Mean Implant Stability Quotient Values Research Articles

Relationship between implant stability measured by resonance frequency analysis (RFA) and bone loss during early healing period

The aim of this study was to monitor the changes in the stability-related bone loss during the early healing period. A total of 43 implants were installed in 19 patients, and their stability was measured by resonance frequency analysis (RFA) at the time of surgery and once per week for 12 weeks. A total of 32 implants had radiographs taken at the placement of implant and 4, 8, and 12 weeks postoperatively. The data for gender, bone density, different surgery protocols, and bone loss around implant were analyzed. The mean implant stability quotient values were not changed during the healing period. The marginal bone losses at 12 weeks were 1.28 +/- 0.51 mm and 1.32 +/- 0.57 mm on the mesial and distal sides, respectively. The implant stability in normal and hard bone density did not change with time, and there was no correlation between the marginal bone loss and the change of implant stability.

Comparison of initial implant stability measured by Resonance Frequency Analysis between different implant systems

Purpose: The objective of this study was to compare initial implant stability measured by RFA between different implant systems during the initial healing period. Material and Methods: Fifty-four patients (36 males/18 females) who had been treated at the Department of Periodontology, Chonbuk National University Dental Hospital during the period between January and November in 2007 were included in the study. The mean age of the subjects was 49 years old (18 to 77). A total of 104 implants (Type A: 3i Osseotite ® , Type B: Replace ® select, Type C: ITI implant) were placed following the manufacturer's standard surgical protocols. Implant stability quotient (ISQ) readings were obtained for each implant at the time of surgery, 2-, and 4-month postoperatively. Result: No implant was failed during the observation period. At the baseline, the difference between mean ISQ values of 3 implant systems was statistically significant (p<0.05). However, at 2-, and 4-month following implant surgery, no significant difference was observed between ISQ values of the implant systems. In the same implant, the ISQ values of Type B and C implants increased (p<0.05), but those of Type A implants decreased during the 2-month healing period. The mean ISQ values of Type B and C implants showed a increasing tendency, while those of Type A implants were stable for the 4-month follow-up period. Conclusion: Within limits of this study, it can be concluded that implant design and surface topography of implant might influence the ISQ value and changing pattern during the initial healing period. (J Korean Acad Periodontol 2008;38:529-534)

Correlation between Implant Stability Quotient (ISQ) with Clinical and Histological Aspects of Dental Implants Removed for Mobility

Dental implants are a successful treatment modality for missing teeth; however, failures do occur. These failures can occur early in the healing process after primary stability has been achieved at the time of implant placement, or after initial bone remodeling and new bone growth have taken place. The ability to detect implants that are failing or will fail is still not possible. The aim of the present study is to see if correlations exist between RFA values and histologic and histochemical evaluation of the human retrieved implants for failure. In a 5 year period, 37 root form implants were retrieved because of mobility and underwent histological examination. Thin ground sections were obtained from each implant. All the implants had been removed with a 5 mm trephine. In all cases a peri-implant radiolucency was present. Before implant retrieval, the implant stability was evaluated with Osstell (Integration Diagnostics AB, Gothenburg, Sweden). All the implants were not osseointegrated clinically and mobility was present. Radiographically, bone loss was observed around the implants and the mean ISQ values was 37 (+/- 2.7). A scarce inflammatory cell infiltrate was present in the connective tissue of some specimens. In about 10 percent of specimens, the epithelium tended to surround the total perimeter of the implant. These data suggest that implants with an ISQ<40 are irretrievably lost and there is no possibility to save them. A statistically significant correlation was found between an ISQ<36 and irretrievably failed implants.

Ninety percent success in palatal implants loaded 1 week after placement: a clinical evaluation by resonance frequency analysis

To investigate the behaviour of early loaded palatal implants when observed with resonance frequency analysis (RFA). Twenty patients (seven males and 13 females, mean age 26.4 years) received one palatal implant each (length: 4 mm, diameter: 3.3 mm; Orthosystem) for maximum orthodontic anchorage. The implants' stability was observed by RFA. Measurements were carried out at the time of surgery, after first orthodontic loading and subsequently once a week over a period of 12 weeks. Two palatal implants were lost. The other 18 remained stable. The average period from insertion to first loading was 6.7+/-0.8 days. The mean orthodontic force applied was 272.2+/-73.2 cN. The implant stability quotient (ISQ) value at the time of surgery averaged 69.4+/-3.9. The mean ISQ value 6.7 days after insertion was 69.8+/-3.6. Twelve weeks post-surgery the mean ISQ value was 69.8+/-3.5. A statistically significant decrease in stability was observed after 2 and 3 weeks post-surgery (P=0.005 and 0.04). The behaviour of early loaded palatal implants showed an initial decrease of the ISQ values. From 6 weeks post-surgery onward the ISQ values increased. Within the limitations of this study, the results suggest that the healing time of palatal implants reported in the literature (12 weeks) should be discussed. An orthodontic loading of palatal implants 6 weeks post-surgery with a force up to 400 cN seems to be justified. Yet further investigations are necessary to evaluate the behaviour of early loaded palatal implants considering observation periods of over 12 weeks.

