Bone Reduction Research Articles

Indirect sinus lift with implant placement in maxillary right molar region

The maxilla has one of the least dense bone masses in the oral cavity and is composed of porous bone. Due to considerable alveolar bone resorption brought on by periodontal disease-induced tooth loss, there is an emphasis on bone reduction in both height and width. Pneumatization of the maxillary sinus, post-extraction bone resorption, and low-quality remaining alveolar bone all contribute to the difficulty in bone remodelling.Indirect sinus augmentation is an effective solution for this problem. This case report presents the rehabilitation of maxillary right first molar by using indirect sinus lift with implant placement where the bone height and bone width was compromised.

Revolutionizing Bone Regeneration with Grinder-Based Dentin Biomaterial: A Systematic Review.

Bone tissue regeneration is a critical aspect of dental surgery, given the common occurrence of bone resorption leading to alveolar bone defects. The aim of this paper was to conduct a systematic review to provide a comprehensive summary of the evidence regarding the regenerative properties of dentin biomaterial. This systematic review was conducted through comprehensive searches in the PubMed, Scopus, and Web of Science databases, as well as an extensive exploration of the gray literature sources, including WorldCat, The New York Academy of Medicine Library, and Trip Database, following the established PRISMA protocol. Keywords such as tooth, dentin, grinder, and autograft guided the search, with a focus on a standardized procedure involving dentin grinders within laboratory, experimental, and clinical settings. Initially, a pool of 1942 articles was identified with 452 duplicates removed. An additional 1474 articles were excluded for not aligning with the predefined topics, and three more were excluded due to the unavailability of the full text. Ultimately, 13 articles met the strict inclusion criteria and were included in the review. The chemical composition of the dentin particles was similar to natural bone in terms of oxygen, carbon, calcium, phosphorus, sodium, and magnesium content, as well as in terms of the Ca/P ratio. In addition, the dentin also contained amide I and amide II structures, as well as aliphatic and hydroxyl functional groups. The chemically treated dentin was free of microorganisms. The dentin had characteristic tubules that opened after chemical treatment. At the cellular level, dentin released bone morphogenetic protein 2, induced significant cell growth, and stimulated the reorganization of the fibroblast cytoskeleton. Most clinical studies have focused on alveolar bone regeneration. After the transplantation of demineralized dentin particles, studies have observed new bone formation, a reduction in residual bone, and an increase in connective tissue. Clinical reports consistently indicate uncomplicated healing and recovery post-transplantation. However, there is a notable gap in the evidence concerning complication rates, patient-reported outcomes, and the presence of pro-inflammatory factors. In conclusion, dentin biomaterial emerges as a versatile bone substitute, demonstrating high biocompatibility and ease of acquisition. The preservation of its internal structure containing organic matter and growth factors enhances its potential for effective bone regeneration. Particularly, in dental surgery, dentin-derived materials present a promising alternative to traditional autologous bone autografts, offering the potential to reduce patient morbidity and treatment costs.

Hump Rasping Using Powered Instruments: A Retrospective Review.

Nasal hump reduction, a common procedure in rhinoplasty, aims to create a harmonious nasal appearance with smooth dorsal lines. An alternative to traditional osteotomes is the carbide-tip nasal rasp, effective in eliminating modest contour deformities. However, the broad movements and physical forces of manual rasping can significantly weaken the osseocartilaginous vault. Power-assisted instruments have been used to reduce soft tissue trauma. Although long-term clinical outcomes of power-assisted instrumentation are pending, initial reports have been positive. This retrospective chart review encompassed 220 consecutive rhinoplasty cases conducted by the senior author, all involving women aged 19-37 years. Excluding 80 cases that did not involve bone reduction, the analysis concentrated on 140 patients who underwent bone reduction procedures. The success of nasal hump reduction was evaluated based on the joint satisfaction of both the patient and the surgeon with the surgical improvement. The open rhinoplasty approach was predominantly used for surgical exposure to minimize inadvertent rasping of the nasal cartilage. Among the 140 patients undergoing power-assisted bone removal, all but five achieved an initially satisfactory refinement of the bony nasal contour. Notably, no serious complications were observed throughout the study. Unfortunately, one patient did not comply with the monthly steroid injections, leading to the necessity of revision surgery for the removal of regenerated bone. The integration of power-assisted instrumentation in rhinoplasty procedures represents a promising advancement, addressing challenges associated with traditional methods.

