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Polymers Oct 2023As cementation represents the last stage of the work involved in making various indirect restorations (metal ceramic crowns and bridges, full ceramic crowns and bridges,... (Review)
Review
As cementation represents the last stage of the work involved in making various indirect restorations (metal ceramic crowns and bridges, full ceramic crowns and bridges, inlays, onlays, and fiber posts), its quality significantly contributes to the clinical success of the therapy performed. In the last two decades, the demand for ceramic indirect restorations in everyday dental practice has considerably increased primarily due to the growing significance of esthetics among patients, but also as a result of hypersensitivity reactions to dental alloys in some individuals. In this context, it is essential to ensure a permanent and reliable adhesive bond between the indirect restoration and the tooth structure, as this is the key to the success of aesthetic restorations. Resin-based luting materials benefit from excellent optical (aesthetic) and mechanical properties, as well as from providing a strong and durable adhesive bond between the restoration and the tooth. For this reason, resin cements are a reliable choice of material for cementing polycrystalline ceramic restorations. The current dental material market offers a wide range of resin cement with diverse and continually advancing properties. In response, we wish to note that the interest in the properties of resin-based cements among clinicians has existed for many years. Yet, despite extensive research on the subject and the resulting continued improvements in the quality of these materials, there is still no ideal resin-based cement on the market. The manuscript authors were guided by this fact when writing the article content, as the aim was to provide a concise overview of the composition, properties, and current trends, as well as some future guidelines for research in this field that would be beneficial for dental practitioners as well as the scientific community. It is extremely important to provide reliable and succinct information and guidelines for resin luting materials for dental dental practitioners.
PubMed: 37896400
DOI: 10.3390/polym15204156 -
Materials (Basel, Switzerland) Oct 2023The conformation of the recipient site for an inlay graft presents an increased contact with the parent bone compared to an onlay graft. This might favor bone growth...
BACKGROUND
The conformation of the recipient site for an inlay graft presents an increased contact with the parent bone compared to an onlay graft. This might favor bone growth within the inlay compared to onlay grafts. Hence, the objective of this study was to compare the bone incorporation and remodeling processes of xenogeneic en bloc grafts placed using two bone grafting techniques, i.e., onlay vs. inlay.
METHODS
In this prospective, randomized, split-mouth study (test and control sides in the same animal), two bone grafting techniques were comparatively evaluated. The lateral aspect of the rabbit mandible was used as the recipient site, bilaterally. On one side of the mandible, the cortical bone was perforated with drills to allow a better bone formation from the bone wound and the marrow spaces. A xenogeneic bone block was fixed in the center of the prepared region, representing the onlay site. On the other side of the mandible, a 7 mm wide and 3 mm deep circumferential defect was prepared using trephines and drills. A xenogeneic bone block was fixed in the center of the defect, representing the inlay site. Two healing periods were applied in the study: 2 and 10 weeks, each represented by 10 rabbits ( = 10 for each period).
RESULTS
After 2 weeks of healing, the mean percentage of new bone was 10.4% and 23.3% at the onlay and inlay grafts, respectively ( = 0.022). After 10 weeks of healing, new bone increased to 13.2% at the onlay sites and 25.4% at the inlay sites ( = 0.080). In the 10-week period, the inlay grafts presented a homogeneous growth of new bone in all regions, while in the onlay grafts, low percentages of new bone were observed in the external regions.
CONCLUSION
The percentage of new bone increased faster and was higher in the inlay grafts than in the onlay grafts. This outcome might be related to the self-contained conformation of the recipient site in the inlay group, which offered more sources for new bone formation compared to the one-wall conformation of the recipient sites in the onlay group. The osteoconductive properties of the biomaterial allowed the newly formed bone to reach the most peripheral regions in both groups. The osteoconductive properties of the biomaterial, together with the protection offered by the collagen membrane, allowed marginal closure of the defects by newly formed bone in the inlay group.
PubMed: 37895725
DOI: 10.3390/ma16206742 -
Clinical Oral Investigations Dec 2023Evaluation of cumulative survival and complication rate of monolithic lithium disilicate inlays and partial crowns performed by supervised undergraduate students up to...
