SURFACE CHANGES OF ENAMEL AND DENTIN AFTER TWO DIFFERENT BLEAC HING PROC EDURES

Sredstva za izbjeljivanje zubi mogu utjecati na kemijska i fizička svojstva, kao i na mikromorfološku strukturu cakline i dentina, na što se mora pripaziti prilikom provođenja ovakve terapije. Svrha ovoga istraživanja je bila procijeniti učinak dvaju sredstava za izbjeljivanje koja sadrže visoke koncentracije vodikovog peroksida na površinu cakline i dentina, kao i potencijalni remineralizacijski učinak gela amorfnog kalcijevog fosfata (ACP). Dvadesetpet ljudskih trećih molara podijeljeno je u dvije skupine, raspiljeno napola i obje površine su zatim tretirane gelom ZOOM2 ili Opalescence BOOST u trajanju od 3×15 minuta. Vickersova mikrotvrdoća cakline i dentina izmjerena je neposredno prije, nakon postupka izbjeljivanja i nakon tretmana umjetnom slinom i gelom ACP-a kroz 2 tjedna ili nakon držanja u deioniziranoj vodi kroz isto razdoblje. Površinske promjene su promatrane SEM mikroskopom. Korišteni su Mješovoti ANOVA model i Wilcoxon Rank Sum test. Oba gela za izbjeljivanje pokazala su značajno smanjenje u površinskoj mikrotvrdoći cakline i dentina (p<0,001 za BOOST i ZOOM2). ZOOM2 koji je imao nižu pH vrijednost je pokazao veće smanjenje površinske mikrotvrdoće (p=0,005) u odnosu na BOOST. Naknadna obrada umjetnom slinom i pripravkom ACP-a pokazla je značajno povećanje površinske mikrotvrdoće (p<0,001). Nakon izbjeljivanja površine cakline i dentina su pokazale blage ili umjerene promjene bez gubitka površinske strukture. Zaključno, oba sredstva za izbjeljivanje dovela su do smanjenja površinske mikrotvrdoće. Tretman ACP-om nakon izbjeljivanja doveo je do povišenja mikrotvrdoće i smanjio površinska oštećenja poboljšavši remineralizaciju tvrdih zubnih tkiva.Bleaching agents have effect on chemical / physical and morphological structure of enamel and dentine that must be taken into account when this therapy is used. The aim of this in vitro study was to evaluate the effects of two bleaching agents containing high concentration of hydrogen peroxide for professional use on human enamel and dentine surface and to evaluate the potential remineralizing effect of amorphous calcium phosphate gel (ACP). Twenty five human third molars were divided into two groups and disected in half and both surfaces were bleached with either ZOOM2 or Opalesence BOOST for 3×15 minutes. Vickers microhardness of enamel and dentine was measured before, after the bleaching treatment and after treatment with artificial saliva and ACP gel or 2 weeks storage in deionized water. Surface microstructure was evaluated using SEM. Mixed model ANOVA and Wilcoxon Rank Sum test were used. Both bleaching agents showed significant reduction in surface microhardness (p<0.001 for both BOOST and ZOOM2 application). ZOOM2 which had the lower pH value showed larger decrease in surface microhardness (p=0.005) compared to BOOST. Post-treatment with artificial saliva and ACP showed significant increase in surface microhardness (p<0.001). After the bleaching procedure enamel and dentine surface microstructure showed mild or slight alterations with no loss of superficial structure. Both bleaching agents resulted in a reduction in surface enamel and dentine microhardness. Treatment with ACP demonstrated the increase in surface microhardness, improved surface roughnes and enhance the remineralization of the hard dental tissues

