The biological width around implant

A review of the advances in implant technology: accomplishments and challenges for the design of functionalized surface structures

Biomedical implants are extensively utilized to replace hard-tissue defects owing to their biocompatibility and remarkable tissue-affinity. The materials and functional design are selected based on the resultant osseointegration level and resistance to infection, and these considerations constitute the dominant research topic in this field. However, high rates of implantation failure and peri-implantitis have been reported. Current research on biomedical-implant design encompasses enhancement of the implant surface properties, such as the roughness, nano/micro topography, and hydrophilicity, along with the realization of advanced features including antibacterial properties and cell and immunomodulation regulation. This review considers the two achievements of contemporary implant manufacturing; namely, osseointegration and the realization of antibacterial properties. Present mainstream surface modifications and coatings are discussed, along with functional design technologies and achievements. The impacts of direct surface-treatment techniques and osteogenic functional coatings on osseointegration performance and antibacterial surface structures are elucidated, considering inorganic and organic coatings with antibacterial properties as well as antibiotic-releasing coatings. Furthermore, this review highlights recent advancements in physically driven antimicrobial strategies. Expanding upon existing research, future directions for implant studies are proposed, including the realization of comprehensive functionality that integrates osseointegration and antibacterial properties, as well as patient-specific design. Our study presents a comprehensive review and offers a novel perspective on the design of biomedical implants for enhanced versatility. An in-depth exploration of future research directions will also stimulate subsequent investigations.

A Novel Framework for Optimizing Peri-Implant Soft Tissue in Subcrestally Placed Implants in Single Molar Cases: Integrating Transitional and Subcrestal Zones for Biological Stability

Background/Objectives: The peri-implant soft tissue seal is crucial for the long-term success of subcrestally placed implants (SPIs). However, conventional biologic width-now referred to as supracrestal tissue attachment (STA)-models, originally developed for natural teeth, fail to account for the three-dimensional nature of peri-implant soft tissue adaptation. This study introduces a novel framework integrating the concepts of the transitional zone (TZ) and subcrestal zone (SZ) to systematically optimize peri-implant soft tissue architecture. Methods: A mathematical model was developed to determine the optimal implant placement depth by incorporating the emergence angle (EA), soft tissue thickness (STT), and peripheral crestal offset (PCO). Additionally, a three-dimensional peri-implant soft tissue analysis (3DSTA) approach utilizing cone beam computed tomography (CBCT) imaging was implemented to evaluate peri-implant soft tissue adaptation and emergence profile design. Clinical parameters were analyzed to establish guidelines for optimizing SPI placement depth and peri-implant soft tissue stability. Results: This study introduces the concept of self-sustained soft tissue (SSST), a biologically functional structure composed of the TZ and SZ, which enhances peri-implant health and stability. The proposed framework provides clinical guidelines for optimizing SPI placement depth, emergence profile contouring, and peri-implant soft tissue thickness to mitigate the risk of peri-implant mucositis. By shifting from a traditional two-dimensional perspective to a multidimensional analysis, this approach offers an evidence-based foundation for achieving biologically stable and esthetically predictable outcomes. Conclusions: The proposed three-dimensional model advances the understanding of peri-implant soft tissue adaptation by integrating novel anatomical and biomechanical concepts. By redefining peri-implant biologic width through the introduction of TZ and SZ, this study provides a structured framework for optimizing SPI placement and soft tissue management. Future research should focus on validating this model through histological studies and long-term clinical trials to refine its application in clinical practice.

Bioactive materials from berberine-treated human bone marrow mesenchymal stem cells accelerate tooth extraction socket healing through the jaw vascular unit

Delayed tooth extraction socket (TES) healing can cause failure of subsequent oral implantation and increase socioeconomic burden on patients. Excessive amounts of M1 macrophages, apoptotic neutrophils (ANs), and neutrophil extracellular traps (NETs) impair alveolar bone regeneration during TES healing. In the present study, we first discovered that conditioned medium (CM) collected from berberine-treated human bone marrow mesenchymal stem cells (BBR-HB-CM) accelerated TES healing. BBR-HB-CM contained bioactive materials that promoted the polarization of macrophages from M1 to M2, impeded the formation of ANs and NETs, and modulated M2 macrophage efferocytosis in vivo and in vitro. Mechanistically, BBR-HB-CM promoted bone formation by inhibiting macrophage-myofibroblast transition and reprogrammed macrophage polarization through p85/AKT/mTOR pathway-dependent autophagy. The 3-methyladenine abolished the therapeutic effects of BBR-HB-CM. Further studies revealed that BBR-HB-CM accelerated TES healing in rats with type 2 diabetes mellitus. Overall, our results demonstrated that BBR-HB-CM had high potential to promote rapid TES healing.

Histological Analysis of Biological Width and Collagen Fibers Orientation Around Screw-Less, Morse Taper, Hemispherical Base Abutments 8 and 16 Weeks After Implant Uncovering: An Observational Clinical Trial

Objectives: This study aimed to histologically evaluate, in humans, the orientation of collagen fibers around screw-less, Morse taper, hemispherical base abutments. Methods: This study was designed as an observational, case-control, clinical trial to evaluate the histological orientation of collagen fibers around implants. Biopsies of the peri-implant tissue were performed 8 (group A, control) or 16 (group B, test) weeks of implant uncovering, and histologically analyzed under optical microscope using Hematoxylin and Eosin, Masson, and Picro Sirius histochemical staining and a scanning electron microscope. Results: Eight patients were enrolled in this study and 16 biopsies were performed. All the biopsies were correctly analyzed. The histological examination of cross-sectional portions of the tissue taken 8 weeks after implant uncovering showed the almost complete absence of epithelial lining, while the connective tissue bundles in the superficial portion showed a lower circular pattern. The histochemical cross-section examination of the tissue taken 16 weeks after implant uncovering showed the partial presence of non-keratinizing epithelial lining at the implant site and the collagen bundles showed a greater organization, with a circumferential course around the abutment. At 8 weeks, the final histological analysis showed an average height of 1.01 mm for the keratinized epithelium, 0.83 mm for the non-keratinized epithelium, and 1.39 mm for the connective tissue. While, at 16 weeks, the values were 1.20 mm, 0.48 mm, and 1.11 mm, respectively. No statistically significant differences were found between the groups (p > 0.05). Conclusions: Histologically, there were not any differences in the height and profile of the gingiva between 8 and 16 weeks of healing after prosthesis delivery. Greater organization of the collagen fibers with a circumferential course around the abutment was found in the test group (16 weeks) compared with the control group (8 weeks).

