GTR

1. IMPLANT SITE DEVELOPMENT USING
TITANIUM MESH IN THE MAXILLA: A
RETROSPECTIVE STUDY OF 58 MESH
PROCEDURES IN 48 PATIENTS
Robert A Levine et al,2022
THE INTERNATIONAL JOURNAL OF
PERIODONTICS & RESTORATIVE
DENTISTRY

2. ABSTRACT
• This article presents a retrospective case series of implant site development using titanium
mesh (Ti-mesh) in the maxilla.
• A total of 58 mesh procedures in combination with several different bone grafts (allograft,
cellular allograft, and bovine xenograft) and biologics (including recombinant human
platelet-derived growth factor, autogenous platelet-rich growth factor, and recombinant
human bone morphogenetic protein-2) were performed in 48 patients.
• Ti-mesh guided bone regeneration procedures were performed 2 to 3 months after
extraction of non restorable/hopeless teeth, and the implants were placed 6 to 8 months
post augmentation.
• The mean initial ridge width was 2.0 ± 1.0 mm, and the mean horizontal gain after Ti-
mesh procedures was 4.7 ± 1.6 mm.
• The ridge width was first measured on the cross-sectional presurgical CBCT image and
then confirmed clinically during surgical procedures.

3. • No statistical difference in the horizontal gain was found among different
combinations of bone grafts and biomaterials.
• Ti-mesh exposure occurred 22% of the time. The middle-aged adults (odds
ratio [OR] = 8.59; P = .046) and older adults (OR = 16.66; P = .02) had
significantly higher chances of mesh exposure compared to young adults.
• While all implants were successfully placed, about 56% of the implants had <
2 mm of bone to the facial aspect of the osteotomy and received additional
contour augmentation when placed in a prosthetically appropriate position for
a screw retained restoration.
• This study demonstrates that although Ti-mesh procedures result in significant
bone regeneration in narrow alveolar ridges to predictably allow implant
placement, the age-related mesh exposure rate and frequency of need for
additional contour grafting should be discussed with patients.

4. INTRODUCTION
• Severe alveolar ridge defects present a challenge because the bone deficiency
may make implant therapy extremely difficult or sometimes impossible.
• Bone augmentation procedures to rebuild alveolar ridge width and height at
the implant sites are necessary for long-term esthetic and functional
outcomes.
• Both horizontal and vertical bone augmentation can be achieved with varying
results using several well-established techniques, various bone grafts, and
biologics.
• No matter the approach selected, all techniques must meet the three main
principles of regeneration: primary intention healing, space provision, and
wound stability

5. • A positive esthetic outcome is critical in the reconstruction of an edentulous ridge, and it
only happens when tooth replacement results in harmony with the remaining natural
dentition upon smiling.
• Several key factors should be assessed during planning and executed during treatment to
achieve excellent final esthetics: an esthetic risk assessment analysis, ≥ 2 mm of bone
facial to the implant after placement, and facial soft tissue that is ideally ≥ 2 mm thick.
• This thick buccal bone, which could be obtained through contour augmentation upon
implant placement, becomes increasingly important and beneficial in the esthetic zone.
• The use of a titanium mesh has been utilized since the mid-1980s.
• While Ti-mesh is not cell-exclusive, it shows promise through provision of enhanced
space maintenance, stabilization of the blood clot, and graft revascularization.
• The effectiveness of Ti-mesh in implant site development has been well documented,
showing substantial bone augmentation in both horizontal and vertical directions.

6. • The present retrospective study reviews the clinical results of bone
augmentation in the maxillae with three representative cases utilizing a
Ti-mesh scaffold to achieve a prosthetically driven implant placement.
• Data regarding the frequency and need for buccal contour grafting upon
prosthetically driven implant placement are also included.

