Mean Implant Stability Quotient Research Articles

Long-Term Follow-Up of the Sinus Membrane Elevation Technique for Maxillary Sinus Implants Without the Use of Bone Grafts or Bone Graft Substitutes in Order to Facilitate Bone Formation

Long-Term Follow-Up of the Sinus Membrane Elevation Technique for Maxillary Sinus Implants Without the Use of Bone Grafts or Bone Graft Substitutes in Order to Facilitate Bone Formation

Stability, Survival, and Tolerability of a Novel Baha Implant System

Determination of the difference in implant stability between a novel Baha implant system (test) and the previous-generation implant system (control). In an open, randomized, prospective multicenter clinical investigation, 77 adult patients with Baha implants were included. Test and control implants were randomly assigned in proportions of 2:1. Implant stability quotient (ISQ) values were recorded using resonance frequency analysis at the time of implantation and at 10 days, at 4, 6, 8, and 12 weeks, and at 6 months after surgery. Skin reactions were evaluated according to the Holgers classification. Sound processor fitting was performed from 6 weeks after implantation. Significantly higher mean ISQ values, measured between 0 and 6 months, were obtained for test compared to control implants (70.4 versus 65.4, p < 0.0001). Statistically significant differences were obtained for the study population as a whole and for the subgroup of patients loaded at 6 ± 1 weeks after implant surgery (63.6% of patients). Up to 12 weeks, Holgers rates were comparable, whereas at 6 months, more skin reactions (Grades 1 and 2) were observed in the control implant group. No reduction in mean ISQ values was observed after implant loading. The test implant showed higher mean ISQ values at the time of placement and over time. The level of osseointegration reached with the implants in adults as early as 6 weeks after implantation was sufficient to support the sound processor. The test implant system is expected to provide additional benefits related to the improvement of the degree of osseointegration, especially for patients with thin or compromised bone.

The Effect of Bovine Bone Graft With or Without Platelet-Rich Plasma on Maxillary Sinus Floor Augmentation

The purpose of this study was to compare Unilab Surgibone (USB) (Mississauga, Ontario, Canada), a bone xenograft (bovine), with platelet-rich plasma (PRP) and USB without PRP to augment the human maxillary sinus in preparation to receive dental implants. Patients who had bilateral pneumatized maxillary sinuses were included. Sinuses on one side were augmented with the USB-PRP combination and formed the study group, whereas the opposite-side sinuses were augmented with USB alone and served as controls. Bone biopsy specimens were taken during implant placement at 6.8 ± 0.9 months after maxillary sinus floor augmentation. Resonance frequency analysis measurements were performed at implant placement (first control) and before the prosthetic stage (second control), at 6.5 ± 0.7 months after implant surgery. There were 10 patients (7 men and 3 women; mean age, 53.7 ± 0.8 years). Integration between new bone and residual grafts was histologically observed in all samples. The volumes of soft tissue were 59.9% ± 7.5% and 57.8% ± 4.4% in the control and study groups, respectively; residual graft, 21.9% ± 6.6% and 23.6% ± 5.9%, respectively; new bone, 15.8% ± 4.8% and 16.0% ± 3.8%, respectively; and trabecular bone, 64.7% ± 22.5% and 69.1% ± 18.6%, respectively. A positive correlation was found between new bone volume and trabecular bone volume (P = .0001). The mean Implant Stability Quotient (ISQ) values were 71.7 ± 4.9 and 70.3 ± 5.7 in the control and study groups, respectively, at first control and 75.4 ± 6.4 and 74.4 ± 6.4, respectively, at second control. The mean ISQ values at second control in both groups were significantly higher than at first control (P = .043 and P = .028, respectively). No statistically significant differences were observed between groups (P > .05). The combination of USB and PRP does not have any effect on new bone formation and implant stabilization.