Effect of new light sources for teeth bleaching

Izbjeljivanje zubi je postupak kojim se tretiraju te u odreĊenom stupnju otklanjaju razliĉite diskoloracije zubi. Aktivni spoj svih sredstava za izbjeljivanje je vodikov peroksid. Mehanizam reakcije vodikovog peroksida nije u potpunosti razjašnjen, ali se smatra da je proces oksidacije, gdje se velike pigmentirane molekule razlažu u manje, odgovoran za izbjeljivanje. Izvori svjetlosti mogu poboljšati izbjeljivanje tako što fotokatalitiĉki ili termokatalitiĉki ubrzavaju aktivni raspad molekula vodikovog peroksida. U ovome istraživanju ispitivao se uĉinak novih izvora svjetlosti: LED405, OLED i femtosekundnog lasera, a kao kontrolni izvor svjetlosti koristio se ZOOM2. Od komercijalnih sredstva za izbjeljivanje koristili su se 10%, 16% i 30% gel karbamid peroksida te 25% i 38% gel vodikovog peroksida. Povišenje temperature pulpne komore iznad kritiĉne vrijednost od 5.5 C zabilježeno je prilikom korištenja fokusiranog femtosekundnog lasera i ZOOM2 izvora svjetlosti, dok nefokusirani femtosekundni laser, LED405 i OLED nisu pokazali znaĉajan porast temperature u pulpnoj komori i na površini. Aktivacija gelova za izbjeljivanje ranije navedenim izvorima svjetlosti nije pokazala veća oštećenja površine cakline i dentina, kao i pojaĉano smanjenje mikrotvrdoće, nego kada su se koristili smo gelovi za izbjeljivanje bez svjetlosne aktivacije. U kemijskom sastavu cakline i dentina nakon izbjeljivanja takoĊer su zabilježene promjene u kvantitativnom omjeru elemenata specifiĉnih za ova tvrda zubna tkiva dok su se preparatima amorfnog kalcijevog fosfata ili boravkom u umjetnom slini sve ranije navedene strukturne, kemijske i morfološke promjene vratile na približno poĉetne vrijednosti, odnosno došlo je i do znaĉajnog porasta odreĊenih kemijskih elemenata odgovornim za remineralizaciju i potencijalni karijesprotektivni uĉinak (Ca, F). Novi izvori svjetlosti LED405 i femtosekundni laser, u kombinaciji s gelovima za izbjeljivanje, doveli su do znaĉajnog poboljšanja u promjeni boje obojanih pastila hidroksilapatita u odnosu na OLED i mjerenja pri kojima smo koristili samo gelove bez svjetlosne aktivacije. Zakljuĉno, sredstava za izbjeljivanje, korištena u kontroliranim kliniĉkim uvjetima pokazala su potencijalni genotoksiĉni i karcinogeni uĉinak na stanice oralne sluznice. Genom stanica pri tome je narušen, ali ne do vrijednosti koja bi bila kliniĉki znaĉajna.The purpose Tooth whitening is becoming one of the most popular esthetic and corrective treatments for discolored teeth. Bleaching can be performed internally on non-vital teeth or externally on vital teeth by applying hydrogen peroxide, sodium perborate or carbamide peroxide, the most common agents used for bleaching. For acceleration or more effective tooth whitening, different light sources may be used. When the bleaching agent is activated under the influence of light, some amount of light is absorbed and the resulting energy is converted into heat. This can be perceived as a possible side effect during this type of tooth whitening. Therefore, light sources can have photothermal effects which are then associated with the chemical effect of the bleaching materials. In light-activated tooth bleaching procedures, there is a great concern about the heat generated by the light source, which may cause pulp irritation or severe damage such as necrosis. One of the purposes of the present study was to evaluate the surface and intrapulpal temperature changes after bleaching treatment with different gels of hydrogen peroxide (in further text HP) and carbamide peroxide (in further text CP) subjected to different sources of light activation (LED405, OLED, focused and unfocused femtosecond laser and ZOOM2). Also, one of the aims was to evaluate the influence of five bleaching agents on surface microstructure, change in chemical structure and microhardness of human tooth enamel and dentine as well as the change in color of stained specimens before and after the bleaching with different bleaching agents supported by new light sources. Finally, a possible genotoxic effect of two bleaching gels with high concentration of hydrogen peroxide on oral mucosa was investigated. Materials and methods Light sources used in this study were: LED405, OLED, femtosecond laser and ZOOM2. Each experimental group was treated with one of the following: 25% and 38% HP gel and 10%, 16% and 30% CP bleaching gels. For intrapulpal and surface temperature measurements, K-type thermocouple and infrared thermometer were used to repeatedly measure the temperature increase. Tooth surface was treated with five bleaching agents and vaseline which served as a control. For temperature measurements, we used extracted human maxillary central incisors and canines. Vickers microhardness was measured with a load of 100 g for 10 seconds at the baseline, after the last bleaching treatment and after 2 weeks storage in artificial saliva and surface treatment with amorphous calcium phosphate gel (in further text ACP) or 2 weeks storage in deionized water. Enamel and dentine surface morphology was observed under scanning electron microscopy (SEM) while structural and chemical changes were evaluated using energy-dispersive X-ray spectroscopy (EDS). For microhardness as well as SEM and EDS measurements, extracted human third molars were used. Change in color was determined by RGB colorimeter and UV VIS NIS spectrophotometer. For color measurement, specially made pastilles of hydroxyapatite were used. Genotoxic effect of two bleaching agents was analyzed using micronucleus test and the research was conducted on 22 human subjects. Results The average increases in the pulp chamber and tooth surface temperatures for LED405, OLED and unfocused femtosecond laser were below the critical temperature threshold of 5.5C, contrary to the treatments involving ZOOM2 and focused femtosecond laser, regardless of bleaching gel application. All bleaching agents showed significant reduction in surface microhardness. ZOOM2, which had the lower pH value (pH=3.20), showed larger decrease in surface microhardness compared to BOOST (pH=6.75) and 30 %, 16% and 10 % CP (pH=7.0). The treatment with ACP and artificial saliva can increase microhardness and reduce the mineral loss after bleaching treatment. After the bleaching procedure with highly concentrated HP and CP gels, enamel and dentine surface microstructure showed mild or slight alterations with no loss of superficial structure, while low concentration CP gels show no change in morphological structure of tested hard dental tissue. A statistically significant increase in Ca and F ions was found after the bleaching treatment and after the additional treatment with ACP and artificial saliva. The change in color before and after the whitening treatment with different light sources was measured using RGB and UV VIS NIR spectral analysis. After 30 minutes of bleaching treatment with LED405, there was a statistically significant increase in RGB index in comparison to OLED and without light activation for 10% CP, 16% CP, 30% CP, 25 % HP and 38 % HP gels. For femtosecond laser, a statistically significant increase in RGB index was found only when 16 % CP and 38 % HP were used. Finally, the difference between LED405 and femtosecond laser was statistically significant only when 25 % HP gel was used. Both of the tested bleaching agents (25% HP and 38 % HP) demonstrated a potential genotoxic effect. Statistically significant increase of genotoxicity markers was relatively small in amount. Significance Focused femtosecond laser and ZOOM2 produced a large temperature increase in the pulp chamber and at the tooth surface. Caution is advised when using these types of light activation, whereas LED405, OLED and unfocused femtosecond laser could be safely used. Although the application of the bleaching agents reduced temperature variability, the type of the bleaching agent applied was largely irrelevant, indicating similar insulating properties of different gels of HP and CP. All of the used bleaching agents resulted in a reduction of surface enamel and dentine microhardness. The application of ACP remineralizing agents in combination with artificial saliva can cause an increase in surface microhardness. A change in chemical structure of enamel and dentine after bleaching with different bleaching gels and after ACP treatment was found for Ca and F ions which can be a sign of possible remineralization. In combination with the used bleaching agents, LED 405 showed the best effect in color change, followed by femtosecond laser. OLED light showed the weakest effect in color change. Regarding the genotoxic effect of bleaching agents used in this study, it is important to say that oral mucosa cells have a short lifespan and a one-time exposure to such mild genotoxic noxa has probably a negligible carcinogenic potential. Therefore, bleaching can affect the genome of mucosal cells to a certain extent; however, it is difficult to assess clinical significance of these findings

