A comparative study of osseointegration of Avana implants in a demineralized freeze-dried bone alone or with platelet-rich plasma

Autologous blood products: Usage and preparation protocols

FOCUSED CLINICAL QUESTION

What are the appropriate preparation protocols for autologous blood products to support their clinical utilization?

SUMMARY

Autologous blood products provide a unique clinical benefit. Their popularity among the professions is growing. However, as this is a rapidly evolving field, multiple modalities are presented within the literature. Frequently there is no demonstrated superiority to previous iterations. This brief review attempts to offer a concise chronology on their evolution, preparation, and where possible, evidence to support their clinical utilization.

CONCLUSIONS

The field of autologous blood products is expanding rapidly. These products appear to yield variable clinical benefits in specific indications. However, evidence supporting their universal application is scant, and the superiority of one formulation versus another is yet to be demonstrated.

Comparative study of bone regeneration using fibrin sealant with xenograft in rabbit sinus: pilot study

Background

Stability of the grafted bone volume is one of the important factors to the success of alveolar bone grafts. For this, platelet-rich plasma (PRP) or fibrin sealant is mixed with the bone graft material. Bio-Oss® is a protein-free bovine mineral commonly used in bone graft procedures. The grafting particles are commonly combined with a standard fibrin sealant (Tisseel®) to fabricate a plastic implantable product. The purpose of this experiment was to evaluate the efficacy of fibrin sealant (Tisseel®) in bone regeneration performance in a rabbit maxillary sinus model.

Methods

A total of five 3.5 kg weight New Zealand white rabbits were used for the study. After elevating the sinus membrane in both maxillary sinus cavities, Bio-Oss® mixed with normal saline (group 1) was filled into the right side, and Tisseel® mixed Bio-Oss® (group 2) was inserted into the other side. The bone mineral density and bone volume were analyzed with microscopic computed tomography (micro-CT) and histomorphometric 12 weeks after application.

Results

Histologically, new bone formation rate was 14.8%, and grafted bone rate was 70.5% in group 1. In group 2, they were 18.5% and 60.4%, respectively. According to micro-CT analysis, bone mineral density (mg/cm³, BMD) was 2.5% larger in group 1.

Conclusions

The findings from this study suggest that, although the difference in the bone formation between group 1 and group 2 appears to be insignificant, group 2 had an advantage in using smaller amount of bone substances to achieve the reliable bone formation.

Immediately placed dental implants in smokers with plasma rich in growth factor versus without plasma rich in growth factor: A comparison

Introduction:

The placement of implants into fresh extraction sockets was introduced in 1970. This approach has been reviewed extensively during the past decade. Immediate postextraction implant placement is a well-accepted protocol. The concept of placement of dental implants soon after the removal of a tooth in smokers, however, is still a matter of controversy.

Purpose:

(i) To access failure rate of dental implant in smokers (ii) To evaluate added advantage of plasma rich in growth factors (PRGFs) in immediate placement of dental implants in smokers.

Materials and Methods:

The sample of 30 patients was obtained from the different Outpatient Department of Faculty of Dental Sciences; King George's Medical University, Lucknow, who had visited for rehabilitation of missing teeth by implants between April 2013 and July 2015. They were randomly divided into two groups (without use of PRGF and with use of PRGF) of 15 each. Pre- and postoperative assessment included a thorough history and clinical examination, regression of pain and swelling, implant stability by resonance frequency analysis (RFA), and implant stability according to the bone type as well as radiographic interpretation for measurement of bone loss on the mesial and distal surfaces of the implant.

Results:

In this study, pain and swelling were significantly (P < 0.05) higher in Group A than in Group B across the time interval. RFA score for implant stability was lower in Group A across the period than Group B. At the end of 3 months, RFA score (mean) in Group A was having 72.55 ISQ value, and in Group B, it was 75.71 ISQ value. In this study, postoperative crestal bone loss was more in patients in Group A as compared to patients in Group B. There was significant difference in mesial (P = 0.003) and distal (P = 0.001) crestal bone loss at 6 months between the groups.

Conclusion:

The immediate placement of dental implants in smokers with use of PRGF is shown to be efficient in relation to postoperative pain and swelling, stability, stability according to bone type, as well as bone loss.

Soft Tissue Healing and Bony Regeneration of Impacted Mandibular Third Molar Extraction Sockets, Following Postoperative Incorporation of Platelet-rich Fibrin

Introduction:

Surgical removal of impacted mandibular third molars is one of the most commonly performed dentoalveolar surgeries by dental surgeons around the globe. It is known to be associated with clinically significant postoperative morbidity including swelling, pain, trismus, fever, and infection. In addition, the residual bony defect takes 7 months to 1 year to gradually fill with bone and to reossify.

Aims and Objective:

(1) To carry out a prospective study to evaluate differences in soft tissue healing and bony regeneration of impacted mandibular third molar extraction sites, with and without the incorporation of autologous platelet-rich fibrin (PRF) within the surgical wounds. (2) To also compare the incidence of short- and long-term posttreatment complications in both cases.

Materials and Methods:

Sixty patients were randomly inducted into two groups, consisting of 30 patients each. The first group, which served as the study group, consisted of patients in whom fresh autologous PRF were placed within the extraction site immediately following the surgical removal of the impacted mandibular third molar, before suturing of the mucoperiosteal flap. The second group, which served as the control froup, included those patients in whom the mucoperiosteal flaps were closed without incorporation of PRF within site. Both groups were evaluated and compared for postoperative pain, swelling, trismus, soft tissue healing, as well as bone fill of the extraction socket.

Results:

It was found that the study group in which autologous PRF had been incorporated into the operative site exhibited quick and complication-free soft tissue healing as well as a much quicker reossification and bone fill of the extraction socket, as compared to the control group in which no PRF was used.

Conclusion:

Incorporation of PRF within extraction sockets of impacted third molars proved to be beneficial for patients, yielding a quicker postoperative recovery with fewer complications such as postoperative swelling and edema, pain, and trismus; better overall postoperative results in terms of faster soft tissue healing as well as an earlier bony regeneration.

The Dynamics in Implantation for Patients with Clefts

Objective

To investigate the stresses and strains of an endosseous dental implant in patients with different types of cleft palate in a finite element model.

Materials and Methods

Seven three-dimensional (3D) maxillary models were designed on a personal computer according to computed tomography slice data obtained from seven dry skulls. Next, computer-aided modification was performed on each model to produce three other 3D models with different cleft patterns. Thus, four model types with different cleft patterns were designed and termed NORM (without cleft), ALVEOLAR (only alveolar cleft), PALATAL (only palatal cleft), and COMPLETE (complete cleft). An implant was embedded into the molar region of each model, and a 300-N vertical load and 50-N horizontal load were applied to simulate mastication. Under these conditions, the stresses occurring at the implant-bone interface were calculated by finite element analysis.

