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Summary review of the survival of single crowns
Abstract
It generally is assumed by both dentists and patients that single crowns last a long time; however, the actual survival experience for crowns is not well-described and few comparisons have been reported in terms of survival for different types of crowns. A review of the literature reveals that while definitions of survival differ, the differences among crown types are relatively small, with all-ceramic posterior crowns demonstrating the poorest survival experience. Generally, 95% of crowns will remain in the mouth for at least five years--or, to use another definition of survival, more than 90% of crowns will not require catastrophic treatment within five years. Longer-term survival is less well-described; according to the literature, survival at 15-20 years ranges from 50-80%. These findings should help dentists and their patients to make informed treatment decisions regarding crowns.
... In contrast, conventional classical tooth preparation approaches based on crown-type restorations compromise more of the already deteriorated tooth structure [30]. Although they have demonstrated equal long-term success, with 15-20-year survival rates ranging between 50 and 80% [31], they deviate from the guidelines established in the latest European consensus statement on the treatment of severely worn teeth [1] that advocate for the use of adhesive, direct or indirect techniques, which usually allow for a second chance in cases of the failure and/or wear of the previous restoration [32]. ...
Introduction:
Currently, there is little clinical evidence to support the medium- and long-term survival and clinical performance of ultraconservative approaches using adhesive restorations in full-mouth restorations. The aim of this case series study was to evaluate the medium-term clinical performance of anterior and posterior adhesive restorations applied with direct and indirect techniques using resin composites and glass-ceramic-based materials.
Materials and methods:
The inclusion criteria were an esthetic problem as the main reason for consultation and severe generalized wear of grade 2 to 4 according to the Tooth Wear Evaluation System (TWES 2.0). In addition, at each follow-up appointment, patients were required to submit a clinical-parameter-monitoring record according to the modified United States Public Health Service (USPHS) criteria.
Results:
Eight patients with severe tooth wear were treated through full rehabilitation in a private dental clinic in Spain by a single operator (AFC). A total of 212 restorations were performed, which were distributed as follows: 66 occlusal veneers, 26 palatal veneers and 120 vestibular veneers. No signs of marginal microleakage or postoperative sensitivity were observed in any occlusal, vestibular and/or palatal restoration after the follow-up period. The estimated survival rate of the 212 restorations was 90.1% over 60 months of observation, with a survival time of 57.6 months. Only 21 restorations had complications, which were mostly resolved with a direct composite resin. The dichotomous variables of the restoration type (posterior veneer, anterior veneer) and the type of restored tooth (anterior, posterior) were the risk predictors with statistically significant influences (p < 0.005) on the survival of the restorations.
Conclusion:
According to the results of this study, there is a significantly higher risk of restorative complications in posterior teeth compared to anterior teeth. Also, it can be concluded that the indication of adhesive anterior and posterior restorations is justified in the total oral rehabilitation of patients with severe multifactorial tooth wear, as they are associated with a low risk of failure.
... The reasons may range from caries, aesthetics, root canal therapy, trauma, rehabilitations, etc., Crown placement is now a common treatment for dentists, and a lot of research and development has gone into making this process quicker, more convenient for the patient, and with more reliable S138 Journal of Pharmacy and Bioallied Sciences ¦ Volume 15 ¦ Supplement 1 ¦ July 2023 Sharma, et al.: RCT in ful crown restorations enamel and the dentine will expose the tooth interiors for the invasion of the pathogens. [1][2][3][4][5] Poorly fitted provisional crowns may make this issue worse because they can leave tubules exposed. This process may take time and may sometime years. ...
Introduction:
There are numerous chances for pulpal irritation during the placement of a crown on a tooth. This study's goal was to find and examine the variables that influence the prevalence of routine root canal therapy after the teeth were restored with full coverage crowns.
Methods:
The hospital records were retrospectively evaluated from 2000 to 2010 for a decade. The demographics as well as the various variables that caused for the intervention with the root canal therapy for the teeth with the full crowns were evaluated. The values were compared for the significance.
Results:
The total number of the teeth that were finalized in the study was 4308. Of the total teeth that were treated with full coverage crowns, 50% were metal ceramic, 42% were full ceramic, and 9% were full metal crowns. After 10 years, possibility that every tooth with a crown would survive was 91%. The most frequent adverse incident was the intervention with the RCT. Metal ceramic crowns had poor survival rates and needed the maximum intervention. Younger age-group had least survival rate than the older age-groups.
Conclusions:
Endodontic therapy is unlikely to be necessary after crown installation. As the patient's age declines and all-ceramic or PFM crowns are used, this risk rises.
... forms an integral part of dental practice. 1 It mainly satisfies the biological, mechanical, and aesthetic demands of the patient. 2 Prosthodontic treatment is very challenging and may have detrimental effect on the pulp and periodontium. It involves preparation of the tooth through removing of enamel and dentine which lead to the exposure of dentinal tubules to oral cavity making an easy pathway for the oral microbes to reach the dental pulp. ...
Purpose
: This is a systematic review aimed to identify the incidence of pulp necrosis and/or periapical changes among vital teeth which are used as an abutment for crown and fixed partial dentures (FPDs).
Materials and Methods
: Two reviewers independently searched two electronic databases, PubMed and Scopus. The search was complemented from references of included studies and published reviews. Studies published in the English language through January 2021 that had assessed and documented the clinical and radiographic failure of crown or FPD in vital permanent teeth due to pulpal or periapical pathology with a follow-up of at least 12 months were selected. Data screening, data collection and extraction of data was performed. Quality of studies involved was analyzed using the Newcastle-Ottawa Quality Assessment Scale for cohort studies. Meta-analysis was done using random effects model. Publication bias was assessed using funnel plots.
Results
: Electronic searches provided 10,075 records among which 20 studies were selected for systematic review and 7 studies were selected for meta-analysis. With respect to quality assessment, all the studies involved were considered as high quality as the score in scale ranged between 6 and 9 as per the Newcastle-Ottawa Quality Assessment Scale for cohort studies. The meta-analyses showed that there was no statistically significant difference in the incidence of the loss of pulp vitality or pulp necrosis through clinical and radiographic examination with the follow up period of 5 years: P < .001, 95% CI: 0.96-1.00, I² = 77.84%; 10 years: P < .001, 95% CI: 0.88-0.95, I² = 93.59%; 15 years: P < .001, 95% CI: 0.92-0.96, I² = 94.83%; and 20 years: P < .001, 95% CI: 0.94-0.96, I² = 95.01%.
Conclusions
: The meta-analysis revealed clinical and radiographic success rate ranging between 92% to 98% at different follow up periods ranging between 5 years and 20 years. Future high-quality randomized clinical controlled trials with a larger population are required to confirm the evidence as only observational studies were considered in this paper.
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... 5 Singleand multiple-crown restorations in particular are frequently implemented for a wide variety of indications. 6 In vitro studies have shown that crowns fabricated with a digital workflow exhibit better fit, interproximal contacts, and marginal integrity than those obtained via a conventional workflow. 3,7 On the other hand, the success of a digital impression is affected by factors such as scanner technology, scanning strategy, ambient lighting conditions, substrate type, translucency, and preparation design. ...