Effect of new light sources for teeth bleaching

Izbjeljivanje zubi je postupak kojim se tretiraju te u odreĊenom stupnju otklanjaju razliĉite diskoloracije zubi. Aktivni spoj svih sredstava za izbjeljivanje je vodikov peroksid. Mehanizam reakcije vodikovog peroksida nije u potpunosti razjašnjen, ali se smatra da je proces oksidacije, gdje se velike pigmentirane molekule razlažu u manje, odgovoran za izbjeljivanje. Izvori svjetlosti mogu poboljšati izbjeljivanje tako što fotokatalitiĉki ili termokatalitiĉki ubrzavaju aktivni raspad molekula vodikovog peroksida. U ovome istraživanju ispitivao se uĉinak novih izvora svjetlosti: LED405, OLED i femtosekundnog lasera, a kao kontrolni izvor svjetlosti koristio se ZOOM2. Od komercijalnih sredstva za izbjeljivanje koristili su se 10%, 16% i 30% gel karbamid peroksida te 25% i 38% gel vodikovog peroksida. Povišenje temperature pulpne komore iznad kritiĉne vrijednost od 5.5 C zabilježeno je prilikom korištenja fokusiranog femtosekundnog lasera i ZOOM2 izvora svjetlosti, dok nefokusirani femtosekundni laser, LED405 i OLED nisu pokazali znaĉajan porast temperature u pulpnoj komori i na površini. Aktivacija gelova za izbjeljivanje ranije navedenim izvorima svjetlosti nije pokazala veća oštećenja površine cakline i dentina, kao i pojaĉano smanjenje mikrotvrdoće, nego kada su se koristili smo gelovi za izbjeljivanje bez svjetlosne aktivacije. U kemijskom sastavu cakline i dentina nakon izbjeljivanja takoĊer su zabilježene promjene u kvantitativnom omjeru elemenata specifiĉnih za ova tvrda zubna tkiva dok su se preparatima amorfnog kalcijevog fosfata ili boravkom u umjetnom slini sve ranije navedene strukturne, kemijske i morfološke promjene vratile na približno poĉetne vrijednosti, odnosno došlo je i do znaĉajnog porasta odreĊenih kemijskih elemenata odgovornim za remineralizaciju i potencijalni karijesprotektivni uĉinak (Ca, F). Novi izvori svjetlosti LED405 i femtosekundni laser, u kombinaciji s gelovima za izbjeljivanje, doveli su do znaĉajnog poboljšanja u promjeni boje obojanih pastila hidroksilapatita u odnosu na OLED i mjerenja pri kojima smo koristili samo gelove bez svjetlosne aktivacije. Zakljuĉno, sredstava za izbjeljivanje, korištena u kontroliranim kliniĉkim uvjetima pokazala su potencijalni genotoksiĉni i karcinogeni uĉinak na stanice oralne sluznice. Genom stanica pri tome je narušen, ali ne do vrijednosti koja bi bila kliniĉki znaĉajna.The purpose Tooth whitening is becoming one of the most popular esthetic and corrective treatments for discolored teeth. Bleaching can be performed internally on non-vital teeth or externally on vital teeth by applying hydrogen peroxide, sodium perborate or carbamide peroxide, the most common agents used for bleaching. For acceleration or more effective tooth whitening, different light sources may be used. When the bleaching agent is activated under the influence of light, some amount of light is absorbed and the resulting energy is converted into heat. This can be perceived as a possible side effect during this type of tooth whitening. Therefore, light sources can have photothermal effects which are then associated with the chemical effect of the bleaching materials. In light-activated tooth bleaching procedures, there is a great concern about the heat generated by the light source, which may cause pulp irritation or severe damage such as necrosis. One of the purposes of the present study was to evaluate the surface and intrapulpal temperature changes after bleaching treatment with different gels of hydrogen peroxide (in further text HP) and carbamide peroxide (in further text CP) subjected to different sources of light activation (LED405, OLED, focused and unfocused femtosecond laser and ZOOM2). Also, one of the aims was to evaluate the influence of five bleaching agents on surface microstructure, change in chemical structure and microhardness of human tooth enamel and dentine as well as the change in color of stained specimens before and after the bleaching with different bleaching agents supported by new light sources. Finally, a possible genotoxic effect of two bleaching gels with high concentration of hydrogen peroxide on oral mucosa was investigated. Materials and methods Light sources used in this study were: LED405, OLED, femtosecond laser and ZOOM2. Each experimental group was treated with one of the following: 25% and 38% HP gel and 10%, 16% and 30% CP bleaching gels. For intrapulpal and surface temperature measurements, K-type thermocouple and infrared thermometer