Results

Different stress patterns were observed between the models with a palatal cleft (PALATAL and COMPLETE) and those without palatal cleft (NORM and ALVEOLAR). Regarding vertical load application, greater stresses occurred in PALATAL and COMPLETE types than in NORM and ALVEOLAR types. On application of a horizontal load, though the stresses did not show quantitative difference, their vector patterns differed.

Conclusion

In patients with palatal clefts, characteristic stress patterns occur on the bone-implant interface during mastication. This should be taken into consideration when performing an implant treatment in patients with clefts.

To evaluate the role of platelet-rich plasma in healing of acute diaphyseal fractures of the femur

PURPOSE

New research is focusing on the use of autologous growth factors to increase the effect of bone fracture healing while decreasing the amount of healing time for the patient. Platelets have been demonstrated to be the natural storage vessel for several growth factors and cytokines that promote blood coagulation, tissue repair, and the process of bone mineralization. The present study aims to evaluate the role of platelet-rich plasma (PRP) in healing of acute femoral shaft fractures radiologically. We hypothesize that it provides artificial hematoma and releases various growth factors.

METHODS

This prospective randomized study was carried out in 72 patients of traumatic fracture of the femoral shaft operated with interlocking nails (closed or open). Patients were divided into two groups: study group A (n = 33) treated with intramedullary nailing & PRP injection/gel application in the same setting; and control group B (n = 39) treated with intramedullary nailing without PRP application. Both groups were further divided into two subgroups. Study group included subgroup A1 (n = 14) operated with closed intramedullary nailing and PRP injection at the fracture site under radiological control, and subgroup A2 (n = 19) operated with open intramedullary nailing and PRP gel along with fibrin membrane application at the fracture site; while control group included subgroup B1 (n = 16) operated with closed intramedullary nailing, and subgroup B2 (n = 23) operated with open intramedullary nailing. Radiological assessment of fracture healing was done by measuring the cortex to callus ratio every month till union at 6 months.

RESULTS

Measurements of mean cortex to callus ratio revealed significant difference between the groups A & B at third and fourth months. Measurements of mean cortex to callus ratio did not reveal significant difference between the subgroups at first and sixth months. A statistically significant difference was observed between subgroups A1 & B2 and B1 & B2 at the second month; between subgroups A1 & B2, A2 & B2 and B1 & B2 at the third month; and between subgroups A1 & B2 at fourth and fifth months.

CONCLUSION

PRP has no effect on femoral shaft fracture healing treated with closed intramedullary nailing. However, PRP and matrix scaffold provided by fibrin membrane may provide an artificial hematoma effect in the initial phase of healing in open or failed closed intramedullary nailing.

Implant osseointegration in irradiated bone: an experimental study

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the effect of radiotherapy on the osseointegration of dental implants in the tibia and the action of platelet-rich plasma (PRP) as an adjuvant therapy.

MATERIAL AND METHODS

A total of 18 rabbits received two implants in each tibial epiphysis, totalizing 72 implants. The control group (group I) was composed by six rabbits and did not receive radiotherapy. The test groups (II and III) received a single dose of 1727 cGy. Group II was composed by six irradiated animals and group III by six animals that received irradiation and PRP during implant placement. The implant success rate, the bone-implant contact (BIC), and the bone volume were analyzed.

RESULTS

There was no osseointegration in four of the implants, three in group II and one in group III. Total BIC was significantly higher in group I, when compared to the other groups. There was a significant difference of osteoid BIC only between irradiated animals (group II, 8.5%; group III, 4.7%; p = 0.001). On the other hand, the mineralized BIC was significantly higher in group I. Furthermore, group II had a lower mineralized BIC than group III (p = 0.002). Bone volume was higher in the control group (41.3%), followed by group III (33.4%) and II (25.1%), with differences between groups I and II (p = 0.001) and groups II and III (p = 0.022).

CONCLUSIONS

The present study showed that both the bone volume and BIC were higher in the control group. However, the failure rates of the implants were low in both irradiated groups. The PRP was a positive adjuvant in the osseointegration process.

Influence of platelet-derived growth factor on osseous remodeling properties of a variable-thread tapered dental implant in vivo

OBJECTIVES

To evaluate the effect of platelet-derived growth factor (rhPDGF-BB) on the promotion of osteogenesis around variable-thread tapered implants in an animal model.

MATERIAL AND METHODS

Twenty-four variable-thread tapered implants were inserted in the tibia of 12 rabbits. Twelve sites received additional rhPDGF-BB released from a presoaked xenogenic bone block that was fixed supracrestally. Primary outcomes were bone-to-implant contact (BIC; in % ± SD) and percentage of medullary bone fill around the implants (PMF; in % ± SD) after 3 weeks (PDGF n = 6, no PDGF n = 6) and 6 weeks (PDGF n = 6, no PDGF n = 6).

RESULTS

Considerable crestal and medullary bone remodeling could be found around all implants. After 3 weeks, both BIC and PMF values were higher in the no PDGF group (BIC: 63% ± 10 with PDGF vs. 85% ± 5 with no PDGF; PMF: 57% ± 10 with PDGF vs. 74% ± 4 with no PDGF). After 6 weeks, the BIC difference between the two groups was less distinct (BIC: 78% ± 17 with PDGF vs. 72% ± 25 with no PDGF), whereas the PDGF group showed higher PMF values (PMF: 77% ± 5 with PDGF vs. 56% ± 10 with no PDGF).

CONCLUSIONS

The addition of rhPDGF-BB decreases early osseous crestal and medullar healing properties around dental implants. In a later phase, an increase in the cortical area as well as an increased medullar bone formation was seen. This response is likely to provide stronger secondary stability and stability in suboptimal situations involving poor-quality bone.

A randomized comparative prospective study of platelet-rich plasma, platelet-rich fibrin, and hydroxyapatite as a graft material for mandibular third molar extraction socket healing

AIM

The purpose of this study was to compare the efficacy of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and hydroxyapatite (HA) for reduction of pain and swelling, absence of dry socket, soft tissue healing, and bone regeneration after mandibular third molar extraction in human patients.

MATERIALS AND METHODS

Forty patients requiring extraction of mandibular third molars were randomly grouped as control, PRP, PRF, and HA-treated. The patients were assessed for postoperative pain, swelling, dry socket, and soft tissue healing on the 3^rd, 7^th, and 14^th day of postoperative periods depending on the standard methods. Radiological assessment of the extraction site was done at 1, 2, and 6 months interval to compare the change in bone density in the sockets in control and treated patients.

RESULTS

Pain and swelling were less on PRP and PRF site when compared to HA and control site. PRP and PRF site showed better soft tissue healing when compared to HA and control site. Radiographic assessment showed comparatively lesser bone density values in PRP, PRF, and control site at 1, 2, and 6 months than HA site.

