|Year : 2011 | Volume
| Issue : 2 | Page : 42-50
Five years of clinical and radiographical evaluation of implant survival and dimensional stability of maxillary sinus augmentation procedures performed with platelet-rich plasma
Carlo Maiorana1, Paolo Brivio1, Mario Beretta1, Giovanni Battista Grossi1, Marco Cicciù2
1 Department of Oral Surgery and Implantology, School of Dentistry, University of Milan, Milan, Italy
2 Department of Odontostomatology, University of Messina, Messina, Italy
|Date of Web Publication||30-Dec-2011|
Department of Odontostomatoly, School of Dentistry, Messina University, Via Consolare Valeria 98100, Messina
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Purpose: Aim of the present study was to present the results of a retrospective analysis of maxillary sinus augmentation procedures performed with platelet-rich plasma (PRP) with a mean follow-up of about 5 years. The analysis was focused on implant survival rates and on the dimensional stability of the subantral cavity filling.
Materials and Methods: Between 2000 and 2006, 28 patients were recruited for a maxillary sinus augmentation procedure performed with PRP. Two patients did not answer to the calling for the examination at distance, so they were excluded from the sample. The study involved 26 patients, for a total amount of 33 sinus augmentations, with an average follow-up of 65 months. In 26 procedures the grafting material used was a mixture of autologous bone taken from the oral cavity, deproteinized bovine bone Bio-Oss® in a relationship of 1:3 and PRP, while in seven cases, the combination of Bio-Oss and PRP. The dimensional stability of grafting material was investigated through X-ray measurements carried out during X-ray postexaminations.
Results: After a mean follow-up time of about 5 years, the implant survival rate registered was 95.9%, while the radiographical variables used to assess the dimensional stability of grafts, showed a mean decrease respectively of 9.38% and 14.61%.
Discussion: Very good long-term results were achieved using autologous bone+Bio-Oss+PRP and Bio-Oss+PRP as filling materials in the maxillary sinus augmentation. Dimensional stability of cavity filling seems to represent a very important factor for implant procedures success. It is difficult to estimate the influence of PRP on a long-term basis.
Conclusion: The implant survival rate obtained in this study was similar to the expected rate on the areas not subject to bone graft. The method applied showed to be reliable for bone regeneration in subantral cavities, showing a very good dimensional stability and a slight reabsorption over the years.
Keywords: Dental implants, platelet-rich plasma, sinus lift
|How to cite this article:|
Maiorana C, Brivio P, Beretta M, Grossi GB, Cicciù M. Five years of clinical and radiographical evaluation of implant survival and dimensional stability of maxillary sinus augmentation procedures performed with platelet-rich plasma. J Dent Implant 2011;1:42-50
|How to cite this URL:|
Maiorana C, Brivio P, Beretta M, Grossi GB, Cicciù M. Five years of clinical and radiographical evaluation of implant survival and dimensional stability of maxillary sinus augmentation procedures performed with platelet-rich plasma. J Dent Implant [serial online] 2011 [cited 2023 Jun 8];1:42-50. Available from: https://www.jdionline.org/text.asp?2011/1/2/42/91279
| Introduction|| |
The treatment of maxillary edentulous jaws with osteointegrated implants is often complex for the frequent coronally pneumatization of the maxillary sinus and for the remaining low bone density. The bone resorption, consequent to the loss of the dental elements, determines atrophy in height, and in thickness, by reducing the amount of available bone to the implant placement. In the 1970s Tatum  and then Boyne and James,  developed the surgical technique of the maxillary sinus augmentation. The proposed approach represents the most reliable procedure for the bone reconstruction at the maxillary sinus. Many different filling subantral materials have been used over the years. Autologous bone represented for years, the gold standard in bone grafting procedures for his osteoinductive, osteogenic and osteoconductive abilities. On the other hand, the morbidity deriving from the need of a double surgical site has prompted the researchers to develop alternative procedures using alloplastic, eterologous materials and growth factors to support the bone regeneration. ,,,,,,,,,,,
Platelet-rich plasma (PRP) constitutes an autologous source of growth factors involved in the osteogenic and angiogenetic procedures. ,,,, Its use in sinus augmentation has been often supported even if today's debate about its effective usefulness is still open in the scientific community. ,,,,,,,,,,,,,,,,,
The aim of this article was to show, through a retrospective analysis of the cases carried out in our structure, the results of using PRP as filling comaterial in maxillary sinus augmentation procedures, in association with heterologous material, with particular focus on the implant survival and the dimensional stability of bone grafts in the course of time.
