Extra-coronal Restorations Research Articles

Quality of post and core placement by final year undergraduate dental students.

The success of endodontic restoration of badly compromised teeth depends on the quality of post and core placement and the extra-coronal restoration. Ensuring that students place posts to acceptable quality standards is therefore essential. The aim of this study was to radiographically evaluate post placement by final year undergraduate dental students and to identify any predictors of performance. Two hundred retrospectively and randomly selected posts placed by sixth year students were evaluated radiographically. Data on student gender; number and quality of radiographs; periapical pathology; tooth location; root canal treatment quality; amount of remaining gutta percha; gap between gutta percha and post; post-to-root width; crown-to-root ratio; and types of core material and crowns were recorded. Four criteria were used to grade post placement quality: (i) amount of remaining gutta percha; (ii) gap between gutta percha and post; (iii) post width to root ratio; and (iv) crown-to-root ratio. Assessments were scored to produce final grades. Data are presented using descriptive statistics and the chi-squared test was used to investigate whether student gender or tooth location were associated with final grade. Post and core quality was acceptable in most cases (97.5% were graded as adequate), with no differences in quality between male and female students nor according to tooth location (anterior, premolar, and molar). Just over half of radiographs were adequate quality (53.5%), while just under half were assessed as less than adequate (46.5%) due to cone cutting, overlap, shortening or elongation, although this did not affect formal assessment of post quality. General outcomes of post and core placement by undergraduate students were good, with few errors that might affect the prognosis and long-term survival of treated teeth. Providing undergraduate dental students with clear guidelines on when and how to take radiographs throughout the procedure may improve the quality of post and core treatment and reduce the risk of multiple unnecessary radiographic exposures. From the clinical perspective, although dental students generally place high quality posts and cores, it remains important to monitor the quality and performance of post placement as this determines the survival of compromised teeth.

Casting Machines in Dentistry - A Review Part I.

Dental casting machine is an electrical device used to extrude molten materials to fabricate dental prostheses such as crowns, bridges, intracoronal and extracoronal restorations, and removable partial dentures. The casting process basically include melting and casting. Firstly, the solid material is heated in a crucible in temperature-controlled conditions to melt the material to its smelled form. The dental casting process is a complex one with multifaceted steps and equipment. Different types of casting machines are available to produce heat using different sources and techniques. It includes Arc melting, Open flame casting, and Electrical resistance. Arc melting involves the application of an electric or gas discharge on tungsten electrodes, causing the metal base to melt utilizing the heat produced by arcing. Open flame casting or induction melting employs water-cooled alternate current induction coils to induce heat. However, resistance heating uses electric current to melt precious metals.

Digital evaluation of occlusal reduction of metal crown preparations in students in the COVID-19 era: A cross-sectional study

IntroductionOcclusion of extra-coronal restorations depends on the reduction achieved during crown preparation. Ensuring adequate reduction is therefore essential for the success of the final restoration. The objective of this study was to digitally quantify the occlusal reduction performed by preclinical undergraduate dental students and to compare their performance across the year and using a hybrid teaching approach developed because of the COVID-19 pandemic. MethodsEighty full metal crown preparations on typodonts were scanned using the KaVo Arctica 3D Optical scanner. Occlusal reduction was measured using Autodesk Fusion 360 v2.0 by superimposing an unprepared tooth over the preparation and taking measurements at six occlusal points (mesio-buccal (MB), disto-buccal (DB), mesio-lingual (ML), disto-lingual (DL), mesial fossa (MF), and distal fossa (DF)). A general linear model was used to compare student performance in the mid vs final year exams and in 2018/19 vs 2020/2021. ResultsThe adequacy of occlusal reduction was variable. Occlusal reductions of the MF (p = 0.014) and DF (p = 0.011) were significantly lower in the final exam than the mid-year exam in 2018/2019. There was also occlusal under-reduction at all six occlusal points in 2020/2021 compared with 2018/2019. ConclusionsStudents must be encouraged to use verification guides throughout the procedure to ensure adequate reductions. These verification methods can be as simple as putty indices or as advanced as optical scanners. The use of verification methods alongside a hybrid virtual and live teaching approach may guarantee the best results.

