Interproximal attachment gain: The challenge of periodontal regeneration

Odontogenesis-Empowered Extracellular Vesicles Safeguard Donor-Recipient Stem Cell Interplay to Support Tooth Regeneration

Harnessing the developmental events of mesenchymal condensation to direct postnatal dental stem cell aggregation represents a cutting-edge and promising approach to tooth regeneration. Tooth avulsion is among the most prevalent and serious dental injuries, and odontogenic aggregates assembled by stem cells from human exfoliated deciduous teeth (SHED) have proven effective in revitalizing avulsed teeth after replantation in the clinical trial. However, whether and how SHED aggregates (SA) communicate with recipient components and promote synergistic tissue regeneration to support replanted teeth remains elusive. Here, it is shown that SA-mediated avulsed tooth regeneration involves periodontal restoration and recovery of recipient Gli1+ stem cells, which are mobilized and necessarily contribute to the reestablishment of the tooth-periodontal ligament-bone interface. Mechanistically, the release of extracellular vesicles (EVs) is revealed indispensable for the implanted SA to mobilize recipient Gli1+ cells and regenerate avulsed teeth. Furthermore, SHED aggregates-released EVs (SA-EVs) are featured with odontogenic properties linked to tissue regeneration, which enhance migration, proliferation, and differentiation of Gli1+ cells. Importantly, local application of SA-EVs per se empowers recipient Gli1+ cells and safeguards regeneration of avulsed teeth. Collectively, the findings establish a paradigm in which odontogenesis-featured EVs govern donor-recipient stem cell interplay to achieve tooth regeneration, inspiring cell-free translational regenerative strategies.

A photoresponsive recombinant human amelogenin-loaded hyaluronic acid hydrogel promotes bone regeneration

OBJECTIVES

In order to evaluate the effect of methacrylated hyaluronic acid (HAMA) hydrogels containing the recombinant human amelogenin (rhAm) in vitro and in vivo.

BACKGROUND

The ultimate goal in treating periodontal disease is to control inflammation and achieve regeneration of periodontal tissues. In recent years, methacrylated hyaluronic acid (HAMA) containing recombinant human amyloid protein (rhAm) has been widely used as a new type of biomaterial in tissue engineering and regenerative medicine. However, there is a lack of comprehensive research on the periodontal regeneration effects of this hydrogel. This experiment aims to explore the application of photoresponsive recombinant human amelogenin-loaded hyaluronic acid hydrogel for periodontal tissue regeneration and provide valuable insights into its potential use in this field.

MATERIALS AND METHODS

The effects of rhAm-HAMA hydrogel on the proliferation of human periodontal ligament cells (hPDLCs) were assessed using the CCK-8 kit. The osteogenic differentiation of hPDLCs was evaluated through ALP staining and real-time PCR. Calvarial parietal defects were created in 4-week-old Sprague Dawley rats and implanted with deproteinized bovine bone matrix in different treatment groups. The animals were euthanized after 4 and 8 weeks of healing. The bone volume of the defect was observed by micro-CT and histological analysis.

RESULTS

Stimulating hPDLCs with rhAm-HAMA hydrogel did not significantly affect their proliferation (p > .05). ALP staining and real-time PCR results demonstrated that the rhAm-HAMA group exhibited a significant upregulation of osteoclastic gene expression (p < .05). Micro-CT results revealed a significant increase in mineralized tissue volume fraction (MTV/TV%), trabecular bone number (Tb.N), and mineralized tissue density (MTD) of the bone defect area in the rhAm-HAMA group compared to the other groups (p < .05). The results of hematoxylin and eosin staining and Masson staining at 8 weeks post-surgery further supported the results of the micro-CT.

CONCLUSIONS

The results of this study indicate that rhAm-HAMA hydrogel could effectively promote the osteogenic differentiation of hPDLCs and stabilize bone substitutes in the defects that enhance the bone regeneration in vivo.

