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1

The effect of saturation by artificial saliva on the effectiveness of denture adhesives

Kasperski J., Chladek G., Żmudzki J., Lipski T.

Archives of Materials Science and Engineering

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2011

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Vol. 51, nr 1

25-32

EN

Purpose: of this examination was to evaluate the impact of saturation of adhesive materials by artificial saliva upon the generated bonding force. Design/methodology/approach: Four selected types of denture adhesives have been chosen. Measurements of bonding forces of the materials of different degree of saturation by artificial saliva have been carried out by dynamometer. The stamp covered by denture adhesive was pressed against the glass with force of 30 - 40 N and then keeping perpendicular movement against the glass, the stamp was pulled off and the joining was broken. It has been assumed that the bonding force was the equivalent of maximal pulling off force obtained in the test. The samples of different degree of saturation by artificial saliva have been exposed to tests of extensibility in a device of own design. The final denture adhesives have been put on the complete denture. It was pressed down against the denture bearing area model and next the values of retention forces were determined on a universal testing machine. Findings: Proper saturation of the samples by artificial saliva makes it possible to obtain approximate values of retention force for the majority of denture adhesives. However excessive saturation of adhesive materials can result in considerable reduction of their effectiveness. Research limitations/implications: The samples are handmade as well as part of the measurements are carried out manually and this is justified by the specific clinical conditions. Practical implications: Analysis of the impact of the level of saturation of denture adhesives by artificial saliva upon the generated bonding force highlights the need for individual selection of adhesive creams. The choice of material should be related to individual features such as secretion of saliva. It is advisable to introduce into clinical practice the option of adjusting the optimum saturation of particular denture adhesives by artificial saliva materials. Originality/value: The presented research work results allow to combine the secretion of saliva with the effectiveness of denture adhesives.

2

Kinematical analysis of mandibular motion in a sagittal plane

Margielewicz. J., Chladek W., Lipski T.

Acta of Bioengineering and Biomechanics

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2008

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Vol. 10, nr 1

9-19

EN

The paper presents a kinematical model enabling the analysis of mandibular motion in a sagittal plane. Based on the recorded trajectories of incisors, the configuration coordinates were identified. The configuration coordinates explicitly identify the position and orientation of the mandible during motion. Such values are basic to the evaluation of alteration in muscle length and to the orientation of forces in particular muscles. This paper also deals with the influence of the coefficients of the weight matrix on the character of the solutions of the configuration coordinates applied in the model study of the kinematical chain. The results of the numerical calculations obtained demonstrated that the trajectory representation was in a considerable concordance with the data recorded.

3

Influence of tongue activity on lower complete denture retention under biting forces

Żmudzki J., Chladek G., Lipski T.

Acta of Bioengineering and Biomechanics

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2008

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Vol. 10, nr 3

13-20

EN

Tongue activity constitutes a helpful factor in using complete dentures. It has not however been identified, to what extent the force of the tongue can directly stabilize the denture during the occurrence of biting forces. Dislodgement force of the denture held by the patients tongue shows a significant dependence on the tongue strength efficiency, however only few patients are able to analyze the mechanisms of using their tongues to stabilize the denture. The results of the FEM analysis show that the tongue has a strong advantageous influence on denture lateral stability during chewing and also during biting, and a slightly lower ability of counteracting the denture destabilization towards the front. The role played by the tongue in denture retention is not only that it locates the denture by means of tactile sensation but also that it supports the forces counteracting denture dislodgement.

4

Evaluation method of saliva and oral cavity mucous membrane in the aspect of holding a denture on an atrophic base

Chladek W., Lipski T., Kasperski J.

