG, Lahiri B, Francis NT, et al. Evaluation of the Bond Strength of Acrylic Teeth to Denture Base after Various Chemical Surface Treatments: An In Vitro Study. J Contemp Dent Pract 2024;25(6):514-517.

Comparative Evaluation of Platelet-rich Fibrin and Treated Dentin Matrix in Regenerative Endodontic Treatment of Nonvital Immature Permanent Teeth: A Randomized Clinical Trial.

AIM: Clinical and radiographic evaluation of the efficacy of platelet-rich fibrin (PRF) and treated dentin matrix (TDM) in regenerative endodontic treatment and periapical healing of nonvital immature permanent teeth with chronic apical periodontitis. MATERIALS AND METHODS: Twenty-four children aged between 7 and 11 years, each presenting with a nonvital immature permanent upper central incisor, were selected. They were randomly allocated into two groups (n = 12), group I (PRF) and group II (TDM). Baseline clinical findings were recorded, and preoperative cone-beam computed tomography (CBCT) was taken. Follow-up was done clinically for 15 months at 3-month intervals (3, 6, 9, 12, and 15 months), and CBCT was taken at the end of the 15-month follow-up. Root length, apical diameter, radiographic root area (RRA), and size of the periapical lesion were quantitively assessed at the end of follow-up period and compared to the preoperative CBCT. RESULTS: Clinical success was 100% in both groups by the end of the follow-up period. Radiographically, after a 15-month follow-up, there was a significant increase in root length and RRA, and there was also a significant reduction in apical diameter and lesion size within each group (p < 0.05). However, there was no statistically significant difference between both groups regarding the mean percentage of increase in root length and mean percentage of reduction of apical diameter (p > 0.05). On the other hand, PRF showed more increase in RRA and more reduction in lesion size, with a statistically significant difference between both groups (p < 0.05). CONCLUSION: Both PRF and TDM were clinically successful. Platelet-rich fibrin showed better radiographic outcomes and periapical healing. CLINICAL SIGNIFICANCE: Platelet-rich fibrin is a viable scaffold to aid further root development and resolution of periapical lesions of nonvital immature permanent teeth. Further studies with different forms of TDM are needed to assess the efficacy of TDM in regenerative endodontic treatment of nonvital immature permanent teeth. How to cite this article: Asal MA, Elkalla IH, Awad SM, et al. Comparative Evaluation of Platelet-rich Fibrin and Treated Dentin Matrix in Regenerative Endodontic Treatment of Nonvital Immature Permanent Teeth: A Randomized Clinical Trial. J Contemp Dent Pract 2024;25(6):563-574.

Static Loading of Different Intraradicular Preparation Depths of Trinia Endocrowns in Maxillary Canines.

AIM: The aim of this study is to compare the fracture resistance of canine teeth restored using TRINIA Endocrowns with three different types of preparations (2, 3, and 4 intracanal preparations). MATERIALS AND METHODS: Thirty maxillary-extracted canines were collected. All teeth were fixed in orthodontic acrylic resin and decapitated at the level of the proximal cemento-enamel junction (CEJ). After being endodontically treated, specimens were distributed equally between 3 groups (n = 10) with different preparation depths (GT: 2 mm Intraradicular Preparation, GH: 3 mm Intraradicular Preparation, GF: 4 mm Intraradicular Preparation). Thirty TRINIA endocrowns were dry milled. After surface treatment, all endocrowns were bonded to their corresponding roots using Permaflo a dual-cure resin cement. Each specimen was then fixed in the lower part of a universal testing machine with a load cell of 5 KN, at an angle of 45 degrees to the tooth long-axis at 0.5 mm/min crosshead speed. Failure loads were recorded in Newton's. Data were recorded, organized, and statistically investigated. RESULTS: Shapiro-Wilk tests revealed that the data were not normally distributed. Descriptive statistics revealed a high mean fracture resistance of GH (647 N), then GT (475.6 N), and finally GF (353.9 N). The Kruskal-Wallis test revealed a significant difference that existed between the groups being studied (p = 0.036). CONCLUSION: TRINIA endocrowns with intracanal preparations of 2 and 3 mm provide more promising fracture resistance than those with intracanal preparations of 4 mm as a way of treating of root-canal-treated maxillary canines. TRINIA endocrowns (2 and 3 mm intracanal preparations) are as promising as fiber posts and all ceramic crowns in terms of fracture resistance. TRINIA endocrowns with 2 mm intracanal preparations are mostly reparable after failure, but those of 3 and 4 mm are mostly irreparable after failure. CLINICAL SIGNIFICANCE: Modifying endocrowns to have intraradicular projections, simulating Nayyar core, may improve the success and longevity of endocrowns in anterior teeth. How to cite this article: Alahmad AM, Alenezi AY, Rayyan M, et al. Static Loading of Different Intraradicular Preparation Depths of Trinia Endocrowns in Maxillary Canines. J Contemp Dent Pract 2024;25(6):575-580.

