Transcriptome analysis of granulation tissue from periodontal osseous defects

BACKGROUND

Granulation tissue is routinely discarded in periodontal surgical procedures, but few studies have characterized it. The present study aimed to compare global gene expression in granulation tissue derived from different types of periodontal osseous defects.

METHODS

Total RNA was isolated from granulation tissue harvested during routine periodontal surgical procedures. Nineteen sites were analyzed-seven infrabony, six suprabony, and six furcation defects. Following quality control checks, samples underwent bulk mRNA sequencing (20-30 million read pairs per sample) before bioinformatic analyses utilizing gene ontology and associated pathway/enrichment analyses.

RESULTS

No statistically significant differentially expressed genes (DEG) were detected between different osseous defect types. An increase in the expression of 11 genes with a false discovery rate of <0.05 was detected when a comparison was made in terms of healing duration post nonsurgical periodontal therapy (NSPT). Notably, the genes involved included those regulating collagen synthesis and osteogenic activity. Analysis based on sex differences revealed 38 DEG. Gene enrichment analysis revealed that 24 DEG without Y-linked attachment are mostly involved in immune regulation.

CONCLUSIONS

Routinely discarded periodontal granulation tissue exhibits epithelial characteristics due to a substantial period of maturation post NSPT. Confirmation of ongoing maturation beyond traditional periodontal re-evaluation timepoints warrants further investigation on tissue differentiation potential. More research is needed to elucidate the role of sex as a biological variable affecting periodontal immune response.

PLAIN LANGUAGE SUMMARY

Granulation (wound) tissue is routinely removed during gum (periodontal) surgical procedures, but knowledge on its characteristics is scarce. This study aimed to compare gene expression in granulation tissue derived from different types of periodontal bone defects via high-throughput RNA sequencing. Total RNA was extracted from 95 samples harvested from gum disease patients during surgery. After quality control checks, 19 samples (seven infrabony, six suprabony, and six furcation defects) were eligible for sequencing. Subsequent analyses were done utilizing software with known cell biological pathways and processes. Analysis revealed no differentially expressed genes (DEG) in terms of periodontal defect category. There was statistically significantly increased expression of 11 genes when a comparison was made in terms of healing duration following deep scaling treatment. These genes are involved in collagen synthesis and osteogenic activity. Interestingly, analysis based on sex differences detected 38 DEG. Gene enrichment analysis revealed that 24 DEG without association with Y chromosomes are mostly involved in the regulation of immune system response. Routinely discarded periodontal granulation tissue exhibits lining cell characteristics that change over time following deep scaling treatment. More research is needed to unravel the role of sex as a biological variable affecting periodontal immune response in this type of tissue.

Tri-Layer Citrate-Based Hydroxyapatite Composite Scaffold Promoting Osteogenesis and Gingival Tissue Regeneration for Periodontal Bone Defect Repair

Periodontal bone defect (PBD) treatment involving oral soft and hard tissues is complicated and high requirements for regenerated materials. Besides osteogenic effects, the materials are also required to have the function of barrier soft tissues and promote wound healing. Citrate is reported to promote bone formation through enhanced osteoinductivity and facilitate wound healing by enabling phased angiogenesis. Herein, a novel tri-layered citrate-based hydroxyapatite (Ci-HA) composite scaffold that serves as a bone substitute is developed by "one-pot" method for PBD treatment. It is found that Ci-HA degradation products can promote the osteoblastic differentiation of rat bone mesenchymal stem cells and human periodontal ligament stem cells and upregulate angiogenesis-related gene expression in human gingival fibroblasts. Moreover, 3D remodeling in vitro shows that an intermediate layer of tri-layered Ci-HA composite scaffold acts as an optimal barrier. In vivo evaluation of Ci-HA in a rat periodontal intrabony three-wall defect model shows significantly increased bone formation with markedly enhanced osseointegration and better wound healing properties similarly with commercial Bio-Oss bone powder and Bio-Gide membrane. Thus, the novel tri-layered Ci-HA composite scaffold with high biocompatibility may represent a promising biomaterial with multi-effective bone regeneration, barrier effect, and wound healing capacity in the treatment of PBD.

Selective modulation of the bone remodeling regulatory system through orthodontic tooth movement-a review

Little is known about how tissues mediate the ability to selectively form or resorb bone, as required during orthodontic tooth movement (OTM), facial growth, continued tooth eruption and for healing after fractures, maxillofacial surgical repositioning or implant dentistry. OTM has the unique ability to selectively cause apposition, resorption or a combination of both at the alveolar periosteal surface and therefore, provides an optimal process to study the regulation of bone physiology at a tissue level. Our aim was to elucidate the mechanisms and signaling pathways of the bone remodeling regulatory system (BRRS) as well as to investigate its clinical applications in osteoporosis treatment, orthopedic surgery, fracture management and orthodontic treatment. OTM is restricted to a specific range in which the BRRS permits remodeling; however, surpassing this limit may lead to bone dehiscence. Low-intensity pulsed ultrasound, vibration or photobiomodulation with low-level laser therapy have the potential to modify BRRS with the aim of reducing bone dehiscence and apical root resorption or accelerating OTM. Unloading of bone and periodontal compression promotes resorption via receptor activator of nuclear factor κB-ligand, monocyte chemotactic protein-1, parathyroid hormone-related protein (PTHrP), and suppression of anti-resorptive mediators. Furthermore, proinflammatory cytokines, such as interleukin-1 (IL-1), IL-6, IL-8, tumor necrosis factor-α, and prostaglandins exert a synergistic effect on bone resorption. While proinflammatory cytokines are associated with periodontal sequelae such as bone dehiscence and gingival recessions, they are not essential for OTM. Integrins mediate mechanotransduction by converting extracellular biomechanical signals into cellular responses leading to bone apposition. Active Wnt signaling allows β-catenin to translocate into the nucleus and to stimulate bone formation, consequently converging with integrin-mediated mechanotransductive signals. During OTM, periodontal fibroblasts secrete PTHrP, which inhibits sclerostin secretion in neighboring osteocytes via the PTH/PTHrP type 1 receptor interaction. The ensuing sclerostin-depleted region may enhance stem cell differentiation into osteoblasts and subperiosteal osteoid formation. OTM-mediated BRRS modulation suggests that administering sclerostin-inhibiting antibodies in combination with PTHrP may have a synergistic bone-inductive effect. This approach holds promise for enhancing osseous wound healing, treating osteoporosis, bone grafting and addressing orthodontic treatments that are linked to periodontal complications.

Advances in periodontal healing biomarkers

Periodontitis is the infectious-inflammatory disease of tooth-supporting tissues. Periodontal treatment, either non-surgical or surgical, aims to remove infection, reduce inflammation, eliminate tissue loss, and gain clinical attachment. Clinical and radiographic recordings are widely used and accepted as gold-standard methods in periodontal diagnostics. While these traditional methods allow clinicians to monitor and diagnose periodontitis, they cannot be used to estimate the course of periodontal healing, or predict the disease recurrence or estimate the treatment outcome. Early prediction of the long-term consequences of periodontal treatment would be a crucial and valuable information not only for the clinicians, but also for the patients. Rapid advancements during past few decades boosted the periodontal biomarker studies and various microbe- or host-derived biochemical markers have been suggested as diagnostic biomarkers of periodontitis. Yet, there is no consensus regarding the accuracy of diagnostic biomarkers to monitor treatment response or to predict prognosis. The aim of this chapter will be to describe the healing patterns of periodontal tissues after treatment and present the available evidence on biomarkers that can indicate or predict successful treatment outcomes.

Apical horizontal incision with periosteum graft wall technique for periodontal regeneration: A case study

BACKGROUND

The periosteum consists of an outer fibrous layer and an inner cellular layer, where bone cells reside. Hence, it has been suggested that applying periosteum to a periodontal defect may help new bone formation. The purpose of this case study is to present the clinical and radiographic outcomes of a vestibular regenerative approach and the application of a connective tissue graft (CTG) with periosteum to improve the periodontal prognosis of a pathologically migrated hopeless tooth with an endo-periodontal lesion (EPL).

METHODS

A 35-year-old female presented with a hopeless tooth with EPL on #9. To preserve the papilla, a horizontal incision with two vertical releasing incisions was made on the buccal vestibule where the buccal bone was present. A CTG with periosteum was harvested from the tuberosity area. After applying enamel matrix derivative (EMD) and freeze-dried bone allograft (FDBA), the CTG was placed over the defect and stabilized with absorbable sutures. The flap was replaced and sutured, achieving primary closure and healing by primary intention.

RESULTS

Following regenerative procedure, a localized orthodontic treatment was applied. A minimal ridge resorption, shallow probing depth, and radiographic stability of periodontal bone level were observed.

CONCLUSION

This case study shows the successful application of a multidisciplinary approach to save a hopeless tooth with severe bone destruction and a non-contained periodontal defect.

KEY POINTS

Multi-disciplinary approach including endodontic, orthodontic, and periodontal regenerative procedure can improve the prognosis of natural teeth. It would be beneficial to maintain the blood supply to the crestal part of the flap with apical incision. Connective tissue graft with periosteum could enhance the healing potential when used in adjunct with periodontal regeneration.

