Up to 17-year controlled clinical study on post-and-cores and covering crowns

OBJECTIVE: The aim of this long-term follow-up was to collect up to 17-year survival data of different metal post-and-core restorations with a covering crown. METHODS: At initiation of the study, a controlled clinical trial, single tooth was provided with an artificial covering crown, by 18 operators. Restorations under investigation were the post-and-core restorations: cast post-and-core restorations, prefabricated metal post and resin composite core restorations, and post-free all-composite core restorations. Before treatment allocation, the recipient tooth was categorized according to the expected dentin height after tooth preparation. A tooth was assessed to have "substantial dentin height" (Trial 1) or "minimal dentin height" (Trial 2). The study sample consisted of 257 patients that received 307 core restorations. The performance of the restorations was based on data collected from the files of the current dentists monitoring the oral health of the patients. The survival probability was analyzed at different levels: on the restoration level (S(R)), and on the level of the tooth carrying the restoration (S(T)). Kaplan Meier analyses were used to compare survival probabilities. RESULTS: "Type of post-and-core restoration" showed no influence on the survival probability (at both levels) in both trials (P-value>0.05). The 17-year survival rates at restoration level varied from 71% to 80%, and at tooth level from 83% to 92%. CONCLUSIONS: The results of this study showed no difference in survival probabilities among different core restorations under a covering crown of endodontically treated teeth. The preservation of substantial remaining coronal tooth structure seems to be critical to the long-term survival of endodontically treated crowned teeth.     

An up to 3-Year Controlled Clinical Trial Comparing the Outcome of Glass Fiber Posts and Composite Cores with Gold Alloy-Based Posts and Cores for the Restoration of Endodontically Treated Teeth

Purpose: This controlled clinical trial aimed to compare the 3-year outcomes of glass fiber posts and composite cores with gold alloy-based posts and cores for the restoration of endodontically treated teeth. Materials and Methods: One hundred forty-four patients in need of 205 restorations on endodontically treated teeth were selected and followed for 7 to 37 months (mean: 21 ± 9 months). The teeth were primarily stratified based on the remaining tissue available to restore the tooth core with or without a post. Then, randomization allocated the teeth to either test group 1 (prefabricated glass fiber posts), test group 2 (custom-made glass fiber posts), or test group 3 (composite cores without posts). The control group consisted of gold alloy-based posts and cores. All posts/cores were covered with all-ceramic single crowns. Failures were either absolute, such as root fractures or irreparable fractures of the post/core, or relative, such as loss of post retention or reparable fractures of the core. Success and survival probability lifetime curves, corrected for clustering, were drawn for the entire data set. Results: The recall rate at 3 years was 97.1%. Absolute failures consisted of two root fractures and one endodontic failure, while relative failures included three instances of retention loss of the post/core and one post fracture. Because of the low number of events, no statistical tests were performed. The success and survival probabilities over all groups together at 3 years amounted to 91.7% and 97.2%, respectively. Conclusions: After being followed for up to 3 years, both cast gold and composite post and core systems performed well clinically. Longer follow-up times are needed to detect possible significant differences. Int J Prosthodont 2011;24:363-372.     

Seven-year clinical evaluation of painful cracked teeth restored with a direct composite restoration

The purpose of this study was to investigate long-term clinical effectiveness of treating painful cracked teeth with a direct bonded composite resin restoration. The hypothesis tested was that cracked teeth treated with or without cuspal coverage showed the same performance. Forty-one patients attended a dental practice with a painful cracked tooth that was restored with a direct composite resin restoration. Twenty teeth were restored without and 21 with cuspal coverage. After 7 years, 40 teeth could be evaluated. Three teeth without cuspal coverage needed an endodontic treatment, of which 2 failed as a result of fracture. No significant differences were found for tooth or pulp survival. Three more repairable restoration failures were recorded. Mean annual failure rate of restorations without cuspal coverage was 6%; no failures in restorations with cuspal coverage occurred (P = .009). A direct bonded composite resin restoration can be a successful treatment for a cracked tooth.     

