Perng-Ru Liu

Perng-Ru Liu
University of Alabama at Birmingham | UAB · Department of Restorative Sciences

DDS, MS, DMD

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57
Publications
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1,190
Citations

Publications

Publications (57)
Article
Soaring gold prices have created an almost impossible void in the Dental Materials supply reserves for affordable patient posterior crowns. Fortunately, aerotech fiber-reinforced composite (FRC) materials in use for many diverse structural applications can be developed for dentistry to replace gold with computer-assisted design/computer-assisted ma...
Article
Full-text available
Newer dental fiber-reinforced composites can provide service with less wear than enamel. Further, fibers in bulk molding form pack oriented parallel to the occlusal-dentinal floor planes that wear by uniform thinning into micrometer-sized fiber remnants and subsequent flat plate-like particulate bond by compression back into the polymer matrix. The...
Article
Purpose: Screw-retained zirconia implant crowns with an internal titanium base have favorable mechanical properties compared with single-piece zirconia implant crowns; however, the screw-retained implant crowns require adequate bonding between the zirconia crown and the titanium base. This study measured the retention between a titanium base and a...
Article
Full-text available
Unsaturated carbon-carbon double bonds particularly at exposed end groups of nonsolid fluids are susceptible to free-radical covalent bonding on one carbon atom creating a new free radical on the opposite carbon atom. Subsequent reactive secondary sequence free-radical polymerization can then continue across extensive carbon-carbon double bonds to...
Article
Statement of problem The clinical challenge of adhering cement to intracanal dentin is transmitting light to the most apical parts of root canals to allow more efficient polymerization of the cement. Purpose The purpose of this in vitro study was to compare the cement-polymerizing ability, microstructure, and radiopacity of a new fiber optic post...
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Three-dimensional (3D)-woven noncrimp fiber-reinforced composite (FRC) was tested for mechanical properties in the two principal directions of the main XY plane and compared to different Computer-Aided-Design/Computer-Aided-Machining (CAD/CAM) Dental Materials. The Dental Materials included ceramic with Vitablock Mark II®, ProCAD®, InCeram® Spinel,...
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Photocure fiber-reinforced composites (FRCs) with varying chopped quartz-fiber lengths were incorporated into a dental photocure zirconia-silicate particulate-filled composite (PFC) for mechanical test comparisons with a popular commercial spherical-particle amalgam. FRC lengths included 0.5-mm, 1.0 mm, 2.0 mm, and 3.0 mm all at a constant 28.2 vol...
Article
Objective This clinical report describes an alternative treatment modality for the replacement of congenitally missing maxillary lateral incisors in a 17-year-old patient.Clinical ConsiderationsZirconia-based resin-bonded fixed partial dentures (RBFPDs) were selected as a viable and conservative treatment option in a young individual with highly ae...
Article
Purpose: To determine if contamination of abutment screws with titanium nanoparticles affects the preload by measuring the reverse torque after multiple cycles of screw closing-opening. Materials and Methods: The study included 30 internal hex implants, titanium abutments, and titanium abutment screws. Fifteen abutment screws were contaminated with...
Article
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, I...
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Full-text available
Background/purpose The purpose of this study was to determine fracture loads of human maxillary first premolars restored with condensable composite resin (Surefil, Dentsply) or leucite-reinforced ceramic inlays (ProCAD, Ivoclar Vivadent) in mesial occlusal distal cavity preparations of differing pulpal depths and isthmus widths. Materials and meth...
Article
PurposeTo investigate the effects of abutment design to correct for implant angulation and aging on the fracture resistance of zirconia abutments. Greater understanding of the fracture strength of the zirconia abutments under various clinical conditions may lead to improvement of clinical protocols and possibly limit potential failures of implant p...
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Abstract Aim To evaluate the retentive strength of seven different luting agents in cement-retained implant abutment/analog assemblies.Materials and Methods Fifty-six externally hexed dental implant abutment/analog assemblies and cast superstructures were divided randomly into 7 groups for cementation with each of the 7 luting agents. Five definit...
Article
Information about the influence of zirconia crown surface treatment and cement type on the retention of zirconia crowns is limited. It is unclear whether zirconia crowns require surface treatment to enhance their retention. The purpose of this in vitro study was to evaluate the effect of surface treatment on the retention of zirconia crowns cemente...
Article
An implant-supported prosthesis is a successful treatment option for edentulous patients. This article reports on a case that has not been documented in the literature involving complications in a maxillary implant-supported bar overdenture, followed by the management of the complications.
Article
Full-text available
