Surface Roughness and Microhardness of Two Recent CAD/CAM-Materials After Storage

Objectives: To investigate surface roughness and microhardness of two recent resin-ceramic materials for computer-aided design/computer-aided manufacturing (CAD/CAM) after polishing with three polishing systems. Surface roughness and microhardness were measured immediately after polishing and after six months storage including monthly artificial toothbrushing. Methods: Sixty specimens of Lava Ultimate (3M ESPE) and 60 specimens of VITA ENAMIC (VITA Zahnfabrik) were roughened in a standardized manner and polished with one of three polishing systems (n=20/group): Sof-Lex XT discs (SOFLEX; three-step (medium-superfine); 3M ESPE), VITA Polishing Set Clinical (VITA; two-step; VITA Zahnfabrik), or KENDA Unicus (KENDA; one-step; KENDA Dental). Surface roughness (Ra; μm) was measured with a profilometer and microhardness (Vickers; VHN) with a surface hardness indentation device. Ra and VHN were measured immediately after polishing and after six months storage (tap water, 37°C) including monthly artificial toothbrushing (500 cycles/month, toothpaste RDA ~70). Ra- and VHN-values were analysed with nonparametric ANOVA followed by Wilcoxon rank sum tests (α=0.05). Results: For Lava Ultimate, Ra (mean [standard deviation] before/after storage) remained the same when polished with SOFLEX (0.18 [0.09]/0.19 [0.10]; p=0.18), increased significantly with VITA (1.10 [0.44]/1.27 [0.39]; p=0.0001), and decreased significantly with KENDA (0.35 [0.07]/0.33 [0.08]; p=0.03). VHN (mean [standard deviation] before/after storage) decreased significantly regardless of polishing system (SOFLEX: 134.1 [5.6]/116.4 [3.6], VITA: 138.2 [10.5]/115.4 [5.9], KENDA: 135.1 [6.2]/116.7 [6.3]; all p<0.0001). For VITA ENAMIC, Ra (mean [standard deviation] before/after storage) increased significantly when polished with SOFLEX (0.37 [0.18]/0.41 [0.14]; p=0.01) and remained the same with VITA (1.32 [0.37]/1.31 [0.40]; p=0.58) and with KENDA (0.81 [0.35]/0.78 [0.32]; p=0.21). VHN (mean [standard deviation] before/after storage) remained the same regardless of polishing system (SOFLEX: 284.9 [24.6]/282.4 [31.8], VITA: 284.6 [28.5]/276.4 [25.8], KENDA: 292.6 [26.9]/282.9 [24.3]; p=0.42-1.00). Conclusion: Surface roughness and microhardness of Lava Ultimate was more affected by storage and artificial toothbrushing than was VITA ENAMIC.

