Effects of volume management on free flap perfusion and metabolism in a large animal model study.

Free flap failure represents a substantial clinical burden. The role of intraoperative volume management remains controversial, with valid studies lacking. Here, using a large animal model, we investigated the influence of volume management on free flap perfusion and metabolism. Autotransfer of a musculocutaneous gracilis flap was performed on 31 German domestic pigs, with arterial anastomosis and catheterization of the pedicle vein for sequential blood sampling. Flap reperfusion was followed by induction of a hemorrhagic shock with maintenance for 30 min and subsequent circulation stabilization with crystalloid solution, crystalloid solution and catecholamine, autotransfusion or colloidal solution. Flap perfusion and oxygenation were periodically assessed using hyperspectral imaging. Flap metabolism was assessed via periodic blood gas analyses. Hyperspectral imaging revealed no difference in either superficial or deep tissue oxygen saturation, tissue hemoglobin or tissue water content between the test groups at any time point. Blood gas analyses showed that lactate levels were significantly increased in the group that received crystalloid solution and catecholamine, after circulatory stabilization and up to 2 h after. We conclude that, in hemorrhagic shock, volume management impacts acid-base balance in free flaps. Crystalloid solutions with norepinephrine increase lactate levels, yet short-term effects on flap perfusion seem minimal, suggesting that vasopressors are not detrimental.

Esthetically driven immediate provisionalization in the anterior zone: 5-year results from a prospective study evaluating 3.0-mm-diameter tapered implants.

OBJECTIVES: Evaluate the 5-year safety and efficacy of a narrow-diameter (3.0 mm) implant that was immediately provisionalized with a single crown in the maxillary lateral incisor or mandibular central or lateral incisor area. MATERIALS AND METHODS: An open, prospective, single-cohort, multicenter study was conducted, in which narrow-diameter implants were placed in fresh, healed extraction, or congenitally missing sites. All patients were required to meet strict criteria for immediate loading. The primary endpoints were marginal bone levels (MBL) and MBL changes (MBLC) from implant placement to 5-year follow-up. Secondary endpoints included cumulative 5-year survival and success rates, soft tissue health, and esthetic parameters. RESULTS: A total of 91 implants were placed in 77 patients. The mean MBL remained stable from the 1-year (- 0.79 ± 0.73 mm, n = 75) to 5-year (- 0.74 ± 0.87 mm, n = 65) follow-up. A marginal bone gain of 0.11 ± 0.83 mm was observed from the 1-year to 5-year follow-up. The cumulative 5-year survival rate was 96.5%, and the cumulative 5-year success rate was 93%. The clinical parameters, including the modified plaque index, modified sulcus bleeding index, Jemt's papilla index, and pink esthetic score improved throughout the 5-year study. CONCLUSIONS: The study demonstrated that narrow-diameter implants represent a safe and predictable treatment option for subjects suitable for immediate loading and with limited bone volume or limited inter-dental space. CLINICAL RELEVANCE: Narrow-diameter implants with immediate provisionalization can be considered for use to restore missing or damaged teeth with predictable functional and esthetic outcomes. This trial was registered with ClinicalTrials.gov (NCT02184845).

Round and flat zygomatic implants: effectiveness after a 3­year follow­up non­interventional study.

PURPOSE: This non-interventional study investigates variations in the type and frequency of late complications linked to novel zygomatic implant designs, installed adhering to the Zygoma Anatomy-Guided Approach (ZAGA) concept, over an extended follow-up period of at least 3 years. METHODS: Consecutive patients presenting indications for treatment with ZIs were treated according to ZAGA recommendations. Implants were immediately loaded. The ORIS success criteria for prosthetic offset, stability, sinus changes and soft-tissue status were used to evaluate the outcome. RESULTS: Twenty patients were treated. Ten patients received two ZIs and regular implants; one received three ZIs plus regular implants, and nine received four ZIs. Fifty-nine ZIs were placed: thirty-six (61%) Straumann ZAGA-Flat implants and twenty-three (39%) Straumann ZAGA-Round implants. Four patients (20%) presented earlier sinus floor discontinuities. Fifteen patients (75%) had prior sinus opacities. Nineteen patients were followed for between 38 and 53 months (mean 46.5 months). One patient dropped out after 20 months. When comparing pre-surgical CBCT with post-surgical CBCT, 84.7% of the sites presented identical or less sinus opacity; nine locations (15%) showed decreased, and another nine increased (15%) post-surgical sinus opacity. Fifty-three ZIs (89.8%) maintained stable soft tissue. Six ZIs had recessions with no signs of infection. ZIs and prosthesis survival rate was 100%. CONCLUSIONS: The study highlights the effectiveness of ZAGA-based zygomatic implant rehabilitations using Round and Flat designs. Despite patient number constraints, minimal changes in the frequency of late complications from the 1-year follow-up were observed. 100% implant and prosthesis survival rate over a mean follow-up of 46.5 months is reported.

