The effects of different surface treatments applied to milled PMMA denture base material on repair bond strength.

The high cost of CAD/CAM systems and materials is a severe economic burden. Therefore, repair of CAD/CAM PMMA, selecting appropriate repair materials, and surface modifications are clinically important. This study aims to evaluate the shear bond strength of PMMA repair materials after various surface treatments on CAD/CAM PMMA denture base material. For this purpose, a total of 480 CAD/CAM PMMA denture base test specimens were manufactured. Then all test specimens were divided into 6 groups, and different surface treatments were applied. Group A: sandblasting, Group B: 4% hydro fluoric acid, Group C: tungsten carbide bur, Group D: dichloromethane + methyl methacrylate mixture, Group E: dichloromethane and methyl methacrylate, Group F: no surface treatment. Each group is then divided into 4 different subcategories; repair processes were performed using; heat-cured acrylic resin (n:20), auto-polymerized acrylic resin (n:20), gingiva composite (n:20), and CAD/CAM PMMA tooth material (n:20). After repairs, thermal aging was applied to half of the test specimens in each subcategory. The shear bond strength value was measured with a universal test device. Sandblasting group showed the highest surface roughness value in all test specimens (p < 0.001). Heat-cured acrylic resin with sandblasting exhibited the highest bond strength, while the untreated gingiva composite resin exhibited the lowest value. Thermal aging decreased bond strength in all repair materials (p < 0.001). Among the surface treatment groups, sandblasting with Al2O3 particles exhibited the highest surface roughness value and repair bond strength. The application of organic solvents to the surface increased the surface roughness and repair bond strength. Applying dichloromethane and methyl methacrylate monomer separately is more effective than applying it as a mixture. The ideal bonding among repair materials was obtained with heat-cured acrylic resin.

Surface treatment effects on bond strength of CAD/CAM fabricated posts to root canal dentin.

PURPOSE: 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. METHODS: 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. RESULTS: Micropush-out bond strength of posts to dentin was significantly affected by the type of post material (P< 0.05), but not by the surface treatment (P= 0.397). CLINICAL SIGNIFICANCE: Posts manufactured by CAD/CAM could be suitable options for restoration of severely affected endodontically-treated teeth.

Light Transmission of Novel CAD/CAM Materials and Their Influence on the Degree of Conversion of a Dual-curing Resin Cement.

PURPOSE: To evaluate the light transmission characteristics of different types, shades, and thicknesses of novel CAD/CAM materials and their effect on the degree of conversion (DC) of a dual-curing resin cement. MATERIALS AND METHODS: Square specimens (12 × 12 mm2) of three CAD/CAM materials - GC Cerasmart, Lava Ultimate, Vita Enamic - of different thicknesses (1.00, 1.50, and 2.00 mm, n = 5 per thickness) were irradiated with an LED unit. The amount of transmitted light was quantified. Thereafter, the DC% of the dual-curing resin cement (RelyX Ultimate) was recorded after 15 min using Fourier transform infrared spectroscopy. Statistical analysis was performed using two-way ANOVA followed by the Tukey's HSD post-hoc test at a significance level of p < 0.05. Regression analysis was performed to investigate the correlation between the DC and radiant energy, and the DC and thickness. RESULTS: Although the type and shade of CAD/CAM material significantly affect transmitted light irradiation (p < 0.0001), degrees of conversion are similar when the CAD/CAM material or material shade were taken into consideration (p > 0.05). Conversely, material thickness significantly affected light transmission (p < 0.0001) and DC (p < 0.0001). Multiple effects of material, shade, and thickness did not significantly affect the evaluated parameters (p = 0.638 for light irradiation; p = 0.637 for DC). Linear regression analysis showed a correlation between delivered energy and DC% results of the Vita Enamic (R²â€¯= 0.4169, p < 0.0001). CONCLUSION: Reduced light transmission in 2-mm-thick specimens of all CAD/CAM materials indicates that proper curing of the cement beneath CAD/CAM materials should be ensured.

Implant-Supported Prosthetic Rehabilitation of a Patient with Localized Severe Attrition: A Clinical Report.

