International Journal of Oral Implantology, 02/2024

Purpose: To provide an overview of the outcomes of the use of autogenous platelet concentrates in immediate implant placement. Materials and methods: Based on an a priori protocol, a systematic search was performed of the National Library of Medicine (MEDLINE via PubMed), Embase and Scopus databases. Randomised and non-randomised controlled clinical trials on immediate implant placement including at least one study arm with use of platelet-rich fibrin or platelet-rich plasma as a gap filler between immediately placed implants and the alveolar bone were included. A random-effects meta-analysis model was built to assess the primary outcomes of marginal bone loss and probing pocket depths between test (platelet concentrates) and control (no graft or other graft materials) groups. A risk of bias assessment was performed and the Grading of Recommendations Assessment, Development and Evaluation approach was used to assess the certainty of evidence. Results: A total of 20 trials (595 immediate implants placed in 454 individuals) were included in the meta-analytic model. Based on the data from studies with a minimum post–prosthetic loading period of 6 months after immediate implant placement, overall, the application of platelet concentrates was associated with significantly lower marginal bone loss and probing pocket depth compared to the control groups (mean difference −0.36 mm; P < 0.01 and mean difference −0.47 mm; P < 0.01, respectively). No additional benefit of application of platelet concentrates was detected regarding primary stability of immediate implants. Subgroup analysis revealed significantly lower marginal bone loss with xenogeneic bone alone compared to platelet concentrates alone as grafting material in immediate implant placement (mean difference 0.66 mm; P < 0.01). Evidence on soft tissue outcomes and aesthetic parameters was scarce. Conclusions: A low level of certainty based on the Grading of Recommendations Assessment, Development and Evaluation approach indicates superior outcomes in terms of marginal bone loss and probing pocket depth in immediate implant placement with the use of platelet concentrates versus no graft. Future research should be tailored towards a standardised protocol for preparation of platelet concentrates and inclusion of soft tissue and aesthetic outcomes as well. Keywords: dental implants, immediate implants, platelet concentrates, platelet-rich fibrin, platelet-rich plasma The authors report no conflicts of interest relating to this study.

Purpose: To examine the effects of buccal bone fenestration on maxillary anterior implants. Materials and methods: Patients who underwent implant placement in the maxillary anterior region between January 2017 and December 2021 and had received final restorations 1 to 6 years prior were screened for inclusion in the present study. Propensity score matching was used to match the two-group sample size and reduce the influence of potential confounding factors. Generalised linear mixed models were employed to evaluate the correlation between buccal bone fenestration and peri-implant marginal bone loss. Results: A total of 42 patients with 50 implants were included in the study, 16 of whom had buccal bone fenestration (group 1) and 26 of whom did not (group 2). No implant failures occurred, resulting in a cumulative implant survival rate of 100.0%. There was no statistically significant difference between the pink aesthetic scores for the two groups. The mean marginal bone loss was 0.44 ± 0.46 mm for group 1 and 0.33 ± 0.32 mm for group 2 (P > 0.05). Buccal bone fenestration was not the influencing factor of marginal bone loss (P > 0.05). Marginal bone loss was greater around implants used to replace canines than those inserted to replace central incisors (P < 0.05). Far less marginal bone loss occurred around immediately loaded implants than delayed implants with cover screws (P < 0.05). When there is sufficient keratinised mucosa around the implant, marginal bone loss will decrease significantly (P < 0.05). Conclusions: Within the limitations of this study, buccal bone fenestration defects around dental implants cannot influence peri-implant bone loss.Conflict-of-interest statement: The authors report no conflicts of interest relating to this study. Keywords: fenestration, implant, marginal bone loss, maxillary anterior region The authors report no conflicts of interest relating to this study.