Two Severely Compromised Teeth Restored Using Digital Planning Combined With Double Orthodontic Magnetic Extrusion: A Case Report

Tooth tissue loss due to dental caries is frequently challenging to restore, and this loss is made worse by proximal tooth borders that extend below the gingival margin. This report describes a digitally designed case in which the ferrule and supracrestal tissue attachment were preserved by simultaneous double magnetic extrusion of two root filled teeth. A 67-year-old male presented with the chief concern of a fractured maxillary left canine. The maxillary left lateral incisor and canine underwent rapid magnetic extrusion to create ferrules (3 mm). Eighteen months after treatment, the restorative margins were sound and the teeth with associated periodontal tissues were healthy. The positive results demonstrate that the combination of digital planning and double magnetic extrusion has potential as a technique for restoring severely damaged teeth where insufficient supra-gingival tooth tissue remains. Adjacent root canal treated teeth with severe loss of coronal structure are suitable candidates for double magnetic extrusion.

Evaluating the microgap and sealing capability in four implant systems with different interlockings under different tightening torques: an in-vitro study

PURPOSE

This study assessed the microgap width and adhesion of three bacterial species in four dental implants with different interlocks under four screwing torques.

MATERIALS AND METHODS

Ten samples of four implant systems with various interlockings, including full-hexagonal (FHI), cylindrical-conical trilobe-index (TLI), Morse-taper with octagon terminal index (OI), and hexagonal interlock (slip-fit) (HI-SF), were used. The abutments were screwed to the fixtures under torques of 10, 20, 30, and 40 Ncm. The microgap between the abutment and the platform was assessed using a Scanning Electron Microscope (SEM). The leakage of 3 bacteria, including Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, was evaluated under 30 Ncm torque.

RESULTS

The TLI system showed the widest gap under all torques compared to others. There was no significance among all systems under different screwing torques. Regarding the leakage, there was no adherence to E. coli and S. aureus and 36.4% of Ps. aeruginosa to the HI-SF, followed by the OI system. The FHI and TLI systems showed the highest bacterial adherence.

CONCLUSION

Even with low torque, the studied systems showed gap widths narrower than acceptable width. Implant systems with FHI and OI demonstrated misfits of less than 2 µm upon 10 Ncm and less than 1 µm when the torque increases, giving them priority to be used in areas with poor bone quality. The HI-SF demonstrated a high ability to resist the adherence to E. coli and S. aureus, followed by OI. However, Ps. aeruginosa demonstrated a high ability to adhere to all systems.

Surface modification strategies to reinforce the soft tissue seal at transmucosal region of dental implants

Soft tissue seal around the transmucosal region of dental implants is crucial for shielding oral bacterial invasion and guaranteeing the long-term functioning of implants. Compared with the robust periodontal tissue barrier around a natural tooth, the peri-implant mucosa presents a lower bonding efficiency to the transmucosal region of dental implants, due to physiological structural differences. As such, the weaker soft tissue seal around the transmucosal region can be easily broken by oral pathogens, which may stimulate serious inflammatory responses and lead to the development of peri-implant mucositis. Without timely treatment, the curable peri-implant mucositis would evolve into irreversible peri-implantitis, finally causing the failure of implantation. Herein, this review has summarized current surface modification strategies for the transmucosal region of dental implants with improved soft tissue bonding capacities (e.g., improving surface wettability, fabricating micro/nano topographies, altering the surface chemical composition and constructing bioactive coatings). Furthermore, the surfaces with advanced soft tissue bonding abilities can be incorporated with antibacterial properties to prevent infections, and/or with immunomodulatory designs to facilitate the establishment of soft tissue seal. Finally, we proposed future research orientations for developing multifunctional surfaces, thus establishing a firm soft tissue seal at the transmucosal region and achieving the long-term predictability of dental implants.

Role of immune dysregulation in peri-implantitis

Peri-implantitis, a complex condition that can lead to dental implant failure, is characterized by inflammatory destruction resulting from immune dysregulation. Oral microbial dysbiosis and foreign body stimulation are the main factors contributing to such dysregulation, impairing immune cell function and triggering an inflammatory response. Immune dysregulation plays a critical role in the pathophysiology of peri-implantitis, impacting the balance of T cell subsets, the production of inflammatory factors, and immune-related molecular signaling pathways. Understanding the relationship between immune dysregulation and peri-implantitis is crucial for developing targeted strategies for clinical diagnosis and individualized treatment planning. This review explores the similarities and differences in the immune microenvironment of oral bacterial infections and foreign body rejection, analyzes the relevant molecular signaling pathways, and identifies new key targets for developing innovative immunotherapeutic drugs and effective and personalized treatment modalities for peri-implantitis. Additionally, it addresses the challenges and potential directions for translating immunotherapy into clinical practice for peri-implantitis, offering insights that bridge the gaps in current literature and pave the way for future research.

The research status and future direction of polyetheretherketone in dental implant -A comprehensive review

Currently, dental implants primarily rely on the use of titanium and titanium alloys. However, the extensive utilization of these materials in clinical practice has unveiled various problems including stress shielding, corrosion, allergic reactions, cytotoxicity, and image artifacts. As a result, polyetheretherketone (PEEK) has emerged as a notable alternative due to its favorable mechanical properties, corrosion resistance, wear resistance, biocompatibility, radiation penetrability and MRI compatibility. Meanwhile, the advancement and extensive application of 3D printing technology has expanded the range of medical applications for PEEK, including artificial spines, skulls, ribs, shinbones, hip joints, and temporomandibular joints. In this review, we aim to assess the advantages and disadvantages of PEEK as a dental implant material, summarize the measures taken to address its shortcomings and their effects, and provide insight into the future potential of PEEK in dental implant applications, with the goal of offering guidance and reference for future research endeavors.

