Ovrednotenje površinskih lastnosti ortodontskih nosilcev, žičnih lokov in njihovih degradacijskih procesov v ustni votlini

Mezeg, Uroš (author), Primožič, Jasmina (mentor)

Izhodišče. Površinske lastnosti nosilcev in žičnih lokov in njihove degradacijske spremembe v ustni votlini lahko vplivajo na silo trenja in s tem na učinkovitost ortodontske obravnave. Namen. Namen raziskave je bil ovrednotiti vpliv dolgotrajnega staranja ortodontskega materiala v ustni votlini, nabiranja oblog in vpliva lastnosti materiala žičnih lokov na silo trenja pri različnih kombinacijah nosilcev in žičnih lokov. Material in metode. V raziskavo smo vključili neuporabljene in uporabljene nosilce (brez zaklepa [NBZ1 in NBZ2] in z zaklepom [NZZ]) ter žične loke (nikelj-titanove [NiTi] in iz nerjavnega jekla [SS]), starane v ustni votlini 36 preiskovancev med ortodontskim zdravljenjem. Površinske lastnosti neuporabljenih in uporabljenih nosilcev in žičnih lokov smo analizirali z vrstičnim elektronskim mikroskopom (SEM) z energijsko disperzijsko spektroskopijo (EDS), njihovo morfologijo pa na mikroCT posnetkih. Kvantitativno analizo oblog smo izvedli na SEM posnetkih nosilcev, njihovo sestavo pa smo analizirali z uporabo EDS in infrardeče spektroskopije s Fourierjevo transformacijo. Triboelektrokemijske lastnosti neuporabljenih in uporabljenih NiTi in SS žičnih lokov smo ovrednotili z uporabo tribometra. Merjenje sile trenja smo opravili vzdolž utorov nosilcev spodnjih sekalcev različnih vrst v kombinaciji z NiTi ali SS žičnimi loki. Za statistično analizo smo uporabili neparametrične teste. Rezultati. Površinske lastnosti neuporabljenih in uporabljenih nosilcev in žičnih lokov so se značilno razlikovale, saj smo na uporabljenih ugotovili več oblog in degradacijskih sprememb, vendar te spremembe niso značilno vplivale na kemijske in mehanske lastnosti žičnih lokov. Ugotovili smo statistično značilno povezanost med vrsto nosilca in silo trenja (p<0,001). Ugotovili smo značilno višjo silo trenja pri uporabljenih NZZ kot pri neuporabljenih (p&#8804;0,001). Zaključki. Degradacijski procesi ortodontskega aparata v ustni votlini vplivajo na njegove površinske lastnosti, vendar se lahko učinkovitost njegovega delovanja v smislu zmanjšanja sile trenja pri premiku zoba bodisi poveča ali zmanjša, odvisno od zapletenega sinergističnega ali antagonističnega delovanja različnih dejavnikov. Na delovanje ortodontskega aparata najbolj vplivajo lastnosti nosilcev.

• Language: Slovenian
• Keywords: nosilec, žični lok, obloge, degradacija, sila trenja
• Work type: Doctoral dissertation
• Organization: MF - Faculty of Medicine
• Year: 2018
• PID: 20.500.12556/RUL-101527
• COBISS.SI-ID: 3924756
• Publication date in RUL: 14.06.2018

Secondary language

• Language: English
• Title: Evaluation of the surface characteristics of orthodontic brackets, archwires and their intraoral degradation processes

Abstract

Background. The surface properties of brackets and archwires and their possible intraoral degradation might affect the friction force and hence the effectiveness of orthodontic treatment. Aim. The aim was to assess the influence of long-term wear, debris accumulation and archwire material on friction force among different types of brackets and archwires couples. Material and Methods. As-received and used brackets (conventional [CB1 and CB2] and self-ligating [SLB]) and archwires (nickel-titanium [NiTi] and stainless steel [SS]), retrieved form 36 subjects undergoing orthodontic treatment, were included in the study. The surface characteristics of as-received and used brackets and archwires were analyzed by Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) and the morphology of brackets was assessed on microCT scans. Quantitative assessment of debris accumulation was performed on pictures of brackets obtained using SEM and its composition was analyzed by EDS and Fourier-Transform Infrared spectroscopy. The triboelectrochemical properties of as-received and used NiTi and SS archwires was evaluated using a tribometer. The friction testing was performed among four lower incisors’ brackets, of each type coupled with either NiTi or SS archwires. Non parametric tests were used for statistical analysis. Results. The surface characteristics of used brackets and archwires were significantly different and more debris and surface degeneration changes were seen on used material. However, this did not affect the triboelectrochemical properties of orthodontic archwires. Only bracket type was significantly correlated with the friction force (p<0.001). Significantly higher friction force (p&#8804;0.001) was seen in used SLB in comparison with as-received SLB. Conclusions. The intraoral degradation processes of orthodontic appliances affect their surface characteristics, however their effectiveness in terms of low friction tooth movement might be either improved or worsen depending upon a complex synergistic or antagonistic effect of different variables. In particular, performance of orthodontic appliances is mainly affected by brackets’ characteristics.

• Keywords: bracket, archwire, debris acumulation, degeneration, friction force