Clinical Assessment of Dental Implant Stability During Follow-Up: What Is Actually Measured, and Perspectives

An Instrumented Hammer to Detect the Rupture of the Pterygoid Plates

PURPOSE

Craniofacial osteotomies involving pterygomaxillary disjunction are common procedures in maxillofacial surgery. Surgeons still rely on their proprioception to determine when to stop impacting the osteotome, which is important to avoid complications such as dental damage and bleeding. Our group has developed a technique consisting in using an instrumented hammer that can provide information on the mechanical properties of the tissue located around the osteotome tip. The aim of this study is to determine whether a mallet instrumented with a force sensor can be used to predict the crossing of the osteotome through the pterygoid plates.

METHODS

31 osteotomies were carried out in 16 lamb skulls. For each impact, the force signal obtained was analysed using a dedicated signal processing technique. A prediction algorithm based on an SVM classifier and a cost matrix was applied to the database.

RESULTS

We showed that the device could always detect the crossing of the osteotome, sometimes before its occurrence. The prediction accuracy of the device was 94.7%. The method seemed to be sensitive to the thickness of the plate and to crack apparition and propagation.

CONCLUSION

These results pave the way for the development of a per-operative decision support system in maxillofacial surgery.

Bone graft substitutes and dental implant stability in immediate implant surgery: a systematic review and meta-analysis

INTRODUCTION

Implant dentistry is currently being revolutionized by breakthroughs in techniques, technology, and material, there are few systematic reviews and meta-analyses that examine the effects of utilizing different bone graft substitutes in immediate implant placement surgeries.

AIM

The purpose of this research is to systematically review and meta-analyze the effect that different bone graft substitutes have on implant stability when concurrently utilized in patients undergoing immediate implant surgeries.

METHODOLOGY

The PICO criteria were used to construct the focused question, and the systematic review has been outlined as per the PRISMA guidelines. The revised Cochrane risk-of-bias method for randomized trials was used to assess the risk of bias for the selected articles. To derive estimates for the results, random effects meta-analysis was conducted on the selected articles.

RESULTS

The electronic databases were searched and a total of 1583 articles were identified. After title and abstract screening and due to problems in retrieval a further 1358 articles were eliminated. Fifteen articles were finally chosen to be qualified for review. Of which full text evaluation of 5 articles were found to meet the eligibility criteria and were therefore included in the systematic review.

CONCLUSION

This systematic review and meta-analysis on the stability of dental implants and bone graft substitutes in immediate implant surgery, was unable to draw any conclusions and established no statistically significant correlation between the different types of grafts used and implant stability.

Evaluation of the Transfemoral Bone-Implant Interface Properties Using Vibration Analysis

Evaluating the bone-implant interface (BII) properties of osseointegrated transfemoral (TFA) implants is important for early failure detection and prescribing loads during rehabilitation. The objective of this work is to derive and validate a 1D finite element (FE) model of the Osseointegrated Prosthetic Limb (OPL) TFA system that can: (1) model its dynamic behaviour and (2) extract the BII properties. The model was validated by: (1) comparing the 1D FE formulation to the analytical and 3D FE solutions for a simplified cylinder, (2) comparing the vibration modes of the actual TFA geometry using 1D and 3D FE models, and (3) evaluating the BII properties for three extreme conditions (LOW, INTERMEDIATE, and HIGH) generated using 3D FE and experimental (where the implant was embedded, using different adhesives, in synthetic femurs) signals for additional validation. The modes predicted by the 1D FE model converged to the analytical and the 3D FE solutions for the cylinder. The 1D model also matched the 3D FE solution with a maximum frequency difference of 2.02% for the TFA geometry. Finally, the 1D model extracted the BII stiffness and the system's damping properties for the three conditions generated using the 3D FE simulations and the experimental INTERMEDIATE and HIGH signals. The agreement between the 1D FE and the 3D FE solutions for the TFA geometry indicates that the 1D model captures the system's dynamic behaviour. Distinguishing between the different BII conditions demonstrates the 1D model's potential use for the non-invasive clinical evaluation of the TFA BII properties.

Correlation Between Implant Stability Quotient and Percussion Sound Frequency

OBJECTIVES

To determine the correlation between the primary implant stability quotient and the implant percussion sound frequency.

MATERIALS AND METHODS

A total of 14 pigs' ribs were scanned using a dental cone beam computed tomography (CBCT) scanner to classify the bone specimens into three distinct bone density Hounsfield units (HU) value categories: D1 bone: >1250 HU; D2: 850-1250 HU; D3: <850 HU. Then, 96 implants were inserted: 32 implants in D1 bone, 32 implants in D2 bone, and 32 implants in D3 bone. The primary implant stability quotient (ISQ) was analyzed, and percussion sound was recorded using a wireless microphone connected and analyzed with frequency analysis software.

RESULTS

Statistically significant positive correlations were found between the primary ISQ and the bone density HU value (r = 0.719; p < 0.001), and statistically significant positive correlations between the primary ISQ and the percussion sound frequency (r = 0.606; p < 0.001). Furthermore, significant differences in primary ISQ values and percussion sound frequency were found between D1 and D2 bone, as well as between D1 and D3 bone. However, no significant differences were found in primary ISQ values and percussion sound frequency between D2 and D3 bone.

CONCLUSION

The primary ISQ value and the percussion sound frequency are positively correlated.

