INFLUENCE OF SUBSTRATE COLOR, OPTICAL PROPERTIES AND THICKNESS OF RESTORATIVE MATERIALS AND LUTING AGENTS ON THE FINAL COLOR OF LITHIUM DISILICATE RESTORATIONS

Svrha je istraživanja bila odrediti utjecaj različitih boja podloge (Natural Die ND1, ND3, ND5, ND7 i ND9) i cementa (Variolink II transparentni, bijeli, opakno bijeli, žuti i smeđi) dviju debljinā (80 i 150 μm) na boju uzoraka litij-disilikatne keramike (LiS2) IPS e.max Press u četiri debljine (0,5, 0,8, 1,0 i 1,2 mm) i tri stupnja translucencije (HT, LT i MO) sa ili bez obložne keramike IPS e.max Ceram, debljinā 0,3, 0,5 i 0,8 mm. Izrađeno je ukupno 120 uzoraka (pločice Ø 11 mm) LiS2 keramike (10/skupina), 30 obložne keramike (10/skupina) i 55 ND podloga (11/boja). Na pet je podloga svake boje zalijepljen 80, a na drugih pet 150 μm debeo sloj kompozitnog cementa u pet različitih boja. Po jedna pločica bez cementa služila je kao kontrola. Pločice LiS2 preklapane su u svim kombinacijama s podlogama bez pa sa cementom te su spektrofotometrom izmjerene L*a*b* vrijednosti. Mjerenja su ponovljena i s obložnom keramikom. Izračunate su razlike u boji ΔE* te su podaci obrađeni u programu STATISTICA 10.0 primjenom ANOVA-e. Utvrđeno je kako su boja podloge, debljina i stupanj translucencije LiS2 keramike, boja i debljina cementa te debljina obložne keramike statistički značajno (p < 0,001 za sve varijable) utjecali na parametre boje modela koji je simulirao LiS2 nadomjestak. Unatoč statistički značajnom utjecaju boje i debljine cementa, samo je opakno bijeli cement uzrokovao i klinički značajnije razlike u boji. Obložna keramika statistički je značajno utjecala na parametre boje, pri čemu je, osim posvjeteljenja uzoraka, njenim dodavanjem klinički utjecaj cementa smanjen. Za uspješnu reprodukciju boje potrebno je uzeti u obzir debljinu nadomjeska, podlogu, a uvjetno i boju cementa.Objectives: The aim of the study was to evaluate the effect of different supstrate colors, luting agent colors and thicknesses, different thicknesses and translucency levels of core ceramics, and different thicknesses of veneering ceramics on the final color of a model representing lithium-disilicate restorations. Materials and methods: Cylindrical specimen of Natural Die material in the dimensions 11 x 5 mm were prepared in the colors ND1, ND3, ND5, ND7 and ND9 – 11 cylinders of each color. Disc specimen Ø 11 mm of IPS e.max Press LiS2 ceramics in 4 different thicknesses (0.5, 0.7, 1.0 and 1.2 mm) and 3 translucency levels (HT, LT and MO) were heat-pressed, and 3 thicknesses (0.3, 0.5, 0.8 mm) of IPS e.max Ceram veneering ceramics were prepared. That resulted in a total of 120 e.max Press specimen (4 thicknesses x 3 translucency levels x n = 10), 30 IPS e.max Ceram specimen (3 thicknesses x n =10), and 55 Natural Die specimen (5 colors x n = 11). One ND disc of each color served as control, while on the other 10 a layer of Variolink II resin cement in 5 different colors (transparent, white, white opaque, yellow and brown) and two thicknesses (80 or 150 μm) was applied. Different combinations of core discs with or without veneering ceramics were overlapped with the background discs with and without the cement layer to measure L*a*b* values using a spectrophotometer. Color differences ΔE* were calculated and data was statistically analyzed by means of STATISTICA 10.0. Analysis of variance (ANOVA) was applied. Results: A significant influence of supstrate color (p < 0,001), thickness (p < 0,001) and translucency level (p < 0,001) of LiS2 ceramics, color (p < 0,001) and thickness (p < 0,001) of luting agent, and the thickness of veneering ceramics (p < 0,001) on the color parameters was found. Despite the fact that the color and thickness of the luting agent had a statistically significant effect, only the white opaque cement caused clinically significant, i.e. visible color shifts. Veneering ceramics of varying thickness had a statistically significant impact on the color parameters of the model which simulated an all ceramic restoration, whereby, besides increasing lightness of the samples, a decrease of the clinical impact of underlying colors (supstrate and luting agent) was noticed. Conclusion: For optimum color-matching results the thickness of the restoration, supstrate, and conditionally luting agent color need to be taken into account

