Porcelain-fused-to-metal Research Articles

The Effects of Different Restoration Materials on the Trueness of Intraoral Scanners

Aim: This study aimed to assess how different restoration materials affect the trueness of intraoral scanners. Materials and Methods: Artificial teeth on a typodont model were prepared for crowns and fixed partial dentures (FPDs) using full metal, monolithic zirconia, and porcelain-fused-to-metal (PFM) materials. Each group underwent 10 scans with a Trios intraoral scanner, generating 60 STL files. A reference scanner created a master model using scanning spray to reduce reflection errors. The STL files were aligned with reverse engineering software for comparison and were analyzed in micrometers (μm) using Root Mean Square (RMS) and Mean Distance measurements. The Levene test and two-way ANOVA with Post Hoc analysis were used for statistical evaluation. Results: The RMS deviations for the FPDs were 77.9 ± 15.2 μm (full metal), 84.6 ± 6.9 μm (monolithic zirconia), and 130 ± 19.7 μm (PFM). For the crowns, the RMS values were 76.9 ± 6.5 μm (metal), 71 ± 8.2 μm (monolithic zirconia), and 153 ± 22.4 μm (PFM). The mean distance deviations for the FPDs were 11.4 ± 4.8 μm (metal), 11.2 ± 3.4 μm (monolithic zirconia), and 18.3 ± 2.6 μm (PFM). For the crowns, the mean distances were 8.6 ± 3.4 μm (metal), 10.2 ± 3 μm (monolithic zirconia), and 24.7 ± 3.3 μm (PFM). Significant differences were noted in the PFM groups. Conclusion: Restoration materials notably affected intraoral scanner trueness, especially PFM restorations. The restoration length did not significantly affect the accuracy.

Prevalence of Dentine Hypersensitivity in Vital Abutment Teeth being prepared for Fixed Partial Dentures or Crowns

Objective: To determine the prevalence of dentine hypersensitivity during the preparation of vital abutment teeth for Fixed Partial Dentures or Crowns and its association with patient’s gender, age, and location of tooth. Study Design & Setting: This is a descriptive cross-sectional study of patients with 150 abutments of either crown or fixed partial dentures, carried out in the department of Prosthodontics at Armed Forces Institute of Dentistry (AFID) Rawalpindi from June to December 2021. Methodology: The Dentine Hypersensitivity was recorded on a VAS (Visual Analogue Scale) of 0-10 after the patient reported pain during exposure to thermal stimulus i.e. cold water from a 5cc syringe at 1cm distance during or just after the tooth preparation. Results: In this study, the prevalence of Dentine Hypersensitivity was 13.3% with a mean dentine hypersensitivity score (VAS) for cold water test (Mean ± SD) of 0.61±1.756. Independent samples t-tests were used to determine the difference in hypersensitivity between genders, two age groups, and type of tooth (anterior/ posterior). It showed significant results with p-values of 0.002, 0.002, and 0.003 respectively. Conclusion: Within the limitations of this study, it was highlighted that the preparation of vital teeth for conventional porcelain fused to metal (PFM) crown or fixed dental prosthesis results in dentine hypersensitivity in a considerable number of cases, with a higher incidence in women, younger patients, and vital anterior abutments.

Survival, technical and biological outcome of fixed tooth- and implant-supported restorations: A retrospective analysis of a patient cohort treated in an undergraduate dental education program