Association between blood markers and the progression of osseointegration in percutaneous prostheses patients-A pilot study

Patients implanted with osseointegrated (OI) prosthetic systems have reported vastly improved upper and lower extremity prosthetic function compared with their previous experience with socket-suspension systems. However, OI systems have been associated with superficial and deep-bone infections and implant loosening due, in part, to a failure of the osseointegration process. Although monitoring the osseointegration using circulating biomarkers has clinical relevance for understanding the progression of osseointegration with these devices, it has yet to be established. Ten patients were enrolled in this study. Blood samples were collected at pre-selected times, starting before implantation surgery, and continuing to 12 months after the second surgery. Bone formation markers, bone resorption markers, and circulating amino acids were measured from blood samples. A linear mixed model was generated for each marker, incorporating patient ID and age with the normalized marker value as the response variable. Post hoc comparisons were made between 1 week before Stage 1 Surgery and all subsequent time points for each marker, followed by multiple testing corrections. Serial radiographic imaging of the residual limb containing the implant was obtained during follow-up, and the cortical index (CI) was calculated for the bone at the porous region of the device. Two markers of bone formation, specifically bone-specific alkaline phosphatase (Bone-ALP) and amino-terminal propeptide of type I procollagen (PINP), exhibited significant increases when compared with the baseline levels of unloaded residual bone prior to the initial surgery, and they subsequently returned to their baseline levels by the 12-month mark. Patients who experienced clinically robust osseointegration experienced increased cortical bone thickness at the porous coated region of the device. A medium correlation was observed between Bone-ALP and the porous CI values up to PoS2-M1 (p = .056), while no correlation was observed for PINP. An increase in bone formation markers and the lack of change observed in bone resorption markers likely reflect increased cortical bone formation induced by the end-loading design of the Utah OI device used in this study. A more extensive study is required to validate the correlation observed between Bone-ALP and porous CI values.

Influencing factors and evaluation methods for early stability of immediate implant

At present, implant restoration has become a hot research topic in the field of prosthodontics. The in-depth studies of new materials and new technologies enable immediate implantation, immediate and early loading to be realized, which meets the needs of patients for shortening the course of implant restoration and obtaining better aesthetic effects. However, compared with the traditional delayed implantation technology, it is equally challenging for clinicians how to achieve and even improve the initial and long-term stability of implants in order to raise the success rate of implant restoration. The initial stability of the implant is influenced by a combination of factors, including the implant, the patient's condition, and the surgical procedure. Recently, there have been a lot of studies on the influencing factors and common research methods for immediate implant stability and bone healing. Summarizing and analyzing them can provide reference for preoperative evaluation, surgical plan and loading timing of immediate implant restoration in the later stage.

Influence of implant length and insertion depth on primary stability of short dental implants: An in vitro study of a novel mandibular artificial bone model

Background/purpose

Dental implants are a mainstream solution for missing teeth. For the improvement of dental implant surface treatment and design, short dental implants have become an alternative to various complex bone augmentation procedures, especially those performed at the posterior region of both the maxilla and mandible. The objective of this study was to evaluate the effect of various insertion methods on the primary stability of short dental implants.

Materials and methods

Commercial dental implants were inserted into artificial mandibular bone specimens using various insertion methods (equicrestal position, subcrestal position 1.5 mm, and lateral cortical anchorage) in accordance with an implant surgical guide. Insertion torque value (ITV) curves were recorded while implant procedures were performed. Both maximum ITVs (MITVs) and final ITVs (FITVs) were evaluated. Subsequently, Periotest values (PTVs) and implant stability quotients (ISQs) were measured for all specimens. A Kruskal-Wallis test was conducted to analyze the results for four primary stability parameters, and the Dunn test was used for a post hoc pairwise comparison when a difference was identified.

Results

For all groups, their mean MITVs ranged from 33.6 to 59.4 N cm, whereas their mean FITVs ranged from 17.5 to 43.5 N cm. Insertion torque value, ISQ, and PTV decreased significantly when implants were inserted into subcrestal positions. When implants were inserted in the lateral bicortical position, the four aforementioned parameters yielded greater values.

Conclusion

When 6-mm short implants were inserted in a lateral cortical anchorage position, high primary stability was yielded.

Hydroxyapatite-Based Coatings on Silicon Wafers and Printed Zirconia

Dental surgery needs a biocompatible implant design that can ensure both osseointegration and soft tissue integration. This study aims to investigate the behavior of a hydroxyapatite-based coating, specifically designed to be deposited onto a zirconia substrate that was intentionally made porous through additive manufacturing for the purpose of reducing the cost of material. Layers were made via sol-gel dip coating by immersing the porous substrates into solutions of hydroxyapatite that were mixed with polyethyleneimine to improve the adhesion of hydroxyapatite to the substrate. The microstructure was determined by using X-ray diffraction, which showed the adhesion of hydroxyapatite; and atomic force microscopy was used to highlight the homogeneity of the coating repartition. Thermogravimetric analysis, differential scanning calorimetry, and Fourier transform infrared spectroscopy showed successful, selective removal of the polymer and a preserved hydroxyapatite coating. Finally, scanning electron microscopy pictures of the printed zirconia ceramics, which were obtained through the digital light processing additive manufacturing method, revealed that the mixed coating leads to a thicker, more uniform layer in comparison with a pure hydroxyapatite coating. Therefore, homogeneous coatings can be added to porous zirconia by combining polyethyleneimine with hydroxyapatite. This result has implications for improving global access to dental care.

The effect of different methods of cleansing temporary cement (with and without eugenol) on the final bond strength of implant-supported zirconia copings after final cementation: An in vitro study

Background

The temporary cement remaining inside the dental prosthesis can act as a source of microbial colonization and contamination and decrease the final cement retention. Consequently, complete removal of temporary cement before permanent cementation is suggested. This study aimed to assess the effect of different cleaning methods for removing temporary cement on the tensile bond force (TBF) of permanently cemented implant-supported zirconia copings.