Effects of Stress on Biological Characteristics and Metabolism of Periodontal Ligament Stem Cells of Deciduous Teeth.

INTRODUCTION AND AIMS: Periodontal ligament stem cells (PDLSCs) from deciduous teeth (DePDLSCs) can perceive and respond to mechanical signals upon exposure to various environments. The effects of mechanical stress on the biological characteristics and metabolism of DePDLSCs were investigated using in vitro stress loading. METHODS: DePDLSCs were subjected to mechanical stresses of different strengths. Cell proliferation, expression of osteogenic/osteoclastic factors, apoptosis, and oxidative stress levels were evaluated using CCK-8 assays, alkaline phosphatase staining, real-time PCR, flow cytometry, and malondialdehyde and superoxide dismutase assays. Liquid chromatography-mass spectrometry was used to perform nontargeted metabolomic detection and analysis. RESULTS: Under stresses of 75 and 150 kPa, the expression of osteogenesis-related factors OPG, ALP, and RUNX2 decreased, and the ratio of RANKL/OPG significantly increased. A pressure of 150 kPa induced oxidative stress and caused a significant increase in cell apoptosis. Among the differential metabolites screened from the 150 kPa group, spermine, spermidine, ceramide, phosphatidylethanolamine, lysophosphatidylethanolamine, linoleic acid, and docosatrienoic acid were the most significantly upregulated. The metabolites screened from the 75 kPa group were mainly related to glycerophospholipid and sphingolipid metabolism, oxidative phosphorylation, and mineral absorption, which were common pathways affected in both experimental groups. CONCLUSION: A certain degree of mechanical stress can inhibit the proliferative activity and osteogenic differentiation of DePDLSCs, enhance their osteoclast-inducing ability, and cause elevated levels of cell apoptosis and oxidative stress. The metabolic expression profile of DePDLSCs changed significantly under stress. Understanding changes in cellular activity and metabolic reactions may provide an experimental basis for elucidating the role of mechanical stress in root resorption and periodontal tissue remodelling of deciduous teeth. CLINICAL RELEVANCE: Mechanical stress may affect periodontal tissue remodeling and root resorption of DePDLSc.

Research progress of piezoelectric materials in protecting oral health and treating oral diseases: a mini-review.

Piezoelectric materials, as a class of materials capable of generating electrical charges under mechanical vibration, have special piezoelectric effects and have been widely applied in various disease treatment fields. People generate vibrations in the oral cavity during daily activities such as brushing teeth, using electric toothbrushes, chewing, and speaking. These natural vibrations (or external ultrasound) provide ideal conditions for activating piezoelectric materials, leading to their high potential applications in protecting oral health and treating oral diseases. Based on this, this review reports on the research progress and trends of piezoelectric materials in the protection of oral health and the treatment of oral diseases in the past 5 years, and discusses its treatment mechanism, challenges and shortcomings, aiming to provide theoretical basis and new ideas for the future application of piezoelectric materials in the field of oral cavity. Finally, a brief outlook is provided, suggesting that the potential of piezoelectric materials may enable them to quickly move towards real clinical applications.

Stress Analysis of Periodontal Tissue in en Masse Retraction With Integration of Maxillary Anterior Teeth: A Three-Dimensional Finite Element Method Study.

OBJECTIVE: To simulate the en masse traction technique with the integration (EMTI) of six maxillary anterior teeth using a finite element model (FEM) and explore various protocols for maxillary protrusion. The study aimed to investigate root displacement and stress distribution in the periodontal ligament (PDL) by varying the retraction position and direction of EMTI applied to the maxillary anterior teeth. No actual participants were involved. MATERIALS AND METHODS: The FEM model included six teeth (central and lateral incisors and canines) with a PDL thickness of 0.3 mm. The model encompassing the alveolar bone (ALB) and EMTI had 180,528 elements and 47,836 nodes. The EMTI integrated six anterior teeth via a 0.9-mm-diameter stainless steel lingual wire, equipped with three moment arms extending toward the root apex: one midline (central arm) and two distal to the canines (lateral arms). The position and direction of the traction force applied to the three moment arms of the EMTI were varied to assess crown and apex displacement, as well as PDL stress. RESULTS: Lingual tipping was consistent across all protocols, emphasizing controlled incisor tipping. The application of horizontal traction at 10 mm and traction at 7 mm from the central and lateral arms of the EMTI, respectively, demonstrated the most uniform stress distribution across the PDL of all six anterior teeth. CONCLUSIONS AND CLINICAL SIGNIFICANCE: The FEM analysis results suggest that the new EMTI method, which retracts the maxillary anterior teeth as a unit, is effective for tooth movement and PDL stress distribution. The EMTI technique, with its specific traction protocols and emphasis on controlled tipping, appears to be a promising approach for addressing maxillary protrusions.