PLAIN LANGUAGE SUMMARY

The apical horizontal incision combined with periosteum graft could successfully save a tooth with severe bone destruction and a non-contained periodontal defect. The importance of wound stability on the papillae area was achieved with the vestibular approach with application of the room concept. This method would be beneficial to improve the periodontal prognosis of a severely periodontally compromised tooth.

Novel triangle papilla access approach for interdental bone defect regeneration: A case study

BACKGROUND

Successful periodontal regeneration depends on primary wound closure and interdental papilla preservation. In this case study, we introduce a novel triangle papilla access approach (T-PAA) performed under a surgical microscope for treating interdental bone defects. In this novel approach, buccal incisions were used to access root surfaces and bone defects, avoiding interdental papilla incisions and preventing papillary collapse and necrosis.

METHODS

Nine patients with a mean age of 56 years were enrolled in this study. Incisions were made to create a triangular flap, which was reflected using a micro-periosteal elevator to expose the bone defect and granulation tissue. Subsequently, the granulation tissue was removed from the bone defect using a microsurgical blade, followed by root debridement using ultrasonic and micro-hand scalers and root conditioning. Thereafter, a mixture of fibroblast growth factor-2 and carbonated apatite granules was applied to the bone defect. The triangular flap was repositioned to ensure that the apex was not lifted by the graft material, and from the flap apex, 7-0 nylon sutures were used, followed by the addition of mesial and distal sutures. Adjacent teeth were splinted using wire and resin cement.

RESULTS

Postoperatively, clinical and radiographic evaluations at 6 months and 1 year showed significant improvements in periodontal parameters and bone filling. All patients achieved primary wound closure with no postoperative complications.

CONCLUSIONS

T-PAA is a promising approach for periodontal regeneration, providing adequate surgical access under a surgical microscope while preserving the papilla and potentially improving clinical outcomes in patients with interdental bone defects.

KEY POINTS

Triangle papilla access approach (T-PAA) provides adequate surgical access, preserves the interdental papillae, and improves clinical outcomes in cases of interdental bone defects. Triangular incisions made in areas with abundant blood flow and thicker gingiva at the base of the papilla are less likely to impair blood supply to the interdental papillae. T-PAA facilitates effective debridement, precise placement of regenerative materials, and accurate flap repositioning regardless of the defect morphology in localized interdental areas.

PLAIN LANGUAGE SUMMARY

Successful periodontal treatment often requires surgical procedures for bone regeneration in patients with bone defects. However, traditional surgical approaches may damage the interdental papillae, leading to esthetic concerns and compromised healing. In this study, we introduced a new surgical technique called the triangle papilla access approach, which uses a specially designed triangular incision to access and treat bone defects under a surgical microscope while preserving the interdental papillae. Our results from nine patients demonstrated that this technique effectively maintained tissue health and promoted bone regeneration. Therefore, it could become a more efficient approach for treating interdental bone defects.

Early wound healing in guided bone regeneration procedures using sodium hyaluronate and a pool of amino acids: a randomized clinical trial

BACKGROUND

Soft tissue healing is of paramount importance when guided bone regeneration techniques are used, as early exposure of the membrane could affect the results.

METHODS

In this randomized clinical trial, enrolling 20 patients, a gel rich in hyaluronic acid and amino acids was used to promote wound healing after a ridge augmentation procedure. The Early Wound Healing Index - EHS was used to assess soft tissue healing by primary intention following surgery at 1, 3, 7 and 14 days.

RESULTS

Results showed faster tissue healing when hyaluronic acid mixed with amino acids was used, and also a lower perception of pain by patients measured with a VAS scale.

CONCLUSIONS

These data suggest the creation of larger research studies that can support the use of biologics for early soft tissue healing.

The nasal spine suture: A novel approach for membrane stabilization

BACKGROUND

Current evidence acknowledges guided bone regeneration (GBR) as a predictable therapeutic modality in the augmentation of a deficient alveolar ridge. Such deficiencies often reveal inadequate bone volume to support implant placement in a position amenable to prosthetic reconstruction. Additionally, an evolving body of literature demonstrates that membrane fixation may lead to improved clinical bone gain through positively influencing blood clot formation, stability, and the eventual osteogenic potential of the defect. Alternative benefits to membrane fixation, such as reduced graft displacement and reduction in wound micromotion, have also been cited as mechanisms for an increased regenerative response.

METHODS AND RESULTS

The aim of this report was to present a case, including diagnosis, treatment, and follow-up for the reconstruction of a horizontal ridge deficiency. The patient's deficiency in ridge volume was found to be a developmental sequelae of lateral incisor agenesis, resulting in an underdeveloped midfacial region of the alveolar process subjacent to sites #7 and #10. The fixation protocol outlined in this report demonstrated adequate horizontal ridge augmentation to facilitate future prosthetic reconstruction with the use of implants.

CONCLUSIONS

Numerous protocols have been established in an attempt to achieve effective barrier membrane stabilization for bone augmentation procedures. However, some techniques are poorly suited for the anatomically challenging region of the anterior maxilla. A case report describing the utilization of the anterior nasal spine for anchorage of a membrane-stabilizing suture may present a novel, safe, and effective technique for stabilizing the intended region of augmentation, as well as preventing graft migration beyond the membrane-maxilla interface. Key points Regarding guided bone regeneration (GBR) procedures, micromotion of the membrane or of the underlying particulate graft may negatively influence the volume of the augmented site. The ability to adequately stabilize the graft-membrane interface is recognized as a necessary prerequisite to predictably achieve optimal surgical outcomes. To the authors' knowledge, there is no clinical or scientific evidence regarding the use of the anterior nasal spine for membrane anchorage in maxillary GBR procedures, and thus a novel approach to membrane stabilization is introduced.

Subcrestal incision: An alternative flap design for dental implant placement - A randomized controlled split-mouth design clinical trial

Objective

This randomized controlled trial aimed at comparing a novel incision design with a conventional mid-crestal incision design for implant placement to achieve complete closure of the surgical site.

Background

Proper flap margin approximation is pivotal for surgical wound healing in patients undergoing dental implant treatment with or without bone augmentation.

Materials and Methods

A clinical study was conducted at the department of implantology with a total number of 30 patients. Patients with bilateral edentulous sites for whom dental implant placement was planned were included in the study. Mid-crestal incision design on one side and subcrestal incision design on other side were performed. Healing was evaluated at 1- and 4-week intervals postoperatively using an early wound healing score (EHS). The pain perception from the patient was also noted after 1 week on the day of suture removal using Visual Analogue Scale (VAS) values ranging from 0 to 10.

Results

Wound healing in the subcrestal incision design sites were showing higher EHS at 1-week and 4-week intervals, which was statistically significant when compared to the sites with mid-crestal incision design. VAS values were also showing higher pain perception toward mid-crestal incision design over subcrestal incision design.

Conclusion

With the limitations of the present study, it can be concluded that subcrestal incision design stands as a promising flap design over mid-crestal incision design for dental implant placement.

Micro-needling versus acellular dermal matrix in RT1 gingival recession coverage: A randomized clinical trial

AIMS

This randomized trial assessed for the first time the efficacy of coronally advanced flap (CAF) followed by micro-needling (MN) in contrast to CAF with acellular dermal matrix (ADM) on gingival thickness (GT, primary outcome), keratinized tissue width (KTW), clinical attachment level (CAL), probing depth (PD), recession depth (RD), recession width (RW), recession reduction (Rec-Red), complete root coverage (CRC) and percentage of root coverage (all secondary outcomes) in management of RT1 gingival recession in patients with thin gingival phenotype.

METHODS

A total of 24 patients (n = 24) with a thin gingival phenotype and single RT1 gingival recession in the aesthetic zone were randomly allocated to test- (CAF + MN; n = 12) or control group (CAF + ADM; n = 12). All clinical parameters were evaluated at baseline, 3 and 6 months.

RESULTS

Both groups independently demonstrated significant gain in GT, RW, RD, CAL, PD, Rec-Red, CRC and percentage of root coverage, with reduced PI and BOP (p < .05) at 3 and 6 months, without intergroup differences (p > .05). At 6 months, KTW gain was significantly higher in CAF + MN (5.08 ± 0.9 mm) than in CAF + ADM-group (4.25 ± 1.06 mm; p < .05). Stepwise linear regression model with GT as dependent variable showed that base-line GT was the only statistically significant predictor for GT with a direct correlation between base-line GT and GT after 6 months.

CONCLUSION

CAF followed by MN could represent a promising graft-less approach for increasing gingival thickness, comparable to CAF with ADM, with superior keratinized tissue width improvement, in the treatment of RT1 recession defects in patients with thin gingival phenotype.

Expression of wound healing markers in gingival crevicular fluid following root-coverage procedures: A systematic review of randomized clinical trials

OBJECTIVE

Although several surgical techniques have been developed for treatment of gingival recession (GR), the underlying wound healing process remains relatively unexplored. This systematic review aimed to investigate the expression of wound healing markers in gingival crevicular fluid (GCF) before and after surgical treatment of GR.

DESIGN

Randomized clinical trials (RCTs) reporting changes in the expression of GCF markers following any root coverage surgical procedure were identified from 4 electronic databases and manual searches followed by data extraction and result synthesis. The risk of bias (RoB) was assessed using Cochrane RoB 2.0 tool. Overall certainty of evidence was summarized using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool.