Materials and Methods

In this in vitro study fifty titanium abutments were screwed onto 50 analogs with 30 Ncm torque into in acrylic resin blocks. Each abutment was scanned separately, and 50 zirconia copings were designed and milled. Permanent resin cement was used to cement copings of control group (N = 10). Copings were divided into two temporary cementation types that in each group, two cleansing methods were used: Temp-S (temporary cement with eugenol and sandblasted after debonding), Samples of the control group were placed in the universal testing machine, and the TBF values were recorded. Samples of the test groups after debonding and cleaning the abutments were subjected to cement with permanent resin cement, aging, and removing. Levene test, two-way analysis of variance (ANOVA), and Tamhane post hoc tests were applied. α = 0.05.

Results

The highest and lowest TBF values were found for the TempNE-SU (554.7 ± 31.5 N) and Temp-S (492.2 ± 48 N) groups, respectively. The two groups of isopropyl alcohol baths in ultrasonics in combination with sandblasting showed statistically higher TBF values than the other two groups that used only sandblasting (P < 0.001) and had similar values compared to the control group.

Conclusion

Sandblasting combined with immersion in an ultrasonic bath containing isopropyl alcohol resulted in statistically similar values to the values of cementation with resin cement from the beginning. However, cleaning the inside of the copings only by sandblasting method reduced the values of the final retention force in comparison to cement with permanent resin cement from the beginning.

Fractal Dimension as a Tool for Assessment of Dental Implant Stability-A Scoping Review

A lot of modalities for assessing implant stability are available for clinicians, but they fail to assess trabecular changes as they are solely dependent on the operator's skills. The use of Fractal Dimension (FD) has evolved to be used as a measure for trabecular changes depicting implant stability before and after implant placement. The objective of this systematic review was to qualitatively analyse the available scientific literature describing the use of FD as a tool to measure implant stability on the basis of trabecular changes. An electronic search in PubMed, Web of Science and Scopus was carried out using relevant keywords, such as: fractal dimension; fractal analysis; dental implants; implant stability; osseointegration, etc. Studies reporting the use of FD as a tool to measure implant stability were included and subjected to qualitative analysis using ROBINS-I and Cochrane risk of bias assessment criteria. Fourteen studies were included in this review. Results showed that FD was found to be used solely as a measure of implant stability in seven studies, out of which six studies showed an increment in FD values. The majority of studies concluded with a statistical correlation between FD and respective other assessment methods used. FD may not serve as a sole indicator of implant stability; however, it can be used as an adjunct to conventional methods along with additional fractal factors.

Evaluation of bone density by cone-beam computed tomography and its relationship with primary stability of dental implants

Background

One of the critical factors determining the success of dental implants is primary stability. This study aimed to determine the density of jawbones in the implant candidate sites via cone-beam computed tomography (CBCT) and its correlation with the values obtained from resonance frequency analysis during surgery.

Materials and Methods

In this descriptive-analytic study seventeen implant sites requiring implant placement were selected. Impressions were sent to the laboratory to construct a surgical guide via the stereolithographic method. An electronic surgery was performed on the chosen implant sites according to each patient's CBCT information entered into the Kaveh surgical guide software. The bone density of the target areas was calculated using the gray value (voxel value). After preparing the final osteotomy, an implant was installed in the area according to the manufacture's recommendation. The relevant Osstell^® SmartPeg was selected and installed on the implant body to determine the primary stability. Kolmogorov-Smirnov test and the correlation pearson correlation statistical test. used for statistical analyze. P value amounts < 0.05 was considered significant.

Results

The mean and standard deviation of the gray scale in this study were 563.7 ± 218.8 and 65.3 ± 7.7 implant stability quotient (ISQ) respectively. The correlation between gray scale and ISQ was evaluated by the Pearson correlation test, and the results indicated a strong correlation between the two variables.

Conclusion

The voxel value and primary stability had a normal distribution and strong correlation. In other words, the gray scale determined by CBCT imaging techniques at the proposed implant site could be used to assess the bone density before the surgery.

The developing patterns of calibrated implant stability quotients of posterior implants

Background/Purpose

Many surgical protocols were modified to improve implant stability. However, the conclusions of applying osteotome condensation technique could enhance implant stability were controversial. The evaluated implant stability quotients (ISQ) were calibrated to differentiate the implant stability improvement that applied by varied surgical techniques and the bone quality at recipient sites. Therefore, this study examine the developing patterns of calibrated ISQ values induced by osteotome bone condensation and conventional drilling technique at the posterior ridges.

Materials and methods

The ISQ values of 4.1/4.8-mm diameter implants were calibrated by 3.3-mm diameter implants (ISQ_b). Osteotome condensation technique was applied on the sites with ISQ_b ≤ 65 while those with ISQ_b > 65 were treated with conventional drilling technique. The implant ISQ values at Week 0, 1, 2, 3, 4, 6, 8, 10, 12 were recorded. The detected and calibrated ISQ values were statistically analyzed.

Results

Maxillary 14 implants and mandibular 16 implants using osteotome technique, maxillary 15 implants and mandibular 16 implants with conventional drilling technique were studied. Both techniques showed a generally similar ISQ developing pattern at both arches. Without calibration, significantly less ISQ values were noted for the osteotome technique of posterior maxilla at initial four weeks; subsequently, both techniques presented a comparable ISQ developing pattern. Osteotome technique demonstrated a greater ISQ increase after calibration on both arches (p < 0.05). All implants reached an ISQ stability plateau between Week 8 and 10.

Conclusion

With calibration, osteotome condensation technique could enhance greater primary and secondary implant stability for both arches.

Effect of advanced platelet-rich fibrin and concentrated growth factor on tissues around implants in maxillary anterior region

Aim

To assess the effect of advanced platelet-rich fibrin (APRF) and concentrated growth factor (CGF) on tissues around implants in the maxillary anterior region.

Settings and Design

This was a prospective clinical study.

