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Peri-implantitis: summary and consensus statements of group 3. The 6th EAO Consensus Conference 2021
(2021)
Objective: To evaluate the influence of implant and prosthetic components on peri-implant tissue health. A further aim was to evaluate peri-implant soft-tissue changes following surgical peri-implantitis treatment. Materials and methods: Group discussions based on two systematic reviews (SR) and one critical review (CR) addressed (i) the influence of implant material and surface characteristics on the incidence and progression of peri-implantitis, (ii) implant and restorative design elements and the associated risk for peri-implant diseases, and (iii) peri-implant soft-tissue level changes and patient-reported outcomes following peri-implantitis treatment. Consensus statements, clinical recommendations, and implications for future research were discussed within the group and approved during plenary sessions. Results: Data from preclinical in vivo studies demonstrated significantly greater radiographic bone loss and increased area of inflammatory infiltrate at modified compared to non-modified surface implants. Limited clinical data did not show differences between modified and non-modified implant surfaces in incidence or progression of peri-implantitis (SR). There is some evidence that restricted accessibility for oral hygiene and an emergence angle of >30 combined with a convex emergence profile of the abutment/prosthesis are associated with an increased risk for peri-implantitis (CR). Reconstructive therapy for peri-implantitis resulted in significantly less soft-tissue recession, when compared with access flap. Implantoplasty or the adjunctive use of a barrier membrane had no influence on the extent of peri-implant mucosal recession following peri-implantitis treatment (SR).
Rho GTPases are involved in homing and mobilization of hematopoietic stem and progenitor cells due to their impact on cytoskeleton remodeling. We have previously shown that inhibition of Rho, Rac and Cdc42 clearly impairs adhesion of normal and leukemic hematopoietic progenitor cells (HPC) to fibronectin and migration in a three-dimensional stromal cell model. Here, we identified the Ras GTPase-Activating Protein SH3 Domain-Binding Protein (G3BP) as a target gene of Rho GTPases and analysed its role in regulating HPC motility. Overexpression of G3BP significantly enhanced adhesion of murine 32D HPC to fibronectin and human umbilical vein endothelial cells, increased the proportion of adherent cells in a flow chamber assay and promoted cell migration in a transwell assay and a three-dimensional stromal cell model suggesting a strong impact on the cytoskeleton. Immunofluorescent staining of G3BP-overexpressing fibroblasts revealed a Rho-like phenotype characterized by formation of actin stress fibers in contrast to the Rac-like phenotype of control fibroblasts. This is the first report implicating a role for G3BP in Rho GTPase-mediated signalling towards adhesion and migration of HPC. Our results may be of clinical importance, since G3BP was found overexpressed in human cancers.
Radiographic outcomes following lateral alveolar ridge augmentation using autogenous tooth roots
(2018)
Background: To assess and compare the radiographic outcomes following lateral alveolar ridge augmentation using autogenous tooth roots (TR) and autogenous bone (AB) blocks.
Methods: In a total of 30 patients, lateral ridge augmentation was conducted in parallel groups using either (1) healthy autogenous tooth roots (e.g., retained wisdom or impacted teeth) (n = 15) or (2) cortical autogenous bone blocks harvested from the retromolar area. Cone-beam computed tomographic (CBCT) scans taken at 26 weeks of submerged healing were analyzed for the basal graft integration (i.e., contact between the graft and the host bone in %) (BI26) and the cross-sectional grafted area (mm2) (SA26).
Results: Both groups revealed a comparable clinical width of the alveolar ridge at baseline (CWb). Mean BI26 and SA26 values amounted to 69.26 ± 26.01% (median 72.44) and 22.07 ± 12.98 mm2 (median 18.83) in the TR group and 79.67 ± 15.66% (median 78.85) and 12.42 ± 10.11 mm2 (median 11.36) in the AB group, respectively. Between-group differences in mean SA26 values were statistically significant (p = 0.031). Linear regression analysis failed to reveal any significant correlations between BI26 and CWb/SA26 values in either group.
Conclusions: TR grafts may be associated with improved SA26 values following lateral alveolar ridge augmentation.
Trial registration: DRKS00009586. Registered 10 February 2016.
An oroantral fistula (OAF) is a pathological abnormal communication between the oral cavity and the maxillary sinus which may arise as a result of failure of primary healing of an OAF, dental infections, osteomyelitis, radiation therapy, trauma, or iatrogenic complications. With the presence of a fistula, the maxillary sinus is permanently open. Microbial flora passes from the oral cavity into the maxillary sinus, and the inflammation of the sinus occurs with all potential consequences. In literature, various techniques have been proposed for closure of OAFs. Due to the heterogeneity of the data and techniques found, we opted for a narrative review to highlight the variety of techniques discussed in the literature. Techniques of particular interest include the bone sandwich with resorbable guided tissue regeneration (GTR) membrane and platelet-rich fibrin (PRF) used alone as both a clot and a membrane. The great advantage of these techniques is that no donor site surgery is necessary, making the outcome valuable in terms of time savings, cost and, more importantly, less discomfort to the patient. Additionally, both bony and soft tissue closure is performed for OAF, in contrast to flaps, which are typically used for procedures in the sinus area. The reconstructed bony tissue regenerated from these techniques will also be appropriate for endosseous dental implantation.