Different extra-coronal restoration options of hemisected teeth on structurally compromised mandibular molar: Report of two cases

Structurally compromised teeth tend to be extracted due to its their poor prognosis, however, hemisection may serve as an alternative option in selected cases. This case report is aimed to discuss two cases of hemisected mandibular molars with two different approaches for post-hemisection restoration. Case 1 presents with terminal tooth 37 diagnosed with a cracked tooth involving severe bone loss on the mesial root. The tooth was hemisected and restored with a mesially cantilevered full ceramic crown. Case 2 presents with root caries on an endodontically treated tooth 46 on a patient with bruxism, with an inadequate ferrule on the distal segment. The tooth was hemisected utilizing the socket preservation technique, and the tooth was restored with a conventional fixed-fixed bridge with a second abutment on tooth 47.

Trueness and surface characteristics of 3-dimensional printed casts made with different technologies

Statement of problemThree-dimensional (3D) printers should be capable of fabricating products with high accuracy for potential use in a wide range of dental applications. The trueness and surface characteristics of 3D-printed casts made with different technologies remain unclear. PurposeThe purpose of this in vitro study was to evaluate the trueness and surface characteristics of 4 types of dental casts printed using 6 different 3D printers. Material and methodsFour dental casts prepared for intracoronal and extracoronal restorations were printed using 6 different 3D printers—2 printers of each printing technology (FDM: Creator, Lugo; DLP: D2, ND5100; SLA: Form 2, Form 3). The printed casts were scanned to obtain standard tessellation language (STL) data sets that were superimposed onto the reference to evaluate their trueness (n=15). Trueness was measured based on overall deviations for each cast and for sectional deviations within the cavities. For qualitative evaluation, the surface characteristics of the 3D-printed casts were analyzed by using a digital camera, stereomicroscope, and scanning electron microscope. Statistical analyses were conducted using the Kruskal-Wallis test, followed by multiple Mann-Whitney U tests for pairwise comparisons among groups (α=.05). ResultsThe overall median trueness values were lowest with the Form 3 (27.9 μm), followed by the ND5100 (30.0 μm), Lugo (37.1 μm), D2 (41.4 μm), Form 2 (46.9 μm), and Creator (83.3 μm) (P<.05). Sectional deviations within the cavity were generally greater than overall deviation. Macroscopic and microscopic images showed that the reproduced casts had the smoothest surface with the SLA, followed by the DLP and FDM printers. Horizontal layers were more discernible with the FDM printer. ConclusionsThe trueness of the 3D-printed casts was influenced by the type of tooth preparation and was printer dependent. Among the tested 3D printers, the Form 3 produced the most accurate casts, while the Creator produced the least accurate casts.

Wear behavior of bonded occlusal veneers constructed from machine milled glass and polymer infiltrated ceramics in contact with enamel: An in vitro study

Statement of problem: Occlusal veneer is considered an extra-coronal restoration with less invasive preparation. Yet there is a shortage of information as regards the wear behavior of materials from which occlusal veneers are manufactured and their opposing enamel. Purpose: Evaluate the wear of bonded occlusal veneers constructed from two dissimilar materials along with their opposing enamel following chewing simulation. Material and Methods: 16 table tops of two dissimilar materials

Comparison of the Marginal Fit of Heat Pressed Crowns Fabricated With 3D Printed and Conventional Methods

Introduction: Marginal adaptation is one of the key factors in the success of dental crowns. It is necessary to identify marginal adaptation in order to determine the spacing and prevent the onset of diseases. This study sought to use 3D and manual printing methods aiming at manufacturing heat press full-coverage extra-coronal restorations with more marginal adaptation.&#x0D; Materials &amp; Methods: This study was conducted in the year 1397-98 at the Islamic Azad University of Isfahan using descriptive-analytical and cross-sectional method with 20 samples. Ten samples were evaluated using a 3D printing method, and ten samples were assessed by manual wax-up technique. Results were analyzed using Kruskal-Wallis and Mann-Whitney tests.&#x0D; Results: There was a significant difference between the restoration space and the marginal edges in eight parts of the teeth in the manual method (p value &lt; 0.001). The marginal edge space in the eight parts of the tooth was not significantly different in the 3D print method (p value = 0.614). A significant difference was observed in restoration space and the marginal edge between 3D printing and manual techniques (p value &lt; 0.001).&#x0D; Conclusion: The compatibility of the complete outer crowns of the heat press in the 3D printing method was not significantly different from the manual waxing method.

