Investigation of Peri-implant Status and Risk Variables for Implant Failure in Body of Maxilla after Oral Tumor Surgery

The aim of this study was to assess the peri-implant parameters and evaluate the clinical status with the survival of dental implants in body of maxilla after treatments of oral tumor. A follow-up examination included 27 patients who underwent the ablative tumor and （or） reconstructive surgery during a 5-year period. The follow-up protocol included clinical examination, radiological evaluation, and an interview using a standardized questionnaire. The reasons related to implant failure were studied by comparing the amount of failure with the value of marginal bone resorption, probing pocket depth, and plaque index using statistical t-test. The relationship between smoking and implant failure was analyzed statistically by chi-square test. The results showed among the 112 implants observed after implant loading, 29 have failed with the failure rate being 22.14 %. There was no significant correlation between the peri-implant status and the implant failure （P〉0.05）, however, the association of smoking and implant failure was statistically tested （P〈0.05）. It was suggested that the association of peri-implant status and implant failure in the maxilla after tumor surgery can＇t be statistically tested, however smoking was still a mainly significant factor.

Comparative Cytological and Histopathological Study of Peri-Implantitis and Periodontitis

Peri-implant diseases, such as peri-implant mucositis and peri-implantitis, pose significant challenges to the long-term prognosis of dental implants. This study aimed to comprehensively compare peri-implantitis with periodontitis from cytological and histopathological perspectives, shedding light on the morphological characteristics associated with peri-implantitis. Thirteen patients, including six with peri-implantitis and seven with periodontitis, were included in the study. Cytological examination of affected gingival mucosa revealed distinct differences between the two conditions. Peri-implantitis exhibited an inflammatory background predominantly composed of neutrophils with lobulated nuclei, accompanied by stratified squamous epithelial cells showing signs of keratinization. In contrast, periodontitis showed a similar neutrophilic inflammatory background but with non-keratinized epithelial cells. Histopathological examination further confirmed these differences, with peri-implantitis showing keratinized epithelium in the inner epithelial layer. This histological finding aligns with the notion that peri-implantitis has a distinct mucosal profile compared to periodontitis. Additionally, cytological analysis revealed that peri-implantitis had a lower occurrence rate of Light green-positive cells, indicating a tendency toward keratinization. This finding suggests that the presence of keratinized mucosa might be associated with peri-implant health, although further research is needed to clarify this relationship. Overall, this study demonstrates the potential of cytological examination and Papanicolaou staining for assessing mucosal inflammatory conditions and distinguishing between keratinized and non-keratinized cells. These findings underscore the utility of oral mucosal smears as a valuable tool for diagnosing peri-implantitis and enhancing our understanding of its pathogenesis.

Investigation of Bacteria Species Most Involved in Peri-Implantitis

Purpose: Currently, bacteriological examinations of implant treatments target periodontopathic bacteria such as red complex bacteria, including Porphyromonas gingivalis, and detect them qualitatively or quantitatively. However, it seems that those examinations do not reflect the peri-implant tissue conditions precisely, because periodontopathic bacteria are also frequently detected from healthy peri-implant sites. The purpose of the present study was to investigate bacteria species most involved in peri-implantitis using a PCR method. Methods: Polymerase chain reaction (PCR) primers in this study were designed based on partial sequences of 16S rDNA of bacteria species involved in peri-implantitis that were described in numerous previous studies. Peri-implant sulcus fluid (PISF) samples were collected from thirty periodontally healthy patients with implants (HI) and thirty patients with peri-implantitis (PI). Each detection frequency of bacteria species in PISFs of both groups was investigated using a PCR method, and was compared using Fisher’s exact test. Results: In PI group, detection frequencies of Corynebacterium durum, Fretibacterium fastidiosum and Slackia exigua were significantly higher than those of HI group (p P. gingivalis and Tannerella forsythia belonging to red complex were frequently detected in the PISF samples of HI group (p > 0.05). Conclusion: It was suggested that monitoring C. durum and F. fastidiosum levels in PISF samples was useful as a clinical indicator for the evaluation of peri-implant tissue conditions.