Patients usually adapt to their existing occlusal vertical dimension (OVD). It is essential to resolve each of the problems associated with decreased vertical dimension as a result of attrition. This report describes the multidisciplinary dental treatment of a 40-year-old male patient who had severe tooth wear, resulting in reduced vertical dimension. After clinical evaluations, extraoral examination showed a reduction of the lower facial height, drooping, and overclosed commissures. Ten dental implants were placed into the maxillary and mandibular alveolar processes. During the osseointegration period, an interim removable partial denture was made at increased OVD to use in the first stage of rehabilitation. It was used for 3 months as a guide for preparing the definitive restorations. The patient's adaptation to the increased OVD was evaluated. During this period, he was asymptomatic. Following the evaluation period, the provisional fixed restoration was used for 3 months. Then, full-mouth definitive prostheses supported by a combination of implants and teeth were fabricated to upper and lower jaws. Osseointegration of the implants, peri-implant mucosa health, prosthesis function, and esthetics were assessed after 1 week and 1, 3, and 6 months. After 3 years of follow-up, no functional or esthetic difficulties with the implants and restorations were noted.

Full-mouth rehabilitation of a patient with severe deep bite: a clinical report.

Increasing the vertical dimension is essential to resolving problems associated with deep bite. Restorative dentistry, orthodontia, and oral surgery are the three disciplines that can help to gain the vertical dimension necessary in these patients. This clinical report presents the results of increasing vertical dimension with a full-mouth restorative treatment procedure for a 40-year-old male patient who exhibited severe deep bite. After clinical evaluation, extraoral examination showed a reduction of the lower facial height and protuberant lips, wrinkles, drooping, and overclosed commissures. In addition, intraoral examination showed a severe anterior deep-bite articulation, and upper incisors were in contact with the lower incisor labial tissue. A removable partial denture was made at increased occlusal vertical dimension (OVD) to use in the first stage of rehabilitation. Diagnostic wax-up was performed at the increased vertical dimension. Then, provisional crowns were fabricated according to this increased vertical dimension. Interim prostheses were used for 3 months as a guide for preparing the definitive restorations. The adaptation of the patient to the increased OVD was evaluated. During this period, he was asymptomatic. Following the evaluation period, definitive restorations were completed, and routine clinical assessments were made after 1 week, 1 month, 3 months, and 6 months, then after 1 and 2 years with visual and radiographic examinations.

Functional and esthetic rehabilitation of a patient with amelogenesis imperfecta.

Amelogenesis imperfecta (AI) is a hereditary disorder that causes developmental alterations in the structure of enamel. In addition, tooth sensitivity, missing or impacted teeth, taurodontism, altered dental esthetics and anterior open bite can also be associated with AI. This clinical report presents the diagnosis, treatment planning and prosthetic rehabilitation of a 19-year-old female patient with AI associated with a group of dental anomalies. Following clinical and radiographic examination, histologic evaluation of the teeth confirmed the diagnosis of rough pattern hypoplastic AI. The patient was rehabilitated with full-mouth zirconium oxide ceramic fixed bridges. Adaptation of the temporomandibular joints and masticatory muscles to the bridges was carefully observed over 3 years. At the end of this follow-up period, the patient was satisfied with the esthetics, function and phonation of her prostheses.

The effect of post length and core material on root fracture with respect to different post materials.

OBJECTIVE: The aim of this study was to evaluate the effect of different core materials and post length on the fracture strength of different posts (CAD/CAM zirconia post (ZR post)) and an individually formed glass fiber reinforced composite post (FRC post). MATERIALS AND METHODS: One hundred maxillary central incisors received endodontic treatment and were divided into two groups according to the post length: (1) 10 mm in length and (2) 15 mm in length (n = 50/per group). Then the specimens were randomly assigned into five sub-groups (n = 10/per group) as follows: One-piece milled zirconia post and core (group Zr), zirconia post with resin core (Biscore, Bisco) (group Zr/R), zirconia post with resin composite core (Admira, Voco) (group Zr/RC), FRC post with resin core (group F/R) and FRC post with resin composite core (group F/RC). The posts were cemented with a self-adhesive luting agent according to the manufacturer's instructions by using endo tips and light-cured for 40 s using a halogen light curing unit. Metal crowns were made for each specimen, cemented and loaded to failure. Fracture loads (N) and modes of failure were recorded. The data were analyzed using three-way analysis of variance (ANOVA) followed by Tukey's post-hoc test (p < 0.001). RESULTS: Fracture strength of roots was significantly affected by the type of post material (p < 0.05) and post length (p < 0.05), but not by the type of core materials used (p = 0.078). CONCLUSION: Longer zirconia posts with zirconia- or resin-based cores can be recommended as an alternative to FRC posts with resin-based cores. The fracture patterns observed in teeth restored with fiber posts were more favorable than teeth restored with zirconia posts. Clinical significance. A higher restoring success rate can be achieved by fiber posts rather than zirconia posts, since the failure mode for these posts would be restorable. Additionally, post length is a more critical factor in teeth restored with one-piece milled zirconia posts than in those restored with fiber posts.

