Search Results (127)

Background: The role of collagen membrane fixation during guided bone regeneration (GBR) remains debatable, particularly in post-extraction sockets with buccal defects and concomitant immediate implant placement. This study evaluated whether or not fixation with titanium pins improved regenerative outcomes. Methods: Six adult Beagle dogs received bilateral extractions of the fourth mandibular premolars. An implant was immediately placed in both the distal alveoli, and standardized buccal bone defects (5 mm height, 3–2 mm width) were prepared. All defects were filled with a slowly resorbing equine xenograft and covered by a resorbable pericardium membrane. At the test sites, the membrane was apically fixed with pins, while no fixation was applied to the control sites. After 3 months of healing, histomorphometric analyses were performed. Results: The vertical bone gain of the buccal crest was 3.2 mm in the test sites (pin group) and 2.9 mm in the control sites (no-pin) (p > 0.754). No significant difference was found in terms of bone-to-implant contact (BIC). However, residual graft particles were located significantly more coronally in the pin group compared to the no-pin group (p = 0.021). Morphometric analyses revealed similar new bone formation within the groups, but with higher amounts of residual xenograft and soft tissue in the pin group. Conclusions: Membrane fixation did not significantly enhance vertical bone gain, and although the slightly higher regeneration in the pin group (3.2 mm vs. 2.9 mm) may hold clinical relevance in esthetically sensitive areas and osseointegration, it appeared to limit apical migration of the grafting material. Full article

Objective: To assess the bone histological changes and histomorphometric parameters when using different implant site preparation methods. Methods: A systematic search was conducted in March 2025 across the PubMed, Scopus, and Web of Science (WoS) databases following the PRISMA guidelines. An initial search of the databases yielded 338 potentially relevant articles. Ultimately, a total of 29 articles were included in the qualitative synthesis in this review. The considerable heterogeneity among the included studies precluded a meta-analysis. Results: This systematic review showed that, among all the assessed implant site preparation methods, which were drilling, laser, piezoelectric surgery, osteotomy and osteodensification, the classical drilling method was more likely to cause adverse changes at the drill site, such as microcracks, uneven bone margins, osteocyte damage and thermal injury. In contrast, alternative methods resulted in fewer microcracks, minimal inflammation, a reduced risk of thermal tissue damage and denser, more regular bone formation. When using these methods, the %BIC parameter was higher than when using the drilling method. Conclusions: Using alternative techniques to prepare the implant bed creates favourable conditions for proper healing and osseointegration by eliminating defects resulting from the drilling method. However, it should be noted that satisfactory results can be achieved using the classical method if the correct parameters of the drill rotation, cooling and load are employed. Further studies based on a uniform methodology are necessary to determine the most efficient and safest parameters for each method. Full article

Background/Objectives: Guided bone regeneration (GBR) is a regenerative technique used to treat maxillary osseous defects to enable implant placement for prosthetic rehabilitation. It is generally performed with the use of barrier membranes and bone substitute materials of human or animal origin. Here, we report the clinical and histological outcomes of a horizontal GBR, treated using only synthetic biomaterials. Methods: A graft of nanocrystalline hydroxyapatite (NH) embedded in a silica gel matrix was used to fill a horizontal bone defect. The graft was covered with a titanium-reinforced dense polytetrafluoroethylene (TR-dPTFE) membrane, and primary closure was completed and maintained for 10 months. Then, the site was re-opened for membrane removal and implant insertion. During implant bed preparation, a bone biopsy was obtained for histological evaluation. A metal–ceramic crown was fitted, and the 5-year follow-up after prosthetic loading showed clinical and radiographically healthy tissues. Results: Histological examination revealed good integration of the biomaterial into the surrounding tissues, which were composed of lamellar bone trabeculae and connective tissue. New bone formation occurred not only around the NH granules but even inside the porous amorphous particles. Conclusions: The combination of NH and the TR-dPTFE membrane produced good clinical and histological results, which remained stable for 5 years. Full article

