الفهرس 
Volumetric And Linear Assessment Of Maxillary, Mandibular And Zygomatic Bone As Donor Sites For Alveolar Ridge Augmentation Using Cbct. A Cross Sectional Study
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Abstract
Autogenous bone grafts remains the gold standard in the repair of alveolar
atrophy and in bone defects reconstruction
Intraoral bone grafts from the mandible and maxilla can be applied. The maxilla
provides only small amounts of mainly cancellous autograph like zygomatic buttress
and maxillary tuberosity. However, Mandibular bone grafts have been used for
alveolar repair to allow implant placement with extremely favorable results in bothhorizontal
and mainly vertical bone deficiency. Mandibular block can be harvested
from the ramus, the mandibular symphysis, or edentoulous areas.
The obvious advantages associated with intraoral harvesting includes: easy and
convenient surgical accessibility, The close proximity of donor and recipient sites can
reduce operative and anesthesia time, making them ideal for outpatient implant
surgery, low rate of morbidity, decreased cost and not result in avisible scar.
An important advantages in implant cases is that Autogenous graft obtained
from intramembranous bone has been demonstrated to be more resistant to resorption
than bone grafts obtained from endochondral bones i.e minimal resorbtion, good
volume maintenance, and high concentration of bone morphogenetic proteins.
CBCT imaging is a well-established radiographic modality in treatment
planning for dental implants and for the individual patient has to be used primarily for
presurgical planning and transfer to implant placement. The justification for CBCT
use during the preoperative planning phase is based on the need for specific anatomic
considerations, esthetic challenges in the anterior maxilla, insufficient bone volume,
shape and quality, the use of more advanced surgical techniques and the integrated Autogenous bone grafts remains the gold standard in the repair of alveolar
atrophy and in bone defects reconstruction
Intraoral bone grafts from the mandible and maxilla can be applied.The maxilla
provides only small amounts of mainly cancellous autograph like zygomatic buttress
and maxillary tuberosity. However, Mandibular bone grafts have been used for
alveolar repair to allow implant placement with extremely favorable results in bothhorizontal
and mainly vertical bone deficiency. Mandibular block can be harvested
from the ramus, the mandibular symphysis, or edentoulous areas.
The obvious advantages associated with intraoral harvesting includes: easy and
convenient surgical accessibility, The close proximity of donor and recipient sites can
reduce operative and anesthesia time, making them ideal for outpatient implant
surgery, low rate of morbidity, decreased cost and not result in avisible scar.
An important advantages in implant cases is that Autogenous graft obtained
from intramembranous bone has been demonstrated to be more resistant to resorption
than bone grafts obtained from endochondral bones i.e minimal resorbtion, good
volume maintenance, and high concentration of bone morphogenetic proteins.
CBCT imaging is a well-established radiographic modality in treatment
planning for dental implants and for the individual patient has to be used primarily for
presurgical planning and transfer to implant placement. The justification for CBCT
use during the preoperative planning phase is based on the need for specific anatomic
considerations, esthetic challenges in the anterior maxilla, insufficient bone volume,
shape and quality, the use of more advanced surgical techniques and the integrated
presurgical planning and virtual patient approach.
In our study, the planmeca promax 3D Mid machine were used to assess the
four intraoral graft sites in-vivo using linear and volumetric measurements (manual or
semi-automatic segmentation techniques). Linear measurments are important for
identifying the bounderies and anatomical structures very well
Manual segmentation was done for 3 donor site and semiautomatic
segmentation only for maxillary sinus.
Usually a small defect is 7 mm in width, 5 mm depth, and 12 mm length and it
requires a volume of 0.42ml. Maxillary donor sites in this current study, with the
resultant widths (6.68±0.44 and 19.12±3.47) and volumes (0.31±0.07 and 0.49±0.06)
may conform to such small deficiencies.
According to our findings, for medium and large defects, the ramus might be
adequate with width and volume of 29.87±6.17 mm and 0.99±0.19 cm3 respectively,
whereas, the symphysis may cover large defects, since it supplies a mean graft width
and volume of 40.17±0.96 mm and 1.56±0.44 cm3.
the mandibular symphysis is dominating the other areas regarding the
volume as was observed in the mesio-distal dimension,
The thinnest graft was the zygomatic buttress, care should be taken in
consideration to avoid schneiderian membrane perforation.
The volume in the current study was done in two ways, volumes calculated
from linear measurements and volumes extracted by the segmentation tool. The error
between the two volume techniques in the four groups was relatively wide ranging
from 23 to 61 %, where segmentation showed underestimated values.