Evaluation of the implant stability and the marginal bone level changes during the first three months of dental implant healing process: A prospective clinical study

Computer Aided Full Arch Restoration by Means of One-Piece Implants and Stackable Guide: A Technical Note

This technical note aims to present a recently developed computer-guided protocol characterized by titanium-reinforced stackable surgical guides during post-extractive implant placement and subsequent immediate loading. A full maxillary edentulism was rehabilitated with one-piece implants, starting from a pre-existing removable denture. 3D digital scans of the removable denture and upper and lower arches were performed. On this basis, a prototype with ideal esthetic and functional outcomes was realized and replicated into a custom-made radiological stent with markers. The superimposition of STL and DICOM files allowed virtual planning of one-piece implants in the ideal prosthetically driven position. The stackable guides, composed of a fixed base template and additional removable components, were then realized. The fixed template, initially secured with anchor pins to the bone, was no longer removed. The removable components, which were screwed to the base template, were used to perform implant surgery and immediate prosthetic loading. No surgical complications occurred, the implants achieved a minimum insertion torque of 35 Ncm, and immediate prosthetic loading was performed. The base template allowed for the maintenance of a fixed reference during the entire workflow, improving the transition between the digital project, the surgical procedure, and the prosthetic rehabilitation.

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.

Effect of implant diameter and cantilever length on the marginal bone height changes and stability of implants supporting screw retained prostheses: A randomized double blinded control trial

PURPOSE

This randomized controlled trial aimed to evaluate the effect of implants' two different diameters and cantilever lengths on the marginal bone loss and stability of mplants supporting maxillary prostheses.

MATERIALS AND METHODS

Ninety-six implants were placed in sixteen completely edentulous maxillary ridges. Patients were randomly divided into two groups: Group A, implants were placed with a cantilever to anterior-posterior AP spread length (CL:AP) at a ratio of 1:3; Group B, implants were placed with a CL:AP at a ratio of 1:2. Patients were further divided into four sub-groups: Groups A1, A2, B1, and B2. Groups A1 and B1 received small diameter implants while Groups A2 and B2 received standard diameter implants. Bone height and stability measurements around each implant were performed at 0, 4, 8 and 24 months after definitive prostheses delivery.

RESULTS

Statistical analysis of the mean implant stability and height values revealed an insignificant difference between Group A1 and Group A2 at all the different time intervals while significantly higher values in Group B1 in comparison with Group B2. Results also showed significantly higher values in Group A1 in comparison with Group B1 and an insignificant difference between Group A2 and Group B2 at all the different time intervals.

CONCLUSION

It can be concluded that the use of small diameter implants placed with a CL:AP at a ratio of 1:3 provided predictable results and that the 1:2 CL:AP significantly induced more critical bone loss in the small diameter implants group, which can significantly reduce long term success and survival of implants.

Comparative evaluation of implant stability and crestal bone level between tapered and cylindrical implants in the posterior regions of the mandible: A prospective, randomized, split-mouth clinical trial

Purpose

To compare the clinical outcome of tapered and cylindrical implants placed in the posterior region of mandible by measuring implant stability and crestal bone level at the healing period.

Materials and Methods

A prospective clinical study was conducted on 15 patients who were included in the study based on the inclusion and exclusion criteria. A total of 30 dental implants were placed in both groups: 15 implants in Group I (tapered implants) and 15 implants in Group II (cylindrical implants) in the posterior region of mandible. Implant stability assessment by periotest was done at the time of implant placement (baseline) and after 3 months. The crestal bone level was measured with the help of radiovisiography (RVG) at the time of implant placement (baseline) and at 3 and 6 months.

Results

At baseline, there was statistically significant (P < 0.01) difference in primary implant stability. Tapered implants had higher primary implant stability than cylindrical implants. However, at 3 months, there was no statistically significant (P > 0.05) difference in the secondary implant stability of both the groups. Also, the crestal bone level on the mesial and distal sides of dental implant for tapered and cylindrical implants was statistically nonsignificant (P > 0.05) at all time intervals, that is, at baseline and at 3 and 6 months.

