Dubina difuzije organskih molekula u gleđnom tkivu kod pasa

The objective of this study was to evaluate the extent of diffusion of organic molecules in the enamel tissue, of permanent teeth. The experimental study was performed in vivo on dogs. To the experimental dogs the molars on the right side of the lower jaw underwent enamel tissue reduction without additionally placing any tooth protection. Teeth on the left side of the lower jaw were left intact thus representing the control. After 12 months animals were sacrificed, experimental and control teeth extracted and the study of diffusion in vitro carried on. For that purpose an organic spin marker 4-amino - 2,2,6,6,-tetramethyl-piperdinyl 1-oxi (4-Amino-Tempo) was selected. The property of this marker is that it contains a nitroxide radical which is stable in a neutral and base environment, and due to the unbound spin of the free radical it is highly suitable for the electronic paramagnetic resonance method (EPR). Studies on the diffusion of organic spin markers in the enamel tissue are performed by submerging the prepared tooth in a water solution containing the marker substance. From the intensity of the EPR spectrum filmed after tooth withdrawal from the water solution, distribution diffusion time and penetration depth of marker molecules were established. Coefficients of organic spin marker diffusion and saturation concentrations of marker molecules in the enamel were determined. The observed variations in the area! and time for distribution of diffused molecules were explained by the binding possibility of the NO-radical from the marker molecule to the enamel tissue. The results of the experiment contained in this work contribute to a better understanding of the spin marker organic molecule movement through the enamel tissue which is controlled by the mechanism of diffusion and chemical bonding of the marker molecule to the enamel structure. The results of the experimental research also indicate the harmful effects of leaving the enamel tissue without protection.U ovom radu prikazani su rezultati dubine difuzije organskih molekula u gleđnom tkivu stalnih zuba. Eksperimentalna istraživanja in vivo vršena su na psima. Na molarima desne strane donje vilice, kod svih životinja eksperimentalno je izvršena redukcija gleđnog tkiva, bez postavljanja zaštite, dok su zubi leve strane mandibule ostali intaktni i predstavljali su kontrolnu grupu. Period in vivo je trajao 12 meseci, posle čega su životinje žrtvovane, eksperimentalni I kontrolni zubi izolovani I nastavljeno ispitivanje procesa difuzije in vitro. U te svrhe izabran je organski spinski marker 4-amino-2,2,6,6-teramentil-piperidinil-1-oksi (4-Amino Tempo). Osobina ovog markera je da ima u svom sastavu nitroksidni radikal koji je stabilan u neutralnoj i baznoj sredini, a zbog nesparenog spina slobodnog radikala veoma je pogodan za istraživanja metodom elektronske paramagnetne resonance

Ispitivanje mogućnosti vezivanja organskih molekula u strukturi kristala gleđnog tkiva psa