were used to repeatedly measure the temperature increase. Tooth surface was treated with five bleaching agents and vaseline which served as a control. For temperature measurements, we used extracted human maxillary central incisors and canines. Vickers microhardness was measured with a load of 100 g for 10 seconds at the baseline, after the last bleaching treatment and after 2 weeks storage in artificial saliva and surface treatment with amorphous calcium phosphate gel (in further text ACP) or 2 weeks storage in deionized water. Enamel and dentine surface morphology was observed under scanning electron microscopy (SEM) while structural and chemical changes were evaluated using energy-dispersive X-ray spectroscopy (EDS). For microhardness as well as SEM and EDS measurements, extracted human third molars were used. Change in color was determined by RGB colorimeter and UV VIS NIS spectrophotometer. For color measurement, specially made pastilles of hydroxyapatite were used. Genotoxic effect of two bleaching agents was analyzed using micronucleus test and the research was conducted on 22 human subjects. Results The average increases in the pulp chamber and tooth surface temperatures for LED405, OLED and unfocused femtosecond laser were below the critical temperature threshold of 5.5C, contrary to the treatments involving ZOOM2 and focused femtosecond laser, regardless of bleaching gel application. All bleaching agents showed significant reduction in surface microhardness. ZOOM2, which had the lower pH value (pH=3.20), showed larger decrease in surface microhardness compared to BOOST (pH=6.75) and 30 %, 16% and 10 % CP (pH=7.0). The treatment with ACP and artificial saliva can increase microhardness and reduce the mineral loss after bleaching treatment. After the bleaching procedure with highly concentrated HP and CP gels, enamel and dentine surface microstructure showed mild or slight alterations with no loss of superficial structure, while low concentration CP gels show no change in morphological structure of tested hard dental tissue. A statistically significant increase in Ca and F ions was found after the bleaching treatment and after the additional treatment with ACP and artificial saliva. The change in color before and after the whitening treatment with different light sources was measured using RGB and UV VIS NIR spectral analysis. After 30 minutes of bleaching treatment with LED405, there was a statistically significant increase in RGB index in comparison to OLED and without light activation for 10% CP, 16% CP, 30% CP, 25 % HP and 38 % HP gels. For femtosecond laser, a statistically significant increase in RGB index was found only when 16 % CP and 38 % HP were used. Finally, the difference between LED405 and femtosecond laser was statistically significant only when 25 % HP gel was used. Both of the tested bleaching agents (25% HP and 38 % HP) demonstrated a potential genotoxic effect. Statistically significant increase of genotoxicity markers was relatively small in amount. Significance Focused femtosecond laser and ZOOM2 produced a large temperature increase in the pulp chamber and at the tooth surface. Caution is advised when using these types of light activation, whereas LED405, OLED and unfocused femtosecond laser could be safely used. Although the application of the bleaching agents reduced temperature variability, the type of the bleaching agent applied was largely irrelevant, indicating similar insulating properties of different gels of HP and CP. All of the used bleaching agents resulted in a reduction of surface enamel and dentine microhardness. The application of ACP remineralizing agents in combination with artificial saliva can cause an increase in surface microhardness. A change in chemical structure of enamel and dentine after bleaching with different bleaching gels and after ACP treatment was found for Ca and F ions which can be a sign of possible remineralization. In combination with the used bleaching agents, LED 405 showed the best effect in color change, followed by femtosecond laser. OLED light showed the weakest effect in color change. Regarding the genotoxic effect of bleaching agents used in this study, it is important to say that oral mucosa cells have a short lifespan and a one-time exposure to such mild genotoxic noxa has probably a negligible carcinogenic potential. Therefore, bleaching can affect the genome of mucosal cells to a certain extent; however, it is difficult to assess clinical significance of these findings

