Fracture Resistance of Chairside CAD/CAM Lithium Disilicate-reinforced Ceramic Occlusal Veneers With and Without Margin and Full Coverage Crowns.

OBJECTIVE: The aim of this investigation was to compare the fracture resistance of chairside computer-aided design and computer-aided manufacturing (CAD/CAM) lithium disilicate-reinforced ceramic occlusal veneers with and without margin and traditional full coverage premolar crowns. METHODS AND MATERIALS: A total of 60 chairside CAD/CAM lithium disilicate-reinforced ceramic (Amber Mill, Hass Bio) restorations were designed and fabricated with a chairside CAD/CAM system (CEREC Dentsply Sirona). The restorations were divided into three groups (n=20): 1) occlusal veneer with 1.0-mm uniform occlusal thickness and with chamfer margin; 2) occlusal veneer with 1.0-mm uniform occlusal thickness and without margin; and 3) full coverage crown with uniform occlusal thickness and gingival margin. Occlusal veneers and crowns were cemented with dual cured resin luting cement (Multilink, Ivoclar Vivadent) to printed resin dies, load cycled (5 million load cycles at 1 Hz with 275 N force), and then loaded until fracture. Load at break (LB) and peak load (PL) until fracture were recorded. Scanning electron microscope images of the tested restorations on the abutments were obtained. RESULTS: Fracture strengths were different depending on the design of the restoration. There was no significant difference in fracture strength between the two types of occlusal veneer (LB: 1132.45 N; PL: 1143.30 N for veneers with margin; LB: 1149.25 N; PL: 1219.05 N for veneers without margin). Full coverage crowns showed the lowest fracture resistance (LB: 936.26 N, PL: 976.42 N), which was significantly lower than both designs of occlusal veneer. CONCLUSIONS: The fracture resistance of the CAD/CAM lithium disilicate-reinforced ceramic restorations was influenced by the design. Occlusal veneers with and without margin displayed higher fracture resistance than traditional crowns.

Evaluation of Glazing and Polishing Systems for Novel Chairside CAD/CAM Lithium Disilicate and Virgilite Crowns.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of glazing, two zirconia, and two lithium disilicate polishing systems on surface roughness of a CAD/CAM lithium disilicate and virgilite ceramic with atomic force microscopy (AFM) and visual assessment performed by dental students and faculty. METHODS AND MATERIALS: Sixty maxillary right central incisor crowns made of a novel chairside CAD/CAM lithium disilicate and virgilite (CEREC Tessera) were milled for glazing and polishing. The crowns were divided into six groups: no polishing/glazing provided (NoP/G); glazed (GZ); glazed and polished with Brasseler Dialite LD Lithium Disilicate (DiLD); glazed and polished with Meisinger Luster Lithium Disilicate (LuLD); glazed and polished with Brasseler Dialite ZR Zirconia (DiZR); and glazed and polished with Meisinger Luster Zirconia (LuZR). Surfaces were scanned with AFM to measure roughness (Ra) and root mean square roughness (Rq) and generate micrographs. Crowns were visually assessed by 10 dental students and 10 dental school faculty members to determine clinical acceptableness. RESULTS: Glazing and all polishing kits significantly reduced Ra and Rq compared to no polishing/glazing. No significant Ra differences were found between glazing and all polishing kits (p>0.05). DiZR significantly reduced Rq compared to other groups (p<0.05). Visual assessment showed that GZ, LuLD, and DiZR were the most clinically acceptable crowns. CONCLUSION: Polishing and glazing considerably improve the surface smoothness of maxillary central incisor crowns fabricated out of a chairside CAD/CAM lithium disilicate and virgilite ceramic. Altogether, zirconia polishing systems provided smoother and more clinically acceptable surfaces than the lithium disilicate kits.

Printed Digital Wax-up Model as a Blueprint for Layered Pressed-ceramic Laminate Veneers: Technique Description and Case Report.

This article presents a clinical technique for transferring Digital Smile Design (DSD) information and a digital wax-up to fabricate highly personalized ceramic laminate veneers. The hybrid workflow of digitally designed wax-up and conventional hand-crafted veneers is showcased in a female adult who sought to improve her smile due to maxillary anterior incisal wear. The ceramic veneers, layered by feldspathic porcelain, followed the contours and shade blueprint planned with the digital wax-up. The DSD improved the harmony of the facial-and-smile relationship, and the ceramic restorations fulfilled the patient's esthetic and functional demands. Guides based on the printed model with the digitally designed wax-up can provide a reference for pressed lithium disilicate veneers layered with feldspathic porcelain.

