Milton Essig - Academia.edu (original) (raw)
Papers by Milton Essig
Compendium of continuing education in dentistry, 2008
In the past two decades, exciting new developments in dental materials and computer technology ha... more In the past two decades, exciting new developments in dental materials and computer technology have led to the success of contemporary dental computer-aided design/computer-aided manufacture (CAD/CAM) technology. Several highly sophisticated in-office and laboratory CAD/CAM systems have been introduced or are under development. This article provides an overview of the development of various CAD/CAM systems. Operational components, methodologies, and restorative materials used with common CAD/CAM systems are discussed. Research data and clinical studies are presented to substantiate the clinical performance of these systems.
Smile Dental Journal, 2014
Journal of the American Dental Association (1939), 2015
To compare the marginal gap using different types of die stones and titanium dies with and withou... more To compare the marginal gap using different types of die stones and titanium dies with and without powders for imaging. A melamine tooth was prepared and scanned using a laboratory 3-shape scanner to mill a polyurethane die, which was duplicated into different stones (Jade, Lean, CEREC) and titanium. Each die was sprayed with imaging powders (NP, IPS, Optispray, Vita) to form 15 groups. Ten of each combination of stone/titanium and imaging powders were used to mill crowns. A light-bodied impression material was injected into the intaglio surface of each crown and placed on the corresponding die. Each crown was removed, and the monophase material was injected to form a monophase die, which was cut into 8 sections. Digital images were captured using a stereomicroscope to measure marginal gap. Scanning electron microscopy was used to determine the particle size and shape of imaging powders and stones. Marginal gaps ranged from mean (standard deviation) 49.32 to 1.20 micrometers (3.97-4...
Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995), 2005
In the last 2 decades, exciting new developments in dental materials and computer technology have... more In the last 2 decades, exciting new developments in dental materials and computer technology have led to the success of contemporary dental computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Several highly sophisticated chairside and laboratory CAD/CAM systems have been introduced or are under development. This article provides an overview of the development of various CAD/CAM systems. Operational components, methodologies, and restorative materials used with common CAD/CAM systems are discussed. Research data and clinical studies are presented to substantiate the clinical performance of these systems.
Journal of the American Dental Association (1939), 1989
The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and mill... more The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and milling ceramic restorations. The system makes it possible to generate a restoration without taking impressions, developing temporary prostheses, and without laboratory assistance. The entire restorative procedure is performed in one appointment. Basic features include the following: the cavity preparation is scanned stereo-photogrammetrically, using a three-dimensional miniature video camera; the small microprocessor unit stores the three-dimensional pattern depicted on the screen; the video display serves as a format for the necessary manual construction via an electrical signal; the microprocessor develops the final three-dimensional restoration from the two-dimensional construction; the processing unit automatically deletes data beyond the margins of the preparation; the electronic information is transferred numerically to the miniature three-axis milling device; driven by a water turbin...
Journal of Prosthodontics, 2012
The effect of dental fabrication procedures of zirconia monolithic restorations and changes in pr... more The effect of dental fabrication procedures of zirconia monolithic restorations and changes in properties during low-temperature exposure in the oral environment is not completely understood. The purpose of this study was to investigate the effect of procedures for fabrication of dental restorations by low-temperature simulation and relative changes of flexural strength, nanoindentation hardness, Young's modulus, surface roughness, and structural stability of yttria-stabilized zirconia. Materials and Methods: A total of 64 zirconia specimens were prepared to simulate dental practice. The specimens were divided into the control group and the accelerated aging group. The simulated group followed the same procedure as the control group except for the aging treatment. Atomic force microscopy was used to measure surface roughness. The degree of tetragonal-to-monoclinic transformation was determined using X-ray diffraction. Nanoindentation hardness and modulus measurements were carried out on the surface of the zirconia specimens using a nanoindenter XP/G200 system. The yttria levels for nonaged and aged specimens were measured using energy dispersive spectroscopy. Flexural strength was determined using the piston-on-threeball test. The t-test was used to determine statistical significance. Results: Means and standard deviations were calculated using all observations for each condition and evaluated using a group t-test (p < 0.05). The LTD treatment resulted in increased surface roughness (from 12.23 nm to 21.56 nm for Ra and 15.06 nm to 27.45 nm for RMS) and monoclinic phase fractions (from 2% to 21%), with a concomitant decrease in hardness (from 16.56 GPa to 15.14 GPa) and modulus (from 275.68 GPa to 256.56 GPa). Yttria content (from 4.43% to 4.46%) and flexural strength (from 586 MPa to 578 MPa) were not significantly altered, supporting longer term in vivo function without biomechanical fracture. Conclusion: The LTD treatment induced the tetragonal-to-monoclinic transformation with surface roughening in zirconia prepared using dental procedures.