Purpose:
To evaluate the trueness of digital impressions of different composite resin materials that can be used for core build-ups in clinical practice.
Materials and methods:
A maxillary central incisor was prepared and scanned with an intraoral scanner (Primescan, Dentsply Sirona). Ten composite resin specimens (in three groups: universal composite; flowable composite; and bulk fill resin composite) were milled in the same dimensions of the prepared tooth and scanned. The data of the prepared tooth were used as reference, and the data obtained from the composite resin specimens were aligned with the evaluation software (Geomagic Studio 12) to determine deviation values. Kruskal-Wallis with Dunn post hoc test was performed (α = .05).
Results:
There were significant differences in the trueness of digital impressions between some composite resin groups (P < .05). The mean trueness deviation values were in the range of 12.75 μ m (G-aenial Posterior) to 17.06 μ m (Filtek Bulk Fill Posterior). The trueness of G-aenial Posterior (12.75 μ m) was higher than that of Core-X Flow (14.62 μ m), Clearfil Majesty Flow (16.93 μ m), and Filtek Bulk Fill Posterior (17.06 μ m). Filtek Bulk Fill Posterior exhibited lower trueness than Clearfil Majesty Esthetic (12.93 μ m), Clearfil Majesty Posterior (13.50 μ m), and Charisma Classic (13.81 μ m).
Conclusion:
Different composite resins used for core build-up can impact the trueness of digital impressions, with universal composite resin scans being the truest compared to flowable and bulk fill composite resin scans. All scanned substrate groups can be regarded as within a clinically acceptable range.
... Teeth restored with full coverage crowns are successfully retained for at least 5 years in 95% of patients 1 . It is known that vital teeth with crowns may develop pulpal disease 2 . ...
Introduction
to evaluate the effect of different access opening restorative materials on crown retention.
Methods
38 extracted molars were mounted in resin and prepared for porcelain fused metal crowns (PFM). The crowns were fabricated and cemented with zinc phosphate and the force to displace it was measured with a tensile-testing machine (MTS) before and after endodontic access preparations. The endodontic access area, crown preparation axial wall and preparation surface area was measured for comparison. The crowns were then recemented and access openings restored with either amalgam or composite before displacement force was remeasured. The restorative material was removed from each access opening, access area measured, and restored again (amalgam with composite or fiber post with composite) for displacement force to be re-measured. Paired T test was used to compare the means of displacement between groups. One-way analysis of variance (ANOVA) was used to compare the mean outcome measure within the groups.
Results
Statistical analyses showed retention following unfilled access was significantly lower than intact crowns. Amalgam, composite, amalgam + composite, and fiber post + composite increased retention beyond the original value. There was no statistical difference among the different restorative protocols. Qualitative results indicate that the restorative material remains in the crown following displacement regardless of the material used to restore the access.
Conclusions
The results from this study suggest that an endodontic access cavity decreases retention of a PFM crown. However, subsequent restoration with amalgam, composite, amalgam + composite, or post + composite may increase the original retention of the crown.
... This protocol is capable of producing good results. 9 The absence of conditioning with hydrofluoric acid on the ceramic surface can reduce the bond strength of the material with the cement. Poor bonding quality at the cement/ceramic interface can decrease the ability of a ceramic to resist the beginning of a fracture. ...
Objective: analyze the influence of bond strength between resin cement and feldspathic ceramics using different concentrations and application times of hydrofluoric acid (HF). Materials and Methods: 18 feldspathic ceramic discs (Ø10mm-2mm thickness) were made through the incremental technique, which were included in acrylic resin and regularized with silicon carbide sandpaper with granulations of 600, 1200 and 2000 through a polishing machine with a speed of 600 rpm. Soon after, they were immersed in distilled water for 10 minutes in an ultrasonic bath. All specimens were conditioned with HF and silanized. Four cement cylinders were made on each specimen (n=12), manufactured with Relyx ARC resin cement. After that, it was divided into six groups according to the surface treatment protocol: G1 (5%-40s); G2 (5%-60s); G3 (5%-80s); G4 (10%-40s); G5 (10%-60s) e G6 (10%-80s). The specimens were subjected to the Microshear Test, with vertical force at a speed of 0.5 mm min on the specimen. The microshear bond strength was calculated and expressed in Megapascal (MPa). The data were submitted to two-way analysis of variance (ANOVA) and Tukey's test for multiple comparisons, with a significance level of 5%. Results: when the concentration of HF was analyzed, there were no statistical differences (p>0.05). In the comparison of application times, G3 (5%-80s) and G6 (10%-80s) obtained higher results of microshear resistance than the other groups. Conclusion: The different concentrations of HF did not influence the bond strength between feldspathic ceramics and resin cement. However, the increase in the time of HF conditioning affected in the bond strength.
... For centuries, full-coverage restorations have been used to support and protect teeth after extensive caries removal, root canal therapy, or cracks. Crowns have become routine procedures for dental practitioners, and much research and development have been directed toward making these procedures more convenient for the patient, faster to complete, and have more predictable outcomes 1 . ...
Introduction: The process of restoring a tooth with a crown leaves many opportunities for pulpal irritation. The objective of this study was to identify and analyze the factors that contribute to the incidence of nonsurgical root canal therapy (NS-RCT) after the delivery of single-unit full-coverage restorations. Methods: Insurance claims from 88,409 crown placements in the Delta Dental of Wisconsin insurance database were analyzed from the years 2008-2017. The Cox regression model was used to analyze the effect of the predictor variables on the survival of the tooth. Untoward events were defined as NS-RCT, tooth extraction, retreatment of root canal, or apicoectomy as defined by the Code on Dental Procedures and Nomenclature. Results: Of 88,409 crowns placed, 8.97% were complete metal, 41.40% were all ceramic, and 49.64% were porcelain fused to metal (PFM). The probability of survival of all teeth with crowns placed was 90.41% after 9 years. NS-RCT was the most common untoward event. PFM crowns exhibited a higher rate of untoward events than complete metal crowns and a lower rate than all-ceramic crowns. Crowns placed on individuals 50 years of age and younger had higher rates of untoward events than those placed on individuals ages 51 years and older. Conclusions: The risk of endodontic treatment after the placement of crowns is low. This risk increases with the placement of all-ceramic or PFM crowns and as the age of the patient decreases. (J Endod 2020;46:605-610.)
... in restorative dentistry occurred in 1903 after the use of porcelain jacket crowns. 9,10 Ceramic systems can be classified into two groups, which are acid-sensitive or conditioned and acid-resistant or non-conditioned. The first are the systems capable of being conditioned by acids. ...