Comparison of Microleakage in Nanocomposite and Amalgam as a Crown Foundation Material Luted with Different Luting Cements under CAD-CAM Milled Metal Crowns: An In Vitro Microscopic Study.

Microleakage is a persistent problem despite advancement in materials and techniques in fixed prosthodontics. This leads to the importance of sound crown foundation material and luting agents used to maintain the marginal seal. The literature is deficient with studies, comparing microleakage under various crown foundation materials and luting agents, especially with CAD-CAM (computer-aided design and computer-aided manufacturing) metal crowns. This study was aimed to compare microleakage in a nanocomposite/dentinal bonding agent and amalgam/cavity varnish as crown foundation materials luted with two different luting cements: resin-reinforced glass ionomer cement and self-adhesive resin cement, under both dry and contaminated conditions. A hundred intact, caries-free human molars were prepared to receive crown foundation material and extra coronal restorations. Amalgams with cavity varnish and nanocomposites with dentinal bonding agent in both ideal and contaminated conditions were used as crown foundation materials. After restoration, each sample was cemented with a CAD-CAM milled metal crown using two different luting agents—resin-reinforced glass ionomer cement and self-adhesive resin cements both in ideal and contaminated conditions. Cementation was followed by thermocycling of samples, immersion in erythrosine B dye, embedding in clear auto polymerizing acrylic resin and sectioning to evaluate microleakage using stereomicroscope. The mean microleakage between different luting cements on the experimental side of the facial surface was 137.64 μm and 211.01 μm for resin-reinforced GIC and for self-adhesive resin cement was 119.78 μm and 150.42 μm, under ideal and contaminated condition, respectively. There was a significant difference in mean micro-leakage between different crown foundation material and cement groups used in the study. The composites and amalgam, both when used as crown foundation material and luted with use of technically advanced CAD-CAM metal crown with self-adhesive resin cement (in both ideal or contaminated condition), showed less microleakage than in resin-reinforced glass ionomer cement. Overall, the self-adhesive resin cement showed comparatively reduced microleakage in all combinations with different crown foundations. Thus, this combination can be used in daily clinical practice to provide better protection from further decay.

Comparative evaluation of compressive strength of three different core build up materials on fiber reinforced composite post after 24 hours and 1 week- an in vitro UTM study

Background: A core build-up is a restoration placed in a badly broken down tooth to restore the coronal portion of the tooth. This facilitates subsequent restoration of the broken down tooth by means of extra-coronal restoration. Compressive strength of core materials is thought to be important because core usually replaces the large bulk of the tooth structure and must resist multidirectional forces. In this study compressive strength of three different core materials was investigated on Fiber Reinforced Composite post at different time intervals. Objective: The purpose of the study undertaken was to determine the compressive strength of self-cured, photo cured and dual cured core build up materials on Fiber Reinforced Composite post after 24 hours and 1 week. Methodology: Cylindrical specimens measuring 6mm in height and 4mm in diameter were prepared using a machined plexiglass mold and core build up was done around the fiber post. Ten specimens were prepared in each group (n=30); Group A: Restorative Glass lonomer Cement-GC Gold, Japan; Group B: Light-cured composite-Magma NT, Prevest Denpro, USA and Group C: Dual-cure core-build up composite resin-Para Core, Coltene whaledent, USA, which were further subdivided into five specimens per group according to the time intervals of 24 hours and 1 week. Compressive strength was determined using a universal testing machine. The maximum load applied to fracture the specimens was recorded and compressive strength calculated in MPA. The data obtained was analyzed using parametric one way ANOVA test and Bonferroni post-hoc procedure. Results: The mean compressive strength was significantly higher (p

Esthetic and functional rehabilitation of mutilated maxillary anterior teeth: A case series

An endodontically treated anterior tooth requires extracoronal restoration when the tooth structure is weakened or lost due to caries, placement of previous restorations and/or discoloured. The reduced tooth structure makes retention of extracoronal restoration difficult. The purpose of post is to provide retention for the core restoration, which replaces lost coronal structure. This article describes restoration of mutilated maxillary anterior teeth by using cast post and core, followed by porcelain fused to metal restorations.