CONCLUSION

Our study showed that PRP and PRF are better graft materials than HA regarding pain, swelling, dry socket, and soft tissue healing. Bone regeneration is induced promptly by HA as compared to other graft materials. However, a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding the efficacy of the graft materials.

Mandibular Third Molar Extraction Wound Healing With and Without Platelet Rich Plasma: A Comparative Prospective Study

AIMS

To evaluate the efficacy of autologous platelet rich plasma (PRP) in regeneration of bone and to assess clinical compatibility of the material in mandibular third molar extraction socket.

OBJECTIVE OF THE STUDY

To compare the healing of mandibular third molar extraction wounds with and without PRP.

MATERIALS AND METHODS

Group A consists of the 30 patients where PRP will be placed in the extraction socket before closure of the socket. Group B consists of 30 patients who will be the control group where the extraction sockets will be closed without any intra socket medicaments. The patients would be allocated to the groups randomly.

RESULTS

Soft tissue healing was better in study site compared to control site. The result of the study shows rapid bone regeneration in the extraction socket treated with PRP when compared with the socket without PRP. Evaluation for bone blending and trabecular bone formation started earlier in PRP site compared to control, non PRP site. Also there was less postoperative discomfort on the PRP treated side.

CONCLUSION

Autologous PRP is biocompatible and has significant improved soft tissue healing, bone regeneration and increase in bone density in extraction sockets.

Effect of Platelet-Rich Plasma on the Healing of Mandibular Defects Treated With Fresh Frozen Bone Allograft: A Radiographic Study in Dogs

The purpose of this study was to radiographically analyze the effect of autologous platelet rich plasma (PRP) on the healing of fresh frozen bone allograft (FFBA) placed in surgically created resection defects in mandibles of dogs. Bilateral resection defects measuring 1.5 cm × 1 cm were surgically created on the inferior border of the mandible in 10 adult male dogs. The defects were randomly divided into three groups: C, FFBA, and FFBA/PRP. In Group C, the defect was filled by blood clot only. In Group FFBA, the defect was filled with particulate fresh frozen bone allograft. In Group FFBA/PRP, it was filled with particulate fresh frozen bone allograft combined with PRP. At 90 days postoperative, standardized radiographs of the mandibles were obtained and results were quantitatively evaluated. Analysis of digitized radiographs indicated that non-PRP grafts were significantly less dense than the PRP grafts. Group FFBA/PRP also presented a statistically greater mineralized tissue area than Groups C and FFBA. Within the limits of this study, it can be concluded that PRP enhanced the healing of FFBA in resection defects in mandibles of dogs.

Role of platelet rich fibrin and platelet rich plasma in wound healing of extracted third molar sockets: a comparative study

AIMS AND OBJECTIVES

This prospective study was done to evaluate and compare the utility and effectiveness of platelet rich fibrin (PRF) with that of platelet rich plasma (PRP) on soft tissue healing and bone tissue healing of extracted third molar sockets.

MATERIALS AND METHODS

This study included split mouths of 20 patients who underwent bilateral extraction of impacted third molars. During the same appointment, following which PRF and PRP were prepared from patients' autologous blood and placed in right and left extracted sockets, respectively. The data for soft tissue healing were recorded at end of 1 week, using healing index of Landry et al. and the data for bone tissue healing were recorded at the end of 4 months using digitalized orthopantomogram images on Adobe Photoshop CS; which was then compared between the two sites of the same patient.

RESULTS

The mean values of soft tissue healing collected at 1 week post-operative, for PRF group were significantly higher as compared to PRP group. And the mean values of bone density collected at the end of fourth month post-operative, for PRF group were also significantly higher as compared to PRP group. Both tests showed p value of 0.00.

CONCLUSION

PRF is significantly better in promoting soft tissue healing and also faster regeneration of bone after third molar extraction, in comparison with PRP. This could be attributed to simpler preparation protocols of PRF over PRP and the ability of PRF to release growth factors in a controlled way.

Demineralized bone matrix and platelet-rich plasma do not improve healing of osteochondral defects of the talus: an experimental goat study

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of demineralized bone matrix (DBM) with and without platelet-rich plasma (PRP) in the treatment of osteochondral defects (OCDs) of the talus. We hypothesized that treatment with DBM would result in more bone formation than no treatment in control OCDs, and that PRP would further enhance the regenerative capacity of DBM.

METHOD

A standardized 6-mm OCD was created in each talus of 16 adult goats. According to a randomization scheme, one OCD of each goat was treated with allogeneic DBM hydrated with normal saline (n = 8) or hydrated with autologous PRP (n = 8). The contralateral OCD (n = 16) served as control. After 24 weeks, the animals were euthanized and the tali excised. Various outcome parameters were analyzed with use of macroscopic evaluation, micro-computed tomography (μCT), histology, histomorphometry, and fluorescence microscopy.

RESULTS

None of the analyses revealed statistically significant differences between the groups for any of the parameters analyzed in any volume of interest. For example, the mean bone volume fraction (BV/TV) of the defect, as measured by μCT, was 0.56 (95% confidence interval [CI], 0.44-0.68) for DBM hydrated with normal saline and 0.52 (95% CI, 0.40-0.65) for DBM hydrated with PRP, compared to 0.53 (95% CI, 0.45-0.61) and 0.54 (95% CI, 0.44-0.64) for the internal controls, respectively (P > 0.05).

CONCLUSION

In contrast to our hypotheses, no beneficial treatment effect of DBM with or without PRP was found for OCDs of the caprine talus.

Experimental study of the effect of autologous platelet-rich plasma on the early phases of osteoinduction by allogenic demineralized bone matrix

PURPOSE

To evaluate the effect of autologous platelet-rich plasma (PRP) on the early phases of osteoinduction by allogenic demineralized bone matrix (DBM) in rabbit intramuscular positions.

MATERIALS AND METHODS

Allogenic DBM was produced from bones of 3 healthy rabbits. In each of 6 experimental animals, 0.3 mL autologous PRP was prepared and 2 muscle pouches were created, where 250 mg DBM + PRP (experimental sites) and 250 mg DBM without PRP (control sites) were randomly implanted. Animals were euthanized 3 weeks postoperatively.

RESULTS

Histologic examination revealed uneventful healing in all cases, whereas remineralization of the periphery of the bone graft particles was a constant finding. In both control and experimental sites, fibroblasts and other mesenchymal cells (probably osteoprogenitor cells and preosteoblasts) were observed. The main histological difference was the recolonization of the empty lacunae of the bone graft particles by osteocytes at the control sites. The degradation of the graft at the control sites was statistically significantly quicker, although a statistically significant difference regarding the amount of the newly formed fibrous connective tissue was not observed.

CONCLUSION

The present study demonstrated that in this experimental model, the addition of PRP to DBM had a negative effect on the early phases of osteoinduction at 3 weeks of observation.