| Materials and Methods|| |
Between 2000 and 2006, in the "Implantology Department", 28 patients were subjected to maxillary sinus augmentation procedure, adding PRP on the subantral cavity filling. Among them, two patients were excluded from the sample as they did not attend the medical check-up after at distance.
The study involved 26 patients (18 female and 8 male) with a mean age of 54 ± 9.1 years in between a range of 37-70-years old. One patient was completely edentulous, and the other 25 were partially edentulous in the posterior maxilla [Table 1].
Thirty-three maxillary sinus augmentation procedures were totally performed; one with a one-stage approach and 32 with a two-stage approach plus implant filling 6 months after the grafting procedure.
According to the PRP preparation protocol, each patient was subjected to the drawing of a whole blood unit (450 cm 3 ) the day before the surgical procedure. The whole unit underwent to two consecutive centrifugations in a gradient of density cells separator. The first centrifugation was performed at 2500 rpm for 8 minutes with a 281-mm centrifugal ray, permitting the separation of blood into its three main components: Red blood cells, PRP and platelet-poor plasma (PPP).
PRP, immediately separated from the other plasmatic components, was subject to a second centrifugation at 3950 rpm for 7.5 minutes with a 281-mm centrifugal ray, permitting a further concentration of platelets in a lower quantity of plasma.
The bag, containing a PRP quantity ranging from 30 to 40 cm 3 , was kept in continuous motion 20°C, until the time of surgery, in order to prevent premature platelet aggregation.
At surgery time, according to the procedure, PRP was transformed in a manageable gel, by platelet aggregation obtained by adding 1 cm 3 of a calcium chloride solution (10%) and two vials of batroxobin (Botropase® Ravizza Farmaceutici Spa Muggiò) as a coagulant factor.
For the sinus augmentation, Tatum's surgical lateral procedure was used. Briefly, once a midcrestal incision was made to allow for the lifting of a superior buccal full thickness flap, exposing the atrophic alveolar ridge, an osteotomy, delimiting the bone window, was performed to allow for access to the sinus cavity, the mobilization of the Schneiderian membrane, creating a virtual cavity fit, to receive the grafting material. During the surgical procedure the PRP was transformed in a manageable gel according to the described process.
For 26 sinus augmentation procedures the grafting material was composed of a mixture of autologous bone taken from tuber and neighbouring areas by the use of Safescraper (Meta, Reggio Emilia, Italy), and deproteinized bovine bone bio-OSS® (Geistlich, Wolhsen, Switzerland), in a relationship of 1:3 and PRP; for the other seven procedures, only the combination of bio-OSS and PRP has been used.
During the study, 28 Branemark implants were inserted (Nobel Biocare, Goteborg, Sweden), 25 Frialit-2® implants (Friatec AB, Mannheim, Germany), 7 Camlog implants (Altatech), 5 T.B.R. implants (Benax, Ancona, Italy), 4 3i® implants (Implant Innovations, Inc. USA) e 2 Astra implants (Astratech, Goteborg, Sweden) for a total amount of 73 implants inserted in grafted sites.
Six months after the grafting procedure implants were inserted. Twenty-five patients received a fixed prosthetic rehabilitation and 1 patient a removable prosthesis with a bar anchored to the implants [Table 2].
|Table 2: Number of sinus augmentations and implants according to the grafting material|
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For the radiographical evaluations, panoramic X-rays were taken immediately after augmentation and after an average period of observation of 65.23, 97 months, with a minimum of 31 and up to 100 months.
X-rays were carried out all with the same machine and the same radiographical film: Siemens Orthophos (Germany) e Kodak Dental film.