Bond strength of self-adhesive resin cements to dentin after antibacterial and chelating solution treatment.

OBJECTIVE: The aim of this study was to evaluate the effect of tetracycline HCl, 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) and chlorhexidine digluconate (CHX) on micro push-out (µ-PO) bond strengths of two self-adhesive resin cements on dentin. MATERIALS AND METHODS: Sixty discs of 1.25 mm thickness (middle dentin) were prepared from human molars perpendicular to the tooth axis. Two standardized occlusal cavities of 2.20 mm occlusal diameter and 1.25 mm cervical diameter were prepared in each disc. The cavities were divided into three groups in accordance with the surface treatment (50 mg/ml tetracycline HCl, 18% HEBP and 2% CHX solutions). Following the treatment of the discs for 5 min, cavities were filled with two different self-adhesive resin cements (Clearfil(™) SA Cement and RelyX(™) Unicem). After light polymerization of cements, µ-PO bond strength tests were performed. Failure modes were examined and dentin morphologic assessments were done. Statistical significance was determined by a multivariate analysis of variance (MANOVA) followed by Tukey's post-hoc test (p < 0.05). Additionally, a paired-samples T-test was used to compare the µ-PO bond strengths of self-adhesive resin cements (p < 0.05). RESULTS: Paired-samples T-test revealed that there was no significant difference between tested self-adhesive resin cements (p = 0.612). No significant two-factor interaction was observed between Clearfil(™) SA Cement and chemical agents (p = 0.457). Similarly, tetracycline HCl and CHX did not have a significant effect on the bond strength of RelyX(™) Unicem (p > 0.05). However, HEBP significantly decreased the bond strength of RelyX(™) Unicem when compared to the control (p < 0.05). Conclusion. The tetracycline HCl and CHX solutions do not have beneficial effects on µ-PO bond strengths of self-adhesive resin cements. Additionally, the results of this study do not justify the use of self-adhesive resin cements, following HEBP treatment of dentin. CLINICAL SIGNIFICANCE: The application of topical HEBP solution treatment to dentin could have adverse effects on the µ-PO bond strengths of RelyX(™) Unicem.

Influence of cement thickness on the bond strength of tooth-colored posts to root dentin after thermal cycling.

OBJECTIVE: The purpose of this study was to evaluate the effect of different resin cement thickness on the push-out bond strength of different posts (CAD/CAM zirconia post (ZR post)) and an individually formed glass fiber reinforced composite post (IPN post) prior to and after thermal cycling (TC). METHODS: Post spaces with a height of 9 mm and a diameter of 1.5 mm were drilled in 80 mandibular premolar teeth. Two groups (n = 40) were formed according to the posts used (IPN posts or ZR posts). Then the specimens were randomly assigned into two sub-groups according to the post diameter: (1) 1.5 mm in diameter and (2) 1.2 mm in diameter (n = 20/per group). All posts were luted with a self-adhesive luting agent according to the manufacturer's instructions by using endo tips. Half of the samples (n = 10) were submitted to thermal cycling (5000 cycles, 5-55 °C). Thereafter, four 2-mm thick horizontal sections were obtained and subjected to push-out test. Failure modes were assessed quantitatively and morphologically. The data were statistically analyzed with a three-way analysis of variance (ANOVA) (p < 0.05). Statistical differences in failure modes were investigated by chi-square tests at a significance level of p < 0.05. RESULT: Push-out bond strengths were significantly influenced both by the post diameter and thermal cycling. Larger (1.5 mm) diameter post results were statistically higher than 1.2 mm results (p < 0.05). Moreover, TC significantly increased the bond strength results (p < 0.05). There was no significant difference between ZR and IPN posts (p = 0.219). CONCLUSION: The bond strengths of ZR and IPN posts were significantly decreased when the resin cement layer was thick. In addition, thermal cycling drastically influenced bond strengths of the tested post materials. CLINICAL SIGNIFICANCE: The fit between tooth-colored endodontic posts and post spaces should be as tight as possible.