Histologic Evaluation of Osseous Regeneration Following Combination Therapy With Platelet-Rich Plasma and Bio-Oss in a Rat Calvarial Critical-Size Defect Model

Platelet-rich plasma (PRP) is an autogenous source of growth factors shown to facilitate human bone growth. Bio-Oss, an osteoconductive xenograft, is used clinically to regenerate periodontal defects, restore dental alveolar ridges, and facilitate sinus-lift procedures. The purpose of this study was to analyze whether a combination of PRP and Bio-Oss would enhance bone regeneration better than either material alone. PRP and/or Bio-Oss were administered in an 8-mm critical-size defect (CSD) rat calvarial model of bone defect between 2 polytetrafluoroethylene membranes to prevent soft tissue incursion. Eight weeks after the induction of the CSD, histologic sections were stained with hematoxylin and eosin stain and analyzed via light microscopy. Qualitative analyses revealed new bone regeneration in all 4 groups. The Bio-Oss and PRP plus Bio-Oss groups demonstrated greater areas of closure in the defects than the control or PRP-only groups because of the space-maintaining ability of Bio-Oss. The groups grafted with Bio-Oss showed close contact with new bone growth throughout the defects, suggesting a stronger graft. The use of PRP alone or in combination with Bio-Oss, however, did not appear to enhance osseous regeneration at 8 weeks. Areas grafted with Bio-Oss demonstrated greater space-maintaining capacity than controls, and PRP was an effective vehicle for placement of the Bio-Oss. However, at 8 weeks this study was unable to demonstrate a significant advantage of using PRP plus Bio-Oss over using Bio-Oss alone.

A comparative study of the regenerative effect of sinus bone grafting with platelet-rich fibrin-mixed Bio-Oss® and commercial fibrin-mixed Bio-Oss®: an experimental study

Anorganic bovine bone (Bio-Oss®) particles are one of the most popular grafting materials. The particles are often mixed with platelet-rich fibrin (PRF) or a commercial fibrin (Tisseel®) to form a mouldable graft material. The objective of this study was to compare the potentials of PRF-mixed Bio-Oss® and Tisseel®-mixed Bio-Oss® to enhance bone regeneration in a canine sinus model. Six mongrel dogs were used in this study. After elevating the sinus membrane in both maxillary sinus cavities, an implant was placed into the sinus cavity. In one of the sinus cavities, the PRF/Bio-Oss® composite was grafted, and the Tisseel®/Bio-Oss® composite was grafted in the other sinus cavity. After a 6 month healing period, bone formation in the graft sites and bone-implant contact were evaluated. The mean osseointegration rate was 43.5 ± 12.4% and new bone formation rate 41.8 ± 5.9% in the PRF/Bio-Oss® composite sites. In the Tisseel®/Bio-Oss® composite sites they were 30.7 ± 7.9% and 31.3 ± 6.4%. There were statistically significant differences between the groups. The findings from this study suggest that when platelet-rich fibrin is used as an adjunct to Bio-Oss® particles for bone augmentation in the maxillary sinus, bone formation in the graft sites is significantly greater than when Tisseel® is used.

Systematic review of pre-clinical models assessing implant integration in locally compromised sites and/or systemically compromised animals

OBJECTIVE

The aim was to systematically search the dental literature for pre-clinical models assessing implant integration in locally compromised sites (part 1) and systemically compromised animals (part 2), and to evaluate the quality of reporting of included publications.

METHODS

A Medline search (1966-2011) was performed, complimented by additional hand searching. The quality of reporting of the included publications was evaluated using the 20 items of the ARRIVE (Animals in Research In Vivo Experiments) guidelines.

RESULTS

One-hundred and seventy-six (part 1; mean ARRIVE score = 15.6 ± 2.4) and 104 (part 2; 16.2 ± 1.9) studies met the inclusion criteria. The overall mean score for all included studies amounted to 15.8 ± 2.2. Housing (38.3%), allocation of animals (37.9%), numbers analysed (50%) and adverse events (51.4%) of the ARRIVE guidelines were the least reported. Statistically significant differences in mean ARRIVE scores were found depending on the publication date (p < 0.05), with the highest score of 16.7 ± 1.6 for studies published within the last 2 years.

CONCLUSIONS

A large number of studies met the inclusion criteria. The ARRIVE scores revealed heterogeneity and missing information for selected items in more than 50% of the publications. The quality of reporting shifted towards better-reported pre-clinical trials within recent years.

Effect of plasma-rich in platelet-derived growth factors on peri-implant bone healing: An experimental study in canines

BACKGROUND

Tissue engineering principles can be exploited to enhance alveolar and peri-implant bone reconstruction by applying such biological factors as platelet-derived growth factors. The objective of the present study is to investigate the effect of autologous plasma-rich in growth factors (on the healing of peri-implant bone in canine mandible).

MATERIALS AND METHODS

In this prospective experimental animal study, two healthy canines of the Iranian mix breed were selected. Three months after removing their premolar teeth on both sides of the mandible, 12 implants of the Osteo Implant Corporationsystem, 5 mm in diameter and 10 mm in length, were selected to be implanted. Plasma rich in growth factors (PRGF) were applied on six implants while the other six were used as plain implants without the plasma. The implants were installed in osteotomy sites on both sides of the mandible to be removed after 4 weeks with the surrounding bones using a trephine bur. Mesio-distal sections and implant blocks, 50 μ in diameter containing the peri-implant bone, were prepared By basic fuchin toluidine-bluefor histological and histomorphometric evaluation by optical microscope. The data were analyzed using Mann-Whitney Test (P<0.05).

RESULTS

The bone trabeculae and the type of bone generation in PRGF and control groups had no statistically significant differences (P=0.261, P=0.2) although the parameters showed higher measured values in the PRGF group. However, compared to the control, application of PRGF had significantly increased bone-to-implant contact (P=0.028)

CONCLUSION

Based on the results, it may be concluded that application of PRGF on the surface of implant may enhance bone-to-implant contact.

Efficacy of platelet-rich plasma combined with allograft bone in the management of displaced intra-articular calcaneal fractures: a prospective cohort study

To investigate whether platelet-rich plasma (PRP) when used with allograft bone improves the management outcome of displaced intra-articular calcaneal fractures. Over a 7-year period, all displaced type III calcaneal fractures admitted in our department (276 fractures in 254 patients) were randomly divided into three groups according to the plan of management: autograft alone (n = 101), allograft combined with PRP (n = 85), or allograft alone (n = 90). Radiographic imaging and three-dimensional computed tomography were used to assess the thalamic portion, Bohler's angle, the crucial angle of Gissane, and the height, width and length of the calcaneum. The American Orthopedic Foot and Ankle Society (AOFAS) ankle-hind-foot scoring system was used to evaluate the hind foot function at 12, 24, and 72 months postsurgery. At 12 months no significant difference existed in outcome amongst the treatment groups (p > 0.05). However, at 24 and 72 months the results of the autograft, and the allograft combined with PRP, were similar and both were significantly better than that of the allograft alone (p < 0.05). PRP augmented the favorable outcome of allografts in the management of displaced calcaneal fractures, and matched that of autograft used alone. The findings of this study thus support the clinical use of PRP in conjunction with allograft in the treatment of displaced intra-articular calcaneal fractures.

