Clinical Efficacy of GBR Technique Combined with Temporary Bridgework-Guided Gingival Contouring in Treating Upper Anterior Tooth Loss with Labial Bone Defects

Objective:To investigate the clinical effect of the guided bone regeneration(GBR)technique combined with temporary bridgework-guided gingival contouring in treating upper anterior tooth loss with labial bone defects.Methods:From July 2023 to April 2024,80 patients with upper anterior tooth loss and labial bone defects were admitted to the hospital and selected as evaluation samples.They were divided into an observation group(n=40)and a control group(n=40)using a numerical table lottery scheme.The control group received treatment with the GBR technique,while the observation group received treatment with the GBR technique combined with temporary bridges to guide gingival contouring.The two groups were compared in terms of clinical red aesthetic scores(PES),labial alveolar bone density,labial bone wall thickness,gingival papillae,gingival margin levels,and patient satisfaction.Results:The PES scores of patients in the observation group were higher than those in the control group after surgery(P<0.05).The bone density of the labial alveolar bone and the thickness of the labial bone wall in the observation group were higher than those in the control group.The levels of gingival papillae and gingival margins were lower in the observation group after surgery(P<0.05).Additionally,patient satisfaction in the observation group was higher than in the control group(P<0.05).Conclusion:The GBR technique combined with temporary bridge-guided gingival contouring for treating upper anterior tooth loss with labial bone defects can improve the aesthetic effect of gingival soft tissue,increase alveolar bone density and the thickness of the labial bone wall,and enhance patient satisfaction.This approach is suitable for widespread application in healthcare institutions.

Customized scaffolds for large bone defects using 3D‑printed modular blocks from 2D‑medical images

Additive manufacturing(AM)has revolutionized the design and manufacturing of patient-specific,three-dimensional(3D),complex porous structures known as scaffolds for tissue engineering applications.The use of advanced image acquisition techniques,image processing,and computer-aided design methods has enabled the precise design and additive manufacturing of anatomically correct and patient-specific implants and scaffolds.However,these sophisticated techniques can be timeconsuming,labor-intensive,and expensive.Moreover,the necessary imaging and manufacturing equipment may not be readily available when urgent treatment is needed for trauma patients.In this study,a novel design and AM methods are proposed for the development of modular and customizable scaffold blocks that can be adapted to fit the bone defect area of a patient.These modular scaffold blocks can be combined to quickly form any patient-specific scaffold directly from two-dimensional(2D)medical images when the surgeon lacks access to a 3D printer or cannot wait for lengthy 3D imaging,modeling,and 3D printing during surgery.The proposed method begins with developing a bone surface-modeling algorithm that reconstructs a model of the patient’s bone from 2D medical image measurements without the need for expensive 3D medical imaging or segmentation.This algorithm can generate both patient-specific and average bone models.Additionally,a biomimetic continuous path planning method is developed for the additive manufacturing of scaffolds,allowing porous scaffold blocks with the desired biomechanical properties to be manufactured directly from 2D data or images.The algorithms are implemented,and the designed scaffold blocks are 3D printed using an extrusion-based AM process.Guidelines and instructions are also provided to assist surgeons in assembling scaffold blocks for the self-repair of patient-specific large bone defects.

Modified membrane fixation technique in a severe continuous horizontal bone defect:A case report

BACKGROUND Continuous severe horizontal bone defect is common in the aesthetic maxillary anterior area,and presents a major challenge in implant dentistry and requires predictable bone augmentation to increase the width of the alveolar bone.CASE SUMMARY A 24-year-old man,with a history of well-controlled IgA nephropathy,presented to the Dentistry Department of our hospital complaining of missing his right maxillary anterior teeth 1 mo ago.Severe horizontal alveolar bone defects at sites of teeth 12,13 and 14 were diagnosed.A modified guided bone regeneration surgical approach stabilizing the absorbable collagen membrane and particulate graft materials by periosteal diagonal mattress suture(PDMS)combined with four corner pins was used for this severe continuous horizontal bone defect.The outcome revealed that the newly formed alveolar ridge dimension increased from 0.72 mm to 11.55 mm horizontally 10 mo postoperatively,with no adverse events.The implant surgery was successfully performed.CONCLUSION This case highlights that PDMS combined with four corner pins is feasible to maintain the space and stabilize the graft and membranes in severe continuous horizontal bone defect.

