Fracture Resistance of Remaining Buccal Cusps in Maxillary Premolar Ceramic Onlay Restorations

2020 ◽  
Vol 45 (6) ◽  
pp. 624-631
Author(s):  
I Thainimit ◽  
P Totiam ◽  
K Wayakanon
Keyword(s):  
Computer Aided Design ◽  
Fracture Resistance ◽  
Compressive Load ◽  
Compressive Force ◽  
Resin Cement ◽  
Tooth Structure ◽  
Partial Coverage ◽  
Cad Cam ◽  
Maxillary Premolars ◽  
One Year

Clinical Relevance Preparation designs for bondable partial coverage restorations are varied. As little as 1 mm of thickness of a remaining buccal cusp can be kept when restoring maxillary premolars with bondable partial coverage restorations. SUMMARY Indirect partial coverage restorations have become increasingly popular in recent years as new and improved adhesive materials have been developed. These restorations can preserve substantial amounts of tooth structure. However, there are some aspects of indirect partial coverage restorations for which no clear protocol exists. This study investigated the minimal thickness of the nonfunctional cusp that must be left in a bondable ceramic partial coverage restoration in order to resist compressive force. Ninety sound human maxillary premolar teeth were obtained and used in one of the following three ways. Ten of the sound teeth were used as a control without further preparation. Forty other sound teeth had cavities designed and were tested as “unrestored teeth.” The remaining 40 sound teeth received not only cavities but also restoration and were tested as “restored teeth.” Both the restored group and the unrestored group were prepared either with an overlay or with varying buccal cusp thicknesses of 1, 2, or 3 mm. In total, there were nine experimental groups with 10 in each group (n=10). The prepared teeth were digitally scanned, and the restorations were designed and fabricated from IPS e.max computer-aided design (CAD) software using a CAD/CAM machine (CEREC MC XL, Dentsply Sirona, Bensheim, Germany). The restorations were cemented with resin cement (Panavia V5). All samples underwent thermocycling and dynamic fatigue simulating approximately one year of actual use. All the teeth were then subjected to compressive load until the point of fracture, and the mode of each fracture was analyzed. Results show that the fracture resistance of the restored groups was significantly higher than the nonrestored groups (p<0.001) and the sound teeth (p<0.05). Crucially, this study determined that 1 mm of remaining buccal cusp thickness in bondable partial coverage restorations for maxillary premolars is sufficient to withstand normal use of the tooth without breakage.

scholarly journals Fracture Resistance and Microleakage of Endocrowns Utilizing Three CAD-CAM Blocks

2015 ◽  
Vol 40 (2) ◽  
pp. 201-210 ◽  
Author(s):  
HM El-Damanhoury ◽  
RN Haj-Ali ◽  
JA Platt
Keyword(s):  
Fracture Mode ◽  
Computer Aided Design ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Resin Cement ◽  
Blue Dye ◽  
Endodontically Treated Teeth ◽  
Modes Of Failure ◽  
Computer Aided ◽  
Cad Cam

SUMMARY This study assessed marginal leakage and fracture resistance of computer-aided design/computer-aided manufacturing (CAD/CAM) fabricated ceramic crowns with intracoronal extensions into the pulp chambers of endodontically treated teeth (endocrowns) using either feldspathic porcelain (CEREC Blocks [CB], Sirona Dental Systems GmbH, Bensheim, Germany), lithium disilicate (e.max [EX], Ivoclar Vivadent, Schaan, Liechtenstein), or resin nanoceramic (Lava Ultimate [LU], 3M ESPE, St Paul, MN, USA).). Thirty extracted human permanent maxillary molars were endodontically treated. Standardized preparations were done with 2-mm intracoronal extensions of the endocrowns into the pulp chamber. Teeth were divided into three groups (n=10); each group was restored with standardized CAD/CAM fabricated endocrowns using one of the three tested materials. After cementation with resin cement, specimens were stored in distilled water at 37°C for one week, subjected to thermocycling, and immersed in a 5% methylene-blue dye solution for 24 hours. A compressive load was applied at 35 degrees to long axis of the teeth using a universal testing machine until failure. Failure load was recorded, and specimens were examined under a stereomicroscope for modes of failure and microleakage. Results were analyzed using one-way analysis of variance and Bonferroni post hoc multiple comparison tests (α=0.05). LU showed significantly (p<0.05) higher fracture resistance and more favorable fracture mode (ie, fracture of the endocrown without fracture of tooth) as well as higher dye penetration than CB and EX. In conclusion, although using resin nanoceramic blocks for fabrication of endocrowns may result in better fracture resistance and a more favorable fracture mode than other investigated ceramic blocks, more microleakage may be expected with this material.

