Use of a new skin colour measurement method for the investigation of relationship between skin and tooth colour.

PURPOSE: There is conflicting information about the relationship between tooth color and skin color in the literature. The aim of the present study was evaluation of the correlation between L, a, b values of skin and tooth shade using a new skin color measurement method. MATERIALS AND METHODS: CIELab values of teeth were obtained through measurements from the middle third of the labial surfaces on central incisors of individuals using a clinical spectrophotometer. CIELab values of the skin were measured through facial images using a software which was manufactured for present study. A statistical analysis program (SAS 9.4) was used for the analysis of the data. Kolmogorov-Smirnow test, t-test, and multivariate regression analysis were used to evaluate the data (α=0.05). RESULTS: Correlations between variables revealed that while the lowest and statistically insignificant correlations were observed with a* values of the skin, significant correlations did not exceed moderate level (p < .05). When considering regression analysis results, b* values of the skin had a statistically significant effect in describing b* values of the tooth, while L* and a* values of the skin were observed to be insufficient in describing L* and a* values of the teeth. CONCLUSION: Results of this study suggest that different significant correlations were observed between the skin and tooth color for different L*, a*, and b parameters (p <0.05 and p <0.01). The results indicated that skin color can be used for tooth color selection in case of loss of natural teeth or when discoloration is present on existing teeth.

Oral parafunctions, personality traits, anxiety and their association with signs and symptoms of temporomandibular disorders in the adolescents.

OBJECTIVES: To investigate the association between oral parafunctions, personality traits, anxiety and signs and symptoms of temporomandibular disorders in the adolescents. METHODS: Two hundred and seventy adolescents were examined clinically for the signs and symptoms of temporomandibular disorders. Participants completed questionnaires about demographic variables, medical history, symptoms of temporomandibular disorders, parafunctional oral habits, Minnesota Multibasic Personality Inventory, and Spielberger State-Trait Anxiety Inventory. RESULTS: Logistic regression analyses revealed that bruxism was associated with joint tenderness (Odds ratio (OR)=6.38, p < 0.01), joint noises (OR=6.02, p < 0.01) and masticatory muscle tenderness (OR=4.19, p < 0.05) to palpation. State anxiety showed increased risk of joint tenderness (OR=2.47, p < 0.05) and muscle tenderness (OR=3.25, p < 0.05) to palpation. CONCLUSION: Within the limitations of this study, it was concluded that oral parafunctions, especially bruxism, state anxiety, depression and hysteria were associated with signs and symptoms of temporomandibular disorders in adolescents.

Effect of heat polymerization conditions and microwave on the flexural strength of polymethyl methacrylate.

OBJECTIVE: The objective of this study is the effect of different heat polymerization conditions on the strength of polymethyl methacrylate (PMMA) resin base is unknown. Distinguishing one method that provides improved mechanical properties may be beneficial to the clinical success of complete and partial dentures and overdentures. The purpose of this study was to evaluate the effect of different polymerization methods on the flexural strength of a dental PMMA resin. MATERIALS AND METHODS: Forty PMMA specimens (64 mm × 10 mm × 4 mm) were prepared with 4 different polymerization methods (n = 10); heat polymerization at 74°C for 9 h, at 100°C for 40 min, and with 620 kPa pressure at 100°C for 20 min. The remaining group of specimens was microwave polymerized at 180 W for 6 min. All specimens were thermocycled at 5°C and 55°C for 5000 times. Three-point flexure test was used to measure the flexural strength of specimens. One-way ANOVA and Tukey Honestly Significant Difference were applied to analyze the differences in flexural strengths (α = 0.05). RESULTS: The flexural strength of heat-polymerized groups was similar. The flexural strength of microwave polymerized group was significantly different and lower than the other groups (P < 0.05). CONCLUSION: Polymerizing conventional heat-polymerizing PMMA resin with microwave energy resulted in a significant decrease in flexural strength. The results of this study suggest that clinicians may benefit from using heat polymerization when processing PMMA denture bases instead of microvawe polymerization when tested brand is used.

Surface roughness and adaptation of different materials to secure implant attachment housings.

STATEMENT OF PROBLEM: Various materials are available to secure implant attachment housings in overdentures. Surface roughness and the adaptation of these materials to the denture base and the housings may increase the microcracks and bacterial adhesion at the interfaces in the long term. The surface characteristics of the interface between the denture base orientation material and the attachment housing have not been extensively studied. PURPOSE: The purpose of this in vitro study was to evaluate the surface roughness and the adaptation of 5 different housing orientation materials to the housings and the denture base. MATERIAL AND METHODS: Fifty-five poly(methyl methacrylate) (PMMA) specimens (15 mm in diameter and 4 mm in height) were prepared with a clearance inside to allow the insertion of overdenture housings. Five different materials were used for housing orientation (Quick Up, Ufi Gel Hard, Tokuyama Rebase II Fast, Meliodent, and Paladent). The specimens were thermocycled 5000 times between 5°C and 55°C. The surface roughness (Ra values) of the specimens was measured with a noncontact profilometer. Scanning electron images were made in order to inspect the PMMA-orientation material-housing interfaces. The Kruskal-Wallis test was used to investigate the differences between the surface roughness values of the orientation materials, and the Iman-Conover test was used for pairwise comparisons (α=.05). RESULTS: The surface roughness values significantly differed between Quick up and Ufi Gel orientation materials only, and Quick up had smaller surface roughness values than Ufi Gel (P=.009). Microcracks were observed among the groups only at the junction of the orientation material and the housing after thermocycling. CONCLUSIONS: Ufi Gel Hard showed the roughest surfaces around the overdenture attachment housings. The adaptation between the orientation material and the housing may deteriorate, and increased surface roughness and microcrack formation may be seen around the housings.