Conclusion

Tapered implants had higher primary stability than cylindrical implants, and no difference was found in secondary stability. The crestal bone level was similar for both groups during early healing and early post-loading periods.

Clinical study to assess influence of immediate provisionalization and various implant morphologies on implant stability: A prospective clinical study

Introduction

The aim of this study was to evaluate the influence of different implant morphologies and immediate provisionalization options on the change of implant stability.

Methods

94 Patients were randomized to receive implants from Straumann^® BL/Straumann^® BLT/Astra OsseoSpeed^® TX, meanwhile having the same opportunity to receive healing abutment or immediate provisionalization. Implant stability quotient (ISQ) and marginal bone loss (MBL) were recorded at following timepoints. Parametric statistic was used for data analysis.

Results

Data showed that ISQ and MBL values of conical/straight/straight with micro-thread neck implants had no significant difference.

Discussion

Immediate provisionalization options could move the dip point of ISQ values ahead or delayed around one week, which were also relevant to implant systems. MBL values were proved to be unaffected by both two factors mentioned above.

Biomechanical performance of Ti-PEEK dental implants in bone: An in-silico analysis

Stress-shielding is caused by a significant mismatch in stiffness between bone tissue and Ti alloy dental implants. Therefore, in this study, a Ti-PEEK composite implant was examined and compared with conventional titanium, to determine the behavior of the host bone. Twelve 3D finite element models were modeled with two conditions of marginal cortical bone (with and without marginal bone loss). Six implant designs were constructed. Implant (A) was made with a conventional design (dense titanium), implants (B), (C) and (D) are designed with Ti-PEEK composite (outer layer made of PEEK and inner structures made of Ti with hexagonal, cylindrical, and cross shapes for implants (B), (C) and (D), respectively), the implant (E) is designed with Ti at the upper half section and PEEK at the bottom half section, and the implant (F) is designed with PEEK at the upper half section and Ti at the bottom half section. An axial load of 200 N was applied to the buccal cusp and central fossa of the occlusal surface. The displacements, stress, and equivalent strain were analyzed at the level of bone tissue. The mechanostat of Frost was used to determine the behavior of the cancellous bone under these biomechanical conditions. Results showed that strains were greater in cancellous bone with marginal bone loss than in healthy bone (w/o MBL). When compared to implants (B)-(F), conventional implant (A) did not produce as much strain. Thus, results and analyses suggest that the Ti-PEEK implants outperform compared with the implant (A) in the case of no marginal bone loss. However, the implants (A) and (E) perform equally in terms of bone loss.

Effect of the Size of Titanium Particles Released from Dental Implants on Immunological Response

The techniques used in oral implantology to remove bacterial biofilm from the surface of implants by machining the titanium surface (implantoplasty) or by placing rough dental implants through friction with the cortical bone generate a large release of particles. In this work, we performed a simulation of particle generation following clinical protocols. The particles were characterized for commercially pure titanium with particle sizes of 5, 10, 15, and 30 μm. The aim was to determine the effect of particle size and chemical composition of the implant on the immune response. For this purpose, their morphology and possible contamination were characterized by scanning electron microscopy and X-ray microanalysis. In addition, the granulometry, specific surface area, release of metal ions into the medium, and studies of cytocompatibility, gene expression, and cytokine release linked to the inflammatory process were studied. The release of ions for titanium particles showed levels below 800 ppb for all sizes. Smaller particle sizes showed less cytotoxicity, although particles of 15 μm presented higher levels of cytocompatibility. In addition, inflammatory markers (TNFα and Il-1β) were higher compared to larger titanium. Specifically, particles of 15 μm presented a lower proinflammatory and higher anti-inflammatory response as characterized by gene expression and cytokine release, compared to control or smaller particles. Therefore, in general, there is a greater tendency for smaller particles to produce greater toxicity and a greater proinflammatory response.

