OBJECTIVES: This study investigated the effect of red and white wine on color changes of nanofilled and nanohybrid resin composite. MATERIALS AND METHODS: Sixty specimens of each resin composite were prepared. Baseline data color values were recorded using a spectrophotometer. Three groups of discs (n = 20) were then alternately immersed in red, white wine, and deionized water (as a control) for twenty five minutes and artificial saliva for five minutes for four cycles. Specimens were then stored in artificial saliva for twenty two hours. This process was repeated for five days following immersion in artificial saliva for two days. Subsequently, the process was repeated again. Data were analyzed by two-way repeated ANOVA, one-way ANOVA, and Tukey's HSD. RESULTS: Red wine caused significantly higher color change (ΔE* > 3.3) than did white wine and deionized water (p < 0.05). Nanohybrid resin composites had significantly more color changes than nanofilled resin composite (p < 0.05). CONCLUSIONS: The effect of red and white wine on the color changes of resin composite restorative materials depended upon the physical and chemical composition of the restorative materials and the types of wine.
Immersion ; Saliva, Artificial ; Water ; Wine*

PURPOSE: To evaluate and compare the effect of different materials and techniques on the shear bond strength of veneering ceramic materials to zirconia. MATERIALS AND METHODS: 136 sintered zirconia cubes were prepared and randomly divided into four study groups according to corresponding methods of surface treatment and materials: GLN (grinding followed by laser scanning using Noritake Cerabien ZR), SLN (sandblasting followed by laser scanning using Noritake Cerabien ZR), GLV (grinding followed by laser scanning using VITA VM 9), and SLV (sandblasting followed by laser scanning using VITA VM 9). Spraying technique was performed to coat the core. Profilometer, SEM, XRD, EDS, universal testing machine, and stereomicroscope were used to record surface roughness Ra, surface morphology, phase transformation, elemental compositions, shear bond strength SBS values, and failure types, respectively. Specimens were investigated in unaged (not immersed in artificial saliva) and aged (stored in artificial saliva for a month) conditions to evaluate SBS values. RESULTS: Grinding and GLN as first and second surface treatments provided satisfactory Ra values in both conditions (1.05 ± 0.24 µm, 1.30 ± 0.21 µm) compared to sandblasting and other groups (P < .05). The group GLN showed the highest SBS values in both conditions (30.97 ± 3.12 MPa, 29.09 ± 4.17 MPa), while group SLV recorded the lowest (23.96 ± 3.60 MPa, 22.95 ± 3.68 Mpa) (P < .05). Sandblasting showed phase transformation from t-m. Mixed failure type was the commonest among all groups. CONCLUSION: GLN showed to be a reliable method which provided satisfactory bond strength between the veneer ceramic and zirconia. This method might preserve the integrity of fixed dental crowns.
Ceramics ; Crowns ; Methods ; Saliva, Artificial

