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... Its determination is done by a torque gauge incorporated within the drilling unit or with a torque wrench during the insertion of the implant [1,10]. It can only be measured once, when the implant is being placed, so the monitoring of the implant stability through IT is not possible [27]. IT measures the mechanical frictional resistance of the bone bed to apical implant advance, rotating about its longitudinal axis, whereas ISQ is based on the stiffness of implant contact with bone and therefore its resistance to lateral micromovements [6]. ...
... However, these parameters measure two different mechanical concepts, the IT represent the axial resistance force of the bed bone preparation while the implant is inserted. The ISQ values represent the lateral stiffness between the implant surfaces and bone preparation [27,29,31]. However, the inverse relationship between ISQ values and micromotion has been previously documented [6]. ...
... The IT represents the axial resistance force of the bed bone preparation while the implant is inserted. The ISQ values represent the lateral stiffness between the implant surfaces and bone preparation [27,29,31]. ...
Article
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In order to apply the “one-abutment–one-time” concept, we evaluated the possibility of measuring resonance frequency analysis (RFA) on the abutment. This trial aimed to compare the Implant Stability Quotient (ISQ) values obtained by the PenguinRFA when screwing the transducer onto the implant or onto abutments with different heights and angulations. Eighty implants (VEGA®, Klockner Implant System, SOADCO, Les Escaldes, Andorra) were inserted into fresh bovine ribs. The groups were composed of 20 implants, 12 mm in length, with two diameters (3.5 and 4 mm). Five different abutments for screwed retained restorations (Permanent®) were placed as follows: straight with 1, 2, and 3 mm heights, and angulated at 18° with 2 and 3 mm heights. The mean value of the ISQ measured directly on the implant was 75.72 ± 4.37. The mean value of the ISQ registered over straight abutments was 79.5 ± 8.50, 76.12 ± 6.63, and 71.42 ± 6.86 for 1, 2, and 3 mm height abutments. The mean ISQ over angled abutments of 2 and 3 mm heights were 68.74 ± 4.68 and 64.51 ± 4.53 respectively. The present study demonstrates that, when the ISQ is registered over the straight abutments of 2 and 3 mm heights, the values decrease, and values are lower for angled, 3 mm height abutments.
... 31 F I G U R E 1 Implant removed using forceps by means of unscrewing motion to break the bone-to-implant connection A histomorphometric and clinical experimental study in dogs provided some insights into the dynamic process of buccolingual peri-implant bone remodeling 8 weeks following implant placement. 32 The authors reported that when thick buccal bone (greater than 1.5 mm) was present, the vast majority of histomorphometric variables remained more stable when compared with scenarios in which thin buccal bone was present (less than 1.5 mm). In a separate part of the study, a ligature-based model was employed to test the hypothesis that implants placed in thin buccal bone are at higher risk of developing more severe forms of peri-implant disease. ...
... Peri-implantitis progressed in a more aggressive fashion with implants placed less than 1.5 mm from the buccal flange. 32 It is important to recognize that ligature models provide some insights into natural pathology, but they are acute models of peri-implantitis and may not directly translate to the natural human disease, which is chronic in nature. Given the multiple variables that contribute to the development of peri-implantitis, the effect of a "critical buccal bone thickness" upon the peri-implant tissue characteristics was also investigated. ...
... Therefore, it was concluded that a buccal bone thickness greater than 1.5 mm appears to be more effective in 34 This has also been observed with implants placed into healed alveolar ridges, on the assumption that the surgeon is attempting to minimize injury to anatomical boundaries, such as 25 In line with the concept of a "critical buccal bone thickness," implants should be placed greater than 1.5 mm from the buccal bone plate. 32 Wherever this cannot be guaranteed, guided bone regeneration simultaneously with implant placement should be undertaken to limit the remodeling process. ...
Article
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Inappropriate and unnecessary implant therapy driven by an erroneous belief that dental implants provide enhanced function and esthetics over diseased or failing teeth has led to a growing burden of implant complications across the globe. Specifically, esthetic and biological complications frequently lead to the unfavorable prognosis of dental implants. Often, these cannot be managed predictably to improve the condition or satisfy patients' demands. In such circumstances, implant removal needs to be considered. Currently, minimally invasive methods based on reverse torque engineering are key to preserve peri‐implant soft and hard tissues. Implant replacement is now feasible, as evidenced by the high survival rates of implants placed at previously failed sites. Notwithstanding these data, clinicians should still consider carefully the expendability of an implant and whether its replacement will satisfy the prosthetic, biomechanical, and esthetic demands of the patient. In the scenario where future implant placement is desired, protocols undertaken for soft/hard tissue grafting and implant placement should be based upon defect morphology and soft and hard‐tissue characteristics. Currently, however, a lack of knowledge of the biological events and dimensional changes that arise following implant removal renders decision‐making complex and challenging, and recommendations remain largely based upon empirical speculation. This chapter will review the indications for implant replacement for prosthetic, biomechanical, and esthetic complications, alongside considerations in decision‐making, planning, implementation, and outcomes of implant replacement.
... Moreover, the correlation obtained between ISQ and BIC measurement in the present study was relatively weak. Note that there is also controversy in the literature regarding the dependence of BIC and ISQ, since some studies conclude with a signicant correlation between ISQ and BIC [4,196,240] with p-values varying between 0.016 and 0.024, while other studies showed there was no correlation between the two aforementioned parameters [3,51,113,130,178]. ...
... However, the QUS device was dierent since the ultrasonic probe was manually positioned on the implant abutment screw, leading to reproducibility issues, whereas a controlled insertion torque is introduced in the present study. Moreover, the relationship between the ISQ and BIC values have also been previously investigated[3, 4,51,113,130,178,196,240] (see subsection 8.4.3) but none of these studies considered QUS measurements.8.4.2 Evolution of ISQ, UI and BIC values with healing timeWhile a consistent increase of BIC values was obtained for lower values of healing time (0-8 weeks), BIC values obtained for higher healing duration (8-13 weeks) tend to decrease (seeTable 8.1) and have an important variability depending on the implant considered.A similar behavior was obtained in previous studies realized with Labrador dogs[3] and on sheep[283] (seeFig. 2.9). ...
... .4. Stability assessment methods values is also weakly understood[51,113,130,178,240,247]. Finally, the xation and orientation of the transducer were shown to signicantly inuence ISQ measurements[35,211,283,284,285]. ...
Thesis
While surgical interventions involving the use of endosseous implants are now routinely performed, failures still occur and may have dramatic consequences. The clinical outcome depends on osseointegration processes, which correspond to the growth of bone in intimate contact with the implant. This work focuses on the development of quantitative ultrasound (QUS) techniques for the characterization of the biomechanical properties of the bone-implant interface (BII), which are the main determinant for the success of osseointegration.First, an in vitro approach is carried out to assess the sensitivity of the QUS response of the BII to loading conditions. Trabecular bovine bone samples are compressed onto coin-shaped implants and the ultrasonic response of the BII is measured during compression. A significant decrease of the reflection coefficient of the BII as a function of the stress is obtained until a plateau is reached, corresponding to bone fracture.Second, finite element modeling and simulations are performed in order to distinguish the effects of different parameters on the ultrasonic response of the BII. In particular, the impact of the implant surface roughness is investigated at the microscopic and macroscopic scales. An analytical model of the ultrasonic propagation at the BII is also proposed. The reflection coefficient of the BII is shown to significantly decrease when (i) the BII is better osseointegrated, (ii) the roughness amplitude decreases, (iii) the central frequency of ultrasound decreases and (iv) bone mass density increases. Moreover, interference phenomena are evidenced at the macroscopic scale.Third, in silico, in vitro and in vivo studies are combined to investigate the use of QUS methods to estimate dental implant stability. Ultrasound propagation inside a dental implant is examined using laser-interferometric techniques. First arriving signal and spectral analyses evidence the propagation of a guided wave mode along the implant axis, which is confirmed by numerical simulation. An in vivo study is performed to compare the performances of QUS and of resonance frequency analysis to estimate dental implant stability in a rabbit model. The QUS results were shown to have a better sensitivity to changes of bone quantity and quality during the osseointegration processes.By coupling experimental and numerical approaches, this work provides new insights to better understand the propagation of ultrasonic waves at the BII. Moreover, it proves the performances of a future medical device that could assess dental implant stability.