A Case Report of Immediate Implant Placement Combined with Flap Surgery,Guided Bone Regeneration and Non-submerged Healing with a Labial Bone Wall Defect in the Esthetic Zone

[Basckground]This case report presented a methodology for immediate implantation in the esthetic zone with a facial bone defect along with flap surgery,guided bone regeneration,and non-submerged healing.[Case presentation]A 27-year-old female patient was complaining of the aesthetic complication that was caused via metallic staining of the neck of ceramic crowns in the maxillary right anterior region for one year.She has experienced immediate implantation along with flap surgery,guided bone regeneration(GBR),and non-submerged healing.The torque of the implant reached to the 35 N·cm to confirm primary stability.Six months after surgery,the healing abutment and the implant were fixed,the gingiva was healthy in the surgical area,and the nearby teeth and the opposite teeth were normal.[Results]The results of cone-beam computer tomography(CBCT)revealed that bone defects were filled with the newly formed bone.At the same time,the final impressions accomplished,and an all-ceramic crown was fit-placed.As a whole,the patient satisfaction rate was high.[Conclusions]Immediate implant placement with flap surgery,GBR,and non-submerged healing with a facial bone wall defect in the esthetic zone is an achievable process.

Surgical management of tegmen defects of the temporal bone and meningoencephalic herniation: our experience

1. Introduction The tegmental wall of the tympanic cavity is a thin plate of the temporal bone that separates the middle cranial fossa(MCF) from the ear. This anatomical region consists of two areas: an anterior one, comprised of the tegmen tympani(To′th et al., 2007), and a posterior one, formed by the tegmen antri and the tegmen mastoideum(Makki et al., 2011). In some patients, the tegmental region of the temporal bone can be interrupted, causing a tegmen defect(TD). A TD is sometimes associated with a meningoencephalic herniation(MEH), in which brain tissue herniates through a TD.

A Preliminary Mechanism Study on the Treatment of Rabbit Bone Defect Bone Nonunion with Xuduan Jiegu Decoction

Objective: To investigate the curative effect and mechanism of Xuduan Jiegu Decoction in the treatment of rabbit bone defect bone nonunion. Methods: The experiment was randomly divided into three groups;1) The control group that was given neither the modeling nor the treatment;2) The model group that was not given the treatment after the operation to model a bone defect;3) The treatment group that was given intermittent bone decoction after modeling (i.e., the operation), the dose was 105 g/piece, twice a day, for 4 consecutive weeks. For the three groups, Anterolateral X-rays of the left forearm were taken 14 days after the surgery to observe the bone nonunion healing with pretherapy and post-treatment. The expression levels of TGF-β, BMP-2 and VEGF in the blood of each group were measured by ELISA at 4 weeks after treatment. The peri-fracture histopathological changes between each group of pretherapy and post-treatment were evaluated by using tissue sections. Results: Compared with the control group, there was no obvious healing in the model group on the 14th day after the operation. Compared with the model group, the treatment group was treated with Xuduan Jiegu Decoction, and there was a trend of healing and callus formation on the 14th day. HE staining showed that the cells in the control group were closely arranged without any pathological changes. In the model group, the tissues around the fracture end were arranged loosely, and the cells were vacuolated and infiltrated by inflammatory cells. Compared with the model group, the peripheral cell arrangement was better and the peripheral lesions were reduced in the treatment group. The content of TGF-β, BMP-2 and VEGF in blood detected by ELISA was significantly higher in the treatment group than in the control group and the model group, with statistical significance. Conclusion: Xuduan Jiegu Decoction can promote callus formation and accelerate fracture healing in rabbit radius bone defect, and the mechanism of promoting fracture healing is related to the increases of TGF-β, BMP-2 and VEGF levels.