Histological evaluation of bone healing using organic bovine bone in combination with platelet-rich plasma (an experimental study on rabbits)

OBJECTIVES

This study was carried out to histologically assess the effect of bone grafting materials extracted from bovine origin on the bone healing process either alone or when mixed with autologous platelet-rich plasma which could be used in many procedures of oral and maxillofacial bone and implant reconstructive surgery.

MATERIALS AND METHODS

Sixteen rabbits were used; three intrabony defects in the femur bone of each rabbit were created, one left unfilled for normal healing process and served as control, the second filled with xenogenic graft (Gen-Ox-lyophilized bovine bone organic matrix), and the third filled with (Gen-Ox-lyophilized bovine bone organic matrix) mixed with autologous platelet-rich plasma. Histological examination of the sections was performed after staining with H&E and Van Geison stains. The histomorphometric analysis including counting of bone cells (osteoblasts, osteocytes, and osteoclasts) with performance of osteon diameter and lamellar thickness at the end of the fourth week postoperatively was obtained.

RESULTS

It has been shown that with the use of autologous platelet-rich plasma in combination with the xenogenic bone graft prepared from bovine origin, new bone formation and neovascularization were enhanced significantly when compared with xenogenic graft alone.

CONCLUSION

The addition of PRP to xenogenic bone substitute in small bone defects of the rabbit femur showed a histomorphometric increase in bone formation (at the fourth week of healing).

CLINICAL RELEVANCE

Platelet concentrate might be used to accelerate the osseointegration of enosseous dental implants.

Human platelet rich plasma plus Persian Gulf coral effects on experimental bone healing in rabbit model: radiological, histological, macroscopical and biomechanical evaluation

Coral is an osteoconductive material used as a bone graft extender and human platelet rich plasma has been used as a source of osteoinductive factor. A combination of human platelet rich plasma and coral is expected to create a composite with both osteoconductive and osteoinductive properties. This study examined the effect of a combination of human platelet rich plasma and coral on osteogenesis in vivo using rabbit model of bone healing. A critical size defect of 10 mm elongation was created in the radial diaphysis of 36 rabbit and either supplied with coral-human PRP, or coral alone or left empty (control group). The platelets in the PRP were about 10.1 fold compared to normal blood. Radiographs of each forelimb was taken postoperatively on 1st day and then at the 2nd, 4th, 6th and 8th weeks post injury to evaluate bone formation, union and remodeling of the defect. The operated radiuses were removed on 56th postoperative day and were grossly and histopathologically evaluated. In addition, biomechanical test was conducted on the operated and normal forearms of the rabbits. This study demonstrated that coral-human PRP (hPRP), could promote bone regeneration in critical size defects with a high regenerative capacity. The results of the present study demonstrated that coral-hPRP could be an attractive alternative for reconstruction of the major diaphyseal defects of the long bones in animal models.

The effect of hydroxyapatite-hPRP, and coral-hPRP on bone healing in rabbits: radiological, biomechanical, macroscopic and histopathologic evaluation

There is a continuing search for bone substitutes to avoid or minimize the need for autogenous bone grafts. Human platelet-rich plasma (hPRP) is used to stimulate bone formation in vivo. Hydroxyapatite, a crystalline phase of calcium phosphate found naturally in bone minerals, has shown tremendous promise as a graft material. Coral is an osteoconductive material used as a bone graft extender. This study examined the effect of human platelet-rich plasma in combination with hydroxyapatite and coral on osteogenesis in vivo using rabbit model bone healing. A critical size defect of 10 mm elongation was created in the radial diaphysis of 36 rabbit and either supplied with human platelet-rich plasma (12 rabbits), and in combination with hydroxyapatite (12 rabbits), or coral (12 rabbits). Radiographs of each forelimb were taken postoperatively on 1st day and then at the 2nd, 4th, 6th and 8th weeks post injury to evaluate bone defect healing. The operated radiuses were removed on the 56th postoperative day and were grossly and histopathologically evaluated. In addition, biomechanical test was conducted on the operated and normal forearms of another half of the rabbits in each group. This study demonstrated that high concentrations of xenogenic platelets lead to superior and faster bone formation in comparison with hydroxyapatite-hPRP and coral-hPRP. Hydroxyapatite-hPRP and coral-hPRP resulted to almost similar results in bone healing process at this stage.

Effects of combined hydroxyapatite and human platelet rich plasma on bone healing in rabbit model: radiological, macroscopical, hidtopathological and biomechanical evaluation

Hydroxyapatite is an osteoconductive material used as a bone graft extender and exhibits excellent biocompatibility with soft tissues such as skin, muscle and gums, making it an ideal candidate for orthopedic and dental implants or components of implants. Synthetic hydroxyapatite has been widely used in repair of hard tissues, and common uses include bone repair, bone augmentation, as well as coating of implants or acting as fillers in bone or teeth. On the other hand, human platelet rich plasma (hPRP) has been used as a source of osteoinductive factor. A combination of hPRP and hydroxyapatite is expected to create a composite with both osteoconductive and osteoinductive properties. This study examined the effect of a combination of hydroxyapatite and hPRP on osteogenesis in vivo, using rabbit model bone healing. A critical size defect of 10 mm long was created in the radial diaphysis of 36 rabbit and either supplied with hydroxyapatite-human PRP or hydroxyapatite or was left empty (control group). Radiographs of each forelimb were taken postoperatively on 1st day and then at the 2nd, 4th, 6th and 8th weeks post injury to evaluate bone formation, union and remodeling of the defect. The operated radiuses of half of the animals in each group were removed on 56th postoperative day and were grossly and histopathologically evaluated. In addition, biomechanical test was conducted on the operated and normal forearms of the other half of the animals of each group. This study demonstrated that hydroxyapatite-humanPRP, could promote bone regeneration in critical size defects with a high regenerative capacity. The results of the present study demonstrated that hydroxyapatite-hPRP could be an attractive alternative for reconstruction of the major diaphyseal defects of the long bones in animal models.

Healing of fresh frozen bone allograft with or without platelet-rich plasma: a histologic and histometric study in rats

PURPOSE

This study histomorphometrically analyzed the effect of autogenous platelet-rich plasma (PRP) on healing of fresh frozen bone allograft (FFBA) in bony defects in rat calvaria.

