Horizontal bone augmentation by means of guided bone regeneration

Optimal submicron roughness for balancing degradation behavior, immune modulation, and microbial adhesion on zinc-based barrier membranes

Metallic zinc (Zn) has been demonstrated to be a promising alternative to barrier membrane materials for guided bone regeneration. Surface roughness significantly affects the properties of degradable Zn-based metals, especially within the Janus micro-environments of tissue regeneration. However, the effects of optimal surface roughness on Zn remain unknown. In this study, pure Zn surfaces were fabricated with three roughness scales: nano (Sa < 0.1 μm), submicron (Sa: 0.5-1.0 μm), and micron (Sa > 1.0 μm). Submicron-scale pure Zn exhibited a moderate degradation rate in simulated body fluids, and no deep corrosion pits appeared on the surface. By contrast, the degradation rate of nano-surface pure Zn decreased significantly, while localized corrosion tended to appear on micron surfaces. In addition, the degradation rate of Zn with different roughness was overall accelerated in artificial saliva, accompanied by varying degradation morphologies. Co-culturing with submicron samples inhibited macrophage polarization to the M1 phenotype. Nano-scale surfaces promoted macrophage polarization towards the M1 phenotype and exhibited significantly reduced antibacterial rates compared to rougher surfaces. These findings demonstrate that submicron-scale pure Zn could be an optimal choice for barrier membrane surfaces.

A Retrospective Study Using a Novel Body-Shift Implant Design with a Novel Alloplastic Particulate Grafting Material in Immediate Extraction Sockets

With resurgence in immediate tooth replacement therapy (ITRT) as a method of preserving both hard and soft tissues for improved aesthetic outcomes, this multicenter, prospective study looked at two novel products and their effect on those outcomes. Thirty-one maxillary single-tooth implants were included, of these 54.8% were central incisors, 25.8% lateral incisors, and 19.4% canines. Three complications were reported; one case nondraining fistula, one case a nonseated provisional restoration, and one case a fractured zirconia abutment. The definitive restorations were delivered between 4 hours and 18 months postimplant placement and all restorations were screw-retained. ITRT is frequently utilized when a tooth to be extracted will be replaced by an implant aiding in preservation of the hard and soft tissue that may be lost due to resorption during healing of the extraction socket. The narrower neck region of the Inverta implant results in thicker crestal bone around the implant, where loading under function occurs. Grafting that area around the implant at placement with EthOss results in more predictable bone stability in the long term.

Impact of Two Flap Advancement Techniques and Periosteal Suturing on Graft Displacement During Guided Bone Regeneration

OBJECTIVES

This preclinical ex vivo porcine study aimed to evaluate the effects of two flap advancement techniques and periosteal suturing (PS) on graft material displacement during primary wound closure in guided bone regeneration (GBR). Secondary objectives included assessing flap advancement and the impact of soft tissue characteristics on graft displacement.

MATERIALS AND METHODS

Standardized two-walled horizontal bone defects were created in second premolar sites of pig hemimandibles. Sites were randomized to using either full-thickness flaps with modified periosteal releasing incisions (MPRI) or combination flaps using the mucosal detachment technique (MDT), both with and without PS. Cone-beam computed tomography was used to measure changes in graft material thickness (GMT) at seven incremental levels (L0-L6) relative to the implant platform, before and after primary wound closure. Keratinized mucosa width (KMW), flap thickness (FT), and flap advancement (FA) were also recorded.

RESULTS

Sixty-eight horizontal bone augmentation procedures were performed on 34 pig hemimandibles, divided into four groups (MDT+PS, MDT-PS, MPRI+PS, MPRI-PS). Mean overall change in GMT at L0 was -24.5% ± 14.0% for MPRI and - 23.0% ± 14.3% for MDT (p ≥ 0.085). PS reduced graft displacement (-14.2% ± 11.5%) compared with no PS (-33.2% ± 16.9%, p < 0.001). FA was 8.3 ± 1.1 mm (MPRI) and 8.3 ± 1.5 mm (MDT). The mean KMW was 6.8 ± 0.9 mm, and FT ranged from 0.8 to 1.6 mm.

CONCLUSIONS

PS significantly reduced graft material displacement during primary wound closure, while flap advancement techniques and soft tissue characteristics had no impact on graft stability. Both surgical techniques provided sufficient flap advancement for primary wound closure.

Construction of bilayer biomimetic periosteum based on SLA-3D printing for bone regeneration

An ideal biomimetic periosteum should have excellent biocompatibility to promote osteoclast adhesion and improve osseointegration, which is significant in promoting bone regeneration. In this work, a bionic artificial periosteum printed by the SLA-3D printing was prepared, consisting of a poly (ethylene glycol) diacrylate (PEGDA)/chitosan/tricalcium phosphate (TCP) fibrous layer and a gelatin methacryloyl (GelMA)/ammonium molybdate (Mo) cambium layer. Distinct surface characteristics were achieved on both sides of the biomimetic periosteum. Among them, the fibrous layer has high mechanical properties and low porosity, which is conducive to preventing the pulling of muscle tissues and the invasion of soft tissues. The cambium layer has a porous structure and bioactive factors that can effectively promote osteogenic differentiation of preosteoblasts. Combined with mild photothermal therapy triggered by NIR light, the biomimetic periosteum could promote bone regeneration at both the chemical and physical levels. This 3D-printed bilayer hydrogel can provide a promising strategy for preparing advanced tissue-engineered periosteum with excellent physical and bone regeneration properties.

Deproteinized Bovine Bone Mineral With Collagen for Anterior Maxillary Ridge Augmentation: A Retrospective Cohort Study

OBJECTIVES

This study aimed to assess the effects of deproteinized bovine bone mineral with collagen (DBBMC) combined with deproteinized bovine bone mineral (DBBM) on facial alveolar bone augmentation in the anterior maxillary region.

MATERIALS AND METHODS

Patients receiving dental implant placement with simultaneous lateral bone augmentation using DBBM (control group) or DBBMC combined with DBBM (test group) were included in the study. The radiographic assessment of facial alveolar bone, such as facial horizontal bone thickness (FHBT), facial vertical bone level (FVBL), and square of facial bone (SFB), was taken by cone beam computed tomography (CBCT). Generalized estimated equation (GEE) was performed to identify influencing factors associated with the contraction in square of facial bone (SFBC).

RESULTS

A total of 164 implants from 164 patients were included in this study. After 6 months post-surgery, the SFBC and the alterations of FHBT and FVBL in the test group were significantly higher than those in the control group (p < 0.05). After 1-2 years after restorations, the SFBC and the alterations of FHBT and FVBL in the test group were significantly lower than those in the control group (p < 0.05). Spearman correlation analysis demonstrated a positive correlation between the alterations of FVBL and FHBT at the implant platform level in the test group (rs = 0.322, p = 0.001; rs = 0.349, p = 0.002). Implant timing of early loading (p = 0.014) and the implant site of the central incisor (p = 0.040) were significantly associated with the SFBC.

CONCLUSIONS

The applications of DBBMC combined with DBBM achieved better facial alveolar bone augmentation in the anterior maxillary region, especially in early implant placement.

Bioceramics for Guided Bone Regeneration: A Multicenter Randomized Controlled Trial

OBJECTIVES

To compare the clinical effectiveness of a novel bioceramic (BC) with a control xenograft (BO) for guided bone regeneration (GBR) performed simultaneously with implant placement.

MATERIALS AND METHODS

This clinical study enrolled patients with insufficient bone volume who required GBR during implant placement to increase bone width using either BC or BO. Outcome measures included a dimensional reduction in buccal bone thickness measured by cone beam computed tomography performed immediately post-surgery and at 6 months postoperatively (ΔHBBT), soft tissue healing at 14 days, 1 month, and 6 months postoperatively, and complications rates. The primary outcome was the change in buccal bone thickness around the implant.

RESULTS

Of the total 152 patients included, 76 from each group received BC and BO treatments. The ΔHBBT in BC and BO groups were -0.276 mm (-0.432, -0.121) and -0.614 mm (-0.769, -0.459) mm, respectively, rejecting the null hypothesis. No significant difference in soft tissue healing was observed between the two groups, with no inflammatory changes in 96.05% and 90.79% of the BC and BO groups, respectively, at 2 weeks postoperatively. However, the BC group exhibited a lower overall complication rate (3.95%), including mild inflammation, poor soft tissue healing, and bone graft extrusion in 3 out of 76 patients.

CONCLUSIONS

Both BC and BO demonstrated favorable outcomes in bone regeneration and soft tissue healing when used for simultaneous implant placement and bone augmentation.