Update on the use of 45S5 bioactive glass in the treatment of bone defects in regenerative medicine

Bone regeneration is a critical area in regenerative medicine,particularly in orthopedics,demanding effective biomedical materials for treating bone defects.45S5 bioactive glass(45S5 BG)is a promising material because of its osteoconductive and bioactive properties.As research in this field continues to advance,keeping up-to-date on the latest and most successful applications of this material is imperative.To achieve this,we conducted a comprehensive search on Pub-Med/MEDLINE,focusing on English articles published in the last decade.Our search used the keywords“bioglass 45S5 AND bone defect”in combination.We found 27 articles,and after applying the inclusion criteria,we selected 15 studies for detailed examination.Most of these studies compared 45S5 BG with other cement or scaffold materials.These comparisons demonstrate that the addition of various composites enhances cellular biocompatibility,as evidenced by the cells and their osteogenic potential.Moreover,the use of 45S5 BG is enhanced by its antimicrobial properties,opening avenues for additional investigations and applications of this biomaterial.

Comparative study of chitosan/fibroin–hydroxyapatite and collagen membranes for guided bone regeneration in rat calvarial defects: micro-computed tomography analysis

This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. Fifty-four （54） rats were studied. A circular bony defect （8 mm diameter） was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group （n= 18）, the CFB-HAP membrane was used to cover the bony defect, and in the control group （n= 18）, a resorbable collagen membrane （Bio-Gide） was used. In the negative control group （n= 18）, no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume （BV） and bone mineral density （BMD） （P〈O.05） between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration （GBR） membrane.

Real-time-guided bone regeneration around standardized critical size calvarial defects using bone marrow-derived mesenchymal stem cells and collagen membrane with and without using tricalcium phosphate: an in vivo microcomputed tomographic and histologic e

The aim of the present real time in vivo micro-computed tomography （pCT） and histologic experiment was to assess the efficacy of guided bone regeneration （GBR） around standardized calvarial critical size defects （CSD） using bone marrow-derived mesenchymal stem cells （BMSCs）, and collagen membrane （CM） with and without tricalcium phosphate （TCP） graft material. In the calvaria of nine female Sprague-Dawley rats, full-thickness CSD （diameter 4.6 mm） were created under general anesthesia. Treatment-wise, rats were divided into three groups. In group 1, CSD was covered with a resorbable CM; in group 2, BMSCs were filled in CSD and covered with CM; and in group 3, TCP soaked in BMSCs was placed in CSD and covered with CM. All defects were closed using resorbable sutures. Bone volume and bone mineral density of newly formed bone （NFB） and remaining TCP particles and rate of new bone formation was determined at baseline, 2, 4, 6, and 10 weeks using in vivo pCT. At the lOth week, the rats were killed and calvarial segments were assessed histologically. The results showed that the hardness of NFB was similar to that of the native bone in groups I and 2 as compared to the NFB in group 3. Likewise, values for the modulus of elasticity were also significantly higher in group 3 compared to groups 1 and 2. This suggests that TCP when used in combination with BMSCs and without CM was unable to form bone of significant strength that could possibly provide mechanical ＂lock＂ between the natural bone and NFB. The use of BMSCs as adjuncts to conventional GBR initiated new bone formation as early as 2 weeks of treatment compared to when GBR is attempted without adiunct BMSC therapy.

