The relationship between implant stability quotient values and implant insertion variables: a clinical study

Pre-implantation teriparatide administration improves initial implant stability and accelerates the osseointegration process in osteoporotic rats

PURPOSE

Osteoporotic individuals who have dental implants usually require a prolonged healing time for osseointegration due to the shortage of bone mass and the lack of initial stability. Although studies have shown that intermittent teriparatide administration can promote osseointegration, there is little data to support the idea that pre-implantation administration is necessary and beneficial.

METHODS

Sixty-four titanium implants were placed in the bilateral proximal tibial metaphysis in 32 female SD rats. Bilateral ovariectomy (OVX) was used to induce osteoporosis. Four major groups (n = 8) were created: PRE (OVX + pre-implantation teriparatide administration), POST (OVX + post-implantation administration), OP (OVX + normal saline (NS)) and SHAM (sham rats + NS). Half of rats (n = 4) in each group were euthanized respectively at 4 weeks or 8 weeks after implantation surgery, and four major groups were divided into eight subgroups (PRE4 to SHAM8). Tibiae were collected for micro-CT morphometry, biomechanical test and undecalcified sections analysis.

RESULTS

Compared to OP group, rats in PRE and SHAM groups had a higher value of insertion torque (p < 0.05). The micro-CT analysis, biomechanical test, and histological data showed that peri-implant trabecular growth, implants fixation and bone-implant contact (BIC) were increased after 4 or 8 weeks of teriparatide treatment (p < 0.05). There was no statistically difference in those parameters between PRE4 and POST8 subgroups (p > 0.05).

CONCLUSIONS

In osteoporotic rats, post-implantation administration of teriparatide enhanced peri-implant bone formation and this effect was stronger as the medicine was taken longer. Pre-implantation teriparatide treatment improved primary implant stability and accelerated the osseointegration process.

Effect of Implant Macro-Design and Magnetodynamic Surgical Preparation on Primary Implant Stability: An In Vitro Investigation

BACKGROUND

Macro-geometry and surgical implant site preparation are two of the main factors influencing implant stability and potentially determining loading protocol. The purpose of this study was to assess the initial stability of various implant macro-designs using both magnetodynamic and traditional osteotomy techniques in low-density bone. The parameters examined included peak insertion torque (PIT), implant stability quotient (ISQ), and peak removal torque (PRT).

METHODS

Four groups of 34 implants each were identified in accordance with the surgery and implant shape: T5 group (Five implant and osteotomy using drills); M5 group (Five implant and magnetodynamic osteotomy using Magnetic Mallet); TT group (TiSmart implant and osteotomy with drills); and MT group (TiSmart implant and magnetodynamic osteotomy). Every implant was placed into a low-density bone animal model and scanned using CBCT. The PIT and PRT were digitally measured in Newton-centimeters (Ncm) using a torque gauge device. The ISQ was analyzed by conducting resonance frequency analysis.

RESULTS

The PIT values were 25.04 ± 4.4 Ncm for T5, 30.62 ± 3.81 Ncm for M5, 30 ± 3.74 Ncm for TT, and 32.05 ± 3.55 Ncm for MT. The average ISQ values were 68.11 ± 3.86 for T5, 71.41 ± 3.69 for M5, 70.88 ± 3.08 for TT, and 73 ± 3.5 for MT. The PRT values were 16.47 ± 4.56 Ncm for T5, 26.02 ± 4.03 Ncm for M5, 23.91 ± 3.28 Ncm for TT, and 26.93 ± 3.96 Ncm for MT. Based on our data analysis using a t-test with α = 0.05, significant differences in PIT were observed between TT and T5 (p < 0.0001), M5 and T5 (p < 0.0001), and MT and TT (p = 0.02). Significant differences in the ISQ were found between TT and T5 (p = 0.001), M5 and T5 (p < 0.001), and MT and TT (p = 0.01). The PRT also exhibited significant differences between TT and T5, M5 and T5, and MT and TT (p < 0.0001).

CONCLUSION

Our data showed favorable primary implant stability (PS) values for both implant macro-geometries. Furthermore, the magnetodynamic preparation technique appears to be more effective in achieving higher PS values in low-density bone.

Resonance Frequency Analysis Mapping During Implant Healing Using a Nanostructured Hydroxyapatite Surface

Aim

Stability measured by resonance frequency analysis (RFA) is an important factor to be considered in the success of dental implant treatments, which can be evaluated from the implant stability quotient (ISQ). The aim of the present case series was to map the RFA during healing of implants with nanostructured hydroxyapatite surface to describe the behavior of ISQ values related to individual factors.

Materials and Methods

Twenty-three implants were placed in eight patients by conventional surgical protocol, and ISQ values were monitored from the day of implant placement until week 20. To obtain the ISQ values, an Osstell device was used and the placed implants were grouped in proportional amounts to describe the ISQ behavior considering the length (≤10 or >10 mm), the diameter (3.5 or 4.3 mm), the insertion torque (<40 N-cm or ≥40 N-cm), and the placement area (maxilla or mandible).

Results

All the implants assessed decreased their values in the first 3 weeks after placement. Subsequently, the ISQ values increased by amounts similar to those obtained at the time of the placement and even more. Implants with length >10 mm, diameter 4.3 mm, and insertion torque ≥40 N-cm showed the highest ISQ values.

Conclusions

A decrease in the ISQ values of dental implants with nanostructured hydroxyapatite surface was evidenced between weeks 2 and 3 considering length, diameter, insertion torque, and maxillary or mandibular placement site.