ObjectivesThere is a paucity of data on the outcome of fixed tooth- and implant-supported porcelain-fused-to-metal (PFM) and ceramic-based (CB) restorations fabricated during undergraduate dental education. Therefore, this retrospective study examined the outcome of fixed restorations placed in patients participating in an undergraduate program. MethodsPatient records were searched for data on fixed PFM and CB restorations. For these restorations, the functional period in situ and technical and biological complications, namely restoration fracture, decementation, screw loosening, secondary caries, and loss of vitality, were recorded. Periodontal parameters were also documented. Kaplan-Meier survival and complication estimates after 1 and 5 years were calculated for restoration types, materials, designs (veneered/non-veneered), cementation/retention modes and localizations with group sizes ≥ 15. Regression models were used to analyze the influence of demographic data and abovementioned restoration characteristics on restoration survival, technical and biological outcome. Results1196 restorations with a mean observation time of 5 years were included in the analysis. The different restoration types exhibited survival rates of > 90.8% after 5 years, accompanied by a favorable biological outcome. However, monolithic resin-matrix or feldspathic ceramic restorations were found to have a higher fracture rate than lithium disilicate or zirconium dioxide ceramic restorations resulting in lower survival rates for these restorations. Additionally, resin-matrix ceramic restorations showed a higher decementation rate than lithium disilicate restorations. ConclusionsFixed tooth- and implant-supported CB restorations fabricated from lithium disilicate and zirconium dioxide ceramics demonstrated better survival and lower complication rates than restorations fabricated from resin-matrix or feldspathic ceramics in an undergraduate dental education program. Clinical significanceDue to the more favorable outcome of CB restorations fabricated from lithium disilicate or zirconium dioxide ceramics, undergraduate dental education should focus on the application of these ceramics to increase restoration survival by reducing technical complications.

Effect of Prosthetic Material and Support Type on Stress Distribution of Fixed Partial Dentures: A Finite Element Study

Choosing an appropriate prosthetic material for the superstructure of an implant-supported or tooth-implant supported fixed partial denture (FPD) is crucial for the success of the prostheses. The objective of this study was to examine the effect of prosthetic material type and tooth-to-implant support on stress distribution of FPDs using three-dimensional finite element analysis (3D FEA). Two FEA models were generated, distinguished by their support configurations: Model I representing an FPD supported by implants, and Model II depicting an FPD supported by both a tooth and an implant. Two different restorative materials, porcelain-fused-to-metal (PFM) and monolithic zirconia, were evaluated for stress distribution under axial and oblique loads of 300 N applied to the pontic. Under both axial and oblique loading conditions, the maximum von Mises stress values were observed to be higher in the implant-abutment complex of both zirconia implant-supported and tooth-implant-supported FPDs compared to PFM FPDs. In the case of axial loading, comparable stress values were found in the cortical bone for PFM (12.65 MPa) and zirconia implant-supported FPDs (12.71 MPa). The zirconia tooth-implant-supported FPD exhibited the highest stress values in the implant-abutment system.

The Effects of using PEEK Coping and Different Restorative Materials on the Stress Distribution in Tooth and Implant- supported Prostheses under Static Loading: 3D FEA.

This study was designed to evaluate the influence of utilizing Polyetheretherketone (PEEK) coping and three different dental restorative materials in the success of tooth and implant-supported fixed partial dentures (TISFPD) in the maxillary posterior region, under static loading by 3-Dimensional Finite Element Analysis (3D FEA). Six 3D FEA models were designed assuming the extraction of maxillary first and second molars. Bone, implant, abutment, PEEK coping, second premolar, periodontal ligament (PDL) and six 3-unit TISFPD with different restorative materials [Porcelain-Fused-to-Metal (PFM), PEEK-Composite (PC), Monolithic Zirconia (MZ)] were modeled. Then, PEEK copings were modeled to be cemented onto the implants as a double-crown system for the first three groups (PFMPEEK, PCPEEK and MZPEEK) whereas, the next three groups (PFM, PC, MZ) excluded a PEEK coping in their designs. The prostheses were loaded twice, vertically and obliquely. From the determined points, 250 N for vertical loading (0o to the long axis) and 200 N for the oblique loading (30o to the long axis) were applied. Von Mises tension, maximum and minimum principal tension value criterias were analyzed. Regardless of the material used for suprastructure, the maximum average stress was reduced by using PEEK coping. Considering the maximum stress distribution, PC appeared to have the highest stresses on the cortical bone, implant and screw. Additionally, the von Mises stresses formed in the PDL for each model were lower when PEEK coping was included in the design of the TISFPD, reducing the risk of intrusion. The stress distribution was positively affected by the PEEK coping in TISFPD design, reducing bone resorption and failure. This elastic material used generated lower stresses in the bone and implant, while no significant effect was found on stresses around natural teeth.

A Comprehensive Review of the Surface and Chromatic Properties of Monolithic Zirconia: Evaluating the Impact of Polishing and Finishing Methods on Aesthetics and Performance.