Acta of Bioengineering and Biomechanics

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2007

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Vol. 9, nr 1

53-60

EN

The paper presents application of the authors’ own method of investigating the secretion and elasticity of saliva as well as resilience of mucous membrane in evaluation of force holding the lower denture in the base. The object of research is a complete mucus lower denture cooperating with the base with a tooth-caving that is on the decline. Results of the tests of a horizontal force knocking the denture off the base were assumed as objective effectiveness evaluation criteria. Clinical investigation has been carried out in a group of 126 patients using diagnostic devices constructed according to the authors’ own conception. The elasticity of saliva was determined by measuring the length up to the break point where saliva loses elasticity, the sample volume being 55.26 mm3. The amount of saliva was determined on the basis of the area on which saliva remains and that is created by pressing the saliva with a force of 140 N by means of a 0.22 mm thick circular filter paper with a diameter of 8 mm. The filtering paper had earlier been put for 30 seconds on a mucous membrane in the area of molars. The resilience was determined on the basis of the penetrator’s cavity dented by a force of 1 N into the mucous membrane. Results obtained during the examination of a group of patients enabled an unambiguous numerical description of the characteristic features of oral cavity environment. A statistically significant influence of all investigated factors on the force necessary to knock the denture off the base has been determined. A significance hierarchy of the factors investigated as well as the ranges of variability in the parameters measured have been defined. The resilience of the mucous membrane has affected the denture knocking off force the most. It had a value of 0.4 mm up to 2.1 mm during an impact of a pointwise pressure of an average value of 0.99 mm. Then, the influence of the amount of the secreted saliva has been observed. The amount of the saliva gathered on the filter paper was expressed in terms of a “flood” area obtained after pressing the paper and amounted to 180 mm2 up to 660 mm2, with the average of 468.75 mm2. The least important factor was the elasticity determined by the break length of a saliva sample. The lengths of breakpoints measured were from 4.8 mm for saliva with a dominant serum secretion content up to 24.1 mm for saliva with a dominant mucus secretion content. The average value for the whole population examined was estimated at 14.19 mm.

5

Stress distribution in anchoring regions of posts cooperating with overdentures

Chladek W., Chladek G., Krukowska J., Lipski T.

Acta of Bioengineering and Biomechanics

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2005

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Vol. 7, nr 1

35-45

EN

The paper presents the results of model research of mechanical compatibility of selected overdenture structures. The tests based on finite elements method were conducted on flat models reflecting the areas of posts anchoring m a sagittal piane. The reference point was the structure of a prosthesis seated on ball-and-socket joints secured in tooth roots. As altemative solutions, dentures placed on two cylindrical implants supporting ball-and-socket joints were compared with a denture attached to a joint which consisted of a straight axis bar and an elastic clip as well as with a denture supported by a joint of elevated retention, built of a doubly bent axis bar and three elastic bar clips. Taking advantage of the MES Algor program functions, the diverse materiał structures of the systems investigated were modelled. Next. the reduced stresses and principal maximum stresses generated m osseous tissues, in the implants anchoring area. were determined. The value of the mechamcal stimulator decisive to the osseous tissue remodelling was assumed as au evaluatiou criterion. It was assumed that making use of patient's own tooth roots to attach implants IS an optimal solution which, in terms of mechanics, IS practically identical to the alveolodental ligament of a healthy tooth. The application of the other methods of implanted prosthesis attachment always creates a risk of undesirable changes, mostly in the upper area of post insertion into the osseous tissue. The least favourably, in the light of stresses comparison, looks the joint of a doubly refracted axis, where the probability of adverse changes of the osseous tissue in a short time is high. This indicates the necessity to carry on words in order to improve this solution characterized by good retention.

6

Experimental evaluation of occlusal forces

Chladek W., Lipski T., Karasiński A.

Acta of Bioengineering and Biomechanics

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2001

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Vol. 3, nr 1

25-37

EN

The paper presents the results of measuring the occlusion forces in the group of 163 subjects being tested. In the research, the method based on the dependence of the plastic deformity and force intending the spherical penetrator upon each other in a metal sample was implemented. The results obtained allowed us to estimate the distribution of occlusion forces along the alveolar ridge and to define the dimensions of the maximum forces applied, while biting and gnawing. The biting force between the first incisors for different angles of parting mandible was also measured.

7

Finite element analysis of mandible equilibrium depending on the way of its loading and supporting

Chladek W., Żmudzki J, Lipski T.

Acta of Bioengineering and Biomechanics

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2000

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Vol. 2, nr 1

63-69

EN

Results of FEA of mandible equilibrium and mandible without one-sided support at temporoman-ibular joint were presented. Models were loaded with occlusal forces whose values were experimentally itablished. Forces of muscles were simulated by elastic supports with an assumption that reactions ould lead to active forces generated by the system of muscles.

8

Biomechaniczne aspekty funkcjonowania rekonstrukcji uzębienia wykonanej z zastosowaniem implantów i wkładów koronowo-korzeniowych.

Chladek W., Grosman F., Ilewicz L., Lipski T.