... Based on an a priori power analysis considering the dog as the independent variable (27) Housing conditions as well as the protocols carried out for pre-anesthesia, local anesthesia and postoperative pain control medication have been reported elsewhere (28,29). ...
... The protocols referred to tooth extraction and implant placement have been detailed elsewhere (28,29). Briefly, each dog underwent atraumatic mandibular premolar and molar extractions (PM3, PM4, M1) in the hemiarches. ...
... The detailed ligature-induced peri-implantitis protocol can be found elsewhere (28,29). Briefly, after 8 weeks of healing, silk ligatures (3/0) were placed looping the apical portion of the implant-supported healing abutments and changed three weeks apart for a total of three events (T1-T3). ...
Article
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Purpose: There is a lack of knowledge concerning the critical buccal bone thickness required for securing favorable functional and esthetic outcomes, conditioned to the dimensional changes after implant placement. A preclinical study was therefore carried out to identify the critical buccal bone wall thickness for minimizing bone resorption during physiologic and pathologic bone remodeling. Materials and methods: A randomized, two-arm in vivo study in healthy beagle dogs was carried out. The first group of dogs was sacrificed 8 weeks after implant placement for histomorphometric examination of postsurgical resorption of the buccal bone wall. The second group of dogs was monitored during three ligature-induced peri-implantitis episodes and a spontaneous progression episode. Morphometric and clinical variables were defined for the study of physiologic and pathologic buccal and lingual bone loss. Results: Seventy-two implants were placed in healed mandibular ridges of 12 beagle dogs. Two groups were defined: 36 implants were placed in sites with a thin buccal bone wall (< 1.5 mm), and 36 were placed in sites with a thick buccal bone wall (≥ 1.5 mm). No implants failed during the study period. For the great majority of the histomorphometric parameters, a critical buccal bone wall thickness of at least 1.5 mm seemed to be essential for maintaining the buccal bone wall during physiologic and pathologic bone resorption. Suppuration (+) and mucosal recession (-) were more often associated with implants placed in sites with a thin buccal bone wall. Conclusion: A critical buccal bone wall thickness of 1.5 mm at implant placement is advised, since a thicker peri-implant buccal bone wall (> 1.5 mm) is exposed to significantly less physiologic and pathologic bone loss compared with a thinner buccal bone wall (< 1.5 mm).
... Liposomes are biodegradable and biocompatible. In addition, technically it is feasible to functionalize liposome to react to light, pH, and other stimuli which made them the most frequent clinically applied nanoscale delivery system with many commercialized types [110]. Schematic diagram of Oliveira's approach for using Dendron-like nanoparticles for dexamethasone delivery in bone defects [99]. ...
... Coating on metal alloys becomes sometimes an important aspect to prevent the release of metal ions such as Ni, Ti, and Ag [97,98]. Although various polymer composite coatings have been tried on metal alloy especially NiTi, there has always been difficult to make successful coatings [99][100][101][102][103][104][105][106][107][108][109][110][111]. The drawbacks of polymers coating include roughness, porosity, nonuniformity, and toxicity of the components [112]. ...
... More than 40% of the implants diagnosed with peri-implantitis presented with a too-buccal position [76]. The critical buccal bone thickness for preventing buccallingual bone resorption is estimated to be 1.5 mm [110]. An insufficient amount of crestal bone favors peri-implantitis development as a consequence of the implant's micro-rough surface contamination by the plaque-associated bacteria causing its chronic infection [110]. ...
Chapter
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The objective of research in implantology is to provide materials and surfaces that could accelerate the healing and osteogenesis, minimize the failures, and provide long-term success. The production of treated surfaces with additive or subtractive techniques have permitted to increase the bone–implant contact, to accelerate the loading protocols and decrease the early failures; some authors have hypothesized that the increased wettability of these novel surfaces could also increase the bacterial adhesion and the risk of peri-implantitis; however, there are many parameters that influence the biofilm formation. One of these is represented by the average roughness, Ra, but also other factors, like free energy, chemistry, and titanium purity, have a great role in the establishment of the microbiota. In this chapter, we will discuss the novel materials and surfaces that could decrease early failure and improve long-term success in implantology.
... More than 40% of the implants diagnosed with peri-implantitis presented with a too-buccal position [76]. The critical buccal bone thickness for preventing buccallingual bone resorption is estimated to be 1.5 mm [110]. An insufficient amount of crestal bone favors peri-implantitis development as a consequence of the implant's micro-rough surface contamination by the plaque-associated bacteria causing its chronic infection [110]. ...
... The critical buccal bone thickness for preventing buccallingual bone resorption is estimated to be 1.5 mm [110]. An insufficient amount of crestal bone favors peri-implantitis development as a consequence of the implant's micro-rough surface contamination by the plaque-associated bacteria causing its chronic infection [110]. On the other hand, an apico-coronal implant position might dictate the long-term stability of the peri-implant tissues [9]. ...
Chapter
Since decades, dental implantology has become a vital and ubiquitous rehabilitation treatment method, providing edentulous or semi-edentulous patients with an artificial dentition. Along with the popularity of dental implants, the problems with their maintenance in the oral cavity have gradually evolved, leading to confusion over classification, recognition, treatment, and prevention of diseases correlated with them. In 2017, the World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions developed a new classification of periodontal diseases, in which peri-implant health problems were separately outlined. The experts came to an agreement that placement of dental implants has led to the occurrence of new clinical problems related to them. Peri-implant diseases, such as peri-implant mucositis and peri-implantitis, correspond to periodontal states, gingivitis and periodontitis, and, likewise, are considered serious and chronic diseases jeopardizing the undertaken rehabilitation treatment. Peri-implantitis, which is defined as a pathologic condition of all tissues supporting dental implant, can lead to its loss, if not recognized and treated on time. In this chapter, the etiology of peri-implant health problems was assessed. Moreover, risk factors influencing the state of periodontal tissues supporting dental implants were distinguished, facilitating recognition of patients at risk and establishement of possible treatment methods. This chapter aims to bring closer prevalence and risk factors of peri-implantitis. Prevention and treatment methods are distinguished in this paper.
... However, the properties of the BII (17) cannot be directly identified through RFA, and the orientation of the device was found to significantly affect the ISQ score (18). The correlation between the ISQ and bone implant contact (BIC) is relatively weak and remains a subject of debate (19)(20)(21)(22)(23). Moreover, sensitivity issues of ISQ to changes of periprosthetic bone tissue have been raised, due to the fact that only the first bending mode is considered (24). ...
... However, the QUS device was different since the ultrasonic probe was manually positioned on the implant abutment screw, leading to reproducibility issues, whereas a controlled insertion torque is introduced in the present study. Moreover, the relationship between the ISQ and BIC values have also been previously investigated (19)(20)(21)(22)(23)(45)(46)(47) (see subsection 4.3) but none of these studies considered QUS measurements. The present study shows that QUS measurements (i) are better correlated to BIC values and (ii) have lower errors compared to RFA measurements. ...
Article
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Purpose: Quantitative ultrasound (QUS) and resonance frequency analyses (RFA) are promising methods to assess the stability of dental implants. The aim of this in vivo preclinical study is to compare the results obtained with these two techniques with the bone-implant contact (BIC) ratio, which is the gold standard to assess dental implant stability. Methods: Twenty-two identical dental implants were inserted in the tibia and femur of 12 rabbits, which were sacrificed after different healing durations (0, 4, 8 and 13 weeks). For each implant, the ultrasonic indicator (UI) and the implant stability quotient (ISQ) were retrieved just before the animal sacrifice using the QUS and RFA techniques, respectively. Histomorphometric analyses were carried out to estimate the bone-implant contact ratio. Results: UI values were found to be better correlated to BIC values (R²=0.47) compared to ISQ values (R²=0.39 for measurements in one direction and R²=0.18 for the other direction), which were shown to be dependent on the direction of measurements. Errors realized on the UI were around 3.3 times lower to the ones realized on the ISQ. Conclusions: QUS provide a better estimation of dental implant stability compared to RFA. This study paves the way for the future clinical development of a medical device aiming at assessing dental implant stability in a patient-specific manner. Clinical studies should confirm these results in the future.