The Effect of Laser Micro Grooved Platform Switched Implants and Abutments on Early Crestal Bone Levels and Peri-Implant Soft Tissues Post 1 Year Loading among Diabetic Patients-A Controlled Clinical Trial

Background and Objectives: The study aimed to compare the mean crestal bone level (CBL) and peri-implant soft tissue parameters in laser micro-grooved (LMG) platform switched implants and abutments (I&A) post 1 year of functional loading among non-diabetic and type II diabetic individuals. Materials and methods: Patients with an edentulous site having minimum bone height and width of ≥13 mm and ≥6 mm, respectively, were divided into two groups: (i) Non-diabetic-8 (control) and (ii) diabetic-8 (test). LMG Implants were placed and loaded immediately with a provisional prosthesis. Mean crestal bone level (MCBL) was evaluated radiographically at baseline and at 1 year. Peri-implant attachment level (PIAL) and relative position of the gingival margin (R-PGM) were recorded. Implant stability quotient (ISQ) level and implant survival rate (ISR) were evaluated at 1 year. Results: Early MCBL within the groups 1 year postloading was similar both mesially and distally (control-0.00 to 0.16 mm and 0.00 to 0.17 mm, respectively; test-0.00 to 0.21 mm and 0.00 to 0.22 mm, respectively) with statistical significance (p ≤ 0.003, p ≤ 0.001 and p ≤ 0.001, p ≤ 0.001, respectively). However, intergroup comparison showed no significant difference statistically in the MCBL in 1 year post functional loading. The peri-implant soft tissue parameters showed no significant difference between the groups. ISQ level between both groups did not reveal any significant changes (p ≤ 0.92), and ISR was 100%. Conclusions: LMG Implants resulted in minimal and comparable early crestal bone loss and soft tissue changes post 1 year of functional loading in moderately controlled diabetic and non-diabetic individuals, suggesting that this could be a reliable system for use in systemically compromised individuals.

Hybrid Funnel Technique: A Novel Approach for Implant Site Preparation: A Pilot Study

(1) Background: Different techniques and tools have been developed for implant site preparation. In this clinical scenario, Hybrid Funnel Technique (HFT), a novel osteotomy procedure, has been proposed. (2) Aim: The aim of this retrospective observational study was to consider the different responses to compression of the histological bony compartments (cancellus and cortical). HFT involves the use of multiple drills for the cortical layer preparation and of an osteotome for the osteocompaction of the cancellous bone. (3) Materials and Methods: Following computer-supported implant planning and guided surgery, 10 osteotomies with HFT were performed and 10 implants with the same length and diameter were placed in seven healthy and no daily smoking patients. Periapical X-ray and intraoral photographs were performed at baseline and after 12 months of follow-up to evaluate marginal bone level (MBL) changes and aesthetic results obtained from implant prosthetic rehabilitation. (4) Results: At 1 year of follow-up, 100% of the implants were successfully integrated, MBL change mean value was 0.17 mm ± 0.21. No differences in terms of MBL were noted between thin and thick biotypes. Pink esthetic score (PES) and white esthetic score (WES), assessed one year after definitive restoration placement, were 7.5 ± 2.3 and 8.5 ± 1.1, respectively. (5) Conclusions: Based on the findings of this preliminary clinical study, HFT has led to stability of peri-implant tissues and could represent a reliable technique for surgical preparation of the implant site.

The Effects of Insertion Approach on the Stability of Dental Implants

Dental implant surgery involves the insertion of a dental implant into the alveolar bone; the success of the surgery depends on the initial stability of the implant. The objective of this study was to examine the effects of dental implant insertion approaches in clinical surgery and in accordance with the standards of American Society for Testing and Materials on initial implant stability. Three insertion approaches were used for dental implant placement (Branemark Systems NobelSpeedy Groovy, Nobel Biocare AB, Gothenburg, Sweden) in two types of artificial bone—good bone (GB) and poor bone (PB). The three insertion approaches were as follows: (1) continuous rotation insertion (CRI): using a torque testing machine to continuously screw in an implant to completion and (2 and 3) intermittent rotation insertion (IRI)_90 and IRI_80: using CRI to bury an implant to 90% and 80% of its full length followed by IRI to complete the implantation, respectively. The maximum insertion torque value (ITV), periotest value (PTV), and implant stability quotient (ISQ) were measured and compared. The results indicated that bone quality and insertion approach both affected implant stability. Insertion approaches affected all three implant stability indicators differently in the GB and PB groups (p = 0.008). In GB groups, the insertion approach primarily affected ITV, whereas in PB groups, it primarily affected PTV. The effect of the insertion approach was less apparent for ISQ. Overall, in both the GB and PB groups, the implant stability for IRI_80 was greater than that for IRI_90, and the implant stability for IRI_90 was greater than that for CRI. Future in vitro studies should adopt an insertion approach that complies with the clinical practice for dental implant surgery. Dentists should adjust the timing for IRI in dental implant surgery to achieve greater initial dental implant stability.

Stability of Dental Implants and Thickness of Cortical Bone: Clinical Research and Future Perspectives. A Systematic Review

Dental surgery implantation has become increasingly important among procedures that aim to rehabilitate edentulous patients to restore esthetics and the mastication ability. The optimal stability of dental implants is correlated primarily to the quality and quantity of bone. This systematic literature review describes clinical research focusing on the correlation between cortical bone thickness and primary/secondary stability of dental fixtures. To predict successful outcome of prosthetic treatment, quantification of bone density at the osteotomy site is, in general, taken into account, with little attention being paid to assessment of the thickness of cortical bone. Nevertheless, local variations in bone structure (including cortical thickness) could explain differences in clinical practice with regard to implantation success, marginal bone resorption or anchorage loss. Current knowledge is preliminarily detailed, while tentatively identifying which inconclusive or unexplored aspects merit further investigation.