The Journal of Prosthetic Dentistry, 2012
The importance of trial insertion paste color is a function of veneer material, with IPS e.max CA... more The importance of trial insertion paste color is a function of veneer material, with IPS e.max CAD veneers being more sensitive than feldspathic porcelain. Selecting the luting cement color before cementation is important in achieving the desired esthetics for IPS e.max CAD HT veneers and is of some importance for feldspathic porcelain veneers. Luting cement color or substrate color had no effect on the observed shade of yttria-stabilized zirconia laminate veneers. The bond quality of zirconia veneers to the tooth is uncertain, and their long-term adhesion has not been clinically proven.
The Journal of Prosthetic Dentistry, 2012
Zirconia veneers demonstrated, in vitro, the ability to withstand higher load before fracture tha... more Zirconia veneers demonstrated, in vitro, the ability to withstand higher load before fracture than glass-ceramic and feldspathic porcelain laminate veneers, which supports expanded clinical applications. Statement of problem. Fracture of feldspathic porcelain laminate veneers represents a significant mode of clinical failure. Therefore, ceramic materials that withstand a higher load to fracture, especially for patients with parafunctional habits, are needed.
Journal of Esthetic and Restorative Dentistry, 1992
This study dealt with the clinical evaluation of 121 inlays and onlays generated from both Dicor ... more This study dealt with the clinical evaluation of 121 inlays and onlays generated from both Dicor ceramics and Vita porcelains. These two different types of ceramic materials were cemented using three different duo-cured composite resin luting agents, which differed in particle size. At the end of 3 years, no difference could be detected between the clinical performance of the Dicor and Vita restorations. Both exhibited the same degree of color matching characteristics, marginal integrity, and general clinical performance; however, seven of the restorations exhibited fracture through the isthmus, which was shown to be due to insufficient cavity depth. The balance of the restorations exhibited excellent clinical performance when evaluated against the United States Public Health Service System.
Journal of dentistry, 2012
The purpose of this investigation is to evaluate marginal discrepancy and fracture resistance of ... more The purpose of this investigation is to evaluate marginal discrepancy and fracture resistance of two veneering materials using two preparation designs.
Journal of prosthodontics : official journal of the American College of Prosthodontists, 2012
Purpose: Marginal adaptation is an important factor affecting the longevity of all-ceramic restor... more Purpose: Marginal adaptation is an important factor affecting the longevity of all-ceramic restorations, although the effects of different fabrication steps on marginal adaptation at various stages of fabrication are not fully understood. The purpose of this study was to assess with an in vitro model whether In-Ceram alumina (IA) or In-Ceram zirconia (IZ) copings produced by the CAD/CAM method would be clinically acceptable, and to evaluate the effect of each fabrication step (post-milling, post-trimming, and post-glass infiltration) on the marginal discrepancy of the coping. Materials and Methods: A melamine tooth was prepared, duplicated, poured with inlay wax, and then cast with metal to fabricate a master die. An InLab 3D system was used to scan the master die and to design and mill the copings. Thirty IA and IZ copings each were developed with thicknesses of 0.6 mm and a 30-μm thick computer luting space. Epoxy resin replicas of the master die were fabricated, and the vertical ...
Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995), 2005
In the last 2 decades, exciting new developments in dental materials and computer technology have... more In the last 2 decades, exciting new developments in dental materials and computer technology have led to the success of contemporary dental computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Several highly sophisticated chairside and laboratory CAD/CAM systems have been introduced or are under development. This article provides an overview of the development of various CAD/CAM systems. Operational components, methodologies, and restorative materials used with common CAD/CAM systems are discussed. Research data and clinical studies are presented to substantiate the clinical performance of these systems.
Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.], Jan 11, 2015
This clinical report describes an alternative treatment modality for the replacement of congenita... more This clinical report describes an alternative treatment modality for the replacement of congenitally missing maxillary lateral incisors in a 17-year-old patient. Zirconia-based resin-bonded fixed partial dentures (RBFPDs) were selected as a viable and conservative treatment option in a young individual with highly aesthetic expectations. Fabrication of all-ceramic RBFPDs followed specific preparation design and features to accommodate two retainers. The zirconia frameworks with bilateral wings were digitally designed and then milled by a computer-aided design and computer-aided manufacturing (CAD/CAM)-controlled milling machine. Zirconia surface was treated with a two-step chairside tribochemical silica-coating/silane coupling surface treatment protocol, and adhesive resin luting cement was used to achieve micromechanical and chemical bonding. Completion of the treatment resulted in a functional and aesthetic successful outcome and a 17-month follow-up presented uneventful. Contempo...
Objectives: To investigate the effects of try-in paste (TP) color, composite resin abutment (CRA)... more Objectives: To investigate the effects of try-in paste (TP) color, composite resin abutment (CRA) color, and ceramic thickness on color changes of feldspathic porcelain (FP), yttria-stabilized zirconia (Y-TZP) and IPS e.maxCAD (IEC) laminate veneers. Methods: A melamine tooth was prepared for laminate veneering. A master die was fabricated from a tooth impression which was scanned and designed using TurboDent system. Ten CRA of each color (A1, A2, A3) were machined from resin blocks. Ten veneers were fabricated for each veneer material. The thicknesses were measured at each specific region (cervical, body, incisal). Color coordinates were determined at each region with different colors of CRA and TP (transparent, bleach XL, opaque, yellow) using a spectrophotometer. A color difference (ΔE) of 3.7 was considered the perceptibility threshold. Results: The data for ΔE of all veneers with different TP, and CRA colors at each region are shown in Figure 1(a,b,c). FP and IEC veneers were a...
