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@#Polyetheretherketone (PEEK) is known as a high-grade engineering plastic with good mechanical properties, chemical stability and biocompatibility. Currently, PEEK materials have been widely used in prosthodontics, such as complete dentures and removable partial dentures. The relevant research shows that PEEK posts are superior to glass fiber posts, which have high tensile bond strength and bending strength. At present, few case reports of PEEK postcores have been published, and clinical case reports suggest that PEEK postcores have good oral prosthetic aesthetics and are ideal and reliable postcore crown materials. However, the preparation and surface treatment methods of PEEK require further refinement. A review of the related properties of PEEK and the prospects of its application in the field of postcore crown restoration will be presented in this paper.
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PURPOSE: The aim was to study the masking ability of high-translucency monolithic zirconia and provide guidance in selecting resin luting cements in order to mask discolored substrates. MATERIALS AND METHODS: 160 high-translucency zirconia specimens were divided into 32 groups depending on their thickness and shades. Using five shades of try-in paste, the specimens were luted onto the sub strates (Co-Cr, precious-metal, opaque porcelain-sintered Co-Cr, opaque porcelain-sintered precious-metal, and 5M3-shade zirconia). All CIELAB color parameters were measured and statistically analyzed. RESULTS: Zirconia shade and thickness and try-in paste shade affected CIELAB color parameters (P=.000) in different substrates groups, and there were interactions among these factors (P=.000). All five try-in paste shades can be chosen to achieve ΔE values of zirconia with 1.2 – 1.5 mm for masking dark-tooth-like 5M3-shade and zirconia with 1.5 mm for masking precious-metal groups < 2.6. Only suitable try-in paste shades were used, can ΔE values that less than 2.6 be achieved when applied translucent monolithic zirconia with 0.7–1.0 mm for masking dark-tooth-like 5M3-shade and zirconia with 0.7 – 1.2 mm for masking precious-metal groups. CONCLUSION: Choosing suitable resin cement shades is necessary for high-translucency monolithic zirconia to achieve ideal masking ability (ΔE < 2.6) on the dark-tooth.
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Masks , Resin Cements , SpectrophotometryABSTRACT
Objective:To observe the clinical effects of split post crown and split post-core crown in restoring the molars with low occlusogingival distance and large root furcation,and to clarify its advantages and analyze its improvement methods.Methods:Forty-nine molars of twenty-nine patients,which had been completely treated with root canal therapy,were restored by split post crown or split post-core crown according to their wills.Split post crown was used in twenty-three cases,and split post core crown was applied in the other twenty-six cases.The clinical effects of the patients in two groups were observed after 12 and 24 months follow-up.The levels of MMP-8 in gingival crevicular fluid were checked and compared 12 months after restoration.Results:The restoration success rates of split post crown were 95.7％ after 12-month treatment and 82.6 ％ after 24-month treatment,respectively;there was no significant difference between them (P＞ 0.05).The success rates of split post-core crown were 84.6％ after 12-month treatment and 52.2％ after 24-month treatment,respectively;there was significant difference between them (P＜0.05).The success rate of split post crown was significantly higher than that of split post-core crown after 24-month treatment (P＜0.05).The levels of MMP-8 in gingival crevicular fluid of the patients were close to each other,there was no statistical significance (P＞0.05).Conclusion;The split post crown shows better clinical effect in restoring the molars with low occlusogingival distance in 24 months than split postcore crown.Targeted improvement will help to improve the clinical success rate.
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Objective:To observe the clinical effects of split post crown and split post-core crown in restoring the molars with low occlusogingival distance and large root furcation,and to clarify its advantages and analyze its improvement methods.Methods:Forty-nine molars of twenty-nine patients,which had been completely treated with root canal therapy,were restored by split post crown or split post-core crown according to their wills.Split post crown was used in twenty-three cases,and split post core crown was applied in the other twenty-six cases.The clinical effects of the patients in two groups were observed after 12 and 24 months follow-up.The levels of MMP-8 in gingival crevicular fluid were checked and compared 12 months after restoration.Results:The restoration success rates of split post crown were 95.7％ after 12-month treatment and 82.6 ％ after 24-month treatment,respectively;there was no significant difference between them (P＞ 0.05).The success rates of split post-core crown were 84.6％ after 12-month treatment and 52.2％ after 24-month treatment,respectively;there was significant difference between them (P＜0.05).The success rate of split post crown was significantly higher than that of split post-core crown after 24-month treatment (P＜0.05).The levels of MMP-8 in gingival crevicular fluid of the patients were close to each other,there was no statistical significance (P＞0.05).Conclusion;The split post crown shows better clinical effect in restoring the molars with low occlusogingival distance in 24 months than split postcore crown.Targeted improvement will help to improve the clinical success rate.
