Peri‐implant defect grafting with autogenous bone or bone graft material in immediate implant placement in molar extraction sites—1‐ to 3‐year results of a prospective randomized study

Immediately placed implants using simvastatin and autogenous tooth graft combination in periodontally compromised sites: a randomized controlled clinical trial

OBJECTIVES

The present study aimed to assess clinically and radiographically the usage of autogenous tooth bone graft (ATBG) combined with and without Simvastatin (SMV) around immediately placed dental implants in periodontally compromised sites.

METHODS

Thirty-nine patients required a single extraction of periodontally compromised tooth were divided into three groups (13 patients each). Group I received immediate implant placement (IIP) without grafting. Group II received IIP with ATBG filling the gap around IIP. Group III received SMV gel mixed with ATBG around IIP. Radiographic changes were reported at the baseline, 6-, and 12-months post-surgery.

RESULTS

All implants achieved the success criteria with no complications. At 6- and 12-months post-surgery, group III showed a statistically lower mean ridge width loss compared to Group I and Group II (P < .001). Group II revealed less reduction in the mean alveolar ridge width compared to group I (P < .001). Group III showed a statistically significantly less MBL loss than group I and group II (P < .001). All groups showed a statistically significant increase in BD gain compared to baseline (P < .001). Group III showed statistically significant high BD compared to group II (P < .001). Group II showed statistically significantly higher mean BD gain than that of group I (P < .001).

CONCLUSION

SMV combined with ATBG boosts the hard tissue parameters around dental implants over ATBG alone. Clinical trial registration was on August 1, 2021 (NCT04992416).

CLINICAL RELEVANCE

ATBG with SMV in periodontally compromised sites could improve implant osseointegration and promote favorable changes in peri-implant tissues.

The Use of Tissue Grafts Associated with Immediate Implant Placement to Achieve Better Peri-Implant Stability and Efficacy: A Systematic Review and Meta-Analysis

Background: The goal of this systematic study and meta-analysis was to evaluate the efficacy of hard and/or soft tissue grafts associated with type-1 implants on healing and treatment outcomes. The primary outcomes studied were implant survival rate, pocket depth, marginal peri-implant recession, bone loss, bone thickness (volumetric change), interproximal bone level, mesial and distal papilla migration, and radiographic evaluation; and the secondary parameters were Pink Esthetic Score (PES), vertical distance from implant shoulder and bone, Visual Analogue Score (VAS), Implant Stability Quotient (ISQ), and biological complications (fistulas, pain, mucositis, and peri-implantitis). Methods: The PICO strategy was used to formulate the hypothesis under study: "For patients who underwent extraction and immediate implant placement, what is the efficacy of using any type of graft (bone or soft tissue) compared to non-grafting regarding the peri-implant parameters?" The electronic search process was performed on the MedLine/PubMed and Cochrane databases. It included randomized controlled trials (RCTs) from the last 11 years (from 2012 to November 2023), which were identified and analyzed. Results: Nine RCTs (κ = 0.98) were selected (403 patients and 425 implants); they were divided into three groups: bone graft (75 patients and 75 implants inserted), bone graft and membrane (213 patients and 235 implants inserted), and without bone graft (115 patients and 115 implants inserted). Three studies calculated the mid-facial mucosa level and two reported better results when a connective tissue graft was combined with the xenograft, whereas another study found better results in the combination of a dual-zone technique with a xenograft. Three studies evaluated the total Pink Esthetic Score (PES) at 12 months, where the authors found no significant difference in using a xenogeneic graft with or without a membrane. In the same period, the facial bone thickness was assessed in two articles; the authors reported better results in graft-treated and flapless groups. The risk-of-bias assessment found four studies with low risk, four with moderate risk, and one with a high risk of bias. The meta-analysis showed a medium level of heterogeneity for the mid-facial mucosa level analysis (I2 = 46%) and an overall effect size of 0.79 (95% CI [0.18; 1.40]), a statistically significant results (p = 0.01), with a tendency to favor the experimental group. Also, there was a medium level of heterogeneity among studies regarding total PES (I2 = 45%), with no significant differences between studies (p = 0.91). Homogeneous results (I2 = 0%) were found among studies analyzing facial bone thickness, favoring the experimental group; the forest plot showed an effect of 0.37 (95% CI [0.25; 0.50]), which was statistically significant (p < 0.00001) for this parameter. Conclusions: Then, it was possible to conclude that using bone and soft tissue grafting techniques associated with immediate implant placement (IIP), even though they are not fundamental, was a valuable resource to prevent significant tissue reduction, reaching greater bone stability and higher levels in the Pink Esthetic Score (PES) and Visual Analogue Score (VAS).

