Classification systems for all-ceramic materials are useful for communication and educational purposes and warrant continuous revisions and updates to incorporate new materials. This article proposes ...a classification system for ceramic and ceramic-like restorative materials in an attempt to systematize and include a new class of materials. This new classification system categorizes ceramic restorative materials into three families: (1) glass-matrix ceramics, (2) polycrystalline ceramics, and (3) resin-matrix ceramics. Subfamilies are described in each group along with their composition, allowing for newly developed materials to be placed into the already existing main families. The criteria used to differentiate ceramic materials are based on the phase or phases present in their chemical composition. Thus, an all-ceramic material is classified according to whether a glass-matrix phase is present (glass-matrix ceramics) or absent (polycrystalline ceramics) or whether the material contains an organic matrix highly filled with ceramic particles (resin-matrix ceramics). Also presented are the manufacturers' clinical indications for the different materials and an overview of the different fabrication methods and whether they are used as framework materials or monolithic solutions. Current developments in ceramic materials not yet available to the dental market are discussed.
Abstract Objectives To evaluate the effect of framework design modification and veneering techniques in fatigue reliability and failure modes of veneered Yttria-Stabilized Tetragonal Zirconia ...Polycrystals (Y-TZP) crowns. Methods A CAD-based mandibular molar crown preparation served as a master die. Y-TZP crown cores (VITA-In-Ceram-YZ, Vita-Zahnfabrik, Bad Säckingen, Germany) in conventional (0.5 mm uniform thickness) or anatomically designed fashion (cusp support) were porcelain veneered with either hand-layer (VM9) or pressed (PM9) techniques. Crowns ( n = 84) were cemented on 30 days aged dentin-like composite dies with resin cement. Crowns were subjected to single load to fracture ( n = 3 each group) and mouth-motion step-stress fatigue ( n = 18) by sliding a WC indenter ( r = 3.18 mm) 0.7 mm buccally on the inner incline surface of the mesio-lingual cusp. Stress-level curves (use level probability lognormal) and reliability (with 2-sided 90% confidence bounds, CB) for completion of a mission of 50.000 cycles at 200 N load were calculated. Fractographic analyses were performed under light-polarized and scanning electron microscopes. Results Higher reliability for hand-layer veneered conventional core (0.99, CB 0.98-1) was found compared to its counterpart press-veneered (0.50 CB 0.33-65). Framework design modification significantly increased reliability for both veneering techniques (PM9 0.98 CB 0.87-0.99, VM9 1.00 CB 0.99-1) and resulted in reduced veneer porcelain fracture sizes. Main fracture mode observed was veneer porcelain chipping, regardless of framework design and veneering technique. Significance Hand-layer porcelain veneered on conventional core designs presented higher reliability than press-veneered with similar core designs. Anatomic core design modification significantly increased the reliability and resulted in reduced chip size of either veneering techniques.
This JPD Digital video presentation presents the clinical treatment from start to finish in which a dual-shaded bi-coloured monolithic disk was used for the fabrication of an immediate digital ...complete denture followed by the delivery of a definitive digital complete denture. The treatment plan included extraction of the remaining maxillary and mandibular teeth followed by an esthetic evaluation with digital smile design. The digital definitive complete dentures were milled from a monolithic dual-shaded disk.
