Effects of ferrule and diameter of parallel cast post and core on fracture resistance / Efeitos da férula e diâmetro de núcleos metálicos paralelos na resistência a fratura

Objective: The aim of this study was to evaluate the effects of using different diameters of parallel cast posts with, or without ferrule, on the overall fracture resistance of Cast Post and Core (CPC). Material and Methods: Forty (40) endodontically treated human maxillary central incisors were divided into four groups (n=10): [F1] 1.0 mm diameter post with ferrule; [NF1] 1.0 mm diameter cast post without ferrule; [F1.5] 1.5 mm diameter cast post with ferrule; [NF1.5] 1.5 mm diameter post without ferrule. For all teeth, the post space (9.0 mm, in depth) was prepared using ParaPostTM drill. CPC using base metal alloy were fabricated and were cemented using resin modified glass ionomer (RMGI) cement along with the Porcelain Fused to Metal (PFM) crowns. A universal testing machine (Instron) was used to apply horizontal force perpendicular to the long axis of the tooth at the center of lingual surface, until catastrophic failure. Data was submitted to two-way ANOVA and Scheffé tests (P<0.05). Results: Both post diameter and ferrule statistically affected the maximum load at fracture (P=0.004 and P=0.013, respectively). The highest mean values were observed for samples with ferrule and wider post size (490N), while the lowest were observed for samples without ferrule and narrower post size (254N). There was no relationship between the presence of a ferrule and post size (P=0.937). Conclusion: For endodontically treated teeth with no ferrule, a wider-diameter cast post increased fracture resistance of a CPC and PFM crown procedure. (AU)

Objetivo: O objetivo do presente estudo foi avaliar os efeitos de diferentes diâmetros de núcleos metálicos paralelos (com ou sem férula) na resistência a fratura do procedimento restaurador. Material e Métodos: Quarenta (40) incisivos centrais superiores humanos foram tratados endodonticamente e divididos em quarto grupos (n=10): [F1] Diâmetro de 1.0 mm, com férula; [NF1] Diâmetro de 1.0 mm, sem férula; [F1.5] Diâmetro de 1.5 mm, com férula; [NF1.5] Diâmetro de 1.5 mm, sem férula. Para todos os dentes, o espaço foi preparado para o núcleo (9.0 mm, em comprimento) utilizando brocas do ParaPostTM. Os núcleos metálicos e as coroas metalocerâmicas fabricadas foram cimentados utilizando-se cimento de ionômero de vidro modificado por resina. Uma máquina de ensaios universal (Instron) foi utilizada para aplicar uma força horizontal perpendicular ao longo eixo do dente, no centro da face lingual, até falha catastrófica. Os dados foram analisados através de análise de variância de dois fatores e teste de Scheffé (p<0.05). Resultados: O diâmetro do núcleo e a presença (ou ausência) de férula afteram estatiscamente a resistência máxima a fratura do procedimento (P=0.004 e P=0.013, respectivamente). Os maiores valores foram observados para amostras com férula e de maior diâmetro (490N), enquanto os menores valores foram observados para amostras sem férula e de menor diâmetro (254N). Conclusão: Para dentes tratados endodondicamente, com férula, um núcleo de maior diâmetro aumentou a resistência a fratura de procedimentos restauradores envolvendo coroas metalocerâmicas cimentadas sobre núcleos metálicos fundidos. (AU)

EFFECTS OF FIBER POST AND CASTING METAL POST IN THE RESTORATION OF LARGE AREA TOOTH DEFECT / 现代医院

Objective To evaluate the effect of repair and chewing function recovery of fiber post and casting metal post in the restoration of large area tooth defect .Methods 100 cases of patients with large area tooth defect from August 2011 to June 2013 in our hospital were chosen to research , and were divided into the control group and the experimental group.The control group were treated with casting metal post , and the experimental group were trea -ted with fiber post.The effect of repair, bite force, chewing function and inflammatory factor levels in gingival crevic -ular between two group were compared .Results Chewing efficiency and bite force of experimental group were higher than the control group, and the difference had significant significance (p <0.05).Off, loose, discoloration and frac-ture repair effect decline rate of experimental were lower than the control group , and IL -6 and IL -8 of the experi-mental group were lower than the control group .The difference were significant(p <0.05).Conclusion Fiber post could effectively improve treatment effects in the restoration of large area tooth defect , chewing functions, and the effect of repair could be greatly improved .