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Objective To compare the effects of different composite resins as core material on the degree of microleakage in post-core repairation.Methods A total of 46 recently extracted single-rooted mandibular premolars were distributed into different groups according to different core material including ParaCore,AP-X and Ceramage.Then we used direct or indirect forming method to make post-core restorations.All of the specimens were submerged in dyes.Then,they were demineralized,dehydrated and processed to be transparent.The extent of the dye leakage was examined under a stereomicroscope.Results The microleakage value was significantly higher in Group of direct-mold-cement with ParaCore (4.94± 1.71)mm than in Group of indirect-mold-secondary-cement with ParaCore (0.91 ± 0.33) mm,Group of indirect-mold-secondary-cement with AP-X (0.87 ± 0.27) mm,and Group of indirect-mold-secondary-cement with Ceramage (1.02 ± 0.34)mm.Conclusion Different methods of building and cementing FRC post-core restorations,but not different composite resins as core material,have significant effects on the extent of microleakage in post-core repair.
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Objective To analyze the stress distribution of the weakened root dentine restored with titanium post-core crown and fiber post-core crown by finite element method.Methods The sample was scanned by Inveon Micro-CT technology from incised margin to root apex at 21 μm interval to obtain transverse data of DICOM format.The three-dimensional finite element model was created by rebuilding the morphology of maxillary central incisor with Inveon Research Workplace as well as Mimics,Geomagic and Catia software.The model was meshed and loaded to analyze the stress distribution on the weakened dentine of root by finite element method.Results The maximum stress,shearing stress and equivalent stress of the root restored with fiber post-core crown were 60%less than the stresses of the root restored with titanium post-core crown in the experiment.The stress on various parts of the root restored with titanium post-core crown was higher than that of the root restored with fiber post-core crown.Furthermore,the stress concentration occurred mainly on the labial interface of the upper 1/3 of root. Especially when the root was restored with titanium post-core crown,the stress value reached 37 .73 MPa,which was 1.9 times that of fiber post-core crown.Conclusion The finite element analysis indicates that the fiber post-core crown is better than titanium post-core crown in avoiding stress concentration and root fracture in the restoration of weakened root of maxillary central incisors.
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From January,2011 to December,2013,103 cases were selected from patients whose residual roots and crowns were restored by porcelain fusedto metal crowns after post core crown restorations.Patients were fully in-formed and randomly divided into two groups,including 51 cases receiving the post core restoration with dental root canal nail,52 cases being repaired with glass fiber post core restoration.After 6 ~12 months of follow-up observa-tion,in the group having received post core restoration with the dental root canal nail,there were 2 cases of crown root fracture,4 cases of falling off,the success rate was 88.24% (45 /51).In the group of fiber post and core res-toration,there was 1 case of crown root fracture,1 case of falling off;the success rate was 96.15% (50 /52).The restoration of fiber post core and porcelain fused to metal crown is the best choice of restoration of residual crown and root,but the root canal nail of teeth with light cured resin core is more economical,simple,easy to operate, and suitable for basic use.
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Objective To compare the influence of resin core on overall bending strength of fiber post-core restoration.Methods 60 mandibular first premolar extracted because of orthodontic treatment was selected.3M light -cured composite resin P60,medental dual-cured resin,pulpdent dual-cured resin combined with viva carbon fiber reinforced glass fiber post were applied.The changes of teeth in vitro were observed when strength was given on.Results The flexural strength of 3M light-cured composite resin was (80.182 ±9.512)N,Medental dual-cured resin was (87.805 ± 11.649) N,Pulpdent dual-cured resin was (85.458 ± 10.845) N.The flexural strength of 3 M light-cured composite resin was lower than that of medental dual-cured resin and pulpdent dual-cured resin (t =5.758,3.084,both P ＜ 0.05).There was no statistical differences of flexural strength between medental dual-cured resin and pulpdent dual-cured resin(t =0.718,P ＞ 0.05).There was large area of resin broken off after 3M light-cured composite resin core fracture.There was only fracture of medental dual-cured resin core and pulpdent dual-cured resin core.Conclusion The bending strength of dual-cured resin is better than that of highly filled light curing composite resin in large tooth hard tissue defect restoration with fiber post-core,and core broken off is rare.Dual-cured resin is better post-core materials.