Objective: to evaluate the main characteristics of dental ceramics, resin cements, surface treatments and verification of their failure modes, in relation to the literature and their respective clinical uses. Material and Methods: a bibliographic search was conducted in the main health databases PUBMED (www.pubmed.gov) and Scholar Google (www.scholar.google.com.br), in which studies published from 2002 to 2020 were collected. Laboratory studies, case reports, systematic and literature reviews, which were developed in living individuals, were included. Therefore, articles that did not deal with the main characteristics of dental ceramics, resin cements, surface treatments and verification of their failure modes, in relation to the literature and their respective clinical uses were excluded. Results: ceramics can be classified into glass-matrix ceramics, polycrystalline ceramics and hybrid ceramics. Just as there are different compositions of ceramics and bonding agents, there are also some surface treatment protocols that vary according to the choice of these materials. Conclusion: several ceramic systems are available, making professionals in the prosthetic area need a constant update about their properties and indications, since good results are not due exclusively to the type of material used, but also to the selection of the best material, type of preparation, professional's skill, resin cements, surface treatments and verification of their failure modes. In this context, further studies are needed in relation to dental ceramics and their proper clinical use.
... For centuries, full-coverage restorations have been used to support and protect teeth after extensive caries removal, root canal therapy, or cracks. Crowns have become routine procedures for dental practitioners, and much research and development have been directed toward making these procedures more convenient for the patient, faster to complete, and have more predictable outcomes 1 . ...
Introduction
The process of restoring a tooth with a crown leaves many opportunities for pulpal irritation. The objective of this study was to identify and analyze the factors that contribute to the incidence of nonsurgical root canal therapy (NS-RCT) after the delivery of single-unit full-coverage restorations.
Methods
Insurance claims from 88,409 crown placements in the Delta Dental of Wisconsin insurance database were analyzed from the years 2008–2017. The Cox regression model was used to analyze the effect of the predictor variables on the survival of the tooth. Untoward events were defined as NS-RCT, tooth extraction, retreatment of root canal, or apicoectomy as defined by the Code on Dental Procedures and Nomenclature.
Results
Of 88,409 crowns placed, 8.97% were complete metal, 41.40% were all ceramic, and 49.64% were porcelain fused to metal (PFM). The probability of survival of all teeth with crowns placed was 90.41% after 9 years. NS-RCT was the most common untoward event. PFM crowns exhibited a higher rate of untoward events than complete metal crowns and a lower rate than all-ceramic crowns. Crowns placed on individuals 50 years of age and younger had higher rates of untoward events than those placed on individuals ages 51 years and older.
Conclusions
The risk of endodontic treatment after the placement of crowns is low. This risk increases with the placement of all-ceramic or PFM crowns and as the age of the patient decreases.
... This, also, was in accordance with results for polymer crowns in other studies 13,15 and with results for metal-ceramic crowns. 20 Some critical aspects have to be considered in order to allow clinically relevant conclusions. ...
... However, as documented, the clinical service time of the MC-crowns before these problems arise is longer than in the reported studies of most all-ceramic alternatives. 1,19 These common factors should be accounted for when any material comparisons are made. ...
Purpose:
This study aimed to present the up to 25-year clinical performance and survival of 2,340 high gold-based metal-ceramic single crowns placed in a specialist prosthodontic practice.
Materials and methods:
All crowns provided to 670 patients between 1984 and 2008 were sequentially recruited. Each crown/tooth combination was given a prognostic evaluation at cementation. Patients were recalled in 2008 and 2009 for examination, and patient records were scrutinized for any retreatment. Estimated cumulative survival, standard error, and differences in survival between groups were calculated using the Kaplan-Meier method, Greenwood formula, and log-rank test, respectively. Crown status (six-field classification) was reported within 5-year groupings and for 7, 10, and 12 years.
Results:
The up to 10-year and 25-year estimated survival rates of the 2,211 favorably rated crowns were 97.08% ± 0.45% and 85.40% ± 2.19%, respectively. The up to 12-year survival for crowns in the postimplant era was 94.4% ± 2.78%. No significant differences related to sex, tooth type, or tooth position were demonstrated. Nonvital teeth had lower overall survival rates than vital teeth, but not in crowns placed in the postimplant era. Actual 10-year outcomes closely matched the estimated 10-year survival. Biologic factors accounted for 101 of the 133 failures, while mechanical factors accounted for 8 failures and patient concerns accounted for 24 failures. Porcelain fracture requiring replacement occurred in 4 crowns.
Conclusions:
The clinical performance of the crowns was excellent. Biologic factors accounted for the majority of failures. Material stability was excellent. Patient complaints of unacceptable esthetics resulted in 22 crowns being replaced after a mean clinical service time of 14 years.
... treatment within five years of placement, with full-coverage ceramic crowns placed on posterior teeth having the lowest survival rate. 21 The results of our study are in general agreement with those of this comprehensive review, especially in view of the more stringent criteria we used to define restorative success. ...
The authors aimed to determine the outcome of and factors associated with success and failure of restorations in endodontically treated teeth in patients in practices participating in the Practitioners Engaged in Applied Research and Learning (PEARL) Network.
Practitioner-investigators (P-Is) invited the enrollment of all patients seeking care at participating practices who had undergone primary endodontic therapy and restoration in a permanent tooth three to five years earlier. P-Is classified endodontically reated teeth as restorative failures if the restoration was replaced, the restoration needed replacement or the tooth was cracked or fractured.
P-Is from 64 practices enrolled in the study 1,298 eligible patients who had endodontically treated teeth that had been restored. The mean (standard deviation) time to follow-up was 3.9 (0.6) years. Of the 1,298 enrolled teeth, P-Is classified 181 (13.9 percent; 95 percent confidence interval [CI], 12.1-15.8 percent) as restorative failures: 44 (3.4 percent) due to cracks or fractures, 57 (4.4 percent) due to replacement of the original restoration for reasons other than fracture and 80 (6.2 percent) due to need for a new restoration. When analyzing the results by means of multivariate logistic regression, the authors found a greater risk of restorative failure to be associated with canines or incisors and premolars (P = .04), intracoronal restorations (P < .01), lack of preoperative proximal contacts (P < .01), presence of periodontal connective-tissue attachment loss (P < .01), younger age (P = .01), Hispanic/Latino ethnicity (P = .04) and endodontic therapy not having been performed by a specialist (P = .04).
These results suggest that molars (as opposed to other types of teeth), full-coverage restorations, preoperative proximal contacts, good periodontal health, non-Hispanic/Latino ethnicity, endodontic therapy performed by a specialist and older patient age are associated with restorative success for endodontically treated teeth in general practice.
These results contribute to the clinical evidence base to help guide practitioners when planning the restoration of endodontically treated teeth.
Aim
Many challenges are faced during opening cavity access through crowns. This study aimed to present a novel design for a full-coverage crown to overcome the difficulties of opening endodontic access and to facilitate root canal treatment.
Methodology
This study comprised two parts: (I) the survey, a cross-sectional questionnaire-based survey was conducted among dentists to assess the degree and type of challenges, complications and difficulties of opening the endodontic access cavity through zirconia and porcelain-fused-to-metal (PFM) crowns, and (II) the experiment, a novel crown design that include a mark occlusally as a guide to access precisely into the pulp chamber was fabricated by taking cone-beam computed tomography scans along with digital impressions of teeth prepared to receive zirconia crowns. The scans were merged with the digital impressions to detect the exact location of the pulp chamber and to make a guide on the crown over the pulp. Subsequently, the crowns were cut using a computer-aided design/computer-aided milling machine. Twenty-one samples in three equal groups (control 1, natural teeth; control 2, full zirconia crowns; and the experimental group, the novel design) were accessed by one operator. The following criteria were evaluated: time spent, quality, and size of the access cavity. The data were collected and analyzed using the SPSS software program at a significance level of P-value < 0.05.