Which type of supra-syndesmal fractures Weber C or Equivalent Weber C have the best reduction of the distal tibio-fibular syndesmosis? A prospective CT-scan investigation on 60 ankles

IntroductionThe reduction of the distal tibiofibular syndesmosis (SyTFd) is a crucial factor in the functional prognosis following a suprasyndesmotic ankle fracture. Few studies have compared, using computed tomography (CT), the quality of SyTFd reduction in Weber C ankle fractures (WebC) and Equivalent Weber C (EqWebC) fractures, where there is a medial ligament injury instead of a bony malleolar lesion. This CT-based study aimed to answer the following questions: (1) Do Weber C fractures allow for better reduction of the distal tibiofibular syndesmosis compared to Equivalent Weber C fractures? (2) Are the functional outcomes one year postoperatively better for Weber C fractures compared to Equivalent Weber C fractures? HypothesisThe hypothesis was that WebC fractures would present better reduction of the SyTFd than EqWebC fractures due to the restoration of bone anatomy, considering the bony nature of the medial ligament involvement. Materials and methodsSince December 2021, all patients presenting with an ankle fracture were included in a database. Suprasyndesmotic fractures were extracted, and between December 2021 and February 2022, 60 patients underwent surgery for a suprasyndesmotic fracture (28 WebC – 32 EqWebC). All patients were operated on using the same technique and underwent a postoperative bilateral CT scan in axial slices with both ankles in a neutral position (foot at 90 ° to the leg). An analysis of 8 measurements was performed under the same conditions. Each fractured ankle was compared to the healthy contralateral ankle, and a delta was obtained for each measurement. The follow-up was standardized. At one year, an AOFAS Score and a Maryland Foot Score (MFS) were recorded. Statistical differences between the two groups were measured using the Student's t-test and Chi-square test. ResultsThere was a significant difference between the WebC and EqWebC groups for clinical scores at one year postoperatively: AOFAS: 92.0 ± 6.3 [78–100] vs. 80.1 ± 5.4 [62–100], p < 0.05; MFS: 90.9 ± 6.4 [78–100] vs. 81.6 ± 5.2 [64–100], p < 0.05. CT scan analysis of the SyTFd reduction found significantly better reduction in the WebC group. DiscussionWebC fractures showed better clinical scores associated with better SyTFd reduction on postoperative CT scans. The anatomical reduction related to the bone reduction criteria during surgery could explain our findings. Level of evidenceIII; Case-Control Comparative Study.

Degenerative and regenerative peripheral processes are associated with persistent painful chemotherapy-induced neuropathies in males and females

This study investigated the time course of gene expression changes during the progression of persistent painful neuropathy caused by paclitaxel (PTX) in male and female mouse hindpaws and dorsal root ganglia (DRG). Bulk RNA-seq was used to examine these gene expression changes at 1, 16, and 31 days post-last PTX. At these time points, differentially expressed genes (DEGs) were predominantly related to the reduction or increase in epithelial, skin, bone, and muscle development and to angiogenesis, myelination, axonogenesis, and neurogenesis. These processes are accompanied by the regulation of DEGs related to the cytoskeleton, extracellular matrix organization, and cellular energy production. This gene plasticity during the progression of persistent painful neuropathy could be interpreted as a biological process linked to tissue regeneration/degeneration. In contrast, gene plasticity related to immune processes was minimal at 1–31 days after PTX. It was also noted that despite similarities in biological processes and pain chronicity between males and females, specific DEGs differed dramatically according to sex. The main conclusions of this study are that gene expression plasticity in hindpaw and DRG during PTX neuropathy progression similar to tissue regeneration and degeneration, minimally affects immune system processes and is heavily sex-dependent at the individual gene level.