玻璃纤维桩和复合树脂直接修复儿童冠折上前牙的临床评价

目的：应用玻璃纤维桩和复合树脂直接修复儿童冠折上前牙,随访2年并评价其临床效果。方法：对37例45颗儿童冠折上前牙行完善的根管治疗后,应用玻璃纤维桩与复合树脂直接进行修复,定期复查,评价其临床效果。结果：随访期内未见纤维桩折断、根折、及根尖周病变,仅1颗出现桩的脱粘结导致桩和树脂脱落。树脂的边缘渗漏、继发龋、表面着色、树脂折裂或部分脱落偶有发生,经处理均达病人满意。结论：对于根管治疗后儿童冠折前牙,应用玻璃纤维桩和复合树脂直接进行修复是成功而有效的过渡性治疗方法,可在短期内最大限度保存牙体组织,降低根折风险。     

Long-term survival of endodontically treated molars without crown coverage: a retrospective cohort study

STATEMENT OF PROBLEM: Teeth are weakened after endodontic treatment and should, ideally, be crowned, especially posterior teeth. However, this is not always possible. Information about the longevity of endodontically treated teeth without crown coverage may assist in selecting appropriate treatment modalities. PURPOSE: The aims of this cohort study were to evaluate the survival rate for endodontically treated molars without crown coverage and to identify possible related factors. MATERIAL AND METHODS: A total of 220 endodontically treated permanent molar teeth in 203 subjects on a waiting list for fixed prosthodontic treatment at the Faculty of Dentistry-Mahidol University, Thailand, were included. Follow-up data were derived from a clinical examination and review of the dental record and radiographs. Subjects were not included in the study if teeth had provisional crowns, definitive restorations with cuspal coverage, or with dowel and core and/or crown restorations. The outcome evaluated was defined as a failure if there were negative findings in the condition of a tooth that required a restoration, tooth repair, or extraction. Tooth loss due to endodontic and periodontal reasons was excluded. The independent variables assessed were patient age, gender, location (maxilla or mandible), the existence of an opposing dentition and adjacent teeth, remaining tooth structure, and types of restorative material. Kaplan-Meier analysis with a 95% confidence level was used to calculate the survival probability, and a log-rank test was used to determine whether significant differences existed. RESULTS: Overall survival rates of endodontically treated molars without crowns at 1, 2, and 5 years were 96%, 88%, and 36%, respectively. With greater amounts of coronal tooth structure remaining, the survival probability increased. Molar teeth with maximum tooth structure remaining after endodontic treatment had a survival rate of 78% at 5 years. Restorations with direct composite had a better survival rate than conventional amalgam and reinforced zinc oxide and eugenol with polymethacrylate restorations. CONCLUSION: Within the limitations of this study, the amount of remaining tooth structure and types of restorative material have significant association with the longevity of endodontically treated molars without crown coverage.     

The influence of coronal restoration type on the survival of endodontically treated teeth

The aim of this study is to investigate the association between coronal restoration type and survival of endodontically treated teeth. A review was performed of treatment records of patients who had endodontic treatment performed in the Department of Restorative Dentistry, University Dental School & Hospital, Cork, Ireland during the period 1993-96. Demographic and dental factors such as age, gender, tooth type, coronal restoration type, and tooth status recorded at a review appointment were recorded. Tooth status at review was defined as 'tooth present' or 'tooth absent' based on the presence or absence of the endodontically treated tooth recorded in the treatment records at a review appointment held a minimum of one year following obturation of the root canal system. Of 176 teeth (166 patients) treated, survival of endodontically treated teeth was significantly more likely where restored with cast restorations (91.7%), amalgam restorations (86.5%), or composite restorations (83.0%), than teeth restored with temporary restorations (34.5%) (p<0.0001) (mean follow-up time 38 months, range 12-60 months). Survival of endodontically treated teeth was found to be associated with permanent coronal restorations. Loss of endodontically treated teeth occurred more often with those restored with temporary restorations (34.5%) than other restoration types (p<0.05).     

Fracture resistance of composite resin cores with or without prefabricated posts over different substrates

The fracture resistance of endodontically treated teeth has been an obstacle to the durability of the remaining teeth and restorations. The aim of this study was to evaluate the fracture resistance of endodontically treated bovine and human teeth that were restored with either prefabricated metal posts, glass fiber posts, or composite resin cores. Statistical analysis revealed significant difference between different substrates, but there was no statistically significant difference between different types of intraradicular posts or in the interaction between substrate and post types. The intraradicular posts do not increase the fracture resistance of endodontically treated teeth. The metal posts presented more unfavorable fracture modes when compared to glass fiber posts and composite resin cores.     