Results
In total, 440 dentists from 28 countries participated in this survey. Generally, the participants reported moderate and difficult degrees of opening through crowns. The most reported challenges and complications were the time spent in the opening and the fracture or chipping of the crown material. For the experiment, no significant difference was found among the groups in relation to the time spent for opening (P = 0.57), with the least required time of access for the experimental group. In addition, no significant difference was found in the quality and size of the access cavity (P = 0.775) among the groups.
Conclusion
Endodontic cavity access through zirconia and PFM crowns is difficult and time-consuming. The novel proposed design utilizing digital dental technology can overcome these issues by preserving the crown, decreasing chair time, and providing less complicated treatment.
Studies suggest that endodontic access cavity (EAC) can decrease the retention of crowns. However, there is no clear evidence that restoring EAC effects on crown retention. Thus, the main objective of this narrative
review is to assess several materials applied for restoring EAC to different crowns in anterior or posterior teeth, as well as the effect of each material on crown retention. An electronic search for studies published
until December 31, 2021, was conducted using the four databases: Scopus, PubMed, Web of Science, and Google Scholar. Researchers selected in vitro studies that investigated the crown retention before and after resorting EAC of anterior or posterior teeth. Exclusively, in vitro studies were considered for assessment. Five papers were selected for the final analysis from the 126 identified during the initial search. Our
outcomes illustrated that no significant differences in outcomes between the restorative materials after the endodontic treatment. The findings of this narrative review suggest that crown retention can increase after restoring endodontic access cavities. Finally, the available data indicated that restoring EAC could increase the crown retention more than the original crown. Nevertheless, the prefabricated crown resistance could be more affected by the type of restorative material used inside the EAC following endodontic treatment
than retention. Additional clinical and radiological measures are needed.
Purpose:
To: (1) determine which preparation techniques clinicians use in routine clinical practice for single-unit crown restorations; (2) test whether certain practice, dentist, and patient characteristics are significantly associated with these techniques.
Materials and methods:
Dentists in the National Dental Practice-Based Research Network participated in a questionnaire regarding preparation techniques, dental equipment used for single-unit crown preparations, scheduled chair time, occlusal clearance determination, location of finish lines, magnification during preparation, supplemental lighting, shade selection, use of intraoral photographs, and trimming dies. Survey responses were compared by dentist and practice characteristics using ANOVA.
Results:
Of the 2132 eligible dentists, 1777 (83%) responded to the survey. The top two margin configuration choices for single-unit crown preparation for posterior crowns were chamfer/heavy chamfer (65%) and shoulder (23%). For anterior crowns, the most prevalent choices were the chamfer (54%) and the shoulder (37%) configurations. Regarding shade selection, a combination of dentist, assistant, and patient input was used to select anterior shades 59% of the time. Photographs are used to communicate shade selection with the laboratory in about half of esthetically demanding cases. The ideal finish line was located at the crest of gingival tissue for 49% of respondents; 29% preferred 1 mm below the crest; and 22% preferred the finish line above the crest of tissue. Average chair time scheduled for a crown preparation appointment was 76 ± 21 minutes. Practice and dentist characteristics were significantly associated with margin choice including practice type (p < 0.001), region (p < 0.001), and years since graduation (p < 0.001).
Conclusions:
Network dentists prefer chamfer/heavy chamfer margin designs, followed by shoulder preparations. These choices were related to practice and dentist characteristics.
Dentists should make their clinical decisions based on the best evidence available. In recent years, training in evidence-based dentistry (EBD) has been incorporated into undergraduate dental curricula to aid students in their clinical practice. However, implementation of an evidence-based practice (EBP) by dentists is very limited, especially in the field of restorative and prosthetic dentistry. Therefore, the aim of this research project was to identify and find a solution for barriers preventing EBP implementation. To identify the EBP implementation barriers, we designed and applied a paper format self-administered questionnaire on dental undergraduate and graduate students. In order to find a solution for the lack of EBP implementation, we conducted a systematic review oriented to clinical practice which extracted the data of the available literature on the survival of single-unit crowns and dental fillings performed on posterior permanent teeth. Our results demonstrated that less than two in ten students base their restorative treatment-planning on the best available evidence and this may be due to students taking too long to find an answer to the clinical question and the difficulties in identifying the best available evidence for each specific scenario. Therefore, we conducted a systematic review to facilitate EBD in restorative treatment-planning. Our systematic review showed that the more the remaining tooth structure is available, the lower the failure rate among restorative treatments. It also suggested that vital teeth with two or fewer walls left should be restored with crowns, whereas teeth with more tooth structure should be restored with dental fillings, preferably amalgam restorations. Non-vital teeth with two or fewer walls left should be treated with crowns with post and core, whereas those with more tooth structure should be treated only with crowns. The restoration of non-vital teeth with less than a wall remaining has to be reconsidered since they have very high risk of failure. In conclusion, findings from this project indicate that dental students rarely apply EBD principles into practice and the main barrier preventing EBP implementation was lack of time. Therefore, the strategy proposed in this project was to provide easily accessible evidence-based knowledge in order to facilitate restorative treatment-planning based on the best evidence. Our knowledge synthesis results showed the areas of weakness in the restorative and prosthetic dentistry literature, either by high-risk of bias or lack of information, to address many of the restorative clinical scenarios that dental students and clinicians encounter for decision-making. This work could also serve as a foundation for future development of clinical guidelines in restorative and prosthetic
dentistry.
Statement of problem:
No knowledge synthesis exists concerning when to use a direct restoration versus a complete-coverage indirect restoration in posterior vital teeth.
Purpose:
The purpose of this systematic review was to identify the failure rate of conventional single-unit tooth-supported restorations in posterior permanent vital teeth as a function of remaining tooth structure.
Material and methods:
Four databases were searched electronically, and 8 selected journals were searched manually up to February 2015. Clinical studies of tooth-supported single-unit restorative treatments with a mean follow-up period of at least 3 years were selected. The outcome measured was the restorations' clinical or radiological failure. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, the Cochrane Collaboration procedures for randomized control trials, the Strengthening the Reporting of Observational Studies in Epidemiology criteria for observational studies, 2 reviewers independently applied eligibility criteria, extracted data, and assessed the quality of the evidence of the included studies using the American Association of Critical Care Nurses' system. The weighted-mean group 5-year failure rates of the restorations were reported according to the type of treatment and remaining tooth structure. A metaregression model was used to assess the correlation between the number of remaining tooth walls and the weighted-mean 5-year failure rates.
