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Concept: Implant stability quotient


Background: There are a few prospective studies reporting on new implant systems. When a new implant is brought to market, prospective trials should be carried out to determine the predictability of that system. Purpose: This prospective study evaluates implant survival, Resonance Frequency Analysis (RFA), and crestal bone level changes for a new implant system (Neoss System, Bimodal surface, Neoss Ltd, Harrogate, UK). Materials and Methods: Seventy-six patients, 38 females (age ranging from 23 to 57 years) and 38 males (ranging in age from 17 to 85 years) received 100 Neoss implants. Patients were consecutively enrolled in the study if they were missing one or more teeth in either arch, or a single tooth was scheduled for removal and immediate implant replacement. Evaluated implants were 4, 4.5, or 5 mm wide and were 7, 9, 11, 13, or 15 mm long. A one-stage approach was followed. At first stage and prior to healing abutment placement RFA measurements were taken. Measurements were retaken at second stage. Fifty-one implants were placed for restoration of single missing teeth and 49 were for short span implant bridges. Results: The cumulative survival rate at 1- to 2-year interval was 93%. Average initial RFA measurement for all implants was 72.06, while the average final score was 72.58. These changes were not statistically significant. Changes in RFA scores for maxillary implants were insignificant. Forty-two paired mandibular RFA measurements were evaluated. Initial and final mean mandibular RAF measurements were 73.65 (SD 9.203) and 77.186 (SD 6.177), respectively. These changes were statistically significant (p = .02). Sixty-four paired radiographs were available for evaluation. Between examinations, there was an average -0.6 mm of bone loss, which was statistically significant (p = .03). On average, 4.0-mm-wide implants lost 0.1 mm of bone when compared with 5-mm-wide implants. These differences were insignificant (p = .86). Bone loss was adjusted for implant length, and tooth position and there were small, but clinically insignificant changes. Five-millimeter-wide implants lose 0.2 mm more than 4.0-mm-wide implants (p = .7). Maxillary incisors lose the least amount of bone 0.152 (p = .33). Conclusions: The implants tested in this study had initially high RAF readings, indicating good primary stability. RFA readings for implants placed in the mandible improved from baseline and the changes were statistically significant. Marginal bone levels revealed clinically insignificant bone loss from implant installation to second stage. Loss of seven implants with initially high RFA readings is surprising.

Concepts: Statistics, Teeth, Dental implant, Dentistry, Resonance, Resonance Frequency Analysis, Implant stability quotient, Electrical resonance


Background: 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. Purpose: 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. Materials and Methods: 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). Results: 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. Conclusions: 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.

Concepts: Male, Dental implant, Dentistry, Resonance, Resonance Frequency Analysis, Implant stability quotient


Many surgical procedures use metal implants in bone. The clinical results depend on the strength of the bone holding these implants. Our objective was to show that a drug released from the implant surface can improve parameters reflecting the quality or amount of this bone. Sixteen patients received paired dental titanium implants in the maxilla, in a randomized, double-blinded fashion. One implant in each pair was coated with a thin fibrinogen layer containing 2 bisphosphonates. The other implant was untreated. Fixation was evaluated by measurement of resonance frequency (implant stability quotient; ISQ) serving as a proxy for stiffness of the implant-bone construct. Increase in ISQ at 6months of follow-up was the primary variable. None of the patients had any complications. The resonance frequency increased 6.9 ISQ units more for the coated implants (p=0.0001; Cohen’s d=1.3). The average difference in increase in ISQ, and the effect size, suggested a clinically relevant improvement. X-ray showed less bone resorption at the margin of the implant both at 2months (p=0.012) and at 6months (p=0.012). In conclusion, a thin, bisphosphonate-eluting fibrinogen coating might improve the fixation of metal implants in human bone. This might lead to new possibilities for orthopedic surgery in osteoporotic bone and for dental implants.