Conservative Anterior Partial Coverage CAD/CAM Restoration

2017 ◽  
Vol 42 (2) ◽  
pp. 117-121
Author(s):  
JT May
Keyword(s):  
Digital Technology ◽  
Computer Aided Design ◽  
Tooth Structure ◽  
Partial Coverage ◽  
Restorative Treatment ◽  
Minimally Invasive Dentistry ◽  
Computer Aided ◽  
Design And Manufacturing ◽  
Cad Cam ◽  
Aided Design

SUMMARY Computer-aided design and manufacturing technology enables practitioners to create, in a single appointment, indirect restorations that are esthetic and functionally unique to the patient's situation. The popular effort to perform minimally invasive dentistry using digital techniques with chairside milling can lead dentists to novel individualized restorative treatment. This article demonstrates a conservative anterior partial coverage restoration, utilizing both digital technology and chairside ceramic characterization to achieve an optimal esthetic outcome while preserving healthy tooth structure.

Effect of Ferrule and Bonding on the Compressive Fracture Resistance of Post and Core Restorations

2009 ◽  
Vol 10 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Marzieh Alikhasi ◽  
Hassan Dorriz ◽  
Ali Mirfazaelian ◽  
Tabbassom Hooshmand
Keyword(s):  
Fracture Resistance ◽  
Survival Rates ◽  
Testing Machine ◽  
Compressive Load ◽  
Fracture Pattern ◽  
Resin Cement ◽  
Endodontically Treated Teeth ◽  
Tooth Structure ◽  
Compressive Fracture ◽  
Post And Core

Abstract Aim The purpose of this study was to compare the fracture resistance of endodontically treated teeth restored with different post and core systems in combination with complete metal crowns in teeth with no coronal structure. Methods and Materials Fifty extracted mandibular premolars were divided into five groups. The coronal portion of each tooth was removed at the cementoenamel junction (CEJ) in all groups except Group 1. In this group the teeth were sectioned 1 mm above the CEJ to create a ferrule. After root canal preparations, cast posts were placed in the first four groups. Prefabricated glass fiber posts and composite cores were placed in the fifth group. An opaque porcelain layer was applied to the metal post surfaces in the third group and an alloy primer was applied to the posts in the fourth group before using Panavia F2 resin cement. No bonding agent or surface treatments were used for the first and second groups. A Ni-Cr full cast crown for each sample was prepared and cemented. A compressive load was applied at an angle of 45 degrees to the crown with a universal testing machine. After 500,000 mechanical cycles at 1.5Hz, the maximum load at fracture (N) was recorded. Results Significantly higher fracture resistance values (216.87 N) and survival rates (75%) were demonstrated for non-ferrule teeth restored with opaque layered posts than for other non-ferrule groups. The prefabricated post group showed the most favorable fracture pattern in all test groups (P=0.04). Conclusion Either a ferrule preparation or bonding with the use of an opaque porcelain layer can increase the fracture resistance of teeth with little remaining tooth structure that are restored with cast crowns following endodontic therapy. Clinical Significance Bonding cast posts to the tooth structure has a significant effect on compensating for the lack of a ferrule on endodontically treated teeth. Citation Dorriz H, Alikhasi M, Mirfazaelian A, Hooshmand T. Effect of Ferrule and Bonding on the Compressive Fracture Resistance of Post and Core Restorations. J Contemp Dent Pract 2009 January; (10)1:001-008.

scholarly journals CAD-FEA modeling and fracture resistance of bilayer zirconia crowns manufactured by the rapid layer technology

2021 ◽  
Vol 32 (3) ◽  
pp. 44-55
Author(s):  
Julia Magalhães Costa Lima ◽  
Anna Karina Figueiredo Costa ◽  
Lilian Costa Anami ◽  
Karina Barbosa Souza ◽  
Nathalia Ramos da Silva ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Fracture Resistance ◽  
Resin Cement ◽  
In Vitro Test ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Cement Interface ◽  
Computer Aided ◽  
Cad Cam

