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The major drawback of cement-retained restorations is the extrusion of the excess cement into the peri-implant sulcus, with subsequent complications. Insufficient removal of the excess cement may initiate a local inflammatory process, which may lead to implant failure. This article presents a method of controlling cement flow on implant abutments, minimizing the excess cement around implant-retained restorations.
Cementation*

Cobalt-Chromium (Co-Cr) alloys are classified as predominantly base-metal alloys and are widely known for their biomedical applications in the orthopedic and dental fields. In dentistry, Co-Cr alloys are commonly used for the fabrication of metallic frameworks of removable partial dentures and recently have been used as metallic substructures for the fabrication of porcelain-fused-to-metal restorations and implant frameworks. The increased worldwide interest in utilizing Co-Cr alloys for dental applications is related to their low cost and adequate physico-mechanical properties. Additionally, among base-metal alloys, Co-Cr alloys are used more frequently in many countries to replace Nickel-Chromium (Ni-Cr) alloys. This is mainly due to the increased concern regarding the toxic effects of Ni on the human body when alloys containing Ni are exposed to the oral cavity. This review article describes dental applications, metallurgical characterization, and physico-mechanical properties of Co-Cr alloys and also addresses their clinical and laboratory behavior in relation to those properties.
Alloys ; Dental Alloys* ; Dentistry ; Denture, Partial, Removable ; Human Body ; Mouth ; Orthopedics ; Prosthodontics*

PURPOSE: The purpose of this study was to evaluate the patients' knowledge on dental implants in a Turkish subpopulation. MATERIALS AND METHODS: Five hundred twenty seven Turkish adults referred to Yeditepe University Faculty of Dentistry, Istanbul, Turkey, were presented with a questionnaire including 20 questions regarding the level of information and awareness about the dental implants. The data were collected and statistical analyses were performed with Chi square test to compare the descriptive data. RESULTS: Among 527 subjects, 54% were female and 46% were male with a mean age of 42.2 years. The rate of patients' implant awareness was 27.7%. When the patients were questioned about the treatment options for rehabilitation of tooth missing, 60.9% of patients were informed about fixed partial denture, followed by conventional complete denture (32.5%) and removable partial denture (24.9%). Six percent reported that they were very well informed about the dental implants whereas 48.2% were poorly informed. The information sources of the implants were from the dentist (44.5%), printed media (31.6%) and friends and acquaintances (17.3%), respectively. Sixteen percent of the population believed that their implants would last forever. CONCLUSION: The dentists should give more detailed information to the patients about dental implants and tooth-supported fixed partial dentures in the future.
Adult ; Dental Implants* ; Dentistry ; Dentists ; Denture, Complete ; Denture, Partial, Fixed ; Denture, Partial, Removable ; Female ; Friends ; Humans ; Male ; Mass Media ; Rehabilitation ; Tooth ; Turkey

PURPOSE: This study was conducted to evaluate the influence of the implant-abutment connection design and diameter on the screw joint stability. MATERIALS AND METHODS: Regular and wide-diameter implant systems with three different joint connection designs: an external butt joint, a one-stage internal cone, and a two-stage internal cone were divided into seven groups (n=5, in each group). The initial removal torque values of the abutment screw were measured with a digital torque gauge. The postload removal torque values were measured after 100,000 cycles of a 150 N and a 10 Hz cyclic load had been applied. Subsequently, the rates of the initial and postload removal torque losses were calculated to evaluate the effect of the joint connection design and diameter on the screw joint stability. Each group was compared using Kruskal-Wallis test and Mann-Whitney U test as post-hoc test (alpha=0.05). RESULTS: The postload removal torque value was high in the following order with regard to magnitude: two-stage internal cone, one-stage internal cone, and external butt joint systems. In the regular-diameter group, the external butt joint and one-stage internal cone systems showed lower postload removal torque loss rates than the two-stage internal cone system. In the wide-diameter group, the external butt joint system showed a lower loss rate than the one-stage internal cone and two-stage internal cone systems. In the two-stage internal cone system, the wide-diameter group showed a significantly lower loss rate than the regular-diameter group (P<.05). CONCLUSION: The results of this study showed that the external butt joint was more advantageous than the internal cone in terms of the postload removal torque loss. For the difference in the implant diameter, a wide diameter was more advantageous in terms of the torque loss rate.
Joints* ; Torque

