PorovnaÂnõÂ vazebneâ sõâlyadheziv pouzïõâvanyâ ch v ortodoncii Comparative studyof bond strength in adhesives used in orthodontics

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1 rocïnõâk21 ORTODONCIE PorovnaÂnõ vazebneâ sõâlyadheziv pouzïõâvanyâ ch v ortodoncii Comparative studyof bond strength in adhesives used in orthodontics *Bartøomiej Pawlus, **Dr n. med., Dr n. tech. Andrzej Dyszkiewicz, *Doc. MUDr MilosÏ SÏ pidlen, Ph.D. *Ortodonticke oddeï lenõâ Kliniky zubnõâho leâ karïstvõâ LF UP Olomouc, CÏ eskaâ Republika *Department of Orthodontics, Clinic of Dental Medicine, Medical Faculty of Palacky University, Olomouc, Czech Republic **Institut Fyzioterapie Opolske Polytechniky, Laboratorium BiotechnologieªLabiotª, Cieszyn, Polsko **Institute of Physiotherapy, Opole Polytechnics, Laboratorium Biotechnologie ªLabiotª, Cieszyn, Poland Souhrn CõÂl: CõÂlem praâ ce bylo porovnaâ nõâ a hodnocenõâ pevnosti adheziv vyuzïõâvanyâ ch k lepenõâ ortodontickyâchzaâ mkuê. Metodika: Celkem bylo hodnoceno 11 adheziv. Da le bylo kvantitativneï hodnoceno mnozï stvõâ ponechaneâ ho adheziva na povrchu skloviny prostrïednictvõâm ukazatele ARI - Adhesive Remnant Index. Studie byla provedena na 330 extrahovanyâ ch premolaâ rech rozdeï lenyâ ch do 11 skupin podle druhu adheziva po 30 vzorcõâch. Pevnost vazby byla zkoumaâ na pro kazïdeâ adhezivum ve smyku, tahu a krutu. Ke studii byly pouzïity kovoveâ zaâ mky RMOIntegra. Byl stanoven Adhesive Remnant Index pro testovanaâ adheziva. Vy sledky: StrÏednõ hodnoty ve smyku meï l nejvysï sï õâ Transbond XT, nejnizïsï õâ zõâskal No-Mix. StrÏednõ hodnoty v tahu meï l nejvysïsï õâ Medicept Light Cure, nejnizïsï õâ zõâskal Tetric flow. StrÏednõ hodnoty v krutu meï l nejvysïsïõâ Light Bond Reliance, nejnizïsï õâ zõâskal Granitec Falcon (Ortodoncie 2012, 21, cï. 1, s ). Abstract Aim: The aim was to compare and evaluate bond strength of adhesives used for orthodontic brackets attachment. Method: 11 different adhesives were tested. The amount of adhesive left on the enamel surface was quantitatively evaluated with ARI (Adhesive Remnant Index). The study included 330 extracted premolars classified into 11 groups (30 samples each) according to the type of adhesive. Bond strength of each adhesive was evaluated by shear, tensile, and torsion test. Metal brackets RMOIntegra were used. Adhesive Remnant Index was set for the adhesives tested. Results: The highest mean values in shear test were found for Transbond XT, the lowest for No-Mix. The highest mean values in tensile test were found for Medicept Light Cure, the lowest for Tetric flow. The highest mean values in torsion test were found for Light Bond Reliance, the lowest for Granitec Falcon (Ortodoncie 2012, 21, No. 1, p ). KlõÂcÏ ovaâ slova: adheziva v ortodoncii, hodnocenõâ v tahu, smyku, krutu, pevnost vazby Key words: adhesives in orthodontics; values for tension, shear, and torsion; adhesive bond strength redakce@orthodont-cz.cz

2 ORTODONCIE rocïnõâk21 U vod Pokrok a rozvoj novyâ ch adhezivnõâch materiaâ l uê k prïipevneï nõâ zaâ mkuê na zubnõâ sklovineï vyâ znamneï ovlivnil mozï nost ortodontickeâ leâcï by fixnõâmi aparaâ ty [1, 2]. Adhezivnõ materiaâ l musõâ odolat sõâle pouzï õâvaneâ v l eâ cï enõâ, kteraâ je prïenaâsï enaâ na zuby prostrïednictvõâm ortodontickyâ ch zaâ mkuê, ale i sõâle, vznikajõâcõâ prïi beï zï nyâ ch zï vyâ kacõâch pohybech. CÏ astou potõâzï õâ, kteraâ se vyskytuje v pruê beï hu ortodontickeâ l eâ cï by fixnõâm aparaâ tem, je odlepovaânõâ zaâ mkuê, zpuê sobeneâ neopatrnyâ m kousnutõâm, nespraâ vnyâ m postupem prïi lepenõâ zaâ mkuê, nebo strukturou skloviny, kterou nelze kvalitneï leptat [3]. OpacÏny efekt muêzïe zpuê sobit prïõâlisï velkaâ sõâla adheze ke sklovineï (võâce nezï MPa), kteraâ zpuê sobõâ odtrhnutõâ prismy skloviny v pruêbeï hu snõâmaâ nõâ zaâ mkuê [4,5]. Podle Bishary pevnost vazby nizïsï õâ nezï 12,75 MPa je