Study on matrix metalloproteinase-2, 9 in peri-implant sulcular fluid

Objective: To study the expression of matrix metalloproteinases-2, 9 (MMP-2, MMP-9) of healthy implant and peri-implant sulcular fluid (PISF) by enzyme-linked immunosorbent assay (ELISA) method, and evaluate the level of MMP-2 and MMP-9 in sulcular fluid as an objective indicator of tissue inflammation around implants. Methods: A total of 40 implants were selected from 30 patients who were treated with dental implants and were divided into two groups: the inflammatory group and the healthy control group with 20 pieces respectively. ELISA double antibody sandwich method was used to detect the levels of MMP-2 and MMP-9 in PISF. Results: The MMP-2 and MMP-9 expressions were significantly different between the healthy implant group and the peri-implant group (p < .05). The concentration of MMP-2, MMP-9, and the amount of sulcular fluid in the inflammatory implant group were positively correlated with the clinical parameters (probing depth [PD], modified sulcus bleeding index [mSBI]). Conclusions: Under physiological conditions, the levels of MMP-2 and MMP-9 were low. When the periodontal tissue was stimulated by inflammation, the expression levels of MMP-2 and MMP-9 were increased, which could reflect the severity of inflammation. The increase levels of MMP-2 and MMP-9 in PISF could better reflect the health status of peri-implant tissues, which could be used as an objective indicator to assist in the diagnosis of peri-implant inflammation.

Sustained local delivery of insulin for potential improvement of peri-implant bone formation in diabetes

Dental implantation is an effective standard treatment modality to restore missing teeth and maxillofacial defects. However, in diabetics there is an increased risk for implant failure due to impaired peri-implant osseous healing. Early topical insulin treat- ment was recently shown to normalize diabetic bone healing by rectifying impairments in osteoblastic activities. In this study, insulin/poly(lactic-co-glycolic acid) (PLGA) microspheres were prepared by a double-emulsion solvent evaporation method. Microspheres were then incorporated in fibrin gel to develop a local drug delivery system for diabetic patients requiring im- plant treatment. In vitro release of insulin from fibrin gel loaded with these microspheres was assessed, and sustained prolonged insulin release over 21 days ascertained. To assess the bioactivity of released insulin and determine whether slow release might improve impaired diabetic bone formation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), alkaline phosphatase (ALP) activity, mineralized nodule formation, and ELISA (enzyme-linked immunosorbent assay) assays were performed. The insulin released from the drug delivery system stimulated cell growth in previously inhibited cells, and ameliorated the impaired bone-forming ability of human MG-63 cells under high glucose conditions. Fibrin gel loaded with insulin/PLGA microspheres shows potential for improving peri-implant bone formation in diabetic patients.

Peri-implant femoral fractures:Challenges,outcomes,and proposal of a treatment algorithm

Purpose:Non-prosthetic peri-implant fractures are challenging injuries.Multiple factors must be care-fully evaluated for an adequate therapeutic strategy,such as the state of bone healing,the type of implant,the time and performed personnel of previous surgery,and the stability of fixation.The aim of this study is to propose a rationale for the treatment.Methods:The peri-implant femoral fractures(PIFFs)system,a therapeutic algorithm was developed for the management of all patients presenting a subtype A PIFF,based on the type of the original implant(extra-vs.intra-medulllary),implant length and fracture location.The adequacy and reliability of the proposed algorithm and the fracture healing process were assessed at the last clinical follow-up using the Parker mobility score and radiological assessment,respectively.In addition,all complications were noticed.Continuous variables were expressed as mean and standard deviation,or median and range according to their distribution.Categorical variables were expressed as frequency and percentages.Results:This is a retrospective case series of 33 PIFFs,and the mean post-operative Parker mobility score was(5.60±2.54)points.Five patients(15.1%)achieved complete mobility without aids(9 points)and 1(3.0%)patient was not able to walk.Two other patients(6.1%)were non-ambulatory prior to PPIF.The mean follow-up was(21.51±9.12)months(range 6-48 months).There were 7(21.2%)complications equally distributed between patients managed either with nailing or plating.There were no cases of nonunion or mechanical failure of the original implant.Conclusion:The proposed treatment algorithm shows adequate,reliable and straightforward to assist the orthopaedic trauma surgeon on the difficult decision-making process regarding the management of PIFF occurring in previously healed fractures.In addition,it may become a useful tool to optimize the use of the classification,thus potentially improving the outcomes and minimizing complications.

