Full Crown Research Articles

Bite force evaluation at maximal intercuspal position: An in vivo comparative study between stainless steel and zirconia crowns on primary molar teeth.

The objective of this study was to clinically evaluate and compare the mean bite force changes at maximum intercuspal position, along with parental satisfaction following full crown restoration using stainless steel crown/zirconia crown on primary molar teeth using digital occlusal analysis system T-Scan III (Tekscan Corp, Boston, Mass., USA). Thirty-six primary molars of children aged 6-9 years with pulpal involvement were selected for the study. The selected teeth were allocated to either of the two groups using simple random sampling technique: Group A = stainless steel crowned teeth and Group B = zirconia crowned teeth. The mean bite force was recorded before the placement of the crown, after the placement of the crown, and after 1 month-follow-up. The inter-group and intra-group comparison was done among the groups. After the placement of the crown, parents were asked to fill out a questionnaire for assessing parental satisfaction. A significant result in the bite force on crowned tooth, vertical dimension was seen from baseline to 1-month follow-up between the SSC and zirconia groups. In the zirconia crown group, the mean bite force was more compared to the stainless steel crown group. Parents' satisfaction was higher with zirconia crown in terms of color and esthetics. SSC is more acceptable than zirconia crown since occlusal re-equilibration was attained better in SSC as compared to zirconia crown.

ENDOCROWN: A SUBSTITUTE APPROACH TO POST AND CORE FOR REHABILITATION OF ENDODONTICALLY TREATED TOOTH

Restoration of endodontically treated teeth (ETT) is distinct from root canal treatment although they are mutually dependent in planning, treatment and prognosis. The fabrication of full coverage crowns with or without the use of posts remains the long-established means of restoration of endodontically treated teeth. Despite all the clinical success achieved with intraradicular posts, they have been criticized for removal of sound tissue and risk of root perforation. With the amelioration of adhesive techniques and invention of newer materials, the concept of endocrown has been considered as an alternative and viable method for restoration of root canal treated molars. It is an indirect monoblock restoration aimed to achieve a bonded biomimetic reconstruction. The preparation is simple following minimally invasive principles of adhesive dentistry compared to conventional crowns with post and core. They have the advantage of removing lower amounts of sound tissue compared to other techniques, and with much lower chair time needed. Also, the masticatory stresses received at the tooth/ restoration interface are more properly dissipated along the overall restored tooth structure when endocrowns are placed. The rationale of the preparation was to use surface area available in the pulp chamber to gain stability and retention through adhesive cementation. The supragingival positioning of restorative margins prevents interferences with periodontal tissues. This article highlights a case report where a porcelain fused to metal endocrown is fabricated to effectively manage a grossly mutilated endodontically treated tooth and was followed up for one year.

Impact of Full Veneer Crown Restoration on the Periodontal Health of Posterior Teeth

Background: Periodontal health plays a vital role in the longevity of prosthodontic restorations. Full veneer crown (FVC) is one of the most common modalities in restoration of single tooth for preservation of function and health of oral tissues. Objectives : The study was done to critically evaluate the impact of FVC restoration providing standard procedures on the periodontal health of posterior teeth, also to observe the changes of periodontal health in terms of their status of gingival index, plaque index, periodontal pocket depth, bleeding on probing in different stages of treatment. Materials & Methods: This prospective study evaluated the impact of FVC on periodontal health of 30 endodontically treated posterior teeth with FVC and 30 contralateral natural teeth of 19 patients in different stages of treatment for 2 years duration in the Dept. of Prosthodontics, Bangabandhu Sheikh Mujib Medical University (BSMMU) Hospital. To assess the periodontal health gingival index, plaque index, periodontal pocket depth, bleeding on probing were used. Collected data were analyzed using SPSS software (version 22) according to the study Objectives Results: The study Result showed that the mean differences of gingival index and plaque index between abutments and contraleteral natural teeth were non significant (p > 0.05) at baseline, 4th month visit; but the differences were significant (p < 0.05) at 8th month, 12th month visits. Regarding periodontal pocket depth the mean differences between abutments and contraleteral natural teeth found non significant (p > 0.05) throughout the follow up period. Same thing observed in bleeding on probing except 12th month follow up visit, where highly significant (p < 0.01) mean differences observed. Also the study found that the gingival index, plaque index, bleeding on probing, periodontal pocket depth increased a bit in 4th,8th,12th month visits gradually in abutments, which was almost same in contralateral natural teeth in case of gingival index, periodontal pocket depth; and increased a bit in case of plaque index, bleeding on probing. Conclusion : If the FVC is fabricated maintaining all standard procedures equigingival margin with proper marginal adaptation, oral hygiene as well as general health of the patient is maintained although less but there is a chance of detrimental effects on periodontal health in comparison to contralateral natural teeth. J Bangladesh Coll Phys Surg 2023; 41: 46-52