... The outcome is expressed as the "implant stability quotient (ISQ)". This method is very popular and has been used in a myriad of clinical research articles that have shown a correlation between the evolution of osseointegration and the ISQ values (Meredith et al., 1997;Monje et al., 2018). In addition, failing implants have been related to a decrease in ISQ values until eventual loss of the implant, which implies a possible application of RFA to the diagnostics of implant failure. ...
... Nevertheless, although the tested implants lost more than 60% osseointegration, which necessitates implant removal in a clinical setting, the measured ISQ values were all in the range considered as "successful osseointegration" (>60). In addition, no conclusive correlation was reported between the BIC and ISQ values (Monje et al., 2018). ...
Article
The resonant frequency analysis (RFA) is a routinely used technique to assess dental implant stability. However, its sensitivity to the condition of the bone-implant interface remains largely unexplored. This paper investigates the RFA by means of numerical (finite element) simulations of short conical implants inserted into realistic jawbone sections. Two cases are examined. The first consists of a systematic variation in the bone-implant contact (BIC) using a random generation of the contact points in the two bone components. The results of the analyses show that beyond a BIC of ca. 20%, the RFA does not vary significantly, indicating a lack of sensitivity to further osseointegration. The next topic concerns peri-implantitis, as simulated firstly by a deterministic progressive detachment of the bone-implant interface. The main result of this simulation is that the RFA-BIC relationship is radically different for the osseointegration and bone recess phases, indicating a sensitivity to the location of the BIC in the bone components (random vs. deterministic). Finally, the simulation of a realistic peri-implantitis cylindrical crater of various depths shows no difference with respect to the previously analyzed interfacial bone detachment, indicating that the exact geometry of the peri-implantitis crater is of little if no influence on the RFA results.
... RFA has long been introduced into clinical practice to offer a quantitative value of implant stability, assuming that higher ISQ values correspond to a higher level of implant stability and osseointegration. Over the years, many studies have been carried out to determine the accuracy of the RFA as a method to assess implant stability, 13 but to date, clinical trials are still rare. However, RFA is not commonly used to determine the implant stability. ...
Article
Purpose: Primary stability is the most important prognostic index for predicting osseointegration. It is generally thought that to achieve high primary stability, it is necessary to insert an implant with a high insertion torque (IT). To date, it has not yet been determined whether IT and implant stability quotient (ISQ) values are correlated. The primary aim of the study was to determine the correlation between IT and ISQ values at the time of implant insertion (T0); at 2 months, the time of healing (T1); and at 6 (T2) and 12 months (T3) after loading. The secondary aims were to determine the influence of different macroscopic implant designs and of a different insertion arch on this correlation; and to assess whether implants inserted with a high IT, that is, > 50 Ncm, had higher levels of implant stability at 2-, 6-, and 12-month follow-ups. Materials and methods: STROBE guidelines were followed. Partially or monoedentulous patients were randomly assigned to receive taper thread on straight-body implants with microthreads (group A) or without microthreads (group B). At implant insertion, IT and ISQ values were recorded. At 2-, 6-, and 12-month follow-ups, the ISQ values were recorded. A spring-style torque wrench was used to assess the IT. The Osstell device was used to determine the ISQ values. Descriptive statistics, Pearson correlation, and t test were used. P was set at ≤ .005. Results: Two hundred fifty subjects were assessed; 142 were included. Two hundred sixty-eight implants were inserted (group A, 137 implants; group B, 131 implants). No subject dropped out, and no implant failed. A statistically significant correlation between ISQ and IT was determined at the time of implant insertion (T0; P = .000). The implant morphology and arch did not influence the correlation. An IT > 50 did not determine a higher secondary stability. Conclusion: There is a strong correlation between IT and primary stability, but IT is not correlated with the secondary stability. A different implant macroscopic design and a different arch of insertion did not influence this correlation. Moreover, implants inserted with IT > 50 Ncm do not result in greater secondary stability.
... It was further demonstrated that the ISQ values are dependent on the implant surface, showing a greater reduction with sandblasted acidetched implants compared with turned implants. 87 A recent canine study 88 yielded findings that are in agreement with previous results. The baseline ISQ increased during the healing phase, and thereafter, the ISQ values significantly decreased to 69.5 ± 1.30, showing a mean drop of 5.8%. ...
Article
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Purpose: This systematic review was prepared as part of the Academy of Osseointegration (AO) 2018 Summit, held August 8-10 in Oak Brook Hills, Illinois, to assess the relationship between the primary (mechanical) and secondary (biological) implant stability. Materials and methods: Electronic and manual searches were conducted by two independent examiners in order to address the following issues. Meta-regression analyses explored the relationship between primary stability, as measured by insertion torque (IT) and implant stability quotient (ISQ), and secondary stability, by means of survival and peri-implant marginal bone loss (MBL). Results: Overall, 37 articles were included for quantitative assessment. Of these, 17 reported on implant stability using only resonance frequncy analysis (RFA), 11 used only IT data, 7 used a combination of RFA and IT, and 2 used only the Periotest. The following findings were reached: ·Relationship between primary and secondary implant stability: Strong positive statistically significant relationship (P < .001). ·Relationship between primary stability by means of ISQ and implant survival: No statistically significant relationship (P = .4). ·Relationship between IT and implant survival: No statistically significant relationship (P = .2). ·Relationship between primary stability by means of ISQ unit and MBL: No statistically significant relationship (P = .9). ·Relationship between IT and MBL: Positive statistically significant relationship (P = .02). ·Accuracy of methods and devices to assess implant stability: Insufficient data to address this issue. Conclusion: Data suggest that primary/mechanical stability leads to more efficient achievement of secondary/biological stability, but the achievement of high primary stability might be detrimental for bone level stability. While current methods/devices for tracking implant stability over time can be clinically useful, a robust connection between existing stability metrics with implant survival remains inconclusive.
... Considering this, the assessment that the variation of stability values over time is related to changes in the bone-implant interface could not be scientifically proven. Using ligature-induced peri-implantitis models on Beagle dogs, Monje et al. [30] demonstrated a consistent negative correlation between ISQ measured by RFA and marginal bone loss over time, but they expressed doubt about the clinical relevance of using RFA as a diagnostic tool alone, as even though a statistical relationship was present, the implant stability values remained relatively high over the course of the study. However, the same and other authors agree on the fact that this lack of correlation could have been due to the use of inappropriate methods, citing the fact that a few histological sections from 2-D BIC models cannot represent the complete bone-implant interface; therefore, the analysis of 3-D models in relation to RFA measurements should be more representative [29]. ...
Article
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Background and Objectives: Implant stability in vivo is contingent on multiple factors, such as bone structure, instrument positioning and implant surface modifications, implant diameter, and implant length. Resonance-frequency analysis is considered a non-invasive, reliable, predictable, and objective method by which to evaluate implant stability, due to its correlation with bone-to-implant contact. The purpose of this study was to evaluate the effect of implant length on the primary and secondary stability of single-implant crown rehabilitations, as measured by resonance-frequency analysis at different times. Materials and Methods: Implants of 10 and 11.5 mm were placed, and the resonance frequency was measured at the time of surgery (T0), as well as at 3 (T1), 6 (T2), and 12 (T3) months post-surgery. Results: A total of 559 implants were placed in 195 patients. Significant differences were observed when comparing the implant stability quotient (ISQ) values at T1, with values for 10-mm implants being greater than those for 11.5-mm implants (p = 0.035). These differences were also observed when comparing ISQ values for buccal and lingual areas. At T0, T2, and T3, no significant differences in ISQ values were observed. The use of 10-mm implants in the anterior maxilla yielded significantly greater values at T0 (p = 0.018) and T1 (p = 0.031) when compared with 11.5-mm implants. Significant differences in measurements were observed only for buccal areas (p = 0.005; p = 0.018). When comparing the sample lengths and sex, women with 11.5-mm implants showed significantly lower results than those with 10-mm implants (p < 0.001). Conclusions: There is a direct relationship between implants of a smaller length and greater ISQ values, with this relationship being most evident in the maxilla and in women.
