Effects of Abutment Removal and Reconnection on Inflammatory Cytokine Production Around Dental Implants

Retrospective Study of Functional and Esthetic Outcomes Using Narrow-Diameter Implants for Single Upper Central Incisor Replacements

Objectives: The upper central incisors play a central role in esthetics, symmetry, and function. The purpose of this study is to evaluate the use of narrow-diameter implants (NDIs) for replacing single missing upper central incisors, addressing the gap in research regarding specific tooth types and their esthetic outcomes. Methods: This retrospective study included adult patients with a single missing upper central incisor replaced by NDIs. Exclusion criteria included patients who lost adjacent teeth during follow-up and patients with non-loaded implants. The primary outcome was peri-implant bone stability, while secondary outcomes included implant survival, technical complications, patient satisfaction, and esthetic evaluation using the Pink Esthetic Score (PES) and the White Esthetic Score (WES). Descriptive statistical analysis was performed. Results: A total of 64 NDIs were placed in 64 patients (mean age 55 ± 15 years; 40 females, 24 males). Implant diameters were 3.3 and 3.5 mm, with lengths ranging from 6.5 to 11.0 mm. The mean follow-up period was 42 ± 19 months. Marginal bone loss was -0.7 ± 0.9 mm mesially and -0.5 ± 0.7 mm distally. No implant failures were recorded. Esthetic outcomes were satisfactory, with a mean PES of 7.0 ± 2.6 and a mean WES of 7.9 ± 2.0. Conclusions: NDIs demonstrated high survival rates, marginal bone stability, and acceptable esthetic outcomes in the replacement of single upper central incisors.

Effects of customized CAD/CAM abutments on cytokine levels in peri-implant crevicular fluid during early implant healing: a pilot study

OBJECTIVES

This study aimed to assess levels of biomarkers associated with inflammation and tissue destruction in peri-implant crevicular fluid (PICF) of implants provided with customized or standard healing abutments during early implant healing.

MATERIALS AND METHODS

Thirty implants were placed in 22 patients with partial posterior edentulism. Subsequently, test group implants (n=15) received one-piece titanium abutments that were fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM). Control group implants (n=15) were provided with standard abutments. PICF collection and standardized periapical radiographs were carried out at suture removal one week later, following crown delivery after 3 months and at 6 months. Expression of C-reactive protein (CRP), interferon-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12A, IL-17A, macrophage inflammatory protein (MIP)-1α, matrix metalloproteinase (MMP)-13, osteopontin, osteoactivin, Receptor Activator of NF-κB (RANK), and TGF-β were analyzed using a multiplex ELISA kit.

RESULTS

Both groups showed a significant decrease in protein expression of CRP, IL-1β, IL-6, IL-8, MIP-1α, osteopontin, osteoactivin, and TGF-β, while MMP-13 levels increased during the observation period. A rise in OPG and RANK levels was detected among customized abutments. Expression of CRP was higher, whereas IL-1β, IL-1α, and MIP-1α were decreased in control compared to test group implants after 6 months. Marginal bone loss did not depend on abutment modality.

CONCLUSIONS

Both abutment types showed distinctive temporal expression of inflammatory biomarkers during 6 months following implant placement.

TRIAL REGISTRATION

ISRCTN98477184, registration date 18/05/2022 CLINICAL RELEVANCE: Customized healing abutments exert similar effects on inflammation during early implant healing compared to standard healing abutments.

Upregulation of the JAK-STAT pathway promotes maturation of human embryonic stem cell-derived cardiomyocytes

The immature characteristics and metabolic phenotypes of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) restrict their applications for disease modeling, drug discovery, and cell-based therapy. Leveraging on the metabolic shifts from glycolysis to fatty acid oxidation as CMs mature, a human hexokinase1-GFP metabolic reporter cell line (H7 HK1-GFP) was generated to facilitate the isolation of fetal or more matured hPSC-CMs. RNA sequencing of fetal versus more matured CMs uncovered a potential role of interferon-signaling pathway in regulating CM maturation. Indeed, IFN-γ-treated CMs resulted in an upregulation of the JAK-STAT pathway, which was found to be associated with increased expression of CM maturation genes, shift from MYH6 to MYH7 expression, and improved sarcomeric structure. Functionally, IFN-γ-treated CMs exhibited a more matured electrophysiological profile, such as increased calcium dynamics and action potential upstroke velocity, demonstrated through calcium imaging and MEA. Expectedly, the functional improvements were nullified with a JAK-STAT inhibitor, ruxolitinib.

