Histomorphometric evaluation, SEM, and synchrotron analysis of the biological response of biodegradable and ceramic hydroxyapatite-based grafts: from the synthesis to the bed application

Evaluation of low-crystallinity apatite as a novel synthetic bone graft material: In vivo and in vitro analysis

OBJECTIVES

To overcome the shortcomings of sintered bone graft materials, low-crystallinity apatite (LCA) was developed using a non-heated approach to enhance resorption and integration during bone regeneration. This study aimed to evaluate the efficacy of LCA as a synthetic bone graft material for bone reconstruction.

METHODS

LCA was compared to three conventional synthetic bone graft materials: biphasic calcium phosphate (BCP) 37, BCP 64, and octacalcium phosphate (OCP). Crystalline structure and surface morphology were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). In vivo testing was conducted using a rabbit calvarial augmentation model, in which the grafts were placed into standardized defects. Bone formation and graft resorption were analyzed using micro-computed tomography (micro-CT) and histomorphometric analyses at three and six weeks post-implantation.

RESULTS

LCA exhibited structural similarities to the allograft material and enhanced surface properties. Micro-CT and histomorphometric evaluations at three and six weeks post-implantation demonstrated higher rates of bone formation and substantial volumetric changes with LCA, indicating efficient graft resorption and bone regeneration.

CONCLUSIONS

LCA exhibited superior integration, osteoconductivity, and biodegradability compared to other synthetic grafts, suggesting the potential for improved clinical outcomes with its use. Although the efficacy of LCA has been validated, further studies in diverse biological environments are necessary to confirm its safety and effectiveness for broader clinical use.

CLINICAL SIGNIFICANCE

LCA, which mimics natural bone structure and has superior integration and osteoconductivity, has the potential for clinical applications requiring rapid and effective bone healing.

Effects of Preparation Technique on Periosteal Microcirculation After Autologous Bone Augmentation in an Animal Model

This controlled in vivo experimental study examines the impact of 2 periosteum preparation techniques on microcirculation during bone augmentation with isogenic bone grafts in rats. Twenty female Lewis rats were divided into 2 groups (n = 10 each). In one group, the periosteum was prepared with a conventional periosteal elevator; in the other, a piezoelectric device was used. After graft implantation at calvarial sites, intravital microscopy was performed postoperation (day 0) and on days 3, 8, and 28 immediately to assess microvascular parameters: functional capillary density, blood flow velocity, and vessel diameter. Statistical analysis was conducted using analysis of variance on ranks with P < .05. The piezoelectric device group showed higher mean values for functional capillary density, blood flow velocity, and vessel diameter than the conventional instrument group, though differences were not statistically significant. This study suggests that periosteum preparation with a piezoelectric device does not significantly differ from conventional methods regarding microcirculatory outcomes. Either method appears viable for preserving microcirculatory integrity during bone augmentation. Further research in larger models and clinical contexts is recommended to confirm these findings.

Systematic Review Regarding the Clinical Implications of Allograft and Alloplastic Bone Substituents Used for Periodontal Regenerative Therapy

Background/Objectives: Regenerative periodontal therapy is a treatment method that focuses on restoring the periodontium affected by chronic inflammatory disease or injury. It involves using different biomaterials and techniques to completely restore the periodontal structures. The main objective was to identify and critically evaluate relevant studies comparing the clinical efficacy of allograft and alloplastic materials in regenerative periodontal therapy. Methods: For evaluation, a systematic review based on PRISMA guidelines was conducted. Data were extracted using only specific types of study designs, which included randomized controlled trials, cohort studies, and case-control studies. Target patients with periodontal disease or periodontal lesions undergoing periodontal therapy using allograft or alloplastic materials were selected. Periodontal parameters such as clinical attachment level, probing pocket depth, radiographic bone fill, or patient-reported outcomes were analyzed. Results: The results showed that allograft and alloplastic materials offered reduced pocket depth, a gain in clinical attachment, and bone repairment. The variation observed indicated that allografts showed a slightly more significant clinical attachment gain and a superior bone fill than alloplastic ones, suggesting that allografts enhance osteogenesis and provide a greater capacity for repair in periodontal defects. Conclusions: The results of the present study suggest that allograft and alloplastic materials offered reduced pocket depth, a gain in clinical attachment, and bone repairment, with both methods having similar clinical efficacy.

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.

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).