Evaluation of Cervical Margin Relocation for CAD/CAM Zirconia Crowns Using Different Composite Resin Materials and Cavity Designs: Marginal Gap and Microleakage

This study evaluated the effect of the material and the extension of the relocated margin on the marginal adaptation of the extra coronal restoration and microleakage at the tooth/resin interface after thermo-mechanical cyclic loading. Materials and methods: 196 teeth were divided into six groups according to type of cavity design and build-up restoration. All the groups received a standardized MO cavity preparation. The gingival seat was located 2 mm above the CEJ. Group I was without any modification and restored with direct composite. For Group II, III and IV the gingival seat extended 2mm below the CEJ and restored with direct, flowable, indirect composite respectively. Group V had MOD cavity where the proximal boxes had the same criteria of the mesial preparation of Groups II-IV. Samples of Group VI received the same preparation as Groups II, III and IV but was extended another 4mm in the buccal direction. Groups V and VI were restored with direct composite. Margin gap and microleakage scores were evaluated after cyclic loading Results: Group VI and IV showed the highest mean margin value compared to different cavity designs and materials used for CMR respectively, however within clinically acceptable range. Group III showed the highest microleakage scores. Conclusions: The use of CMR with single or multiple narrow cavities is more favorable than with wide cavities. CMR is a logical option in teeth with deep proximal cavities that needs to be crowned.

Evaluation of the Marginal Location and Periodontal Health in Crowns and Bridges – A Patient Preference Based Study

OBJECTIVE: The objective of this paper was to evaluate the marginal location preference and periodontal health in extra coronal restoration of anterior and posterior teeth. METHODOLOGY: In this prospective case control study, a total of 652 patients who had crown and bridge for not less than six months were included. The gingival margin location preference and reasons behind choosing a particular gingival margin was asked from the patients. Additionally, the teeth with and without restoration were also examined for periodontal health. Split mouth technique was used as unrestored, healthy contra lateral teeth in the same individual served as controls. Descriptive statistics and Chi square test were used for analysis to formulate the results. RESULTS: Ironically, 92% patients were not given a chance by their dentist to give input about margin location preference. The majority of patients preferred equi gingival margin for their anterior crowns 495 (75.92%) and supra gingival margin 586 (89.87%) for their posterior teeth, with esthetics 547 (83.89%) and hygiene 599 (91.87%) respectively being the most common reasons for selecting the particular margin location. The clinical examination revealed that supra gingival and equi gingival margins demonstrated superior gingival health indices as compared to subgingival margins CONCLUSION: This study concluded that the supra gingival and equi gingival margins demonstrated superior gingival health indices as compared to subgingival margin and in order to achieve optimal periodontal health and patient satisfaction the health professionals should wisely consider the margin location and involve the patient in treatment decisions wherever possible. KEY WORDS: Crown and Bridge, Margin location, Patient preference, Periodontal Health.

Evaluation of the Clinical, Child, and Parental Satisfaction with Zirconia Crowns in Maxillary Primary Incisors: A Systematic Review.

Background With the increasing demand for aesthetics in children and their parents, the treatment of decayed primary anterior teeth is one of the biggest challenges in pediatric dentistry. Zirconia crowns have provided a treatment alternative to address the aesthetic concerns and ease of placement of extracoronal restorations on primary anterior teeth. Methods The electronic databases including PubMed, Scopus, Google Scholar, and Embase were searched on articles published between January 2010 and January 2021. Studies relating to evaluating the clinical success and satisfaction of both parents and children about zirconia crowns in maxillary primary incisors were reviewed. Results Nine studies met the criteria for final inclusion. Findings from these studies showed that parental and child satisfaction with zirconia crowns is high with clinically acceptable restorations in the maxillary primary incisors. Conclusion Parental and child satisfaction with zirconia crowns is high with clinically acceptable restorations in the maxillary primary incisors. In addition, larger sample sizes and longer follow-ups are required in future studies.