From Waste to Innovation: A Circular Economy Approach for Tissue Engineering by Transforming Human Bone Waste into Novel Collagen Membranes

The aim of the circular economy is to treat waste as a valuable raw material, reintegrating it into the industrial economy and extending the lifecycle of subsequent products. Efforts to reduce the production of hard-to-recycle waste are becoming increasingly important to manufacturers, not only of consumer goods but also of specialized items that are difficult to manufacture, such as medical supplies, which have now become a priority for the European Union. The purpose of the study is to manufacture a novel human-purified type I collagen membrane from bone remnants typically discarded during the processing of cortico-cancellous bones in tissue banks and to evaluate its mechanical properties and effectiveness in regenerating bone-critical mandibular defects in rabbits. To prepare the novel membrane, cortico-cancellous bone chip samples from a local tissue bank were processed to isolate collagen by demineralization under agitation in HCl, cast into a silicone mold, and air-dried at room temperature and UV irradiation. The average thickness of the four batches analyzed by SEM was 37.3 μm. The average value of Young's modulus and tensile strength obtained from the specimens was 2.56 GPa and 65.43 Mpa, respectively. The membrane's efficacy was tested by creating a critical bicortical and bilateral osteoperiosteal defect in rabbit mandibles. The right-side defects were covered with the collagen membrane, while the left-side defects were left untreated as a control. Nine weeks post-surgery, clinical, radiological, and histological analyses demonstrated new bone formation in the treated areas, whereas the control sites showed no bone regeneration. This innovative approach not only contributes to sustainability in healthcare by optimizing biological waste but also exemplifies efficient resource use in line with the circular economy, offering a cost-effective, biocompatible option that could benefit national health systems.

A biodegradable magnesium alloy promotes subperiosteal osteogenesis via interleukin-10-dependent macrophage immunomodulation

In situ bone regeneration and vertical bone augmentation have been huge problems in clinical practice, always imposing a significant economic burden and causing patient suffering. Herein, MgZnYNd magnesium alloy rod implantation in mouse femur resulted in substantial subperiosteal new bone formation, with osteoimmunomodulation playing a pivotal role. Abundant macrophages were attracted to the subperiosteal new bone region and proved to be the most important regulation cells for bone regeneration. Periosteum stripping, macrophage depletion, and interleukin-10 (IL-10) blockade effectively diminished the MgZnYNd alloy-induced subperiosteal osteogenesis. Mechanistically, the degradation products of MgZnYNd alloy promoted M2 macrophage polarization and the secretion of anti-inflammatory cytokine IL-10, which enhanced periosteum-derived stem cells (PDSCs) osteogenesis through the JAK1-STAT3 pathway. An anti-IL-10 neutralizing antibody or STAT3 inhibitor significantly inhibited M2 macrophage-mediated osteogenic differentiation of PDSCs. Transcriptomics and proteomics revealed that periostin is the core regulator of PDSCs osteogenic differentiation. Furthermore, a novel clinical translation application of Mg-induced subperiosteal osteogenesis was developed, demonstrating its ability to preserve the height and width of the alveolar crest in rats and rabbits following tooth extraction. Collectively, these findings unveil a previously undefined role for Mg alloy-induced subperiosteal osteogenesis via macrophage-mediated osteoimmunomodulation, suggesting the therapeutic potential of magnesium alloy in bone regeneration and bone augmentation.

Impact of Implant Design on Outcomes of Simultaneous Guided Bone Regeneration for Dehiscence Defects: A Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis aimed to determine the implications of implant design on the outcomes of simultaneous guided bone regeneration (GBR) to correct dehiscence defects.

METHODS

A structured search strategy was applied to MEDLINE (PubMed), Cochrane Library, and Embase, to identify prospective clinical trials involving implants with simultaneous GBR to correct dehiscence defects. Data regarding implant characteristics, GBR materials, as well as dehiscence defect dimensions at implant placement and surgical re-entry was collected. Meta-analyses were performed to estimate the pooled mean for (1) baseline dehiscence defect dimensions, (2) changes in defect dimensions at re-entry, and (3) prevalence of complete defect resolution.

RESULTS

4298 unique records were identified, of which 21 studies with 680 implants were included. Despite having comparable baseline defect dimensions, greater height gains were achieved by implants with machined collars (MC) than noncollared (NC) implants (4.40 mm, 95% CI [3.70, 5.11] and 3.23 mm, 95% CI [2.72, 3.75] respectively), with significant subgroup differences (P < .01). Specifically, superior outcomes were observed for MC with space-maintaining geometries. However, there were no significant differences in the changes in defect width, prevalence of complete defect resolution, or the prevalence of postsurgical complication rates (P = .15, .54, and .18 respectively).

CONCLUSIONS

The regenerative outcomes of GBR were influenced by the implant design. Space-maintaining machined collars provide a tenting effect that improves vertical bone gain. While additional research is required to ascertain these findings and integrate choices regarding implant design into clinical decision-making, clinicians may consider replicating this effect to enhance treatment outcomes.

Alveolar bone regeneration using a 3D-printed patient-specific resorbable scaffold for dental implant placement: A case report

BACKGROUND

This case report demonstrates the effective clinical application of a 3D-printed, patient-specific polycaprolactone (PCL) resorbable scaffold for staged alveolar bone augmentation.

OBJECTIVE

To evaluate the effectiveness of a 3D-printed PCL scaffold in facilitating alveolar bone regeneration and subsequent dental implant placement.

MATERIALS AND METHODS

A 46-year-old man with a missing tooth (11) underwent staged alveolar bone augmentation using a patient-specific PCL scaffold. Volumetric bone gain and implant stability were assessed. Histological analysis was conducted to evaluate new bone formation and graft integration.

RESULTS

The novel approach resulted in a volumetric bone gain of 364.69 ± 2.53 mm3, sufficient to reconstruct the original alveolar bone contour and permit dental implant placement. Histological analysis showed new bone presence and successful graft integration across all defect zones (coronal, medial, and apical), with continuous new bone formation around and between graft particles. The dental implant achieved primary stability at 35 Ncm-1, indicating the scaffold's effectiveness in promoting bone regeneration and supporting implant therapy. The post-grafting planned implant position deviated overall by 2.4° compared with the initial restoratively driven implant plan pre-bone augmentation surgery. The patient reported low average daily pain during the first 48 h and no pain from Day 3.

CONCLUSIONS

This proof-of-concept underscores the potential of 3D-printed scaffolds in personalized dental reconstruction and alveolar bone regeneration. It marks a significant step forward in integrating additive manufacturing technologies into clinical practice through a scaffold-guided bone regeneration (SGBR) approach. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622000118707p).

Guided bone regeneration at dehiscence comparing synthetic bone substitute versus bovine bone mineral: A multicenter, noninferiority, randomized trial

AIM

To evaluate the efficacy of guided bone regeneration (GBR) for the treatment of peri-implant dehiscence defects using a synthetic bone substitute (SBS) or a deproteinized bovine bone mineral (DBBM) as a bone substitute.

METHODS

Patients with expected dehiscence defects following implant placement were randomized to use either SBS or DBBM together with a bioabsorbable collagen membrane over dehiscenced implant surfaces aimed for GBR. The changes in the bone defect size were measured before the GBR procedure and 6 months after implant placement at the re-entry surgery. Secondary outcomes included peri-implant health outcomes, implant cumulative survival rates, bone level changes, and patient-reported outcomes (PROMs) at prosthesis delivery and 1-year follow-up.

RESULTS

Of the 49 included patients, 24 were treated with SBS and 25 with DBBM. In the SBS group, the defect height (DH) at implant insertion was 5.1 ± 2.6 mm and was reduced at re-entry to 1.3 ± 2.0 mm (74.5%). In the DBBM group, the respective changes in DH were 4.1 ± 1.7 mm and 1.5 ± 1.9 mm (63.4%). These differences were not statistically significant (p = 0.216). The complete defect resolution rate was also comparable in both groups without statistical difference (62.5% of patients (15/24) vs. 44% of patients (11/25)). Overall, the marginal bone levels remained stable during the 1-year follow-up in both groups.

CONCLUSION

The SBS is noninferior to DBBM for simultaneous GBR to implant placement at implant sites with buccal dehiscences in terms of defect resolution and evaluated secondary outcomes (KCT0008393 - this clinical trial was not registered before participant recruitment and randomization).

Higher solubility and lower onset temperature of protein denaturation increase the osteoconductive capacity of collagen membranes: A preclinical in vivo study

OBJECTIVES

Collagen membranes are extensively used for guided bone regeneration procedures, primarily for horizontal bone augmentation. More recently, it has been demonstrated that collagen membranes promote bone regeneration. Present study aimed at assessing if structural modifications of collagen membranes may enhance their osteoconductive capacity.

METHODS

Twenty-four adult Wistar rats were used. Bilateral calvaria defects with a diameter of 5 mm were prepared and covered with prototypes of collagen membranes (P1 or P2). The P1 membrane (positive control) presented a lower onset temperature of protein denaturation and a higher solubility than the P2 membrane (test). The contralateral defects were left uncovered (NC). After 1 and 4 weeks, the animals were euthanized. A microcomputed tomography analysis of the harvested samples was performed within and above the bony defect. Undecalcified ground sections were subjected to light microscopy and morphometric analysis.

RESULTS

Bone formation was observed starting from the circumferential borders of the defects in all groups at 1-week of healing. The foci of ossification were observed at the periosteal and dura mater sites, with signs of collagen membrane mineralization. However, there was no statistically significant difference between the groups. At 4 weeks, remnants of the collagen fibers were embedded in the newly formed bone. In the P2 group, significantly more bone volume, more new bone, and marrow spaces compared to the NC group were observed. Furthermore, the P2 group showed more bone volume ectocranially then the P1 group.