optimaâ lnõâ a bezpecïnaâ prïi snõâmaâ nõâ zejmeâ na keramickyâch zaâ mkuê [6]. Laboratornõ vyâ zkumy zkoumajõâcõâ hodnoty vazebneâ sõâly mezi ortodontickyâm zaâ mkem a zubem ukaâ zaly, zï e dostatecïnou adhezi fixnõâch aparaâtuê zajisït'uje sõâla MPa [7]. Bylo zjisïteï no, zï e sõâla smyku v rozsahu od 1 do 3 MPa, vznikajõâcõâ v pruê beï hu l eâcï enõâ, by nemeï la zpuê sobit odtrhaâ vaâ nõâ ortodontickyâ ch elementuê [8, 9]. Je trïeba si uveï domit, zï e sõâly napeï tõâ v komplexu sklovina - adhezivum - zaâ mek, ktereâ vznikajõâv pruêbeï hu aktu zïvyâkaâ nõâ, mohou mõât vysïsï õâ hodnoty. Znalosti tyâ kajõâcõâ se vlastnostõâ jednotlivyâ ch adhezivnõâch materiaâluê jsou duêlezï itou pomuê ckou prïi vyâbeï ru odpovõâdajõâcõâch adheziv pro urcï iteâ klinickeâ prïõâpady. Pevnost spoje zaâ visõâ nejenom na adhezivnõâm materiaâ l u, ale rovneï zï na baâzi zaâ mku, povrchu skloviny a zpuê sobu lepenõâ. CõÂlem praâ ce bylo porovnaâ nõâ a hodnocenõâ pevnosti adheziv vyuzï õâvanyâ ch pro prïipevneï nõâ ortodontickyâ ch zaâ mkuê na zubech. Bylo provedeno kvantitativnõâ hodnocenõâ adheziva ponechaneâ ho na povrchu skloviny, pomocõâ ukazatele ARI - Adhesive Remnant Index []. Materia l a metoda Analy ze byly podrobeny naâ sledujõâcõâ adhezivnõâ materiaâ ly: Kompozitnõ pryskyrïice: Transbond XT (3M), Medicept Light Cure (Medicept Dental), Resilience (Ortho Technology), Light Bond (Reliance), Enlight (Ormco), No-Mix (), Tetric flow (Vivadent), ConTec Prime (), Granitec (Falcon), akrylaâtovaâ pryskyrïice Spofacryl(Spofa Dental) tak rovneïzï skloionomernõâ cement Fuji ORTHO LC (GC). Zhotovenõ vzorkuê k studii probõâhalnaâ sledujõâcõâm zpuêsobem. Bylo prïipraveno 330 extrahovanyâ ch premolaâ ruê po prïedchaâ zejõâcõâ dezinfekci preparaâ tem Incidin liquid s propanolem s vyâ jimkou sklovinneâ ho povrchu. Zuby byly po extrakci prïechovaâ vaneâ v roztoku 0,9 % NaCl Introduction The advancement and development of new adhesive materials for the attachment of brackets to enamel have a significant impact on the orthodontic treatment with fixed appliances [1,2]. Adhesive materials should resist to the force used during the treatment that is transferred on the teeth by means of orthodontic brackets, as well as to the force applied in normal mastication. A rather frequent problem occurring during the orthodontic treatment with fixed appliance seems to be the bond failure of brackets due to careless bite, incorrect technique of the brackets attachment, or due to the enamelstructure which cannot be etched correctly [3]. Another problem is represented by an excessive adhesive bond strength (over MPa) that may result in the enamel prism pull-off during the brackets removal[4,5]. Bishara says the bond strength below MPa is optimum and safe during the ceramic brackets detachment [6]. Laboratory research focused on the values of bond strength between an orthodontic bracket and a tooth proved that sufficient adhesion of fixed appliances is secured by the strength between 5.8 and 7.8 MPa [7]. The shear strength of 1 to 3 MPa, originating during the treatment, should not result in the detachment of orthodontic components [8,9]. However, we should remember that the tensile strengths within the complex enamel-adhesive-bracket, occurring during mastication, may be greater. Knowledge of characteristics of individual adhesive materials is of a great help in the selection of appropriate adhesives for different clinical cases. The bond strength depends on the adhesive materialused as well as on the bracket base, enamel surface, and the technique of attachment. The aim of our study was to compare and evaluate bond strength of adhesives used for the attachment of orthodontic brackets. The amount of adhesive remnant on the enamelsurface was evaluated quantitatively with help of ARI (Adhesive Remnant Index) []. Material and method The following adhesive materials were tested: Composite resins: Transbond XT (3M), Medicept Light Cure (Medicept Dental), Resilience (Ortho Technology), Light Bond (Reliance), Enlight (Ormco), No- Mix (), Tetric Flow (Vivadent), ConTec Prime (Denaturum), Granitec (Falcon), acrylate resin Spofacryl (Spofa Dental), glass-ionomer cement Fuji ORTHO LC (GC). Samples were prepared in the following way: 330 extracted premolars were disinfected with Incidin liquid and propanol(with the exception of enamelsur- redakce@orthodont-cz.cz 17