Osseointegration Potential Assessment of Bone Graft Materials Loaded with Mesenchymal Stem Cells in Peri-Implant Bone Defects

Many studies have been exploring the use of bone graft materials (BGMs) and mesenchymal stem cells in bone defect reconstruction. However, the regeneration potential of Algipore (highly purified hydroxyapatite) and Biphasic (hydroxyapatite/beta-tricalcium phosphate) BGMs combined with bone marrow-derived mesenchymal stem cells (BMSCs) remains unclear. Therefore, we evaluated their osseointegration capacities in reconstructing peri-implant bone defects. The cellular characteristics of BMSCs and the material properties of Algipore and Biphasic were assessed in vitro. Four experimental groups-Algipore, Biphasic, Algipore+BMSCs, and Biphasic+BMSCs-were designed in a rabbit tibia peri-implant defect model. Implant stability parameters were measured. After 4 and 8 weeks of healing, all samples were evaluated using micro-CT, histological, and histomorphometric analysis. In the energy-dispersive X-ray spectroscopy experiment, the Ca/P ratio was higher for Algipore (1.67) than for Biphasic (1.44). The ISQ values continuously increased, and the PTV values gradually decreased for all groups during the healing period. Both Algipore and Biphasic BGM promoted new bone regeneration. Higher implant stability and bone volume density were observed when Algipore and Biphasic BGMs were combined with BMSCs. Biphasic BGM exhibited a faster degradation rate than Algipore BGM. Notably, after eight weeks of healing, Algipore with BSMCs showed more bone-implant contact than Biphasic alone (p < 0.05). Both Algipore and Biphasic are efficient in reconstructing peri-implant bone defects. In addition, Algipore BGM incorporation with BSMCs displayed the best performance in enhancing implant stability and osseointegration potential.

Tissue-engineered bone construct promotes early osseointegration of implants with low primary stability in oversized osteotomy

OBJECTIVES

To evaluate the histological parameters and bone mechanical properties around implants with low primary stability (PS) in grafted bone substitutes within an oversized osteotomy.

MATERIALS AND METHODS

An oversized osteotomy penetrating the double cortical bone layers was made on both femora of 24 New Zealand white rabbits. Bilaterally in the femur of all animals, 48 implants were installed, subdivided into four groups, corresponding to four prepared tissue-engineering bone complexes (TEBCs), which were placed between the implant surface and native bone wall: A: tricalcium phosphate β (TCP-β); B: autologous adipose derived-stem cells with TCP-β (ASCs/TCP-β); C: ASCs transfected with the enhanced-GFP gene with TCP-β (EGFP-ASCs/TCP-β); D: ASCs transfected with the BMP-2 gene with TCP-β (BMP2-ASCs/TCP-β). Trichrome fluorescent labeling was conducted. Animals were sacrificed after eight weeks. The trichromatic fluorescent labeling (%TFL), area of new bone (%NB), residual material (%RM), bone-implant contact (%BIC), and the removal torque force (RTF, N/cm) were assessed.

RESULTS

ASCs were successfully isolated from adipose tissue, and the primary ASCs were induced into osteogenic, chondrogenic, and adipogenic differentiation. The BMP-2 overexpression of ASCs sustained for ten days and greatly enhanced the expression of osteopontin (OPN). At eight weeks post-implantation, increased %NB and RTF were found in all groups. The most significant value of %TFL, %BIC and lowest %RM was detected in group D.

CONCLUSION

The low PS implants osseointegrate with considerable new bone in grafted TEBCs within an oversized osteotomy. Applying BMP-2 overexpressing ASCs-based TEBC promoted earlier osseointegration and more solid bone mechanical properties on low PS implants. Bone graft offers a wedging effect for the implant with low PS at placement and promotes osteogenesis on their surface in the healing period.

Critical review on bone grafting during immediate implant placement

In the last 20 years, immediate implant placement has been proposed as a predictable protocol to replace failing teeth. The research conducted in preclinical and clinical studies have focused on soft and hard tissue changes following tooth extraction and immediate implant placement. Different approaches for hard and soft tissue grafting together with provisional restorations have been proposed to compensate tissue alterations. This review analyzed some relevant clinical and preclinical literature focusing on the impact of bone grafting procedures on immediate implant placement in terms of hard and soft tissue changes, aesthetic results, and patient-related outcomes.

Identification of key pathways in zirconia/dental pulp stem cell composite scaffold-mediated macrophage polarization through transcriptome sequencing

