Altındağ, Ali; Akyüz, Mehmet; Uzun, Sultan; Yüksel, İbrahim Burak; Mağat, Güldane

Background: The aim of this study was to investigate the relationship between the positions of impacted mandibular third molars and the gonial angle and ramus height, as measured on panoramic radiographs, according to the Pell and Gregory/Winter classifications. Methods: This retrospective study included panoramic radiographs of 700 patients (350 males and 350 females) aged 18–62 years, who presented with bilaterally impacted mandibular third molars. The gonial angle and ramus height were measured, and the position of the impacted third molars was categorized based on the Pell and Gregory/Winter classification systems. Results: The most common third molar impaction position observed was vertical, followed by mesioangular and horizontal positions. The study found that a high gonial angle was more frequently observed in males, while a low gonial angle was more common in females. No significant association was identified between the type of mandibular third molar impaction and the gonial angle or ramus height. Additionally, individuals with high gonial angles had lower ramus heights. Individuals with impacted teeth in the “other” position had statistically higher gonial angles (p < 0.05). Conclusion: The study concludes that there is no significant correlation between the gonial angle, ramus height, and the type of mandibular third molar impaction. However, individuals with impacted teeth in the “other” position were found to have higher gonial angles, which may increase the risk of mandibular fractures. These findings show that although certain impaction types are more prevalent, mandibular anatomical parameters such as gonial angle and ramus height do not appear to significantly influence impaction patterns when assessed on panoramic radiographs.

Haşimoğlu, Elif; Balaban, Emre; Halat, İsmail Burak; Akın, Muhammet

Background: Bruxism-related clenching can impose excessive mechanical loads on the temporomandibular joint (TMJ), particularly in the presence of anterior disc displacement (ADD). Understanding how different therapeutic strategies influence joint stress under these conditions can support exploratory, hypothesis-generating assessment of biomechanical unloading within patient-specific models. Therefore, this study aimed to evaluate TMJ stress distributions under normal and displaced disc conditions and to assess the biomechanical effects of simulated treatment strategies using a patient-specific finite element framework. Materials and methods: A patient-specific three-dimensional finite element model derived from clinically acquired computed tomography (CT) data was constructed to simulate TMJ biomechanics during clenching. Stress patterns were analyzed under three disc conditions: normal disc position, unilateral ADD, and bilateral ADD. Intervention scenarios included simulated reductions in masticatory muscle forces representing botulinum toxin Type-A (BoNT-A) therapy and occlusal splint therapy, applied individually and in combination. Peak von Mises stresses within the articular disc and joint structures were compared across all conditions. Results: ADD increased peak stresses within the articular disc and adjacent joint surfaces and shifted stress concentration toward the posterior region of the disc. Simulated reductions in muscle force resulted in progressive decreases in peak joint stresses as additional muscle groups were targeted, whereas splint therapy alone provided moderate stress reduction. The greatest biomechanical unloading was observed when occlusal splint therapy was combined with BoNT-A–related muscle force reduction. Notably, a strategy targeting the masseter and temporalis muscles combined with splint therapy produced lower peak disc stresses than a three-muscle reduction strategy without splint across all disc conditions. Conclusion: In this exploratory single-patient finite element model, ADD increased predicted TMJ stresses during clenching, whereas simulated muscle-force reduction and splint-related changes in occlusal load transmission reduced peak stress metrics, with the largest reductions observed in combined scenarios. These results are hypothesis-generating and intended for relative, within-model comparisons under stated assumptions rather than clinical treatment recommendations.

Gömleksiz, Seda; Gömleksiz, Oğuzhan

Background: The study aimed to investigate the effect of different cavity depths on the degree of conversion (DC) and surface microhardness (MH) of low-shrinkage resin composites. Methods: Three low-shrinkage resin composites (Clearfil Majestry Posterior/CMP, Beautifil II LS/BL, Charisma Diamond/CD) and one conventional nanohybrid resin composite (Filtek Z550/FZ) as control were evaluated. For each composite material, a total of 12 disc-shaped samples were prepared using plastic molds with two different depths (2 mm and 4 mm) (n = 6). The same sample preparation protocol was applied for the DC and MH tests, and a total of 96 samples were prepared, 48 for each test. Resin composites filled into molds with the incremental technique were cured with LED light unit only from the top surface. DC was determined by Fourier transform infrared (FTIR) spectroscopy; MH was determined using the Vickers hardness tester. Data were statistically analyzed using Robust and two-way variance analyses (p < 0.05). Results: For all resin composites, there was no significantly difference in DC and MH between the 2 mm and 4 mm cavity depths. BL showed the highest DC values at both cavity depths, while CD showed the lowest (p < 0.001). At both cavity depths, the highest MH values on bottom-top surfaces ​​were obtained in CMP, while the lowest ​​were in BL. The top surface MH values ​​were higher in all resin composites than the bottom surfaces. Conclusions: Increasing cavity depth may not negatively affect the DC and MH of low-shrinkage resin composites. Moreover, resin composite material formulations may have a higher potential effect on these parameters. Clinical trial number: Not applicable.

