Histologic and Radiographic Comparison of Bone Scraper and Trephine Bur for Autologous Bone Harvesting in Maxillary Sinus Augmentation Paolo Maridati, DDS, PhD1/Claudia Dellavia, DDS, PhD2/Gaia Pellegrini, DDS, PhD3/ Elena Canciani, MSc3/Andrea Maragno, DDS4/Carlo Maiorana, MD, DDS5 Purpose: The aims of this study were to investigate the best two of five common methods of collecting autologous bone (preliminary study [PS]) and to test clinically the effects of autografts harvested using a trephine bur or bone scraper for sinus augmentation surgery (main study [MS]). Materials and Methods: In the PS, five autograft samples from five patients (n = 25) were harvested with a bone scraper, round bur, piezoelectric device, implant bur, and trephine bur and were processed for histomorphometric analysis. In the MS, sinus augmentation was performed on 20 patients using bovine-derived bone substitute and autograft collected with a trephine bur (group A, n = 10) or collected with a bone scraper (group B, n = 10). Narrow implants were also placed. At 6 months, changes in graft volume were evaluated with cone beam computed tomography. The amounts of regenerated bone, residual graft, and osseointegration of the implants were assessed histologically. Results: In the PS, the trephine bur and bone scraper harvested bone chips that were medium to large and more vital than those obtained with the other tools. In the MS, no significant differences were seen between groups in terms of the amount of residual biomaterial, regenerated bone, change in graft volume, and osseointegration. Conclusion: Biologic differences between these two bone particulates may not influence regeneration and implant osseointegration in sinus augmentation when mixed with xenograft bone. Int J Oral Maxillofac Implants 2015;30:1128–1136. doi: 10.11607/jomi.3810 Key words: autograft, bone regeneration, cone beam computed tomography, sinus augmentation, tissue harvesting, xenograft

J

aw atrophy subsequent to periodontal disease, tooth loss, or maxillofacial trauma frequently necessitates the reconstruction of the alveolar process

1Freelance

Dentist, Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Italy; Dental Clinic, Policlinic Hospital, Ca’ Granda Foundation, Milano, Italy. 2Professor, Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Italy. 3Research Fellow, Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Italy. 4Freelance Dentist, Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Italy. 5Professor, Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Italy; Dental Clinic, Policlinic Hospital, Ca’ Granda Foundation, Milano, Italy. The first two authors contributed equally to this study. Correspondence to: Dr Gaia Pellegrini, Via Mangiagalli 31, 20133 Milano, Italy. Fax: +39-02-50315387. Email: [email protected] ©2015 by Quintessence Publishing Co Inc.

before implant placement. Reconstructive techniques in oral surgery (vertical ridge augmentation, sinus augmentation) use osteoconductive materials as a scaffold to guide bone regeneration.1,2 Because of its osteogenic, osteoconductive, and osteoinductive properties, autogenous bone is considered the “gold standard” among graft materials for oral reconstructive procedures,1–3 and several preclinical and clinical studies evaluating new medical formulations for bone regeneration used autogenous bone as a reference material.4,5 However, because of the risk of donor site morbidity and high volumetric contraction, in regenerative procedures autogenous bone is frequently used in combination with stable and easily available— but nonvital—xenograft material.6,7 In clinical practice, autogenous bone chips can be obtained with traps that collect bone debris during implant surgery, with piezoelectric terminals, with bone scrapers, or by particulating bone blocks. Studies that compared the shape, size, and cellular characteristics of bone chips harvested with different methods agree that microscopic morphology, dimensions, and vitality vary with the device used for tissue harvesting and may

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influence the osteogenic potential of the graft.3,8–10 However, these studies compared only a few methods,8–11 used iliac crestal bone, which is embryologically different from mandibular bone,3 harvested tissue samples from animals,9 evaluated only one sample per method,10 or performed only in vitro analysis without adjunctive clinical tests of data.3–9 Therefore, the present study had two aims. The preliminary study sought to investigate in humans the two best of five common harvesting procedures for collecting autologous bone in terms of chip dimensions and cell viability. The main study sought to test clinically the effects of autografts harvested using the selected procedures (trephine bur, bone scraper) in sinus augmentation surgery in terms of the quality of the regenerated bone at 6 months after surgery (histomorphometry), osseointegration of small-diameter implants (histomorphometry), and graft contraction (evaluated with cone beam computed tomography [CBCT]).