RESULTS

Four RCTs comprising 100 patients and investigating 15 biomarkers were included. Post-surgery, GCF levels of cytokines and inflammatory proteins were raised during the first 2-10 days of healing. MMP-8 levels increased during the first week followed by a gradual decline. RoB was found to be high for all studies and the overall certainty of evidence was very low.

CONCLUSION

A limited number of studies with large methodological variations precluded reliable conclusions. Well-designed studies powered for GCF markers' levels that follow a standardized protocol for GCF sampling and processing are needed to draw conclusive evidence.

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.

Partial (incomplete) removal of granulation tissue using modified minimally invasive surgical technique in treatment of infrabony defects (randomized control clinical trial)

AIM

This study aims to compare the clinical and radiographic outcomes after complete versus incomplete removal of granulation tissue (GT) during modified minimally invasive surgical technique (M-MIST) for management of periodontitis patients with deep pockets associated with infra-bony defects.

METHODOLOGY

Ten patients with a total of 14 deep non-resolving pockets (≥ 5 mm) associated with a vertical infra-bony defect were recruited for this study. They were randomized into 2 groups; a test group with incomplete removal of GT and a control group with complete removal of GT. Clinical parameters of clinical attachment level (CAL), residual probing depth (rPD) and buccal recession (Rec.) were recorded every 3 months. Radiographic periapicals were taken at baseline, 6 and 9 months. The significance level was set to 0.05.

RESULTS

None of the results showed statistical significance between the 2 groups (p > 0.05). The test group showed less CAL gain (2 ± 0.87 mm, p = 0.062), more reduction in rPD (3.1 ± 0.96 mm, p = 0.017) and more recession (0.857 ± 0.26 mm, p = 0.017) than control group CAL gain (2.4 ± 0.58 mm, p = 0.009), rPD reduction (2.9 ± 0.3 mm, p = 0.001) and recession (0.5 ± 0.34 mm, p = 0.203) respectively. Control group had linear reduction in depth defect (DD) (0.68 ± 0.287, p = 0.064) compared to an increase in DD in test group (-0.59 ± 0.5, p = 0.914).

CONCLUSIONS

No statistical significance were observed in healing parameters between complete removal of GT in M-MIST and incomplete (partial) removal of GT of deep pockets with infra-bony defects both clinically and radiographically. Further studies with larger samples are needed to confirm the results.

Evaluation of Peri-Implantitis Bone Defect Healing: Comparing the Efficacy of Small-Particle Dentin and Bio-Oss in Bone Density Attenuation

Introduction: Peri-implantitis is a serious complication in dental implantology that, if left untreated, may lead to implant loss and systemic diseases. Effective regeneration of bone defects resulting from peri-implantitis is crucial to maintaining the functionality of dental implants. Purpose of the Study: The study aimed to compare the effectiveness of fine-particle dentin and Bio-Oss in the reconstruction of bone defects caused by peri-implantitis. Materials and Methods: The study included a comprehensive radiological assessment of changes in bone density over time. Bone density was assessed using Hounsfield Units (HUs) as a measure of bone attenuation, with radiological assessments performed at 8- and 12-week intervals during the healing process. The study included participants ranging in age from 30 to 65 years. Fifty-seven patients were divided into three groups: 22 patients received small-particle dentin, 15 received Bio-Oss, and 20 controls without bone substitute material. Results: The fine-dentin group showed a 20% increase in bone density after 8 weeks (p < 0.05), while the Bio-Oss group showed a 15% increase after 12 weeks (p < 0.05). The control group showed minimal changes in bone density (5% after 12 weeks), which was not statistically significant. Clinical evaluations showed 95% successful integration in the fine dentin group, 85% in the Bio-Oss group, and 70% in the control group. The fine-dentin group showed a 20% increase in bone density after 8 weeks (p < 0.05), while the Bio-Oss group showed a 15% increase after 12 weeks (p < 0.05). The control group showed minimal changes in bone density (5% after 12 weeks), which was not statistically significant. Clinical evaluations showed 95% successful integration in the fine-dentin group, 85% in the Bio-Oss group, and 70% in the control group. Conclusions: Both fine-particle dentin and Bio-Oss significantly improved bone density compared to the control group. Fine-particle dentin is suitable for immediate bone regeneration due to its rapid initial regeneration, while Bio-Oss provides long-term support, ideal for maintaining implant stability over a longer period of time. The results highlight the importance of selecting appropriate bone replacement materials depending on the clinical scenario to improve patient outcomes after dental implant placement.

Periodontal granulation tissue - To remove or not to remove, that is the question

Formation of granulation tissue is a fundamental phase in periodontal wound healing with subsequent maturation leading to regeneration or repair. However, persistently inflamed granulation tissue presents in osseous defects as a result of periodontitis and is routinely disrupted and discarded with non-surgical and surgical therapy to facilitate wound healing or improve chances of regeneration. Histological assessment suggests that granulation tissue from periodontitis-affected sites is effectively a chronic inflammatory tissue resulting from impaired wound healing due to persistence of bacterial dysbiotic bioflim. Nevertheless, the immunomodulatory potential and stem cell characteristics in granulation tissue have also raised speculation about the tissue's regenerative potential. This has led to the conception and recent implementation of surgical techniques which preserve granulation tissue with the intention of enhancing innate regenerative potential and improve clinical outcomes. As knowledge of fundamental cellular and molecular functions regulating periodontitis-affected granulation tissue is still scarce, this review aimed to provide a summary of current understanding of granulation tissue in the context of periodontal wound healing. This may provide new insights into clinical practice related to the management of granulation tissue and stimulate further investigation.

Enhancement of Biocompatibility of High-Transparency Zirconia Abutments with Human Gingival Fibroblasts via Cold Atmospheric Plasma Treatment: An In Vitro Study

The objective of this study was to explore the effects of cold atmospheric plasma (CAP) treatment on the biological behavior of human gingival fibroblasts (HGFs) cultured on the surface of high-transparency zirconia. Two types of zirconia, 3Y-ZTP and 4Y-PSZ, were subjected to a CAP treatment for various treatment durations. Analyses of the physical and chemical properties of 3Y-ZTP and 4Y-PSZ were conducted using scanning electron microscopy, contact angle measurements, and X-ray photoelectron spectroscopy, both before and after CAP treatment. The biological responses of HGFs on both surfaces were assessed using CCK-8 assay, confocal laser scanning microscopy, and real-time PCR. Initially, the oxygen and hydroxyl contents on the surface of 4Y-PSZ exceeded those on 3Y-ZTP. CAP treatment enhanced the surface hydrophilicity and the reactive oxygen species (ROS) content of 4Y-PSZ, while not altering the surface morphology. After CAP treatment, HGFs' adhesion on 4Y-PSZ was superior, with more pronounced effects compared to 3Y-ZTP. Notably, HGFs counts and the expression of adhesion-related genes on 4Y-PSZ peaked following the CAP exposures for 30 s and 60 s. Consequently, this study demonstrates that, following identical CAP treatments, 4Y-PSZ is more effective in promoting HGFs adhesion compared to traditional 3Y-ZTP zirconia.

The distance of insertion points from wound margins in interrupted and vertical mattress sutures influences the tensile load capacity: An in vitro experimental study

AIM

To determine the tensile load capacity (TLC) and the tearing characteristics for interrupted and vertical mattress sutures with different insertion points from the wound margin, and the effect of the bite size when using vertical mattress sutures.

MATERIALS AND METHODS

A total of 120 gingiva and lining mucosa samples obtained from pig jaws were divided into groups according to the suturing technique (interrupted and vertical mattress sutures), distance of the insertion points from the wound margin (margin, 1, 3, and 5 mm) and bite size (1, 3, and 5 mm). The TLC of the suture and the tearing characteristics were evaluated using a tensile tester device.

RESULTS

The TLC was significantly higher for vertical mattress sutures than for interrupted sutures regardless of the distance of the insertion points from the wound margin (intergroup p < .001). This distance significantly influenced the TLC for vertical mattress sutures (p < .05) but not for interrupted sutures (p > .05). Testing the tearing characteristics revealed that no tissue tearing occurred in groups when the insertion points were more than 3 mm from the wound margin.

CONCLUSION

The TLC is higher for vertical mattress sutures than for interrupted sutures, and it increases when the insertion points are farther from the wound margin.

Modified approach of regenerative treatment for distal intrabony defect beneath non-keratinized mucosa at terminal molar: A case report

BACKGROUND

Intrabony defects beneath non-keratinized mucosa are frequently observed at the distal site of terminal molars. Consequently, the application of regenerative treatment using the modified wedge-flap technique is considered impractical for these specific dental conditions.

CASE SUMMARY

This article proposes a modified surgical procedure aimed at exposing the distal intrabony defect by making a vertical incision in the keratinized buccal gingiva. The primary objective is to maintain gingival flap stability, thereby facilitating periodontal regeneration. The described technique was successfully employed in a case involving the left mandibular second molar, which presented with an intrabony defect without keratinized gingiva at the distal site. In this case, an incision was made on the disto-buccal gingival tissue, creating a tunnel-like separation of the distal non-keratinized soft tissue to expose the intrabony defect. Subsequently, bone grafting and guided tissue regeneration surgeries were performed, resulting in satisfactory bone fill at 9 mo postoperatively.

