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1

Analysis of shrinkage stresses arising during polymerization of orthodontic adhesive systems

Malkiewicz Konrad, Krasowski Michał, Bartczak Jakub, Radziejewska Marta, Bociong Kinga

Polimery

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2023

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Vol. 68, nr 5

269--275

EN

The aim of the study was to evaluate the shrinkage stress during cross-linking of composite orthodontic adhesive systems. The elastic-optical method was used for shrinkage stress analysis. Based on the obtained results, basic statistics were determined, including averages and standard deviations. For the comparative analysis of the mean values, the Tukey HSD test was used at the significance level α = 0.05. The average value of shrinkage stress during cross-linking ranged from 7.2 to 11.5 MPa.

PL

Celem pracy była ocena naprężeń skurczowych podczas sieciowania kompozytowych ortodontycznych systemów adhezyjnych. Do analizy naprężeń skurczowych zastosowano metodę elastooptyczną. Na podstawie uzyskanych wyników wyznaczono statystyki podstawowe, w tym średnie oraz odchylenia standardowe. Do analizy porównawczej wartości średnich użyto testu Tukeya HSD na poziomie istotności α = 0,05. Średnia wartość naprężeń skurczowych podczas sieciowania ortodontycznych systemów adhezyjnych wynosiła od 7,2 do 11,5 MPa.

2

Adhesion between orthodontic bracket and dental ceramics

Malkiewicz Konrad, Krasowski Michał, Bartczak Jakub, Radziejewska Marta, Janas-Naze Anna, Horodyska Estera

Polimery

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2023

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Vol. 68, nr 7-8

371--377

EN

The strength of the connection between orthodontic brackets and sandblasted dental ceramics was evaluated. The strength of the bracket-ceramics connection was determined in four time intervals. Based on the obtained results, basic statistics were calculated. For the comparative analysis of average values, the following were used: ANOVA analysis of variance and Tukey’s HSD post-hoc test at the significance level of α = 0.05. The statistical analysis performed did not show any influence of the method of surface treatment (with sanding, without sanding) between orthodontic brackets and ceramics. At the same time, it has been shown that with samples storing time in aqueous environment, the quality of the connection decreases significantly, regardless of the surface treatment method used.

PL

Zbadano wytrzymałość połączenia zamków ortodontycznych z ceramiką dentystyczną poddaną piaskowaniu. Wytrzymałość połączenia zamek-ceramika wyznaczono w czterech przedziałach czasowych. Do analizy porównawczej wartości średnich zastosowano m.in. analizę wariancji ANOVA oraz test post - hoc Tukeya HSD na poziomie istotności α = 0,05. Przeprowadzona analiza statystyczna nie wykazała wpływu metody obróbki powierzchni porcelany dentystycznej (z piaskowaniem, bez piaskowania) na jakość połączenia zamków ortodontycznych z ceramiką. Jednocześnie wykazano, że wraz z upływem czasu przechowywania próbek w środowisku wodnym, istotnie zmniejsza się jakość połączenia, niezależnie od stosowanej metody obróbki powierzchni.

3

Stress relaxation phenomena in polymeric orthodontic ligatures

Milewski Grzegorz

Engineering of Biomaterials

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2021

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Vol. 24, no. 162

2--6

EN

Elastomeric products are applied in orthodontics mainly as elastic ligatures or chains and have become an alternative to wire ligation made of titanium alloy or stainless steel. Despite their popularity among the dentists and undoubtful advantages, some essential warnings are being raised regarding the degree of load loss. This relaxation phenomenon seems to be a dominant feature in the time-dependent behaviour of those elements in orthodontic procedures, such as dentition corrections or teeth extrusions. The aim of the paper was to examine and analyse the rheological properties of biocompatible orthodontic elastomeric ligatures. Five different polymeric orthodontic ligatures were examined in the following experiments: a simple relaxation test, relaxation simulating orthodontic extrusion and the two-steps relaxation process, which stands for so-called ‘secondary tightening’, resulting in the increase of the orthodontic force. The results of the relaxation experiments proved that among various descriptions of that phenomenon, the power-law descriptions fit the best time-dependent behaviour during orthodontic procedures. Power-law models give the most intensive initial relaxation, which is characteristic for elastomeric ligatures. The obtained results and analyses allow precise control of the treatment progress in the orthodontic extrusion procedure.

