Diagnosis of implant stability and its impact on implant survival: a prospective case series study

The relationship between the secondary implant stability quotient and oxidized implant-related factors: A retrospective study

Objective

The present retrospective study aimed to determine the relationship between the secondary implant stability quotient and different parameters related to an oxidized implant.

Methods

A total of 135 patients (305 oxidized implants) were included. Implant-related factors (length, diameter, surgical and loading protocols, grafting, insertion torque, and primary stability) were used for comparisons and linear regression analyses, using secondary ISQ as the dependent variable.

Results

At the patient level, the mean time from implantation to secondary ISQ registration was 20.3 ± 29 weeks, and the mean secondary ISQ was 77.30 ± 7.22. The ISQ did not reveal significant differences regarding implant lengths, loading protocol, and simultaneous grafting. In contrast, platform diameters (3.5, 4.3, and 5.0), surgical protocols (one stage versus two stages), insertion torque (<35 Ncm versus >35 Ncm), and primary stability (achieved versus not achieved) all revealed significant secondary ISQ differences. Nevertheless, the regression analysis demonstrated that the platform diameter was the only variable significantly and positively predicted the secondary ISQ. Similar findings were found with the implant level analysis.

Conclusions

Among different implant- and protocol-related parameters, the platform diameter of the oxidized implant appears to be the only significant predictor of high secondary ISQ values at the time of superstructure connection.

Prospective Randomized Controlled Clinical Trial to Evaluate the Safety and Efficacy of ACTLINK Plasma Treatment for Promoting Osseointegration and Bone Regeneration in Dental Implants

Recent studies have explored surface treatments, such as increasing the hydrophilicity of implant fixtures, to enhance the osseointegration of implants. This prospective clinical study aimed to assess the clinical stability and efficacy of plasma treatment applied to implants with sandblast-acid etching (SLA) surfaces before placement. Twenty-eight patients requiring implant placement provided consent and were assigned randomly to either the SLA group without plasma treatment or the SLA/plasma group with plasma treatment. Recall checks were conducted one and three months after the first-stage surgery, followed by a second surgery at four months. Although no significant differences in buccal bone defects or implant stability were observed between the groups, the SLA/plasma group showed significant increases in marginal bone changes on the mesial and distal sides, as assessed using periapical radiographs. This study underscores the potential of pre-implantation plasma treatment to enhance bone regeneration around implants.

Mandibular overdentures retained by 1 or 2 implants: a 5-year randomized clinical trial on implant stability and peri-implant outcomes

AIM

This is a report of the 5-year results of a two-group parallel randomized clinical trial comparing longitudinal implant stability, and clinical and radiographic peri-implant outcomes of mandibular overdentures retained by one (1-IOD group) or two (2-IOD group) implants.

METHODS

All participants received 4.1 mm diameter tissue-level implants (Straumann® Standard Plus - SLActive®, Institut Straumann AG), installed in the mandible midline (1-IOD; n = 23) or the lateral incisor-canine area bilaterally (2-IOD; n = 24), and loaded after 3 weeks. Implant Stability Quotient (ISQ) was measured using a resonance frequency device (Osstell® Mentor, Integration Diagnostics) at implant placement, after three weeks (loading), and at the 6-month, 1-, 3-, and 5-year follow-ups. Marginal bone loss and clinical implant outcomes (plaque, calculus, suppuration and bleeding) were assessed periodically up to 5 years after loading.

RESULTS

Only minor changes in marginal bone level were observed after 5 years (mean = 0.37; SD = 0.44 mm), and satisfactory and stable peri-implant parameters were observed throughout the 5-year follow-up. No significant differences between groups were found. Overall, the mean primary implant stability was considered high (> 70) for the two groups (1-IOD = 78.1 ± 4.5; 2-IOD = 78.0 ± 5.8). No noticeable changes were observed between implant insertion and loading. A marked increase was observed from insertion to the 6-month follow-up - the mean difference for the 1-IOD group was + 5.5 ± 5.5 (Effect size = 1.00), while for the 2-IOD group, the mean difference was + 6.0 ± 5.6 (Effect size = 1.08). No relevant changes were observed throughout the follow-up periods up to 5 years. Linear mixed-effect model regression showed no influence of the bone-related variables (p > 0.05) and the number of implants (p = 0.087), and a significant effect of the time variable (p < 0.001).

CONCLUSION

Satisfactory peri-implant outcomes and stable secondary stability suggest good clinical performance and successful long-term osseointegration of the implants for single and two-implant mandibular overdentures. Using a single implant to retain a mandibular overdenture does not seem to result in detrimental implant loading over the five years of overdenture use.

CLINICAL RELEVANCE

This study corroborates the use of a single implant to retain a mandibular denture.

Induction of Experimental Peri-Implantitis with Strains Selected from the Human Oral Microbiome

Peri-implantitis (PI), the most widespread condition in the oral cavity, affects patients globally; thus, advanced research in both in vitro and in vivo studies is required. This study aimed to develop peri-implantitis in the rat model by oral contamination with bacteria responsible for PI in humans. The study was carried out in three stages: the extraction of the maxillary first molar to reproduce the human edentation, the mounting of the implant, and finally, the contamination of the device by gavage with Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Streptococcus oralis. The hematological examinations showed statistically significant increases for WBCs (white blood cells), Hb (hemoglobin), RBCs (red blood cells), MCH (mean corpuscular hemoglobin), MCHC (mean corpuscular hemoglobin concentration), and PLTs (platelets), but especially for the level of neutrophils and lymphocytes, and the systemic immunoinflammatory index completed the picture related to the inflammatory response triggered as a result of the activity of microorganisms pathogens on oral tissues. By examining the liver and kidney profile, we hypothesized that peri-implantitis is associated with systemic diseases, and the histopathological examination showed peri-implantitis lesions characterized by a marked inflammatory infiltrate with numerous neutrophils and lymphocytes. By corroborating all the results, we successfully developed a rat peri-implantitis model using a mixed bacterial infection through the oral gavage technique.

Tissue-engineered bone construct promotes early osseointegration of implants with low primary stability in oversized osteotomy

OBJECTIVES

To evaluate the histological parameters and bone mechanical properties around implants with low primary stability (PS) in grafted bone substitutes within an oversized osteotomy.

MATERIALS AND METHODS

An oversized osteotomy penetrating the double cortical bone layers was made on both femora of 24 New Zealand white rabbits. Bilaterally in the femur of all animals, 48 implants were installed, subdivided into four groups, corresponding to four prepared tissue-engineering bone complexes (TEBCs), which were placed between the implant surface and native bone wall: A: tricalcium phosphate β (TCP-β); B: autologous adipose derived-stem cells with TCP-β (ASCs/TCP-β); C: ASCs transfected with the enhanced-GFP gene with TCP-β (EGFP-ASCs/TCP-β); D: ASCs transfected with the BMP-2 gene with TCP-β (BMP2-ASCs/TCP-β). Trichrome fluorescent labeling was conducted. Animals were sacrificed after eight weeks. The trichromatic fluorescent labeling (%TFL), area of new bone (%NB), residual material (%RM), bone-implant contact (%BIC), and the removal torque force (RTF, N/cm) were assessed.

RESULTS

ASCs were successfully isolated from adipose tissue, and the primary ASCs were induced into osteogenic, chondrogenic, and adipogenic differentiation. The BMP-2 overexpression of ASCs sustained for ten days and greatly enhanced the expression of osteopontin (OPN). At eight weeks post-implantation, increased %NB and RTF were found in all groups. The most significant value of %TFL, %BIC and lowest %RM was detected in group D.