CONCLUSION

This technique offers a regenerative opportunity for the intrabony defects beneath non-keratinized mucosa and is recommended for further research.

[The use of alginate plates with a complex of antimicrobial peptides and cytokines after surgical interventions on periodontal tissues as a prevention of early postoperative complications]

OBJECTIVE

To evaluate the possibility of improving the effectiveness of early postoperative healing in patients after surgical interventions on periodontal tissues due to the topical application of alginate plates with a complex of antimicrobial peptides and cytokines.

MATERIALS AND METHODS

40 patients who underwent periodontal surgery were examined: operations aimed at bone tissue regeneration; mucogingival operations (elimination of gum recession), corticotomy with osteoplasty, apical surgery. The patients were randomly divided into 2 groups of 20 people (main and control). At the end of the operation, alginate plates with a complex of antimicrobial peptides and cytokines were applied to the surgical intervention area to the main group. Further, 2-3 times a day, it was recommended to apply them independently for 10-14 days, after antiseptic treatment. In the control group, they were limited to double treatment with 0.05% chlorhexidine bigluconate solution daily for two weeks. Follow-up examinations and evaluation of the index of early wound healing, as well as indicators of postoperative pain, bleeding and edema were carried out on day 3, 7, 14.

RESULTS

In all patients in the early postoperative period, positive dynamics of healing were observed, however, in the main group, pain indicators, as well as bleeding and swelling, according to a patient survey, were less pronounced. The early wound healing index was also more positive in the main group - on days 3, 7 and 14 there was a more intense decrease. (1.9 points.,1.5 points., 1.2 points., respectively, and in the control group 2.3 points., 2.1 points., 1.9 points.).

CONCLUSION

Local application of alginate plates with a complex of antimicrobial peptides and cytokines in the early postoperative period allows to improve early wound healing after surgical interventions on periodontal tissues, and can be recommended for use at a dental appointment, as well as for use at home.

Effects of the GingivalStat approach on early gingival margin remodeling following esthetic clinical crown lengthening: A case series

OBJECTIVES

The aim of this case series is to present the potential applications of the GingivalStat approach, that is, the use of temporary gingival stabilizers, to favor early gingival margin remodeling and prevent the occurrence of gingival rebound following esthetic clinical crown lengthening.

CLINICAL CONSIDERATIONS

Four patients requiring clinical crown lengthening were treated for esthetical and functional reasons. The surgical approach included: (a) gingival margin recontouring; (b) full-thickness flap elevation; (c) osteotomy (to achieve an adequate dimension between the alveolar bone crest and the CEJ) and osteoplasty (to reduce the bone thickness and improve the buccal bone anatomic profile, where indicated); (d) temporary gingival stabilizer placement using a block-out resin or a composite (the GingivalStat approach); and (e) flap repositioning, adaptation, and suture. One- to five-year follow-ups, reported in the different case scenarios, show evidence of clinically stable gingival margins around the treated teeth.

CONCLUSIONS

Within the limits of this case series, it can be concluded that the GingivalStat approach appears as a further maneuver to cope with clinical crown lengthening procedures at esthetic sites. GingivalStat seems to favor gingival margin contour remodeling during the early phase of healing as well as prevent the occurrence of gingival rebound.

CLINICAL SIGNIFICANCE

GingivalStat approach may guide gingival margin remodeling and prevent gingival rebound after wound healing of sites submitted to esthetic clinical crown lengthening.

A Case Report of Periodontal Regenerative Therapy Using Recombinant Human Fibroblast Growth Factor 2 and Deproteinized Bovine Bone Mineral with Non-incised Papillae Surgical Approach (NIPSA) for Angular Bone Defect in Patient with Stage III Grade C Periodontitis

This report describes a case of Stage III Grade C periodontitis requiring periodontal regenerative therapy. The patient was a 19-year-old woman who presented with the chief complaint of gingival recession in the incisor region. An initial examination revealed that 45.3% of sites had a probing depth of ≥4 mm and 45.8% bleeding on probing. Radiographic examination showed angular bone resorption in #25, 26, 31, 36, and 46 and horizontal resorption in other regions. Initial periodontal therapy was implemented based on a clinical diagnosis of Stage III Grade C periodontitis (generalized aggressive periodontitis). Occlusal adjustment was also performed at sites showing premature contact (#26 and 36) after suppression of inflammation. Periodontal regenerative therapy using recombinant human fibroblast growth factor (rhFGF) -2 was performed on #25, 26, and 46. Combination therapy with rhFGF-2 and deproteinized bovine bone mineral (DBBM) was performed on #31 and 36. A non-incised papillae surgical approach (NIPSA) was used on #31. Periodontal conditions were then re-evaluated and the patient placed on supportive periodontal therapy. Regenerative therapy using rhFGF-2 and DBBM with NIPSA yielded an improvement in clinical parameters and bone resorption. This improvement has been adequately maintained over a 12-month period. Continued care is needed to maintain stable periodontal conditions.

The importance of soft tissue condition in bone regenerative procedures to ensure long-term peri-implant health

Bone regenerative procedures have been widely proved to be a reliable treatment option to re-create the ideal pre-implant clinical conditions. Nevertheless, these techniques are not free from post-operative complications which might result in implant failure. Consequently, as demonstrated by the increasing recently published evidence, a careful pre- and intra-operative flap evaluation to ensure an ideal and hermetic tension-free wound closure is of paramount importance to successfully treat bony defects. In this respect, several surgical interventions mainly aimed to increase the amount of keratinized mucosa either to allow an optimal healing after a reconstructive procedure or to establish an optimal peri-implant soft tissue seal have been proposed. The present review summarizes the level of evidence on the surgical clinical aspects which have an impact on the soft tissue handling associated with bone reconstructive procedures and on the importance of soft tissue conditions to enhance and maintain peri-implant health in the long-term.

Techniques on vertical ridge augmentation: Indications and effectiveness

Vertical ridge augmentation techniques have been advocated to enable restoring function and esthetics by means of implant-supported rehabilitation. There are three major modalities. The first is guided bone regeneration, based on the principle of compartmentalization by means of using a barrier membrane, which has been demonstrated to be technically demanding with regard to soft tissue management. This requisite is also applicable in the case of the second modality of bone block grafts. Nonetheless, space creation and maintenance are provided by the solid nature of the graft. The third modality of distraction osteogenesis is also a valid and faster approach. Nonetheless, owing to this technique's inherent shortcomings, this method is currently deprecated. The purpose of this review is to shed light on the state-of-the-art of the different modalities described for vertical ridge augmentation, including the indications, the step-by-step approach, and the effectiveness.

A conceptual review on reconstructive peri-implantitis therapy: Challenges and opportunities

OBJECTIVES

The current strategies to reconstruct lost peri-implant tissues due to the disease have been largely unpredictable. The aim of this conceptual review is to discuss relevant biological and biomechanical challenges of applying reconstructive means to treat peri-implantitis. Additionally, opportunities to improve treatment predictability are presented.

MATERIAL AND METHODS

A narrative review was conducted to fulfill the aim.

RESULTS

The four interrelated negative conditions hampering effective reconstruction are: inferior tissue perfusion, unfavorable bone topography, ineffective surface treatment, and unstable wound. First, peri-implant tissues resemble scars with reduced cellularity and vascularity, coupled with the absence of the periodontal ligament plexuses and the avascular implant and biomaterials, maintaining primary closure is a challenge, which is critical for regeneration. Second, defect morphology and bone topography surrounding implants determine the reconstructive potential. Unfortunately, noncontained defects are frequently encountered, with a combination of suprabony (horizontal bone loss) and infrabony (vertical usually involving circumferential bone loss) defects. Third, current attempts for implant surface decontamination are insufficient due to inaccessible macrostructure and rough surfaces in the micro-scale. Histologic evaluation has shown bacteria aggregation and calcified deposits around implants. Lastly, wound stability is difficult to achieve due to inherent soft tissue biomechanical quality and quantity deficiencies and mobile bone particulates. Opportunities to tackle the abovementioned challenges include the use of novel imaging technologies, such as high-frequency dental ultrasound and laser speckle imaging to evaluate tissue perfusion, soft tissue quality/quantity, and bone topography pre-surgically. The use of the operating microscope could allow better visualization and removal of etiologic factors. Strategies to improve soft tissue quality may include preoperative control of soft tissue inflammation and the potential use of biologics. Methods such as fixation to stabilize the biomaterials could be beneficial.

CONCLUSIONS

A more nuanced understanding of the current challenges and opportunities can lead to more effective preoperative and postoperative care protocols, ultimately improving the success rate of reconstructive procedures.

Histological evaluation following treatment of recession-type defects with coronally advanced flap and a novel human recombinant amelogenin

OBJECTIVES

To histologically evaluate the effects of a novel human recombinant amelogenin (rAmelX) on periodontal wound healing / regeneration in recession-type defects.