Influence of post placement in the fracture resistance of endodontically treated incisors veneered with direct composite

STATEMENT OF PROBLEM: Veneer preparations are considered to weaken endodontically treated maxillary incisors. Prefabricated posts have been controversially indicated to reinforce endodontically treated teeth before final restoration. PURPOSE: This in vitro study evaluated whether (1) veneer preparation in enamel or in enamel/dentin weakens endodontically treated maxillary incisors, (2) bonding of direct composite veneer restores the original strength of the unprepared teeth, and (3) use of prefabricated metal posts increases fracture resistance of prepared and restored teeth. MATERIAL AND METHODS: Ninety extracted human maxillary central incisors were submitted to conventional root canal treatment. Specimens were randomly divided into 8 experimental groups (veneer preparation in enamel or dentin with/without post and with/without direct composite veneer restoration) and a control group (n = 10). Specimens were loaded to fracture, and the data were analyzed statistically. RESULTS: Statistical analysis revealed that a conservative veneer preparation does not significantly reduce maxillary incisors' fracture resistance. For prepared incisors, bonding of direct composite veneer restored their original strength, and the use of posts did not increase their fracture resistance. CONCLUSION: Conservative veneer preparations involving enamel and enamel/dentin did not significantly reduce the fracture resistance of endodontically treated maxillary incisors. In addition, restoration of the intraenamel preparations with direct composite resulted in teeth more resistant to fracture than teeth having restorations in dentin. The use of posts did not improve fracture resistance of endodontically treated maxillary incisors reduced and veneered with direct composite.     

Composite dowels and cores: effect of moisture on the fit of cast restorations

A study was undertaken to evaluate the effect of interim restorations on the dimensional stability of composite post and core buildups subjected to moisture during the fabrication of cast restorations. Dimensional change associated with composite dowel and core buildups did not significantly alter the fit of cast restorations compared with natural teeth under the same conditions. The use of composite dowels and cores for the restoration of endodontically treated teeth is not contraindicated because of potential dimensional instability of the resin when exposed to moisture. Well-fitting interim restorations for either natural teeth or composite dowel and core buildups improved the fit of cast restorations 23% to 36%.     

Survival rates of endodontically treated teeth restored with fiber-reinforced custom posts and cores: a 97-month study

PURPOSE: This study aimed to assess the long-term survival rates of polyethylene fiber-reinforced posts and cores used in endodontically treated teeth over a 97-month period. MATERIALS AND METHODS: Sixty-nine patients from a private dental office who underwent endodontic treatment with coronoradicular fiber-reinforced restorations were selected and invited for evaluation. All teeth were restored with the same high-molecular-weight polyethylene fiber (Ribbond, Ribbond Inc) and resin composite cement (Enforce, Dentsply) post-and-core system by a single operator and then prepared and restored with complete cast crowns or direct resin composite. Survival functions of restorations were analyzed with Kaplan-Meier and log-rank tests (alpha = .05) and displayed according to the variable tooth location and material of the definitive restoration. RESULTS: Four posts fractured among the 36 anterior restorations evaluated, and 2 posts fractured among the 73 posterior restorations. The mean overall survival estimate was 90.2 (+/- 3.7) months (95% Cl: 82.8-97.5). There were no differences between survival functions regarding tooth location or type of restorative material as variables (P> .05). CONCLUSIONS: The results suggest that polyethylene fiber-reinforced posts with composite cores may be recommended for clinical use. Restorations evaluated in this study presented high survival rates after the 97-month follow-up period.     