Results:
Five randomized controlled trials and 9 observational studies were included and their quality ranged from low to moderate. These studies included a total of 358 crowns, 4804 composite resins, and 303582 amalgams. Data obtained from the randomized controlled trials showed that, regardless of the amount of remaining tooth structure, amalgams presented better outcomes than composite resins. Furthermore, in teeth with fewer than 2 remaining walls, high-quality observational studies demonstrated that crowns were better than amalgams. A clear inverse correlation was found between the amount of remaining tooth structure and restoration failure.
Conclusions:
Insufficient high-quality data are available to support one restorative treatment or material over another for the restoration of vital posterior teeth. However, the current evidence suggests that the failure rates of treatments may depend on the amount of remaining tooth structure and types of treatment.
Background:
The objectives of this study were to quantify practitioner variation in likelihood to recommend a crown and test whether certain dentist, practice, and clinical factors are associated significantly with this likelihood.
Methods:
Dentists in The National Dental Practice-Based Research Network completed a questionnaire about indications for single-unit crowns. In 4 clinical scenarios, practitioners ranked their likelihood of recommending a single-unit crown. The authors used these responses to calculate a dentist-specific crown factor (range, 0-12). A higher score implied a higher likelihood of recommending a crown. The authors tested certain characteristics for statistically significant associations with the crown factor.
Results:
A total of 1,777 of 2,132 eligible dentists (83%) responded. Practitioners were most likely to recommend crowns for teeth that were fractured, cracked, or endodontically treated or had a broken restoration. Practitioners overwhelmingly recommended crowns for posterior teeth treated endodontically (94%). Practice owners, practitioners in the Southwest, and practitioners with a balanced workload were more likely to recommend crowns, as were practitioners who used optical scanners for digital impressions.
Conclusions:
There is substantial variation in the likelihood of recommending a crown. Although consensus exists in some areas (posterior endodontic treatment), variation dominates in others (size of an existing restoration). Recommendations varied according to type of practice, network region, practice busyness, patient insurance status, and use of optical scanners.
Practical implications:
Recommendations for crowns may be influenced by factors unrelated to tooth and patient variables. A concern for tooth fracture-whether from endodontic treatment, fractured teeth, or large restorations-prompted many clinicians to recommend crowns.
Objectives
Through a critical review of the most recent literature about fixed prosthesis on natural pillars, the authors discuss the quantification of permanent biological damage of the teeth used as prosthetic abutments.
Materials and methods
In cases of traditional fixed prosthetic rehabilitation, preparation of the natural elements that serve as a pillar inevitably shapes an irreversible injury of the coronal hard tissues, recognized by the customary forensic evaluation even if in the absence of specific tabular values. However, what is not taken into account usually is the share of permanent biological damage resulting from the reprocessing of stumps needed for a new prosthetic rehabilitation, whether it is a future renewal in civil liability cases or a remake of structure considered incongruous in professional liability cases. The physiological changes of the periodontal tissues of the tooth, resulting in a progressive exposure of the prosthetic margin and of the root tissue, or the design of a prosthetic device with overhanging margins and incongruous emergency profiles require the clinician to re-prepare the abutment before the implementation of the new manufacture.
Results
The loss of dental hard tissue caused by multiple prosthetic filings correlates with a progressive reduction in the size of the abutment, with its consequent weakening and exposure to an increased risk of fracture. This condition inevitably affects the degree of survival of the corresponding prosthetic device, which must be replaced by a prosthesis longer than the previous one, or even another type of prosthesis, if not more repeatable with the same characteristics.
Conclusions
The irreversible loss of dental tissue resulting after prosthetic reprocessing makes necessary an adequate medicolegal evaluation of the damage, which aims to identify the clinical expression of the injury and resulting impairment in its fullness.
Dental erosion is increasing, and only recently are clinicians starting to acknowledge the problem. A prospective clinical trial investigating which therapeutic approach must be undertaken to treat erosion and when is under way at the University of Geneva (Geneva Erosion Study). All patients affected by dental erosion who present with signs of dentin exposure are immediately treated using only adhesive techniques. In this article, the full-mouth adhesive rehabilitation of one of these patients affected by severe dental erosion (ACE class IV) is illustrated. By the end of the therapy, a very pleasing esthetic outcome had been achieved (esthetic success), all of the patient's teeth maintained their vitality, and the amount of tooth structure sacrificed to complete the adhesive full-mouth rehabilitation was negligible (biological success).
To determine Kaplan-Meier survival estimates and Weibull lifetime predictions for four all-ceramic crown systems from long-term data (> 5 yrs).
Single unit crowns of Cerestore (n = 30), Dicor (n = 30), Hi-Ceram (n = 22) and In-Ceram (n = 68) were placed in 95 patients treated in a university clinic. They were cemented using glass-ionomer (GI) for Cerestore, zinc phosphate (ZP) for Dicor, and 75% ZP (n = 51), 20% GI (n = 13) and 5% resin-based cement (n = 4) for In-Ceram crowns. The follow-up times were 8 yrs for Cerestore, 7 yrs for Dicor, 6 yrs for Hi-Ceram and 5 yrs for In-Ceram. The statistical analyses were based on censored data sets. A progressively censored Weibull distribution allowing for lifetime predictions beyond the actual observation time was used as well as the Kaplan-Meier Survival Product Limit Estimate (PLE), which provides survival estimates up to the maximum time of follow-up.
Cerestore, Dicor and Hi-Ceram demonstrated molar fractures in the first 2 yrs, whereas for In-Ceram these occurred during the third and fourth year of the study. The Kaplan-Meier Survival PLE was 69% for Cerestore at 8 yrs, 86% for Dicor at 7 yrs, 81% for Hi-Ceram at 6 yrs, 92% for In-Ceram at 5 yrs. The predicted Weibull characteristic time T0 (time at which 63% of the restorations would have failed) was 23 yrs for Cerestore, 34 yrs for Dicor, 31 yrs for Hi-Ceram, and 16 yrs for In-Ceram. However, when using data sets arbitrarily limited to the three first years of follow-up, T0 decreased significantly for Cerestore, Dicor and Hi-Ceram due to the number of early fractures. Such Weibull lifetime data illustrate the risk of predicting long-term (> 5 yrs) survival using short-term (< or = 3 yrs) data on ceramic restorations, which exhibit fracturing in the initial years.
This study compared the influence of two luting cements on the clinical performance of single crowns.
Twenty patients received 39 pairs of metal-ceramic and Procera crowns cemented with zinc phosphate and resin-modified glass-ionomer luting cement (Vitremer) in a split-mouth randomized pattern blinded to the recipient. The crowns were examined immediately after cementation, after 2 weeks, after 6 months, and then yearly. Clinical performance was scored according to CDA criteria, Silness and Loe criteria, patient satisfaction, and operator-appraised general clinical criteria. Three clinicians in private general practice carried out all procedures.
During the observation period, which varied between 80 and 104 months, seven clinical events were recorded. Two abutments fractured vertically, two underwent retrograde endodontic surgery, and one developed pulp necrosis. Two crowns were recemented. Estimated survival, defined as no negative events observed, was 89% at 102 months (85% for crowns cemented with zinc phosphate and 93% for crowns cemented with resin-modified glass-ionomer). Estimated survival, defined as no recementation or loss of pulp vitality, was 96% at 102 months (95% with zinc phosphate and 97% with resin-modified glass-ionomer). The differences between cements were not statistically significant.