Inżynieria Materiałowa

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1999

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R. XX, nr 3-4

196-201

PL

W pracy przedstawiono wyniki badań oddziaływania wybranych konstrukcji metalowych stosowanych w rekonstrukcji uzębienia na zmiany rozkładów w tkankach naturalnych. Wykorzystując metodę elementów skończonych, zamodelowano wpływ sił okluzyjnych na naprężenia w układzie kostnym w strefie kotwiczenia implantów stomatologicznych systemu Branemarka stanowiących filary implantoprotezy pojedynczego zęba. Analizie poddano takie czynniki, jak długość implantu oraz kierunek jego wprowadzenia. Stwierdzono istotną różnicę wytężenia tkanki kostnej w stosunku do stanu naturalnego. Uzyskane wyniki wskazują na możliwość wpływania na wielkość naprężeń poprzez odpowiedni dobór długości wszczepu. Kolejnym analizowanym sposobem przywracania wydolności narządu żucia były metody całkowitej rekonstrukcji korony zęba wykorzystujące prefabrykowane wkłady koronowo-korzenne. Przy zastosowaniu tych metod, biomechaniczne warunki pracy przyzębia nie ulegają zmianie. Zmienia się natomiast sposób obciążenia pozostałych tkanek zęba własnego. Stwierdzono, że zarówno dla zębów jednokorzeniowych, jak i wielokorzeniowych, metalowe konstrukcje poprawiające retencję materiału rekonstrukcyjnego przejmują rolę twardych tkanek zęba. Ze względu na zdarzające się przypadki pęknięcia korzenia z założonym wkładem, następujące przeważnie w wyniku urazu, przeanalizowano wpływ długości części korzeniowej wkładu na wytężenie ścianki korzenia. Stwierdzono, że zbyt bliska odległość końca wkładu od otworu fizjologicznego będzie sprzyjać mechanicznym uszkodzeniom korzenia. Wyniki przedstawiono w postaci map i wykresów naprężeń redukowanych.

EN

Investigation results of interaction of selected metal structures used in the dentition reconstruction on the changes in the stress distribution in natural tissues are presented in this article. Using the final elements method an influence of occlusion forces on stresses in the osseous system in the zone of hooking the dental implants of Branemark's system being the implantoprosthesis pillar of a single tooth has been modelled. The length of an implant and the direction of its insertion were the factors subjected to an analysis. A significant difference of the bone tissue effort was found in comparison to the natural state. the obtained results show that is possible to influence the value of stresses by an appropriate selection of the implant length. Methods of the total reconstruction of the tooth crown using prefabricated crown-root inlays were another analysed way of restoring efficiency of masticatory organ. By using those methods, biomechanical working conditions of the parodontium do not undergo changes. However, a way of loading of the other tissues of the natural tooth is changed. It has been found that for both monoradicular and multiradicular teeth, metal structures improving retention of the reconstruction material take over the function of hard tissues of a tooth. Due to cases of cracking of a root with the inserted inlay, occuring mainly as a result of trauma, an influence of the length of the radicular part of an inlay on effort of the root wall was analysed. It has been found that too close distance of the inlay end from a physiological opening will favour mechanical damages of the root. The results were presented in the form of maps and diagrams of reduced stresses.

9

Metoda badania sił zgryzu wykorzystująca deformację plastyczną próbek z blachy aluminiowej.

Chladek W., Lipski T.

Inżynieria Materiałowa

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1998

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R. XIX, nr 2

57-59

PL

W pracy przedstawiono nową metodę pomiaru sił zgryzu opartą na zależności pomiędzy wielkością odcisku w blasze aluminiowej a siłą wgniatającą penetrator w kształcie kulki. Metodę sprawdzono dokonując badań klinicznych 120 osób. Uzyskane wyniki pozwoliły na ocenę rozkładu sił zgryzu wzdłuż łuku zębowego oraz określenie maksymalnych sił pomiędzy zębami trzonowymi i przedtrzonowymi.

EN

The work presents the new method of measuring the occlusion forces and the results of investigations in a group of 120 tested subjects. In the research the method based on interdependence between the plastic deformity and force indenting the spherical penetrator in the metal sample was implemented. The obtained results allowed to estimate the distribution of occlusion forces along the alverolar ridge and define the dimensions of the maximum forces applied while biting and gnawing.