This clinical report presents the reconstruction of a maxillary arch with a cement retained implant supported fixed prosthesis using a monolithiczirconia generated by CAD/CAM system on eight osseointegrated implants. Theprosthesis was copy milled from an interim prosthesis minimizing occlusal adjustments on the definitive prosthesis at the time of...
Conference Paper
Full-text available
Objectives: 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 were correlated to failure load for veneers supported by composite resin abutments. Methods: A typodo...
Article
This article introduces a procedure that allows the clinician to verify the 3-dimensional spatial orientations of implant analogs in the definitive cast for a cement-retained, implant-supported prosthesis with engaging abutments. Multiple interlocking puzzle pieces are used with engaging interim abutments to verify the accuracy of the impression.
Article
Treatment planning to restore the congenitally missing lateral incisor must occur before the initiation of orthodontic treatment, with consideration given to the patient's age and development. Historically, treatment options have been very limited for teenage postorthodontic patients with this condition. More recently, the introduction of fiber-rei...
Article
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. Purpose: The purpose of this study was to examine the correlation of material (zirconia,...
Article
This investigation examined the cumu-lative survival rate of the implant-supported overdenture using two types of attachments in patients treated at Show Chwan Memorial Hospital Implant Center from 1992 to 2006. Fifty-one patients (30 men and 21 women) were treated with mandibular implant-supported overdentures. Attachment systems used were the Had...
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Full-text available
Type of Case: The fabrication of provisional prostheses is a treatment modality that is used to support and develop soft-tissue contours and improved health of a dental implant site before final restoration. The use of a provisional restoration may improve the esthetics and allow evaluation of the crown anatomy and soft-tissue interface. Developing...
Article
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 abut...
Conference Paper
Full-text available
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 t...
Article
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Purpose: 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 relat...
Article
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 zirco...
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Full-text available
Focused Clinical Question In a patient receiving intravenous infusion of nitrogen containing bisphosphonates for management of osteoporosis, is surgical implant treatment contraindicated because of the risk of impaired bony wound healing and osteonecrosis of the jaw? Clinical Scenario A 64-year-old postmenopausal woman who leads a busy life and wor...
Article
The purpose of this investigation is to evaluate marginal discrepancy and fracture resistance of two veneering materials using two preparation designs. Two veneer preparation designs (full and traditional) were restored with leucite-reinforced ceramic (ProCAD, Ivoclar Vivadent, Amherst, NY) milled by CAD/CAM (Cerec 3D milling system, Serona Dental...
Conference Paper
Full-text available
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 rest...
Conference Paper
Purpose: This study was designed to assess the biomechanical properties via nanoindentation of single-unit-dental implant modular-connection interfaces. Materials and Methods: Single-unit-dental implants (n=6) were obtained from a collection of retrieved specimens for analysis along the implant-abutment and implant-screw interfaces. Control, tens...
Conference Paper
UAB has initiated a vertically integrated clinical model involving all undergraduate DMD students. One of the goals is to allow students to be involved in patient care as early as possible. In order to accomplish this, major curricular changes have been made within the D-1 curriculum to allow time for early clinical experiences. Objective: The purp...
Article
Recent observations suggest that less bone loss may result from placing a more medialized abutment on an implant (platform switching). The objective of this study was to measure the radiographic crestal bone loss and biologic width around conventional and platform-switched implants. Implants were randomly assigned into conventional or switched cate...
Article
Background and Objective Erbium lasers are potential tools to remove caries and dental hard tissue but bond strengths of composites to those preparations are reported to be lower than conventional methods. The purpose of this study was to evaluate the effect of mechanical excavation and/or chemical alteration on bond strength of composites to laser...
Article
A variety of impression trays are used in the fabrication of fixed indirect restorations. Impressions used in the construction of fixed indirect restorations were examined for tray type, manner of use, and overall impression quality. A commercial dental laboratory provided 1403 impressions used to fabricate fixed indirect restorations during a 3-mo...
Article
To investigate the micromechanics and damage accumulation of the enamel/adhesive interface using sub-modelling and element deactivation methods. A finite element (FE) macromodel of the enamel/adhesive/ceramic interface subjected to shear bond testing was generated for mechanical analysis. The FE micromodel was constructed at the upper enamel/adhesi...
Conference Paper