A Technique to Fabricate a New Crown to an Existing Removable Partial Denture.

Fabricating a crown for a tooth that serves as an abutment for an existing removable partial denture (RPD) provides a restorative challenge. Typically, the compromised tooth requiring an extra-coronal restoration is initially restored. It is followed by the construction of a new RPD that accurately fits the restored abutment. An increasingly common scenario is that the existing RPD is deemed clinically acceptable and, therefore, does not require replacing. This results in the clinical dilemma of fabricating a crown for an abutment tooth, while also considering how the contours of this restoration will fit with the RPD's clasps and rests. This can be achieved through the use of various techniques subdivided into indirect, direct and combined indirect-direct. This article describes an indirect-direct technique used in conjunction with the functionally generated path technique to achieve accurately a stable record of the patient's occlusion in the fabrication of a new crown to an existing RPD.

Treatment concepts for restorations of endodontically treated teeth: Survey of dentists in Jeddah city, Saudi Arabia

Introduction: Practices followed by dentists for restoring endodontically treated teeth (ETT) vary with a variety of available techniques and materials for post- and-core restorations. The aim of this study was to identify concepts for restoring ETT among dentists in Jeddah, Saudi Arabia. Materials and Methods: A two-section questionnaire was developed using online web-based application (Google forms) and sent to 400 dentists. The first section collected demographic information and the second section concerned about the treatment concept and materials for restoring ETT. Descriptive statistics were used to analyze the data, followed by Chi-square or Fisher's exact test to compare the responses to different questions among general dentists and specialists/consultants. Results: A total of 138 questionnaires were completed. Most of the participants reported a frequently or always use of extracoronal restoration in anteriors (55.1%), premolars (89.1%) and 88.4% for molars. Participant reported frequent placement of posts in anteriors (56.5%), premolars (84.1%) and 64.5% for molars. Nonmetallic post and cast post and core were the preferred option for anteriors and molars, while responses were equally divided between nonmetallic post and cast post and core for premolars. Composite resin was the preferred core material for all teeth. Conclusions: The use of endodontic posts, composite resin as a core and extracoronal restoration for restoring ETT is common among participants. Some of the concepts expressed by the participants are outdated and does not coincide with the evidence-based practice.

Additive Manufacturing in Dentistry: Current Technologies, Clinical Applications, and Limitations

Purpose of ReviewThis review aimed to illustrate the utility of additive manufacturing technologies for the fabrication of polymer, metal, and ceramic components within the confines of their current and potential clinical applications in dentistry.Recent FindingsThe literature reviewed on five additive manufacturing technologies, namely, vat-polymerization, material jetting, material extrusion, powder-based fusion, and binder jetting, have been investigated in relevance to their dental applications. These technologies have the following existing or potential clinical applications: diagnostic and definitive casts, custom trays, positioning guides for custom abutments, tooth preparation guides, interim dental restorations, all-ceramic crowns, metal crowns and copings, silicone indices, occlusal devices, complete dentures, wax patterns for intra- and extra-coronal restorations, surgical guides, removable partial dentures, and tooth- or implant-supported frameworks.SummaryVat-polymerization, material jetting, and powder-based fusion technologies have existing clinical applications utilizing mainly polymers and metals. Additive manufacturing technologies need further development to be used with ceramic materials for dental applications.

