Synergistic effect of graphene oxide/calcium phosphate nanofiller in a dentin adhesive on its dentin bond integrity and degree of conversion. A scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared, micro-Raman, and bond strength study.

The objective was to formulate and analyze a dentin adhesive incorporated with graphene oxide (GO) nanoparticle and calcium phosphate (CaP) composite. Methods comprising of scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy, shear bond strength (SBS), and Fourier transform infrared (FTIR) spectroscopy were used to characterize nanoparticle composite, dentin bond toughness, degree of conversion (DC), and adhesive-dentin interaction. Postsynthesis of GO nanoparticles, they were functionalized with CaP using standard process. The GO-CaP composite was not added to experimental adhesive (negative control group, GO-CaP-0%), and added at 2.5 and 5 wt% to yield GO-CaP-2.5% and GO-CaP 5% groups, respectively. Teeth were set to form bonded samples utilizing adhesives in three groups for SBS testing, with and without thermocycling. The homogenous diffusion of GO-CaP composite was verified in the adhesive. Resin tags having standard penetrations were observed on SEM micrographs. The EDX analysis confirmed the occurrence of calcium, phosphorus, and carbon ions in the composite containing adhesives. The SBS test revealed highest mean values for GO-CaP-5% followed by GO-CaP-2.5%. The FTIR spectra verified the presence of apatite peaks and the micro-Raman spectra showed characteristic D and G bands for GO nanoparticles. GO-CaP composite in dentin adhesive may improve its bond strength. The addition of 5 wt% resulted in a bond strength that was superior to all other groups. GO-CaP-5% group demonstrated lower DC (to control), uniform distribution of GO and CaP composite within adhesive, appropriate dentin interaction, and resin tag formation.

Effect of Apical Root Canal Perforation Size on Push-out Bond Strength of Glass Fiber Dowels.

AIM: To evaluate in vitro effect of apical root canal perforation size on push-out bond strength of glass fiber dowels cemented to sound or perforated root canals using two different adhesive systems. MATERIALS AND METHODS: A total of 120 human-extracted intact upper central incisors were selected. Teeth were sectioned 3 mm coronal to cement enamel junction, and the remaining root received endodontic root canal therapy. The roots were divided into two experimental groups according to the root condition: either sound (n = 40) or apically perforated (n = 80). Dowel spaces were prepared for all specimens to a depth of 10 mm. Roots were restored with glass fiber dowels. The experimental group was further subdivided into four subgroups (n = 20) according to the adhesive system used and apical perforation size: group I, perforated root 2 mm apically, dowel cemented using total-etch adhesive cement; group II, perforated root 2 mm apically, dowel cemented using self-etch adhesive cement; group III, perforated root 4 mm apically, dowel cemented using total-etch adhesive cement; and group IV, perforated root 4 mm apically, dowel cemented using self-etch adhesive cement. The control group, sound root, was divided into two subgroups: group I, sound root, dowel cemented using total-etch adhesive cement, and group II, sound root, dowel cemented using self-etch or total-etch adhesive cement. Each root was then cut horizontally, and root segments were prepared to be tested. The bond strength between dowel and dentin was measured with universal testing machine using a push-out test. The two-way analysis of variance (ANOVA) was used to analyze the data and post hoc Tukey's test (α = 0.05). RESULTS: Root canal perforation and the type of adhesive system used resulted in significant differences in push-out bond strength (p < 0.05). Regardless of root canal perforation size, glass fiber dowels in normal root canals had significantly higher mean bond strength values (9.2 ± 1.4 MPa) compared with perforated root canals (6.1 ± 1.4 MPa). Also, self-etch protocol had significantly higher mean bond strength values (9.1 ± 1.3 MPa) compared with total-etch protocol (6.2 ± 2.1 MPa). CONCLUSION: The apical root perforation size caused a direct effect on the bond strength of the glass fiber dowels cemented to dentin by reducing the bond strength values to the root dentin regardless of the adhesive system used. CLINICAL SIGNIFICANCE: Prior to perforation repair, dentist or endodontist should evaluate the perforation size to predict the treatment outcome.

Influence of abutment material on the shade of dental implant restorations in the esthetic zone: a single case report.

