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Purpose: The objective of this study was to determine the effect of dental laser (DL) irradiation on the metalloproteinases (MMP)-mediated dentin collagen degradation. Methods: Human dentin disks were prepared (0.3 × 5x6mm, n = 60) and subjected to different treatments (n = 10/group): (1) control group (no treatment); (2) application of 37% phosphoric acid (PA) for 15 s; (3) irradiation with Er:YAG laser (120 mJ, 10 Hz); (4) irradiation with Er:YAG laser (120 mJ, 20 Hz); (5) irradiation with Er,Cr:YSGG laser (130mj, 30 Hz); and (6) irradiation with Er,Cr:YSGG laser (80mj, 50 Hz). After treatment, the total MMP activity and dry mass of each beam were measured, and after rehydration, they were incubated in 1 mL calcium- and zinc-containing incubation media for (a) one week and (b) three weeks. After each time point, dry mass changes were reassessed, and the aliquots of the incubation media were analyzed for pyridinoline-cross-link-containing degradation fragment of the C-terminal telopeptide of type I collagen (ICTP) using ELISA kits. All data were compared using ANOVA and Tukey’s test. Results: ANOVA showed significant differences among tested groups (p < 0.001). Laser-treated beams showed 55–75% less activity compared to 37% phosphoric acid-treated beams. The highest ICTP values were seen when PA was applied to the dentin surface in both time periods (p < 0.05). DL irradiation, be it with Er:YAG or Er,Cr:YSGG laser, did not increase the ICTP values in both time periods when compared with the control group (p > 0.05). Conclusion: The MMP-mediated dentin collagen degradation was the highest when PA was applied to the dentin surface and the lowest in Er:YAG or Er,Cr:YSGG laser-treated dentin groups in both time periods. Academy of Finland ; Turun Yliopistollinen Keskussairaala

Objective: This research aimed to evaluate the effect of different resin cement (RC) types, compare the effect of surface treatments and bonding applications and evaluate the effect of thermal cycling on bond strengths to Titanium (Ti) surfaces. Methods: A total of 240 Ti discs (10x3 mm) were randomly divided into two groups. Half of the specimens were sandblasted with 110 mu m Al2O3 particles, whereas the other half had no surface treatments (non-treated). Both sandblasted and non-treated specimens of each surface treatment type were divided into five subgroups, which received one of the following surface conditions and luting selfadhesive resin cement: (a) Panavia SA Cement, (b) Clearfil SE Bond + Panavia SA Cement, (c) RelyX U200, (d) Single Bond Universal + RelyX U200 and (e) MIS Crown Set Cement. A mould with a 4-mm diameter and 2-mm thickness was applied to the central region of the specimens. Each group was divided into subgroups, according to whether performing thermocycling or not. The shear bond tests were conducted at a crosshead speed of 1 mm/min. Data (N) were analysed using one-way analysis of variance and Tukey's honestly significant difference tests (p

The study evaluated changes in total enzymatic activity and degradation of demineralized dentin following the application of universal or self-etch adhesives. The universal adhesives -Scotchbond Universal (SU) and All-Bond Universal (ABU) and self-etch adhesives -Adper Easy Bond (EB) and G-aenial Bond (GB) were used for 2 min pretreatment of the dentin beams. Phosphoric acid (PA) treatment as well as no treatment served as controls. Total enzymatic activity was analyzed before and after treatment, collagen degradation was assessed using mass loss, C-terminal telopeptide (CTX) and C-terminal-telopeptide of type I collagen (ICTP) release (24 h, 3-day, 3-week). Over three weeks of incubation, ICTP release of ABU treated beams was significantly higher than other groups (p0.05) and CTX release of GB treated beams was the highest among the groups with statistically significant difference (p