Silk fibroin microgrooved zirconia surfaces improve connective tissue sealing through mediating glycolysis of fibroblasts

The use of zirconia has significantly enhanced the aesthetic outcomes of implant restorations. However, peri-implantitis remains a challenge to long-term functionality of implants. Unlike the perpendicularly arranged collagen fibers in periodontal tissue, those in peri-implant tissue lie parallel to the abutment surface and contain fewer fibroblasts, making them more prone to inflammation. Studies have shown that microgroove structures on implant abutments could improve surrounding soft tissue structure. However, creating precise microgrooves on zirconia without compromising its mechanical integrity is technically challenging. In this study, we applied inkjet printing, an additive manufacturing technique, to create stable silk fibroin microgroove (SFMG) coatings of various dimensions on zirconia substrates. SFMG significantly improved the hydrophilicity of zirconia and showed good physical and chemical stability. The SFMG with 90 μm interval and 10 μm depth was optimal in promoting the proliferation, alignment, and extracellular matrix production of human gingival fibroblasts (HGFs). Moreover, the in vitro results revealed that SFMG stimulated key glycolytic enzyme gene expression in HGFs via the PI3K-AKT-mTOR pathway. Additionally, the in vivo results of histological staining of peri-abutments soft tissue showed that SFMG promoted the vertical alignment of collagen fibers relative to the abutment surface, improving connective tissue sealing around the zirconia abutment. Our results indicated that SFMG on zirconia can enhance HGF proliferation, migration and collagen synthesis by regulating glycolysis though PI3K-AKT-mTor pathway, thereby improving connective tissue sealing.

Clinical and biochemical assessment of the soft tissue response to titanium stock versus custom composite resin healing abutments

STATEMENT OF PROBLEM

Custom healing abutments made of flowable composite resin have gained popularity, although the soft tissue response to composite resin has not been adequately studied.

PURPOSE

The purpose of this randomized controlled clinical trial was to evaluate the soft tissue response to titanium stock healing abutments and custom composite resin healing abutments by assessing clinical indices and the level of matrix metalloproteinase-8 (MMP-8) in the peri-implant crevicular fluid (PICF).

MATERIAL AND METHODS

A randomized controlled clinical trial was performed on 42 osseointegrated implants. The implants were divided into 2 groups: a test group comprising 21 custom composite resin healing abutments that were attached to the implants at second stage surgery and a control group comprising 21 stock titanium healing abutments. Plaque index (PL), bleeding on probing (BOP), modified gingival index (MGI), and level of MMP8 were measured at the second and fourth week after second stage surgery. Peri-implant crevicular fluid was collected by paper points at each follow-up, and the level of MMP8 was measured by an enzyme-linked immunosorbent assay kit. For statistical analysis, group comparisons used the Mann-Whitney U test, and comparisons within each group at 2 and 4 weeks used the Wilcoxon Sign Rank test. Group differences were analyzed with the Fisher exact test, and the McNemar test was used to compare percentages at 2 and 4 weeks. All tests were two-tailed (α=.05).

RESULTS

For the PI, no statistically significant differences were found within groups or between groups (P>.05). Bleeding on probing was positive in 14.3% of titanium abutments versus 20% of composite resin abutments at 4 weeks, with no significant difference between groups (P>.05). Similarly, the mean MGI was 0.38 ±0.5 in the control group while it was 0.4 ±0.5 in the test group, with no significant differences between groups (P>.05). The MMP8 level at 2 weeks was 11.1 ±8.65 and 13.11 ±9.29 for the control and test groups, respectively while it was 16.35 ±8.31 and 19.80 ±8.44 at 4 weeks, showing a statistically significant increase within groups (P<.05). No significant difference between groups was detected at either follow-up time point regarding MMP8 level (P>.05).

CONCLUSIONS

The clinical and biochemical soft tissue response to composite resin healing abutments and titanium stock healing abutments were comparable, suggesting the clinical safety of custom composite resin healing abutments.

Novel digital technique for measuring the volumetric healing process of free gingival grafts surrounding dental implants

The objective of the present study was to analyze and describe a new digital technique for analyzing the volumetric healing process of free gingival grafts in both donor and recipient locations surrounding a dental implant, as well as to compare the reliability of conventional and digital techniques for measuring the width of the free gingival graft in the recipient location throughout the healing process.

Materials and methods

Ten patients presenting with mucositis linked to a dental implant were included. A preoperative soft tissue width <2 mm, with probing pocket depth <5 mm, edema and inflammation and bleeding on probing was determined A digital impression was taken of both donor and recipient locations using an intraoral scan, generating a Standard Tessellation Language digital file both preoperatively (STL1) and after 1 week (STL2), 1 month (STL3), 3 months (STL4), and 6 months (STL5) of follow-up. Afterwards, the digital files (STL1-STL5) were aligned using a reverse engineering morphometric software, and Student's t-test was used to analyze changes in volume at the donor and recipient locations. Additionally, widths were measured both clinically and digitally so as to compare the reliability of these measurement techniques. The repeatability and reproducibility of both these measurement techniques were also analyzed using Gage R&R statistical analysis.

Results

Gage R&R found that the total variability of the digital technique was 0.6% (among the measures of each operator) and 7.6% (among operators); as variability was under 10%, the results were repeatable and reproducible. In addition, there were statistically significant differences between donor and recipient locations in healing process volume (mm3) after one week (p = 0.0110), one month (p = 0.0007), three months (p < 0.0001) and six months (p = 0.0004) of follow-up.

Conclusion

The digital measurement technique provided accurate, repeatable, and reproducible results when analyzing the volumetric and linear measures of the healing process in both the donor and recipient locations of a free gingival graft surrounding a dental implant, with significantly higher tissue volume in the recipient location.

Digital workflow for definitive immediately loaded complete arch CAD-CAM implant-supported prosthesis in 3 appointments without using intraoral scanning

This article presents a rapid technique for the accurate transfer of implant positions immediately after image-guided surgery to enable the immediate installation of a definitive complete arch implant-supported prosthesis with an implant biological width of 3 mm within 3 appointments. A sleeveless copy of the implant surgical guide is magnetically connected to a reference guide to ensure the accurate capture of cylindrical titanium transfer abutments. In the laboratory, the sleeveless guide with the splinted transfer abutments attached is used to generate a definitive cast to be scanned with a desktop scanner. The resulting digital definitive cast is then combined with the original meshes of the prosthetically driven virtual treatment plan to enable a definitive computer-aided design and computer-aided manufactured prosthesis to be fabricated and installed with passive fit.