Materials and Methods

Thirty subjects were divided into three groups with 10 dental implants in each group, i.e., Group 1: Control group, Group 2: Endosseous implant placement with APRF, and Group 3: Endosseous implant placement with CGF. The subjects were assessed at baseline (at the time of prosthesis placement), 2 weeks, 2 months, 6 months, and 1 year for modified sulcular bleeding index, periimplant probing depth, mucosal suppuration, bleeding on probing, crestal bone level as well as implant stability.

Statistical Analysis Used

Oneway Analysis of variance and Post hoc Bonferroni were the statistical tests used.

Results

The difference in implant stability at 2 months was significantly (P < 0.05) more among the control and CGF groups compared to APRF group. However; the crestal bone levels, periimplant probing depth, modified sulcular bleeding index, mucosal suppuration, and bleeding on probing were statistically non-significant (P > 0.05).

Conclusion

CGF and APRF accelerated osseointegration. Furthermore, they had a positive effect on stabilization values. However, CGF showed better results and with further clinical trials may show a positive effect on implant healing period.

Primary stability and PES/WES evaluation for immediate implants in the aesthetic zone: a pilot clinical double-blind randomized study

The use of immediate implants in the aesthetic area is a technique widely used in modern implantology. The characteristics of the patient, the implant, and the surgical procedure used may influence the final results. The aim was to assess whether the implant design affects primary (P.S.) and secondary stability (S.S.), bone level (B.L.), and PES/WES evaluation. Twenty implants with two different designs (n = 10) were immediately placed and randomly located in the upper anterior maxilla with no grafting material. Implant-Stability-Quotient (ISQ), B.L., and Pink-Esthetic-Score/White-Esthetic-Score (PES/WES) were evaluated. Shapiro–Wilk normality test was performed to determine the sample normality, as the data did not follow a normal distribution, the Wilcoxon-Mann–Whitney test was applied (p < 0.05). ISQ was determined at placement (PS): control 59.1 (C.I.54.8–63.3); experimental 62.2(C.I.60.1–64.2) and three months after placement (SS): control 62.2.1 (C.I.53.3–71.0); experimental 67.2(C.I.65.8–68.5). The BL was measured at three months after placement: control 0.38 mm (C.I.− 0.06 to  + 0.83); experimental 0.76 mm (C.I.0.33–1.19) and at 12 months post-loading: control 0.07 mm (C.I.− 0.50–0.65); experimental 0.90 mm (C.I.0.38–1.42). PES/WES values were evaluated for the control group: 15 (C.I.12.68–17.32), and for the experimental group 15.20 (C.I.11.99–18.41). No significant differences were shown between both implant designs. A good grade of osseointegration and primary/secondary stability was achieved, as well as proper maintenance of crestal bone and adequate PES/WES scores. The criteria for selection for the ideal patient for immediate implant placement is essential.

ClinicalTrials Protocol ID: NCT04343833.

Longitudinal Study of Dental Implants in HIV-Positive Patients

PURPOSE

This study compared the clinical outcome of dental implants and their implant-supported restorations over a 3-year period involving patients both positive and negative for the human immunodeficiency virus.

MATERIALS AND METHODS

Twenty patients testing positive for the human immunodeficiency virus were recruited for this study. Twenty-one negative control patients were also selected, for a total of forty one patients. Diagnostic impressions were collected and cone beam computed tomography images were obtained. Implant size and positioning were planned using cone beam computed tomography software. Two stage or single surgery was performed as determined by the surgeon (periodontist). After a 6-month healing period, definitive impressions were fabricated using polyvinyl siloxane impression material. Implant stability quotient values were obtained at the time of surgery and placement of the restoration. Screw-retained custom titanium abutments were designed, milled, and placed with 25 N·cm torque using a calibrated torque controller. Porcelain fused-to-metal complete coverage restorations were then cemented with elastomeric resin implant cement. Implants and restorations were assessed at 6-month intervals over a period of 3 years for stability, peri-implant health, and patient satisfaction.

RESULTS

Over the 3-year period, 25 of 42 implants placed in the negative control group were assessed, and 17 of 27 implants placed in the positive control group were evaluated. The overall patient retention rate was 77%. At the 3-year follow up, restorations examined were fully functional and causing no pain. Overall implant retention within the positive group was 96%. Implant retention within the negative control group was 100%. No differences were noted between groups for bone loss based on statistical tests.

CONCLUSION

Within the limitations of this clinical investigation, the presence of human immunodeficiency virus per se was not a contraindication to dental treatment with implant-supported restorations.

The Chairside Periodontal Diagnostic Toolkit: Past, Present, and Future

Periodontal diseases comprise a group of globally prevalent, chronic oral inflammatory conditions caused by microbial dysbiosis and the host immune response. These diseases specifically affect the tooth-supporting tissues (i.e., the periodontium) but are also known to contribute to systemic inflammation. If left untreated, periodontal diseases can ultimately progress to tooth loss, lead to compromised oral function, and negatively impact the overall quality of life. Therefore, it is important for the clinician to accurately diagnose these diseases both early and accurately chairside. Currently, the staging and grading of periodontal diseases are based on recording medical and dental histories, thorough oral examination, and multiple clinical and radiographic analyses of the periodontium. There have been numerous attempts to improve, automate, and digitize the collection of this information with varied success. Recent studies focused on the subgingival microbiome and the host immune response suggest there is an untapped potential for non-invasive oral sampling to assist clinicians in the chairside diagnosis and, potentially, prognosis. Here, we review the available toolkit available for diagnosing periodontal diseases, discuss commercially available options, and highlight the need for collaborative research initiatives and state-of-the-art technology development across disciplines to overcome the challenges of rapid periodontal disease diagnosis.