A resin-modified glass-ionomer luting cement was at least as good as zinc phosphate cement to retain single crowns over a 102-month observation period.
The purpose of this study was to compare the longevity of crowns versus large multisurface restorations in posterior teeth. The investigation used the treatment database at Virginia Commonwealth University School of Dentistry. The inclusion criteria for the final data set used for analysis were: only one restored tooth per patient, premolars with three or more restored surfaces, molars with four or more restored surfaces, molars and premolars restored with complete veneer metal crowns, or crowns veneered with metal and porcelain. The Kaplan-Meier approach was used to visualize the survival curves, and the Cox proportional hazards model was used for analysis of predictor variables. The investigation indicates crowns survive longer than large restorations and premolar restorations survive longer than molar restorations. The median survival for crowns exceeded 16.6 years, with the median survival of premolar restorations being 4.4 years and molar restorations 1.3 years. An interaction between age and treatment was discovered, with overall survival decreasing as patient age increases. The doctor supervising the treatment also affected survival with treatment supervised by specialists lasting longer than treatment supervised by nonspecialists.
Purpose A leucite-reinforced, glass-ceramic material was recently introduced for clinical use. In this clinical trial, IPS-Empress material was tested in the form of full-porcelain crowns.
Materials and Methods Thirty-four patients were restored with 78 full-porcelain crowns. After etching the crowns with hydrofluoric acid, they were silanized and luted using dentin bonding agents and resin composite cement, which was primarily a dual-cured type. The 41 anterior and 37 posterior crowns were evaluated clinically with a mirror and probe, radiographically, and using clinical photographs, according to the modified United States Public Health Service criteria. Restorations having neither charlie nor delta criteria were defined as successful, and their survival rate was calculated according to Kaplan-Meier analysis.
Results The mean observation period for the 78 restorations was 19.7 ± 8.5 months. Seventy-four crowns were defined as successful. Four restorations failed because of fractures. Three of the four failures occurred in the first 2 months after cementation. The survival rate was estimated to be 95% successful after 2 years in service. Eighty percent of the crowns demonstrated an excellent esthetic result.
Conclusions The initial clinical results of this esthetic full-porcelain crown system are encouraging. However, because of fatigue phenomena for all ceramic materials, a longer observation period is needed to provide a definitive prognosis about the long-term clinical behavior.
Thirty-three castable apatite ceramic crowns were constructed for 26 patients. The crowns were clinically evaluated for anatomic form, marginal adaptation, cavosurface marginal discoloration, surface roughness, and color match for a period of 2 years at regular intervals. Results showed that all restoration had satisfactory anatomic form; all but one exhibited good marginal adaptation. Slight abrasion was noticed at the functioning cusps and all but three of the restorations demonstrated excellent color matching.
The longevity of 1,207 restorations placed by students was studied in 70 adult patients. The overall percentage of restorations lasting ten years or more (P10) was 75.4 percent and survival times were longer than in most previous restoration longevity studies. Cast restorations lasted significantly longer than amalgams, which in turn lasted significantly longer than composites. P10 values were 91.1 percent, 72.0 percent, and 55.9 percent, respectively. Analysis by surfaces involved indicated that single-surface lasted longer than multisurface restorations. The survival of restorations placed in patients aged 60 or more was less favorable (P10 = 56.8 percent) than for younger patients (P10 = 78.3 percent). A subset of the population was identified on the basis of a restoration failure rate of greater than 4.0 X 10(-2) failures/restoration year. This group, comprising 18.6 percent of the population, accounted for 56.1 percent of all restoration failures. The P10 value for this high-risk group was 55.8 percent, as compared with 83.9 percent for the remainder of the population.
In this article the results are presented of an evaluation of crowns and bridges in a general practice. The study includes 601 solitary crowns, 213 crowns on bridge abutments and 103 crowns on RPD abutments. In total eighty-four bridges were examined. All these restorations were constructed during a period of 11.5 years. By means of the Kaplan-Meier method a prognosis is given of the life span of the different solitary crown-types over periods between 1 and 11 years. The total amount of failures and follow-up treatments on bridge and RPD abutments was very small. The authors also examined whether the bridges were constructed according Ante's law. A follow-up of this study in other Dutch general practices in combination with experimental clinical trials is under way.
The clinical outcome of 95 consecutively placed In-Ceram complete coverage crowns, 68 posterior and 28 anterior, all luted with conventional cements, was studied. In the 56 month observation period no total failure requiring replacement of a restoration occurred. The veneer of a molar single crown fractured, while its ceramic core remained intact. With four crowns, marginal caries was observed after 2-4.5 years. It was concluded from this clinical study that In-Ceram complete coverage all-ceramic crowns are indicated for anterior and posterior teeth.
There is very little information available from private dental practices on the comparative survivals of extensive posterior amalgam restorations and posterior crowns placed in the same patient population. Therefore, the present retrospective study examined the performance of such restorations at three long-established Adelaide city practices.
Life-table survival estimates were generated for 160 extensive amalgams, 96 cast gold crowns and 174 ceramometal crowns. The restorations were placed by 20 dentists at various times in 100 patients who attended the practices on a regular basis for around 25 years on average.
There were no significant differences found in the survival times for both types of crowns, with around 70% still being present at 20 years. However, the median survival time for the extensive amalgams was much lower, at 14.6 years. Despite these differences in survival times, the extensive amalgam restorations survived for longer than is usually expected.
In this present study, the survival findings have implications for the most cost-effective dental treatments of large lesions in posterior teeth.
For 4735 posterior complex amalgams and crowns placed in adults with continuous dental HMO coverage, all additional treatment received over the subsequent 5 years was determined. The restorations were placed under routine clinical conditions by 74 different dentists among a broad spectrum of insured dental patients. Treatment outcomes were described in terms of a hierarchical classification of additional treatments. At the extremes, a successful outcome was defined as no additional treatment or an additional one- or two-surface restoration on the same tooth, and a catastrophic outcome as extraction or endodontic treatment. Due to clinical protocols, teeth with guarded to poor prognosis prior to treatment are overrepresented in the five-surface amalgam cohort. Successful outcomes characterized 72% of four-surface amalgams, 65% of five-surface amalgams, 84% of gold crowns, and 84% of porcelain crowns. Catastrophic outcomes occurred for 10% of four-surface amalgams, 15% of five-surface amalgams, 8% of gold crowns, and 9% of porcelain crowns.
The IPS Empress pressed glass-ceramic system was used in this investigation to restore anterior and posterior single teeth. One hundred forty-four crowns were evaluated over a period of 6 to 68 months (mean period of 37 months). According to the Kaplan-Meier analysis, the estimated success rate after this period was 95.35%. Crowns were also investigated using the modified US Public Health Service criteria. Most of the crowns rated as Alpha for color match, contour, marginal integrity, recurrent caries, and marginal discoloration. The results of this study indicate that this material can be successfully used, especially in the anterior area, when the procedures outlined are carefully followed.