3D Printing Hip Prostheses Offer Accurate Reconstruction,Stable Fixation,and Functional Recovery for Revision Total Hip Arthroplasty with Complex Acetabular Bone Defect

Complicated and large acetabular bone defects present the main challenges and difficulty in the revision of total hip arthroplasty(THA).This study aimed to explore the advantages of three-dimensional(3D)printing technology in the reconstruction of such acetabular bone defects.We retrospectively analyzed the prognosis of four severe bone defects around the acetabulum in three patients who were treated using 3D printing technology.Reconstruction of bone defect by conventional methods was difficult in these patients.In this endeavor,we used radiographic methods,related computer software such as Materialise's interactive medical image control system and Siemens NX software,and actual surgical experience to estimate defect volume,prosthesis stability,and installation accuracy,respectively.Moreover,a Harris hip score was obtained to evaluate limb function.It was found that bone defects could be adequately reconstructed using a 3D printing prosthesis,and its stability was reliable.The Harris hip score indicated a very good functional recovery in all three patients.In conclusion,3D printing technology had a good therapeutic effect on both complex and large bone defects in the revision of THA.It was able to achieve good curative effects in patients with large bone defects.

Structural bone allografts with intramedullary vascularized fibular autografts for the treatment of massive bone defects in extremities

Objective:To report the clinical outcome of repairing massive bone defects biologically in limbs by homeochronous using structural bone allografts with intramedullary vascularized fibular autografts. Methods: From January 2001 to December 2005, large bone defects in 19 patients (11 men and 8 women, aged 6 to 35 years) were repaired by structural bone allografts with intramedullary vascularized fibular autografts in the homeochronous period. The range of the length of bone defects was 11 to 25 cm (mean 17.6 cm), length of vascularized free fibular was 15 to 29 cm (mean 19.2 cm), length of massive bone allografts was 11 to 24 cm (mean 17.1 cm). Location of massive bone defects was in humerus(n=1), in femur(n=9) and in tibia(n=9), respectively. Results: After 9 to 69 months (mean 38.2 months) follow-up, wounds of donor and recipient sites were healed inⅠstage, monitoring-flaps were alive, eject reaction of massive bone allografts were slight, no complications in donor limbs. Fifteen patients had the evidence of radiographic union 3 to 6 months after surgery, 3 cases united 8 months later, and the remained one case of malignant synovioma in distal femur recurred and amputated the leg 2.5 months, postoperatively. Five patients had been removed internal fixation, complete bone unions were found one year postoperatively. None of massive bone allografts were absorbed or collapsed at last follow-up. Conclusion: The homeochronous usage of structural bone allograft with an intramedullary vascularized fibular autograft can biologically obtain a structure with the immediate mechanical strength of the allograft, a potential result of revascularization through the vascularized fibula, and accelerate bone union not only between fibular autograft and the host but also between massive bone allograft and the host.

Ilizarov bone transport combined with the Masquelet technique for bone defects of various etiologies (preliminary results)

BACKGROUND The Ilizarov bone transport(IBT)and the Masquelet induced membrane technique(IMT)have specific merits and shortcomings,but numerous studies have shown their efficacy in the management of extensive long-bone defects of various etiologies,including congenital deficiencies.Combining their strong benefits seems a promising strategy to enhance bone regeneration and reduce the risk of refractures in the management of post-traumatic and congenital defects and nonunion that failed to respond to other treatments.AIM To combine IBT and IMT for the management of severe tibial defects and pseudarthrosis,and present preliminary results of this technological solution.METHODS Seven adults with post-traumatic tibial defects(subgroup A)and nine children(subgroup B)with congenital pseudarthrosis of the tibia(CPT)were treated with the combination of IMT and IBT after the failure of previous treatments.The mean number of previous surgeries was 2.0±0.2 in subgroup A and 3.3±0.7 in subgroup B.Step 1 included Ilizarov frame placement and spacer introduction into the defect to generate the induced membrane which remained in the interfragmental gap after spacer removal.Step 2 was an osteotomy and bone transport of the fragment through the tunnel in the induced membrane,its compression and docking for consolidation without grafting.The outcomes were retrospectively studied after a mean follow-up of 20.8±2.7 mo in subgroup A and 25.3±2.3 mo in subgroup B.RESULTS The“true defect”after resection was 13.3±1.7%in subgroup A and 31.0±3.0%in subgroup B relative to the contralateral limb.Upon completion of treatment,defects were filled by 75.4±10.6%and 34.6±4.2%,respectively.Total duration of external fixation was 397±9.2 and 270.1±16.3 d,including spacer retention time of 42.4±4.5 and 55.8±6.6 d,in subgroups A and B,respectively.Bone infection was not observed.Postoperative complications were several cases of pin-tract infection and regenerate deformity in both subgroups.Ischemic regeneration was observed in two cases of subgroup B.Complications were corrected during the course of treatment.Bone union was achieved in all patients of subgroup A and in seven patients of subgroup B.One non-united CPT case was further treated with the Ilizarov compression method only and achieved union.After a follow-up period of two to three years,refractures occurred in four cases of united CPT.CONCLUSION The combination of IMT and IBT provides good outcomes in post-traumatic tibial defects after previous treatment failure but external fixation is longer due to spacer retention.Refractures may occur in severe CPT.