... The results of this study reveal that the probe orientation (mesial, distal, buccal, palatal/lingual) has no influence on ISQ values when records are measured with the SmartPeg screwed directly to the implant or to the experimental transepithelial abutments. These findings are in consonance with those published by Sim and Lang [14] although differ from previously published results that considered the probe orientation is able to influence resonance frequency values [10,34,36]. Although there is no statistically significant difference between the probe position (p < 0.5), a decrease in ISQ values may be registered in the vestibular position for all the tested groups: This may depend on the fact that buccal plates usually are thinner [37]. ...
Article
Full-text available
Resonance frequency analysis (RFA) requires abutment disconnection to monitor implant stability. To overcome this limitation, an experimental transepithelial abutment was designed to allow a SmartPeg to be screwed onto it, in order to determine the prototype abutments repeatability and reproducibility using Osstell ISQ and to assess whether implant length and diameter have an influence on the reliability of these measurements. RFA was conducted with a SmartPeg screwed directly into the implant and onto experimental abutments of different heights of 2, 3.5 and 5 mm. A total of 32 patients (116 implants) were tested. RFA measurements were taken twice for each group from mesial, distal, buccal and palatal/lingual surfaces. Mean values and SD were calculated and Intraclass Correlation Coefficients (ICC) (p < 0.05, IC 95%). The implant stability quotient (ISQ) mean values were 72.581 measured directly to implant and 72.899 (2 mm), 72.391 (3.5 mm) and 71.458 (5 mm) measured from the prototypes. ICC between measurements made directly to implant and through 2-, 3.5- and 5-mm abutments were 0.908, 0.919 and 0.939, respectively. RFA values registered through the experimental transepithelial abutments achieved a high reliability. Neither the implant length nor the diameter had any influence on the measurements' reliability.
... This is consistent with previous investigations performed in dog models in which mucosal redness was identified as an accurate diagnostic tool for monitoring PI progression. 32 Interestingly, most of the patients of this study perceived their general gingival health, peri-implant soft tissue health, and prosthesis condition as being positive. These results are in agreement with those of Zitzmann et al. 33 and Yao et al., 34 where patient satisfaction improved significantly in all the studied domains after the completion of treatment. ...
Article
Background: Dental plaque biofilm is considered to be the underlying cause of peri-implant diseases. Moreover, it has been corroborated recently the association between the presence of these diseases and deficiently designed implant-supported prostheses. In this regard, professional-administered oral hygiene measures have been suggested to play a dominant role in prevention. Material and methods: A cross-sectional study was conducted in dental implant patients according to accessibility for self-performed oral hygiene using a 0.5mm interproximal brush. Periodontal and peri-implant status were assessed based on clinical and radiographic variables to determine the prevalence of peri-implant diseases. In addition, the participants completed a questionnaire on the efficiency and accessibility for self-performed proximal hygiene. Associations of descriptive data were analyzed using the chi-squared test and Mann-Whitney U-test. Correlations of the variables with the primary outcome (accessibility) were assessed by means of generalized estimation equations and multilevel logistic regression models. Results: Based on an a priori power calculation, a total of 50 patients (171 implants) were consecutively recruited. From these, 46% of the prostheses allowed proper access for performing proximal hygiene while 54% of the prostheses precluded proper access. Poor access for proximal hygiene displayed tendency towards statistical significance with peri-implant disease (OR = 2.31; p = 0.090), in particular with peri-implant mucositis (OR = 2.43; p = 0.082) when compared to good access. In addition, an association was observed to increased levels of mucosal redness (p = 0.026) and the full-mouth bleeding score (p = 0.018). On the other hand, the presence of peri-implant disease was related to self-reported assessment of oral hygiene measures (p = 0.015) and to patient perception of gingival/mucosal bleeding when performing oral hygiene (p = 0.026). In turn, the diagnosis of peri-implant disease was significantly associated to the quantity and quality of information provided at the time of implant therapy (p = 0.004), including the influence of confounders upon disease occurrence (p = 0.038) CONCLUSIONS: To a certain extent, accessibility for self-performed proximal hygiene is associated to the peri-implant condition. On the other hand, the information received by the patient from the dental professional is essential for self-monitoring of the peri-implant conditions and for alerting to the possible presence of disorders. This article is protected by copyright. All rights reserved.
... As published elsewhere, 15 ...
Article
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Objective: To evaluate microbial and host-derived biomarker changes during experimental peri-implantitis in the Beagle dog. Background: Limited data exist on the microbial and biomarker changes during progressive bone loss as result of experimental peri-implantitis. Methods: In total, 36 implants (ndogs = 6) were assessed over 3 episodes of ligature induced peri-implantitis followed by a period of spontaneous progression. Implants with hybrid (H) and completely rough (R) surface designs were used. Clinical and radiographic parameters were recorded at 4 timepoints. Peri-implant sulcus fluid was collected from the buccal and lingual aspects of the implants. The presence of 7 bacterial species and 2 host-derived biomarkers was assessed during the study period. Results: Total bacterial counts were significantly correlated with marginal bone loss (MBL) (r = .21; P = .009). Further, Phorphyromonas gulae (Pg) and Tannerella forsythia (Tf) were commonly correlated with MBL, suppuration (SUP) and the sulcular bleeding index scores (mSBI) (P < .05). Other bacteria were further correlated with SUP, mSBI, and MBL. While the analyzed bacteria dropped, Prevotella intermedia (Pi) further increased during the spontaneous progressive phase (P < .05). Total bacterial load did not differ significantly between H and R implants. Host derived IL-10 was undetected along the study period. IL-1β positively correlated with probing pocket depth (r = .18; P = .03). During spontaneous progression, H implants displayed statistically significant lower levels of IL-1β (P = .003). Conclusion: Experimental peri-implantitis is associated with an increase in bacterial counts. While Pg and Tf are associated with ligature-induced disease progression, Pi augmented its load during the spontaneous progressive phase. IL-1β is associated with pocket probing depth and influenced by implant surface characteristics during the spontaneous progression phase.
... In this sense, if marginal bone loss leads to a worse biomechanical behavior of bone-implant complex with higher bone deformation and implant micromovement, it could be diagnosed using RFA devices with a decrease in implant stability quotient (ISQ) values. In this respect, several studies have shown the influence of periimplant bone defects on ISQ values using RFA devices, suggesting it a potential use in the diagnosis of peri-implant disease [42,43]. ...
Article
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Methods: Three models of a single internal connection bone level-type implant inserted into a posterior mandible bone section were constructed using a 3D finite element software: one control model without marginal bone loss and two test models, both with a circumferential peri-implant bone defect, one with a 3 mm high defect and the other one 6 mm high. A 150 N static load was tested on the central fossa at 6° relative to the axial axis of the implant. Results: The results showed differences in the magnitude of strain and stress transferred to the bone between models, being the higher strain found in the trabecular bone around the implant with greater marginal bone loss. Stress distribution differed between models, being concentrated at the cortical bone in the control model and at the trabecular bone in the test models. Conclusion: Marginal bone loss around dental implants under occlusal loading influences the magnitude and distribution of the stress transferred and the deformation of peri-implant bone, being higher as the bone loss increases.
... A recent study has demonstrated that the critical buccal bone thickness for preventing marked physiological buccal-lingual bone resorption is 1.5 mm. In the absence of this thickness, more pronounced peri-implantitis may occur as a consequence of the microrough surface exposed to the oral cavity-facilitating surface contamination and the chronification of peri-implant infection [59] (Figure 6). ...
Article
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The prevalence of implant biological complications has grown enormously over the last decade, in concordance with the impact of biofilm and its byproducts upon disease development. Deleterious habits and systemic conditions have been regarded as risk factors for peri-implantitis. However, little is known about the influence of local confounders upon the onset and progression of the disease. The present narrative review therefore describes the emerging local predisposing factors that place dental implants/patients at risk of developing peri-implantitis. A review is also made of the triggering factors capable of inducing peri-implantitis and of the accelerating factors capable of interfering with the progression of the disease.