Concepts: Osteoporosis, Improve, Surgery, Dental implant, Titanium, Dentistry, Resonance Frequency Analysis, Implant stability quotient


BACKGROUND: New implant designs are continuously introduced to the market. It is important to evaluate and report on their clinical performance when used in everyday practice. PURPOSE: The aim of the present study was to evaluate the clinical performance of a novel hydrophilic dental implant for 1 year. MATERIALS AND METHODS: A total of 49 patients previously treated with 102 hydrophilic dental implants (Neoss Proactive, Neoss Ltd, Harrogate, UK) were retrospectively evaluated with regard to survival rate and marginal bone loss. Fifty-four implants were installed in maxillae and 48 in mandibles to replace single teeth (n = 21), to support partial bridges (n = 26), total maxillary bridges (n = 2), or mandibular overdentures (n = 2). The majority of patients (n = 37) had implants placed in healed sites without any adjunctive procedures. In 12 patients, implants were immediately placed in extraction sockets or in conjunction with maxillary sinus floor augmentation. All implant sites had been classified according to the Lekholm and Zarb index. Baseline and 1-year intraoral radiographs were used to calculate marginal bone levels and bone loss. Implant stability quotient (ISQ) measurements had been taken at placement and after 3 to 4 months of healing RESULTS: The implants became rapidly covered with blood at the first contact. One implant was lost, giving a cumulative survival rate (CSR) of 99.0% after 1 year. The marginal bone loss amounted to 0.7 ± 0.6 mm with 3.5% of the implants showing more than 2 mm of bone loss and no implant more than 3 mm bone loss after 1 year. The primary stability was found to be 72.7 ± 7.5 ISQ, which slightly increased to 73.6 ± 7.2 ISQ (NS) after 3 to 4 months of healing. The stability was significantly higher in the mandible than in the maxilla at placement and after healing. CONCLUSION: In this limited clinical study, the use of a novel hydrophilic dental implant results in favorable short-term outcomes.

Concepts: Mandible, Implants, Dental implant, Titanium, Dentistry, Osseointegration, Implant stability quotient, Maxilla


The objective of this study was to evaluate the bone healing and peri-implant tissue response in heavy smokers receiving dental implants due to partially edentulous posterior mandibles. Forty-five ITI Straumann dental implants were placed into the partially edentulous posterior mandibles of 16 heavy smokers and 16 non-smokers. One implant in each patient was evaluated for implant stability after surgery and before loading, and for the modified plaque index (mPLI), modified sulcus bleeding index (mSBI), probing depth (PD), and marginal bone loss (MBL) after loading. Meanwhile, the osteogenic capability of jaw marrow samples collected from patients was evaluated via an in vitro mineralization test.For both groups, the implant stability quotient (ISQ) initially decreased from the initial ISQ achieved immediately after surgery and then increased starting from 2 weeks post-surgery. However, at 3, 4, 6, and 8 weeks post-surgery, the ISQ differed significantly between non-smokers and heavy smokers. All implants achieved osseointegration without complications at least by the end of 12th week post-surgery. At 6 or 12 months post-loading, the MBL and PD were significantly higher in heavy smokers than in non-smokers, whereas the mSBI and mPLI did not differ significantly between the two groups. The 1-year cumulative success rate of implants was 100% for both groups. Within the limitations of present clinical study (such as small sample size and short study duration), which applied the loading at 3 months post-operation, heavy smoking did not affect the cumulative survival rate of dental implants placed at the posterior mandible in male patients, but heavy smoking did negatively affect bone healing around dental implants by decreasing the healing speed. These results implied that it might be of importance to select the right time point to apply the implant loading for heavy smokers. In addition, heavy smoking promoted the loss of marginal bone and the further development of dental pockets. Further clinical studies with larger patient populations are warranted to confirm our findings over a longer study duration.

Concepts: Clinical trial, Sample size, Implants, Dental implant, Dentistry, Osseointegration, Jaw, Implant stability quotient


Characteristics of the implant surface may benefit osseointegration, and the knowledge of this process in diverse clinical situations may play a role in implant dentistry practice.