Three-year clinical comparison of survival of endodontically treated teeth restored with either full cast coverage or with direct composite restoration

STATEMENT OF PROBLEM: Little information exists regarding the outcome of crown build-ups on endodontically treated teeth restored with metal-ceramic crowns or with only a direct-placed composite. PURPOSE: The aim of this study was to evaluate the clinical success rate of endodontically treated premolars restored with fiber posts and direct composite restorations and compare that treatment with a similar treatment of full-coverage with metal-ceramic crowns. MATERIAL AND METHODS: Subjects included in this study had one maxillary or mandibular premolar for which endodontic treatment and crown build up was indicated and met specific inclusion/exclusion criteria. Only premolars with Class II carious lesions and preserved cusp structure were included. Subjects were randomly assigned to 1 of the following 2 experimental groups: (1) teeth endodontically treated and restored with adhesive techniques and composite or (2) teeth endodontically treated, restored with adhesive techniques and composite, and then restored with full-coverage metal-ceramic crowns. Sixty teeth were included in the first group and 57 in the second. All restorations were performed by one operator. Causes of failure were categorized as root fracture, post fracture, post decementation, clinical and/or radiographic evidence of marginal gap between tooth and restoration, and clinical and/or radiographic evidence of secondary caries contiguous with restoration margins. Subjects were examined for the listed clinical and radiographic causes of failure by 2 calibrated examiners at intervals of 1, 2, and 3 years. Exact 95% confidence intervals for the difference between the 2 experimental groups were calculated. RESULTS: At the 1-year recall, no failures were reported. The only failure modes observed at 2 and 3 years were decementations of posts and clinical and/or radiographic evidence of marginal gap between tooth and restoration. There was no difference in the failure frequencies of the 2 groups (95% confidence interval, -17.5 to 12.6). There was no difference between the number of failures caused by post decementations and the presence of marginal gaps observed in the 2 groups (95% confidence intervals, -9.7 to 16.2 and -17.8 to 9.27). CONCLUSION: Within the limitations of this study, the results upheld the research hypothesis that the clinical success rates of endodontically treated premolars restored with fiber posts and direct composite restorations after 3 years of service were equivalent to a similar treatment of full coverage with metal-ceramic crowns.     

Risk factors for failure of glass fiber-reinforced composite post restorations: a prospective observational clinical study

Glass fiber-reinforced endodontic posts are considered to have favorable mechanical properties for the reconstruction of endodontically treated teeth. The aim of the present investigation was to evaluate the survival of two tapered and one parallel-sided glass fiber-reinforced endodontic post systems in teeth with different stages of hard tissue loss and to identify risk factors for restoration failure. One-hundred and forty-nine glass fiber-reinforced endodontic posts in 122 patients were followed-up for 5-56 months [mean +/- standard deviation (SD): 39 +/- 11 months]. Glass fiber-reinforced endodontic posts were adhesively luted and the core was built with a composite resin. Cox proportional hazards models were used to evaluate the association of clinical variables and failure rate. Higher failure rates were found for restorations of anterior teeth compared with posterior teeth [Hazard-Ratios (HR): 3.1; 95% confidence interval (CI): 1.3-7.4], for restorations in teeth with no proximal contacts compared with at least one proximal contact (HR: 3.0; 95% CI: 1.0-9.0), and for teeth restored with single crowns compared with fixed bridges (HR: 4.3; 95% CI: 1.1-16.2). Tooth type, type of final restoration and the presence of adjacent teeth were found to be significant predictors of failure rates in endodontically treated teeth restored with glass fiber-reinforced endodontic posts.     

Long-term Survival of Adhesively Luted Post-endodontic Restorations

IntroductionThe objective of this prospective clinical study was to investigate survival for endodontically treated teeth restored with adhesively luted prefabricated dentinlike or rigid posts.MethodsData were recorded for glass-fiber posts (GFPs) and compared with historical controls evaluating glass-fiber (GFP I) and titanium posts (TPs) for 128 patients. Three groups were defined based on the type of post system used: group 1, GFP I (n = 41); group 2, GFP II (n = 41); and group 3, TP (n = 46). Posts were adhesively luted with self-adhesive resin, adhesive composite core buildups were performed, and all teeth were restored with full-coverage restorations. The primary end point was restoration survival at recall. Outcome was assessed after 6, 12, 24 and up to 178 months clinically and radiographically. Data were analyzed by the Kaplan-Meier log-rank test and Cox regression analysis.ResultsAfter up to 178 months of observation, 26 restorations failed (GFP I: 10, GFP II: 9, and TP: 7) and 49 (GFP I: 18, GFP II: 12, and TP: 19) were in situ. Cumulative survival probabilities were 57.1% for the GFP I, 56.5% for the GFP II, and 71.8% for the TP groups. In bivariate Cox regression, the factors tooth type and grade of abrasion were significantly assfociated with failure. In multivariate Cox regression, none of the investigated factors were significantly associated with failure. The post system had no significant impact on tooth survival (P > .05).ConclusionsComparing GFPs and TPs, the post system had no impact on tooth survival up to 15 years. This study indicates that the effect size of post material on survival is low.     