Factors Affecting Implant Stability Quotients at Immediately and Conventionally Loaded Implants in the Posterior Maxilla: A Split-Mouth Randomized Controlled Trial

PURPOSE

To assess primary and secondary stability of variable-thread tapered implants in the posterior maxilla and analyze the impact of various factors on implant stability quotients (ISQs).

MATERIALS AND METHODS

Twenty-six subjects received 3-4 adjacent implants in the maxillary premolar-molar sextants to replace bilateral tooth loss. The implants on one side were immediately loaded with a provisional fixed prosthesis regardless of their primary stability. The contralateral control implants were conventionally loaded. Bone quality was subjectively recorded and primary stability was assessed by means of insertion torque values (ITVs) and ISQs in 4 directions. Secondary stability was measured by ISQ at definitive prosthesis delivery (3-3.5 months postoperatively), and 12 months after definitive loading. The impact of measurement direction, loading protocol, time, site-related (bone quality, implant position, crestal buccal bone thickness, apical cortical anchorage), and implant-related (implant dimensions, abutment height) variables on ISQs was assessed.

RESULTS

For logistic reasons, ISQs were obtained for only 18 patients with 60 test and 60 control implants. Most of the implants (82%) at baseline had their lowest ISQ on the buccal aspect. There were no significant differences between ISQs measured in the buccal and palatal directions, or between ISQs in the mesial and distal directions. The mean of buccal and palatal ISQs was significantly lower than the mean of the 2 interproximal measurements at all evaluation periods. ISQs were not significantly different between the 2 loading groups at any time point. All implants showed a time-dependent increase in ISQs. Baseline ISQ correlated weakly with bone quality and ITV. None of the variables had a significant impact on baseline ISQs, except for implants in second molar sites which showed poorer primary stability than first premolars.

CONCLUSION

Measurement direction and time are the most significant parameters affecting ISQs of variable-thread tapered implants in the posterior maxilla.

Factors Influencing Primary and Secondary Implant Stability—A Retrospective Cohort Study with 582 Implants in 272 Patients

The success rate of dental implants depends on primary and secondary stability. We investigate predictive factors for future risk stratification models. We retrospectively analyze 272 patients with a total of 582 implants. Implant stability is measured with resonance frequency analysis and evaluated based on the implant stability quotient (ISQ). A linear regression model with regression coefficients (reg. coeff.) and its 95% confidence interval (95% CI) is applied to assess predictive factors for implant stability. Implant diameter (reg. coeff.: 3.28; 95% CI: 1.89–4.66, p < 0.001), implant length (reg. coeff.: 0.67, 95% CI: 0.26–1.08, p < 0.001), and implant localization (maxillary vs. mandibular, reg. coeff.: −7.45, 95% CI: −8.70–(−6.20), p < 0.001) are significant prognostic factors for primary implant stability. An increase in ISQ between insertion and exposure is significantly correlated with healing time (reg. coeff.: 0.11, 95% CI: 0.04–0.19). Patients with maxillary implants have lower ISQ at insertion but show a higher increase in ISQ after insertion than patients with mandibular implants. We observe positive associations between primary implant stability and implant diameter, implant length, and localization (mandibular vs. maxillary). An increase in implant stability between insertion and exposure is significantly correlated with healing time and is higher for maxillary implants. These predictive factors should be further evaluated in prospective cohort studies to develop future preoperative risk-stratification models.

Implant primary stability depending on protocol and insertion mode - an ex vivo study

Background

Dental implant primary stability is thought to be a fundamental prerequisite for the long-term survival and success. The aim of this study was to analyze the influence of protocol and insertion mode on dental implant stability ex vivo. One hundred and twenty implants were inserted either manually or machine-driven into porcine mandibles by a standard or over-dimensioned protocol. Dental implant stability was measured via resonance frequency analysis (RFA), insertion torque (IT), and torque out (TO).

Results

Statistically significant higher IT and TO values were seen after standard protocol insertion (p < 0.05), whereas manual and machine-driven insertion mode showed equivalent values.

Conclusions

The over-dimensioned protocol exceeded the primary stability values recommended for immediate implant insertion; therefore, it could be recommended as well.

Change in the Dominant Side of Chewing as a Serious Factor for Adjusting the Prophylaxis Strategy for Implant-Supported Fixed Dental Prosthesis of Bounded Lateral Defects

OBJECTIVE

 The main purpose of this article is to study the effect of a change in the dominant side of chewing after prosthetics with fixed structures on implants on the main indicators of osseointegration, adaptation to dentures, and the clinical dental status of patients.

MATERIALS AND METHODS

 In a clinical trial, an analysis was made of the adaptation of 64 patients to intraosseous implant-supported fixed dentures and 56 apparently healthy volunteers. The examination complex included determination of the functionally dominant side of chewing, gnathodynamometry and electromyography indicators of masticatory muscles, and radiological osseointegration criteria. The overall treatment outcomes were evaluated using a visual analogue scale and an objective medical questionnaire, "Prognosis of Adaptation to Orthopedic Structures."

RESULTS

 Patients were divided into two subgroups: with a change in the dominant side of chewing after completion of orthopaedic treatment (40 cases) and without a change in the dominant side of chewing (24 cases). In the second subgroup of patients, in contrast to the first subgroup, relatively better indicators of gnathodynamometer and electromyography were observed. So, in the first group, gnathodynamometry indicators on the dominant side were 255.7 N and in the second group 225 N after 9 to 12 months. Electromyography indices amounted to (198.5 μV s) to (166.3 μV s) after 9 to 12 months. Bone density remained at the required level, and overall treatment outcomes were higher. Namely, the compact plate of the alveolar ridge was preserved, and the condition of the bone tissue around the implants testified to stable osseointegration. The participation of surface masticatory muscles in adaptation of patients to intraosseous implant-supported fixed orthopaedic structures and the necessity and importance of changing the dominant chewing side for the general outcomes of orthopaedic treatment have been discussed.