The effect of thermo-cycling on fracture strength of 3D printing and PMMA interim prostheses

Aim of the study: This study compared the fracture resistance of three-dimensional printing (3D) interim restoration with that polymethylmethacrylate (PMMA), interim restoration.
 Materials and methods: In the present study upper molar (dentoform) tooth was prepared for full coverage crowns. The prepared model was digitally scanned by extra-oral scanner. Duplication of the master die into metal dies (chrome cobalt alloy). Totally, 40 samples were divided into two groups (20) using 3D printing (asiga dentatooth resin material), and (20) Polymethylmethacrylate PMMA (integra) resin material. Ten samples from each group were subjected to thermo-cycles (1250 cycles, 5-55 °C). The fracture resistance was then measured for all samples with a universal testing machine.
 Results: In SPSS, the mean ± Stander deviation values of fracture resistance were recorded for the acrylic PMMA group before thermo-cycling (1703.30 ±376.659 Newton) and after thermo-cycling (1460.30 ±364.260 Newton), while the mean ± Stander deviation values were recorded for 3D printing group before thermo-cycling (1972.50±399.181 Newton) and after thermo-cycling ( 2284.10±239.001Newton). It was found that 3D printing recorded a significantly higher fracture resistance mean than PMMA groups.
 Conclusion: 3D printing interim prostheses recorded higher fracture resistance compared with PMMA interim prostheses.

Gold versus ceramic - which will last longer for posterior indirect restorations?

Data sources Electronic search through PubMed (Medline), CENTRAL (Cochrane) and Embase databases in November 2021. Grey literature searches (OpenGrey, Pro-Quest, National research register and the register of clinical studies hosted by the US National Institute of Health).Study selection Randomised in vivo clinical trials (RCTs) with at least two-year follow-ups, that compared the longevity of adhesively luted indirect ceramic restorations against conventionally cemented indirect metal restorations. The teeth studies had to be about single tooth restorations, on premolars or molars, with sufficient information available for extraction; eg outcome assessment, reason for failure. No language or time restrictions were applied.Data extraction and synthesis Two authors performed study selection, data extraction and quality assessment independently and in duplicate. The following clinical data was extracted: number of participants and dental health status, location of the cavosurface margin, cavity type, reason for intervention, methods and materials for treatment, follow-up, lesion activity at moment of restoration placed, lesion extension (surfaces of restoration), lesion margin (enamel or dentine). It was decided if the restoration was renewed, repaired or re-cemented, then this was classed as outcome failure. Grading of evidence was performed according to the GRADE network.Results After duplicates were removed, 2,667 underwent title screening, 389 abstract screening, and 186 went on to have full text screening with 72 being excluded. In total, 110 eligible articles were then excluded from the 114 that were assessed leaving four RCTs meeting the eligibility criteria and being included in the synthesis, published between 2000 and 2013. Two studies were parallel-arm, the other two, split-mouth design. Overall, 443 restorations had been placed, 212 were adhesively luted ceramic, and 213 conventionally cemented metal restorations; these were all gold. The follow-up periods ranged from 5-7 years. Two studies compared inlays only, one looked at partial crowns only, and the fourth full crowns. The lowest failure rates were found for metal restorations, ranging from 0-11%. The failure rates for ceramic inlays and partial crowns were 5-9% over the same observation period. The failure rates for ceramic full crowns were 36% after five years. The most common failure for ceramic was found to be fracture of the restoration, whereas caries was the most frequent cause of failure for the gold restorations.Conclusions The risk of bias was high for all four studies and the grading of evidence showed a low level of evidence. Only one meta-analysis could be performed comparing conventionally cemented metal vs adhesively luted ceramic restorations, showing the relative risk to fail for conventionally cemented metal indirect restorations is significantly lower than adhesively luted ceramic indirect restorations.

Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar

BackgroundThe purpose of this study was to investigate the fracture strength and stress distribution of four ceramic restorations.MethodsForty human mandibular first molars were collected and randomized into four groups after establishing the distal defect: full crown group with 4 mm axial wall height (AWH) (FC4); short AWH crown group with 2 mm AWH (SC2); occlusal veneer group with 0 mm AWH (OV0); occlusal distal veneer group with only the distal surface prepared, and 4 mm AWH (OD4). The teeth were prepared according to the groups and the ceramic restorations were completed using celtra duo ceramic blocks. The ceramic thickness of the occlusal surface is about 1.5 mm and the edge is about 1 mm. The failure load values and fracture modes of each group were detected by mechanical test in vitro. According to the groups to establish three-dimensional finite element analysis (FEA) models, a 600 N loading force was applied vertically using a hemispherical indenter with a diameter of 6 mm. and compare the stress distribution under the condition of different restorations.ResultsIn vitro mechanical tests showed that the failure load values were SC2 (3232.80 ± 708.12 N) > OD4 (2886.90 ± 338.72 N) > VO0 (2133.20 ± 376.15 N) > FC4(1635.40 ± 413.05 N). The failure load values of the short AWH crown and occlusal distal veneer were significantly higher than that of occlusal veneer and full crown (P<0.05). The fracture modes of the full crown and occlusal veneer groups were mainly ceramic fractures and some were restorable tooth fractures. The short AWH crown and occlusal distal veneer groups presented with three fracture modes, the proportion of non-restorable tooth fracture was higher. The results of FEA show that under the spherical loading condition, the stress of ceramic was concentrated in the contact area of the loading head, the maximum von Mises stress values were FC4 (356.2 MPa) > VO0 (214.3 MPa) > OD4 (197.9 MPa) > SC2 (163.1 MPa). The stress of enamel was concentrated in the area where the remaining enamel was thinner, the maximum von Mises stress values was OD4 (246.2 MPa) ≈ FC4 (212.4 MPa) > VO0 (61.8 MPa) ≈ SC2 (45.81 MPa). The stress of dentin is concentrated in the root furcation and the upper third region of the root. However, stress concentration was observed at the tooth cervix in the full crown.ConclusionUnder certain conditions, the occlusal distal veneer shows better performance than the full crown.

Post-Fatigue Fracture Resistance of Lithium Disilicate and Polymer-Infiltrated Ceramic Network Indirect Restorations over Endodontically-Treated Molars with Different Preparation Designs: An In-Vitro Study

The aim of the present study was to evaluate the fatigue to cyclic and static resistance of indirect restorations with different preparation designs made either of lithium disilicate (LS) or polymer-infiltrated ceramic network (PICN). Eighty-four (n = 84) molars were chosen, endodontically treated, and prepared with standardized MOD cavities. The molars were randomly divided into 6 study groups (n = 14) taking into account the "preparation design'' (occlusal veneer with 1.2 mm occlusal thickness; overlay with 1.6 mm occlusal thickness; adhesive crown with 2 mm occlusal thickness) and the "CAD/CAM material'' (E-max CAD, Ivoclar vivadent; Vita Enamic, Vita). A fatigue test was conducted with a chewing simulator set at 50 N for 1,500,000 cycles. Fracture resistance was assessed using a universal testing machine with a 6 mm diameter steel sphere applied to the specimens at a constant speed of 1 mm/min. A SEM analysis before the fracture test was performed to visually analyze the tooth-restoration margins. A statistical analysis was performed with a two-way ANOVA and a post-hoc pairwise comparison was performed using the Tukey test. The two-way ANOVA test showed that both the preparation design factor (p = 0.0429) and the CAD/CAM material factor (p = 0.0002) had a significant influence on the fracture resistance of the adhesive indirect restorations. The interaction between the two variables did not show any significance (p = 0.8218). The occlusal veneer had a lower fracture resistance than the adhesive crown (p = 0.042) but not lower than the overlay preparation (p = 0.095). LS was more resistant than PICN (p = 0.002). In conclusion, in the case of endodontically treated teeth, overlay preparation seems to be a valid alternative to the traditional full crown preparation, while occlusal veneers should be avoided in restoring non-vital molars with a high loss of residual tooth structure. LS material is more resistant compared to PICN.