Micro-shear bond strength of resin cement to dentin after application of desensitizing toothpastes.

OBJECTIVES: The aim of the study was to evaluate the effect of three desensitizing toothpastes on bonding of resin cements to dentin. MATERIALS AND METHODS: The occlusal surfaces of 72 maxillary third molars were ground to obtain flat dentin surfaces and then divided into three groups according to three desensitizing toothpastes used: Sensodyne Rapid Relief (GlaxoSmithKline, SmithKline Beecham Ltd., Slough, UK), Signal Sensitive Expert (Unilever Sanayi ve Ticaret Türk A.S., Ümraniye, Istanbul, Turkey) and Colgate Sensitive Pro-Relief (Colgate Palmolive, New York, NY). Following bonding of the resin cement (Clearfil™ SA Cement, Kuraray Co, Osaka, Japan) to dentin, the specimens were light cured for 40 s with a LED (Elipar S10, 3M Espe, St. Paul, MN). The strength measurements were accomplished with a micro-shear testing machine (Bisco, Schaumburg, IL) at a cross-head speed of 0.5 mm/min until the failure occurs. Failure modes were examined using a stereomicroscope and scanning electron microscope. The data were analyzed with one-way analysis of variance (ANOVA) and Tukey HSD test (α = 0.05). RESULTS AND CONCLUSION: ANOVA revealed that the application of desensitizing toothpastes had significant effects on bond strength of the resin cement tested to dentin (p < 0.05). Mixed failures were observed in all of the groups. CLINICAL SIGNIFICANCE: The use of a desensitizing toothpaste before cementation might alter the bond strength of adhesively luted restorations.

Light transmittance of zirconia as a function of thickness and microhardness of resin cements under different thicknesses of zirconia.

OBJECTIVE: The objective of this study was to compare microhardness of resin cements under different thicknesses of zirconia and the light transmittance of zirconia as a function of thickness. STUDY DESIGN: A total of 126 disc-shaped specimens (2 mm in height and 5 mm in diameter) were prepared from dual-cured resin cements (RelyX Unicem, Panavia F and Clearfil SA cement). Photoactivation was performed by using quartz tungsten halogen and light emitting diode light curing units under different thicknesses of zirconia. Then the specimens (n=7/per group) were stored in dry conditions in total dark at 37°C for 24 h. The Vicker's hardness test was performed on the resin cement layer with a microhardness tester. Statistical significance was determined using multifactorial analysis of variance (ANOVA) (alpha=.05). Light transmittance of different thicknesses of zirconia (0.3, 0.5 and 0.8 mm) was measured using a hand-held radiometer (Demetron, Kerr). Data were analyzed using one-way ANOVA test (alpha=.05). RESULTS: ANOVA revealed that resin cement and light curing unit had significant effects on microhardness (p < 0.001). Additionally, greater zirconia thickness resulted in lower transmittance. There was no correlation between the amount of light transmitted and microhardness of dual-cured resin cements (r = 0.073, p = 0.295). CONCLUSION: Although different zirconia thicknesses might result in insufficient light transmission, dual-cured resin cements under zirconia restorations could have adequate microhardness.

Effect of surface modification on the bond strength between zirconia and resin cement.

PURPOSE: This study aimed to evaluate the micro push-out (µ-PO) bond strength between zirconia and resin cement after addition of zirconia particles to increase the surface roughness. MATERIALS AND METHODS: Y-TZP zirconia specimens in three experimental groups were subjected to Y-TZP particle deposition via dipping into the milling residue suspension at different times prior to the sintering process. The dipping procedure was repeated twice for each specimen in group B, six times in group C, and ten times in group D. The specimens subjected to airborne-particle abrasion (110 µm Al2 O3, Rocatec Pre) acted as the control group (group A). All of the specimens were then bonded using adhesive resin cement (RelyX Ultimate). A µ-PO test was used to determine the bond strength values. One-way ANOVA at a 5% confidence level was performed for data analysis. Optical microscopy and scanning electron microscopy (SEM) were used to evaluate the failure modes and surface structure. RESULTS: Y-TZP particle deposition did not have a significant effect on the bond strength of the resin cement to zirconia specimens when compared to the control (p = 0.141). Higher bond strength values were observed in groups C and D than in control. The surface layer presented blister-like porosities with openings of various diameters ranging between 2 and 4 µm. CONCLUSION: Y-TZP particle deposition after dipping six and ten times did not improve the mean bond strength statistically but presented surface topography that may be favorable for increased micromechanical retention for adhesive resin cement. CLINICAL SIGNIFICANCE: Y-TZP particle deposition may create a more retentive surface than airborne-particle abrasion for adhesive bonding between zirconia surface and resin cement.