Fatigue life of three core materials under simulated chewing conditions.

There has been an increase in the use of prefabricated post systems to restore endodontically treated teeth. Various restorative materials are being used as core buildups on these posts. The purpose of this study was to compare three core materials that are used with prefabricated stainless steel posts. Two types of prefabricated posts were placed in extracted teeth, followed by core buildups in amalgam, composite resin, or glass ionomer. The teeth were prepared for full cast crowns with the margins of the crown preparation extending 0.5 to 1.0 mm below the margins of the core buildup. Crowns were fabricated and cemented with zinc phosphate cement. A custom-designed chewing machine was used to cyclically load the teeth with vertical and horizontal forces for one million cycles or until failure occurred. Results indicated highly significant differences in the survival of the post-core-crown restorations depending on which core buildup material was used. Amalgam cores had the lowest failure rate, followed by composite resin cores. All teeth restored with crowns over glass-ionomer core buildup failed. The type of prefabricated post used had no effect on the survival of the post-core-crown restorations regardless of the core buildup used.     

国产陶瓷预成根管桩临床应用的初步评价

目的初步评价新型氧化锆陶瓷预成根管桩修复牙体缺损的临床效果。方法临床收集61例上颌中切牙或尖牙病例,均采用非金属桩+树脂核+全冠修复,其中27例用新型氧化锆陶瓷预成根管桩,34例使用目前临床常用的石英纤维桩。对上述病例修复1年后进行复查。结果 2组患牙均无粘膜过敏反应,且牙齿松动度、牙周探诊深度,X线检查均在正常范围,未出现预成根管桩松动脱落的病例,存留率均为100%。结论新型氧化锆陶瓷预成根管桩和树脂核直接修复前牙缺损初期疗效满意。     

Restoration of badly-broken down and endodontically treated teeth

Restorations of badly-broken down and endodontically treated teeth are composite resin; pin-retained amalgam or composite resin; casting onlay; prefabricated post with amalgam/composite resin/glass ionomer cement with silver powder core, and cast post & core with crown. The appropriated material and method depend on type, function and remaining tooth structure as well as tooth prognosis and economic status of the patients.     

Influence of previous restoration of the tooth on prognosis of crowns with dowels

Due to extensive loss of tooth substance the restoration of endodontically treated tooth requires intracanal dowels to give an efficient strength for the crown. The aim of our study was to investigate whether the previous type of restoration of the tooth, i.e. composite restoration with screw post versus one-piece dowel crown, has an effect on the prognosis of crowns with dowels. The material consisted of 111 single crowns and as a previous restoration there were 83 composite restorations with screw posts and 28 one-piece dowel crowns. The mean follow-up time was 78 months (range 6--163 months). The cumulative survival was 87% for one-piece dowel crowns and 84% for composite resins with screw posts. There were six root fractures, four losses of cement retention and one tooth extraction due to caries in crowns with previous composite resin with screw posts. In one-piece dowel crowns as a previous restoration there were two root fractures and one tooth extraction for periodontal reasons. In conclusion, it seems that the previous restoration has no marked effect on the prognosis of crowns with dowels when studying a composite resin restoration with screw post and a one-piece dowel crown.     

Long-term survival of endodontically treated,maxillary anterior teeth restored with either tapered or parallel-sided glass-fiber posts and full-ceramic crown coverage

Objectives

This retrospective study investigated the clinical effectiveness over up to 8 years of parallel-sided and of tapered glass-fiber posts, in combination with either hybrid composite or dual-cure composite resin core material, in endodontically treated, maxillary anterior teeth covered with full-ceramic crowns.

Methods

The study population comprised 192 patients and 526 endodontically treated teeth, with various degrees of hard-tissue loss, restored by the post-and-core technique. Four groups were defined based on post shape and core build-up materials, and within each group post-and-core restorations were assigned randomly with respect to root morphology. Inclusion criteria were symptom-free endodontic therapy, root-canal treatment with a minimum apical seal of 4 mm, application of rubber dam, need for post-and-core complex because of coronal tooth loss, and tooth with at least one residual coronal wall. Survival rate of the post-and-core restorations was determined using Kaplan–Meier statistical analysis.