PURPOSE: With gold electroforming system for the double crown, the secondary crown is electroformed directly onto the primary crown. An even thick layer of high precision can be acquired. It is thought that the retention of electroformed outer crown is primarily acquired by the adhesive force (surface tension) through the saliva which is interposed between precisely fitted inner and outer crown. The purpose of this study was to investigate the effect of taper and surface area of inner crown on the retentive force of electroformed outer crown according to the presence of saliva. MATERIALS AND METHODS: 32 titanium inner crowns with cervical diameter of 8 mm and cone angles of 0, 2, 4, 6 degrees, which had same surface area by regulated height, were machined on a lathe. Another 32 titanium inner crowns with cone angles of 0, 2, 4, 6 degrees, which had doubled surface area by increased cervical diameter, were fabricated. Eight specimens of each group, for a total of 64 titanium inner crowns, were prepared. The electroformed outer crowns were fabricated directly on the inner crowns by using electroforming machine(GAMMAT free, Gramm Technik, Germany). The tertiary frameworks were waxed-up on the electroformed outer crown and cast using nonprecious alloy(Rexillium(R)III, Jeneric(R)/ Pentronh(R) Inc., USA). The cast metal frameworks were sandblasted with alubimium oxides and cemented using resin cement(Superbond C and B, Sun Medical Co., Japan) over the electroformed copings of each specimen. Then, artificial saliva(Taliva(R), Halim Pharm Co., Korea) was sprayed between the inner and outer crown, and they were connected under 5 kg force. The retentive force was measured by the universal testing machine(Tinius Olsen 1000, Tinius Olsen, USA) with a cross-head speed of 66.67 mm/sec. The direction of cross-head travel was exactly aligned with the path of removal of the respective specimens. This measurement procedures for retentive force of electroformed outer crown with artificial saliva were repeated in the same way without presence of artificial saliva. RESULTS AND CONCLUSION: The following conclusions were drawn: 1. The retentive force of electroformed outer crown was decreased according to increased taper of inner crown(P<.05). 2. The retentive force of electroformed outer crown showed no significant differences according to surface area and the presence of artificial saliva(P>.05).
Adhesives ; Crowns* ; Oxides ; Saliva ; Saliva, Artificial ; Solar System ; Titanium

The purpose of this study was to evaluate the clinical effectiveness of hydrophilic primer, which claim to retain adequate bond strength on moistened enamel resulting from moisture or saliva contamination, by comparing the shear bond strength and adhesive failure patterns of brackets bonded using hydrophilic primer and conventional hydrophobic primer. Brackets were bonded to human premolars embedded in metal cylinders utilizing light cured adhesive, primed with either a hydrophilic primer(Transbond MIP primer) or a conventional hydrophobic primer(Transbond XT primer). Each sample was exposed to varying degrees of artificial saliva contamination during the priming process. The shear bond strength was measured using a universal testing machine, and the adhesive failure patterns after debonding were visually examined by stereomicroscope and assessed using the adhesive remnant index(ARI). The results were as follows: 1. In dry conditions, no significant differences in shear bond strength between Transbond MIP and Transbond XT primers were found. 2. Transbond MIP primer exhibited a significantly higher shear bond strength than Transbond XT primer in saliva-contaminated conditions, regardless of the degree of contamination. 3. When contaminated with one coat of saliva, Transbond MIP primer did not exhibit significant differences in shear bond strength compared to the dry condition. When contaminated with two coats of saliva, Transbond MIP primer exhibited a significantly lower shear bond strength compared to the dry condition. 4. The adhesive remnant index of the adhesive failure pattern had a tendency to decrease, as the degree of saliva contamination increased. Bracket-adhesive interface failure was observed in more than half of the saliva contaminated samples utilizing Transbond MIP primer, whereas the bond failure sites of the Transbond XT primer samples occurred almost exclusively at the adhesive-enamel interface in saliva-contaminated conditions. The results of this study suggest that in cases where moisture control is difficult, Transbond MIP primer is an effective alternative to conventional hydrophobic primers.
Adhesives ; Bicuspid ; Dental Enamel ; Humans ; Orthodontic Brackets* ; Saliva ; Saliva, Artificial

Translational movement along an arch wire requires sufficient force to overcome frictional forces between bracket and arch wire. The orthodontist must appreciate the importance of friction in this process, and study out the influencing factors on the level of friction. The purpose of this study was to evaluate the effect of artificial saliva on frictional resistances generated between the bracket and arch wire. Independent variables of this study were arch wire material, angulation and environment. Static frictional forces of cobalt-chromium, heat-treated cobalt-chromium, beta-titanium, stainless steel wires were measured under non-angulated dry, angulated dry, non-angulated saliva, angulated saliva conditions. The results were as follows : 1. Stainless steel wires showed lower friction values in non-angulated dry condition, and heat-treated cobalt-chromium wires showed higher friction values in angulated dry condition. Higher friction values were showed in order of cobalt-chromium, stainless steel, heat-treated cobalt-chromium and beta-titanium wires in non-angulated saliva condition, and were showed in order of stainless steel, cobalt-chromium, heat-treated cobalt-chromium, beta-titanium wires in angulated saliva condition. 2. Angulation increased friction for stainless steel wires under dry condition. 3. Artificial saliva decreased friction for cobalt-chromium wires and increased friction for stainless steel wires under non-angulated condition. 4. Artificial saliva decreased friction for all wires except beta-titanium wires under angulated condition. 5. Regardless of angulation or environment, heat-treated cobalt-chromium and beta-titanium wires showed higher friction values, and stainless steel wires showed lower friction values.
Friction* ; Orthodontic Wires* ; Saliva ; Saliva, Artificial* ; Stainless Steel