Bond strength of various post-core restorations with different lengths and diameters following cycle loading.

PURPOSE: This in vitro study aims to evaluate the bonding strengths of Polyether ether ketone (PEEK), Polyether ketone (PEKK), Fiber, and Zirconia (ZrO2) post-core restorations with posts in different diameter and length following chewing simulator. MATERIALS AND METHODS: Endodontic treatment was performed on 256 intact maxillary central teeth. The test specimens were prepared in four groups according to the types of materials: Glass fiber post-composite core (FB-n:64), Zirconia post-core (Zr-n:64), PEEK post-core (PE-n:64), and PEKK post-core (PK-n:64). The groups were divided into four subgroups according to diameter and length (n:16): Group 1: 10 mm length 1.75 mm diameter, Group 2: 10 mm length 1.5 mm diameter, Group 3: 7 mm length 1.75 mm diameter, Group 4: 7 mm length 1.5 mm diameter. Custom PEKK, PEEK, Zirconia post-cores, and Zirconia crowns were milled on the CAD/CAM. The post-cores and crowns were cemented to the teeth with dual-cure resin cement. After that, all subgroups were divided into control and cyclic loading groups. During the cycling, the control test group was kept in distilled water at 37±1oC before the push-out test. Half of the specimens were loaded with 250,000 cycles and 50 N with a chewing simulator. All test specimens had 1.5 mm sections taken from their roots. Then, the push-out test was applied to these sections for bond strength. Data were analyzed by Mann-Whitney U test, Shapiro-Wilk, Kruskal-Wallis's test, and Chi-Square. The statistical significance level was determined as 0.05. RESULTS: The bond strength of all test groups decreased after the cycling loading. The bond strength values of zirconia posts showed a statistically significant difference (p < 0.05). The 10 mm length 1.75 mm diameter posts made of Zirconium had the highest bond strength observed in all control and cyclic loading groups of test specimens (9.74 MPa-6.25 MPa). The PEEK test specimens with a 7 mm length and 1.75 mm diameter showed the weakest bond strength in all control and cyclic loading groups (5.44 MPa-3.37 MPa). The average of the cervical region's bond strength values was statistically significantly higher than the apical region (p < 0.05). CONCLUSION: Within the limitations of this study, one-piece custom-milled Zirconia post-cores appear promising, as they perform well under functional forces, especially in the anterior region. In addition, custom-milled PEKK post-cores might be considered a suitable alternative to prefabricated fiber-reinforced posts.

Effects of the substructure thickness, the resin cement color and the finishing procedure on the color and translucency of zirconia-based ceramic restorations.

BACKGROUND: The ability to simulate the natural appearance of teeth in dental restorations is one of the most important factors that make treatment successful. OBJECTIVES: The present study evaluated the effects of the substructure thickness, the resin cement color and the finishing procedure on the color and translucency of bilayer zirconia-based ceramic restorations. MATERIAL AND METHODS: Yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) CAD/CAM blocks (dimensions of 6.0 × 5.5 × 0.4 mm, 6.0 × 5.5 × 0.8 mm, and 6.0 × 5.5 × 1.6 mm) veneered with the fluorapatite-containing ceramics were used. For polishing, the surfaces of half of the test specimens were adjusted with a blue-belted diamond porcelain bur and a white polishing rubber, and the other half were glazed. The test specimens were then cemented with 2 different colors of the same self-adhesive resin cement to the resin composite. A spectrophotometer was used to measure the L*, a*, and b* color attributes of the specimens. Additionally, the ΔE values were calculated to determine color differences between each group and the control. Data was analyzed using the multifactorial repeated-measures analysis of variance (ANOVA) and subgroup analysis (p < 0.005). RESULTS: It was found that the highest substructure thickness resulted in the lowest color change (ΔE = 1.24) (p < 0.005). However, a substructure thickness of 0.8 mm showed less color change (ΔE = 1.39) than the 0.4-mm thickness (ΔE = 3.85) in the translucent resin cement/polished subgroup, as measured against a gray background (p = 0.001). CONCLUSIONS: The most significant factor in masking the abutment color in zirconia-based restorations is the thickness of the substructure. The surface finishing procedure or the resin cement color do not have a primary effect on the color change or translucency.

