ABSTRACT
BACKGROUND: The purpose of this study was to evaluate dental impression accuracy of one-step and two-step techniques compared to a modified two-step technique. METHODS: Four impression techniques were compared: (1) a one-step double mix (DM) technique, (2) a cut-out (CO) technique, in which space relief was created using a blade and a laboratory bur, (3) a membrane (ME) technique, in which space relief was created by placing a PVC membrane on top of the putty material during the primary impression, and (4) a wiggling motion (WI) technique, in which PVC membrane was placed and additional wiggling movements were performed during the first 20 s when the primary impression was seated upon the master model (MM). Impressions were poured with type IV stone. Casts were scanned with a laboratory scanner and measurements were made for each cast using three-dimensional analysis software. RESULTS: All groups presented differences compared to MM group, in at least one intra-abutment distance. Groups DM and ME presented the most significant differences, in three and two distances, respectively, whereas CO and WI presented one significant different distance compared to MM. There were no differences between MM and the four techniques for inter-abutment distances. CONCLUSIONS: WI yielded similar results with CO technique. Both performed better than the other groups.
ABSTRACT
This case report describes the fabrication of 3 single crowns for a patient with weakened abutment teeth. The patient exhibited nocturnal bruxism and clenching but refused to use an occlusal appliance. The abutment teeth were endodontically treated and presented with loss of tooth structure and thin axial walls. The patient was seeking a metal-free restoration, and all-ceramic restorations were contraindicated because of the potential for abrasion of the opposing teeth and direct force transmission to the weak abutment teeth. The restoration of choice was a modified polyetheretherketone (PEEK) framework material veneered with an indirect light-cured composite resin. This approach offered characteristics such as biocompatibility, protection of opposing teeth, a cushioning effect, abrasion resistance almost equal to that of dentin, ease of intraoral repair in case of chipping, and a high level of comfort. The use of PEEK frameworks veneered with indirect light-cured composite resin could be a viable alternative for the treatment of weakened abutment teeth in patients with parafunctional habits.