The purpose of this study was to retrospectively evaluate leucite reinforced-glass ceramic crowns (Empress) placed in patients who regularly visit general practices.
One hundred ten Empress crowns, placed in 29 patients who visited a general practice on a regular basis, were evaluated according to the California Dental Association's (CDA) quality evaluation system. In addition, the occurrence of plaque and certain gingival conditions was evaluated. All crowns were luted with resin composite cement. The mean and median years in function for the crowns were 3.6 and 3.9 years, respectively.
Based on the CDA criteria, 92% of the 110 crowns were rated "satisfactory." Eighty-six percent were given the CDA rating "excellent" for margin integrity. Fracture was registered in 6% of the 110 crowns. Of the remaining 103 crowns, the CDA rating excellent was given to 74% for anatomic form, 86% for color, and 90% for surface. No significant differences (P > 0.05) were observed regarding fracture rates between anterior and posterior crowns. With regard to the occurrence of plaque and bleeding on probing, no significant differences (P > 0.05) were observed between the Empress crowns and the controls.
Most of the fractured crowns had been placed on molars or premolars. Although the difference between anterior and posterior teeth was not statistically significant with respect to the fracture rates obtained, the number of fractured crowns placed on posterior teeth exceeded that of those placed on anterior teeth. The difference between the fracture rates may have clinical significance, and the risk of fracture has to be taken into consideration when placing crowns on teeth that are likely to be subjected to high stress levels.
Alternatives to metal-ceramic restorations should possess clinical durability before being recommended to the dentist. Longitudinal clinical studies are required for evaluation so innovative types of restorations can meet the expectations of dentists and patients.
This study compared the performance of galvano-ceramic restorations (Auvo Galvano Crown [ACG]) and glass-ceramic individual crowns (Dicor) based on longitudinal clinical trials.
A total of 769 galvano-ceramic single crowns (AGC) in 322 patients and 173 glass-ceramic individual crowns (Dicor) in 88 patients were reviewed for 8 years and a maximum of 11 years, respectively, after cementation. Risk of fracture was determined with use of a survival analysis (Kaplan and Meier).
Partial ceramic cracking was observed at the time of the last recording of data in 11 galvano-ceramic crowns, 8 of the units remained in place. Two crowns became dislodged and 1 tooth exhibited a fractured root, despite an intact crown. One restoration was removed because of hypersensitivity and 1 with partial ceramic fracture. Forty-two of the glass-ceramic crowns were completely fractured. After a comparable 7 years under risk, 96.5% (+/-3.4; 95% confidence interval) of the galvano-ceramic premolar and molar crowns and 92% (+/- 8.5) of crowns placed on incisors and canines crowns were intact. The corresponding data for the glass-ceramic restorations were only 70% (+/- 10.6) in posterior and 82.7% (+/- 8. 1) in anterior quadrants.
Long-term results of electroformed individual crown restorations were superior to glass-ceramic restorations.
The biocompatibility of titanium has been well documented, but clinical outcomes of ceramic-veneered titanium restorations were not conclusive.
The study presents the results of a 5-year clinical study of individual crowns and fixed partial dentures (FPDs) veneered with a low-fusing ceramic of the Procera system.
All patients at one clinic who required crowns or FPDs during a 2-year period were invited to participate. A total of 260 patients received 333 ceramic-veneered Procera restorations (242 single crowns and 91 FPDs). Clinical registrations were performed annually, and the restorations were evaluated according to the California Dental Association rating system. At the 5-year follow-up, 198 (76%) patients were examined. Most of the loss of patients could be explained.
Practically all Procera restorations were judged as satisfactory both at baseline and follow-up examinations. One artificial crown and 1 FPD were remade because of extensive fractures of ceramic veneers. Two FPDs had fractures of a soldered joint, but only 1 FPD was replaced. Some minor complications occurred, such as small porcelain fractures that could be polished (6% of single crowns, 13% of FPDs) and or loosened restorations that were recemented. Other recorded complications were not related to the Procera system but to dental caries, loosened posts and cores, and root fractures.
Clinical outcomes over a 5-year period for ceramic-veneered titanium restorations with the Procera system were favorable.
There are few in vivo studies on the clinical performance of all-ceramic crowns.
The aim of this study was to evaluate the clinical performance of IPS Empress crowns.
Thirty-seven all-ceramic IPS Empress crowns were placed in 20 patients. Twenty crowns were luted with Variolink II low-viscosity resin cement in combination with Syntac Classic dentin adhesive; the remaining 17 were luted with Variolink II in combination with Syntac Single Component. All procedural steps were performed by the same prosthodontist. Using the California Dental Association's (CDA) quality evaluation system, 2 calibrated evaluators examined the crowns for margin integrity, anatomic form, surface, and color for a period of 12 to 41 months, with a mean of 24.56 months after insertion. Kaplan-Meier statistical analysis was used to calculate the survival rate of the crowns. Values obtained for plaque and gingival conditions were compared to control teeth with use of the Wilcoxon signed ranks test (P<.05).
Based on the CDA criteria, 94.6% of the crowns were rated satisfactory. Fracture was registered in only 1 crown. One endodontically treated tooth failed due to the dislodgement of the prefabricated dowel. No significant difference was observed in the gingival health status of crowns that had margins placed above or at the level of the gingival margin. However, in crowns that had subgingival margin finish lines, the percentage of bleeding on probing was significantly higher than that of the contralateral control teeth.
In this in vivo study, IPS Empress crowns luted with both dentin bonding agents functioned satisfactorily with a relatively low fracture rate over a mean evaluation period of 24.56 months.
The authors compare patterns of oral health care reported by the Washington Dental Service, or WDS, Seattle, in 1993 and 1999 to assess changes in patient populations, practice characteristics, procedures and treatment costs in the state.
Data were obtained from dental benefits claims from a population of about 1.25 million people. Variables of interest included patient age and other demographic information, character of dental practice, dental procedures and treatment costs that combined WDS payment and patient copayment.
The results showed high agreement (97 percent) between the database and randomly surveyed patient records. For both 1993 and 1999, general dental offices were responsible for more than 80 percent of patient care. Single crowns (21 percent), restorative services (15 percent) and dental prophylaxis (13 percent) made up about half of the costs of dental care. Broad categories of service were similar in 1993 and 1999, and anticipated major declines in restorative procedures related to caries were not apparent. The mix of services varied considerably by patient age and between generalists and specialists in both years.
Patterns of oral health care among this insured patient population largely remained unchanged from 1993 to 1999, with some shifts in specific procedures and specialty care. During this period, dentists saw more patients and performed fewer treatments per patient, while total treatment costs per patient increased.
Patterns of oral health care in the United States are projected to undergo major changes linked to improved oral health, declining trends in caries and periodontal diseases, scientific advances in treatment approaches and a patient population that is living longer. Changes in care patterns during this six-year period may reflect patient and provider preferences, as well as the influence of reimbursement policies. Dental benefits databases can serve as a critical resource for monitoring such changes.