MATERIALS AND METHODS

the alveolar process of the mandible, posterior to the first and second molars, over the external oblique line. In each patient, samples were harvested by means of each of these devices: • Bone scraper (Safescraper, Meta). • Stainless steel 1.8-mm-diameter round bur (Astra Tech) on a low-speed handpiece (1,000 rpm) under continuous irrigation with sterile physiologic solution. • Stainless steel 2-mm-diameter spiral bur covered with titanium nitride (Astra Tech) on a low-speed handpiece (800 rpm) under continuous irrigation with sterile physiologic solution. • Piezoelectric device (Esacrom Surgysonic) with Insert ES001 under continuous irrigation with sterile physiologic solution. • Trephine bur (TRE 02, Biomet 3i) on a low-speed handpiece (1,000 rpm) under continuous irrigation with sterile physiologic solution. The obtained bone blocks were milled manually (R. Quétin Bone Mill, Roswitha Quétin).

The entire study was conducted according to the principles of the Helsinki Declaration12 for experimentation in human subjects. Before entering into the study, all patients were informed about the design of the study, and informed consent was obtained. All patients (in both the preliminary study and the main study) satisfied the following entry criteria: age more than 18 years; no smoking habit; full-mouth plaque score and full-mouth bleeding score < 25% (four sites); absence of systemic disease and metabolic bone disorders; no current pregnancy; no history of malignancy, radiotherapy, or chemotherapy for malignancy in the past 5 years; no history of regenerative surgery in the experimental site; presence of severe maxillary atrophy (class V, Cawood and Howell13 and alveolar bone height between 2 and 4 mm evaluated by means of CT) (main study); and any extractions more than 1 month before sinus augmentation (main study). Any patients presenting with a reactive sinus membrane, cysts, or mucoceles (evaluated with CBCT, exposure time 20 seconds, acquisition window 24 × 14 cm, iCat Technology) were excluded from the main study.

As stated, samples were harvested from the posterior mandible. The bone scraper, round bur, and piezoelectric device were used superficially on the buccal side (cortical bone), and the implant bur and trephine bur collected both cortical and medullary bone. After harvesting, the samples were processed for histomorphometric analysis (see later section on sample preparation).

Preliminary Study

To conceal the treatment assignment from the investigator until harvest and application of the grafting materials was required, the central registrar instructed the investigator to assign a sealed envelope containing the treatment to the specific subject. This was performed immediately before surgery by faxing a subject registration form including the code of the envelope containing the treatment assignment and the letter encoding the evaluation group.

The preliminary study was designed to evaluate the features of bone autografts collected by five common procedures. Five patients who needed guided bone regeneration or sinus augmentation procedures were included in this study. After local anesthesia was accomplished, the graft harvesting required for the regenerative procedure was performed. Five bone samples were collected from

Main Study

Patient Selection and Randomization. A total of 20 patients with unilateral severe maxillary atrophy and a need for sinus augmentation were enrolled in the main study. After agreeing to participate in the study, each patient was randomly assigned to one of the following treatment regimens: • Group A: Sinus augmentation with autograft (30%) collected by trephine bur + Bio-Oss (Geistlich, Bio-Oss) (70%) • Group B: Sinus augmentation with autograft (30%) collected by bone scraper + Bio-Oss (70%)