Periodontal Health and Its Relationship with Psychological Stress: A Cross-Sectional Study

Background: Studies suggest that chronic psychological stress can lead to oral health deterioration, alter the immune response, and possibly contribute to increased inflammation, which can impact the physiological healing of periodontal tissues. This cross-sectional study seeks to assess and improve clinical understanding regarding the relationship between perceived stress, mindfulness, and periodontal health. Methods: A total of 203 people were analyzed from December 2022 to June 2023. The Periodontal Screening and Recording (PSR) score and Gingival Bleeding Index (GBI), and Plaque Control Record (PCR) of every patient were registered. Subsequently, participants completed the Sheldon Cohen Perceived Stress Scale (PSS) and the Mindfulness Awareness Attention Scale (MAAS) questionnaires. The collected data underwent statistical analysis, encompassing the evaluation of correlations and dependencies. Applying Welch's t-test to assess the relationship between MAAS and the variable indicating the presence or absence of periodontitis, a noteworthy p-value of 0.004265 was obtained. Results: This underscores a significant distinction in MAAS scores between patients affected by periodontitis and those unaffected by the condition. Additionally, Pearson correlations were computed for GBI and perceived stress, PCR and perceived stress, PCR and MAAS. The resulting p-values of 2.2-16, 3.925-8, and 2.468-8, respectively, indicate a statistically significant correlation in each instance. Conclusions: These findings contribute valuable insights into the interconnectedness of these variables, emphasizing the significance of their associations in the study context. Despite the limitations, the findings of this study suggest a significant relationship between psychological stress, mindfulness, and periodontal tissue health. Clinical trials are necessary to incorporate the assessment of a patient's psychological status as a new valuable tool in the management of periodontal health.

Photobiomodulation Therapy in the Management of "Black Triangles" Due to the Absence of the Gingival Interdental Papilla

The absence of an interdental papilla, termed "black triangle," presents a challenge in aesthetic restorations. Photobiomodulation therapy (PBMT) is the non-thermal therapeutic use of light in order to positively modulate biological activity and has shown promise in tissue regeneration, wound healing, and inflammation reduction. This case report introduces a modified PBM protocol known as "hemolasertherapy" aimed at regenerating the gingival interdental papilla to fill the black triangle. In this case report, a 34-year-old female with an unaesthetic black triangle between the maxillary central incisors presented for treatment. Before surgical intervention, our suggested protocol was proposed and explained, detailing potential risks and outcomes. After proper scaling root planning, a suggested protocol with PBM was made. PBM application with a 635 nm wavelength diode laser at four points around the area between the two maxillary central incisors was made: coronal third and apical third of the papilla and mesial and distal of the papilla. Then, bleeding was provoked with a curette inside the sulcus between 11 and 21 (concerned area) by applying pressure on the junctional epithelium and the supracrestal connective tissue. After a few seconds, blood spontaneously filled the "black triangle" coronal to the interdental papilla and was left undisturbed. At this point, PBM was applied again on the same four points already described. The irradiation parameters during all PBM treatments were contact mode and continuous mode, 635 nm wavelength, spot size of 8mm, power of 50 mW, irradiation time on each point of 50 seconds, and energy density of 4.976 J/cm2. After the intervention, the patient was prohibited from smoking, using mouthwash, drinking, and brushing for two hours. The exact same procedure was repeated five and 10 days after the first intervention. Follow-up was made for three months after the intervention. The assessment indicated a minor increase in the papilla height, which was not enough for a complete closure of the "black triangle." However, there was a reduction in the appearance of the black triangle. This case report suggests that PBM if used within our suggested protocol can increase the height of the gingival interdental papilla leading to a more pleasant aesthetic appearance. It is important to note that its effectiveness might be limited to specific conditions. In summary, the presented case report showcased a slight extension of the gingival interdental papilla. Further studies are essential to validate these observations.

Interdental papilla reconstruction: a systematic review

OBJECTIVES

To assess treatment options for the reconstruction of the lost interdental papilla and to evaluate evidence for their efficacy.

METHODS

An electronic search (Medline, Embase and the Cochrane Library Database and OpenGray) and a hand search were carried out to identify all types of studies investigating interdental papilla reconstruction (except for reviews) with a minimum of 3 months follow-up.