Comparison of Implant Stability between Regenerated and Non-Regenerated Bone. A Prospective Cohort Study

Implant stability is one of the main indicators of successful osseointegration. Although it has been measured in numerous studies, there has been little research on implant stability in regenerated bone. The study compares primary and secondary stability between implants placed in regenerated versus native bone and evaluates the influence of bone quality on the results. Sixty implants were placed in 31 patients: 30 implants inserted in native bone (non-regenerated) after a healing period of at least 6 months post-exodontia and 30 inserted in regenerated bone at 6 months after grafting with xenograft. Resonance frequency analysis (RFA) was used to obtain implant stability quotient (ISQ) values at baseline (implant placement), 8 weeks, and 12 weeks. Statistically significant differences were found between implants placed in regenerated bone and those placed in native bone at all measurement time points (p < 0.05). ISQ values were significantly influenced by bone quality at baseline (p < 0.05) but not at 8 or 12 weeks. Greater stability was obtained in implants placed in native bone; however, those placed in regenerated bone showed adequate primary and secondary stability for prosthetic loading. Bone quality influences the primary but not secondary stability of the implants in both native and regenerated bone.

Relation Between Insertion Torque and Implant Stability Quotient: A Clinical Study

Objectives This study aimed to assess the relation between the insertion torque and implant stability quotient (ISQ recorded immediately and 6 months after implant placement).

Materials and Methods Twenty-five patients over the age of 18 years were selected for this study. One implant was placed per patient after tooth extraction. All implants had the same size (11.5 × 3.75 mm) and brand (Hexagonal Morse cone, DSP Biomedical). The insertion torque (Ncm) and resonance frequency analysis (ISQ value) (Osstell Mentor) were used to assess the primary stability (on the day of surgery). After 6 months, resonance frequency analysis was used to assess the secondary stability of each implant.

Statistical Analysis The insertion torque data were correlated with ISQ measurements by using Pearson’s correlation. The significance level was 5%.

Results There was a positive correlation between insertion torque and initial ISQ (correlation: 0.457; p = 0.022); however, no correlation was found between insertion torque and final ISQ ( p = 0.308).

Conclusion The present study demonstrated that there is a positive correlation between the insertion torque and the initial ISQ. Therefore, the higher the insertion torque, the higher the initial ISQ (and vice versa).

The clinical significance of implant stability quotient (ISQ) measurements: A literature review

Implant stability quotients (ISQ values) are obtained in dental clinical practice on a non-invasive basis by resonance frequency measurement rapidly after surgical placement of implants. The ISQ-values are used as indicator for mechanical implant stability, and are believed to have predictive power for clinical outcome. It is the aim of this review to provide a synopsis of all factors described in the literature that influence ISQ measurements by performing an exhaustive literature review; moreover, this review aims at elucidating the key factors relevant for a rapid clinical predictive assessment. We searched systematically and exhaustively all major databases for publications relating to ISQ measurement methodology and for ISQ-influencing factor analyses. The reports identified were ordered in experimental (preclinical) studies and in clinical publications. We were able to identify 13 basic factors influencing ISQ-measurements. Among these, local bone quality, playing a key role in such measurements, was subdivided in four specific subfactors; thus a total of 17 individual factors was identified and reported to influence ISQ-measurements. A comprehensive list of these factors is provided in Table-form. A critical analysis points out that only 6 of these factors are of a sound predictive power useful for a rapid clinical assessment; and only two of these factors appear to have a well-documented scientific basis.

Implant Diameter, Length, and the Insertion Torque/Depth Integral: A Study Using Polyurethane Foam Blocks

The amount of energy necessary to place an implant in its seat, described as the integral of the torque-depth curve at insertion (I), has been validated as a reliable measure of primary stability. This study aimed to investigate whether (I) may detect the variations in primary stability caused by changes in the implant length or diameter better than the insertion torque (IT). Cylindric implants featuring a double-etched, sandblasted surface with different diameters or lengths were placed into monolithic polyurethane foam blocks with different densities that mimicked human bone. (I)-, (I)*-, IT-, IT*-diameter and -length plots ((I)* and IT* were the derived values corrected for undersizing) were drawn and the relation between (I), (I)*, IT, and IT* and the fixture diameter or length was investigated with correlation analysis. (I)* and IT* correlated better than (I) and IT with the fixture diameter; (I), (I)*, IT, and IT* correlated equally well with the fixture length. In all cases, the slopes of the lines best fitting the experimental data were greater for (I) or (I)* than IT or IT*, respectively. (I) or (I)* were better detectors than IT or IT* of the changes in primary stability that can be achieved by increasing the fixture diameter or length.

Influence of cortical bone and implant design in the primary stability of dental implants measured by two different devices of resonance frequency analysis: An in vitro study

Background

This study aimed to evaluate the effect of the implant design and the presence of cortical bone in the primary stability, as well as analyze the differences between the stability measurements obtained by two different resonance frequency analysis (RFA) devices.

