Vol. 15 No. 2 (2025): International Dental Research

Aim: The aim of this in vitro study was to compare the marginal fit and fracture strength of endocrown restorations applied to maxillary canines, using different manufacturing methods. Methodology: An extracted upper canine tooth was prepared for endocrown placement. Three methods were used to create the endocrowns: Fused Deposition Modeling (FDM) 3D printing with Essentium Polyetheretherketone (PEEK) filament, CAD/CAM milling with Juvara PEEK disk, and SLS 3D printing with Cr-Co metal (N=10). Additionally, 30 identical canine tooth replicas were produced using an Asiga 3D printer with a model resin, and the crown restorations were cemented with a resin luting cement. Fracture strengths were tested, and marginal fits were evaluated using Geomagic Control X software. Statistical analysis was performed, and Weibull analysis was used to assess fracture strength values. Results: The laser-sintered endocrowns exhibited higher fracture strength (1351 N) compared to PEEK FDM (735.341 N) and milled PEEK (826.733 N) endocrowns. The highest Weibull modulus was found for milled PEEK (3.978), while the lowest was for the Cr-Co laser-sintered material (2.912). A significant difference in marginal fit was observed on the palatal surface of the PEEK FDM group compared to the other two groups (p=0.048). However, no significant differences were found on the mesial, distal, or buccal surfaces. Conclusion: The findings indicate that PEEK endocrowns produced by FDM and milling offer clinically acceptable fracture strength and marginal fit, with PEEK being closer to the dentin elastic modulus. The significantly higher Weibull modulus of PEEK endocrowns produced by the FDM Printer and milling enables us to make more accurate intraoral fracture predictions.

Aim: In the field of dentistry, panoramic radiography (PR) and dental volumetric tomography (DVT) play a crucial role in assessing the position of impacted teeth and their relationship with neighboring anatomical structures. The objective of this study was to investigate the association between impacted mandibular teeth and adjacent dental structures, as well as the surrounding anatomical formations, using both PR and DVT imaging techniques. Methodology: In this retrospective study, we examined DVT and PR images of a total of 150 patients who sought treatment at Dicle University Faculty of Dentistry between 2015 and 2021. The main objective was to assess the prevalence of impacted teeth, specifically in the mandible region, and to analyze their location, as well as their association with neighboring teeth and surrounding anatomical structures, utilizing both PR and DVT imaging modalities. The collected data were analyzed using the licensed IBM SPSS 21 software package. Results: The study included a total of 150 patients, comprising 70 women and 80 men, in whom 206 impacted teeth were detected in the radiographs. Among these, the most common classifications were impacted lower-third molars (ILTM), with a vertical orientation accounting for 41.04%, class B with a rate of 50.87%, and class II with 68.79% prevalence. The inferior alveolar canal (IAC) was found to be positioned inferiorly in 71.68% of cases, with no bone septum observed between the IAC and ILTM root in 50.87% of cases. In 23.7% of cases, the ILTM root was in contact with the lingual cortical bone, while lingual bone perforation was observed in 8.67% of cases. Significant statistical differences were found between the DVT and PR images concerning the position of the IAC and its relationship with the lingual bone, as well as the examination of distal caries and external root resorption (ERR) in the second molar tooth (p<0.05). Additionally, impacted canines were predominantly observed in the buccal position, six out of 14 teeth being in contact with the incisive canal. Positioned lingually, impacted premolars and supernumerary premolars were frequently observed. Second molars were commonly seen to be mesially inclined and not in contact with the IAC. Conclusion: The alignment and positioning of teeth within the mandible are intricately linked to the nearby anatomical structures. It is crucial to regularly monitor impacted teeth using PR, and, in cases where there is a higher risk, it is recommended to augment the diagnosis with three-dimensional DVTs.

Aim: This study evaluated the effects of activator-type functional appliance therapy on the articular disc of the temporomandibular joint (TMJ) following forward movement of the mandible in individuals with skeletal Class II malocclusion via magnetic resonance imaging (MRI). Specifically, this study compared individuals with normal growth and development to those who had undergone treatment. Methodology: This study was conducted using a controlled, randomized, crossover design. The study group consisted of 40 individuals with skeletal Class II malocclusion, whereas the control group included 20 individuals with the same anomalies who did not receive treatment. The treatment group underwent therapy with an activator-type functional appliance for a period of six months, during which MRI scans were obtained from participants. The soft- and hard tissue characteristics of the TMJ were assessed using MRI. Data were analyzed using SPSS software, with a statistical significance level of p<0.05. Results: In the treatment group, significant changes were observed in the anterior position of the mandibular condyle and TMJ disc angles. With respect to disc position and configuration, an increase in the biconcave structure and in the anterior angle, and a decrease in the posterior angle, were noted in the treatment group. These changes were not statistically significant in the control group. Additionally, improvement in the TMJ disc position was detected in individuals in the treatment group. Conclusion: Activator-type functional appliance therapy can have positive effects on the mandibular condyle and TMJ disc position in individuals with Class II malocclusion. MRI has been highlighted as an effective method for evaluating soft and hard tissues of the TMJ. This treatment approach supports orthodontic outcomes by promoting TMJ adaptation.

