The purpose of this study was to investigate the fracture strength of endodontically treated human maxillary premolars (ETP) restored with posts and metal ceramic (MC) or monolithic zirconia (MZ) ...crowns. Sixty ETP were randomly divided into 3 groups. Teeth in control group (C) received a resin filling. ETP in the MC group were restored with prefabricated metal posts, composite cores and MC crowns while in the MZ group with glass-fiber posts, composite cores and MZ crowns. Half of the specimens were loaded at a 135° angle and half under axial loading until fracture. The fracture modes were divided in repairable and irreparable using optical microscopy. Mean fracture strength was significantly higher for MC than for MZ crowns and control group only under axial loading. The distribution of repairable and irreparable failures presented no significant differences. Crown placement significantly improved the fracture strength of ETP irrespectively of post and crown type.
The purpose of this study was to investigate the fracture strength of endodontically treated human maxillary premolars (ETP) restored with posts and metal ceramic (MC) or monolithic zirconia (MZ) ...crowns. Sixty ETP were randomly divided into 3 groups. Teeth in control group (C) received a resin filling. ETP in the MC group were restored with prefabricated metal posts, composite cores and MC crowns while in the MZ group with glass-fiber posts, composite cores and MZ crowns. Half of the specimens were loaded at a 135° angle and half under axial loading until fracture. The fracture modes were divided in repairable and irreparable using optical microscopy. Mean fracture strength was significantly higher for MC than for MZ crowns and control group only under axial loading. The distribution of repairable and irreparable failures presented no significant differences. Crown placement significantly improved the fracture strength of ETP irrespectively of post and crown type.
•The highest antimicrobial efficacy for metallic ceramic crown decontamination was unveiled by morinda citrofolia.•The lowest disinfection efficacy was revealed by group 4 sterilized with 2% ...NaOCl.•Metaloceeramic crown decontamination with morinda citrofolia and sapindus masrossi substantiated equivalent antimicrobial efficacy with no color change and surface roughness.
To assess the antimicrobial effects, surface roughness (Ra), and color change (ΔE) of Morinda Citrofolia, Sapindus Mukorossi, Indocyanine green photosensitizer, and 2% NaOCl on metal ceramic crown colonized with C. Albicans, S aureus, S. mutans, and E. coli.
An aggregate of 40 (n = 10 each) Ni/Cr metal-ceramic crowns were fabricated and inoculated with the American Type Culture Collection (ATCC) of varied microbial colonies colonized by C. Albicans, S aureus, S. mutans, and E. coli. After inoculation, specimens were exposed to four different types of disinfection methods i.e. group 1: MC, group 2: SM, group 3:ICGP, and group 4 2% NaOCl respectively to evaluate antimicrobial efficacy, Ra, and color change. Later, the microbial assay was performed and expressed as CFU/ml (log 10). Ra was assessed using a surface analyzer and color change ΔE was evaluated using a spectrophotometer Statistical analysis was performed by using two-way ANOVA and Post HocTukey's test maintaining a significance level of p less than 0.05.
The highest antimicrobial efficacy for metallic-ceramic crown decontamination against all inspected microbial colonies was unveiled by group 1: MC, whereas the lowest disinfection efficacy was revealed by group 4 sterilized with 2% NaOCl (control). Metallic ceramic crown decontamination with MC and SM substantiated equivalent antimicrobial efficacy in plummeting CFU/mL (log10) of C.Albicans, S aureus, S.mutans, and E. coli (p>0.05). However, ICGP as a crown disinfectant validated antimicrobial efficacy significantly less compared to MC and SM (p<0.05). Ra was assessed post-disinfection with no changes observed (p>0.05) among all groups. Similarly, ΔE was significantly higher in crowns disinfected with ICGP (p<0.05)
Metallic ceramic crown decontamination using herbal disinfectants Morinda Citrofolia and Sapindus Mukorossi exhibited favorable antimicrobial efficacies against microbial colonies of C. albicans, S aureus, S.mutans, and E. coli with no changes in surface roughness and color.
