Guided tissue regeneration combined with bone allograft in infrabony defects: Clinical outcomes and assessment of prognostic factors

Feasibility and Preliminary Efficacy of α-Calcium Sulfate Hemihydrate in Socket Preservation: Protocol for a Pilot Randomized Controlled Trial

BACKGROUND

Tooth extraction procedures often lead to bone resorption, which can have adverse effects on the dimensions of the alveolar ridge. Research has shown that socket preservation techniques using bone graft substitutes can effectively minimize early bone loss in such cases. α-calcium sulfate hemihydrate (α-CSH) has garnered significant attention as a potential bone graft material due to its favorable properties, including osteoconductivity, angiogenic potential, and biocompatibility. Considering these facts, we developed a preliminary protocol for applying α-CSH in addressing alveolar bone loss following tooth extraction.

OBJECTIVE

This research's general objective is to evaluate the feasibility and initial effectiveness of α-CSH as bone-inducing graft material for socket preservation after tooth extraction.

METHODS

This preliminary clinical trial will involve 30 fresh extraction sockets from individuals aged 18-35 years. The participants will be divided into 2 groups: one group will receive α-CSH graft material after tooth extraction for socket preservation, while the other group will not receive any graft material. Throughout the study, the participants will be closely monitored for safety measures, which will include clinical examinations, radiographic imaging, and blood tests. Radiographic imaging will be used extensively to assist the progress of bone formation.

RESULTS

The study commenced enrollment in August 2022 and is scheduled to conclude post assessments and analyses by the end of 2023. The results of the study are anticipated to be accessible in late 2024.

CONCLUSIONS

This clinical study represents the initial investigation in humans to assess the feasibility and efficacy of α-CSH in alveolar bone regeneration. We hypothesize that the inclusion of α-CSH can greatly expedite the process of bone formation within fresh sockets, resulting in a swift restoration of bone height without the disadvantages associated with harvesting autogenous bone graft.

TRIAL REGISTRATION

Indonesia Registry Center INA-D02FAHP; https://tinyurl.com/2jnf6n3s.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/49922.

Long-term stability of infrabony defects treated with enamel matrix derivative alone: A retrospective two-centre cohort study

AIM

To assess the long-term stability of attachment gain in infrabony defects (IBDs) 10 years after regenerative treatment with an enamel matrix derivative (EMD) alone.

MATERIALS AND METHODS

Two centres (Frankfurt [F] and Heidelberg [HD]) invited patients for re-examination 120 ± 12 months after regenerative therapy. Re-examination included clinical examination (periodontal probing depths (PPD), vertical clinical attachment level (CAL), plaque index (PlI), gingival index (GI), plaque control record, gingival bleeding index and periodontal risk assessment) and review of patient charts (number of supportive periodontal care [SPC] visits).

RESULTS

Both centres included 52 patients (29 female; median baseline age: 52.0 years; lower/upper quartile: 45.0/58.8 years; eight smokers), each contributing one IBD. Nine teeth were lost. For the remaining 43 teeth, regenerative therapy showed significant CAL gain after 1 year (3.0; 2.0/4.4 mm; p < .001) and 10 years (3.0; 1.5/4.1 mm; p < .001) during which CAL remained stable (-0.5; -1.0/1.0 mm; p = 1.000) after an average SPC of 9 years. Mixed-model regression analyses revealed a positive association of CAL gain from 1 to 10 years with CAL 12 months post operation (logistic: p = .01) as well as a higher probability for CAL loss with an increasing vertical extent of a three-walled defect component (linear: p = .008). Cox proportional hazard analysis showed a positive association between PlI after 12 months and tooth loss (p = .046).

CONCLUSION

Regenerative therapy of IBDs showed stable results over 9 years. CAL gain is associated with CAL after 12 months and decreasing initial defect depth in a three-walled defect morphology. Tooth loss is associated with PlI 12 months post operation.

CLINICAL TRIAL NUMBER

DRKS00021148 (URL: https://drks.de).