Purpose: The reverse guided bone regeneration protocol is a digital workflow that has been introduced to reduce the complexity of guided bone regeneration and promote prosthetically guided bone reconstruction with a view to achieving optimal implant placement and prosthetic finalisation. The aim of the present study was to investigate the accuracy of this digital protocol. Materials and methods: Sixteen patients with partial edentulism in the maxilla or mandible and with vertical or horizontal bone defects were treated using the reverse guided bone regeneration protocol to achieve fixed implant rehabilitations. For each patient, a digital wax-up of the future rehabilitation was created and implant planning was carried out, then the necessary bone reconstruction was simulated virtually and the CAD/CAM titanium mesh was designed and used to perform guided bone regeneration. The computed tomography datasets from before and after guided bone regeneration were converted into 3D models and aligned digitally. The actual position of the mesh was compared to the virtual position to assess the accuracy of the digital project. Surgical and healing complications were also recorded. A descriptive analysis was conducted and a one-sample t test and Wilcoxon test were utilised to assess the statistical significance of the accuracy. The level of significance was set at 0.05. Results: A total of 16 patients with 16 treated sites were enrolled. Comparing the virtually planned mesh position with the actual position, an overall mean discrepancy between the two of 0.487 ± 0.218 mm was achieved. No statistically significant difference was observed when comparing this to a predefined minimum tolerance (P = 0.06). No surgical complications occurred, but two healing complications were recorded (12.5%). Conclusion: Within the limitations of the present study, the reverse guided bone regeneration digital protocol seems to be able to achieve good accuracy in reproducing the content of the virtual plan. Nevertheless, further clinical comparative studies are required to confirm these results. Keywords: accuracy, CAD/CAM, guided bone regeneration, preliminary results, titanium mesh The authors declare there are no conflicts of interest relating to this study.

Maxillary sinus grafting is a predictable regenerative technique to facilitate maxillary posterior implant placement when there is insufficient vertical bone height inferior to the maxillary sinuses to allow placement of implants of adequate dimensions. It enables an increase in vertical bone height, which makes implant placement easier. Maxillary sinus mucosal membrane perforation is one of the most common intraoperative complications during maxillary sinus grafting and may result in extrusion of graft material into the sinus. When this occurs, the mucociliary function of the maxillary sinus may expel the extruded graft material through its natural ostium, though graft particles may remain in the sinus or possibly occlude the natural ostium. After grafting, transient maxillary sinus mucosal oedema may occur. A postoperative CBCT scan may reveal varying degrees of sinus opacification, namely partial, subtotal or total. Although it is always possible to identify graft material, which may enter the sinus as a result of membrane perforation that might not even be visible to the implantologist during the surgical procedure, it is challenging to assess whether sinus opacification is due to mucosal thickening or mucus accumulation. The aim of the present case series was to offer a pragmatic approach to managing asymptomatic patients whose CBCT scans demonstrated partial, subtotal or total maxillary sinus opacification with bone graft particles that seemed to have been extruded into the sinus. Keywords: maxillary antrum, maxillary sinus elevation, maxillary sinus grafting, osteomeatal complex, osteomeatal unit, sinus membrane perforation, sinus mucosa, sinus opacification, transient swelling The authors declare no conflicts of interest relating to this study.

Purpose: Complex bone defects with a horizontal and vertical combined deficiency pose a clinical challenge in implant dentistry. This study reports the case of a young female patient who presented with a perforating bone defect in the aesthetic zone. Materials and methods: Based on prosthetically guided bone regeneration, virtual 3D bone augmentation was planned. A 3D printed customised titanium mesh and the autogenous bone ring technique were then utilised simultaneously to achieve a customised bone contour. After 6 months, the titanium mesh was removed and connective tissue grafting was performed. Finally, implants were placed and the provisional and definitive prostheses were delivered following a digital approach. Vertical and horizontal bone gain, new bone density, pseudo-periosteum type and marginal bone loss were measured. Planned bone volume, regenerated bone volume and regeneration rate were analysed. Results: Staged tooth shortening led to a coronal increase in keratinised mucosa. The customised titanium mesh and bone ring technique yielded 14.27 mm vertical bone gain and 12.9 mm horizontal bone gain in the perforating area. When the titanium mesh was removed, the reopening surgery showed a Type 1 pseudo-periosteum (none or < 1 mm), and CBCT scans revealed a new bone density of ~550 HU. With a planned bone volume of 1063.55 mm3, the regenerated bone volume was 969.29 mm3, indicating a regeneration rate of 91.14%. The 1-year follow-up after definitive restoration revealed no complications except for 0.55 to 0.60 mm marginal bone loss. Conclusion: Combined application of customised titanium mesh and an autogenous bone ring block shows promising potential to achieve prosthetically guided bone regeneration for complex bone defects in the aesthetic zone. Keywords: aesthetic zone, bone ring technique, complex bone defect, customised titanium mesh, guided bone regeneration The authors declare no potential conflict of interests with respect to this study. This work was supported by the National Natural Science Foundation of China (32071362), Senior Medical Talents Programme of Chongqing for Young and Middle-aged (2023GDRC001) and CQMU Programme for Youth Innovation in Future Medicine (W0077).