OBJECTIVES
Evaluation of cumulative survival and complication rate of monolithic lithium disilicate inlays and partial crowns performed by supervised undergraduate students up to 8.3 years of clinical service.
MATERIALS AND METHODS
In this retrospective clinical study 143 lithium disilicate posterior restorations (IPS e.max Press) were examined according to the FDI criteria. A standardised questionnaire was used to determine patient satisfaction. The aesthetic outcome was evaluated by dentists and dental technicians using intraoral photographs. Data were descriptively analysed. Cumulative survival and success rates were calculated using Kaplan-Meier estimation.
RESULTS
The cumulative survival rate of lithium disilicate restorations was 97.5% after a mean service time of 5.9 years and 95.0% after 8.3 years. The cumulative success rate decreased from 94.4% after 5.9 years to 30.7% after 8.3 years. Repairs were required for 7 restorations (4.9%), and 5 (3.5%) were classified as failures. The results of the questionnaire indicate a high level of patient satisfaction. The subjective aesthetics were assessed more critically by dental technicians compared to dentists.
CONCLUSION
Lithium disilicate posterior restorations survived successfully up to 8.3 years when carried out by undergraduate students.
CLINICAL RELEVANCE
Pressed lithium disilicate glass ceramic inlays and partial crowns are reliable treatment options in posterior teeth.
Topics: Humans; Crowns; Retrospective Studies; Dental Restoration Failure; Esthetics, Dental; Dental Porcelain; Ceramics
PubMed: 37870592
DOI: 10.1007/s00784-023-05328-0 -
International Journal of Dentistry 2023Evaluating the level of dental students' competence is crucial for validating their preparedness for graduation. Confidence has a significant role in achieving...
Dental Students' Perception and Self-Perceived Confidence Level in Key Dental Procedures for General Practice and the Impact of Competency Implementation on Their Confidence Level, Part I (Prosthodontics and Conservative Dentistry).
BACKGROUND
Evaluating the level of dental students' competence is crucial for validating their preparedness for graduation. Confidence has a significant role in achieving competence. There are limited studies that assess the level of self-perceived confidence among final-year dental students regarding their ability to conduct key dental procedures. This study aims to assess the self-perceived confidence level of final-year dental students in performing essential dental procedures across various dental disciplines and to assess the effect of implementing competencies in the curriculum on the self-perceived confidence level of students by comparing two cohorts of final-year students in two different years 2016 (Traditional Cohort) and 2019 (Competencies Cohort).
MATERIALS AND METHODS
An questionnaire was answered by two cohorts of final-year dental students: one group in 2016 before the implementation of the competency-based assessment system (group 1, = 153), and the other in 2019 after the implementation of this system (group 2, = 199), the same questionnaire was used for both cohorts. The results from the two groups were compared regarding the degree of self-perceived confidence in conducting key dental procedures. The data were analysed using SPSS statistics and Levene's Test for Equality of Variances and -test for Equality of Means calculated.
RESULTS
Group 1 showed a significantly higher means of self-perceived confidence levels than group 2 in the ability to conduct seven out of the 20 prosthodontics procedures studied: providing patients with Cobalt-Chromium (Co-Cr) removable partial dentures (RPD) (3.77 vs. 3.56), providing the patient with Acrylic RPD (3.70 vs. 3.23), treatment planning for partially edentulous patients (3.83 vs. 3.34), giving OHIs for denture patients (4.17 vs. 3.95), dealing with CD postinsertion complaints (3.97 vs. 3.76), giving postinsertion instructions for removable prostheses cases (4.12 vs. 3.82), and providing patients with immediate dentures (2.67 vs. 2.32). The same applies to 6 out of 16 conservative dentistry procedures: placing anterior composite (4.41 vs. 4.12), placing posterior composite (4.43 vs. 3.88), placing posterior amalgam (4.29 vs. 4.02), placing matrix band for Class II restorations (4.24 vs. 3.71), placing a prefabricated post (3.34 vs. 2.88), and placing fiber post (3.45 vs. 3.34). On the other hand, group 2 shows higher means of self-perceived confidence than group 1 in only two conservative dentistry procedures: onlay restorations (2.18 vs. 2.76) and inlay restorations (2.22 vs. 2.75). No significant differences in means of self-perceived confidence were found between the two groups in the remaining 21 procedures studied.
