Case Report: The effect of bone morphogenetic proteins (BMP) in comparison with a xenograft in the management of mandibular bone defects

Introduction

Bone defects in the jaw are a common problem faced by oral and maxillofacial surgeons, especially when dental implants are needed within the bone. This deficiency is due to several reasons, the most important of which are periodontal tissue diseases, cysts, and severe surgical trauma during extraction.¹

Several techniques have been described to compensate for and speed up the healing of defective bone for the purpose of placing dental implants or avoiding fracture or deformation of the bone.²

Xenografts, such as inorganic bovine bone grafts, have been widely used to achieve three-dimensional healing of the maxillary bone in the field of repair of defects and alveolar resorption in several studies.³

Many studies have examined the process of improving and accelerating bone healing by relying on many growth factors present in platelet-rich plasma, the most important of which are bone-forming proteins, in addition to the use of growth-directed membranes, which concluded that they can stimulate the mechanisms of chemotaxis, cell division, and cell differentiation, and the use of hemostatic sponges have been included in some studies as carriers of medicinal materials or a scaffold for osteoblasts.⁴

In a latest 2020 study, Vasyliev et al. investigated the effect of adding a low dose of 10 g/ml bone morphogenetic proteins to a Bio Oss^® inorganic bovine bone graft to stimulate bone formation in rabbits.⁵

To date, obtaining the best material for the restoration of defective bony cavities in the jaws, in the fastest and best way to stimulate bone formation, and with the least possible complications and costs, is one of the most significant concerns of oral and maxillofacial surgeons worldwide.

Esfahanizadeh et al. studied the efficacy of a Bio Oss^® bone graft on bone defects and concluded that this graft supported bone morphogenesis in defects made in rabbit tibias.⁶

Tavakoli et al. found that applying hemostatic sponges to alveolar bone sockets after extraction accelerates hemostasis, collagen, and connective tissue formation, and alleviates post-extraction complications.⁷

Sohn et al. applied gelatin sponge to nine patients with lateral window maxillary sinus lifts to support the lifted mucosa and found new bone formation six months after the operation.⁸

In their comparative study of artificial bone grafts and gelatin sponges, Singh et al. indicated that sponges are not as effective as grafts and cannot be used alone as an alternative to grafting in bone defects.⁹

Kim et al. applied gelatin sponges loaded with bone-forming proteins to a bony defect of the radius of a rabbit and confirmed the effectiveness of this participation in bone regeneration.¹⁰

As for Fiorellini et al., the application of a gelatin sponge impregnated with bone morphogenetic protein showed great efficacy in preserving alveolar bone after extraction.¹¹

This case report aims to compare the effectiveness of a gelatin sponge impregnated with bone-forming proteins with that of a Bio-Oss^® bone graft in healing and managing bone defects.

Case presentation

A 48-year-old Syrian woman who is currently unemployed

She does not suffer from any systemic or psychological diseases, and her father suffered a myocardial infarction, she suffered from gum disease and lack of oral care, which led to the loss of most of her teeth

She had two cysts in the mandibular bone (Figure 1), and clinical examination showed pain and swelling in the jaw on both sides under the roots of the deviated teeth (Figure 1).

Figure 1. Clinical photos for the case.

Diagnostic radiographic examination revealed two root cysts on both sides of the lower jaw (Figure 2).

Figure 2. Diagnostic panoramic and cone-beam computed tomography (CBCT) radiography.

Surgery was performed by extracting the roots of the remaining teeth and scraping the root cysts by using a bone shovel. Then, a gelatin sponge from ORCA^® Foam, Item No: 7156411 impregnated with bone-forming protein rh-bmp2 was placed within the left bone defect, and a BioOss bovine graft was placed within the right bone defect (Figure 3).

Figure 3. Clinical photos of the surgical operation.

A radiographic image was taken immediately after the surgery (Figure 4).

Figure 4. Radiographic image after surgery.

Then, radiological evaluation of the patient was conducted using cone-beam computed tomography (CBCT) images during the following observation periods (1, 3, and 6 months) as shown in, Figures 5, 6, 7.