Relationship between the bone density estimated by cone‐beam computed tomography and the primary stability of dental implants

The aims of this study were to objectively assess bone quality with density values obtained by cone-beam computed tomography (CBCT) and to determine the correlations between bone density and primary stability of dental implants. Eighteen Straumann implants were inserted into 18 fresh femoral heads of swine. The bone densities of implant recipient sites were preoperatively determined by the density value using CBCT. The maximum insertion torque value of each implant was recorded using a digital torque meter. Resonance frequency, which represented a quantitative unit called the implant stability quotient (ISQ), was measured using an Osstell Mentor immediately after the implant placement. Spearman's correlation coefficient was calculated to evaluate the correlations among density values, insertion torques, and ISQs at implant placement. The density values ranged from 98 to 902. The mean density value, insertion torque, and ISQ were 591 ± 226, 13.4 ± 5.2 Ncm, and 67.1 ± 8.1, respectively. Statistically significant correlations were found between the density values and insertion torque (r(s) =0.796, P<0.001), density values and ISQ (r(s) =0.529, P=0.024), and insertion torque and ISQ (r(s) =0.758, P<0.001). The bone quality evaluated by specific CBCT showed a high correlation with the primary stability of the implants. Hence, preoperative density value estimations by CBCT may allow clinicians to predict implant stability. Whether the density values obtained by the CBCT device used in the present study could be applied to other devices requires further elucidation.

Changes in Implant Stability Using Different Site Preparation Techniques: Twist Drills versus Piezosurgery. A Single‐Blinded, Randomized, Controlled Clinical Trial

The objective of the present investigation was to longitudinally monitor stability changes of implants inserted using traditional rotary instruments or piezoelectric inserts, and to follow their variations during the first 90 days of healing. A randomized, controlled trial was conducted on 20 patients. Each patient received two identical, adjacent implants in the upper premolar area: the test site was prepared with piezosurgery, and the control site was prepared using twist drills. Resonance frequency analysis measurements were taken by a blinded operator on the day of surgery and after 7, 14, 21, 28, 42, 56, and 90 days. At 90 days, 39 out of 40 implants were osseointegrated (one failure in the control group). Both groups showed an initial decrease in mean implant stability quotient (ISQ) values: a shift in implant stability to increasing ISQ values occurred after 14 days in the test group and after 21 days in the control group. The lowest mean ISQ value was recorded at 14 days for test implants (97.3% of the primary stability) and at 21 days for the control implants (90.8% of the primary stability). ISQ variations with respect to primary stability differed significantly between the two groups during the entire period of observation: from day 14 to day 42, in particular, the differences were extremely significant (p < .0001). All 39 implants were in function successfully at the visit scheduled 1 year after insertion. The findings from this study suggest that ultrasonic implant site preparation results in a limited decrease of ISQ values and in an earlier shifting from a decreasing to an increasing stability pattern, when compared with the traditional drilling technique. From a clinical point of view, implants inserted with the piezoelectric technique demonstrated a short-term clinical success similar to those inserted using twist drills.

Comparison of Implant Stability by Means of Resonance Frequency Analysis for Flapless and Conventionally Inserted Implants

Resonance frequency analysis (RFA) is a noninvasive technique for the quantitative assessment of implant stability. Information on the implant stability quotient (ISQ) of transmucosally inserted implants is limited. The aim of this investigation was to compare the ISQ of conventionally inserted implants by raising a muco-periostal flap with implants inserted using a flapless procedure. Forty elderly patients with complete edentulous maxilla were consecutively admitted for treatment with implant-supported prostheses. A computer tomography was obtained for the computer-assisted implant planning. One hundred ten implants were placed conventionally in 23 patients (flap-group) and 85 implants in 17 patients by means of the flapless method (flapless-group) using a stereolithographic template. RFA measurements were performed after implant placement (baseline) and after a healing time of 12 weeks (reentry). All implants exhibited clinically and radiographically successful osseointegration. Bone level did not change significantly neither for genders nor type of surgical protocol. Mean ISQ values of the flapless-group were significantly higher at baseline (p < .001) and at reentry (p < .001) compared with the flap-group. The ISQ values were significantly lower at reentry compared with baseline for the flap-group (p = .028) but not for the flapless-group. This group showed a moderate, but insignificant increase. RFA measurements of males resulted in ISQ values that were thoroughly higher as compared with females at both time-points in both groups. Correlation between RFA and bone level was not found. The flapless procedure showed favorable conditions with regard to implant stability and crestal bone level. Some changes of the ISQ values that represent primary (mechanical) and secondary (bone remodeling) implant stability were observed in slight favor of the flapless method and male patients. In properly planned and well-selected cases, the minimal invasive transmucosal technique using a drill-guide is a safe procedure.