The aim of this in vitro study was to evaluate the differences in heat generation across the drilling techniques, depths, and irrigation conditions of static computer-assisted implant surgery (S-CAIS) and conventional implant preparation (CIP) using a standardized bone model for comparative investigation. A total of 240 automated intermittent experimental procedures of 10 and 12 mm drilling depths were performed during S-CAIS and CIP using stainless steel twist drills of three drill diameters (2.2, 2.8, and 3.5 mm) and two irrigation modes (without/external cooling) at room temperature. Temperature changes were recorded in real time using multiple temperature sensors in two distances to the osteotomy site. For comparison, a linear mixed model was fitted. The level of statistical significance was set at α = 0.05. Comparing the two surgical techniques, significant temperature differences could be observed using 3.5 mm drills: CIP yielded statistically higher temperatures during 10 and 12 mm drilling without irrigation (p = 0.0115 and p = 0.0253, respectively), while statistically higher temperatures were observed with S-CAIS and external irrigation at a 12 mm drilling depth (p = 0.0101). This standardized in vitro investigation demonstrated the impact of surgical technique, drilling depth, and irrigation mode on heat generation, indicating differences especially in drills of larger diameter. Full article

Hierarchical porous hydrogels possess advantageous characteristics that facilitate cell adhesion, promote tissue growth, and enhance angiogenesis and osteogenesis. In this study, porous composite hydrogels were successfully prepared by a two-step gelation method with sodium alginate (SA), gelatin (GEL), and calcium hydrogen phosphate (DCP) as the main components. The fabricated porous hydrogels initially featured small pores (approximately 60 μm), and gradually evolved to large pores (exceeding 250 μm) during the gradual degradation in the cellular microenvironment. In vitro cell culture experiments indicated that these hydrogels could enhance the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells due to the hierarchical porous structure and the incorporation of DCP. Subcutaneous implantation and cranial defect repair experiments in Sprague−Dawley rats further confirmed that the small initial pore size of hydrogel scaffolds can provide more sites for cell adhesion. Additionally, the gradual degradation to form large pores was conducive to cell/tissue growth and blood vessel formation, ultimately being beneficial for vascularized bone regeneration. In summary, this study proposes an innovative strategy for developing porous hydrogels with gradual degradation for functional bone regeneration. Full article

Background: Cortical and marrow bone layer have different histomorphometric features. The traditional implant insertion technique provides for fixture stabilization through the cortical area. However, this approach has been found to result in an overstress of this bone layer, which may lead to resorption. Therefore, the aim of this study was to evaluate bone healing by applying two different implant site preparation protocols across various bone densities. Materials and Methods: One implant was placed in each femur and tibia of the rabbits (four implants per animal), using two distinct site preparation methods: drilling alone or drilling followed by osteotomes (funnel technique). Three regions around the implant were evaluated: cervical, marrow, and apical. The study included 12 rabbits, divided into two groups of 6 animals each, which were euthanized at 3 and 6 weeks, respectively (n = 6 per group). Results: In the cervical region of both femur and tibia, no marginal bone resorption could be detected. Similar BIC% (bone-to-implant contact percentages) were observed for funnel and drill sites after 3 weeks and 6 weeks of healing. Differences, though not statistically significant, ranged between 2.8% and 4.7%. However, higher BIC% values were observed in the femora compared to the tibia in both periods. Conclusions: No marginal bone loss was observed in both techniques. No statistically significant differences in bone resorption or bone-to-implant contact around the implant collar were observed when comparing two implant site preparation protocols across various bone densities. The use of osteotome did not influence the healing in the marrow region. Full article