Material and Methods

A total of 80 Klockner implants of two different models [40 Essential Cone implants (group A) and 40 Vega implants (group B)] were used. The implants were placed in two polyurethane blocks that simulated the mechanical properties of the maxillary bone. One block featured a layer of cortical bone that was absent from the other block. The primary stability of all implants was measured by insertion torque and RFA using two different devices: Penguin RFA and Osstell IDX.

Results

Primary stability was superior in the cortical bone in both torque and RFA. In the block containing cortical bone, group A implants obtained a greater insertion torque than did group B. The insertion torque was lesser in the bone lacking cortex. Regarding the ISQ of the implants, group A presented higher values in the block with cortical bone, but the values were lower in the block without cortical bone. There were no significant differences between the values obtained from the Osstell IDX and Penguin RFA.

Conclusions

The presence of cortical bone positively influences the primary stability of dental implants. The design of the implant also has a statistically significant influence on implant primary stability, although the impact depends on whether there is coronal cerclage or not. There were no statistically significant differences in the implant stability measurements obtained by two different devices.

Key words:Implant stability, resonance frequency analysis, torque, osstell, penguin, cortical.

Repeatability of the resonance frequency analysis values in implants with a new technology

Background

Assess the reliability (by means of reproducibility and repeatability) of the PenguinRFA system, analyse the ISQ values of different implant types and correlate the ISQ with the insertion torque during the placement of the implant.

Material and Methods

120 rough surface implants were placed in bovine bone (type II and III). The implants were divided into groups, according to its design. Once the implants were in place, the exact insertion torque was registered. Then, primary stability was measured by means of the resonance frequency analysis with the PenguinRFA and the Osstell ISQ devices. In each implant two transducers of each device were used. Three measurements were obtained with each transducer.

Results

The mean ISQ (implant stability quotient) of the whole sample is 67,70 ± 5,51. The Intraclass Correlation Coefficient (ICC) is 0,933 and 0,944 for transducers 1 and 2 respectively. The reproducibility is 0,906. The mean insertion torque is 24,54 ± 8,96N. The correlation between the ISQ and the insertion torque is 0,507 p<0,000 (MultiPeg 1) and 0,468 p<0,000 (MultiPeg 2) for bone type II and 0,533 p<0,801 (MultiPeg 1) and 0,193 p<0,140 (MultiPeg 2) for bone type III.

Conclusions

The results of the present trial suggest that the PenguinRFA presents excellent reproducibility and repeatability, so it could be very useful in the monitoring of the stability of implants over time. Additionally, according to the results, the correlation between the IT and the RFA is low and there are no statistically significant differences in between implant types.

Key words:Implant stability, insertion torque, ISQ, osseointegration, implant-supported dental prostheses, immediate dental implant loading.

Bone Density and Implant Primary Stability. A Study on Equine Bone Blocks

Previous results on synthetic blocks mimicking bone indicate that bone density can be measured by the friction encountered by a rotating probe while it descends into bone, and that primary implant stability may be measured through the integral (I) of the torque–depth curve at implant insertion. This study aims to repeat those tests on collagen-preserving equine bone blocks as they better reproduce the mechanical properties of natural bone. Fifteen cancellous equine blocks had their density measured using a measuring probe. This was compared to their known physical density through linear regression analysis. Implant placement was carried out into six cancellous equine blocks and primary stability was measured using (I), as well as the insertion torque (IT), the implant stability quotient (ISQ), and the reverse torque (RT). The relation between (I), (IT), (ISQ), and (RT) was investigated by correlation analysis. Bone density measured using the probe correlated significantly with actual density, both with (r = 0.764) and without irrigation (r = 0.977). (I) correlated significantly with IT and RT under all irrigation conditions, and with ISQ only without irrigation (r = 0.886). The results suggest that the probe provides actual bone density measurements. They also indicate that (I) measures primary implant stability and is more sensitive to density variations than IT, RT, and ISQ. Results are consistent with those obtained on synthetic blocks but suggest that equine bone blocks may better reproduce the mechanical properties of human cancellous alveolar bone. This should be the subject of additional studies.

A Clinical and Radiographic Evaluation of Resonance Frequency Analysis of Sand Blasted Acid Etched (SAE) and Chemical Modified Sae Dental Implants

Aims and Objective:

Chemically modified and sandblasted acid-etched (SAE) mechanism leads to wettability of surfaces of dental implants which helps in osseointegration. The present study was conducted to determine the implant stability quotient (ISQ) of SAE and SAE chemically modified dental implants.

Materials and Methods:

The present study was conducted on 210 patients with 120 males and 90 females. Dental implants (Adin) with SAE (Group A) and SAE chemically modified (Group B) were inserted in patients. RFA was done immediately after implant insertion and after 1 week, 2 weeks, 6 weeks, 10 weeks, and 14 weeks. Results were statistically evaluated using SPSS Statistics for Windows, Version 21.0, IBM Corp., Armonk, NY, USA.

Results:

Maximum patients were in the age group of 25–35 years (males – 65, females – 48), followed by 35–45 years (males – 40, females – 32) and 45–55 years (males – 15, females – 10). Maximum dental implants were given in the right side (88) in males than females (56). On the left side, maximum implants were given in females (62) than males (56). Maximum RFA value of 86.2 and minimum value of 44.6 were observed in SAE dental implants (A). The maximum mean RFA value in chemically modified implants SAE (B) was 89.4 and minimum was 32.5.

Conclusion:

It was observed that surface treatment of dental implants shows higher implant–bone osseointegration. There is fastest osseointegration in implants with hydrophilic surfaces than those with SAE surfaces. ISQ was higher than 75 in both groups, which indicate higher implant stability.