Analysis of Biomarkers and Marginal Bone Loss in Platform-Switched and Nonplatform-Switched Implants: A Randomized Clinical Trial

Objectives. To compare the peri-implant crevicular fluid (PICF) biomarker levels, peri-implant status, and marginal bone level (MBL) differences of implants restored with randomly assigned nonplatform-switched (NPS) or platform-switched (PS) abutments. Methods. Ninety-four implants in 27 subjects were included in this study. Receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1) levels in PICF, peri-implant health, and the change in the MBL were evaluated at the time of restoration ( $T_1$ ) and after 12 months ( $T_2$ ). Results. The IL-1β levels decreased and the RANKL, OPG, and MCP-1 levels increased from $T_1$ to $T_2$ ( $P<0.05$ ) in both groups. RANKL/OPG ratio at $T_1$ , MCP-1 levels at $T_2$ , and the MCP-1 change from $T_1$ to $T_2$ were lower in the PS group than in the NPS group ( $P<0.05$ ). MBL change was lower ( $0.51\pm 0.31$  mm) in the PS group than that ( $0.75\pm 0.29$  mm) in the NPS group at $T_2$ ( $P<0.001$ ). Peri-implant health status between the study groups was negligible. Conclusion. PS was superior to NPS regarding the preservation of MBL. Higher MCP-1 levels, altered RANKL/OPG ratio, and lower OPG levels in the NPS group could be associated with subclinical peri-implant bone remodeling.

Multidisciplinary Approach for Full-Mouth Rehabilitation of a Young Adult Patient with Ameloblastoma

Ameloblastoma is a benign but locally invasive neoplasm of the odontogenic epithelium that tends to grow slowly in the mandible or maxilla. It can be highly destructive to the surrounding dental anatomy and can cause death by progressive spread to nearby vital structures in rare cases. Marginal resection is the most effective method of eliminating the tumor, but treatment can further contribute to oral and dental deformity and malfunction. This clinical report describes the dental rehabilitation of a young adult patient diagnosed with ameloblastoma and underwent preliminary marsupialization, segmental mandibulectomy, and fibula free flap reconstruction, followed by mandibular dental implant placements. Orthodontic and rapid palatal expansion for maxillary arch correction was also performed. The treatment goal of regaining dental function and a satisfactory appearance was accomplished.

Effect of Platelet Concentrates on Marginal Bone Loss of Immediate Implant Procedures: A Systematic Review and Meta-Analysis

BACKGROUND

To evaluate marginal bone loss (MBL) in immediate implant procedures (IIP) placed in conjunction with platelet concentrates (PCs) compared to IIP without PCs.

METHODS

A search was performed in four databases. Clinical trials evaluating MBL of IIP placed with and without PCs were included. The random effects model was conducted for meta-analysis.

RESULTS

Eight clinical trials that evaluated MBL in millimeters were included. A total of 148 patients and 232 immediate implants were evaluated. The meta-analysis showed a statistically significant reduction on MBL of IIP placed with PCs when compared to the non-PCs group at 6 months (p < 0.00001) and 12 months (p < 0.00001) follow-ups. No statistically significant differences were observed on MBL of IIP when compared PCs + bone graft group vs. only bone grafting at 6 months (p = 0.51), and a significant higher MBL of IIP placed with PCs + bone graft when compared to only bone grafting at 12 months was found (p = 0.03).

CONCLUSIONS

MBL of IIP at 6 and 12 months follow-ups is lower when PCs are applied in comparison to not placing PCs, which may lead to more predictable implant treatments in the medium term. However, MBL seems not to diminish when PCs + bone graft are applied when compared to only bone grafting.

Small blood stem cells for enhancing early osseointegration formation on dental implants: a human phase I safety study

Background

Small blood stem cells (SB cells), isolated from human peripheral blood, demonstrated the ability to benefit bone regeneration and osseointegration. The primary goal of our study is to examine the safety and tolerability of SB cells in dental implantation for human patients with severe bone defects.