The main objective of this paper is to determine the possibilities of binding organic molecules to the enamel crystal structure. The experimental study in vivo was performed on maxillar molars in dogs. Time in vivo was 12 months after which animals were executed. All intact teeth were extracted and the study of the enamel crystal structure was continued in vitro. After treating the enamel tissue with the solution of organic spin marker 4-Amino-Tempo, the follow-up of the changes of values of the apatite crystal unit cell parameters was done by X-ray diffraction. The following conclusions may be reached after evaluation of the obtained results: in addition to the process of diffusion through the interprysmatic space of the enamel tissue, the organic molecules also play a crucial role in the changes of the crystal grid size, due to binding of organic parts of molecules in the enamel crystal structure. Permanent oscillations of the existing oxygen bonds in the enamel crystal structure have been determined every few weeks and depend on the process of substitution and resubstitution of OH ions by ions from organic and inorganic molecules and various dental materials. The local application of the fluorine based preparations on permanent teeth must be repeated every two months due to breakedown of oxygen bond and resubstitution.Osnovni cilj ovog rada je bio ispitivanje mogućnosti vezivanja organskih molekula u strukturi kristala gleđnog tkiva. Eksperimentalna istraživanja in vivo vršena su na maksilarnim molarima pasa. Nakon isteka perioda od 12 meseci životinje su žrtvovane, svi zdravi molari izvađeni i nastavljeno je ispitivanje kristalne strukture gleđnog tkiva in vitro. Korišćena je metoda difrakcije X zrakova koja u okviru kristalografskih analiza jedino ima toliku osetljivost da se mogu uočiti i najmanje promene u dimenziji kristalne rešetke gleđnog tkiva tretiranog vodenim rastvorom organskog spinskog markera 4-Amono - Tempo. Na osnovu rezultata obavljenih istraživanja zaključeno je da organski molekuli, pored procesa difuzije kroz interprizmatične prostore gleđnog tkiva, igraju presudnu ulogu i u promenama dimenzija kristalne rešetke zbog vezivanja organskih delova molekula u strukturi kristala gleđi. Permanentne oscilacije broja difundovanih molekula markera u gleđi, ukazuju na proces njihovog vezivanja za strukturu gleđi koja na svakih nekoliko nedelja predstavlja supstituciju i resupstituciju OH jona iz kristalne rešetke gleđi sa organskim, neorganskim ili česticama iz nekih lokalno aplikovanih dentalnih materijala. Lokalno aplikovani preparati na bazi fluora moraju se svaka 2 meseca ponovo postavljati na gleđno tkivo stalnih zuba zbog resupstitucije i izlaska jona fluora iz kristalne rešetke apatita

Određivanje boje zuba kod pasa

Tooth color depends on hard tooth tissue structures, above all dentine, and is genetically determinated. Nutritive habits and nutrition patterns during the lifetime can influence the change of crystal structure of enamel and dentine and consequently tooth color. The purpose of this research is to determine the color of dog teeth and to compare it to human tooth color. Standardized color key was used, thus overcoming all three color parameters: main color - hue, satiate - chroma and brightness - value. The obtained results show that both colors of dog and human teeth belong to the same spectrum. Dog teeth more frequently have a darker color which can be connected to the fact that their teeth are more worn and consequently a more intensive diffusion process is undergoing due to the changes in crystal structure because of the newly formed bondings of organic molecules into the crystal structure of the enamel.Boja zuba zavisi od sastava tvrdih zubnih tkiva, pre svega dentina i genetski je određena. Obrazac ishrane i nutritivne navike mogu u toku života putem difuzije uticati na promenu kristalne strukture gleđi i dentina a posledično i na boju zuba. Cilj rada je utvrditi boju zuba pasa i uporediti je sa bojom zuba ljudi. Korišćen je standardizovan ključ za boje kojim je moguće obuhvatiti određivanje sva tri parametra boje: osnovnu boju - hue, zasićenost - chroma i svetlinu - value. Dobijeni rezultati pokazuju da boja zuba i pasa i ljudi u najvećem broju slučajeva pripada istom spektru. Kod pasa su zastupljenije tamnije nijanse, što se dovodi u vezu sa većom abradiranošću površina njihovih zuba i intenzivnijom difuzijom i promenama dimenzija kristalne rešetke zbog vezivanja organskih delova molekula u strukturi kristala gleđi

Ispitivanje kermetskih namenskih ispuna na retencionim zubima pokretne parcijalne skeletirane proteze