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A grossly decayed tooth sometime poses difficulty in fabrication of FDP, The post core is often required to gain support from the remaining tooth structure, In a multirooted tooth where more then one root were used as support the path of insertion of post is difficult, in those cases a custom split post and core has to be fabricated. This case report describes a simple and scientific multidisciplinary approach towards management of grossly decayed tooth. The technique seems to be effective for extensively damaged teeth that lack sufficient tooth structure to create an adequate ferrule of 1.5 to 2 mm for the final crown.
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PURPOSE: To compare the fracture resistance and the mode of failure of endodontically treated teeth restored with different post-core systems. MATERIALS AND METHODS: Root canal treatment was performed on 40 maxillary incisors and the samples were divided into four groups of 10 each. For three experimental groups post space preparation was done and teeth were restored with cast post-core (Group B), stainless steel post with composite core (Group C) and glass fiber post with composite core using adhesive resin cement (Group D). Control group (A) samples were selected with intact coronal structure. All the samples were prepared for ideal abutment preparation. All the samples were subjected to a load of 0.5 mm/min at 130degrees until fracture occurred using the universal testing machine. The fracture resistance was measured and the data were analyzed statistically. The fracture above the embedded resin was considered to be favorable and the fracture below the level was considered as unfavorable. The statistical analysis of fracture resistance between different groups was carried out with t-test. For the mode of failure the statistical analysis was carried out by Kruskal-Wallis test and Chi-Square test. RESULTS: For experimental group Vs control group the fracture resistance values showed significant differences (P<.05). For the mode of failure the chi-square value is 16.1610, which means highly significant (P=.0009) statistically. CONCLUSION: Endodontically treated teeth without post core system showed the least fracture resistance demonstrating the need to reinforce the tooth. Stainless steel post with composite core showed the highest fracture resistance among all the experimental groups. Teeth restored with the Glass fiber post showed the most favorable fractures making them more amenable to the re-treatment.
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Adhesives , Collodion , Dental Pulp Cavity , Glass , Incisor , Resin Cements , Stainless Steel , ToothABSTRACT
Objective: To compare the coronal sealing abilities of different post and cement systems through measuring the value of leakage by using dye method. Methods: Fifty human mandibular premolars with single canal were divided into 6 groups randomly. A group: roots sealed by temporary material, B group: roots restored with fiber post adhered with composite resin cement, C group: roots restored with casting metal post and core adhered with composite resin and zinc phosphate cement, D group: positive control, E group: negative control. After finishing preparation and restoration of roots, microleakage was determined by using dye method. Results: The groups restored with any post and core system produced significantly less microleakage than temporary material sealing group(P<0.05). But no differences were detected between two groups bonded with the composite resin cement (P>0.05). Posts adhered with zinc phosphate luting agent produced more leakage than those with composite resin cement(P<0.05). Conclusion: Luting agent can decrease the coronal microleakage. Composite resin cement provides better sealing ability.
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Objective:To compare the effects on the size and distribution of stress of different adhesives on post-core crown restored posterior stump of teeth dentin, to discover reasonable post-crown adhesive material of posterior stump of teeth post-core crown,by three dimensional finite element analyses. Methods:Establish three dimensional finite element models of maxillary first molar post-core crown by CT scanning, Mimics and Abaqus software,which include post core,crown,tooth root, pericementum,alveolar bone and adhesive material. Divide above models into experimental and control group according to the relative adhesive material. Choose three load spots on the occlusal surface of this model, and exert 80N loading strength on each. Then calculate the peak value and distribution mode of Von mises stress,max-principle stress and shear stress. Results:In the different adhesive material experimental groups,the peak value of the stress on the dentin of the composite resin group was lower than those in zinc phosphate groups. Conclusion:On the condition of this experiment,different adhesives have different effects on the peak value and distribution of the stress on the post-core crown restored posterior stump of teeth dentin.