INFLUENCE OF SUBSTRATE COLOR, OPTICAL PROPERTIES AND THICKNESS OF RESTORATIVE MATERIALS AND LUTING AGENTS ON THE FINAL COLOR OF LITHIUM DISILICATE RESTORATIONS

Svrha je istraživanja bila odrediti utjecaj različitih boja podloge (Natural Die ND1, ND3, ND5, ND7 i ND9) i cementa (Variolink II transparentni, bijeli, opakno bijeli, žuti i smeđi) dviju debljinā (80 i 150 μm) na boju uzoraka litij-disilikatne keramike (LiS2) IPS e.max Press u četiri debljine (0,5, 0,8, 1,0 i 1,2 mm) i tri stupnja translucencije (HT, LT i MO) sa ili bez obložne keramike IPS e.max Ceram, debljinā 0,3, 0,5 i 0,8 mm. Izrađeno je ukupno 120 uzoraka (pločice Ø 11 mm) LiS2 keramike (10/skupina), 30 obložne keramike (10/skupina) i 55 ND podloga (11/boja). Na pet je podloga svake boje zalijepljen 80, a na drugih pet 150 μm debeo sloj kompozitnog cementa u pet različitih boja. Po jedna pločica bez cementa služila je kao kontrola. Pločice LiS2 preklapane su u svim kombinacijama s podlogama bez pa sa cementom te su spektrofotometrom izmjerene L*a*b* vrijednosti. Mjerenja su ponovljena i s obložnom keramikom. Izračunate su razlike u boji ΔE* te su podaci obrađeni u programu STATISTICA 10.0 primjenom ANOVA-e. Utvrđeno je kako su boja podloge, debljina i stupanj translucencije LiS2 keramike, boja i debljina cementa te debljina obložne keramike statistički značajno (p < 0,001 za sve varijable) utjecali na parametre boje modela koji je simulirao LiS2 nadomjestak. Unatoč statistički značajnom utjecaju boje i debljine cementa, samo je opakno bijeli cement uzrokovao i klinički značajnije razlike u boji. Obložna keramika statistički je značajno utjecala na parametre boje, pri čemu je, osim posvjeteljenja uzoraka, njenim dodavanjem klinički utjecaj cementa smanjen. Za uspješnu reprodukciju boje potrebno je uzeti u obzir debljinu nadomjeska, podlogu, a uvjetno i boju cementa.Objectives: The aim of the study was to evaluate the effect of different supstrate colors, luting agent colors and thicknesses, different thicknesses and translucency levels of core ceramics, and different thicknesses of veneering ceramics on the final color of a model representing lithium-disilicate restorations. Materials and methods: Cylindrical specimen of Natural Die material in the dimensions 11 x 5 mm were prepared in the colors ND1, ND3, ND5, ND7 and ND9 – 11 cylinders of each color. Disc specimen Ø 11 mm of IPS e.max Press LiS2 ceramics in 4 different thicknesses (0.5, 0.7, 1.0 and 1.2 mm) and 3 translucency levels (HT, LT and MO) were heat-pressed, and 3 thicknesses (0.3, 0.5, 0.8 mm) of IPS e.max Ceram veneering ceramics were prepared. That resulted in a total of 120 e.max Press specimen (4 thicknesses x 3 translucency levels x n = 10), 30 IPS e.max Ceram specimen (3 thicknesses x n =10), and 55 Natural Die specimen (5 colors x n = 11). One ND disc of each color served as control, while on the other 10 a layer of Variolink II resin cement in 5 different colors (transparent, white, white opaque, yellow and brown) and two thicknesses (80 or 150 μm) was applied. Different combinations of core discs with or without veneering ceramics were overlapped with the background discs with and without the cement layer to measure L*a*b* values using a spectrophotometer. Color differences ΔE* were calculated and data was statistically analyzed by means of STATISTICA 10.0. Analysis of variance (ANOVA) was applied. Results: A significant influence of supstrate color (p < 0,001), thickness (p < 0,001) and translucency level (p < 0,001) of LiS2 ceramics, color (p < 0,001) and thickness (p < 0,001) of luting agent, and the thickness of veneering ceramics (p < 0,001) on the color parameters was found. Despite the fact that the color and thickness of the luting agent had a statistically significant effect, only the white opaque cement caused clinically significant, i.e. visible color shifts. Veneering ceramics of varying thickness had a statistically significant impact on the color parameters of the model which simulated an all ceramic restoration, whereby, besides increasing lightness of the samples, a decrease of the clinical impact of underlying colors (supstrate and luting agent) was noticed. Conclusion: For optimum color-matching results the thickness of the restoration, supstrate, and conditionally luting agent color need to be taken into account