Dentin Bond Strength of Two Recent CAD/CAM-Materials after Storage

Purpose: To investigate the bond strength to dentin of two recent resin-ceramic materials for computer-aided design/computer-aided manufacturing (CAD/CAM) after 24 hours and after six months storage. Methods and Materials: Ninety cylinders were milled out of Lava Ultimate (3M ESPE) and 90 cylinders out of VITA ENAMIC (VITA Zahnfabrik) (dimension of cylinders: ∅=3.6 mm, h=2 mm). All Lava Ultimate cylinders were sandblasted (aluminium oxide, grain size: 27 μm) and cleaned with ethanol, whereas all VITA ENAMIC cylinders were acid-etched (5% hydrofluoric acid) and cleaned with water-spray. According to the three groups of cements used, the cylinders (n=30/resin-ceramic material) were further pretreated with 1) Scotchbond Universal for RelyX Ultimate (3M ESPE), 2) CLEARFIL Ceramic Primer for PANAVIA F2.0 (Kuraray), or 3) no further pretreatment for Ketac Cem Plus (3M ESPE). The cylinders were then bonded to ground human dentin specimens with 1) Scotchbond Universal and RelyX Ultimate (light-cured), 2) ED PRIMER II and PANAVIA F2.0 (light-cured), or 3) no adhesive system; Ketac Cem Plus (self-cured). Shear bond strength (SBS) was measured after 24 hours for 15 specimens/group and after six months (37°C, 100% humidity) for the other 15 specimens/group. SBS-values were statistically analysed with nonparametric ANOVA followed by exact Wilcoxon rank sum tests (α=0.05). Results: SBS of the two resin-ceramic materials and the three cements after 24 hours and after six months storage are shown in Figure 1. The statistical analysis showed that the duration of storage had a significant effect on SBS of Lava Ultimate for all three cements but had no significant effect on SBS of VITA ENAMIC. For Lava Ultimate SBS-values were (MPa; medians after 24 hours/six months): 13.5/22.5 (p=0.04) for RelyX Ultimate, 11.4/5.8 (p=0.0006) for PANAVIA F2.0, and 0.34/0.09 (p=0.04) for Ketac Cem Plus (Fig. 1). For VITA ENAMIC SBS-values were (MPa; medians after 24 hours/six months): 16.0/21.2 (p=0.10) for RelyX Ultimate, 11.4/14.4 (p=0.06) for PANAVIA F2.0, and 0.43/0.41 (p=0.32) for Ketac Cem Plus (Fig. 1). After 24 hours, there was no significant difference in SBS between Lava Ultimate and VITA ENAMIC for all three cements (p≥0.37). After six months, there was no significant difference in SBS between Lava Ultimate and VITA ENAMIC for RelyX Ultimate and Ketac Cem Plus (p≥0.07) whereas for PANAVIA F2.0, SBS was significantly lower for Lava Ultimate than for VITA ENAMIC (p<0.0001). Conclusion: SBS of Lava Ultimate was more affected by six months storage and by the cement used than was VITA ENAMIC.

CAD/CAM fabrication accuracy of long- vs. short-span implant-supported FDPs

OBJECTIVE To compare the precision of fit of long-span vs. short-span implant-supported screw-retained fixed dental prostheses (FDPs) made from computer-aided-design/computer-aided-manufactured (CAD/CAM) titanium and veneered with ceramic. The null hypothesis was that there is no difference in the vertical microgap between long-span and short-span FDPs. MATERIALS AND METHODS CAD/CAM titanium frameworks for an implant-supported maxillary FDP on implants with a flat platform were fabricated on one single master cast. Group A consisted of six 10-unit FDPs connected to six implants (FDI positions 15, 13, 11, 21, 23, 25) and group B of six 5-unit FDPs (three implants, FDI positions 21, 23, 25). The CAD/CAM system from Biodenta Swiss AG (Berneck, Switzerland) was used for digitizing (laser scanner) the master cast and anatomical CAD of each framework separately. The frameworks were milled (CAM) from a titanium grade V monobloc and veneered with porcelain. Median vertical distance between implant and FDP platforms from the non-tightened implants (one-screw test on implant 25) was calculated from mesial, buccal, and distal scanning electron microscope measurements. RESULTS All measurements showed values <40 μm. Total median vertical microgaps were 23 μm (range 2-38 μm) for group A and 7 μm (4-24 μm) for group B. The difference between the groups was statistically significant at implant 21 (P = 0.002; 97.5% CI -27.3 to -4.9) and insignificant at implant 23 (P = 0.093; -3.9 to 1.0). CONCLUSIONS CAD/CAM fabrication including laboratory scanning and porcelain firing was highly precise and reproducible for all long- and short-span FDPs. While all FDPs showed clinically acceptable values, the short-span FDPs were statistically more precise at the 5-unit span distance.

Dentinhaftkraft zweier neuer CAD/CAM-Materialien in Abhängigkeit verschiedener adhäsiver Zementsysteme