Correlation between Implant Geometry, Bone Density, and the Insertion Torque/Depth Integral: A Study on Bovine Ribs

During insertion of dental implants, measurement of dynamic parameters such as the torque-depth curve integral or insertion energy might convey more information about primary stability than traditional static parameters such as the insertion or removal torque. However, the relationship between these dynamic parameters, bone density, and implant geometry is not well understood. The aim of this investigation was to compare static and dynamic implant stability measurements concerning three different implant designs when implants were inserted into bovine bone ribs and dynamic parameters were collected using an instantaneous torque measuring implant motor. Standard implant osteotomies were created in segments of bovine ribs. After measuring the bone density using the implant motor, 10 cylindrical, 10 hybrid tapered-cylindrical, and 10 modified cylindrical implants were placed, and their primary stability was assessed by measuring the torque–depth curve integral, along with insertion and removal torque. The relationship between these quantities, bone density, and implant geometry was investigated by means of regression and covariance analysis. The regression lines describing the relationship between the torque–depth integral and bone density differed significantly from those describing the relationship between insertion torque, removal torque, and bone density for all three designs. The torque–depth curve integral provides different information about immediate primary stability than insertion and removal torque and in certain clinical conditions might be more reliable than these static parameters for assessing implant primary stability. Further research should be carried out to investigate the findings of the present study.

Influence of cortical bone anchorage on the primary stability of dental implants

PURPOSE

This retrospective chart review study assessed patient records to determine implant insertion torque (IT) and implant stability quotient (ISQ) values during implant placement to evaluate the correlation with cortical bone anchorage (mono- or bicortical).

METHODS

Primary stability data (IT during implant placement surgery and ISQ values immediately after implant placement) and cone beam computed tomography of 33 patients (165 implants) were assessed. Patients were divided into the following groups: G1, implants with apical cortical bone contact; G2, implants with bicortical bone contact (apical and cervical regions); and G3, implants with cervical cortical bone contact.

RESULTS

Sixty-eight implants were excluded due to cortical bone contact on regions other than implant apical or cervical. Ninety-seven implants were therefore assessed for this study. No implant failure was found after a mean 70.42-month follow-up time. Implants with bicortical anchorage (G2) showed higher IT (64.1 Ncm) during implant placement and higher ISQ values (76) (p < 0.05). Monocortical implants (G1, apical, and G3, cervical) showed similar IT (G1 52.3 and G3 54.3) and ISQ values (G1 71.9 and G3 73) (p > 0.05). No correlation (Pearson correlation coefficient) was found between the two stability measurement devices for the different cortical bone anchorages that were analyzed (G1 0.190, G2 0.039, and G3 - 0.027) (p > 0.05).

CONCLUSIONS

Insertion torque values and implant stability quotients were influenced by cortical bone contact. No significant correlation was found between IT and ISQ values-higher insertion torque values do not necessarily lead to higher implant stability quotients.

The impact of photofunctionalized gold nanoparticles on osseointegration

OBJECTIVES

The aims of this study were to create a new surface topography using simulated body fluids (SBF) and Gold Nanoparticles (GNPs) and then to assess the influence of UV Photofunctionalization (PhF) on the osteogenic capacity of these surfaces.

MATERIALS AND METHODS

Titanium plates were divided into six groups All were acid etched with 67% Sulfuric acid, 4 were immersed in SBF and 2 of these were treated with 10 nm GNPs. Half of the TiO2 plates were photofunctionalized to be compared with the non-PhF ones. Rat's bone marrow stem cells were seeded into the plates and then CCK8 assay, cell viability assay, immunofluorescence, and Scanning electron microscopy (SEM) were done after 24 hours. Gene expression analysis was done using real time quantitative PCR (qPCR) one week later to check for the mRNA expression of Collagen-1, Osteopontin and Osteocalcin. Alkaline phosphatase (ALP) activity was assessed after 2 weeks of cell seeding.

RESULTS

Our new topography has shown remarkable osteogenic potential. The new surface was the most biocompatible, and the 10 nm GNPs did not show any cytotoxicity. There was a significant increase in bioactivity, enhanced gene expressions and ALP activity.

CONCLUSIONS

GNPs enhances osteogenic differentiation of stem cells and Photofunctionalizing GNPs highly increases this. We have further created a novel highly efficient topography which highly enhances the speed and extent of osseointegration. This may have great potential for improving treatment outcomes for implant, maxillofacial as well as orthopedic patients.

The insertion torque-depth curve integral as a measure of implant primary stability: An in vitro study on polyurethane foam blocks

STATEMENT OF PROBLEM

Recent research has shown that dynamic parameters correlate with insertion energy-that is, the total work needed to place an implant into its site-might convey more reliable information concerning immediate implant primary stability at insertion than the commonly used insertion torque (IT), the reverse torque (RT), or the implant stability quotient (ISQ). Yet knowledge on these dynamic parameters is still limited.

PURPOSE

The purpose of this in vitro study was to evaluate whether an energy-related parameter, the torque-depth curve integral (I), could be a reliable measure of primary stability. This was done by assessing if (I) measurement was operator-independent, by investigating its correlation with other known primary stability parameters (IT, RT, or ISQ) by quantifying the (I) average error and correlating (I), IT, RT, and ISQ variations with bone density.