CONCLUSIONS
This study has shown that final-year dental students have high self-perceived confidence levels in doing simple dental procedures yet less confidence in more complex ones. Although, students' self-perceived confidence decreases after the introduction of a competency-based assessment system. Competency implementation and execution criteria may differ between schools which may have an impact on final outcomes. Hence, there is a need for regular evaluation of competencies being assessed to maintain a curriculum that is up to date.
PubMed: 37868108
DOI: 10.1155/2023/2015331 -
Dental Materials : Official Publication... Dec 2023To evaluate retrospectively the longevity of lithium disilicate ceramic (LidiSi) vs. laboratory-processed resin-based composite (RBC) inlay/onlay/overlay restorations...
OBJECTIVE
To evaluate retrospectively the longevity of lithium disilicate ceramic (LidiSi) vs. laboratory-processed resin-based composite (RBC) inlay/onlay/overlay restorations and risk factors associated with restoration deficiencies and failures.
METHODS
Patients (n = 91) receiving LidiSi (73.1%) and RBC (36.9%) inlays/onlays/overlays between 2007 and 2017 were selected. The restorations were evaluated using the modified U.S. Public Health Service criteria. The survival of the restorations was analyzed using the Kaplan-Meier method and log rank test. Factors affecting the occurrence of deficiencies were examined by logistic regression analysis. This was performed with the use of the Generalized Estimating Equation model including Repeated measurements (GEER), with the consideration that the same patient had several teeth in the sample. Risk estimation was conducted for each evaluated criterion (p < 0.05).
RESULTS
The survival of LidiSi and RBC restorations were 96.8% and 84.9%, respectively after a mean observation period of 7.8 ± 3.3 years. The annual failure rate was 0.2% for LidiSi and 1.0% for RBC. The probability of survival was above 98% for both restorations in the first 6 years, however, it dropped to 60% for RBC by the end of the 15th year. For both materials the reasons for failure included secondary caries, restoration fracture, and endodontic complication. In addition, LidiSi also failed due to tooth fracture, while RBC due to marginal gap formation and loss of retention. Among the evaluated risk factors, material of restoration (OR=6.8, CI:3.1-14.9), oral hygiene (OR=8.0, CI: 2.9-22.1], and bruxism (OR=1.9, CI: 1.1-3.3) showed a significant impact on the evaluated criteria.
SIGNIFICANCE
LidiSi and RBC restorations showed similarly excellent 6-year survival, however, in the long term significantly more failures should be expected for RBCs.
Topics: Humans; Retrospective Studies; Dental Restoration Failure; Dental Porcelain; Composite Resins; Dental Materials; Ceramics; Inlays
PubMed: 37821330
DOI: 10.1016/j.dental.2023.10.017 -
Cureus Sep 2023A posterior tooth's occlusal surfaces and the proximal surface can be restored by using an inlay, which is an intra-crown cast reconstruction without affecting the cusps...
BACKGROUND
A posterior tooth's occlusal surfaces and the proximal surface can be restored by using an inlay, which is an intra-crown cast reconstruction without affecting the cusps of the tooth. When an inlay is prepared using an indirect approach, issues with traditional filling approaches, including poor morphology of the occlusal aspect or proximal aspect, inadequate resistance to wear, or subpar mechanical qualities of the directly inserted filler substance, are overcome.
AIM
The current study was conducted in order to compare and assess the resistance to fracture of dental materials used in the preparation of inlay restorations indirectly, like composite restorations prepared by laboratories indirectly, inlays formed indirectly of monolithic translucent ceramic derived from zirconia, and inlays formed indirectly of traditional monolithic ceramic derived from zirconia.