Objectives: To evaluate peri-implant tissue dimensions following nonsurgical (NS) and surgical therapy (S) employing different decontamination protocols of advanced ligature-induced peri-implantitis in dogs.
Material & Methods: Peri-implantitis defects (n = 5 dogs, n = 30 implants) were randomly and equally allocated in a split-mouth design to NS or S treatment using either an Er:YAG laser (ERL), an ultrasonic device (VUS), or plastic curettes + local application of metronidazole gel (PCM), respectively. Horizontal bone thickness (hBT) and soft tissue thickness (hMT) were measured at different reference points: (v0) at the marginal portion of the peri-implant mucosa (PM); (v1) at 50% of the distance from PM to bone crest (BC); (v2) at the BC; (v3) at the most coronal extension of the bone-to-implant contact. Vertical peri-implant tissue height was calculated from PM to BC.
Results: All of the treatment groups showed a gradual hMT increase from v0 to the v2 reference point, followed by a reduction from v2 to the v3 region. The S-VUS subgroup tended to be associated with higher hMT values at the v0 region than the NS-VUS subgroup (0.44 mm versus 0.31 mm). PM-BC distance varied from 2.22 to 2.83 mm in the NS group, and from 2.07 to 2.38 in the S group.
Conclusion: Vertical and horizontal peri-implant tissue dimensions were similar in different treatment groups.
Objectives: To assess the short‐term clinical outcomes of lateral augmentation of deficient extraction sockets and two‐stage implant placement using autogenous tooth roots (TR).
Material and methods: A total of n = 13 patients (13 implants) were available for the analysis. At the time of tooth extraction, each subject had received lateral augmentation using the respective non‐retainable but non‐infected tooth root where the thickness of the buccal bone was <0.5 mm or where a buccal dehiscence‐type defect was present. Titanium implants were placed after a submerged healing period of 6 months and loaded after 20 ± 2 weeks (V8). Clinical parameters (e.g., bleeding on probing—BOP, probing pocket depth—PD, mucosal recession—MR, clinical attachment level—CAL) were recorded at V8 and after 26 ± 4 weeks (V9) of implant loading.
Results: At V9, all patients investigated revealed non‐significant changes in mean BOP (−19.23 ± 35.32%), PD (0.24 ± 0.49 mm), MR (0.0 ± 0.0 mm) and CAL (0.24 ± 0.49 mm) values, respectively. There was no significant correlation between the initial gain in ridge width and changes in BOP and PD values.
Conclusions: The surgical procedure was associated with stable peri‐implant tissues on the short‐term.
Background: To volumetrically assess the bone microstructure following vertical alveolar ridge augmentation using differently conditioned autogenous tooth roots (TR) and second‐stage implant placement.
Materials and methods: The upper premolars were bilaterally extracted in n = 4 beagle dogs and randomly assigned to either autoclavation (TR‐A) or no additional treatment (TR‐C). Subsequently, TR were used as block grafts for vertical alveolar ridge augmentation in both lower quadrants. At 12 weeks, titanium implants were inserted and left to heal 3 weeks. Microcomputed tomography was used to quantify bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp) at vestibular (v) and oral (o) aspects along the implant and in the augmented upper half of the implant, respectively.
Results: Median BV/TV [TR‐C: 51.33% (v) and 70.42% (o) vs TR‐A: 44.05% (v) and 64.46% (o)], Tb.th [TR‐C: 0.22 mm (v) and 0.27 mm (o) vs TR‐A: 0.23 mm (v) and 0.29 mm (o)] and Tb.Sp [TR‐C: 0.26 mm (v) and 0.13 mm (o) vs TR‐A: 0.29 μm (v) and 0.15 mm (o)] values were comparable in both groups.
Conclusion: Both TR‐C and TR‐A grafts were associated with a comparable bone microstructure within the grafted area.
Background: The present study aimed to assess the three‐dimensional changes following soft tissue augmentation using free gingival grafts (FGG) at implant sites over a 3‐month follow‐up period.