4

Pure intrusion of a mandibular canine with segmented arch in lingual orthodontics: A numerical study with 3-dimensional finite element analysis

Thote A. M., Sharma K., Uddanwadiker R. V., Shrivastava S.

Biocybernetics and Biomedical Engineering

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2017

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Vol. 37, no. 3

590--598

EN

Objective: Approximately 50% patients with a deep bite possess anatomically extruded mandibular canines. The objective of this study was to specify the required toe (θ) of the vertical segment of a cantilever from the distal aspect to achieve pure intrusion of a mandibular canine with a segmented arch in lingual orthodontics. Additionally, the optimum magnitude of the required intrusive force by a cantilever was determined assuming non-linear, hyper-elastic behaviour of periodontal ligament (PDL). Methods: The geometrical model of a mandibular canine tooth was developed and the mathematical equation was devised to evaluate θ (positive value: toe-in, negative value: toe-out) based on certain input parameters. To verify this numerical study by finite element analysis (FEA), total eight different positions of point of force application (Pf) on bracket top (occlusal) surface were considered based on different values of input parameters. Results: The results were displayed in terms of nature of tooth movement and Von-Mises (equivalent) stresses generated in the PDL. Additionally, the optimum magnitude of the required intrusive force within the biological limit of a mandibular canine was determined from FEA considering the strength of PDL and factor of safety. Conclusions: The numerical study was developed to compute the value of required toe angle (θ) of the vertical segment of a cantilever for different morphologies of a mandibular canine as well as different positions of Pf. From FEA, the optimum range of an intrusive force within the biological limit of a mandibular canine was found to be 20–30 g.

5

Transparent orthodontic archwires: A systematic literature review

Mikulewicz M., Gronostajski Z., Wielgus A., Chojnacka K.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 3

651--657

EN

Objective: The objective was to perform a systematic literature review to report the state of the art on the topic of transparent orthodontic archwires. Methods: The inclusion criteria: (1) transparent or translucent orthodontic wire, (2) production method presented, (3) physical properties tested. The exclusion criteria: (1) coated esthetic archwires, (2) repetitive publications without language limitations. Databases searched: Medline (via PubMed), Scopus, Embase and Ovid (from 1970.01.01 to 2016.02.01). Additional hand search was performed. The manual search was performed in selected orthodontic journals: American Journal of Orthodontic and Orthopedics, Angle Orthodontist, European Journal of Orthodontics (from 1995 to 2016.02.01). Results: Among 342 papers, 22 were selected for systematic review and divided into two groups: those commercially available on the market and those in research and development stage. The drawbacks associated with mechanical properties limit their widespread clinical use. Conclusions: The papers reported different materials presenting different characteristics by various methodology. For this reason it was difficult to objectively compare obtained results. Characterization of translucent archwires properties has shown that further studies are required to confirm the usefulness of this type of wires, also in clinical practice.

6

Surface analysis for signs of corrosion of fixed orthodontic appliances used in vivo

Łępicka M., Grądzka-Dahlke M.

Advances in Materials Science

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2016

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Vol. 16, nr 3(49)

5--14

EN

The objective was to evaluate and assess the surface quality of fixed orthodontic appliances after intraoral usage for several months. Nine sets of orthodontic brackets by three different manufacturers and twelve archwires differing in chemical composition were analyzed in a scanning electron microscope with an energy dispersive X-ray analyzer for signs of corrosion. Obtained results showed that the majority of the evaluated appliances displayed no traces of corrosion. Machining or casting defects hardly ever act as the origins of corrosion processes. However, some samples displayed signs of corrosion of a galvanic and pitting nature. The authors claim, that despite the surface defects, most of the appliances were able to retain the desired corrosion resistance, although in some cases these flaws could act as the origin of corrosion processes.