Selective serotonin re-uptake inhibitor sertraline inhibits bone healing in a calvarial defect model

Bone wound healing is a highly dynamic and precisely controlled process through which damaged bone undergoes repair and complete regeneration. External factors can alter this process, leading to delayed or failed bone wound healing. The findings of recent studies suggest that the use of selective serotonin reuptake inhibitors(SSRIs) can reduce bone mass, precipitate osteoporotic fractures and increase the rate of dental implant failure. With 10% of Americans prescribed antidepressants, the potential of SSRIs to impair bone healing may adversely affect millions of patients’ ability to heal after sustaining trauma. Here, we investigate the effect of the SSRI sertraline on bone healing through pre-treatment with(10 mg·kg-1sertraline in drinking water, n = 26) or without(control, n = 30) SSRI followed by the creation of a 5-mm calvarial defect. Animals were randomized into three surgical groups:(a) empty/sham,(b) implanted with a DermaMatrix scaffold soak-loaded with sterile PBS or(c) DermaMatrix soak-loaded with542.5 ng BMP2. SSRI exposure continued until sacrifice in the exposed groups at 4 weeks after surgery. Sertraline exposure resulted in decreased bone healing with significant decreases in trabecular thickness, trabecular number and osteoclast dysfunction while significantly increasing mature collagen fiber formation. These findings indicate that sertraline exposure can impair bone wound healing through disruption of bone repair and regeneration while promoting or defaulting to scar formation within the defect site.

Bovine Calcined Bone for the Repair of Radial Defect in a Rabbit Model

In order to investigate the bovine calcined bone's ability of repairing segmental bone defect and seek a new artificial bone substitute material, the bovine calcined bone (450℃,32 h) was implanted into the 10 mm middle radial defect of rabbits with tricalcium phosphate ceramics as the control. By using the methods of histology, radiology and biomechanics their osteogenic ability were measured. It was found that the bovine calcined bone's ability of repairing bone defect was better than that of tricalcium phosphate ceramics. The histological Nilsson′s scores at 3rd, 5th, 9th week after operation were significantly increased ( P <0.01). At 12th week after operation the bending strength of radius in experimental group was much higher than that of control group and turned normal. It was suggested that bovine calcined bone is an ideal artificial bone substitute material with good ability of repairing segmental bone defect and some degree of mechanical strength.

Meta analysis of Masquelet technology and Llizarov technology in the treatment of infectious bone defects