Effect of denture cleansing solutions on different retentive attachments.

STATEMENT OF PROBLEM: Various Locator abutments and attachments are available commercially for use in overdenture patients. Patients are advised to use cleansing agents to keep their overdentures clean. The effect of different cleansing agents on attachments with different retention is not known. PURPOSE: The purpose of this in vitro study was to evaluate the retention of 3 Locator abutment attachments after they were soaked in 3 different cleansing solutions. MATERIAL AND METHODS: An implant analog with a diameter of 4.1 mm was embedded into acrylic resin, and 1 Locator abutment was placed onto the analog. Seven specimens of clear, pink, and blue Locator attachments (n=7) were soaked in 3 different denture-cleansing solutions (NaOCl, sodium perborate, sodium perborate-sodium bicarbonate) for a time simulating 6 months of clinical use. The control group was soaked in tap water. A testing machine was used to test the attachments' retention. The retention of the attachments after they were soaked in denture cleansers was compared among the groups with repeated-measures analysis of variance followed by the Tukey HSD test (α=.05). RESULTS: The retention of the clear attachments was significantly less after they had been soaked in sodium bicarbonate-containing denture cleanser (P=.001). The retention of the pink Locator attachments was no different after they had been soaked in the different solutions, and the retention of the blue Locator attachments decreased significantly after they had been soaked in the NaOCl and sodium bicarbonate cleansing agents (P=.002). CONCLUSIONS: Attachments of different colors and retention were affected differently by cleansing agents.

Silver nanoparticle incorporation effect on mechanical and thermal properties of denture base acrylic resins.

OBJECTIVE: The aim of the present study was to evaluate the mechanical and thermal characteristics of two denture base acrylic resins containing silver nanoparticles (AgNPs). MATERIAL AND METHODS: Two different acrylic denture base resins (heat-polymerized and microwave polymerized) containing 0.3, 0.8 and 1.6 wt% AgNPs were evaluated for flexural strength, elastic modulus and impact strength. The glass transition temperature (Tg) and relative heat capacity (Cp) of the samples were determined from the Differential Scanning Calorimetry (DSC) results. For statistical analysis, two-way ANOVA and Tukey-HSD tests were performed. RESULTS: Addition of 0.8% and 1.6% AgNPs in microwave-polymerized resin significantly decreased the transverse strength and elastic modulus. In terms of impact strength, the addition of AgNPs has no effect on both resin groups. Glass transition temperature (Tg) was decreased with the addition of AgNPs for both denture base resins. CONCLUSIONS: The incorporation of AgNPs, generally used for antimicrobial efficiency, affected the transverse strength of the denture base acrylic resins depending on the concentration of nanoparticles. Tg was decreased with the addition of AgNPs for both denture base resins.

Corrosion resistance assessment of Co-Cr alloy frameworks fabricated by CAD/CAM milling, laser sintering, and casting methods.

STATEMENT OF PROBLEM: The effects of fabrication methods on the corrosion resistance of frameworks produced with Co-Cr alloys are not clear. PURPOSE: The purpose of this in vitro study was to evaluate the electrochemical corrosion resistance of Co-Cr alloy specimens that were fabricated by conventional casting, milling, and laser sintering. MATERIAL AND METHODS: The specimens fabricated with 3 different methods were investigated by potentiodynamic tests and electrochemical impedance spectroscopy in an artificial saliva. Ions released into the artificial saliva were estimated with inductively coupled plasma-mass spectrometry, and the results were statistically analyzed. The specimen surfaces were investigated with scanning electron microscopy before and after the tests. RESULTS: In terms of corrosion current and Rct properties, statistically significant differences were found both among the means of the methods and among the means of the material groups (P<.05). With regard to ions released, a statistically significant difference was found among the material groups (P<.05); however, no difference was found among the methods. Scanning electron microscopic imaging revealed that the specimens produced by conventional casting were affected to a greater extent by etching and electrochemical corrosion than those produced by milling and laser sintering. CONCLUSIONS: The corrosion resistance of a Co-Cr alloy specimens fabricated by milling or laser sintering was greater than that of the conventionally cast alloy specimens. The Co-Cr specimens produced by the same method also differed from one another in terms of corrosion resistance. These differences may be related to the variations in the alloy compositions.

Generalized Aggressive Periodontitis in a Patient With Nephrotic Syndrome Associated With Primary Renal Amyloidosis: A Case Report.

INTRODUCTION: Renal amyloidosis may lead to renal disease, and then nephrotic syndrome may develop. To the best of the authors' knowledge, this is the first case report in which a patient presents with generalized aggressive periodontitis (GAgP) and nephrotic syndrome in conjunction with renal amyloidosis. CASE PRESENTATION: An 18-year-old male presented to the periodontology department for generalized gingival recessions. He was diagnosed as having primary renal amyloidosis by his physician. The patient presented with severe gingival inflammation and alveolar bone loss. Biochemical tests were within normal limits except for serum albumin level. No amyloid deposition was found in a gingival biopsy, and the patient was diagnosed as having GAgP. Non-surgical periodontal treatment, in combination with antibiotic treatment, was performed. After 3 years, his systemic and periodontal conditions showed deterioration. CONCLUSIONS: The effects of systemic factors related to nephrotic syndrome in conjunction with renal amyloidosis and deterioration in oral hygiene may play a significant role in the progression of periodontal disease. Even if there is no amyloid deposition in periodontal tissues, clinicians should consider that nephrotic syndrome associated with systemic amyloidosis may provide an important contribution to the periodontal breakdown by the modifying conditions that affect the host response to the accumulation of dental biofilm.