MATERIALS AND METHODS

A total of 17 gingival recession-type defects were surgically created in the maxilla of three minipigs. The defects were randomly treated with a coronally advanced flap (CAF) and either rAmelX (test), or a CAF and placebo (control). At three months following reconstructive surgery, the animals were euthanized, and the healing outcomes histologically evaluated.

RESULTS

The test group yielded statistically significantly (p = 0.047) greater formation of cementum with inserting collagen fibers compared with the control group (i.e., 4.38 mm ± 0.36 mm vs. 3.48 mm ± 1.13 mm). Bone formation measured 2.15 mm ± 0.8 mm in the test group and 2.24 mm ± 1.23 mm in the control group, respectively, without a statistically significant difference (p = 0.94).

CONCLUSIONS

The present data have provided for the first-time evidence for the potential of rAmelX to promote regeneration of periodontal ligament and root cementum in recession-type defects, thus warranting further preclinical and clinical testing.

CLINICAL RELEVANCE

The present results set the basis for the potential clinical application of rAmelX in reconstructive periodontal surgery.

Biodegradability of Amniotic Membrane as Potential Scaffold for Periodontal Regeneration

Background In the periodontal regenerative procedure, the membrane used should possess good mechanical stability with suitable resorption time to allow restoration of the lost periodontium. Amniotic membrane (AM) has regenerative potential as a scaffold or barrier membrane due to its various beneficial properties. However, its degradation rate is not clearly reported. Methodology This study aimed to evaluate the resorption capacity of AM and its surface architecture after being subjected to hydrolytic degradation analysis in phosphate buffer solution (PBS). AM was cut into sizes of 10 × 10 mm2 for three replicates. The membranes were weighed before and at different time intervals (days 7, 14, 21, and 28) after immersion in PBS. The degradation rate was determined by the percentage of mean weight loss from the initial weight at different time intervals. The AM surface profile was observed under scanning electron microscopy (SEM) before and after 28 days of immersion. Results The result shows a 92% loss of weight over 28 days with the highest attained in the first seven days (67%), followed by 7%, 17%, and 1% after days 14, 21, and 28, respectively. SEM of the AM surface before the degradation test showed a polygonal shape forming a well-arranged mosaic pattern covered with microvilli. At day 28, the remaining AM appears as porous surface architecture, irregularly arranged fibers, and no microvilli seen. Conclusions This study demonstrated that over four weeks of degradation analysis, AM was not entirely degraded but had lost some of the microstructure. The biodegradability of AM should be further evaluated to elucidate its stability within adequate time parallel with the tissue healing process in periodontal tissue regeneration.

Influence of Occlusal Hypofunction on Alveolar Bone Healing in Rats

The aim of this in vivo study was to investigate the effect of occlusal hypofunction on alveolar bone healing in the absence or presence of an enamel matrix derivative (EMD). A standardized fenestration defect over the root of the mandibular first molar in 15 Wistar rats was created. Occlusal hypofunction was induced by extraction of the antagonist. Regenerative therapy was performed by applying EMD to the fenestration defect. The following three groups were established: (a) normal occlusion without EMD treatment, (b) occlusal hypofunction without EMD treatment, and (c) occlusal hypofunction with EMD treatment. After four weeks, all animals were sacrificed, and histological (hematoxylin and eosin, tartrate-resistant acid phosphatase) as well as immunohistochemical analyses (periostin, osteopontin, osteocalcin) were performed. The occlusal hypofunction group showed delayed bone regeneration compared to the group with normal occlusion. The application of EMD could partially, but not completely, compensate for the inhibitory effects of occlusal hypofunction on bone healing, as evidenced by hematoxylin and eosin and immunohistochemistry for the aforementioned molecules. Our results suggest that normal occlusal loading, but not occlusal hypofunction, is beneficial to alveolar bone healing. Adequate occlusal loading appears to be as advantageous for alveolar bone healing as the regenerative potential of EMD.

Complications and treatment errors related to regenerative periodontal surgery

Regenerative periodontal surgical procedures are an important component in the treatment of advanced periodontitis. They aim to improve the long-term prognosis of teeth that are periodontally compromised by the presence of intrabony and/or furcation defects, resulting biologically in formation of root cementum, periodontal ligament, and alveolar bone and evidenced clinically by reduction of deep pockets to maintainable probing depths and/or improvements of vertical and horizontal furcation depth. Over the last 25 years, substantial clinical evidence has been accumulated to support the value of regenerative procedures in periodontally compromised dentitions. However, treatment success requires close attention to certain factors on the level of the patient, the tooth/defect, and the operator. Ignoring these factors in case selection, treatment planning, and treatment execution will increase the risk of complications that may jeopardize clinical success and may even be considered as treatment errors. Based on the currently available evidence from clinical practice guidelines, treatment algorithms, and on expert opinion, the present article provides an overview on the main factors, which influence the outcomes of regenerative periodontal surgery and gives recommendations on how to prevent complications and treatment errors.

Factors that influence the outcomes of surgical endodontic treatment

Surgical endodontic treatment encompasses a broad spectrum of procedures, amongst which root-end cavity preparation and filling, retrograde root canal treatment and through-and-through endodontic surgery, may be classified under the umbrella term 'Root-end surgery'. This narrative review considers the available data on periapical healing, soft tissue healing, tooth survival and oral health-related quality of life (OHRQoL), following root-end surgery and the factors that affect its outcomes. The pooled periapical healed rate for the studies published up to 2021 was 69% (95% CI: 65%, 73%) but increased to 76% (95% CI: 66%, 86%) when only data from the 2020's studies were analysed. The prognostic factors consistently reported for periapical healing have included: pre-operative periapical lesion with complete loss of buccal plate, quality of root-end preparation, remaining thickness of apical root dentine and restorative status. Soft tissue healing of the reflected flap was found to have a positive association with periapical healing. The survival rates following root-end surgery range from 48% to 93%, with failure of periapical healing associated with root and crown fracture, being the predominant reasons for tooth extraction. The factors influencing impact of root-end surgery on patients' quality of life could not be adequately evaluated due to design flaws in the available studies. In conclusion, if root canal treatment failure due to leakage through cracks, fractures or restoration margin are excluded, the remaining cases may represent localized residual infection and inflammation at the periapex that should be amenable to predictable management with the aid of modern root-end surgery.

Latest Findings of the Regenerative Materials Application in Periodontal and Peri-Implant Surgery: A Scoping Review

Regenerative dentistry represents a therapeutic modern approach involving biomaterials and biologics such as mesenchymal stem cells. The role of regenerative dentistry is promising in all branches of dentistry, especially in periodontology and implantology for the treatment of bony defects around teeth and implants, respectively. Due to the number of different materials that can be used for this purpose, the aim of the present review is to evidence the regenerative properties of different materials both in periodontitis and peri-implantitis as well as to compare their efficacy. Clinical trials, case-control studies, cross-sectional studies, and cohort studies have been considered in this review. The outcome assessed is represented by the regenerative properties of bone grafts, barrier membranes, and biological materials in the treatment of intrabony and furcation defects, peri-implantitis sites, alveolar ridge preservation, and implant site development. Based on the studies included, it can be stated that in the last years regenerative materials in periodontal and peri-implant defects treatments have shown excellent results, thus providing valuable support to surgical therapy. To achieve optimal and predictable results, clinicians should always consider factors like occlusal load control, prevention of microbial contamination, and wound dehiscence. Further evidence is required about the use of enamel matrix derivative in alveolar ridge preservation, as well as of stem cells and bone morphogenetic proteins-2 in furcation defects and peri-implantitis sites. Considering the high amount of research being conducted in this field, further evidence is expected to be obtained soon.

Clinical Outcomes of Dental Implants with Two Different Internal Connection Configurations—A RCT

Background: The aim of the present study was to highlight clinical and radiographical differences among implants sharing the same macro-geometry but with two different prosthodontic connections. Methods: Patients requiring at least 2 implants in the posterior area of the jaw were randomly divided into two groups (Conical (CS) and Internal Hexagonal (IH) connection). At implant surgery (T0), insertion torque, implant stability quotient (ISQ values recorded by resonance frequency analysis, RFA), and soft tissue thickness (STH) were assessed. A 1-abutment/1-time protocol was applied, and the prosthesis was realized following a fully digital workflow. At the 36-month follow-up periapical x-rays were taken. In order to statistically analyse differences among the two groups and the different variables, paired T-test was used. Linear regression analysis was conducted to analyze how marginal bone loss (MBL) was affected by other independent variables. A neural network created to predict the success (good or not good) of the implant itself was implemented. Results: 30 out of 33 patients (14 males, 16 females, mean age: 68.94 ± 13.01 years) (32 CS and 32 IH) were analyzed. No implants failed. Marginal bone loss at the 3-year time-point was 0.33 ± 0.34 mm and 0.43 ± 0.37 mm respectively for CS and IH with a significant difference between the two groups (p = 0.004). The presence of keratinized gingiva (p = 0.034) significantly influenced MBL. Conclusions: Both the implant connections investigated presented optimal clinical outcomes with minimal marginal bone loss; however, CS implants and implants with the presence of a greater width of keratinized tissue presented significantly lower MBL.