The Effect of Thermocycling on Fracture Resistance of CAD- CAM and 3D Printing Provisional Prosthesis

This study aims to assess how thermal cycling affected the fracture strength of temporary restorations made using additive 3D printing procedures and computer-aided design- computer-assisted manufacturing (CAD/CAM), subtractive (milling) methods. For full coverage crowns, a dento form upper molar tooth was created. A second oral scanner digitally scanned developed model. Duplication of the metal dies was made using the master die (chrome cobalt alloy). A total of 40 samples were created and split into two groups: 20 were created using CAD/CAM technology with a (Bilkim) CAD PMMA disc and 20 were created using 3D printing with Asiga dentatooth resin. Thermal cycles (1250 cycles, 5-55 °C) were applied to 10 samples from each group. After that, a universal testing device determined the fracture resistance for each sample. The mean with standard deviation values of fracture resistance were recorded for the milled group before thermocycling (560.50 ±83.581 newton) and after thermocycling (901.00± 311.598 newton) meanwhile the mean ± stander deviation value was recorded with the printed group before thermocycling (1972.50±399.181 Newton) and after thermocycling (2284.10±239.001 Newton), it was found that the printed group recorded statistically significant higher fracture resistance mean value than the milled group. Provisional crowns constructed using the 3D printing technique showed higher fracture resistance compared to the temporary milled crowns.

Complete oral rehabilitation with direct and indirect composite resins: a minimally invasive approach on severely compromised teeth.

The rehabilitation of severely worn teeth is a complex challenge for dental practitioners. There are many different types of dental materials and restorative techniques, and there is not a single way to achieve the desired result. This clinical report demonstrates a complete oral rehabilitation with composite resins when using an indirect application and direct techniques, with the support of the Lucia Jig technique, the Willis technique, and diagnostic waxing for the vertical dimension correction. The wide clinical improvement was achieved with the recovery of the function, the esthetics, and the increase of vertical dimension of occlusion through the planned treatment. The proposed treatment maintained the natural teeth, without the intense wear by the application of the composite resins instead of ceramics, together with excellent conditions for the patient to control the posttreatment and extend the durability, with the correct follow-up of appointments. Young patients with extensive dental wear and the loss of vertical dimension should not be directly submitted to ceramic treatments, with preparations for full crowns. Oral rehabilitation using composite resins, either directly or indirectly, allows for the recovery of the function and esthetics, without the intense predictable dental wear, and reduced financial investment.

Three-Dimensional Finite Element Analysis of Worn Molars With Prosthetic Crowns and Onlays Made of Various Materials

Background/Purpose Restoration of worn teeth represents a challenge for practitioners in terms of preserving dental tissues, achieving restoration requirements, and choosing the most appropriate material. This study aimed to evaluate the effect of both preparation and restoration type on stress distribution in modeled first mandibular molars when functional and parafunctional occlusal forces were applied. Materials and methods The study sample consisted of 40 three-dimensional computer models of restored lower first molars with full crowns (gold, nickel-chrome,lithium disilicate, BruxZir® zirconia, and porcelain fused to metal) and onlays (gold,nickel, chrome, lithium disilicate, and direct and indirect composites). Forces of different intensities and directions were applied, and then finite element analysis was carried out based on the von Mises equivalent stress theory to predict the failure that could occur in the restoring materials and luting cement or bonding agent. Results In functional forces groups, zirconia crowns showed the lowest value of the failure risk, while the highest value was in veneering porcelain with values close to the rest of the models. For onlays, gold onlays represented the best stress distribution with the lowest value of the failure risk, in contrast to the composite onlays that had the highest failure risk. In parafunctional forces groups, the preference remained for zirconia and gold crowns, as well as for metal onlays, with greater differences in the values of the failure risk. Conclusion Gold alloy exhibited better behavior in the stress distribution. All restorations showed similar behavior when applying functional forces; however, when applying parafunctional forces, both gold and zirconia crowns have shown the best results.