METHODS AND MATERIALS
For the investigation, 100 human premolars of the maxilla that were extracted recently were chosen. A self-polymerizing acrylic resin was used to incorporate the tooth roots in a band made up of polyvinyl chloride up to 2 mm below the cement-enamel junction. The dimension of the band was 1.3 cm by 1.9 cm. Five categories of 20 specimens of such teeth were formed. Category one, featuring teeth in good condition, acted as the positive control category. The remaining four categories of teeth received inlay tooth preparation. The research samples underwent thermocycling after having been preserved for a full week following the cementation of inlay replacements. Then, in a universal testing apparatus, every sample endured axial compressive force with a metal globe delivered vertically at a crosshead rate of 1 mm/minute. The amount of force necessary to cause a fracture was measured in Newtons (N).
RESULTS
The mean values of resistance against fracture in specimens in categories 1-5 were 1208.87 N, 614.89 N, 733.05 N, 1179.14 N, and 1148.49 N, respectively. The values of fracture resistance in specimens where an inlay cavity preparation was done but not filled were lower than those in traditional monolithic ceramic derived from zirconia and tooth specimens with inlays formed of monolithic translucent ceramic derived from zirconia, and the difference was significant statistically (p=0.001). The values of fracture resistance in composite inlay restorations prepared by laboratories were indirectly lower than those of monolithic ceramic derived from zirconia and tooth specimens with inlays formed of monolithic translucent ceramic derived from zirconia, and the difference was significant statistically (p=0.004).
CONCLUSION
Within the constraints of the current investigation, we can state that indirect zirconia-based ceramic products offer adequate fracture resistance, but additional research is needed to determine how well these materials hold up under different types of pressures before employing them in clinical tooth restoration.
PubMed: 37809271
DOI: 10.7759/cureus.44711 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Oct 2023This study aimed to explore the stress distribution of surface-mounted inlays with two ceramic materials and different strategies for fiber post-restoration on...
OBJECTIVES
This study aimed to explore the stress distribution of surface-mounted inlays with two ceramic materials and different strategies for fiber post-restoration on pulp-penetrating non-carious cervical lesion in a maxillary first premolar to provide minimally invasive and reasonable restorative methods.
METHODS
The cone beam computed tomography data of the standard right upper first premolar were selected. Healthy control (HC) and defective control (DC) finite element models were established. Then, eight experimental models were established according to two different ceramic materials (IPS e.max CAD [LD] and Lava Ultimate [LU]) and different locations of fiber post (without fiber post [NP], fiber post in buccal root canal [B], fiber post in palatal root canal [P], fiber post in both root canals [BP]), namely, LD, LD, LD, LD, LU, LU, LU, and LU. Axial load F1 and lateral load F2 were applied. Maximum principal stress and displacement of the buccal tip were investigated using finite element analysis software. Then, the percentage change of the following indicators in each experimental group was analyzed: stress of defective tip with group DC, stress of enamel and dentine, and displacement of buccal tips with group HC. It was considered similar when the percentage change was less than 5%.
RESULTS
LD and LU groups could effectively reduce the stress of the defective tip, but the decreasing amplitude in the former was greater than that of the latter. For the stress of surface-mounted inlays and resin adhesive layer, LD groups were higher than LU groups, and no significant difference in stress peak was found among different experimental groups in the same material. In addition, fiber posts in double root canals could significantly reduce buccal tip displacement.
CONCLUSIONS
For pulp-penetrating non-carious cervical lesions, the restorative strategy of surface-mounted inlays could be applied. Compared with Lava Ultimate, IPS e.max CAD could better protect the defective tip tooth. Furthermore, fiber posts in double root canals could decrease overall deformation and increase the retention of surface-mounted inlays.
Topics: Inlays; Finite Element Analysis; Composite Resins; Bicuspid; Ceramics; Dental Stress Analysis
PubMed: 37805678
DOI: 10.7518/hxkq.2023.2023123 -
Journal of Functional Biomaterials Sep 2023Dental ceramics are susceptible to slow, progressive crack growth after cyclic loading. The purpose of this study was to investigate the progressive patterns of cracks...