Efficacy of Guided Tissue Regeneration Using Frozen Radiation-Sterilized Allogenic Bone Graft as Bone Replacement Graft Compared with Deproteinized Bovine Bone Mineral in the Treatment of Periodontal Intra-Bony Defects: Randomized Controlled Trial

(1) Background: The aim of this study was to compare the clinical and radiographic outcomes of guided tissue regeneration (GTR) using two biomaterials as bone replacement grafts in the treatment of periodontal intra-bony defects. (2) Methods: Using a split-mouth design, 30 periodontal intra-bony defects were treated with either frozen radiation-sterilized allogenic bone grafts (FRSABG tests) or deproteinized bovine bone mineral (DBBM, controls) combined with a bioabsorbable collagen membrane in 15 patients. Clinical attachment level gains (CAL-G), probing pocket depth reductions (PPD-R), and radiographic changes in linear defect fill (LDF) were evaluated 12 months postoperatively. (3) Results: The CAL, PPD, and LDF values improved significantly in both groups 12 months after the surgery. However, in the test group, the PPD-R and LDF values were significantly higher compared to the controls (PPD-R 4.66 mm versus 3.57 mm, p = 0.0429; LDF 5.22 mm versus 4.33, p = 0.0478, respectively). Regression analysis showed that baseline CAL was a significant predictor for PPD-R (p = 0.0434), while the baseline radiographic angle was a predictor for CAL-G (p = 0.0026) and LDF (p = 0.064). (4) Conclusions: Both replacement grafts when used for GTR with a bioabsorbable collagen membrane yielded successful clinical benefits in teeth with deep intra-bony defects 12 months postoperatively. The use of FRSABG significantly enhanced PPD reduction and LDF.

Scaffold Pore Curvature Influences ΜSC Fate through Differential Cellular Organization and YAP/TAZ Activity

Tissue engineering aims to repair, restore, and/or replace tissues in the human body as an alternative to grafts and prostheses. Biomaterial scaffolds can be utilized to provide a three-dimensional microenvironment to facilitate tissue regeneration. Previously, we reported that scaffold pore size influences vascularization and extracellular matrix composition both in vivo and in vitro, to ultimately influence tissue phenotype for regenerating cranial suture and bone tissues, which have markedly different tissue properties despite similar multipotent stem cell populations. To rationally design biomaterials for specific cell and tissue fate specification, it is critical to understand the molecular processes governed by cell-biomaterial interactions, which guide cell fate specification. Building on our previous work, in this report we investigated the hypothesis that scaffold pore curvature, the direct consequence of pore size, modulates the differentiation trajectory of mesenchymal stem cells (MSCs) through alterations in the cytoskeleton. First, we demonstrated that sufficiently small pores facilitate cell clustering in subcutaneous explants cultured in vivo, which we previously reported to demonstrate stem tissue phenotype both in vivo and in vitro. Based on this observation, we cultured cell-scaffold constructs in vitro to assess early time point interactions between cells and the matrix as a function of pore size. We demonstrate that principle curvature directly influences nuclear aspect and cell aggregation in vitro. Scaffold pores with a sufficiently low degree of principle curvature enables cell differentiation; pharmacologic inhibition of actin cytoskeleton polymerization in these scaffolds decreased differentiation, indicating a critical role of the cytoskeleton in transducing cues from the scaffold pore microenvironment to the cell nucleus. We fabricated a macropore model, which allows for three-dimensional confocal imaging and demonstrates that a higher principle curvature facilitates cell aggregation and the formation of a potentially protective niche within scaffold macropores which prevents MSC differentiation and retains their stemness. Sufficiently high principle curvature upregulates yes-associated protein (YAP) phosphorylation while decreased principle curvature downregulates YAP phosphorylation and increases YAP nuclear translocation with subsequent transcriptional activation towards an osteogenic differentiation fate. Finally, we demonstrate that the inhibition of the YAP/TAZ pathway causes a defect in differentiation, while YAP/TAZ activation causes premature differentiation in a curvature-dependent way when modulated by verteporfin (VP) and 1-oleyl-lysophosphatidic acid (LPA), respectively, confirming the critical role of biomaterials-mediated YAP/TAZ signaling in cell differentiation and fate specification. Our data support that the principle curvature of scaffold macropores is a critical design criterion which guides the differentiation trajectory of mesenchymal stem cells’ scaffolds. Biomaterial-mediated regulation of YAP/TAZ may significantly contribute to influencing the regenerative outcomes of biomaterials-based tissue engineering strategies through their specific pore design.