Towards optimized tissue regeneration: a new 3D printable bioink of alginate/cellulose hydrogel loaded with thrombocyte concentrate.

Introduction: Autologous platelet concentrate (APC) are pro-angiogenic and can promote wound healing and tissue repair, also in combination with other biomaterials. However, challenging defect situations remain demanding. 3D bioprinting of an APC based bioink encapsulated in a hydrogel could overcome this limitation with enhanced physio-mechanical interface, growth factor retention/secretion and defect-personalized shape to ultimately enhance regeneration. Methods: This study used extrusion-based bioprinting to create a novel bioink of alginate/cellulose hydrogel loaded with thrombocyte concentrate. Chemico-physical testing exhibited an amorphous structure characterized by high shape fidelity. Cytotoxicity assay and incubation of human osteogenic sarcoma cells (SaOs2) exposed excellent biocompatibility. enzyme-linked immunosorbent assay analysis confirmed pro-angiogenic growth factor release of the printed constructs, and co-incubation with HUVECS displayed proper cell viability and proliferation. Chorioallantoic membrane (CAM) assay explored the pro-angiogenic potential of the prints in vivo. Detailed proteome and secretome analysis revealed a substantial amount and homologous presence of pro-angiogenic proteins in the 3D construct. Results: This study demonstrated a 3D bioprinting approach to fabricate a novel bioink of alginate/cellulose hydrogel loaded with thrombocyte concentrate with high shape fidelity, biocompatibility, and substantial pro-angiogenic properties. Conclusion: This approach may be suitable for challenging physiological and anatomical defect situations when translated into clinical use.

Immediate versus delayed implant placement of novel fully tapered tissue-level implants - A retrospective multicenter clinical study.

OBJECTIVES: To compare the clinical and radiological outcomes of novel fully tapered tissue-level implants in immediate implant placement (type 1) versus late implant placement (type 4) for the first time. MATERIALS AND METHODS: For this clinical study, 318 fully tapered tissue-level implants in 65 patients were inserted immediately (n = 68 implants) or late (n = 250 implants) in two different centers. Implant survival and success rates and marginal bone levels were analyzed. RESULTS: After a mean follow-up of 12.0 ± 5 months, implant survival rates were 97.8% for all implants. No statistically significant difference in implant survival rates between type 1 and type 4 could be detected (98.5% vs 97.6%, HR 0.70, 95%-CI 0.084-5.81). Neither for implant length (HR 0.53, 95%-CI 0.055-5.08) nor for implant width (HR 0.27, CI 0.028-2.55), a significant influence on implant survival could be detected. Type of used biomaterial for filling the gap and immediate loading showed no effect on implant survival. Mean marginal bone loss was 0.02 ± 0.05 mm for type 1 and 0.04 ± 0.1 for type 4. CONCLUSIONS: Within the limitations of this retrospective study and the short follow-up, the results demonstrated comparable high survival and success rates and stable marginal bone levels for type 1 and type 4 placement of this novel tissue-level implant (no clinical trial registration as retrospective study design).

Evaluation of masticatory efficiency and OHRQoL in implant-retained overdenture with different numbers of implant in the edentulous mandible: a one-year follow-up prospective study.

PURPOSE: The aim of this article is to evaluate to the masticatory function performance and Oral Health-related Quality of Life (OHRQoL) in implant-retained overdenture compared with different implant number placements in the edentulous mandible. METHODS: From 2013 to 2015, each patients received 3 implants (iSy-Implant, Camlog, Wimsheim, Germany) in intraforaminal mandible (34, 41/31, 44). After operation, inserted implants were gradually loaded and incorporated into an overdenture with a self-aligning attachment system (Locator abutments) in 3 + 3 + 3 months. Five checked points were performed chewing cycle test with multicolored chewing gum and OHIP-G14 questionnaire and a sum score questionnaire as following: pre-operation, one implant load (41/31), two implants loaded (33,43), three implants loaded and 1-year follow up. RESULT: A total of 10 patients with 30 implants were placed, the survival rate of the implants was 100% within 1-year follow-up. Regarding the masticatory function analysis, for the higher number of chewing cycles, the higher mixing rate was observed. After 1 year, the inter-mixing rate without significant changes was found compared to the time after three implants were loaded with attachment system. The mean value of OHIP-G14 was 30.4 preoperatively, 21.1 after loading the first locator, 10.7 after loading two locator abutments, and 3.2 after loading all three locator abutments. After 1 year, OHIP-G14 was 2.6 without significantly changed. The mean of the sum score was 15.5 preoperatively, 27.8 after activation of the first locator, 39.4 after activation of two locators, 46.2 after activation of all three locators, and 47.3 after 1 year. An increase of 0.7 sum score units per time point was observed. No significance was detectable, analogous to OHIP-G14, compared to the time of activation of all three locator setups (p-value = 0.22). CONCLUSIONS: A significant improvement in masticatory function performance and OHRQoL was evaluated with the increasing number of implants with locator attachment in edentulous mandible. With the investigation of the OHIP-G14 and sum score, the results of patient report outcome might be associated with the increase in the number of implants.