Objective: To systematically evaluate the clinical efficacy and safety of Masquelet technology and Llizarov group technology in the treatment of infectious bone defects by meta-analysis. Methods: The computer searched China Knowledge Network (CNKI), Wanfang, VIP, Chinese Biomedical Literature Database (CBM), Pubmed, Medline, Cochrane Llibrary databases. The retrieval time was from the time of the establishment of the database to January 2020. According to the inclusion and exclusion criteria, randomized controlled trials on the treatment of infectious bone defects using Masquelet technology and Llizarov technology were collected, and the retrieved literature was independently screened, evaluated, and data extracted by two researchers, and then RevMan5.3 software was used so for meta-analysis. Results: A total of 10 RCT documents were included, with a total of 496 patients, including 242 in the Masquelet group and 254 in the Llizarov group. The results of the meta-analysis showed that: in terms of bone defect healing time, total weight bearing time, treatment cost, and complication rate, the Masquelet group was significantly different from the Llizarov group, and the Masquelet group was better than the Llizarov group (P <0.05);In terms of knee joint Lowa score and SF-36 score, Masquelet group has significant differences compared with Llizarov group, Llizarov group is better than Masquelet group (P <0.05);in excellent rate, number of operations, ankle Lowa score, infection control rate In terms of excellent rate of affected limb function, there was no significant difference between Masquelet group and Llizarov group (P> 0.05). Conclusion:Compared with Llizarov technology, Masquelet technology has obvious advantages in the treatment of infectious bone defects in terms of bone defect healing time, total weight-bearing time, treatment cost, and complication rate. In terms of scoring, it has advantages over Masquelet technology, but in terms of excellent treatment rate, number of operations, and ankle lowa score. In terms of infection control rate and excellent function of affected limbs, there was no significant difference between Masquelet technology and Llizarov technology,However, due to the low quality of the included studies and the small sample size, the exact efficacy still needs to be confirmed by higher quality RCT studies.

Acellular allogeneic nerve grafting combined with bone marrow mesenchymal stem cell transplantation for the repair of long-segment sciatic nerve defects:biomechanics and validation of mathematical models

We hypothesized that a chemically extracted acellular allogeneic nerve graft used in combination with bone marrow mesenchymal stem cell transplantation would be an effective treatment for long-segment sciatic nerve defects.To test this,we established rabbit models of 30 mm sciatic nerve defects,and treated them using either an autograft or a chemically decellularized allogeneic nerve graft with or without simultaneous transplantation of bone marrow mesenchymal stem cells.We compared the tensile properties,electrophysiological function and morphology of the damaged nerve in each group.Sciatic nerves repaired by the allogeneic nerve graft combined with stem cell transplantation showed better recovery than those repaired by the acellular allogeneic nerve graft alone,and produced similar results to those observed with the autograft.These findings confirm that a chemically extracted acellular allogeneic nerve graft combined with transplantation of bone marrow mesenchymal stem cells is an effective method of repairing long-segment sciatic nerve defects.

Management of Severe Femoral Bone Defect in Revision Total Hip Arthroplasty-A 236 Hip,6-14-year Follow-up Study

Summary： This study evaluated the clinical effect of impaction bone graft and distal press-fit fixation for the reconstruction of severe femoral bone defect in revision total hip arthroplasty. A total of 234 patients （involving 236 hips） with Paprosky III and 1V femoral bone defects were treated with the revision total hip arthroplasty from June 1998 to Aug. 2006. Impaction bone graft technique was used for 112 hips, with allogeneic freeze-dried bone as bone graft and SP II as prosthesis. With 124 hips, modular distal press-fit fixation and tapered femoral stem （MP stem） were employed. After the operation, the subjects were followed up on regular basis and results were assessed by using the Harris Hip Score （HHS） and 12-item Short Form Health Survey （SF-12）. Radiolucence, subsidence and loosening were observed and complications, including infection, fracture, dislocation etc. were recorded. A 6-14-year follow-up showed that prostheses failed, due to infection, in 4 patients of impaction bone graft group and that 6 patients in the press-fit fixation group experienced prosthesis failure, with the survival rates for the two techniques being 96.43% and 95.16%, respectively. One-way ANOVA showed that prosthesis survival was significantly associated with surgery-related complications （P〈0.05） and was not related to the type of the bone defects （P〉0.05）. The rate of complications bore significant association with the type of bone defects in the two groups （P〈0.05）. Our study showed that the two revision methods could achieve satisfactory mid-term and long-term results for the reconstruction of severe bone defects. It is of great significance for attaining high prosthesis survival rate to select suitable operation on the basis of the type of bone defect. Careful operative manipulation and post-operative rehabilitation aimed at reducing complications are also important.