Injectable Flowable Resin-based Composite Veneers Prior to Ceramic Veneers.

OBJECTIVES: This case report describes the clinical protocols for using injectable flowable resin-based composite veneers without tooth reduction as long-term prototype restorations, followed by conservative feldspathic veneer restorations. CLINICAL CONSIDERATION: The patient's primary concern was to improve her smile. After clinical evaluation, injectable flowable resin composite veneers were recommended as long-term prototypes followed by conservative tooth preparation and ceramic veneers. Flowable composite veneers were created with a transparent silicone index fabricated from a diagnostic wax-up approved by the patient. No tooth reduction was required to place this type of composite veneer. Later, a printed reduction guide was used to provide conservative tooth preparation followed by the cementation of thin feldspathic porcelain veneers under full isolation with a rubber dam. CONCLUSIONS: Injectable flowable resin-based composite veneers can successfully act as long-term esthetic prototypes before ceramic veneers. The outcome of these restorations is very predictable because the diagnostic wax-up anatomy is transferred to the mouth through the transparent silicone index, and they can be placed without tooth reduction. Conservative tooth preparation can be performed on the composite veneers so that minimal tooth structure is removed to maximize the bonding performance of ceramic veneers.

Ultrathin Partial Ceramic Veneers in the Esthetic Zone with Tooth Whitening: A 5-year Case Report.

OBJECTIVE: This case report describes a minimally invasive approach with tooth whitening and partial ceramic veneers in the esthetic zone with a 5-year follow-up. CLINICAL CONSIDERATIONS: The patient was initially concerned about the tooth color and previous direct resin composite restorations that chipped on the incisal edges of both maxillary central incisors. Tooth whitening and partial veneers for both central incisors were recommended after clinical evaluation. Two sessions of in-office tooth whitening, first with 35% hydrogen peroxide and later with 10% carbamide peroxide from first premolar to first premolar, were provided. Minimal tooth preparation that only removed the fractured composite restorations was performed followed by placement of feldspathic porcelain ultrathin partial ceramic veneers for both central incisors. We emphasize the benefits of minimal tooth preparation paired with partial ceramic veneers and the importance of masking discolored tooth structure with such thin veneers, including potential tooth whitening. CONCLUSIONS: Overall, we demonstrate a well-planned and executed restorative procedure combining tooth whitening and ultrathin partial ceramic veneers to achieve desired results in the esthetic zone that remained successful for five years.

Polychromatic Composite and Resin Infiltration Restorations in the Esthetic Zone: A Five-year Clinical Report.

OBJECTIVE: This case report describes the use of a combination of a polychromatic resin composite restoration and resin infiltration to achieve a satisfactory esthetic outcome that has lasted over five years. CLINICAL CONSIDERATIONS: The patient's primary complaint was a desire to replace an existing stained resin composite on the facial and mesial surfaces of the maxillary left central incisor, and a white spot on the facial surface of the maxillary right central incisor. After clinical evaluation, the patient was offered either replacement of the restoration with a polychromatic restoration simulating a white spot, or a combined treatment with polychromatic composite and resin infiltration restorations, which was recommended. The patient selected the latter treatment. A putty matrix was fabricated, and a quick mock-up was done using various enamel and dentin shades of resin composite to determine proper material selection. The previous resin composite restoration was removed, and layers of new dentin, body, and enamel composite were placed. An interproximal matrix was used in order to provide ideal contour and contact. Finishing and polishing procedures were performed. The maxillary right central incisor was treated with resin infiltration in order to subdue the white spot on the facial surface. CONCLUSIONS: Polychromatic resin composite and resin infiltration restorations to replace a stained restoration and mask a white spot can achieve desired results in the esthetic zone and maintain them for five years.

Effectiveness of Different Polishing Kits for Chairside CAD/CAM Provisional Restorative Materials.