The Perfect Timing-Immediate versus Delayed Microvascular Reconstruction of the Mandible.

In this retrospective study, the clinical and economic implications of microvascular reconstruction of the mandible were assessed, comparing immediate versus delayed surgical approaches. Utilizing data from two German university departments for oral and maxillofacial surgery, the study included patients who underwent mandibular reconstruction following continuity resection. The data assessed included demographic information, reconstruction details, medical history, dental rehabilitation status, and flap survival rates. In total, 177 cases (131 male and 46 females; mean age: 59 years) of bony free flap reconstruction (72 immediate and 105 delayed) were included. Most patients received adjuvant treatment (81% with radiotherapy and 51% combined radiochemotherapy), primarily for tumor resection. Flap survival was not significantly influenced by the timing of reconstruction, radiotherapy status, or the mean interval (14.5 months) between resection and reconstruction. However, immediate reconstruction had consumed significantly fewer resources. The rate of implant-supported masticatory rehabilitation was only 18% overall. This study suggests that immediate jaw reconstruction is economically advantageous without impacting flap survival rates. It emphasizes patient welfare as paramount over financial aspects in clinical decisions. Furthermore, this study highlights the need for improved pathways for masticatory rehabilitation, as evidenced by only 18% of patients with implant-supported dentures, to enhance quality of life and social integration.

Clinical insights into traumatic injury of the inferior alveolar and lingual nerves: a comprehensive approach from diagnosis to therapeutic interventions.

OBJECTIVES: This scoping review explores the risk and management of traumatic injuries to the inferior alveolar and lingual nerves during mandibular dental procedures. Emphasizing the significance of diagnostic tools, the review amalgamates existing knowledge to offer a comprehensive overview. MATERIALS AND METHODS: A literature search across PubMed, Embase, and Cochrane Library informed the analysis. RESULTS: Traumatic injuries often lead to hypo-/anesthesia and neuropathic pain, impacting individuals psychologically and socially. Diagnosis involves thorough anamnesis, clinical-neurological evaluations, and radiographic imaging. Severity varies, allowing for conservative or surgical interventions. Immediate action is recommended for reversible causes, while surgical therapies like decompression, readaptation, or reconstruction yield favorable outcomes. Conservative management, utilizing topical anesthesia, capsaicin, and systemic medications (tricyclic antidepressants, antipsychotics, and serotonin-norepinephrine-reuptake-inhibitors), proves effective for neuropathic pain. CONCLUSIONS: Traumatic nerve injuries, though common in dental surgery, often go unrecorded. Despite lacking a definitive diagnostic gold standard, a meticulous examination of the injury and subsequent impairments is crucial. CLINICAL RELEVANCE: Tailoring treatment to each case's characteristics is essential, recognizing the absence of a universal solution. This approach aims to optimize outcomes, restore functionality, and improve the quality of life for affected individuals.

Platelet-rich fibrin for rehydration and pre-vascularization of an acellular, collagen membrane of porcine origin.

OBJECTIVES: Pre-vascularization of the collagen membranes with autologous platelet concentrates is a standard procedure in oral and maxillofacial surgery. This study analyzed the possible interaction of an acellular collagen membrane of porcine origin (NM) with platelet-rich fibrin (PRF) regarding its rehydration protocol with differences in pH values and effect on angiogenesis. MATERIALS AND METHODS: NM was analyzed alone and combined with solid PRF by plotting or co-culturing with injectable PRF. Different media (venous blood, buffer solution with a fixed pH value of 7, saline solution, and injectable PRF) were used to analyze the influence on pH value during rehydration. Chorion allantois membrane assay (CAM) was applied to check pro-angiogenic effects after 24, 48, and 72 h, followed by immunohistochemical analysis. RESULTS: Rehydration in injectable PRF showed acidity over time (p < 0.05). A definite pro-angiogenic effect of NM alone was found regarding neo-vessel formation supported by the respective light microscopically analysis without significant differences to PRF alone (p > 0.005). This pro-angiogenic effect could not be exaggerated when NM was combined with liquid/solid PRF (each p > 0.005). CONCLUSIONS: Rehydration with liquid PRF of the collagen membrane results in acidity compared to a saline solution or patient's blood. The significant pro-angiogenic potential of the membrane alone resulted in enhanced neo-vessel formation that could not be optimized with the addition of PRF. CLINICAL RELEVANCE STATEMENT: Using injectable PRF for rehydration protocol of the collagen membrane leads to acidosis that can ultimately optimize wound healing. Differences in the physio-mechanical interplay of collagen matrices and autologous platelet concentrates must result in clinical algorithms if pre-vascularization can maximize outcomes.