Immediate Loading Versus Immediate Provisionalization of Maxillary Single-Tooth Replacements: A Prospective Randomized Study With BioComp Implants

The aim of this prospective randomized study was to evaluate the clinical outcome of immediately loaded solid plasma sprayed (TPS) BioComp (BioComp Industries BV, Vught, The Netherlands) implants versus immediate provisionalized but non-loaded BioComp implants in the anterior and premolar region of the maxilla. Forty-eight patients (31 females and 17 males) with a mean age of 42.3+/-13.1 years (range 19 to 78 years) were included in the study. Fifty threaded TPS implants were placed and provisionalized within 24 hours after surgery. The patients were randomly assigned to 2 groups. In the immediate loaded (IL) group (n=24) the occlusion of the provisional was designed with normal contacts in centric relation and at lateral excursions, while in the non-immediate loaded (IP) group (n=24) the provisional restoration was adjusted to clear all occlusal contacts or contacts at lateral excursions. Patients were instructed to eat a soft diet and to avoid placing food in the area of the provisional crown during the first 6 weeks. Regular clinical and radiographic controls were performed and the survival rate and implant stability quotient (ISQ) values were evaluated at delivery of the definitive restoration at 6 months. At 1 year, radiographic coronal bone defects and gingival esthetics between the 2 groups were assessed. Of the IL group, 2 fixtures were lost, while 3 implants were lost in the IP group. The failing implants showed increasing mobility at 2 to 3 weeks after insertion, and were removed. The remaining 45 implants were stable at every subsequent follow-up examination, and 6 months after implant placement, ISQ values were measured. The mean ISQ value in the IL group was 63.7+/-5.8 versus 63.2+/-4.3 for the IP group (P=.78). The mean mesial marginal bone loss after 12 months in the IL group was 0.27+/-0.2 mm versus 0.28+/-0.22 mm in the IP group (P=.9). The mean distal marginal bone loss after 12 months in the IL group was 0.19+/-0.15 mm versus 0.2+/-0.11 mm in the IP group (P=.87). All implants of the IL group had an ideal gingival buccal margin, versus 91% of the IP group. Full regeneration of the mesial interdental papilla was observed in 70% of the IL group versus 91% of the IP group, while full regeneration of the distal papilla was observed in 91% of both the IL and IP implants. No significant differences in ISQ mean values in radiographic bone loss and gingival esthetics were found between immediate non-loaded provisionalization and immediately loaded BioComp implants in the maxilla.

Bone Reformation with Sinus Membrane Elevation: A New Surgical Technique for Maxillary Sinus Floor Augmentation

Various maxillary sinus floor augmentation techniques using bone grafts and bone substitutes are frequently used to enable placement of dental implants in the posterior maxilla. A previous case report demonstrated the possibility of promoting bone formation in the sinus by lifting the membrane without using a grafting material. However, the predictability of the technique is not known. The aim of this study was to investigate whether sinus membrane elevation and the simultaneous insertion of titanium implants without additional grafting material constitute a valid technique for bone augmentation of the maxillary sinus floor. The study group comprised 10 patients in whom a total of 12 maxillary sinus floor augmentations were performed. A replaceable bone window was prepared in the lateral sinus wall with a reciprocating saw. The sinus membrane was dissected, elevated superiorly, and sutured to the sinus wall to create and maintain a compartment for blood clot formation. One to three dental implants were inserted through the residual bone and protruded at least 5 mm into the maxillary sinus. The bone window was replaced and secured with the overlying mucosa. Bone height was measured directly at each implant site at the time of insertion. Resonance frequency analysis (RFA) was performed on each implant at the time of initial placement, at abutment surgery, and after 12 months of functional loading. Computed tomography (CT) was performed in the immediate postoperative period and 6 months later, prior to exposure of the implants. A total of 19 implants (Brånemark System, TiUnite, Nobel Biocare AB, Gothenburg, Sweden) in lengths of 10 to 15 mm were placed, with an average residual bone height of 7 mm (range, 4-10 mm). All implants remained clinically stable during the study period. Comparisons of pre- and postoperative CT radiography clearly demonstrated new bone formation within the compartment created by the sinus membrane elevation procedure. RFA measurements showed mean implant stability quotient values of 65, 66, and 64 at placement, at abutment connection, and after 12 months of loading, respectively. The study showed that there is great potential for healing and bone formation in the maxillary sinus without the use of additional bone grafts or bone substitutes. The secluded compartment created by the elevated sinus membrane, implants, and replaceable bone window allowed bone formation according to the principle of guided tissue regeneration. The precise mechanisms are not known, and further histologic studies are needed. Sinus membrane elevation without the use of additional graft material was found to be a predictable technique for bone augmentation of the maxillary sinus floor.