Monolithic zirconia is widely used in dentistry due to its outstanding mechanical properties, biocompatibility, and aesthetic qualities. This review examines how different polishing and finishing methods impact the performance and appearance of monolithic zirconia restorations. Derived from zirconium, zirconia is a robust ceramic that exists in monoclinic, tetragonal, and cubic forms, with properties that prevent crack propagation. Monolithic zirconia, preferred over porcelain-fused-to-metal (PFM) crowns, offers better aesthetics and avoids chipping. Various surface treatments, such as polishing and glazing, enhance zirconia's smoothness and wear characteristics. Polished zirconia is less abrasive to enamel than glazed zirconia, making it more suitable for opposing teeth. Research indicates that polished zirconia has a smoother surface and higher fracture resistance compared to other dental ceramics. Surface roughness, which is influenced by the treatment method, is crucial in minimizing wear on opposing teeth. Polished monolithic zirconia also shows high flexural strength, chipping resistance, and translucency. While both polishing and glazing reduce brightness, polishing better preserves translucency. The literature identifies polishing as the best post-processing method for enhancing zirconia's surface quality and mechanical properties without compromising its load-bearing capacity. In conclusion, polishing and finishing significantly improve the aesthetic and clinical performance of monolithic zirconia, confirming its effectiveness for durable and visually appealing dental restorations.

Management of dislodged crown using split cast metal post and core: A case report

Across diverse cultures, the practice of restoring lost tooth structure has endured through generations. It is widely understood that merely undergoing quality endodontic therapy is not sufficient to fully restore a severely weakened tooth with pulpal disease. Equally crucial is ensuring post-endodontic restoration followed by quality prosthetic rehabilitation. In instances where a tooth is extensively damaged, utilizing a post becomes the preferred course of action post endodontic treatment to preserve the core. The gold standard for the treatment of a severely compromised tooth is recognized as a cast post and core. In this case study, a previously treated maxillary first molar, which had a dislodged fiber post and core along with a porcelain-fused-to-metal (PFM) crown, underwent retreatment with a split cast metal post and core followed by a PFM crown.

Survival Rate of Self-Adhesive Resin Cement on Various Crown Materials: A Scoping Review

Abstract Aim: The use of crowns made of all-ceramic, metal-ceramic, or porcelain fused to metal (PFM) with a self-adhesive resin cement as an indirect restorative process is a method of indirect restorative. The cement is anticipated to improve survival rates due to its many benefits. Thus, this research aimed to ascertain how long self-adhesive resin cement will last when applied to different types of crown materials. Materials and Methods: The study used a scoping review methodology that followed a Population, Concept, and Context framework. The articles included were published from January 1, 2013, to May 24, 2023, full-text, full-access, written in English, original article study design (clinical studies, observational studies, follow-up case reports, and comparative studies), and in vivo method. Boolean operators were applied to search across the databases Science Direct, PubMed, and EBSCOhost with the corresponding keywords “((survival rate) OR (success rate) AND (adhesive resin cement) AND (crown)).” Since Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) was implemented as the study design, it did not include randomization or statistical analysis. However, we added bias-risk information. Results: There were 104 studies in total. After the duplication checking and abstract screening processes, 23 articles were provided. A full-text assessment was done, and seven articles were extracted. Additionally, information about the author, publication year, study design, research methodology, self-adhesive resin cement brand, crown material, research duration, and outcomes was gathered. Conclusions: The results concluded that the self-adhesive resin cement survival rate on various crown materials, both all-ceramic and PFM, within 6 years is excellent. Due to the minimal number of articles that met the inclusion criteria, additional research is required.