Dual peptide-functionalized hydrogels differentially control periodontal cell function and promote tissue regeneration

Restoring the tooth-supporting tissues lost during periodontitis is a significant clinical challenge, despite advances in both biomaterial and cell-based approaches. This study investigated poly(ethylene glycol) (PEG) hydrogels functionalized with integrin-binding peptides RGD and GFOGER for controlling periodontal ligament cell (PDLC) activity and promoting periodontal tissue regeneration. Dual presentation of RGD and GFOGER within PEG hydrogels potentiated two key PDLC functions, alkaline phosphatase (ALP) activity and matrix mineralization, over either peptide alone and could be tuned to differentially promote each function. Hydrogel matrix mineralization, fostered by high concentrations of GFOGER together with RGD, identified a PDLC phenotype with accelerated matrix adhesion formation and expression of cementoblast and osteoblast genes. In contrast, maximizing ALP activity through high RGD and low GFOGER levels resulted in minimal hydrogel mineralization, in part, through altered PDLC pyrophosphate regulation. Transplantation of PDLCs in hydrogels optimized for either outcome promoted cementum formation in rat periodontal defects; however, only hydrogels optimized for in vitro mineralization improved new bone formation. Overall, these results highlight the utility of engineered hydrogel systems for controlling PDLC functions and their promise for promoting periodontal tissue regeneration.

Clinical evaluation and biological understanding of the early step-by-step healing after periodontal microsurgery: A case report with PES analysis comparing initial and 31-day result

Microsurgery has evolved, permitting faster vascularization and healing than macro-interventions, reducing tissue trauma and obtaining precise wound closure. Therefore, this study aimed to detail the initial healing steps after the periodontal microsurgical procedure. A -26 year-old female had a localized recession (anterior lower tooth, recession type1-), with the absence of local keratinized tissue width (KTW) and adjacent gingival thickness (GT)<1 mm. After oral prophylaxis and occlusal adjustments, the pink esthetic score was performed (5 points), followed by the microsurgery procedure. Prior to inserting the subepithelial connective tissue graft (SCTG), the epithelial layer was removed, and the root surface was biomodified. Two days postoperatively, it was possible to observe a white layer from the SCTG in the gingival margin, decreasing after 4 days. In 6 days, the sutures were removed; no graft and volume loss was observed. For 9 days, the volume was the maintenance. Nevertheless, there was a reduction in tissue volume in the facial zone. After 11 and 13 days, an improved healing process was found, whereas, after 16 days, it was possible to report stable tissues, which was confirmed after 31 days, with a significant GR reduction and an increase in KTW and GT. Moreover, the final pink esthetic score (PES) was 9. Microsurgery had a faster healing and predictable outcome, suggesting reduced trauma, which may allow a quicker suture removal without jeopardizing the outcomes.

A Comparative Immunohistochemical Study of Wound Healing after Dental Diode Laser Treatment in the Rat Oral Mucosa

This study aimed to examine the differences in healing patterns using two types of diode laser devices (laser A and laser B) and a steel scalpel for periodontal surgery through histological and immunohistochemical methods. Twenty 12-week-old male rats were assigned to three groups (3, 7, and 14 days). Square-shaped erosion wounds (2 × 2 mm2 diameter) were created on the hard palate of each rat. Two wounds were created using Laser A and a steel scalpel (Bard-Parker No. 15) on the right palate and using Laser B and a steel scalpel on the left side. Rats were sacrificed after 3, 7, and 14 days. Tissues were collected with a margin of 1 mm from the border of the erosional wound of the maxillary hard palate. Histological and immunohistochemical analyses were performed on the tissue samples after 3, 7, and 14 days. The tissue healing pattern and expression of inducible nitric oxide synthase (iNOS) and cluster of differentiation (CD) were observed under a light microscope. Statistical analysis was conducted using the Kruskal−Wallis H test for comparison among the groups (α = 0.05). In comparison to the wounds made with the scalpel, wounds treated with lasers A and B showed delayed healing patterns. There was no significant difference between the two laser treatment groups (p > 0.05). The expression of iNOS and CD68 was not significantly different among the three groups after 3 and 7 days (p > 0.05). On day 14, the groups treated with the dental diode lasers showed higher expression than the group treated with the steel scalpel, but no significant difference was observed (p > 0.05). Laser-induced wounds tended to heal slower than surgical wounds performed using a steel scalpel, but histological and immunohistochemical results showed no significant difference between the dental diode laser and scalpel groups.

Plasma of Argon Treatment of the Implant Surface, Systematic Review of In Vitro Studies

This paper aims to review the evidence of the cellular activity on titanium samples exposed to Plasma of Argon (PoA) treatment. A systematic review was carried out based on the PRISMA statement by searching the Cochrane Library, PubMed, Web of Science, EMBASE and Scopus, up to October 2020. Papers were selected according to PICOS format that is: Population (P): osteoblasts, fibroblasts, gingival cells; Intervention (I): PoA disinfection treatment; Comparison (C): untreated controls; Outcome (O): cell culture; Setting (S): in vitro assays. The quality assessment was performed according to the CRIS Guidelines (Checklist for Reporting In vitro Studies). A total of 661 articles were found, of which 16 were included. The quality assessment revealed an overall poor quality of the studies analyzed. In vitro studies on the potential of PoA showed a potential effect in promoting higher cell adhesion and protein adsorption in the earliest times (hours). This outcome was not so evident when later stages of cell growth on the surfaces were tested and compared to the control groups. Only one study was conducted in vivo on a human sample regarding abutment cleaning. No meta-analysis was conducted because of the variety of experimental settings, mixed methods and different cell lines studied. PoA seems to be effective in promoting cell adhesion and protein adsorption. The duration of this effect remains unclear. Further evidence is required to demonstrate the long-term efficacy of the treatment and to support the use of PoA treatment in clinical practice.

Polymeric Nanotechnologies for the Treatment of Periodontitis: A Chronological Review

Periodontitis is a chronic infectious and inflammatory disease of periodontal tissues estimated to affect 70 - 80 % of all adults. At the same time, periodontium, the site of periodontal pathologies, is an extraordinarily complex plexus of soft and hard tissues, the regeneration of which using even the most advanced forms of tissue engineering continues to be a challenge. Nanotechnologies, meanwhile, have provided exquisite tools for producing biomaterials and pharmaceutical formulations capable of elevating the efficacies of standard pharmacotherapies and surgical approaches to whole new levels. A bibliographic analysis provided here demonstrates a continuously increasing research output of studies on the use of nanotechnologies in the management of periodontal disease, even when they are normalized to the total output of studies on periodontitis. The great majority of biomaterials used to tackle periodontitis, including those that pioneered this interesting field, have been polymeric. In this article, a chronological review of polymeric nanotechnologies for the treatment of periodontitis is provided, focusing on the major conceptual innovations since the late 1990s, when the first nanostructures for the treatment of periodontal diseases were fabricated. In the opening sections, the etiology and pathogenesis of periodontitis and the anatomical and histological characteristics of the periodontium are being described, along with the general clinical manifestations of the disease and the standard means of its therapy. The most prospective chemistries in the design of polymers for these applications are also elaborated. It is concluded that the amount of innovation in this field is on the rise, despite the fact that most studies are focused on the refinement of already established paradigms in tissue engineering rather than on the development of revolutionary new concepts.

Effect Morphology and Surface Treatment of the Abutments of Dental Implants on the Dimension and Health of Peri-Implant Biological Space

Statement of the problem: The gingival configuration around implant abutments is of paramount importance for preserving the underlying marginal bone, and hence for the long-term success of dental implants. Objective: The objective was to study, clinically and histologically, the effects of the change in the morphology of abutments connected to the endosseous implant, and of their surface treatment. In particular, the objective was to ascertain the effect of changing the shape of the transepithelial pillar and the treatment of its surface on the dimensions, quality and health of the components of the peri-implant biological space, such as the dimensions of the epithelial and connective tissues of the biological space, the concentration of inflammatory cells and the density of collagen fibers. Methods: A clinical trial of 10 patients with a totally edentulous maxilla, who had four implants (IPX4010_GALIMPLANT®, Sarria, Spain) inserted in the area of the first and second molars on both sides with computer-guided implant surgery, was conducted with the final purpose of assessing the quality of the peri-implant soft tissue attachment around the transepithelial abutments which were employed (aesthetic machined (RM), aesthetic anodized (RA), slim machined (SM) and slim anodized (SA)). At 8 weeks and following the collection of the samples (removal of the implant-abutment assembly with its surrounding hard and soft tissue) and their processing for subsequent histological and histomorphometric analysis in order to study the dimensions, quality and health of the peri-implant soft tissue area, the variables previously mentioned were determined according to the aims of the study. By using appropriate diameter trephine in order to obtain a useful fringe of soft tissue around the transepithelial pillars, ANOVA and chi-square tests were performed. Results: The SPSS statistical analysis ANOVA results revealed that the machined slim abutments have a better performance considering the variables analyzed with epithelial and connective attachment heights of 1.52 mm and 2.3 mm, respectively, and that connective density (density of collagen fibers) was high at 85.7% of the sample size affected by the design for the slim abutments and 92.9% of the high-density sample size affected by the surface treatment for the machined surface. Conclusions: All variables studied, despite the small sample size, showed the superiority of the slim machined abutment among the four groups.