Abstract In the RLT (Rapid Layer Technology), veneering ceramic and framework are fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) and then cemented to obtain the restoration. This study aimed to evaluate the effect of the thickness of veneering ceramic manufactured by the RLT technique on the fracture resistance (FR) of bilayer crowns with zirconia frameworks. Twenty zirconia frameworks and twenty feldspathic posterior crowns with two different veneering ceramic occlusal thicknesses (1mm=TF1; 2mm=TF2) were manufactured using CAD/CAM system. The specimens were luted to an epoxy resin abutment with resin cement and mechanically cycled (200N and 4.5×105 Pa, 37°C, 2×106 cycles, 3Hz). The FR test was performed (10kN, 0.5mm/min), and the specimens were analyzed in a stereomicroscope. For the stress analysis (finite element analysis, FEA), a 10kN load was equal to the in vitro test, and the principal stress was evaluated. The FR data were analyzed by Student’s t-test and Weibull's analysis. The thickness influenced the FR of bilayer crowns. The FR was higher in the TF2 than in the TF1 group. The TF2 group presented the highest characteristic strength compared to the group TF1. The predominant type of failure was delamination. The FEA showed higher stress concentrations below the loading application point at the veneering cement interface in the 1-mm-thick model. The bilayer crowns manufactured using the approach of 2mm of veneering ceramic promoted higher FR compared to the group with 1mm veneering ceramic. Also, the FEA showed that the veneer ceramic thickness has an effect on stress distribution in zirconia-based bilayer crowns.

scholarly journals Fracture Resistance in Non-Vital Teeth: Absence of Interproximal Ferrule and Influence of Preparation Depth in CAD/CAM Endocrown Overlays—An In Vitro Study

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 436
Author(s):  
Lucía Barallat ◽  
María Arregui ◽  
Sandra Fernandez-Villar ◽  
Blanca Paniagua ◽  
Andrés Pascual-La Rocca
Keyword(s):  
Fracture Strength ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Compressive Force ◽  
Ample Evidence ◽  
Alveolar Crest ◽  
Cad Cam ◽  
Group A ◽  
Group B ◽  
Group D

There is ample evidence to support the use of endocrowns to restore endodontic teeth. However, the influence of the position of the interproximal margins on fracture strength has not yet been studied. The aim was to determine the relationship between the apicocoronal position of the interproximal restorative margins and fracture resistance in nonvital teeth restored with CAD/CAM endocrown overlays. Forty extracted human maxillary premolars were prepared for endocrown overlay restorations without ferrule on the interproximal aspects and classified according to the position of the interproximal restoration margins in relation to the alveolar crest: 2 mm (group A), 1 mm (group B), 0.5 mm (group C), and 0 mm (group D). Fracture strength was measured using a universal testing machine applying a compressive force to the longitudinal tooth axis. Group A had a mean fracture resistance of 859.61 (±267.951) N, group B 1053.9 (±333.985) N, group C 1124.6 (±291.172) N, and group D 780.67 (±183.269) N, with statistical differences between groups. Group C had the highest values for fracture strength compared to the other groups (p < 0.05). The location of the interproximal margins appears to influence the fracture resistance of CAD/CAM endocrown overlays. A distance of 0.5 mm between the interproximal margin and the alveolar crest was associated with increased fracture resistance.

CAD/CAM in Phased Maintenance

1991 ◽  
Vol 7 (04) ◽  
pp. 234-247
Author(s):  
Bruce A. Carr ◽  
Thomas M. Houlihan ◽  
Michael A. Polini
Keyword(s):  
Computer Aided Design ◽  
Lead Times ◽  
Reference Information ◽  
Engineering Company ◽  
Network Link ◽  
Engineering Department ◽  
Cad Cam ◽  
One Year ◽  
Aided Design ◽  
Ship Repair

The authors' company is a medium-sized engineering company specializing in naval ship repair. The bulk of corporate work centers on the Phased Maintenance (PM) of three classes of ships. Typically, each PM contract covers three to five different ships per class scheduled for 90-day Availabilities at approximately one-year intervals over a period of five years. The type of work to be performed during each Phased Maintenance Availability (PMA) falls into one of two categories: ship alterations or ship repairs. The first group, ship alterations, is characterized by detailed, long-lead engineering and planning efforts, typically beginning 540 days prior to the vessels's arrival. The second group, ship repairs, makes up the other end of the spectrum with short lead times and compressed service details. The majority of repair items are identified 60 days prior to an Availability, while some are not determined until after the vessel has arrived in the shipyard. The engineering department that services PMA work is composed of three disciplines: structural, mechanical and electrical. The mechanical discipline is further subdivided into the areas of machinery and piping/HVAC. While the nature of PMA work within each discipline is peculiar to the application, the process is similar in each. Reference information is gathered and verified, technical analysis is provided where necessary, and detailed drawings are prepared and submitted for Navy approval prior to shipyard production. All drawings are developed using two-dimensional drafting techniques at various sites by teams of computer-aided design (CAD) input operators utilizing color graphic workstations on a multi-shift basis as required by the workload. Completed drawings are transferred to the engineering site over a network link, where additional workstations are available for engineers to check and correct them as necessary