THE BIOMECHANICAL COMPARISONS OF DIFFERENT PERIODONTAL CONDITIONS UNDER THE DIFFERENT EXTRACORONAL PRECISION ATTACHMENT RESTORATIONS FOR THE MANDIBULAR KENNEDY I DENTITION DEFECT

Extracoronal precision attachment provides an available solution for complicated periodontal conditions in patients with dentistry defect. The mandibular Kennedy I dentition defect refers to the dentition defect at bilateral free-end molars. The bilateral nearby teeth are used as the abutment of extracoronal precision attachment to offer supporting forces. However, it is difficult to choose the quantities of abutments for patients with various periodontal conditions. The aim of this study is to suggest quantities of abutments based on stress distributions under various periodontal conditions for patients with mandibular Kennedy I dentition defect. Models were constructed from computed tomography, and they were assembled and analyzed in ANSYS. Seven models were used in our study based on different periodontal conditions and quantities of abutments (three models in healthy periodontal condition using single, double and triple abutment(s) restorations, two models with one absorbed abutment using double and triple abutments restorations and two models with two absorbed abutments using double and triple abutments restorations). The degree of absorbed abutments was 1/3. The mandible and other structures were considered as an orthotropic material and isotropic materials, respectively. Loads and boundary conditions corresponded to the realistic occlusion. Poor periodontal conditions enlarge the stress on abutments and surrounding structures. In addition, the increase in quantity of abutments causes the decrease and distribution of stress to differ. Different periodontal conditions require different quantities of abutments for recommendation in rehabilitation. The double abutments restoration is suitable for patients without absorbed abutment. The triple abutments restoration should be considered for patients with only one absorbed abutment. If more than two absorbed abutments exist, the extracoronal attachment denture restoration is not recommended for patients.

Extra Coronal Esthetic Restorations: Clinical Predictability in Pediatric Dentistry

A variety of esthetic restorative materials has been introduced in the past decades for restoring primary incisors. However, knowledge of the specific strengths weakness and properties of each material will enhance the clinician’s ability to make the relevant choice of selection for each individual personalized treatment plan. The objective of this review was to discuss the advancements in esthetic restorations for restoring primary incisors in a clinical situation. Individualized treatment planning and optimum professional judgement is essential for selecting the extra coronal restorations for primary dentition. Nevertheless, CAD/CAM crowns can be promising alternative options for full-coronal coverage. Moreover, long-term follow-ups and further clinical trials are required to support the evidence.

Comparison of reconstruction of cement space in resin copings fabricated with the use of a 3D printer in single- and three-unit restorations

Marginal and internal gaps are very important factors in fixed prosthetic restorations. The marginal fit is affected by the cementing process of the restoration. One of the techniques used to create the required space between the prepared tooth and the crown is to use a die spacer. The aim of the current study was to assess the accuracy of reconstruction of the cement space in the resin copings of extracoronal restorations fabricated with the use of the 3D printing technique and compare it in single- and three-unit restorations. After taking impressions from the left maxillary first premolar and first molar teeth of a jaw model, a total of 20 models were prepared with the use of a 3D printer for single-unit and three-unit groups (a total of 120 samples) and cemented on their relevant dies. The samples were sectioned buccolingually. The images of the internal gaps were prepared under a light microscope and evaluated. The values in different groups were compared in relation to marginal and internal fit and analyzed with ANOVA (mixed models). Statistical significance was set at P&lt;0.05. Comparison of the accuracy of reconstruction of the cement space in resin copings fabricated with the use of a 3D printer showed that in the single-unit premolar tooth with a presumptive cement space of 45 µm the cement space was 30.45±20.01 µm (P&gt;0.001) at the margin and 36.01±13.52 µm (P&gt;0.001) in the internal area; in the reconstruction of the three-unit molar tooth with a presumptive cement space of 25 µm, the cement space at the margin was 105.97±33.7 µm (P&gt;0.964), with 120.09±63.15 µm (P&gt;0.005) in the internal area. It was concluded from the results of the present study that the accuracy of reconstruction of the cement space in resin copings fabricated with the use of a 3D printer in samples with a larger presumptive cement space was higher than that in samples with a smaller presumptive cement space. The accuracy of the reconstruction of the cement space in resin copings fabricated using a 3D printer in single-unit restorations was higher than that in three-unit restorations.

Extra-coronal restorations: concepts and clinical application, second edition

Extra-coronal restorations: concepts and clinical application, second edition