Platelet-rich plasma for regeneration of neural feedback pathways around dental implants: a concise review and outlook on future possibilities

Along with the development of new materials, advanced medical imaging and surgical techniques, osseointegrated dental implants are considered a successful and constantly evolving treatment modality for the replacement of missing teeth in patients with complete or partial edentulism. The importance of restoring the peripheral neural feedback pathway and thus repairing the lack of periodontal rnechanoreceptors after tooth extraction has been highlighted in the literature. Nevertheless, regenerating the nerve fibers and reconstructing the neural feedback pathways around osseointegrated implants remain a challenge. Recent studies have provided evidence that platelet-rich plasma （PRP） therapy is a promising treatment for musculoskeletal injuries. Because of its high biological safety, convenience and usability, PRP therapy has gradually gained popularity in the clinical field Although much remains to be learned, the growth factors from PRP might play key roles in peripheral nerve repair mechanisms. This review presents known growth factors contributing to the biological efficacy of PRP and illustrates basic and （pre-）clinical evidence regarding the use of PRP and its relevant products in peripheral nerve regeneration. In addition, the potential of local application of PRP for structural and functional recovery of iniured peripheral nerves around dental implants is discussed.

The effect of platform switching on the levels of metal ion release from different implant–abutment couples

The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant-abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy （Ti-6AI-4V） and cobalt-chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups （n = 6）. In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope （SEM） images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups （P〈 0.05）. Titanium was the highest element to be released regardless of abutment size or connection （P〈0.05）. SEM images showed pitting corrosion prominent on the outer borders of the implant and abutment platform surfaces. In conclusion, implant-abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant-abutment couples.

Subtrochanteric fractures after retrograde femoral nailing

Secondary fractures around femoral nails placed for the management of hip fractures are well known. We report, two cases of a fracture of the femur at the interlocking screw site in the subtrochanteric area after retrograde femoral nailing of a femoral shaft fracture. Only a few reports in the existing literature have described these fractures. Two young men after sustaining a fall presented to us with pain, swelling and deformity in the upper thigh region. On enquiring, examining and radiographing them, peri-implant fractures of subtrochanteric nature through the distal interlocking screws were revealed in both patients who also had histories of previous falls for which retrograde intramedullary nailing was performed for their respective femora. Both patients were managed with similar surgical routines including removal of the existing hardware, open reduction and ace cephallomedullary antegrade nailing. The second case did show evidence of delayed healing and was additionally stabilized with cerclage wires. Both patients had uneventful postoperative outcomes and union was evident at the end of 6 mo postoperatively with a good range of motion at the hip and knee. Our report suggests that though seldom reported, peri-implant fractures around the subtrochanteric region can occur and pose a challenge to the treating orthopaedic surgeon. We suggest these be managed, after initial stabilization and resuscitation, by implant removal, open reduction and interlocking intramedullary antegrade nailing. Good results and progression to union can be expected in these patients by adhering to basic principles of osteosynthesis.

