Titanium Allergy Caused by Dental Implants: A Systematic Literature Review and Case Report

(1) Background: Hypersensitivity reactions to metals may arise in predisposed patients chronically exposed to metallic materials, including dental implants made of titanium alloys. The purpose of this article was to systematically review titanium allergy manifestations in patients treated with dental implants and report a clinical case; (2) Methods: A systematic electronic search was performed for articles published in the English language until July 2021. The following eligibility criteria were adopted: (1) Population: individuals undergoing titanium and/or titanium alloy implant-supported rehabilitations; (2) Exposure: peri-implant soft tissue reactions attributable to implant insertion; (3) Outcome: evidence of titanium allergy, diagnostic methods, and forms of resolution; (3) Results: The included studies, in summary, presented evidence that titanium should not be considered an inert material, being able to trigger allergic reactions, and may be responsible for implant failure. A 55-year-old male patient received 3 implants in the posterior region of the left mandible and presented an epulis-like lesion developed from the peri-implant mucosa. The immunohistochemical analysis of the biopsy specimen confirmed the initial diagnosis of allergic reaction to titanium; (4) Conclusions: Although the evidence is weak, and titanium allergy has a low incidence, hypersensitivity reactions should not be underestimated. A rapid and conclusive diagnosis is mandatory to prevent further complications.

209 A Comparison of Soft Tissue Reactions Seen with Different Bone Anchored Hearing Aid Abutments: Smooth-Titanium Vs Hydroxyapatite-Coated

Aim Bone Anchored Hearing Aids allow hearing via stimulation of the cochlear through bone conduction. These devices are largely successful; however, soft tissue reactions often hinder their benefit. The type of abutment used could contribute to complications. We aimed to investigate whether using smooth-titanium abutments instead of hydroxyapatite-coated abutments reduced the rate of soft tissue reactions and need for revision surgery. Method A retrospective cohort analysis of all patients who received a Bone Anchored Hearing Aid during a 3-year period. An electronic database was screened for skin reactions and surgical revisions. A comparison was made between patients who received a hydroxyapatite-coated abutment and smooth-titanium abutments. The same surgical technique, linear incision skin preservation surgery, was used for inserting both abutments. Results Sixty-six patients received a Bone Anchored Hearing Aid. Forty-five patients received hydroxyapatite-coated abutments and twenty-one received smooth-titanium abutments, two patients had smooth-titanium inserted bilaterally. The groups were significantly similar with regards to age and gender. Significantly more patients who received hydroxyapatite-coated abutments recorded soft tissue reactions, 77.78% vs 23.81% (p < 0.0001). Significantly more patients who received hydroxyapatite-coated abutments required surgical revision, 40% vs 9.52% (p = 0.0197). 17.14% underwent skin revision and change of abutment. 5.7% had the abutments removed and were not immediately replaced. Conclusions When utilising skin preservation surgery for Bone Anchored Hearing Aid insertion smooth-titanium abutments have a favourable complication profile; with less soft tissue reactions and subsequent need for revision surgery, in comparison with hydroxyapatite-coated abutments. The reasons behind these differences warrant further investigations.

Radiographic evaluation of hip resurfacing: the role of x-rays in the diagnosis of a problematic resurfaced hip