Effect of bone quality and implant surgical technique on implant stability quotient (ISQ) value

PURPOSEThis study investigated the influence of bone quality and surgical technique on the implant stability quotient (ISQ) value. In addition, the influence of interfacial bone quality, directly surrounding the implant fixture, on the resonance frequency of the structure was also evaluated by the finite element analysis.MATERIALS AND METHODSTwo different types of bone (type 1 and type 2) were extracted and trimmed from pig rib bone. In each type of bone, the same implants were installed in three different ways: (1) Compaction, (2) Self-tapping, and (3) Tapping. The ISQ value was measured and analyzed to evaluate the influence of bone quality and surgical technique on the implant primary stability. For finite element analysis, a three dimensional implant fixture-bone structure was designed and the fundamental resonance frequency of the structure was measured with three different density of interfacial bone surrounding the implant fixture.RESULTSIn each group, the ISQ values were higher in type 1 bone than those in type 2 bone. Among three different insertion methods, the Tapping group showed the lowest ISQ value in both type 1 and type 2 bones. In both bone types, the Compaction groups showed slightly higher mean ISQ values than the Self-tapping groups, but the differences were not statistically significant. Increased interfacial bone density raised the resonance frequency value in the finite element analysis.CONCLUSIONBoth bone quality and surgical technique have influence on the implant primary stability, and resonance frequency has a positive relation with the density of implant fixture-surrounding bone.

Predictability of the resonance frequency analysis in the survival of dental implants placed in the anterior non-atrophied edentulous mandible

Dental primary implant stability is considered essential in the success of the osseointegration process. The recent advent of the resonance frequency analysis (RFA) seems to effectively measure primary implant stability, although its relationship with implant survival has to be further established. Seventy patients with complete mandibular edentulism underwent dental implant rehabilitation by means of the placement of 68 dental implants within the interforaminal region and subsequent placement of an overdenture. Primary implant stability was measured by means of RFA and it was expressed in terms of implant stability quotient (ISQ) on the day of the implant insertion and at the time of the healing abutment placement in a conventional implant two-stage surgical procedure. Overall implant survival rate was 97.1% at the end of the follow-up period. The mean ISQ value for 3.75 and 4.25 mm diameter implants was 78.4 ± 5.46 and 80.83 ± 5.35 respectively, at the time of the implant placement; and 76.68 ± 4.34 and 78.22 ± 6.87 respectively, at the second surgical stage. No statistical differences were observed in relation to changes in mean ISQ value along the healing process. No statistical differences in terms of primary and secondary implant stability measured by RFA exists between 3.75 mm and 4.25 mm diameter implants in the conventional implant two-stage surgical procedure in patients with non-atrophied edentulous mandible being restored with an overdenture. Furthermore, no statistical association between RFA and the implant insertion torque was observed for endosseous dental implant placement at the first surgical stage.

Immediate Loading of Two Implants Supporting a Magnet Attachment-Retained Overdenture: One-Year Clinical Study

The aim of this 1-year evaluation was to assess the stability of implants and the responses of the supporting tissues to magnet-retained mandibular implant overdentures. Six patients with completely edentulism were enrolled in this study. Each patient received 2 implants with sandblasted with large-grit and acid-etched surfaces in the interforaminal region. The implants were loaded immediately with magnet attachment-retained overdentures. The stability of the implants and periimplant tissues was examined by performing clinical examinations, resonance frequency analysis, and radiographic examinations at 1, 2, 6, 12, and 24 weeks and 1 year after surgery. Two implants in 2 patients failed. The surviving implants were clinically and radiographically stable. The mean Implant Stability Quotient values were relatively stable, showing no significant differences (P > 0.05). The crestal bone changes were -1.18 ± 0.68 mm, -1.35 ± 0.69 mm, -1.47 ± 0.68 mm, and -1.51 ± 0.74 mm at the follow-up check performed at 6, 12, and 24 weeks and 1 year, respectively. The bleeding on probing index was not significant. The immediate loading of 2 implants using magnet attachment-retained mandibular overdentures may be a viable treatment option in cases of complete arch edentulism. This clinical approach offers increased stability to conventional dentures.