X-rays poorly observable or affected by head positioning errors were not taken into consideration for the measurements of the changes of grafting material during time.
X-rays taken into consideration were scanned and became digital printings to be evaluated with a digital program. In order to obtain correct measurements, software Acrobat Reader Professional 7.0 were used. This software, on the basis of well-known measurements such as the length of the implants in the panoramic images, led to obtain a scale to compare measurements studied.
Thirty-six X-rays as a total have been taken into consideration on 18 patients. According to Hatano et al.,  four variables were measured and recorded by the measurement instrument of the software. In order to evaluate changes in each implant's sinus-graft, following variables were considered:
- Implant length (IL) defined as the distance between the apex and the head of the fixture
- Bone Level (BL) defined as the distance between the highest level of the grafted sinus floor on each implant and the implant's head itself.
In order to evaluate changes in sinus-graft height compared to the original sinus floor following variables were considered:
- Original Sinus Height (OSH), defined as the distance between the bone intraoral margin and the lowest point of the original sinus floor
- Grafted Sinus Height (GSH), defined as the distance between the bone intraoral margin and the new grafted sinus floor located over the lower point of the original sinus floor (OSH) [Figure 1].
|Figure 1: IL - Implant length; BL - Bone length; OSH - Original sinus height; GSH - Grafted sinus height|
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In order to state the relationship between the sinus graft height and each implant, the BL ratio as BL/IL was introduced. A value exceeding 1 indicates that the grafted sinus floor is above the implant apex; a value less than 1 means that the grafted sinus floor is below the implant apex and the implant apex is not completely covered by the sinus floor.
Similarly, GSH/OSH ratio was introduced the. A value exceeding 1 indicates that the grafted sinus floor is above the original sinus floor. This ratio has been used to compare the sinus graft height on the not-implants-supported areas.
Implants were divided into three groups based on the height of the grafted sinus floor relative to the implant apex:
- Group I, in which the grafted sinus floor was above the implant apex;
- Group II, in which the implant apex was level with the grafted sinus floor; and
- Group III, in which the grafted sinus floor was below the implant apex
| Results|| |
Implant survival rate
At the time of the first check-up, corresponding to the implant uncover, 3 of 73 implants were classified as not integrated, thus removed and showing a premature failure rate of 4,1%. Particularly, two implants were lost after being lifted with Bio-Oss and PRP, one with mixture of autologous Bio-Oss and PRP. After those failures, during the whole observation period, (65.18 ± 23.97 months minimum 31, up to 100 months), no failures were recorded, bringing to a cumulative survival rate of 95.9%. Following Tables show in detail the cumulative survival rate in relation to the observing period and to the graft type [Table 3] and [Table 4].
Radiographic evaluation of graft height changes
In order to perform a clinical long-term evaluation of the dimensional stability of the sinus grafts, 36 panoramic X-ray images, of 18 patients and showing 256 measurements, were used. The average value of the ratio BL/IL, immediately measured after the placements of implants, was 1.30 ± 0.25. The same ratio, after an average observation period of 65.18 ± 23.97 months, was 1.17 ± 0.21 with an average decrease of 10%. The average ratio value exceeding 1 indicates that the implant apex remains covered by the grafted sinus floor, even after many months, for most of the implants [Table 5].
The average value of the ratio GSH/OSH decreased of 15%, from 3.31 ± 1.55 at first measurement, to 2.81 ± 1.14 at the time of the control. The average value of the ratio exceeding 1, indicates that the grafted sinus floor is above the original floor, even after 5 years [Figure 2], [Figure 3], [Figure 4] and [Figure 5].
|Figure 2: BL changes between first and second measuring in mm (a) and in percentage (b)|
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|Figure 3: GSH changes between first and second measuring in mm (a) and in percentage (b)|
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|Figure 4: BL changes in mm (a) and in percentage; (b) according to Autologous+Bio-Oss+PRP group|
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|Figure 5: GSH changes in mm (a) and in percentage; (b) according to Autologous+Bio-Oss+PRP group|
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Taking into consideration BL and GSH values, at the time of the clinical exam, they decreased respectively of 9.38 ± 0.08% and 14.61 ± 0.10%.