3 rocïnõâk21 ORTODONCIE Obr. 1: ZkousÏ ky pevnosti vazby; zleva - tah, smyk, zkrut Fig. 1: Adhesive bond strength tests; left to right - tension, shear, torsion face). The teeth were preserved in a 0.9% NaClsolution at 37 C for two weeks. Then the teeth were placed in cubes 2 cm x 2 cm x 2 cm and fixed with polyester resin Plus 7 (Novol). By random 11 groups each of 30 samples were created. The groups were assigned to the relevant method of analysis (shear, tension, torsion) and to the adhesive tested (Fig. 1). The enamelwas intact (proved by a digitalmicroscope with CMOS 2.0 megapixels, software by Micro- Capture, interface PC USB 2.0) in the place where there was a bracket base attached. There was no filling, caries or any enamel defect. The teeth enamelwas cleaned with paste containing pumice, etched for 30 seconds with 37% orthophosphoric acid, and then the teeth were washed with water and dried. Bracket base was degreased with alcoholand dried with compressed air. Adhesive materials tested were used and polymerized in accordance with the manufacturer recommendations. Polymerization lamp with a monochromatic dioda 00mW/cm 2 (Heraeus Kulzer, Translux Power Blue) was used. Metalbrackets RMO Integra.022ª were used for all adhesive materials. The testing was performed in vitro at 24 C, 60 minutes after the bracket was attached to the enamel. Thus an eventual influence of the oral cavity condition on the characteristics of polymers tested was eliminated. Study was performed with the equipment for strength of materialtesting with resistance strain gauge Vishay, model615 Tedea Huntleigh, weight meter VT 0, servomechanism by Eisel, enabling to carry out firmness static tests (shear, tension). The data obtained were sent via digital-to-analog converter to a PC computer, and the result was processed as a chart with the maximum value where the material was torn. The equipment with a scale in Newtons cerprïi teploteï 37 C podobu do 2 tyâdnuê. Pote byly umõâsteï ny v krychlõâch o rozmeï rech 2 cm x 2 cm x 2 cm, fixovaneâ pomocõâ polyesteroveâ pryskyrïice Plus 7 firmy Novol. Na hodneï bylo vytvorïeno 11 skupin po vzorcõâch. Skupiny byly prïirïazeny k odpovõâdajõâcõâ metodeï zkoumaâ nõâ (smyk, tah, krut), a zaâ rovenï ke zkoumaneâ mu adhezivu (Obr. 1). Sklovina zubu v mõâsteï, ke ktereâ bezprostrïedneï prïileâhala baâze zaâ mku, byla intaktnõâ, cozï bylo zjisïteï no digitaâ lnõâm mikroskopem s cï idlem CMOS 2,0 megapixeluê s programovyâ m vybavenõâm MicroCapture a interfejsem PC USB 2.0. Nebyla zde vyâplnïcï i zubnõâ kaz, nebo vada skloviny. Sklovina zkoumanyâ ch zubuê byla ocï isï teï na pastou s pemzou, leptaâ na 30 sekund 37% kyselinou ortofosforecï nou, oplaâ chnuta vodou a osusï ena. BaÂze zaâ mkuê byla odmasïteï na lihem a osusï ena stlacï enyâm vzduchem. PouzÏ itõâ a polymerizace kazï deâ ho ze zkoumanyâch adhezivnõâch materiaâluê byla provedena v souladu s doporucï enõâmi vyâ robce. K polymerizaci byla pouzï ita polymeracï nõâ lampa s monochromatickou diodou o vyâ konu 00mW/cm 2 firmy Heraeus Kulzer, Translux Power Blue. Pro vsï echna adheziva byly pouzï ity kovoveâ zaâ mky firmy RMO Integra.022ª. ZkousÏ ky byly provaâdeï ny in vitro prïi teploteï 24 C, hodinu po prïipevneïnõâzaâ mku ke sklovineï. TõÂm se vyloucï il prïõâpadnyâ vliv podmõânek prostrïedõâ uâ stnõâ dutiny na vlastnosti zkoumanyâ ch polymeruê. Vy zkum bylprovaâdeï n na stroji pro pevnostnõâ zkousï ky materiaâ lu s odporovyâ m tenzometrem firmy Vishay, model615 Tedea Huntleigh, meï rïicï em hmotnosti VT 0, a servomechanizmem firmy Eisel, umozïnï ujõâcõâm provaâdeï nõâ pevnostnõâch statickyâ ch zkousï ek (smyk, tah). U daje byly zasõâlaâ ny prostrïednictvõâm analogoveï cï õâslicoveâ ho prïevod redakce@orthodont-cz.cz