7

Biomechanical analysis of asymmetric mesio-distal molar positions loaded by a symmetric cervical headgear

Kizilova N., Geramy A., Romashov Y.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 4

97--106

EN

Purpose: The plane 2d model and 3d finite element model of the headgear attached to two molars with different mesio-distal location are studied to show the asymmetric mechanical effects produced by symmetrically loaded headgear. In daily dental practice the asymmetrical location of molars is usually ignored. Methods: Six 3D finite element models of a symmetric cervical headgear were designed in SolidWorks 2011. The models showed symmetric molar position (model 1), 0.5 to 2 mm of anterior-posterior molar difference (models 2-5) and a significant asymmetry with 10 mm of difference in the locations (model 6). The head gear was loaded with 3N of force applied at the cervical headgear. The forces and moments produced on terminal molars are assessed. Results: It is shown the difference between the forces acting at the longer and shorter outer arms of the headgear increases with increase in the distance. The significant numeric difference in the forces has been found: from 0.0082 N (model 1) to 0.0324 N (model 5) and 0.146 N (model 6). These small forces may produce unplanned distal tipping and rotation of the molars around their vertical axes. The most important funding was found as a clockwise yaw moment in the system when is viewed superio-inferiorly. The yaw moment has been computed between -0.646 N•mm (model 1) and -1.945 N•mm (model 5). Conclusions: Therefore even small asymmetry in location of molars loaded by a symmetric cervical headgear will produce undesirable move-ment and rotation of the teeth that must be taken into account before applying the treatment.

8

Safe rebuilding of the periodontal loss an experimental study

Minch L. E., Słowiński J. J., Scigala K., Będziński R., Kawala B.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2015

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Vol. 63, nr 2

527--532

EN

This study aimed at the simulation of bone tissue remodeling within a bone defect with the utilization of the finite element method (FEM), enabling - via elaborated application - objective evaluation of orthodontic forces which positively influence periodontium in vivo. The initial position of each bracket on the passive archwire was registered, and then a geometrical and discretemodel of the appliance was created automatically. Assessment of the dental scans obtained using cone beam computed tomography (CBCT) allowed evaluation of the range of bracket displacement: from the initial position to the final one achieved on the active archwire. Those displacements established terminal conditions in the finite element analysis, enabling calculation of orthodontic force levels. An individual design of a tooth with periodontal ligaments and the periodontal defect subsequently loaded with the determined forces allowed simulation of bone remodeling according to Carters adaptation process. Mainly, the bone apposition processes took place in the central part of the periodontal defect, in proximity of the alveolar ridge. However, FEM application in the analysis of bone tissue regeneration within bone defects enables precise evaluation of the achieved changes, therefore allows determination of orthodontic forces positively influencing periodontium in vivo.

9

Atomic density of elements on the surface of orthodontic bands

Chojnacka K., Wołowiec P., Mikulewicz M.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 4

971--976

EN

The study was performed on new and used (from in vitro and in vivo experiments) orthodontic bands by using SEM-EDX technique. The bands were retrieved from earlier experiments: in vitro tests, in which the bands were incubated in a continuous flow system with various media: artificial saliva, lysozyme, orange juice and Coca Cola®. The bands were also retrieved from previously conducted in vivo tests on animals (pigs) and humans (patients). The micrographs of bands were presented as well as their chemical composition, reported in terms of atomic density. The bands that were used showed a significant contribution of oxygen as compared to brand new ones, and the contribution of Fe and Ni decreased, whereas the Cr contribution remained unchanged. The elements were inter-correlated. An antagonistic, statistically significant dependence was found between Fe and O, as well as between Fe and Cr. This could signify that that protective passivation layer of Cr2O3 was formed, which did not fully protect Ni and Fe from dissolution.

10

Możliwości łączenia zdefektowanych drutów z pamięcią kształtu

Kapustka K., Hajduga M.