CONCLUSIONS

 It has been established that a change in the functionally dominant chewing side is accompanied by relatively unstable indicators of chewing function, which is combined with increased loads on the installed prostheses during 3 to 6 months of adaptation. This must be taken into account when planning an individual patient adaptation complex for dental orthopaedic structures.

Finite Element Modeling Application in Forensic Practice: A Periprosthetic Femoral Fracture Case Study

The incidence of periprosthetic fractures has rapidly increased in the last two decades and has been the cause of a large number of revision surgeries and permanent physical disability for many patients, as well as a significant socioeconomic burden for many nations. This research deals with a periprosthetic femur fracture real event, occurred following a total hip arthroplasty and treated with one of the most widespread internal fixation methods: the implant of a periprosthetic femur plate system. A Finite Element analysis was performed to investigate the implanted femur plate break after a short follow-up and to understand the plate break causes. Such events are currently object of forensic debate as more and more often hospitals, surgeons, and medical device manufacturers are denounced by patients to whom similar events occur. In this work, different load situations acting on the femur during daily and incidental activities were simulated, in order to validate the correct behavior of the plate, according to the intended use recommended by the manufacturer. The analysis demonstrates that the plate failure can occur in situations of unconventional loading such as that caused by stumbling and in presence of incomplete bone healing.

In Vitro Simulation of Dental Implant Bridges Removal: Influence of Luting Agent and Abutments Geometry on Retrievability

Implant fixed dental prostheses are widely used for the treatment of edentulism, often preferred over the screw-retained ones. However, one of the main features of an implant-supported prosthesis is retrievability, which could be necessary in the case of implant complications. In this study, the retrievability of implant-fixed dental prostheses was investigated considering two of the main factors dental practitioners have to deal with: the abutments geometry and the luting agent. Impulsive forces were applied to dental bridge models to simulate crowns’ retrievability in clinical conditions. The number of impulses and the impulsive force delivered during each test were recorded and used as retrievability indexes. One-hundred-and-five tests were conducted on 21 combinations of bridges and luting agents, and a Kruskal-Wallis test was performed on the results. The abutment geometry significantly influenced the number of impulses needed for retrieval (p < 0.05), and a cement-dependent trend was observed as well. On the other hand, the forces measured during tests showed no clear correlation with bridge retrievability. The best retrievability was obtained with long, slightly tapered abutments and a temporary luting agent.

Dynamics of implant site preparation affecting the quality of osseointegrated implants in the maxillary aesthetic zone

PURPOSE

This study compared piezoelectric (PE) and conventional drills (CD) for maxillary aesthetic zone implant insertion.

MATERIAL AND METHODS

This was a prospective split-mouth study. Implants were divided into two groups. Beds were prepared with CDs in group I and PE in group II. The implant stability quotient (ISQ) of the mechanical implant stability (MIS) was measured intraoperatively. The ISQ of the biological implant stability (BIS) was recorded at postoperative second and fourth months. Marginal bone loss (MBL) and bone density (BMD) were measured in the first and second years after prosthetic loading. The osteotomy time was also documented for both techniques. P values <0.05 were considered significant.

RESULTS

Sixty implants in 30 patients were included. PE provided a significantly higher ISQ. All values were above 70 throughout the follow-up period. The mean of the ISQ for MIS was 63.78 ± 1.03 and 73.89 ± 1.05 in group I and group II, respectively (p = 0.003). PE needed significantly longer osteotomy time with a mean of 11.99 ± 0.839 min. The BIS quality had high stability in group II and medium stability in group I throughout the study period. Its values decreased in both groups. Group II had a lesser percentage of decrease. However, it was significant only at time intervals between intraoperative and two months' postoperative (p = 0.004). MBL and BMD demonstrated insignificant results.

CONCLUSION

The implant site preparation with PE devices should be preferred to CDs whenever possible, because they seem to enhance implant stability and osseointegration, especially at the initial stages of healing.

In Vitro Impact Testing to Simulate Implant-Supported Prosthesis Retrievability in Clinical Practice: Influence of Cement and Abutment Geometry

Cement-retained implant-supported prosthetics are gaining popularity compared to the alternative screw-retained type, a rise that serves to highlight the importance of retrievability. The aim of the present investigation is to determine the influence of luting agent, abutment height and taper angle on the retrievability of abutment–coping cementations. Abutments with different heights and tapers were screwed onto an implant and their cobalt-chrome copings were cemented on the abutments using three different luting agents. The removals were performed by means of Coronaflex^®. The number of impulses and the forces were recorded and analyzed with a Kruskal–Wallis test. Harvard cement needed the highest number of impulses for retrieval, followed by Telio CS and Temp Bond. However, abutment height and taper showed a greater influence on the cap’s retrievability (p < 0.05). Long and tapered abutments provided the highest percentage of good retrievability. The influence of the luting agent and the abutment geometry on the cap’s retrieval performed by Coronaflex^® reflects data from literature about the influence of the same factor on the maximum force reached during uniaxial tensile tests. The impulse force was slightly affected by the same factors.

Overlapping Versus “Kissing” Plates in Femur: A FEM Study

Introduction:

The progressively aging population makes higher the probability of operate fractures in patients who have underwent past long bones fixation. Surgeons may consider not to remove the past implant because of poor bone quality and low life expectancy, but attention must be paid to avoid the origin of new dangerous stresses. There is still a lack of evidence in determining which is the best relation between a plate already implanted in the past and a new fixation device.

Objective:

The purpose of this study was to investigate how the bone-implant stress distribution changes with two different plate configurations: overlapped (the tip of new plate covering part of the old one) versus “kissing” (the tips of the plates in close contact).