CONCLUSIONS

Bone formation subjacent to a P2 membrane was superior than subjacent to the P1 membrane and significantly better compared to the control. Modifications of the physico-chemical properties may enhance the osteoconductive competence of collagen membranes, supporting bone formation outside the bony defects.

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.

Microarchitectural Study of the Augmented Bone Following a Modified Ridge Splitting Technique: Histological and Micro-Computed Tomography Analyses

Objectives: The aim of this matched prospective cohort study was to examine the microarchitecture of the augmented bone following a modified alveolar ridge splitting procedure and compare it to that of native bone. Methods: In the test group, patients underwent a modified ridge split osteotomy procedure to restore the width of the posterior segment of the mandible. Patients with sufficient bone width for dental implant placement in the posterior region of the mandible following 3-month-long spontaneous healing after tooth removal were included in the control group. In both study groups, bone biopsy samples were harvested and dental implants were placed. Histomorphometry and micro-CT analysis were performed. Results: Altogether, 15 patients were included in this study (7 patients in the test group, with 14 bone core biopsies harvested, and 8 patients in the control group, with 13 bone core biopsies harvested). Percentage bone volume (BV/TV) in the micro-CT analysis (22.088 ± 8.094% and 12.075 ± 4.009% for the test and control group, respectively) showed statistically significant differences between study groups. Conclusions: Based on histological and micro-CT analyses, the modified ridge splitting procedure with autologous bone block harvested from the retromolar area results in a dental implant recipient bone microarchitecture superior to that of the extraction sockets left to heal undisturbed for a 3-month-long healing period.

Does an untreated peri-implant dehiscence defect affect the progression of peri-implantitis?: A preclinical in vivo experimental study

OBJECTIVE

To investigate the early impact of plaque accumulation in a buccal dehiscence defect on peri-implant marginal bone resorption.

MATERIALS AND METHODS

In six male Mongrel dogs, four dental implants were placed in the posterior maxilla on both sides (two implants per side). Based on the group allocation, each implant was randomly assigned to one of the following four groups to decide whether buccal dehiscence defect was prepared and whether silk ligation was applied at 8 weeks post-implant placement for peri-implantitis induction: UC (no defect without ligation); UD (defect without ligation); LC (no defect with ligation); and LD (defect with ligation) groups. Eight weeks after disease induction, the outcomes from radiographic and histologic analyses were statistically analyzed (p < .05).

RESULTS

Based on radiographs, the exposed area of implant threads was smallest in group UC (p < .0083). Based on histology, both the distances from the implant platform to the first bone-to-implant contact point and to the bone crest were significantly longer in the LD group (p < .0083). In the UD group, some spontaneous bone fill occurred from the base of the defect at 8 weeks after implant placement. The apical extension of inflammatory cell infiltrate was significantly more prominent in the LD and LC groups compared to the UC group (p < .0083).

CONCLUSION

Plaque accumulated on the exposed implant surface had a negative impact on maintaining the peri-implant marginal bone level, especially when there was a dehiscence defect around the implant.

Resorbable engineered barrier membranes for oral surgery applications

Population aging, reduced economic capacity, and neglecting the treatments for oral pathologies, are the main causal factors for about 3 billion individuals who are suffering from partial/total edentulism or alveolar bone resorption: thus, the demand for dental implants is increasingly growing. To achieve a good prognosis for implant-supported restorations, adequate peri-implant bone volume is mandatory. The Guided Bone Regeneration (GBR) technique is one of the most applied methods for alveolar bone reconstruction and treatment of peri-implant bone deficiencies. This technique involves the use of different types of membranes in association with some bone substitutes (autologous, homologous, or heterologous). However, time for bone regeneration is often too long and the bone quality is not simply predictable. This study aims at engineering and evaluating the efficacy of modified barrier membranes, enhancing their bioactivity for improved alveolar bone tissue regeneration. We investigated membranes functionalized with chitosan (CS) and chitosan combined with the peptide GBMP1α (CS + GBMP1α), to improve bone growth. OsseoGuard® membranes, derived from bovine Achilles tendon type I collagen crosslinked with formaldehyde, were modified using CS and CS + GBMP1α. The functionalization, carried out with 1-ethyl-3-(3 dimethylaminopropyl)carbodiimide and sulfo-N-Hydroxysuccinimide (EDC/sulfo-NHS), was assessed through FT-IR and XPS analyses. Biological assays were performed by directly seeding human osteoblasts onto the materials to assess cell proliferation, mineralization, gene expression of Secreted Phosphoprotein 1 (SPP1) and Runt-Related Transcription Factor 2 (Runx2), and antibacterial properties. Both CS and CS + GBMP1α functionalizations significantly enhanced human osteoblast proliferation, mineralization, gene expression, and antibacterial activity compared to commercial membranes. The CS + GBMP1α functionalization exhibited superior outcomes in all biological assays. Mechanical tests showed no significant alterations of membrane biomechanical properties post-functionalization. The engineered membranes, especially those functionalized with CS + GBMP1α, are suitable for GBR applications thanks to their ability to enhance osteoblast activity and promote bone tissue regeneration. These findings suggest a potential advancement in the treatment of oral cavity problems requiring bone regeneration.

The Use of Mesenchymal Stromal/Stem Cells (MSC) for Periodontal and Peri-implant Regeneration: Scoping Review

The necessity for regenerating peri-implant and periodontal tissues is increasingly apparent. Periodontal diseases can result in a significant loss of clinical attachment level, and tissue regeneration stands as the ultimate goal of periodontal therapy. With the rise of osseointegration, the prosthetic rehabilitation of missing teeth using dental implants has surged, leading to a frequent need for alveolar bone regeneration around implants. This review assessed studies reporting various sources of mesenchymal stromal/stem cells (MSC) and their potential in regenerating periodontal and peri-implant bone tissue. A search was conducted across seven databases spanning the past decade. Three authors independently screened all identified titles and abstracts for eligibility, generating tables to summarize included studies in animals and humans separately. A total of 55 articles were chosen for final evaluation, showcasing five origins of MSC used in humans and animals for regenerating periodontal tissues and peri-implant bone, using different types of scaffolds. Overall, research from the past decades supports the effectiveness of MSC in promoting periodontal and peri-implant regeneration. However, the impact of MSC on regenerative therapies in humans is still in its initial stages. Future research should optimize MSC application protocols by combining techniques, such as the use of nanomedicine and 3D printing for tissue engineering. Clinical studies should also understand the long-term effects and compare MSC therapies with current treatment modalities. By addressing these areas, the scientific community can ensure that MSC therapies are both safe and effective, ultimately enhancing therapeutic strategies and treatment outcomes in Periodontology and Implantology.

Factors influencing labial bone resorption after implant insertion with simultaneous guided bone regeneration: retrospective cone beam computed tomography study

This retrospective study examined factors influencing labial bone resorption in the anterior maxilla 6 months after implant insertion with simultaneous guided bone regeneration. Involving 79 patients (118 implants), the study measured labial horizontal bone width and vertical dimensions using cone beam computed tomography scans taken immediately after surgery and at 6 months. A generalized linear mixed model analyzed potential influencing factors: age, sex, implant site, timing of placement, buccal bone width at the implant platform level post-surgery, implant connection, and bone defect morphology. Significant bone resorption was noted at 6 months. The statistical analysis revealed that buccal bone width at the implant platform, implant connection, and bone defect morphology significantly impacted labial bone resorption, while patient age, sex, timing of placement, and implant site did not. Implants with a buccal bone width ≥2 mm showed significantly less labial horizontal and vertical bone resorption (horizontal P < 0.001, vertical P = 0.001), and healing abutments reduced resorption compared to cover screws (horizontal P = 0.002, vertical P = 0.034). More significant vertical resorption occurred in non-contained bone defects after guided bone regeneration (P = 0.040).

Does defect configuration affect the outcomes of alveolar ridge preservation? An experimental in vivo study

PURPOSE

The purpose of this study was to compare the bone healing potential of 1-, 2-, and 3-wall defects following alveolar ridge preservation (ARP) treatment, as well as to evaluate the efficacy of ARP as a treatment option for destructive sites.

METHODS

Three groups, characterized by 1-, 2-, and 3-wall defects, were randomly assigned to the maxillary second, third, and fourth premolars in each of 8 beagle dogs. Each defect was created at either the mesial or distal root site of the tooth, which was hemi-sectioned and extracted. The contralateral root was preserved to superimpose with the experimental site for histomorphometric analysis. For each site, either spontaneous healing (SH; control) or ARP (test intervention) was randomly applied. Each group was divided in half and underwent a healing period of either 4 or 12 weeks. The Mann-Whitney U test and Kruskal-Wallis test were used for histomorphometric analyses. Statistical significance was set at P<0.05.

RESULTS

Qualitative analysis revealed a higher percentage of new bone in the apical area compared to the coronal area, regardless of defect type and healing period. In quantitative analysis, the 3-wall defect exhibited a significantly higher percentage of mineralization in the ARP group after 12 weeks of healing (ARP: 61.73%±7.52%; SH: 48.84%±3.06%; P=0.029). An increased percentage of mineralization was observed with a greater number of remaining bony walls, although this finding did not reach statistical significance.