Composite outcome measure (COM) and pocket closure as clinical endpoints following treatment of infra bony defects with Guided tissue regeneration and Open flap debridement

Background

Clinical outcomes of regenerative periodontal therapy has been traditionally assessed using surrogate markers, primarily clinical attachment level (CAL) gain and probing pocket depth (PPD) reduction. This study tried to assess newer clinical endpoints namely pocket closure and composite outcome measure (COM) apart from CAL gain, PPD reduction and gingival recession in patients who underwent guided tissue regeneration (GTR) and compared the same with open flap debridement (OFD) six months post treatment.

Materials and Methods

Records of 58 sites in 48 patients who had undergone GTR (28 sites) and OFD (30 sites) for infrabony defects were evaluated for CAL gain, PPD reduction, change in GR, FMBS, and FMPS at baseline and 6 months after surgery. Pocket closure and COM were used to assess the efficacy of both treatments.

Results

Statistically significant improvements were seen in both the groups except GR from baseline to 6 months. GTR-treated sites showed better improvements with a statistically significant difference in CAL gain after 6 months. Pocket closure and percentage of treatment success and failure in both the groups assessed using a COM were similar and did not differ statistically.

Conclusion

Treatment of infrabony defects with GTR combined with a xenograft offers better CAL gain after 6 months compared to OFD alone and also found that baseline PPD and FMBS were the factors determining pocket closure.

The effect of non-surgical and surgical mechanical root debridement on infrabony defects: a retrospective study

The aim of this retrospective study was to assess the outcomes of non-surgical and surgical mechanical root debridement for the treatment of infrabony defects and explore potential prognostic factors. Treated infrabony defects followed for at least 1 year were selected. All data pertaining to the clinical outcomes were recorded. Multi-level regression analysis and Cox Proportional-Hazards Models were used to assess the immediate (3-6 months) clinical outcomes, survival of the treated teeth, and factors influencing these results. 132 patients were included in the analysis. The analysis showed 1.42 ± 1.71 and 2.23 ± 1.64 mm in pocket depth (PD) reduction, 0.13 ± 1.83 and 0.08 ± 1.76 mm in clinical attachment level (CAL) gain, and 1.29 ± 1.56 and 2.15 ± 1.33 mm increase in gingival recession (REC) for the non-surgical and surgical groups, respectively. The 5-year survival rates were 93% for the non-surgically and 90% for the surgically treated teeth. Several factors affected clinical outcomes and tooth survival. Within its limitations, the treatment of infrabony defects with non-surgical and surgical mechanical root debridement was found to result in moderate but significant PD reduction, nevertheless, this may also be attributable to the resultant REC.

Platelet-Derived Growth Factor-Modulated Guided Tissue Regeneration with a Bioresorbable Membrane in Class III Furcation Defects: A Histometric Study in the Monkey