Ni–Cr dental alloys - porcelain firing impact on corrosion properties and surface characteristics

Biocompatibility is a critical aspect of the use of materials in the human body. The use of base metal alloys in dentistry is primarily regulated by health and safety standards set by regulatory authorities in various countries. The porcelain-fused-to-metal (PFM) process applied to Ni-Cr dental alloys can alter their properties, particularly in terms of corrosion and surface characteristics. This study aimed to assess the effect of the heat processing used for dental porcelain firing on these properties. The two casted alloys: Ceramic N and Ivoclar Vivadent 4all, used in the study were characterized by analyzing the microstructure by scanning electron microscopy (SEM), composition with energy dispersive x-ray spectroscopy (EDS), hardness, surface profile and electrochemical corrosion resistance (Ecorr, jcorr, polarization curve, Ebr and electrochemical impedance spectroscopy (EIS) results), as well as ions release before and after the simulated porcelain firing. Based on the conducted research the following conclusions can be drawn: Analyzes of the material characteristics before and after the simulation showed that the discussed process, although it does not cause the formation of chemical impurities on the surface of the alloys, results in changes in the chemical composition and structure of surface oxides, increases roughness and reduces hardness. The results of the corrosion examinations showed a deterioration in anti-corrosion properties after the simulation. The statistically significant decrease in corrosion resistance may result from the increased heterogeneity of the surface oxide layers and partial changes in their composition.

Major Failures and Key Risks Linked to Dental Fixed Prostheses: An in vivo Clinical Study

This clinical investigation aimed to identify factors leading to fixed partial denture failures and their implications, crucial for enhancing clinical outcomes. Conducted in Tripoli, Libya, with 75 patients contributing 235 units, the study utilized John F. Johnston's and John J. Manappallil’s classifications to categorize failure causes. Mechanical issues, predominantly in female patients, were identified as the primary cause of dental bridge failure, particularly in porcelain fused to metal (PFM) bridges with a "Fixed-Fixed" design, mostly in the upper jaw. The study underscores the importance of a multifactorial approach in preventing and managing fixed partial denture failures, emphasizing meticulous prosthesis design, manufacturing, and placement, alongside patient selection, diagnosis, treatment planning, and oral hygiene education.

REVIVING YOUR PORCELAIN SMILE: A GUIDE TO INTRAORAL REPAIR OF FIXED PORCELAIN PARTIAL DENTURES: A LITERATURE REVIEW

Background: Porcelain or ceramic-based materials are popular in dentistry due to their aesthetic appeal and biocompatibility. However, chipping or fractures in fixed partial dentures can disrupt aesthetics and functionality. Intraoral repair offers a cost-effective and time-saving solution. Objective: This study aims to guide practitioners in managing chipping crowns, saving time and costs while ensuring satisfactory outcomes for patients. Method: The review included articles on intraoral repair of porcelain fixed partial dentures, published in peer-reviewed journals, available in English, and including clinical trials, case reports, and reviews. Exclusions were non-dental studies, non-English articles, and studies focusing on temporary restorations. Data on the etiology of chipping, necessary tools, and management steps were collected. Result: Porcelain Fused to Metal (PFM) denture repairs are difficult due to color matching and procedural complexity. Repairing Lithium Disilicate dentures is moderately challenging, requiring meticulous surface preparation. The most complex repairs are for Zirconia-based prostheses, needing specialized equipment and advanced techniques for a durable bond. Conclusion: Intraoral repair techniques provide a quick, precise, and comfortable solution for patients. Understanding the stages of intraoral repair allows clinicians to achieve optimal functional and aesthetic results. Clinicians should evaluate their expertise and resources to select the appropriate technique, with composite resin repairs being the easiest and Zirconia-based repairs the most challenging. This method helps deliver quick and satisfying results, enhancing the longevity and aesthetics of fixed porcelain dentures.

Validation of the pink esthetic score/white esthetic score at single tooth-supported prostheses in the esthetic zone: A randomized clinical trial.