CONCLUSIONS

Within the limitations of this study, ARP treatment for compromised sockets appears to yield a higher percentage of mineralization compared to SH. Although the effectiveness of the remaining bony walls was limited, their presence appeared to improve the percentage of mineralization in ARP treatment.

Bioinspired triple-layered membranes for periodontal guided bone regeneration applications

Barrier membranes have been used for the treatment of alveolar bone loss caused by periodontal diseases or trauma. However, an optimal barrier membrane must satisfy multiple requirements simultaneously, which are challenging to combine into a single material. We herein report the design of a bioinspired membrane consisting of three functional layers. The primary layer is composed of clay nanosheets and chitin, which form a nacre-inspired laminated structure. A calcium phosphate mineral layer is deposited on the inner surface of the nacre-inspired layer, while a poly(lactic acid) layer is coated on the outer surface. The composite membrane integrates good mechanical strength and deformability because of the nacre-inspired structure, facilitating operations during the implant surgery. The mineral layer induces the osteogenic differentiation of bone marrow mesenchymal stem cells and increases the stiffness of the membrane, which is an important factor for the regeneration process. The poly(lactic acid) layer can prevent unwanted mineralization on the outer surface of the membrane in oral environments. Cell experiments reveal that the membrane exhibits good biocompatibility and anti-infiltration capability toward connective tissue/epithelium cells. Furthermore, in vitro analyses show that the membrane does not degrade too fast, allowing enough time for bone regeneration. In vivo experiments prove that the membrane can effectively induce better bone regeneration and higher trabecular bone density in alveolar bone defects. This study demonstrates the potential of this bioinspired triple-layered membrane with hierarchical structures as a promising barrier material for periodontal guided tissue regeneration.

Proteomic Analysis of Human Serum Proteins Adsorbed onto Collagen Barrier Membranes

Collagen barrier membranes are frequently used in guided tissue and bone regeneration. The aim of this study was to analyze the signature of human serum proteins adsorbed onto collagen membranes using a novel protein extraction method combined with mass spectrometry. Native porcine-derived collagen membranes (Geistlich Bio-Gide®, Wolhusen, Switzerland) were exposed to pooled human serum in vitro and, after thorough washing, subjected to protein extraction either in conjunction with protein enrichment or via a conventional surfactant-based method. The extracted proteins were analyzed via liquid chromatography with tandem mass spectrometry. Bioinformatic analysis of global profiling, gene ontology, and functional enrichment of the identified proteins was performed. Overall, a total of 326 adsorbed serum proteins were identified. The enrichment and conventional methods yielded similar numbers of total (315 vs. 309), exclusive (17 vs. 11), and major bone-related proteins (18 vs. 14). Most of the adsorbed proteins (n = 298) were common to both extraction groups and included several growth factors, extracellular matrix (ECM) proteins, cell adhesion molecules, and angiogenesis mediators involved in bone regeneration. Functional analyses revealed significant enrichment of ECM, exosomes, immune response, and cell growth components. Key proteins [transforming growth factor-beta 1 (TGFβ1), insulin-like growth factor binding proteins (IGFBP-5, -6, -7)] were exclusively detected with the enrichment-based method. In summary, native collagen membranes exhibited a high protein adsorption capacity in vitro. While both extraction methods were effective, the enrichment-based method showed distinct advantages in detecting specific bone-related proteins. Therefore, the use of multiple extraction methods is advisable in studies investigating protein adsorption on biomaterials.

Long-term effectiveness of UV functionalised short (≤ 6 mm) dental implants placed in the posterior segments of the atrophied maxilla: controlled case series

This study evaluated long-term effectiveness UV functionalised short implants (≤ 6 mm) placed in the posterior segments of the atrophied maxilla. The study included 47 patients from 2018 to 2023 (aged 27 to 56 years, 24 women and 23 men) without any systemic diseases, with unilateral/bilateral missing teeth and vertical atrophy of the posterior maxillary area. Total installed were 64 short UV-functionalized implants and 62 standard implants over 10 mm in length in segments maxilla with sufficient bone parameters. Clinical, laboratory and cone beam computed tomography (CBCT) methods were used to plan implant therapy. The clinical indices included the following parameters: ISQ, MBL, OHIP-G scale. For short implants, the median ISQ at placement was 62.2 for primary stability and the median ISQ at 5 months was 69.6 ISQ. For standard implant, the mean ISQ at placement was 64.3 ISQ, and ISQ after 5 months was 71.6 ISQ. After 6 months mean MBL short implants 0.87 mm, after 1 year 1.13 mm, after 5 years was 1.48 mm. After 6 months mean MBL standard implants 0.84 mm, after 1 year 1.24 mm, after 5 years was 1.58 mm. Mean OHIP-G scores-patients satisfaction with the implant at 4.8 ± 0.3, satisfaction with the operation 4.6 ± 0.4; satisfaction with prosthetics 4.7 ± 0.5. Cumulative success rate 5 years short implants was 96.7%, standard implants was 97.4%, and prosthesis cumulative survival rate was 97.2%. Short ultraviolet functionalized implants used in the posterior resorbed segment of maxilla have been shown to be a reliable alternative to sinus lift, demonstrating fewer complications, reduction in the number of additional surgical interventions and showed satisfactory long-term survival.

Introduction and overview on autogenous Platelet concentrates

This special issue on autologous platelet concentrates (APCs) provides clinicians with an overview on the current understanding of the use of these biomaterials for soft and hard-tissue regeneration. The included papers summarize scientific evidence and the clinical findings, presented in simple tables that outline potential benefits including Patient Reported Outcome Measures (PROMs). This approach enables clinicians to assess clinical relevance and researchers to identify significant gaps in the literature. The first part provides a comprehensive summary of the basic science surrounding APC, with particular focus on their preparation methods. Clear recommendations are outlined, which are crucial for obtaining high-quality APCs, alongside an exploration of how APCs may influence both soft and hard tissue healing processes. Part 2 delves into the clinical evidence for the potential benefits of APCs across a range of applications: alveolar ridge preservation, sinus floor elevation, periodontal plastic surgery, guided tissue regeneration, guided bone regeneration, the healing of Medication-Related Osteonecrosis of the Jaw (MRONJ), and endodontic surgery. In the part 3, the discussion turns to the effects of APCs on the healing of extra-oral wounds, including diabetic foot ulcers, venous leg ulcers, pressure injuries, burns, and more. For those clinicians persuaded by the evidence, the fourth section offers a detailed, step-by-step flowchart for each treatment modality, providing a clear guide for clinical application.

The influence of bone block graft position on bone dimensional changes in staged onlay horizontal ridge augmentation: A 6-month retrospective cohort study

OBJECTIVES

To analyze changes in bone dimensions and their modulating factor in bone dimensions 6 months after horizontal ridge augmentation using autogenous bone grafts.

MATERIALS AND METHODS

Thirty-eight patients with horizontally atrophic alveolar ridges of a single edentulous tooth at the maxillary anterior site were divided into two groups based on the fixation position of the bone block during ridge augmentation surgery (H0, vertical distance from the upper edge of the bone block to the alveolar crest). Patients were classified into a crestal level (CL) group if H0 ≤ 1 mm and a sub-crestal level (SCL) group if H0 > 1 mm. The width and height of the alveolar ridge were recorded using CBCT both before and 6 months after the augmentation procedure.

RESULTS

The CL group comprised 20 patients with 23 implants, whereas the SCL group comprised 18 patients with 22 implants. All the augmentation sites exhibited vertical bone resorption. Vertical bone resorption in the SCL group (1.94 ± 2.11 mm) was significantly higher than that of the CL group (0.61 ± 0.64 mm). The SCL group showed significantly lower horizontal bone gain than the CL group (SCL: 1.02 ± 2.30 mm; CL: 3.19 ± 3.17 mm) at the cervical level. Peri-implant marginal bone loss increased significantly in the SCL group (1.00 ± 2.71 mm) compared to the CL group (0.64 ± 0.40 mm).

CONCLUSION

The bone height decreased after horizontal ridge augmentation using autogenous onlay grafting. The fixation position of the bone block was a modulating factor. The SCL group showed more vertical bone loss, less horizontal bone gain 6 months after surgery, and more marginal bone loss after restoration.

Engineering a microparticle-loaded rough membrane for guided bone regeneration modulating osteoblast response without inducing inflammation

Guided bone regeneration (GBR) is a widely used procedure that prevents the fast in-growth of soft tissues into bone defect. Among the different types of membranes, the use of collagen membranes is the gold standard. However, these membranes are implanted in tissue location where a severe acute inflammation will occur and can be negatively affected. The aim of this study was to develop a collagen-based membrane for GBR that incorporated alginate-hydroxyapatite microparticles. Membranes were manufactured using collagen type I and gelatin and alginate-hydroxyapatite microparticles. Membranes were assessed in terms of topography by scanning electron microscopy and confocal microscopy; stability by swelling after an overnight incubation in saline and enzymatic degradation against collagenase and mechanical properties by tensile tests. Furthermore, the biological response was assessed with SaOs-2 cells and THP-1 macrophages to determine alkaline phosphatase activity and inflammatory cytokine release. Our results showed that the incorporation of different percentages of these microparticles could induce changes in the surface topography. When the biological response was analyzed, either membranes were not cytotoxic to THP-1 macrophages or to SaOs-2 cells and they did not induce the release of pro-inflammatory cytokines. However, the different surface topographies did not induce changes in the macrophage morphology and the release of pro- and anti-inflammatory cytokines, suggesting that the effect of surface roughness on macrophage behavior could be dependent on other factors such as substrate stiffness and composition. Collagen-gelatin membranes with embedded alginate-hydroxyapatite microparticles increased ALP activity, suggesting a positive effect of them on bone regeneration, remaining unaffected the release of pro- and anti-inflammatory cytokines.

