5-year follow-up of a prospective clinical study on various types of core restorations

PURPOSE: This study tested whether: (1) the survival rate of cast post-and-core restorations is better than the survival of direct post-and-core restorations and post-free all-composite cores; and (2)the survival of these buildup restorations is influenced by the remaining dentin height after preparation. MATERIALS AND METHODS: In a clinical trial, 18 operators made 319 core restorations in 249 patients. The restorations involved were: (1) cast post-and-core restorations; (2) direct post and composite core restorations; and (3) post-free all-composite cores. All restorations were made under single porcelain-fused-to-metal crowns. Treatments were allocated after dentin height assessment using balanced drawing. Failures were registered during a 5-year period. RESULTS: Fifteen restorations failed during the follow-up period. Five failures occurred during the first month; they were considered to be independent from clinical aging and excluded from further survival assessments. The overall survival was 96%+/-2%. No difference was found between the survivals of the different types of restorations. The factor "remaining dentin height" appeared to have a significant effect on the survival of post-and-core restorations (98%+/-2% survival for "substantial dentin height" vs 93%+/-3% for "minimal dentin height"). CONCLUSION: The type of post and core was not relevant with respect to survival. The amount of remaining dentin height after preparation influenced the longevity of a post-and-core restoration.     

Composite resin core-crown reconstructions: an up to 17-year follow-up of a controlled clinical trial

PURPOSE: The aim of this long-term follow-up study was to collect up to 17 years of survival data of endodontically treated single teeth with or without a prefabricated metal post. MATERIALS AND METHODS: Single teeth were provided with direct composite resin core-crown reconstructions with or without posts by 15 operators. Restorations consisted of either a prefabricated metal post and a composite core-crown reconstruction or a post-free direct composite reconstruction. Allocation of either restoration was performed by balanced drawing. These restorations were not covered by an artificial crown. The study sample consisted of 87 patients who received 98 core-crown reconstructions. The performance of the restorations was evaluated based on data collected from the files of the clinicians currently monitoring the oral health of the patients. The survival probability was analyzed at different levels: on the restoration level and on the level of the tooth carrying the restoration. Kaplan-Meier analysis was used to compare survival probabilities. RESULTS: Post placement showed no influence on the survival probability at either level (P > .05). The estimated overall survival rate at 17 years was 53% +/- 14% at the restoration level and 79% +/- 11% at the tooth level. CONCLUSION: The results of this long-term follow-up study showed no difference in survival probabilities between different direct composite resin core-crown reconstructions of endodontically treated single teeth (with or without a post).     

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.     

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.     

Clinical application of a fiber-reinforced post system

The tooth structure of an endodontically treated tooth was restored with a core on a post, both prefabricated with fiber-reinforced polymer-ceramic material (Sculpture/FibreKor) and subsequently with a metal-free crown. The tooth restoration is described in detail. It includes root canal preparation, polyvinyl siloxane impression taking, laboratory fabrication of the core on the post, adhesive cementation of the post-and-core system in the root canal, fabrication and cementation of the restorations, adjustment, and finishing. The success of this metal-free system is based on its increased flexural and tensile strength. Its application is safe, effective, and reliable. The high-quality aesthetics of the restorations is due to the translucency of the post-and-core material.     

Esthetic considerations in restoring endodontically treated teeth with posts and cores

Posts and cores are often required for the restoration of endodontically treated teeth. Many methods for making post-and-core reconstructions have been described. With the increased use of all-ceramic systems for esthetic tooth restorations, there is a need for esthetic core reconstructions. This article describes several methods for fabricating esthetic posts and cores. (J Prosthet Dent 1998;79:702-5.)     

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).     

The treatment of endodontically treated teeth.

Recently published studies on the treatment of endodontically treated teeth have confirmed and expanded on the restorative directions outlined in earlier work. The significance of endodontic treatment in reducing tooth strength has been questioned, and the potential influence of previous operative cavity designs highlighted. Other work has supported the contention that following the placement of a well-fitting crown, the strength of the post foundation, the core foundation, or both is relatively unimportant in determining the overall strength of endodontically treated teeth. In particular, it appears unnecessary to incorporate a ferrule effect as part of a post-and-core foundation. It seems that the height of the remaining tooth structure between the core and the crown margin is a much more significant factor in determining the fracture resistance of these teeth. Many articles have demonstrated the potential influence of material interactions at all stages of the restorative process. Further work in this area is likely to greatly complicate clinical decision making when restoring endodontically treated teeth.     

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.     

Fracture resistance of endodontically treated anterior teeth restored with four post-and-core systems.