Following graphics show the changes of measurements on the OPTs, in general and related to the specific implant [Figure 6], [Figure 7] and [Figure 8].
|Figure 6: BL changes in mm (a) and in percentage; (b) according to Bio-Oss+PRP group|
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|Figure 7: GSH changes in mm (a) and in percentage; (b) according to Bio-Oss+PRP group|
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|Figure 8: Mean BL and GSH changes according to Autologous+Bio-Oss+PRP group and to Bio-Oss+PRP group|
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| Discussion|| |
The objectives of this retrospective analysis, performed on the clinical experience of "Implantology Department", were the evaluation of implant survival and dimensional changes of subantral grafting material during time.
Data were obtained from archives analyses and both radiographical and clinical exams of the patients, during the period 2000 and 2008.
In literature, many different clinical implant survival rates have been reported, varying between 70 and 100%. Results' variation depends on different factors: Different follow-up, inclusion criteria, used materials, prosthetic and surgical treatments. All those factors complicate the comparison of different studies.
The implant-prosthetic rehabilitating treatment of the sample, led to obtain a implant survival rate of 95.9%, with an average examination period of 5 years. This survival rate is very similar to the recently evaluated cases in a retrospective investigation on 10 years of clinical activity of Implantology Department. Bone regeneration stability and the reliability on the maintenance of the osteointegration after many years are confirmed by the absence of implants failures after a period of time.
The different implant survival rate between the autologous+Bio-Oss+PRP group and the Bio-Oss+PRP group can not be considered statistically valid because of the not homogeneous number of patients included in the two groups.
Dimensional stability of cavity filling represents a very important factor for success of implant procedures. Many different clinical and observational studies showed that using different materials, such as autologous bone, deproteinized bovine bone and others, could be clinically effective and predictable. ,,,,,,,
Autologous bone has been considered the gold standard for years, but its use could be limited by the donator's morbidity, by its reduced availability and by its variable resorption.
Different authors proposed the use of eterologous materials such as deproteinized bovine bone, which low resorbing characteristic could maintain the implant's volume during the years. ,,
The data, collected by panoramic image's measurements, showed an average reduction of the graft height of 9.38 ± 0.08% in the areas supporting implants and of 14.61 ± 0.10% in the interimplant areas. This difference may suggest a stabilizing effect the graft height maintenance by the loads applied to implants. Similarly, the preservation of graft height and so its dimensional stability may be associated with an absence of implant failures after a period of time.
In the sample, a good relation between the graft and the implant during the years was confirmed by measurements taken for each implant inserted in the reconstructed bone.
As a conclusion of this retrospective analysis, it is possible to sustain that very good long-term results were achieved both using the mixture of autologous bone+Bio-Oss+PRP and of Bio-Oss+PRP, as grafting materials in the sinus augmentation procedures. Dimensional stability of cavity filling seems to represent a very important factor for implant success.
It is difficult to measure the influence of PRP over the long-term results. The rational principle which constitutes the basis of using PRP as a stimulus for bone regeneration consists in the possibility of concentrating the growth factors included in platelets and addressing them in regenerating sites through an ideal carrier, which are the patient's platelets.
During the bone regeneration process, the growth factors play an important role both at the beginning and in maintaining the differentiation and proliferation of osteoprogenetic cells and osteoblasts, which lead to the regeneration of the new bone.
In the early phases, TGF-b and PDGF released by platelets admitted to form the clot, promote the maturation of the osteoprogenitor cells towards the osteoblastic line in combination with the growth factors released by the traumatized bone tissue.
The whole combination of these tissue-repairing promotion activities stimulates specifically the expression and the synthesis of other regulating factors of macrophages and osteoblasts occurred in the regenerating site.  Among them BMPs synthesized by endosteal osteoblasts, early emerge thus contributing to the osteoblastic differentiation of totipotency mesenchymal cells.