Methods: This study included 12 patients exhibiting deficient keratinized tissue (KT) width (i.e., <2 mm) at the vestibular aspect of 19 implants who underwent soft tissue augmentation using FGG at second stage surgery following implant placement. Twelve implants were considered for the statistical analysis (n = 12). The region of interest (ROI) was intraorally scanned before surgery (S0), immediately post‐surgery (S1), 30 (S2) and 90 (S3) days after augmentation. Digital scanned files were used for quantification of FGG surface area (SA) and converted to standard tessellation language (STL) format for superimposition and evaluation of thickness changes between the corresponding time points. FGG shrinkage (%) in terms of SA and thickness was calculated between the assessed time points.
Results: Mean FGG SA amounted to 91 (95% CI: 63 to 119), 76.2 (95% CI: 45 to 106), and 61.3 (95% CI: 41 to 81) mm2 at S1, S2, and S3, respectively. Mean FGG SA shrinkage rate was 16.3% (95% CI: 3 to 29) from S1 to S2 and 33% (95% CI: 19 to 46) from S1 to S3. Mean thickness gain from baseline (S0) to S1, S2, and S3 was 1.31 (95% CI: 1.2 to 1.4), 0.82 (95% CI: 0.5 to 1.12), and 0.37 (0.21 to 0.5) mm, respectively. FGG thickness shrinkage was of 38% (95% CI: 17.6 to 58) from S1 to S2 and 71.8% (95% CI: 60 to 84) from S1 to S3. Dimensional changes from S1 to S3 were statistically significant, P <0.017. Soft tissue healing was uneventful in all patients.
Conclusions: The present three‐dimensional assessment suggests that FGG undergo significant dimensional changes in SA and thickness over a 3‐month healing period.
Aim: To assess volumetric tissue changes at peri‐implantitis sites following combined surgical therapy of peri‐implantitis over a 6‐month follow‐up period.
Materials and Methods: Twenty patients (n = 28 implants) diagnosed with peri‐implantitis underwent access flap surgery, implantoplasty at supracrestally or bucally exposed implant surfaces and augmentation at intra‐bony components using a natural bone mineral and application of a native collagen membrane during clinical routine treatments. The peri‐implant region of interest (ROI) was intra‐orally scanned pre‐operatively (S0), and after 1 (S1) and 6 (S2) months following surgical therapy. Digital files were converted to standard tessellation language (STL) format for superimposition and assessment of peri‐implant volumetric variations between time points. The change in thickness was assessed at a standardized ROI, subdivided into three equidistant sections (i.e. marginal, medial and apical). Peri‐implant soft tissue contour area (STCA) (mm2) and its corresponding contraction rates (%) were also assessed.
Results: Peri‐implant tissues revealed a mean thickness change (loss) of −0.11 and −0.28 mm at 1 and 6 months. S0 to S1 volumetric variations pointed to a thickness change of −0.46, 0.08 and 0.4 mm at marginal, medial and apical regions, respectively. S0 to S2 analysis exhibited corresponding thickness changes of −0.61, −0.25 and −0.09 mm, respectively. The thickness differences between the areas were statistically significant at both time periods. The mean peri‐implant STCA totalled to 189.2, 175 and 158.9 mm2 at S0, S1 and S2, showing a significant STCA contraction rate of 7.9% from S0 to S1 and of 18.5% from S0 to S2. Linear regression analysis revealed a significant association between the pre‐operative width of keratinized mucosa (KM) and STCA contraction rate.
Conclusions: The peri‐implant mucosa undergoes considerable volumetric changes after combined surgical therapy. However, tissue contraction appears to be influenced by the width of KM.
Background: Recent advances in 3D printing technology have enabled the emergence of new educational and clinical tools for medical professionals. This study provides an exemplary description of the fabrication of 3D‐printed individualised patient models and assesses their educational value compared to cadaveric models in oral and maxillofacial surgery.
Methods: A single‐stage, controlled cohort study was conducted within the context of a curricular course. A patient's CT scan was segmented into a stereolithographic model and then printed using a fused filament 3D printer. These individualised patient models were implemented and compared against cadaveric models in a curricular oral surgery hands‐on course. Students evaluated both models using a validated questionnaire. Additionally, a cost analysis for both models was carried out. P‐values were calculated using the Mann‐Whitney U test.
Results: Thirty‐eight fourth‐year dental students participated in the study. Overall, significant differences between the two models were found in the student assessment. Whilst the cadaveric models achieved better results in the haptic feedback of the soft tissue, the 3D‐printed individualised patient models were regarded significantly more realistic with regard to the anatomical correctness, the degree of freedom of movement and the operative simulation. At 3.46 € (compared to 6.51 €), the 3D‐printed patient individualised models were exceptionally cost‐efficient.
Conclusions: 3D‐printed patient individualised models presented a realistic alternative to cadaveric models in the undergraduate training of operational skills in oral and maxillofacial surgery. Whilst the 3D‐printed individualised patient models received positive feedback from students, some aspects of the model leave room for improvement.