High esthetic demand and expectation challenges the rehabilitation of the esthetic zone with dental implants. Most implant system manufacturers offer customized and prefabricated ceramic, specifically zirconia or alumina abutments, as an alternative to titanium or gold alloy abutments, with the aid of computer-aided designing/computer aided manufacturing (CAD/CAM) technology. A 45-year-old male patient was referred to the prosthodontics clinic for the restoration of maxillary central incisors with all ceramic dental implants. After healing, both implants were restored with all-ceramic crowns but different customized abutment materials for the purpose of comparison. The all-ceramic crown was cemented on a customized zirconia abutment at the implant site # 11 and on a customized gold alloy abutment at implant site # 21. The treating dentist as well as two prosthodontists performed a meticulous clinical examination to compare the ceramic crowns side by side and agreed that the outcome was esthetically satisfactory. The patient was satisfied with the esthetics and functional outcome of the final restorations, as was the prosthodontist.

Evaluation of the Effect of Glow Discharge Plasma Surface Treatment on Bonding Cements to Zirconia.

BACKGROUND: The major difference in the chemical composition of Y-TZP ceramics, as compared with conventional porcelain, led researchers to develop alternative solutions for achieving durable and long term bonding with the zirconia surface. OBJECTIVE: The study aims to evaluate the effects of glow discharge treatment on the bonding between cement and zirconia. METHODS: The zirconia rings and rods were prepared with the Zirconia Y-TZP powder and TZ-3YSB-E (Tosoh-Zirconia) through auto-mix to investigate the glow discharge and thermo-cycling. An orientation Teflon mold was used to centralize each rod into the zirconia ring, and aided as a cementation jig during the cementation procedure. RESULTS: Cohesive failure (2/3 or more of luting agent remained on the zirconia surface) has been majorly observed with RelyX Ultimate, while adhesion failure (less than 1/3 of the luting agent remained on the zirconia surface) has been primarily observed in Ketac-Cem. Mixed failure was observed among the three specimen including Rely X Unicem 2, Multilink Auto-mix and Ceramir. CONCLUSION: The glow discharge surface treatment procedure had a major impact on bond strength to zirconia.

Effects of using Antifungal Gel on Retentive Bond Strength of Two Forms of Denture Adhesives: An in vitro Study.

AIM: The purpose of this in vitro study is to compare the bond strength to denture acrylics efficacy of miconazole gel against two denture adhesives with improved retentive properties (zinc-free PoliGrip cream and Snug denture soft cushion). MATERIALS AND METHODS: Eight heat-cured acrylic samples were prepared measuring 0.7 cm × 1.4 cm flat tested surface. The two well-adapted tested surfaces were matched and fixed to Universal Testing Machine clamp. Vertical separating load was applied at a rate of 1 mm/min to yield the maximum load before denture adhesive failure occurs. These measurements were used to express the retention bond strength when improved denture adhesive material was applied alone in comparison with micon-azole nitrate gel. Results were analyzed using one-way analysis of variance (ANOVA) statistical analysis at p-value of < 0.05. RESULTS: There was a statistically significant reduction in the mean tensile strength when the antifungal gel was opposed by the zinc-free PoliGrip cream. However, such a significant difference was not evident when the Snug denture cushion was opposed by the miconazole gel. CONCLUSION: The addition of antifungal gel to denture adhesives reduces retentive bond strength of denture adhesives to denture acrylics. However, if an antifungal gel has to be used, then a denture adhesive cushion soft plastic liner may provide a better retentive option than denture adhesive cream. CLINICAL SIGNIFICANCE: The incorporation of an antifungal agent into denture adhesives is required in many denture patients to suppress fugal growth and eliminate the undesirable health effects associated with such infections.

Effect of Surface Treatments and Adhesive Materials on the Shear Bond Strength of Artificial Denture Teeth to Denture Base Resins.