Abstract Objectives (1) To chemically characterise Y-TZP surface via X-ray photoelectron spectroscopy (XPS) and evaluate the surface energy levels (SE) after non-thermal plasma (NTP). (2) To test the ...microtensile bond strength (MTBS) of Y-TZP bonded to cured composite disks, after a combination of different surface conditioning methods. Methods Twenty-four Y-TZP discs (13.5 mm × 4 mm) were obtained from the manufacturer and composite resin (Z-100) discs with similar dimensions were prepared. All discs were polished to 600 grit and divided into 8 groups ( n = 3 disks each), four control (non-NTP treated) and four experimental (NTP treated for 10 s) groups. All groups received one of the four following treatments prior to cementation with Rely × Unicem cement: sand-blasting (SB), a Clearfil ceramic primer (MDP), sand-blasting + MDP (SBMDP), or baseline (B), no treatment. SE readings and surface roughness parameters were statistically analysed (ANOVA, Tukey's, p < 0.05). Mixed model and paired samples t -tests were used to compare groups on MTBS. Results XPS showed increase in O and decrease in C elements after NTP. The polar component increased for BP (42.20 mN/m) and SBP (43.77 mN/m). MTBS values for groups BP (21.3 MPa), SBP (31 MPa), MDPP (30.1 MPa) and SBMDPP (32.3 MPa) were significantly higher in specimens treated with NTP than their untreated counterparts B (9.1 MPa), SB (14.4 MPa), MDP (17.8 MPa) and SBMDP (24.1 MPa). Conclusions (1) Increase of O and decrease of C led to higher surface energy levels dictated by the polar component after NTP; (2) NTP application increased MTBS values of Y-TZP surfaces.
Abstract Low temperature degradation of zirconia (3Y-TZP) oral implants and its effect on fatigue reliability is poorly documented. Objective The aim of this investigation was to follow the aging ...process occurring at the surface of implants exhibiting a porous coating and to assess its influence on their mechanical (fatigue) properties. Methods Tetragonal to monoclinic transformation (t–m) was evaluated during accelerated aging tests up to 100 h in autoclave (134 °C, 2 bars) by X-ray diffraction (XRD) and focused ion beam (FIB). A series of implants were steam-aged for 20 h before fatigue testing. Such temperature–time conditions would correspond roughly to 40 years in vivo . The aged specimens and a non-aged control group were step-stress fatigued until failure or survival. Results The evolution of XRD surface monoclinic content was slow, i.e. 16% and 35% for 20 and 100 h respectively. However, FIB revealed a significant transformation, initiated at the interface between the porous layer and the bulk, preferentially growing towards the bulk. FIB is therefore better indicated than XRD to follow aging in such implants. Higher average fatigue strength (aged 1235 N versus non-aged 826 N) and reliability levels were observed for the 20 h aged group. Significance After aging for durations compatible with clinical use, 3Y-TZP with porous surface presented higher fatigue performance. This is in contrast to previous studies where loss of strength due to aging was often reported. Generalizations must therefore be avoided when considering aging of zirconia dental products and every new material/process combination should be tested before drawing conclusions.
Esthetic planning with a digital tool: A clinical report Martins, Adriana V., DDS, MSc, PhD; Albuquerque, Rodrigo C., DDS, MSc, PhD; Santos, Telmo R., CDT ...
The Journal of prosthetic dentistry,
12/2017, Letnik:
118, Številka:
6
Journal Article
Recenzirano
Abstract This clinical report describes digital planning and execution using a novel software tool to enhance digital workflow. The proposed treatment, integrated with the face of the patient, was ...presented before clinical treatment. The patient was rehabilitated with ceramic veneers. The virtual design contributed to a satisfactory and predictable esthetic outcome.
The aim of this research was to evaluate the fatigue behavior and reliability of monolithic computer-aided design/computer-assisted manufacture (CAD/CAM) lithium disilicate and hand-layer-veneered ...zirconia all-ceramic crowns.
A CAD-based mandibular molar crown preparation, fabricated using rapid prototyping, served as the master die. Fully anatomically shaped monolithic lithium disilicate crowns (IPS e.max CAD, n = 19) and hand-layer-veneered zirconia-based crowns (IPS e.max ZirCAD/Ceram, n = 21) were designed and milled using a CAD/CAM system. Crowns were cemented on aged dentinlike composite dies with resin cement. Crowns were exposed to mouth-motion fatigue by sliding a WC-indenter (r = 3.18 mm) 0.7 mm lingually down the distobuccal cusp using three different step-stress profiles until failure occurred. Failure was designated as a large chip or fracture through the crown. If no failures occurred at high loads (> 900 N), the test method was changed to staircase r ratio fatigue. Stress level probability curves and reliability were calculated.