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Maridati et al

Surgical Procedure. One hour before starting surgery, all patients received antibiotic prophylaxis with 2 g of amoxicillin and clavulanic acid. A two-stage sinus elevation technique according to Boyne and James14 was used in residual alveolar bone that was less than 5 mm high, and insertion of dental implants was postponed until 6 months after the augmentation surgery. To expose the buccal wall of the sinus, a midcrestal incision on the alveolar ridge was performed and vertical releasing incisions were made on the mesial and distal. A round diamond bur mounted on a low-speed handpiece and irrigated with saline solution was used to delineate a rectangle (approximately 2 cm wide, 1 cm high) on the bone surface with the lower border located around 2 mm above the sinus floor. After exposure of the sinus membrane, the operculum was delicately pushed inside the sinus by means of a Molt curette to create a cleavage between the membrane and the bone wall. The sinus mucosa was reflected and pushed vertically to reveal the subantral cavity. Autogenous bone was collected from the upper posterior part of the alveolar process using the trephine bur or the bone scraper, depending on the group assignment. The grafting material (including bone 30% and Bio-Oss small granules 0.25 to 1 mm) was then placed into the cavity. To determinate the correct ratio of autogenous and anorganic bovine bone, a specific bone measuring cup was used. A resorbable membrane was used to keep the graft in place and prevent an overly strict embrasure between the periosteum and the graft particles. An implant bed was prepared in the center of the edentulous area following the standard protocol for AstraTech implants, and one narrow implant was placed (3 × 11 mm) (AstraTech) in each augmented sinus. The surgical site was closed with 5/0 Gore-Tex sutures. Six months after augmentation, patients returned to the clinical center and underwent CBCT analysis. After local anesthesia and flap elevation, the clinician prepared the implant bed using a trephine bur (3 mm diameter, 8 mm length) and placed AstraTech implants for standard prosthetic rehabilitation. The narrow implant placed during augmentation was removed using a trephine bur (3 mm diameter, 8 mm length). These two bone biopsy samples—one that included the narrow implant (implant sample, I-S), and one without the implant (non–implant sample, NI-S)—were processed for undecalcified histologic examination and used for histomorphometric analysis.

Histomorphometric Analysis in Both Studies

Immediately after harvesting, all samples (from the preliminary study and the main study) were fixed in 10% formalin for 48 hours at room temperature and then dehydrated and included in resin (Kulzer Technovit

7200, Bio-optica). Sections 70 µm thick were obtained from the blocks containing bone samples using a bone microtome and a grinding machine (Remet). Finally, the samples were stained with toluidine blue/ pyronine G. Samples were observed with an optical microscope (Nikon Eclipse E600) equipped with a digital camera (DXM1200, Nikon). For each sample, pictures were taken at magnifications of ×2, ×4, ×10, and ×20. Images at ×2 and ×4 were used for panoramic overviews. Those at ×10 were used for analysis, which was performed with software for image analysis (Image J, U.S. National Institutes of Health), while the ×20 images served as controls. In the preliminary study histologic specimens, the features of the bone particles were analyzed. To be defined as “fragments,” the observed bone particles had to display a clearly identifiable lamellar structure, and at least one of the dimensions had to be greater than 100 µm.15 Three blinded and calibrated operators measured the percentage of area occupied by the target tissue after the conversion of the image into grayscale. For each microphotograph, vital bone fragments were recorded when osteocytes with clearly evident nuclei were detected in bone lacunae.16 Furthermore, fragments were differentiated by size; those with dimensions between 100 and 1,000 µm were classified as medium fragments (MF), fragments smaller than 100 µm were denoted as small fragments (SF), and those larger than 1,000 µm were termed large fragments (LF). The following parameters were calculated in the samples from the preliminary study. • Total surface area of the samples (BA) • Bone vitality, expressed as the percentage of bone surface containing lacunae with osteocytes with clearly recognizable nuclei • Mean surface area of fragments for each group (MA) • Total area and percentage area of MF for each group • Total area and percentage area of LF for each group • Total area and percentage area of SF for each group • Nonvital bone (NVB), the percentage of mineralized bone tissue that contained areas of empty osteocyte lacunae, and vital bone (VB), the percentage of mineralized bone tissue that contained osteocytes in lacunae For the specimens from the main study, the following parameters were analyzed: • Bone-to-implant contact (BIC): Percentage of implant length that contacts the bone tissue compared to the total implant length

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Figs 1a to 1f   Histologic microphotographs of the bone chips harvested during the preliminary study (toluidine blue/pyronine G).

50,000 µm

Fig 1a  Specimen harvested with the bone scraper. The lamellar bone structure was maintained, with osteocyte lacunae and osteocytes apparent (original magnification ×10).

100 µm

Fig 1b   The round bur produced a small quantity of bone sludge (original magnification ×10).