CONCLUSION

The low PS implants osseointegrate with considerable new bone in grafted TEBCs within an oversized osteotomy. Applying BMP-2 overexpressing ASCs-based TEBC promoted earlier osseointegration and more solid bone mechanical properties on low PS implants. Bone graft offers a wedging effect for the implant with low PS at placement and promotes osteogenesis on their surface in the healing period.

Radiological Evaluation and Biomechanical Stability of Implants Simultaneously Placed at the Sites with Sole Advanced Platelet-Rich Fibrin (A-PRF) Grafted Sinus Floor

Introduction

In this retrospective study stabilities of 24 implants simultaneously placed at posterior maxillae with sinuses grafted by advanced platelet rich fibrin (A-PRF) and newly formed bone around them were evaluated.

Patient and Methods

Fourteen augmented maxillary sinuses of 11 patients with a mean residual alveolar bone height of 4.55 mm were involved in this study. Maxillary sinus lifting via lateral window approach and implant site osteotomy were performed, and prepared A-PRF clots were used as sole graft material. Each of the implants was immediately placed with a good primary stability. Postoperative sixth month tomography images were compared with preoperative ones in order to calculate the gained bone height and implant stability quotient (ISQ) values were recorded.

Results

The new vertical mean bone height of 24 implant sites was 12.21 mm with an implant survival rate of 100%. ISQ values of the implants were ranging from 62 to 75 with a mean value of 68. Statistically the diameter of implant did not have any effect on new bone formation and the ISQ values, however the length of them did.

Conclusion

A-PRF as a graft material for sinus lifting with simultaneous implant placement is a reliable technique with its low cost and lack of immunogenic reaction risk.

Simultaneous or staged lateral ridge augmentation: A clinical guideline on the decision-making process

Lateral ridge augmentation is a standard surgical procedure that can be performed prior to (staged) or simultaneously with implant placement. The decision between a simultaneous or staged approach involves considering multiple variables. This paper proposed a decision-making process that serves as a guideline for choosing the best treatment choice based on the available evidence and the author's clinical experience.

Evaluation of Implant Stability According to Implant Placement Site and Duration in Elderly Patients: A Prospective Multi-Center Cohort Study

The aim of this prospective study is to investigate implant stability and the reliability of different measuring devices according to implant placement site and duration in patients aged over 65 years. The study evaluated 60 implants (diameter: 3.5/4.0/4.5/5.0 mm and length: 8.5/10.0/11.5 mm) in 60 patients aged ≥ 65 years. The implant placement sites were divided into six evenly distributed sections (n = 10), i.e., maxillary right-posterior, A; maxillary anterior, B; maxillary left-posterior, C; mandibular right-posterior, D; mandibular anterior, E; mandibular left-posterior, F. Participants visited the hospital six times: implant surgery, 1V; stitch removal, 2V; 1-month follow-up, 3V; 2-month follow-up, 4V; before final restoration delivery, 5V; and after final restoration delivery, 6V. The implant stability was evaluated with the Osstell Mentor (ISQ), Periotest M (PTV), and Anycheck (IST). The mean values of ISQ, PTV, and IST were analyzed (α = 0.05). ISQ, PTV, and IST results of 4V and 5V were significantly higher than those of 1V (p < 0.05). The lowest ISQ results occurred in the E location at 4V and 5V (p < 0.05). In all mandibular locations, IST results of 6V were significantly higher than those of 1V, 2V, 3V, and 4V (p < 0.05). ISQ results were negatively correlated with PTV and positively correlated with IST, and PTV was negatively correlated with IST. By considering various factors affecting the stability of the implant, it is necessary to determine the appropriate implant load application time. This could help increase the implant success rate in elderly patients. And as a diagnostic device for implant stability and the evaluation of osseointegration in elderly patients, Anycheck was also able to prove its relative reliability compared to Osstell ISQ Mentor and Periotest M.

A Retrospective Analysis to Assess the Reasons for the Failure of Dental Implants

Background

To assess the reasons for dental implant failures.

Materials and Methods

A total of 100 implants were studied in 80 subjects. The radiographic investigations were performed to assess the record length of implant and diameter of implant. Risk factors, such as habit of smoking, history of diabetes, and hypertension, were recorded. The data were collected and assessed using Statistical Package for the Social Sciences (SPSS) software. The one-way analysis of variance (ANOVA) test was used to assess the failure rate in dental implants. A P-value less than 0.05 was considered statistically significant.

Results

A total of 100 dental implants were included. The maximum dental implant failure was seen with a diameter <3.75 mm (30%) followed by 3.75-4.5 mm (16%) and >4.5 mm (6.15%). The difference was found to be significant (P < 0.05).

Conclusion

Dental implant failure was high in dental implants with <3.75 mm diameter, dental implants with a length <10.0 mm, and among smokers.

Reliability of implant stability measuring devices depending on various clinical conditions: an in vitro study

PURPOSE

The aim of this study was to evaluate the reliability of implant stability measuring devices depending on the location of the implant and the position of the patient.

MATERIALS AND METHODS

Six implants were installed in different dentate sextants of six artificial bone models. Implant stability was measured in three conditions of the bone model (without mounting on a phantom head, mounted on a phantom head in supine position, and mounted on a phantom head in upright position). A resonance frequency analysis device (Osstell) and two damping capacity analysis devices (Periotest and Anycheck) were used to measure implant stability. The values measured outside the phantom head were treated as controls, and the values inside the phantom head were compared using an independent t-test.

RESULTS

Osstell showed different results in two of the six divisions in both the supine and upright positions compared to outside of the mouth (P < .05). Periotest showed different results in all six parts in the supine position and in five parts in the upright position compared to outside of the mouth (P < .05). While Anycheck showed different results in five areas in the supine position compared to outside of the mouth, it showed different results in only one area in the upright position (P < .05).

CONCLUSION

In the difficult implant position for the operator to access, the implant stability measuring devices show less reliability. The accessibility of implant is greatly affected in the order of Osstell, Anycheck, and Periotest.

Randomized clinical study of injectable dextrin-based hydrogel as a carrier of a synthetic bone substitute

OBJECTIVES

This study aimed to improve the performance and mode of administration of a glass-reinforced hydroxyapatite synthetic bone substitute, Bonelike by Biosckin® (BL®), by association with a dextrin-based hydrogel, DEXGEL, to achieve an injectable and moldable device named DEXGEL Bone.

METHODS

Twelve participants requiring pre-molar tooth extraction and implant placement were enrolled in this study. BL® granules (250-500 µm) were administered to 6 randomized participants whereas the other 6 received DEXGEL Bone. After 6 months, a bone biopsy of the grafted area was collected for histological and histomorphometric evaluation, prior to implant placement. The performance of DEXGEL Bone and BL® treatments on alveolar preservation were further analyzed by computed tomography and Hounsfield density analysis. Primary implant stability was analyzed by implant stability coefficient technique.

RESULTS

The healing of defects was free of any local or systemic complications. Both treatments showed good osseointegration with no signs of adverse reaction. DEXGEL Bone exhibited increased granule resorption (p = 0.029) accompanied by a tendency for more new bone ingrowth (although not statistically significant) compared to the BL® group. The addition of DEXGEL to BL® granules did not compromise bone volume or density, being even beneficial for implant primary stability (p = 0.017).

CONCLUSIONS

The hydrogel-reinforced biomaterial exhibited an easier handling, a better defect filling, and benefits in implant stability.

CLINICAL RELEVANCE

This study validates DEXGEL Bone safety and performance as an injectable carrier of granular bone substitutes for alveolar ridge preservation.