The aim of the study was to describe the clinical process of setting the purpose filling on abutment teeth, after finishing the removable partial dentures. The aim was also to investigate the use of cermet glass-ionomer cement for the purpose filling in the abutment teeth for removable partial dentures, as well as to investigate the surface of the purpose filling. For the clinical evaluation of purpose filling slightly modified criteria according to Ryg's were used in 20 patients with different type of edentulousness. Changes occurring on the surface of purpose filling have been experimentally established by the method of scanning electron microscopy on the half-grown third molars in seven patients. It could be concluded that cement glass-ionomer was not the appropriate material for the purpose fillings in abutment teeth for removable partial dentures.Cilj rada je bio da se opiše klinički postupak postavljanja namenskih ispuna na retencione zube posle izrade parcijalne skeletirane proteze i klinički proceni stanje, a takođe analiziraju promene nastale na spoljašnjoj površini namenskih ispuna od doziranog kermet glas-jonomer cementa preko kojih su se nalazili elementi parcijalne skeletirane proteze. Za kliničku procenu stanja namenskih ispuna korišćeni su nešto izmenjeni kriterijumi po Ryge-y kod 20 osoba različitog tipa krezubosti. Promene nastale na površini ispuna eksperimentno su utvrđene metodom skenirajuće elektronske mikroskopije na poluimpaktiranim trećim molarima kod 7 osoba. Za namenske ispune neophodno je koristiti samo materijale koji imaju visoku otpornost na mehanička opterećenja i abrazivnost. Kermet glas-jonomer cementi su nepouzdan materijal za upotrebu na retencionim zubima usled progresivnog opadanja kvaliteta ispuna i pojave destruktivnih promena na površini sa uočenim pukotinama i defektima posle opservacionog perioda od 36 meseci

Mesiodens and paramolar in the medieval age skeletal remains

Evolution as in all segments of human behavior and existence has left traces on human teeth. The aim of this study was to determine the frequency of the supernumerary teeth in skeletal remains found at the archeological site Stara Torina and SEM evaluation of the changes on the supernumerary teeth. The study included 90 skulls and 81 jaws of both sexes with average age 20-60 years. Supernumerary teeth were prepared for SEM for analyzing dental tissues. Six supernumerary teeth were found, among them five mesiodensand one paramolar. The frequency of hyperdontia in these skeletal remains is 2,1%. Mesiodens is different morphologically from the incisor it replaced and took part in occlusal contacts during mastication. Paramolar is different morphologically from molar teeth and it did not take part in occlusal contacts during mastication because of its low adherence for bone tissues and small dimensions

Opravdanost formiranja aktivnih protetskih segmenata

The aim of this paper was to examine the justification of forming active prosthetic segments on the abutment teeth for the incline of the elements of removable partial denture. Methods. The investigation was performed during 3-years observational period, at the Prosthodontic Clinics of Belgrade University Dental School, and the Military Medical Academy (MMA). During the mentioned observation period two groups of 200 patients with different kinds of edentulousness were analyzed, indicated for the design of metal frame removable partial dentures (MFRPD) with cast clasps. A total of 400 patients represented 50% of the sample chosen by random choice method for the determined observational period and dental institutions. Results. The evaluation of justification of the abutment teeth preparation was done during the analysis of the requirement of forming: guide planes, planes for occlusal rests, vestibular under cut, oral under cut. Conclusion. Upon the evaluation of the performed analyses the following can be concluded: during the composition of every MFRPD it is necessary to use at least two or more guide planes, depending on the type edentulousness of patients' teeth; formation of guide planes is performed in excessively high number of the abutment teeth (over 95%); during the composition of each particular MFRDP it is necessary to use as more occlusal rests as possible, at least 3, or more, which also depends on the type of patients' edentulousness; composition of the planes for occlusal rest has to be performed in almost all the patients (over 95% of the abutment teeth); vestibular planes of the abutment teeth should be prepared in over 50% of the used teeth; oral planes are prepared within the preparation of the abutment teeth for other active prosthetic segments. Conclusion. It is necessary to perform the composition of active prosthetic segments according to the plan established for the study models, both if the preparation of teeth for the adoption of MFRDP elements with clasps represents the use of an uninvasive, or an invasive dental method.Cilj rada predstavlja ispitivanje opravdanosti formiranja aktivnih protetskih segmenata na retencionim zubima za prihvatanje elemenata parcijalnih skeletiranih proteza. Metode. Ispitivanje je obavljeno u okviru opservacionog perioda od tri godine na Klinikama za stomatološku protetiku Stomatološ kog fakulteta Univerziteta u Beogradu i Vojnomedicinske akademije( VMA). Analizirano je po dve stotine pacijenata različitih vrsta krezubosti, sa postavljenim indikacijama za izradu parcijalne skeletirane proteze (PSP) sa livenim kukicama. Svih četiri stotine pacijenata predstavljaju 50% uzorak odabran metodom slučajnog izbora za dati opservacioniu period i stomatološke ustanove. Rezultati. Procena opravdanosti pripreme retencionih zuba, izvršena je u okviru analiziranja potrebe formiranja: vodećih površina, ležišta za okluzalne naslone, vestibularne podminiranosti i oralne podminiranosti. Prilikom izrade svake PSP neophodno je korišćenje najmanje dve ili više vodećih površina. Formiranje vodećih površina vrši se kod izuzetno velikog broja retencionih zuba (preko 95%). Pri izradi PSP neophodno je korišćenje što većeg broja okluzalnih naslona, (najmanje tri i više), što svakako takođe zavisi od vrste krezubosti pacijenta. Formiranje ležišta za okluzalne naslone mora se izvesti kod skoro svih pacijenata (preko 95% retencionih zuba), a vestibularne površine retencionih zuba trebalo bi pripremiti kod preko 50% korišćenih zuba. Oralne površine se pripremaju u okviru pripreme retencionih zuba za ostale aktivne protetske segmente. Zaključak. Bez obzira da li priprema zuba za prihvatanje elemenata PSP sa livenim kukicama predstavlja korišćenje jedne od neinvazivnih ili invazivnih stomatoloških metoda, obavezno je izvršiti formiranje aktivnih protetskih segmenata i to prema planu postavljenom na modelu za studije