Once the regenerating process has started, it can automatically maintain a high proliferative and metabolic level, through the synthesis of the same growth factors by osteoblasts implicated in the process, also sustained by capillary angiogenesis promoted by the PDGF. ,,
Because of its nature, the effect of PRP blows over in the first 2 weeks after the grafting procedure; while in the long period the osteoconductive characteristics of the graft prevail. It is possible that the fibrin texture resulting from the polymerization of fibrinogen contained in the PRP clot provides to the bio-OSS graft a further framework or "binary guide" for the migration of osteoblasts in contact with the surface of the granules of bio-material, and that growth factors platelet enhance the potential regeneration, even in a little active grafting site like the subantral cavity of the maxillary sinus.
According to the literature, many different benefits have been proposed to use PRP for sinus augmentation:
- Higher quantity and quality of the regenerated bone; ,,,
- Reduction of the osteointegration time; 
- Improvement of the healing of soft tissues; 
- No risk of illness transmission; 
On the other hand there have been raised limitations on its use:
- Need of vital cells to became a bone regeneration stimulus; 
- Limited time effect; ,
- Low number of platelets determines limited time effects; 
- Different ways of preparation could invalidate platelets' physiology modifying the ability of producing growth factors;
A recent literature review , showed how since 2000 many different studies upon animals and humans have been published regarding PRP as a filling material in sinus augmentation, but many of them are incomplete from a scientific point of view and they often bring to positive solutions without being supported by a right design of the study itself.
In conclusion, only a few scientifically proven data exist on the benefit of adding PRP to the usual procedures of sinus augmentation.
Theoretically, PRP has many positive effects, such as being an autologous source of growth factors, which is able to cure wounds by itself, nevertheless its use cannot be supported on the basis of the literature and other randomized and controlled studies have to be performed before giving a unique opinion on its routine use.
| Conclusions|| |
Clinical survival rate of implant obtained in this retrospective study confirms the validity of the subantral filling procedure. The use of eterologous bone as substitutes led to bone regeneration, reliable from an implant survival and dimensional stability point of view, showing a very low radiographical resorption. We cannot provide a final evaluation judgment on the PRP filling long-term results, other prospectical studies have to be performed in order to evaluate PRP routine-use in sinus augmentation for pre-implant purposes.
| References|| |
|1.||Tatum H Jr. Maxillary and sinus implant reconstructions. Dent Clin North Am 1986;30:207-29. |
|2.||Boyne PJ, James RA. Grafting of the maxillary sinus floor with autogenous marrowand bone. J Oral Surg 1980;38:613-6. |
|3.||Korlof B, Nylin B, Ritz KA. Bone grafting of skull defects: A report of 55 cases. Plast Reconstr Surg 1973;52:378-83. |
|4.||Johansson B, Grepe A, Wannfors K. CT-scan in assessing volumes of bone grafts to the heavily resorbed maxilla. J Craniomaxillofac Surg 1998;26:85. |
|5.||Zins JE, Whitaker LA. Membranous versus encondral bone: Implication for craniofacial reconstruction. Plast Reconstr Surg 1983;72:778. |
|6.||Jensen J, Sindet-Pedersen S. Autogenous mandibular bone grafts and osseointegrated implants for reconstruction of the severely resorbed maxilla: A preliminary report. J Oral Maxillofac Surg 1991;49:1277. |