OBJECTIVE: To investigate the efficacy of three specially designed polishing kits for provisional restorations made from three chairside computer-aided design and computer-aided manufacturing (CAD/CAM) provisional resin blocks. METHOD: Ninety-six chairside CAD/CAM provisional restorations were milled out of three chairside CAD/CAM provisional resin blocks: (1) ArtBloc Temp (Merz Dental); (2) Telio CAD (Ivoclar Vivadent); and (3) Vita CAD-Temp (VITA Zahnfabrik). The provisional restorations for each material were allocated into the following groups: (1) milled restorations (no polish); (2) polished with CADMaster CAD/CAM Adjustment & Polishing Kit (CM, Shofu); (3) polished with KUT Ultimate Bisacryl (Temporaries) Polishing Kit (KU, Dental Savings Club); and (4) polished with K0330 PMMA Adjusting, Finishing & Polishing (KP, Brasseler USA). Optical profilometry and atomic force microscopy (AFM) were used to assess the surface roughness (Ra) of each provisional restoration at the microscale and nanoscale, respectively, and obtain topographical images. In addition, the milled and polished restorations were visually evaluated by 16 dentists. RESULTS: There was a strong positive correlation with Ra values between optical profilometry and AFM. Only KP significantly improved the surface roughness of CAD/CAM provisional restorations compared to the milled equivalent, regardless of material type or measurement modality (ie, lateral length scale). Although surface topography imaging with AFM revealed some shallow scratches, even for KP polished specimens, all KP polished restorations were categorized as clinically acceptable for provisional restorations in visual inspections from dentists. CONCLUSION: Specially designed polishing kits for provisional restorations did not all improve the surface roughness of chairside CAD/CAM provisional restorations, regardless of the measurement method. KP was more consistently effective in polishing milled chairside CAD/CAM provisional restorations than CM and KU.

Minimally Invasive Multidisciplinary Restorative Approach to the Esthetic Zone Including a Single Discolored Tooth.

OBJECTIVES: The case report describes a minimally invasive, multidisciplinary approach to a single discolored anterior tooth, with internal bleaching using traditional Japanese paper (Washi), a gingivoplasty with a three-dimensional (3D) printed surgical guide, and ultrathin feldspathic porcelain veneers. CLINICAL CONSIDERATION: The patient's primary concern was improving her smile. After clinical evaluation, internal tooth bleaching for the discolored tooth and gingivoplasty with restoration of the maxillary anterior six teeth and first premolars was recommended. The internal tooth whitening was accomplished with sodium perborate mixed with 30% hydrogen peroxide impregnated in Washi and sealed in the root canal with glass ionomer. Once the tooth bleaching was completed, the 3D printed surgical guide was placed in the patient's maxillary anterior region and used to guide soft tissue recontouring. After 6 months, ultrathin feldspathic porcelain veneers were placed. CONCLUSION: Well-planned restorative procedures combining internal tooth bleaching using Washi, gingivoplasty performed with electrosurgery using a 3D printed surgical guide, and ultrathin feldspathic porcelain veneers can achieve the desired results in the esthetic zone and remain successful for 4 years.

Evaluation of Polishing Systems for CAD/CAM Polymer-Infiltrated Ceramic-Network Restorations.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of five different polishing systems on a computer-aided design and computer-aided manufacturing (CAD/CAM) polymer-infiltrated ceramic-network restoration with nanoscale assessment using atomic force microscopy (AFM) and visual assessment performed by dental school senior students and faculty members. METHOD: Forty-eight full coverage crowns were milled out of polymer-infiltrated ceramic-network CAD/CAM blocks (Vita Enamic) for polishing with one company proprietary, two ceramic and two composite polishing systems. The prepared crowns were divided into six groups: (1) no polishing (control); (2) polishing with Vita Enamic Polishing Kit (VEna); (3) polishing with Shofu Porcelain Laminate Polishing Kit (SCer); (4) polishing with Brasseler Dialite Feather lite All-Ceramic Adjusting & Polishing System (BCer); (5) polishing with Shofu Composite Polishing Kit (SCom); and (6) polishing with Brasseler Composite Polishing Kit (BCom). The polished crown surface topography was observed, and surface roughness and area were measured with AFM. In addition, polished crowns were visually assessed by 15 senior dental students and 15 dental school faculty members. RESULTS: All polishing treatments significantly reduced the surface roughness and area of the crown compared with the control. SCom and BCom showed significantly higher surface area than VEna, and the SCer and BCer groups were intermediate, showing no significant difference from either VEna or SCom and BCom. There were no significant differences in surface roughness between any of the systems. Dental students and faculty members classified the groups polished with VEna, SCer, and BCer groups as clinically acceptable, and they selected BCer group as the best polished restorations and the control group as the least polished restorations. CONCLUSIONS: Ceramic and composite polishing systems produced similar polishing results as that observed using a company proprietary polishing system. However, effectiveness for polishing using a company proprietary and ceramic polishing system tends to be higher than composite polishing systems.