Hand-layer-veneered zirconia crowns revealed veneer chipping and had a reliability of < 0.01 (0.03 to 0.00, two-sided 90% confidence bounds) for a mission of 100,000 cycles and a 200-N load. None of the fully anatomically shaped CAD/CAM-fabricated monolithic lithium disilicate crowns failed during step-stress mouth-motion fatigue (180,000 cycles, 900 N). CAD/CAM lithium disilicate crowns also survived r ratio fatigue (1,000,000 cycles, 100 to 1,000 N). There appears to be a threshold for damage/bulk fracture for the lithium disilicate ceramic in the range of 1,100 to 1,200 N.
Based on present fatigue findings, the application of CAD/CAM lithium disilicate ceramic in a monolithic/fully anatomical configuration resulted in fatigue-resistant crowns, whereas hand-layer-veneered zirconia crowns revealed a high susceptibility to mouth-motion cyclic loading with early veneer failures.
Background
Hyperhidrosis (HH) is characterized by exaggerated sweating in a specific region due to hyperfunction of the sweat glands. In the late 2000s, we started treating patients with an ...anticholinergic, oxybutynin, that was not being used until then.
Objectives
To present, after 12 years of utilizing this medication in our service, the substantial experience obtained with the use of oxybutynin as an initial treatment of HH in a large series of 1,658 patients.
Methods
We analyzed 1,658 patients treated with oxybutynin for HH from May 2006 to June 2018. The patients were divided into four groups according to the main site of HH: the plantar group, the axillary group, the facial group, and the palmar group. To measure the degree of satisfaction, a quality of life (QoL) questionnaire was used.
Results
Pre‐treatment QoL was poor or very poor in more than 94% of the cases, and the palmar group had the worst quality of life. After treatment, we observed an improvement in the quality of life in 77% of patients. More than 70% of the patients in all groups present moderate or optimal subjective clinical improvement in sweating after treatment. The group with the best result was the facial group. Intense dry mouth was reported in 24.9% of all patients in all groups.
Conclusions
This study included a large number of patients followed for a long period and demonstrated the good effectiveness of treatment with oxybutynin for hyperhidrosis in the main sites of sweating.
Abstract Objective To compare the fatigue life and damage modes of zirconia crowns fabricated with and without framework design modification when porcelain veneered using a fast or slow cooling ...protocol. Methods Composite resin replicas of a first molar full crown preparation were fabricated. Zirconia copings were milled as conventional (0.5 mm even thickness, Zr-C, n = 20,) or modified (lingual margin of 1.0 mm thickness, 2.0 mm height connected to two proximal struts of 3.5 mm height, Zr-M, n = 20). These groups were subdivided ( n = 10 each) according to the veneer cooling protocol employed: fast cooling (Zr-CFast and Zr-MFast) and slow cooling (Zr-CSlow and Zr-MSlow). Crowns were cemented and fatigued for 106 cycles in water. The number of cycles to failure was recorded and used to determine the interval databased 2-parameter probability Weibull distribution parameter Beta ( β ) and characteristic life value Eta ( η ). Results 2-parameter Weibull calculation presented β = 5.53 and β = 4.38 for Zr-MFast and Zr-CFast, respectively. Slow cooled crowns did not fail by completion of 106 cycles, thereby Weibayes calculation was applied. Increased fatigue life was observed for slow cooled crowns compared to fast cooled ones. Groups Zr-MFast and Zr-MSlow presented no statistical difference. Porcelain cohesive fractures were mainly observed in fast cooled groups. Slow cooled crowns presented in some instances inner cone cracks not reaching the zirconia/veneer interface. Significance Improved fatigue life in tandem with the absence of porcelain fractures were observed in slow cooled crowns, regardless of framework design. Crowns fast cooled chiefly failed by porcelain cohesive fractures.
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