Journal of the American Dental Association (1939), 2015
To compare the marginal gap using different types of die stones and titanium dies with and withou... more To compare the marginal gap using different types of die stones and titanium dies with and without powders for imaging. A melamine tooth was prepared and scanned using a laboratory 3-shape scanner to mill a polyurethane die, which was duplicated into different stones (Jade, Lean, CEREC) and titanium. Each die was sprayed with imaging powders (NP, IPS, Optispray, Vita) to form 15 groups. Ten of each combination of stone/titanium and imaging powders were used to mill crowns. A light-bodied impression material was injected into the intaglio surface of each crown and placed on the corresponding die. Each crown was removed, and the monophase material was injected to form a monophase die, which was cut into 8 sections. Digital images were captured using a stereomicroscope to measure marginal gap. Scanning electron microscopy was used to determine the particle size and shape of imaging powders and stones. Marginal gaps ranged from mean (standard deviation) 49.32 to 1.20 micrometers (3.97-4...
Journal of the American Dental Association (1939), 1989
The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and mill... more The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and milling ceramic restorations. The system makes it possible to generate a restoration without taking impressions, developing temporary prostheses, and without laboratory assistance. The entire restorative procedure is performed in one appointment. Basic features include the following: the cavity preparation is scanned stereo-photogrammetrically, using a three-dimensional miniature video camera; the small microprocessor unit stores the three-dimensional pattern depicted on the screen; the video display serves as a format for the necessary manual construction via an electrical signal; the microprocessor develops the final three-dimensional restoration from the two-dimensional construction; the processing unit automatically deletes data beyond the margins of the preparation; the electronic information is transferred numerically to the miniature three-axis milling device; driven by a water turbin...
ABSTRACT Objectives: The purpose of this study is to investigate the influence of low-temperature... more ABSTRACT Objectives: The purpose of this study is to investigate the influence of low-temperature degradation (LTD) treatment on the nanoindentation hardness, surface roughness, and structural stability of yttria-stabilized zirconia. Methods: Eight zirconia samples were manufactured using the exact dental laboratory procedure used to fabricate zirconia restorations. The samples were finished, colored, sintered, ground, and polished and then were given the firing used to apply porcelain but without application of the veneering material. The samples were divided into the control group and the accelerated aging group. The accelerated group followed the same procedure as the control group except for the aging treatment (100 C, 7 days in boiling artificial saliva) in order to simulate LTD in the oral environment. Atomic force microscopy (AFM) was used to measure surface roughness. The degree of tetragonal-to-monoclinic transformation was determined using x-ray diffractometer. Nanoindentation and Young's modulus measurements were carried out on the surface of the zirconia samples using a nanoindenter XP/G200 system. The yttria level for non-aged and aged samples was measured using SEM/EDS. Results: Quantitative results are shown in Table 1. Means and standard deviations were calculated using all observations for each condition. The p value comparing non-aged and aged values comes from a group t test. The LTD treatment results in increased surface roughness and monoclinic phase fractions, with a concomitant decrease in hardness and modulus. Stabilizer content was unchanged. Conclusion: The LTD treatment induced the tetragonal-to-monoclinic transformation in zirconia prepared using dental fabrication practices. Table 1. Preliminary results for aged and non-aged zirconia samples Number of testing spots per sample Value SD (non-aged samples) Value SD (aged samples) p-value Surface Roughness Ra (nm) 16 12.236.16 21.5613.39 0.017 RMS (nm) 16 15.067.23 27.4516.16 0.009 Amount of Monoclinic (%) 2.40.6 21.02.0 <0.001 Hardness (GPa) 97 16.560.81 15.141.83 <0.001 Young's Modulus (GPa) 97 275.6812.26 256.5621.56 <0.001 Elemental Analysis (wt %) Zr 12 80.733.18 80.682.51 0.966 O 12 11.413.50 11.452.47 0.974 Y 12 4.430.32 4.460.43 0.848 Hf 12 3.090.27 3.130.31 0.739 Al 12 0.3050.158 0.3050.239 0.999
Journal of Prosthodontics, 2012
The effect of dental fabrication procedures of zirconia monolithic restorations and changes in pr... more The effect of dental fabrication procedures of zirconia monolithic restorations and changes in properties during low-temperature exposure in the oral environment is not completely understood. The purpose of this study was to investigate the effect of procedures for fabrication of dental restorations by low-temperature simulation and relative changes of flexural strength, nanoindentation hardness, Young&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s modulus, surface roughness, and structural stability of yttria-stabilized zirconia. A total of 64 zirconia specimens were prepared to simulate dental practice. The specimens were divided into the control group and the accelerated aging group. The simulated group followed the same procedure as the control group except for the aging treatment. Atomic force microscopy was used to measure surface roughness. The degree of tetragonal-to-monoclinic transformation was determined using X-ray diffraction. Nanoindentation hardness and modulus measurements were carried out on the surface of the zirconia specimens using a nanoindenter XP/G200 system. The yttria levels for nonaged and aged specimens were measured using energy dispersive spectroscopy. Flexural strength was determined using the piston-on-three-ball test. The t-test was used to determine statistical significance. Means and standard deviations were calculated using all observations for each condition and evaluated using a group t-test (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The LTD treatment resulted in increased surface roughness (from 12.23 nm to 21.56 nm for Ra and 15.06 nm to 27.45 nm for RMS) and monoclinic phase fractions (from 2% to 21%), with a concomitant decrease in hardness (from 16.56 GPa to 15.14 GPa) and modulus (from 275.68 GPa to 256.56 GPa). Yttria content (from 4.43% to 4.46%) and flexural strength (from 586 MPa to 578 MPa) were not significantly altered, supporting longer term in vivo function without biomechanical fracture. The LTD treatment induced the tetragonal-to-monoclinic transformation with surface roughening in zirconia prepared using dental procedures.