Prompted by increased patient requests for esthetic treatment, restorative clinicians have evaluated a variety of new materials and procedures. This study reports on 5 years' experience with In-Ceram Spinell all-ceramic crowns. A total of 40 anterior crowns were positioned in 13 patients from October 1995 to December 1998. The clinical examination was made following modified California Dental Association/Ryge criteria. Final evaluation was carried out in October 2000, for an observation period of 22 to 60 months (mean 50 months). Only one failure was recorded, and the fractured crown needed to be replaced; according to Kaplan-Meier analysis, the estimated success rate was 97.5%. A thorough description of the clinical procedures through which anterior teeth can be successfully treated with all-ceramic Spinell crowns is described.
Earlier studies on low-fusing ceramics have shown the occurrence of changes over time regarding surface and color. The present prospective study is an ongoing follow-up of an intraindividual comparison between two metal-ceramic systems, the Procera system (titanium copings veneered with a low-fusing ceramic) and noble-alloy copings veneered with a medium-fusing ceramic.
Twenty-one crown pairs were fabricated for 18 patients. After 5 years, 18 crown pairs in 15 patients were available for comparison. The crowns were examined shortly after cementation (baseline), and after 1, 2, and 5 years. The crowns were rated according to the CDA system. Bleeding index and margin index were also evaluated.
Obvious changes regarding surface and color were noted for the titanium-ceramic crowns. The difference between the two types of crowns was statistically significant at 5 years (P = .004). The differences between the two systems regarding anatomic form, margin integrity, bleeding index, and margin index were small.
Within the limitations of this study, it is concluded that low-fusing ceramic-veneered titanium copings are inferior to medium-fusing ceramic-veneered conventional copings regarding surface and color of the ceramic. Therefore, conventional ceramic-veneered crowns seem to be preferable, at least in the anterior area, where the esthetic requirements are greater than in premolar and molar regions. Whether possible changes in the properties of low-fusing ceramics will reduce the differences between the two types of metal-ceramic crowns remains to be proven.
The venerable PFM crown or fixed prosthesis still dominates the tooth-colored restoration market. However, use of PFMs is declining slightly, as the many new all-ceramic and resin-based composite crowns and fixed-prosthesis products flood the market. Several situations may indicate the use of materials other than PFM. They include patients requiring a high level of esthetic acceptability, patients with proven or perceived allergies to the metals used in dentistry and bruxing or clenching patients with metal allergies or desire to eliminate metal from their mouths. PFM restorations have been proven during 40 years of successful use. They provide acceptable esthetics for most situations, minimal fracture during service, proven ability to serve in multiple-unit situations and excellent fit, and the profession has detailed knowledge of these restorations' advantages, disadvantages and physical characteristics. PFM restorations have only a few well-known negative characteristics. Be cautious as you elect to move from the reliability and positive history of PFM to relatively unknown types of restorations.
The aim of this article was to study frequencies and distribution of remakes of all-ceramic inlays/onlays, veneers, and crowns occurring before and after cementation.
A total of 2,069 sintered feldspathic ceramic restorations (Colorlogic) and 1,136 pressure-molded ceramic restorations (IPS Empress 1 and 2) were produced during the study period by one dental laboratory. The laboratory gave an unqualified and unlimited guarantee for their ceramic restorations. The outcome variable was reports from the clinicians to the dental laboratory about any problems related to the restoration, necessitating remake.
Problems occurring before cementation occurred in 4.4% of the restorations. Veneers were remade more frequently than the other types of restorations (6.6%). After cementation, the overall 2-year rate of remakes was 1%, indicating a survival rate of the ceramic restorations of 99%, with inlays/onlays exhibiting the highest (99.8%) and crowns the lowest (98.4%) rates. This difference in rates was significant. No significant differences in remakes between ceramics or tooth categories were found.
There were few problems in a short- to medium-term perspective that, in the opinion of general practitioners, necessitated remakes of all-ceramic restorations.
Crowns and large amalgams protect structurally compromised teeth to various degrees in different situations. The aim of this investigation was to evaluate the survival of teeth with these two types of restorations and the factors associated with better outcomes. Retrospective administrative and chart data were used. Survival was defined and modeled as: (1) receipt of no treatment and (2) receipt of no catastrophic treatment over five- and 10-year periods. Analyses included: Kaplan-Meier survival curves, Log-Rank tests, and Cox proportional hazards regression modeling. Crowns survived longer with no treatment and with no catastrophic treatment; however, mandibular large amalgams were least likely to have survived with no treatment, and maxillary large amalgams were least likely to have survived with no catastrophic treatment. Having no adjacent teeth also decreased survival. Crowns survived longer than large amalgams, but factors such as arch type and the presence of adjacent teeth contributed to the survival of large amalgams.
The purpose of this retrospective case study of dental records was to compare the long-term failure rates and modes for resin-bonded sintered feldspathic porcelain veneer crowns (RBPVCs) either containing or without metal substructure reinforcement.
Two prosthodontists placed 62 RBPVCs fabricated with, and 167 without, metal reinforcement in 143 older adolescent and adult patients treated in a private practice. Clinical judgement determined the type of crown design placed. Preparation margins were generally finished on enamel, and all crowns occluded with opposing teeth. Observations included the patients, operators, crown designs and failure modes. Chi-square or Fisher's exact tests and life table survival statistics were used to evaluate the findings (alpha = 0.05).
Over five years, failures occurred in 14.5% of RBPVCs fabricated with, and in 18.6% without, metal reinforcement. Cumulative survival estimates were 74.3 +/- 8.5(Standard Error)% and 72.9 +/- 4.8(SE)%, respectively (P = 0.96). Mandibular posterior crowns comprised 27.1% of the placements, but 47.5% of the failures. Bulk fracture of porcelain occurred in 7.0% of the crowns, all without metal reinforcement. Minor porcelain fractures and debonding were less frequent in both types of crowns. Persistent pulpitis occurred in 3.5% of all teeth.
There was a significant risk of failure for sintered porcelain RBPVCs placed as posterior restorations. Although metal reinforcement was able to reduce the risk of bulk fracture of porcelain, other causes of failure were less affected.
The aim of the study was to evaluate the clinical performance of Procera Alumina AllCeram crowns (Nobel Biocare).
In 70 patients, 61 anterior and 46 posterior teeth were provided with single crowns and cemented with a glass-ionomer cement.
Four patients were lost to follow-up. Six crowns had to be removed, all because of nonreparable fracture. At 6 years, the cumulative survival rate was 94.3% for all crowns, 96.7% for anterior crowns, and 91.3% for posterior crowns (survival = not removed). Most of the defects occurred within the first 1.5 years.
The findings indicate a good clinical prognosis of both anterior and posterior Procera Alumina crowns.
Clinical fees for crowns vary significantly. However, as with any clinical service, the quality of the treatment may or may not be related to the fee for the crown. Using PFM crowns as an example, I have discussed the difference in quality of service, boutique practices, third-party payers, the relationship of crown fees to crown longevity, the time involved for the crown procedure and laboratory costs. Dentists are advised to examine their practices to ensure that they are producing quality crown service at fees the public can afford.