Diş Hekimliği Fakültesi / Faculty of Dentistry
Permanent URI for this collectionhttps://hdl.handle.net/11727/2120
Browse
321 results
Search Results
Item Pre-Chemoradiotherapy High Platelet Counts Predict Jaw Osteoradionecrosis In Locally Advanced Nasopharyngeal Carcinoma Patients(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-09-15) Somay, Efsun; Topkan, Erkan; Kucuk, Ahmet; Ozturk, Duriye; Ozkan, Emine Elif; Ozdemir, Beyza Sirin; Besen, Ali Ayberk; Mertsoylu, Huseyin; Pehlivan, Berrin; Selek, UgurIntroduction: This retrospective study aimed to investigate if pretreatment platelet (PLT) levels can predict the risk of osteoradionecrosis of the jaw (ORNJ) in patients with locally advanced nasopharyngeal carcinoma (LA-NPC) who received concurrent chemoradiotherapy (CCRT). Material &Methods: ORNJ instances were identified from LA-NPC patients' pre- and post-CCRT oral exam records. All pretreatment PLT values were acquired on the first day of CCRT. Receiver operating characteristic curve analysis was used to determine the optimal PLT cutoff that divides patients into two subgroups with distinctive ORNJ rates. The primary outcome measure was the association between pretreatment PLT values and ORNJ incidence rates. Results: The incidence of ORNJ was 8.8 % among the 240 LA-NPC patients analyzed. The ideal pre-CCRT PLT cutoff which divided the patients into two significantly different ORNJ rate groups was 285,000 cells/mu L (PLT <= 285,000 cells/mu L (N = 175) vs. PLT > 285,000 cells/mu L (N = 65)). A comparison of the two PLT groups revealed that the incidence of ORNJ was substantially higher in patients with PLT > 285,000 cells/L, than in those with PLT <= 285,000 cells/L, (26.2% vs. 2.3 %; P < 0.001). The presence of pre-CCRT >= 3 tooth extractions, any post-CCRT tooth extractions, mean mandibular dose >= 34.1 Gy, mandibular V57.5 Gy >= 34.7 %, and postCCRT tooth extractions > 9 months after CCRT completion were also associated with significantly increased ORNJ rates. A multivariate Cox regression analysis demonstrated that each characteristic had an independent significance on ORNJ rates after CCRT. Conclusion: An affordable and easily accessible novel biomarker, PLT> 285,000 cells/L, may predict substantially higher ORNJ rates after definitive CCRT in individuals with LA-NPC. (c) 2024 Elsevier Masson SAS. All rights reserved.Item Comment on "Management of 80 Sinonasal Undifferentiated Carcinomas. Retrospective Multicentre Study of the French Network of Rare Head and Neck Cancers (REFCOR).(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-06-21) Topkan, Erkan; Somay, Efsun; Selek, UgurItem Evaluation Of Different Machine Learning Algorithms For Extraction Decision In Orthodontic Treatment(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-05-31) Kokturk, Begum; Pamukcu, Hande; Gozuacik, OmerIntroductionThe extraction decision significantly affects the treatment process and outcome. Therefore, it is crucial to make this decision with a more objective and standardized method. The objectives of this study were (1) to identify the best-performing model among seven machine learning (ML) models, which will standardize the extraction decision and serve as a guide for inexperienced clinicians, and (2) to determine the important variables for the extraction decision.MethodsThis study included 1000 patients who received orthodontic treatment with or without extraction (500 extraction and 500 non-extraction). The success criteria of the study were the decisions made by the four experienced orthodontists. Seven ML models were trained using 36 variables; including demographic information, cephalometric and model measurements. First, the extraction decision was performed, and then the extraction type was identified. Accuracy and area under the curve (AUC) of the receiver operating characteristics (ROC) curve were used to measure the success of ML models.ResultsThe Stacking Classifier model, which consists of Gradient Boosted Trees, Support Vector Machine, and Random Forest models, showed the highest performance in extraction decision with 91.2% AUC. The most important features determining extraction decision were maxillary and mandibular arch length discrepancy, Wits Appraisal, and ANS-Me length. Likewise, the Stacking Classifier showed the highest performance with 76.3% accuracy in extraction type decisions. The most important variables for the extraction type decision were mandibular arch length discrepancy, Class I molar relationship, cephalometric overbite, Wits Appraisal, and L1-NB distance.ConclusionThe Stacking Classifier model exhibited the best performance for the extraction decision. While ML models showed a high performance in extraction decision, they could not able to achieve the same level of performance in extraction type decision.Item Letter to the Editor: Local Treatment of Children Suffering From Parameningeal Rhabdomyosarcoma - A Retrospective Single-Center Study From China(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-05-19) Topkan, Erkan; Somay, Efsun; Selek, Ugur; Pehlivan, BerrinItem Comment on 'Accelerated Hypofractionated Chemoradiation For Locally Advanced Head And Neck Cancer During Covid-19 Pandemic: A Tertiary Care Experience'(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-10-30) Somay, Efsun; Topkan, Erkan; Selek, Ugur; Pehlivan, BerrinItem Letter to the Editor: Authors' Response(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-05-14) Cetin, Mehtap Bilgin; Sezgin, Yasemin; Yilmaz, Mediha Nur Nisanci; Secgin, Cansu KoseogluItem Comment on Poor Dental Health as a Risk Factor for Alveolar Ridge Malignancies(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-03-21) Somay, Efsun; Topkan, ErkanItem Is The Repair Bond Strength Affected When Substrate And Repair Composite Are Not Of The Same Kind? A Systematic Review And Meta-Analysis: Effect Of Repair Composite On Repair Bond Strength(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-03-21) Kose, Leyla Kerimova; Isik, Hatice; Eyuboglu, Tan Firat; Ozcan, Mutlu; Cehreli, Sevi Burcak; Arhun, NeslihanThe aim was to evaluate the influence of repair resin type on repair bond strength in the direct resin restorations through a systematic review. Electronic databases MEDLINE via PubMed, Web of Science, Scopus, BBO, and LILACS were searched, and the reference lists of relevant studies were further hand-searched. A total of 15,709 articles that were browsed yielding to a final of five studies were included in meta-analysis. Analyses were performed using R software with the 'metafor' package, with standardized mean differences employed. A multi-level meta-analysis was conducted utilizing restricted maximum-likelihood estimates (p <= .05). In the shear bond strength group, significant heterogeneity was observed (Q = 50.274, p < .0001), whereas no significant heterogeneity was detected in the microtensile bond strength group (Q = 5.102, p = .4063). Separate analyses of both shear bond strength and microtensile bond strength groups showed no statistically significant differences between dissimilar and similar materials (p > .05). Egger's regression indicated no evidence of publication bias in either group. Sensitivity analyses revealed statistically insignificant pooled effect sizes for shear bond strength. In the microtensile group, one study influenced the results when excluded from the analysis. It could be suggested that the repair of composite resin with the same kind of resin composite is not mandatory.Item Comment on Poor Dental Health as a Risk Factor for Alveolar Ridge Malignancies(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-03-21) Somay, Efsun; Topkan, ErkanItem Comment on Poor Dental Health as a Risk Factor for Alveolar Ridge Malignancies(Başkent Üniversitesi Diş Hekimliği Fakültesi, 2024-03-21) Somay, Efsun; Topkan, Erkan