A clinical comparative study on fiber post-retained and metal post-retained restorations of 176 cases / 重庆医学

Objective To compare the clinical effects of fiber post‐retained and metal post‐retained restorations .Methods Two hundred teeth after root canal therapy from 176 patients were divided into 2 groups randomly and each group consisted of 100 teeth .In the experimental group ,teeth were restored with fiber post‐resin core and porcelain crown ,where cast metal‐core and porcelain crown were used in the control group .The teeth were clinically examined regularly for 2 years .The data were analyzed with Chi‐square method .Results At the end of the 2‐year follow‐up ,6 fiber posts dislocated and 2 teeth showed gingival inflammation in the experimental group ,with a clinical success rate of 92% ,the loss rate of 6% .5 gingival inflammation cases ,2 periapical inflammation cases and 7 cases of root fracture occurred in the metal post group ,and the clinical success rate was 85% ,root discount rate of 7% .There was statistical significance between the two groups (P< 0 .05) .Conclusion The loss rate ogf fiber post‐retained restoration is higher than the metal post‐retained restorations ,but the root discount rate is low ,incidence of periodontal and periapical tissue similar in the two groups can be routinely used clinically instead of metal post‐retained restoration .

The effects of commonly used dental cast metal posts and cores on MRI / 实用口腔医学杂志

Objective:To observe the influence of commonly used dental cast metal posts and cores on magnetic resonance imaging (MRI)for head and neck.Methods:Six kinds of posts and cores made of metal alloy (Ni-Cr alloy,Co-Cr alloy,titanium alloy,pure titanium,Pd-Au alloy and Au-Pt alloy)were respectively fixed on the mucosa of left palate of a volunteer.The maxillofacial region of the subjects was scanned by routine head sequences SE-T1WI and TSE-T2WI respectively.Results:ANOVA of factorial design analy-sis indicated significant differences of artifacts among metal materials(F=153.63,PCo-Cr alloy>Ni-Cr alloy>Au-Pt alloy>titanium alloy>pure titanium;two posts and cores>one post and core;SE-T1WI>TSE-T2WI.Conclusion:Different cast metal posts and cores have different influences on MRI artifact.Reasonably choosing the metal materials and scanning sequences can minimize artifacts on MRI.

Glass fiber post versus metal post in the restoration of endodontically treated teeth / 中国组织工程研究

BACKGROUND:The post and core system for residual roots and crowns can achieve satisfactory effects, when fil ing restoration, ful crowns or inlay has poor effects. OBJECTIVE:To evaluate the clinical use of glass fiber post and metal post in the restoration of endodontical y treated teeth. METHODS:A total of 106 patients with 160 endodontical y treated teeth were selected and restored with glass fiber post (n=80 teeth) and metal post (n=80 teeth) fol owed by porcelain-fused-mental crown. The restorations were evaluated clinical y for 9 to 33 months. RESULTS AND CONCLUSION:Glass fiber post treatment for 78 teeth was effective and that for two teeth were failed, with a successful rate of 98%. Metal post restoration was effective in 71 teeth and failed in nine teeth including one tooth of crown fracture, four of root fracture and four of post loss, with a successful rate of 89%. There was statistical y significant difference between two groups (P<0.05). Glass fiber post is better in convenient handling and good color and reduced probability leading to root broken for dental restoration compared with metal post.

Evaluation of resistance to displacement of metal posts with different lengths.

Aims and Objectives: to evaluate the resistance to displacement of metal intraradicular retainers of different lengths by means of the shear test. Material and Methods: Thirty-six maxillary central incisors were cross-sectioned at 16 mm from the root apex, endodontically treated and randomly divided into three groups that were treated as follows: G1 (control) preparation of 2/3 (10.6 mm) of the total root length; G2: preparation of 1/2 (8 mm) of the total root length and G3: preparation of 1/3 (5.3 mm) of the total root length. After canal preparation, a matrix was made of the coronal and radicular portions using Duralay to obtain metal intraradicular retainers. These retainers were cemented with zinc phosphate cement and subjected to the compression shear test in a Universal Test Machine (EMIC DL 2000) at a crosshead speed of 0.5 mm/minute. The results were subjected to statistical analysis by analysis of variance (ANOVA) and Newman- Keuls, which showed statistically significant difference (P < 0.01). Results: The means in Newtons and their respective standard deviations were: G1 = 972.05 (±81.36); G2 = 921.15 (±112.25); G3 = 686.66 (±113.02). Conclusion: It could be concluded that metal retainers of 2/3 and 1/2 the length of the root portion showed higher resistance to displacement values when compared with the group that had been prepared for 1/3 of the root length.

Observation for clinical effects of glassfiber post with all-ceramic-crown for incisors restoration / 中国实用护理杂志

Objective To investigate the clinical effect of glassfiber post with all-ceramic-crown for incisors restoration, providing some references for our clinical application. Methods 82 patients (100 teeth defect) in our department from October,2008 to October, 2009 were divided into group A and group B with 50 incisors in each. Glassfiber post with all - ceramic - crown was used in group A, and metal post with porcelain-fused-to-metal in group B. After one year follow-up, we observed the clinical effect. Results 49 cases were effective and 1 case failed in group A. 42 cases were effective and 8 cases failed in group B.There was statistically significant difference between the two groups. Conclusions Glassfiber post with all-ceramic-crown is better in convenient handling and good colour for incisors compared to metal post with porcelain-fused-to-metal.

A in vitro study of coronal microleakage of different post and cement systems / 实用口腔医学杂志

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.