Snaga svezivanja na dentin i pouzdanost eksperimentalnih bioaktivnih kompozita

Weibull analysis of bond strength Aim: To compare differences in outcomes of statistical approaches of reliability analysis (Weibull) and conventional statistics for bond strength of experimental remineralizing composites and disclose changes that would not be discernible by using just one statistical approach. Materials and Methods: Experimental composites were made by blending a Bis-GMA/TEGDMA resin with bioactive glass (BG) and inert fillers (barium glass and silica) in a centrifugal mixer. Inert fillers were admixed to the total filler load of 70 wt%. Control composite incorporated only inert fillers (70 wt%). Two remineralizing composites with 10 or 40 wt% of BG were marked as bioactive-10 and bioactive-40. Dentin substrates were prepared from intact third molars, polished under the water using P600 silicon carbide paper and embedded into an acrylic resin. Composite cylinders (d=3mm, h=2mm) were bonded on dentin substrates using a two-step self-etch bonding agent (Clearfil SE Bond 2, Kur- aray). Specimens were stored at 37 °C in distilled water and fractured in shear mode after 1 week and 1 year. Per experimental group 20 samples were prepared in order to obtain the optimal sample size for Weibull analysis (total n=120 for the whole study). Results: Mean bond strengths measured after 1 week and 1 year were statistically similar for the control composite (21.9 vs. 24.0 MPa) and for bioactive-10 (19.6 vs. 19.1 MPa). Nevertheless, Weibull statistics identified a significant decrease in bond reliability after aging: Weibull moduli were decreased from 13.5 to 3.9 for the control composite and from 12.3 to 3.8 for bioactive-10. For bioactive-40, mean bond strength declined significantly after 1 year (8.1 vs. 6.8 MPa) but its reliability remained unchanged, as identified by statistically similar Weibull moduli. Conclusions: A decrease in dentin bond strength after 1 year was identified using Weibull analysis in the control and experimental bioactive composite, while conventional statistics were incapable to distin- guish changes in mean bond strength.Cilj: Usporediti razlike u rezultatima snage svezivanja eksperimentalnih remineralizacijskih kompozita dobivenih statističkim pristupom analize pouzdanosti (Weibull) i konvencionalne statistike te otkriti promjene koje nisu vidljive korištenjem samo jednog statističkog pristupa. Materijali i metode: Eksperimentalni kompoziti dobiveni su miješanjem smole Bis-GMA / TEGDMA s bioaktivnim staklom (BG) i inertnim punilima (barijevo staklo i silicijev dioksid) u centrifugalnoj miješalici. Inertna punila dodana su do ukupnog opterećenja punila od 70%. Kontrolni kompozit sadrži samo inertna punila (70%). Dva remineralizirajuća kompozita s masenim udjelom bioaktivnog stakla (BG) 10% ili 40% označena su kao bioaktivni-10 i bioaktivni-40. Dentinski supstrati pripremljeni su od intaktnih trećih kutnjaka, polirani pomoću papira silicijevog karbida P600 i ugrađeni u akrilatnu smolu. Adhezijska veza između kompozitnih cilindara (širina = 3 mm, visina = 2 mm) i dentina stvorena je pomoću dvokomponentnog samojetkajućeg adheziva (Clearfil SE Bond 2, Kuraray). Uzorci su sk- ladišteni na 37 ° C u destiliranoj vodi i testirani u uređaju za mjerenje jačine adhezijske sveze (test smi- canja) nakon 1 tjedna i 1 godine. Optimalni broj uzoraka za analizu pouzdanosti dobiven je pripremom n=20 po eksperimentalnoj skupini (ukupno n=120 za cijelo istraživanje). Rezultati: Srednja snaga svezivanja mjerena nakon 1 tjedna i 1 godine bila je statistički slična za kon- trolni kompozit (21,9 naspram 24,0 MPa) i za bioaktivni-10 (19,6 naspram 19,1 MPa). Međutim, Weibullova statistika otkrila je značajan pad pouzdanosti veze nakon starenja: Weibullovi moduli sman- jili su se sa 13,5 na 3,9 za kontrolni kompozit i sa 12,3 na 3,8 za bioaktivni-10. Za bioaktivni-40, pros- ječna čvrstoća veze značajno je pala nakon jedne godine (8,1 prema 6,8 MPa), ali njegova pouzdanost je ostala nepromijenjena, što je utvrđeno statistički sličnim Weibullovim modulima. Zaključak: Pogoršanje snage svezivanja nakon jedne godine utvrđeno je korištenjem analize pouzdanosti kod kontrolnog i eksperimentalnog bioaktivnog kompozita iako konvencionalna statistika nije mogla razlikovati promjene prosječne snage svezivanja