Periodontal Wound Healing and Regeneration: Insights for Engineering New Therapeutic Approaches

Periodontitis is a widespread inflammatory disease that leads to loss of the tooth supporting periodontal tissues. The few therapies available to regenerate periodontal tissues have high costs and inherent limitations, inspiring the development of new approaches. Studies have shown that periodontal tissues have an inherent capacity for regeneration, driven by multipotent cells residing in the periodontal ligament (PDL). The purpose of this review is to describe the current understanding of the mechanisms driving periodontal wound healing and regeneration that can inform the development of new treatment approaches. The biologic basis underlying established therapies such as guided tissue regeneration (GTR) and growth factor delivery are reviewed, along with examples of biomaterials that have been engineered to improve the effectiveness of these approaches. Emerging therapies such as those targeting Wnt signaling, periodontal cell delivery or recruitment, and tissue engineered scaffolds are described in the context of periodontal wound healing, using key in vivo studies to illustrate the impact these approaches can have on the formation of new cementum, alveolar bone, and PDL. Finally, design principles for engineering new therapies are suggested which build on current knowledge of periodontal wound healing and regeneration.

Effect of photobiomodulation after non-surgical mechanical debridement on cortisol levels in the peri-implant sulcular fluid among patients with peri-implant mucositis

OBJECTIVE

The aim of this was to compare the efficacy of photobiomodulation after non-surgical mechanical debridement (MD) on cortisol levels (CL) in peri-implant sulcular fluid (PISF) among patients with peri-implant mucositis.

METHODS

Patients with peri-implant mucositis were encompassed. All patients underwent non-surgical MD with (test group) and without (control group) a single application of photobiomodulation. Demographic data were collected and PISF was collected. Peri-implant modified plaque index (mPI), modified gingival index (mGI), probing depth and crestal bone loss were measured, and CL in PISF were recorded. All clinical parameters and PISF CL were re-assessed at 4 months of follow-up. p < .05 showed statistical significance.

RESULTS

Seventeen (14 males and 3 females) and 17 (15 males and 2 females) patients with peri-implant mucositis were recruited in test and control groups. The mean age of patients in the test and control groups was 46.1 ± 6.5 and 50.2 ± 2.7 years respectively. At baseline, mPI, mGI, PD and PISF volume and CL in control and test groups were similar. At follow-up, there was a significant reduction in mPI (p < .001), mGI (p < .001), PD (p < .001) and PISF volume (p < .001) and CL (p < .001) in both groups compared with baseline. There was no difference in mPI, mGI, PD and PISF volume and CL in test and control groups at follow-up.

CONCLUSION

In short term, non-surgical MD with photobiomodulation does not offer additional benefits in terms of reducing soft-tissue inflammatory parameters and PISF CL in patients with peri-implant mucositis.

Wound healing in periodontal disease induces macrophage polarization characterized by different arginine-metabolizing enzymes

BACKGROUND AND OBJECTIVE

Macrophages play important roles from the initiation of inflammation to wound healing. Two phenotypes of macrophages, namely pro-inflammatory type macrophages (M1-MΦ) and anti-inflammatory type macrophages (M2-MΦ), have been reported. Two contrasting metabolic enzymes that use arginine as a substrate, inducible nitric oxide synthase (iNOS), and arginase-1 (Arg-1), have been identified as M1-MΦ and M2-MΦ markers, respectively. The purpose of this study was to elucidate the temporal dynamics of the macrophage phenotype during the progression and healing phases of experimental periodontitis in mice.

MATERIAL AND METHODS

A total of 63 C57BL/6J mice were divided into the following 3 groups: control (C), periodontitis (P), and healing (H). To induce periodontitis, a silk ligature was placed around the maxillary bilateral second molars of mice in the periodontitis and healing groups. In the healing group, the ligature was removed 3 days after ligation to induce tissue healing. Maxillary tissue was collected on day 0 for the control group, days 1, 3, 5, and 7 for the periodontitis group (P1, P3, P5, and P7), and days 5 and 7 for the healing group (H5 and H7: 3 days with the ligation + 2 days or 4 days following ligature removal). The left side of the maxilla was subjected to bone structure analysis using micro-computed tomography and gene expression analysis using polymerase chain reaction. On the right side, immunohistochemistry was performed to histopathologically evaluate the localization of macrophages by phenotype in the periodontal tissue.

RESULTS

In the alveolar bone structure analysis, the linear distance of bone height increased significantly in the P5 and P7 groups, whereas bone volume fraction and bone mineral density decreased over time after ligature placement; in the healing group (H5 and H7), these parameters improved significantly compared with the periodontitis group (P5 and P7). Expression of genes encoding pro-inflammatory cytokines and iNOS increased in the periodontitis group, and expression of anti-inflammatory cytokine genes and Arg-1 increased in the healing group. Furthermore, the iNOS/Arg-1 expression ratio increased with ligation, whereas the ratio in the healing groups (H5 and H7) significantly decreased compared with the periodontitis groups (P5 and P7). Immunofluorescence staining revealed a significant increase in the number of iNOS-positive macrophages in the periodontitis group and decrease in the healing group. In contrast, the number of Arg-1-positive macrophages decreased in the periodontitis group and increased in the healing group.

CONCLUSION

The results of the present study suggest that wound healing in periodontal disease induces macrophage polarization from M1-MΦ to M2-MΦ characterized by iNOS and Arg-1.

The Effect of Diabetes Mellitus on IGF Axis and Stem Cell Mediated Regeneration of the Periodontium

Periodontitis and diabetes mellitus (DM) are two of the most common and challenging health problems worldwide and they affect each other mutually and adversely. Current periodontal therapies have unpredictable outcome in diabetic patients. Periodontal tissue engineering is a challenging but promising approach that aims at restoring periodontal tissues using one or all of the following: stem cells, signalling molecules and scaffolds. Mesenchymal stem cells (MSCs) and insulin-like growth factor (IGF) represent ideal examples of stem cells and signalling molecules. This review outlines the most recent updates in characterizing MSCs isolated from diabetics to fully understand why diabetics are more prone to periodontitis that theoretically reflect the impaired regenerative capabilities of their native stem cells. This characterisation is of utmost importance to enhance autologous stem cells based tissue regeneration in diabetic patients using both MSCs and members of IGF axis.

Inflammation and Periodontal Regeneration

Technological innovations in cellular and molecular aspects of tissue engineering --scaffolds, stem cells and 3D printed tissues --have been dramatically increased in the last decade. However, regenerative treatment still has challenges in translation to clinic. This is partly due to failure of addressing an essential element of wound healing, inflammation. It is now well-recognized that inflammation is an active process. This paradigm shift opened up a new avenue of therapeutic approaches called "host-modulation." Host-modulation therapies capable of modulating inflammatory response at multiple levels and mimicking the natural sequence of wound healing offer a new direction and promising clinical translation.

Biological Basis of Periodontal Regeneration

The ultimate goal of periodontal therapy is homeostatic regeneration of lost attachment of alveolar bone and gingival connective tissue to the exposed root surfaces with a fully functional and healthy periodontal ligament that is covered with a healthy epithelium. This goal needs a complete understanding of the biological mechanisms inherent to healing and inflammatory processes.

The Cone Beam Computed Tomography Evaluation of Cortical Bone Plate after Piezocision-Assisted Orthodontic Upper Arch Expansion: A Case Series

Background: The purpose of the study was to evaluate cone beam computed tomography (CBCT) after piezocision-assisted orthodontic maxillary arch expansion. Methods: Forty CBCT images of 20 patients taken before and after treatment were included in the study. The following radiographic parameters were measured: buccal/palatal bone plate thickness measured in three locations, 0.5 mm, 3.5 mm, and 5 mm from the margin of alveolar process; cemento-enamel junction-crest distance (CEJ-C) measured at buccal (CEJ-B) and palatal/lingual (CEJ-P) aspects. Results: After treatment there were insignificant changes in CEJ-C and thickness of buccal/palatal plates for all the dental groups except for incisors and premolars. CEJ-B increased by 1.43 mm on premolars and CEJ-P by 1.65 mm on incisors and by 0.31 mm on premolars. On the incisors, the buccal plate width increased significantly, by 0.2 mm and 0.44 mm at 3.5-mm and 5-mm measurement points. On premolars, the buccal plate width decreased in three measuring points by 0.27 mm, 0.37 mm, and 0.25 mm. Conclusions: Piezocision-assisted orthodontic maxillary arch expansion does not cause evident negative changes of cortical plates except for the premolar region. Therefore, premolars may be at greater risk of buccal plate loss than other teeth.

Apical approach in periodontal reconstructive surgery with enamel matrix derivate and enamel matrix derivate plus bone substitutes: a randomized, controlled clinical trial

Objectives

This parallel, randomized controlled clinical trial evaluated the influence of bone substitutes (BS) on the efficacy of the non-incised papillae surgical approach (NIPSA) with enamel matrix derivate (EMD) in resolving deep, isolated, combined non-contained intrabony and supra-alveolar periodontal defects, preserving the soft tissue.