To compare the effect of different surface treatments on the bond strength of CAD/CAM fabricated resin-based and prefabricated fiber posts to root canal dentin.160 single-rooted human teeth were selected and received endodontic treatment. The teeth were divided into four groups according to the post material used: (1) Prefabricated fiber-reinforced composite post (Snowpost), (2) CAD/CAM nanoceramic (Cerasmart), (3) CAD/CAM polymer infiltrated ceramic (Vita Enamic) and (4) CAD/CAM resin nanoceramic (Lava Ultimate). Then the posts were randomly assigned into four sub-groups according to the surface treatment method used: (1) Control (no treatment), (2) Laser (Er,Cr:YSGG laser device, Waterlase), (3) Hydrofluoric acid treatment [ 9.6% HF (Pulpdent) for 2 minutes], and (4) Sandblasting (50 µm Al2O3). Following post space preparation, posts were cemented with dual-cure resin cement (Panavia SA cement plus). From each root, five 1 mm-thick slices were obtained. The micropush-out bond strength test was performed for each slice. Data were analyzed by using two-way ANOVA and Tukey HSD tests. The fracture modes were evaluated under a stereomicroscope. Representative specimens were analyzed with SEM following surface treatments.Micropush-out bond strength of posts to dentin was significantly affected by the type of post material (P0.05), but not by the surface treatment (P= 0.397).Posts manufactured by CAD/CAM could be suitable options for restoration of severely affected endodontically-treated teeth.

Objective: This study compared the effects of different surface treatments on the surface roughness (Ra), and shear bond strength (SBS) of resin cement to yttria-stabilized tetragonal zirconia (Y-TZP) ceramic and nickel-chromium (Ni-Cr) base metal alloy, respectively. Materials and methods: Thirty disk-shaped specimens (3 mm height and 10 mm diameter) of each material (Y-TZP and Ni-Cr) were prepared. Both zirconia and metal specimens were randomly assigned to three equal groups, according to the surface treatments (n = 10): sandblasting, sandblasting + Er:YAG laser, and sandblasting + Nd:YAG laser. Resin cement cylinders (4 mm diameter and 3 mm thickness) were placed on each specimen. The SBS tests were performed at a 1 mm per minute crosshead speed through a knife-edge rod after 5000 thermal cycles. The Ra (μm) of the specimens was measured using a profilometer and evaluated topographically by atomic force microscopy and scanning electron microscopy. Analysis of variance, followed by Tukey's honestly significant difference, in addition to the Kruskal-Wallis test, followed by the Mann-Whitney U test, were used for statistical analysis (α = 0.05). Results: Combined sandblasting and laser treatment of the metal groups led to statistically higher Ra values than sandblasting alone (p < 0.05). For Y-TZP, there were no significant differences between the Ra values of the subgroups (p > 0.05). The SBS of the sandblasted metal group was significantly higher than the other two laser-irradiated groups, whereas the SBS of sandblasted zirconia was only significantly higher than the Nd:YAG laser-irradiated group (p < 0.05). Conclusions: Combined laser and sandblasting surface treatments resulted in rougher surfaces than sandblasting alone, especially for the metal specimens. Sandblasting, alone, improved the SBS of resin cement in both metal and zirconia, compared with the laser and sandblasting treatments, combined.

Objective: Ceramic glazing and polishing are important for patient satisfaction and long-term clinical success. Till date, no study has compared color changes after glazing procedures between conventional and more recently introduced ceramics. In this study, we investigated the effects of glazing procedures on the color stability of conventional and computer-aided design/computer-aided manufacturing (CAD/CAM) hybrid ceramics using a spectrophotometer.Materials and Methods: Eighty-four disc-shaped specimens were fabricated with seven different dental porcelain materials according to the manufacturers' instructions (n=12 each): Ivoclar IPS DSign, Vita Omega 900, Ceramco III, Vita Mark II, Vita Enamic, GC Cerasmart, and Vita Suprinity. Both sides of the specimens were polished with wet 600-, 1000-, and 1500-grit aluminium oxide abrasive papers, and color values (L*, a*, b*) were measured using a spectrophotometer before and after glazing. Treatment-induced changes in the specimen color and topography were evaluated and recorded. The color change (Delta E) was calculated from the changes in the mean L*, a*, and b* values. All data were analyzed using Kruskal-Wallis, Mann-Whitney U, and Wilcoxon tests (95% confidence interval).Results: Color changes were below the clinically perceptible level (Delta E