AIM: The purpose of the current study was intended to evaluate the effect of different surface modifications and different adhesive materials on the shear bond strength of artificial teeth to heat-polymerized and thermoplastic denture base materials using different repair techniques. MATERIALS AND METHODS: Forty cross-linked artificial teeth used to construct different types of acrylic based denture prosthesis were selected to be bonded to two types of denture base materials, heat-polymerized acrylic resin denture base material, and thermoplastic acrylic resin denture base material. The specimens were divided into four subgroups according to the repair technique and adhesive material used. The base surfaces of all acrylic teeth then were moistened with monomer prior to bonding to the denture base specimens. Then, the specimens were tested using Universal Testing Machine for shear bond strength. The results were analyzed by using two-way analysis of variance (ANOVA) statistical analysis and multiple comparison tests, α ≤ 0.05. RESULTS: The effect of the types of denture base materials vs the surface conditioning methods displayed a statistically significant difference. CONCLUSION: This study concluded that monomer surface treatment of the bonded surface of artificial denture teeth and the use of cyanoacrylate adhesive followed by additional microwave polymerization displayed better shear bond strength when compared with other repair techniques. CLINICAL SIGNIFICANCE: Artificial teeth debonding from their denture bases is a common complication in dental practice. The current study evaluates different repairing techniques. Within the limitation of this study, the use of cyanoacrylate adhesive in combination with microwave polymerization is one of the best techniques of repairing denture teeth debonding.

Peri-implant soft tissue status and crestal bone levels around adjacent implants placed in patients with and without type-2 diabetes mellitus: 6 years follow-up results.

BACKGROUND: The long-term success and survival of dental implants type-2 diabetic subjects is debatable. PURPOSE: The present 6 years' follow-up prospective clinical study compared the peri-implant soft tissue status and crestal bone loss (CBL) around adjacent implants placed among type-2 diabetic and nondiabetic subjects. MATERIALS AND METHODS: Type-2 diabetic (Group-1) and nondiabetic individuals (Group-2) with adjacent dental implants were included. Hemoglobin A1c (HbA1c) levels were recorded; and a questionnaire was used to collect demographic information. Information regarding implant dimensions, duration in function, loading protocol, and type of restoration was recorded. Peri-implant bleeding-on-probing (BOP), plaque index (PI), probing depth (PD), and mesial and distal CBL were measured. P < .05 were considered statistically significant. RESULTS: Eighty-six male participants (44 in Group-1 and 42 in Group-2) were included. The mean age of individuals in groups 1 and 2 were 57.6 ± 5.5 and 61.6 ± 4.3 years, respectively. In Group-1, the mean duration of type-2 diabetes was 10.1 ± 3.5 years. A family history of diabetes was more often reported by individuals in Group-1 than Group-2. In groups 1 and 2, 44 and 42 pairs of adjacent implants, respectively were placed in the regions of missing premolars and molars in both arches. All implants were delayed loaded and were fixed with non-splinted screw-retained restorations. In groups 1 and 2, tooth-brushing twice daily was reported by 79.5% and 85.7% individuals, respectively. There was no difference in peri-implant PI, BOP, PD, mesial and distal CBL and HbA1c levels among individuals in groups 1 and 2. CONCLUSION: Adjacent implants can remain esthetically and functionally stable in type 2 diabetic patients in a manner similar to healthy individuals provided glycemic levels are strictly controlled and maintained.

Association of advanced glycation end products with peri-implant inflammation in prediabetes and type 2 diabetes mellitus patients.

BACKGROUND: It is postulated that peri-implant sulcular fluid (PISF) levels of advanced glycation end products (AGEs) are higher with high glycemic levels. PURPOSE: In the present clinico-biochemical study, we explored the clinical and radiographic peri-implant parameters and levels of AGEs among prediabetic, type 2 diabetic (T2DM), and non-diabetic patients and to evaluate the correlation of AGEs with clinical peri-implant parameters. MATERIALS AND METHODS: Ninety patients were divided into three groups of 30 patients each; group 1: patients with prediabetes; group 2: patients with T2DM; and group 3: non-diabetic individuals. Clinical and radiographic peri-implant parameters assessed included plaque index (PI), bleeding on probing (BOP), probing depth (PD), and marginal bone loss (MBL). PISF was collected and analyzed for AGEs levels using enzyme-linked immunosorbent assay. Between-group comparison of means was verified with Kruskal-Wallis test and Pearson correlation coefficient for correlations of AGE levels with peri-implant parameters. RESULTS: Mean peri-implant PI, BOP, PD, and MBL was significantly higher in group 1 and 2 as compared with non-diabetic patients (P < .05). Mean PI, BOP, PD, and MBL were comparable between group 1 and group 2 patients (P > .05). Mean levels of AGEs in PISF were significantly higher among prediabetic and T2DM patients as compared with non-diabetic patients (P < .05). Between group 1 and group 2, mean levels of AGEs was significantly higher in group 2 (P < .05). A significant positive correlations were found between levels of AGEs and PD (P = .0371) and MBL (P = .0117) in T2DM patients, respectively. CONCLUSION: Clinical and radiographic peri-implant parameters were worse and levels of AGEs in PISF were increased in individuals with prediabetes and T2DM. AGEs may play an important role in peri-implant inflammation in prediabetes and T2DM.