Results

The restorations were examined clinically and radiologically; mean observation period was 5.3 years. The overall survival rate of glass-fiber post-and-core restorations was 98.5%. The survival rate for parallel-sided posts was 98.6% and for tapered posts was 96.8%. Survival rates for core build-up materials were 100% for dual-cure composite and 96.8% for hybrid light-cure composite.

Conclusions

For both glass-fiber post designs and for both core build-up materials, clinical performance was satisfactory. Survival was higher for teeth retaining four and three coronal walls.     

Effect of a crown ferrule on the fracture resistance of endodontically treated teeth restored with prefabricated posts

STATEMENT OF PROBLEM: Root fracture is one of the most serious complications following restoration of endodontically treated teeth. PURPOSE: The purpose of this study was to compare the fracture strengths of endodontically treated teeth using posts and cores and variable quantities of coronal dentin located apical to core foundations with corresponding ferrule designs incorporated into cast restorations. MATERIAL AND METHODS: Fifty freshly extracted canines were endodontically treated. The teeth were randomly divided into groups of 10 and prepared according to 5 experimental protocols. Control group: teeth with custom cast post and core; 0-mm group: teeth without coronal structure (no ferrule); 1-mm, 2-mm, and 3-mm groups: teeth with 1 mm, 2 mm, and 3 mm of remaining coronal tooth structure (1-, 2-, and 3-mm ferrule), respectively. All specimens in 0-mm through 3-mm (noncontrol) groups were restored with a prefabricated post (Screw-Post) and composite resin (Z100) core located superior to the different tooth structure heights. All teeth were restored with complete metal crowns. The fracture resistance (N) was measured in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by 1-way analysis of variance and Tukey test (alpha=.05). RESULTS: Significant differences (P<.001) were found among the mean fracture forces of the test groups (control group: 818.2 N; 0-mm, 1-mm, 2-mm, and 3-mm groups: 561.0 N, 627.6 N, 745.3 N, and 907.1 N, respectively). When the mode of failure was evaluated, all failures in the control group occurred due to root fracture, and all failures in the 0-mm group occurred due to core fracture. The majority of failures in the other groups occurred due to crown cementation failure. CONCLUSION: The results of this study showed that an increased amount of coronal dentin significantly increases the fracture resistance of endodontically treated teeth.     

Direct restoration of severely damaged incisors using short fiber-reinforced composite resin

OBJECTIVES: The aim of this in vitro study was to evaluate the static load-bearing capacity and the failure mode of endodontically treated maxillary incisors restored with complete crowns made of experimental composite resin (FC) with short fiber fillers, with and without root canal posts. Further aim was to evaluate the effect of fiber-reinforced composite resin (FRC) on the failure mode of the restoration. MATERIAL AND METHODS: The experimental composite resin (FC) was prepared by mixing 22.5 wt.% of short E-glass fibers (3mm in length) and 22.5 wt.% of semi-interpenetrating polymer network (IPN) resin with 55 wt.% of silane treated silica fillers. The clinical crowns of 30 human extracted maxillary incisors were sectioned at the cemento-enamel junction. Five groups of direct complete crowns were fabricated (n=6); Group A: made from particulate filler composite resin (PFC) (Grandio Caps, VOCO, control), Group B: PFC with fiber post (everStick, StickTeck), Group C: made from PFC with everStick fiber post and FRC-substructure, Group D: made from FC, Group E: made from FC with FRC-substructure. The root canals were prepared and posts were cemented with resin cement (ParaCem Universal). All restored teeth were stored in water at room temperature for 24h before they were statically loaded with speed of 1.0 mm/min until fracture. Data were analyzed using ANOVA (p=0.05). Failure modes were visually examined. RESULTS: ANOVA revealed that restorations made from experimental fiber composite resin had higher load-bearing capacity (349N) (p<0.05) than the control restorations (173N). No significant difference was found in load-bearing capacity between restorations reinforced with FRC-substructure and those without (p>0.05). CONCLUSIONS: Restorations made from short glass fiber containing composite resin with IPN-polymer matrix showed better load-bearing capacity than those made with either plain PFC or PFC reinforced with fiber post.