100 µm

Fig 1c  The implant bur resulted in particulate material with variable dimensions and shapes (original magnification ×10).

NV NV V

10,000 µm

100 µm

Fig 1d  The material harvested by the piezoelectric device consisted of small quantities of heterogenous fragments (original magnification ×10).

Fig 1e   The trephine bur produced large, mostly vital fragments with polygonal shapes and well-defined margins (original magnification ×10).

NV

V

V NV

V

V

NV

V

5,000 µm

Fig 1f  At higher magnification (original magnification ×60), nonvital lacunae (NV) and vital lacunae with osteocytes (V) were clearly detectable.

• Bone ingrowth: Percentage area of bone inside the implant threads • Point-counting technique according to the Delesse formula (VV PP) for NI-S to evaluate the tissue fraction of residual allograft material, regenerated bone, and medullary spaces

histomorphometric and radiographic data between the two experimental groups in the main study was performed with nonparametric statistical tests (Wilcoxon Mann-Whitney test). The level of significance was set at 5% (P < .05).

Radiographic Analysis (Main Study)

RESULTS

Patients in the main study underwent CBCT within 4 weeks before regenerative surgery, 1 week (T1) after surgery, and 6 months (T2) after surgery. To evaluate volumetric changes of the augmented area, T1 and T2 CBCT images were elaborated with a software system (Mimics, Materialise), as described elsewhere.17 The final (T2) volume of total graft (autograft + Bio-Oss) was compared to the initial (T1) volume of the total graft to calculate the percentage of graft remodeling.

Statistical Analysis in Both Studies

For each histologic (preliminary and main study) and radiographic parameter, the average and standard deviation were calculated. Comparison of

Preliminary Study

Five healthy male patients (mean age, 54 years) were recruited for this study. One patient dropped out for personal reasons; thus, 20 bone samples were harvested (a total of four samples for each harvesting procedure) and analyzed. Macroscopic and histologic features of bone chips from the different collection devices appear in Fig 1. Data from the preliminary study showed that bone chips harvested using the trephine bur and created by manually milling a bone block had a characteristic polygonal shape with welldefined margins and were mostly large and vital. The bone scraper collected a notable quantity of MF The International Journal of Oral & Maxillofacial Implants 1131

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Table 1  Histologic Characteristics (Mean Percentages ± Standard Deviations) of Bone Samples Harvested with Different Methods Bone scraper (n = 4)

Parameter

Round bur (n = 4)

Piezoelectric device (n = 4)

Trephine bur (n = 4)

30 (± 51)

0

77 (± 13)

% area of LF (> 1,000 µm)

16 (± 6)

% area of MF (100 to 1,000 µm)

78 (± 8)

37 (± 26)

43 (± 33)

72.20 (± 21)

22 (± 11)

6 (± 7)

63 (± 26)

27 (± 27)

27.80 (± 21)

1 (± 2)

% area of SF (< 100 µm)

0

Implant bur (n = 4)

LF = large fragments; MF = medium fragments; SF = small fragments.

% of specimen

NVB VB 100  90  80  70  60  50  40  30  20  10  0 

Bone scraper

Round bur

Implant bur

Piezo­ electric device

Trephine bur

and vital fragments, quadrangular and elongated in shape, with lamellar structure and osteocyte lacunae clearly detectable. Fragments obtained by means of the round bur were crushed, and only a few cells were identified in the tissue. The implant bur and the piezoelectric device mostly produced SF and less-vital bone particulates with highly variable and irregular shapes (Table 1, Fig 2). Since the trephine bur and the bone scraper produced a high amount of vital bone and MF/ LF, these techniques were compared in the main study.

Main Study

Fig 2   Percentages of vital (VB) and nonvital (NVB) bone tissue harvested by means of the five different methods.

Twenty patients were enrolled in the main study; however, two patients in group A (trephine bur) dropped out (one died, and one required treatment for prostate cancer). Thus, eight patients (five men, three women) with a mean age of 55 years were analyzed in group A, and 10 subjects (seven men, three women) with a mean age of 62 years were included in group B. For all patients, the residual alveolar crest averaged about 3 mm (range, 2 to 5 mm). No perforations of the sinus membrane occurred during surgeries. Only one infection occurred 15 days after surgery and was treated with amoxicillin and clavulanic acid (1 g every 12 hours for 6 days). All regenerative procedures were completed successfully, and after 6 months all patients underwent implant placement. Each patient received one to three implants, for a total of 34 implants placed.