Bone Mineral Density in Survivors of Childhood Cancer: A Meta-Analysis.

There is an increasing population of childhood cancer survivors (CCS) at risk for treatment-related toxicities, including skeletal morbidities. Bone mineral density (BMD) is a proxy for bone health and reductions are associated with osteoporosis and fractures. To investigate bone health in CCS by conducting a systematic review and meta-analysis of BMD after completed treatments. We searched Medline, Embase, Cochrane, and Web of Science in May 2019 and updated in May 2023. Studies reporting BMD Z-scores measured with dual-energy x-ray absorptiometry in CCS after treatment completion. We performed a pooled analysis of studies reporting BMD Z-scores and thereafter we analyzed studies comparing BMD in survivors and healthy controls. All analyses were performed based on the site of BMD measurement. Of 4243 studies, 84 were included (N = 8106). The mean time off-treatment across the studies ranged from 2 months to 24 years. The overall pooled mean Z-score was -0.57 (95% confidence interval [CI] -0.59 to -0.55) in the whole-body, -0.84 (95% CI -0.86 to -0.83) in the lumbar spine, -0.79 (95% CI -0.81 to -0.77) in the femoral neck and -0.14 (95% CI -0.18 to -0.11) in the total hip. When comparing survivors with controls, BMD was significantly lower in survivors at all sites. English publications, study-level meta-analysis. We showed a significant reduction of BMD Z-scores in CCS. Given the increased fracture risk already within -1 SD, these results emphasize the need for BMD surveillance and secondary prevention in CCS.

3D virtual patient-Magnetically retained printed stackable system for implant guided placement: Case report.

The aim of this report is to present the complete workflow of 3D virtual patient for planning and performing implant surgery with magnetically retained 3D-printed stackable guides. A 3D-printed stackable system was proposed based on bone, dental, and facial references. Initially, a 66-year-old male patient was digitalized through photographs, cone beam computed tomography, and intraoral scans (Virtuo Vivo, Straumann). All files were merged to create a 3D virtual patient in the planning software (coDiagnostiX, Straumann). Sequential stackable guides were designed, printed, and cured. Magnets were inserted into connectors, and the interim protheses received color characterization. Four mounted guides were produced for the specific purposes of pin fixation, bone reduction, implant placement, and immediate provisionalization. After surgery and healing period, patient digital data were updated. Final implantpositions were compared to planned values and inconsistencies were clinically acceptable. The mean angular deviation was 5.4° (3.2-7.3) and mean 3D discrepancies were of 0.90 mm (0.46-1.12) at the entry point and 1.68 mm (1.00-2.20) at implant apex. Case follow-up revealed stability, patient's comfort, and no intercurrences. Magnetically retained stackable guides provide treatment accuracy and reduce surgical and prosthetic complications. The projected virtual patient enhances decision-making and communication between the multidisciplinary team and the patient, while decreases time and costs. Bidimensional diagnosis and freehand implant placement have limitations and outcomes often rely on professionals' expertise. Performing facially driven virtual planning improves treatment predictability. This approach promotes function, esthetic harmony, and patient satisfaction. Implant guided surgery and 3D printed prostheses constitute a reproducible digital workflow that can be implemented into clinical practice to optimize dental care.

Effects of intentional early dense‐polytetrafluoroethylene membrane removal on vertical ridge augmentation

