Effect of different parameters utilized for image guided endodontic root canal preparation on temperature changes: an in vitro study.

BACKGROUND: Navigated endodontics is a cutting-edge technology becoming increasingly more accessible for dental practitioners. Therefore, it is necessary to clarify the ideal technical parameters of this procedure to prevent collateral damage of the surrounding tissues. There is a limited number of studies available in published scientific literature referencing the possible collateral thermal damage due to high-speed rotary instruments used in guided endodontic drilling. The aim of our study was to investigate the different drilling parameters and their effect upon the temperature elevations measured on the outer surface of teeth during guided endodontic drilling. METHODS: In our in vitro study, 72 teeth with presumably narrow root canals were prepared using a guided endodontic approach through a 3D-printed guide. Teeth were randomly allocated into six different test groups consisting of 12 teeth each, of which, four parameters affecting temperature change were investigated: (a) access cavity preparation prior to endodontic drilling, (b) drill speed, (c) cooling, and (d) cooling fluid temperature. Temperature changes were recorded using a contact thermocouple electrode connected to a digital thermometer. RESULTS: The highest temperature elevations (14.62 °C ± 0.60 at 800 rpm and 13.76 °C ± 1.24 at 1000 rpm) were recorded in the groups in which drilling was performed without prior access cavity preparation nor without a significant difference between the different drill speeds (p = 0.243). Access cavity preparation significantly decreased temperature elevations (p < 0.01) while drilling at 800 rpm (8.90 °C ± 0.50) produced significantly less heating of the root surface (p < 0.05) than drilling at 1000 rpm (10.09 °C ± 1.32). Cooling significantly decreased (p < 0.01) temperature elevations at a drill speed of 1000 rpm, and cooling liquid temperatures of 4-6 °C proved significantly (p < 0.01) more beneficial in decreasing temperature elevations (1.60 °C ± 1.17) than when compared with room temperature (21 °C) liquids (4.01 °C ± 0.22). CONCLUSIONS: Based on the results of our study, guided endodontic drilling at drill speeds not exceeding 1000 rpm following access cavity preparation, with constant cooling using a fluid cooler than room temperature, provides the best results in avoiding collateral thermal damage during navigated endodontic drilling of root canals.

Does implant drill design influence the accuracy of dental implant placement using static computer-assisted implant surgery? An in vitro study.

BACKGROUND: The purpose of this in vitro study was to compare the accuracy of implant placement in model surgeries according to the design of the drills (straight drills or step drills) used to finalize the implant bed during pilot-guided static computer-assisted implant surgery (sCAIS). METHODS: Model surgeries were carried out on resin models randomly assigned to three study groups. Virtual planning software (coDiagnostiX 10.6, Dental Wings, Montreal, Canada) was used to plan the implant positions. In Groups 1 and 2, pilot-guided sCAIS was performed. Straight drills were used in Group 1, and step drills were used in Group 2 to finalize the implant beds. In Group 3, fully guided sCAIS was performed using a universal fully guided kit (RealGUIDE Full Surgical Kit 3DIEMME, RealGUIDE, Cantù, Como, Italy). A total of 90 dental implants (Callus Pro, Callus Implant Solutions GmbH, Nuremberg, Germany) were placed (six implants per model, five models per study group). The primary outcome variables (angular deviation, coronal global deviation, and apical global deviation) were calculated for all implants based on the comparison of the preoperative surgical plan with the postoperative scans. RESULTS: Group 2 (coronal global deviation, 0.78 ± 0.29 mm; apical global deviation, 1.02 ± 0.56 mm) showed significantly lower values of both global deviation variables than Group 1 (coronal global deviation, 0.95 ± 0.20 mm; apical global deviation, 1.42 ± 0.49 mm). However, there was no significant difference in angular deviation between Groups 1 and 2 (7.56 ± 2.92° and 6.44 ± 2.84°). Group 3 produced significantly lower values of all three primary outcome variables (angular deviation, 2.36 ± 0.90°; coronal global deviation, 0.59 ± 0.28 mm; apical global deviation, 0.90 ± 0.29 mm) than Group 1 and significantly lower angular deviation and coronal global deviation values than Group 2. CONCLUSIONS: The design of the drills used to finalize implant osteotomies during pilot-guided sCAIS influences dental implant placement accuracy. Using step drills instead of straight drills for final osteotomies decreases deviation from the surgical plan. The fully guided approach performed better than the pilot-guided sCAIS.

Comparison of surface aspects of turned and anodized titanium dental implant, or abutment material for an optimal soft tissue integration.

Objectives: Soft tissue integration of dental implants lags behind natural biological integration of teeth mainly because of non-optimal surface features. Peri-implant infections resulting in loss of supporting bone jeopardize the success of implants. Our aim was to compare an anodized surface design with a turned one for a more optimal surface. Methods: Morphological and chemical structures of turned and anodized Ti surfaces (grade 5: Ti6Al4V) discs were examined by scanning electron microscopy (SEM-EDS), energy dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM). The hydrophilic or hydrophobic features of the surfaces were determined by dynamic contact angle measurement. Results: SEM and AFM revealed significant differences in the morphology and roughness (Ra) of the samples. Anodized discs presented a granular structure, while turned ones had circular grooves. The roughness was significantly higher for the anodized samples compared to the turned ones. XPS and EDS confirmed typical elements for both Ti6Al4V samples. Due to anodization, the amount of Ti (IV) had increased and Ti (III) had decreased in the thicker oxide layer. Anodized samples resulted in a more hydrophilic surface than the turned ones. Significance: The results suggest that the tested anodized samples present optimal surface characteristics to be used as abutment material for an optimal soft tissue integration.