Problemy Nauk Stosowanych

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2014

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T. 2

109--118

PL

Wstęp i cel: Praca została poświecona próbie reperacji drutów NiTi, które z różnych przyczyn uległy uszkodzeniu i deformacji. W dotychczasowej literaturze, Autorzy nie napotkali na informacje dotyczące reperacji elementów wykonanych z materiału z pamięcią kształtu. Połączeń dokonano metodą spawania w osłonie argonu, lutowania, oraz zgrzewania. Zakres pracy obejmuje badania metalograficzne makro i mikroskopowe struktury oraz mechaniczne: statyczną próbę rozciągania, pomiar twardości spoiny. Materiał i metody: Do badań zostały wytypowane druty ortodontyczne z pamięcią kształtu firmy Rematitan-Dentaurum®, oraz Nitanium-Ortho-Organizers®. Do obserwacji makroskopowych wybrano najbardziej charakterystyczne próbki uzyskane metodą różnego połączenia drutów NiTi. Badania spoin dokonano za pomocą mikroskopu stereoskopowego przy powiększeniu 7.5x. Wyniki: Metalografia makroskopowa - wniosła rzetelne informacje o kształcie i wielkości spoin. Badania mikroskopowe natomiast pozwoliły ocenić ciągłość połączenia - linię zwarciaprzylegania drutów NiTi w aspekcie różnych połączeń. Wniosek: W kontekście badań wytrzymałościowych najbardziej właściwą metodą reperacji drutów NiTi jest spawanie ewentualnie lutowanie. Mniejsza twardość spoiny skutkuje podwyższoną plastycznością połączenia.

EN

Introduction and aim: The paper was dedicated to try to repair NiTi wires, which for various reasons have been damaged and deformed. In the prior literature, the Authors have not found the information on repairing components made of a shape memory material. Connections made by welding argon, soldering and welding. The scope of the paper includes studies of macro and microscopic metallographic structure and mechanical: the static tensile test, hardness measurement of the weld. Material and methods: The study had been selected orthodontic wires, shape memory company Rematitan-Dentaurum ®, and Nitanium-Ortho Organizers ®. To observe the most characteristic macroscopic were selected samples obtained by using the different connections NiTi wires. Weld testing was performed using a stereoscopic microscope at a magnification of 7.5x. Results: The macroscopic metallography has been brought some reliable information about the shape and size of welds. But microscopic study allowed to evaluate the continuity of the connection - the line short-adhesion NiTi wires in terms of different connections. Conclusion: In the context of endurance tests, the most appropriate method of repair NiTi is wire welding or soldering. The smaller the hardness of the weld resulting in increased plasticity connection.

11

A tensomeric and planimetric evaluation of the durability of the bond between an orthodontic bracket and enamel

Pawlus B., Dyszkiewicz A., Špidlen M.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 4

33--42

EN

The development of orthodontics has improved thanks to the introduction of adhesives which are physically and chemically akin to tooth enamel and brackets. These materials often fall short of the required durability standards. The objective was to evaluate the real strength of the adhesives and to introduce a proprietary device, generating multiple vectors of strength between dental brackets and the surface of enamel. 11 types of adhesive materials have been studied. 990 applications have been made using removed teeth, followed by a randomised creation of 11 groups containing 90 samples each. The threshold values of the strength needed to break the brackets off were determined in torsional, shear and tension strength tests. A comparison between tensometric and planimetric methods was made by means based on ARI index. Resistance was highest for torsional stress, weaker for shear stress and the weakest for tension stress. A correlation was found between tensometric results. The study attempted to systematise the methodology of direct tests.

12

Nowy sposób oceny biokompatybilności materiałów stosowanych w ortodoncji w badaniach na świniach jako zwierzętach modelowych

Mikulewicz M., Chojnacka K., Janeczek M., Szymkowski J., Chrószcz A., Wilk M., Cieplik J., Wołowiec P.