AbstractBackgroundVertical ridge augmentation (VRA) requires long healing times for bone maturation. This case study deals with the intentional early removal of a titanium‐reinforced dense polytetrafluoroethylene (TR‐dPTFE) membrane that allowed for treatment times reduction and improvement of bone quality.MethodsA TR‐dPTFE membrane was used for VRA in the premolar region of the upper right maxilla. The defect was filled with a mix of particulate autogenous bone and porcine xenograft in a 1:1 ratio. After a 4‐month uneventful healing period, the membrane was removed, and the thick keratinized palatal tissue was moved toward the buccal side via a pedicle flap. Implants insertion and healing abutments application were carried out 3 months later, when bone graft could have been revascularized and nourished by the periosteum.ResultsThe histologic evaluation of a bone sample harvested during implant bed preparation revealed a huge amount of mature newly formed bone even in the most coronal part. Two screw‐retained crowns were delivered 2 months after implant insertion and the 3.5‐year follow‐up showed perfectly maintained hard and soft tissues.ConclusionsIntentional early removal of TR‐dPTFE membrane after a 4‐month healing time, with simultaneous soft tissue augmentation via a buccally reposioned pedicle flap, allowed graft revascularization from the periosteum, and resulted in optimal quantity and quality of the regenerated bone. This process shortened the overall treatment times, taking only 9 months from VRA to prosthetic loading. Both augmented hard and soft tissues allowed for crestal bone maintenance around implants.Key points Titanium‐reinforced dense polytetrafluoroethylene (TR‐dPTFE) membranes, due to their closed structure, do not allow the passage of cells and vessels from the periosteum, and revascularization from the residual bone alone is not enough for proper graft maturation and long‐term crestal bone maintenance. Early removal of TR‐dPTFE membrane allows graft revascularization from the periosteum, and results in optimal quantity and quality of the regenerated bone. Increasing the thickness of the soft tissues, increasing the width of the keratinized mucosa, and repositioning the mucogingival line, via a free gingival graft or a pedicle flap, should be performed simultaneously in the membrane removal phase to reduce the number of surgical interventions, decrease patient morbidity, and shorten the total treatment time.

Untargeted metabolomics revealed the mechanism of aucubin on glucocorticoid-induced osteoporosis in mice through modulating arachidonic acid metabolism

Glucocorticoid-induced osteoporosis (GIOP) represents the most prevalent form of secondary osteoporosis. Aucubin (AU), a principal active component found in traditional herbal medicines such as Eucommia ulmoides, has been demonstrated to enhance osteoblast differentiation. Nonetheless, the precise therapeutic effects of AU on GIOP and the complex underlying regulatory mechanisms warrant further investigation. We first established a GIOP model in female mice and then assessed the therapeutic effects of AU using micro-CT analysis, biomechanical testing, measurements of serum calcium (Ca) and phosphorus (P) levels, and histological analyses using Hematoxylin and Eosin (HE) and Masson staining. Subsequently, non-targeted metabolomics was employed in order to study the effects of AU on serum metabolites in GIOP mice. The levels of the factors related to these metabolites were quantified using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blot analyses. Finally, the effects of AU on osteoblastic and osteoclastic differentiation were examined. We found that AU significantly ameliorated bone microarchitecture and strength in GIOP mice. It mitigated pathological damages such as impairment of trabecular bone structure and reduction in collagen fibers, while concurrently elevating serum levels of Ca and P. Non-targeted metabolomics revealed that Arachidonic acid (AA) metabolism serves as a common pathway between the control and GIOP groups, as well as between the high-dose AU (AUH) and GIOP groups. AU notably upregulates prostaglandin-endoperoxide synthase 2 (PTGS2) and microsomal prostaglandin-E synthase 1 (PTGES) expression and downregulates prostaglandin-H2 D-isomerase (PTGDS) expression. Furthermore, AU treatment increased the expression of runt-related transcription factor 2 (Runx2) and transcription factor Sp7 (Osterix), enhanced serum alkaline phosphatase (ALP) activity, and reduced osteoclast expression. These results indicate that AU is a potential drug for treating GIOP, and its mechanism is related to regulating AA metabolism and promoting osteoblast differentiation. However, the key targets of AU in treating GIOP still need further exploration.

Plate Fixation of Hamate Fractures in Fourth and Fifth Carpometacarpal Fracture Dislocations.