Mikrotvrdoća bulk-fill kompozitnih smola

The aim of the study was to determine microhardness of high- and low-viscosity bulk-fill composite resins and compare it with conventional composite materials. Four materials of high-viscosity were tested, including three bulk-fills: QuiXfi l (QF), x-tra fil (XTF) and Tetric EvoCeram Bulk Fill (TEBCF), while nanohybrid composite GrandioSO (GSO) served as control. The other four were low-viscosity composites, three bulk-fill materials: Smart Dentin Replacement (SDR), Venus Bulk Fill (VBF) and x-tra base (XB), and conventional control material X-Flow (XF). Composite samples (n=5) were polymerized for 20 s with Bluephase G2 curing unit. Vickers hardness was used to determine microhardness of each material at the surface, and at 2-mm and 4-mm depth. GSO on average recorded significantly higher microhardness values than bulk-fill materials (p<0.001). The low-viscosity composite XF revealed similar microhardness values as SDR, but signifi cantly lower than XB (p<0.001) and significantly higher than VBF (p<0.001). Microhardness of high-viscosity bulk-fill materials was lower than microhardness of the conventional composite material (GSO). Surface microhardness of low-viscosity materials was generally even lower. The microhardness of all tested materials at 4 mm was not different from their surface values. However, additional capping layer was a necessity for low-viscosity bulk-fill materials due to their low microhardness.Svrha istraživanja bila je odrediti mikrotvrdoću visoko-viskoznih i nisko-viskoznih bulk-fill kompozitnih smola i usporediti ih s konvencionalnim kompozitnim materijalima. Četiri visoko-viskozna materijala su testirana, od toga tri bulk-fill: QuiXfi l (QF), x-tra fil (XTF) i Tetric EvoCeram Bulk Fill (TEBCF); nanohibridni kompozit GrandioSO (GSO) služio je kao kontrola. Ostala četiri materijala bila su nisko-viskozna, tri bulk-fill: Smart Dentin Replacement (SDR), Venus Bulk Fill (VBF) i x-tra base (XB) te konvencionalni kontrolni materijal X-Flow (XF). Kompozitni uzorci (n=5) polimerizirani su 20 s polimerizacijskom lampom Bluephase G2. Mikrotvrdoća svakog materijala na površini te na dubini od 2 i 4 mm je određena po Vickersu. GSO je u prosjeku imao značajno više vrijednosti mikrotvrdoće od ostalih materijala (p<0,001). Niskoviskozni kontrolni kompozit XF imao je slične vrijednosti kao SDR, ali značajno niže nego nego XB (p<0,001) i značajno više nego VBF (p<0,001). Mikrotvrdoća visoko-viskoznih bulk-fill materijala je niža nego kod konvencionalnog kompozitnog materijala GSO. Površinska mikrotvrdoća nisko-viskoznih materijala je općenito još niža. Mikrotvrdoća svih testiranih materijala na dubini od 4 mm se ne razlikuje od njihovih površinskih vrijednosti mikrotvrdoće. Dodatni sloj kompozita za prekrivanje nisko-viskoznih bulk-fill materijala je nužan zbog njihove male mikrotvrdoće

Promjene na površini cakline i dentina nakon dva različita postupka izbjeljivanja

Bleaching agents have effect on chemical/physical and morphological structure of enamel and dentin that must be taken into account when this therapy is used. The aim of this in vitro study was to evaluate the effects of two bleaching agents containing a high concentration of hydrogen peroxide for professional use on human enamel and dentin surface and to evaluate the potential remineralizing effect of amorphous calcium phosphate gel (ACP). Twenty-five human third molars were divided into two groups and dissected in half and both surfaces were bleached with either ZOOM2 or Opalescence BOOST for 3×15 minutes. Vickers microhardness of enamel and dentin was measured before, after the bleaching treatment, and after treatment with artificial saliva and ACP gel or 2-week storage in deionized water. Surface microstructure was evaluated using scanning electron microscopy. The mixed model ANOVA and Wilcoxon Rank Sum test were used. Both bleaching agents showed significant reduction in surface microhardness (p<0.001 for both BOOST and ZOOM2 application). ZOOM2, which had a lower pH value showed greater decrease in surface microhardness (p=0.005) compared to BOOST. Post-treatment with artificial saliva and ACP showed significant increase in surface microhardness (p<0.001). After the bleaching procedure, enamel and dentin surface microstructure showed mild or slight alterations with no loss of superficial structure. In conclusion, both bleaching agents resulted in reduction in surface enamel and dentin microhardness. Treatment with ACP led to increase in surface microhardness, improved surface roughness, and enhanced remineralization of the hard dental tissues.Sredstva za izbjeljivanje zubi mogu utjecati na kemijska i fizička svojstva, kao i na mikromorfološku strukturu cakline i dentina, na što se mora pripaziti prilikom provođenja ovakve terapije. Svrha ovoga istraživanja je bila procijeniti učinak dvaju sredstava za izbjeljivanje koja sadrže visoke koncentracije vodikovog peroksida na površinu cakline i dentina, kao i potencijalni remineralizacijski učinak gela amorfnog kalcijevog fosfata (ACP). Dvadesetpet ljudskih trećih molara podijeljeno je u dvije skupine, raspiljeno napola i obje površine su zatim tretirane gelom ZOOM2 ili Opalescence BOOST u trajanju od 3×15 minuta. Vickersova mikrotvrdoća cakline i dentina izmjerena je neposredno prije, nakon postupka izbjeljivanja i nakon tretmana umjetnom slinom i gelom ACP-a kroz 2 tjedna ili nakon držanja u deioniziranoj vodi kroz isto razdoblje. Površinske promjene su promatrane SEM mikroskopom. Korišteni su Mixed model ANOVA i Wilcoxon Rank Sum test. Oba gela za izbjeljivanje pokazala su značajno smanjenje u površinskoj mikrotvrdoći cakline i dentina (p<0,001 za BOOST i ZOOM2). ZOOM2 koji je imao nižu pH vrijednost je pokazao veće smanjenje površinske mikrotvrdoće (p=0,005) u odnosu na BOOST. Naknadna obrada umjetnom slinom i pripravkom ACP-a pokazla je značajno povećanje površinske mikrotvrdoće (p<0,001). Nakon izbjeljivanja površine cakline i dentina su pokazale blage ili umjerene promjene bez gubitka površinske strukture. U zaključku, oba sredstva za izbjeljivanje dovela su do smanjenja površinske mikrotvrdoće. Tretman ACP-om nakon izbjeljivanja doveo je do povišenja mikrotvrdoće i smanjio površinska oštećenja poboljšavši remineralizaciju tvrdih zubnih tkiva