7. GENERAL REVIEW

8. • INTRODUCTION OF GTR TO GBR
• ROLE OF BIOLOGIC MEDIATORS- CLINICAL EXAMPLE
• TITANIUM MESH – PROPERTIES,IMPORTANCE OF PORE SIZE
• HOW IS IT DIFFERENT FROM OTHER BARRIER MEMBRANES
• CURRENT APPLICATION OF TITANIUM MESH IN BONE
AUGMENTATION
• COMPLICATIONS OF TITANIUM MESH, MANAGEMENT, AND
PREVENTION
• HOW TO SELECT REPLACEMENT GRAFTS FOR VARIOUS
PERIODONTAL AND IMPLANT INDICATIONS
• GRAFT USED FOR REGENERATION
• ABOUT BIOLOGICS USED IN THIS STUDY

9. GTR GBR

10. Defect site What is to be achieved ?

12. ROLE OF BIOLOGICAL MEDIATORS?
1. MIGRATION
2. DIFFERNTIATION
3. PROLIFERATION
4. SYNTHESIS OF
EXTRACELLULAR
MATRIX

13. TITANIUM MESH
• The theory of GBR technology is to selectively prevent epithelial cells and
connective tissue cells from bone defect area through barrier membrane based
on different migration rate of various cells, allowing osteoblasts preferentially
enter the bone defect area to complete bone induction and regeneration.
• Meanwhile, bone graft materials are placed in the bone defect area as
scaffolds, and guiding osteoblasts and osteocyte to form new bone.
• If the bone grafts in the defect area lack support, it may be forced to shift by
local stress, resulting in the collapse of bone-augmented area, which cannot
achieve the expected effect.
• Therefore, for the barrier membranes in GBR technology, on the premise of
good biocompatibility, it is ideal to have sufficient stiffness, supportability,
and retention capacity.

14. • However, although traditional barrier membranes (such as absorbable
collagen membrane, nonabsorbable expanded polytetrafluorethylene
membrane (ePTFE), etc.) have the property of cell-selective isolation, they
are relatively soft and difficult to provide adequate retention and protection
for the bone regeneration areas.
• Hence, when the traditional barrier membranes be applied to large bone
defects, limited by its stiffness, it is difficult to maintain a suitable and stable
bone regeneration space, and is easy to generate micromotion that affects
blood supply.
• When the alveolar bone has severe vertical or horizontal bone defects, many
clinical studies suggest that titanium mesh shows superior mechanical
properties and great osteogenic performance during application.

15. PROPERTIES OF TITANIUM MESH
• Titanium is widely used in surgical operations due to its high stiffness, low density, corrosion resistance,
and good biocompatibility characteristics as a GBR barrier membrane for bone augmentation.
MECHANICAL
BIOLOGICAL
PROPERTIES AND
OSTEOGENIC
PROPERTY

16. MECHANICAL PROPERTIES
• Titanium mesh has good mechanical properties, its high strength and
stiffness enable space support for osteogenesis, its stability is necessary
to maintain bone graft volume during wound healing, and the elasticity
can reduce the oppression of oral mucosa.
• Due to its good plasticity, titanium mesh can adapt to various bone
defects through bending and shaping.
• These features enable GBR with titanium mesh to show a high stable
osteogenesis effect, and achieve coinstantaneous bone augmentation in
horizontal and vertical directions.

17. • For different titanium mesh, the thickness and porosity are the key factors
affecting its mechanical properties.
• Study suggested that the thickness of titanium mesh may affect the total
amount of new bone formation, while the pore size may affect the
proportion of bone tissue and soft tissue formation under titanium mesh.
• The thickness of titanium mesh is directly proportional to its mechanical
properties, which commonly used ranges from 0.1 to 0.6mm currently.
Usually, the titanium mesh at 0.2mm can be suitable for most instances.
• Under this thickness, titanium mesh can provide sufficient stiffness to
maintain space and protect grafts, while offer appropriate flexibility that
reduces the risk of tissue rupture.
• With the increase of reconstruction area of alveolar ridge, thicker titanium
mesh should be used in GBR to maintain bone regeneration space.