The Journal of Prosthetic Dentistry, 2012
When feldspathic porcelain (FP) laminate veneers are used to mask tooth discoloration that extend... more When feldspathic porcelain (FP) laminate veneers are used to mask tooth discoloration that extends into the dentin, significant tooth reduction is needed to provide space for the opaque layer and optimize the bonding of the restoration. The purpose of this study was to investigate the color effect of trial insertion paste (TP), composite resin abutment (CRA), and veneer regions on the optical properties of feldspathic porcelain (FP), yttria-stabilized zirconia (Y-TZP), and IPS e.max CAD HT (IEC) veneers. A melamine tooth was prepared for a laminate veneer on a model, and a definitive cast was made. The definitive die was scanned by using the TurboDent System (TDS), then 30 CRA were machined and 10 veneers were fabricated for each ceramic material (FP, Y-TZP, IEC). The optical properties of different veneer materials, CRA (A(1), A(2), A(3)) and TP (bleach XL, opaque white, transparent, and yellow) were evaluated in the cervical, body, and incisal regions with a spectrophotometer. Results were analyzed by using 1-way ANOVA (.05). The color difference for all the veneers was affected by TP and CRA colors in different regions. The mean values for the Y-TZP veneer color coordinates (L*: 74 ±0.34, a*: 0.09 ±0.20, and b*: 17.43 ±0.44) were significantly different (P&amp;amp;amp;amp;amp;amp;amp;lt;.001) from those of IEC veneers (L*: 70.15 ±0.23, a*: -0.69 ±0.073, and b*:11.48 ±0.30) and FP veneers (L*: 70.00 ±0.86, a*: - 0.28 ±0.203, and b*: 13.86 ±1.08). There was no difference between IEC for L* and FP. Significant difference was detected (P&amp;amp;amp;amp;amp;amp;amp;lt;.001) in color coordinates among the 3 veneer materials for a* and b*. The TP color affected the color difference for all veneer materials except the Y-TZP, while there was no effect on the CRA color. The magnitude of color coordinates changed as a function of TP color and veneer material.
The Journal of Prosthetic Dentistry, 2012
Fracture of feldspathic porcelain laminate veneers represents a significant mode of clinical fail... more Fracture of feldspathic porcelain laminate veneers represents a significant mode of clinical failure. Therefore, ceramic materials that withstand a higher load to fracture, especially for patients with parafunctional habits, are needed. The purpose of this study was to examine the correlation of material (zirconia, TZP, glass-ceramic, IEC, and feldspathic porcelain, FP) design (incisal overlapped preparation, IOP, and three-quarter preparation, TQP), and fracture mode to failure load for veneers supported by composite resin abutments. A typodont tooth prepared with 2 designs (IOP, TQP) and the corresponding 2 definitive dies were used to fabricate the composite resin abutments (30 for IOP and 30 for TQP). Ten veneer specimens for each system (Y-TZP, IEC, and FP), were fabricated for each design. The veneers were cemented, invested, and tested in compression until failure by using a universal testing machine. Significant differences were evaluated by 2-factor ANOVA (α=.05). No statistical mean load difference was noted between the preparation designs for Y-TZP (IOP: 244 ±81 and TQP: 224 ±58 N), IEC (IOP: 306 ±101 and TQP: 263 ±77 N), and FP veneers (IOP: 161 ±93 and TQP: 246 ±45 N). No statistical difference in the mean load was found among the 3 veneer materials for each preparation design except between IEC (306 ±101 N) and FP (161 ±93 N) veneers for TQP. Preparation design did not influence the failure load of the veneer materials. Zirconia veneers were the least likely to fracture but the most likely to completely debond; feldspathic porcelain veneers exhibited the opposite characteristics.
