1. Three-dimensional ultrasound evaluation of tongue posture and its impact on articulation disorders in preschool children with anterior open biteSanda Lah Kravanja, Irena Hočevar-Boltežar, Maja Marolt-Mušič, Ana Jarc, Ivan Verdenik, Maja Ovsenik, 2018, original scientific article Abstract: Background. Tongue posture plays an important role in the etiology of anterior open bite (AOB) and articulation disorders, and is crucial for AOB treatment planning and posttreatment stability. Clinical assessment of tongue posture in children is unreliable due to anatomical limitations. The aim of the study was to present functional diagnostics using three-dimensional ultrasound (3DUS) assessment of resting tongue posture in comparison to clinical assessment, and the associations between the improper tongue posture, otorhinolaryngological characteristics, and articulation disorders in preschool children with AOB. Patients and methods. A cross-sectional study included 446 children, aged 3-7 years, 236 boys and 210 girls, ex- amined by an orthodontist to detect the prevalence of AOB. The AOB was present in 32 children. The control group consisted of 43 children randomly selected from the participants with normocclusion. An orthodontist, an ear, nose and throat (ENT) specialist and a speech therapist assessed orofacial and ENT conditions, oral habits, and articulation disorders in the AOB group and control group. Tongue posture was also assessed by an experienced radiologist, us- ing 3DUS. The 3DUS assessment of tongue posture was compared to the clinical assessment of orthodontist and ENT specialist. Results. The prevalence of AOB was 7.2%. The AOB group and the control group significantly differed regarding improper tongue posture (p < 0.001), and articulation disorders (p < 0.001). In children without articulation disorders from both groups, the improper tongue posture occured less frequently than in children with articulation disorders (p < 0.001). After age adjustment, a statistical regression model showed that the children with the improper tongue posture had higher odds ratios for the presence of AOB (OR 14.63; p < 0.001) than the others. When articulation disor- ders were included in the model, these odds ratios for the AOB became insignificant (p = 0.177). There was a strong association between the improper tongue posture and articulation disorders (p = 0.002). The 3DUS detected the high- est number of children with improper resting tongue posture, though there was no significant difference between the 3DUS and clinical assessments done by orthodontist and ENT specialist. Conclusions. The 3DUS has proved to be an objective, non-invasive, radiation free method for the assessment of tongue posture and could become an important tool in functional diagnostics and early rehabilitation in preschool children with speech irregularities and irregular tongue posture and malocclusion in order to enable optimal condi- tions for articulation development.
Keywords: anterior open bite, tongue posture, three-dimensional ultrasound
Published in DiRROS: 02.07.2024; Views: 102; Downloads: 50
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2. Tribocorrosive study of new and in vivo exposed nickel titanium and stainless steel orthodontic archwiresTadeja Kosec, Petra Močnik, Uroš Mezeg, Andraž Legat, Maja Ovsenik, Monika Jenko, John T. Grant, Jasmina Primožič, 2020, original scientific article Abstract: The surface, corrosion and wear properties of new and in vivo exposed nickel titanium (NiTi) and stainless steel (SS) archwires used in orthodontic treatment were investigated. Electrochemical and tribo-electrochemical tests in artificial saliva were performed in order to define corrosion properties and to estimate wear rate of new and in vivo exposed NiTi and SS archwires. The surface chemical analysis of the passive film on the NiTi and SS archwires before and after tribocorrosion tests was performed by Auger Electron Spectroscopy (AES). In vivo exposed NiTi and SS archwires had better electrochemical properties than new archwires due to the protective nature of oral deposits. Total wear and coefficients of friction were higher among in vivo exposed archwires and higher in NiTi archwires in comparison to SS archwires. The estimated thickness of the TiO2 passive film on as-received NiTi is 8 nm, while the passive Cr2O3 film on as-received SS is just 1–2 nm. On in vivo exposed NiTi archwire, a 60–80 nm thick organic film/dental plaque was observed, and on SS, it was thinner, at about 60 nm. This research shows the importance of combining AES with electrochemical testing, to characterize tribocorrosive properties of NiTi and SS orthodontic archwires.
Keywords: archwires, NiTi, stainless steel, wear
Published in DiRROS: 24.08.2023; Views: 398; Downloads: 155
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3. Estimation of the corrosion properties for titanium dental alloys produced by SLMTadeja Kosec, Mirjam Bajt Leban, Maja Ovsenik, Matej Kurnik, Igor Kopač, 2022, original scientific article Abstract: Titanium alloys are known for their excellent biocompatible properties. The development of additive-manufacturing technologies has increased the interest in the use of Ti-6Al-4V, produced by selective laser melting (SLM) method, also in dentistry, i.e., prosthodontics and orthodontics. In the present paper, the effect of laser printing parameters in the selective laser melting (SLM) process on the porosity and corrosion behavior of Ti-6Al-4V dental alloy was metallographically and electrochemically studied. All the tests were performed in artificial saliva at 37 °C. Different forms of Ti-6Al-4V alloy were selected: a reference sample, i.e., pre-fabricated milling disc in wrought condition and four different 3D-printed samples made from Ti-6Al-4V powder using the SLM method, one being heat treated. Electrochemical, spectroscopic and hardness measurements were employed in the study. It was shown that the SLM-produced Ti-6Al-4V samples with different printing parameters have similar microstructural and electrochemical properties, while the electrochemical properties of a reference and thermally treated 3D-printed sample were different, most probably due to the change in the microstructure of the alloys. The corrosion properties were related to the microstructural properties as well as to the pore density.
Keywords: Ti-6Al-4V, dental alloys, artificial saliva, selective laser melting, corrosion
Published in DiRROS: 31.05.2023; Views: 400; Downloads: 183
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