18. • As for thick titanium mesh, there are often some sharp edges in the process
of bending titanium mesh due to the decrease of plasticity, which is closely
related to the mucosal rupture titanium mesh exposure, many researches
focus on finding a more suitable thickness of titanium mesh.
• A study showed that 100–200 μm is the ideal thickness of titanium mesh to
reconstruct a large number of bone defects.
• Consistent with the result, Rakhmatia et al. compared the bone
augmentation effect with titanium mesh at 20, 50, and 100 μm in mouse
model and concluded that compared with thinner Ti-mesh, the use of
titanium mesh at 100 μm can achieve more extensive bone regeneration
effect.

19. IMPORTANCE OF PORE SIZE ?
• In terms of pore size, it also affects the performance of titanium mesh during bone
augmentation.
• The pore of the titanium mesh is thought to play an essential role in establishing
blood supply and facilitating metabolic processes of the grafts at the defect site.
• Celletti et al. demonstrated that without pores on titanium mesh, exposure of the
mesh would occur in 3 weeks after surgery.
• However, the relationship between the pore size of titanium mesh and bone
formation is still controversial. For the existence of pores on titanium mesh, it is
difficult to achieve selective cell isolation, and soft tissue often grow under titanium
mesh.
• Therefore, many studies have attempt to investigate the relationship between the
pore size and the amount of soft tissue growth.

20. • A study suggested that compared to the titanium mesh with small diameter
(0.6 mm), the titanium mesh with large diameter (1.2 mm) promoted more
bone regeneration and prevented soft tissue growth more effectively.
• This phenomenon may be related to the increased distribution of blood
supply, and diffusion of nutrients and oxygen leaded by the large aperture.
• On the contrary, a study showed that the use of titanium mesh with large
diameter (>2mm) may lead to more soft tissue growth upon the surface of
new bone than the use of titanium mesh with small diameter.
• A similar result for GBR with polyester meshes in different pore size may
explain this contradictory phenomenon: the larger the pore size of the barrier
membrane, the more connective tissue grows between the membrane and the
regenerated bone, and the more rapid bone regenerate, while the pore size
does not make much difference to the amount of bone formation after the
osteogenesis stabilized

21. BIOLOGICAL PROPERTIES AND
OSTEOGENIC PROPERTY
• Titanium mesh has good biocompatibility and can be compatible with
tissues.
• The biocompatibility of materials can be divided into corrosion resistance
and cytotoxicity.
• Due to its low electrical conductivity, titanium is prone to perform
electrochemical oxidation to form a passive and inert oxide layer.
• This oxide layer can be retained under the pH of human body, leading to
high and persistent corrosion resistance in titanium.
• Hence, little amount of metal particles can be released from titanium mesh,
while the titanium particles has no significant effect on human cells’ relative
growth rate.

22. • Study observed that after alveolar ridge reconstruction conducted by
titanium mesh, a thin layer of 1–2mm thick, soft tissue can often be found
upon the regenerated bone surface, called “pseudo-periosteum”.
• The formation of this soft tissue layer may be related to the insufficient
cell exclusion ability of titanium due to its pores.
• The role of pseudo-periosteum may be related to bone graft protection,
graft infection prevention, and absorption.
• Currently, it is often be removed with titanium mesh in subsequent
operation.

23. • According to the currently reported literature, GBR with titanium mesh has
strong osteogenesis predictability, and both horizontal and vertical bone
augmentation can be obtained in the process with delayed or simultaneous
implantation.
• In the delayed implantation strategy of bone augmentation, most researchers
have gained an average bone augmentation of 4–5mm in bone width and 5–
7mm in bone height.
• While in the strategy of simultaneous implantation with bone augmentation,
although there are few researches about three-dimensional bone increment,
the realization of ~3–4mm average bone gain in width and height seems
feasible.
• However, a meta-analysis about the horizontal or vertical bone
augmentation effect of titanium mesh could not be performed for the
heterogeneity of the data.