Zielsetzung: Ziel der Studie war die Bestimmung der Dentinhaftkraft von zwei so-genannten Hybridmaterialien für computer-aided design/computer-aided manufacturing (CAD/CAM) Restaurationen unter Anwendung von fünf verschiedenen Zementen vor und nach sechsmonatiger Lagerung. Materialien und Methoden: Aus extrahierten menschlichen Molaren wurden 300 Dentinprobekörper hergestellt (n=15 pro Gruppe; 10 Gruppen (2 Hybridkeramiken, 5 Zemente) je nach 24 h/nach sechsmonatiger Lagerung). Aus Hybridkeramikblöcken von Lava Ultimate (3M ESPE) und VITA ENAMIC (VITA Zahnfabrik) wurden Zylinder hergestellt, welche standardisiert aufgeraut wurden. Anschliessend wurden die Hybrid-keramikzylinder mit einem der folgenden fünf Zemente auf die Dentinprobekörper zementiert: mit den Kompositzementen RelyX Ultimate (3M ESPE), PANAVIA F2.0 (Kuraray), Variolink II (Ivoclar Vivadent), els cem (Saremco Dental AG) oder als Negativkontrollgruppe mit dem kunststoffmodifizierten Glasionomerzement Ketac Cem Plus (3M ESPE). Die Dentinhaftkraft der Hybridkeramikzylinder wurde einerseits nach 24 h und andererseits nach sechsmonatiger Lagerung via Scherkrafttest bestimmt. Nach dem Scherkrafttest wurde das Bruchmuster unter einem Lichtmikroskop bei 40-facher Vergrösserung beurteilt. Die Dentinhaftkraftwerte wurden mittels nichtparametrischer ANOVA gefolgt von exakten Wilcoxon Rangsummen-Tests statistisch analysiert (α=0,05). Die Beurteilung des Bruchmusters wurde deskriptiv ausgewertet. Resultate: Für die Hybridkeramik Lava Ultimate und nach 24 h erzielten die Kompositzemente RelyX Ultimate und Variolink II die höchsten Dentinhaftkraftwerte. Die Dentinhaftkraftwerte von RelyX Ultimate und Variolink II unterschieden sich nicht signifikant. Die Dentinhaftkraftwerte von PANAVIA F2.0 unterschieden sich ebenfalls nicht signifikant von denjenigen von RelyX Ultimate, waren jedoch signifikant tiefer als diejenigen von Variolink II. Unter allen Kompositzementen erzielte els cem die tiefsten Dentinhaftkraftwerte. Nach sechsmonatiger Lagerung waren die Dentinhaftkraftwerte für RelyX Ultimate die höchsten, gefolgt von Variolink II, von els cem und anschliessend von PANAVIA F2.0, welcher nach sechsmonatiger Lagerung die tiefsten Dentinhaftkraftwerte der Kompositzemente zeigte. Der kunststoffmodifizierte Glasionomerzement Ketac Cem Plus zeigte sowohl nach 24 h als auch nach sechsmonatiger Lagerung die tiefsten Dentinhaftkraftwerte. Für VITA ENAMIC war die Reihenfolge der Zemente nach Dentinhaftkraft nach 24 h ähnlich wie diejenige nach sechsmonatiger Lagerung: Die Dentinhaftkraft war für RelyX Ultimate und Variolink II am höchsten, gefolgt von PANAVIA F2.0, von els cem und schlussendlich von Ketac Cem Plus mit den tiefsten Dentinhaftkraftwerten. Nach 24 h und für alle fünf Zemente unterschieden sich die Dentinhaftkraftwerte zwischen Lava Ultimate und VITA ENAMIC nicht signifikant. Nach sechsmonatiger Lagerung unterschieden sich die Dentinhaftkraftwerte zwischen Lava Ultimate und VITA ENAMIC ebenfalls nicht signifikant für RelyX Ultimate und els cem im Gegensatz zu den Dentinhaftkraftwerten von PANAVIA F2.0, Variolink II und Ketac Cem Plus, welche signifikant tiefer waren für Lava Ultimate als für VITA ENAMIC. Das häufigste Bruch-muster war für Lava Ultimate nach 24 h und für VITA ENAMIC sowohl nach 24 h als auch nach sechsmonatiger Lagerung adhäsiv zwischen Dentin und Zement. Nach sechs-monatiger Lagerung war für Lava Ultimate das häufigste Bruchmuster tendenziell gemischte Brüche. Schlussfolgerung: Basierend auf den Resultaten kann gesagt werden, dass für beide Hybridkeramiken sowohl RelyX Ultimate als auch Variolink II empfohlen werden können. PANAVIA F2.0 kann für VITA ENAMIC empfohlen werden, für Lava Ultimate allerdings weniger, da die Dentinhaftkraft nach sechsmonatiger Lagerung abnahm. Von einer konventionellen (allerdings nicht indizierten und in dieser Studie experimentellen) Zemen-tierung der beiden Hybridkeramiken mit dem kunststoffmodifizierten Glasionomerzement Ketac Cem Plus muss abgeraten werden.