Mandibular single-implant overdentures: preliminary results of a randomised-control trial on early loading with different implant diameters and attachment systems

To determine surgical and prosthodontic outcomes of mandibular single-implant overdentures, opposing complete maxillary dentures, using a wide diameter implant and large ball attachment system compared with different regular diameter implants with standard attachment systems. Thirty-six edentulous participants (mean age 68 years, SD 9.2) were randomly assigned into three treatment groups (n=12). A single implant was placed in the mandibular midline of participants to support an overdenture using a 6-week loading protocol. The control group received Southern regular implants and standard ball attachments. One group received Southern 8-mm-wide implants and large ball attachments. Another group received Neoss regular implants and Locator attachments. Parametric and non-parametric tests of a statistical software package (SPSS) were used to determine between groups differences in marginal bone loss, implant stability, implant, and prosthodontic success (P<0.05). Implant success after 1 year was 75% for Southern regular implant (control) group; and 100% for the Southern wide and Neoss regular implant groups (P=0.038). Mean marginal bone loss at 1 year was 0.19 mm (SD 0.39) without significant differences observed. Implant stability quotient (ISQ) at baseline was significantly lower for the Southern regular (control) group than the other two groups (P=0.001; P=0.009). At 1 year, no significant difference in implant stability was observed (mean ISQ 74.6, SD 6.1). The change in implant stability from baseline to 1 year was significant for the control group (P=0.025). Prosthodontic success was comparable between the groups but the maintenance (41 events overall, mean 1.2) was greater for the Locator and the standard ball attachments. Mandibular single-implant overdentures are a successful treatment option for older edentulous adults with early loading protocol using implants of different diameters and with different attachment systems.

Alveolar split osteotomy for the treatment of the severe narrow ridge maxillary atrophy: a modified technique

Alveolar bone splitting and immediate implant placement have been proposed for patients with severe atrophy of the maxilla in the horizontal dimension. A new modification of the classical alveolar bone splitting for the treatment of the narrow ridge in the maxilla is provided. Thirty-three dental implants in eight consecutive patients were evaluated retrospectively following the described modified split-crest osteotomy. Inclusion criteria were: inadequate maxillary buccolingual dimension, 3-4mm of crestal width, and sufficient height from alveolar ridge tip to maxillary sinus floor. Primary stability was calculated using resonance frequency analysis (RFA). Alveolar bone height was measured in the panorex pre- and postoperatively. Histological bone examination was assessed following trephine bone harvesting during the second operation. Mean follow-up was 28.33 months. Bone regeneration of the inter-cortical gap occurred in 98% of implant sites (implant survival rate 100%). Mean implant stability quotient (ISQ) for the whole series of implants was 69.48. At the second operation, mean loss of the alveolar bone height was 0.542mm. Predictable results are obtained using the modified split-crest osteotomy. This technique provides an acceptable inter-cortical gap, decreases the risk of necrosis of the outer cortex, and provides a firm-wall box for the placement of particulate bone grafting.

A 1-Year Controlled Clinical Trial of Immediate Implants Placed in Fresh Extraction Sockets: Stability Measurements and Crestal Bone Level Changes

The aim of this study was to measure stability and crestal bone level changes of implants placed in fresh extraction sockets in elderly patients. Thirty-five patients who were in need of tooth extractions were recruited for this study. They received a total of 65 implants in both jaws to support fixed or removable prostheses. The teeth were carefully extracted, the implants set directly in the root socket, and resonance frequency analysis (RFA) measurements were simultaneously performed (Time 1=T1). After a healing time of 6 to 10weeks the measurements were repeated (Time 2=T2). Orthograd periapical radiographs were taken when the new prostheses were fabricated and after 1year of loaded period. The distance between the first visible bone implant contact (BIC) and the implant-shoulder was measured and crestal bone loss was calculated (ΔBIC). Mean RFA and BIC were compared for various subgroups (p<.05). By means of a fixed effects model, the impact of the parameters gender, jaw, and prosthetic indication on RFA measurements was analyzed (p<.016). The mean implant stability quotient (ISQ) values were 64.4±6.7 at T1 and 64.0±at 8.6T2, with a trend to higher values for male patients. The mixed model showed that only the jaw had a statistically significant impact on ISQ values, with higher values for the mandible. Mean crestal bone loss was small with 0.49±0.81mm, ranging form 0.1 to 2.4mm. Twenty percent of the implant sites lost more than 1-mm crestal bone. No differences were found in subgroups. Good primary and secondary stability of the implants was reached in both jaws. Crestal bone loss was small but may not be fully predictable for a single site. This treatment modality can be applied successfully in elderly patients and can be suggested for various prosthetic indications in both jaws.