Survival analysis of dental implants placed in horizontally severely resorbed maxillae after reconstruction with xenogeneic graft: a case series

PURPOSE

To evaluate the survival rates of dental implants with a hybrid macrostructure and the surface biomimetically coated with nanohydroxyapatite, placed in horizontally atrophic maxillae previously submitted to the guided bone regeneration (GBR) procedure, associated with the use of a deproteinized bovine bone graft (DBB).

METHODS

Twenty-five patients who received 196 implants were involved in this study. First, these patients were submitted to GBR procedures and maxillary sinus lift, where DBB was used as the grafting material. The dental implants were placed after a minimum period of 6 months of the grafting procedures. The patients were followed up every six months and clinical/radiographic examinations were performed to assess the implants, using the following indicators as a reference: (1) Absence of mobility; (2) Absence of pain. Data about the age, surgery time, smoking status, implant size, and time between the grafting procedure and implant placement were correlated with implant failures.

RESULTS

Twelve implants failed, generating a survival rate of 94.23%. None of the variables analysed correlated with the implant failures.

CONCLUSION

Implants with a hybrid macrostructure and surface biomimetically coated with nanohydroxyapatite present good survival rates in horizontally atrophic maxillae grafted with DBB.

A narrative review on the use of autologous platelet concentrates during alveolar bone augmentation: Horizontal (simultaneous/staged) & vertical (simultaneous/staged)

This review aimed to answer the general question of whether autologous platelet concentrates (APCs, an autologous blood-derivative) can improve the outcome of alveolar bone augmentation. Three clinical scenarios were assessed: horizontal/vertical bone augmentation in combination with implant placement (simultaneous approach), horizontal bone augmentation in a staged approach, and vertical bone augmentation in a staged approach. An electronic literature search strategy was conducted for each review from the outset to July 1st, 2023. The titles and abstracts (when available) of all identified studies were screened and imported into a database. If articles appeared to meet the inclusion criteria or their title and abstract had insufficient data, the full text was obtained to make the final decision. All studies that met the inclusion criteria underwent data extraction. Moreover, the references of the identified papers were screened for additional studies. After title and abstract screening and selection criteria application, 14 clinical studies were included for the qualitative analysis: seven for horizontal/vertical bone augmentation in a simultaneous approach, five for horizontal bone augmentation in a staged approach, and two for vertical bone augmentation in a staged approach. There is scarce literature regarding the added value of APCs in bone augmentation, and most studies had small sample sizes, a lack of standardized protocols, and different outcome variables, which makes comparisons between studies difficult. Out of the 14 studies, four were well-designed randomized clinical trials, where we could find better results for the APCs groups. Most studies, particularly comparative and well-designed studies, demonstrated beneficial and promising results of using APCs in alveolar bone augmentation. However, before high-level evidence-based conclusions can be drawn, more randomized clinical trials must compare the benefits of adding APCs to the gold-standard approach.

Improved new bone formation capacity of hyaluronic acid-bone substitute compound in rat calvarial critical size defect

BACKGROUND

Bone loss of residual alveolar ridges is a great challenge in the field of dental implantology. Deproteinized bovine bone mineral (DBBM) is commonly used for bone regeneration, however, it is loose and difficult to handle in clinical practice. Hyaluronic acid (HA) shows viscoelasticity, permeability and excellent biocompatibility. The aim of this study is to evaluate whether high-molecular-weight (MW) HA combined with DBBM could promote new bone formation in rat calvarial critical size defects (CSDs).

MATERIALS AND METHODS

Rat calvarial CSDs (5 mm in diameter) were created. Rats (n = 45) were randomly divided into 3 groups: HA-DBBM compound grafting group, DBBM particles only grafting group and no graft group. Defect healing was assessed by hematoxylin-eosin staining and histomorphometry 2, 4 and 8 weeks postop, followed by Micro-CT scanning 8 weeks postop. Statistical analyses were performed by ANOVA followed by Tukey's post hoc test with P < 0.05 indicating statistical significance.

RESULTS

All rats survived after surgery. Histomorphometric evaluation revealed that at 2, 4 and 8 weeks postop, the percentage of newly formed bone was significantly greater in HA-DBBM compound grafting group than in the other two groups. Consistently, Micro-CT assessment revealed significantly more trabecular bone (BV/TV and Tb.N) in HA-DBBM compound group than in the other two groups, respectively (P < 0.05). Moreover, the trabecular bone was significantly more continuous (Tb.Pf) in HA-DBBM compound group than in the other two groups, respectively (P < 0.05).

CONCLUSION

HA not only significantly promoted new bone formation in rats calvarial CSDs but also improved the handling ability of DBBM.

A digital in situ bone augmentation workflow for reconstructing the alveolar ridge outline using a modified shell technique

The traditional shell technique is a practical method for augmenting horizontal and vertical alveolar bone defects. However, it has drawbacks, including increased morbidity in the donor site and imprecise harvesting of bone grafts. Instead of using a second surgical site, root areas at the defect site could be the in situ donor site. A digitally designed bone harvest guide was used for an in situ bone augmentation workflow, and the modified shell technique was planned and executed in the root area. This technique offered a controllable procedure which might enhance bone augmentation.

Collagen-Based Medical Devices for Regenerative Medicine and Tissue Engineering

Assisted reproductive technologies are key to solving the problems of aging and organ defects. Collagen is compatible with living tissues and has many different chemical properties; it has great potential for use in reproductive medicine and the engineering of reproductive tissues. It is a natural substance that has been used a lot in science and medicine. Collagen is a substance that can be obtained from many different animals. It can be made naturally or created using scientific methods. Using pure collagen has some drawbacks regarding its physical and chemical characteristics. Because of this, when collagen is processed in various ways, it can better meet the specific needs as a material for repairing tissues. In simpler terms, collagen can be used to help regenerate bones, cartilage, and skin. It can also be used in cardiovascular repair and other areas. There are different ways to process collagen, such as cross-linking it, making it more structured, adding minerals to it, or using it as a carrier for other substances. All of these methods help advance the field of tissue engineering. This review summarizes and discusses the current progress of collagen-based materials for reproductive medicine.

Randomized split-mouth clinical trial comparing osteoblastic activity and osteogenic potential of autogenous particle harvesting during implant surgery without irrigation and with irrigation

OBJECTIVE

To compare the osteoblastic activity and osteogenic potential of autogenous particle harvesting during implant surgery using low-speed drilling without irrigation and high-speed drilling with irrigation.

MATERIALS AND METHODS

Thirty patients with bilateral missing teeth of 3.6 and 4.6 were randomized into two groups (Group 1: low-speed drilling without irrigation and Group 2: high-speed drilling with irrigation) and 60 single dental implants were placed. The temperature at the tip of each drill was recorded and the harvested bone was weighed; particle size and Ca and P levels were also analyzed. After osteoblast culture, cell viability, cell cycle assay, cell migration, vascular endothelial growth factor (VEGF) concentration, and mineralized nodule formation were assessed.

RESULTS

Although the temperature of the drills was slightly higher in Group 1, no statistically significant differences were observed (p ≤ 0.05); however, the amount of harvested bone was higher (p < 0.001) and the size of the particles was higher (p = 0.019). In relation to osteoblastic activity and osteogenic potential, higher cell proliferation, higher number of cells in G2/M and S phases, higher cell migration capacity, higher VEGF concentration, and higher amount of mineralized nodule formation were observed in Group 1.

CONCLUSIONS

Low-speed drilling without irrigation does not result in a significant increase in bone temperature compared to conventional drilling. However, a greater amount of bone is obtained; in addition, osteoblastic activity and osteogenic potential are higher with this technique, but further clinical studies are necessary.

Autologous bone harvested during implant bed preparation: A randomized clinical trial comparing high-speed drilling with irrigation versus low-speed drilling without irrigation

OBJECTIVE

To compare collected bone weight and the frequency of autologous bone harvesting from the flutes of surgical drills used for implant bed preparation using two different drilling techniques. A comparative evaluation of radiographic bone density and bone quality was also made.

MATERIALS AND METHODS

A randomized clinical trial was made of 66 dental implants in patients with a single posterior edentulous site. The compared drilling techniques were high-speed drilling with irrigation (control group) and low-speed drilling without irrigation (test group). The bone collected in both groups was dried and weighed with a precise electronic balance. The frequency of harvesting was calculated. The median radiographic bone density of each implant site was measured using cone-beam computed tomography (CBCT) pixel values. Patient sex, age, implant position and dimensions, as well as the last drill diameter were analyzed as independent variables. The level of significance was 5%.