Comparative evaluation of retention of lithium disilicate crowns with four different cementation systems- An in-vitro Study

AIM OF THE STUDY: This in vitro study was performed to compare the retention of pressable lithium disilicate crowns cemented with four different cementation systems.METHODS: Eighty single rooted maxillary 1st premolars were collected after excluding teeth with caries and/or previous restorations. Preparation of the samples was standardized by using a diamond bur mounted onto a surveyor. An anatomic crown was waxed on each tooth and then hot pressed using lithium disilicate ceramic (IPS e.max PRESS, IvoclarVivadent). The samples were randomly divided into 4 groups (n = 20) according to different cementation systems. Each group sample was subjected to a seating force of 50N using universal testing machine. Each upper block was pulled along the path of insertion of the crown with a crosshead speed of 1mm/min.RESULTS: Self adhesive resin cement showed the maximum tensile strength among all adhesive luting cements (2.65 MPa). Self etch resin cement group showed mean tensile strength of (1.78 MPa) that was marginally less than total etch resin cement (1.86 MPa). Glass ionomer cement exhibited least tensile strength (1.41 MPa) compared to the other three luting cements.CONCLUSION: Within the limitations of this in vitro study, it was concluded that lithium disilicate full coverage crowns cemented with self adhesive resin cement showed higher bond strength followed by total etch resin cement, self etch resin cement and glass ionomer cement.

A successful, temporary, pragmatic, emergency management of dislodged crowns

Full crowns are often used as treatment in dentistry. Dislodgement of a crown may occur at any time if a negative tensile force on the crown allows displacement. Keeping the displaced crown in situ is problematic, as the crown tends to come off the stump,may be lost and or swallowed. Emergency refixing is often not feasible or available. This note suggests an easy, successful,emergency management of temporarily refixing the crown with sugarless chewing gum until the crown can be recemented by a dentist.

Evaluation of the fracture resistance and failure types of different CAD-CAM ceramic crowns supported by angled titanium abutments.

To evaluate the fatigue resistance of computer-aided design and computer-aided manufacturing (CAD-CAM) single-ceramic crowns which were applied on angled implant abutments after thermomechanical aging. Titanium abutments (N = 72, MODE Medical Dental Implant, Turkey) with three different angles (0˚, 15°, and 25°) were restored using different materials (monolithic zirconia [Zir], lithium silicate ceramic reinforced by zirconia [VS], and hybrid ceramic [VE]). Crowns in the maxillary first premolar form were cemented to abutments using resin cement (Panavia 2.0 Introkit). Dynamic loading and thermomechanical aging were applied to the specimens (120,000 cycles, 49N, 5-55°C). Fracture resistance values were measured in the universal test machine and fracture types were determined. Two-way ANOVA and Tukey test were used for statistical analysis (Jamovi version 2.3.5). Both the abutment angle and the type of material had a significant effect on fracture resistance (F = 3.295, p<0.05). The highest fracture resistance was obtained in Group 0˚-Zir, and the lowest fracture resistance was obtained in Group 15˚-VE. Fracture resistance showed significant differences between Group 0˚ and Group 15˚ for the Zir and VE materials, and between Group 0˚ and Group 25˚ for VS (p<0.05); no statistical significance was determined between the other groups (p>0.05). When failure types were evaluated, they were seen to be full or partial crown fractures, and abutment deformation was found in some samples. Monolithic crowns may be preferred on angled abutments. The fracture resistance of CAD-CAM materials decreases as the angle of abutments increases. Monolithic zirconia has higher fracture resistance than other materials.

Implementation of CAD/CAM program in a nonface-to-face classroom environment due to the COVID-19 pandemic.