Okumuş, Ömer F.; Kurt, Nezahat; Kantarcı, Alpdoğan

Background: Mitofusin (Mfn) is a mitochondrial fusion protein. It has two isoforms (Mfn1 and 2) and is critical in intracellular energy production, calcium transfer, and phospholipid metabolism. Based on previous evidence linking mitochondrial function with the pathophysiology of periodontal inflammation, we hypothesized that salivary Mfn1 and Mfn2 levels may differ across periodontal health, gingivitis, and periodontitis, and that these levels correlate with markers of inflammatory and oxidative stress. Although previous studies have suggested that Mfn2 plays a role in inflammatory and oxidative pathways, clinical evidence regarding its role in periodontal disease is lacking. The null hypothesis of this study was that salivary Mfn levels are not significantly altered with periodontal conditions and are not correlated with inflammation or oxidative stress markers in saliva. Methods: A total of 81 participants were included in this cross-sectional case-control study, with 27 individuals per group. Periodontally healthy patients, patients with gingivitis, and patients with stage 3 or stage 4 grade C periodontitis were recruited for the study. Mfn-1 and Mfn-2 levels were measured. To identify their correlation with inflammatory mechanisms, interleukin-1β levels, total oxidative status (TOS), and total antioxidant status (TAS) were determined using enzyme-linked immunosorbent assay and colorimetric measurements. The oxidative stress index (OSİ) was calculated. Results: Salivary Mfn1 levels were significantly higher in patients with periodontitis compared to healthy controls (36.54 ± 13.15 ng/mL, 24.67 ± 8.69 ng/mL, p < 0.001). No significant difference was observed between the groups in terms of Mfn2 levels (p > 0.05). While significant differences were found between Group P and Group H in TAS and OSI values (p < 0.05), TOS values ​​did not show any significant difference between the groups (p > 0.05). A positive correlation was found between Mfn1 and Mfn2 and IL-1β levels (p < 0.05). Mfn1 and Mfn2 did not have any significant correlation with TAS, TOS, or OSI values (p > 0.05). Conclusions: Elevated Mfn1 levels in the saliva of patients with periodontitis suggested that mitochondrial function was disrupted in severe periodontitis. Mitofusin levels showed no significant correlation with oxidative stress markers in this study. Trial registration: This study was registered in ClinicalTrials.gov under the number NCT06510608 on July 18, 2024.

Gömleksiz, Seda; Okumuş, Ömer Faruk

Background: This study aimed to investigate the effect of whitening toothpastes on the color stability and surface roughness of resin composites stained with coffee and cigarette smoke. Methods: Seventy-two disk-shaped specimens (6 × 2 mm) of suprananohybrid resin composite were randomly divided into two groups and exposed to coffee and cigarette smoke (n = 36). After staining, the samples randomly divided into four groups according to whitening toothpastes and were brushed for 4 min: Opalescence Whitening (OW); Colgate Optic White (COW); Curaprox Black is White (CPX) and, distilled water (control) (n = 9). Color was measured with spectrophotometer at the initial, after staining, and after brushing, and surface roughness was measured with profilometer at the initial and after brushing. A surface morphology analysis was examined using scanning electron microscopy and atomic force microscopy. The obtained data were statistically analyzed. (p < 0.05). Results: Cigarette smoke caused a significantly higher color change than coffee in the resin composite (p < 0.05). Brushing with hydrogen peroxide and silica-containing whitening toothpaste showed significant differences in color change (p < 0.05). The lowest whitening effect was found in activated charcoal-containing toothpaste. While all toothpastes increased the degree of surface roughness of resin composites, the highest roughness was caused by whitening toothpastes containing activated charcoal. (p < 0.05). Conclusions: The color stability and surface properties of resin composites can be affected by brushing them with whitening toothpaste. The utilization of whitening toothpaste containing hydrogen peroxide can be considered a safe method for increasing the whiteness of discolored resin composites.