OBJECTIVE: The purpose of this study was to evaluate the fracture resistance and the mode of failure of endodontically treated teeth restored with four post-and-core systems. METHOD AND MATERIALS: Forty intact human incisors were randomly divided into four groups. Teeth from each group received endodontic therapy and one of four post-and-core systems: serrated, parallel-sided, cast post and core; serrated, parallel-sided, prefabricated post and resin-composite core; carbon-fiber-reinforced (CFC) post and resin-composite core; and ceramic post and resin-composite core. A full-coverage metal crown was fabricated and cemented onto each tooth. Each specimen was subjected to a compressive load at a 45-degree angle to its axis until failure. The failure load was recorded and compared statistically. The mode of failure of the specimens was analyzed. RESULTS: There was no significant difference in the failure loads among groups. More catastrophic root fracture was detected in the group restored with ceramic posts and resin-composite cores. CONCLUSION: The fracture resistance of endodontically treated teeth restored with these four post-and-core systems could be accepted clinically. Unfavorable tooth fracture was shown in all groups.     

Survival of Dicor glass-ceramic dental restorations over 16 years. Part III: effect of luting agent and tooth or tooth-substitute core structure.

STATEMENT OF PROBLEM: The influence of different types of restorative design features on the long-term survival of Dicor glass-ceramic restorations is only partially understood. PURPOSE: This study examined the effect of different types of luting agents and preparation core structures on the survival of Dicor glass-ceramic restorations functioning in vivo. MATERIAL AND METHODS: A total of 1444 Dicor glass-ceramic restorations were placed on the teeth of 417 adults. Failure was defined as a restoration that required remake because of material fracture. The survival of restorations of different types, with different luting agents and preparation core structures, was described with Kaplan-Meier survival functions. The significance of differences in survival between different tooth or tooth-substitute preparation core structures and different luting agents was determined with the log-rank test. RESULTS: The probability of survival of a typical acid-etched Dicor restoration luted to gold preparation core structures was 91% at 16 years compared with 75% for dentin preparation core structures (P<.01). The survival of acid-etched Dicor restorations luted to dentin preparations was significantly better than nonacid-etched restorations luted to dentin. Acid-etched Dicor restorations luted with resin composite exhibited a more favorable survival function than those luted with glass ionomer (P<.01) and zinc phosphate (P<.05). Differences between restorations luted with glass ionomer or zinc phosphate agents were not significant. CONCLUSION: Acid-etched Dicor restorations luted to gold preparation core structures exhibited significantly better intraoral survival than restorations luted to dentin. Acid-etched Dicor restorations survived better than nonacid-etched restorations when luted to dentin preparations. Acid-etched Dicor restorations luted with resin composite exhibited more favorable survivor functions than restorations luted with glass ionomer or zinc phosphate agents.     

Restoration of endodontically treated teeth: contemporary concepts and future perspectives

The concept of using a root for the restoration of a missing crown is not new. Through continuous research, our understanding of the causes of failure has improved. Recent research on endodontically treated teeth has changed contemporary views concerning some principles while consolidating others. Clinical success in restoring endodontically treated teeth depends on our ability to use the latest materials available in conjunction with sound clinical methods. A number of articles have discussed the major factors that play a key role in the long-term survival of endodontically treated teeth and associated restorations. The purpose of this article is to identify key principles that affect tooth and restoration survival and to present expectations regarding optimal future solutions for the long-term retention of endodontically treated teeth.     

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.     

Estimation of the Risk of Failure for an Endodontically Treated Maxillary Premolar With MODP Preparation and CAD/CAM Ceramic Restorations

IntroductionThis study evaluated the risk of failure for an endodontically treated premolar with mesio occlusodistal palatal (MODP) preparation and 3 different computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic restoration configurations.MethodsThree 3-dimensional finite element (FE) models designed with CAD/CAM ceramic onlay, endocrown, and conventional crown restorations were constructed to perform simulations. The Weibull function was incorporated with FE analysis to calculate the long-term failure probability relative to different load conditions.ResultsThe results indicated that the stress values on the enamel, dentin, and luting cement for endocrown restoration were the lowest values relative to the other 2 restorations. Weibull analysis revealed that the individual failure probability in the endocrown enamel, dentin, and luting cement obviously diminished more than those for onlay and conventional crown restorations. The overall failure probabilities were 27.5%, 1%, and 1% for onlay, endocrown, and conventional crown restorations, respectively, in normal occlusal condition.ConclusionsThis numeric investigation suggests that endocrown and conventional crown restorations for endodontically treated premolars with MODP preparation present similar longevity.     