This study aimed to evaluate a nonface-to-face crown designing module in a preclinical dental course. Free dental planning software (Blue Sky Plan) was installed on the personal computers of dental college students, and a #46 full veneer crown designing practice was performed individually. An online survey was conducted on the computers' specification and main usage of the students, the practice process, and results. Statistical analysis was conducted to analyze the association between variables, such as "operating system," "central processing unit ," "number of cores," "random-access memory (RAM)," "graphic card," and task performance. Of the D2 students, 75.4% (52 of 69) responded to the survey. Overall, 96% of the respondents used their computers, and all respondents had no problem running the program. Most of the students marked their level of computer literacy as intermediate and had purchased the computers for the purpose of performing light work. The most common specifications of the computer were Intel i5, quad core, 8 GB RAM, and Windows 10. Students had little experience with computer-aided design/computer-aided manufacturing before the class. The relationship between computer specifications and task performance was not statistically significant. Overall, students with intermediate-level computer literacy used computers with less than the recommended specifications of the program; however, they were able to run the program and individually proceed with modules to submit results. Using an individually available crown designing program can provide an opportunity to diversify curricula and broaden students' perspectives even under circumstances like the COVID-19 pandemic that limits intimate face-to face classes.

Accuracy of Models Fabricated by a Chair-side Fused Deposition Modeling (FDM) Printer in Stomatology.

To establish a method to improve the accuracy of a dental chair-side fused deposition modelling (FDM) printer and assess the internal adaptation of full crown casting patterns produced by the FDM printer. A Lingtong dental three-dimensional (3D) printer (Beijing SHINO Company, China), was used to fabricate six cubes. Deviation analysis was performed between the 3D scanned data and the designed cube data. Fifteen crowns (Group LT) of the right maxillary first molar were printed. A DDP 3D printer (Group EV) and a milling machine (Group ZT) were used to produce the same crowns as controls. Compared with the designed cube, the 3D deviation of 73.75% points was within 0.1 mm. The calibration parameters (CP) of the X, Y, and Z directions were 1.005, 0.998, and 1.000, respectively. Based on the CP, the X and Y directions of the printer were adjusted in the software to compensate for the mechanical errors. The crowns were fabricated using different types of equipment to evaluate the accuracy of printing by the 3D dental printer. The internal gap of each crown was measured using a silicone replica and the 3D analysing method. In Group LT, the internal gap of the marginal, axial, and occlusal areas were 0.030 ± 0.019, 0.092 ± 0.019, and 0.023 ± 0.009 mm, respectively. In the marginal and occlusal areas, Group EV exhibited the smallest internal discrepancy, whereas in the axial area, Group ZT achieved the smallest. Only LT and ZT achieved internal spaces in the marginal area without statistical significance to the prescribed parameters (p>0.05). The crown cannot be placed on the preparation if the printer is not calibrated. This study revealed the inability to produce full crown casting patterns with similar internal adaptations using different machines for fabrication. None of the three groups could reproduce the prescribed internal space. Combined with CAD/CAM technology, 3D printing technology has been gradually applied in stomatology.

Management of Fractured Endodontically Treated Tooth by Fibre Optic Composite Post-Core-Crown: A Case Report

The restoration of endodontically treated tooth is a subject that has been evaluated and discussed widely in the dental literature. The goal of dental treatment is to provide optimal oral health, aesthetics and functions. The successful treatment of a badly broken endodontically treated tooth depends not only on the success of the endodontic treatment but also on good prosthetic reconstruction. The prosthetic treatment on a seriously damaged, endodontically treated tooth often requires an endodontic post as an additional retention element for core build up prior to crown restoration. This case report presents a male patient of 22 years of age with prosthetic crown fracture of endodontically treated maxillary left central incisor tooth. The following clinical case represents the clinical steps involved in the utilization of a fibre-reinforced composite post-core in a maxillary left central incisor and the subsequent treatment with a full veneer crown.&#x0D; Central Medical College Journal Vol 5 No 2 Jul 2021 PP 126-130

Assessment of relative translucency and resultant color of contemporary resin-matrix ceramics indicated for laminate veneers and full crowns.