Traumatic dislocations of the fourth and fifth metacarpals, in conjunction with dorsal hamate fractures, are a common entity that can lead to the instability of the fourth and fifth carpometacarpal (CMC) joints. The fracture of the hamate, usually in a coronal dorsal shear configuration, can lead to the dorsal subluxation of the hamatometacarpal joint. Open reduction and internal fixation of the hamate bone with a dorsally applied buttress plate can re-establish a stable and congruent joint surface and anatomically align the articular surfaces of the small and ring finger CMC joints. We present a technique of internal fixation of the hamate to facilitate the reduction of the hamatometacarpal joints. Using a dorsal approach centered over the fourth and fifth CMC joints, the joint surfaces are directly visualized and subsequent fixation of the hamate is performed using a 1.3-mm T-plate to securely buttress its articular surface. This technique presents an approach to the multifaceted injury pattern of fourth and fifth CMC dislocations associated with a hamate fracture.

Tibio-Talo-Calcaneal Arthrodesis: Evaluation of the Effectiveness of a Specific Surgical Technique in 17 Cases.

Ankle arthrodesis is a crucial surgical intervention for advanced hindfoot conditions, aiming to restore plantigrade walking and alleviate pain. This study evaluates the effectiveness of a specific surgical approach for tibiotalocalcaneal arthrodesis (TTCA), focusing on rigorous risk factor control, corticocancellous grafting, and internal fixation using an angled retrograde femoral nail in the sagittal plane, and assesses the outcomes of this approach in terms of bone fusion and reduction of postoperative complications. This retrospective analysis includes 17 patients who underwent TTCA in a trauma-orthopedic department over seven years. Data were collected from medical records, the HOSIX software, and patient consultations. Preoperative assessments, surgical techniques, postoperative care, and follow-up evaluations were documented. The mean age of patients was 42.4 years, with a male predominance. Surgical indications included post-traumatic arthropathy (53%), inflammatory arthropathy, ankle infectious pathologies, and Charcot footand ankle prosthesis failures. All patients underwent standard preoperative evaluations and received corticocancellous grafts. An angled retrograde femoral nail in the sagittal plane was used for internal fixation. Postoperative immobilization lasted 6 to 8 weeks, with subsequent rehabilitation. The bone fusion rate was 100%, with a low complication rate (23.5%). Our study showed a younger patient population with a male predominance, different from some previous studies. Surgical techniques, including the anterior approach combined with a lateral subtalar approach, were consistent with some studies but differed from others. Corticocancellous grafts and the angled retrograde femoral nail in the sagittal plane demonstrated favorable outcomes in terms of fusion. Complication rates were lower compared to some previous reports, highlighting potential improvements in postoperative management. The surgical approach described for TTCA, emphasizing rigorous risk factor control, corticocancellous grafting, and internal fixation using an angled retrograde femoral nail in the sagittal plane, led to satisfactory bone fusion and reduced postoperative complications. These results underscore the importance of this approach in achieving optimal functional outcomes in ankle arthrodesis.

Concentrated growth factor and collagen as barrier materials in alveolar ridge preservation for posterior teeth: a prospective cohort study with one-year follow-up.

This study aims to evaluate the efficacy of concentrated growth factor (CGF) membrane and collagen as barrier materials in sealing the alveolar socket in alveolar ridge preservation (ARP) in the posterior region during a one-year follow-up. A total of 24 patients who underwent ARP in the posterior region were selected for inclusion and randomly assigned to the CGF group (12 cases) and Collagen group (12 cases). The patients in both groups underwent extraction of posterior teeth. The extraction sockets were filled with a bone substitute to the level of the pre-extraction buccal and lingual or palatal alveolar bone plates. The wounds in the CGF group were closed with a fabricated CGF overlaying the upper edge of the bone substitute material, whereas those in the Collagen group were closed with Bio-Oss Collagen. The implants were placed after 6 months. The evaluation was based on implant retention, re-grafting rate, and vertical and horizontal alveolar ridge bone volume changes measured by cone beam computed tomography (CBCT). Data were statistically analyzed using SPSS 28.0 software. No patient withdrew throughout the follow-up period. No implant failure and no severe peri-implant or mucosal soft tissue complications were observed. Six months after the operation, the degree of vertical alveolar ridge height resorption in the CGF group was lower than that in the Collagen group (P<0.05). There were no statistically difference between the groups at 1 year after the operation (P>0.05). The amount of bone reduction in horizontal alveolar ridge width showed no difference between the groups at 6 months and 1 year after surgery (P>0.05). CGF membrane and Bio-Oss Collagen as barrier materials for posterior ARP inhibited reduction in alveolar ridge bone mass.