This study assessed the shear bond strength (SBS) and failure modes of lithium disilicate ceramic veneering material to different high-performance polymers. Thirty-six square specimens measuring 7 × 7 × 2 ± 0.05 mm were prepared from pure polyetheretherketone (PEEK), Bio-high performance PEEK (BioHPP) and Trilor discs. Polymer specimens were air-borne abraded utilizing aluminum oxide particles, cleaned, and a bonding agent was applied (visio. link). The veneering LDC material (3 × 2 mm) was milled, hydrofluoric acid etched (9.5%) and primed (Clearfil ceramic). The LDC was bonded to the polymer specimens using dual-cured resin cement (Panavia V5) and light polymerized. The bonded specimens were subjected to 5000 cycles of physiological aging by thermocycling, and the SBS test was performed in a universal testing machine at 0.5 mm/min cross-head speed. The debonded specimens were analyzed to determine the primary bond failure sites (adhesive, mixed or cohesive). Data analysis was performed using one-way ANOVA and a post hoc Tukey test (α ≤ 0.05). The BioHPP material demonstrated the highest SBS values (23.94 ± 1.43 MPa), and the Trilor group recorded the lowest SBS values (17.09 ± 1.07 MPa). The PEEK group showed a mean SBS of 21.21 ± 1.51 MPa. The SBS comparison showed significant variations across all material groups (p < 0.001). Regarding failure modes, adhesive failure was observed in 40% of BioHPP and PEEK specimens and 90% of Trilor specimens. The cohesive failure occurred in 50% of PEEK and 30% of BioHPP specimens, while the Trilor specimens showed no cohesive failure. Mixed failures were reported in 30% of BioHPP and 10% of PEEK and Trilor specimens. The BioHPP material demonstrated high SBS followed by PEEK and Trilor. The SBS between the tested materials was statistically significant. However, the SBS of the tested implant framework materials was above the limit stipulated by the ISO 10477 standard (5 MPa) and the clinically acceptable range of 10–12 MPa. Full article

A key principle of guided bone regeneration (GBR) is the use of a barrier membrane to prevent cells from non-osteogenic tissues from interfering with bone regeneration in patients with hard tissue deficiencies. The aim of the study was to investigate whether the osteoinductive properties of bone-conditioned medium (BCM) obtained from cortical bone chips harvested at the surgical site can be transferred to a native bilayer collagen membrane (nbCM). BCM extracted within 20 or 40 min, which corresponds to a typical implant surgical procedure, and BCM extracted within 24 h, which corresponds to BCM released from the autologous bone chips in situ, contained significant and comparable amounts of TGF-β1, IGF-1, FGF-2, VEGF-A, and IL-11. Significant (p < 0.001) quantities of BMP-2 were only detected in the 24-h BCM preparation. The bioactive substances contained in the BCM were adsorbed to the nbCMs with almost 100% efficiency. A fast but sequential release of all investigated proteins occurred within 6–72 h, reflecting their stepwise involvement in the natural regeneration process. BCM-coated nbCM significantly (p < 0.05) increased the migratory, adhesive, and proliferative capacity of primary human bone-derived cells (hBC), primary human periodontal ligament cells (hPDLC), and an osteosarcoma-derived osteoblastic cell line (MG-63) compared to cells cultured on BCM-free nbCM. The high proliferative rates of MG-63 cells cultured on BCM-free nbCM were not further potentiated by BCM, indicating that BCM-coated nbCM has no detrimental effects on cancer cell growth. BCM-coated nbCM caused significant (p < 0.05) induction of early osteogenic marker gene expression and alkaline phosphatase activity, suggesting an important role of BCM-functionalized nbCM in the initiation of osteogenesis. The 24-h BCM loaded on the nbCM was the only BCM preparation that caused significant induction of late osteogenic marker gene expression. Altogether, our data define the pre-activation of collagen membranes with short-term-extracted BCM as a potential superior modality for treating hard tissue deficiencies via GBR. Full article

Objective: The objective of this study was to evaluate autologous platelet-rich fibrin (PRF) membrane weights and measurements after production by different centrifuges. Moreover, the values obtained with blood cellular components were correlated. Methods: Twelve systemically healthy participants underwent dental implant surgery associated with PRF membranes as the graft biomaterial at the implant site. Prior to the surgical procedure, the chosen participants underwent blood count and coagulogram tests and presented on the surgical day. Nine tubes containing 10 mL of venous blood were collected from each individual. The tubes were randomly distributed and positioned in three different centrifuges: (C1) the Intra-lock L-PRF Process, (C2) the Kasvi Digital, and (C3) the PRF Montserrat. PRF membrane processing was carried out as described by each manufacturer. After the processing steps, the prepared wet PRFs (initial) were placed in the container (box) designated by the manufacturer for the obtention of PRF membranes. The weights and measurements of the “wet” PRFs (initial) and membranes (final) were obtained using a precision scale and digital caliper in an aseptic environment. The data were compared, and the statistical differences were analyzed using the Friedman test and the Dunn post hoc test; Pearson correlation tests were performed between macroscopic data and data from serum tests; statistical significance was set at 5% (p < 0.05). Results: 108 blood collection tubes were collected. The average harvest time for each tube individually was 21.5 ± 9.9 s. The average time for blood collection (nine tubes) from each of the 12 individuals was 193.1 ± 72.4 s (p = 0.728). The average values were very similar between the centrifuges, both for the measurements and weights of the “plugs” as well as for the linear measurements (p > 0.05). Regarding the wet weights and the linear averages of the PRF membranes, it was observed that the wet PRF weights varied from 0.22 to 0.25 mg and the linear measurements from 24.1 to 26.7 mm, with no statistical differences between centrifuges (p > 0.05). The data presented by centrifuges C1 and C2 were more homogeneous, delivering a value of less than 25% variability compared to the C3 centrifuge, which achieved values greater than 33%. Conclusions: The proposed macroscopic dimensional evaluation found no differences between the autologous platelet concentrates obtained by different centrifuges, and no correlation was found between these PRFs and the patients’ blood counts. Full article

