Showing papers by "Jaafar Abduo published in 2020"

Accuracy of static computer-assisted implant placement in anterior and posterior sites by clinicians new to implant dentistry: in vitro comparison of fully guided, pilot-guided, and freehand protocols.

Abstract: One of the challenges encountered by clinicians new to implant dentistry is the determination and controlling of implant location. This study compared the accuracy of fully guided (FG) and pilot-guided (PG) static computer-assisted implant placement (sCAIP) protocols against the conventional freehand (FH) protocol for placing single anterior and posterior implants by recently introduced clinicians to implant dentistry. Ten clinicians new to implant dentistry inserted one anterior (central incisor) and one posterior (first molar) implants per protocol in training maxillary models. The FG protocol involved drilling and implant placement through the guide, while the PG protocol controlled the pilot drilling only. The FH implant placement was completed without the aid of any guide. A total of 30 models were used, and 60 implants were inserted. The implant vertical, horizontal neck, horizontal apex, and angle deviations from planned positions were calculated. The FG protocol provided the most accurate implant placement in relation to horizontal neck (0.47 mm–0.52 mm), horizontal apex (0.71 mm–0.74 mm), and angle deviations (2.42o–2.61o). The vertical deviation was not significantly different among the different protocols. The PG protocol was generally similar to the FH protocol with a horizontal neck deviation of 1.01 mm–1.14 mm, horizontal apex deviation of 1.02 mm–1.35 mm, and angle deviation of 4.65o–7.79o. The FG protocol showed similarity in the accuracy of the anterior and posterior implants. There was a tendency for inferior accuracy for posterior implants compared with anterior implants for the PG and FH protocols. In the hands of recently introduced clinicians to implant dentistry, it appears that the accuracy of the FG protocol was superior to the other protocols and was not influenced by the position of the implants. The PG and FH protocols showed inferior accuracy for posterior implants compared with anterior implants.

Effect of Manufacturing Technique on the Accuracy of Surgical Guides for Static Computer-Aided Implant Surgery.

Abstract: PURPOSE This study aimed to evaluate the effect of different surgical guide manufacturing techniques on the accuracy of the surgical guides produced prior to implant placement. MATERIALS AND METHODS Three type of guides were compared: milled guides using a commercial milling unit (C-Mill), printed guides using a commercial 3D printer (C-Print), and printed guides using a benchtop printer (B-Print). All the guides were fabricated on a single maxillary model for anterior implant and posterior implant placement. Ten guides were produced for each group. Four accuracy variables were measured: (1) internal accuracy, (2) vertical fit, (3) guide seating distortion, and (4) drilling access horizontal and vertical deviations. All the variables were virtually measured by 3D rendering software. The Kruskal-Wallis and the Mann-Whitney U tests were conducted to evaluate the significance of the differences among the guide groups. RESULTS The C-Mill guides were significantly more accurate than the other guide groups for all the accuracy variables (P < .05). The C-Print group tended to show greater accuracy than the B-Print group, except for guide seating distortion and horizontal deviation of drilling access. However, a significant difference between the C-Print and B-Print groups was observed only for the vertical deviation of the posterior drilling access (P < .05). The location of the implant seemed to have minimal influence on the drilling access accuracy, except for the vertical deviations of C-Mill and C-Print guides, where the anterior site was associated with significantly (P < .05) greater errors than the posterior site. CONCLUSION Producing guides by milling was more accurate and less vulnerable to seating distortion in comparison to printing. Despite the overall similarity between the two printers, the commercial printer tended to produce guides with greater accuracy than the benchtop printer.

Laboratory Evaluation of Novel Implant Metal-Acrylic Prosthesis Design: Influence of Monolithic Acrylic Veneer

Abstract: Purpose To test a novel implant metal-acrylic prosthesis design in comparison to a conventional prosthesis design through simulation of cyclic masticatory loading. The novel design involved digital designing and fabrication of the framework and the matched veneering acrylic resin material. Materials and methods Ten prostheses were fabricated for each group. All the prostheses exhibited a similar external design on two implants with a distal cantilever. The conventional group comprised a milled metal framework with mechanically retained acrylic denture teeth via vertical pins. The digital prosthesis group incorporated an inverted T-shape bar and a monolithic milled acrylic resin veneer. The resin veneer was subsequently adhesively attached on the bar. All prostheses were thermally aged and subjected to laboratory cyclic loading at the cantilever region. The load-to-failure and the number of cycles until failure were collected. Furthermore, failed specimens were analyzed to determine the mode of failure. Results The digital prostheses failed at significantly greater load-to-failure (1,570.0 N ± 116.0 N) and number of cycles (124,857 ± 21,608) than the conventional prostheses (load-to-failure = 1,015.0 N ± 47.4 N; number of cycles = 28,452 ± 6,559). The conventional prostheses failed by fracturing of the acrylic teeth and veneering material that led to exposure of the metal framework. Half of the digital prostheses failed by superficial chipping of the veneering material, while the other half failed by the deformation and fracture of screws. Conclusion Within the limitations of this study, the digital prostheses with the novel design and monolithic veneering material showed significantly higher strength compared with the conventional prostheses. The mode of acrylic failure of the digital prostheses was more favorable.

Effect of modified tray design on accuracy of different impression techniques for parallel and divergent implants.

Abstract: This study evaluated the effect of a modified tray design on the accuracy of implant impressions in comparison with the non-splinted and splinted impression techniques. Two titanium frameworks were produced to fit two parallel implants and two divergent implants with a 15o angle. According to the frameworks employed, two acrylic resin master models were fabricated. For each model, 10 impressions were taken with every technique. The maximum framework principal strain was calculated for every generated cast. For the parallel implant model, the strains of the non-splinted (118.4 μe), splinted (89.0 μe), and modified tray design impression (49.4 μe) techniques were statistically similar (P = 0.16). For the divergent implant model, all the impression techniques showed a considerably higher strain than the parallel implant model. The splinted (287.0 μe) and the modified (262.9 μe) tray design impression techniques showed similar strains for the divergent implant model, which were significantly less than the strains for the non-splinted impression (518.0 μe) technique (P < 0.05). Therefore, for two parallel implants, all the impression techniques exhibited similar accuracy. When angulation existed between the implants, the splinted and the modified tray design impression techniques were more accurate than the non-splinted impression technique.