MATERIALS AND METHODS

A 5mm-diameter defect was created in the calvarium of 30 rats. Animals were divided into three groups: C (defect was filled by blood clot only), FFBA (defect was filled with 0.01mL of FFBA), and FFBA/PRP (defect was filled with 0.01mL of FFBA combined with 100µL of PRP). All animals were euthanized at 30 days postoperatively. Histomorphometry and histology analyses were performed. Data were statistically analyzed (analysis of variance, Tukey, p<.05).

RESULTS

FFBA had a statistically smaller new bone area than groups FFBA/PRP and C. No statistically significant differences were observed between groups FFBA and FFBA/PRP with regard to remaining bone graft particle area.

CONCLUSION

It can be concluded that (1) PRP improved the incorporation of FFBA, increasing the amount of new bone formed; (2) PRP has not influenced the resorption of nonviable particles of the FFBA; and (3) presence of remaining FFBA particles might have accounted for the smaller amount of new bone observed in group FFBA when compared with control group.

Bone grafts in craniofacial surgery

Reconstruction of cranial and maxillofacial defects is a challenging task. The standard reconstruction method has been bone grafting. In this review, we shall describe the biological principles of bone graft healing, as pertinent to craniofacial reconstruction. Different types and sources of bone grafts will be discussed, as well as new methods of bone defect reconstruction.

Treatment of endodontically induced periapical lesions using hydroxyapatite, platelet-rich plasma, and a combination of both: An in vivo study

Aim and Objectives:

To evaluate bone regeneration in endodontically induced periapical lesions using Hydroxyapatite, Platelet-Rich Plasma (PRP), and a combination of Hydroxyapatite and Platelet-Rich Plasma for a period of one year.

Materials and Methods:

Twenty systemically healthy patients of both genders between the ages 20 and 40 years were included. To qualify, the patient had to have a tooth where non-surgical root canal therapy had failed, periapical radiolucency was present, and periapical root end surgery was required. The bony defect had to be confined to the apical area, with the bone covering the entire root surface coronally, with an intact lingual cortical plate. Patients were randomly divided into four groups, with five patients each, as follows: Group I — Replacement with Hydroxyapatite, Group II — Replacement with PRP, Group III — Replacement with PRP and Hydroxyapatite, and Group IV — Control group with no substitutes. The patients were evaluated both clinically and radiographically.

Results:

The radiographic evaluation revealed that Group I patients showed complete bone regeneration with evidence of a trabecular pattern, at the end of one year, Group II patients showed complete bone regeneration at the end of nine months, Group III patients showed complete bone regeneration at the end of six months, and Group IV patients showed bone regeneration, which was not satisfactory even after one year.

Conclusions:

The PRP and Hydroxyapatite combination facilitated better and faster bone regeneration when compared to PRP alone.

Investigation of peri-implant bone healing using autologous plasma rich in growth factors in the canine mandible after 12 weeks: a pilot study

Introduction:

Faster reconstruction of patients’ masticatory systems is the aim of modern dentistry. A number of studies have indicated that application of growth factors to the surface of a dental implant leads to accelerated and enhanced osseointegration. The objective of the present study was to investigate the effect of plasma rich in growth factors on peri-implant bone healing.

Materials and Methods:

For the purpose of this study, two healthy, mixed-breed canines were selected, and the premolars were extracted from both sides of the mandible. Three months after premolar removal, 12 implants, each 5 mm in diameter and 10 mm in length, were placed in osteotomy sites on both sides of the mandible. Prior to placement, plasma rich in growth factors was applied to the surfaces of six implants, while the other six were used without plasma rich in growth factors. The implants were removed after 12 weeks along with the bone surrounding the sites using a trephine bur. One mesiodistal section containing the surrounding bone from each implant block, 50 µm in diameter, was prepared for histologic and histomorphometric investigation with an optical microscope.

Results:

The sites with implants treated with plasma rich in growth factors showed more bone-to-implant contact compared to control sites. Also, higher values for bone trabecular thickness and bone maturity were recorded for the PRGF-treated sites than for the control sites.

Conclusion:

Application of plasma rich in growth factors to the surface of an implant may enhance the bone healing process as well as bone-to-implant contact, thereby helping to achieve faster osseointegration.

Bovine Anorganic Bone Graft Associated with Platelet-Rich Plasma: Histologic Analysis in Rabbit Calvaria

Autogenous bone tissue has regeneration potential; however, this capacity may not be sufficient in larger bone defects. The aim of this study is to histologically evaluate anorganic bovine bone grafts (GenOx Inorg) with or without platelet-rich plasma (PRP). Two bone lesions were created in calvaria of 12 rabbits. The 24 surgical lesions were separated into 3 groups: coagulous, anorganic, and anorganic with PRP. At the 4-week time point, the animals were euthanized and the grafted area removed, fixed in formalin 10% with phosphate buffered saline, 0.1 M, and embedded in paraffin. The histologic parameters analyzed were new bone filling the defect area, presence of giant cells and particles of the graft, and new bone formation associated with the particles. In the coagulous group, defects were filled with fibrous tissue that attached the periosteum and little bone neoformation in the periphery. In anorganic groups with or without PRP, little new bone formation in the periphery of the defect was observed; however, in the center of some defects there was new bone. Moderate presence of giant cells and little new bone formation was associated with the innumerous graft particles. Histologic results revealed no statistically significant differences among the defects new bone fill between the studied groups (P  =  .64). There was no significant difference in the number of giant cells (P  =  .60), graft particles (P  =  .46), and new bone formation around graft particles (P  =  .26), whether PRP was added or not. Anorganic bone, isolated or mixed with PRP, was biocompatible and osteoconductive, while maintaining bone volume.

Influence of platelet-rich plasma on the histologic characteristics of the autologous fat graft to the upper lip of rabbits

BACKGROUND

This study evaluated the influence of platelet-rich plasma (PRP) on the histologic characteristics of autologous fat grafts to the upper lip of rabbits.

METHODS

Nine New Zealand white rabbits were used. Eight of the rabbits underwent fat harvest from the groin fat pads using a modified Coleman technique. One side of the upper lip was infiltrated with autologous fat and the other side with fat and PRP. Four of the infiltrated rabbits were killed 8 weeks after the lip augmentation, and the remaining four infiltrated rabbits plus one control case were killed 12 weeks after the procedure. Coronal sections of both upper lips were analyzed microscopically to evaluate the quality of the fat graft, the inflammatory reaction, the presence of oil cysts, the degree of fibrosis, and the neovascularization.

RESULTS

The infiltration of adipose tissue plus PRP presented less inflammatory reaction (p < 0.05) and fewer oil cysts (p < 0.05) than the infiltration of adipose tissue without PRP.

CONCLUSIONS

The infiltration of fat tissue plus PRP generates a lower inflammatory reaction and less formation of oil cysts than the infiltration of isolated fat. Platelet-rich plasma increases the maintenance of the transplanted fat cells.