Review of Marginal Adaptation and Fracture Resistance of Computer Aided Design/Computer Aided Manufacturer (CAD‐CAM) Fabricated Endo-crowns

2021 ◽  
pp. 196-208
Author(s):  
Abdulrahman Alhaddad ◽  
Samar Abuzinadah ◽  
Abdullah Al-Otaibi ◽  
Abrar Alotaibi ◽  
Mohsen Alfkih ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Fracture Resistance ◽  
Systemic Review ◽  
Marginal Adaptation ◽  
Marginal Gap ◽  
Computer Aided ◽  
Cad Cam ◽  
Electronic Database Search ◽  
Cause Of Failure

Background: Zirconia-based restorations have become more popular in dentistry during the last two decades. Patients choose metal-free restorations, preferring materials with similar attributes to natural teeth and similar light scattering characteristics, resulting in a nice esthetic appearance. Restoring a root canal treated teeth is one of the hot topics today. endo crown materials can be either; feldspathic, glass-ceramic, monolithic hybrid ceramic or composite material. Considering the marginal gap of endocrown, an important cause of failure of treatment, the current study evaluated the marginal gap of CAD‐CAM concocted endo-crowns. Materials and Methods: This research is an analysis systemic review study was conducted between January 2020 and October 2021. We followed the PRISMA principles and recorded this systematic review using the PROSPERO database to find and identify published literature related to the marginal adaptation of CAD-CAM-fabricated endocrown. The search will include all relevant articles through the end of 2021. Finally, 24 papers on marginal clearance and fracture resistance in coronary arteries were reviewed. Results: The electronic database search yielded 98 studies that were relevant. After cross-referencing, further seven studies were added. After a full-text analysis and duplicate reduction, 74 of the 98 articles were eliminated. 5 clinical (prospective) studies, 19 in vitro studies were found. Conclusion: This analysis of the recent literature on the marginal seating integrity and fracture resistance of CAD/CAM made-up endo-crowns showed that the endo-crown had superior marginal seating integrity than classical full crown. CAM/CAM showed statistically significant higher mean fracture resistance than MAD/MAM.

scholarly journals Single blinded in-vitro study comparing microleakage between CAD/CAM crowns milled out of feldspathic ceramic and resin nano ceramic, cemented with three resin cements

2019 ◽  
Vol 18 (4) ◽  
pp. 764-772
Author(s):  
Asa Yazdani Fard ◽  
Zuryati Ab Ghani ◽  
Zaihan Ariffin ◽  
Dasmawati Mohamad
Keyword(s):  
Computer Aided Design ◽  
Medical Science ◽  
In Vitro Study ◽  
Resin Cement ◽  
Blue Dye ◽  
Resin Cements ◽  
Etch And Rinse ◽  
Computer Aided ◽  
Cad Cam

Background: Studies on microleakage of Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) crowns are abundant. However many of them are inconclusive, especially those using self adhesive cements. Aims: To compare the microleakage between CAD/CAM crowns milled out of feldspathic ceramic and resin nano ceramics, cemented with three resin cements. Materials and Methods: Crown preparation was made on 54 extracted human premolars. Impressions were captured optically using CEREC 3D machine intraoral camera, and crowns were milled from feldspathic ceramic (CEREC® Blocs PC, VITA) and resin nano ceramic (Lava™ Ultimate CAD/CAM Restorative, 3M ESPE) blocks. The crowns were then cemented with three cements (n = 9); RelyX™ U200 Self-Adhesive Resin Cement (3M ESPE); NX3 Nexus ® cement with two-step etch-and-rinse adhesive (Kerr Corporation) or three/multistep etch-and-rinse resin cement, Variolink® II/Syntac Classic (Ivoclar Vivadent). The specimens were kept in water for 24 hours, thermocycled, and then soaked in methylene blue dye for 24 hours, before being sectioned mesiodistally. Microleakage was assessed using a fivepoint scale using stereomicroscope. Statistical analysis of the data was carried out using ONEWay ANOVA. Results: CEREC® Blocs PC crowns showed significantly less microleakage (p< 0.001) compared to Lava™ Ultimate. RelyX™ U200 showed significantly lower microleakage (p< 0.001) compared to other cements. Combination of Lava™ Ultimate crown cemented with RelyX™ U200 showed the least microleakage (p< 0.001). Conclusions: The microleakage scores were affected by the types of crown and cements. Bangladesh Journal of Medical Science Vol.18(4) 2019 p.764-772