RESULTS

The harvesting of bone chips from drill flutes proved possible in 51.5% of the procedures in the control group and in 100% in the test group (p < 0.001). There were also statistically significant differences in bone weight between the control group (6.7 ± 10.6 mg) and the test group (41.9 ± 30.3 mg) (p < 0.001). The CBCT pixel values were directly correlated with the collected bone weight in both groups. The median radiographic bone density, arch and last drill diameter were significantly associated with harvesting bone frequency and collected bone weight (p < 0.05).

CONCLUSIONS

Our findings suggest that the frequency and weight of autologous bone harvested from drills are greater with low-speed drilling without irrigation than with high-speed drilling with irrigation. Radiographic bone density, arch and last drill diameter also significantly influenced the harvesting outcomes.

Effect of Membrane Fixation and the Graft Combinations on Horizontal Bone Regeneration: Radiographic and Histologic Outcomes in a Canine Model

The aim of this study was to determine the effect of membrane fixation and combinations of bone substitute materials and barrier membranes on horizontal bone regeneration in peri-implant defects. Eight mongrel dogs underwent chronic buccal peri-implant dehiscence defects creation and were randomized into 4 groups: (a) deproteinized bovine bone mineral 1 (DBBM1) with a native collagen membrane (CM) (BB group, positive control group), (b) DBBM1 with native CM and 2 fixation pins (BBP group), (c) DBBM2 with a cross-linked CM (XC group), and (d) DBBM2 with cross-linked CM and 2 fixation pins (XCP group). Following 16 weeks of healing, tissues were radiographically and histomorphometrically analyzed. The total augmented area was significantly larger in the BBP, XC, and XCP groups compared to the BB group (4.27 ± 3.21, 7.17 ± 7.23, and 6.91 ± 5.45 mm2 versus 1.35 ± 1.28 mm2, respectively; P = 0.022). No significant difference for the augmented tissue thickness was observed among the 4 groups. The augmented tissue thickness measured at 3 mm below the implant shoulder was higher in BBP, XC, and XCP than that in BB (2.43 ± 1.53, 2.62 ± 1.80, and 3.18 ± 1.96 mm versus 0.80 ± 0.90 mm, respectively), trending toward significance (P = 0.052). DBBM2 and a cross-linked CM were significantly more favorable for horizontal bone regeneration compared to DBBM1 and a native CM. However, when DBBM1 and a native CM were secured with fixation pins, outcomes were similar. The addition of pins did not lead to more favorable outcomes when a cross-linked CM was used.

In vivo experimental study comparing alveolar ridge preservation versus guided bone regeneration after unassisted socket healing at intact and damaged sites in narrow alveolar ridges

BACKGROUND

To compare bone regeneration and dimensional alteration of alveolar ridge at intact and damaged extraction sockets after alveolar ridge preservation (ARP) and implant placement versus unassisted socket healing followed by guided bone regeneration (GBR) with simultaneous implant placement.

METHODS

In 6 beagle dogs, 3 types of extraction sockets in the mandible were created: (1) intact sockets, (2) 1-wall defect sockets and (3) 2-wall defect sockets. The sockets were allocated to undergo either (1) ARP and implant placement 8 weeks later (ARP group) or (2) GBR with simultaneous implant placement after 8 weeks of unassisted socket healing (GBR group). After an additional healing period of 8 weeks, bone regeneration and dimensional changes were evaluated radiographically and histologically.

RESULTS

GBR showed superior bone formation and greater bone gains compared to ARP, regardless of the initial extraction-socket configuration. Although ARP maintained the preexisting alveolar ridge dimensions, peri-implant bone defects were still detected at 8 weeks of follow-up. Histomorphometric analyses confirmed that GBR increased dimensions of the alveolar ridge compared to baseline, and the augmentation and bone regeneration were greater with GBR than with ARP.

CONCLUSION

Early implant placement with ARP can mitigate alveolar ridge changes in the narrow alveolar ridge. However, early implant placement with simultaneous GBR creates the conditions for enhanced bone regeneration around the implant and greater ridge augmentation compared to ARP, irrespective of the extraction-socket configuration.

Performance of a multiphase bioactive socket plug with a barrier function for alveolar ridge preservation

The natural healing process of extraction socket and traditional socket plug material could not prevent buccal bone wall resorption and down growth of epithelium from the socket orifice. A multiphase bioactive socket plug (BP) is designed to overcome the natural healing process by maintaining the three-dimensional (3D) volume of extraction sockets, particularly in sockets with wall defects, and later provide sufficient alveolar bone volume for implant placement. The study aimed to fabricate and evaluate the physical, chemical, and biological performance of BPin vitro. The BP was fabricated through freeze-drying and layer-by-layer assembly, comprised of a base serving as a scaffold, a central portion for promoting bone regeneration, an upper buccal portion for maintaining alveolar socket dimension with a covering collagen membrane (Memb) on the top and upper buccal surface to prevent soft tissue infiltration. The BP as the experimental group and a pure collagen plug (CP) as the control group were investigated and compared. Radiograph, scanning electron microscopy, and energy-dispersive spectroscopy mapping confirmed that the four-part BP was successfully assembled and fabricated. Swelling rate analysis indicated that BP, CP, and Memb reached swelling equilibrium within 1 hour. BP exhibited a high remaining weight percentage in collagenase solution (68.81 ± 2.21% on day 90) and sustained calcium ion release, reaching the maximum 0.13 ± 0.04 mmol l-1on day 14. In biological assays, BP exhibited excellent cell proliferation (The OD value increased from 0.02 on day 1 to 0.23 on day 21.). The BP group exhibited higher alkaline phosphatase activity and osteocalcin content than the CP group within 21 days. Memb and BP exhibited outstanding barrier function, as evidenced by Hematoxylin and eosin staining. In summary, the multiphase bioactive socket plug represents a promising scaffold for alveolar ridge preservation application.

Profilometric, esthetic, and patient-reported outcomes of the L-shape technique combined with delayed connective tissue grafting in the maxillary anterior region: A 3-year case series study

OBJECTIVE

To evaluate the profilometric, esthetic, and patient-reported outcomes of peri-implant tissues in the maxillary anterior esthetic zone following guided bone regeneration (GBR) using the L-shape technique combined with delayed connective tissue grafting (CTG).

MATERIALS AND METHODS

Profilometric and pink esthetic score (PES) measurements were performed at the time of implant surgery with GBR (T0) and at the 1- (T1), 2- (T2), and 3-year (T3) follow-up. Patient-reported outcomes were also assessed using the Oral Health Impact Profile-14 (OHIP-14) questionnaire. Statistical analysis over 3 years of follow-up assessed changes at time points (T0, T1, T2, and T3) and time periods (T0-T1, T0-T2, and T0-T3) using the Wilcoxon signed-rank test.

RESULTS

A total of 12 patients (57.5 ± 12.3 years) were included in this study. The mean profilometric change in peri-implant tissues over the 3-year follow-up period was 3.49 ± 1.11 mm, and the buccal contours were not significantly different between the comparison periods. The PES remained stable, while all OHIP-14 domain scores improved significantly.

CONCLUSION

Simultaneous implant placement and GBR using the L-shape technique combined with delayed CTG in the maxillary anterior region provides stable buccal profiles and consistent esthetics and improves patient-reported quality of life over a 3-year period.

CLINICAL SIGNIFICANCE

This study demonstrated that GBR using the L-shape technique combined with delayed CTG in the maxillary anterior region improved the buccal profile, esthetics, and patient-reported quality of life.

Comparison of histologic and radiographic changes of sockets grafted with LPRF and sockets without intervention after tooth extraction

OBJECTIVES

After tooth extraction, marked resorption occurs in extraction socket walls, leading to functional and esthetic problems in that area. One of the methods introduced to reduce this resorption is the use of platelet derivatives. This study aimed to evaluate the effects of leukocyte and platelet-rich fibrin (L-PRF) on the changes following tooth extraction.

MATERIALS AND METHODS

The participants were 24 patients who needed to replace at least one single-rooted tooth with an implant. They were randomly divided into test and control groups. After the tooth extraction, the sockets in the test group received LPRF clots, while in the control group, the sockets were left free of any interventions. CBCT scans were obtained from the extraction site both immediately after the tooth extraction and 8 weeks later. The histologic biopsy was also obtained while the implant site was being prepared 8 weeks after the extraction.

RESULTS

The average vertical bone loss in the buccal crest was not significantly different between the two groups (1.67 ± 1.67 in the test group and 2.3 ± 1.36 in the control group; mean difference =  - 0.36, 95% CI: - 1.65-0.93, p-value = 0.57). Nor was the difference in resorption of the palatal wall (mean difference =  - 0.19, 95% CI: - 1.51.12, p-value = 0.76). The mean ridge width resorption in 25% of the coronal aspect of sockets was also measured in the test (1.30 ± 0.66) and control group (0.58 ± 0.95) (mean difference = 0.73, 95% CI: 0.03-1.42, p-value = 0.04). The new bone formation in histologic view was not statistically different between groups (p-value = 0.15).

CONCLUSION

The LPRF neither reduces the rate of ridge resorption in vertical or horizontal dimensions of extraction sockets nor induces more new bone formation.