RESULTS

Forty-five studies were included in the study including 7 RCTs, 2 cohort studies, 19 case series and 17 case reports. Fifteen studies reported on the use of hyaluronic acid, 6 studies on platelet-rich fibrin, 16 studies on soft tissue grafting, 4 studies on orthodontics and 4 on additional modalities. The most common outcome measures were black triangle dimensions and papillary fill percentage. Meta-analysis was not possible due to the high heterogeneity of the studies.

CONCLUSION

There are various options for interdental papilla reconstruction of which hyaluronic acid injections, PRF, surgical grafting and orthodontics seem to improve outcomes at a minimum 3 months. The use of soft tissue grafting with sub-epithelial connective tissue graft seems to be associated with the most robust evidence for the longer-term reduction of 'black triangles'. There is insufficient evidence to make recommendations to clinicians. Further research is needed in the form of well conducted RCTs with longer follow ups and patient reported outcome measures.

CLINICAL RELEVANCE

Patients frequently complain about the appearance of black triangles and their management options seem unclear. This systematic review provides insight into the available reconstructive options.

Evaluation of advanced platelet-rich fibrin compared to subepithelial connective tissue graft in the surgical management of interdental papilla recession: a randomized controlled trial

OBJECTIVES

The current study aims to compare advanced-platelet-rich fibrin membrane (A-PRF) to connective tissue graft (CTG) using Han and Takei's approach.

MATERIALS AND METHODS

The defective papilla was randomly allocated to either the control group (CTG) or to the experimental group (A-PRF). Papilla height (PH) and percent change in the gingival black triangle (GBT) area were recorded at 1, 3, 6, 9, and 12 months.

RESULTS

Thirty-two deficient IDPs with an initial papilla presence index (PPI) of 2 or 3 were included. At 12 months, the papilla-fill significantly increased in both groups (p < 0.001) without a significant difference between the study groups (p = 0.637). A mean gain in IDP height of 2.25 mm (± 0.97) in the CTG group and 1.86 mm (± 0.7) in the A-PRF group were recorded with a nonsignificant difference. Gingival black triangle fill showed a 57.98% fill in the CTG and 54.65% fill in the A-PRF group, with no statistically significant difference between the groups (0.956). Regarding postoperative pain patients, the CTG group consumed significantly more analgesics than the A-PRF group (11.75 ± 3.51 and 8 ± 3.08, respectively, with p = 0.003).

CONCLUSION

Both CTG and A-PRF were found to be equally effective in increasing deficient IDP height with Han and Takei's surgical technique, with no significant difference. Within the current study's limitations, A-PRF seems to be a viable alternative to CTG in the treatment of GBTs.

CLINICAL RELEVANCE

Multilayered A-PRF membrane can be used as a choice in the augmentation of receded papillae, using Han and Takei's technique.

Modified interproximal tunneling technique with customized sub-epithelial connective tissue graft for gingival papilla reconstruction: report of three cases with a cutback incision on the palatal side

BACKGROUND

Gingival papilla defects, which cause an unpleasant appearance and involve the upper anterior teeth, may be triggered by several factors. Several noninvasive and invasive techniques have been proposed for gingival papilla reconstruction. The combination of interproximal tunneling and customized connective tissue grafts (CTGs) has shown promise in papilla augmentation. However, due to the narrowness and limited blood supply of the gingival papilla, the long-term outcomes of these techniques remain unpredictable. Therefore, achieving tension-free coronal advancement of the interdental papilla and proper placement of the CTG is crucial for successful long-term outcomes and could provide widely applicable methods for papilla augmentation.

CASE REPORT

In this study, we enrolled three patients with gingival papilla defects in the maxillary anterior teeth. For reconstruction, we proposed a modified interproximal tunneling (MIPT) technique combined with a CTG. A crucial modification based on previous studies involved adding a cutback incision to the base of the palatal vertical incision, resulting in tension-free healing. Additionally, the CTG was sutured upright to further enhance the height of the gingiva papilla. To evaluate the efficacy of the MIPT technique, the clinical parameters-including the Jemt papilla index and the distance from the tip of the papilla to the interproximal contact point-were examined using a periodontal probe (UNC15, Hu-friedy) at baseline and 12 months after surgery. All three patients achieved satisfactory papilla reconstruction 12 months after the surgery. These three cases were used to evaluate the efficacy of the MIPT technique combined with the customized CTG. An average increase in the Jemt papilla score from 1.6 to 2.8 and a reduction in the distance from the papilla tip to the contact point of adjacent teeth from 2 mm to 0.08 mm were observed 12 months after surgery.

