Microarchitecture of the Augmented Bone Following Sinus Elevation
Condition: Alveolar Bone Loss; Sinus Pneumatization; Edentulous; Alveolar Process, Atrophy
MeSH terms: Alveolar Bone Loss
Study type: Interventional

Summary: 
      In this prospective randomized clinical study sinus floor elevation procedures are preformed
      using different biomaterials with the lateral window technique. After a 6-month healing, at
      the time of dental implant placement bone core biopsy samples are harvested. The samples
      undergo micro-Ct and histomorphometric analysis.
    

Detailed description: 
      Aim of the study The aim of this prospective randomized study is to evaluate the remodeling
      capacity of albumin impregnated freeze-dried bone allograft in sinus floor augmentation by
      histomorphometry and micro-CT analysis and to compare it to anorganic bovine xenograft
      material.

      Surgical methods Patients performed oral rinse with 0.2% chlorhexidine solution for 1 min
      before surgery. Under local anesthesia a full thickness flap was raised from a midcrestal
      incision along with two relieving incisions. Lateral window osteotomies were carried out with
      diamond burs. The Schneiderian membrane was carefully elevated. Bone graft material was
      packed in the defect with light force. Patients were randomly assigned to 2 groups based on
      the type of bone filler: albumin impregnated allograft (BoneAlbumin, OrthoSera GmbH, Krems an
      der Donau, Austria) or anorganic bovine bone mineral (ABBM), (Bio-Oss Geistlich Wolhusen,
      Switzerland). A porcine collagen membrane (Bio Gide, Geistlich GmbH, Wolhusen, Switzerland)
      was placed over the lateral window and fixed by titanium pins (Titan Pin Set, Ustomed
      Instruments Ulrich Storz GmbH & Co. KG, Tuttlingen, Germany). The buccal flap was mobilized
      to allow tension-free primary closure. The margins were stabilized with single interrupted
      sutures. Antibiotics (1 g amoxicillin-clavulanate twice a day for 5 days, or in case of side
      effects or known allergy to penicillin, 300 mg clindamycin 4 times a day for 4 days),
      anti-inflammatory drugs (50 mg diclofenac 3 times a day for 3 days), and chlorhexidine
      mouthwash (twice a day for 21 days from the first day after surgery) were prescribed. Sutures
      were removed after 10 days. After 6 months healing surgical re-entry procedure took place
      under local anesthesia. A bone core biopsy was taken with a trephine with an external
      diameter of 3.5 mm and an internal diameter of 2.5 mm (330 205 486 001 025 Hager & Meisinger
      GmbH, Neuss, Germany) and implants of at least 4.0 mm of diameter were placed into the
      grafted alveolus nonsubmerged.

      Histomorphometry Bone core biopsy material was fixed in 10% buffered formaldehyde solution.
      Following decalcination and dehydration, the biopsy material was embedded in paraffin and 20
      µm sections were prepared. The sections were stained with routine haematoxylin eosin stain.
      Sections were evaluated under a light microscope in magnification 40×-400× .

      Histomorphometric measurements were completed on sections with Panoramic Viewer 1.15
      (3DHISTECH Ltd., Budapest, Hungary) using a combination of Adobe PhotoShop (Adobe System
      Inc., San Jose, CA, USA) and ImageJ, the public domain NIH Image program (US National
      Institutes of Health' http://rsb.info.nih.gov/nih-image/) at 150× magnification. Two slides
      of the augmented areas in each bone core biopsy sample were evaluated to record area
      percentage of newly formed bone, residual particles of the bone graft material, and the bone
      marrow space according to published protocols. Histomorphometric data consisted of the area
      percentage of newly formed bone, residual particles of the graft material and bone marrow
      were identified in each section.

      Micro-CT analysis The bone core biopsy samples were scanned using a microcomputed tomography
      (μCT) scanner (Skyscan 1172 X-ray microtomograph, Bruker µCT, Kontich, Belgium). After the
      acquisition, raw images were reconstructed using NRecon software (v.1.7.1.6., Bruker µCT,
      Kontich, Belgium). The morphometric variables relevant to our study calculated by CTAn
      software (v.1.17.7.2, Bruker µCT, Kontich, Belgium). On the reconstructed images of each
      sample the demarcation plane of the host and the augmented area was identified and the
      complete available tissue (maxilla or augmented bone, respectively) were selected as regions
      of interest (ROIs) for quantitative analysis.

      Micromorphometric data was collected by evaluation of the augmented bone of the test or
      control group. Additional micromorphometric data was recorded by analyzing the native bone of
      the alveolar ridge within the bone core biopsy samples of both test and control group. The
      microarchitectural parameters of the augmented bone of the BoneAlbumin group and the ABBM
      group; the augmented bone of the BoneAlbumin group and the native bone of the alveolar ridge;
      the augmented bone of the ABBM group and the native bone of the alveolar ridge were compared.

      Statistical analysis Percentage values of each bone core biopsy sample were used to calculate
      descriptive statistics for the histomorphometrical and quantitative µCT analysis. The results
      were analyzed statistically using the IBM SPSS Statistics 23 data analysis software program
      (IBM Corporation, New York, NY. USA). The Kruskal Wallis One-way ANOVA test was used to
      compare two sets of data for the statistical analysis of the histomorphometric results.
      One-way ANOVA test was used to compare three sets of data for the statistical analysis of the
      micromorphometric results of the micro-CT. Values of p < 0.05 were considered statistically
      significant.

      CBCT CBCT imaging (PaX-Reve3D, Vatech, Hwaseong, South-Korea) was carried out prior to sinus
      floor elevation to evaluate the anatomy and possible pathology of the maxillary sinuses, then
      6 months after bone augmentation prior to implant placement (preoperative CBCT), and 3 years
      after implant placement (postoperative CBCT). To register the preoperative and postoperative
      CBCT data by anatomical landmarks 3DSlicer 4.10.2 software (The Brigham and Women's Hospital,
      Inc. Boston, USA) was used. The ROIs were identified by determining the central axis of the
      implants and placing a virtual cylinder on the preoperative CBCT image sequence with a
      diameter of 2,5 mm and the length of 8 mm on this axis corresponding with the inner
      dimensions of the trephine used for bone core biopsy harvesting. The image sequences of
      selected ROIs were imported in CTAn software (v.1.17.7.2, Bruker micro-CT, Kontich, Belgium)
      and micromorphometric variables were calculated by the software.

      Statistical analysis of CBCT results Correlation of the micromorphometric data obtained from
      the CBCT images and micro-CT images was determined by The Spearman's rank-order correlation.
      Statistical analysis was performed using the IBM SPSS Statistics 25 data analysis software
      program (IBM Corporation, New York, USA). Values of P < 0.05 were considered statistically
      significant.
    

Intervention name(s): sinus floor elevation; bone core biopsy; dental implant placement; Cone Beam Computed Tomography scans (CBCT)
Intervention type(s): Procedure; Procedure; Device; Diagnostic Test
Intervention description(s): sinus floor elevation with the lateral technique; After 6 month healing time reentry took place and bone core biopsy samples were collected from the augmented bone of the maxillary sinuses with a trephine drill. Biopsy samples were collected from the sites where the dental implants were to be placed.; During reentry after bone biopsy dental implants were placed.; Preoperative CBCT scans are carried out before dental implant placement, 6 months after sinus floor elevations. Postoperative CBCT scans are taken 3 years after sinus floor augmentations.
Other intervention name(s): maxillary sinus augmentation
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: cone beam computed tomography (CBCT); microcomputed tomography (micro-CT); histomorphometry; sinus floor elevation; allograft; xenograft