Principles of Combined Surgical Therapy for the Management of Peri-Implantitis

The Effect of Implantoplasty on the Fatigue Behavior and Corrosion Resistance in Titanium Dental Implants

Implantoplasty is a technique increasingly used to remove the biofilm that causes peri-implantitis on dental implants. This technique of mechanization of the titanium surface makes it possible to eliminate bacterial colonies, but it can generate variations in the properties of the implant. These variations, especially those in fatigue resistance and electrochemical corrosion behavior, have not been studied much. In this work, fatigue tests were performed on 60 dental implants without implantoplasty, namely 30 in air and 30 in Hank's solution at 37 °C, and 60 with implatoplasty, namely 30 in air and 30 in Hank's solution at 37 °C, using triaxial tension-compression and torsion stresses simulating human chewing. Mechanical tests were performed with a Bionix servo-hydraulic testing machine and fracture surfaces were studied by scanning electron microcopyElectrochemical corrosion tests were performed on 20 dental implants to determine the corrosion potentials and corrosion intensity for control implants and implantoplasty implants. Studies of titanium ion release to the physiological medium were carried out for each type of dental implants by Inductively Coupled-Plasma Mass Spectrometry at different immersion times at 37 °C. The results show a loss of fatigue caused by the implantoplasty of 30%, observing that the nucleation points of the cracks are in the areas of high deformation in the areas of the implant neck where the mechanization produced in the treatment of the implantoplasty causes an exaltation of fatigue cracks. It has been observed that tests performed in Hank's solution reduce the fatigue life due to the incorporation of hydrogen in the titanium causing the formation of hydrides that embrittle the dental implant. Likewise, the implantoplasty causes a reduction of the corrosion resistance with some pitting on the machined surface. Ion release analyses are slightly higher in the implantoplasted samples but do not show statistically significant differences. It has been observed that the physiological environment reduces the fatigue life of the implants due to the penetration of hydrogen into the titanium forming titanium hydrides which embrittle the implant. These results should be taken into account by clinicians to determine the convenience of performing a treatment such as implantoplasty that reduces the mechanical behavior and increases the chemical degradation of the titanium dental implant.

Selecting biomaterials in the reconstructive therapy of peri-implantitis

Peri-implantitis is a pathogenic inflammatory condition characterized by progressive bone loss and clinical inflammation that may compromise the stability of dental implants. Therapeutic modalities have been advocated to arrest the disorder and to establish peri-implant health. Reconstructive therapy is indicated for bone defects exhibiting contained/angular components. This therapeutic modality is based upon the application of the biological and technical principles of periodontal regeneration. Nonetheless, the comparative efficacy of reconstructive therapy and nonreconstructive modalities remains unclear. Therefore, the aim of this narrative review is to address major clinical concerns regarding the efficacy, effectiveness, and feasibility of using biomaterials in peri-implantitis therapy. In particular, the use of bone grafting materials, barrier membranes, and biologics is comprehensively explored.

Characteristics, level of evidence, and impact of clinical studies on peri-implantitis: 2017 to 2021

BACKGROUND

The level of evidence (LOE) is an important tool in current evidence-based practice and clinical research. However, in clinical studies on peri-implantitis, the present status of the LOE and its association with research impact remains to be determined. The present study aimed to gather the characteristics and LOE of clinical studies on peri-implantitis conducted from 2017 to 2021 and assess the association of the LOE with social and scientific impact.

METHODS

The PubMed database was searched to retrieve clinical studies that evaluated peri-implantitis-related healthcare interventions and were published between 2017 and 2021. A 4-level modified Oxford 2011 LOE tool was used to determine the LOE of these studies. Citation count and Altmetric Attention Scores (AAS) were derived from the Web of Science and Altmetric Explorer, respectively. Multivariate generalized estimation equation (GEE) analysis was conducted to explore relationships between the LOE and citation count, and between the LOE and AAS; the publication year was considered the grouping factor for adjusting for potential clustering effects.

RESULTS

Two hundred and thirty-five studies were considered eligible. The percentages by level from Level-1 to Level-4 were 9.8%, 35.7%, 28.9%, and 25.5%. Multivariable GEE analyses revealed that studies with higher LOE ratings had significantly greater citation counts (p = 0.008). However, no significant association (p = 0.872) was observed between the LOE and AAS.