Irisin prevents trabecular bone damage and tumor invasion in a mouse model of multiple myeloma

Abstract Bone disease associated with multiple myeloma (MM) is characterized by osteolytic lesions and pathological fractures, which remain a therapeutic priority despite new drugs improving MM patient survival. Antiresorptive molecules represent the main option for the treatment of MM-associated bone disease (MMBD), whereas osteoanabolic molecules are under investigation. Among these latter, we here focused on the myokine irisin, which is able to enhance bone mass in healthy mice, prevent bone loss in osteoporotic mouse models, and accelerate fracture healing in mice. Therefore, we investigated irisin effect on MMBD in a mouse model of MM induced by intratibial injection of myeloma cells followed by weekly administration of 100 μg/kg of recombinant irisin for 5 wk. By micro-Ct analysis, we demonstrated that irisin improves MM-induced trabecular bone damage by partially preventing the reduction of femur Trabecular Bone Volume/Total Volume (P = .0028), Trabecular Number (P = .0076), Trabecular Fractal Dimension (P = .0044), and increasing Trabecular Separation (P = .0003) in MM mice. In cortical bone, irisin downregulates the expression of Sclerostin, a bone formation inhibitor, and RankL, a pro-osteoclastogenic molecule, while in BM it upregulates Opg, an anti-osteoclastogenic cytokine. We found that in the BM tibia of irisin-treated MM mice, the percentage of MM cells displays a reduction trend, while in the femur it decreases significantly. This is in line with the in vitro reduction of myeloma cell viability after 48 h of irisin stimulation at both 200 and 500 ng/mL and, after 72 h already at 100 ng/mL rec-irisin. These results could be due to irisin ability to downregulate the expression of Notch 3, which is important for cell-to-cell communication in the tumor niche, and Cyclin D1, supporting an inhibitory effect of irisin on MM cell proliferation. Overall, our findings suggest that irisin could be a new promising strategy to counteract MMBD and tumor burden in one shot.

Titanium dioxide nanoparticles oral exposure induce osteoblast apoptosis, inhibit osteogenic ability and increase lipogenesis in mouse

Titanium dioxide nanoparticles (TiO2-NPs) are widely used in food, paint, coating, cosmetic, and composite orthodontic material. As a common food additive, TiO2-NPs can accumulate in various organs of human body, but the effect and underlying mechanism of bone remain unclear. Here mice were exposed to TiO2-NPs by oral gavage, and histological staining of femoral sections showed that TiO2-NPs reduced bone formation and enhanced osteoclast activity and lipogenesis, contributing to decreased trabecula bone. Transmission electron microscope (TEM) as well as biochemical and flow cytometry analysis of osteoblast exhibited that TiO2-NPs accumulated in osteoblast cytoplasm and impaired mitochondria ultrastructure with increased reactive oxygen species (ROS) and lipid hyperoxide, resulting in osteoblast apoptosis. In terms of mechanism, TiO2-NPs treatment inhibited expression of AKT and then increased pro-apoptotic protein Bax expression which was failure to form heterodimers with decreased anti-apoptotic Bcl-2, activating downstream Caspase-9 and Caspase-3 and inducing apoptosis. Additionally, TiO2-NPs suppressed Wnt3a level and then activated anti-Glycogen synthesis kinase (GSK-3β) phosphorylation, and ultimately resulted in degradation of β-catenin which down-regulated Runt-related transcription factor 2 (Runx2) and Osterix, inhibiting expression of osteogenic related proteins. Together, these results revealed that exposure of TiO2-NPs induced apoptosis and inhibited osteoblast differentiation through suppressing PI3K/AKT and Wnt/β-catenin signaling pathways, resulting in reduction of trabecula bone.