Seed cells and scaffold materials are essential components of tissue engineering. In this study, we investigated the key pathway of the zirconia/dental pulp stem cell composite scaffold in regulating macrophage polarization by transcriptome sequencing. We established N-rGO/ZrO2 composite scaffold and confirmed its structure using various analytical techniques, including SEM, TEM, FTIR, Raman spectra, XPS, and XRD. DPSCs were seeded onto N-rGO/ZrO2 composite scaffold material, and their proliferation, adhesion, and osteogenic differentiation were evaluated by CCK-8, immunofluorescence staining, ALP staining, and alizarin red staining. We then co-cultured DPSCs combined with N-rGO/ZrO2 as composite material with THP-1 cells in a transwell system to investigate the effect of the composite on macrophage polarization. The levels of pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes were assessed by RT-qPCR and western blot. Through bulk RNA sequencing, we detected the transcriptional characteristics of macrophages under the regulation of the composite materials, and identified the differential genes using the DEseq2 package. We also analyzed the cellular and molecular functions of differentially expressed genes (DEGs) in THP-1 cells with DPSCs combined with N-rGO/ZrO2 treatment using GO enrichment analysis and KEGG pathway enrichment analysis. Our results showed that N-rGO/ZrO2 composite scaffold promoted the proliferation, adhesion, and osteogenic differentiation of DPSCs. Moreover, N-rGO/ZrO2 composite scaffold combined with DPSCs regulated macrophage migration, polarization, and glycolysis. Mechanistically, the combination of N-rGO/ZrO2 composite materials and DPSCs regulated macrophage polarization by activating the TNF signaling pathway. This finding provides a new approach to the clinical preservation of maxillofacial bone defect repair.

Efficacy of bone-substitute materials use in immediate dental implant placement: A systematic review and meta-analysis

OBJECTIVE

To assess the efficacy of using a bone substitute material (BSM) in the fixture-socket gap in patients undergoing tooth extraction and immediate implant placement.

MATERIALS AND METHODS

MEDLINE, EMBASE, and CENTRAL databases were searched for randomized controlled trials (RCTs). RCTs were screened for eligibility, and data were extracted by two authors independently. Risk of bias (ROB) was assessed using Cochrane's ROB tool 2.0. Primary outcomes were implant failure, overall complications, and soft-tissue esthetics. Secondary outcomes were vertical buccal bone resorption, vertical interproximal bone resorption, horizontal buccal bone resorption, and mid-buccal mucosal recession. Meta-analysis was performed using random-effects model with generic inverse variance weighing. GRADE was used to grade the certainty of the evidence.

RESULTS

After screening 19 544 potentially eligible references, 20 RCTs were included in this review, with a total of 848 patients (916 sites). Most included RCTs were deemed of some concerns (53%) or at low (38%) risk of bias, except for overall complications (high ROB). Implant failure did not differ significantly RR = 0.92 (confidence intervals [CI] 0.34 to 2.46) between using a BSM compared with not using a BSM (NoBSM). BSM use resulted in less horizontal buccal bone resorption (MD = -0.52 mm [95% CI -0.74 to -0.30]), a higher esthetic score (MD = 1.49 [95% CI 0.46 to 2.53]), but also more complications (RR = 3.50 [95% CI 1.11 to 11.1] compared with NoBSM. Too few trials compared types of BSMs against each other to allow for pooled analyses. The certainty of the evidence was considered moderate for all outcomes except implant failure (low), overall complications (very low), and vertical interproximal bone resorption (very low).

CONCLUSION

BSM use during immediate implant placement reduces horizontal buccal bone resorption and improves the periimplant soft-tissue esthetics. Although BSM use increases the risk of predominantly minor complications.

Immediate implant placement in fresh extraction sockets

Immediate implant placement (IIP) in fresh extraction sockets exhibits similar survival and success rates to delayed implant placement in healed sockets. Several advantages of IIP involve shortened total treatment time, reduction of the number of invasive surgeries, and subsequent reduction of patient discomfort due to lack of additional surgeries. The major shortcomings in IIP, however, include the inability to obtain early bony support, presence of a gap between the extraction socket and fixture, and the inability to cover the fixture with soft tissue, leading to increased risk of infection and implant loss. When IIP is performed, atraumatic or minimally traumatic extractions, conservation of the septal bone in molars, minimal flap elevation or flapless surgery, bone grafting the gap between the fixture and the extraction socket, and coverage with soft tissue or a membrane must be considered.

Bone Regeneration Assessment of Polycaprolactone Membrane on Critical-Size Defects in Rat Calvaria

Biomaterials for use in guided bone regeneration (GBR) are constantly being investigated and developed to improve clinical outcomes. The present study aimed to comparatively evaluate the biological performance of different membranes during the bone healing process of 8 mm critical defects in rat calvaria in order to assess their influence on the quality of the newly formed bone. Seventy-two adult male rats were divided into three experimental groups (n = 24) based on the membranes used: the CG—membrane-free control group (only blood clot, negative control), BG—porcine collagen membrane group (Bio-Guide^®, positive control), and the PCL—polycaprolactone (enriched with 5% hydroxyapatite) membrane group (experimental group). Histological and histometric analyses were performed at 7, 15, 30, and 60 days postoperatively. The quantitative data were analyzed by two-way ANOVA and Tukey’s test (p < 0.05). At 7 and 15 days, the inflammatory responses in the BG and PCL groups were significantly different (p < 0.05). The PCL group, at 15 days, showed a large area of newly formed bone. At 30 and 60 days postoperatively, the PCL and BG groups exhibited similar bone healing, including some specimens showing complete closure of the critical defect (p = 0.799). Thus, the PCL membrane was biocompatible, and has the potential to help with GBR procedures.