Compendium of continuing education in dentistry, 2008
In the past two decades, exciting new developments in dental materials and computer technology ha... more In the past two decades, exciting new developments in dental materials and computer technology have led to the success of contemporary dental computer-aided design/computer-aided manufacture (CAD/CAM) technology. Several highly sophisticated in-office and laboratory CAD/CAM systems have been introduced or are under development. This article provides an overview of the development of various CAD/CAM systems. Operational components, methodologies, and restorative materials used with common CAD/CAM systems are discussed. Research data and clinical studies are presented to substantiate the clinical performance of these systems.
Smile Dental Journal, 2014
Journal of the American Dental Association (1939), 2015
To compare the marginal gap using different types of die stones and titanium dies with and withou... more To compare the marginal gap using different types of die stones and titanium dies with and without powders for imaging. A melamine tooth was prepared and scanned using a laboratory 3-shape scanner to mill a polyurethane die, which was duplicated into different stones (Jade, Lean, CEREC) and titanium. Each die was sprayed with imaging powders (NP, IPS, Optispray, Vita) to form 15 groups. Ten of each combination of stone/titanium and imaging powders were used to mill crowns. A light-bodied impression material was injected into the intaglio surface of each crown and placed on the corresponding die. Each crown was removed, and the monophase material was injected to form a monophase die, which was cut into 8 sections. Digital images were captured using a stereomicroscope to measure marginal gap. Scanning electron microscopy was used to determine the particle size and shape of imaging powders and stones. Marginal gaps ranged from mean (standard deviation) 49.32 to 1.20 micrometers (3.97-4...
Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995), 2005
In the last 2 decades, exciting new developments in dental materials and computer technology have... more In the last 2 decades, exciting new developments in dental materials and computer technology have led to the success of contemporary dental computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Several highly sophisticated chairside and laboratory CAD/CAM systems have been introduced or are under development. This article provides an overview of the development of various CAD/CAM systems. Operational components, methodologies, and restorative materials used with common CAD/CAM systems are discussed. Research data and clinical studies are presented to substantiate the clinical performance of these systems.
Journal of the American Dental Association (1939), 1989
The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and mill... more The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and milling ceramic restorations. The system makes it possible to generate a restoration without taking impressions, developing temporary prostheses, and without laboratory assistance. The entire restorative procedure is performed in one appointment. Basic features include the following: the cavity preparation is scanned stereo-photogrammetrically, using a three-dimensional miniature video camera; the small microprocessor unit stores the three-dimensional pattern depicted on the screen; the video display serves as a format for the necessary manual construction via an electrical signal; the microprocessor develops the final three-dimensional restoration from the two-dimensional construction; the processing unit automatically deletes data beyond the margins of the preparation; the electronic information is transferred numerically to the miniature three-axis milling device; driven by a water turbin...
Journal of Prosthodontics, 2012
The effect of dental fabrication procedures of zirconia monolithic restorations and changes in pr... more The effect of dental fabrication procedures of zirconia monolithic restorations and changes in properties during low-temperature exposure in the oral environment is not completely understood. The purpose of this study was to investigate the effect of procedures for fabrication of dental restorations by low-temperature simulation and relative changes of flexural strength, nanoindentation hardness, Young's modulus, surface roughness, and structural stability of yttria-stabilized zirconia. Materials and Methods: A total of 64 zirconia specimens were prepared to simulate dental practice. The specimens were divided into the control group and the accelerated aging group. The simulated group followed the same procedure as the control group except for the aging treatment. Atomic force microscopy was used to measure surface roughness. The degree of tetragonal-to-monoclinic transformation was determined using X-ray diffraction. Nanoindentation hardness and modulus measurements were carried out on the surface of the zirconia specimens using a nanoindenter XP/G200 system. The yttria levels for nonaged and aged specimens were measured using energy dispersive spectroscopy. Flexural strength was determined using the piston-on-threeball test. The t-test was used to determine statistical significance. Results: Means and standard deviations were calculated using all observations for each condition and evaluated using a group t-test (p < 0.05). The LTD treatment resulted in increased surface roughness (from 12.23 nm to 21.56 nm for Ra and 15.06 nm to 27.45 nm for RMS) and monoclinic phase fractions (from 2% to 21%), with a concomitant decrease in hardness (from 16.56 GPa to 15.14 GPa) and modulus (from 275.68 GPa to 256.56 GPa). Yttria content (from 4.43% to 4.46%) and flexural strength (from 586 MPa to 578 MPa) were not significantly altered, supporting longer term in vivo function without biomechanical fracture. Conclusion: The LTD treatment induced the tetragonal-to-monoclinic transformation with surface roughening in zirconia prepared using dental procedures.