Background: The aim of this retrospective study was to compare the histomorphometry of post-extractive sites previously grafted with deproteinized bovine bone, with or without the association of a calcium sulphate preparation. Methods: The retrospective evaluation comprehended patients previously selected and treated for the extraction of one or more mono-radicular teeth, followed by an implant-prosthetic rehabilitation. Post-extractive sites had been randomly assigned to test or control group, respectively, if deproteinized bovine bone was used in association with a calcium sulphate preparation or alone. In both cases, a collagen membrane was employed to cover the grafted area. After four months, a biopsy of regenerated bone was taken from all grafted sites and then processed for histomorphometric analysis. Results: Of 24 samples analyzed 4 months after extraction, vital bone was present in 62.5% of cases for the test group and in 31.25% for the control group. Acellular bone was respectively found in 5% of cases for the test group and in 32.91% for the control group. Both these differences were statistically significant (p < 0.05) between groups. Conclusions: Calcium sulphate in association with deproteinized bovine bone seems to promote proper vital bone formation, with less acellular bone compared to deproteinized bovine bone used alone. Socket preservation procedures with the use of specific osteoconductive materials improve the maintenance of width and height of remaining bone. Findings of the present study offer clinicians a predictable protocol for preserving vital bone in early healing of post-extraction sites, slowing down the resorption process at the same time. Full article

Drilling for implant site preparation generates heat, which can cause bone necrosis if temperatures exceed 47 °C for over a minute. Factors influencing heat include drill size, speed, pressure, irrigation, and tool wear. Frequent drill replacement is essential, as wear from repeated use and sterilization affects performance. This study compared three pilot drills with similar designs from different manufacturers, testing each on pig ribs for 15 perforations after 15 sterilization cycles. Researchers measured temperature increase, drilling time, and surface wear. Results showed that drill no. 1 generated more heat than drills no. 2 and no. 3, though none reached critical temperatures. Drill no. 2 took the longest to reach the desired depth and displayed the most deformation. Findings highlight the importance of adhering to the recommended operational limits, suggesting that drills should be replaced after 15 cycles to ensure efficacy and patient safety. Full article

Dental implant bed preparation involves surgical drilling. Heat generated in this process can cause a temperature elevation beyond the bone damage limit (10 °C), affecting the osseointegration of the implant. Surgical templates ensure accurate implant placement, but they limit the access of the irrigation fluid. This study evaluated the hypothesis that surgical guides with internal cooling prevent bone heating more effectively than classical guides. To eliminate biological variability, this study was conducted on artificial bone pieces that mimic the bone density of the human mandible. We created a surgical template that incorporated four pairs of guides—one classical (CLA) and one with internal cooling (INT) in each pair. For each specimen, we randomly selected the type of surgical guide to start with and performed four osteotomies with a 2.7 mm-diameter drill; then, we widened each hole with a 3.3 mm drill and finalized it with a 3.7 mm drill. The temperature was recorded by thermocouples placed at 0.8 mm from the prospective edge of the final osteotomy. In 168 measurements (12 osteotomies on 14 specimens) conducted for each type of surgical guide, the mean temperature rise was 7.2 ± 4.9 °C (mean ± standard deviation) for CLA and 5.0 ± 3.8 °C for INT. The mean differences between temperature elevations were 1.5 °C, 2.1 °C, and 3.0 °C for the first, second, and third drill, and they were statistically significant: the p-values of Student’s t-test were 0.004, 0.01, and 0.001, respectively. Although the mean temperatures remained safe, temperature rises exceeded 10 °C in 23.8% (9.5%) of the osteotomies performed in the presence of CLA (INT). Taken together, our results suggest that surgical guides with internal cooling ensure a significant drop in the temperature rise caused by implant site drilling. Full article