Comparative radiographic evaluation of alveolar bone healing associated with autologous platelet-rich plasma after impacted mandibular third molar surgery

PURPOSE

This study radiographically evaluated the performance of autologous platelet-rich plasma (PRP) applied in tooth sockets.

PATIENTS AND METHODS

Thirty extractions of bilateral impacted mandibular third molars were performed in 15 volunteers (7 men, 8 women; 18 to 22 years old). After extraction of right and left mandibular third molars, the socket at 1 side received the autologous PRP (PRP group) and the other was filled with blood clot (control group). Millimeter periapical radiographs were obtained 7 days, 1 month, and 2, 3, and 6 months postoperatively. Radiographic bone density was quantified 3 times by the same examiner at different moments using HLImage 97 software, and data were statistically analyzed by Statgraf 7.0 software (analysis of variance and Tukey test).

RESULTS

In general, there was significantly faster bone formation in sockets treated with PRP (P < .01). Significant bone formation was observed in the first month (P < .01), second month (P < .05), and third month (P < .01) for the PRP group. No statistical differences were observed on the seventh day and sixth month of investigation, yet there were higher means of radiographic bone density in sockets treated with PRP. In the control group, men exhibited significant bone repair compared with women (P < .05).

CONCLUSION

Autologous PRP was found to accelerate alveolar bone regeneration, and men presented better repair after tooth extraction.

Efficacy of platelet rich plasma in sinus lift augmentation

The present study aims to evaluate and analyze the efficacy of Platelet Rich Plasma (PRP) with hydroxyapatite crystals for maxillary sinus augmentation procedures. A comparative study of 10 patients with a mean average age of 35 years with less than 5 mm of residual alveolar bone was conducted. Six patients underwent Lateral sinus lift procedure with allografts (platelet rich plasma and hydroxyappatite crystals) and four patients underwent the same procedure but with autografts (symphyseal). Follow-up for a period of 3 years was done. The patients were assessed for postoperative pain, sinusitis, oro-antral communication, epistaxis, graft rejection, infection and potential loss of bone and teeth. During the 3 years period of follow-up there were no complications recorded. A mean post-operative augmented height of 15 mm was achieved in all the patients. Maxillary sinus lift procedure using a mixture of hydroxyapatite crystals and platelet rich plasma was found to be very effective in increasing the height of residual alveolar bone when compared to the use of autografts alone.

Platelet autologous growth factors decrease the osteochondral regeneration capability of a collagen-hydroxyapatite scaffold in a sheep model

Background

Current research aims to develop innovative approaches to improve chondral and osteochondral regeneration. The objective of this study was to investigate the regenerative potential of platelet-rich plasma (PRP) to enhance the repair process of a collagen-hydroxyapatite scaffold in osteochondral defects in a sheep model.

Methods

PRP was added to a new, multi-layer gradient, nanocomposite scaffold that was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles. Twenty-four osteochondral lesions were created in sheep femoral condyles. The animals were randomised to three treatment groups: scaffold, scaffold loaded with autologous PRP, and empty defect (control). The animals were sacrificed and evaluated six months after surgery.

Results

Gross evaluation and histology of the specimens showed good integration of the chondral surface in both treatment groups. Significantly better bone regeneration and cartilage surface reconstruction were observed in the group treated with the scaffold alone. Incomplete bone regeneration and irregular cartilage surface integration were observed in the group treated with the scaffold where PRP was added. In the control group, no bone and cartilage defect healing occurred; defects were filled with fibrous tissue. Quantitative macroscopic and histological score evaluations confirmed the qualitative trends observed.

Conclusions

The hydroxyapatite-collagen scaffold enhanced osteochondral lesion repair, but the combination with platelet growth factors did not have an additive effect; on the contrary, PRP administration had a negative effect on the results obtained by disturbing the regenerative process. In the scaffold + PRP group, highly amorphous cartilaginous repair tissue and poorly spatially organised underlying bone tissue were found.

A comparison of bone generation capability in rabbits using tooth ash and plaster of Paris with platelet-rich plasma or fibrin sealant

OBJECTIVES

Increased attention has been focused on determining the most efficacious materials for generalized bone grafts. This article presents the results of a histomorphometric analysis of bone healing in the calvaria of rabbits. The study compared the use of a tooth ash and plaster of Paris mixture alone, in association with platelet-rich plasma (PRP), and in association with fibrin sealant.

STUDY DESIGN

Twelve rabbits were divided into control (group 1) and experimental groups (groups 2, 3, and 4). Group 1 was maintained as an unfilled control, and tooth ash and plaster of Paris were used in group 2, tooth ash and plaster of Paris with PRP were used in group 3, and tooth ash and plaster of Paris with fibrin sealant (Tissucol Duo Quick) were used in group 4. One-half of the animals were killed after 4 weeks, and the rest were killed after 8 weeks. Bone samples were taken from the defect areas, and newly formed bone was analyzed histomorphometrically.

RESULTS

The rate of new bone formation in groups 2, 3, and 4 was significantly higher than the rate in the control group. The rate of new bone formation in groups 3 and 4 was higher than the rate in group 2, but the difference was not statistically significant.

CONCLUSION

The concomitant use of PRP or fibrin sealant with tooth ash and plaster of Paris graft materials may have a positive effect on bone healing.

Transmucosal healing around peri-implant defects: crestal and subcrestal implant placement in dogs

OBJECTIVE

This study was designed to evaluate the transmucosal healing response of implants placed with the junction of the smooth surfaces, either crestal or subcrestal, into simulated extraction defects after healing periods of 1 and 3 months.

MATERIALS AND METHODS

A total of 23 Straumann SP v3.3 mm NN, SLA 10 mm implants were placed in the mandibular premolar regions of three greyhound dogs 3 months after the teeth were removed. Five control implants were placed at the crestal bone level, and test implants with surgically created peri-implant defects of 1.25 mm wide x 5 mm depth were placed either at the crestal (nine implants) or at the 2 mm subcrestal (nine implants) bone level. Implants on the right side were placed 1 month before the dogs were sacrificed, and implants on the left side were placed 3 months before sacrifice. All dogs had daily plaque control following surgery and were sacrificed 3 months after implant placement for histological and histometric analyses.

RESULTS

Mesial-distal ground sections of the control and test implant specimens showed a greater %BIC in the coronal defect region after 3 months of healing. This healing response was incomplete for the test implants compared with the control implants after a 1-month healing period. The histometric measurements for test implants placed at the crestal bone level or 2 mm subcrestal with surgically created peri-implant defects were more coronal or closer to the implant margin compared with the control implants. Additionally, the degree of osseointegration between the newly formed bone and the implant surface was similar between the test implants.

CONCLUSION

Peri-implant defects of 1.25 mm width healed with spontaneous bone regeneration around implants placed transmucosally at crestal or 2 mm subcrestal with a high degree of osseointegration after a 3-month healing period.

