e., stress concentration at the bone-implant interface that leads to fibrous encapsulation around the implant rather than full osseointegration), 22 and primary stability (i.e., initial stability immediately after insertion, mainly determined by cortical bone thickness). 23 and 24 Other factors include

inflammation ABT-737 cost of the peri-implant tissue and proximity of the mini-implant to adjacent teeth, as well as the overall morphology of the patient (e.g., vertical direction of facial growth) in whom the anchorage device is inserted. 19, 20 and 21 In the current study, the overall mini-implant survival rate was 65%, with some variability when the groups were evaluated separately (G1: 71%, G2: 50%, G3: 75% and G4: 63%). There was no statistically significant difference regarding the survival rate between the groups relative to healing time (Table 1 and Table 2) and the location of insertion (maxilla or mandible; Table 3). Although there was no statistically significant difference between groups regarding the survival rate (Table 1 and Table 2), it is important to point out that G2 presented failed 50% of the time, which is relevant clinically. This result indicates that the decision

of using immediate loading should be analysed with caution, always considering some relevant aspects, such as the diameter of the mini-implant and primary stability, which are decisive Fluorouracil datasheet for obtaining success with these devices.18, 23, 24 and 25 In the present experimental study, the mini-implants remained uncovered in the oral cavity, similar to that which occurs clinically when the screws are exposed to the intraoral environment.10 and 19 In other previous investigation,5, 9, 26 and 27 the screws remained covered after insertion, being protected from external factors, which presumably can improve the success rate because the covered mini-implants are not

exposed Cyclic nucleotide phosphodiesterase to oral contamination. It may be that the reason for the success rate seen in the four groups in this study was the oral environment of the experimental animal, which presumably is less hygienic than in the typical patient. The results of the current study may indicate that maintaining good oral hygiene is a factor more critical for mini-implant success than is the timing of mini-implant loading. Some studies already have reported that loading per se does not cause the loss of stability until an overload limit is reached. 28 Microscopic findings showed that after 120 days bone remodelling was in progress, with woven bone mineralisation between the screw and lamellar bone (Fig. 3, Fig. 4, Fig. 5 and Fig. 6). Almost all the mini-implant threads were surrounded by bone tissue until the cervical area was reached, but with some interposition of connective tissue between the bone and the mini-implant, revealing a partial osseointegration (Fig. 3, Fig. 4, Fig. 5 and Fig. 6).