Analysis of Translucency Parameter of Glass-Ceramics Fabricated by Different Techniques

Svrha: Analizirati parametar translucencije (TP vrijednosti) staklokeramika izrađenih različitim tehnološkim postupcima te ispitati kako na TP vrijednosti utječu korozivna sredstva. Materijali i metode: Izrađena su po tri uzorka IPS e.max keramike (Ivoclar Vivadent, Schaan, Lihtenštajn) u trima bojama (A2, C2 i B3) s trima različitim tehnologijama izrade (slojevanje – e.max Ceram Dentin; toplo-tlačna tehnika – e.max Press; strojno – e.max CAD). Uzorci su bili u obliku pločica dimenzija 10 mm x 12 mm x 0,8 mm. Spektrofotometrom (X-Rite DTP 20 Pulse, Neu Isenburg, Njemačka) izmjerene su CIE L*a*b* vrijednosti za izračun parametra tanslucencije (TP vrijednost) prije i poslije izlaganja 4-postotnoj octenoj kiselini na 80 °C tijekom 16 sati (ISO 6872). Statistički podatci obrađeni su programom IBM SPSS 22. Rezultati: Značajno najmanje TP vrijednosti imao je IPS e.max Ceram Dentin, a najveće IPS e.max Press u svim bojama, prije i poslije izlaganja kiselini (p<0,001). Razlika u TP vrijednostima između boja bila je vidljiva unutar materijala IPS e.max Ceram Dentin prije i poslije izlaganja kiselini, uz veliku snagu efekta (p<0,001; η2 = 0,702 i 0,741) te pri primjeni materijala IPS e.max Press (p<0,001, snaga efekta 0,547 i 0,576). Strojno izrađeni uzorci pokazali su ujednačene TP vrijednosti. Izlaganje korozivnom sredstvu nije rezultiralo statistički značajnim promjenama TP vrijednosti ni za jedan materijal. Zaključak: Različite staklokeramike pokazale su značajne razlike u TP vrijednostima i prema tehnološkom postupku izrade i prema različitim bojama. Izlaganje korozivnom sredstvu nije rezultiralo statistički značajnim promjenama TP vrijednosti.The purpose of the study was to analyse translucency parameter (TP values) of glass-ceramics fabricated by different techniques and investigate the effect of the corrosive medium on TP values. Materials and methods: Three specimens of each type of IPS e.max ceramics (Ivoclar Vivadent, Schaan, Liechtenstein) were made in three colours (A2, C2 and B3) by three fabrication techniques (layering – e.max Ceram Dentin; heat-pressing – e.max Press; CAD/CAM – e.max CAD). Specimens were made in the form of plates (10 mm x 12 mm x 0.8 mm). CIE L*a*b* values were measured by a spectrophotometer (X-Rite DTP 20 Pulse, Neu Isenburg, Germany) before and after exposure to 4% acetic acid at 80 °C for 16 hours (ISO 6872) to calculate translucency parameter (TP values). Statistical data were analysed using the IBM SPSS 22 software. Results: IPS e.max Ceram Dentin had significantly the lowest TP values, and IPS e.max Press the highest TP values of all colours (A2, C2, B3), both prior and after exposure to acid (p<0.001). The difference in TP values among colours was evident in the IPS e.max Ceram Dentin material, both before and after exposure to acid with a great effect size (p<0.001; η2 = 0.702 and 0.741), and in the IPS e.max Press material (p<0.001, effect size 0.547 and 0.576). CAD/CAD specimens showed uniform TP values between three colours. Further, exposure to a corrosive medium did not result in a statistically significant change of TP values in any of the materials tested. Conclusions: Different types of glass-ceramics showed significant difference in TP values both with respect to the fabrication technique and colour. Exposure to a corrosive medium did not result in a statistically significant change of TP values