|7.||Tulasne JF. Sinus grafting with calvarial bone. In: Jensen OT (editor). The Sinus Bone Graft. Chicago, IL: Quintessence; 1999. p. 107-16. |
|8.||Beirne OR. Comparison of complications after bone removal from the lateral and medial plates of the ileum for mandibular augmentation. Int J Oral Surg 1986;15:269. |
|9.||Nystrom E, Kahnberg KE, Gunne J. Bone grafts and Brånemark implants in the treatment of the severely resorbed maxilla: A 2-year longitudinal study. Int J Oral Maxillofac Implants 1993;8:45-53. |
|10.||Nkenke E, Schultze-Mosgau S, Radespiel-Troger M, Kloss F, Neukam FW. Morbidity of harvesting of chin grafts: A prospectivestudy. Clin Oral Implants Res 2001;12:495-502. |
|11.||Smiler DG, Holmes RE. Sinus liftprocedure using porous hydroxyapatite: A preliminary clinical report. J Oral Implantol 1987;13:239-53. |
|12.||Moy PK, Lundgren S, Holmes RE. Maxillary sinus augmentation: Histomorphometricanalysis of graft materials for maxillary sinus floor augmentation. J Oral Maxillofac Surg 1993;51:857-62. |
|13.||Wetzel AC, Stich H, Caffesse RG. Bone apposition onto oral implants in the sinus area filled with different grafting materials. A histological study in beagle dogs. Clin Oral Implants Res 1995;6:155-63. |
|14.||Tadjoedin ES, de Lange GL, Holzmann PJ, Kulper L, Burger EH. Histological observations on biopsies harvested following sinus floor elevation using a bioactive glass material of narrow size range. Clin Oral Implants Res 2000;11:334-44. |
|15.||Anitua E. Plasma rich in growth factors: Preliminary results ofuse in the preparation of future sites for implants. Int J Oral Maxillofac Implants 1999;14:529-35. |
|16.||Anitua E. The use of plasma-rich growth factors (PRGF) in oralsurgery. Pract Proced Aesthet Dent 2001;13:487-93. |
|17.||Marx RE, Carlson ER, Eichstaedt RM, Schimmele SR, Strauss JE, Georgeff KR. Platelet-rich plasma: Growth factor enhancement for bone grafts. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;85:638-46. |
|18.||Marx RE. Clinical application of bone biology to mandibular and maxillary reconstructions. Clin Plast Surg 1994;21:377-92. |
|19.||Marx R, Lynch SE, Genco RJ, Marx RE. Platelet-rich plasma: A source of multiple autologous factors for bone grafts. In: Lynch S, Genco R, Marx R, Editors. Tissue engineering. Chicago, Berlin, London, Tokyo, Paris, Barcelona, San Paulo, Moscow, Prague and Warsaw: Quintessence Publishing Co., Inc.;1999. p. 71-82. |
|20.||Klongnoi B, Rupprecht S, Kessler P, Thorwarth M, Wiltfang J, Schlegel KA. Influence of platelet-rich plasma on a bioglass and autogenous bone in sinus augmentation. An explorative study. Clin Oral Implants Res 2006;17:312-20. |
|21.||Belli E, Longo B, Balestra FM. Autogenous platelet-rich plasma in combination with bovine-derived hydroxyapatite xenograft for treatment of a cystic lesion of the jaw. J Craniofac Surg 2005;16:978-80. |
|22.||Camargo PM, Lekovic V, Weinlaender M, Vasilic N, Madzarevic M, Kenney EB. Platelet-rich plasma and bovine porous bone mineral combined with guided tissue regeneration in the treatment of intrabony defects in humans. J Periodontal Res 2002;37:300-6. |
|23.||Furst G, Gruber R, Tangl S, Zechner W, Haas R, Mailath G, et al. Sinus grafting with autogenous platelet-rich plasma and bovine hydroxyapatite. A histomorphometric study in minipigs.Clin Oral Implants Res 2003;14:500-8. |
|24.||Hauschild G, Merten HA, Bader A, Uhr G, Deivick A, MeyeLindenberg A, et al. Bioartificial bone grafting: Tarsal joint fusion in a dog using a bioartificial composite bone graft consisting of beta-tricalciumphosphate and platelet rich plasma-a case report. Vet Comp Orthop Traumatol 2005;18:52-4. |