MATERIAL AND METHODS

Five operators placed 200 implants in polyurethane foam blocks of different densities using a micromotor that calculated the (I) during implant placement. Primary implant stability was assessed by measuring the ISQ, IT, and RT. ANOVA tests were used to evaluate whether measurements were operator independent (P>.05 in all cases). A correlation analysis was performed between (I) and IT, ISQ, and RT. The (I) average error was calculated and compared with that of the other parameters by ANOVA. (I)-density, IT-density, ISQ-density, and RT-density plots were drawn, and their slopes were compared by ANCOVA.

RESULTS

The (I) measurements were operator independent and correlated with IT, ISQ, and RT. The average error of these parameters was not significantly different (P>.05 in all cases). The (I)-density, IT-density, ISQ-density, and RT-density curves were linear in the 0.16 to 0.49 g/cm³ range, with the (I)-density curves having a significantly greater slope than those regarding the other parameters (P≤.001 in all cases).

CONCLUSIONS

The torque-depth curve integral (I) provides a reliable assessment of primary stability and shows a greater sensitivity to density variations than other known primary stability parameters.

Resonance frequency analysis of dental implants placed at the posterior maxilla varying the surface treatment only: A randomized clinical trial

BACKGROUND

Chemical modifications of the dental implant surface that improve the wettability result in a faster and better osseointegration.

PURPOSE

The aim of this randomized clinical trial was to evaluate the implant stability quotient (ISQ) of implants with similar designs, treated with 2 surfaces, sandblasted acid-etched (SAE) and hydrophilic SAE, within the initial 16 weeks of healing.

MATERIAL AND METHODS

A total of 64 implants (32 SAE-control group and 32 modified SAE-test group) with the same design, length, and diameter (conical and compressive, 4.3 × 10 mm) were inserted into the posterior maxillae of 21 patients partially edentulous. The ISQ values were collected at post-surgery (T0), 1 week (T1), 2 weeks (T2), 3 weeks (T3), 5 weeks (T4), 8 weeks (T5), 12 weeks (T6), and 16 weeks (T7).

RESULTS

None of the implants failed. Test group presented ISQ values higher than the control group (ANOVA-P < .01) from T5 to T7. When comparing groups regarding the amount of time required to achieve ISQ ≥ 70 as a reference, there was a statistically significant difference (cox regression-P < .01), and a hazard ratio of 2.24 (CI 1.62-3.11). At the 1-year follow-up, there was a drop out of 1 patient, and 2 implants were no longer evaluated. Survival rate for both groups was 100% at the 1-year follow-up.

CONCLUSIONS

The current study suggests that implants with hydrophilic surface (modified SAE) integrate faster than implants with SAE surface. The stability gain of the test group was 2.24 times faster than the control group after 5 weeks of evaluation at the posterior region of the edentulous maxillae.

Prospective randomized clinical trial of hydrophilic tapered implant placement at maxillary posterior area: 6 weeks and 12 weeks loading

PURPOSE

Early loading of implant can be determined by excellent primary stability and characteristic of implant surface. The implant system with recently improved surface can have load application 4-6 weeks after installing in maxilla and mandible. This study evaluated the effect of healing period to the stability of hydrophilic tapered-type implant at maxillary posterior area.

MATERIALS AND METHODS

This study included 30 patients treated by hydrophilic tapered-type implants (total 41 implants at maxilla) and classified by two groups depending on healing period. Group 1 (11 patients, 15 implants) was a control group and the healing period was 12 weeks, and Group 2 (19 patients, 26 implants) was test group and the healing period was 6 weeks. Immediately after implant placement, at the first impression taking, implant stability was measured using Osstell Mentor. The patients also took periapical radiographs after restoration delivery, 12 months after restoration and final followup period. The marginal bone loss around the implants was measured using the periapical radiographs.

RESULTS

All implants were survived and success rate was 97.56%. The marginal bone loss was less than 1mm after 1 year postoperatively except the one implant. The stabilities of the implants were not correlated with age, healing period until loading, insertion torque (IT), the diameter of fixture and the location of implant. Only the quality of bone in group 2 (6 week) was correlated with the stability of implant.

CONCLUSION

Healing period of 6 weeks can make the similar clinical prognosis of implants to that of healing period of 12 weeks if bone quality is carefully considered in case of early loading.

Effect of length, diameter, intraoral location on implant stability

OBJECTIVES

To quantitatively compare stability of dental implants with varying lengths, diameters, and intraoral locations.

STUDY DESIGN

Retrospectively, 200 consecutive NobelReplace Tapered Groovy implants of varying lengths and diameters were evaluated via implant stability quotient readings at placement (T1) and follow-up (T2). Data were analyzed by analysis of variance and simple linear regression tests.

RESULTS

Intraoral location was statistically significant at T1 and T2. Although implant diameter was not statistically significant, implant length resulted in T1 (P = .08) and T2 (P = .09), which may have a clinically relevant effect on implant stability. An overall implant survival rate of 98% was achieved. Gender and age did not seem to affect implant stability quotient values at placement, follow-up, or implant survival.

CONCLUSIONS

Intraoral location is an important factor in implant stability, with implants placed in the mandible being more stable than implants placed in the maxilla both at T1 and T2. Length may have a clinically relevant effect on implant stability.

Does Length, Diameter, or Bone Quality Affect Primary and Secondary Stability in Self-Tapping Dental Implants?

PURPOSE

Implant stability is a clinically valuable measurement of the strength of implant anchorage in the bone during placement and in the post-osseointegration period. This study aimed to determine 1) the effect of implant diameter and length and bone quality on measurements of primary and secondary stability (insertion torque [IT] and implant stability quotient [ISQ]), 2) the correlation between IT and primary and secondary ISQ, and 3) differences in ISQ in the post-osseointegration period (secondary stability) compared with immediate post-placement (primary) stability.