Material and methods

Twenty-four patients were randomized to treatment with NIPSA and EMD or NIPSA plus EMD and BS. Bleeding on probing (BoP), interproximal clinical attachment level (CAL), interproximal probing depth (PD), recession (REC), location of the tip of the papilla (TP), and width of the keratinized tissue (KT) were evaluated before surgery and at 1 year post-surgery (primary outcomes). Wound closure was assessed at 1 week post‐surgery, and supra‐alveolar attachment gain (SUPRA-AG) was recorded at 1 year post‐surgery.

Results

At 1 week, 87.5% of cases registered complete wound closure and there were no cases of necrosis, without differences between groups (p > .05). At 1 year, all cases showed negative BoP. A significant PD reduction (NIPSA + EMD 8.25 ± 2.70 mm vs. NIPSA + EMD + BS 6.83 ± 0.81 mm) and CAL gain (NIPSA + EMD 8.33 ± 2.74 mm vs. NIPSA + EMD + BS 7.08 ± 2.68 mm) were observed (p < .001) in both groups, without significant between-group differences (p > .05). The residual PD was < 5 mm in all defects (NIPSA + EMD 2.50 ± 0.67 mm vs. NIPSA + EMD + BS 2.67 ± 0.78 mm). Soft tissues were preserved without significant between-group differences (REC: NIPSA + EMD 0.25 ± 0.45 mm vs. NIPSA + EMD + BS 0.17 ± 0.58 mm, p > .05; KT: 0.00 ± 0.43 mm vs. 0.08 ± 0.67 mm, p > .05). There were improvements in the papilla in both groups (TP: NIPSA + EMD 0.33 ± 0.49 mm vs. NIPSA + EMD + BS 0.45 ± 0.52 mm, p > .05), which was only significant in the NIPSA EMD + BS group (0.45 ± 0.52 mm; p < .05). In both groups, CAL gain was recorded in the supra-alveolar component, showing full resolution of the intrabony component of the defect in all cases (SUPRA-AG: NIPSA + EMD 1.83 ± 1.11 mm vs. NIPSA + EMD + BS 2.00 ± 1.76 mm, p > .05).

Conclusions

NIPSA and EMD with or without BS seem to be a valid surgical approach in the treatment of isolated, deep non-contained periodontal defects. In our study, both treatments resulted in significant PD reduction and CAL gain, that extended in the supra-alveolar component, without differences with the use of BS. Both treatments resulted in soft tissue preservation. However, the addition of BS may improve interdental papillary tissue.

Clinical relevance

NIPSA, with or without bone substitutes, resulted in significant periodontal improvement, with soft tissue preservation in isolated, deep non-contained periodontal defects. The application of bone substitutes may provide interproximal soft tissue gain.

Clinical trial registration

Clinicaltrials.gov: NCT04712630.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-021-04256-1.

Personalized and Defect-Specific Antibiotic-Laden Scaffolds for Periodontal Infection Ablation

Periodontitis compromises the integrity and function of tooth-supporting structures. Although therapeutic approaches have been offered, predictable regeneration of periodontal tissues remains intangible, particularly in anatomically complex defects. In this work, personalized and defect-specific antibiotic-laden polymeric scaffolds containing metronidazole (MET), tetracycline (TCH), or their combination (MET/TCH) were created via electrospinning. An initial screening of the synthesized fibers comprising chemo-morphological analyses, cytocompatibility assessment, and antimicrobial validation against periodontopathogens was accomplished to determine the cell-friendly and anti-infective nature of the scaffolds. According to the cytocompatibility and antimicrobial data, the 1:3 MET/TCH formulation was used to obtain three-dimensional defect-specific scaffolds to treat periodontally compromised three-wall osseous defects in rats. Inflammatory cell response and new bone formation were assessed by histology. Micro-computerized tomography was performed to assess bone loss in the furcation area at 2 and 6 weeks post implantation. Chemo-morphological and cell compatibility analyses confirmed the synthesis of cytocompatible antibiotic-laden fibers with antimicrobial action. Importantly, the 1:3 MET/TCH defect-specific scaffolds led to increased new bone formation, lower bone loss, and reduced inflammatory response when compared to antibiotic-free scaffolds. Altogether, our results suggest that the fabrication of defect-specific antibiotic-laden scaffolds holds great potential toward the development of personalized (i.e., patient-specific medication) scaffolds to ablate infection while affording regenerative properties.

Immunohistochemical Evaluation of Periodontal Regeneration Using a Porous Collagen Scaffold

(1) Aim: To immunohistochemically evaluate the effect of a volume-stable collagen scaffold (VCMX) on periodontal regeneration. (2) Methods: In eight beagle dogs, acute two-wall intrabony defects were treated with open flap debridement either with VCMX (test) or without (control). After 12 weeks, eight defects out of four animals were processed for paraffin histology and immunohistochemistry. (3) Results: All defects (four test + four control) revealed periodontal regeneration with cementum and bone formation. VCMX remnants were integrated in bone, periodontal ligament (PDL), and cementum. No differences in immunohistochemical labeling patterns were observed between test and control sites. New bone and cementum were labeled for bone sialoprotein, while the regenerated PDL was labeled for periostin and collagen type 1. Cytokeratin-positive epithelial cell rests of Malassez were detected in 50% of the defects. The regenerated PDL demonstrated a larger blood vessel area at the test (14.48% ± 3.52%) than at control sites (8.04% ± 1.85%, p = 0.0007). The number of blood vessels was higher in the regenerated PDL (test + control) compared to the pristine one (p = 0.012). The cell proliferative index was not statistically significantly different in pristine and regenerated PDL. (4) Conclusions: The data suggest a positive effect of VCMX on angiogenesis and an equally high cell turnover in the regenerated and pristine PDL. This VCMX supported periodontal regeneration in intrabony defects.

Periodontal regeneration: is it still a goal in clinical periodontology?

In the last decades, Periodontal Regeneration has been one of the most discussed topics in Periodontics, attracting the attention of researchers and clinicians. This can be justified by the evident and continuous progress observed in the field, characterized by a better understanding of the biological mechanisms involved, significant improvement of operative and technical principles, and the emergence of a wide range of biomaterials available for this purpose. Together, these aspects put the theme much in evidence in the search for functional and esthetic therapeutic solutions for periodontal tissue destruction. Despite the evident evolution, periodontal regeneration may be challenging and require the clinician to carefully evaluate each case before making a therapeutic decision. With a critical reassessment of the clinical and preclinical literature, the present study aimed to discuss the topic to answer whether Periodontal Regeneration is still a goal in clinical periodontology. The main aspects involved in the probability of success or failure of regenerative approaches were considered. A greater focus was given to intrabony and furcation defects, clinical conditions with greater therapeutic predictability. Aspects such as more appropriate materials/approaches, long-term benefits and their justification for a higher initial cost were discussed for each condition. In general, deep intrabony defects associated with residual pockets and buccal/lingual class II furcation lesions have predictable and clinically relevant results. Careful selection of the case (based on patient and defect characteristics) and excellent maintenance are essential conditions to ensure initial and long-term success.

Evaluation of the Use of Platelet-Rich Fibrin Xenologous Membranes Derived from Bubaline Blood in Canine Periodontal Defects

Periodontal disease is the most common oral disease in dogs. Platelet-rich fibrin (PRF) is widely utilized to facilitate soft and hard tissue healing and has been proposed in periodontal healing in small animal treatment. However, the quality and amount of autologous PRF is compromised in animals with systemic diseases. The present study aimed to evaluate the efficacy of xenologous bubaline blood-derived PRF (bPRF) on periodontal tissue healing in canine periodontal defects. Split-mouth design was employed in twenty dogs diagnosed with periodontal disease. The defects were divided randomly into two groups: the open-flap debridement (OFD)-treated group and the OFD with bPRF (OFD+bPRF) application group. Results demonstrated that gingival index and periodontal probing depth decreased significantly in the OFD+bPRF group compared with those treated with OFD alone. Application of bPRF in periodontal defects also promoted fibrous tissue formation, as confirmed by the marked increase in fibrosis score. bPRF application significantly increased COL1A1 and PDGFB mRNA levels at day 14 compared with the baseline. Taking this evidence together, bPRF provided a favorable therapeutic modality in canine periodontal defects. bPRF could be an alternative biomaterial for the treatment of periodontal defects in dogs.

Principles of Combined Surgical Therapy for the Management of Peri-Implantitis

FOCUSED CLINICAL QUESTION

The purpose of this technical note is to present the principles for combined therapy as well as to illustrate the step-by-step approach of this procedure to efficiently manage peri-implantitis.

SUMMARY

Peri-implantitis is the primary threat that compromises the longevity of dental implants. This entity is regarded as a biofilm-mediated inflammatory condition. As such, the arrestment of disease is conditioned by the elimination of the etiological factor and the clinical resolution of inflammation by eliminating pathogenic pockets. It was suggested that the therapy of peri-implantitis relies upon defect configuration. In this sense, defect configuration is, in part, conditioned by the dimensions of the alveolar bone and implant position. In the clinical basis, it is frequent to identify combined defects exhibiting area(s) where reconstructive therapy is inefficient due to uncontained defect morphology. These situations represent clinical indications for combined therapy.

CONCLUSIONS

This therapeutic modality is based on the combination of reconstructive therapy in the infraosseous defect component and surface modification for the area of the implant within the supracrestal component or outside the reparative potential.