Factors influencing resonance frequency analysis assessed by Osstell™mentor during implant tissue integration: II. Implant surface modifications and implant diameter

To monitor the development of the stability of Straumann tissue-level implants during the early phases of healing by resonance frequency analysis (RFA) and to determine the influence of implant surface modification and diameter. A total of twenty-five 10 mm length implants including 12 SLA RN v4.1 mm implants, eight SLActive RN v4.1 mm implants and five SLA WN v4.8 mm implants were placed. Implant stability quotient (ISQ) values were determined with Osstell mentor at baseline, 4 days, 1, 2, 3, 4, 6, 8 and 12 weeks post-surgery. ISQ values were compared between implant types using unpaired t-tests and longitudinally within implant types using paired t-tests. During healing, ISQ decreased by 3-4 values after installation and reached the lowest values at 3 weeks. Following this, the ISQ values increased steadily for all implants and up to 12 weeks. No significant differences were noted over time. The longitudinal changes in the ISQ values showed the same patterns for SLA implants, SLActive implants and WB implants. At placement, the mean ISQ values were 72.6, 75.7 and 74.4, respectively. The mean lowest ISQ values, recorded at 3 weeks, were 69.9, 71.4 and 69.8, respectively. At 12 weeks, the mean ISQ values were 76.5, 78.8 and 77.8, respectively. The mean ISQ values at all observation periods did not differ significantly among the various types. Single ISQ values ranged from 55 to 84 during the entire healing period. Pocket probing depths of the implants ranged from 1 to 3 mm and bleeding on probing from 0 to 2 sites/implant post-surgically. All ISQ values indicated the stability of Straumann implants over a 12-week healing period. All implants showed a slight decrease after installation, with the lowest ISQ values being reached at 3 weeks. ISQ values were restored 8 weeks post-surgically. It is recommended to monitor implant stability by RFA at 3 and 8 weeks post-surgically. However, neither implant surface modifications (SLActive) nor implant diameter were revealed by RFA.

Immediate/Early Function of Neoss Implants Placed in Maxillas and Posterior Mandibles: An 18‐Month Prospective Case Series Study

An increasing number of studies show that immediate/early function of dental implants can be as successful as two-stage procedures. However, the results may not be universal for all implant types and it is important that new implants are tested for this treatment modality. The aim was to evaluate an immediate/early function protocol in the maxilla and in the posterior mandible using Neoss implants (Neoss Ltd., Harrogate, UK). A total of 21 patients were provided with 69 Neoss implants (4 mm in diameter and 9-15 mm in length) and a provisional bridge within 7 days (mean 4.6 days). Sixteen implants were placed in immediate extraction sites where seven were treated with autologous bone grafts (n = 6) or bone grafts + resorbable membrane (n = 1). A final fixed prosthesis was made 3 to 6 months later. The patients were followed-up with clinical examinations for 18 months. In addition, the implants were monitored with resonance frequency analysis (RFA) measurements at surgery and after 1, 2, and 6 months. Intraoral radiographs were taken after surgery and after 1, 6, and 18 months. One implant in an extraction site in the maxilla failed after 1 month, giving a survival rate of 98.5% after 18 months. The mean marginal bone loss was 0.7 mm (SD 0.7) after 18 months. RFA showed a mean implant stability quotient (ISQ) value of 68.1 (SD 8.8) at surgery, which increased to 73.7 (SD 5.7) after 6 months. The primary stability for maxillary and mandibular implants was similar, although mandibular implants showed slightly higher values with time. Implants in extraction sockets showed a lower initial stability than in healed sites, ISQ 65.8 (SD 7.5), which increased to ISQ 67.5 (SD 6.9) after 6 months. The failed implant showed an ISQ of 74 at placement, which decreased to 42 1 month after surgery. Within the limitations of the present study, it is concluded that immediate/early function with Neoss implants is a reliable method with an implant survival rate comparable to that of the traditional two-stage protocol.

Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures

To determine the primary stability of the Southern wide diameter (8 mm) implants, Neoss regular diameter (4 mm) implants, and Southern regular diameter (3.75 mm) implants placed in the midline of edentulous mandibles for single-implant overdentures. Variables related to host site and implant characteristics were investigated to determine their influence on the primary stability of the implants. A total of 36 implants were placed in the midline symphysis of the edentulous mandibles of 36 participants. Their primary stability was then measured using the magnetic Osstell mentor device. Analysis of variance (ANOVA) was used to compare the mean implant stability quotient (ISQ) scores with one-way ANOVA for multiple comparisons. The highest measurement (ISQ) of primary stability was for the Southern 8 mm wide diameter implants (84.8, SD 9.8), followed by the Neoss 4 mm regular diameter (82.3, SD 4.8) implants and the Southern 3.75 mm regular diameter implants (75.3, SD 8.4), respectively. The Southern 3.75 mm regular diameter implants had a significantly lower mean ISQ value than the same system 8 mm wide diameter (P=0.004) and the Neoss 4 mm regular diameter implants (P=0.03). No significant differences were observed between the 8 mm and the 4 mm diameter implants (P>0.05). Host-site variables such as age, gender, bone volume, and quality do not appear to influence the primary stability of the implants. No clear correlation was established between ISQ values and implant diameter.