Restoration of Teeth with Severely Compromised Tooth Structure using Digital Planning Combined with Orthodontic Magnetic Extrusion-A Report of 2 Cases

This report outlines 2 digitally planned cases in which the teeth underwent magnetic extrusion to preserve the supracrestal tissue attachment and regain the ferrule, followed by their restoration. Case 1: A 42-year-old man with the chief concern of a fractured right maxillary second premolar. Following the completion of root canal treatment, the remaining tooth structure was insufficient to create a ferrule for tooth restoration. For this scenario, a rapid magnetic extrusion technique was performed on tooth #4 to obtain an approximate 3-mm ferrule. The condition of both the dentition and the restorative margin was acceptable 18 months following treatment. Case 2: A 62-year-old man with the chief complaint of mobility on both sides of the maxillary arch in relation to a tooth-supported fixed partial denture (FPD). Following removal of the FPD, multiple extractions were carried out and tooth #6 was subjected to magnetic extrusion in 3 stages to a maximum of 4 mm to obtain a ferrule. At the 18-month and 3-year follow-up appointments, the tooth had no symptoms and the gingiva around the restorations had optimal architecture and margins. The 3-dimensional digital planning was helpful in precisely positioning the magnets within the tooth and the provisional restorations to facilitate axial extrusion. The extruded teeth were restored with zirconia crowns in both cases. The beneficial outcomes observed from these cases provides evidence that the integration of digital planning and magnetic extrusion holds promise as a method for reconstructing teeth with crowns that are significantly compromised.

An Injectable Black Phosphorus Hydrogel for Rapid Tooth Extraction Socket Healing

The excess production of reactive oxygen species (ROS) will delay tooth extraction socket (TES) healing. In this study, we developed an injectable thermosensitive hydrogel (NBP@BP@CS) used to treat TES healing. The hydrogel formulation incorporated black phosphorus (BP) nanoflakes, recognized for their accelerated alveolar bone regeneration and ROS-scavenging properties, and dl-3-n-butylphthalide (NBP), a vasodilator aimed at enhancing angiogenesis. In vivo investigations strongly demonstrated that NBP@BP@CS improved TES healing due to antioxidation and promotion of alveolar bone regeneration by BP nanoflakes. The sustained release of NBP from the hydrogel promoted neovascularization and vascular remodeling. Our results demonstrated that the designed thermosensitive hydrogel provided great opportunity not only for ROS elimination but also for the promotion of osteogenesis and angiogenesis, reflecting the "three birds with one stone" concept, and has tremendous potential for rapid TES healing.

Long-Term Clinical Outcomes of 3D-Printed Subperiosteal Titanium Implants: A 6-Year Follow-Up

As an alternative to regenerative therapies, numerous authors have recently proposed bringing back subperiosteal implants. The aim of the study was to present our clinical experience with a subperiosteal jaw implant that needs minimal bone preparation and enables the rapid implantation of prosthetic teeth in edentulous, atrophic alveolar bone. The research included 36 complete or partial edentulous patients (61 subperiostal implants) over a period of 6 years. To create the patient-specific subperiostal implants design, DentalCAD 3.0 Galway software (exocad GmbH, Darmstadt, Germany) was used and fabricated with a Mysint 100 (Sisma S.p.A., Piovene Rocchette, Italy) by titanium alloy powder. The results showed that only 9 of the 36 cases were successful at 6-year follow-up, while 27 cases had complications, including exposure of the metal frame (early or delayed), mobility of the device prior to the first 4-6 months, and late mobility due to recurrent infections and progressive structure exposure; 1 case failed for reasons unrelated to the device. This study indicated that the prudent application of fully customized subperiosteal jaw implants is a dependable alternative for the dental rehabilitation of atrophic edentulous cases that necessitate bone grafts for traditional fixed dental implant solutions.

Clinical outcomes and risk factor analysis of dental implants inserted with lateral maxillary sinus floor augmentation: A 3- to 8-year retrospective study

AIM

To evaluate the 3- to 8-year outcomes of dental implants placed with lateral sinus floor augmentation (LSFA) and to identify factors affecting implant survival.

MATERIALS AND METHODS

This retrospective study was performed by screening all implants placed with LSFA procedures, which were conducted between January 2012 and December 2016. Subantral bone gain (SABG) and apical bone height (ABH) were assessed using panoramic radiographs. The cumulative survival rate of implants was analysed using life-table analysis and Kaplan-Meier survival curves. The influential risk factors affecting survival were assessed using univariate log-rank tests and multivariable mixture cure rate model. Implant complications were recorded.

RESULTS

Based on the established criteria, a total of 449 patients (760 implants) were included in this study. In the 3- to 8-year follow-up (mean ± SD, 5.81 ± 1.33 years), 15 implants in 14 patients failed, with a CRS of 96.81% on an implant basis and 95.07% on a patient basis. A history of periodontitis and poor compliance with supportive periodontal treatment was associated with a significantly higher risk of implant failure at both implant and patient levels. Significant decreases in ABH occurred during each yearly interval except for 3 years. A similar trend has been observed for SABG at 1, 2, 6 and 8 years. The total complication rate was 31.84% on implant basis, with peri-implant mucositis (21.58%) being the most frequent biologic complication and porcelain cracking (5.00%) being the most common technical complication.

CONCLUSIONS

Implant with LSFA is a reliable treatment option in atrophic maxilla. A history of periodontitis without regular supportive periodontal treatment was identified as a predictor for implant failure. Slight but significant shrinkage of vertically augmented bone can be observed after implant placement.

Bioactive materials from berberine-treated human bone marrow mesenchymal stem cells promote alveolar bone regeneration by regulating macrophage polarization

Alveolar bone regeneration has been strongly linked to macrophage polarization. M1 macrophages aggravate alveolar bone loss, whereas M2 macrophages reverse this process. Berberine (BBR), a natural alkaloid isolated and refined from Chinese medicinal plants, has shown therapeutic effects in treating metabolic disorders. In this study, we first discovered that culture supernatant (CS) collected from BBR-treated human bone marrow mesenchymal stem cells (HBMSCs) ameliorated periodontal alveolar bone loss. CS from the BBR-treated HBMSCs contained bioactive materials that suppressed the M1 polarization and induced the M2 polarization of macrophages in vivo and in vitro. To clarify the underlying mechanism, the bioactive materials were applied to different animal models. We discovered macrophage colony-stimulating factor (M-CSF), which regulates macrophage polarization and promotes bone formation, a key macromolecule in the CS. Injection of pure M-CSF attenuated experimental periodontal alveolar bone loss in rats. Colony-stimulating factor 1 receptor (CSF1R) inhibitor or anti-human M-CSF (M-CSF neutralizing antibody, Nab) abolished the therapeutic effects of the CS of BBR-treated HBMSCs. Moreover, AKT phosphorylation in macrophages was activated by the CS, and the AKT activator reversed the negative effect of the CSF1R inhibitor or Nab. These results suggest that the CS of BBR-treated HBMSCs modulates macrophage polarization via the M-CSF/AKT axis. Further studies also showed that CS of BBR-treated HBMSCs accelerated bone formation and M2 polarization in rat teeth extraction sockets. Overall, our findings established an essential role of BBR-treated HBMSCs CS and this might be the first report to show that the products of BBR-treated HBMSCs have active effects on alveolar bone regeneration.