Histologic Evaluations and Histomorphometric Results. Images of histologic specimens are shown in Figs 3 and 4. Bone biopsy samples without the narrow implant were used to evaluate the overall tissue structure and to calculate the volume fractions of biomaterial, regenerated bone, and medullary spaces. Tissue samples from both groups displayed a normal structure, and no inflammatory infiltration was apparent. In all patients, the biomaterial appeared to have partially remodeled. From among the remaining particles, a few were undergoing resorption, while most xenograft particles were surrounded by newly formed bone in different stages of maturation. Bridges of new bone connected the residual graft fragments (Figs 3a and 3b, Figs 4a and 4b). Biopsy specimens containing the small-diameter implants were used to assess implant osseointegration in the regenerated tissue (Figs 3c and 3d, Figs 4c and 4d). Data on volume fractions are illustrated in Fig 5. Statistical analysis showed no significant differences between groups A and B in terms of the amounts of residual biomaterial, regenerated bone, and medullary spaces. In group A, BIC and bone ingrowth were higher than in group B; however, the difference was not significant (Fig 6). Radiographic Observations. The CBCT images revealed volume contractions of 19.16% (± 4.76%) for group A and 20.09% (± 6.54%) for group B. The difference between groups was not statistically significant.

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Maridati et al

*

*

* * *

*

*

* *

* 50,000 µm

Fig 3a   Light microscopic overview of an NI-S specimen of group A. The grafted particles were surrounded by new lamellar bone (red arrows) in an active phase of mineralization (blue-violet). Inflammatory infiltrate was not observed (original magnification ×20; toluidine blue/pyronin Y).

Fig 3b  Light microscopic image of an NI-S/group A specimen showing numerous graft particles (asterisks) that have osseointegrated well and new bone bridges (violet) connecting the residual grafted particles (original magnification ×100; toluidine blue/pyronin Y).

Fig 3c  Overview of an I-S specimen from group A showing a well-osseointegrated implant in newly formed bone (blue-violet). Inflammatory infiltrate was not observed (original magnification ×20; toluidine blue/pyronin Y).

Fig 3d  Detail of the specimen shown in Fig 3c showing close contact between the implant and newly formed bone (original magnification ×200; toluidine blue/ pyronin Y).

DISCUSSION Selection of the appropriate grafting material for bone reconstruction in oral surgeries is crucial to the success of regenerative therapy. In bone defects treated with a mixture of autogenous bone and deproteinized bovine bone matrix, the vital autogenous bone acted as a source of bone morphogenetic proteins and of cells that stimulated bone metabolism and accelerated de novo bone formation.18,19 The particle size of grafted material also plays an important role in the regenerative process. Studies observed that large chips increase a graft’s space-maintaining effect and improve osteoblast attachment, but they may undergo bone sequestration or take a long time to be remodeled.10,20 To identify the best method to collect autografts, in the preliminary study, the vitality and dimensions of human bone particulate harvested by five common procedures were evaluated histologically and histomorphometrically. The results indicated that both the trephine bur and the bone scraper produced mostly

vital fragments of medium and large size, confirming data from previous in vitro and preclinical studies.9 Miron et al9 observed that tissue particles harvested with a bone scraper and trephine bur have a higher cell content, an increased ability to differentiate and produce mineralized tissue, and stronger expression of osteoinductive proteins (eg, bone morphogenetic protein-2 and vascular endothelial growth factor) and paracrine function than chips collected by piezoelectric device and implant bur.9 The bone scraper and trephine bur would seem to be the most appropriate harvesting instruments for bone regenerative therapies. However, from an anatomical and biologic point of view, tissue samples harvested using a trephine bur are composed of both cortical and medullary bone and are richer in cells and growth factors than those harvested using a bone scraper, which include only a cortical component.9,21 Translated into clinical practice, it may be postulated that different osteogenic and osteoinductive graft properties influence the success of regenerative and implant therapies. The International Journal of Oral & Maxillofacial Implants 1133

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* *

*

*

* Fig 4a   Overview of an NI-S specimen of group B showing incorporation of the grafted blocks (red arrows) within newly formed bone in different stages of mineralization (blueviolet). Wide medullary spaces were found spreading into the sample. Inflammatory infiltrate was not observed (original magnification ×20; toluidine blue/pyronin Y).