CONCLUSIONS

From 2017 to 2021, more than 40% of studies published on peri-implantitis each year had high-LOE ratings. High-LOE studies showed a tendency to have greater scientific impact.

Immunomodulatory IL-23 receptor antagonist peptide nanocoatings for implant soft tissue healing

OBJECTIVE

Peri-implantitis, caused by an inflammatory response to pathogens, is the leading cause of dental implant failure. Poor soft tissue healing surrounding implants - caused by inadequate surface properties - leads to infection, inflammation, and dysregulated keratinocyte and macrophage function. One activated inflammatory response, active around peri-implantitis compared to healthy sites, is the IL-23/IL-17A cytokine axis. Implant surfaces can be synthesized with peptide nanocoatings to present immunomodulatory motifs to target peri-implant keratinocytes to control macrophage polarization and regulate inflammatory axises toward enhancing soft tissue healing.

METHODS

We synthesized an IL-23 receptor (IL-23R) noncompetitive antagonist peptide nanocoating using silanization and evaluated keratinocyte secretome changes and macrophage polarization (M1-like "pro-inflammatory" vs. M2-like "pro-regenerative").

RESULTS

IL-23R antagonist peptide nanocoatings were successfully synthesized on titanium, to model dental implant surfaces, and compared to nonfunctional nanocoatings and non-coated titanium. IL-23R antagonist nanocoatings significantly decreased keratinocyte IL-23, and downstream IL-17A, expression compared to controls. This peptide noncompetitive antagonistic function was demonstrated under lipopolysaccharide stimulation. Large scale changes in keratinocyte secretome content, toward a pro-regenerative milieu, were observed from keratinocytes cultured on the IL-23R antagonist nanocoatings compared to controls. Conditioned medium collected from keratinocytes cultured on the IL-23R antagonist nanocoatings polarized macrophages toward a M2-like phenotype, based on increased CD163 and CD206 expression and reduced iNOS expression, compared to controls.

SIGNIFICANCE

Our results support development of IL-23R noncompetitive antagonist nanocoatings to reduce the pro-inflammatory IL-23/17A pathway and augment macrophage polarization toward a pro-regenerative phenotype. Immunomodulatory implant surface engineering may promote soft tissue healing and thereby reduce rates of peri-implantitis.

Volumetric tissue changes following combined surgical therapy of peri-implantitis: A 2-year follow-up analysis. A prospective case series

AIM

To assess volumetric tissue changes following combined surgical therapy of peri-implantitis over a follow-up period of 24 months.

MATERIALS AND METHODS

A total of 20 patients (n = 28 implants) were diagnosed with peri-implantitis and underwent access flap surgery, implantoplasty, and augmentative therapy at intrabony components (ie, combined therapy) using a natural bone mineral and a native collagen membrane. The peri-implant region of interest (ROI) was intraorally scanned pre-operatively (S0), and after 12 (S3) and 24 (S4) months. Digital files were superimposed for the assessment of volumetric changes between the referred time points. The change in thickness was assessed at a standardized ROI, segmented into two equidistant sections (ie, marginal and apical).

RESULTS

Peri-implant tissues exhibited a nonsignificant mean thickness loss of 0.16 (95% CI: -4 to 0.06) and 0.17 mm (95% CI: -0.05 to 0.4) at S3 and S4, respectively. S0-S3 dimensional thickness changes at marginal and apical areas were -0.24 (95% CI: -0.48 to 0.002) and -0.19 mm (95% CI: -0.36 to -0.2), respectively. Dimensional changes from S0 to S4 amounted to -0.22 mm (95% CI: -0.46 to 0.02) and -0.07 mm (95% CI: -0.09 to 0.2), respectively. The thickness changes at marginal and apical ROIs were significant from S0 to S3. Clinical parameters (ie, plaque index, bleeding on probing, and probing depth) significantly improved over the 24-month follow-up period. Linear regression analyses revealed no significant association between baseline bone loss (%), width of keratinized mucosa, and mucosal recession scores and thickness changes.

CONCLUSIONS

Peri-implant tissues revealed minor volumetric changes at 12 and 24 months after combined surgical therapy.