4 ORTODONCIE rocïnõâk21 nõâku do pocï õâtacï e trïõâdy PC a vyâ sledek byl promõâtaâ n v podobeï tabulky s maximaâ lnõâ hodnotou, ve ktereâ dochaâ zelo k prïetrzï enõâ materiaâ lu. ZarÏõÂzenõÂ, opatrïeneâ stupnicõâ v newtonech s certifikaâ tem PCA, provaâdeï l o meï rïenõâ s rychlostõâ posunu 5 mm/min. VyÂzkum kroutõâcõâho momentu bylprovaâ deï n analogovyâ m dynamometrem firmy Tohnichi FTD50CN2-S kalibrovaneâ ho v cn*m v rozsahu od 1-50, s odchylkou meïrïenõâ 0.01 cn*m. Bylo provedeno 30 pevnostnõâch zkousï ek (krut, tah, smyk) pro kazï deâ adhezivum. Po provedenyâ ch testech byly vzorky hodnoceny v optickeâ m mikroskopu vybaveneâ m kamerou a cï õâslicovyâm prïevodnõâkem obrazu, pracujõâcõâm ve zveï tsï enõâ 20x, s cõâlem kvalitativnõâho hodnocenõâ plochy odtrzï enõâ, a zvlaâsïteï, co do mnozïstvõâ ponechaneâ ho adheziva na povrchu skloviny zubu podle ukazatele ARI (Adhesive Remnant Index). Hodnocenõ ukazatele ARI bylo provedeno podle naâsledujõâcõâch kriteâ riõâ: (0) bez adheziva (1) meâneï nezï 50 % adheziva (2) võâce nezï 50 % adheziva (3) - vsï echno adhezivum na zubu s vyâ raznyâm otiskem baâzezaâ mku. K porovnaâ nõâ vyâ sledkuê pevnostnõâch testuê (tah, smyk a krut) byla pouzï ita jednofaktorovaâ analyâ za variance (ANOVA), viz (Tab. 1, 2, 3). Vy sledky V testech pro smyk meï lnejvysïsï õâ hodnotu pruêmeï rneâ meznõâ sõâly Transbond XT. NejnizÏsÏ õâ pruê meï rneâ hodnoty vykaâ zalno-mix (Tab. 1). Ve vzorku pro tah meï lnejvysï sï õâ hodnoty pruê meï rneâ meznõâ sõâly Medicept LightCure. NejnizÏsÏ õâ pruê meï rneâ hodnoty byly vykaâzaâ ny pro Tetric flow (Tab. 2). NejvysÏsÏ õâ pruê meï rneâ hodnoty pro kroutõâcõâ moment, prïi ktereâ m dosï l o k prïetrzï enõâ materiaâ lu, byly zaregistrovaâ ny u Light Bond Reliance a Transbond XT. NejnizÏsÏõ pruêmeï rneâ hodnoty projevilgranitec Falcon (Tab. 3). Hodnoty ukazatele ARI v testovanyâ ch skupinaâ ch pro tah prezentovaly veïtsï õâ rezidua adheziva ponechaneâ ho na sklovineï uveïtsï iny testovanyâch. VyÂjimkou byly pryskyrïice Spofacryl, Light Bond, Medicept Light Cure u kteryâ ch bylo nameï rïeno vysï sï õâ procento zbytkoveâ ho adheziva na zaâ mcõâch (Tab. 4). Analogicky u hodnot ARI pro smyk a krut bylo zaregistrovaâ no, zïeveïtsï ina adheziva zuê staâ vala na sklovineï.vyâ jimkou byla pryskyrïice Spofacryl, Light Bond, Medicept Light Cure, kde zuêstaâ valo adhezivum na baâzizaâ mku (Tab. 5, 6). Diskuse K lepenõâ zaâ mkuê jsou aktuaâlneï nejcï asteï ji pouzïõâvaâny plneïneâ akryloveâ pryskyrïice (formule Bis GMA). Tyto pryskyrïice jsou dostupneâ v mnoha variantaâ ch, jezï se od sebe lisï õâ hlavneï slozï enõâm a mnozïstvõâm plniva a zpuê- tified by PCA, performed measurement with the advancing speed of 5 mm/min. Torsionalmoment was tested with analog dynamometer fy Tohnichi FTD50CN2-S, scaled in cn*m within the range 1-50, measuring deviation of 0.01 cn*m. For each adhesive material30 tests (torsion, tension, shear) were performed. After the testing the samples were evaluated with optical microscope equipped with a camera and digitalconverter of image, magnification 20 x. The main objective was to evaluate the quality of the surface in the place of a tear, and the amount of adhesive left on the enamel surface according to ARI (Adhesive Remnant Index). ARI was evaluated according to the following criteria: (0) No adhesive left (1) Less than 50% of adhesive left (2) More than 50% of adhesive left (3) - all adhesive left on the tooth, expressed imprint of the bracket base. To compare the results of strength tests (tension, shear, torsion) one-factor variance analysis (ANOVA) was used (Table 1, 2, 3). Results In shear tests the highest value of the mean limit strength was recorded for Transbond XT. The lowest mean values were found for No-Mix (Table 1). In tension tests the highest value of the mean limit strength was found in Medicept LightCure. The lowest values were found in Tetric flow (Table 2). In torsion tests, during which the materialgot torn, the highest mean values were recorded for Light Bond Reliance and for Transbond XT. The lowest mean values were measured for Granitec Falcon (Table 3). In groups tested for tension strength higher ARI values were found in most tested teeth (adhesive left on enamel) with the exception of resins Spofacryl, Light Bond, Medicept LightCure - more adhesive remnants were detected in brackets (Table 4). Similarly, in groups tested for shear and torsion strength adhesives were mostly left on the enamel, with the exception of resin Spofacryl, Light Bond, Medicept Light Cure - again, more adhesive remains were found on the bracket base (Table 5, 6). Discussion For the bracket attachment filled acrylate resins (formula Bis GMA) are used most frequently. A great variety of resins is available. Individual resins differ in the composition and amount of filler and in the method of polymerization, either chemical or light-cured [11]. redakce@orthodont-cz.cz 19

5 rocïnõâk21 ORTODONCIE Tab. 1. Hodnoty sõâly v testech pro smyk u jednotlivyâch adheziv [MPa] Tab. 1. Adhesive bond strenght in shear tests for individualadhesives [MPa] shear [MPa] Tab. 2. Hodnoty sõâly v testech pro tah u jednotlivyâch adheziv [MPa] Tab. 2. Adhesive bond strenght in tension tests for individualadhesives [MPa] tension [MPa] Bond N mean SD min max Bond N mean SD min max Tetric flow Vivadent Medicept LightCure Dental Light Bond Reliance Spofacryl Spofa Dental Enlight ORMCO Transbond XT 3M No Mix Resilience Ortho Technology Gc Fuji ORTHO LC ConTec Prime Granitec Falcon TOTAL Tab. 3. Hodnoty sõâly ve krutu pro jednotlivaâ adheziva [cn*m] Tab. 3. Adhesive bond strenght in torsion tests for individualadhesives [cn*m] torsion [cn*m] Bond N mean SD min max Tetric flow Vivadent Medicept LightCure Dental Light Bond Reliance Spofacryl Spofa Dental Enlight ORMCO Transbond XT 3M No Mix Resilience Ortho Technology Gc Fuji ORTHO LC ConTec Prime Granitec Falcon TOTAL Tab. 5. Hodnoty ARI u testuê smykem Tab. 5. ARI in shear tests SHEAR [ARI] BOND N Tetric flow Vivadent Medicept LightCure Dental Light Bond Reliance Spofacryl Spofa Dental Enlight ORMCO Transbond XT M No Mix Resilience Ortho Technology Gc Fuji ORTHO LC ConTec Prime Granitec Falcon TOTAL 1 Tetric flow Vivadent Medicept LightCure Dental Light Bond Reliance Spofacryl Spofa Dental Enlight ORMCO Transbond XT 3M No Mix Resilience Ortho Technology Gc Fuji ORTHO LC ConTec Prime Granitec Falcon TOTAL Tab. 4. Hodnoty ARI u testuê tahem Tab. 4. ARI in tension tests TENSILE [ARI] BOND N Tetric flow Vivadent Medicept LightCure Dental Light Bond Reliance Spofacryl Spofa Dental Enlight ORMCO Transbond XT M No Mix Resilience Ortho Technology Gc Fuji ORTHO LC ConTec Prime Granitec Falcon TOTAL 1 Tab. 6. Hodnoty ARI u testuê pro krut Tab. 6. ARI in torsion tests TORSION [ARI] BOND Tetric flow Vivadent Medicept LightCure Dental Light Bond Reliance Spofacryl Spofa Dental N Enlight ORMCO Transbond XT 3M No Mix Resilience Ortho Technology Gc Fuji ORTHO LC ConTec Prime Granitec Falcon TOTAL redakce@orthodont-cz.cz