PURPOSE: The purpose of this study was to investigate the bonding properties of denture bases to silicone-based soft denture liners immersed in isobutyl methacrylate (iBMA) and 2-hydroxyethyl methacrylate (HEMA) for various lengths of time. MATERIALS AND METHODS: Polymethyl methacrylate (PMMA) test specimens were fabricated (75 mm in length, 12 mm in diameter at the thickest section, and 7 mm at the thinnest section) and then randomly assigned to five groups (n=15); untreated (Group 1), resilient liner immersed in iBMA for 1 minute (Group 2), resilient liner immersed in iBMA for 3 minutes (Group 3), resilient liner immersed in HEMA for 1 minute (Group 4), and resilient liner immersed in HEMA for 3 minutes (Group 5). The resilient liner specimens were processed between 2 PMMA blocks. Bonding strength of the liners to PMMA was compared by tensile test with a universal testing machine at a crosshead speed of 5 mm/min. Data were evaluated by 1-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests (alpha=0.05). RESULTS: The highest mean value of force was observed in Group 3 specimens. The differences between groups were statistically significant (P<.05), except between Group 1 and Group 4 (P=.063). CONCLUSION: Immersion of silicone-based soft denture liners in iBMA for 3 minutes doubled the tensile bond strength between the silicone soft liner and PMMA denture base materials compared to the control group.
Denture Bases* ; Denture Liners* ; Immersion ; Polymethyl Methacrylate ; Silicones

PURPOSE: The aim of this in vitro study was to evaluate the effect of aging on the tear strength and cytotoxicity of four soft denture lining materials. MATERIALS AND METHODS: Four commonly used soft denture lining materials, (Coe-Comfort(TM) GC America Inc., Alsip, IL, USA; Coe-Soft(TM) GC America Inc., Alsip, IL, USA; Visco-gel Dentsply Caulk Milford, DE, USA; and Sofreliner Tough M Tokuyama Dental Corporation Tokyo, Japan) were selected. Sixty trouser-leg designed specimens per lining material were fabricated using a stainless steel mold for tear strength testing. The specimens were divided into non-thermocycling and 1000-, and 3000- thermocycling groups. For the cytotoxicity test, twenty-four disk shaped specimens per material were fabricated using a stainless steel mold. The specimens were soaked in normal saline solution for 24 h, 48 h and 72 h. Cytotoxicity was measured by XTT assay in L929 mouse fibroblasts. Data were analyzed by two way analysis of variance and Dunnett's test (P<.05). RESULTS: Before thermocycling, Sofreliner Tough M (10.36 +/- 1.00 N) had the highest tear strength value while Coe-Comfort(TM) (0.46 +/- 0.10 N) had the lowest. After 3000 cycles, Sofreliner Tough M (9.65 +/- 1.66 N) presented the highest value and Coe-Comfort(TM) (0.42 +/- 0.08 N) the lowest. Sofreliner Tough M, in all incubation periods was the least toxic with significant differences compared to all other materials (P<.05). Coe-Comfort(TM), Coe-Soft(TM), and Sofreliner Tough M did not show any significant differences within their material group for all incubation periods. CONCLUSION: This in vitro study revealed that aging can affect both the tear strength and cytotoxicity of soft denture materials depending on the composition.
Aging* ; Americas ; Animals ; Dentures* ; Fibroblasts ; Fungi ; Mice ; Sodium Chloride ; Stainless Steel

PURPOSE: The purpose of this study was to analyze the effect of denture cleansers on Candida albicans biofilm formation over resilient liners and to evaluate compatibility between resilient liners and denture cleansers. MATERIALS AND METHODS: Acrylic resin (Lucitone 199(R)) and 3 resilient liners (COE-SOFT(TM), GC RELINE(TM) and SOFRELINER TOUGH TOUGH(R)) were incubated in denture cleansers (Polident(R) and Cleadent(R)) for 8 hours a day and in unstimulated saliva for 16 hours a day (n=25/gp) for 60 days. Two-way and three-way repeated measures ANOVA were performed to compare the surface roughness (Ra), pH and C. albicans binding level by radioisotope (alpha=0.05). The statistical significance of the relation between Ra and adhesion was evaluated by correlation analysis. RESULTS: The degree of Ra was significantly decreased in the following order: COE-SOFT(TM), acrylic resin, GC RELINE(TM) and SOFRELINER TOUGH(R). The immersion in denture cleansers significantly increased Ra of resilient liners, except for SOFRELINER TOUGH(R) in Cleadent(R). No significant differences in pH curves were observed among groups immersed in distilled water and denture cleansers. The binding levels of C. albicans were significantly decreased in the following order: COE-SOFT(TM), GC RELINE(TM), SOFRELINER TOUGH(R), and acrylic resin. The immersion in Cleadent(R) seemed to decrease C. albicans binding level on GC RELINE(TM) and SOFRELINER TOUGH(R). CONCLUSION: Based on the C. albicans binding levels results, it is not recommended to immerse COE-SOFT(TM) in denture cleansers, and GC RELINE(TM) and SOFRELINER TOUGH(R) should be immersed in Cleadent(R).
Biofilms* ; Candida albicans* ; Denture Cleansers* ; Hydrogen-Ion Concentration ; Immersion ; Saliva ; Water