Chapter
Implant-related pathologic bone loss is the most common problem but not limited only to infectious diseases. Before focusing on peri-implant disease treatment; predisposing local factors, such as cement remnants, bruxism, and systemic factors must be evaluated and eliminated before local treatment attempt. Peri-implant infections are reversible while limited in gingival tissue level. However, irreversible and progressive when infiltrates to connective and bone tissue. The treatment of peri-implant infections must cover the removal of gross debris (debridement), and eradication of biofilm from the implant surface to achieve bone regeneration. The bone regeneration following those steps can be achieved with bone grafting or guided bone regeneration techniques. Mobility of the implant indicates the removal of the implant. A biopsy must be obtained from those peri-implant diseases, which do not respond to any of these treatment modalities or have an unusual clinical appearance.
Article
Objective: To compare the early changes in implant stability of Implants with different neck design during the first 3 months of healing in the posterior maxilla. Materials and methods: Patients were randomized to receive triangular neck implant (test), or round neck implant (control). Resonance frequency analysis (ISQ) measurements were obtained at surgery and at 2, 4, 7, 14, 21, 28, 45, 60 and 90 days following implant placement. Non-parametric statistic was used for data analysis. Results: 32 patients were included (17 test, 15 controls). Initial ISQ values of the test implants were high (mean 68.4, SD=8.4), and increased over time (mean 74.4, SD=6.0). Control implants presented a statistically significant higher initial ISQ value at implant placement (mean 76.9, SD=8.7) which was maintained over the healing period (mean 77.6, SD=3.6) with no significant changes between time intervals. After 6 weeks of healing, both implants displayed comparable ISQ values with no differences between the groups. All implants exhibited a decrease in stability on day 2 and 21 post-placement. All round-neck implants used and 82% of the triangular-neck implants showed initial ISQ values above the suggested threshold for immediate loading (>60). Conclusions: Implant neck design plays a role in implant primary stability in the posterior maxilla. Both implant show high primary stability, with significantly higher values for the round neck. However, these differences disappeared after 6 weeks of healing. While primary implant stability is partially governed by implant neck design, the role of this result is negligible for the achievement of secondary stability.
Article
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Objectives: To answer the focused question, 'In animals or patients with dental implants, does implant surface characteristics and/or implant material have an effect on incidence and progression of peri-implantitis?' Material and methods: Pre-clinical in vivo experiments on experimental peri-implantitis and clinical trials with any aim and design, and ≥5 years follow-up, where the effect of ≥2 different type of implant material and/or surface characteristics on peri-implantitis incidence or severity, and/or progression, implant survival or losses due to peri-implantitis, and/or marginal bone levels/loss was assessed. Results: Meta-analyses based on data of pre-clinical experiments, using the ligature induced peri-implantitis model in the dog, indicated that after the spontaneous progression phase implants with a modified surface showed significantly greater radiographic bone loss (effect size 0.44 mm; 95%CI 0.10-0.79; p = .012; 8 publications) and area of infiltrated connective tissue (effect size 0.75 mm2 ; 95%CI 0.15-1.34; p = .014; 5 publications) compared to non-modified surfaces. However, in 9 out of the 18 included experiments, reported in 25 publications, no significant differences were shown among the different implant surface types assessed. Clinical and/or radiographic data from 7605 patients with 26,188 implants, reported in 31 publications (20 RCTs, 3 CTs, 4 prospective cohort, and 4 retrospective studies; 12 with follow-up ≥10 years), overall did not show significant differences in the incidence of peri-implantitis, when this was reported or could be inferred, among the various implant surfaces. In general, high survival rates (90-100%) up to 30 years and no clinically relevant differences in marginal bone loss/levels, merely compatible with crestal remodelling, were presented for the various implant types. Conclusion: Pre-clinical in vivo experiments indicate that surface characteristics of modified implants may have a significant negative impact on peri-implantitis progression, while clinical studies do not support the notion that there is a difference in peri-implantitis incidence among the various types of implant surfaces. No assumptions can be made regarding the possible impact of implant material on incidence and/or peri-implantitis progression due to limited information.
Article
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The aim of the present clinical study was to determine the local bone density in dental implant recipient sites using computerized tomography (CT) and to investigate the influence of local bone density on implant stability parameters and implant success. A total of 300 implants were placed in 111 patients between 2003 and 2005. The bone density in each implant recipient site was determined using CT. Insertion torque and resonance frequency analysis were used as implant stability parameters. The peak insertion torque values were recorded with OsseoCare machine. The resonance frequency analysis measurements were performed with Osstell instrument immediately after implant placement, 6, and 12 months later. Of 300 implants placed, 20 were lost, meaning a survival rate of %. 93.3 after three years (average 3.7 +/- 0.7 years). The mean bone density, insertion torque and RFA recordings of all 300 implants were 620 +/- 251 HU, 36.1 +/- 8 Ncm, and 65.7 +/- 9 ISQ at implant placement respectively; which indicated statistically significant correlations between bone density and insertion torque values (p < 0.001), bone density and ISQ values (p < 0.001), and insertion torque and ISQ values (p < 0.001). The mean bone density, insertion torque and RFA values were 645 +/- 240 HU, 37.2 +/- 7 Ncm, and 67.1 +/- 7 ISQ for 280 successful implants at implant placement, while corresponding values were 267 +/- 47 HU, 21.8 +/- 4 Ncm, and 46.5 +/- 4 ISQ for 20 failed implants; which indicated statistically significant differences for each parameter (p < 0.001). CT is a useful tool to determine the bone density in the implant recipient sites, and the local bone density has a prevailing influence on primary implant stability, which is an important determinant for implant success.
Article
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The aim of the present study was to determine the correlation between the primary stability of dental implants placed in edentulous maxillae and mandibles, the bone mineral density and different histomorphometric parameters. After assessing the bone mineral density of the implant sites by computed tomography, 48 stepped cylinder screw implants were installed in four unfixed human maxillae and mandibles of recently deceased people who had bequeathed their bodies to the Anatomic Institute I of the University of Erlangen-Nuremberg for medical-scientific research. Peak insertion torque, Periotest values and resonance frequency analysis were assessed. Subsequently, histologic specimens were prepared, and bone-to-implant contact, the trabecular bone pattern factor (TBPf), the density of trabecular bone (BV/TV) and the height of the cortical passage of the implants were determined. The correlation between the different parameters was calculated statistically. The mean resonance frequency analysis values (maxilla 6130.4+/-363.2 Hz, mandible 6424.5+/-236.2 Hz) did not correlate with the Periotest measurements (maxilla 13.1+/-7.2, mandible -7.9+/-2.1) and peak insertion torque values (maxilla 23.8+/-2.2 N cm, mandible 45.0+/-7.9 N cm) (P=0.280 and 0.193, respectively). Again, no correlations could be found between the resonance frequency analysis, the bone mineral density (maxilla 259.2+/-124.8 mg/cm(3), mandible 349.8+/-113.3 mg/cm3), BV/TV (maxilla 19.7+/-8.8%, mandible 34.3+/-6.0%) and the TBPf (maxilla 2.39+/-1.46 mm-1, mandible -0.84+/-3.27 mm-1) (P=0.140 and 0.602, respectively). However, the resonance frequency analysis values did correlate with bone-to-implant contact of the oral aspect of the specimens (maxilla 12.6+/-6.0%, mandible 35.1+/-5.1%) and with the height of the crestal cortical bone penetrated by the implants in the oral aspect of the implant sites (maxilla 2.1+/-0.7 mm, mandible 5.1+/-3.7 mm) (P=0.024 and 0.002, respectively). The Periotest values showed a correlation with the height of the crestal cortical bone penetrated by the implants in the buccal aspect of the implant sites (maxilla 2.5+/-1.2 mm, mandible 5.4+/-1.2 mm) (P=0.015). The resonance frequency analysis revealed more correlations to the histomorphometric parameters than the Periotest measurements. However, it seems that the noninvasive determination of implant stability has to be improved in order to give a more comprehensive prediction of the bone characteristics of the implant site.
