Influence of the use of autogenous bone particles to close the access window after maxillary sinus floor augmentation: an experimental study in rabbits

Influence of the use of autogenous bone particles to close the access window after maxillary sinus floor augmentation: a micro-computed tomography and positron emission tomography study in rabbits

AIM

The purpose of this study was to evaluate using microCT and positron emission tomography (PET) analysis, the influence on bone healing of the placement of particulate autogenous bone in the antrostomy, and in the subjacent region after maxillary sinus elevation with xenograft.

MATERIAL AND METHODS

The sinus mucosa was elevated in sixteen male New Zealand rabbits and they were both grafted with a collagenated cortico-cancellous porcine bone. The antrostomy and the near subjacent region were filled with either the same xenograft (control site) or with particulate autogenous bone (test site) harvested from the tibia. The antrostomies were covered with collagen membranes. MicroCT (measured in Hounsfield Units) and microPET (kBq/cm3) using sodium fluoride infiltration (18F-NaF) were performed at the time of euthanasia that was performed after 1 and 8 weeks of healing, using 8 animals in each group. The Wilcoxon test was used for analysis.

RESULTS

At the microCT analysis, after 1 and 8 weeks of healing, no statistically significant differences were found between groups. Bone increased and xenograft decreased significantly between the two periods of healing. At the microPET analysis, the percentage of bone increased significantly over time in both test and control groups and no significant differences were found between groups.

CONCLUSION

The placement of autogenous bone in the antrostomy and the subjacent region after maxillary sinus elevation did not enhance bone formation compared with sites where only xenograft was used. Both microCT and microPET showed increase bone formation over time.

A Narrative Review on the Effectiveness of Bone Regeneration Procedures with OsteoBiol® Collagenated Porcine Grafts: The Translational Research Experience over 20 Years

Over the years, several bone regeneration procedures have been proposed using natural (autografts, allografts, and xenografts) and synthetic (i.e., metals, ceramics, and polymers) bone grafts. In particular, numerous in vitro and human and animal in vivo studies have been focused on the discovery of innovative and suitable biomaterials for oral and maxillofacial applications in the treatment of severely atrophied jaws. On this basis, the main objective of the present narrative review was to investigate the efficacy of innovative collagenated porcine bone grafts (OsteoBiol^®, Tecnoss^®, Giaveno, Italy), designed to be as similar as possible to the autologous bone, in several bone regeneration procedures. The scientific publications were screened by means of electronic databases, such as PubMed, Scopus, and Embase, finally selecting only papers that dealt with bone substitutes and scaffolds for bone and soft tissue regeneration. A total of 201 papers have been detected, including in vitro, in vivo, and clinical studies. The effectiveness of over 20 years of translational research demonstrated that these specific porcine bone substitutes are safe and able to improve the biological response and the predictability of the regenerative protocols for the treatment of alveolar and maxillofacial defects.

Radiographic and Histomorphologic Evaluation of the Maxillary Bone after Crestal Mini Sinus Lift Using Absorbable Collagen—Retrospective Evaluation

Background: After tooth extraction, the alveolar bone loses volume in height and width over time, meaning that reconstructive procedures may be necessary to perform implant placement. In the maxilla, to increase the bone volume, a mini-invasive surgery, such as a sinus lift using the crestal approach, could be performed. Methods: A crestal approach was used in this study to perform the sinus lift, fracturing the bone and inserting collagen (Condress^®). The single dental implant was placed in the healed bone after six months. Results: The newly formed bone was histologically analyzed after healing. Histomorphological analyses confirmed the quality of the new bone formation even without graft biomaterials. This is probably due to the enlargement of the space, meaning more vascularization and stabilization of the coagulum. Conclusion: Using just collagen could be sufficient to induce proper new bone formation in particular clinical situations, with a minimally invasive surgery to perform a sinus lift.

Maxillary Sinus Augmentation Using Ceramic Alloplastic Granules or Paste: An Experimental Study in Rabbits

BACKGROUND

Due to the lack of data comparing the biological behavior of two formulations, granules and paste, of alloplastic graft from microtomographic and histomorphometric points of view, the aim of the present experiment was to compare the histomorphometric and microtomographic healing of two formulations, i.e., granules (MR sites) or paste (MR-inject sites) of an alloplastic graft composed of a combination of beta-tricalcium phosphate and hydroxyapatite used for maxillary sinus lifting.

METHODS

A sinus lifting procedure was carried out bilaterally in 20 rabbits, and the elevated space was filled with either paste or granules of an alloplastic material. A collagen membrane was placed on the antrostomy and the animals were euthanized after 2 or 10 weeks, 10 animals each group. Microtomographic and histological analyses were performed.

RESULTS

Higher proportions of new bone formation were found at the MR, compared to the MR-inject sites both after 2 weeks (2.65 ± 2.89% vs. 0.08 ± 0.12%; p < 0.01) and 10 weeks of healing (34.20 ± 13.86 vs. 23.28 ± 10.35%; p = 0.022).

CONCLUSIONS

It was concluded that new bone formation was faster in the MR sites, compared to the MR-inject. However, a longer time of healing should be allowed to make final conclusions about the efficiency in bone formation of the paste formulation of the biomaterial used in the present study.

New bone ingrowth into β-TCP/HA graft activated with argon plasma: a histomorphometric study on sinus lifting in rabbits

BACKGROUND

In a previous experimental study, new bone was found growing within granules of HA/β-TCP. In vitro and experimental studies have shown increased protein adsorption and cell adhesion graft material bioactivated with Argon plasma. The aims of the present experiment were to study new bone ingrowth into β-TCP/HA granules used as filler material for sinus lifting and the influence on the healing of the bioactivation of the graft with argon plasma.

METHODS

Sinus lifting was carried out in 20 rabbits using 60% HA and 40% β-TCP as filler material either bio-activated with argon plasma (plasma group) or left untreated (control group). The antrostomies were closed with collagen membranes. Biopsies representing the healing after 2 and 10 weeks were collected, and ground sections were prepared for histomorphometric analyses. Various regions of the elevated space were analyzed both around (outer bone; OB) and inside (interpenetrating bone network, IBN) the graft particles.

RESULTS

After 2 weeks of healing, 8.2% and 9.3% (n = 10; p = 0.635) of total new bone (OB + IBN) was found in the plasma and control groups, respectively. Small fractions of IBN were found, spreading from the periphery inward of the graft particles. After 10 weeks of healing, the total new bone was 34.0% in the plasma and 31.3% in Control groups (n = 9; p = 0.594). The respective fractions of IBN were 18.0% and 16.0%. New bone was penetrating from the peripheral regions inside the remnants of graft particles, where it was forming a network of bridges in continuity to the remnants of biomaterial through its porosities. The biomaterial decreased in proportion between 2 and 10 weeks from 52.1 to 28.3% in the plasma group, and from 52.5% to 31.9% in the control group.

CONCLUSION

The bio-activation with argon plasma on a synthetic graft composed of 60% HA and 40% β-TCP used as filler material for sinus lifting showed a tendency to improve bone formation; however, the difference with the control group was neither statistically significant nor clinically relevant.