|25.||Hofman S, Sidqui M, Abensur D, Valentini P, Missika P. Effects of Laddec on the formation of calcified bone matrix in rat calvariae cells culture. Biomaterials 1999;20:1155-66. |
|26.||Hokugo A, Ozeki M, Kawakami O, Sugimoto K, Mushimoto K, Morita S, et al. Augmented bone regeneration activity of platelet-rich plasma by biodegradable gelatin hydrogel. Tissue Eng 2005;11:1224-33. |
|27.||Ip TH. Using platelet-rich plasma to enhance a composite graft in the maxillary sinus. Dent Implantol Update 2003;14:9-14. |
|28.||Jensen SS, Broggini N, Weibrich G, Hjorting-Hansen E, Schenk R, Buser D. Bone regeneration in standardized bone defects with autografts or bone substitutes in combination with platelet concentrate: A histologic and histomorphometric study in the mandibles of minipigs. Int J Oral Maxillofac Implants 2005;20:703-12. |
|29.||Klongnoi B, Rupprecht S, Kessler P, Zimmermann R, Thorwarth M, Pongsiri S, et al. Lack of beneficial effects of platelet rich plasma on sinus augmentation using a fluorohydroxyapatite or autogenous bone: An explorative study. J Clin Periodontol 2006;33:500-9. |
|30.||Lioubavina-Hack N, Carmagnola D, Lynch SE, Karring T. Effect of Bio-Oss with or without platelet-derived growth factor on bone formation by "guided tissue regeneration": A pilot study in rats. J Clin Periodontol 2005;32:1254-60. |
|31.||Maiorana C, Sommariva L, Brivio P, Sigurta D, Santoro F. Maxillary sinus augmentation with anorganic bovine bone (Bio-Oss) and autologous platelet-rich plasma: Preliminary clinicaland histologic evaluations. Int J Periodontics Restorative Dent 2003;23:227-35. |
|32.||Sarkar MR, Augat P, Shefelbine SJ, Schorlemmer S, Huber-Lang M, Claes L, et al. Bone formation in a long bone defect model using a platelet-rich plasma-loaded collagen scaffold. Biomaterials 2006;27:1817-23. |
|33.||Schlegel KA, Donath K, Rupprecht S, Falk S, Zimmermann R, Felszeghy E, et al. De novo bone formation using bovine collagen and platelet-rich plasma. Biomaterials 2004;25:5387-93. |
|34.||Thorwarth M, Rupprecht S, Falk S, Felszeghy E, Wiltfang J, Schlegel KA. Expression of bone matrix proteins during de novo bone formation using a bovine collagen and platelet-rich plasma (prp) - an immunohistochemical analysis. Biomaterials 2005;26:2575-84. |
|35.||Thorwarth M, Wehrhan F, Schultze-Mosgau S, Wiltfang J, Schlegel KA. PRP modulates expression of bone matrix proteins in vivo without long-term effects on bone formation. Bone 2006;38:30-40. |
|36.||Wiltfang J, Kloss FR, Kessler P, Nkenke E, Schultze-Mosgau S, Zimmermann R, et al. Effects of platelet-rich plasma on bone healing in combination with autogenous bone and bone substitutes in critical-size defects. An animal experiment. Clin Oral Implants Res 2004;15:187-93. |
|37.||Wiltfang J, Schlegel KA, Schultze-Mosgau S, Nkenke E, Zimmermann R, Kessler P. Sinus floor augmentation with betatricalciumphosphate beta-TCP): Does platelet-rich plasma promote its osseous integration and degradation? Clin Oral Implants Res 2003;14:213-8. |
|38.||Hatano N, Shimizu Y, Ooya K. A clinical long-term radiographicevaluation of graft height changes aftermaxillary sinus floor augmentationwith a 2: 1 autogenous bone/xenograft mixture and simultaneous placement of dental implants. Clin Oral Impl Res 2004;15:339-45. |
|39.||Smiler DG, Holms RE. Sinus lift procedure using porous hydroxyapatite: A preliminary clinical report. J Oral Implantol 1987;13:239-53. |
|40.||Hürzeler MB, Quiñones CR, Kirsch A, Gloker C, Schüpbach P, Strub JR, et al. Maxillary sinus augmentation using different grafting materials and dental implants in monkeys. Part I. Evaluation of anorganic bovine derived bone matrix. Clin Oral Implant Res 1997;8:476-86. |
|41.||Block MS, Kent JN, Kallukaran FU, Thunthy K, Weinberg R. Bone manteinance 5 to 10 years after sinus grafting. J Oral Maxillofac Implants 1998;56:706-14. |