Assessment of matrix metalloproteinase-8 and -9 levels in the peri-implant sulcular fluid among waterpipe (narghile) smokers and never-smokers with peri-implantitis.

OBJECTIVES: It is hypothesized that levels of matrix metalloproteinase (MMP)-8 and MMP-9 are significantly higher in the peri-implant sulcular fluid (PISF) of waterpipe-smokers (WS) compared with never-smokers with peri-implantitis. The aim of the present convenience sample case-control study was to compare the levels of MMP-8 and MMP-9 in the PISF of WS and never-smokers with peri-implantitis. MATERIAL AND METHODS: Individuals smoking waterpipe (Group 1) and never-smokers (Group 2) were included. Demographic data was collected using a questionnaire. Peri-implant probing depth (PPD) was measured and crestal bone loss (CBL) was measured on digital bitewing radiographs. PISF samples were collected using paper strips and the collected PISF volume was determined. Levels of MMP-8 and MMP-9 were measured using enzyme-linked immunosorbent assay. Study sample-size was estimated and statistical analysis was performed. p values < .05 were considered statistically significant. RESULTS: Sixty-six individuals (33 individuals in Group 1 and 33 in Group 2) were included. In Groups 1 and 2, 41 and 44 implants, respectively were placed. The mean total PPD (p < .001) and peri-implant CBL (p < .001) was statistically significantly higher around implants affected by peri-implantitis in Group 1 compared with Group 2. The PISF volume (p < .05) collected and levels of MMP-8 (p < .01) and MMP-9 (p < .01) were statistically significantly higher among individuals in Group 1 compared with Group 2. CONCLUSION: PISF levels of MMP-8 and MMP-9 are significantly higher among WS compared with never-smokers with peri-implantitis.

Degree of conversion of resin cement with varying methacrylate compositions used to cement fiber dowels: A Raman spectroscopy study.

STATEMENT OF PROBLEM: Studies on the degree of conversion of dental cement in relation to the number of methacrylate components are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the degree of conversion of single- and multicomponent methacrylate-containing dental cements around opaque and translucent fiber dowels at varying depths. MATERIAL AND METHODS: Teeth were prepared for standard endodontic therapy, and a dowel space was created. Opaque and translucent fiber dowels consisting of Aestheti-Plus (AP) and FiberKleer were cemented with 4 methacrylate (MA)-containing cements, including RelyX U100 (R), which contains TEGDMA; Duolink (D), which contains TEGDMA and BisGMA; and Variolink N LC (V) and Breeze (B), which contain TEGDMA, BisGMA, and UDMA. Light-emitting diode polymerization was performed for 60 seconds. The specimens were immediately cut into halves and measured within the first hour at depths of 1, 3, and 5 mm using Raman spectroscopy, and the degree of conversion (DC) of resin cement was calculated. Data were analyzed using 3-way ANOVA and the Tukey multiple comparison test (α=.05). RESULTS: The measured dowel regions were not significantly different at various depths (P=.10). The dowel and cement types significantly influenced the degree of conversion of the cement (P<.05). The V and B cements exhibited a higher DC than D and R cements. With AP dowels, the DC of cement D was lower than that of the V, B, and R cements. CONCLUSIONS: Within the limitations of this in vitro study, the degrees of conversion of the tested resin cements were not affected by the tested dowel depths. Higher DC was found in cement with more than 2 types of flexible MA. Opaque dowels produced a lower DC than translucent dowels.