Biomechanical interactions between bone and metal-ceramic bridges composed of different types of non-noble alloys under vertical loading conditions

The purpose of this study was to compare the mechanical properties of three metal-ceramic bridges of different types of dental alloys and to present and evaluate the possible biomechanical interactions between a marginal bone and metal-ceramic bridges during vertical loading. The research was done as an experimental study. A mandible with an intact anterior region was used. The preparation of the remaining teeth for receiving three types of porcelain-fused-to-metal (PFM) restorations was performed. Vita VMK 95 was used for all three metal-ceramic restorations. These three metal-ceramic bridges composed of different alloys, nickel and non-nickel, served as different models: the Niadur-nickelferous model, the Wiron 99-nickel model and the Wirobond C-cobalt-chrome model. The maximum compressive strain of 5% for all three virtual models is observed in the region of central incisors. The Niadur model has the lowest mean strain (2.62%) in comparison with the other two models. The mean strain of Wiron 99 is lower, by 0.10%, than the mean strain of the Wirobond model. Biomechanical behavior of the presented models caused by the vertical-loading conditions is explained as an interaction between the marginal bone and the metal-ceramic bridges. All of them, nickel and non-nickel models, indicate a similar strain (deformation) distribution; however, from the biomechanical perspective, Niadur is more favorable than the other two materials