OBJECTIVE: We evaluated the effects of tooth displacement on frictional force when conventional ligating lingual brackets (CL-LBs), CL-LBs with a narrow bracket width, and self-ligating lingual brackets (SL-LBs) were used with initial leveling and alignment wires. METHODS: CL-LBs (7th Generation), CL-LBs with a narrow bracket width (STb), and SL-LBs (In-Ovation L) were tested under three tooth displacement conditions: no displacement (control); a 2-mm palatal displacement (PD) of the maxillary right lateral incisor (MXLI); and a 2-mm gingival displacement (GD) of the maxillary right canine (MXC) (nine groups, n = 7 per group). A stereolithographic typodont system and artificial saliva were used. Static and kinetic frictional forces (SFF and KFF, respectively) were measured while drawing a 0.013-inch copper-nickel-titanium archwire through brackets at 0.5 mm/min for 5 minutes at 36.5℃. RESULTS: The In-Ovation L exhibited lower SFF under control conditions and lower KFF under all displacement conditions than the 7th Generation and STb (all p < 0.001). No significant difference in SFF existed between the In-Ovation L and STb for a 2-mm GD of the MXC and 2-mm PD of the MXLI. A 2-mm GD of the MXC produced higher SFF and KFF than a 2-mm PD of the MXLI in all brackets (all p < 0.001). CONCLUSIONS: CL-LBs with narrow bracket widths exhibited higher KFF than SL-LBs under tooth displacement conditions. CL-LBs and ligation methods should be developed to produce SFF and KFF as low as those in SL-LBs during the initial and leveling stage.
Friction* ; Incisor ; Ligation ; Saliva, Artificial ; Tooth*

OBJECTIVETo investigate the effect of the laser surface hardening technology on the corrosion resistance of dental casting alloy.

METHODSTwenty-three cobalt-chromium alloy specimens were made in this study. Twenty-two specimens were equally divided into two groups randomly. One was experimental group for laser surface hardening processing and the other was control group without any treatment. In each group, ten specimens were used for corrosion analysis by electrochemical method, and one for surface metallographical structure and morphology observation by scanning electron microscope. Remaining one specimen was partially processed on limited area for surface metallographical structure and morphology comparison.

RESULTSMetal grains distributed uniformly and achieved a good refinement with mainly the same size in experimental group. Metal grains in specimen which processed in its partial surface area also achieved a good refinement in the laser processing area. There was statistical difference in electric potential of corrosion and logarithmic value of current of corrosion between experimental group and control group (P < 0.01).

CONCLUSIONLaser surface hardening technology has a positive effect in improving the corrosion resistance of dental casting alloy in artificial saliva.