[The results of increasing the thickness of soft tissues after using collagen matrices and connective tissue grafts]

THE STUDY AIMS

To evaluate and compare the growth of gingiva around dental implants following the use of collagen matrices and connective tissue grafts (CTG).

MATERIALS AND METHODS

The study included 80 study participants, who were divided into four groups based on the type of material used to enhance gingival thickness. Two groups utilized collagen matrices, Fibro-Gide and FibroMatrix as materials, while the other two groups utilized CTG obtained from the hard palate or tubercle area of the maxilla as controls. Measurements of gum tissue thickness were obtained before surgery and three- and six-months following surgery using three different methods: mucosa piercing with a spreader and ruler, digital impression, and comparison of cone-beam computed tomography (CBCT) scans and digital impressions.

RESULTS

At six-months examination after the use of grafts from the palate and tubercle, there was a significantly greater increase in gum tissue thickness compared to the use of collagen matrices. The increase was 1.6±0.3 mm and 1.7±0.6 mm for palatal and tubercle grafts, correspondingly, compared to 1.3±0.4 mm for Fibro-Gide and 0.9±0.5 mm for FibroMatrix.

CONCLUSION

To increase the thickness of soft tissue it is recommended to use CTG from the tubercle or palate. If there is a lack of available donor areas, collagen matrices may be used as a substitute.

Comparative evaluation of gingival fibroblast growth on 3D-printed and milled zirconia: An in vitro study

PURPOSE

The purpose of this study was to analyze the fibroblast growth and proliferation on 3D-printed zirconia in presence and absence of porosities.

MATERIAL AND METHODS

A total of 40 bars (8 × 4 × 3) were included in this study. Thirty 3D-printed and 10 milled zirconia samples were prepared. The 3D-printed samples had different porosities, 0% (PZ0), 20% (PZ20), and 40% (PZ40) with 10 specimens in each group. Milled zirconia samples were used as the control (MZ). Rat gingival fibroblasts were cultured for 48 h, and the proliferation of fibroblasts on each sample in each group (n = 10) was determined by MTT assays. The differences among the four groups were compared by one-way ANOVA. To test the significance of the observed differences between two groups, an unpaired Student's t-test was applied. The significance level was set at p < 0.05. Qualitative analysis for the cell culture was performed using scanning electron microscopy.

RESULTS

One-way ANOVA showed that the numbers of the fibroblasts among the four groups had a statistical difference. Post hoc Bonferroni test revealed that there was no significant difference between PZ0 and MZ; however, all other groups and among groups were significantly different.

CONCLUSIONS

Fibroblasts had a better affinity toward the MZ and PZ0 in a short period of cell culture time.

Effect of different implant locations and abutment types on stress and strain distribution under non-axial loading: A 3-dimensional finite element analysis

Background/purpose

Dental implants have been a popular treatment for replacing missing teeth. The purpose of this study was to investigate the impact of engaging (hexagonal) and non-engaging (non-hexagonal) abutments in various six-unit fixed prosthesis on the stress distribution and loading located in the implant neck, implant abutment, and surrounding bone.

Materials and methods

Three implants were digitally designed and inserted parallel to each other in edentulous sites of the maxillary right canine, maxillary right central incisor, and maxillary left canine. Titanium base engaging abutments, non-engaging abutments and connecting screws were designed. Five distinct models of 6-unit fixed dental prosthesis were created, each featuring different combinations of various abutments. Forces (45-degree angle) were applied to the prosthesis, allowing for the analysis of the stress distribution on the implant neck and abutments, and the maximum and minimum principal stress values on the cortical and trabecular bone.

Results

Von Mises stress values and stress distributions located in the implant neck region due to the applied loading forces were analyzed. The overall stress values were highest while employing the hexagonal abutments. The maxillary left canine with a hexagonal abutment (model 5) reported the highest von mises value (64.71 MPa) while the maxillary right canine with a non-hexagonal abutment (model 4) presented lowest von mises value (56.69 MPa).

Conclusion

The results suggest that both the various abutment combinations (engaging and non-engaging) on five different models have a similar influence on the distribution of stress within the implant system.

Histatin 1-modified SIS hydrogels enhance the sealing of peri-implant mucosa to prevent peri-implantitis

Dental implants make it possible to replace teeth in more sophisticated ways. Nevertheless, peri-implantitis is one of the leading causes of implant failure, which can be avoided with proper soft tissue sealing. The aim of this study was to achieve the promotion of the synthesis of peri-implant epithelial hemidesmosome through Histatin 1 and porcine small intestinal submucosa (SIS) hydrogel to form a good peri-implant seal. The results show that hydrogel can improve the biological barrier function around implants by combining antibacterial, promoting soft tissue healing and promoting epithelial bonding. This means that the morphology and anti-infection ability of soft tissue are enhanced, which ensures the long-term stability of the implant.SIS-Hst1 hydrogel has certain clinical application in the prevention and early treatment of peri-implantitis. In conclusion, Hst1-SIS hydrogel, as a local administration system, provides experimental evidence for the prevention of peri-implant disease.