Dental ceramics are susceptible to slow, progressive crack growth after cyclic loading. The purpose of this study was to investigate the progressive patterns of cracks in two different types of CAD/CAM ceramic materials used with three different partial posterior indirect restoration (PPIR) designs and to determine the materials' failure risk using a fatigue test. Standard initial cracks were formed in Standard Tessellation Language (STL) files prepared for three different PPIRs. The materials chosen were monolithic lithium disilicate (LS) and polymer-infiltrated ceramic networks (PICNs). The extended finite element method (XFEM) was applied, and the fatigue performance was examined by applying a 600 N axial load. The cracks propagated the most in onlay restorations, where the highest displacement was observed. In contrast, the most successful results were observed in overlay restorations. Overlay restorations also showed better fatigue performance. LS materials exhibited more successful results than PICN materials. LS materials, which can be used in PPIRs, yield better results compared to PICN materials. While inlay restorations demonstrated relatively successful results, overlay and onlay restorations can be specified as the most and the least successful PPIR types, respectively.
PubMed: 37754898
DOI: 10.3390/jfb14090484 -
Polymers Aug 2023The thinking about metallic replacement has begun in a global context of reducing metallic alloys' use in odontology. Among the materials proposed for their replacement,...
The thinking about metallic replacement has begun in a global context of reducing metallic alloys' use in odontology. Among the materials proposed for their replacement, poly(etheretherketone) may present interesting properties, especially in removable dentures' frames. The purpose of this study is to evaluate fracture resistance of PEEK posts-and-cores compared to non-metallic CAD/CAM materials and fiber glass posts. Forty extracted maxillary central incisors were prepared to receive posts. Samples were divided into four groups depending on whether they had been reconstructed with LuxaCam PEEK, Enamic, Numerys GF or LuxaPost. Samples were submitted to an oblique compressive test and results were statistically analyzed with ANOVA and Student's tests (or non-parametric tests depending on the conditions). Glass fiber posts and Numerys GF reveal a significantly higher fracture resistance than LuxaCam PEEK and Enamic. No exclusively dental fracture has been noted for the Enamic group, which significantly distinguishes these samples from the three other groups. In our study, it appears that the conception of posts and cores with hybrid ceramic never conducts to a unique tooth fracture. By weighting the results according to the materials used, our data, obtained for the first time on this type of PEEK block, cannot confirm the possibility of using PEEK for inlay-core conception, excepted for specific cases when the material is considered in a patient presenting allergies or systemic disease contraindicating resin or metal.
PubMed: 37688208
DOI: 10.3390/polym15173583 -
Materials (Basel, Switzerland) Aug 2023Pathological tooth wear is an escalating social problem. Occlusal veneers can be an alternative to traditional prosthetic restorations such as crowns, inlays, and onlays.
UNLABELLED
Pathological tooth wear is an escalating social problem. Occlusal veneers can be an alternative to traditional prosthetic restorations such as crowns, inlays, and onlays.
BACKGROUND
The aim of this study is to assess the fracture resistance of occlusal veneers made of various materials depending on their thickness.
METHODS
In total, 120 occlusal veneers were examined. The restorations were made of four ceramics: leucite LC (IPS Empress Esthetic), hybrid HC (Vita Enamic), lithium disilicate LDC (IPS e.max Press), and zirconium oxide ZOC (Ceramill Zolid HT). A total of 30 veneers were made of each material, 10 for each of the three thicknesses: 1 mm, 1.5 mm, 2 mm. The restorations were cemented on identical abutments duplicated from the developed phantom tooth 35 (KaVo) with composite cement (All Bond Universal). The samples prepared in this way were subjected to a compressive strength test in a universal testing machine. Statistical analysis of the results was performed.
RESULTS
The average fracture resistance of occlusal veneers made of zirconium oxide ceramic was 1086-1640 N, of lithium disilicate ceramics 456-1044 N, of hybrid ceramics 449-576 N, and of leucite ceramics 257-499 N.
CONCLUSIONS
Occlusal veneers made of ceramics, zirconium oxide and lithium disilicate, had the highest resistance to fractures. Restorations made of leucite ceramics turned out to be the least resistant to forces. The greater the thickness of the ceramic occlusal veneers, the greater their fracture resistance.
PubMed: 37687699
DOI: 10.3390/ma16176006