Clinical Study on the Relationship between Fixation of Prosthesis and Health of Surrounding Tissues

[Objectives] To explore the effect of mouth outside bonding screw fixation and inside bonding fixation in implanting the prosthesis( crown or bridge) on the health of surrounding tissues,to provide a certain reference for the selection of fixation methods for clinically implanting the prosthesis. [Methods]160 cases of patients needing implanting the prosthesis due to dental arch deficiency were selected. They had excellent alveolar bone. They did not smoke,had no diabetes,and their bone tissue healing was at the early stage. They were randomly divided into A and B groups,80 cases in each group. Group A: the mouth inside and abutment of prosthesis was bonded to a single abutment crown or a single abutment bridge; the bonder on the surface of prosthesis was completely removed and then moved into the implant,and fixed with central retaining screw,this group was called " mouth outside bonding group". Group B: the abutment was located in the implant and fixed using central retaining screw,then the prosthesis( crown or bridge) was bonded to the abutment,the bonder on the surface of prosthesis was removed,and this group was called mouth " mouth inside bonding group". The health condition was compared between two fixing methods for the surrounding tissues of the implant in 24-36 months after restoration. [Results] Group A: the surrounding tissues of the implants for 126 teeth of 80 patients were healthy without occurrence of peripheral inflammation; Group B: in the implants of 112 teeth of 80 patients,7 teeth suffered the peripheral inflammation. Dental implant examination found that there was residue of bonder in the bonding of prosthesis and abutment,3 teeth exfoliated,and 4 teeth were restored after treatment. Through the X2 test,there was significant difference between Group A and Group B( P < 0. 05). [Conclusions] Implant-supported denture often adopts the mouth inside bonding. Since the bonder can not be removed completely,its residue will remain in gingival trough and stimulate the surrounding tissues of the implant and bring about the inflammatory reaction,and even lead to exfoliation of the implant; the mouth inside and abutment of prosthesis was bonded to a single abutment crown or a single abutment bridge,the bonder on the surface of prosthesis was completely removed and then moved into the implant,and fixed with central retaining screw. This method is an effective method for preventing the peripheral inflammation and increasing the success rate of dental implant.

Cuprorivaite/hardystonite/alginate composite hydrogel with thermionic effect for the treatment of periimplant lesion

Peri-implant lesion is a grave condition afflicting numerous individuals with dental implants.It results from persistent periodontal bacteria accumulation causing inflammation around the implant site,which can primarily lead to implant loosening and ultimately the implant loss.Early-stage peri-implant lesions exhibit symptoms akin to gum disease,including swelling,redness and bleeding of the gums surrounding the implant.These signs indicate infection and inflammation of the peri-implant tissues,which may result in bone loss and implant failure.To address this problem,a thermionic strategy was applied by designing a cuprorivaite–hardystonite bioceramic/alginate composite hydrogel with photothermal and Cu/Zn/Si multiple ions releasing property.This innovative approach creates a thermionic effect by the release of bioactive ions(Cu^(2+)and Zn^(2+)and SiO_(3)^(2−))from the composite hydrogel and the mild heat environment though the photothermal effect of the composite hydrogel induced by near-infrared light irradiation.The most distinctive advantage of this thermionic effect is to substantially eliminate periodontal pathogenic bacteria and inhibit inflammation,while simultaneously enhance peri-implant osseointegration.This unique attribute renders the use of this composite hydrogel highly effective in significantly improving the survival rate of implants after intervention in peri-implant lesions,which is a clinical challenge in periodontics.This study reveals application potential of a new biomaterial-based approach for peri-implant lesion,as it not only eliminates the infection and inflammation,but also enhances the osteointegration of the dental implant,which provides theoretical insights and practical guidance to prevent and manage early-stage peri-implant lesion using bioactive functional materials.