The etiology of marginal bone loss around osseointegrated implants is primarily based on the biomechanical and/or microbial factors. If stresses and strains around dental implants under functional loading conditions are expected to exceed the physiologic tolerance thresholds of the alveolar bone, the fixed hybrid prosthesis might be a more reliable treatment of choice instead of fixed metal ceramic restorations. The purpose of this article is to report the 1-year follow-up of the periodontal and prosthetic rehabilitation of a patient who has presented with symptoms of peri-implantitis due to incorrectly planned implant supported fixed metal ceramic bridge which was later replaced with screw-retained hybrid prosthesis following the treatment of peri-implant defects. Treatment helped to maintain patient's self-confidence and comfort, as well as favorable masticatory function. Rehabilitation with screw retained hybrid prosthesis is an ideal treatment of choice for maxillomandibular skeletal discrepancies. Osseointegre implantların etrafındaki kemik kaybının etyolojisi, primer olarak biyomekanik ve/veya mikrobiyal faktörlere dayanır. İnsan çene kemiklerinde oluşan gerilme ve gerilim kuvvetlerinin fizyolojik tolerans eşiğinin üstünde olduğu durumlarda; sabit metal seramik restorasyonların yerine, sabit hibrid protezler daha güvenilir bir tedavi seçeneği olabilir. Bu olgu bildirisinin amacı, yanlış olarak planlanmış implant destekli sabit bir metal seramik köprüye sahip olan ve mevcut implantlarında peri-implantitis bulunan bir hastanın; peri-implant defektlerinin tedavisi sonrasında periodontal ve protetik rehabilitasyonun 1 yıllık takibini sunmaktır. Yapılan tedavi, hastanın hem özgüveninin ve rahatının kazandırılmasını, hem de etkili bir çiğneme fonksiyonuna sahip olmasını sağlamıştır. Vida retansiyonlu hibrid protezler ile yapılan oral rehabilitasyon, maksillomandibular iskeletsel malokluzyonlar için ideal bir tedavi seçeneğidir.

doi:10.1111/j.1741-2358.2009.00329.x Experiments on in vivo biofilm formation and in vitro adhesion of Candida species on polysiloxane liners Objectives: Microorganisms may colonise polysiloxane soft liners leading to bio-deterioration. The aim of this study was to investigate in vitro adhesion and in vivo biofilm formation of Candida species on polysiloxane surfaces. Methods: The materials used in this study were Molloplast B, GC Reline soft, Mollosil Plus, Silagum Comfort and Palapress Vario. The in vitro retention of clinical isolates of Candida albicans to the relining and denture-base materials by microscopic (scanning electron microscopy, SEM), conventional culturing methods and antimicrobial properties of these materials were studied. Candida found on materials and mucosa following long-term use were identified and quantified, and biofilms covering the surfaces were investigated by SEM. Results: There was a significant decrease in the number of cells attached in vitro to saliva-coated surfaces compared with non-treated surfaces. An oral Candida carriage of 78% was found. Candida albicans, C. glabrata, C. intermedia and C. tropicalis were identified. In vivo biofilm formation on the liners appeared as massive colonisation by microorganisms. Conclusions: The results of the in vitro experiments suggest that salivary film influences early colonisation of different C. albicans strains. The film layer also minimises the differences among different strains. The Candida carriage of these patients was similar to denture-wearing patients without soft liners.

WOS: 000247249800009, PubMed ID: 17621936, This study evaluated the color stability of soft denture liners after being exposed to coffee and tea solutions for different time periods. Four soft denture liners and a denture base polymer were tested. Five specimens of each material were immersed in either coffee or tea solution at 50 +/- 1 degrees C for one, three, nine, 24, 48, and 96 hours. Color measurements were made using a reflectance spectrophotometer before and after the specimens were exposed to the solutions. After 96 hours' immersion in coffee and tea solutions, coffee produced more marked color changes than did tea for all the materials tested. Surface roughness (Ra) of the materials after being cured against a stainless steel surface was also measured with a contact-type surface roughness measuring instrument. Due to the different surface structures, which thus accounted for the different Ra values, the materials behaved differently when immersed in different solutions.

Objective. The clinical survival rates of the adhesive restorations are limited due to the deterioration of resin-dentin bonds over time, partly due to the endogenous enzymatic activity of dentin. Recently, benzalkonium chloride (BAC) has been shown to effectively inhibit endogenous protease activity of dentin. This study evaluated the effect of different concentrations of benzalkonium chloride (BAC) on the degree of conversion (DC), vickers hardness (VH), setting time (ST) and biaxial flexural strength (FS) of two self-adhesive resin luting cements (RC). Methods. Two RC SpeedCEM (Ivoclar-Vivadent) and BisCem (Bisco) were modified by addition of 0.1, 0.5, 1, 1.5, 2 wt% BAC. The luting cements without the addition of BAC served as control. The DC (FT-IR/ATR from the bottom of the resin disc), vickers hardness (from top and bottom of the light-cured specimen), setting time (ISO 4049) and biaxial flexural strength (0.6 6 mm discs) of the specimens were tested. Data were analyzed using ANOVA and Tukeys HSD. Results. DC results were in the range of 70–80%, with some significant changes in BisCem (p < 0.05). VH values of both materials increased significantly compared to control, with no significant change as the BAC percentage increases. BAC addition influenced the ST differently for both materials. For BisCem, a gradual decrease (p < 0.05) was observed whereas, for SpeedCEM, a gradual increase was observed until 1% BAC (p < 0.05). For FS values, a gradual decrease was observed for both materials with increased amounts of BAC (p < 0.05), compared to the control group. Conclusions. BAC addition of up to 1% seems to be acceptable considering the properties tested. Clinical significance. Incorporation of benzalkonium chloride to self-adhesive resin luting cements during the mixing procedure does not significantly affect the degree of conversion or flexural strength of the luting agent and may be a good option to improve the durability of adhesive interface.