To validate the reproducibility and inter/intra-observer variability of the Pink Esthetic Score/White Esthetic Score (PES/WES) of single tooth-supported prostheses in the maxillary esthetic zone (13-23). Forty-five patients were randomly assigned to one of the three treatment options (15 patients per group) receiving each one a different crown type: Porcelain fused to metal (PFM), monolithic zirconia, and lithium disilicate. Eight observers from each of four different specialties (Prosthodontists, Orthodontists, Periodontists, and Oral Surgeons) were recruited and assessed twice and four weeks apart (i.e., T1 and T2) 45 photographs of the single tooth-supported prosthesis using PES/WES and compared them with contralateral teeth. According to the ANOVA and post hoc tests, the zirconia crown type obtained the highest mean score by all observers, with a mean value of 16.70 ± 2.94. The prosthodontists and oral surgeons assigned the lowest mean score to PFM crowns, 13.03 ± 3.47 and 13.80 ± 3.17, respectively. Notably, the prosthodontists awarded the highest scores, specifically 17.50 ± 2.81 for the zirconia crowns. Intraobserver agreement was calculated utilizing the paired t-test. Pairwise comparisons between observers of different specialties revealed significant intraobserver agreement. Interclass correlation coefficient (ICC) scores were statistically significant among four specialties. No difference was detected concerning the interobserver agreement. The PES/WES index remains consistent across various observers from different specializations, yielding uniform results in the overall esthetic evaluation. Consequently, in light of the presented preliminary positive results, its use might also be considered for the esthetic assessment of single-tooth-supported prostheses. The PES/WES index may be employed clinically to evaluate single tooth-supported prostheses as it emerged as a reproducible esthetic scoring system.

Comparison of the Effect of Implant Abutment Surface Modifications on the Retention of Implant-Supported Restorations.

To evaluate and compare the difference in retention between implant-supported restorations with and without surface modification of the implant abutments. A total of 30 patients with singletooth implants were restored with cement-retained (Multilink N, Ivoclar) restorations using titanium base abutments (Variobase, Straumann) and randomly assigned surface modifications. Group 1 used nonmodified abutments, group 2 used sandblasted abutments, and group 3 used sandblasted abutments followed by an application of metal primer. All patients were recalled for a baseline examination 6 months after crown placement. The pull-out strength and intergroup distribution of mean pull-out strength were assessed. To assess differences between the three groups, intergroup statistical comparison of continuous variables was done using one-way ANOVA with Tukey correction for multiple group comparisons. The results of the intergroup mean pull-out strength distribution revealed that the distribution of mean ± SD pull-out strength in group 1, group 2, and group 3 were 220.79 ± 94.23, 488.64 ± 84.12, and 705.46 ± 112.75 Ncm, respectively. Sandblasting followed by the application of metal primer produced the highest retention of porcelain-fused-to-metal (PFM) crowns to titanium base abutments, followed by sandblasting alone, with the least retention being observed with no surface treatment.

Clinical evaluation of posterior zirconia-based and porcelain-fused-to-metal crowns with a vertical preparation technique: an up to 5-year retrospective cohort study

ObjectiveTo evaluate the clinical conditions of single-unit posterior restorations on teeth prepared without finishing line, after 5.6 years of clinical service. Materials and methods50 crowns (25 zirconia-based (Zr) and 25 porcelain-fused-to-metal (PFM)) were selected from 34 patients. The restorations were evaluated according to the California Dental Association (CDA) Quality Criteria, and periodontal variables were studied in the abutment teeth compared with the unrestored contralateral teeth. Variables were examined using Mann-Whitney and Pearson´s Chi-Square tests (α = 0.05). The success of the prosthesis was calculated using Kaplan-Meier test. ResultsCDA Quality Criteria was considered satisfactory-excellent in all restorations except for one of them, due to chipping on a PFM crown. At, 66 months, the success rates for PFM and Zr crowns were 85.7 % and 100 %, respectively. The plaque index (PI) showed that the restored abutment teeth accumulated significantly less plaque than the control teeth, but the gingival index (GI) was statistically higher in the abutment teeth. In 80 % of cases the probing depth (PB) was ≤3 mm. In addition, in 21 % of the cases, gingival recession was less than 2 mm. The restoration material had a statistically significant effect on GI and PB, with Zr crowns showing less inflammation and less deep pockets than PFM restorations. On the contrary, greater gingival recession was found at the margins of the Zr crowns when compared to the PFM. No statistical differences were found between the two materials in the GI. ConclusionsCemented crowns on vertical preparations show good clinical behavior after 5 years. The periodontal parameters (PI, GI, PD) of the Zr restorations are significantly better than those of PFM, with the exception of gingival recession. Clinical relevanceThe use of restorations on vertically prepared teeth is a suitable alternative to classical horizontal preparations.