Einfluss von Politursystemen auf Oberflächenrauigkeit und mechanische Eigenschaften von CAD/CAM-Materialien

Zielsetzung: Das Ziel dieser Studie war, den Einfluss von drei Politursystemen auf die Oberflächenrauigkeit von verschiedenen Materialien für computer-aided design/computer-aided manufacturing (CAD/CAM) Restaurationen mittels Profilometrie sowie die mikromechanischen Eigenschaften der Materialien mittels Mikrohärtemessgerät zu analysieren. Materialien und Methoden: Von dem CAD/CAM-Kompositmaterial Paradigm MZ100 (3M ESPE), der CAD/CAM-Feldspatkeramik VITABLOCS Mark II (VITA Zahnfabrik) und den CAD/CAM-Hybridmaterialien Lava Ultimate (3M ESPE), VITA ENAMIC (VITA Zahnfabrik) und AMBARINO High-Class (Creamed) wurden je 60 Prüfkörper zugeschnitten, gekennzeichnet und standardisiert aufgerauht. Die standardisierte Aufrauhung wurde mit Baseline-Rauigkeitsmessungen überprüft (Ra und Rz; µm). Die Prüfkörper wurden mit einem von drei Politursystemen poliert (n=20 pro CAD/CAM-Material): 1) Sof-Lex Scheiben (Disc-System, 3 Politurschritte: medium, fein und superfein; 3M ESPE), 2) VITA Polishing Set Clinical (Silikonpolitursystem, 2 Politurschritte: medium und fein; VITA Zahnfabrik) oder 3) KENDA Nobilis (Silikonpolierer, 1 Politurschritt (universal); KENDA Dental). Nach Politur der Prüfkörper wurden Ra und Rz sowie die mikromechanischen Eigenschaften Oberflächenhärte (VHN; Vickers Härte) und Elastizitätsmodul (EM; GPa) gemessen. In den darauf folgenden sechs Monaten wurden die Prüfkörper in Leitungswasser gelagert und insgesamt sechs Mal einem maschinellem Zahnbürsten zugeführt. Anschliessend wurden erneut Ra und Rz sowie VHN und EM gemessen. Ra-, Rz-, VHN- und EM-Werte wurden mittels nichtparametrischer ANOVA global analysiert und die p-Werte mittels Bonferroni-Holm Korrektur für multiples Testen korrigiert. Als post-hoc Tests wurden Kruskal-Wallis-Tests sowie exakte Wilcoxon Rangsummen-Tests verwendet und die p-Werte wurden nicht korrigiert. Das Signifikanzniveau wurde auf α=0,05 festgelegt. Resultate: Für alle drei CAD/CAM-Hybridmaterialien ergaben Sof-Lex Scheiben nach der Politur die tiefste Oberflächenrauigkeit (d. h. die tiefsten Ra- und Rz-Werte), gefolgt von KENDA Nobilis und von dem VITA Polishing Set Clinical. Bei dem CAD/CAM-Kompositmaterial sowie bei der CAD/CAM-Feldspatkeramik ergaben Sof-Lex Scheiben und KENDA Nobilis ähnliche Resultate, gefolgt von dem VITA Polishing Set Clinical. Bei einigen CAD/CAM-Materialien zeigten sich – zum Teil in Abhängigkeit des Politursystems – nach maschinellem Zahnbürsten und Lagerung signifikant höhere Ra- und Rz-Werte. Die CAD/CAM-Materialien zeigten unabhängig des Politursystems und der Lagerung signifikant verschiedene VHN- und EM-Werte. Bei einigen CAD/CAM-Materialien zeigten sich – zum Teil ebenfalls in Abhängigkeit des Politursystems – nach maschinellem Zahn-bürsten und Lagerung signifikant tiefere VHN- und EM-Werte. Schlussfolgerungen: Die Wahl des Politursystems beeinflusste die Oberflächenrauigkeit der CAD/CAM-Materialien markant, wobei Sof-Lex Scheiben insgesamt die besten Politurresultate zeigten, gefolgt von dem Silikonpolierer KENDA Nobilis. Von der Verwendung des Silikonpolitursystems VITA Polishing Set Clinical muss eher abgeraten werden. Das CAD/CAM-Kompositmaterial Paradigm MZ100 und die CAD/CAM-Hybridmaterialien Lava Ultimate und AMBARINO High-Class als weichere und elastischere Materialien liessen sich insgesamt besser polieren, waren aber bezüglich mechanischer Eigenschaften anfälliger auf Lagerung als die härtere CAD/CAM-Feldspatkeramik VITABLOCS Mark II und das CAD/CAM-Hybridmaterial VITA ENAMIC.