Rizični čimbenici povezani s nastankom crnih obojenja na zubima

The aim of the study was to show whether there is any influence of food, drink or drug intake on the formation of tooth discoloration. A total of 500 patients aged 15-25 years were examined to take part in the study. Of these, 60 patients were selected and divided into two groups of 30 patients each. Group 1 included patients with blackpigmentation on vestibular/oral tooth surfaces. Group 2 included patients without discoloration (control). Data were recorded in a questionnaire. Atomic absorption spectrometry was used to determine elements in discoloration samples. The Caries Risk Test (CRT) buffer was used to assess buffer capacity of saliva, while CRT bacteria were used to determine the presence of Streptococcus mutans and Lactobacillusspp. Statistically significant betweengroup differences were found for the intake of collard greens and beets (p<0.05), but not for other vegetables. As for drink consumption, patients with pigmentation reported less wine intake (p<0.05) than those without pigmentation. There was no diff erence according to drug intake between patients with and without pigmentation. Patients with pigmentation were older, smoked and had lower saliva pH with lower presence of Streptococcus mutansthan those without pigmentation (p<0.05). In tooth discoloration samples, there were traces of calcium, magnesium, iron, copper and zinc. The appearance of tooth discoloration is influenced by many factors, among which diet and saliva seem to be very important. Our study showed that patients with black pigmentation used to take more beets, while patients without pigmentation were taking more collard greens and red wine.Svrha ovoga istraživanja bila je dokazati postoji li utjecaj konzumacije hrane, pića ili lijekova na nastanak i pojavnost crnihobojenja na zubima. Ukupno 500 pacijenata u dobi od 15-25 godina pregledano je i uključeno u ovu studiju. Od ukupnog broja, 60 pacijenata je odabrano i podijeljeno u dvije skupine od 30 pacijenata. Skupina 1. je uključivala pacijente s crnim obojenjima na vestibularnim/oralnim plohama zuba. Skupina 2. je uključivala pacijente bez crnih obojenja (kontrola). Podaci su prikupljeni korištenjem posebno pripremljenog upitnika. Atomska apsorpcijska spektroskopija je primijenjena za odre-đivanje elemenata koji uzrokuju i nalaze se u sastavu crnih obojenja zubi. Test rizika karijesa (CRT) korišten je za određivanje puferskog kapaciteta sline, dok je CRT test bakterija korišten za određivanje prisutnosti bakterija Streptococcus mutansi Lactobacillusspp. u slini. Statistički značajna razlika između skupina utvrđena je za kelj i ciklu (p<0,05), no ne i za ostalo povrće. Što se tiče konzumacije pića, pacijenti s crnim obojenjima na zubima su pili manje vina (p<0,05) u odnosu na pacijente bez obojenja. Nije zabilježena razlika u konzumaciji lijekova između pacijenata s crnim obojenjima i bez njih. Pacijenti s obojenjima su bili stariji, pušili su i imali su niži pH sline te nižu razinu bakterije Streptococcus mutansnego oni bez obojenja (p<0,05). U diskoloriranim uzorcima pronađeni su tragovi kalcija, magnezija, željeza, bakra i cinka. Na nastanak obojenja zuba utječe niz čimbenika, među kojima se prehrana i slina smatraju jednim od važnijih. Ovo istraživanje je pokazalo da pacijenti s crnim obojenjima na zubima konzumiraju više cikle, dok pacijenti bez obojenja konzumiraju više kelja i crnog vina