Aim: The purpose of this study was to compare the fracture strengths of post systems used with CAD/CAM and traditional methods. Methodology: A total of 30 maxillary central teeth were used in the study. After the root lengths were standardized to be 10 mm, post sockets were prepared in the root canals. A total of 30 teeth were randomly divided into three groups (n=10). The post sockets were measured with silicone and sent to the laboratory. Samples were prepared after laboratory procedures. PEEK posts, fiber posts, and zirconia posts were cemented to the post sockets with resin cement. The test samples were kept at room temperature for 24 hours and then subjected to thermal cycling. After thermal cycling, force was applied to the test samples at a speed of 1 mm/min until the sample fractured. Statistical analysis was performed using one-way ANOVA (p<0.05) in SPSS. Results: The statistical analysis revealed a significant difference in mean fracture resistance among the groups (p<0.05). The highest mean fracture strength value in the tested groups was observed in the fiber post group (410.9 ± 106.2 N). The lowest mean was observed in the PEEK post group (215.1 ± 77.7). Conclusion: All groups of PEEK, glass fiber, and zirconium oxide post-cores showed sufficient fracture strength when compared with the mean of the maximum forces that can be applied to the teeth in the anterior region.

The purpose of this study is to discuss the applications of PEEK in pediatric dentistry and the advantages of PEEK material in terms of periodontal health. In pediatric dentistry, there is a continuous search for biocompatible, esthetic, and durable materials to overcome the limitations of conventional options such as stainless steel and zirconia. Polyetheretherketone (PEEK), a high-performance semicrystalline polymer, has emerged as a novel alternative due to its superior mechanical properties, resistance to heat and chemicals, and an elastic modulus comparable to human bone. This review aims to evaluate the material characteristics of PEEK, its impact on periodontal health, and its clinical applications within pediatric dentistry. PEEK is amenable to digitalization and can be fabricated using CAD/CAM milling and 3D printing, ensuring precise fit and patient comfort. In pediatric orthodontics and space maintenance, PEEK serves as an esthetic, metal-free alternative, eliminating risks of nickel allergy while providing high strength and significantly reduced weight compared to traditional appliances. For restorative procedures, PEEK is utilized in crowns, endocrowns, and post-core systems. Its shock-absorbing capability allows for favorable stress distribution in dentin, reducing the risk of root fractures often associated with rigid materials like metal or glass fibers. Additionally, its low specific gravity and biocompatibility make it an effective material for obturators in treating cleft lip and palate defects. Regarding periodontal health, polished PEEK surfaces demonstrate low plaque affinity and acceptable surface roughness, supporting gingival health. PEEK offers distinct advantages in pediatric dentistry, particularly for patients requiring metal-free, lightweight, and shock-absorbing restorations. While it presents a promising alternative to traditional materials, achieving durable adhesion requires specific surface treatments, and further prospective clinical studies are warranted to validate its long-term performance.

In contemporary endodontics, the core objective is to thoroughly cleanse and disinfect the root canal system. While shaping the canals is an important step, it alone is not sufficient. Successful treatment relies on a combined chemo-mechanical approach, which ensures the removal of organic tissue remnants, microbial contaminants, and their by-products from within the canal space. In this context, flushing the root canals with appropriate irrigation solutions is of great importance. The irrigation solutions used play a critical role in dissolving both organic and inorganic tissues and reducing the microbial load. However, the effect of irrigation can be further enhanced by actively circulating and agitating the solution within the canals. For this reason, activation methods such as ultrasonic or sonic activation systems, negative pressure irrigation techniques, and laser-assisted methods have become widely used in treatment protocols in recent years. In short, successful endodontic treatment is not only achieved by shaping the canal; it is also possible through the correct selection of irrigation solutions, sufficient duration of use, and effective activation. Once these procedures are properly carried out, the root canal system becomes more effectively disinfected, which in turn enhances the likelihood of achieving a successful long-term treatment outcome. This article comprehensively evaluates the activation devices used in today's endodontic practices and the new systems recently introduced to the market in terms of their advantages and limitations. Furthermore, current activation techniques are discussed comparatively, and their contributions to clinical practice and differences in use are debated.

Laser technology has gained increasing attention in endodontics due to its potential to enhance disinfection, improve treatment outcomes, and support minimally invasive clinical approaches. The aim of this review was to provide a comprehensive overview of commonly used laser systems in endodontics and to summarize their current clinical applications. Various laser types, including carbon dioxide (CO₂), diode, neodymium-doped yttrium aluminum garnet (Nd:YAG), neodymium-doped yttrium aluminum perovskite (Nd:YAP), erbium-doped yttrium aluminum garnet (Er:YAG), and erbium chromium-doped yttrium scandium gallium garnet (Er,Cr:YSGG), have been evaluated in terms of their mechanisms of action and clinical effectiveness. Lasers are used in multiple endodontic procedures, such as root canal disinfection, smear layer removal, pulp capping, pulpotomy, dentin hypersensitivity management, and treatment of pulp and periapical pathologies. In particular, laser-activated irrigation techniques, including photon-induced photoacoustic streaming (PIPS) and shock wave–enhanced emission photoacoustic streaming (SWEEPS), have shown promising results in improving irrigation efficacy and bacterial elimination, especially in complex root canal anatomies. Compared with conventional irrigation methods, these advanced laser techniques enhance the penetration of irrigants into dentinal tubules while minimizing thermal damage to surrounding tissues. Erbium lasers, owing to their high water absorption and photoacoustic effects, appear to be especially effective for smear layer removal and biofilm disruption. Other laser systems, such as diode and Nd:YAG lasers, also contribute to antimicrobial activity and postoperative pain reduction when used appropriately. However, laser parameters, irradiation time, and safety considerations remain critical for successful clinical outcomes. In conclusion, laser systems offer significant advantages in endodontic therapy by improving disinfection, supporting tissue preservation, and enabling minimally invasive techniques. Further well-designed clinical studies are needed to strengthen the evidence regarding their long-term efficacy, safety, and optimal clinical protocols.