PATIENTS AND METHODS

In this longitudinal clinical study, titanium self-tapping implants were inserted in edentulous patients. The implants were grouped according to 3 independent variables: length (10 and 11.5 mm), diameter (3.75 and 4.25 mm), and bone quality (Lekholm and Zarb classification) to analyze primary and secondary implant stability (outcome variables). Statistical analyses were performed using the Student t test for paired data, 1-way analysis of variance, and the Tukey procedure for multiple pairwise comparisons.

RESULTS

Data were collected on 88 self-tapping implants inserted in 63 partially edentulous patients. IT and implant stability were affected by diameter (3.75-mm implants, 26.5-N/cm IT and 74.0 ISQ; 4.25-mm implants, 33.8-N/cm IT and 77.0 ISQ) and bone type (type 1 + 2, 34.86-N/cm IT and 77.4 ISQ; type 3, 27.09-N/cm IT and 75.6 ISQ; type 4, 20.63-N/cm IT and 70.5 ISQ; P < .01 for all comparisons). Secondary ISQ was affected by diameter only (77.41 for 3.75- vs 75.51 for 4.25-mm implants). IT correlated with primary ISQ (R = 0.56; P < .01), although no clear correlation with secondary stability was found.

CONCLUSIONS

IT and primary ISQ in self-tapping implants differed in patients with different bone quality and implant diameter but did not differ between the 2 implant lengths compared in this study. Secondary stability was not substantially affected by any of these factors. Although IT was closely related to primary ISQ, it was unrelated to secondary ISQ. Very high primary ISQ values tended to decrease, whereas intermediate and low values tended to increase, in the transition to secondary stability.

Implant stability change and osseointegration speed of immediately loaded photofunctionalized implants

OBJECTIVES

This study evaluated the degree and rate of implant stability development for photofunctionalized dental implants in humans.

MATERIALS AND METHODS

Thirty-three implants (7 patients) placed in the maxilla and immediate loaded were evaluated. Photofunctionalization was performed by treating implants with ultraviolet for 15 minutes immediately before placement. Implant stability was assessed by measuring the implant stability quotient (ISQ) weekly starting from implant placement up to 3 months. Osseointegration speed index (OSI), defined as ISQ increase per month, was also evaluated.

RESULTS

The average ISQ for photofunctionalized implants at week 6 was 78.0, which was considerably higher than the average ISQ of 66.1, reported in literature for various as-received implants after a longer healing time of 2 to 6 months. No stability dip was observed for photofunctionalized implants regardless of the initial ISQ values. The OSI for photofunctionalized implants was 6.3 and 3.1 when their initial ISQ was 65 to 70 and 71 to 75, respectively, whereas the OSI values for as-received implants calculated from literature ranged from -3.0 to 1.17 with an average of -0.10.

CONCLUSIONS

Photofunctionalization accelerated and enhanced osseointegration of dental implants, providing novel and practical avenues for further advancement in implant therapy.

Effect of implant design on primary stability using torque-time curves in artificial bone

Background

Primary stability following implant placement is essential for osseointegration and is affected by both implant design and bone density. The aim of this study was to compare the relationships between torque-time curves and implant designs in a poor bone quality model.

Methods

Nine implant designs, with five implants in each category, were compared. A total of 90 implants (Straumann: Standard RN, Bone Level RC, Tapered Effect RN; Nobel Biocare: Brånemark MKIII, MKIV) were placed in type IV artificial bone. Torque-time curves of insertion and removal were recorded at the rate of 1000 samples/s by a torque analyzer.

Results

The torque-time curves were divided into initial, parallel, tapered, and platform areas. The mean torque rise rate of the parallel area was smallest at 0.36 N · cm/s, with a significant difference from those of the other areas (p < 0.05). Values of 2.14, 2.33, and 2.65 N · cm/s were obtained for the initial, tapered, and platform areas, respectively. The removal torque for six of the implant designs (Bone Level RC 8, 10, and 12 mm; Tapered Effect RN 10 mm; Brånemark MKIII 10 mm, MKIV 10 mm) was significantly smaller than the corresponding insertion torque (p < 0.05). However, the removal torque for ST6, 8, and 10 was almost the same as or slightly greater than the corresponding insertion torque.

Conclusions

The insertion torque-time curves and design features of the implants were accurately transferred. Increasing implant taper angle appeared to increase the torque rate. Torque was mainly generated from the superior surface to the valley of the thread and the inferior and axial surfaces of the platform, while the inferior and axial surfaces of the thread did not significantly affect torque generation.

Modified titanium implant as a gateway to the human body: the implant mediated drug delivery system

The aim of this study was to investigate the efficacy of a proposed new implant mediated drug delivery system (IMDDS) in rabbits. The drug delivery system is applied through a modified titanium implant that is configured to be implanted into bone. The implant is hollow and has multiple microholes that can continuously deliver therapeutic agents into the systematic body. To examine the efficacy and feasibility of the IMDDS, we investigated the pharmacokinetic behavior of dexamethasone in plasma after a single dose was delivered via the modified implant placed in the rabbit tibia. After measuring the plasma concentration, the areas under the curve showed that the IMDDS provided a sustained release for a relatively long period. The result suggests that the IMDDS can deliver a sustained release of certain drug components with a high bioavailability. Accordingly, the IMDDS may provide the basis for a novel approach to treating patients with chronic diseases.