CLINICAL RELEVANCE

This study helps dentists choose the appropriate material for ridge preservation.

Horizontal ridge augmentation in the maxillary aesthetic region using the autogenous circular cortical-lamina anchoring technique: A case series study

AIM

This case series aimed to evaluate the effectiveness of the autologous circular cortical lamina-anchoring (CCA) technique for horizontal bone augmentation in the maxillary aesthetic region.

MATERIALS AND METHODS

A total of 25 patients with 28 implants underwent horizontal bone augmentation using CCA followed by implant placement and crown delivery. The primary outcome measures were alveolar ridge width (ARW) and buccal bone thickness (BBT), whereas the secondary outcome measures included marginal bone loss (MBL), mid-facial mucosal margin loss (MML), clinical assessment of peri-implant and aesthetic parameters, patient-reported outcome measures (PROMs), and implant survival rates.

RESULTS

All 25 patients with 28 implants completed the treatment, no dropouts occurred. After CCA, the mean ARW at 1, 2, and 4 mm below the alveolar crest significantly increased from 2.38 ± 0.48, 2.85 ± 0.51, and 3.21 ± 0.53 mm to 6.80 ± 0.48, 6.99 ± 0.50, and 8.08 ± 0.52 mm, respectively. At the 3-year follow-up, the mean BBT0, BBT2, and BBT4 slightly decreased from 2.51 ± 0.26, 2.63 ± 0.31, and 2.75 ± 0.29 mm to 2.43 ± 0.27, 2.51 ± 0.30, and 2.64 ± 0.28 mm, respectively. Although the overall MBL was <0.15 mm, the results were statistically significant. The mean MML at the 3-year follow-up was 0.02 mm. All implant sites showed acceptable peri-implant and aesthetic outcomes. Incisions healed without complications, and no significant differences in PROMs observed at any time point. The 3-year follow-up showed a 100% implant survival rate.

CONCLUSION

The autologous CCA technique is a useful method for increasing ARW and maintaining BBT in the maxillary aesthetic region.

A Comparison of Guided Bone Regeneration vs. the Shell Technique Using Xenogeneic Bone Blocks in Horizontal Bone Defects: A Randomized Clinical Trial

In cases of severe horizontal atrophy, implant placement requires bone reconstruction procedures. The aim of this randomized controlled trial is to compare the outcomes of bone augmentation with simultaneous implant placement using the shell technique to the outcomes of guided bone regeneration (GBR) in cases of severely horizontal bone atrophy. This study was designed as a monocentric, parallel-group, randomized controlled trial with a six-month follow-up. Among the primary outcomes of this study, peri-implant bone regeneration and peri-implant bone defect closure were selected. Forty-four patients were recruited and equally divided between two groups. In the GRB group, a horizontal regeneration of 2.31 ± 0.23 mm was observed opposed to a horizontal regeneration of 2.36 ± 0.17 mm in the shell group (p = 0.87). A volumetric increase was observed in both groups, with an increase of 0.30 ± 0.12 cm3 in the GBR group and an increase of 0.39 ± 0.09 cm3 in the shell group, highlighting a significant difference between the two groups (p = 0.02). In conclusion, bone augmentation with simultaneous implant placement using the shell technique or guided bone regeneration in horizontal bone atrophy are both predictable therapeutic options.

Guided bone regeneration for peri-implant augmentation: A retrospective study comparing two surgical techniques with a mean follow-up of 26 months

OBJECTIVES

To introduce a modified guided bone regeneration (GBR) technique using intact periosteum and deproteinized bovine bone mineral (DBBM) for peri-implant augmentation and compare the clinical outcomes with those of conventional GBR.

MATERIALS AND METHODS

Patients who received peri-implant augmentation in posterior sites between 2015 and 2021 were reviewed in this study. Group A was treated with a modified GBR technique, and Group B was treated with conventional GBR. For group comparison, propensity score matching was performed with a sensitivity analysis. The implant survival rate, dimensional changes in hard tissue, marginal bone loss (MBL), and peri-implant parameters were evaluated.

RESULTS

In total, 114 implants from 98 patients were included. The implant survival rates were 95.74% in Group A and 95.00% in Group B during the follow-up period. At 6 months, the median horizontal thickness was recorded at 0.87 mm (IQ1-IQ3 = 0.00-1.75 mm) in Group A, exhibiting a relatively lower value compared to the corresponding measurement of 0.98 mm (IQ1-IQ3 = 0.00-1.89 mm) in Group B (p = .937). Vertical height displayed no statistically significant intergroup difference between the two groups (p = .758). The mean follow-up period was 25.83 ± 12.93 months after loading in Group A and 27.47 ± 21.29 months in Group B (p = .761). MBL and peri-implant parameters were comparable between the two groups.

CONCLUSIONS

Within the limitations of this study, the modified GBR technique using intact periosteum and DBBM grafting might be a viable alternative to correct bone defects around implants in molar and premolar sites.

Regeneration of alveolar bone defects in the experimental pig model: A systematic review and meta-analysis

OBJECTIVE

Pigs are emerging as a preferred experimental in vivo model for bone regeneration. The study objective was to answer the focused PEO question: in the pig model (P), what is the capacity of experimental alveolar bone defects (E) for spontaneous regeneration in terms of new bone formation (O)?

METHODS

Following PRISMA guidelines, electronic databases were searched for studies reporting experimental bone defects or extraction socket healing in the maxillae or mandibles of pigs. The main inclusion criteria were the presence of a control group of untreated defects/sockets and the assessment of regeneration via 3D tomography [radiographic defect fill (RDF)] or 2D histomorphometry [new bone formation (NBF)]. Random effects meta-analyses were performed for the outcomes RDF and NBF.

RESULTS

Overall, 45 studies were included reporting on alveolar bone defects or extraction sockets, most frequently in the mandibles of minipigs. Based on morphology, defects were broadly classified as 'box-defects' (BD) or 'cylinder-defects' (CD) with a wide range of healing times (10 days to 52 weeks). Meta-analyses revealed pooled estimates (with 95% confidence intervals) of 50% RDF (36.87%-63.15%) and 43.74% NBF (30.47%-57%) in BD, and 44% RDF (16.48%-71.61%) and 39.67% NBF (31.53%-47.81%) in CD, which were similar to estimates of socket-healing [48.74% RDF (40.35%-57.13%) and 38.73% NBF (28.57%-48.89%)]. Heterogeneity in the meta-analysis was high (I2 > 90%).

CONCLUSION

A substantial body of literature revealed a high capacity for spontaneous regeneration in experimental alveolar bone defects of (mini)pigs, which should be considered in future studies of bone regeneration in this animal model.

Macrophages in guided bone regeneration: potential roles and future directions

Guided bone regeneration (GBR) is one of the most widely used and thoroughly documented alveolar bone augmentation surgeries. However, implanting GBR membranes inevitably triggers an immune response, which can lead to inflammation and failure of bone augmentation. It has been shown that GBR membranes may significantly improve in vivo outcomes as potent immunomodulators, rather than solely serving as traditional barriers. Macrophages play crucial roles in immune responses and participate in the entire process of bone injury repair. The significant diversity and high plasticity of macrophages complicate our understanding of the immunomodulatory mechanisms underlying GBR. This review provides a comprehensive summary of recent findings on the potential role of macrophages in GBR for bone defects in situ. Specifically, macrophages can promote osteogenesis or fibrous tissue formation in bone defects and degradation or fibrous encapsulation of membranes. Moreover, GBR membranes can influence the recruitment and polarization of macrophages. Therefore, immunomodulating GBR membranes are primarily developed by improving macrophage recruitment and aggregation as well as regulating macrophage polarization. However, certain challenges remain to be addressed in the future. For example, developing more rational and sophisticated sequential delivery systems for macrophage activation reagents; addressing the interference of bone graft materials and dental implants; and understanding the correlations among membrane degradation, macrophage responses, and bone regeneration.

Platelet-rich fibrin as an autologous biomaterial for bone regeneration: mechanisms, applications, optimization

Platelet-rich fibrin, a classical autologous-derived bioactive material, consists of a fibrin scaffold and its internal loading of growth factors, platelets, and leukocytes, with the gradual degradation of the fibrin scaffold and the slow release of physiological doses of growth factors. PRF promotes vascular regeneration, promotes the proliferation and migration of osteoblast-related cells such as mesenchymal cells, osteoblasts, and osteoclasts while having certain immunomodulatory and anti-bacterial effects. PRF has excellent osteogenic potential and has been widely used in the field of bone tissue engineering and dentistry. However, there are still some limitations of PRF, and the improvement of its biological properties is one of the most important issues to be solved. Therefore, it is often combined with bone tissue engineering scaffolds to enhance its mechanical properties and delay its degradation. In this paper, we present a systematic review of the development of platelet-rich derivatives, the structure and biological properties of PRF, osteogenic mechanisms, applications, and optimization to broaden their clinical applications and provide guidance for their clinical translation.

Application of sticky bone combined with concentrated growth factor (CGF) for horizontal alveolar ridge augmentation of anterior teeth: a randomized controlled clinical study

OBJECTIVE

This study was designed to estimate the effect of sticky bone combined with concentrated growth factor (CGF) on anterior alveolar horizontal augmentation during implantation.