Introduction: Hip resurfacing (HRA) requires a new standardised radiographic evaluation protocol. Evaluation of acetabular components is similar to total hip arthroplasty (THA) but femoral components require different criteria. This study evaluates the efficacy of a new femoral zonal system for radiographic HRA assessment in identifying clinical problems. Methods: A new proximal femoral zonal system divides implant-cement-bone interfaces at head and neck into 7 DeSmet zones. 611 in situ and 100 revised HRA were assessed for component positioning, borderline findings (reactive lines, cortical thickening, cancellous condensation) or sinister findings (lucent lines, bone resorption, osteolysis). Findings were correlated with gender, size, implant survival, clinical scores, metal ions, and adverse soft tissue reactions (ALTR). Results: Radiological changes were found in 265 hips (37.3%), 154 sinister (21.7%) and 111 borderline (15.6%). 84% of revisions had sinister findings versus 11.4% of in situ HRA ( p < 0.001). The mean number of abnormal acetabular and femoral zones was 3.3 in revised compared to 0.6 in situ HRA ( p < 0.001). Sinister findings were associated with female gender, lower clinical scores, smaller sizes or ASR design (all: p < 0.001). Metal ions were higher with sinister ( p < 0.001) and borderline ( p < 0.01) findings compared to normal radiographs. Pathological findings in ⩾4 zones had a sensitivity of 50% and specificity of 94.2% (AUC = 0.898) in detecting hips with ALTR (odds ratio = 49). Conclusion: In order to accurately evaluate progressive radiographic changes in HRA, specific zones have been established around the femoral component. There was a high correlation between radiographic findings and outcome measures. 84% of problematic hips and 90.4% of proven ALTR had sinister changes.

Aseptic Ligatures Induce Marginal Peri-Implant Bone Loss—An 8-Week Trial in Rabbits

The clinical value of ligature-induced experimental peri-implantitis studies has been questioned due to the artificial nature of the model. Despite repeated claims that ligatures of silk, cotton and other materials may not induce bone resorption by themselves; a recent review showed that the tissue reaction toward them has not been investigated. Hence, the current study aimed to explore the hard and soft tissue reactions toward commonly used ligature materials. A total of 60 dental implants were inserted into the femur (n = 20) and tibia (n = 40) of 10 rabbits. The femoral implants were ligated with sterile 3-0 braided silk in one leg and sterile cotton retraction chord in the other leg. The tibial implants were ligated with silk or left as non-ligated controls. All wounds were closed in layers. After a healing time of 8 weeks, femoral (silk versus cotton) and proximal tibial (silk versus non-ligated control) implants were investigated histologically. Distal tibial (silk versus non-ligated control) implants were investigated with real time polymerase chain reaction (qPCR). The distance from the implant-top to first bone contact point was longer for silk ligated implants compared to non-ligated controls (p = 0.007), but did not vary between cotton and silk. The ligatures triggered an immunological reaction with cell infiltrates in close contact with the ligature materials, adjacent soft tissue encapsulation and bone resorption. qPCR further demonstrated an upregulated immune response toward the silk ligatures compared to non-ligated controls. Silk and cotton ligatures provoke foreign body reactions of soft tissue encapsulation type and bone resorption around implants in the absence of plaque.

Clinical Results and Serum Metal Ion Concentrations following Ceramic-on-Metal Total Hip Arthroplasty at a Mean Follow-Up of 60 Months

Background. Increased metal ion levels following total hip arthroplasty (THA) with metal-on-metal bearings are a highly debated topic. Local soft tissue reactions with chronic pain and systemic side effects such as neuropathy are described. The aim of the current study was to determine the serum metal ion concentrations of Cobalt (Co) and Chrome (Cr) after THA with a ceramic-on-metal (CoM) bearing. Patients and Methods. Between 2008 and 2010, 20 patients underwent THA using a CoM bearing. Clinical function was evaluated by standardized scores systems (Harris Hip Score and WOMAC Score) and radiological examination included X-rays. Patient’s blood samples were obtained for metal ion analysis and correlation analysis was done between these results and implant position. Results. Overall, 13 patients with 14 CoM devices were available for the current series. The mean age at time of surgery was 61 years (range, 41 to 85). The postoperative follow-up ranged from 49 to 68 months (mean, 58). Metal ion determination showed mean concentrations of 3,1 µg/L (range, 0,3–15,2 µg/L) for Co and 1,6 µg/L (range, 0,1–5,5 µg/L) for Cr, respectively. A correlation between cup anteversion and Co and Cr concentrations was shown. Conclusion. The current series showed increments for Co and Cr following CoM THA. However, these levels are lower compared to metal ion concentrations in patients with metal-on-metal bearings and the international accepted threshold for revision of MoM devices. We recommend routine follow-up including at least one obligatory evaluation of serum metal ion concentrations and an MRI once to exclude local soft tissue reactions.