The Journal of Prosthetic Dentistry, 2012
The importance of trial insertion paste color is a function of veneer material, with IPS e.max CA... more The importance of trial insertion paste color is a function of veneer material, with IPS e.max CAD veneers being more sensitive than feldspathic porcelain. Selecting the luting cement color before cementation is important in achieving the desired esthetics for IPS e.max CAD HT veneers and is of some importance for feldspathic porcelain veneers. Luting cement color or substrate color had no effect on the observed shade of yttria-stabilized zirconia laminate veneers. The bond quality of zirconia veneers to the tooth is uncertain, and their long-term adhesion has not been clinically proven.
The Journal of Prosthetic Dentistry, 2012
Zirconia veneers demonstrated, in vitro, the ability to withstand higher load before fracture tha... more Zirconia veneers demonstrated, in vitro, the ability to withstand higher load before fracture than glass-ceramic and feldspathic porcelain laminate veneers, which supports expanded clinical applications. Statement of problem. Fracture of feldspathic porcelain laminate veneers represents a significant mode of clinical failure. Therefore, ceramic materials that withstand a higher load to fracture, especially for patients with parafunctional habits, are needed.
Journal of Esthetic and Restorative Dentistry, 1992
This study dealt with the clinical evaluation of 121 inlays and onlays generated from both Dicor ... more This study dealt with the clinical evaluation of 121 inlays and onlays generated from both Dicor ceramics and Vita porcelains. These two different types of ceramic materials were cemented using three different duo-cured composite resin luting agents, which differed in particle size. At the end of 3 years, no difference could be detected between the clinical performance of the Dicor and Vita restorations. Both exhibited the same degree of color matching characteristics, marginal integrity, and general clinical performance; however, seven of the restorations exhibited fracture through the isthmus, which was shown to be due to insufficient cavity depth. The balance of the restorations exhibited excellent clinical performance when evaluated against the United States Public Health Service System.
Journal of dentistry, 2012
The purpose of this investigation is to evaluate marginal discrepancy and fracture resistance of ... more The purpose of this investigation is to evaluate marginal discrepancy and fracture resistance of two veneering materials using two preparation designs.
Journal of prosthodontics : official journal of the American College of Prosthodontists, 2012
Purpose: Marginal adaptation is an important factor affecting the longevity of all-ceramic restor... more Purpose: Marginal adaptation is an important factor affecting the longevity of all-ceramic restorations, although the effects of different fabrication steps on marginal adaptation at various stages of fabrication are not fully understood. The purpose of this study was to assess with an in vitro model whether In-Ceram alumina (IA) or In-Ceram zirconia (IZ) copings produced by the CAD/CAM method would be clinically acceptable, and to evaluate the effect of each fabrication step (post-milling, post-trimming, and post-glass infiltration) on the marginal discrepancy of the coping. Materials and Methods: A melamine tooth was prepared, duplicated, poured with inlay wax, and then cast with metal to fabricate a master die. An InLab 3D system was used to scan the master die and to design and mill the copings. Thirty IA and IZ copings each were developed with thicknesses of 0.6 mm and a 30-μm thick computer luting space. Epoxy resin replicas of the master die were fabricated, and the vertical ...
Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995), 2005
In the last 2 decades, exciting new developments in dental materials and computer technology have... more In the last 2 decades, exciting new developments in dental materials and computer technology have led to the success of contemporary dental computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Several highly sophisticated chairside and laboratory CAD/CAM systems have been introduced or are under development. This article provides an overview of the development of various CAD/CAM systems. Operational components, methodologies, and restorative materials used with common CAD/CAM systems are discussed. Research data and clinical studies are presented to substantiate the clinical performance of these systems.
Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.], Jan 11, 2015
This clinical report describes an alternative treatment modality for the replacement of congenita... more This clinical report describes an alternative treatment modality for the replacement of congenitally missing maxillary lateral incisors in a 17-year-old patient. Zirconia-based resin-bonded fixed partial dentures (RBFPDs) were selected as a viable and conservative treatment option in a young individual with highly aesthetic expectations. Fabrication of all-ceramic RBFPDs followed specific preparation design and features to accommodate two retainers. The zirconia frameworks with bilateral wings were digitally designed and then milled by a computer-aided design and computer-aided manufacturing (CAD/CAM)-controlled milling machine. Zirconia surface was treated with a two-step chairside tribochemical silica-coating/silane coupling surface treatment protocol, and adhesive resin luting cement was used to achieve micromechanical and chemical bonding. Completion of the treatment resulted in a functional and aesthetic successful outcome and a 17-month follow-up presented uneventful. Contempo...
Objectives: To investigate the effects of try-in paste (TP) color, composite resin abutment (CRA)... more Objectives: To investigate the effects of try-in paste (TP) color, composite resin abutment (CRA) color, and ceramic thickness on color changes of feldspathic porcelain (FP), yttria-stabilized zirconia (Y-TZP) and IPS e.maxCAD (IEC) laminate veneers. Methods: A melamine tooth was prepared for laminate veneering. A master die was fabricated from a tooth impression which was scanned and designed using TurboDent system. Ten CRA of each color (A1, A2, A3) were machined from resin blocks. Ten veneers were fabricated for each veneer material. The thicknesses were measured at each specific region (cervical, body, incisal). Color coordinates were determined at each region with different colors of CRA and TP (transparent, bleach XL, opaque, yellow) using a spectrophotometer. A color difference (ΔE) of 3.7 was considered the perceptibility threshold. Results: The data for ΔE of all veneers with different TP, and CRA colors at each region are shown in Figure 1(a,b,c). FP and IEC veneers were a...