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To review the literature on clinical, radiographic, and biochemical parameters used for monitoring peri-implant conditions. A MEDLINE search was conducted that included articles published in English until the end of August 2003. Results from human and experimental animal studies are presented. The parameters that may be used to assess the presence of peri-implant health and the severity of peri-implant disease include plaque assessment, mucosal conditions, peri-implant probing depth, width of the peri-implant keratinized mucosa, periimplant sulcus fluid analysis, suppuration, implant mobility and discomfort, resonance frequency analysis, and radiographic evaluation. Based on the analysis of the available evidence, it appears reasonable to use a number of clinical and radiographic parameters to discriminate between peri-implant health and disease. Systematic and continuous monitoring of peri-implant tissues during maintenance care is recommended for the early diagnosis of peri-implant disease.
Article
Background: Resonance Frequency Analysis (RFA) is widely applied to assess implant stability, as expressed by Implant Stability Quotient (ISQ). However, the relation between ISQ value and the presence and extent of narrow marginal bone defects around implants has not been documented. Purpose: To investigate the potential of RFA devices to identify the presence and extent of marginal bone defects around implants, as expressed by the ISQ values. Materials and methods: 28 Straumann bone level implants (BL) and 28 bone level tapered implants (BLT), were placed ex-vivo in porcine ribs. The implants were divided into four groups. Implants in group A were fully submerged in the bone with no marginal bone defect. In the other groups implants were placed with a 0.9mm circumferential marginal bone defect extending 2mm (B), 4mm (C) and 6mm (D) apically. Two devices (Osstell Gothenburg, Sweden and Penguin Integration Diagnostics AB, Gotheburg, Sweden) were used to measure each implant stability, taking three measurements from buccal and mesial direction. The ISQ values were recorded and analysed. Results: ISQ values generated by two devices decreased as the defects depth increased, with the greatest reduction observed between full bone (A) and 2 mm defect (B) (p<0.001). No significant differences were found in the ISQ values recorded from BL implants and BLT implants in this model. Conclusion: ISQ values can effectively detect narrow, intrabony marginal bone defects, in particular when involving the first coronal 2mm. This finding could have significant implications for the early diagnosis of conditions affecting the marginal bone, such as peri-implantitis. Further research in clinical conditions is required to investigate if such findings can be replicated after osseointegration is achieved. This article is protected by copyright. All rights reserved.
Article
To cluster peri-implantitis patients and explore nonlinear patterns in peri-implant bone levels. Clinical and radiographic variables were retrieved from 94 implant-treated patients (340 implants, mean 7.1 ± 4.1 years in function). Kernel probability density estimations on patient mean peri-implant bone levels were used to identify patient clusters. Interrelationships of all variables were evaluated by principal component analysis; a k-nearest neighbors method was performed for supervised prediction of implant bone levels at the patient level. Self-similar patterns of mean bone level per implant from different jaw bone sites were examined and their associated fractal dimensions were estimated. Two clusters of implant-treated patients were identified, one at patient mean bone levels of 1.7 mm and another at 4.0 mm. Five of thirteen available variables (number of teeth, age, gender, periodontitis severity, years of implant service), were predictive for peri-implant bone levels. A high jaw bone fractal dimension was associated with less severe peri-implantitis. Nonlinearity of peri-implantitis was evidenced by finding different peri-implant bone levels between two main clusters of implant-treated patients and among six different jaw bone sites. The patient mean peri-implant bone levels were predicted from 5 variables and confirmed complexity for peri-implantitis. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
Article
Background To develop preventive strategies addressing peri-implant diseases, a thorough understanding of the epidemiology is required.AimThe aim was to systematically assess the scientific literature in order to evaluate the prevalence, extent and severity of peri-implant diseases.Material & Methods Data were extracted from identified studies. Meta-analyses for prevalence of peri-implant mucositis and peri-implantitis were performed. The effect of function time and disease definition on the prevalence of peri-implantitis was evaluated by meta-regression analyses. Data on extent and severity of peri-implant diseases was estimated if not directly reported.Results15 articles describing 11 studies were included. Case definitions for mucositis and peri-implantitis varied. The prevalence of peri-implant mucositis and peri-implantitis ranged from 19-65% and from 1-47%, respectively. Meta-analyses estimated weighted mean prevalences of peri-implant mucositis and peri-implantitis of 43% (CI: 32-54%) and 22% (CI: 14-30%), respectively. The meta-regression showed a positive relationship between prevalence of peri-implantitis and function time and a negative relationship between prevalence of peri-implantitis and threshold for bone loss. Extent and severity of peri-implant diseases were rarely reported.Conclusion Future studies on the epidemiology of peri-implant diseases should consider (i) applying consistent case definitions and (ii) assessing random patient samples of adequate size and function time.This article is protected by copyright. All rights reserved.
Article
Purpose: The aim of this study was to test the sensitivity of the resonance frequency analysis for detecting early implant failure. Materials and Methods: In all, 3,786 implants placed from June 2007 to January 2013 were retrospectively evaluated. A total of 20 implants (in 20 patients) placed in pristine bone were found to have failed before loading. The implant stability quotient (ISQ) values were extracted from these 20 implants at baseline (immediate) and 4 months after placement (delayed). Simple linear regression, logistic regression, and two-way contingency tables were used to test for the relationships between ISQ values and early implant failure. Results: Immediate ISQ values were significantly related to failure (odds ratio [OR] = 4.27). Furthermore, the results of the second regression showed a significant relationship between ISQ at delayed measurement and implant failure (OR = 9.20). For immediate ISQ, it seems that the 73.7% correct classifications were obtained at the cost of an incorrect classification of 55% of the implant failures. However, for the delayed ISQ, 86.2% correct classifications were obtained at the cost of assuming that all implants will survive. Conclusion: The present study showed that ISQ values are not reliable in predicting early implant failure. In addition, the real cutoff ISQ value to differentiate between success and early implant failure remains to be determined.
Article
To study implant primary stability and bone healing using resonance frequency analysis in different anatomical locations 4 months after placement. Fifty-six partially edentulous patients restored by dental implants were included. Overall, 214 implants were placed without bone or soft tissue augmentation. All implants were placed with the same drilling protocol and implant insertion torque (35-40 N·cm). The mean implant stability quotient (ISQ) value at baseline for all the locations was 75.4 mm (95% confidence interval, 74.20-76.59 mm). Higher ISQ values were found in the mandible. A significant difference between ISQ values of each location (P < 0.001) was identified. The mean values obtained showed an increase (3.4%) in all the locations, being greater in the posterior lower and upper maxillae (3.8%), whereas for the anterior maxilla, it was the least (1.5%) 4 months after healing. This increase was statistically significant in the posterior upper and lower maxillae (P < 0.001). Higher implant stability was found in mandible compared with maxilla in both periods, immediately after insertion and 4 months later. Therefore, according to ISQ values, restoring implants immediately after insertion or after a healing period of 4 months represents safe time points.
Article
Background: Histologic studies have demonstrated the possibility to reestablish direct bone-implant contacts after ligature-induced periimplantitis. The influence of the reosseointegration on the stability of implants is not known. Purpose: The aim of the present investigation was to study bone tissue and associated implant stability alterations that occurred during induction and resolution of periimplantitis using resonance frequency analysis (RFA), radiography, and histology. Materials and methods: Three implants with smooth (turned) or roughened (SLA) surfaces were placed in each side of the edentulous mandible of four dogs. Experimental periimplantitis was induced for 3 months. Five weeks later, the animals were treated with antibiotics and surgical therapy and were followed for another 6 months. Periapical radiographs and RFA were used to evaluate marginal bone levels and implant stability throughout the study period. After termination, the tissue-implant interface was evaluated by light microscopy in ground sections. Results: There was a linear relationship between radiographic and RFA findings because continuous loss of marginal bone and a decrease in implant stability were observed for both implant surfaces during the periimplantitis period. Antibiotic treatment and surgical therapy resulted in some reosseointegration, which was more marked for the SLA surface. The resonance frequency values corresponded well to the histometric measurements because reosseointegration resulted in an increase in implant stability. Conclusions: The findings from the present study indicate a linear relationship between marginal bone level and resonance frequency value. It is suggested that the RFA technique is sensitive and may be used to detect even a minor change in the level of bone-implant contact.