PURPOSE: The occlusal splint has been used for many years as an effective treatment of sleep bruxism. Several methods have been used to evaluate efficiency of the occlusal splints. However, the effect of the occlusal splints on occlusal force has not been clarified sufficiently. The purpose of this study was to evaluate the effect of occlusal splints on maximum occlusal force in patients with sleep bruxism and compare two type of splints that are Bruxogard-soft splint and canine protected hard stabilization splint. MATERIALS AND METHODS: Twelve students with sleep bruxism were participated in the present study. All participants used two different occlusal splints during sleep for 6 weeks. Maximum occlusal force was measured with two miniature strain-gage transducers before, 3 and 6 weeks after insertion of occlusal splints. Clinical examination of temporomandibular disorders was performed for all individuals according to the Craniomandibular Index (CMI) before and 6 weeks after the insertion of splints. The changes in mean occlusal force before, 3 and 6 weeks after insertion of both splints were analysed with paired sample t-test. The Wilcoxon test was used for the comparison of the CMI values before and 6 weeks after the insertion of splints. RESULTS: Participants using stabilization splints showed no statistically significant changes in occlusal force before, 3, and 6 weeks after insertion of splint (P>.05) and participants using Bruxogard-soft splint had statistically significant decreased occlusal force 6 weeks after insertion of splint (P<.05). There was statistically significant improvement in the CMI value of the participants in both of the splint groups (P<.05). CONCLUSION: Participants who used Bruxogard-soft splint showed decreases in occlusal force 6 weeks after insertion of splint. The use of both splints led to a significant reduction in the clinical symptoms.
Bite Force* ; Humans ; Occlusal Splints* ; Pilot Projects* ; Sleep Bruxism* ; Splints ; Temporomandibular Joint Disorders ; Transducers

PURPOSE: This study was performed to characterize the effects of zirconia coated with calcium phosphate and hydroxyapatite compared to smooth zirconia after bone marrow-derived osteoblast culture. MATERIALS AND METHODS: Bone marrow-derived osteoblasts were cultured on (1) smooth zirconia, (2) zirconia coated with calcium phosphate (CaP), and (3) zirconia coated with hydroxyapatite (HA). The tetrazolium-based colorimetric assay (MTT test) was used for cell proliferation evaluation. Scanning electron microscopy (SEM) and alkaline phosphatase (ALP) activity was measured to evaluate the cellular morphology and differentiation rate. X-ray photoelectron spectroscopy (XPS) was employed for the analysis of surface chemistry. The genetic expression of the osteoblasts and dissolution behavior of the coatings were observed. Assessment of the significance level of the differences between the groups was done with analysis of variance (ANOVA). RESULTS: From the MTT assay, no significant difference between smooth and surface coated zirconia was found (P>.05). From the SEM image, cells on all three groups of discs were sporadically triangular or spread out in shape with formation of filopodia. From the ALP activity assay, the optical density of osteoblasts on smooth zirconia discs was higher than that on surface treated zirconia discs (P>.05). Most of the genes related to cell adhesion showed similar expression level between smooth and surface treated zirconia. The dissolution rate was higher with CaP than HA coating. CONCLUSION: The attachment and growth behavior of bone-marrow-derived osteoblasts cultured on smooth surface coated zirconia showed comparable results. However, the HA coating showed more time-dependent stability compared to the CaP coating.
Alkaline Phosphatase ; Calcium ; Cell Adhesion ; Cell Proliferation ; Chemistry ; Durapatite ; Microscopy, Electron, Scanning ; Osteoblasts* ; Photoelectron Spectroscopy ; Pseudopodia