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ePaper created 2016-03-07, 22:38:59 | version 1.38.0
Journal of Oral Science & Rehabilitation 50 Volume 2 | Issue 1/2016 NobelActive regular platform (Nobel Biocare), a taperedimplantwithaprogressivethreaddesign (TPT) and conicalconnection.The implant diam- eter of 4.3 mm and length of 11.5 mm were used for all groups. For this experimental controlled study, two synthetic bone blocks (Sawbones, Pacific Re- search Laboratories, Vashon Island, Wash., U.S.) measuring 13 cm × 18 cm × 4 cm, with two dif- ferent densities (Type II and Type IV), were used (Figs. 1a & b). The Type II solid block was of 0.85 ± 0.4 g/cm3 in density and the Type IV cellular block was of 0.45 ± 0.10 g/cm3 in density. The mechanicalpropertiesoftheartificialblocksused in the study are presented in Table 1. Eightexperimentalgroupswerecreatedasfollows: Group 1: Expert + Type II blocks + TST Group 2: Expert + Type II blocks + TPT Group 3: Intermediate + Type II blocks + TST Group 4: Intermediate + Type II blocks + TPT Group 5: Expert + Type IV blocks + TST Group 6: Expert + Type IV blocks + TPT Group 7: Intermediate + Type IV blocks + TST Group 8: Intermediate + Type IV blocks + TPT. Atotal of 320 perforations were performed, 160 perforations on each block. The allocation of samples to groups was performed according to randomizationsoftware(ResearchRandomizer),9 and after the allocation each one of the eight groups was composed of 40 samples (Fig. 2). D r i l l i n g p r o c e d u r e s The blocks were fixed to a metallic platform to reduce movement during drilling, as well as to ensurethesameexperimentalconditionsforboth operators.The drilling protocolusedwas recom- mendedbythemanufacturerandwasperformed by a calibrated operator. Instructions were pro- vided to both clinicians regarding the manner in which they were to prepare the implant bed. During drilling, an in-and-out motion and drilling in the bone for 1–2 s without stopping the hand- piece motor were performed until the drill reached the depth reference line (11.5 mm). The drilling parameters were the same for both op- erators: drilling speed of800 rpmwith no irriga- tion, and the drills were replaced after ten uses as recommended by the manufacturer. –Drilling forthe Replace SelectTapered implant in Type II and Type IVbone: The drilling started with the 2.0 mm diameter pilot drill, followed by the 3.5 mm diameter tapered drill and finished with the 4.3 mm tapered drill. – Drilling for the NobelActive implant in Type IV bone (soft-bone protocol): The drilling started with the 2.0 mm diameter drill, followed by a stepped drill with 2.4/2.8 mm diameter steps and finished with a stepped drill with 2.8/3.2 mm diameter steps. – Drilling for the NobelActive implant in Type II bone (hard-bone protocol):The drilling started Implants placed Group 1 n = 40 Group 2 n = 40 Group 3 n = 40 Group 4 n = 40 Group 5 n = 40 Group 6 n = 40 Group 7 n = 40 Group 8 n = 40 N = 320 a b c d e f g h ISQ value (mean ± S.D.) 63 ± 4e, f, g, h 63 ± 3e, f, g, h 65 ± 3e, f, g, h 65 ± 5e, f, g, h 54 ± 3 59 ± 2e, g 53 ± 2 58 ± 1e, g Implants placed Group 1 n = 40 Group 2 n = 40 Group 3 n = 40 Group 4 n = 40 Group 5 n = 40 Group 6 n = 40 Group 7 n = 40 Group 8 n = 40 N = 320 a b c d e f g h IT value (mean ± S.D. in N cm) 40 ± 2e, f, g, h 42 ± 4e, f, g, h 41 ± 5e, f, g, h 43 ± 2e, f, g, h 18 ± 2 20 ± 1 17 ± 2 19 ± 1 Table 3 Differences in primary stability were observed between different bone densities in terms of IT. The Tukey multiple comparison test showed differences favoring higher stability in Type II bone density compared with Type IV. Regarding implant design and level of experience, there were no differences in implant stability. Table 2 Differences in primary stability were observed between different bone densities and between different implant designs in terms of ISQ. The Tukey multiple comparison test showed differences favoring higher stability in Type II bone density compared with Type IV. Regarding implant design, implants with a progressive thread design in Type IV bone density favored higher stability. There were no differences in implant stability regarding level of experience. F a c t o r s a f f e c t i n g p r i m a r y s t a b i l i t y o f t a p e r e d i m p l a n t s w i t h d i f f e r e n t t h r e a d d e s i g n Table 2 Table 3 54 ± 359 ± 2e, g 53 ± 258 ± 1e, g 18 ± 220 ± 117 ± 219 ± 1