The Role of Caspase-11 and Pyroptosis in the Regulation of Inflammation in Peri-Implantitis

Peri-implantitis is an important cause of oral implant failure. In the past, TLR4 and TLR2 in the Toll-like family were generally considered as the key immune recognition receptors regulating peri-implantitis. However, under the guidance of this theory, there are still some unexplainable peri-implantitis symptoms. With the discovery of novel intracellular LPS receptor Caspase-11, a new understanding of inflammatory signaling and immune regulation in the development of peri-implantitis has been gained. However, the regulatory role of Caspase-11 in peri-implantitis and its crosstalk with the TLR4 pathway remain unclear. The therapeutic effect of drugs targeting Caspase-11 on peri-implantitis is still in its early stages. In view of this situation, this paper reviews the possible role of Caspase-11 in peri-implant inflammation, elaborated the entry process of LPS and the activation mechanism of Caspase-11, and analyzes the differences in Caspase-11 between commonly studied animals, mice and humans. The current research hotspots and challenges are also analyzed to provide new insights and ideas for researchers.

Clinical and radiographic results of crestal vs. subcrestal placement of implants in posterior areas: A split-mouth randomized controlled clinical trial

OBJECTIVE

The objective of this study was to evaluate the peri-implant soft tissue and marginal bone loss (MBL) around implants with platform-switching and internal conical connection placed at crestal and subcrestal levels in posterior areas.

MATERIALS AND METHODS

Nineteen partially edentulous patients with at least two adjacent missing teeth in posterior areas unilaterally or bilaterally were included. Forty-two implants were placed randomly at the crestal or subcrestal (1 mm) level in a split-mouth design. Implant-supported fixed dental prostheses with screw retention were delivered after 4 months of healing. Clinical and radiological measurements were performed at implant placement (T0), restoration delivery (T1), and 1-year follow-up after loading (T2). MBL was calculated as the change in distance from the implant-abutment interface to the first radiographically visible bone-implant contact. A repeated-measures mixed ANOVA followed by a paired Student's t-test with the Bonferroni correction was used for statistical analysis. p < 0.05 was considered statistically significant.

RESULTS

Eighteen patients with thirty-eight implants completed the study at T2. The MBL was lower in the subcrestal group than in the crestal group (0.04 ± 0.08 vs. 0.17 ± 0.17 mm, p = 0.004). The peri-implant probing depth (PD) was 2.31 ± 0.48 mm in the subcrestal group and 1.92 ± 0.43 mm in the crestal group; this difference was statistically significant (p = 0.002). Intragroup comparison showed no significant differences in MBL, or PD around the crestal group and subcrestal group from T1 to T2.

CONCLUSION

After 1 year of functional loading, subcrestal placement of implants with platform-switching and internal conical connection showed lower MBL and was associated with greater PD and peri-implant soft tissue height than implants placed at the crestal level.

Impact on peri-implant connective tissue of laser treated versus traditional healing abutments: a human clinical trials

BACKGROUND

Dental implant is the principal treatment for edentulism and the healthiness of the peri-implant tissue has a pivotal role for its longterm success. In addition, it has been shown that also the topography of the healing abutment can influence the outcome of the restoration. The objective of this human clinical trial was to assess the impact of a novel laser-treated healing abutment on peri-implant connective tissue and extracellular matrix proteins compared to the conventional machined surface, which served as the control group.

METHODS

During second surgical stage a customized healing abutment were inserted on 30 single dental implants. Healing abutments were realized with two alternated different surface (two side laser-treated surfaces and two side machined surfaces) in order to be considered both as test and control on the same implant and reduce positioning bias. Following the soft tissue healing period (30 ± 7 days) a 5 mm circular biopsy was retrieved. Immuno-histochemical and quantitative real-time PCR (qPCR) analyses were performed on Collagen, Tenascin C, Fibrillin I, Metalloproteinases (MMPs) and their inhibitor (TIMPs). 15 were processed for qPCR, while the other 15 were processed for immunohistochemical analysis. Paired t-test between the two groups were performed. A value of p < 0.05 was considered statistically significant.

RESULTS

Results revealed that the connective tissue facing the laser-treated surface expressed statistically significant lower amount of MMPs (p < 0.05) and higher level of TIMPs 3 (p < 0.05), compared to the tissue surrounding the machined implant, which, in turn expressed also altered level of extracellular matrix protein (Tenascin C, Fibrillin I (p < 0.05)) and Collagen V, that are known to be altered also in peri-implantitis.

CONCLUSIONS

In conclusion, the laser-treated surface holds promise in positively influencing wound healing of peri-implant connective tissue. Results demonstrated that topographic nature of the healing abutments can positively influence mucosal wound healing and molecular expression. Previous studies have been demonstrated how laser treatment can rightly influence integrity and functionality of the gingiva epithelium and cell adhesion. Regarding connective tissue different molecular expression demonstrated a different inflammatory pattern between laser treated or machined surfaces where laser treated showed better response. Targeted interventions and preventive measures on peri- implant topography could effectively minimize the risk of peri-implant diseases contributing to the long-term success and durability of restoration. However, new studies are mandatory to better understand this phenomenon and the role of this surface in the peri-implantitis process.  TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov Identifier: (Registration Number: NCT05754970 ). Registered 06/03/2023, retrospectively registered.

Marginal Bone Level and Biomechanical Behavior of Titanium-Indexed Abutment Base of Conical Connection Used for Single Ceramic Crowns on Morse-Taper Implant: A Clinical Retrospective Study

The goal of this retrospective clinical study was to evaluate the behavior of Morse-taper indexed abutments by analyzing the marginal bone level (MBL) after at least 12 months of function. Patients rehabilitated with single ceramic crowns between May 2015 and December 2020 received single Morse-taper connection implants (DuoCone implant) with two-piece straight abutment baseT used for at least 12 months, presenting periapical radiograph immediately after crown installation were enrolled. The position of the rehabilitated tooth and arch (maxilla or mandible), crown installation period, implant dimensions, abutment transmucosal height, installation site (immediate implant placement or healed area), associated with bone regeneration, immediate provisionalization, and complications after installation of the final crown were analyzed. The initial and final MBL was evaluated by comparing the initial and final X-rays. The level of significance was α = 0.05. Seventy-five patients (49 women and 26 men) enrolled had a mean period of evaluation of 22.7 ± 6.2 months. Thirty-one implant-abutment (IA) sets had between 12–18 months, 34 between 19–24 months, and 44 between 25–33 months. Only one patient failed due to an abutment fracture after 25 months of function. Fifty-eight implants were placed in the maxilla (53.2%) and 51 in the mandible (46.8%). Seventy-four implants were installed in healed sites (67.9%), and 35 were in fresh socket sites (32.1%). Thirty-two out of these 35 implants placed in fresh sockets had the gap filled with bone graft particles. Twenty-six implants received immediate provisionalization. The average MBL was −0.67 ± 0.65 mm in mesial and −0.70 ± 0.63 mm in distal (p = 0.5072). The most important finding was the statistically significant difference comparing the values obtained for MBL between the abutments with different transmucosal height portions, which were better for abutments with heights greater than 2.5 mm. Regarding the abutments’ diameter, 58 had 3.5 mm (53.2%) and 51 had 4.5 mm (46.8%). There was no statistical difference between them, with the following means and standard deviation, respectively, −0.57 ± 0.53 mm (mesial) and −0.66 ± 0.50 mm (distal), and −0.78 ± 0.75 mm (mesial) and −0.746 ± 0.76 mm (distal). Regarding the implant dimensions, 24 implants were 3.5 mm (22%), and 85 implants (78%) had 4.0 mm. In length, 51 implants had 9 mm (46.8%), 25 had 11 mm (22.9%), and 33 implants were 13 mm (30.3%). There was no statistical difference between the abutment diameters (p > 0.05). Within the limitations of this study, it was possible to conclude that better behavior and lesser marginal bone loss were observed when using abutment heights greater than 2.5 mm of transmucosal portion and when placed implants with 13 mm length. Furthermore, this type of abutment showed a little incidence of failures within the period analyzed in our study.