Evaluation of the optical properties of restorative materials is an important parameter for identifying clinical success. The aim of this study was to compare the translucency of contemporary resin-matrix ceramics (RMCs) and to evaluate the effect of cement shade on the final color of RMCs indicated for laminate veneers and full crowns. A hundred A2 shade RMC specimens were fabricated by using Mazic Duro (MD), CAMouflage NOW (CN), KZR-CAD HR2 (KZR), Grandio Block (GB), and Brilliant Crios (BC) at 0.7-mm and 1.5-mm thicknesses (n = 10). A2 shade composite resin was used for the foundation structure. Twenty resin-cement specimens were prepared from A2 and translucent shades at 0.1-mm thickness. Interchangeably, the foundation-cement-resin matrix ceramic assemblies were created with optical gel. The color coordinates were recorded using a spectrophotometer. After calculating translucency parameter (TP00) and color difference (ΔE00) values, data were analyzed statistically (P = 0.05). TP00 values were influenced by RMC type and thickness. TP00 values of RMCs can be listed in descending order as MD>GB = CN>BC=KZR. ΔE00 values were significantly influenced by all parameters and their interactions. MD exhibited higher ΔE00 values among tested RMCs. The effect of A2 cement was not perceived visually while TR cement demonstrated visually perceptible but clinically acceptable values for both laminate veneers and full crowns. As the material thickness decreased, the TP00 and ΔE00 values increased in all RMCs. Clinicians should carefully prefer cement shade and RMC material by contemplating their impact on the optical properties particularly when the restoration is thin.

Treatment of Tooth Wear Using Direct or Indirect Restorations: A Systematic Review of Clinical Studies.

Tooth wear is considered a well-developed issue in daily clinical practice; however, there is no standard protocol for treatment. The aim of this manuscript was to systematically review the literature to evaluate the clinical outcomes of direct or indirect restorations for treating tooth wear. A literature search was conducted through the PubMed MedLine, Scopus, ISI Web of Science, Scielo, and EMBASE databases up to 29 April 2022. Clinical studies evaluating the clinical performance of direct or indirect restorations for treating tooth wear for a minimum follow-up of 6 months were included in the review. A total of 2776 records were obtained from the search databases. After full-text reading, 16 studies were included in the qualitative analysis. Considering the high heterogenicity of the studies included, a meta-analysis could not be performed. All studies included the rehabilitation of anterior and posterior teeth with extensive wear, using both indirect and direct restorations for a maximum follow-up of 10 years. Restoration materials included ceramo-metal crowns, full gold crowns, lithium disilicate ceramic, zirconia, polymer infiltrated ceramic networks, and resin composites. Most of the reports assessed the survival rate of the restorations and the clinical features using the United States Public Health Service (USPHS) Evaluation System criteria. Contradictory discoveries were perceived concerning the type of restoration with better clinical performance. Considering the current literature available, there is no evidence in the superiority of any restoration technique to ensure the highest clinical performance for treating tooth wear.

Fixed prosthodontics clinical unit completions in an undergraduate curriculum: A 10-year retrospective study.

Providing undergraduate dental students with a range of clinical experiences in fixed prosthodontics procedures is an important component of dental education. The aim of this retrospective study was to analyse the types of laboratory-fabricated fixed prosthodontics clinical units completed by undergraduate students over 10 consecutive years and determine any significant trends. The fixed prosthodontics treatment registers from 2012 to 2021 were reviewed and the different types of completed fixed prosthodontics units and total number of fixed prosthodontics units were recorded for each year. Completed units were categorised according to the type of restoration and expressed in whole numbers and as a percentage of the total number of units completed in each year. The data were presented in table and graph form. Mann-Kendall tests were performed to statistically analyse for trends in the different restoration types. Throughout all study years, porcelain bonded to metal (PBM) crowns (48.25%, range 35.70%-59.91%) were the most frequently completed fixed prosthodontics unit followed by full gold crowns (FGC) (20.84%, range 14.89%-27.30%) and all-ceramic crowns (ACC) (12.70%, range 3.67%-24.41%). Collectively, PBM, FGC and ACC comprised 81.80% of all completed fixed prosthodontics units. There were observed trends of increased use of all types of all-ceramic containing restorations, all types of all-gold containing restorations, all types of partial coverage restorations and specifically ceramic onlays and gold onlays. There were observed trends of reduced use of cast gold post-cores and all types of bridges. PBM crowns were the mainstay laboratory-fabricated fixed prosthodontic unit completed over 10 years of undergraduate student fixed prosthodontics clinical practice.

Editorial: Is Zirconia the Holy Grail of All-Ceramic Restorations?

Editorial: Is Zirconia the Holy Grail of All-Ceramic Restorations?