Concepts: Implants, Dental implant, Dentistry, Oral and maxillofacial surgery, Osseointegration, Resonance, Implant stability quotient


A current implant body surface was treated with “rough processing” by sandblasting and acid etching for the purposes of obtaining more reliable osseointegration and shortening the treatment period. Various reports have examined the healing period with the use of these implant bodies, but a consensus opinion has not yet been obtained. The purpose of this study is to evaluate the relationship between insertion torque (IT) and implant stability quotient (ISQ) at implant treatment using the current rough-surfaced implant. We evaluated the implant treatment sites with ISQ values, IT values, and voxel values.

Concepts: Implants, Prosthetics, Dental implant, Dentistry, Osseointegration, Implant stability quotient, Body, Per-Ingvar Brånemark


The use of two particulate bone graft substitute materials in experimental narrow marginal peri-implant bone defects was investigated with respect to early bone healing and implant stability. Porous titanium granules, oxidized white porous titanium granules (WPTG), and demineralized bovine bone mineral (DBBM) were characterized in vitro, after which the two latter materials were tested in experimental peri-implant bone defects in six minipigs, with empty defects as control. After mandibular premolar extraction, the top 5mm of the alveoli were widened to 6mm in diameter, followed by the placement of six implants, three on each side, in each pig. Six weeks of healing was allowed. The WPTG showed better mechanical properties. No significant differences in resonance frequency analysis were found directly after compacting or healing, and similar quantities of defect bone formation were observed on micro-computed tomography for all groups. Histomorphometric analysis demonstrated a more coronal bone-to-implant contact in the DBBM group, which also displayed more defect bone fill as compared to the WPTG group. The better mechanical properties observed for WPTG appear of negligible relevance for the early stability and osseointegration of implants.

Concepts: Dental implant, Titanium, Dentistry, Osseointegration, Resonance, Resonance Frequency Analysis, Implant stability quotient, Balance wheel


Numerous studies indicate implants placed immediately after extraction or with minimally invasive procedures have excellent long-term success and survival rates. There is general agreement that implants must be stable after implant placement. This study evaluated implant stability changes from the time of implant placement to second stage (prior to restoration). Resonance frequency analysis (RFA) was determined for two commercially available units (Osstell, Osstell USA, Columbia, MD and Penguin, Penguin Integration Diagnostics, Sweden). The unit of measurement was the implant stability quotient (ISQ).

Concepts: Dental implant, Units of measurement, Dentistry, International System of Units, Resonance, Radio, Resonance Frequency Analysis, Implant stability quotient


This case report aimed to describe the effects of leukocyte and platelet-rich fibrin (L-PRF) associated with deproteinized bovine bone mineral (DBBM) and absorbable collagen membrane (CM) on bone regeneration in maxillary sinus augmentation. A 59-year-old male patient was referred to the Department of Periodontology for implant rehabilitation of his edentulous upper jaw. The treatment plan involved maxillary sinus augmentation followed by implants installation. A split-mouth design was employed, in which the right maxillary sinus was filled using L-PRF, DBBM, and CM; the left side was filled with DBBM and CM. After four and eight-months post-operatively, two dental implants were installed in each of the right and left maxillary sinus, respectively. Cone-beam computed tomography (CBCT) was taken before and after sinus augmentation for evaluation of tridimensional bone volume alterations. Bone biopsies were harvested from the implant sites for histomorphometric evaluation. Resonance frequency analysis was employed immediately after implant placement and before prosthetic rehabilitation for evaluation of implant stability. Implants were loaded 10-months after sinus augmentation. CBCT analysis showed a higher resorption rate in the right side of the maxillary sinus (L-PRF + DBBM) compared to the left side (22.25% and 8,95%, respectively). Implant stability quotient were above 68 in all time-points for both groups. Histomorphometric analysis showed highly amount of newly formed bone when L-PRF was used compared with DBBM alone (2118102 and 975535 mm3, respectively). Taken together, both techniques were effective for maxillary sinus augmentation, however the addition of L-PRF to the graft allowed early implant placement and accelerated bone healing in the conditions studied.

Concepts: Dental implant, Maxillary sinus, Dentistry, Resonance, Resonance Frequency Analysis, Implant stability quotient, Maxilla, Sinus augmentation