Deterministic mathematical morphology for CAD/CAM

Purpose – The purpose of this paper is to present a new geometric model based on the mathematical morphology paradigm, specialized to provide determinism to the classic morphological operations. The determinism is needed to model dynamic processes that require an order of application, as is the case for designing and manufacturing objects in CAD/CAM environments. Design/methodology/approach – The basic trajectory-based operation is the basis of the proposed morphological specialization. This operation allows the definition of morphological operators that obtain sequentially ordered sets of points from the boundary of the target objects, inexistent determinism in the classical morphological paradigm. From this basic operation, the complete set of morphological operators is redefined, incorporating the concept of boundary and determinism: trajectory-based erosion and dilation, and other morphological filtering operations. Findings – This new morphological framework allows the definition of complex three-dimensional objects, providing arithmetical support to generating machining trajectories, one of the most complex problems currently occurring in CAD/CAM. Originality/value – The model proposes the integration of the processes of design and manufacture, so that it avoids the problems of accuracy and integrity that present other classic geometric models that divide these processes in two phases. Furthermore, the morphological operative is based on points sets, so the geometric data structures and the operations are intrinsically simple and efficient. Another important value that no excessive computational resources are needed, because only the points in the boundary are processed.

An effective use of 3-D CAD/CAM withing an overall C.I.M. framework

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Avaliação da adaptação marginal de diferentes tipos de restaurações obtidas por CAD/CAM e métodos convencionais

The past few decades have brought many changes to the dental practice and the technology has become ready available. The result of a satisfactory rehabilitation treatment basically depends on the balance between biological and mechanical factors. The marginal adaptation of crowns and prosthetic structures is vital factor for long-term success. The development of CAD / CAM technology in the manufacture of dental prostheses revolutionized dentistry, this technology is capable of generating a virtual model from the direct digital scanning from the mouth, casts or impressions. It allows the planning and design of the structure in a computered software. The virtual projects are obtained with high precision and a significant reduction in clinical and laboratory time. Thus, the present study (Chapters 1, 2 and 3) computed microtomography was used to evaluate, different materials, different CAD/CAM systems, different ways of obtaining virtual model (with direct or indirect scanning), and in addition, also aims to evaluate the influence of cementing agent in the final adaptation of crowns and copings obtained by CAD / CAM. Furthermore, this study (Chapter 4, 5 and 6) also aims to evaluate significant differences in vertical and horizontal misfits in abutment-free frameworks on external hexagon implants (HE) using full castable UCLAs, castable UCLAs with cobalt-chromium pre-machined bases and obtained by CAD / CAM with CoCr or Zirconia by different scanning and milling systems. For this, the scanning electron microscopy and interferometry were used. It was concluded that the CAD / CAM technology is capable to produce restorations, copings and screw-retained implant-supported frameworks in different materials and systems offering satisfactory results of marginal accuracy, with significative reduction in clinical and laboratory time.

Accuracy of computer-aided design/computer-assisted manufacture (CAD/CAM) fabricated dental restorations: a comparative study