TRIAL REGISTRATION

European Databank on Medical Devices (EUDAMED) No. CIV-PT-18-01-02,705; Registo Nacional de Estudos Clínicos, RNEC, No. 30122.

Randomized clinical trial to evaluate the efficacy and safety of two types of sandblasted with large-grit and acid-etched surface implants with different surface roughness

Objectives

This study aims to evaluate the efficacy and safety of two types of sandblasted with large-grit and acid-etched (SLA) surface implants with different surface roughness.

Patients and Methods This study was conducted based on a clinical record review of 55 patients (mean age, 53.00 years). A total of 80 SLA surface implants was placed. Among the 80 implants, 38 implants placed in 29 subjects had surface roughness (Ra) of 3.09 µm (test group, TG), while the other 42 implants placed in 31 subjects had a surface roughness (Ra) of 2.50 µm (control group, CG). A comparison was made of implant primary/secondary stability; success and survival rates; marginal bone loss; and soft tissue assessment including probing pocket depth (PPD), plaque index (PI), gingival index (GI), and bleeding on probing (BOP) between the groups at 1 year after implant placement.

Results

Among the implants that were initially registered, 1 from the TG and 4 from the CG dropped out, leaving 37 implants in the TG and 38 implants in the CG to be traced and analyzed. Although 1 TG case showed unstable primary stability, all cases showed stable secondary stability. Success and survival rates at 1 year after implant placement were 100% in both groups. Marginal bone loss was 0.07 mm and 0.00 mm for the TG and CG, respectively, but the difference was not significant. Among the several parameters for evaluation of soft tissue, the TG showed lower PI at 1 year after implant placement (TG=0.00, CG=0.29; P=0.0004), while the remaining categories showed no significant difference between the groups.

Conclusion

This study shows that the two types of SLA implants with different surface roughness have no difference in efficacy or safety. Therefore, both of the implants can be used safely and with promising outcomes.

Marginal Bone Loss in Internal Conical Connection Implants Placed at the Crestal and Subcrestal Levels before Prosthetic Loading: A Randomized Clinical Study

The vertical position concerning the bone in which the implants are placed has been related as one of the factors causing marginal bone loss. The objective of this study was to evaluate the bone loss that occurs before prosthetic loading around tapered internal connection (CIC) implants placed at the crestal (C) and subcrestal (S) levels. Method: A randomized clinical trial (RCT) was carried out, with a sample size of 62 implants placed in 27 patients who underwent radiological controls on the day of placement, at one month, and at 4 months, and stability was measured by resonance frequency analysis (RFA) on three occasions. Results: Bone loss in implants C and S from the time of placement (T0) and the month after (T1) was not significant (p = 0.54) (C = 0.19 mm and S = 0.15 mm). The difference between one month (T1) and four months (T2) (C = 0.17 mm and S = 0.22 mm) was not significant either (p = 0.26). The difference between the day of placement (T0) and the third and last measurement (T2) was almost null (p = 0.94) (C = 0.35 mm and S = 0.36). The overall success rate of the implants was 97.8%. The stability of the implants measured with RFA went from 70.60 (T0) to 73.16 (T1) and 74.52 (T2). Conclusions: No significant differences were found in the bone loss for implants placed at the C and S levels. The millimeters of bone loss detected in both vertical positions did not have a significant impact on the stability of the implants.

Analysis of acute sinusitis-related early failed implant surface: a combined histological, electron microscopy, and X-ray spectroscopy approach

BACKGROUND

Even though dental implants are a reliable choice for dental rehabilitation, implant failures due to various etiologies have been reported. Early implant failures account for 2 to 6% of installed implants and are reported to have a higher rate than late failures, regardless of loading time. We herein report three cases of acute sinusitis and early implant failure with implants that failed within 1 month after installation. The aim of this study was to evaluate the surface properties of early failed implants and peri-implant tissue to determine the early osseointegration pattern in acute sinusitis-related failed implants as well as the possible role of surface contamination in the failure of osseointegration.

RESULTS

A combined histological, electron microscopy, and X-ray spectroscopy approach was used to characterize the surface of non-osseointegrated titanium implants and the surrounding biological tissues. Morphologic scanning electron microscopy revealed a heterogeneous surface and irregular osseointegration. The implant surface was covered mostly by carbon- and oxygen-rich organic matter. Energy-dispersive X-ray spectroscopy surface analysis of three implants showed the incorporation of some contaminants in both the upper and apical regions. Carbon, nitrogen, sodium, silicon, chlorine, sulfur, gold, and zirconium were detected on the surface of one or more failed implants. Fibrosis, lymphocytic, and macrophage infiltrates and a high activation of osteoclasts surrounding the bone graft particles were detected in the surrounding tissues.

CONCLUSIONS

The etiology and mechanism of early implant failure, especially in sinus-related cases, as well as the proper management interventions to minimize the rate of early implant failures, are of great concern. No matter how confident and accurate the surgeon's operation, there may be unknown errors in the whole procedure that no one knows about. Rather than errors related to the implant surface, it is expected that there were invisible problems during the evaluation of the patient's own unique sinus mucosal inflammation or the operator's own procedure. Furthermore, well-designed researches are necessary to reveal the effect of material-related factors on acute sinus complication and early implant failure.

The impact of deproteinized bovine bone particle size on histological and clinical bone healing outcomes in the augmented sinus: A randomized controlled clinical trial

OBJECTIVE

The effect of different deproteinized bovine bone mineral (DBBM) particle sizes on bone healing in maxillary sinus floor augmentation remains unclear. This study compared the newly formed tissue and angiogenesis-related bone healing after sinus floor augmentation using large or small DBBM particles.

MATERIALS AND METHODS

Overall 32 patients were randomly divided into two groups using either large (1-2 mm) or small (0.25-1 mm) DBBM particles for sinus floor augmentation. After 6 months, the mineralized tissue volume was calculated using micro-computed tomography (micro-CT) analysis. The newly formed tissue composition was histomorphometrically analyzed. Angiogenesis was also examined by means of vascular endothelial growth factor (VEGF) expression. Implant failure and marginal bone loss were measured at a 1-year follow-up. Statistical analysis was performed using independent samples t-test.

RESULTS

Micro-CT analysis demonstrated that grafting with large particles resulted in higher bone volume (6.99 ± 2.72 mm³ , p = 0.002) and Bone Volume/Tissue Volume (0.25 ± 0.1, p = 0.03) compared with small particles (3.76 ± 1.83 mm³ and 0.14 ± 0.13, respectively). Small particles showed higher non-mineralized tissue volume (26.31 mm³ ) compared with large particle group (17.4 ± 5.34 mm³ ) with p = 0.001. The histological data revealed significantly higher area of newly formed bone (32.15% ± 14.04% for the large particle and 15.99% ± 14.12% for the small particle groups, p = 0.004). Likewise, non-mineralized tissue was significantly greater in the small particle group (66.48% ± 20.97%) compared with the large particle group (44.36%, p = 0.016). Moreover, use of large particles resulted in a significantly higher VEGF staining intensity score and VEFG positive cells. No implant failure was recorded in both groups, while no difference was found in terms of marginal bone loss at the 1-year follow-up.

CONCLUSIONS

Sinus floor augmentation using large DBBM particles resulted in more angiogenesis expression, higher bone volume, and new bone formation at 6 months after sinus augmentation. However, clinical outcomes with regards to implant placement were similar in both groups.