METHODS

Twenty-eight patients were randomly assigned to either the test group (Group 1, n = 14) or the control group (Group 2, n = 14). Patients in Group 1 and Group 2 underwent GBR using sticky bone combined with CGF and bone powders mixed with saline, respectively. On postoperative Day 7, the patients completed the visual analogue scale (VAS). Three-dimensional models of maxillary alveolar bone were reconstructed from CBCT data at different periods, and the bone volume conversion rate was calculated with the assistance of a measurement marker guide. Labial bone thickness before and after trauma closure and bone density at six months postoperatively were also measured.

RESULTS

The mean bone volume conversion rate for Group 1 (72.09 ± 12.18%) was greater than that for Group 2 (57.47 ± 9.62%, P = 0.002). The VAS score was lower for Group 1 than for Group 2 (P = 0.032). At six months postoperatively, greater bone density was found in patients in Group 1 than in those in Group 2, although the difference was not statistically significant (P > 0.05). The change in the thickness of the labial bone graft material in Group 1 was smaller than that in Group 2 (P = 0.025).

CONCLUSION

Sticky bone combined with CGF was able to achieve better bone augmentation than conventional GBR. With excellent mechanical properties and the capacity to release growth factors, sticky bone is an ideal material for bone grafting.

TRIAL REGISTRATION

The study was registered at the Chinese Clinical Trial Registry on 10/04/2022 (Identification number: ChiCTR2200058500).

Horizontal GBR with anorganic equine bone combined with a customized titanium mesh

This case report describes the fixed rehabilitation of the lower left arch in a patient following an horizontal GBR procedure by means of a customized titanium mesh and a new slow resorption bone substitute of equine origin.

Sinus floor augmentation using mineralized freeze-dried bone allograft combined with recombinant human bone morphogenetic protein-2 (rhBMP-2): A long-term retrospective study

Background/purpose

The combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) with a carrier material has not been extensively studied. This study aimed to evaluate the clinical, radiological, and histomorphometric outcomes of sinus floor augmentation using a 3:7 mixture of cancellous and cortical freeze-dried bone allografts (mixed AG) combined with rhBMP-2.

Materials and methods

Mixed AG was used for sinus floor augmentation in a total of 21 patients with a residual alveolar bone height <5 mm. Among the total 47 sites, augmentation with and without rhBMP-2 was performed in 26 and 21 sites, respectively. Radiographic parameters were assessed using cone-beam computed tomography. After a six-month healing period, core biopsies were harvested for histomorphometric analysis.

Results

The bone gain after healing was 13.36 ± 3.9 mm and 12.07 ± 3.8 mm in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively. The survival rate of implants in both groups was 100% during the follow-up period. The proportion of newly formed bone was 24.6 ± 10.2% and 39.7 ± 18.3% in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively (P < 0.05). Moreover, the percentage of residual graft material was 21.0 ± 12.2% and 9.6 ± 10.0% in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively (P < 0.05).

Conclusion

Mixed AG combined with rhBMP-2 could be a suitable material for sinus floor augmentation. This combination may reduce the treatment time and improve the predictability of implant placement.

Modulation of gene expression and bone formation by expanded and dense polytetrafluoroethylene membranes during guided bone regeneration: An experimental study

BACKGROUND

Nonresorbable membranes promote bone formation during guided bone regeneration (GBR), yet the relationships between membrane properties and molecular changes in the surrounding tissue are largely unknown.

AIM

To compare the molecular events in the overlying soft tissue, the membrane, and the underlying bone defect during GBR using dual-layered expanded membranes versus dense polytetrafluoroethylene (PTFE) membranes.

MATERIALS AND METHODS

Rat femur defects were treated with either dense PTFE (d-PTFE) or dual-layered expanded PTFE (dual e-PTFE) or left untreated as a sham. Samples were collected after 6 and 28 days for gene expression, histology, and histomorphometry analyses.

RESULTS

The two membranes promoted the overall bone formation compared to sham. Defects treated with dual e-PTFE exhibited a significantly higher proportion of new bone in the top central region after 28 days. Compared to that in the sham, the soft tissue in the dual e-PTFE group showed 2-fold higher expression of genes related to regeneration (FGF-2 and FOXO1) and vascularization (VEGF). Furthermore, compared to cells in the d-PTFE group, cells in the dual e-PTFE showed 2.5-fold higher expression of genes related to osteogenic differentiation (BMP-2), regeneration (FGF-2 and COL1A1), and vascularization (VEGF), in parallel with lower expression of proinflammatory cytokines (IL-6 and TNF-α). Multiple correlations were found between the molecular activities in membrane-adherent cells and those in the soft tissue.

CONCLUSION

Selective surface modification of the two sides of the e-PTFE membrane constitutes a novel means of modulating the tissue response and promoting bone regeneration.

Deep learning for the identification of ridge deficiency around dental implants

OBJECTIVES

This study aimed to use a deep learning (DL) approach for the automatic identification of the ridge deficiency around dental implants based on an image slice from cone-beam computerized tomography (CBCT).

MATERIALS AND METHODS

Single slices crossing the central long-axis of 630 mandibular and 845 maxillary virtually placed implants (4-5 mm diameter, 10 mm length) in 412 patients were used. The ridges were classified based on the intraoral bone-implant support and sinus floor location. The slices were either preprocessed by alveolar ridge homogenizing prior to DL (preprocessed) or left unpreprocessed. A convolutional neural network with ResNet-50 architecture was employed for DL.

RESULTS

The model achieved an accuracy of >98.5% on the unpreprocessed image slices and was found to be superior to the accuracy observed on the preprocessed slices. On the mandible, model accuracy was 98.91 ± 1.45%, and F1 score, a measure of a model's accuracy in binary classification tasks, was lowest (97.30%) on the ridge with a combined horizontal-vertical defect. On the maxilla, model accuracy was 98.82 ± 1.11%, and the ridge presenting an implant collar-sinus floor distance of 5-10 mm with a dehiscence defect had the lowest F1 score (95.86%). To achieve >90% model accuracy, ≥441 mandibular slices or ≥592 maxillary slices were required.

CONCLUSIONS

The ridge deficiency around dental implants can be identified using DL from CBCT image slices without the need for preprocessed homogenization. The model will be further strengthened by implementing more clinical expertise in dental implant treatment planning and incorporating multiple slices to classify 3-dimensional implant-ridge relationships.

Ridge preservation using a self-retaining block type bone substitute for extraction sockets with buccal dehiscence defects - A preclinical study

OBJECTIVE

To evaluate the effect of a self-retaining block-type bone substitute (srBB) on the dimensional stability of the horizontal ridge width at the coronal level in a buccal dehiscence model.

MATERIALS AND METHODS

Four box-shaped bone defects with a buccal dehiscence were surgically prepared in the partially edentulous mandible (n = 6). Experimental biomaterials were randomly assigned to each site: (1) Control group: no treatment, (2) particle-type bone substitute (PBS) group, (3) collagenated soft block bone substitute (csBB) group, and (4) self-retaining synthetic block bone (srBB) group. In all grafted groups, a collagen membrane covered the biomaterials. At 16 weeks, clinical, histological, and radiographic analyses were performed.

RESULTS

Three of the six blocks in the srBB group became exposed and fell out during the first week after surgery. Therefore, the remaining three specimens were renamed RsrBB group. The RsrBB group showed an increase horizontal ridge compared to the pristine bone width at 2-4 mm below the CEJ, while the other groups showed resorption (augmented width at 2 mm below: 4.2, 42.4, 36.2, and 110.1% in the control, PBS, csBB, and RsrBB groups, respectively). The mineralized bone area was largest in the RsrBB group (4.74, 3.44, 5.67, and 7.77 mm2 in the control, PBS, csBB, and RsrBB groups, respectively.).

CONCLUSIONS

The srBB group demonstrated the highest volume stability at the coronal level. These findings would potentially suggest that self-retaining block bone substitute might be a good candidate for alveolar ridge preservation.

Is transmucosal healing of an implant as effective as submerged healing when simultaneous guided bone regeneration is performed? A preclinical study

AIM

To investigate whether transmucosal healing is as effective as submerged healing in terms of buccal bone regeneration when guided bone regeneration (GBR) is performed simultaneously with implant placement.

MATERIALS AND METHODS

In six dogs, buccal dehiscence defects were created in the edentulous mandibular ridge, sized 5 × 5 × 3 mm (length × height × depth). In each defect, a bone-level implant was placed, and four experimental groups were randomly assigned as follows: (i) transmucosal healing with GBR (T-GBR), (ii) transmucosal healing without GBR (T-control), (iii) submerged healing with GBR (S-GBR) and (iv) submerged healing without GBR (S-control). Data analyses were based on histological slides 5 months after implant placement.

RESULTS

The T-GBR group showed significant differences compared to the control groups regarding defect height resolution, buccal bone thickness and mineralized tissue area (p < .05), but showed no significant differences when compared with the S-GBR group (p > .05).

CONCLUSIONS

The mode of healing (transmucosal vs. submerged) does not influence bone regeneration at implant sites. The clinician may therefore choose the approach based on further clinical and patient-specific parameters.