The Effects of Er,Cr:YSGG laser on shear bond strength of orthodontic lingual brackets to CAD/CAM ceramic systems.

Purpose: The aim of this study is to compare the bond strength of lingual brackets bonded to resin-matrix and lithium disilicate based-ceramic crowns following various surface treatments. Materials and methods: Sixty ceramic crowns (IPS Emax and Cerasmart) were fabricated by CAD/CAM. Er,Cr:YSGG laser, sandblasting with aluminium oxide and hydrofluoric acid treatment effects on ceramics was tested (n=10/group). A light-cure orthodontic adhesive was used to bond lingual brackets to the ceramic surfaces. Bond strengths of the brackets to ceramics were assessed by shear bond test. The remnant adhesive on bracket and ceramic surfaces was inspected with a light microscope and adhesive remnant index scores were recorded. The data were analyzed statistically using the Kruskal-Wallis test followed by the Mann-Whitney U-test. Results: Cerasmart ceramic specimens showed lower shear bond strength values than IPS Emax ceramic specimens (p<0.05). The statistical analysis of the surface treatment groups regarding bond strength were ranked as follows: Laser ≤ Hydrofluoric acid ≤ Sandblasting (p=0.058). While laser-treated Cerasmart ceramic group displayed the lowest SBS (9.39 MPa), hydrofluoric acid-treated IPS Emax group had the highest (16.8 MPa) bond strength value. Conclusion: The use of Er,Cr:YSGG lasers for etching of CAD-CAM ceramics could be a promising alternative to "conventional techniques", to improve bond strength of lingual brackets to IPS Emax and Cerasmart ceramics.

Estimation of the surface gloss of dental nano composites as a function of color measuring geometry.

PURPOSE: To estimate the surface gloss of various dental nano composites by using the correlation between deltaE* specular component excluded (SCE) - specular component included (SCI) and surface roughness (Ra). METHODS: Two brands of commercial and two experimental light-cured resin composites were used. Resin composite discs were prepared 10 mm in diameter and 3 mm in thickness. 56 subgroups (n=5) were designed according to two different curing conditions (hand light curing and additional post-heat curing) and seven different polishing methods (Mylar, 4000-, 2400-, 1200- and 320- SiC paper, rubber-based silicone, three-step polishing kit). deltaE*SCE-SCI and Ra measurements were done. Two specimens in each subgroup were analyzed by SEM. Multifactorial ANOVA and post hoc Tukey test were applied for the evaluation of the deltaE*SCE-SCI and Ra data (P<0.05). Moreover, Spearman's rank correlation test was used to determine the correlation between deltaE*SCE-SCI and Ra results (P<0.01). RESULTS: A strong correlation was found between deltaE*(SCE-SCI) and Ra results indicating the surface gloss of the tested composite resin materials after different curing and surface polishing methods. A three-factor interaction was found between curing conditions, surface polishing methods and resin composites (P<0.05) in deltaE*SCE-SCI and Ra results. Additionally, significant differences were found between composites and between polishing methods (P<0.05). Furthermore, there were significant differences between curing conditions in Ra results (P<0.05).

Implant-prosthetic rehabilitation of a patient with nonsyndromic oligodontia: a clinical report.

Oligodontia is defined as the absence of 6 or more permanent teeth due to the hypodevelopment of tooth germs. This familial abnormality is attributable to various mutations or polymorphisms of genes and associated with malformative syndromes. This clinical report presents the multidisciplinary dental treatment planning for a 27-year-old woman who exhibited oligodontia. After radiographic and clinical evaluations, 7 retained primary teeth and 2 mandibular third molars were extracted. Three dental implants were placed into the maxillary alveolar process. After the osseointegration period, complete-arch fixed prostheses in both maxilla and mandible, supported by a combination of implants and teeth, were fabricated. Osseointegration of the implants, peri-implant mucosa health, and prosthesis function were assessed every 6 months. At the end of the 3-year clinical follow-up, the patient was satisfied with the esthetics, function, and phonation of her prosthesis. To attain the best esthetic and biological results, an interdisciplinary approach could be used to synergistically combine surgery and restorative dentistry for the restoration of maximal esthetics and function.