Atmospheric Pressure Plasma Jet as an Accelerator of Tooth Bleaching

Svrha: Željela se ispitati učinkovitost atmosferskoga plazmenog mlaza (APM) kao izvora svjetlosti čiji učinak može brže razlagati vodikov peroksid u gelovima za izbjeljivanje i tako potaknuti brže i bolje izbjeljivanje. Materijali i metode: U zeleni čaj je osam sati bilo uronjeno 25 pastila hidroksilapatita. Nakon toga su osušene i podijeljene u pet skupina s po pet pastila. Uzorci su posebno tretirani gelovima za izbjeljivanje s 30-postotnim i 40-postotnim vodikovim peroksidom te u kombinaciji s atmosferskom plazmom. Tijekom procesa izbjeljivanja analizirana je optička emisijska spektroskopija i temperatura s pomoću pirometra. Boja pastila bila je određena RGB kolorimetrom. Za mjerenje pH vrijednosti korišteno je prije i poslije tretmana dodatnih 10 pastila kojima je pH izmjeren kontaktnim pH-metrom. Rezultati: Analizom promjene boja na pastilama prije i poslije tretmana, pokazano je da APM u kombinaciji s gelovima za izbjeljivanje poboljšava izbjeljivanje 32, odnosno 15 posto. Postupak izbjeljivanja s pomoću APM-a imao je bolji učinak u šest puta kraćem vremenu u odnosu prema tretmanu koji je predložio proizvođač. Optičkom emisijskom spektroskopijom dokazana je kemijska aktivnost plazme. Nakon tretmana APM-om, pH vrijednosti gela za izbjeljivanje pale su na 50 do 75 posto početnih vrijednosti, a temperatura na površini tretiranog uzorka porasla je s 8 na 10˚C u odnosu prema početnim vrijednostima. Zaključak: Uporaba atmosferskoga plazmenog mlaza u kombinaciji s gelovima za izbjeljivanje daje bolje rezultate u kraćem vremenu i ne povećava temperaturu koja može oštetiti okolno tkivo.Objective: To study the effect of atmospheric pressure plasma (APP) jet as a potential accelerator of the degradation of hydrogen peroxide in bleaching gels which could lead to better and faster bleaching. Material and Methods: 25 pastilles of hydroxylapatite were colored in green tea for 8 hours and were randomly divided into five groups (n = 5). The bleaching process was performed with 30% and 40% hydrogen peroxide (HP) gel alone and in conjunction with helium APP jet. During the bleaching treatment, optical emission spectroscopy and non-contact surface temperature measurement using pyrometer were performed. Color of the pastilles was determined by a red– green–blue (RGB) colorimeter. PH values of bleaching gels were measured before and after the plasma treatment on additional 10 pastilles using a pH meter with contact pH electrode. Results: The color measurements of pastilles before and after the treatment showed that treatment with APP jet improved the bleaching effect by 32% and 15% in the case of 30 % and 40% HP gel. Better results were obtained approximately six times faster than with a procedure suggested by the bleaching gel manufacturer. Optical emission spectroscopy proved that plasma has a chemically active role on the gel. After the APP treatment, pH values of bleaching gels dropped to about 50–75% of their initial value while the surface temperature increased by 8–10˚C above baseline. Conclusion: The use of plasma jet provides more effective bleaching results in a shorter period of time without a significant temperature increase which may cause damage of the surrounding tissue

Postoperative Sensitivity after Two in-Office Bleaching Methods

Svrha: Željelo se odrediti stupanj postoperativne preosjetljivosti nakon uporabe dvaju sredstava za profesionalno izbjeljivanje vitalnih zuba. Materijal i postupci: Istraživanje je provedeno na 22 ispitanika podijeljena u dvije skupine (po 11 sudionika) koji su dobrovoljno pristali na postupak izbjeljivanja zuba. Koristili smo se dvama preparatima za profesionalno izbjeljivanje – 25-postotnim vodikovim peroksidom Zoom 2 uz svjetlosnu aktivaciju izvorom svjetlosti te 38-postotnim vodikovim peroksidom Opalescence Boost bez aktivacijskog učinka izvora svjetlosti. Preosjetljivost se ocjenjivala na vizualno analognoj ljestvici (VAS-u) odmah nakon postupka, te 6 i 24 sata poslije izbjeljivanja. Rezultati: Rezultati su analizirani testom Wilcoxon Rank Sum. Razlika između postoperativne preosjetljivosti kod izbjeljivanja preparatima Zoom 2 i Boost, izmjerena odmah te 6 i 24 sata poslije izbjeljivanja, nije bila statistički značajna (p>0,05). Kod oba preparata postoperativna preosjetljivost bila je najizraženija odmah nakon postupka te 6 sati poslije izbjeljivanja (p<0,05). Dakle, ispitanici su pokazali jasnu pojavu postoperativne preosjetljivosti, no smanjivala se prema vrijednostima izmjerenima 24 sata poslije zahvata. Zaključak: Postoperativna bol i preosjetljivost tijekom obaju postupaka izbjeljivanja s različitim koncentracijama vodikova peroksida te nakon njih, moguće su nuspojave koje su najizraženije odmah nakon postupka te poslije šest sati, smanjujući se prema vrijednostima izmjerenima 24 sata nakon izbjeljivanja.Aim: The aim of this study was to measure the level of postoperative sensitivity after two in-office whitening treatments. Materials and Methods: Twenty-two patients, divided in two groups of 11, took part in this study and they voluntarily agreed to a bleaching treatment. Two different in-office bleaching agents were used: Zoom2, based on 25% hydrogen peroxide and initialized by the light source from the same manufacturer, and Opalescence Boost, based on 38% hydrogen peroxide without the light initiation. The pain was evaluated by the visual analogue scale (VAS) and the data were recorded immediately, and at 6 and 24 hours after bleaching. Results: The data were analyzed by Wilcoxon Signed Rank Test. The difference between postoperative sensitivity after application of Zoom2 and Boost whitening agents, measured immediately after the treatment, 6 and 24 hours after bleaching, was not statistically significant (p>0.05). Both whitening treatments show the same prevalence of postoperative sensitivity, which was the highest immediately after the treatment and 6 hours later (p<0.05). Both agents show obvious appearance of postoperative sensitivity, which decreases to the values measured 24 hours after the treatment. Conclusion: The postoperative pain and sensitivity during and after both in-office whitening treatment agents with different hydrogen peroxide concentrations occur as one of the possible side-effects which were the highest immediately after the treatment and 6 hours later, and then decreasing to the values measured 24 hours after the treatment