Introduction: Computer-Aided-Design (CAD) and Computer-Aided-Manufacture (CAM) has been developed to fabricate fixed dental restorations accurately, faster and improve cost effectiveness of manufacture when compared to the conventional method. Two main methods exist in dental CAD/CAM technology: the subtractive and additive methods. While fitting accuracy of both methods has been explored, no study yet has compared the fabricated restoration (CAM output) to its CAD in terms of accuracy. The aim of this present study was to compare the output of various dental CAM routes to a sole initial CAD and establish the accuracy of fabrication. The internal fit of the various CAM routes were also investigated. The null hypotheses tested were: 1) no significant differences observed between the CAM output to the CAD and 2) no significant differences observed between the various CAM routes. Methods: An aluminium master model of a standard premolar preparation was scanned with a contact dental scanner (Incise, Renishaw, UK). A single CAD was created on the scanned master model (InciseCAD software, V2.5.0.140, UK). Twenty copings were then fabricated by sending the single CAD to a multitude of CAM routes. The copings were grouped (n=5) as: Laser sintered CoCrMo (LS), 5-axis milled CoCrMo (MCoCrMo), 3-axis milled zirconia (ZAx3) and 4-axis milled zirconia (ZAx4). All copings were micro-CT scanned (Phoenix X-Ray, Nanotom-S, Germany, power: 155kV, current: 60µA, 3600 projections) to produce 3-Dimensional (3D) models. A novel methodology was created to superimpose the micro-CT scans with the CAD (GOM Inspect software, V7.5SR2, Germany) to indicate inaccuracies in manufacturing. The accuracy in terms of coping volume was explored. The distances from the surfaces of the micro-CT 3D models to the surfaces of the CAD model (CAD Deviation) were investigated after creating surface colour deviation maps. Localised digital sections of the deviations (Occlusal, Axial and Cervical) and selected focussed areas were then quantitatively measured using software (GOM Inspect software, Germany). A novel methodology was also explored to digitally align (Rhino software, V5, USA) the micro-CT scans with the master model to investigate internal fit. Fifty digital cross sections of the aligned scans were created. Point-to-point distances were measured at 5 levels at each cross section. The five levels were: Vertical Marginal Fit (VF), Absolute Marginal Fit (AM), Axio-margin Fit (AMF), Axial Fit (AF) and Occlusal Fit (OF). Results: The results of the volume measurement were summarised as: VM-CoCrMo (62.8mm3 ) > VZax3 (59.4mm3 ) > VCAD (57mm3 ) > VZax4 (56.1mm3 ) > VLS (52.5mm3 ) and were all significantly different (p presented as areas with different colour. No significant differences were observed at the internal aspect of the cervical aspect between all groups of copings. Significant differences (p< M-CoCrMo Internal Occlusal, Internal Axial and External Axial 2 ZAx3 > ZAx4 External Occlusal, External Cervical 3 ZAx3 < ZAx4 Internal Occlusal 4 M-CoCrMo > ZAx4 Internal Occlusal and Internal Axial The mean values of AMF and AF were significantly (p M-CoCrMo and CAD > ZAx4. Only VF of M-CoCrMo was comparable with the CAD Internal Fit. All VF and AM values were within the clinically acceptable fit (120µm). Conclusion: The investigated CAM methods reproduced the CAD accurately at the internal cervical aspect of the copings. However, localised deviations at axial and occlusal aspects of the copings may suggest the need for modifications in these areas prior to fitting and veneering with porcelain. The CAM groups evaluated also showed different levels of Internal Fit thus rejecting the null hypotheses. The novel non-destructive methodologies for CAD/CAM accuracy and internal fit testing presented in this thesis may be a useful evaluation tool for similar applications.

Avaliação in vitro da adaptação marginal e interna de coroas de cerâmica e resina composta fabricadas com o sistema CAD/CAM utilizando duas câmeras intraorais de moldagem digital

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ciências da Saúde, Programa de Pós-Graduação em Ciências da Saúde, 2015.

Interfaz AIS para aplicaciones en CAD/CAM/CG

Los modeladores geométricos más comunes en el mercado ofrecen, además de sus servicios de modelado, una API (Application Programming Interface) que permite la construcción de aplicaciones o software cliente -- Estas aplicaciones aprovechan los servicios básicos del modelador para proveer tareas específicas -- Sin embargo las diferencias entre API´s de distintos modeladores imposibilita el intercambio del software cliente entre ellos -- Application Interface Specification -AIS- es una API genérica para ser usada por aplicaciones cliente de los modeladores geométricos -- Este artículo reporta la implementación de AIS sobre AutoCAD® y MicroStation® y discute aspectos importantes de dicha implementación -- Además presenta una aplicación cliente neutra que habla lenguaje AIS y por lo tanto se ejecuta transparentemente sobre los dos modeladores -- AIS se presenta como una alternativa económica para escribir aplicaciones de CAD/CAM/CG -- Futuros desarrollos incluyen la implementación de AIS para labores gráficas y/o de base de datos