Severe periodontitis, trauma, and long-term edentulism can cause significant resorptive
alterations of the alveolar ridge, leading to severe bone defects in the esthetic zone.
Careful hard and soft tissue evaluation prior to implant surgery is important to restore
proper function and esthetics. Horizontal, vertical, or combined ridge defects after
extraction significantly influence dental implant placement and its long-term stability,
as well as the final esthetics outcome.
Under natural conditions following a tooth extraction, the alveolar bone around the empty
socket would undergo resorption and the alveolar ridge would recede in height and width.
Besides leading to aesthetic and functional issues, the reduced bone volume would also
cause insufficient support to the dental implant, causing the implant to become loose and
unstable. For patients facing such issues, alveolar ridge augmentation is necessary to
regenerate the bone tissue and restore the alveolar ridge so as to ensure the long-term
stability of the implant.
Although a large number of alloplastic, allogenic or xenogenic bone substitute materials
are available for reconstruction of the alveolar crest, the use of autogenous bone is
still considered the gold standard. Autogenous bone has excellent osteoinductive,
osteoconductive and osteogenetic characteristics; immunological reactions or the
transmission of diseases can be safely avoided, and predictable augmentation results can
be obtained.
For several years, the use of dentin as an alternative autogenous material for alveolar
crest reconstruction and the grafting of bone deficits has been described and
investigated in animal experiments and clinical studies. Dentin is a suitable grafting
material because it is very similar to bone in its organic and inorganic composition.
Similar to the alveolar bone, about 90% of the organic substance of dentin consists of
type I collagen. Also, osteogenetically relevant structural proteins, such as
osteocalcin, osteonectin, phosphoprotein and sialoprotein, can be found in dentin.
Moreover, dentin contains osteogenetically active factors, including bone morphogenetic
protein 2 (BMP-2), tissue growth factor-ß (TGF-ß) and insulin- like growth factor-2
(IGF-2). As in alveolar bone, the inorganic components of dentin consist of various
calcium phosphates such as hydroxylapatite, ß-tricalcium phosphate, octacalcium phosphate
and amorphous calcium phosphate. Compared with autogenous bone, the use of dentin offers
the advantage of avoiding the harvesting procedure and the possible resulting donor site
morbidity with promising clinical and histological results owing to its inherent
osteoinductive and osteoconductive capacity. In comparison to autogenous bone block
graft, dentin grafts also show significantly less resorption.
However, autogenous dentin graft has limitations despite its proven bone-formation
capacity: dependence of the quantity on the number of teeth indicated for extraction and
the condition of the extracted teeth, lack of a standard method to process autogenous
dentin graft, and patient preference. Therefore, the application of dentin graft material
from other individuals- allogeneic dentin graft-has been considered as an alternative
autogenous dentin graft. Allo-dentin graft was conceptualized from the demineralized bone
matrix, which was largely developed and defined for the bone induction principle, which
states that a protein macromolecule in dentin and bone induces the differentiation of
mesenchymal cells into osteoblasts; this was postulated by Urist in 1965. The Allo-dentin
graft is a refined allograft that has osteoinductivity and has been clinically used since
the 1980s. Very few studies have investigated the application of Allo-dentin graft as
bone substitutes for bone graft surgery. The narrative review of revealed that
Allo-dentin graft has demonstrated a great potential for osteoinductivity in
extraskeletal sites, maximum clinical safety and efficacy without antigenicity nor
provoked immunologic reactions.
Cone beam computed tomography (CBCT) imaging developments went hand in hand with the
increasing use of 3D imaging applications for presurgical planning and transfer of oral
implant treatment. The main reasons for the triumph of CBCT are its capabilities of
volumetric jaw bone imaging at reasonable costs and doses, with a relative advantage of
having a compact, affordable, and nearby equipment. For the clinicians involved in
implant rehabilitation, the power of a dental 3D dataset is not only situated in the
diagnostic field, but also in the potential of gathering integrated patient information
for presurgical and treatment applications related to oral implant placement. Nowadays,
rapid advances of digital technology and computer-aided design/computer-aided
manufacturing (CAD/CAM) systems are indeed creating challenging opportunities for
diagnosis, surgical implant planning and delivery of implant-supported prostheses.
Segmenting organs and tissues to create 3-dimensional models is a useful technique for
diagnosis, surgical planning, and simulation. This technique is also applicable to the
planning of 3D-ridge augmentation, which plays a significant part in oral and
maxillofacial surgery. Segmentation enables accurate measurement of the ridge volume,
providing clinicians with quantitative insight into changes caused by cysts and tumors.
In addition, accurately segmenting provides valuable guidance for clinicians when
planning ridge augmentation during implant surgery. Although manual segmentation can be
used for this purpose, it is time-consuming and dependent on the practitioner's
experience due to high inter and intra-observer variability on CBCT images. While
artificial intelligence (AI) segmentation is generally more successful and easier to
perform than manual segmentation.
In the current study, AI-assisted 3D ridge augmentation of combined vertical and
horizontal deficient ridges utilizing allogenic dentin block versus allogenic dentin
shell graft will be assessed.