The purpose of this study was to investigate the fracture strength of endodontically treated human maxillary premolars (ETP) restored with posts and metal ceramic (MC) or monolithic zirconia (MZ) ...crowns. Sixty ETP were randomly divided into 3 groups. Teeth in control group (C) received a resin filling. ETP in the MC group were restored with prefabricated metal posts, composite cores and MC crowns while in the MZ group with glass-fiber posts, composite cores and MZ crowns. Half of the specimens were loaded at a 135° angle and half under axial loading until fracture. The fracture modes were divided in repairable and irreparable using optical microscopy. Mean fracture strength was significantly higher for MC than for MZ crowns and control group only under axial loading. The distribution of repairable and irreparable failures presented no significant differences. Crown placement significantly improved the fracture strength of ETP irrespectively of post and crown type.
To quantify and to compare a gravimetric and three-dimensional (3D) analysis of the removed tooth structure for different complete crown preparations.
A total of 80 molar resin teeth and 8 ...preparation finishing lines were chosen: 1 for metal ceramic crowns (MCC); 3 for zirconia all-ceramic crowns: knife edge (ZirKnE), chamfer (ZirCha), and shoulder (ZirSho); 4 for lithium disilicate: light chamfer (LDLCha), chamfer (LDCha), shoulder (LDSho) and table top. Teeth were individually weighed to high precision and then prepared following the preparation guidelines. The teeth were reweighed after preparation, and the amount of structural reduction was calculated. In addition, all teeth were scanned before and after preparation, and the 3D volume of removed dental tissue was calculated, superimposing the two .stl files, as a difference of the volumes before and after the preparation. Kruskal–Wallis statistical analysis was carried out to determine significant differences among the groups with a significance level of p<0.05.
Both analyses showed that LDLCha, ZirKnE and table-top preparations produced the smallest amount of removed structure, whereas the preparations for MCC, ZirSho and LDSho were more destructive. For MCC, 2.6 times more tooth structure must be removed than for table top. ZirKnE was 17.82% and LDLCha was 21.51% more conservative than MCC. The data obtained through the volumetric method were similar with those obtained by gravimetric analysis.
ZirKnE, LDLCha, and table-top preparations produced the least amount of tooth tissue removal. Three-dimensional volumetric analysis can be a possible alternative to gravimetric analysis.
Metal-ceramic crowns (MC) have long been considered as gold standard for dental prosthetic restorations. Our study aims to evaluate the influence of MC, with conventional technology used for the ...framework, on the periodontal parameters and levels of C reactive protein, an inflammatory marker, in gingival crevicular fluid in patients diagnosed with periodontitis. Two groups were established: the test group T-28 teeth from the lateral area wearing a MC crown and the control group C-28 teeth without any wearing. These parameters were evaluated: probing depth, Gingival Index, and longevity of crowns. The quantitative assessment through enzyme-linked immunosorbent assay of the targeted pro-inflammatory mediator was performed. There is a difference statistically significant between the groups T and C regarding the marker’s levels and gingival index, a very strong correlation between these levels and probing depth and a strong correlation between longevity and Gingival Index. Periodontal clinical parameters are more pronounced the longer the time elapsed since the application of the crowns. Expression of C reactive protein is higher in the presence of MC crowns.
PURPOSEThe effect of core design on the fracture resistance of zirconia-lithium disilicate (LS2) bilayered crowns for anterior teeth is evaluated by comparing with that of metal-ceramic crowns. ...MATERIALS AND METHODSForty customized titanium abutments for maxillary central incisor were prepared. Each group of 10 units was constructed using the same veneer form of designs A and B, which covered labial surface to approximately one third of the incisal and cervical palatal surface, respectively. LS2 pressed-on-zirconia (POZ) and porcelain-fused-to-metal (PFM) crowns were divided into "POZ_A," "POZ_B," "PFM_A," and "PFM_B" groups, and 6000 thermal cycles (5/55℃) were performed after 24 h storage in distilled water at 37℃. All specimens were prepared using a single type of self-adhesive resin cement. The fracture resistance was measured using a universal testing machine. Failure mode and elemental analyses of the bonding interface were performed. The data were analyzed using Welch's t-test and the Games-Howell exact test. RESULTSThe PFM_B (1376. 8 ± 93.3 N) group demonstrated significantly higher fracture strength than the PFM_A (915.8 ± 206.3 N) and POZ_B (963.8 ± 316.2 N) groups (P<.05). There was no statistically significant difference in fracture resistance between the POZ_A (1184.4 ± 319.6 N) and POZ_B groups (P>.05). Regardless of the design differences of the zirconia cores, fractures involving cores occurred in all specimens of the POZ groups. CONCLUSIONThe bilayered anterior POZ crowns showed different fracture resistance and fracture pattern according to the core design compared to PFM.
