The German S3 guideline on titanium hypersensitivity in implant dentistry: consensus statements and recommendations

Understanding immune-mediated titanium allergy to in situ orthopaedic implants: a narrative review of the current literature

INTRODUCTION

Clinical recognition of potential immune-mediated allergic responses to implanted metal devices is increasing. For orthopaedic implants, while 'pure' compounds are used in specific circumstances, the majority of components are alloys - a combination of two or more distinct metals. Titanium is found commonly in many orthopaedic devices and is often championed as a 'hypoallergenic' option or inclusion. In the absence of a relevant previously published summary on the topic, this paper explores the current state-of-understanding of titanium allergy and proposes a patient management algorithm whereby such immune reactions are clinically-suggested.

METHODS

A structured, systematic literature review was performed following PRISMA search principles to provide a contemporary summary-of-understanding in this area and to highlight clinical and knowledge deficiencies.

RESULTS

Thirty-five topic-related articles were identified, the majority reflecting small case series' or proof-of-concept studies. The general standard of scientific evidence available was poor. Justification for arthroplasty utilization of titanium as a 'hypoallergenic' option is largely extrapolated from non-orthopaedic domains.

CONCLUSIONS

Both ionic and conjugated titanium particles released from implant surfaces have the potential to trigger innate immune responses and true allergy. There exists no simple, high-sensitivity, screening test for titanium allergy. Conventional skin-patch testing is unreliable due to poor dermal penetration. Given established lymphocyte and macrophage activation pathways for allergy responses, in vitro methods using both cell-types show diagnostic promise. Surgical biopsy analysis from host-implant interfaces remains the contemporary 'gold-standard', however this represents an invasive, costly and highly-specialized approach not readily available in most settings. Further research to establish reliable/accessible diagnostic methods are indicated.

Ceramic Implant Rehabilitation: Consensus Statements from Joint Congress for Ceramic Implantology: Consensus Statements on Ceramic Implant

The objectives of the study group focused on the following main topics related to the performance of 1- and 2-piece ceramic implants: defining bone-implant-contact percentages and its measurement methods, evaluating the pink esthetic score as an esthetic outcome parameter after immediate implantation, recognizing the different results of ceramic implant designs as redefined by the German Association of Oral Implantology, incorporating the patient report outcome measure to include satisfaction and improvement in oral health-related quality of life, and conducting preclinical studies to address existing gaps in ceramic implants. During the Joint Congress for Ceramic Implantology (2022), the study group evaluated 17 clinical trials published between 2015 and 2021. After extensive discussions and multiple closed sessions, consensus statements and recommendations were developed, incorporating all approved modifications. A 1-piece implant design features a coronal part that is fused to the implant body or interfaces with the postabutment restoration platform, undergoing transmucosal healing. Long-term evaluations of this implant design are supported by established favorable clinical evidence. Inaccuracies in the pink esthetic score and bone-implant-contact percentages were managed by establishing control groups for preclinical studies and randomizing clinical trials. The patient-reported outcome measures were adjusted to include an individual visual analog scale, collected from each clinical study, that quantified improved oral health and quality of life. Preclinical investigations should focus on examining the spread of ceramic debris and the impact of heat generation on tissue and cellular levels during drilling. Further technical advancements should prioritize wound management and developing safe drilling protocols.

Interaction of Telomere Length and Inflammatory Biomarkers Following Zirconia Implant Placement: A Case Series