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RNA-seq revealed upregulation of IFN-signaling pathways during CM maturation

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IFN-γ-treated PSC-derived fetal CMs display increased MYH7:MYH6 ratio

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IFN-γ-treated PSC-derived fetal CMs exhibited improved electrophysiological profile

Laser microgrooved vs. machined healing abutment disconnection/reconnection: a comparative clinical, radiographical and biochemical study with split-mouth design

Background

Repeated removal and replacement of healing abutments result in frequent injuries to the soft tissues.

Purpose

The purpose of this study was to evaluate the effect of disconnection/reconnection of laser microgrooved vs. machined healing and prosthetic abutments on clinical periodontal parameters, marginal bone levels, and proinflammatory cytokine levels around dental implants.

Material and methods

Twenty-four patients each received 2 implants with one-stage protocol in a split-mouth design on the same jaw. In each patient, one healing and prosthetic abutments with a laser microgrooved surface (LMS group) and one healing and prosthetic abutments with machined surface (MS group) were used. Four months following implant placement (T0), the healing abutments were disconnnected and reconnected three times to carry out the impression procedures and metal framework try-in. Four weeks later (T1), definitive prosthetic abutments were installated with screw-retained crowns. Modified plaque index (mPI), modified gingival index (mGI) bleeding on probing (BOP), and probing depth (PD) were recorded at T0 and T1. At the same time points, samples for immunological analyses were taken from the sulcus around each implant. Peri-implant crevicular fluid (PICF) samples were analyzed for interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-α levels using the ELISA kit.

Results

At T0 and T1, mPI and mGI showed no statistical difference between the two groups, while higher PD and BoP values were noted for the MS group (P < 0.05). The mean PICF volume and mean concentrations of IL-1β, IL-6, and (TNF)-α in the LMS group were statistically less than those in the MS group (P < 0.05). In addition, comparison of IL-6 and IL-1β mean concentrations at T0 and T1 in the MS group showed a statistically significant increase (p < 0.05) over time, which was not noted for the LMS.

Conclusion

Disconnection/reconnection of healing and prosthetic abutments with a laser-microgrooved surface resulted in less inflammatory molecular response compared with conventional machined ones.

Trial registration

ClinicalTrials.govNCT04415801, registered 03/06/2020

A multicenter cohort study on the association of the one-abutment one-time concept with marginal bone loss around bone level implants

OBJECTIVES

To investigate the association of the one-abutment one-time concept with marginal bone loss (MBL) around bone-level implants in relation to other factors.

MATERIALS AND METHODS

Records from patients treated by four experienced implant surgeons between January 2016 and July 2019 were scrutinized. Subjects treated with two bone-level implant types with varying machined collar (subgroups: 0.5 and 0.8 mm) were considered, receiving a healing abutment (HA cohort) or a permanent abutment at the time of surgery (OT cohort). The primary outcome was MBL registered at 3 months and the longest follow-up. A clustered two-part regression model for semicontinuous data was used.

RESULTS

Data pertaining to 160 patients (92 females, mean age 54) and 344 implants (125 in HA cohort, 219 in OT cohort) were available for evaluation. Mean MBL amounted to 0.52 mm (SD 0.68) after a mean follow-up of 20 (SD 9.2) months, with 33.8% of the implants showing complete bone preservation and 5.0% demonstrating >2mm MBL. OT was not related to the presence of MBL using MBL as dependent binary variable (0: no MBL; 1: MBL irrespective of its magnitude). However, OT significantly reduced the magnitude of MBL with 0.300mm when compared to HA (p = .023) in the cases where MBL was detected. Subgroup (p = .212), smoking (p = .789), history of periodontitis (p = .839), type of edentulism (p = .054), implant surgeon (p = .079), patient compliance (p = .617), and follow-up (p = .443) failed to show a significant association with MBL in the regression model. Ninety-eight % of the implants survived.

CONCLUSION

Within the limitations of a cohort study, the one-abutment one-time concept was associated with a decrease in MBL at implant sites with bone loss. Therefore, the placement of a permanent abutment at the time of surgery seems relevant to limit marginal bone-level alterations.

The Effect of One-Abutment at One-Time on Marginal Bone Loss Around Implants Placed in Healed Bone: A Systematic Review of Human Studies

OBJECTIVES

The primary aim of the present article was to review the effect and the clinical significance of abutment dis- and reconnection on the peri-implant marginal bone levels.

MATERIALS AND METHODS

English articles published from 2009 to April 2019 were identified on the MEDLINE, Cochrane Library, and PubMed databases, according to the PRISMA guidelines. Comparative in vivo studies on humans were included.

RESULTS

A total of 4 studies with different levels of bias were included in this review. A significant heterogeneity of the reported data was observed, which limited the comparison of the findings. The only parameter that was homogenous throughout all 4 studies was the marginal bone level measurement.

CONCLUSION

Within the limitations of the present review, it can be suggested that minimizing the number of abutment dis- and reconnections would be beneficial to ensure minimal disruption to the peri-implant tissue and marginal bone level. However, the clinical significance of the marginal bone level changes is still inconclusive.