This study was based on a finite element analysis by means of Rhinoceros® and Ansys Work bench software programs. In order to reduce confusing factors, the femur was considered to be not fractured.

Materials & Methods:

Different features have been tested: bone quality, plate materials, and plate configurations. The study was conducted by evaluating stress values in different femur sections. The same parameters were evaluated in a femur without plates. Three phases of gait were simulated: Heel-strike, midstance, and toe-off.

Results:

Heel-strike phase has shown to reach the highest stresses. In general, stresses are lower in the overlapping plates configuration when compared to the “kissing” plates one.

Conlusion:

The main evidence shown in this study is that, in silico, the overlapped configuration can decrease the stress under the plates intersection, without increasing the stress shielding.

Modeling ultrasonic wave propagation in a dental implant - Bone system

The evolution of the bone-implant interface reflects the implant osseointegration and bond strength, thereby determining the overall implant stability in the jawbone. Quantitative ultrasound represents a promising alternative technique to characterize the interfacial integrity, precisely due to the fact that those waves propagate essentially along the bone-implant interface, and are therefore influenced by its state. This study reports a numerical investigation of ultrasonic wave propagation for a commercial implant-jawbone system in which the thickness and mechanical properties of the interfacial layer (corresponding to the interphase) are systematically varied through the application of a rule of mixtures, in order to mimic the evolution from a dominantly soft tissue - like medium up to a fully healed bone. A simple figure of merit is devised in terms of an RMS-like (root mean square) factor based on the implant displacements, that evolves continuously and significantly with the bone "healing" process, thereby providing unequivocal information on the nature of the investigated bone-implant interface. The results show that the wave propagation pattern is primarily dictated by the impedance mismatch rather than by the interface thickness. This study validates the concept of quantitative ultrasonic testing as a sensitive alternative to the widespread resonant frequency analysis, thereby opening the way for future sensitivity analyses that will address more refined bone-implant interface pathologies such as those observed in the clinical realm.

Comprehensive Review on Current and Future Regulatory Requirements on Wearable Sensors in Preclinical and Clinical Testing

Medical devices are designed, tested, and placed on the market in a highly regulated environment. Wearable sensors are crucial components of various medical devices: design and validation of wearable sensors, if managed according to international standards, can foster innovation while respecting regulatory requirements. The purpose of this paper is to review the upcoming European Union (EU) Medical Device Regulations 2017/745 and 2017/746, the current and future International Electrotechnical Commission (IEC) and International Organization for Standardization (ISO) standards that set methods for design and validation of medical devices, with a focus on wearable sensors. Risk classification according to the regulation is described. The international standards IEC 62304, IEC 60601, ISO 14971, and ISO 13485 are reviewed to define regulatory restrictions during design, pre-clinical validation and clinical validation of devices that include wearable sensors as crucial components. This paper is not about any specific innovation but it is a toolbox for interpreting current and future regulatory restrictions; an integrated method for design planning, validation and clinical testing is proposed. Application of this method to design wearable sensors should be evaluated in the future in order to assess its potentially positive impact to fostering innovation and to ensure timely development.

Statistical analysis of implant and thread parameters effects on dental implant stability and bone resorption using central composite design method

The effect of dental implant parameters, length and diameter, and thread parameters consisting of thread depth, width, pitch and inner angle on Max von-Mises stress in implant–abutment and cancellous bone is investigated. A three-dimensional finite element model of a threaded dental implant and mandibular segment is built. Face-centered central composite design is applied as the design of experiments method to study and optimize the six independent variable parameters at three levels by applying response surface methodology. The simultaneous analysis of these parameters is run to obtain a better perspective on their effects on responses. The effects of linear, square, and interactive terms on responses through Pareto, main effects, and interaction plots are determined through analysis of variance. A second-order polynomial equation is fitted to the model to predict the response magnitude. The results indicate that implant diameter and its interaction with thread depth are effective in decreasing the likelihood of bone resorption. The implant length affects the Max von-Mises stress in implant–abutment, with no effect on the Max von-Mises stress in cancellous bone. The optimization process caused about 10% and 30% reduction in the magnitude of Max von-Mises stress in implant–abutment and cancellous bone, respectively.

In vitro comparison of resonance frequency analysis devices to evaluate implant stability of narrow diameter implants at varying drilling speeds in dense artificial bone blocks

BACKGROUND

There are no studies that have assessed the implant stability quotient (ISQ) values of narrow diameter implants placed in artificial dense bone blocks at varying drilling speeds (DSs).

PURPOSE

The aim of the present in vitro experiment was to compare the performance of OSSTELL and Penguin devices to evaluate implant stability at DSs of 800 and 2000 rpm.

MATERIALS AND METHODS

A total of 360 osteotomies were created in dense artificial bone blocks at DSs of 800 and 2000 rpm. Dental implants from three manufacturers (group-1: NobelActive implants, Nobel Biocare, Yorba Linda, California; group-2: Zimmer, Eztetic-Zimmer implants, Zimmer Biomet Dental, Palm Beach Gardens, Florida; and group-3: Astra Tech implant system, Dentsply Sirona, York, Pennsylvania) were randomly placed in these osteotomies using an insertion torque of 15 Ncm (60 implants/group). Implant stability in all bone blocks immediately following implant placement was evaluated using the OSSTELL and Penguin devices. ISQ values were presented as means ± SD. Statistical significance was set at P < .05.

RESULTS

There was no significant difference in the ISQ values obtained from the OSSTELL and Penguin devices for implants in groups 1, 2, and 3. There was no significant difference when ISQ values obtained from the OSSTELL device were compared with the Penguin device for narrow diameter dental implants placed in dense bone blocks with osteotomies performed at 800 and 2000 rpm. ISQ values showed statistically significant higher values for OSSTELL compared to Penguin device.