Background: Osseointegration is fundamental to achieving successful implant therapy in dentistry. However, the heat generated during implant placement emerges as a critical factor predisposing to implant failure. Objective: This study aimed to analyze the different factors related to heat generation during implant placement, offering insights to clinicians in their daily clinical practice. Methods: Utilizing the PubMed, Web of Science, and Embase databases, we conducted an electronic search for articles published between January 2013 and December 2023. The analysis focused on several factors including bone type, drill shape, drill speed, drill material, drilling force, osteotomy depth, drill load, drilling technique (intermittent or continuous), presence of a surgical guide, irrigation methods, drill wear, and preparation tools available. Results: Initially, 2525 records were identified. After applying the inclusion and exclusion criteria and full-text assessment, 93 articles were included in this scoping review. Additionally, some articles published before 2013 were incorporated in the bibliography to ensure completeness of the review. Conclusions: Heat generation during implant placement arises from a complex interplay of multiple factors. While irrigation and bone hardness appear to be crucial determinants of heat generation during the osteotomy phase, the involvement of other factors remains less clear. Further studies are needed to better understand the precise contribution of these factors towards increasing temperature at the implant site. Full article

This pictorial essay aims to navigate through the complexities and challenges of renal transplantation (RT), by weaving together visual imagery with clinical insights within a comprehensive illustrative surgical guide. Herein, we provide a detailed visual exploration of the intricate anatomy and surgical processes necessary for both renal graft retrieval from the donor and also for an adequate implantation in the recipient. Regarding graft retrieval, after reviewing the relevant retroperitoneal surgical anatomy, and donor nephrectomy techniques, graft preservation and optimal backbench graft dissection principles were meticulously analyzed. Thereafter, the recipient surgical strategy for graft implantation was addressed, focusing on preoperative preparations, the site of implantation selection, exposure, operative bed dissection, graft revascularization, and urinary tract reconstruction. Careful donor and recipient selection, meticulous surgical execution, and rigorous postoperative management clearly hold a pivotal role in optimizing patient outcomes. Fostering a deeper understanding of the surgical nuances and clinical management practices that contribute to successful results post-RT, we hope to provide a useful practical tool for clinicians about to embark on the treacherous road of RT surgery. Innovative technologies and surgical practices that have already significantly improved the safety and effectiveness of RT stand testament to the importance of further scientific inquiry, conceptual developments, and clinical integration. Moving forward, it is essential that the medical community continues to refine these strategies and advocate for equitable access to transplantation, ensuring that advancements in the field translate into real-world benefits for all patients grappling with ESRD. The collaborative efforts of multidisciplinary teams are essential in addressing the complex clinical challenges associated with RT, with the ultimate goal of improving patient survival, enhancing graft longevity, and reducing healthcare disparities. Full article

Urinary tract diseases are common in cats, and often require surgical reconstruction. Here, to explore the possibility of urinary tract reconstruction in cats using in-body tissue architecture (iBTA), biosheets fabricated using iBTA technology were implanted into the feline bladder and the regeneration process was histologically evaluated. The biosheets were prepared by embedding molds into the dorsal subcutaneous pouches of six cats for 2 months. A section of the bladder wall was removed, and the biosheets were sutured to the excision site. After 1 and 3 months of implantation, the biosheets were harvested and evaluated histologically. Implantable biosheets were formed with a success rate of 67%. There were no major complications following implantation, including tissue rejection, severe inflammation, or infection. Urinary incontinence was also not observed. Histological evaluation revealed the bladder lumen was almost entirely covered by urothelium after 1 month, with myofibroblast infiltration into the biosheets. After 3 months, the urothelium became multilayered, and mature myocytes and nerve fibers were observed at the implantation site. In conclusion, this study showed that tissue reconstruction using iBTA can be applied to cats, and that biosheets have the potential to be useful in both the structural and functional regeneration of the feline urinary tract. Full article