Finite element stress analysis of short-post core and over restorations prepared with different restorative materials

The present study was conducted to determine the effect on the distribution of stress with the use of short-post cores and over restorations composed of different materials. The restorative materials used were namely two different composite resin materials (Valux Plus and Tetric Flow), a polyacid-modified resin material (Dyract AP), and a woven polyethylene fiber combination (Ribbond Fiber + Bonding agent + Tetric Flow). Finite element analysis (FEA) was used to develop a model for the maxillary primary anterior teeth. A masticatory force of 100 N was applied at 148 degrees to the incisal edge of the palatal surface of the crown model. Stress distributions and stress values were compared using von Mises criteria. The tooth model was assumed to be isotropic, homogeneous, elastic, and asymmetrical. It was observed that the highest stress usually occurred in the cervical area of the tooth when Tetric Flow was used as the short-post core and over restoration material. The same maximum stress value was also obtained when Ribbond fiber + Tetric Flow material was used for the short-post core. The results of FEA showed that the mechanical properties and elastic modulus of the restorative material influenced the stresses generated in enamel, dentin, and restoration when short-post core restorations were loaded incisally. Resin-based restorative materials with higher elastic moduli were found to be unsuitable as short-post core materials in endodontically treated maxillary primary anterior teeth.     

A 3-year clinical evaluation of endodontically treated posterior teeth restored with two different materials using the CEREC AC chair-side system

Statement of problem

The introduction of polymer-infiltrated ceramic network (PICN) materials may provide more options for dentists in restoring short clinical crowns and extensively damaged posterior teeth, but clinical data for their performance are lacking.

Survival of extensively damaged endodontically treated incisors restored with different types of posts-and-core foundation restoration material

Statement of problem

Which post-and-core combination will best improve the performance of extensively damaged endodontically treated incisors without a ferrule is still unclear.

预成钛合金螺纹桩保留残根的临床修复观察

目的观察钛合金螺纹桩对残根残冠的修复效果。方法对2002年~2009年5月份期间采用钛合金螺纹桩加双固化树脂核修复的病例进行复诊观察并用预定标准评价修复效果。根据患牙的牙位、余留牙体组织量、桩与牙根的直径比及桩在根管内的密合程度对复诊的病例进行分组比较。结果复诊病例共40例,有49颗修复牙,门诊复诊病例23例共25颗修复牙。失败病例中桩折断两例,桩脱落三例。失败病例均发生在余留牙体组织量不理想组。结论螺纹桩在余留牙体组织量理想的情况下可以获得满意修复效果,在牙体缺损较多的情况下修复效果欠佳。     

冠根斜折牙体重塑后桩核冠修复对抗折力的影响

目的比较三种冠根斜折牙经牙体重塑与不重塑,桩核冠修复后的抗折强度及牙折形式。方法对42颗近期拔除的形态、大小相似、根管治疗后的完整的人上颌中切牙,截冠后随机分为七组:唇舌向、舌唇向、近远中向冠根斜折经牙体重塑及不重塑组、无斜折对照组。经铸造桩核及铸造全冠恢复外形,自凝塑料包埋后,固定于生物力学试验机上测试实验牙的抗折强度并观察其抗折类型,应用SPSS分析软件进行统计学分析。结果冠根斜折牙体重塑后桩核冠修复的抗折强度高于不重塑者;近远中向斜折重塑与不重塑组二者无统计学差异;不重塑的冠根唇向斜折牙的抗折强度明显高于舌向斜折者。结论牙体重塑能提高冠根斜折牙的抗折强度;牙折形式与牙体重塑与否无关。     

The finite element analysis of the effect of ferrule height on stress distribution at post-and-core-restored all-ceramic anterior crowns

The purpose of this study was to compare the effect of ferrule with different heights on the stress distribution of dentin and the restoration-tooth complex, using the finite element stress analysis method. Three-dimensional finite element models simulating an endodontically treated maxillary central incisor restored with an all-ceramic crown were prepared. Three-dimensional models were varied in their ferrule height (NF: no ferrule, 1F: 1-mm ferrule, and 2F: 2-mm ferrule). A 300-N static occlusal load was applied to the palatal surface of the crown with a 135° angle to the long axis of the tooth. In addition, two post and core materials with different elastic modulus were evaluated. The differences in stress transfer characteristics of the models were analyzed. Maximum stresses were concentrated on force application areas (32.6–32.8 MPa). The stress values observed with the use of a 2-mm ferrule (14.1/16.8 MPa) were lower than the no-ferrule design (14.9/17.1 MPa) for both the glass fiber-reinforced and zirconium oxide ceramic post systems, respectively. The stress values observed with zirconium oxide ceramic were higher than that of glass fiber-reinforced post system. The use of a ferrule in endodontically treated teeth restored with an all-ceramic post-and-core reduces the values of von Mises stresses on tooth-restoration complex. At rigid zirconium oxide ceramic post system, stress levels, both at dentin wall and within the post, were higher than that of fiber posts.