Peri-implant bone microstructural analysis and comparison of resonance frequency analysis before prosthetic placement: a retrospective study

Objectives

Fractal analysis is a mathematical method used for the calculation of bone trabeculation and lacunarity. This study aims to evaluate the relationship between resonance frequency analysis (RFA) and fractal dimension (FD) of peri-implant bone to determine the preload stability of implants.

Materials and methods

In this study, the results of the fractal analysis calculated from the resonance frequency analysis results taken in the 3rd month of the patients who underwent 2-stage implant by the same doctor and the radiographs taken in the same session were evaluated. A hundred implants in 20 patients were applied in this study. The implant stability quotient (ISQ) values of the implants and fractal dimension values of the peri-implant bone were calculated.

Results

The findings showed that the ISQ1 (p = 0.008), ISQ2 (p = 0.038), ROI2 (p = 0.013), and ROI3 (p < 0.001) values were statistically significantly higher in men than women. The ISQ1 (p = 0.003), ISQ2 (p = 0.013), ROI1 (p = 0.011), and ROI3 (p < 0.001) of the mandible were statistically higher than the maxilla. The fractal dimension cut-off value to assess prosthetic loading was found 1.198.

Conclusion

Fractal analysis is a non-invasive method that can be used in conjunction with clinical examination in the prosthetic loading decision of implants. It is a valuable parameter that can be used without the need for an extra device when it is necessary to reduce the clinical study time.

Clinical relevance

Calculating the fractal dimension of the peri-implant bone is a practical, economical, and applicable method for clinicians. FD calculated from panoramic radiographs used for diagnosis in routine treatments in clinics where access to the necessary devices for ISQ measurement is not available will contribute to clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-022-04464-3.

The impact of zero insertion torque on flapless immediate implant placement in the maxilla (5 years follow up clinical study)

Introduction: The achievement of good osseointegration in immediate implant placement can occur in the presence adequate primary stability. The insertion torque varies between cases depending on many factors. Aim: To assess clinically the impact of zero insertion torque on the survival of immediate implant placement in the maxilla for more than 5 years follow-up. Methods: A flapless immediate 2018 implants were in the maxilla in non-restorable single rooted teeth osteotomy site. The insertion torque of the implant was measured clinically by an integrated software. Results: The final insertion torque for 42 implants out of 2018 placed in fresh extraction sockets in the maxilla was zero (no primary stability). Their survival rate was 83.3%. Conclusions: The lack of certain conditions during immediate implant surgical installation and healing had the major effects on success. The loss of torque during immediate implant placement to zero may jeopardize the survival of the implants, but it may not be statistically significant with their failure and loss. The implant primary stability is not an absolute prerequisite to osseointegration; however, it may affect the implant survival rate.

Efficacy of bone grafting materials in preserving the alveolar ridge in a canine model

Preservation of the alveolar ridge after tooth extraction is an essential component for ideal implant positioning. Furthermore, preservation of bone around the implant after implant placement is an essential component for implant treatment. We aimed to evaluate the efficacy of bone grafting materials in preserving the alveolar ridge after implant placement. Implants were placed in regenerated bone without grafting material or with beta-tricalcium phosphate, bovine bone substitute, or carbonate apatite transplantation. In all groups, the bone healed and the implants were successfully placed within the bone. No significant differences in insertion torque and implant stability quotient values were found. The amount of bone around the implant 5 weeks after implant placement was significantly reduced in the bovine bone substitute group; however, implants placed in regenerated bone achieved sufficient initial fixation and osseointegration.

The osseointegration and stability of dental implants with different surface treatments in animal models: a network meta-analysis

Dental implants are commonly used to repair missing teeth. The implant surface plays a critical role in promoting osseointegration and implant success. However, little information is available about which implant surface treatment technology best promotes osseointegration and implant stability. The aim of this network meta-analysis was to evaluate the osseointegration and stability of four commonly used dental implants (SLA, SLActive, TiUnite, and Osseotite). The protocol of the current meta-analysis is registered in PROSPERO (International Prospective Register of Systematic Reviews) under the code CRD42020190907 (https://www.crd.york.ac.uk). We conducted a systematic review following PRISMA and Cochrane Recommendations. Medline (PubMed), Cochrane Library, Embase, and the Web of Science databases were searched. Only randomized controlled trials were considered. Twelve studies were included in the current network meta-analysis, eleven studies were included concerning the osseointegration effect and five studies were included for stability analysis (four studies were used to assess both stability and osseointegration). Rank possibility shows that the SLActive surface best promoted bone formation at an early healing stage and TiUnite seemed to be the best surface for overall osseointegration. For stability, TiUnite seemed to be the best surface. The present network meta-analysis showed that the SLActive surface has the potential to promote osseointegration at an early stage. The TiUnite surface had the best effect on osseointegration regarding the overall healing period. The TiUnite surface also had the best effect in stability.

Correlation between Primary, Secondary Stability, Bone Density, Percentage of Vital Bone Formation and Implant Size

BACKGROUND

This study aims to evaluate whether there is a correlation between implant stability, bone density, vital bone formation and implant diameter and length.

METHODS

Ninety patients were enrolled in this study. They underwent a socket preservation procedure with allograft or PRF and after 4 months, a total of 90 implants were placed. CBCT scans were assigned prior to implant placement in order to assess the bone density. During the surgical re-entry, a bone biopsy was harvested with a trephine drill. Immediately after implant insertion, the primary stability was measured. The secondary stability was measured 4 months after implant placement.

RESULTS

Primary stability showed a significant positive linear correlation with bone density (r = 0.471, p < 0.001) as well as with percentage of new bone formation (r = 0.567, p < 0.001). An average significant association of secondary stability with bone density (rs = 0.498, p < 0.001) and percentage of newly formed bone (r = 0.477, p < 0.001) was revealed. The mean values of primary stability in all three implant sizes, regarding the diameter of the implants, were similar (narrow 67.75; standard 66.78; wide 71.21) with no significant difference (p = 0.262). The same tendency was observed for secondary stability (narrow 73.83; standard 75.25; wide 74.93), with no significant difference (p = 0.277).

CONCLUSIONS

The study revealed a high correlation between primary and secondary implant stability, and bone density, as well as with the percentage of vital bone formation. Implant length and diameter revealed no linear correlation with the implant stability.

Non-grafted versus grafted sinus lift procedures for implantation in the atrophic maxilla: a systematic review and meta-analysis of randomized controlled trials

The aim of this systematic review and meta-analysis was to critically evaluate the currently existing clinical evidence on the efficacy of graftless maxillary sinus membrane elevation for implantation in the atrophic posterior maxilla. A search protocol without limitations to November 2020 was followed by two independent researchers. Randomized controlled trials using the lateral window approach for graftless sinus membrane elevation were included. Uncontrolled, retrospective, non-comparative studies, case reports, and experimental studies in animals or cadavers were excluded. The search identified 2777 studies. Critical selection by two independent researchers then led to the inclusion of a total of nine studies. A risk of bias assessment was applied using the revised Cochrane risk-of-bias tool for randomized trials. A meta-analysis was conducted for seven studies. Results showed a high overall implant survival rate in both the graftless and bone-grafted sinus lift groups (97.92% and 98.73%, respectively). The graftless sinus lift group showed a significantly lower vertical bone height gain, with a mean difference of -1.73mm (P=0.01), and a significantly lower bone density, with a mean difference of -94.7 HU (P<0.001). The implant stability quotient values did not differ significantly between the test and control groups (P=0.07).