Adhesive Resin Cementation of Posterior Hybrid-type Retainer Porcelain Fused to Metal Fixed Dental Prostheses

Porcelain fused to metal (PFM) of fixed dental prostheses (FDP) remains the gold standard for rehabilitating partial edentulous. However, conventional PFM FDP requires lengthy procedures to achieve optimum retention, resistance, and esthetics, such as the geometry and depth of preparation. Adhesive technology could minimize the complexity of cementation to achieve retention and resistance by minimizing the preparation area, thus ruling out the geometry of preparation consideration. The optimal geometry of preparation is achieved by the preparation of a tooth structure with significant depth and geometry. Thus, abandoned preparation geometry increases the use of minimally invasive prosthodontics. Minimally invasive prosthodontics could minimize the possibility of future endodontic treatment. One option for treating partially edentulous patients with a minimally invasive approach is the hybrid PFM FDP, consisting of an inlay-bonded retainer with the vital tooth in one of the abutments and a conventional retainer with the non-vital tooth in the other. As a result, this report showed the reasoning and technology for cementation of hybrid-type retainer PFM FDP using adhesive technology in the posterior area. Findings uncovered that using adhesive technology, the cementation FRC FDP of hybrid-type retainer PFM FDP could minimize the preparation and cementation procedure without compromising retention and resistance. Therefore, future usage of hybrid-type retainer PFM FDP should be encouraged from a minimally invasive point of view

Analysis of subgingival microbiota and IL-1β, TNF-α and CX3CL1 levels in gingival crevicular fluid of fixed dental prostheses.

Prosthetic biomaterials can affect the composition of the subgingival microbiota and consequently the production of proinflammatory cytokines, causing damage to the periodontium. A total of 40 patients were divided into two groups: 20 with monolithic zirconia (MZ) prostheses and 20 with porcelain fused to metal (PFM) with nickel-chromium (Ni-Cr) alloy prostheses. Subgingival plaque and gingival crevicular fluid samples were taken. The Checkerboard technique for DNA-DNA hybridization and the enzyme-linked immunosorbent assay technique were performed. Teeth with MZ presented a lower percentage of bleeding on probing and tooth mobility compared to teeth with PFM with Ni-Cr alloy. Prosthodontic teeth harbored higher total levels of the 18 bacterial species than non-prosthodontic teeth. There was a higher prevalence of S. gordonii and V. parvula species in PFM with Ni-Cr alloy compared to MZ. There was an increase in IL-1β, TNF-α and CX3CL1 levels in PFM with Ni-Cr alloy compared to MZ. MZ is a candidate biomaterial with fewer negative effects on the periodontium, allowing for longer prostheses longevity in the mouth.

The Role of Digital Facebow for CAD/CAM Implant-Supported Crowns Workflow.

Recent advancements in digital technologies have transformed clinical workflows in dentistry, ensuring precise restorations. Custom-made crowns and fixed partial dentures (FPDs) now rely on virtual articulation. The digital facebow provides individualized data for CAD settings, streamlining the fabrication via digital workflow. For the purpose of demonstrating the differences observed during fabrication, we present a case report involving a 68-year-old patient seeking a replacement for missing teeth 24, 25, 26, and 27. The treatment plan involved the fabrication of an implant-supported FPD using monolithic zirconia (ZrO2). However, technical hurdles emerged during the planning phase, primarily due to spatial limitations posing a risk of mechanical failure over time. Consequently, we pivoted approach towards a porcelain fused to metal (PFM) FPD. For the PFM FPD, individual values from the digital facebow adjusted both virtual and conventional articulators. For comparison, two ZrO2 FPDs were milled-individual settings and average settings. All restorations underwent assessment for occlusion in maximal intercuspal position and eccentric mandible movements. In conclusion, the case report showed that individualized PFM FPD required minimal adjustments compared to milled ZrO2 restorations, whether using individual or average values. Utilizing individual values from the digital facebow reduced operator working time and minimized the intraoral adjustments.