Dental implant surfaces treated with phosphoric acid can modulate cytokine production by blood MN cells

The study characterizes dental implant surfaces treated with phosphoric acid to assess the effects of acid treatment on blood cells and correlate them with cytokine levels. The implant surfaces examined were divided into untreated metal surface (US; n = 50), metal surface treated with phosphoric acid (ATS; n = 50) and cement surface (CS; n = 50) groups. The samples were characterized by scanning electron microscopy (SEM) and rheometry. The implants were incubated with human blood mononuclear cells for 24 h, with surface rinsing in the ATS treatment. Cell viability was determined by colorimetric methods and cytokines in the culture supernatant were quantified using flow cytometry. In the ATS group, the surface porosity and contact surface were increased and plaques were observed on the surface. The blood flow and viscosity curves were similar among the treatments, and the high cell viability rates indicate the biocompatibility of the materials used. An increase in the levels of IL-2, IL-4, IL-6, IL-10 and TNF-α was observed in the ATS and CS groups. There were positive correlations between IL-10 and IL-2 levels and between IL-10 and IL-4 levels in the culture supernatant of the ATS group. The results suggest that implant surface treatment with phosphoric acid activates the production of inflammatory cytokines. The increased cytokine levels can modulate the immune response, thereby improving biofunctional processes and promoting the success of dental implants.

One-time versus repeated abutment connection for platform-switched implant: A systematic review and meta-analysis

Objective

This review aims to compare peri-implant tissue changes in terms of clinical and radiographic aspects of implant restoration protocol using one-time abutment to repeated abutment connection in platform switched implant.

Method

A structured search strategy was applied to three electronic databases, namely, Pubmed, Embase and Web of Science. Eight eligible studies, including seven randomised controlled studies and one controlled clinical study, were identified in accordance with inclusion/exclusion criteria. Outcome measures included peri-implant bone changes (mm), peri-implant soft tissue changes (mm), probing depth (mm) and postsurgical complications.

Result

Six studies were pooled for meta-analysis on bone tissue, three for soft tissue, two for probing depth and four for postsurgical complications. A total of 197 implants were placed in one-time abutment group, whereas 214 implants were included in repeated abutment group. The implant systems included Global implants, Ankylos, JDEvolution (JdentalCare), Straumann Bone level and Conelog-Screwline. One-time abutment group showed significantly better outcomes than repeated abutment group, as measured in the standardised differences in mean values (fixed- and random-effect model): vertical bone change (0.41, 3.23) in 6 months, (1.51, 14.81) in 12 months and (2.47, 2.47) in 3 years and soft tissue change (0.21, 0.23). No significant difference was observed in terms of probing depth and complications.

Conclusion

Our meta-analysis revealed that implant restoration protocol using one-time abutment is superior to repeated abutment for platform switched implant because of less bone resorption and soft tissue shifts in former. However, future randomised clinical trials should be conducted to further confirm these findings because of the small samples and the limited quality of the original research.

Comparison of Proinflammatory Cytokine Levels in Gingival Crevicular Fluid around Dental Implants with Ceramic and Titanium Abutments

BACKGROUND

Considering the high success rate of osseoin-tegration, there is ever-increasing use of dental implants. The mechanisms and biologic response of peri-implant tissues are different depending on the biocompatibility of the implant material. The aim of this study was to compare the proinflammatory cytokine levels in the gingival crevicular fluid (GCF) around dental implants with ceramic and titanium abutments.

MATERIALS AND METHODS

All the patients with dental implants referring to two private offices of two prosthodontists from June to August 2016 were examined in relation to implant health, and eligible subjects, based on inclusion criteria, were included in this study with a slit-mouth design. In this context, on one side titanium implants and, on the other side, ceramic implants were used. Samples were collected from the peri-implant sulcus in each patient and sent to the immunology laboratory for determination of interleukin (IL)-6 and IL-1β proinflammatory cytokine levels using an enzyme-linked immunosorbent assay kit. Data were analyzed with Statistical Package for the Social Sciences version 16. Statistical significance was set at p < 0.05.

RESULTS

The results showed lower levels of IL-1β and IL-6 in the GCF around ceramic abutments compared with titanium implants. In addition, statistical comparison between IL-6 and IL-1β levels showed higher levels of IL-6 around titanium and ceramic abutments compared with IL-1β levels.

CONCLUSION

Based on the results of this study, the human body immune response to ceramic abutments is much better than that to titanium implants.

CLINICAL SIGNIFICANCE

Considering that proinflammatory cytokine levels in GCF around ceramic abutments are lower than titanium ones, ceramic abutments are preferred for clinical usage.