The influence of implant design on the kinetics of osseointegration and bone anchorage homeostasis

Titanium implants have shown considerable success in terms of achieving quick and long-lasting stability in bone through the process of osseointegration. Further work aims to improve implant success rates by modifying implant design on the nano-, micro-, and macro- scales with the goal of achieving higher levels of bone anchorage more quickly. However, the most frequently used methods of analysis do not investigate bone anchorage as a whole but as a series of discrete points, potentially missing relevant insight which could inform the effects of topography on these 3 scale ranges. Herein we utilize an asymptotic curve fitting method to obtain a biologically relevant description of reverse torque data and compare the anchorage of 12 different implant groups. Implant surface topography had a significant effect on the rate and degree of anchorage achieved during the initial bone formation period of osseointegration but was not found to influence the relative change in anchorage during bony remodeling. Threaded implants significantly decreased the time required to reach peak anchorage compared to non-threaded implants and implants with micro-topographically complex surfaces required greater torque to be removed than implants without such features. Nanotopography increased overall anchorage and decreased the time required to reach peak anchorage but to a lesser degree than microtopography or macrogeometry respectively. The curve fitting method utilized in the present study allows for a more integrated analysis of bone anchorage and permits investigation of osseointegration with respect to time, which may lead to a more targeted approach to implant design.

Effect of leukocyte and platelet rich fibrin (L-PRF) on stability of dental implants. A systematic review and meta-analysis

The aim of this study was to assess the impact, if any, of L-PRF application in an implant bed prior to implant placement, focusing on stability by means of implant stability quotient (ISQ) values. The literature was searched in a systematic way by means of the main databases and hand searching of the most relevant journals. The inclusion and exclusion criteria were used to determine the eligible studies included in this review. Only randomised controlled trials (RCT) and controlled clinical trials (CCT) were included. A total of four RCTs were included for data extraction. The risk of bias was deemed moderate to unclear. Meta-analysis was performed to assess the effect of L-PRF, on implant stability, immediately post-insertion in three studies, after one week from the implant placement in three studies and after four weeks for all the included studies. The fixed effects model has shown Hedges g statistic for the one week varying from 0.380 to 1.401 with a pooled figure of 0.764 (95% CI 0.443 to 1.085) and for four weeks varying between 0.74 and 1.1 with a combined effect of 0.888 (95% CI 0.598 to 1.177). The results for both intervals were in favour of the use of L-PRF while the statistical difference immediately post-insertion was not statistically significant. The present systematic review, though acknowledging its limitations, suggests that L-PRF has a positive effect on secondary implant stability and that needs to be correlated to the clinical practice to measure the actual clinical effect by means of reducing treatment times.

The Effects of Smoking Cigarettes on Immediate Dental Implant Stability—A Prospective Case Series Study

Background: Smoking tobacco significantly affects the biology of periodontal tissues and contributes to the increased risk of peri-implant diseases. The aim of the study was to investigate whether smoking cigarettes affects the primary and secondary stability of maxillary dental implants, inserted into fresh sockets immediately after extraction. Methods: The study was conducted on 164 patients between the ages of 27–71 years old. 67 individuals smoked more than 20 cigarettes daily and 97 were non-smokers. 190 immediate implants were inserted in the maxilla. Immediate implantations were performed with simultaneous augmentation of the socket with xenogenic bone grafting material. In the posterior region, implants were inserted into the palatal alveolus. The stability of the implants was measured using Insertion Torque Value (ITV) and two types of devices: Periotest (PT) and Osstell (ISQ). Marginal bone loss was evaluated on cone beam computed tomography scans. Results: In an aesthetic area, the PT values at 6 months post-implantation were higher for smokers than non-smokers (p < 0.05), respectively. The ISQ values were significantly lower in smokers compared to non-smokers at 6 months post-implantation (p = 0.0226), respectively. In the posterior region PT values were higher in smokers both on the day of implantation (p = 0.0179), 6 months after surgery (p = 0.0003) as well as 24 months after surgery (p < 0.0001), as compared to non-smokers, respectively. Smokers revealed lower ISQ values than non-smokers (p = 0.0047) on the day of implantation, as well as 6 months after implantation (p = 0.0002), respectively. There were no significant differences in marginal bone loss after 18 months of loading between smokers and non-smokers in the aesthetic, as well as posterior regions (p > 0.05). ITV measurements were lower in smokers than non-smokers in the aesthetic (16.3 vs. 17.5 Ncm) and posterior area (16.8 vs. 17.9 Ncm). Conclusions: This study indicate that smoking cigarettes has a negative effect on the stability of immediate implants in the maxilla. Primary stability of immediate implants may be lower in the posterior area of the maxilla in smokers when compared to non-smokers, which may eliminate smokers from immediate implants in this region. Secondary stability of immediate implants may be lower in both the aesthetic and posterior areas in smokers compared to non-smokers, which may encourage the postponement of final crowns delivery at 6 months post op and the extension of the occlusaly temporary crowns use in some smoker cases.

Bone and Cartilage Interfaces With Orthopedic Implants: A Literature Review

The interface between a surgical implant and tissue consists of a complex and dynamic environment characterized by mechanical and biological interactions between the implant and surrounding tissue. The implantation process leads to injury which needs to heal over time and the rapidity of this process as well as the property of restored tissue impact directly the strength of the interface. Bleeding is the first and most relevant step of the healing process because blood provides growth factors and cellular material necessary for tissue repair. Integration of the implants placed in poorly vascularized tissue such as articular cartilage is, therefore, more challenging than compared with the implants placed in well-vascularized tissues such as bone. Bleeding is followed by the establishment of a provisional matrix that is gradually transformed into the native tissue. The ultimate goal of implantation is to obtain a complete integration between the implant and tissue resulting in long-term stability. The stability of the implant has been defined as primary (mechanical) and secondary (biological integration) stability. Successful integration of an implant within the tissue depends on both stabilities and is vital for short- and long-term surgical outcomes. Advances in research aim to improve implant integration resulting in enhanced implant and tissue interface. Numerous methods have been employed to improve the process of modifying both stability types. This review provides a comprehensive discussion of current knowledge regarding implant-tissue interfaces within bone and cartilage as well as novel approaches to strengthen the implant-tissue interface. Furthermore, it gives an insight into the current state-of-art biomechanical testing of the stability of the implants. Current knowledge reveals that the design of the implants closely mimicking the native structure is more likely to become well integrated. The literature provides however several other techniques such as coating with a bioactive compound that will stimulate the integration and successful outcome for the patient.

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.

Marginal Bone Loss in Implants with External Connection versus Internal Conical Connection Prior to Prosthetic Loading. A Randomized Clinical Study

Introduction: The prosthetic connection of implants has been related to the loss of marginal bone. The aim of this study was to evaluate bone loss around external connection (EC) and internal conical connection (ICC) implants prior to prosthetic loading. Material and methods: A randomized clinical trial (RCT) was carried out, with a sample size of 93 implants (31 EC and 62 ICC) placed in 27 patients. Radiological controls were performed and stability was measured by resonance frequency analysis (RFA) on the day of placement, at 1 month and at 4 months after the placement. Results: Bone loss in EC implants was not statistically different than in ICC implants between the time of placement (T0) and the subsequent month (T1): (EC = 0.18 mm and ICC = 0.17 mm). Between one month (T1) and four months (T2): (EC = 0.39 mm and ICC = 0.19 mm) this difference was highly significant (p = 0.00). Bone loss between T0 and T2 was significantly lower in the ICC (EC = 0.57 mm and ICC = 0.36 mm), (p = 0.01). The overall success rate of the implants was 97.8%. The stability of the implants increased from 70.69 (T0) to 73.91 (T1) and 75.32 (T2). Conclusions: ICC showed less bone loss up to the time of prosthesis placement. Such bone loss did not have a significant impact on bone stability. Long term RCTs are needed to demonstrate whether this bone loss, which is more pronounced at the beginning in EC, tends to stabilize and equate to ICC.