Premolar Axial Wall Height Effect on CAD/CAM Crown Retention

2016 ◽  
Vol 41 (6) ◽  
pp. 666-671 ◽  
Author(s):  
C Gillette ◽  
R Buck ◽  
N DuVall ◽  
S Cushen ◽  
M Wajdowicz ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Failure Resistance ◽  
All Ceramic ◽  
Computer Aided ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Aided Design ◽  
Post Hoc

SUMMARY Objective: To evaluate the significance of reduced axial wall height on retention of adhesively luted, all-ceramic, lithium disilicate premolar computer-aided design/computer-aided manufacturing (CAD/CAM) crowns based on preparations with a near ideal total occlusal convergence of 10°. Methods: Forty-eight recently extracted premolars were randomly divided into four groups (n=12). Each group received all-ceramic CAD/CAM crown preparations featuring axial wall heights of 0, 1, 2, and 3 mm, respectively, all with a 10° total occlusal convergence. Scanned preparations were fitted with lithium disilicate all-ceramic crowns that were luted with a self-etching resin cement. Specimens were tested to failure at a 45° angle to the tooth long axis with failure load converted to megapascals (MPa) based on the measured bonding surface area. Mean data were analyzed using analysis of variance/Tukey's post hoc test (α=0.05). Results: Lithium disilicate crowns adhesively luted on preparations with 0 axial wall height demonstrated significantly less failure resistance compared with the crowns luted on preparations with axial wall heights of 1 to 3 mm. There was no failure stress difference between preparations with 1 to 3 mm axial wall height. Conclusions: Under conditions of this study, adhesively luted lithium disilicate bicuspid crowns with a total occlusal convergence of 10° demonstrated similar failure resistance independent of axial wall height of 1 to 3 mm. This study provides some evidence that adhesion combined with an ideal total occlusal convergence may compensate for reduced axial wall height.

CAD/CAM Endocrown Fabrication from a Polymer-Infiltrated Ceramic Network Block for Primary Molar: A Case Report

2016 ◽  
Vol 40 (4) ◽  
pp. 264-268 ◽  
Author(s):  
Mehmet Selim Bilgin ◽  
Ali Erdem ◽  
Mehmet Tanrıver
Keyword(s):  
Case Report ◽  
Computer Aided Design ◽  
Resin Cement ◽  
Primary Tooth ◽  
Primary Molar ◽  
Long Term Treatment ◽  
Computer Aided ◽  
Cad Cam

Objective: The aim of this case report is to describe the treatment of a primary molar with a deep carious lesion by pulpotomy and placement of a ceramic endocrown. Clinical case: A 7-year-old male patient with profound caries in tooth number 85 was referred to our clinic and underwent a pulpotomy. As the final treatment in tooth restoration, placement of an endocrown was planned, because little more than half of the tooth structure remained. After an additional request from the patient's parents for an advanced and prompt restoration, a computer-aided design/computer-aided manufacturing (CAD/CAM) polymer-infiltrated ceramic network (PICN) block was chosen. A three-dimensional model of the arch was obtained after scanning the dental cast, and the endocrown was designed digitally according to the model. When the design was complete, the endocrown was fabricated with a milling machine. Finally, the endocrown was cemented with self-adhesive resin cement. Results: Over the 9-month follow-up period, no pulpal or periradicular pathology was observed on radiographs. Regarding the crown, the marginal fit was excellent, the anatomical form was protected, and no discoloration occurred. Conclusion: During follow-up, the CAD/CAM PICN block endocrown proved to be a good material for the short- to long-term treatment of a primary tooth. However, more clinical cases and follow-up are required to investigate the long-term effects of antagonistic tooth wear.

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