Which device is more accurate to determine the stability/mobility of dental implants? A human cadaver study

Non-invasive devices including resonance frequency (RF) analysis and mobility measuring (MM) damping capacity assessment are used to measure implant stability/mobility. The aims of the study were to compare the primary stability of implant inserted into extraction sockets by using RF with cable, RF wireless and new wireless MM device, to clarify the relation between these devices and to understand the correlations between peri-implant bone levels and implant stability. A total of 30 screw-type implants (3.75 x 11 and 4.2 x 11 mm) were inserted into extraction sockets of eight mandibular pre-molar regions of human cadavers. The primary stability of implants was measured by three devices after insertion. Peri-implant vertical defects were created in millimetre increments ranging between 0 and 5 mm, and stability/mobility of implants were analysed. At placement, the mean implant stability quotient of RF with cable, RF wireless and MM device values was 46 +/- 1, 57.8 +/- 9 and -5.4 +/- 1, respectively. Statistical correlations were demonstrated between these devices (P = 0.001). Statistically significant differences were presented for all peri-implant detects ranging between 0 and 5 mm for RF with cable and RF wireless at all increments. However, only a significant decrease was found between 0 and 1 mm defects, and 4 and 5 mm defects in MM device. Although RF with cable and RF wireless seem to be suitable to detect peri-implant bone loss around implants in 1 mm increments, the new MM device may not be suitable to detect the 1 mm peri-implant bone changes in human dried cadaver mandibles.

Is the osseointegration of immediately and delayed loaded implants the same?—comparison of the implant stability during a 3‐month healing period in a prospective study

The objectives of the present study were (1) to compare the stability of delayed loaded (DL) and immediately loaded (IL) ITI SLA implants during the first 3 months of the healing period using resonance frequency analysis (RFA) and (2) to determine the factors that affect implant stability during the healing period. To compare implant stability, RFA was performed on two groups of patients (12 patients received 25 IL implants and 47 patients received 79 DL implants) with a total 104 ITI SLA implants. Implant stability was measured directly by RFA at implant placement and consecutively once a week for 12 weeks. Statistical analyses were carried out to study implant stability differences between IL and DL groups. One of the 25 implants in the IL group failed, and no implant was lost in the DL group. Implant stability between the IL and DL groups showed a statistically significant difference (P<0.05). The mean implant stability quotient of all measured implants from implant insertion to 12 weeks was 72.88 +/- 5.39 for the DL and 75.86 +/- 3.60 for the IL types. The lowest stability was at 4 weeks for DL implants (mean: 71.58 +/- 5.11) and 2 weeks for IL implants (mean: 71.33 +/- 2.97). In both groups, bone types I and II showed higher implant stability than bone type III (P<0.05). The findings of this study indicate that differences in osseointegration between IL and DL implants may be predicted according to differential implant stability.

Resonance frequency measurements in vivo and related surface properties of magnesium‐incorporated, micropatterned and magnesium‐incorporated TiUnite®, Osseotite®, SLA® and TiOblast® implants