A New Full Digital Workflow for Fixed Prosthetic Rehabilitation of Full-Arch Edentulism Using the All-on-4 Concept.

(1) Background: Recent digital workflows are being developed for full-arch rehabilitations supported by implants with immediate function. The purpose of this case series is to describe a new digital workflow for the All-on-4 concept. (2) Methods: The patients were rehabilitated using the All-on-4 concept with a digital workflow including computerized tomography scanning, intra-oral scanning, and CAD-CAM production of the temporary prosthesis, with the 3D printing of stackable guides (base guide, implant guide, and prosthetic guide). The passive fit of the prostheses and the time to perform the rehabilitations were evaluated. (3) Results: The digital workflow allowed for predictable bone reduction, the insertion of implants with immediate function, and the connection of an implant-supported prosthesis with immediate loading. The time registered to perform the full-arch rehabilitations (implant insertion, abutment connection, prosthesis connection) was below 2 hours and 30 min. No passive fit issues were noted. (4) Conclusions: within the limitation of this case series, the digital workflow applied to the All-on-4 concept using stackable base-, implant-, and prosthetic guides constitutes a potential alternative with decreased time for the procedure without prejudice of the outcome.

Long-Term Volumetric Stability of Maxillary Sinus Floor Augmentation Using a Xenograft Bone Substitute and Its Combination with Autologous Bone: A 6+ Year Retrospective Follow-Up Study Using Cone Beam Computed Tomography.

Deproteinised bovine bone (DBB) is widely used as bone substitute in maxillary sinus floor augmentation (MSFA) surgery. No previous studies have shown the long-term volumetric changes in the augmented bone when using DBB. The selected patients had MFSA performed using a lateral window technique and a xenograft, alone or in combination with the patient's autologous bone from the mandible. Cone beam computed tomography (CBCT) images were used to compare the volumetric changes in the augmented bone for patients over a period of 6 or more years. No significant bone reduction was seen in the augmented bone region when comparing MSFA after 7 months and 6 or more years after dental implantation.

LASER-ASSISTED CROWN LENGTHENING: CLINICAL EFFICACY AND ADVANTAGES OVER CONVENTIONAL TECHNIQUES (SYSTEMATIC REVIEW)

Introduction: Crown lengthening is a widely recognized dental procedure with both aesthetic and functional purposes. It involves the reduction of periodontal hard and soft tissues to obtain supracrestal tooth length, resulting in longer clinical crowns and adequate supracrestal tissue attachment. Laser therapy has emerged as a promising alternative that is currently developing in the field of periodontics and offers several advantages. This review aims to synthesize the current research on the clinical efficacy of laser-assisted crown lengthening procedures and highlight their advantages over conventional methods. Review: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive search was conducted in electronic databases PubMed, Scopus, Embase, and Google Scholar for human studies published from 2017 to April 2023. Out of 213 identified and screened studies, three original articles were included in the analysis. Two clinical trial studies used Er,Cr:YSGG while one study used Er:YAG for crown lengthening procedures involving gingiva and alveolar bone reduction, with a 3-month follow-up period. Compared to conventional crown lengthening, the laser-assisted approach showed comparable increases in clinical crown length. However, the laser-assisted group demonstrated better gingival margin stability, improved soft tissue healing, and minimal damage to adjacent tissues. Furthermore, there was a statistically significant lower bacterial load and less post-surgery pain with laser-assisted crown lengthening compared to the conventional method. Conclusion: In cases where both gingival and bone reduction are required, laser-assisted crown lengthening using Er,Cr:YSGG and Er:YAG can be considered a minimally invasive alternative with several advantages over conventional procedures.