Influence of different mucosal phenotype on early and long-term marginal bone loss around implants: a systematic review and meta-analysis

OBJECTIVES

To investigate the influence of different mucosal phenotypes on peri-implant marginal bone loss.

MATERIALS AND METHODS

The search was conducted in five databases including PubMed, Embase, Cochrane, Scopus, and Web of Science (until 1st Sept. 2022) to identify relevant clinical studies. Potentially relevant journals were also manually searched. Two reviewers independently screened studies, extracted data, and evaluated the quality of the studies. Prospective clinical trials and observational studies investigating peri-implant marginal bone loss in thick-mucosa and thin-mucosa groups were included.

RESULTS

A total of 14 studies were included in this systematic review. Results of the meta-analysis revealed a weighted mean difference of 0.38 mm for marginal bone loss between thick- and thin-mucosa groups (95% confidence interval = 0.02-0.74, P = 0.002). Statistical significance existed in short-term (follow-up ≤ 1 year) data (WMD = 0.41 mm, 95%CI = 0.11-0.70, P = 0.007), but not in long term (follow-up ≥ 3 y) data (WMD = 0.17 mm, 95%CI = - 0.02-0.36, P = 0.07). Survival rate revealed no difference between thick and thin mucosa groups. In subgroup analyses, a positive association between thick mucosa and less marginal bone loss was found in the non-submerged group, cement-retained group, and bone-level group.

CONCLUSIONS

A significantly less marginal bone loss occurred in implants with thick mucosa than with thin mucosa in the short term, whereas no significant difference was observed in the long term. Due to the substantial heterogeneity and limited long-term data, further high-quality evidence is warranted to confirm the results.

CLINICAL RELEVANCE

Clinicians are advised to use caution in treating patients with thin mucosa and adhere closely to indications and protocols to minimize marginal bone loss.

Potential Impact of Prosthetic Biomaterials on the Periodontium: A Comprehensive Review

The success of a prosthetic treatment is closely related to the periodontal health of the individual. The aim of this article was to review and present the importance of prosthetic restorative materials on the condition of the periodontium, the changes that occur in the composition of the subgingival microbiota and the levels of inflammatory markers in gingival crevicular fluid. Articles on the influence of different prosthetic restorative materials on subgingival microbiota and proinflammatory cytokines were searched for using the keywords "prosthetic biomaterials", "fixed prosthesis", "periodontal health", "subgingival microbiota", "periodontal biomarkers" and "gingival crevicular fluid" in PubMed/Medline, Science Direct, Scopus and Google Scholar. The type of material used for prosthesis fabrication together with poor marginal and internal fit can result in changes in the composition of the subgingival microbiota, as well as increased accumulation and retention of dentobacterial plaque, thus favoring the development of periodontal disease and prosthetic treatment failure. Biological markers have helped to understand the inflammatory response of different prosthetic materials on periodontal tissues with the main purpose of improving their clinical application in patients who need them. Metal-free ceramic prostheses induce a lower inflammatory response regardless of the fabrication method; however, the use of CAD/CAM systems is recommended for their fabrication. In addition, it is presumed that metal-ceramic prostheses cause changes in the composition of the subgingival microbiota producing a more dysbiotic biofilm with a higher prevalence of periodontopathogenic bacteria, which may further favor periodontal deterioration.

An Experimental Anodized Titanium Surface for Transgingival Dental Implant Elements-Preliminary Report

The characteristics such as microtopography, physical and chemical properties influence the behavior of an implant in a soft tissue. Anodization-as a potent method of titanium alloy surface modification-of the transgingival abutment or healing screw, has achieved some improvement. One of the possible surface treatment method is low-pressure radiofrequency oxygen plasma treatment. The aim of the study was to evaluate the chemical properties and cytocompatibility of the experimental surface. Titanium discs made of grade-23 titanium alloy (Ti-6Al-4V) anodized (A sample) with different voltage parameters (28, 67, 78, and 98 V) were included in the study. Half of the samples regarded as the "S" group were additionally treated with low-pressure radiofrequency oxygen plasma treatment. The surfaces were characterized using scanning electron microscopy, X-ray spectroscopy and Raman spectroscopy, and electrochemically investigated via a corrosion test. Furthermore, two cell lines were used, including the CHO-compatible reference line and a primary human fibroblast line for the MTT assay; direct (contact) cytotoxicity of the materials was tested with the cells, and the growth of fibroblasts on the surfaces of the different materials was tested. The morphology of the "S"-treated samples did not differ from the morphology of only-anodized samples. However, the oxygen concentration on the surface in that group slightly increased by about 1% as a result of post-trial treatment. The highest corrosion resistance was observed for both A-78 V and S-78 V samples. The cytotoxicity assay revealed no changes in cell morphology or vitality. The MTT test proved comparable culture viability among all groups; however, the "S" samples showed statistically significantly higher fibroblast proliferation and adhesion scores compared to the "A" samples. Through the in vitro study, the low-pressure radiofrequency oxygen plasma treatment of the anodized Ti-6Al-4V alloy presented itself as an auspicious option in the field of transgingival element surface modification of implants.

