Objectives: To evaluate the long-term clinical outcomes of quad zygomatic implants (ZIs) as a rescue therapy for patients with failed full-arch implant rehabilitation in the maxilla due to advanced peri-implantitis.
Material and methods: This was a retrospective cohort study of all patients treated with the Quad Zygoma Protocol. Primary outcomes included the ZI survival and success rates, and secondary outcomes, the prosthetic success rate and complications.
Results: The study population included 28 consecutive patients who received 112 ZIs between 2006 and 2024, with a mean follow-up of 8.2 ± 4.1 years. In 23 patients, a total of 113 failed conventional implants were removed, and 48 ZIs were immediately placed into the explantation sites. The ZI survival rate was 98.2%, with two ZIs requiring removal due to late complications. The implant success rate was 93.5%, and prosthetic success was achieved in 96.4% of cases. Sinusitis was diagnosed in 8 patients (28.5%) at a mean of 5.92 years postoperatively; all cases were successfully managed medically without implant loss. Soft tissue recession occurred in 9.8% of cases, while oroantral fistula and facial fistula were each observed in 0.9% of implants.
Conclusions: The Quad Zygoma Protocol may represent a reliable and predictable option for the rescue of failed maxillary full-arch implant rehabilitations. Despite a relatively high prevalence of sinusitis, favorable long-term clinical outcomes were achieved with appropriate management.
Objective: This study follows a 2-year evaluation to verify marginal bone remodeling (MBR) trends associated with different abutment designs.
Methods: A balanced, randomised, double-blind clinical trial with two parallel experimental arms. 68 implants were placed in 9 men and 12 women, 48.5% using the straight abutment and 51.5% the concave abutment. The primary variable was peri-implant tissue stability, measured by marginal bone loss (MBL) or gain (MBG) through digital radiology. Mixed linear regression models and Additive Generalized Additive Models were constructed to estimate MBR, simultaneously considering the variables abutment height, group, and time.
Results: At 24 months, linear mixed-effects regression models revealed that the concave abutment group exhibited significantly less MBL than the straight abutment group across mesial, distal, and average measurements (p = 0.006-0.026). Significant interactions between abutment type and time at 8 weeks and 6 months suggest early and sustained benefits of the concave design. At 24 months, this effect remained significant except in the mesial model (p = 0.072). Abutment height was positively associated with MBL, particularly in the straight group; however, in the concave group, greater height mitigated bone loss (p < 0.01).
Conclusion: Concave abutments demonstrated a potential advantage in reducing early marginal bone loss and promoting mid-term bone stability compared to straight abutments. Their design may enhance soft tissue adaptation, contributing to improved peri-implant bone preservation. While increased abutment height showed a protective effect in the concave group, these findings require confirmation. Further long-term studies are warranted to validate these results and clarify their clinical relevance.
Peri-implantitis, a biofilm-associated inflammatory disease, significantly threatens dental implant longevity. Current treatments face limitations due to biofilm robustness. This study evaluates the efficacy of antimicrobial-releasing titanium-silica (Ti/SiO2) composite implant systems against multispecies oral biofilms, aiming to advance innovative localized and targeted peri-implantitis prevention and management strategies.
Ti/SiO2 inserts were engineered with macroporous Ti6Al4V discs produced by additive manufacturing (AM) and a sol–gel-derived mesoporous SiO2 barrier for controlled antimicrobial release across the discs. Chlorhexidine (CHX), as the gold standard antimicrobial agent in dental practice, was tested for its release efficacy using either a laboratory-prepared chlorhexidine diacetate solution (CHX-DA) or the commercial formulation Corsodyl. Phosphate-buffered saline (PBS) and Brain Heart Infusion-2 (BHI-2) medium served as control solutions. After establishing the CHX-DA release profile, multispecies biofilms were grown on the inserts. The antimicrobial efficacy of the release systems was assessed via viability-qPCR, scanning electron microscopy (SEM), and metabolic acid profiling. All experiments were conducted four times.
A mean pore diameter of 5.6 nm was observed for the discs, resulting in a steady drug release rate (≈0.00077 mmol/L CHX-DA/day). The antimicrobial-fed inserts showed less biofilm formation, with ≥ 2 log10 reductions in viable bacteria compared to controls. CHX-DA and Corsodyl showed effective suppression of pathogenic bacteria and reductions in metabolic acid production. SEM analysis revealed morphological changes in bacterial cells on treated surfaces.
Antimicrobial-releasing Ti/SiO2 implant discs demonstrated sustained efficacy in biofilm prevention and treatment, indicating their feasibility as a future strategy for peri-implantitis management.
This study investigated the effects of controlled in vivo repetitive mechanical loading on peri-implant tissue quantity and quality in a bisphosphonate (BP)-treated osteoporosis-like rat model.
At 3 months post-ovariectomy, Wistar rats were randomly assigned to receive either alendronate (ALN) or saline. Bilateral maxillary first molars were extracted at 9 weeks old, and Grade IV titanium implants were placed in healed alveolar ridges 4 weeks after starting treatment. Four weeks postimplantation, sites were randomly assigned to test (Load) or control (Non-load) groups. The Load group received controlled mechanical loading (10 N, 3 Hz, 1800 cycles, 2 days/week) via implants for 2 weeks. Peri-implant bone quantity and quality parameters were assessed, including micro-computed tomography (microCT)-derived morphometry, bone-related cell distribution, collagen composition and alignment, and sclerostin expression.
BRONJ stage 0-like lesions, characterized by necrotic bone with epithelium coverage, were observed in all ALN-treated maxillae. Despite comparable epithelial and microCT morphometry (p > 0.05), the Load group demonstrated significantly improved bone quality around implants, with reduced necrotic bone, higher osteocyte density, fewer osteoclasts and TRAP-positive mononuclear cells at the crestal site (p < 0.05), and greater deposition of well-aligned type I collagen (p < 0.05). Conversely, the Non-load group exhibited substantially larger necrotic areas, increased empty lacunae, reduced osteocyte density, increased sclerostin expression, and more disorganized type III collagen (p < 0.05).
This study is the first to demonstrate that implant loading alleviates BRONJ stage 0-like lesions by enhancing peri-implant bone quality. Mechanical loading promotes peri-implant bone health through cellular adaptation and extracellular matrix remodeling, even under BP-treated osteoporotic-like conditions.
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