Potential for osseous regeneration of platelet rich plasma: a comparitive study in mandibular third molar sockets

PURPOSE

To evaluate the efficacy of autologous platelet-rich plasma in soft tissue healing & bone regeneration in mandibular third molar extraction socket.

METHODS

The study was conducted in 10 patients visiting the outpatient Department of Oral & Maxillofacial Surgery, requiring extraction of bilateral mandibular third molars. Following extraction, autologous Platelet Rich Plasma (PRP) was placed in one extraction socket, the other socket was studied as the control site with no PRP. The patients were assessed for postoperative pain, soft tissue healing, bone blending and trabecular formation. Radiological assessment of the extraction site was done for a period of 4 months to evaluate the change in bone density.

RESULTS

Pain was less in the study site compared to control site, soft tissue healing was better in study site. Evaluation for bone blending and trabecular bone formation started earlier in PRP site compared to control, non PRP site. The evaluation of bone density by radiological assessment showed the grey level values calculated after 4 months at the PRP site were comparatively higher than the average baseline value of bone density at extraction site in control site.

CONCLUSION

The study showed that autologous PRP is biocompatible and has significantly improved soft tissue healing, bone regeneration and increase in bone density in extraction sockets. However a more elaborate study with a larger number of clinical cases is essential to be more conclusive regarding its efficacy.

Comparison of mesenchymal stem cells from bone marrow and adipose tissue for bone regeneration in a critical size defect of the sheep tibia and the influence of platelet-rich plasma

Aim of the present study was to compare the osteogenic potential of bone marrow derived mesenchymal stem cells (BMSC) and adipose-tissue derived stem cells (ASC) and to evaluate the influence of platelet-rich plasma (PRP) on the osteogenic capacity of ASC in a large animal model. Ovine BMSC (BMSC-group) and ASC (ASC-group) were seeded on mineralized collagen sponges and implanted into a critical size defect of the sheep tibia (n=5 each). In an additional group, platelet-rich plasma (PRP) was used in combination with ASC (PRP-group). Unloaded mineralized collagen (EMPTY-group) served as control (n=5 each). Radiographic evaluation was performed every 2 weeks, after 26 weeks histological analysis was performed. Radiographic evaluation revealed a significantly higher amount of newly formed bone in the BMSC-group compared to the ASC-group at week 10 and compared to EMPTY-group from week 12 (all p<0.05). A superiority on radiographic level concerning bone formation of the PRP-group versus the empty control group was found (p<0.05), but not for the ASC-group. Histological analysis confirmed radiographic evaluation finding analogous significances. In conclusion, ASC seem to be inferior to BMSC in terms of their osteogenic potential but that can partially be compensated by the addition of PRP.

A combination graft of low-molecular-weight silk fibroin with Choukroun platelet-rich fibrin for rabbit calvarial defect

OBJECTIVE

The objective of this study was to determine the capabilities of silk fibroin as a biomaterial template for bone formation when mixed with Choukroun platelet-rich fibrin (PRF) in vivo.

STUDY DESIGN

Ten New Zealand white rabbits were used for this study and bilateral round shaped defects were formed in the parietal bone (diameter 9.0 mm). The silk fibroin was digested by acid and made into powder (molecular weight <1.0 kDa). The right side (experimental group) received the silk fibroin plus platelet-rich fibroin and the left side (control group) did not receive a graft. Animals were killed at 6 weeks and 12 weeks. The specimens were examined by microscopic computerized tomography (micro-CT). Subsequently, they underwent decalcification and were stained for histologic analysis.

RESULTS

There was no significant difference between groups at 6 weeks after operation. In the micro-CT results, however, tissue mineral content in the experimental group at 12 weeks after operation was 132.09 +/- 4.41 and that in the control group was 126.42 +/- 6.62 (P = .011). Tissue mineral density in the experimental group was 2,088.88 +/- 648.34, and that in the control group was 2,029.72 +/- 668.22 (P = .013). The results of the histomorphometric analysis were in accordance with the micro-CT results. The total new bone was 49.86 +/- 7.49% in the control group at 12 weeks after the operation and 59.83 +/- 10.92% in the experimental group (P = .021).

CONCLUSION

A combined application of Choukroun PRF with acid-digested silk fibroin showed more rapid bone healing than unfilled control.

Effect of Tisseel on bone healing with particulate dentin and plaster of Paris mixture

OBJECTIVES

The purpose of this study was to evaluate the effect of Tisseel on the early healing of bone defects in the skulls of rats.

STUDY DESIGN

Forty-eight rats were randomly assigned to 4 groups, and each group was further divided into 3 subgroups which were examined at 4 and 8 weeks after the defects were filled. The 4 different groups were animals containing: no graft (group 1); particulate dentin and plaster of Paris mixture graft (group 2); Tisseel and particulate dentin and plaster of Paris mixture graft (group 3); and Tisseel graft (group 4). After killing the animals at 4 and 8 weeks after surgery, all implant blocks were prepared for histologic sections and histomorphometric analysis.

RESULTS

The overall new bone formation was significantly different between the 4-week samples and the 8-week samples. Significant differences between groups 1 and 2, groups 1 and 3, groups 1 and 4, groups 2 and 4, and groups 3 and 4 were observed at 4 weeks after surgery. At 8 weeks after surgery, significant differences between groups 1 and 2, groups 1 and 3, groups 1 and 4, and groups 2 and 4 were observed. As expected, effective bone formation was observed when the defects were filled with either particulate dentin, Tisseel, or particulate dentin-Tisseel combination. It was also observed from this study that particulate dentin is especially effective, followed by the particulate dentin-Tisseel combination and Tisseel.

CONCLUSION

It was concluded that the use of Tisseel may be an alternative therapy for regenerating bone in defects when used in combination with particulate dentin.

The biology of platelet-rich plasma and its application in oral surgery: literature review

Platelet-rich plasma (PRP) is a new approach in tissue regeneration and a developing area for clinicians and researchers. It is used in various surgical fields, including oral and maxillofacial surgery. PRP is prepared from the patient's own blood and contains growth factors that influence wound healing. Of these growth factors, platelet-derived growth factor, transforming growth factor, insulin-like growth factor, and epidermal growth factor play a pivotal role in tissue repair mechanisms. Although the growth factors and mechanisms involved are still poorly understood, the easy application of PRP in the clinic and its possible beneficial outcome, including reduction of bleeding, rapid soft tissue healing, and bone regeneration, hold promise for new treatment approaches. However, animal studies and human trials demonstrate conflicting results regarding the application of PRP. Therefore the aim of this literature review is to evaluate the scientific evidence regarding the use of PRP in dentistry, to describe the different bioactive substances included in PRP and their participation in the healing process, to elucidate the different techniques and available technology for PRP preparation, to review animal and human studies, to clarify risks, and to provide guidance for future research.