Guided Bone Regeneration to Support Lack of Mandibular Buccal Plate

Background: Insufficient bone condition can pose a significant challenge in dental implant procedures. The success of implant therapy relies on having sufficient bone thickness at the implant site. Factors such as bone atrophy, periodontal disease, trauma, and intermaxillary relationships (vertical, horizontal, and sagittal) can lead to insufficient bone volume for placing implants. To address this issue, bone augmentation techniques are commonly used to restore function and improve aesthetics in areas with inadequate bone. Various techniques and materials are available for bone augmentation, including Guided Bone Regeneration (GBR), which is one of the known methods with varying success rates. Objective: provide information about the management of bone augmentation in dental implants using the GBR technique. Case report: involves a 21-year-old male patient who sought treatment at a clinic to resolve functional issues and prevent dental shifting following a tooth extraction. The patient desired permanent dentures for the left mandibular area. After undergoing several examinations, it was determined that dental implants on tooth 46, with a diameter of 4.1 mm and length of 10 mm, accompanied by a cemented-screw type porcelain-fused-to-metal (PFM) crown, would be appropriate. In this particular case, the GBR technique with allograft bone grafts was employed for bone augmentation. After approximately one year of observation, evidence of new bone formation was observed, indicating the success of the dental implant treatment. Conclusion: there are several effective techniques for correcting inadequate bone conditions before placing dental implants.

Comparative Evaluation of the Effect of Implant Crown Materials on Implant Components and Bone Stress Distribution: A 3D Finite Element Analysis.

Choosing implant crown materials for restoration remains challenging in clinical practice. This study assesses the impact of all-ceramic restoration instead of porcelain-fused-to-metal (PFM) restoration on the stress distribution within implant components and the surrounding bone. Four 3D models of a mandibular second premolar were meticulously prepared. The study groups comprised zirconia, lithium disilicate, and zirconia lithium silicate monolithic ceramic crowns cemented onto a zirconia hybrid abutment. A PFM crown cemented onto a cementable abutment was chosen as the control group. A total vertical load of 583 N was applied to the occlusal contact areas. Stress distribution within the crown and implant components was analyzed using von Mises stress analysis. Principal stress analyses were employed to assess stress distribution in the peripheral bone. The PFM model exhibited the highest von Mises stress values for both the implant (428.7 MPa) and crown (79.7 MPa) compared to the other models. The all-ceramic models displayed the highest maximum von Mises stress within the abutment, approximately 335 MPa, compared to the PFM model. von Mises stresses of the abutment and implant in the all-ceramic models were 69% higher and 20% lower, respectively, than those in the PFM model. Screw stresses were relatively consistent across all groups. Principal stresses in spongy bone and minimum principal stress in cortical bone were consistent across all models. All-ceramic restoration with a hybrid abutment, as opposed to traditional PFM restoration with a cementable abutment, does not adversely affect the implant and abutment screw and reduces crown stresses. Stresses within hybrid abutments were notably higher than those within cementable abutments. Spongy bone stresses remained unaffected by the type of crown or abutment.

Distribution and preferences of conventional fixed dental prostheses among patients at the National Referral Hospital, Bhutan

Introduction: Structural defects in teeth significantly impact oral health, leading to broader implications for an individual’s overall well-being. Porcelain-fused-to-metal (PFM) crowns and bridges are the preferred forms of fixed dental prostheses (FDP) for restoring lost form, function, and aesthetics of the missing or damaged tooth/teeth. This study aimed to investigate the distribution pattern and proportions of FDP across genders, age groups, types of teeth, and jaw locations. Methods: This was a retrospective analysis of records of dental prostheses availed at the National Referral Hospital from July 2016 to June 2021. Specific data on FDP were extracted and utilized for the analysis. Results: The median age of patients was 33 (23 - 41) years for females and 37 (26 - 50) years for males. Female patients accounted for the majority of FDP recipients, consisting of 56.7% of the total cases. Posterior crowns (80.7%) and, anterior bridges (48.7%) are the most prevalent FDP types. In the upper jaw, a significant proportion of FDP consisted of posterior crowns (70.5%) and, anterior bridges (55.9%). In contrast, the lower jaw predominantly received more crowns (96.0%) and bridges (49.3%) in the posterior region. Conclusions: FDP are prevalent among female patients with a lower median age. Anterior bridges restoring aesthetics are more prevalent in the upper jaw, whereas the bridges and crowns for posterior teeth are more in the lower jaw. Dental practitioners can tailor treatment approaches to meet patient expectations, whether to focus on aesthetics or functionality.