Nerve growth factor receptor limits inflammation to promote remodeling and repair of osteoarthritic joints

Osteoarthritis (OA) is a painful, incurable disease affecting over 500 million people. Recent clinical trials of the nerve growth factor (NGF) inhibitors in OA patients have suggested adverse effects of NGF inhibition on joint structure. Here we report that nerve growth factor receptor (NGFR) is upregulated in skeletal cells during OA and plays an essential role in the remodeling and repair of osteoarthritic joints. Specifically, NGFR is expressed in osteochondral cells but not in skeletal progenitor cells and induced by TNFα to attenuate NF-κB activation, maintaining proper BMP-SMAD1 signaling and suppressing RANKL expression in mice. NGFR deficiency hyper-activates NF-κB in murine osteoarthritic joints, which impairs bone formation and enhances bone resorption as exemplified by a reduction in subchondral bone and osteophytes. In human OA cartilage, NGFR is also negatively associated with NF-κB activation. Together, this study suggests a role of NGFR in limiting inflammation for repair of diseased skeletal tissues.

Morphological and Immunohistochemical Characterization of Bone Structure and Cell–Cell Communication in a Rat Osteoporosis Model

Bone remodeling is essential for maintaining bone health. The imbalance between bone formation and bone resorption leads to bone diseases such as osteoporosis. Connexin43 (Cx43) is a gap junction molecule that plays an important role in bone homeostasis. The present study investigates the morphological characteristics of bone trabeculae and the distribution of Cx43 in bone cells using osteoporotic rat models to explore the relationship between osteoporosis and bone remodeling. Female Sprague–Dawley rats were divided into three groups: sham, ovarectomy with food deprivation (OVX+diet), and ovarectomy with steroid administration (OVX+steroid) for 3 and 12 months to induce osteoporosis. The lumbar vertebrae were processed for histomorphometric and immunohistochemical evaluation of the trabeculae and the distribution of Cx43 in bone cells. The data showed a significant reduction in trabecular bone in both osteoporotic groups. After 12 months, the OVX+diet treatment resulted in reduced mineralization and an increase in unmineralized bone. The percentage of alkaline phosphatase-positive areas in the OVX+diet vertebrae was lower at 12 months compared to the sham group. A significant increase in tartrate-resistant acid phosphatase (TRAP) positive osteoclasts was observed in the OVX+diet group. Both osteoporotic groups showed a decrease in Cx43-positive osteoblasts areas. An increase in the number of osteoclasts positive for Cx43 was detected in the OVX+diet group. The changes in Cx43 distribution in bone cells, together with trabecular mineralization, suggest that Cx43 may play a role in the progression of osteoporosis and could be a valuable target to improve bone remodeling.

Fossils document evolutionary changes of jaw joint to mammalian middle ear.

The dual jaw joint of Morganucodon1,2 consists of the dentary-squamosal joint laterally and the articular-quadrate one medially. The articular-quadrate joint and its associated post-dentary bones constitute the precursor of the mammalian middle ear. Fossils documenting the transition from such a precursor to the mammalian middle ear are poor, resulting in inconsistent interpretations of this hallmark apparatus in the earliest stage of mammaliaform evolution1-5. Here we report mandibular middle ears from two Jurassic mammaliaforms: a new morganucodontan-like species and a pseudotribosphenic shuotheriid species6. The morganucodontan-like species shows many previously unknown post-dentary bone morphologies1,2 and exhibits features that suggest a loss of load-bearing function in its articular-quadrate joint. The middle ear of the shuotheriid approaches the mammalian condition in that it has features that are suitable for an exclusively auditory function, although the post-dentary bones are still attached to the dentary. With size reduction of the jaw-joint bones, the quadrate shifts medially at different degrees in relation to the articular in the two mammaliaforms. These changes provide evidence of a gradual loss of load-bearing function in the articular-quadrate jaw joint-a prerequisite for the detachment of the post-dentary bones from the dentary7-12 and the eventual breakdown of the Meckel's cartilage13-15 during the evolution of mammaliaforms.