Journal of the American Dental Association (1939), 2015
To compare the marginal gap using different types of die stones and titanium dies with and withou... more To compare the marginal gap using different types of die stones and titanium dies with and without powders for imaging. A melamine tooth was prepared and scanned using a laboratory 3-shape scanner to mill a polyurethane die, which was duplicated into different stones (Jade, Lean, CEREC) and titanium. Each die was sprayed with imaging powders (NP, IPS, Optispray, Vita) to form 15 groups. Ten of each combination of stone/titanium and imaging powders were used to mill crowns. A light-bodied impression material was injected into the intaglio surface of each crown and placed on the corresponding die. Each crown was removed, and the monophase material was injected to form a monophase die, which was cut into 8 sections. Digital images were captured using a stereomicroscope to measure marginal gap. Scanning electron microscopy was used to determine the particle size and shape of imaging powders and stones. Marginal gaps ranged from mean (standard deviation) 49.32 to 1.20 micrometers (3.97-4...
Journal of the American Dental Association (1939), 1989
The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and mill... more The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and milling ceramic restorations. The system makes it possible to generate a restoration without taking impressions, developing temporary prostheses, and without laboratory assistance. The entire restorative procedure is performed in one appointment. Basic features include the following: the cavity preparation is scanned stereo-photogrammetrically, using a three-dimensional miniature video camera; the small microprocessor unit stores the three-dimensional pattern depicted on the screen; the video display serves as a format for the necessary manual construction via an electrical signal; the microprocessor develops the final three-dimensional restoration from the two-dimensional construction; the processing unit automatically deletes data beyond the margins of the preparation; the electronic information is transferred numerically to the miniature three-axis milling device; driven by a water turbin...
ABSTRACT Objectives: The purpose of this study is to investigate the influence of low-temperature... more ABSTRACT Objectives: The purpose of this study is to investigate the influence of low-temperature degradation (LTD) treatment on the nanoindentation hardness, surface roughness, and structural stability of yttria-stabilized zirconia. Methods: Eight zirconia samples were manufactured using the exact dental laboratory procedure used to fabricate zirconia restorations. The samples were finished, colored, sintered, ground, and polished and then were given the firing used to apply porcelain but without application of the veneering material. The samples were divided into the control group and the accelerated aging group. The accelerated group followed the same procedure as the control group except for the aging treatment (100 C, 7 days in boiling artificial saliva) in order to simulate LTD in the oral environment. Atomic force microscopy (AFM) was used to measure surface roughness. The degree of tetragonal-to-monoclinic transformation was determined using x-ray diffractometer. Nanoindentation and Young's modulus measurements were carried out on the surface of the zirconia samples using a nanoindenter XP/G200 system. The yttria level for non-aged and aged samples was measured using SEM/EDS. Results: Quantitative results are shown in Table 1. Means and standard deviations were calculated using all observations for each condition. The p value comparing non-aged and aged values comes from a group t test. The LTD treatment results in increased surface roughness and monoclinic phase fractions, with a concomitant decrease in hardness and modulus. Stabilizer content was unchanged. Conclusion: The LTD treatment induced the tetragonal-to-monoclinic transformation in zirconia prepared using dental fabrication practices. Table 1. Preliminary results for aged and non-aged zirconia samples Number of testing spots per sample Value SD (non-aged samples) Value SD (aged samples) p-value Surface Roughness Ra (nm) 16 12.236.16 21.5613.39 0.017 RMS (nm) 16 15.067.23 27.4516.16 0.009 Amount of Monoclinic (%) 2.40.6 21.02.0 <0.001 Hardness (GPa) 97 16.560.81 15.141.83 <0.001 Young's Modulus (GPa) 97 275.6812.26 256.5621.56 <0.001 Elemental Analysis (wt %) Zr 12 80.733.18 80.682.51 0.966 O 12 11.413.50 11.452.47 0.974 Y 12 4.430.32 4.460.43 0.848 Hf 12 3.090.27 3.130.31 0.739 Al 12 0.3050.158 0.3050.239 0.999
Journal of Prosthodontics, 2012
The effect of dental fabrication procedures of zirconia monolithic restorations and changes in pr... more The effect of dental fabrication procedures of zirconia monolithic restorations and changes in properties during low-temperature exposure in the oral environment is not completely understood. The purpose of this study was to investigate the effect of procedures for fabrication of dental restorations by low-temperature simulation and relative changes of flexural strength, nanoindentation hardness, Young&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s modulus, surface roughness, and structural stability of yttria-stabilized zirconia. A total of 64 zirconia specimens were prepared to simulate dental practice. The specimens were divided into the control group and the accelerated aging group. The simulated group followed the same procedure as the control group except for the aging treatment. Atomic force microscopy was used to measure surface roughness. The degree of tetragonal-to-monoclinic transformation was determined using X-ray diffraction. Nanoindentation hardness and modulus measurements were carried out on the surface of the zirconia specimens using a nanoindenter XP/G200 system. The yttria levels for nonaged and aged specimens were measured using energy dispersive spectroscopy. Flexural strength was determined using the piston-on-three-ball test. The t-test was used to determine statistical significance. Means and standard deviations were calculated using all observations for each condition and evaluated using a group t-test (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The LTD treatment resulted in increased surface roughness (from 12.23 nm to 21.56 nm for Ra and 15.06 nm to 27.45 nm for RMS) and monoclinic phase fractions (from 2% to 21%), with a concomitant decrease in hardness (from 16.56 GPa to 15.14 GPa) and modulus (from 275.68 GPa to 256.56 GPa). Yttria content (from 4.43% to 4.46%) and flexural strength (from 586 MPa to 578 MPa) were not significantly altered, supporting longer term in vivo function without biomechanical fracture. The LTD treatment induced the tetragonal-to-monoclinic transformation with surface roughening in zirconia prepared using dental procedures.
