An analysis was performed by the same radiologist twice at two different sessions with a 1-week interval in between in an attempt to eliminate intraobserver error. The data of the two trials were pooled, and the mean was included in additional statistical analysis.
The collected data were revised, coded, tabulated, and introduced into a PC using statistical package for the social sciences (SPSS 15.0, 2001; SPSS Inc., Chicago, Illinois, USA) for windows. Data were presented and suitable analysis was carried out according to the type of data obtained for each parameter. The data are presented as mean±SD. A paired-sample T-test was used to assess the statistical significance of the difference between two means of one quantitative variable measured twice for the same study group.
The independent-sample T-test was used to assess the statistical significance of the difference between two study group means. The χ2-test was used to examine the relationship between two qualitative variables.
The study included eight patients (one was male and seven were female) seeking immediate implant placement in the maxillary anterior or premolar region. The age range of the patients included in the study was 25–45 years with a mean age of 37.75 years. The total number of implants was 12, six in each group.
The distribution of implants on the patients studied was as follows: four patients received one implant and four patients received two implants. The mean length of the utilized implants in the control group was 13 mm and the mean diameter was 3.8 mm. The mean length of the utilized implants in the study group was 12.3 mm and the mean diameter was 3.7 mm.
Successful implantation was achieved in all cases except for case number 6 in the control group (B6) whose ISQ value at 6 months postoperatively was 25 from the buccal aspect and 19 from the palatal aspect with a mean of 22. Thus, loading was not done for this implant and it missed the immediate postloading and 6-month postloading readings.
There were no statistically significant differences between control and study cases regarding changes in Osstell (ISQ) readings either for the immediate postoperative period until 3 months or until 6 months postoperatively during follow-up (Table 2).
There were no statistically significant differences between controls and patients regarding changes in probing depth from the immediate postloading period until 6 months postloading during the follow-up period (Table 3).
The means changes in radiodensity readings immediately postoperatively until 1, 3, 6, and 12 months were higher in the study group than in the control group and those changes were statistically significant (Table 4).
The mean changes in vertical bone loss readings immediately postoperatively until 1, 3, 6, and 12 months postoperatively were lower in the study group than in the control group. Those changes were statistically significant at 1 month postoperatively and highly significant at 3, 6, and 12 months postoperatively (Table 5).
Dental implants have become a predictable treatment modality for prosthetic restoration in fully or partially edentulous patients. Immediate implant placement offers many advantages including reduction in treatment time, preservation of alveolar bone, maintenance of ideal soft-tissue contours, and better implant placement 28.
However, the time needed before implant loading is longer than that required in the delayed implant placement protocol 4.
In the present study bone enhancement using PEMFs was used to fasten bone healing and osseointegration in an attempt to shorten the healing time in immediate implantation. This could also shorten the overall treatment time of the implantation procedure.
The use of PEMFs was found to decrease the amount of vertical bone loss statistically significantly in the study group when compared with the control group before implant loading.
Increased radiodensity around orthopedic implants enhanced by PEMFs has been reported in previous studies 24–26. In the current study there was a statistically significant increase in radiodensity around enhanced bone in the study group.
However, all the previous studies included unloaded implants unlike the current research in which radiodensity was measured around dental implants before and after loading.
The assessment of dental implant osseointegration presents a problem because of the few credible methods.
The gold standard method used to evaluate the degree of osseointegration was microscopic or histologic analysis. However, because of the invasiveness of this method and related ethical issues, various other methods or analyses have been proposed, such as radiographs, cutting torque resistance, reverse torque, modal analysis, and recently RFA 29.
Osseointegration of immediate dental implants was investigated in this study using the RFA, which is an indirect indication of osseointegration that has been achieved at two levels: primary stability (mechanical fixation) and secondary stability (biological fixation) 30,31.
The Osstell device translates the RFA value into ISQ index. Classically, the ISQ value was found to vary between 40 and 80, where higher ISQ values correspond to higher implant stability 29.
The results regarding the ISQ values showed that in both the study and the control group the ISQ values increased at 3 and 6 months postoperatively, and this increase at 3 months postoperatively was higher in the study group than in the control group but this difference was not statistically significant. This could be explained by the small sample size.
The change in ISQ values of the study group from 3 months postoperatively until 6 months postoperatively was lower than that of the control group. Although statistically insignificant, which may be due to the small sample size, early loading of the implants at 3 months postoperatively can be recommended when using PEMFs, thus shortening the treatment time with relevant patient satisfaction.
It has been found that implant loading requires ISQ reading of 65 or more, whereas an ISQ lower than 50 may indicate potential failure 29. In the present study, case number 6 in the control group (B6) had a mean ISQ value of 22 at 6 months postoperatively. However, its bone density reading was not abnormally reduced.
The above-mentioned case could explain the present study finding that, although a statistically significant increase in bone density between two groups has been found, there was no statistically significant difference between the two groups in terms of Osstell readings. The relation between bone density and Osstell readings has been investigated with respect to primary implant stability, wherein higher bone density was associated with better primary stability, which is consistent with logical thinking in which primary stability is mechanical in origin 32.
However, there has been no previous research correlating bone density with secondary implant stability, which is biological in origin.
From the present limited series of patients, it can be concluded that PEMFs have an enhancing effect on bone healing around immediate dental implants. This enhancement tool might be an effective method in enhancement of osseointegration as Osstell readings at 3 months postoperatively are comparable to the value needed for implant loading and to 6-month readings.
This beneficial effect can be used in turn to shorten treatment time in immediate dental implant protocol or in cases when osseointegration is questionable.
Conflicts of interest
There are no conflicts of interest.
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