Demand for esthetics and new materialshas resulted in elaborate dental ceramic systems. CAD/CAM technology (in officeand in laboratories) allows precision and accuracy of fit. TDS CAD/CAM reportedly produces accurate prothesessuch as crown copings, bridge frameworks, crowns, implant abutments/bars,veneers, inlays/onlays. Objective: to quantify an...
Conference Paper
Objectives: Cerec 3D CAD-CAM system is an effective way of generating ceramic restorations to meet clinical standards. Limited data is available concerning the effect of remaining tooth structure on marginal integrity of the restoration. The purpose of this investigation was to evaluate the effect of cavity design on marginal adaptation in various...
Conference Paper
Objective: The dental practitioner selects impression trays based on a variety of patient conditions. Certain published guidelines recommend that dual-arch trays should be used for single crowns bounded anteriorly and posteriorly by teeth and with full opposing occlusion. This investigation surveyed impressions used to fabricate indirect fixed dent...
Conference Paper
Objectives: Crestal bone loss following the restoration of a dental implant is a documented phenomenon. Recent observations suggest that less bone loss may result from placing a more medialized abutment on the implant (platform switching). The aim of this study was to measure crestal bone loss and biologic width in medialized versus same diameter a...
Article
Full-text available
The formation of a superficial layer of tiny flakes has been observed on teeth prepared by Erbium lasers. It has been suggested that removing this layer (mechanically or chemically) may increase the bond strength of the resin composite. The purpose of this study is to evaluate the effect of various etching times on bond strength of resin composite...
Article
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 provide...
Article
This study investigates the biomechanical interactions among restorative materials, cuspal preparation designs, and cement thickness in a cusp-replacing adhesive premolar restoration. Twenty-seven, 3D finite element (FE) models designed in a typical MODL restoration with three restorative materials (CAD/CAM ceramic block, indirect resin composite a...
Article
The aim of this study was to determine the relative contribution of changes in implant system, position, bone type, and loading condition on the biomechanical response of a single-unit implant-supported restoration using nonlinear 3-dimensional finite element analysis (3D FEA). FEA models of a single-unit (crown) restoration supported by the Friali...
Article
Full-text available
The purpose of this study was to record subjective patient experiences with respect to the surgical placement of dental implants and the functioning of mandibular implant-retained overdentures versus conventional dentures. Completely edentulous patients (n = 56) unable to wear a conventional mandibular complete denture were each treated with 4 one-...
Article
Few data exist regarding cement failure load and marginal leakage of castings cemented to implant-supported abutments subjected to load and thermal cycling, especially with newer cements. This study evaluated the cement failure load and marginal leakage of castings cemented to Steri-Oss abutment/analog assemblies with one of seven luting protocols...
Article
To determine the cement bond strength and marginal leakage of castings cemented to implant abutments. Fifty-six titanium abutments and castings were divided into 7 groups (n=8), 1 for each cement. Castings were cemented to abutments using 1 of 3 resin-based cements (RES, RES-B, and RES-B-P), a resin-modified glass ionomer (GI), a polycarboxylate ce...
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Full-text available
The maxillary full-arch implant-supported fixed prosthesis represents a challenge due tothe structural limitations of the existing premaxillary ridge and maxillary sinus. Prior to initiatingimplant treatment, it is critical to consider the necessary clinical and laboratory proceduresneeded to obtain an optimal level of patient and clinician satisfa...
Article
Full-text available
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 provide...
Article
This study measured bone height under a fixed detachable cantilever restoration supported by five or six endosseous implants in 60 consecutively treated patients. Panoramic films were made at surgery and 1, 2, 3, and 4 years postrestoration. A computer-enhanced method was used to measure mandibular height 5, 10, 15, and 20 mm distal to the last imp...
Article
A new technique for producing a Computer-Aided Design and Computer-Integrated Machining Ceramic Reconstruction crown is presented. After completion of the tooth preparation, an "optical" impression of the tooth was made with a charged couple device camera, and the electronic image was transferred to a computer screen. The "proposed" crown was elect...
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Full-text available
A 5-year-old Caucasian male presented with early loss of multiple deciduous teeth. All the characteristics were consistent with the diagnosis of regional odontodysplasia (ROD). Significant initial findings included premature loss of multiple primary mandibular teeth and some malformed permanent teeth. The affected teeth showed hypoplastic enamel an...
Article
As the CAD-CAM technique has been expanded to include porcelain facings, of particular interest is adapting the veneer to the prepared surface. In a comparison of the gap dimension of CAD-CAM generated veneers to those produced in the laboratory, no statistically significant differences were detected.
Article
Thesis (M.S.)--University of Alabama at Birmingham, School of Dentistry. Includes bibliographical references (leaves 88-90).

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