The Journal of Prosthetic Dentistry, 2012
When feldspathic porcelain (FP) laminate veneers are used to mask tooth discoloration that extend... more When feldspathic porcelain (FP) laminate veneers are used to mask tooth discoloration that extends into the dentin, significant tooth reduction is needed to provide space for the opaque layer and optimize the bonding of the restoration. The purpose of this study was to investigate the color effect of trial insertion paste (TP), composite resin abutment (CRA), and veneer regions on the optical properties of feldspathic porcelain (FP), yttria-stabilized zirconia (Y-TZP), and IPS e.max CAD HT (IEC) veneers. A melamine tooth was prepared for a laminate veneer on a model, and a definitive cast was made. The definitive die was scanned by using the TurboDent System (TDS), then 30 CRA were machined and 10 veneers were fabricated for each ceramic material (FP, Y-TZP, IEC). The optical properties of different veneer materials, CRA (A(1), A(2), A(3)) and TP (bleach XL, opaque white, transparent, and yellow) were evaluated in the cervical, body, and incisal regions with a spectrophotometer. Results were analyzed by using 1-way ANOVA (.05). The color difference for all the veneers was affected by TP and CRA colors in different regions. The mean values for the Y-TZP veneer color coordinates (L*: 74 ±0.34, a*: 0.09 ±0.20, and b*: 17.43 ±0.44) were significantly different (P&amp;amp;amp;amp;amp;amp;amp;lt;.001) from those of IEC veneers (L*: 70.15 ±0.23, a*: -0.69 ±0.073, and b*:11.48 ±0.30) and FP veneers (L*: 70.00 ±0.86, a*: - 0.28 ±0.203, and b*: 13.86 ±1.08). There was no difference between IEC for L* and FP. Significant difference was detected (P&amp;amp;amp;amp;amp;amp;amp;lt;.001) in color coordinates among the 3 veneer materials for a* and b*. The TP color affected the color difference for all veneer materials except the Y-TZP, while there was no effect on the CRA color. The magnitude of color coordinates changed as a function of TP color and veneer material.
The Journal of Prosthetic Dentistry, 2012
Fracture of feldspathic porcelain laminate veneers represents a significant mode of clinical fail... more Fracture of feldspathic porcelain laminate veneers represents a significant mode of clinical failure. Therefore, ceramic materials that withstand a higher load to fracture, especially for patients with parafunctional habits, are needed. The purpose of this study was to examine the correlation of material (zirconia, TZP, glass-ceramic, IEC, and feldspathic porcelain, FP) design (incisal overlapped preparation, IOP, and three-quarter preparation, TQP), and fracture mode to failure load for veneers supported by composite resin abutments. A typodont tooth prepared with 2 designs (IOP, TQP) and the corresponding 2 definitive dies were used to fabricate the composite resin abutments (30 for IOP and 30 for TQP). Ten veneer specimens for each system (Y-TZP, IEC, and FP), were fabricated for each design. The veneers were cemented, invested, and tested in compression until failure by using a universal testing machine. Significant differences were evaluated by 2-factor ANOVA (α=.05). No statistical mean load difference was noted between the preparation designs for Y-TZP (IOP: 244 ±81 and TQP: 224 ±58 N), IEC (IOP: 306 ±101 and TQP: 263 ±77 N), and FP veneers (IOP: 161 ±93 and TQP: 246 ±45 N). No statistical difference in the mean load was found among the 3 veneer materials for each preparation design except between IEC (306 ±101 N) and FP (161 ±93 N) veneers for TQP. Preparation design did not influence the failure load of the veneer materials. Zirconia veneers were the least likely to fracture but the most likely to completely debond; feldspathic porcelain veneers exhibited the opposite characteristics.