Article
Peri-implant diseases present in two forms - peri-implant mucositis and peri-implantitis. The literature was systematically searched and critically reviewed. Four manuscripts were produced in specific topics identified as key areas to understand the microbial aetiology and the pathogenesis of peri-implant diseases and how the implant surface structure may affect pathogenesis. While peri-implant mucositis represents the host response of the peri-implant tissues to the bacterial challenge that is not fundamentally different from gingivitis representing the host response to the bacterial challenge in the gingiva, peri-implantitis may differ from periodontitis both in the extent and the composition of cells in the lesion as well as the progression rate. A self-limiting process with a "protective" connective tissue capsule developing appears to dominate the periodontitis lesion while such a process may occasionally be lacking in peri-implantitis lesions. Bacterial biofilm formation on implant surfaces does not differ from that on tooth surfaces, but may be influenced by surface roughness. Nevertheless there is no evidence that such differences may influence the development of peri-implantitis. It was agreed that clinical and radiographic data should routinely be obtained after prosthesis installation on implants in order to establish a baseline for the diagnosis of peri-implantitis during maintenance of implant patients.
Article
Implant primary stability is a prerequisite for implant success. A dehiscence or a circumferential defect (CD) at the time of implant placement presents a challenge for achieving primary stability. The aim of this study was to examine the correlations between implant primary stability determined by resonance frequency analysis (RFA) and periimplant bone levels. Ten implants were placed in 2 cadaver heads. A series of different sizes of narrow (NDD) and wide (WDD) dehiscence defects and CDs were surgically created around 6 and 4 implants, respectively. Implant primary stability in each size of the 3 different defect types was measured with RFA. For each defect type, the association between the RFA readings and the defect size was plotted and statistically analyzed. In NDD study, the RFA readings were not correlated with the defect size. In WDD study, the association was significant for most implants, with the coefficient correlation (r) ranging from -0.88 to -0.97. In CD study, there was also a significant association between the implant stability quotient readings and the bone levels, and the r ranged from -0.94 to -0.99. The association between implant primary stability measured by RFA and the size of surrounding bone defects was defect type dependent. The correlation was highly significant for WDD and CD but not for NDD.
Article
Given that the orientation of the transducer (mesiodistal or buccolingual) affects the data obtained from a piezoelectric resonance frequency analysis (RFA), this study evaluated whether it is necessary to use measurements taken in two different directions (mesiodistal and buccolingual) when using magnetic RFA to assess changes in the stiffness of dental implants. A prospective clinical trial was completed, in a total of 53 patients, on 71 non-submerged dental implants that were inserted to replace the unilateral loss of mandibular molars. All of the implants were of the same diameter (4.1 mm), length (10 mm), and collar height (2.8 mm). The implant stability quotient (ISQ) was measured during the surgical procedure, and at 4 and 10 weeks after surgery. Measurements were taken twice in each direction: in the buccolingual direction from the buccal side and in the mesiodistal direction from the mesial side. The average of two measurements in each direction was regarded as the representative ISQ of that direction. The higher and lower values of the two ISQs (buccolingual and mesiodistal) were also classified separately. In addition, the variation in ISQ was quantified by subtracting the lower value from the higher value, and the implants were classified into two groups according to this variation: one with ISQ variation of 3 or more and the other with a variation of <3. There were no differences between the two ISQs when measured from different directions, but there were significant differences between the higher and lower values of the ISQs at each measurement point. A significant difference was also observed between the two ISQ variation groups in the pattern of change of the lower value for the period from immediately after surgery to 10 weeks after surgery. Acquisition of two directional measurements and classification of the higher and lower values of the two directional ISQs may allow clinicians to detect patterns of change in ISQ that would not be identified if only one directional measurement were made.
Article
In the past, several modifications of specific surface properties such as topography, structure, chemistry, surface charge, and wettability have been investigated to predictably improve the osseointegration of titanium implants. The aim of the present review was to evaluate, based on the currently available evidence, the impact of hydrophilic surface modifications of titanium for dental implants. A surface treatment was performed to produce hydroxylated/hydrated titanium surfaces with identical microstructure to either acid-etched, or sand-blasted, large grit and acid-etched substrates, but with hydrophilic character. Preliminary in vitro studies have indicated that the specific properties noted for hydrophilic titanium surfaces have a significant influence on cell differentiation and growth factor production. Animal experiments have pointed out that hydrophilic surfaces improve early stages of soft tissue and hard tissue integration of either nonsubmerged or submerged titanium implants. This data was also corroborated by the results from preliminary clinical studies. In conclusion, the present review has pointed to a potential of hydrophilic surface modifications to support tissue integration of titanium dental implants.
Article
In the present animal experiment, analyses and comparisons were made between the structure and composition of clinically healthy supraalveolar soft tissues adjacent to implants and teeth. 5 beagle dogs were used. The right mandibular premolar region was selected in each dog for placement of titanium implants, while the left mandibular premolar region served as control. Extractions of the mandibular premolars were preformed, healing allowed, following which titanium fixtures were installed in the edentolous premolar region. Abutment connection was carried out 3 months later. After another 2 months of healing, plaque control was initiated and maintained for 8 weeks. At the end of the plaque control period, clinical examinations were performed and biopsies harvested from the implant site and the contralateral premolar tooth region. Following fixation and decalcification, all tissue samples were embedded in EPON and examined by histometric and morphometric means. The result from the analyses demonstrated that the periimplant mucosa which formed at titanium implants following abutment connection had many features in common with gingival tissue at teeth. Thus, like the gingiva, the peri-implant mucosa established a cuff-like barrier which adhered to the surface of the titanium abutment. Further, both the gingiva and the peri-implant mucosa had a well-keratinized oral epithelium which was continuous with a junctional epithelium that faced the enamel or the titanium surface. In the periimplant mucosa, the collagen fibers appeared to commence at the marginal bone and were parallel with the abutment surface. All gingival and periimplant units examined were free from infiltrates of inflammatory cells. It was suggested that under the conditions of study, both types of soft tissues, gingiva and periimplant mucosa, have a proper potential to prevent subgingival plaque formation.
Article
The purpose of the present study was to evaluate the influence of different surface characteristics on bone integration of titanium implants. Hollow-cylinder implants with six different surfaces were placed in the metaphyses of the tibia and femur in six miniature pigs. After 3 and 6 weeks, the implants with surrounding bone were removed and analyzed in undecalcified transverse sections. The histologic examination revealed direct bone-implant contact for all implants. However, the morphometric analyses demonstrated significant differences in the percentage of bone-implant contact, when measured in cancellous bone. Electropolished as well as the sandblasted and acid pickled (medium grit; HF/HNO3) implant surfaces had the lowest percentage of bone contact with mean values ranging between 20 and 25%. Sandblasted implants with a large grit and titanium plasma-sprayed implants demonstrated 30-40% mean bone contact. The highest extent of bone-implant interface was observed in sandblasted and acid attacked surfaces (large grit; HCl/H2SO4) with mean values of 50-60%, and hydroxylapatite (HA)-coated implants with 60-70%. However, the HA coating consistently revealed signs of resorption. It can be concluded that the extent of bone-implant interface is positively correlated with an increasing roughness of the implant surface.