Comparison of nonself-tapping tapered implant and self-tapping hybrid implant in terms of implant stability at initial and second fixation: A prospective randomized clinical trial

BACKGROUND

Various features are provided in dental implants to improve initial fixation.

PURPOSE

To compare the implant stability of the nonself-tapping tapered implant and self-tapping hybrid implant over a 3-month healing period.

MATERIALS AND METHODS

A randomized controlled trial was conducted. Patients were randomly divided into tapered and self-tapping groups. Patients in the tapered group received NobelReplace Tapered (Nobel Biocare, Sweden) implants, while those in the self-tapping group received NobelSpeedy (Nobel Biocare, Sweden) implants. Implant stability was measured by resonance frequency analysis at surgery and 3 months following implant insertion. Data were analyzed using an independent t-test.

RESULTS

Forty-three patients (tapered group: 21, self-tapping group: 22) received a total of 88 implants. Initial stability in the tapered group was significantly higher (mean: 60.14, SD: 12.40) than that in the self-tapping group (mean: 54.72, SD: 7.92). Implant stability significantly increased 3 months after implantation in the tapered group (mean: 66.61, SD: 9.00) and self-tapping group (mean: 64.01, SD: 5.78). No significant intergroup difference in implant stability was noted 3 months after surgery.

CONCLUSIONS

The tapered shape affected initial fixation more than the self-tapping function. However, during the second fixation, both implants showed good stability, and the difference disappeared.

A Simplified Prosthetic Implant Loading Protocol: 1-Year Clinical Follow-Up Study

Purpose

To retrospectively investigate the one-year clinical outcome following a standardized treatment protocol for immediate loading. The protocol mandates predefined requirements for implant stability. If fulfilled, immediate loading of the implants is performed with a simplified prosthetic protocol which includes one-time impression at the time of surgery and definitive restoration within eight weeks.

Methods

Twenty-five patients were treated with 48 Neoss ProActive Tapered implants. Minimum primary stability was established before subjecting the implants to immediate nonfunctional load. Definitive prostheses were delivered six to eight weeks from implant placement. Insertion torque (IT), resonance frequency analysis (RFA), intraoral radiographs, and impressions of implant positions were registered at implant placement. During clinical follow-up, RFA was measured at two, four, and six to eight weeks and six months from implant placement to monitor continued implant stability. Marginal bone level measurements were performed at implant placement, six-month, and one-year follow-up visits.

Results

IT was over 40 N·cm for 46 implants. Two implants with IT <30 N·cm were both splinted to another implant with IT >50 N·cm, tightening the retention screw with low forces. No implants were lost during the observation period. Mean RFA measurements remained stable without any decrease during the initial six-month healing phase. Mean marginal bone remodeling was −0.47 ± 0.38 mm from implant placement to 1 year. No significant difference was found for marginal bone remodeling between implants placed in the healed bone or fresh extraction sockets.

Conclusion

Within the limits of this study, it is concluded that using a simplified immediate loading protocol can be predictably applied to reduce the overall treatment time and the number of clinical sessions.

Immediate Placement and Restoration of a New Tapered Implant System in the Aesthetic Region: A Report of Three Cases

Objective

To assess the clinical, radiographic, aesthetic, and patient-centred outcomes of a new implant system applied for an immediate implant placement and restoration approach in single tooth replacement of anterior maxillary teeth. Material and Method. Three cases were treated with a bone level tapered implant. All patients were treated with the same strategy involving flapless extraction and implant placement with simultaneous augmentation. Implants were provisionally restored with a screw-retained restoration at the day of surgery. Definitive restoration was fabricated after 3 months. Follow-up was one year after definitive restoration.

Results

At the 1-year follow-up, the implants were stable and no complications had occurred. Peri-implant bone levels had increased with a mean value of 0.24 ± 0.30 mm between definitive restoration placement and 1 year of follow-up. Clinical outcome scores showed healthy soft tissues. Mean Pink and White Esthetic scores were rated 7.0 and 7.3, respectively. Mean patient satisfaction had improved from 55.7 (pretreatment) to 90.0 (1-year follow-up) on a 0-100 VAS scale.

Conclusion

Immediate implant placement and restoration with the new tapered bone level implant system are accompanied by good initial clinical and radiographic results as well as high patient satisfaction.

Healing at implants installed from ~ 70- to < 10-Ncm insertion torques: an experimental study in dogs

OBJECTIVE

To evaluate histologically the early healing at implants installed with different insertion torques MATERIAL AND METHODS: Three months after the extraction of the mandibular premolars and of the first molars, two implants were installed monolaterally in the premolar and two in the molar regions of the edentulous alveolar ridge of twelve dogs. The recipient sites were prepared using drills of different diameter to obtain insertion torque of different values, i.e., 30 Ncm (control) or ~ 70 Ncm (test) in the premolar region, and < 10 Ncm (test) or ~ 50 Ncm (control) in the molar region. Six animals were euthanized after 4 weeks and six after 8 weeks of healing. Histological analyses were performed, and the Wilcoxon test was applied for statistical analyses.

RESULTS

After 4 weeks of healing, in the premolar region, the new bone in contact with the implant surface was 65.0 ± 4.6% and 53.9 ± 13.5% at the ~ 30-Ncm and ~ 70-Ncm sites, respectively (p = 0.075). In the premolar region, new bone proportions were 51.4 ± 17.0% and 67.3 ± 7.0% at the < 10-Ncm and ~ 50-Ncm sites, respectively (p = 0.046). After 8 weeks of healing, in the premolar region, new bone reached fractions of 77.7 ± 16.2% at the ~ 30-Ncm sites, and 68.3 ± 12.1% at the ~ 70-Ncm sites (p = 0.028). In the molar region, new bone presented proportions of 70.2 ± 6.4% at the < 10-Ncm sites and 76.2 ± 9.4% at the ~ 50-Ncm sites (p = 0.173).

CONCLUSIONS

The insertion torque influenced the osseointegration of implants. Higher values of bone-to-implant contact percentages were registered for insertion torques of ~ 30 Ncm and ~ 50 Ncm. Implants inserted with torque < 10 Ncm became integrated with an optimal osseointegration.

Relationship between Implant Length and Implant Stability of Single-Implant Restorations: A 12-Month Follow-Up Clinical Study

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 long-term evaluation of the prognosis of implants with acid-etched surfaces sandblasted with alumina: a retrospective clinical study

Background

The aim of this study was to evaluate the long-term clinical stability of implants with acid-etched surfaces sandblasted with alumina using retrospective analyses of the survival rate, success rate, primary and secondary stability, complications, and marginal bone loss of the implants.

Methods

Patients who had implants placed (TS III SA, SS II SA, SS III SA, and U III SA) with SA surfaces from Osstem (Osstem Implant Co., Busan, Korea) at the Seoul National University Bundang Hospital, from January 2008 to December 2010 were selected for the study. Patients’ medical records and radiographs (panorama, periapical view) were retrospectively analyzed to investigate sex, age, location of implantation, diameter, and length of the implants, initial and secondary stability, presence of bone grafting, types of bone grafting and membranes, early and delayed complications, marginal bone loss, and implant survival rate.