CONCLUSION

The OSSTELL and Penguin devices are reliable for the assessment of implant stability in dense artificial bone. Implant design and site-DS does not seem to have a significant impact of implant stability in artificial dense bone blocks.

Antiseptic sealant and a nanocoated implant-abutment interface improve the results of dental implantation

BACKGROUND

Clinical measures and implant design innovation to improve primary osseointegration and reduce the bacterial contamination of the peri-implant area are intended to reduce the incidence of late inflammatory complications in dental implantation.

PURPOSE

To study the effect of nanostructured coating and antiseptic sealant on the outcomes of dental implantation.

MATERIALS AND METHODS

Ninety-six individuals were clinically supervised. In the first group (Screw Ti + sealant), a special antiseptic sealant matrix was used; the same sealant was used with nanocoated implants in the second group (Nanocoat + sealant), and the conventional treatment protocol was used in the control group (Screw Ti). Patients were evaluated longitudinally during treatment and rehabilitation phases with clinical examinations, radiography, periodontal pathogen detection, and patient experience surveys.

RESULTS

For patients who received a nanocoated implant and an antiseptic sealant (Nanocoat + sealant), relatively better hygienic indices were observed; there was less contamination with periodontal pathogens, bone density remained at the required level, and the overall results of treatment were better.

CONCLUSIONS

Using a matrix for sealing the dental implant-abutment interface with a nanostructured surface provides reliable results regarding stable osseointegration and clinical and patient-reported outcomes of treatment success.

A review on the latest advancements in the non-invasive evaluation/monitoring of dental and trans-femoral implants

Dental implants and transcutaneous prostheses (trans-femoral implants) improve the quality of life of millions of people because they represent the optimal treatments to edentulism and amputation, respectively. The clinical procedures adopted by surgeons to insert these implants are well established. However, there is uncertainty on the outcomes of the post-operation recovery because of the uncertainty associated with the osseointegration process, which is defined as the direct, structural and functional contact between the living bone and the fixture. To guarantee the long-term survivability of dental or trans-femoral implants doctors sometimes implement non-invasive techniques to monitor and evaluate the progress of osseointegration. This may be done by measuring the stability of the fixture or by assessing the quality of the bone-fixture interface. In addition, care providers may need to quantify the structural integrity of the bone-implant system at various moments during the patients recovery. The accuracy of such non-invasive methods reduce recovery and rehabilitation time, and may increase the survival rate of the therapies with undisputable benefits for the patients. This paper provides a comprehensive review of clinically-approved and emerging non-invasive methods to evaluate/monitor the osseointegration of dental and orthopedic implants. A discussion about advantages and limitations of each method is provided based on the outcomes of the cases presented. The review on the emerging technologies covers the developments of the last decade, while the discussion about the clinically approved systems focuses mostly on the latest (2017-2018) findings. At last, the review also provides some suggestions for future researches and developments in the area of implant monitoring.

Biomechanical behaviours of the bone-implant interface: a review

In recent decades, cementless implants have been widely used in clinical practice to replace missing organs, to replace damaged or missing bone tissue or to restore joint functionality. However, there remain risks of failure which may have dramatic consequences. The success of an implant depends on its stability, which is determined by the biomechanical properties of the bone-implant interface (BII). The aim of this review article is to provide more insight on the current state of the art concerning the evolution of the biomechanical properties of the BII as a function of the implant's environment. The main characteristics of the BII and the determinants of implant stability are first introduced. Then, the different mechanical methods that have been employed to derive the macroscopic properties of the BII will be described. The experimental multi-modality approaches used to determine the microscopic biomechanical properties of periprosthetic newly formed bone tissue are also reviewed. Eventually, the influence of the implant's properties, in terms of both surface properties and biomaterials, is investigated. A better understanding of the phenomena occurring at the BII will lead to (i) medical devices that help surgeons to determine an implant's stability and (ii) an improvement in the quality of implants.

Computed tomography for managing periprosthetic femoral fractures. A retrospective analysis

Background

Periprosthetic fractures (PPF) present a common cause for revision surgery after arthroplasty. The choice of performing either an osteosynthesis or revision arthroplasty depends on the orthopedic implant anchored and loosening. Standard diagnostics include x-ray imaging. CT is usually performed to confirm implant loosening in case of ambiguous diagnosis on standard x-ray imaging. This study aimed to examine the role of CT as a diagnostic modality and its implications for treatment planning and outcome.

Methods

Patients treated for PPF from January 2010 to February 2018 were included. X-ray and CT reports were analyzed to assess implant loosening. The planning for surgery and the final surgical treatment were evaluated. In addition, patient characteristics were analyzed and compared between patients with and without additional CT as a preoperative diagnostic procedure.

Results

Seventy-five patients were eligible for the study. X-ray imaging was performed in 90.7% of cases. CT was performed in 60% of the cases as part of the preoperative diagnostic. A clear statement on implant stability or loosening could not be made in 69.1% after X-ray imaging and in 84.4% following CT imaging. Revision arthroplasty for loosened femoral prosthesis components was necessary in 40% of cases. No difference could be determined comparing patients with X-ray imaging to those with X-ray and additional CT. In both groups, operative treatment did not deviate from the preoperative planning.

Discussion

In two thirds of the conventional radiographic findings, no reliable evaluation of implant loosening was possible in femoral PPFs. Intriguingly, additional CT did not improve the evaluation of implant loosening. Nonetheless, CT scans are often performed if loosening assessment is unclear on regular radiographs. This fact can explain the bias CT results in comparison to regular radiography. However, software-supported CT diagnosis could help to adequately answer the question of loosened implants in PPF in the near future. Since the diagnosis of fracture and their morphology assessment is currently adequately performed using X-rays, CT shall not be considered as the gold standard.