WOS: 000257977000016, PubMed ID: 18717174, Objective: The aim of the present study was to evaluate the clinical performance of four denture soft liners up to 12 months. Materials and methods: Thirty-three edentulous patients who experienced difficulties when using hard denture bases because of changes in denture-supporting tissues were accepted for the study and randomly received Molloplast B, GC Reline Soft, Silagum Comfort, or Mollosil Plus relines. Performance of the materials was evaluated using nine criteria at 3, 6, and 12 months: physical integrity, surface detail, adhesion, color, odor, plaque accumulation, resilience, hygiene, and mucosal condition. A four-point categorized scale (1=poor, 2=fair, 3=good, 4=excellent) was used. Unscheduled maintenance events and the presence of fungal colonization were also recorded. Results: The percentage of patients available at 3, 6, and 12 months were 91%, 91%, and 66%. Main reasons for dropouts and discontinuation were fractured dentures and patient dissatisfaction. At 6 months, 96% of the performance scores were good or excellent and the largest changes were observed for physical integrity, surface detail, color, and fungal colonization. Fungal colonization was the most commonly observed problem and was the only reason of failure at 12 months. Conclusions: The clinical performance of all soft liners was slightly impaired over the 12-month observation. Except for cases showing extensive fungal colonization, the observed changes in clinical performance did not necessitate remaking of the dentures. Mollosil Plus showed a performance comparable to that of Molloplast B, and the other materials had slightly lower performance especially in terms of fungal colonization.

WOS: 000247249800021, PubMed ID: 17621948, This study evaluated the effect of thermocycling on the tensile strength and tear resistance of four long-term soft denture liners. One light-activated (Astron Light, AL), two chemically activated (GC Reline Soft, GC; Silagum Comfort, SC), and one heat-cured (Molloplast-B, MLP) soft liner materials were tested. Dumbbell and trouser-leg specimen geometries were used for tensile strength and tear resistance tests, respectively. A total of 120 specimens were prepared. Test specimens for each material (n=5) were subjected to thermal cycling for 1,000 and 3,000 cycles between 5 degrees C and 55 degrees C in a thermocycler. Before thermocycling, AL gave the lowest tensile strength, while SC exhibited the highest tear resistance value among the materials tested (p

Self-adhesive resin cements (RCs) activate matrix metalloproteinase (MMP) and cathepsin-related collagen degradation, and gallic acid (GA) inhibits the activity of both MMPs and cysteine cathepsins. The purpose of this study was to evaluate the setting time, biaxial flexural strength, and Vickers hardness of self-adhesive RCs after the addition of two different concentrations of GA. RelyX U200 (3M ESPE) and Panavia SA (Kuraray) were modified with 0.5 and 1 wt% GA. The setting time of five samples in each RC group was assessed using a thermocouple apparatus as described in the ISO 4049 test. Biaxial flexure strength was measured using a universal testing machine until failure. Vickers hardness was measured with three randomized indentations on the surface of each resin disc. RCs without GA were used as control. Data were analyzed using a one-way analysis of variance and Tukey’s HSD test (α = 0.05). The setting times ranged from 2.4 to 4.6 min for RelyX and from 4.9 to 6.0 min for Panavia. The biaxial flexure strength ranged from 76.5 to 109.7 MPa for RelyX and from 73.3 to 108.2 MPa for Panavia. Vickers hardness values ranged from 41.6 to 58.6 for RelyX and 27.2 to 33.6 for Panavia. The addition of 0.5 and 1 wt% GA to improve durability of resin-dentin bonds had no adverse effects on setting time, whereas the biaxial flexure strength and Vickers hardness values for the tested materials were significantly reduced.