Analiza deformacija donje vilice optičkom metrologijom

Background/Aim. New optical stereometric methods based on both contact and noncontact mechanisms for displacement measurement have become common methods in biomechanical behavior research of biomaterials, bone and soft tissue. The aim of this study was to register and measure possible deformations of the lower jaw (mandible) with the intact dental arch using optical metrology method. Methods. The system for full field measurement of deformations (strains) comprised of two digital cameras for a synchronized stereoview of the specimen, and the Aramis software. Results. The maximum mandibular bone strains were measured in the regions of the lower first premolar and the lower second molar. In the action force of 500 N simulated in the region of the first lower premolar the intensity of deformation was 86 μm. The value of maximum strain in the bone around the molars was 24 μm for the force of 500 N acting on the second lower molar. When it comes to premolars, 3-5 times stronger deformation was observed in the region of the first lower premolar, compared to the deformation values of the second lower premolar area. Conclusion. Under loading of the applied forces the measured strains were in the elastic deformation area, meanning that the dependence of force and deformity is linear. The highest values of strain measurements obtained by the optical method were found in the jaw bone tissue around the loading teeth, and the bony regions of the triangle and mental region. According to the obtained results from the Aramis processing software it can be concluded that this method is applicable in a variety of biomedical research.Uvod/Cilj. Nove optičke stereometrijske metode koje se zasnivaju na kontaktnim i nekontaktnim mehanizmima za merenje zapremine postaju uobičajene metode u istraživanju biomehaničkog ponašanja biomaterijala, koštanog i mekog tkiva. Cilj ove studije bio je da se optičkom metodom merenja registruju i izmere eventualne deformacije koštanog fundamenta donje vilice sa intaktnim zubnim nizom i da se, ujedno, prikažu mogućnosti primene optičke metrologije u istraživanjima u stomatologiji. Metode. Sistem za merenje deformacija ispitivane donje vilice sa intaktnim zubnim lukom obuhvatio je dve digitalne kamere koje obezbeđuju stereosinhronizovani prikaz primerka, i softver Aramis. Rezultati. Najveće deformacije koštanog tkiva donje vilice izmerene su u regionu donjeg prvog premolara i donjeg drugog molara. Pri delovanju sila od 500 N za region prvog donjeg premolara veličina deformacije bila je 86 μm. Vrednost maksimalne srednje deformacije u koštanom sistemu oko molara iznosila je 24 μm pri delovanju sile od 500 N na drugi donji molar. Kada su u pitanju premolari, 3-5 puta jače deformacije uočene su u regionu prvog donjeg premolara, nego u predelu drugog donjeg premolara. Zaključak. Prilikom delovanja primenjenih sila deformacije se nalaze u elastičnom deformacionom polju, a međusobna zavisnost sile i deformacije ima linearan karakter. Najveće vrednosti deformacija dobijene optičkom metodom merenja registruju se u koštanom tkivu donje vilice koja je u neposrednom kontaktu sa zubima koji se opterećuju, kao i u koštanim regionima zakutnjačkog trougla i bradnog (mentalnog) otvora. Na osnovu analize rezultata dobijenih primenom softvera Aramis može se reći da postoje mogućnosti primene ove metode u različitim biomedicinskim istraživanjima

Ispitivanje kermetskih namenskih ispuna na retencionim zubima pokretne parcijalne skeletirane proteze

The aim of the study was to describe the clinical process of setting the purpose filling on abutment teeth, after finishing the removable partial dentures. The aim was also to investigate the use of cermet glass-ionomer cement for the purpose filling in the abutment teeth for removable partial dentures, as well as to investigate the surface of the purpose filling. For the clinical evaluation of purpose filling slightly modified criteria according to Ryg's were used in 20 patients with different type of edentulousness. Changes occurring on the surface of purpose filling have been experimentally established by the method of scanning electron microscopy on the half-grown third molars in seven patients. It could be concluded that cement glass-ionomer was not the appropriate material for the purpose fillings in abutment teeth for removable partial dentures

Applicability of a Serbian version of the “Oral Impacts on Daily Performance (OIDP)” index - assessment of oral health-related quality of life

Background/Aim. The Oral Impacts on Daily Performance (OIDP) is a well-known psychometric test used internationally to assess the oral health-related quality of life. The interview and self-administrated questionnaire both assess the degree to which oral health problems have affected the life of the participants over the previous 6 months. The aim of this study was to translate the OIDP index into Serbian and to assess its reliability in practice as its initial verification in the Serbian speaking area. Methods. Following an internationally established methods, the OIDP scale was translated using standardized methodology that consisted of forward translation, pilot study and backward translation. Results. A pilot study was carried out with 44 respondents (24 males i 20 females) using a preliminar Serbian version of the OIDP index. All patients were aged over 65 years. A total of 68.2% of the participants replied that they had at least one OIDP impact on daily life in the past 6 months. These troubles were most prominent during eating (47.7%) and speaking (36.4%), but there is a little impact of troubles in the domain of psychosocial sphere. The corrected item-total correlation coefficients for all items were above the minimum recommended level of 0.20 for including an item in a scale. The standardized Cronbach’s alpha coefficient was 0.75. Conclusion. Based on these results, we can conclude that this index is suitable for use in everyday practice in Serbian speaking area providing useful information required to assess oral health-related quality of life