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Objective:To compare influence the residual dentin stress of posterior teeth post-core different materials with or without porcelain fused metal crown (PFM), in order to instruct clinically rational choice of materials. Method:Models were created by abrasive methnd which piclures were acqiured with digital camera. Three-dimensional models of maxillary first molar short in medial palatal cusp were constructed and restored with of different materials post-core on condition of having or not having PFM. Then the magnitude and distribution of model residual dentin stress were analyzed by the three-dimension finite element analysis. Result:1 When maxillaU first molar which is short in medial palatal cusp was restored with post-core and porcelain fused mental crown, its peak value of stress was evidently less than that with post-core but without porcelain fused mental crown, meanwhile, they had different stress distribution. 2 When maxillary first molar which is short in medial palatal cusp was restored with post-core and porcelain fused mental crown, post-core of different materials had little influence on peak value of stress of residual dentin, but post-core of high elasticity modulus change normal dentin stress distribution, while post-core of low elasticity modulus did not. Conclusion:On the condition of normal occlusal force, PFM is extremely important to protect no-vital tooth, which is crucial for successful post-core crown. Meanwhile, post-core of different materials show little difference in fracturing rate of tooth restored with post-core and porcelain fused menial crown, and the fracture namely happen.
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A reconstrução de dentes tratados endodonticamente freqüentemente requer a utilização de pinos e núcleos para o restabelecimento da estética e da função. A seleção de um apropriado sistema pino/núcleo é um dilema clínico, visto as amplas variedades disponíveis. O propósito deste artigo foi discutir os vários fatores que influenciam na seleção do pino e do núcleo, tais como comprimento da raiz, anatomia do dente, largura da raiz, configuração do canal, quantidade de estrutura dental coronária, força de torção, stress, desenvolvimento da pressão hidrostática, design e material do pino, compatibilidade do material, capacidade de adesão e retenção do núcleo, versibilidade, estética e material da coroa. Assim, baseadas na literatura consultada, algumas recomendações clínicas foram propostas no intuito de orientar o clínico na seleção do sistema pino/núcleo mais adequado para cada caso: 1) conservar o máximo de estrutura dental possível durante o preparo do conduto radicular; 2) pino e núcleo fundido personalizado são recomendados para canais radiculares não-circulares e quando se tem moderada a severa perda de estrutura dentária coronal; 3) pinos pré-fabricados paralelo, passivo, serrilhado e com auto-escape são recomendados para canais circulares pequenos; 4) pinos com fator anti-rotacional devem ser utilizados em situações com canais circulares; 5) adequado selamento apical deve ser mantido sem comprometer o comprimento do pino; 6) mais de um pino deve ser usado para dente curto multirradicular; 7) pinos paralelos passivos são preconizados pela adequada retenção, mas, quando a espessura de dentina apical é mínima, um pino com design paralelo-cônico deve ser indicado; 8) a capacidade retentiva da cabeça do pino facilita a retenção do material para o núcleo; 9) o pino deve assegurar compatibilidade do material, capacidade adesiva, adequada rigidez e compatibilidade estética com a restauração definitiva; 10) reversibilidade, em casos de falha, deve ser considerada; 11) o sistema deve ser de fácil uso e custo viável
The reconstruction of teeth treated endodontically frequently requests the use of post and core for the aesthetics and function restoration. The selection of an appropriate post-core system can be a clinical dilemma, seen the wide variety available. The purpose of this article was to discuss the several factors that influence in the selection of the post and core, such as root length, tooth anatomy, root width, canal configuration, amount of coronal tooth structure, torquing force, stresses, development of hidrostatic pressure, post design and material, material compatibility, bonding capacity, core retention, retrievability, esthetics and crown material. As it is, this article can serve as a guide to help the clinical in the selection of the post-core system. This way, based on the consulted literature, some clinical recommendations were proposed with the intention of guiding the clinical in the selection of the post-core system more appropriate for each case, being: 1) conserve as much remaining tooth structure as possible during the post space preparation, 2) custom-cast post and cores are recommended for noncircular root canals and when coronal tooth structure loss is moderate to severe, 3) parallel-sided, passive, serrated and self-venting prefabricated posts are recommended for small circular canals, 4) posts with an antirotational feature should be used in circular canals situations, 5) adequate apical seal must be maintained without compromising the post length, 6) more than one post must be used for multirooted short teeth, 7) passive parallel posts are advocated for adequate retention but when the apical thickness of dentin is minimal, a parallel-tapered combination post design may be preferred, 8) retentive qualities of the post head may facilitate firm retention of core material, 9) the post should ensure material compatibility, bonding ability, adequate rigidity, and esthetic compatibility with permanent restoration, 10) retrievability in the event of failure should be considered, and 11) the system should be easy to use and cost effective
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Tooth Crown , Dental Pins , Esthetics, Dental , Endodontics , Dental ProsthesisABSTRACT
Objective; To explore a new method and its clinical significance of restorative ceramo - metal by using cast metal post -core to reutilize the broken crown. Methods; 30 teeth were restored with ceramo - metal tooth by using cast metal post - core in order to preserve the old broken base tooth, and their prognoses were observed. Results: 30 teeth post - core were inserted smoothly, and PFM crowns border sealed. During 5 years follow up ,93% (28 teeth) cases were successful, although unfortunately there were 2 cases of failure with split of tooth root. Conclusion; Restoration of ceramo - metal tooth by cast metal post - core in order to reutilize the broken crown of the base tooth is convenient ,time - saving and well casted ,therefone it could be used widely in clinic.