It was the aim of this study to histometrically evaluate guided tissue regeneration (bioresorbable membrane plus bone mineral) (GTR) with or without platelet-derived growth factor (PDGF) in two different types of class III furcation defects (small keyhole defects and horizonal defects) in monkeys. In six cynomolgus monkeys, two types of class III furcation defects were created and allowed to chronify for 5 months in mandibular first and second molars. After a hygiene program the molars were assigned to GTR group (collagen membrane plus bovine bone mineral), PDGF group (collagen membrane plus bovine bone mineral plus PDGF), or negative control group (flap reposition only). Histologic sections were made after 7 months of healing and descriptive statistics were provided from the histometric parameters. Postoperative healing was uneventful despite marginal membrane exposures in the GTR and PDGF group. Bone regeneration of 23–35% of the original defect area was found in the two treatment groups. In none of the evaluated key parameters (formation of bone, root cementum, connective tissue, or epithelium) differences were detected between GTR and PDGF groups. However, the negative control teeth exhibited better bone regeneration than the treatment groups. The type of class III defect did not influence the regenerative outcome. Within the limits of this study PDGF was not able to enhance the histologic regeneration of class III furcation areas in monkeys compared to bone mineral enhanced GTR treatment regardless of the defect configuration. Membrane exposure during early healing might have influenced these outcomes.

Influence of restorative design on the progression of peri-implant bone loss: A retrospective study

BACKGROUND

Clinical data on the restorative designs affecting the early progression of peri-implantitis are scarce. The aim of this retrospective study was to evaluate the influence of several restorative factors (e.g., restoration emergence angle, and internal screw length/diameter) on the marginal bone loss around implants with peri-implantitis.

METHODS

Implants diagnosed with peri-implantitis having 1- (T1) and 2-year (T2) follow-ups were included. In addition, within 6 months pre-diagnosis (Tb), all cases required to have full documentation in which no evidence of peri-implantitis was not indicated. Changes in marginal bone levels (MBLs) from Tb to T1 and from T1 to T2 were evaluated. The effect of several variables on MBLs changes was assessed via univariate and multivariate generalized estimating equations.

RESULTS

Eighty-three bone-level implants from 65 patients were selected. The mean follow-up before peri-implantitis diagnosis was 99.47 ± 47.93 months. The radiographic mean marginal bone loss was 1.52 ± 1.33 mm (Tb to T1) and 0.58 ± 0.52 mm (T1 to T2). Restoration emergence angle and frequency of maintenance visits significantly affected MBLs from Tb to T1. Besides, 66.3% of the included implants' bone levels were in a zone within 1 mm of the apical end of the internal screw at T1 and remained in this zone during the second follow-up year.

CONCLUSIONS

Significant marginal bone loss occurred in the early post-diagnosis period of peri-implantitis, which could be affected by the restoration emergence angle. Peri-implant MBLs were frequently located in a zone within 1 mm of the apical end of the internal screw.

Reconstructive surgical treatment of isolated deep intrabony defects with guided tissue regeneration using entire papilla preservation technique: A prospective case series

BACKGROUND

The aim of this prospective study is to evaluate the clinical applicability of the entire papilla preservation (EPP) technique in the regenerative treatment of isolated deep intrabony defects using native collagen membrane and bone grafting materials.

METHODS

Fifteen healthy and non-smoker patients (nine males and six females; mean age: 47.73 ± 12.18; range 21 to 63 years) with one isolated deep intrabony defect each (baseline probing depth (PD): 9.03 ± 1.62 mm; clinical attachment level (CAL): 11.16 ± 1.81 mm) were treated with guided tissue regeneration. Surgical access to the defect was provided by a single buccal vertical incision with an interdental tunneling flap. Following the granulation tissue removal, intrabony defect was filled with bone substitutes. A collagen barrier was trimmed and placed under the intact defect-associated papilla with palatal positioning suture. Microsurgical sutures were used for primary closure.

RESULTS

At 1 week, healing of the 15 sites was uneventful. During the study, all sites showed 100% primary closure rate. At 1-year follow-up, an average CAL gain of 5.86 ± 1.28 mm (P < 0.0001), PD reduction of 6.1 ± 1.47 mm (P < 0.0001), and minimal increase in gingival recession of 0.23 ± 0.62 mm (P = 0.168) were observed.

CONCLUSION

This novel surgical technique, that keeps the interdental papilla intact, seems promising to provide optimal biomaterial protection and healing conditions, even when a collagen barrier and bone substitutes are applied.