24. DIFFERENCES WITH OTHER BARRIER MEMBRANES
• The barrier membranes commonly used in clinical can be divided into absorbable
and nonabsorbable membranes according to their absorbability.
• The main absorbable membrane is collagen membrane, and the main nonabsorbable
membranes are ePTFE, titanium-reinforced PTFE, and titanium mesh.
• Among the barrier membranes mentioned above, titanium mesh is the only one
entirely made of metal.
• It exploit the advantages of titanium in mechanical and biological properties to the
full, performing excellent in space maintenance and bone reconstruction.
• In comparison, though some enhanced absorbable collagen membranes can provide
spatial protection to the bone graft material at the initial placement, they will
gradually degrade with the absorption of the membrane, making them unable to
achieve the same spatial maintenance ability as titanium mesh.

25. • Konstantinidis et al. compared the effect of collagen membrane and titanium
mesh in the vertical bone augmentation, and found that the collagen
membrane group gained 2.77 ± 1.97mm bone height, and the titanium mesh
group gained 4.56 ± 1.74mm bone height (p < 0.05),which can be considered
that titanium mesh has certain advantages in bone augmentation effect.
• Although Cucchi et al. proved that there is no significant difference (p <0.05)
between titanium mesh and titanium-reinforced PTFE in vertical bone
augmentation and complication rates.
• Researches showed that different from absorbable membranes or other
nonabsorbable barrier membranes like ePTFE, it is rare to observe
consequent infection of bone regeneration failure in bone augmented sites
after exposure of titanium mesh.

26. • This may be related to the dense and surface structure of titanium that is less susceptible to
be adhered by bacteria, and the protective effect of pseudo-periosteum formed under
titanium mesh.
• Due to the presences of pores, titanium mesh may lead to spontaneously heal of mucosa
upon bone reconstruction area after exposure, which means unlike ePTFE or titanium-
reinforced PTFE, it may not need to remove titanium mesh immediately as there is no
infection after mesh exposure.
• However, titanium mesh also has shortcomings. Unlike absorbable membranes, titanium
mesh cannot be resorbed by the body, which means the titanium mesh and fixation screws
need to be removal through second-stage surgery, causing trauma to the patients.
• Besides, different form other absorbable and nonabsorbable barrier membranes, due to its
stiffness, titanium mesh needs to be shaped during surgery to adapt profile of alveolar
ridge.
• This process is technically sensitive, time-consuming, and laborious. And the sharp edges
will inevitably form during bending, which may stimulate the mucosa, leading to mucosal
rupture and exposure of titanium mesh.

27. CURRENT APPLICATION OF TITANIUM
MESH IN BONE AUGMENTATION
INDICATIONS OF TITANIUM MESH
• GBR technique with titanium mesh was initially used to fix bone defects for
maxillofacial bone reconstruction. Gradually, it is applied to bone reconstruction on
alveolar bone defects.
• Currently, there are various clinical procedures for bone augmentation with titanium
mesh, which can be roughly divided into
1.Titanium mesh bone augmentation in simultaneous implantation
2.Titanium mesh bone augmentation with delayed implantation, and
3.GBR with titanium mesh in combination with other bone augmentation methods.

28. • For selecting different bone augmentation procedures
with titanium mesh, under the premise of the patient’s
general condition assessment, the operative area’s
alveolar bone defect should be evaluated in detail.
• Based on the Terheyden classification, the alveolar
ridge defects after tooth extraction can be divided into
four types according to the relationship between the
bone defect and the expected implantation site.The
specific classification is as follows:
(a) Type 1/4: In the initial stage of bone resorption, the
reduction of the buccal bone is <50% of the expected
implant length, which is usually presented in single
tooth loss

29. (b) Type 2/4: the buccal bone wall absorbed to
form a bladelike alveolar ridge, the height of
alveolar ridge is not reduced while the buccal bone
wall absorbed >50% of the expected implant
length;
(c) Type 3/4: after several years of tooth loss,
bone resorption resulted in a partial reduction in
the height of alveolar ridge, as well as a
reduction in the width
Type 4/4: after several years of tooth loss,
bone resorption achieved full alveolar ridge
reduction on height and width