Factors Affecting Clinical Decision-Making and Treatment Planning Strategies for Tooth Retention or Extraction: An Exploratory Review.

Dentists are often confronted with challenges concerning the determination of the treatment type for questionable teeth (retention or extraction) in their routine dental practice. The objective of this review was to explore the available literature pertaining to the factors influencing clinical decision-making and treatment strategies of dentists regarding tooth retention or extraction. Explorative analysis of the literature was conducted based on its relevance to the subjected study area and scope. Primarily, the papers were extracted from sources such as ERIC, PubMed, Scopus, and Medline. The keywords used for searching articles include Clinical Decision-Making, Treatment Strategies, Tooth Extraction, and Tooth Retention. Papers published up to 2018 were extracted and evaluated. The analyzed studies highlighted that a successful treatment plan is based on the practitioner's knowledge, abilities, and skills as well as patients' preference, which is also a determinant of treatment success in restorative dentistry. Multidisciplinary dental treatment is generally adopted for decision making in dental clinics. Overall, the treatment plan should be based on the extensive learning and keen observation of the disease and the associated factors which enable long-term success of the treatment.

Two-piece mesostructure and vertically oriented locking screws design for implant-assisted prosthesis in the esthetic zone.

Restoration of the malaligned dental implants in the esthetic zone is a challenge for dental practitioner because of the difficulty in obtaining balance and harmony between position and color of the final prosthesis and the adjacent teeth. Mesostructure is a part of the prosthesis that located ontop of the dental implant and bearing the final prosthesis. It has a form of milled bar to bear an overdenture or as abutment used for the correction of malaligned dental implants. Such approach maintains screw-retained prosthesis option while allowing complete retrievability, improved accessibility, usage of thicker abutment screws, and acceptable esthetic outcomes. In this case report, a two-piece mesostructure was designed to correct the malposition of dental implants in the esthetic zone with 1-year follow-up system.

Effect of Layering Techniques on Polymerization Shrinkage Stress of High- and Low-viscosity Bulk-fill Resins.

CLINICAL RELEVANCE: The use of layering techniques is still advisable with many bulk-fill resins and should be the default unless a particular resin is known to not need it. SUMMARY: Objective: The purpose of this study was to investigate how layering techniques affect polymerization shrinkage stresses of high-and low-viscosity bulk-fill resins.Method: Six high-viscosity and six low-viscosity bulk-fill resins were evaluated. Aluminum blocks with a mesial-occlusal-distal (MOD) cavity were machined and randomly divided into groups for different filling techniques (bulk-fill vs horizontal layering vs oblique layering) and further subdivided according to type of resin (high- vs low-viscosity). The cuspal deflection resulting from the polymerization of bulk-fill resin bonded to a MOD cavity within an aluminum block was measured with a digimatic micrometer. Scanning electron microscopy analyses of tested resins were also conducted.Results: In the high-viscosity bulk-fill resins, cuspal deflection of the MOD cavity ranged from 11.2 to 18.2 µm with the bulk-filling technique, from 10.7 to 15.5 µm with the horizontal layering technique, and from 10.9 to 15.2 µm with the oblique layering technique. In the low-viscosity bulk-fill resins, cuspal deflection of the material ranged from 9.2 to 19.8 µm with the bulk-filling technique, from 8.2 to 15.7 µm with the horizontal layering technique, and from 8.4 to 16.4 µm with the oblique layering technique.Conclusion: Cuspal deflections for some high-and low-viscosity bulk-fill resins were significantly reduced by using layering techniques, but the resultant improvement of layering techniques was not applicable to all the bulk-fill resins used in this study.