CONCLUSION

The preliminary results confirmed that this technique holds promise for gingival papilla augmentation between tooth/tooth or tooth/implant.

In-fiber Bragg sensor measurements assess fluid effects on strain in the periodontal space of an ex-vivo swine incisor complex under mechanical loading

The purpose of this study is to determine whether in-fiber Bragg grating (FBG) sensors detect changes within the periodontal ligament (PDL) of ex-vivo swine tooth-PDL-bone complex (TPBC) when manipulating fluid content. Recording strain will allow for a better understanding of the biomechanics of viscoelastic load transfer from the tooth to the PDL during chewing and/or orthodontic tooth movement, as well as replication of these dynamics in regenerated PDL tissues. FBG sensors placed within the PDL of swine incisor teeth were used to measure strain resulting from an intrusive load. Specimens were mounted in a custom platform within an MTS machine and a compressive load was applied at 0.3 mm/s to a depth of 0.5 mm and held for 10 s. Median peak strain and load and median absolute deviation (MAD) were compared: dry vs. saline (n = 19) with bias-corrected bootstrap 95% CI. Dry vs. saline conditions did not statistically differ (median peaks of 5με, 103-105 N) and recorded strains showed high repeatability (MAD of 0.82με, 0.72με, respectively). FBG sensors did not detect the fluid changes in this study, suggesting that the deformation of tissues in the PDL space collectively determine FBG strain in response to tooth loading. The repeatability of measurements demonstrates the potential for FBG sensors to assess the strain in the PDL space of an in vivo swine model.

Growth Factor Delivery Using a Collagen Membrane for Bone Tissue Regeneration

The use of biomaterials and bioactive agents has shown promise in bone defect repair, leading to the development of strategies for bone regeneration. Various artificial membranes, especially collagen membranes (CMs) that are widely used for periodontal therapy and provide an extracellular matrix-simulating environment, play a significant role in promoting bone regeneration. In addition, numerous growth factors (GFs) have been used as clinical applications in regenerative therapy. However, it has been established that the unregulated administration of these factors may not work to their full regenerative potential and could also trigger unfavorable side effects. The utilization of these factors in clinical settings is still restricted due to the lack of effective delivery systems and biomaterial carriers. Hence, considering the efficiency of bone regeneration, both spaces maintained using CMs and GFs can synergistically create successful outcomes in bone tissue engineering. Therefore, recent studies have demonstrated a significant interest in the potential of combining CMs and GFs to effectively promote bone repair. This approach holds great promise and has become a focal point in our research. The purpose of this review is to highlight the role of CMs containing GFs in the regeneration of bone tissue, and to discuss their use in preclinical animal models of regeneration. Additionally, the review addresses potential concerns and suggests future research directions for growth factor therapy in the field of regenerative science.

Vertical soft tissue augmentation to treat implant esthetic complications: A prospective clinical and volumetric case series

INTRODUCTION

Challenging implant esthetic complications are often characterized by implant malpositioning and interproximal attachment loss of the adjacent teeth. However, limited evidence is available on the treatment of these conditions. The aim of this study was to evaluate the clinical, volumetric, and patient-reported outcome following treatment of peri-implant soft tissue dehiscences (PSTDs) exhibiting interproximal attachment loss on adjacent teeth, performed through vertical soft tissue augmentation with implant submersion.

METHODS

Ten subjects with isolated PSTD in the anterior maxilla characterized by adjacent dentition exhibiting interproximal attachment loss were consecutively enrolled and treated with horizontal and vertical soft tissue augmentation, involving crown and abutment removal, two connective tissue grafts, and submerge healing. Clinical outcomes of interest included mean PSTD coverage, mean PSTD reduction, clinical attachment level (CAL) gain at the implant and adjacent sites and soft tissue phenotype modifications at 1 year. Optical scanning was used for assessing volumetric changes. Professional assessment of esthetic outcomes was performed using the Implant Dehiscence coverage Esthetic Score (IDES), while patient-reported esthetic assessment involved a 0-10 visual analogue scale.