Evaluation of the Bond Strength of Polyetherketoneketone to Dental Ceramic.

PURPOSE: To evaluate the efficacy of different surface treatments on the bond strength of polyetherketoneketone (PEKK) to ceramic materials. MATERIALS AND METHODS: PEKK test specimens were separated into four groups according to surface treatments (group S: sandblasting; group A: acid etching; group SA: sandblasting + acid etching; group C: control). Surface roughness values of PEKK specimens were measured before and after surface treatment. After the prepared PEKK specimens were bonded to lithium-disilicate glass-ceramic specimens with resin cement, they were kept in distilled water at 37°C for 24 h. Half of the specimens in each surface treatment group were thermocycled. All test specimens underwent shear bond strength testing. Failure modes were assessed using light microscopy and SEM. RESULTS: Statistical analysis demonstrated that surface treatments created significant roughness on the PEKK surfaces (p = 0.005). While group S showed the highest roughness values, group A showed the lowest. Of the thermocycled test groups, the sandblasting + acid etching group obtained the highest shear bond strengths. Among the non-thermocycled test groups, the sandblasting surface treatment group achieved the highest shear bond strengths. CONCLUSIONS: The application of surface treatments to enhance the bond strength of PEKK to ceramics has proven to be effective.

Prevalence and awareness levels of color blindness among students of faculty of dentistry and dental prosthesis technology program.

Purpose: The aim of this study was to evaluate the prevalence and awareness levels of color blindness among students in a faculty of dentistry and dental prosthesis technology program in two different universities. Materials and methods: A survey of awareness of color blindness among 710 students (males: n=271; females: n=439) in the faculty of dentistry and dental prosthesis technology program of Gazi University and Ankara Medipol University in 2019-2021 was conducted. The color vision status of 442 of the students (males; n=155; females: n=287) was assessed using an online Ishihara color blindness test. The data obtained were subjected to statistical analysis using SPSS. Results: There was no statistically significant difference in the color blindness scores in terms of sex (males: 0.75±0.84; females: 0.64±0.75) (p=0.226). The color blindness scores of the dental prosthesis technology students were statistically higher than those of the faculty of dentistry students (p=0.028). Education year was significantly associated with a compromised ability to identify colors properly (p=0.040). There was no statistically significant difference in terms of awareness levels of color blindness according to the number of years of education (p>0.005). Conclusion: In terms of the prevalence of color blindness, 2.2% of faculty of dentistry and dental prosthesis technology students had a moderate-to-high level of color blindness. Students' awareness of their own color vision status was very low. The educational content of faculty of dentistry and dental prosthesis technology programs on color blindness should be enriched.

Impact of different fixed dental prostheses on radiation dose in helical tomotherapy as measured with metal oxide semiconductor field-effect transistor dosimetry.

OBJECTIVE: This ex vivo study evaluated the effects of different fixed dental prostheses and protective materials on scattered radiation during radiation therapy (RT). STUDY DESIGN: Natural teeth (group NT) and 4 types of prostheses (group BL: bilayer lithium disilicate glass-ceramic; group MZ: monolithic zirconia ceramic; group BZ: bilayer zirconia-based all ceramic; and group BM: bilayer metal-ceramic restorations) were examined in maxillary and mandibular arch phantoms. All groups were divided into 3 subgroups: (1) without protective material over the prostheses; (2) protected with a soft acrylic night guard; and (3) protected with polyvinylsiloxane putty. All groups were irradiated with helical RT at 2 Gy and 6 MV photon energy. Doses were measured internally and externally 3 times on each phantom. Results were significant at P < .05. RESULTS: No statistically significant differences in doses were found between groups NT and BL in either phantom, but these groups were different from the others. The differences between groups BZ and MZ were insignificant. Doses in group BM were significantly larger than all other groups. No significant differences existed between doses with and without protective material. CONCLUSIONS: Doses increased significantly due to scattered radiation from the prostheses with increasing material density. Protective materials had no significant effect on dose.