Back ground: Fiber reinforcement was introduced to clinical dentistry for the first time in the 1960s when investigators attempted to reinforce polymethyl- methacrylate dentures with glass or carbon ...fibers. It has recently been shown that crowns, bridges and posts made of FRC can be used successfully in dental practice and they are esthetically more acceptable than conventional metal ceramic crown. Aims: A prospective comparative cross-sectional study was performed involving 60 patients who attended in the out patients department of Prosthodontics, Faculty of Dentistry, BSMMU during the period of January 2007 to December 2008. Objective: Compare fiber-reinforced composite crowns and metal ceramic crowns according to attrition of opposing teeth. Methods: Clinical data were recorded from the randomly selected 60 patients divided in to tow groups experimental and control. Attrition of opposing teeth was indexed after California Dental Associations quality evaluation system. Results: In group A patients, 12(40.0%) were male and 18(60.0%) female. In group B patients 14(46.7%) were male and 16(53.3%) were female. All the patients were in grade I in both groups after 4 months. After 8 months all patients were in grade I in group A and 29(96.7%) patients were in grade I in group B. After 12 months all patients were in grade I in group A and 28(93.3%) patients were in grade I in group B. The difference was not statistically significant (p>0.05) in chi square test. Conclusion: The Fiber Reinforced Composite crown represents a valuable development in field of Prosthetic Dentistry. DOI: http://dx.doi.org/10.3329/updcj.v4i1.21161 Update Dent. Coll. j: 2014; 4 (1): 21-26
Summary Prosthetic crowns made by galvano‐forming are considered to be highly biocompatible and aesthetic restorations. Therefore, they represent an alternative crown‐system to conventional ...metal‐ceramic crowns in replacing lost tooth structure. However, there are few data available on clinical and biochemical effects of galvano‐ceramic crowns on periodontal tissues. The purpose of this controlled study was to test the impact of galvano‐ceramic crowns and metal‐ceramic crowns on clinical and inflammatory responses of periodontal tissues. A prospective, blinded randomized clinical trial was conducted. Galvano‐ceramic crowns and metal‐ceramic crowns were placed in 52 periodontally healthy patients in split‐mouth design. Clinical parameters (gingival index, plaque index, probing depths and recessions) were recorded from six sites per tooth. Initial tissue alteration was accessed analysing the gingival crevicular fluid flow rate and IgG concentration in gingival crevicular fluid. After 24 months, 34 patients could be re‐evaluated. All crowns were in adequate function and obvious clinical inflammation was rarely observed. After 24 months of follow‐up, gingival tissues adjacent to galvano‐ceramic crowns showed significantly less signs of clinical and inflammatory responses according to plaque index (P = 0·004), gingival index (P < 0·001), gingival crevicular fluid flow rate (P = 0·012) and IgG (P = 0·002). Data were also analyzed for buccal and oral sites separately. Gingival tissues adjacent to metal‐ceramic crowns showed significantly increased clinical and inflammatory values for plaque index (P = 0·005), gingival index (P = 0·008), gingival crevicular fluid flow rate (P = 0·006), IgG (P = 0·007) at oral sites compared to galvano‐ceramic crowns. Our data suggest a stabilizing effect of galvano‐ceramic crowns on periodontal tissues over time.
Fabricating a crown to retrofit an existing abutment tooth for a partial removable dental prosthesis (PRDP) is one of the most time-consuming and labor-intensive clinical procedures. In particular, ...when the patient is concerned with esthetic aspects of restoration, the task of fabricating becomes more daunting. Many techniques for the fabrication of all-metallic or metal-ceramic crowns have been discussed in the literature. This article was aimed to describe a simple fabrication method in which a retrofitting crown was fabricated for a precise fit using a ceramic-pressed-to-metal system.
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