Results

Ninety-six implants were placed in 45 patients. Five implants were removed during the follow-up period for a total survival rate of 94.8%. There were 14 cases of complications, including 6 cases of early complications and 8 cases of delayed complications. All five implants that failed to survive were included in the early complications. The survival of implants was significantly associated with the occurrence of complications and the absorption of bone greater than 1 mm within 1 year after prosthetic completion. In addition, the absorption of bone greater than 1 mm within 1 year after prosthetic completion was significantly associated with the occurrence of complications, primary stability, and implant placement method. Five cases that failed to survive were all included in the early complications criteria such as infection, failure of initial osseointegration, and early exposure of the fixture.

Conclusions

Of the 96 cases, 5 implants failed resulting in a 94.8% survival rate. The failed implants were all cases of early complications such as infection, failure of initial osseointegration, and early exposure of the fixtures. Peri-implantitis was mostly addressed through conservative and/or surgical treatment and resulted in very low prosthetic complications. Therefore, if preventive measures are taken to minimize initial complications, the results can be very stable.

Bone healing at non-submerged implants installed with different insertion torques: a split-mouth histomorphometric randomized controlled trial

Objectives

To evaluate histomorphometrically the healing at implants installed with standard or very low insertion torque values

Material and methods

Twelve volunteer patients were recruited, and two screw-shaped titanium devices were installed in the distal segments of the mandible using insertion torque values of either < 10 Ncm or ~ 30 Ncm. The implants were left to heal in a non-submerged fashion. After 8 weeks, biopsies were retrieved, and ground sections were prepared for histological evaluation.

Results

Histological slides from 11 patients were available for (n = 11). The new bone in contact with the implant surface was 39.3 ± 18.5% and 49.4 ± 9.4% at the < 10 and ~ 30 Ncm sites, respectively. Considering the pre-existing old bone, the total mineralized bone was 46.8 ± 22.1% at the < 10 Ncm sites and 57.0 ± 14.1% at the ~ 30 Ncm. No statistically significant differences were found.

New bone density and total mineralized bone density were 36.6 ± 8.1% and 53.0 ± 13.5% at the < 10 Ncm sites and 35.9 ± 10.0% and 52.2 ± 16.0% at the ~ 30 Ncm sites, respectively. No statistically significant differences were disclosed.

Conclusion

From the data of the present study, it can be concluded that a trend of higher osseointegration was observed at the ~ 30 Ncm compared to the < 10 Ncm torque group. Nevertheless, it can be concluded that an implant installed with a very low torque may achieve a good integration.

Trial registration

ClinicalTrials.gov NCT04017156; trial retrospectively registered on 12 July 2019.

Evaluation of the relationship between Periotest values, marginal bone loss, and stability of single dental implants: A 3-year prospective study

STATEMENT OF PROBLEM

Although the Periotest has been shown to provide reliable information about initial implant stability, whether Periotest values (PTVs) can be correlated with the stability of implants in function for several years is unclear.

PURPOSE

The purpose of this prospective clinical study was to investigate implant stability by using PTVs, as well as changes in stability and peri-implant marginal bone levels (as measured by radiographs) over a 3-year follow-up period. The exploratory hypothesis was that there is a significant correlation between PTVs and bone loss around the implant and that PTVs can provide predictive information about marginal bone-level changes and implant stability over time.

MATERIAL AND METHODS

The study population included patients who needed single-tooth replacement with restoration of cemented fixed partial dentures. Clinical data, PTVs, and periapical radiographs were collected at the time points of implant placement, 3 to 6 months after insertion, and 1 year, 2 years, and 3 years after the final definitive prosthetic restoration. Pearson correlation coefficient tests were performed to estimate the correlation between the PTVs received at the first follow-up time point and the subsequent PTVs received during the follow-up period (up to 3 years after the restoration). The Pearson test was applied, as well as the t test and repeated-measures ANOVA, to evaluate PTVs and bone loss changes over time. The Pearson test was also applied to estimate the correlation between the bone loss values measured at the first follow-up visit and the subsequent bone loss values at the annual follow-up time points (up to and including 3 years after the restoration).

RESULTS

A total of 43 implants were inserted in 34 patients (26 men and 8 women); the average patient age was 52.8 years. A significant reduction in implant stability was detected between implant insertion and the 3- to 6-month follow-up time point, which was then followed by a significant increase in stability at the 1-year follow-up time point and then stabilized during the 2- and 3-year follow-up time points (P<.014). Furthermore, a significant correlation was found between PTVs at the 1-year follow-up and the PTVs at all measured follow-up time points (P<.05). A positive correlation was obtained with high-strength correlation coefficient R (R>0.7) at all follow-up time points. Bone loss changes during the follow-up time points were significantly different and correlated with PTVs (P<.001).

CONCLUSIONS

The Periotest is a reliable device for assessing implant stability and providing predictive information about marginal bone level changes around an implant.

Early implant failure: a retrospective analysis of contributing factors

Purpose

The aim of this retrospective study was to determine the prevalence of early implant failure using a single implant system and to identify the factors contributing to early implant failure.

Methods

Patients who received implant treatment with a single implant system (Luna^®, Shinhung, Seoul, Korea) at Dankook University Dental Hospital from 2015 to 2017 were enrolled. The following data were collected for analysis: sex and age of the patient, seniority of the surgeon, diameter and length of the implant, position in the dental arch, access approach for sinus-floor elevation, and type of guided bone regeneration (GBR) procedure. The effect of each predictor was evaluated using the crude hazard ratio and the adjusted hazard ratio (aHR) in univariate and multivariate Cox regression analyses, respectively.

Results

This study analyzed 1,031 implants in 409 patients, who comprised 169 females and 240 males with a median age of 54 years (interquartile range [IQR], 47–61 years) and were followed up for a median of 7.2 months (IQR, 5.6–9.9 months) after implant placement. Thirty-five implants were removed prior to final prosthesis delivery, and the cumulative survival rate in the early phase at the implant level was 95.6%. Multivariate regression analysis revealed that seniority of the surgeon (residents: aHR=2.86; 95% confidence interval [CI], 1.37–5.94) and the jaw in which the implant was placed (mandible: aHR=2.31; 95% CI, 1.12–4.76) exerted statistically significant effects on early implant failure after adjusting for sex, age, dimensions of the implant, and type of GBR procedure (preoperative and/or simultaneous) (P<0.05).

Conclusions

Prospective studies are warranted to further elucidate the factors contributing to early implant failure. In the meantime, surgeons should receive appropriate training and carefully select the bone bed in order to minimize the risk of early implant failure.

Clinical assessment of the palatal alveolar bone thickness and its correlation with the buccolingual angulation of maxillary incisors for immediate implant placement

BACKGROUND

Clinicians needed to be aware of the thinness of the palatal bone plate when identifying severe protrusion of maxillary incisors, as this could result in perforation of the palatal bone plate during surgical procedures associated with immediate maxillary implant placement.

PURPOSE

This study evaluated the thickness of the palatal bone plate, the buccolingual angulation of maxillary incisors, and the correlation between these two parameters in relation to immediate implant placement.

MATERIALS AND METHODS

Cone-beam computed tomography images of 37 Asian patients (20-60 years old) with no evidence of dental treatment in the maxillary incisor area were collected and classified into groups based on sex and incisor locations. Sagittal slices were used to measure the palatal bone plate thickness at the cervical, middle, and apical levels, and the buccolingual angulation of each tooth was also measured. The intraclass correlation, Shapiro-Wilk test, descriptive analysis, Student's t-test, and Pearson correlation were used for statistical and correlation analyses, with P < .05 applied as the criterion for statistical significance.