Article
The aim of this investigation was to measure the resonance frequency of a number of implants placed in the rabbit tibia at insertion and at predetermined periods thereafter and to correlate the results with histomorphometric measurements made when the animals were sacrificed. Ten mature New Zealand White rabbits were used in the study. Two c.p. threaded titanium implants were placed in the right tibia of each animal. Resonance frequency measurements were made by screwing a small transducer onto a standard abutment mounted on each fixture. Measurements were repeated with the transducer oriented perpendicular and parallel to the long axis of the tibia for all proximal implants 14 and 28 days after placement and in 6 implants additionally at 42, 56, 93, 122 and 168 days after which all animals were sacrificed. Histomorphometric analysis comprised 2 parts; measurement of bone-implant contact area and height. A significant increase in resonance frequency was observed after 14 (405 Hz, +/- 234 Hz) and 28 (658 Hz, +/- 332 Hz) days. The increase in resonance frequency levelled after approximately 40 days and little further change was observed. The variation in bone-implant contact area was relatively small (1.8-4.9 mm2) and the range of bone-implant contact heights was also narrow (-1.5 (-)+ 1.5 mm). Values for resonance frequencies plotted against contact area and height were grouped around 10 kHz. In conclusion, it was shown that resonance frequency measurements can be made at placement and during healing in vivo and changes may be related to the increase in stiffness of an implant in the surrounding tissues.
Article
The aim of this investigation was to evaluate the use of resonance frequency measurements in the clinical measurement of implant stability. Resonance frequency measurements are undertaken by measuring the response of a small transducer attached to an implant fixture or abutment. Two groups of patients were selected for study. Group A comprised 9 patients who had a total of 56 implants placed. Resonance frequency measurements were made at fixture installation and repeated 8 months later at abutment connection. The resonance frequency of the implant/transducer system increased for 50 out of the 56 implants from a mean value of 7473 Hz +/- 127 Hz (P < 0.05) to a mean of 7915 Hz +/- 112 Hz (P < 0.05). Two implants had failed to integrate and the resonance frequency of these had fallen. Group B comprised 9 patients who had been provided with fixed prostheses and had a total of 52 implants placed. They were examined 5 years after fixture placement and the prostheses removed. All implants were judged clinically to be osseointegrated. The level of the marginal bone around each implant was calculated by measuring the number of exposed threads on intraoral periapical radiographs and added to the length of each abutment to give a value termed the effective implant length (EIL). Measurements indicated a correlation (R = -0.78, P < 0.01) between EIL and resonance frequency. The results support the hypothesis that the resonance frequency of an implant/transducer system is related to the height of the implant not surrounded by bone and the stability of the implant/tissue interface as determined by the absence of clinical mobility.
Article
This clinical study is the first to quantitatively evaluate both regional bone structure by computed tomography preoperatively and dental implant stability by resonance frequency analysis at the time of surgery to explore the relation between local bone structure and dental implant stability in humans. Implant stability at the time of installation is often difficult to achieve in lower density bone and implant stability might influence treatment efficacy. Few clinical studies have reported detailed bone characteristics obtained using computed tomography prior to surgery and comprehensive implant stability measurements at the time of surgery. We hypothesized that thicker cortical bone would improve the stability of the dental implant at the time of placement. Before radiographic examination, diagnostic radiographic templates were made by incorporating radiopaque indicators. Computed tomography scans were obtained for 50 edentulous subjects prior to surgery. Preoperatively, the thickness of the cortical bone at the sites of implant insertion was measured digitally, and then implant insertion surgery was performed. A total of 225-implant stability measurements were made using a resonance frequency analyzer. There was a strong linear correlation between cortical bone thickness and resonance frequency (r = 0.84, P < 0.0001). The implant length had a weak negative correlation with stability (r = -0.25, P < 0.0005). These results suggest that the initial stability at the time of implant installation is influenced more by cortical bone thickness than by implant length. The cortical and cancellous ratio of local bone is extremely important for implant stability at the time of surgery and determining the local bone condition is critical for treatment success.
Article
The aim of the present study was to test the hypothesis that measurements of implant stability using resonance frequency analysis (RFA) correlate with histomorphometric data of bone anchorage. Ten adult female foxhounds received a total of 80 implants in their mandibles 3 months after removal of all premolar teeth. At the time of implant placement, torque required for bone tapping was registered as a measure of bone density and immediately after placement implant stability was assessed using RFA. RFA measurements were repeated at the time of implant retrieval after 1 month (5 dogs) and 3 months (5 dogs). Peri-implant bone regeneration was assessed histomorphometrically by measuring bone-implant contact (BIC) and the volume density of the newly formed peri-implant bone (BVD). RFA values at the time of implant placement did not correlate with the torque required to tap the bone for implant placement. After 1 and 3 months, RFA values were significantly increased compared with baseline values. BIC and BVD, however, had increased significantly during this interval. There was no correlation between bone-implant contact and RFA values nor between peri-implant bone density and RFA values. Thus, the hypothesis could not be verified. It is concluded that the validity of the individual measurement of implant stability using RFA should be considered with caution.
Article
To monitor resonance frequency analysis (RFA) in relation to the jawbone characteristics and during the early phases of healing and incorporation of Straumann dental implants with an SLA surface. 17 Straumann 4.1 mm implants (10 mm) and 7 Straumann 4.8 mm implants (10 mm) were installed and ISQ determined at baseline and after 1, 2, 3, 4, 5, 6, 8 and 12 weeks. Central bone cores were analyzed from the 4.1 mm implants using micro CT for bone volume density (BVD) and bone trabecular connectivity (BTC). Pocket probing depths ranged from 2-4 mm and bleeding on probing from 5-20%. At baseline, BVD varied between 24% and 65% and BTC between 4.9 and 25.4 for the 4.1 mm implants. Baseline ISQ varied between 55 and 74 with a mean of 61.4. No significant correlations were found between BVD or BTC and ISQ Values. For the 4.8 mm diameter implants baseline ISQ values ranged from 57-70 with a mean of 63.3. Over the healing period ISQ values increased at 1 week and decreased after 2-3 weeks. After 4 weeks ISQ values, again increased slightly, no significant differences were noted over time. One implant (4.1 mm) lost stability at 3 weeks. Its ISQ value had dropped from 68 to 45. However the latter value was determined after the clinical diagnosis of instability. ISQ values of 57-70 represented homeostasis and implant stability. However no predictive value for loosing implant stability can be attributed to RFA since the decrease occurred after the fact.
Article
Clinical studies show promising outcomes with implants inserted at the time of extraction. However, this often results in an initial bone defect at the marginal region which preferably should heal for an optimal function. Therefore, monitoring of these implants is vital. The aims of this study were to determine the initial stability of implants placed into fresh extraction sockets, and to explore the correlations between the peri-implant bone levels and implant stability parameters. Six human cadaver mandibles including all natural teeth were selected for this study. All natural teeth were gently extracted, and 84 implants were immediately placed into fresh extraction sockets with five different implant depths. The maximum insertion torque values were recorded, and primary implant stability measurements were performed by means of resonance frequency analysis (RFA). The vertical distance between implant/abutment junction and the first bone-implant contact was recorded using a periodontal probe. It was found that the insertion torque and RFA were 28.9 +/- 7 Ncm and 65.6 +/- 9 implant stability quotient (ISQ), respectively, for 420 measurements from all 84 implants. Statistically significant correlation was found between insertion torque and ISQ values (r = 0.86; p < .001) for all implants. Both insertion torque and ISQ values dramatically decreased when the amount of peri-implant vertical bone defect increased. The results of this study demonstrated a linear relationship between peri-implant vertical bone defect depth and RFA value. It is proposed that the RFA method is sensitive to detect changes of the marginal bone level and may be used to monitor healing of peri-implant bone defects.
Animal research: Reporting in vivo experiments: The ARRIVE guidelines
  • Kilkenny
Kilkenny, C., Browne, W., Cuthill, I. C., Emerson, M., Altman, D. G., & Group, N. C. R. R. G. W. (2010). Animal research: Reporting in vivo experiments: The ARRIVE guidelines. The Journal of Gene Medicine, 12, 561-563. https://doi.org/10.1002/jgm.1473
Comparison of healed tissues adjacent to submerged and non-submerged unloaded titanium dental implants. A histometric study in beagle dogs
  • Weber
Weber, H. P., Buser, D., Donath, K., Fiorellini, J. P., Doppalapudi, V., Paquette, D. W., & Williams, R. C. (1996). Comparison of healed tissues adjacent to submerged and non-submerged unloaded titanium dental implants. A histometric study in beagle dogs. Clinical Oral Implants Research, 7, 11-19. https://doi. org/10.1034/j.1600-0501.1996.070102.x