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objective: To study the stress distribution of abutment dentin of mandibular complete overdenture based on post core abutment(COBPA). Methods: 3 D FEM was employed to investigate the stress distribution of abutment dentin of mandibular COBPA and natural abutment(NA) on standard model, the data were compared. Results: In the same loading condition, stress concentration was observed at the root end area of dentin in both COBPA and NA. When post core was applied decreased stress distribution area and increased stress value were found aroud tooth neck, decreased stress concentration was found at root end. Conclusion: In COBPA and NA the stress may be transferred to the root end along the axis. Apart from retention, post core can transfer and buffer the stress, change the way of stress transfer, and may result in cervical fracture.
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In order to explore the clinical effect of the glass fiber-reinforced composite resin post core for severe defect restoration of front teeth,sixty-two teeth were restored for forty-one patients with severe defect restoration of front teeth by glass fiber-reinforced composite resin post core plus alumina all-ceramic crown.Through 0.6-2.0 years follow up,all the prosthesis worked very well without breaking or falling off,no gum coloring except two posts fell off after the restoration at sixth month.The patients satisfied with the restoration.
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Objective:To study the stress distribution of periodontal supporting tissues of mandibular complete overdenture based on post-core abutment. Methods:3-D finite element method (FEM) was employed to investigate the stress distribution of periodontal supporting tissues of mandibular complete overdenture based on post-core abutment, the stress values of periodontal membrane and lamina dura were calculated and compared with those of natural abutment. Results:The values of stress in distal area of abutment were larger than that in medial area. Post-core reduced periodontal membrane stress value in distal area of abutment cervix dentin, as well as that in apical zone, increased the stress value in distal periodontal membrane of the middle part of root, raised the stress value of distal lamina dura of abutment cervix dentin, while reduced the stress value below the cervix dentin. Conclusion:Abutment tends to incline distally. Post-core can influence stress distribution of periodontal membrane and lamina dura and reduce the stress value on root-end.
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Objiect:To generate three-dimension finite element mode of the first maxillary molar residual root restored with post-core crown,to analyse the stress of post-core crown of posterion tooth.Methods:Models were generate by CT scan,Mimics software and Abaqus software. Result:The three-dimensional models of the first maxillary molar residual root restored with post-core crown were generated. Conclusion:The generated three-dimensional models of the first maxillary molar residual root restored with post-core crown.were highly similar in geometry and mechanics to the real instance,which could be used to study stress of posterion tooth residual root restored with post-core crown
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Objective: To compare influence of residual dentin stress on condition of different post length of posterior teeth post-core,to discover reasonable post length of posterior teeth post-core,in order to instruct clinic rational design.Methods:Models were created by abrasive method and way which pictures were acqiured with digital camera.To generate three-dimensional models of maxillary firster molar which is short in medial palatal cusp restored with post-core crown.Then analyse magnitude and distribution of model residual dentin stress by the three-dimension finite element analysis.Result:When maxillary firster molar which is short in medial palatal cusp restored with middle fusion metal post-core and porcelain fused mental crown,on condition of 1/2 post length and2/3 post lengths,it has the same magnitude of Von mises stress? most main stress ? least main stress and the same stress distribution on residual dentin.Conclusion:When maxillary firster molar which is short in medial palatal cusp restored with middle fusion metal post-core and porcelain fused mental crown,on condition of 1/2 post length and2/3 post lengths,it has no infulence in magnitude and distribution of stress of residual dentin.