Figure 5. Radiographic image after 1 month of the surgery.

Figure 6. Radiographic image after 3 months of the surgery.

Figure 7. Radiographic image after 6 months of the surgery.

For comparison between the results of the two subjects, the following radiological criteria were used:

The results are shown in Table 1.

After 6 months, a bone tissue biopsy was performed from the grafting area with a trephine bur of 2 mm in diameter and 5 mm in length. The cells were examined under a SKU: MI-4100LST microscope at 100× magnification (Figure 8).

Figure 8. Microscopic images of histological biopsies after 6 months.

The following criteria were adopted to compare the effects of the two materials on the bone healing of defects:

The results are shown in Table 2.

Discussion

The aim of this case report was to compare the effect of the bone morphogenic protein rh-BMP carried on the gelatin sponge with the effect of foreign bone graft BioOss in healing and accelerating bony defects in the mandible, and to determine the ability of these proteins to compete with the BioOss bone graft, which has already proven its effectiveness in many previous studies.

The patient had two root cysts under the premolars, on the right and left sides of the lower jaw. After scraping the two cysts, a gelatin sponge impregnated with the bone morphogenic protein rh-BMP (10 g/ml) was placed within the left bony defect. A BioOss bone graft was placed in the right cavity. Healing was evaluated radiologically and histologically. The results were similar with a slight advantage in the healing of the defect, by the BioOss bone graft.

The radiological density of the new bone tissue formed within the bone defects was measured after (1, 3, and 6 months by measuring the Hounsfield units on digital radiographs after they were inserted into the computer program Digora for Windows 2.7.

The results of this study showed that the density after one month, three months and six months in the BMP2 group did not differ from the density in the BioOss defect.

The histological findings of the new bone tissue formed within the bone defects were measured after six months, and the results of this study showed that the percentages after six months in the BMP2 defect did not differ from the percentages in the BioOss defect.

The results of the report also converged with those of a radiographic study conducted by Kader et al. (2017),¹² who studied 16 bone defects in the maxillary socket, which were divided into two groups (a group placed within the defects bmp2 on a scaffold of hemostatic collagen sponge for bleeding and a group placed within the defect bone graft defects). The results showed that there was no statistically significant difference between the two groups after radiographic examination after 6 months.

The results of this case agreed with those of a previous study Kim et al. (2013)¹⁰ which indicated that the use of a hemostatic gelatin sponge for bleeding as a carrier of bone morphogenetic proteins when a bone defect in the radius of rabbits improves bone healing and accelerates the healing of the defects.

This report also agreed with the study done by Esfahanizadeh et al. (2019),⁶ who studied the effectiveness of using a BioOss^® bone graft within the bone defects made in the tibia of rabbits and concluded that this graft supported bone formation in some way.

The results of this research study also agreed with those of Singh et al. (2015)⁹ in their comparative study between artificial bone grafts and gelatin sponges, in which they showed that the effectiveness of the sponge is not equivalent to the effectiveness of grafts and cannot be used alone as an alternative to grafting in bone defects.

This case agreed with the results of a previous study (Carter et al., 2008)¹³ who concluded that mandibular bone defects can be successfully reconstructed using rhBMP-2-soaked sponges with and without bone marrow cells and allogenic bone.

The strength of this report lies in knowing the ability of bone-forming proteins to compete with foreign bone grafts in improving and accelerating bone healing. Also, this case was carried out on one patient and in the same jaw, which prevented the effect of the difference in the nature of healing between the upper and lower jaws or the effect of the difference in the nature of healing between people. Thus, the personal factor was neutralized.

The results of this case encourage us to repeat the comparison on several patients to increase the sample number and conclude better and scientifically more accurate results

Conclusions

It was concluded that the use of hemostatic sponges impregnated with BMP2 bone morphogenetic proteins in bone defects improved and accelerated the healing of bone defects both radiologically and histologically.

It was also concluded that the effectiveness of using this material was comparable to that resulting from the use of BioOss foreign bone graft in terms of radial density and good bone mineralization.

Consent

Written informed consent was obtained from the patient for publication of this case report and any accompanying images.