Publications by authors named "Norman Kwan"

Purpose: To compare the effect of taper, length, angle, and number of vertical axial walls on the retentive strength of a cemented crown on a partially customized hybrid abutment in the esthetic zone.

Materials And Methods: A total of 35 metal copings were used and divided into two groups. One group had 30 copings cemented to their corresponding 8-degree tapered abutment with lengths from 3 to 8 mm, increasing in 1-mm increments (5 copings per length).

View Article and Find Full Text PDF

Purpose: To investigate the resistance of an implant crown telescopically engaged to a geometrically defined hexagonal abutment with and without cement under compressive dynamic cyclic fatigue loading.

Materials And Methods: 40 crowns, 9 mm in height, were cast from prefabricated plastic copings, each telescopically engaged to a 3-mm-high machined hexagonal abutment. 20 crowns were retained with zinc phosphate cement, and 20 crowns were retained with a screw.

View Article and Find Full Text PDF

Purpose: To evaluate the effects of vertical compressive cyclic load on abutment screws and the stability of screw-retained splinted fixed dental prostheses supported by bone-level nonengaging and partially engaging abutments.

Materials And Methods: Ten standardized two-unit prostheses integrated with nonengaging and partially engaging abutments were 3D-printed and cast in nonprecious metal and attached to two implant analogs with conical connections angled 15 degrees toward the vertical axis in a resin bock. The common path of insertion for the prosthesis with partially engaging abutments to angled implant analogs was created by selectively reducing the abutment surface that obstructed the implant housing.

View Article and Find Full Text PDF

Purpose: The aim of this study was to evaluate the clinical use of a high-performance polymer, polyether ether ketone (PEEK), as a material for use in provisional fixed dental prostheses (FDPs) that can be retained by reciprocated guide surfaces of hexagonal-shaped healing abutments during dental implant treatment.

Materials And Methods: Patients requiring teeth replacement with dental implants for partially and fully edentulous cases in the maxilla and mandible were included. The provisional FDP was fabricated with hex castable copings and PEEK granules using the lost wax technique.

View Article and Find Full Text PDF

The purpose of this study was to evaluate the resistance and retention of a hexagonal abutment to crown displacement with varying crown heights (10, 12, and 14 mm) and axis of load. Implants were embedded in resin blocks at a 30 degree angle to the vertical. Crowns were made at heights of 10, 12, and 14 mm.

View Article and Find Full Text PDF