Methods

Nine patients were enrolled and divided into three groups with SB cell treatment doses of 1 × 10⁵, 1 × 10⁶, and 1 × 10⁷ SB cells, and then evaluated by computed tomography (CT) scans to assess bone mineral density (BMD) by Hounsfield units (HU) scoring. Testing was conducted before treatment and on weeks 4, 6, 8, and 12 post dental implantation. Blood and comprehensive chemistry panel testing were also performed.

Results

No severe adverse effects were observed for up to 6-month trial. Grade 1 leukocytosis, anemia, and elevated liver function were observed, but related with the patient’s condition or the implant treatment itself and not the transplantation of SB cells. The levels of cytokines and chemokines were detected by a multiplex immunological assay. Elevated levels of eotaxin, FGF2, MCP-1, MDC, and IL17a were found among patients who received SB cell treatment. This observation suggested SB cells triggered cytokines and chemokines for local tissue repair. To ensure the efficacy of SB cells in dental implantation, the BMD and maximum stresses via stress analysis model were measured through CT scanning. All patients who suffered from severe bone defect showed improvement from D3 level to D1 or D2 level. The HU score acceleration can be observed by week 2 after guided bone regeneration (GBR) and prior to dental implantation.

Conclusions

This phase I study shows that treatment of SB cells for dental implantation is well tolerated with no major adverse effects. The use of SB cells for accelerating the osseointegration in high-risk dental implant patients warrants further phase II studies.

Trial registration

Taiwan Clinical Trial Registry (SB-GBR001) and clinical trial registry of the United States (NCT04451486).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02461-z.

Mechanical Evaluation of the Stability of One or Two Miniscrews under Loading on Synthetic Bone

The aim of the present study was to evaluate the primary stability of a two-miniscrew system inserted into a synthetic bone and to compare the system with the traditional one. Forty-five bi-layered polyurethane blocks were used to simulate maxillary cancellous and cortical bone densities. Samples were randomly assigned to three groups—one-miniscrew system (Group A, N = 23), two-miniscrew system (Group B, N = 22) and archwire-only (Group C, N = 10). A total of 67 new miniscrews were subdivided into Group A (23 singles) and Group B (22 couples). 30 mm of 19″ × 25″ archwires were tied to the miniscrew. The load was applied perpendicularly to the archwire. Maximum Load Value (MLV), Yield Load (YL) and Loosening Load (LL) were recorded for each group. The YL of Group B and C had a mean value respectively of 4.189 ± 0.390 N and 3.652 ± 0.064 N. The MLV of Group A, B and C had a mean value respectively of 1.871 ± 0.318N, of 4.843 ± 0.515 N and 4.150 ± 0.086 N. The LL of Group A and B had a mean value respectively of 1.871 ± 0.318 N and of 2.294 ± 0.333 N. A two- temporary anchorage device (TAD) system is on average stiffer than a one-TAD system under orthodontic loading.

Relationship between Implant Geometry and Primary Stability in Different Bony Defects and Variant Bone Densities: An In Vitro Study

AIM

This in vitro study aimed to evaluate the effects of implant designs on primary stability in different bone densities and bony defects.

METHODS

Five implant types (tapered-tissue-level, tissue-level, zirconia-tissue-level, bone-level, and BLX implants) were used in this assessment. The implants were inserted into four different artificial bone blocks representing varying bone-density groups: D1, D2, D3, and D4. Aside from the control group, three different types of defects were prepared. Using resonance frequency analysis and torque-in and -out values, the primary stability of each implant was evaluated.

RESULTS

With an increased defect size, all implant types presented reduced implant stability values measured by the implant stability quotient (ISQ) values. Loss of stability was the most pronounced around circular defects. Zirconia and bone-level implants showed the highest ISQ values, whereas tissue level titanium implants presented the lowest stability parameters. The implant insertion without any thread cut led to a small improvement in primary implant stability in all bone densities.

CONCLUSIONS

Compared with implants with no peri-implant defects, the three-wall and one-wall defect usually did not provide significant loss of primary stability. A significant loss of stability should be expected when inserting implants into circular defects. Implants with a more aggressive thread distance could increase primary stability.