RESULTS

The mean PSTD depth reduction and mean PSTD coverage at 1 year were 2.25 mm, and 85.14%, respectively. A mean keratinized tissue width (KTW) gain of 1.15 mm was observed, while the mean gain in mucosal thickness (MT) was 1.58 mm. A mean CAL gain of 1.45 mm was obtained at the interproximal aspect of the adjacent dentition at 1 year. Greater linear dimensional (LD) changes were observed at the midfacial aspect of the implant compared to the interproximal sites. The mean final IDES was 6.90 points, while patient-reported esthetic evaluation was 8.83 points.

CONCLUSIONS

The present study demonstrated that vertical soft tissue augmentation with a submerged healing is an effective treatment approach for the treatment of challenging PSTDs with adjacent dentition exhibiting interproximal attachment loss. This technique can be effective in resolution of esthetic complications in most cases, providing a substantial gain in interproximal attachment levels at the adjacent dentition.

Efficacy of biologics for the treatment of periodontal infrabony defects: An American Academy of Periodontology best evidence systematic review and network meta-analysis

BACKGROUND

A large variety of biomaterials, biologics and membranes have been utilized in the past 40 years for the regenerative treatment of periodontal infrabony defects. Biologic agents have progressively gained popularity among clinicians and are routinely used for periodontal regeneration. In alignment with the goals of the American Academy of Periodontology (AAP) Best Evidence Consensus (BEC) on the use of biologic mediators in contemporary clinical practice, the aim of this sytematic review was to evaluate the effect of biologic agents, specifically autogenous blood-dervied products (ABPs), enamel matrix derivative (EMD) and recombinant human platelet-derived growth factor-BB (rhPDGF-BB), on the regenerative outcomes of infrabony defects.

METHODS

A detailed systematic search was conducted to identify eligible randomized control trials (RCTs) reporting the outcomes of periodontal regenerative therapy using biologics for the treatment of infrabony defects. A frequentist mixed-modeling approach to network meta-analysis (NMA), characterized by the assessment of three individual components for the treatment of an infrabony defect (the bone graft material [BG], the biologic agent, the application of a barrier membrane) was performed to evaluate and compare the relative efficacy of the different components, on the outcomes of different therapeutic modalities of periodontal regeneration.

RESULTS

A total of 153 eligible RCTs were included, with 150 studies contributing to the NMA. The quantitative analysis showed that the addition of biologic agents to bone graft significantly improves the clinical and radiographic outcomes, as compared to BG and flap procedures alone. Barrier membranes enhanced the regenerative outcomes of BG but did not provide further benefits in combination with biologics. The type of BG (autogenous, allogeneic, xenogeneic or alloplastic) and the biologic agent (EMD, platelet-rich fibrin [PRF], platelet-rich plasma [PRP] or rhPDGF-BB) played a significant role on the final outcomes of infrabony defects. Allogeneic and xenogeneic BGs exhibited statistically significantly superior clinical gain than synthetic and autogenous BGs (p < 0.05 in all the comparisons), while rhPDGF-BB and PRF demonstrated significantly higher stability of the gingival margin (p < 0.01) and radiographic bone fill/gain (p < 0.05), together with greater, although not statistically significant, clinical attachment level gain and pocket depth reduction, than EMD and PRP. Overall, rhPDGF-BB exhibited the largest effect size for most parameters, including clinical attachment level gain, pocket depth reduction, less gingival recession and radiographic linear bone gain. Considering the relatively high number of trials presenting an unclear or high risk of bias, the strength of recommendation supporting the use of PRP was judged weak, while the recommendation for EMD, PRF and rhPDGF-BB was deemed in favor.

CONCLUSIONS

Biologics enhance the outcomes of periodontal regenerative therapy. Combination therapies involving BGs + biologics or BGs + barrier membrane demonstrated to be superior to monotherapies. The choice of the type of BG and biologic agent seems to have significant impact on the clinical and radiographic outcomes of infrabony defects.

Periodontal granulation tissue preservation in surgical periodontal disease treatment: a pilot prospective cohort study

Purpose

Methods

Results

Conclusions

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.