Zirconia implants have gained popularity for their aesthetic appeal and biocompatibility, making them a preferred choice for anterior teeth replacement. This study explores the interaction between telomere length and inflammatory biomarkers in seven cases of zirconia implant placement to gain insights into postoperative cellular aging, inflammatory responses, and long-term outcomes. Zirconia implants offer advantages over titanium implants, as they do not corrode or release metal ions, leading to potential inflammation and implant failure. Monitoring immune and inflammatory biomarkers is essential to assess inflammation initiation, severity, and progression. C-reactive protein (CRP) and pro-inflammatory cytokines, like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), play crucial roles in host immune responses, while anti-inflammatory cytokines, including interleukin-10 (IL-10), regulate and dampen immune responses. Achieving a delicate balance between pro- and anti-inflammatory cytokines is vital for maintaining a healthy immune response and preventing chronic inflammatory conditions. Telomeres, protective structures present at chromosome ends, influence cellular aging and mitochondrial function. Shorter telomeres are associated with impaired mitochondrial function, increased oxidative stress, and cellular senescence, while longer telomeres are linked to reduced inflammation and improved immune function. Understanding these mechanisms is essential for addressing age-related conditions and promoting overall well-being. In this case series, we investigated the interaction between telomere length and inflammatory biomarkers in patients who received zirconia dental implants. The study aims to improve our understanding of postoperative cellular aging, inflammatory responses, and the biocompatibility of zirconia implants, potentially leading to improved treatment protocols and patient outcomes. This innovative assessment of telomere length and inflammatory biomarkers in the context of zirconia implants provides novel insights into the field of dental implantology. By exploring the effects of zirconia implants on cellular health and inflammation, this study contributes to advancements in implant technology and patient care.

Emission and Migration of Nanoscale Particles during Osseointegration and Disintegration of Dental Implants in the Clinic and Experiment and the Influence on Cytokine Production

The emission of nanoscale particles from the surfaces of dental implants leads to the cumulative effect of particle complexes in the bone bed and surrounding soft tissues. Aspects of particle migration with the possibility of their involvement in the development of pathological processes of systemic nature remain unexplored. The aim of this work was to study protein production during the interaction of immunocompetent cells with nanoscale metal particles obtained from the surfaces of dental implants in the supernatants. The ability to migrate nanoscale metal particles with possible involvement in the formation of pathological structures, in particular in the formation of gallstones, was also investigated. The following methods were used: microbiological studies, X-ray microtomography, X-ray fluorescence analysis, flow cytometry, electron microscopy, dynamic light scattering, and multiplex immunofluorescence analysis. For the first time, titanium nanoparticles in gallstones were identified by X-ray fluorescence analysis and electron microscopy with elemental mapping. The multiplex analysis method revealed that the physiological response of the immune system cells, in particular neutrophils, to nanosized metal particles significantly reduced TNF-a production both through direct interaction and through double lipopolysaccharide-induced signaling. For the first time, a significant decrease in TNF-a production was demonstrated when supernatants containing nanoscale metal particles were co-cultured with proinflammatory peritoneal exudate obtained from the peritoneum of the C57Bl/6J inbred mice line for one day.

Interaction of Ceramic Implant Materials with Immune System

The immuno-compatibility of implant materials is a key issue for both initial and long-term implant integration. Ceramic implants have several advantages that make them highly promising for long-term medical solutions. These beneficial characteristics include such things as the material availability, possibility to manufacture various shapes and surface structures, osteo-inductivity and osteo-conductivity, low level of corrosion and general biocompatibility. The immuno-compatibility of an implant essentially depends on the interaction with local resident immune cells and, first of all, macrophages. However, in the case of ceramics, these interactions are insufficiently understood and require intensive experimental examinations. Our review summarizes the state of the art in variants of ceramic implants: mechanical properties, different chemical modifications of the basic material, surface structures and modifications, implant shapes and porosity. We collected the available information about the interaction of ceramics with the immune system and highlighted the studies that reported ceramic-specific local or systemic effects on the immune system. We disclosed the gaps in knowledge and outlined the perspectives for the identification to ceramic-specific interactions with the immune system using advanced quantitative technologies. We discussed the approaches for ceramic implant modification and pointed out the need for data integration using mathematic modelling of the multiple ceramic implant characteristics and their contribution for long-term implant bio- and immuno-compatibility.