The effect of loading time on marginal bone change of implants immediately placed after extraction: a retrospective study

BACKGROUND

The purpose of this study is to compare and analyze the treatment outcomes between two groups which are both immediately placed implant cases, one is immediate loading, and the other is conventional loading group.

METHODS

Medical records of the patients who underwent implant treatment which were immediately placed after tooth extraction were analyzed. Demographic data were collected and by using periapical or panoramic radiographic image, marginal bone level and distant crestal bone level were measured. Marginal bone change over time was analyzed and compared between immediate loading group and conventional loading group.

RESULTS

A total of 71 patients, 112 immediately placed implants after tooth extraction were initially involved. Measuring was done with implants which had not failed (81). 10 implants were had failed and removed. The others were excluded because of follow-up loss, absence of radiographic image, etc. Demographic data were collected, and measured values were averaged at each follow-up and showed in linear graphs.

CONCLUSIONS

In case of immediate implantation of dental implant after extraction, loading time could affect marginal bone level or biological width of the implant. Immediate loading group showed 0.92 mm (mean value) more bone loss compared to conventional loading group at bone-implant contact points 24 months after implantation. At distant crestal points, there was no noticeable difference in bone change pattern between two groups.

Biomimetic materials based on zwitterionic polymers toward human-friendly medical devices

This review summarizes recent research on the design of polymer material systems based on biomimetic concepts and reports on the medical devices that implement these systems. Biomolecules such as proteins, nucleic acids, and phospholipids, present in living organisms, play important roles in biological activities. These molecules are characterized by heterogenic nature with hydrophilicity and hydrophobicity, and a balance of positive and negative charges, which provide unique reaction fields, interfaces, and functionality. Incorporating these molecules into artificial systems is expected to advance material science considerably. This approach to material design is exceptionally practical for medical devices that are in contact with living organisms. Here, it is focused on zwitterionic polymers with intramolecularly balanced charges and introduce examples of their applications in medical devices. Their unique properties make these polymers potential surface modification materials to enhance the performance and safety of conventional medical devices. This review discusses these devices; moreover, new surface technologies have been summarized for developing human-friendly medical devices using zwitterionic polymers in the cardiovascular, cerebrovascular, orthopedic, and ophthalmology fields.

Peri-Implant Bone Loss and Overload: A Systematic Review Focusing on Occlusal Analysis through Digital and Analogic Methods

The present review aimed to assess the possible relationship between occlusal overload and peri-implant bone loss. In accordance with the PRISMA guidelines, the MEDLINE, Scopus, and Cochrane databases were searched from January 1985 up to and including December 2021. The search strategy applied was: (dental OR oral) AND implants AND (overload OR excessive load OR occlusal wear) AND (bone loss OR peri-implantitis OR failure). Clinical studies that reported quantitative analysis of occlusal loads through digital contacts and/or occlusal wear were included. The studies were screened for eligibility by two independent reviewers. The quality of the included studies was assessed using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool. In total, 492 studies were identified in the search during the initial screening. Of those, 84 were subjected to full-text evaluation, and 7 fulfilled the inclusion criteria (4 cohort studies, 2 cross-sectional, and 1 case-control). Only one study used a digital device to assess excessive occlusal forces. Four out of seven studies reported a positive correlation between the overload and the crestal bone loss. All of the included studies had moderate to serious overall risk of bias, according to the ROBINS-I tool. In conclusion, the reported data relating the occlusal analysis to the peri-implant bone level seem to reveal an association, which must be further investigated using new digital tools that can help to standardize the methodology.

Nonthermal Plasma Brush Treatment on Titanium and Zirconia To Improve Periabutment Epithelium Formation

The peri-implant soft tissue with inferior adhesion takes a long healing period to form, which is undesirable for the reaction around the peri-implant soft tissues. The aim of this study is to improve the physicochemical properties of titanium (Ti) and zirconia (ZrO₂) implant abutments and shorten the formation period of periabutment epithelium tissue. A nonthermal atmospheric plasma brush (NTAPB, N) was employed for Ti and ZrO₂ activation. The surface topographies, roughness, crystallinity, wettability, and chemical elements of the abutment materials were examined. The epithelial cell behavior analysis and tissue remodeling of the periabutment epithelial tissue were performed in vitro and in vivo. N-Ti and N-ZrO₂ had a similar good surface wettability, with a 65 and 70% increase in oxygen content and a 70 and 75% decrease in carbon content, respectively. Both N-Ti and N-ZrO₂ showed excellent adhesion, spread, and proliferation of epithelial cells in vitro, with improved adhesion molecule expression levels compared to untreated samples. N-Ti and N-ZrO₂ abutments were placed in the implantation sites of rats. From week 2 to week 6 after implantation, N-Ti and N-ZrO₂ had similar periabutment epithelium tissue formation, and both had increased plectin-positive and laminin γ2-positive cell numbers compared to Ti and ZrO₂. The NTAPB shows promising abutment modification abilities. It promotes the expression levels of adhesion molecules and the epithelial cell performance, which later leads to a quicker formation and remodeling of the important periabutment epithelial tissue.

Antibacterial Effects of Modified Implant Abutment Surfaces for the Prevention of Peri-Implantitis-A Systematic Review

The aim of the present study was to systematically review studies investigating antibacterial implant abutment surfaces or coatings, which may suppress bacterial growth to prevent plaque-induced peri-implant inflammatory disease. Data were collected after identification of case, assay/laboratory procedure, predicate/reference standard and outcome (CAPO). Seven hundred and twenty (720) records were identified through data base searching. After screening nine publications fulfilled inclusion criteria and were included. The following surfaces/coatings showed antibacterial properties: Electrochemical surface modification of titanium by the anodic spark deposition technique; doxycycline coating by cathodic polarization; silver coating by DC plasma sputter; titanium nitride; zirconium nitride and microwave assistant nano silver coating. Since the current state of the literature is rather descriptive, a meta-analysis was not performed. While several abutment coatings showed to have antibacterial capacity, some of them also influenced the behavior of investigated human cells. None of the studies investigated the long-term effect of surface modifications. Since surface changes are the main contributing factor in the development of antibacterial effects, the biodegradation behavior must be characterized to understand its durability. To date there is no effective structure, material or strategy to avoid peri-implant inflammation used as clinical routine. Furthermore, clinical studies are scarce.