Fig 4c   Overview of an I-S specimen from group B showing an osseointegrated implant. The majority of implant threads were filled by bone marrow. No inflammatory infiltrate was observed (original magnification ×20; toluidine blue/pyronin Y).

40  30  20  10  0 

Fig 4d   Detail of one implant thread from group B filled with newly formed bone (original magnification ×200; toluidine blue/ pyronin Y).

BIC Bone ingrowth

60  % of specimen

% of specimen

50 

Fig 4b  Numerous grafted blocks (asterisks) osseointegrated well, and bridges of new bone (violet) connected the residual grafted fragments (original magnification ×100; toluidine blue/pyronin Y).

70 

Graft Regenerated bone Medullary spaces

60 

50,000 µm

50  40  30  20  10 

Group A

Group B

0 

Group A

Group B

Fig 5   Percentages of grafted particles, regenerated bone, and medullary spaces in tissue samples at 6 months after sinus augmentation.

Fig 6   Data on BIC and bone ingrowth after 6 months of healing.

The main study sought to determine whether autograft bone components (medullary/cortical) of the graft affect the healing and the volume contraction of a mixed bone autograft/xenograft (proportion 30:70)22 and the osseointegration of implants

placed in the context of a regenerative procedure. Upon analysis, both groups presented similar histomorphologic appearance: no inflammatory infiltrate, residual grafted particles undergoing resorption or surrounded by and in close contact with the newly

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formed mineralized tissue and new bone bridges connecting xenograft particles, and similar overall graft volume changes and implant osseointegration. All the current histomorphometric, histomorphologic, and radiographic results are in agreement with the literature.23–26 Based on the data of the present study, it seems that the medullary or cortical autogenous bone content within the grafted mixture does not affect the histologic features or amount of healed bone. This result does not agree with expectations from data of previous in vitro studies showing that chips obtained from trabecular bone have a greater regenerative potential than those obtained from cortical bone.3 It should be considered that, although the proportion of autogenous bone in the mixture used in the present research was higher than that reported in several studies (30%, instead of 20%),27 the Bio-Oss content (which was still 70% of the grafting material) may nevertheless have masked the biologic activity of the autogenous bone. Furthermore, tissue transplantation, and thus its exposure to hypoxia and to molecules in the grafted site, may alter cell viability and activity.28,29 The maxillary sinus membrane has an innate osteogenic potential30 that contributes to regeneration during the sinus augmentation procedure; furthermore, the surgical area underneath the membrane is isolated from the contaminated oral cavity. The osteogenic potential of grafted material may therefore play a minor role in the success of this therapy, whereas its physical properties of space maintenance and blood clot stabilization may be more important. For these reasons, the beneficial role of autogenous bone mixed with xenograft bone as a material for maxillary sinus augmentation and for implant survival is still controversial, and the use of pure xenograft material has been proposed.25,31 From a clinical point of view, during treatment, the bone scraper and trephine bur would seem to be interchangeable by the clinician. Although the bone scraper harvests only cortical bone, this method is less invasive than a trephine bur and can be freely chosen depending on the ability of the operator and on the anatomical area being treated.

CONCLUSION Data from this study confirm that the bone scraper and trephine bur are the most suitable tools to harvest autogenous bone for regenerative procedures. The biologic differences between the two bone particulates harvested by each method may not influence regeneration and osseointegration after sinus augmentation when mixed with xenograft bone.

ACKNOWLEDGMENTS The authors reported no conflicts of interest related to this study.