Primary stability of self-drilling and self-tapping mini-implant in tibia of diabetes-induced rabbits

Objective. This study aimed to evaluate effects of type 1 diabetes mellitus and mini-implant placement method on the primary stability of mini-implants by comparing mechanical stability and microstructural/histological differences. Methods. After 4 weeks of diabetic induction, 48 mini-implants (24 self-tapping and 24 self-drilling implants) were placed on the tibia of 6 diabetic and 6 normal rabbits. After 4 weeks, the rabbits were sacrificed. Insertion torque, removal torque, insertion energy, and removal energy were measured with a surgical engine on 8 rabbits. Remaining 4 rabbits were analyzed by microcomputed tomography (micro-CT) and bone histomorphometry. Results. Total insertion energy was higher in self-drilling groups than self-tapping groups in both control and diabetic groups. Diabetic groups had more trabecular separation in bone marrow than the control groups in both SD and ST groups. Micro-CT analysis showed deterioration of bone quality in tibia especially in bone marrow of diabetic rabbits. However, there was no statistically significant correlation between self-drilling and self-tapping group for the remaining measurements in both control and diabetic groups. Conclusions. Type 1 diabetes mellitus and placement method of mini-implant did not affect primary stability of mini-implants.

Heat generated during seating of dental implant fixtures

Frictional heat can be generated during seating of dental implants into a drill-prepared osteotomy. This in vitro study tested the heat generated by implant seating in dense bovine mandible ramus. A thermocouple was placed approximately 0.5 mm from the rim of the osteotomy during seating of each dental implant. Four diameters of implants were tested. The average temperature increases were 0.075°C for the 5.7-mm-diameter implant, 0.97°C for the 4.7-mm-diameter implant, 1.4°C for the 3.7-mm-diameter implant, and 8.6°C for the 2.5-mm-diameter implant. The results showed that heat was indeed generated and a small temperature rise occurred, apparently by the friction of the implant surface against the fresh-cut bone surface. Bone is a poor thermal conductor. The titanium of the implant and the steel of the handpiece are much better heat conductors. Titanium may be 70 times more heat conductive than bone. The larger diameter and displacement implant may act as a heat sink to draw away any heat produced from the friction of seating the implant at the bone-implant interface. The peak temperature duration was momentary, and not measured, but this was approximately less than 1 second. Except for the 2.5-mm-diameter implants, the temperature rises and durations were found to be below those previously deemed to be detrimental, so no clinically significant osseous damage would be expected during dental implant fixture seating of standard and large-diameter-sized implants. A 2.5-mm implant may generate detrimental heat during seating in nonvital bone, but this may be clinically insignificant in vital bone. The surface area and thermal conductivity are important factors in removing generated heat transfer at the bone-implant interface. The F value as determined by analysis of variance was 69.22, and the P value was less than .0001, demonstrating significant differences between the groups considered as a whole.

Mini-implant stability at the initial healing period: a clinical pilot study

OBJECTIVE

To evaluate the changes of mini-implant stability over the initial healing period in humans.

MATERIAL AND METHODS

A sample of 19 consecutively treated patients (mean age 15.5 ± 7.3 years) was examined. In each patient, a mini-implant of a size of 2 × 9 mm was inserted into the anterior palate. Implant stability was assessed using resonance frequency analysis (RFA) immediately after insertion (T0), 2 weeks later (T1), 4 weeks later (T2), and 6 weeks later (T3). Insertion depth (ID) and the maximum insertion torque (IT) were measured. Data were tested for correlations between RFA, ID, and IT. All RFA values were tested for statistically significant differences between the different times.

RESULTS

The mean ID was 7.5 ± 0.6 mm, and the mean IT was 16.8 ± 0.6 Ncm. A correlation was found between RFA and ID (r = .726, P < .0001), whereas no correlations between RFA and IT or between IT and ID were observed. From T0 to T1, the stability (36.1 ± 6.1 implant stability quotient [ISQ]) decreased nonsignificantly by 4.9 ± 6.1 ISQ values (P > .05). Between T1 and T2, the stability decreased highly significantly (P < .001) by 7.9 ± 5.9 ISQ values. From T2 on, RFA remained nearly unchanged (-1.7 ± 3.5 ISQ; P > .05).

CONCLUSIONS

Mini-implant stability is subject to changes during the healing process. During weeks 3 and 4, a significant decrease of the stability was observed. After 4 weeks, the stability did not change significantly.

Biomechanical determinants of the stability of dental implants: influence of the bone-implant interface properties

Dental implants are now widely used for the replacement of missing teeth in fully or partially edentulous patients and for cranial reconstructions. However, risks of failure, which may have dramatic consequences, are still experienced and remain difficult to anticipate. The stability of biomaterials inserted in bone tissue depends on multiscale phenomena of biomechanical (bone-implant interlocking) and of biological (mechanotransduction) natures. The objective of this review is to provide an overview of the biomechanical behavior of the bone-dental implant interface as a function of its environment by considering in silico, ex vivo and in vivo studies including animal models as well as clinical studies. The biomechanical determinants of osseointegration phenomena are related to bone remodeling in the vicinity of the implants (adaptation of the bone structure to accommodate the presence of a biomaterial). Aspects related to the description of the interface and to its space-time multiscale nature will first be reviewed. Then, the various approaches used in the literature to measure implant stability and the bone-implant interface properties in vitro and in vivo will be described. Quantitative ultrasound methods are promising because they are cheap, non invasive and because of their lower spatial resolution around the implant compared to other biomechanical approaches.