Oral Hygiene and Gingival Health in Patients with Fixed Prosthodontic Appliances – A 12-Month Follow-Up

The aim of this study was to assess and observe the oral hygiene and gingival condition in patients before and after fixed prosthodontic therapy through a 12-month period in combination with oral hygiene instructions. It was also analysed how factors, such as type of fixed prosthodontic appliance, constructive material, the position of a fixed partial denture (FPD) in the mouth, age and gender influenced oral hygiene. The dental arches were divided into three segments each and teeth and gingiva were examined using the Plaque and Gingiva Index by Silness and Löe, and for the mineralized deposits assessment the Calculus Index by Green and Vermillion was employed. The preliminary examination was conducted before the prosthodontic therapy, and the reexaminations were carried out 14 days, 1, 6 and 12 months after crown and/or FPD placement. A total of 93 subjects from the original study group of 146 patients attended all clinical examinations, while the rest was excluded. The sample consisted of 60 women, 33 men at age between 21 and 95 (average 51.8). A total of 39 patients had single crowns (C), 50 FPDs and 5 C+FPD. The frequency of plaque found during the preliminary visit was higher than that found in the other periods (p<0.001). Patients with C showed better oral hygiene levels than patients with FPDs or C+FPDs (p=0.001). Our results revealed no significant difference in oral hygiene status among patients with FPDs made of different materials (p=0.083). The worst hygiene levels were found in patients with fixed prosthodontic appliances in both jaws (p=0.012). Younger patients showed better hygiene levels than the older ones (p=0.002). Our research showed that appropriate educational and motivational measures can lead to improved oral hygiene, even after FPD placement. Presumably, the oral health in a group of adult patients can be kept acceptable by providing a prophylactic oral hygiene program

Effects of Wire EDM on the Microstructure of P/M Titanium Samples

Komercijalno čisti titanij (CP Ti) se koristi u dentalnoj medicini zbog biokompatibilnosti, dobrih mehaničkih svojstava i otpornosti na koroziju. Konvencionalni proizvodni procesi izrade takvog titanija mogu utjecati na kvalitetu površine uzoraka i rezultirati slabim vezanjem CP Ti s dentalnom keramikom. Zato se uvode nove tehnologije proizvodnje titanija, primjerice metalurgija praha i oblikovanje na erozimatu s žicom (WEDM). Svrha ovog istraživanja jest odrediti utjecaj WEDM-a na površinu uzoraka P/M CP Ti proizvedenih za ispitivanje vezne čvrstoće prema normi ISO 9693. Materijali i metode: Osam uzoraka P/M CP Ti dimenzija prema normi ISO 9693 proizvedeno je korištenjem WEDM-a i podijeljeno u dvije grupe – u neobrađene i brušene. Površine obje grupe uzoraka analizirane su metodama SEM, EDS i XDR. Rezultati: Analize neobrađenih uzoraka metodama SEM i EDS pokazuju tanki sloj različitog sastava i frakture. Brušeni uzorci imaju homogenu strukturu bez fraktura. Analiza metodom XDR pokazuje visoku koncentraciju titanijevih oksida na površini neobrađenih uzoraka, a nakon brušenja dobivena je samo čista α-faza. Zaključak: WEDM je metoda prikladna za proizvodnju uzoraka prema normi ISO 9693, ako se uzorci naknadno bruse.Purpose: Commercially pure titanium (CP Ti) has been recognized in dentistry for its biocompatibility, good mechanical properties and corrosion resistance. Conventional manufacturing processes can affect surface quality and result in poor bonding of dental ceramics to CP Ti. This is why powder metallurgy (P/M) and wire electro-discharge machining (WEDM) are being introduced in the manufacturing process. The aim of this study was to evaluate the effect of WEDM on the surface composition and microstructure of P/M CP Ti samples produced for bond strength testing according to ISO 9693. Materials and methods: Eight samples of P/M CP Ti, dimensions according to ISO 9693, were made using WEDM and divided in two groups (untreated and grinded). Microanalyses of chemical composition and microstructure of both groups were made using SEM, EDS and XDR. Results: SEM and EDS analysis of untreated samples showed a thin layer on surfaces with fractures in it. Grinded samples showed homogenous structure with no layer and no fractures. XDR analysis showed high level of oxides on the surface of untreated samples, while after grinding only pure α-phase was found. Conclusion: WEDM is a suitable method of sample production for ISO 9693 if accompanied by grinding with silicon carbide papers P320-P4000