Przemysł Chemiczny

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2012

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T. 91, nr 5

896-899

PL

Przedstawiono założenia nowego sposobu oceny biokompatybilności materiałów stosowanych w ortodoncji w badaniach na świniach jako organizmie modelowym. Badania na zwierzętach umożliwiają jednoczesne pobranie inwazyjnych i nieinwazyjnych biomarkerów narażenia na metale toksyczne i określenie w ten sposób, czy dochodzi do ich akumulacji w tkankach wewnętrznych. Skonstruowano nowe płytki doświadczalne symulujące aparaty ortodontyczne i zamontowano w pyskach świń (na wewnętrznej stronie policzka) w doświadczeniu pilotowym. Na podstawie analizy post mortem zostaną wybrane tkanki-biomarkery narażenia na metale toksyczne. Na podstawie wyników doświadczenia pilotowego zostanie zaplanowane i przeprowadzone doświadczenie właściwe na 12 świniach doświadczalnych i 12 kontrolnych.

EN

A new method for assessing the biocompatibility of materials used in orthodontics in the pig as a model organism was developed. Exptl. plates simulating orthodontic appliances were fixed in a pig snout (2 a pig) on the internal side of the cheek to study the exposure to toxic metals. No differences between expt. and control animals in growth rate and health were obsd.

13

Instalacja do oceny stopnia uwalniania jonów metali ze stopów w warunkach in vitro

Wołowiec P., Mikulewicz M., Chojnacka K.

Przemysł Chemiczny

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2012

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T. 91, nr 5

1074-1077

PL

Przedstawiono koncepcję instalacji do oceny stopnia uwalniania jonów metali w warunkach in vitro ze stopów stali nierdzewnej stosowanych w ortodoncji. Skonstruowana aparatura składa się z termostatowanego szklanego reaktora, łaźni wodnej z obiegiem zewnętrznym, pompy perystaltycznej oraz mieszadła magnetycznego z funkcją grzania i kontrolą temperatury. Konstrukcja reaktora umożliwia symulację przepływu śliny, dzięki czemu w możliwie bliski sposób zostaną odwzorowane warunki panujące w jamie ustnej. W badaniach zostanie przeprowadzona ocena uwalniania jonów metali z aparatów ortodontycznych z wykorzystaniem różnych ekstrahentów.

EN

A review, with 31 refs., of construction materials used in orthodontic appliances and methods for testing their corrosion resistance in saliva. New test stand consisting of a thermostated glass reactor, water bath with an external circulation, peristaltic pump and a magnetic stirrer with heating function and temp. control was designed and constructed to study the metal ion leaching from stainless steel and nonferrous alloys. The program of the study was outlined.

14

Sposoby oceny efektów korozji materiałów stosowanych w ortodoncji

Mikulewicz M., Chojnacka K.

Przemysł Chemiczny

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2011

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T. 90, nr 4

606-609

15

Development of rolling mill for rectangular orthodontic wires production

Totten G. E., Filho A. I., Gouvéa C. A. R., Neto A., Casteletti L. C.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 1

450-455

EN

Purpose: In orthodontic treatments, wires of different metallic alloys are used for alignment, leveling, correction of the molar position, space closing, finish and retention. The purpose of the paper is the characteristics of austenitic stainless steel wires, with a square traverse section, which were produced using a rolling mill built for this purpose, are presented here. Design/methodology/approach: With respect to finish and retention, these wires are responsible for adequate positioning of the upper teeth on the lower teeth. Wires that are subjected to incisor torque require high resistance and stiffness. For this, wires of rectangular austenitic stainless steel are used due to high modulus of elasticity and good corrosion resistance in the oral environment. Because of the rectangular geometry, wire production requires process development suitable for industrial scale manufacture with geometric characteristics and mechanical properties better adapted to the use conditions. Findings: To obtain wires with such characteristics, a rolling mill was developed for the production of rectangular wires by a rolling process with the objective of reducing cost of the cold drawing process that is currently used which utilize complex and expensive wire-drawing dies. In addition to the rolling process itself, wire deformation, microhardness, tension and bend tests were also performed. Research limitations/implications: A rolling-mill was built that successfully produced dental wires within acceptable tolerances and physical/mechanical properties.These wires exhibited excellent hardness and tensile strength, although slightly less than analogous commercial wires. It is expected that this problem are corrected by using initial wires with a higher hardness, since this property is directly related with the tensile strength. Originality/value: In these tests, wire geometry, surface finish and mechanical properties were successfully adapted for use in orthodontic treatments.