RESULTS

At the apical level of all inspected teeth and the middle level of lateral incisors, the palatal bone was significantly thicker in males than in females. The inclination of the maxillary lateral incisor showed a moderate negative linear correlation with the palatal bone thickness at the apical level (R = -0.517 and R = -0.579 for males and females, respectively).

CONCLUSIONS

In an Asian population, an increased buccolingual angulation of the maxillary lateral incisors was correlated with a thinner palatal bone plate at the apical level.

Immediate Loading of Unsplinted Implant Retained Mandibular Overdenture: A Randomized Controlled Clinical Study

This clinical study aimed to clinically and radiographically compare the implant survival rate and peri-implant tissue response between immediate and delayed loading protocols for unsplinted implant retained mandibular overdentures. Twenty patients were enrolled to participate in this study. Each subject was randomly assigned to 1 of 2 treatment groups: test group patients' implants (n = 10), which were immediately loaded, and control group patients' implants (n = 10), which were conventionally loaded. Locator abutments were torqued to 15 Ncm at delivery. Attachments were picked up intraorally immediately after implant placement for the test group and at 3 months for the control group, and 3-lb retention inserts were placed. Marginal bone levels based on cone beam computed tomography fixed reference points were recorded at baseline and 12 months. Modified plaque index, gingival index, and implant stability quotients were recorded at baseline, 3 months, and 12 months. After 12 months, implant survival rate was 100% in both groups. Marginal bone levels, keratinized mucosa, modified plaque index, and gingival index were significantly different among the groups at 3- and 12-month intervals, whereas no significant differences were found in implant stability quotients between the groups. The fact that implant survival rate was 100% in both treatment groups suggests that, within the limitations of this study, immediate loading protocol for unsplinted implant retained mandibular complete overdenture is as predictable, safe, and successful as the delayed loading protocol. Implementing the immediate loading protocol for mandibular implant retained overdentures could shorten treatment time, which could lead to better patient's satisfaction.

Autologous Fibrin Glue With Collagen Carrier During Maxillary Sinus Lift Procedure

This study aimed to describe the use of autologous fibrin glue (AFG) with a collagen carrier during maxillary sinus lift procedures with immediate implants during 3 years of follow-up. Twelve patients who had lost their teeth in the region associated to maxillary sinus, with a bone remnant 3 to 5 mm in height, were selected to perform a maxillary sinus augmentation with AFG and collagen membrane, placing the implant immediately. After 5 months, the implants were connected and rehabilitated. The patients were followed-up for a 3-year period, being evaluated every 6 months. At the end of the 3-year follow-up period, 100% implant success was observed, with a mean of bone augmentation of 7.75 mm. Three maxillary sinus membranes were perforated and healed by using AFG and collagen membrane without identify any complication during the follow-up period. Finally, the use of collagen carrier combined with AFG as a filling material during the maxillary sinus lift procedure may be a low-cost and reliable alternative that allows bone formation.

Can Osseointegration Be Achieved Without Primary Stability?

The osseointegration and survival of dental implants are linked to primary stability. Good primary stability relies on the mechanical friction between implant surface and surrounding bone with absence of mobility in the osteotomy site immediately after implant placement. Several factors have been found to affect implant primary stability, including bone density, implant design, and surgical technique. Various methods have been used to assess implant primary stability including insertion torque and resonance frequency analysis. This article aims to evaluate the success of osseointegration in the absence of primary stability and to propose recommendations to manage implants that lack primary stability.

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

Aims and Objective:

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

Materials and Methods:

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

Results:

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

Conclusion:

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

The Effects of Defect Type and Depth, and Measurement Direction on the Implant Stability Quotient Value

The purpose of this study was to evaluate the effect of defect type and depth as well as measurement direction on implant stability in an ex vivo peri-implant bovine rib bone model. Six kinds of defects (3-wall 2.5 mm, 3-wall 5 mm, 1-wall 2.5 mm, 1-wall 5 mm, circumferential 2.5 mm, circumferential 5 mm), and control (no defect) were prepared in 14 bovine rib bones. A total of 84 defects and 14 controls were created. The same type and size of implants (4 × 10 mm) were placed in each group. The thickness of cortical bone and the insertion torque were measured for each defect, and the implant stability quotient (ISQ) value was measured 3 times from 4 different directions. The thickness of cortical bone ranged from 2.71-3.18 mm. Insertion torque decreased as the defect size increased. As the defect size for the same defect depth increased, the ISQ value decreased (P < .001). There were significant differences between the ISQ values obtained with different measurement directions only between the control and 3-wall 5 mm defect (P < .0001). The ISQ value opposite to the defect direction was higher than that in the defect direction in all 3 directions of the 3-wall and 1-wall 5 mm defects. ISQ values were influenced by defect type and depth. Loss of cortical bone reduced the stability of implants and reduced the ISQ value. Measurement direction also influenced ISQ values.

Primary stability of implants with peri-implant bone defects of various widths: an in vitro investigation

Purpose

This study aimed to evaluate the effects of i) the extent of peri-implant bone defects and ii) the application of bone cement on implant stability with respect to the measurement direction.

Methods

In 10 bovine rib bones, 4 implant osteotomies with peri-implant bone defects of various widths were prepared: i) no defect (D0), ii) a 2-mm-wide defect (D2), iii) a 4-mm-wide defect (D4), and iv) a 8-mm-wide defect (D8). The height of all defects was 10 mm. Implant stability quotient (ISQ) values and Periotest values (PTVs) were measured after implant placement and bone cement application.

Results

With increasing defect width, decreased ISQs and increased PTVs were observed. Statistically significant differences were found between groups D0 and D8, D0 and D4, and D2 and D8. Prior to bone cement application, inconsistent PTVs were found in group D8 depending on the measurement direction. Bone cement increased the implant stability.

Conclusion

Peri-implant bone deficits measuring around 50% of the implant surface compromised implant stability. Clinically, PTVs should be cautiously interpreted in implants with large peri-implant defects due to inconsistent recordings with respect to the measurement direction.

Resonance Frequency Analysis of Tapered Implants Placed at Maxillary Posterior Sites After Lateral Sinus Augmentation: A 1.5-year Follow-Up Prospective Study

OBJECTIVES

To use resonance frequency analysis to evaluate tapered implants placed at maxillary posterior sites after lateral sinus augmentation.

MATERIALS AND METHODS

Patients who had missing teeth in the maxillary posterior area and required lateral sinus augmentation before implant placement were enrolled in this study. After a 6-month healing period, a tapered implant (Osstem TSIV) was placed. Implant success rate, survival rate, and marginal bone loss of the implants were measured. For resonance frequency analysis, implant stability quotient (ISQ) values were measured at each visit during a 1.5-year follow-up period.

RESULTS

Twenty-four patients completed the study procedure. The residual bone height was 2.57 ± 1.10 mm (mean ± SD). Healing of the grafted area was uneventful in all cases, and 55 tapered implants were installed. The implant success rate was 95.56%, and the survival rate was 100% throughout the observation period. The marginal bone loss was limited to 0.22 ± 0.44 mm. ISQ increased gradually from 68.40 ± 11.14 to 82.24 ± 4.75 during the 1.5-year follow-up period.

CONCLUSION

The tapered implants showed good initial and final stability after placement in the soft bone of the maxillary posterior area after lateral sinus augmentation.

[Factors affecting osteointegration and the use of early functional load to reduce the duration of treatment in dental implantation]

The article presents literature data on the impact of the surface and shape of dental implants and early functional load with aesthetic and functional rehabilitation on osteointegration and stability of implants at various implantation terms.