OBJECTIVE: The purpose of this study was to evaluate how the friction that occurs during the sliding movement of the archwire through esthetic brackets is differently affected by bracket materials, slot designs, and tip angulations of the archwire. METHODS: Eight types of brackets with 0.018 inch slots (composite: Brillant (BR); composite with metal slot: Spirit MB (SP); ceramic: Inspire (IN), Signature (SI), Cristaline V (CR); ceramic with metal slot: Clarity (CL), Luxi II (LU); and metal bracket: Integra (IT)), and placed into groups of 20 brackets in each group, were tested in artificial saliva with 0.018 inch stainless steel wire. The wire tip angulations were given as 0, 4 and 8 degrees. RESULTS: CR group significantly showed the lowest frictional force with all wire tip angulations of 0, 4, and 8 degrees. IN significantly showed the highest frictional force (p < 0.001). BR (polyoxymethylene) had significantly less frictional force than SP (polycarbonate) (p < 0.001) and showed no significant difference between metal brackets. Friction was increased as the wire tip angulations were increased, but no notches were observed on any parts of the archwire. CONCLUSIONS: According to the results of this study, esthetic brackets are superior or similar to SS brackets from a frictional point of view.
Ceramics ; Friction* ; Saliva, Artificial ; Stainless Steel

The purpose of this study was to investigate the change of 3 point bending properties of various nickel titanium wires after recycling. Four types of nickel-titanium (Align: martensitic type, NiTi, Optimalloy, Sentalloy: austenitic type) wires were divided to three groups: as-received condition (T0: control group), treated in artificial saliva for four weeks (T1) and autoclaved after being treated in artificial saliva (T2). Detrimental changes were observed for the selected mechanical properties in three point bending test. Loading force at 3mm deflection, unloading force at 3mm deflection, stress hysteresis, loading force at 1mm deflection, unloading force at 1 mm deflection and stress hysteresis at 1mm deflection were calculated. The findings suggest that: 1. Align demonstrated statistically significant increase in loading force (p<0.05) and unloading force (p<0.01) at 3mm deflection after recycling(T2), but NiTi, Optimalloy and Sentalloy showed no statistically difference after recycling. 2. Align demonstrated statistically significant decrease in hysteresis(p<0.01) after recycling(T2) but NiTi, Optimalloy and Sentalloy showed no statistically significant difference after recycling. 3. All wires showed no statistically significant difference in loading force at 1mm deflection after recycling(T2). 4. Align demonstrated statistically significant decrease in unloading force in 1mm deflection (p<0.05) after recycling(T2) but NiTi, Optimalloy and Sentalloy showed no statistically difference after recycling. 5. Loading force and unloading force of T1 showed no significant change compared with those of T0, but loading force and unloading force of T2 showed significant changes compared with those of T0(p<0.05, p<0.01 respectively). 6. Align demonstrated a tendency to lose some of this pseudoelsticity in T1 and pseudoplasticity and pseudoelasticity in T2.
Alloys* ; Nickel ; Recycling ; Saliva, Artificial ; Titanium

PURPOSE: Impact forces in implant supported FDP (fixed dental prosthesis) are higher than that of tooth supported FDPs and the compositions used in frameworks also has a paramount role for biomechanical reasons. The aim of this study was to evaluate the flexural strength of two different zirconia frameworks. MATERIALS AND METHODS: Two implant abutments with 3.8 mm and 4.5 mm platform were used as premolar and molar. They were mounted vertically in an acrylic resin block. A model with steel retainers and removable abutments was fabricated by milling machine; and 10 FDP frameworks were fabricated for each Biodenta and Cercon systems. All samples were thermo-cycled for 2000 times in 5-55degrees C temperature and embedded in 37degrees C artificial saliva for one week. The flexural test was done by a rod with 2 mm ending diameter which was applied to the multi-electromechanical machine. The force was inserted until observing fracture. The collected data were analyzed with SPSS software ver.15, using Weibull modulus and independent t-test with the level of significance at alpha=.05. RESULTS: The mean load bearing capacity values were higher in Biodenta but with no significant differences (P>.05). The Biodenta frameworks showed higher load bearing capacity (F0=1700) than Cercon frameworks (F0=1520) but the reliability (m) was higher in Cercon (m=7.5). CONCLUSION: There was no significant difference between flexural strengths of both zirconia based framework systems; and both Biodenta and Cercon systems are capable to withstand biting force (even parafunctions) in posterior implant-supported bridges with no significant differences.
Bicuspid ; Molar ; Saliva, Artificial ; Steel ; Tooth ; Weight-Bearing