REFERENCES   1. Klijn R, Meijer G, Bronkhorst EM, Jansen J. A meta-analysis of histomorphometric results and graft healing time of various biomaterials compared to autologous bone used as sinus floor augmentation material in humans. Tissue Eng Part B Rev 2010;16:493–507.   2. Simion M, Dahlin C, Trisi P, Piattelli A. Qualitative and quantitative comparative study on different filling materials used in bone tissue regeneration: A controlled clinical st udy. Int J Periodontics Restorative Dent 1994;14:198–215.   3. Springer IN, Terheyden H, Geiss S, et al. Particulated bone grafts—Effectiveness of bone cell supply. Clin Oral Implants Res 2004;15:205–212.   4. Yamashita M, Nevins M, Jones AA, Schoolfield J, Cochran DL. A pilot experimental lateral ridge augmentation study using bone morphogenetic protein 2 in dogs. Int J Periodontics Restorative Dent 2010;30:457–469.   5. Triplett RG, Nevins M, Marx RE, et al. Pivotal, randomized, parallel evaluation of recombinant human bone morphogenetic protein-2/ absorbable collagen sponge and autogenous bone graft for maxillary sinus floor augmentation. J Oral Maxillofac Surg 2009;67: 1947–1960.   6. Jensen T, Schou S, Gundersen HJ, Forman JL, Terheyden H, Holmstrup P. Bone-to-implant contact after maxillary sinus floor augmentation with Bio-Oss and autogenous bone in different ratios in mini pigs. Clin Oral Implants Res 2013;24:635–644.   7. Nkenke E, Stelzle F. Clinical outcomes of sinus floor augmentation for implant placement using autogenous bone or bone substitutes: A systematic review. Clin Oral Implants Res 2009;20:124–133.   8. Chiriac G, Herten M, Schwarz F, Rothamel D, Becker J. Autogenous bone chips: Influence of a new piezoelectric device (Piezosurgery) on chip morphology, cell viability and differentiation. J Clin Periodontol 2005;32:994–999.   9. Miron RJ, Gruber R, Hedbom E, et al. Impact of bone harvesting techniques on cell viability and the release of growth factors of autografts. Clin Implant Dent Relat Res 2013;15:481–489. 10. Berengo M, Bacci C, Sartori M, et al. Histomorphometric evaluation of bone grafts harvested by different methods. Minerva Stomatol 2006;55:189–198. 11. Erpenstein H, Diedrich P, Borchard R. Preparation of autogenous bone grafts in two different bone mills. Int J Periodontics Restorative Dent 2001;21:609–615. 12. World Medical Association. Declaration of Helsinki: Ethical principles for medical research involving human subjects. 1964. http:// www.wma.net/en/30publications/10policies/b3/. Accessed 29 October 2014. 13. Cawood J, Howell R. A classification of the edentulous jaws. Int J Oral Maxillofac Surg 1988;17:232–236. 14. Boyne PJ, James RA, Grafting of the maxillary sinus floor with autogenous marrow and bone. J Oral Surg 1980;38:613–616. 15. Shapoff CA, Bowers GM, Levy B, Mellonig JT, Yukna RA. The effect of particle size on the osteogenic activity of composite grafts of allogeneic freeze-dried bone and autogenous marrow. J Periodontol 1980;51:625–630. 16. Pejrone G, Lorenzetti M, Mozzati M, Valente G, Schierano GM. Sinus floor augmentation with autogenous iliac bone block grafts: A histological and histomorphometrical report on the two-step surgical technique. Int J Oral Maxillofac Surg 2002;31:383–388. doi:10.1054/ ijom.2002.0286. 17. Dellavia C, Speroni S, Pellegrini G, Gatto A, Maiorana C. A new method to evaluate volumetric changes in sinus augmentation procedure. Clin Implant Dent Relat Res 2014;16:684–690.  18. Galindo-Moreno P, Avila G, Fernandez-Barbero JE, et al. Evaluation of sinus floor elevation using a composite bone graft mixture. Clin Oral Implants Res 2007;18:376–382.

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Maridati et al

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Histologic and Radiographic Comparison of Bone Scraper and Trephine Bur for Autologous Bone Harvesting in Maxillary Sinus Augmentation.

Purpose: The aims of this study were to investigate the best two of five common methods of collecting autologous bone (preliminary study [PS]) and to ...
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