6 ORTODONCIE rocïnõâk21 sobem iniciovaâ nõâ polymerizace, chemicky nebo sveïtelnyâm tvrzenõâm [11]. Vazebna sõâla adheziva mezi zaâ mkem a sklovinou zaâvisõâ takeâ na konzistenci a procentoveâ m slozï enõâ leptadla a doby leptaâ nõâ, zaâ visõâ na kvaliteï povrchu skloviny, na polymerizaci adheziva, vzdaâ lenosti mezi zdrojem sveïtla a zubem. Za visõâ na tvaru, strukturïe a velikosti povrchu a materiaâ l u baâ ze zaâ mku, na prostrïedõâ uâ stnõâ dutiny, a zkusï enosti leâ karïe [12]. V klinickeâ praxi jsou sõâly, vznikajõâcõâ v pruê beï hu snõâmaânõâ zaâ mkuê, komponentou krutu, tahu a smyku [13]. PouzÏ itõâ optimaâ lnõâho adheziva zkracuje cï as naâ vsï teï vy, cozï v duê sledku snizï uje diskomfort pacienta a eliminuje riziko uvolneï nõâ zaâ mkuê [14]. PrÏi srovnaâ nõâ metodiky jednotlivyâ ch vyâ zkumuê a pouzï ityâchzaâ mkuê dochaâ zõâme k zaâveï ru, zïevyâsledky meïrïenõâ jsou rozdõâlneâ a velmi cï asto se nedajõâ porovnat [15]. Podle Eliadese [16] rychlost posunu testujõâcõâho stroje vysï sï õâ nezï 0.5mm/min. ovlivnï uje uâ rovenï zõâskanyâch vyâsledkuê. Podle Cagri and Irmak [17] pouzï itõâ halogenoveâ ho sveï tla zpuê sobuje zvyâsï enõâ vazebneâ sõâly lepidla, (pruêmeï rneï 8.35 MPa), nezï je u LED sveï tla (5.83 MPa). PodobneÏ, jak u R. Valetta I D. Prisco [13], byly zõâskaneâ statisticky vyâ znamneâ vysï sï õâ hodnoty v pruê beï hu pevnostnõâch testuê ve smyku, krutu a tahu u materiaâlu Transbond XT a nizïsï õâ u Fuji GC. DuÊ vodem odlisï nyâ ch hodnot nasï eho vyâ zkumu vzhledem k jinyâ m studiõâm bylpravdeï podobneï typ struktury baâ ze pouzïityâch zaâ mkuê. Podle Majera a Smitha 1981 [18] se vyâsledky vyâzkumu provaâdeïneâhonaruêznyâch zaâ mcõâch nedajõâ vzaâ jemneï porovnat. Jinou prïõâcï i- nou potvrzenou Wendlem i Droschlem [19] v rozdõâlech meï rïenõâ je to, zï e vazebnaâ sõâla lepenyâch zaâ mkuê vzruê staâ v pruêbeï hu prvnõâch 24 hodin. MeÏrÏenõ v nasïemvyâzkumu bylo provaâdeï no v prvnõâhodineï po lepenõâzaâ mkuê a v konsekvenci s tõâm byly zõâskaneâ hodnoty mensï õâ, nezï u vyâsïe uvedenyâch autoruê. Podle Majera a Smitha je lom mezi sklovinou a adhezivem zpuê sobenyâ spõâsï e chybami v pruêbeï hu lepenõâ zaâmkuê [20]. Ve skutecï nosti spraâ vneï provedeneâ lepenõâ zaâmkuê vytvorïõâ dostatecï nou adhezi, kteraâ podle Valletty a Prisco [13] muêzïe zpuê sobit posï kozenõâ skloviny v pruêbeï hu snõâmaâ nõâ aparaâ tu. V nasï em vyâ zkumu dvakraâ t dosï lo k posï kozenõâ prizmat skloviny v testech ve smyku u materiaâ lu Spofacryl. VyÂsledky Regana a Van Noorta [21] podobneï ukaâ zaly, zï e velikost sõâly spojenõâ vznikajõâcõâ prïi testovaâ nõâ ve smyku vykazuje vysï sï õâ hodnoty, nezï u testuê v tahu, cozï vytvaârïõâ vysï sï õâ riziko posï kozenõâ skloviny. U hodnocenõâ vyâ zkumu Valletty a Prisco [13] vykazovaly vyâsledky meïrïenõâ u pruêmeï rnyâch hodnot silu kroutõâcõâho momentu hodnoty, ktereâ majõâ statisticky vyâznamneâ rozdõâly, vysïsï õâ pro Transbond XT a mensï õâ pro Fuji GC. Bond strength of an adhesive between the bracket and enameldepends also on consistency and proportionalcomposition of an etching agent and the length of etching, on the quality of enamel surface, adhesive polymerization, distance between the source of light and a tooth. It also depends on the shape, structure, surface area and materialof the bracket base, on the oral chamber condition, and on the skills of an orthodontist [12]. In clinical practice, there are strengths arising during brackets removal, components of torsion, tension and shear [13]. The use of an optimum adhesive contributes to shorter check-ups, and thus minimizes a patient's discomfort, and eliminates the risk of brackets release [14]. Comparing methods and brackets used in different studies we conclude that the results obtained are different and very often cannot be compared, actually [15]. Eliades [16] states that the advancing speed of a testing machine over 0.5 mm/min influences the validity of results. Cagri and Irmak [17] found out that halogenous light leads to increased adhesive bond strength (mean value MPa) compared to LED light (5.83 MPa). Higher values of shear, torsion and tension tests were statistically significant in Transbond XT, lower values were statistically significant for Fuji GC. Similar results were quoted by Valetta and Prisco [13]. Our results may be different due to the structure of bracket base. Maijer and Smith [18] conclude that the results obtained for different brackets cannot be compared. The differences in measurements are also due to the fact that the bond strength of attached brackets increases during the first 24 hours - this was proved also by Wendel and Droschl [19]. In our study the measurements were done during the first hour following the bracket attachment, and consequently the values obtained were lower than those given by the authors cited above. According to Maijer and Smith the break between enameland adhesive results more from the errors occurring during the brackets attachment [20]. In fact, correct brackets attachment creates sufficient adhesion which, according to Valetta and Prisco [13], may damage enamel during the appliance removal. Enamel prism was damaged twice during shear tests in case of Spofacryl. Similarly, the results given by Regan and Van Noort [21] showed that the intensity of bond strength during shear tests is higher than in tension tests, and therefore the risk of damage to enamelis higher. According to Valetta and Prisco [13] the mean values of bond strength in torsion tests show statistically redakce@orthodont-cz.cz 21

7 rocïnõâk21 ORTODONCIE PrÏi naâ hodneâ m odlepenõâ zaâ mkuê v pruê beï hu ortodontickeâho leâcï enõâ, je cï asto klinicky zjisïteï na prïõâtomnost adheziva jen na sklovineï, co sveïdcï õâo slabeâ m spojenõâmezi baâzõâzaâ mku a adhezivem [22]. V nasïemvyâzkumu byla porovnaâvaânaveïtsï ina adheziv, ktereâ jsou na trhu dostupneâ. CõÂlem je zlepsï enõâ jejich porovnaâ vatelnosti, kdyzï byla pouzï ita jednotnaâ vyâzkumnaâ metoda. ZaÂveÏr Na zaâ kladeï provedeneâ ho vyâ zkumu pevnosti vazby v testovaâ nõâ lepenyâch spojuê mezi zaâ mkem a povrchem zubu puê sobenõâm sõâly ve smyku, tahu a krutu bylo zjisïteï no: 1. StrÏednõ hodnoty pevnosti vazby ve smyku meïl nejvysï sï õâ Transbond XT, nejnizïsï õâ zõâskalno-mix. 2. StrÏednõ hodnoty pevnosti vazby v tahu meï lnejvysïsï õâ Medicept Light Cure, nejnizïsï õâ zõâskaltetric flow. 3. StrÏednõ hodnoty pevnosti vazby ve krutu meï lnejvysï sï õâ Light Bond Reliance, nejnizïsï õâ zõâskalgranitec Falcon. 4. Hodnoty ukazatele ARI se v testech prïevaâzïneï ukazovaly na 2. stupni. Vy jimkou byla pryskyrïice Spofacryl, Light Bond a Medicept Light Cure u kteryâchprïevazï oval1. stupenï. AutorÏi nemajõâ komercï nõâ, vlastnickeâ nebo financï nõâ zaâ jmy na produktech nebo spolecï nostech popsanyâ ch v tomto cïlaâ nku. significant differences - they are higher in Transbond XT, and lower in case of Fuji GC. In randomly detached brackets during the orthodontic treatment, clinical examination often finds adhesive remnants only on the enamel which is the evidence of weak attachment between the bracket base and and adhesive [22]. In our study most adhesives available on the market were compared. The aim is to improve comparative methods for the assessment of their quality. Conclusion Based on the results of the analysis of the adhesive bond strength examined by shear, tension and torsion tests, we obtained the following results: 1. The highest mean values of bond strength in shear test were recorded for Transbond XT, the lowest for No-Mix. 2. The highest mean values of bond strength in tension tests were recorded for Medicept Light Cure, the lowest for Tetric flow. 3. The highest mean values of bond strength in torsion tests were recorded for Light Bond Reliance, the lowest for Granitec Falcon. 4. ARI values were mostly on degree 2. In Spofacryl, Light Bond and Medicept Light Cure resins ARI values were mostly on degree 1. Authors have no commercial, proprietary or financial interest in products or companies mentioned in the article. Literatura/References 1. Newman G. V.: Adhesion and orthodontic plastic attachments. Amer. J. Orthodont. dentofacialorthop. 