To investigate implant stability using resonance frequency measurements of topographically changed and/or surface chemistry-modified implants in rabbit bone. Six groups of microstructured, screw-shaped titanium implants: two oxidized, cation-incorporated experimental implants [Mg implants and MgMp implants with micropatterned thread flanges (80-150 microm wide and 60-70 microm deep)] and four commercially available clinical implants (TiUnite((R)), Osseotite((R)), SLA((R)), and TiOblast((R))) were installed in 10 rabbit tibia for 6 weeks. The surface properties of the implants were characterized in detail using several analytical techniques. Implant stability was measured using a resonance frequency analyzer (Osstell(TM)). Surface characterization of the implants revealed microstructured, moderately rough implant surfaces varying 0.7-1.4 mum in S(a) (mean height deviation), but with clear differences in surface chemistry. After 6 weeks, all implants showed statistically significantly higher increases in implant stability. When compared with one another, MgMp implants showed the most significant mean implant stability quotient (ISQ) value relative to the others (P<or=0.016). In terms of increment (DeltaISQ) in implant stability, MgMp implants showed a significantly greater value as compared with Osseotite((R)) (P<or=0.005), TiOblast((R)) (P<or=0.005), TiUnite((R)) (P<or=0.005), SLA((R)) (P<or=0.007), and Mg implants (P<or=0.012). In addition, transducer direction dependence of resonance frequency analysis (RFA) measurements was observed such that the differences in the mean ISQ values between longitudinal and perpendicular measurements were significant at implant placement (P<or=0.004) and after 6 weeks (P<or=0). The present study found that implant surface properties influence RFA measurements of implant stability. Surface chemistry-modified titanium implants showed higher mean ISQ values than did topographically changed implants. In particular, cation (magnesium)-incorporated micropatterns in MgMp implants may play a primary role in DeltaISQ.

Stability change of chemically modified sandblasted/acid‐etched titanium palatal implants. A randomized‐controlled clinical trial

The aim of this randomized-controlled clinical study was to examine stability changes of palatal implants with chemically modified sandblasted/acid-etched (modSLA) titanium surface compared with a standard SLA surface, during the early stages of bone healing. Forty adult volunteers were recruited and randomly assigned to the test group (modSLA surface) and to the control group (SLA surface). The test and control implants had the same microscopic and macroscopic topography, but differed in surface chemistry. To document implant stability changes resonance frequency analysis (RFA) was performed at implant insertion, at 7, 14, 21, 28, 35, 42, 49, 56, 70 and 84 days thereafter. RFA values were expressed as an implant stability quotient (ISQ). Immediately after implant installation, the ISQ values for both surfaces tested were not significantly different and yielded mean values of 73.8+/-5 for the control and 72.7+/-3.9 for the test surface. In the first 2 weeks after implant installation, both groups showed only small changes and thereafter a decreasing trend in the mean ISQ levels. In the test group, after 28 days a tendency towards increasing ISQ values was observed and 42 days after surgery the ISQ values corresponded to those after implant insertion. For the SLA-control group, the trend changed after 35 days and yielded ISQ values corresponding to the baseline after 63 days. After 12 weeks of observation, the test surface yielded significantly higher stability values of 77.8+/-1.9 compared with the control implants of 74.5+/-3.9, respectively. The results support the potential for chemical modification of the SLA surface to positively influence the biologic process of osseointegration and to decrease the healing time.

Relationship between dental implant stability determined by resonance frequency analysis measurements and peri‐implant vertical defects: an in vitro study

Resonance frequency (RF) analysis is a non-invasive and objective technique developed for implantology, where it measures the stability of the implant in the bone socket. A limited number of studies were performed to compare different stability measurement devices. The aim of the study was to evaluate the association between the implant stability and peri-implant vertical defect by using the new wireless RF analyser. Micro-textured rough-surfaced implants with diameters of 3.7 and 4.8 mm and with a length of 12 mm were used. The peak insertion torque was recorded with the help of the torque control system only during the implant placement. The peri-implant defects were created in millimetre increments ranging between 0 and 5 mm to the same extent on all implants. The RF analysis values were measured by using the RF analyser. Significant correlation was found between insertion torque (44.3 +/- 3 N cm) and implant stability quotient (ISQ) (all implants: r = 0.76, 3.7 mm diameter: r = 0.65, 4.8 mm diameter: r = 0.80). For 3.7 x 12-mm(2) implants, the mean ISQ values were 72.6 +/- 2.4, 69.8 +/- 2, 67.2 +/- 1.8, 64.3 +/- 1.9, 61.2 +/- 2 and 57.2 +/- 2.5 when peri-implant vertical defects were 0, 1, 2, 3, 4 and 5 mm; and the corresponding values were 76.5 +/- 2.2, 74.5 +/- 2.2, 72.3 +/- 2, 70 +/- 1.9, 67 +/- 1.9 and 63.4 +/- 2.3, respectively, for 4.8 x 12-mm(2) implants. All values were significantly different when compared with each other. The wireless RF analyser seems to be a suitable and reliable device to determine the implant stability. Peri-implant bone loss simulated by using acrylic models may result with a decrease in ISQ values for osseo-integrated implants measured by the RF analyser.