Antibacterial activity and mechanism of newly developed Zr-30Ta and Zr-25Ta-5Ti alloys against implant-associated infection

Infection is a common problem after implantation,and the currently used Ti-based implants have insufficient antibacterial activities.The newly developed Zr-30Ta and Zr-25Ta-5Ti alloys exhibited good mechanical properties,low elastic moduli,and high corrosion resistance.In this work,their antibacterial activities and antibacterial mechanisms were investigated.The surface roughness,wettability,and charge of the alloys were evaluated using a profilometer,drop shape analyzer,and electrokinetic analyzer,respectively.The antibacterial activity against Streptococcus mutans and Porphyromonas gingivalis was investigated using the inhibition zone assay,plate count assay,live/dead staining,and scanning electron microscopy(SEM).The reactive oxygen species release(ROS)was evaluated using the 2’7’-dichlorodihydrofluorescein diacetate(DCFH-DA)assay.The results demonstrated that Zr-30Ta and Zr-25Ta-5Ti alloys had favorable smooth,hydrophilic,negatively charged surfaces that decreased bacteria adhesion and prevented biofilm formation.Zr-30Ta and Zr-25Ta-5Ti alloys also exhibited a time-dependent decrease in the bacteria adhesion and viability.Zr-30Ta and Zr-25Ta-5Ti alloys were also found to induce direct membrane damage and increase ROS production,resulting in significantly better antibacterial activities than CP-Ti.Zr-30Ta and Zr-25Ta-5Ti alloys exhibited comparable antibacterial activities.This work suggests that the newly developed Zr-30Ta and Zr-25Ta-5Ti alloys have good antibacterial activity against Streptococcus mutans and Porphyromonas gingivalis and are promising candidate materials for dental and orthopedic implants.

Local bone metabolism balance regulation via double-adhesive hydrogel for fixing orthopedic implants

The effective osteointegration of orthopedic implants is a key factor for the success of orthopedic surgery.However,local metabolic imbalance around implants under osteoporosis condition could jeopardize the fixation effect.Inspired by the bone structure and the composition around implants under osteoporosis condition,alendronate(A)was grafted onto methacryloyl hyaluronic acid(H)by activating the carboxyl group of methacryloyl hyaluronic acid to be bonded to inorganic calcium phosphate on trabecular bone,which is then integrated with aminated bioactive glass(AB)modified by oxidized dextran(O)for further adhesion to organic collagen on the trabecular bone.The hybrid hydrogel could be solidified on cancellous bone in situ under UV irradiation and exhibits dual adhesion to organic collagen and inorganic apatite,promoting osteointegration of orthopedic implants,resulting in firm stabilization of the implants in cancellous bone areas.In vitro,the hydrogel was evidenced to promote osteogenic differentiation of embryonic mouse osteoblast precursor cells(MC3T3-E1)as well as inhibit the receptor activator of nuclear factor-κB ligand(RANKL)-induced osteoclast differentiation of macrophages,leading to the upregulation of osteogenic-related gene and protein expression.In a rat osteoporosis model,the bone-implant contact(BIC)of the hybrid hydrogel group increased by 2.77,which is directly linked to improved mechanical stability of the orthopedic implants.Overall,this organic-inorganic,dual-adhesive hydrogel could be a promising candidate for enhancing the stability of orthopedic implants under osteoporotic conditions.

The overview of antimicrobial peptide-coated implants against oral bacterial infections

Dental implants are the most common therapeutic approach for resolving tooth loss and damage.Despite technical advances in treatment,implant failure rates can be as high as 23%with the major cause of peri-implantitis:a multi-species bacterial infection.With an annual growth rate in implant placements of 8.78%per annum,implant failure caused by bacterial infection is a significant oral and general health issue.The rise in antibiotic resistance in oral bacteria further adds pressure to implant failure;thus,there is a need for adjunctive therapy to improve implant outcomes.Due to the broad spectrum of activity and a low risk of inducing bacterial resistance,peptide antibiotics are emerging as a promising implant coating material to reduce/prevent peri-implantitis and improve dental implant success rates.In this review,we summarised the current strategies of coating antimicrobial peptides(AMPs)onto dental implant material surfaces with multi-functional properties to enhance osteoblast growth and prevent bacterial infections.This review compared the recent reported literature on dental implant coating with AMPs,which will provide an overview of the current dental implant coating strategies using AMPs and insights for future clinical applications.