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ePaper created 2016-03-11, 23:13:06 | version 1.38.0
78 — issue 2016 Periodontics Article abutmentusingnonparametrictests.Data were analyzed comparatively using the WilcoxonandPearsoncorrelationtests,at a significance level of 5%. Results The mean values and standard deviations for implant and abutment placement torques (in Ncm) and RFA (in ISQ) were 53.5 ± 19.7, 67.6 ± 8.4 and 52.8 ± 2.8, re- spectively (Table 1; Figs. 3–5). Statistical analysis did not find a linear pattern between the measurements of placement torque and ISQ, either on the implant (–0.24) or the abutment (–0.18). Regarding the comparison between ISQ for the implant and abutment, despite a significantnumericaldifference(p<0.05), a linear pattern was observed (0.68). Discussion RFAisareliablemethodformeasuringthe stabilityofdentalimplantsandthisfinding has recently been reported by several au- thors.7, 9, 10, 12–15 It is commonly measured using an Osstell device immediately after implant placement or at any time during thehealingprocess,aswellasafterloading of the implants.4 Park et al. demonstrated that two different directional measure- ments are needed for RFA, since this al- lowsthedetectionofISQchangepatterns that would not be identified if only unidi- rectional measurement was used.16 This information influenced the decision- makingprocessinthepresentstudy,since two RFA measurements were taken for each implant, onefromthe buccal andthe other from the lingual aspect, and the average was then calculated. In the present study, mean values and standard deviations for placement torque (in N cm) and RFA (in ISQ) on boththe im- plant and abutment on the day of implant placement(53.5±19.7,67.6±8.4and52.8 ±2.8,respectively)wereanalyzed.Noob- vious linear pattern was observed. When the measurements of ISQ on the implant compared with placement torque were compared, the linear correlation coeffi- cient was –0.24. This corroborates the findings of Schliephake et al.17 and Akça et al.,18 yet contradicts the results of Friberg et al.19 and Turkyilmaz et al.20 When com- paring the ISQ values on the abutment with placement torque, no linear pattern was observed;the linearcorrelation coef- ficient was –0.18. Therefore, if RFA is ac- cepted as the most suitable method for determining the best time for implant loading, it can be speculated that the placementtorquemeasurementwouldbe unnecessary. However, Esposito et al.,11 in a literature review, argued that if an immediate loading approach is consid- ered among the treatment options, then the implant must be placed with a high torque, which usually exceeds 30 Ncm21 or 40N cm.22 Therefore, RFA and torque aretwodistinctmethodsforanalyzingim- plant stability and both should be consid- ered. The main difference between them is that ISQ can be measured months after implant placement, whereas torque can only be measured on the day of surgery, which makes the latter a weak method for Measurement Mean Standard Median Lower Upper N deviation Overall picture Torque (N cm) 53.5 19.7 45 25 100 17 RFA on implant (ISQ) 67.6 8.4 68 47 78 17 RFA on abutment (ISQ) 52.8 2.8 52 47 57 17 Table 1 Table 1 Main descriptive statistics of the groups for each studied measurement. Fig. 3 Association analysis between the measurements ISQ over implant vs. placement torque. Fig. 4 Association analysis between the measurements ISQ on abutment vs. installation torque. Fig.3 Fig.4 Article_Saletti_00-00.qxp_Layout 1 02.03.16 20:53 Seite 3 Torque (N cm) 53.519.7452510017 RFA on implant (ISQ) 67.68.468477817 RFA on abutment (ISQ) 52.82.852475717 Article_Saletti_00-00.qxp_Layout 102.03.1620:53 Seite 3