|42.||Haas R, Donath K, Fodiger M, Watzek G. Bovine hydroyapatite for maxillary sinus grafting: Comparative histomorphometric findings in sheep. Clin Oral Implant Res 1998;9:107-116. |
|43.||Lorenzoni M, Pertl C, Wegscheider W, Keil C, Penkner K, Polansky R, et al. Retrospective analysis of Frialit-2 implants in the augmented sinus. Int J Periodontics Restorative Dent 2000;20:255-67. |
|44.||Valentini P, Abensur D, Wenz B, Peets M, Schenk R. Sinus grafting with porous bone mineral (Bio-Oss) for implant placement: A 5 years study on 15 patients. Int J Periodontics Restorative Dent 2000;20:245-253. |
|45.||Hallman M, Hedin M, Sennerby L, Lundgren S. A prospective 1 year clinical and radiographic study of implants placed after maxillay sinus floor augmentation with bovine hydroxyapatite and autogenous bone. J Oral Maxillofac Surg 2002;60:277-284 |
|46.||Norton MR, Odell EW, Thompson ID, Cook RJ, Efficacy of bovine bone mineral for alveolar augmentation: A human histologic study. Clin Oral Implant Res 2003;14:775-83. |
|47.||Nystrom E, Ahlquis J, Gunne J, Kanhberg KE. 10-year follow-up of onlay bone grafts and implants in severely resorbed maxillae. Int J Oral Maxillofac Surg 2004;33:258-62. |
|48.||Maiorana C, Beretta M, Salina S, Santoro F. Reduction of autogenous bone graft resorption by means of Bio-oss coverage: A prospective study. Int J Periodontics Restorative Dent 2005;25:19-25. |
|49.||Schegel KA, Fichtner G, Schultze-Mosgau S, Wiltfang J. Histologic findings in sinus augmentation with autogenous bone chips versus a bovine bone substitute. Int J Oral Maxillofac Implants 2003;18:53-8. |
|50.||Hallamn M, Hedin M, Sennerby L, Lundgren S. A prospective 1-year clinical and radiographic study of implants placed after maxillary sinus flooe augmentation with bovine hydroyapatite and autogenous bone. J Oral Maxillofac Surg 2002;60:277-84. |
|51.||Sandberg MM, Aro HT, Vuorio EI. Gene expression during bon repair. Clin Orthop Relat Res 1993:289:292-312. |
|52.||Canalis E, McCarthy TL, Centrella M. Effects of PDGF on bone formation in vitro. J Cell Physiol 1989;270:530-37. |
|53.||Bolander ME. Regulation of fracture repair by growth factors. Proc Soc Exp Biol Med 1992;200:165-70. |
|54.||Lind M. Growth factor stimulation of bone healing. Effects on osteoblasts, osteomies, and implants fixation. Acta Orthop Scand Suppl 1998;283:2-37. |
|55.||Sammartino G, Tia M, Marenzi G, di Lauro AE, D'Agostino E, Claudio PP. Use of autologous platelet-rich plasma (PRP) in periodontal defect treatmentafter extraction of impacted mandibularthird molars. J Oral Maxillofac Surg 2005;63:766-70. |
|56.||Nash TJ, Howlett CR, Martin C, Steele J, Johnson KA, Hicklin DJ. Effect of platelet-derived growth factoron tibial osteotomies in rabbits. Bone 1994;15:203-208. |
|57.||Mazor Z, Peleg M, Garg AK, Luboshitz J. Platelet-rich plasma for bone graft enhancement in sinus floor augmentation with simultaneous implant placement: Patient series study. Implant Dent. 2004;13:65-72. |
|58.||Marx RE. Platelet-rich plasma: Evidence to support its use. J Oral Maxillofac Surg 2004;62:489-96. |
|59.||Gruber R, Varga F, Fischer MB, Watzek G. Platelets stimulate proliferation of bone cells: Involvement of platelet-derived growth factor, microparticles and membranes. Clin Oral Implants Res 2002;13:529-35. |
|60.||Steigmann M, Garg AK. A comparative study of bilateral sinus lifts performed with platelet-rich plasma alone versus alloplastic graft material reconstituted with blood. Implant Dent 2005;14:261-6. |
|61.||Lakshmi B, Hom-Lay W. The role of platelet-rich plasma in sinusaugmentation: A critical review. Implant Dent 2006;15:160-70. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]