1969, 56, cï. 6, s Reynolds I. R.; von Fraunhofer J. A.: Direct bonding of orthodontic attachments to teeth: the relation of adhesive bond strength to gauze mesh size. Brit. J. Orthodont. 1976, 3, cï. 2, s Kao E. C.; Eliades T.; Rezvan E.; Johnston W. M.: Torsionalbond strength and failure pattern of ceramic brackets bonded to composite resin laminate veneers. Eur. J. Orthodont. 1995, 17, cï. 6, s Relief, D.H.: Failure AT the dental adhesive etched enamelinterface: J. OralRehab. 1974, 1, cï. 3, s Bishara, S.E.; Fehr, D.: Comparisons of the effectiveness of pliers with narrow and wide blades in debonding ceramic brackets. Amer. J. Orthodont. dentofacialorthop. 1993, 3, cï. 3, s Nkenke N.; Hirsfelder U.; Martus P.: Evaluation of the bond strength of different bracket-bonding systems to bovine enamel. Eur. J. Orthodont. 1997, 19, cï. 3, s Reynolds I. R.: A review of direct orthodontic bonding. Brit. J. Orthodont. 1975, cï. 2, s Kallio T. T.; LastumaÈ ki T. M.; Vallittu P. K.: Bonding of restorative and veneering composite resin to some polymeric composites. Dent. Mater. 2001, 17, cï. 1, s Nosowicz P.; Czarnecka B.: Clinical aspects of bonding orthodontic brackets to various dentalrestorative materials. Czas. Stomatol. 2006, 59, cï. 4, s Artun J.; Bergland S.; Clinical trials with crystal growth conditioning as an alternative to acid-etch enamel pretreatment. Amer. J. Orthodont. 1984, 85, cï. 4, s Proffit W.R.,; Fields H.W.: Ortodoncja wspoâ cç zesna. Czelej Publishing House Bishara S. E.; Ostby A. W.; Laffoon J. F.; Warren J.: Shear Bond Strength, Bond comparison of two adhesive systems following thermocycling. A new self-etch primer and a resin-modified glass ionomer. Angle Orthodont. 2007, 77, cï. 2, s Valletta R.; Prisco.D.; Ambrosio L.: Evaluation of the debonding strength of orthodontic brackets using three different bonding systems. Eur. J. Orthodont., 2007, 29, cï. 6, s Graber T. M.; Vanarsdall Jr. R. L. Orthodontics, current principles and techniques. 3rd end. Mosby, St Louis redakce@orthodont-cz.cz

8 ORTODONCIE rocïnõâk Prietsch J.R. et al: Development of a device to measure bracket debonding force in vivo. Eur. J. Orthodont. 2007, 29, cï. 6, s Eliades T.; Brantley W.A.: The inappropriateness of conventionalorthodontic Bond strength assessment protocols. Eur. J. Orthodont. 2000, 22, cï. 1, s Cagri U.; Ozgur I.: Temperature rise and shear bond strength of bondable buccal tubes bonded by various light sources. Eur. J. Orthodont. 2000, 30, cï. 4, s Smith D. C.; Maijer R.: Improvements in bracket base design. Amer. J. Orthodont. 1983, 83, cï. 4, s WendlB.; DroschlH.: A comparative in vitro study of the strength of directly bonded brackets using different curing techniques. Eur. J. Orthodont. 2004, 26, cï 5, s Maijer R.; Smith D.C.: Variables influencing the bond strength of metalorthodontic bracket bases. Amer. J. Orthodont. 1981, 79, cï. 1, s Regan D.; Van Noort R.: Bond strengths of two integral bracket base combinations: an in vitro comparison with foil-mesh. Eur. J. Orthodont. 1989, 11, cï. 2, s Lopez J.: Retentive shear strengths of various bonding attachment bases. Amer. J. Orthodont. 1980, 77, cï. 6, s Bartøomiej Pawlus Klinika zubnõâho leâ karïstvõâ Palacke ho 12, Olomouc KolegoveÂ, vyuzï ijte mozï nosti doprovodneâ ho programu Kongresu CÏ OS pro rodinneâ prïõâslusï nõâky v laâ znõâch LuhacÏ ovice. PodeÏ kovaâ nõâ Ra di bychom podeï kovali koleguê m MUDr. Tvardkovi a MUDr. Suche mu za vynikajõâcõâ ortodontickeâ seminaârïe, ktereâ probeï hly v lednu a v uâ noru letosï nõâho roku na Stomatologicke klinice 3. LF UK v Praze v raâ mci seminaârïuê postgraduaâ lnõâho studia oboru ortodoncie. MUDr. Tvradek s prïehledem a velmi srozumitelneï prïednaâ sï elo biomechanice a MUDr. Suchy naâ s seznaâ mils vyâ sledky terapie a s uâ skalõâmi praâ ce se samoligovacõâmi zaâ mky. MUDr. M. Kot'ovaÂ, Ph.D. redakce@orthodont-cz.cz 23