30. • For types with slight bone defects (type 1/4), traditional GBR technology can be selected
for bone augmentation. For types with massive bone defects (type 4/4), Terheyden et al.
suggested that the bone augmentation method based on onlay bone grafting should be
adopted to meet the needs of severely atrophic alveolar ridge reconstruction.
• And for types with moderate bone defect (type 2/4 and 3/4), GBR with titanium mesh can
be conducted for alveolar ridge reconstruction. And specific procedures of simultaneous or
delayed implantation need to be further subdivided on the basis of these two bone defect
types.

31. • According to the theory of Li et al., types 2/4 and 3/4 can be subclassified into mild and
severe based on the degree of vertical absorption on the buccal or palatal bone wall. Utilizing
the excellent bone augmentation and maintenance ability, for alveolar ridges with light buccal
or palatal plate absorption in vertical direction (mild type 2/4 or 3/4), GBR with titanium
mesh can be applied in simultaneous implantation, as the implant can obtain sufficient initial
stability.
• For alveolar ridges with severe vertical resorption on the buccal or palatal plate (severe
type 2/4 or 3/4), excessive threads would be exposed with simultaneous implantation
procedure, which may lead to failure of implantation owing to subsequent micromotion
of the implant. Hence, it is more recommended to conduct titanium mesh bone
augmentation with delayed implantation

32. COMPLICATIONS OF TITANIUM MESH,
MANAGEMENT, AND PREVENTION
• For complications caused by GBR surgery with titanium mesh, surgical
complications are generally less discussed, and researches pays more
attention to the healing complications.
• During the healing stage, the wound dehiscence and consequent titanium
mesh exposure are the main complications in GBR with titanium mesh.
• The stiffness of titanium mesh and its sharp edges generated in cutting
and bending may cause detrimental stimulation on mucosal flaps, giving
rise to the mucosal rupture and subsequent mesh exposure.
• The incidence of mesh exposure is mostly ~20%–30% and the highest
reported exposure rate is 66%

33. • According to exposure time, the exposure of titanium mesh can be divided
into early exposure and late exposure.
• Exposure occurs within 4 weeks after bone augmentation is considered early
exposure, which is likely to bring about detrimental effects.
• Specifically, it is manifested that an increase in fibrous tissue and a decrease
in bone formation often occur at the bone defect area after early exposure.
• And it may damage the fusion of residual xenograft particles with the
surrounding bone.
• Once early exposure is happened, the titanium mesh should be removed as
soon as possible, and subsequent anti-infection operations should be
conducted.
• The late exposure that occurred 4 weeks after bone augmentation may cause
~15%–25% of the graft resorption in the exposed area, making the exposed
site’s bone volume slightly insufficient.

34. • After conducting anti-infection treatment and trimming sharp or irregular edges of
exposed titanium mesh, the exposed area can heal without removing titanium mesh,
which will not cause subsequent severe complications like infection and bone
grafting failure, and will not influence bone regeneration in the defect area.
• No matter the early or late titanium mesh exposure occurred, it is not easy to cause
consequent infection, which may be related to the smooth surface of titanium mesh,
and the protective effect of the pseudo-periosteum formed between titanium mesh
and the bone graft material.
• This layer of soft tissue protects the graft material from infection, and provides
adequate blood supply, nutrition, and metabolic exchange, preventing the graft
materials from absorption.
• Furthermore, researches indicated that for the periosteal-like tissue is still forming
when the titanium mesh is early exposed, its role in preventing infection has not been
exerted, which is one reason why early exposure needs special attention.

35. • In short, according to Fontana et al.’s summary of the complications during the
use of nonabsorbable membranes in GBR technology, to prevent postoperative
complications, the following should be done: before surgery,
accurate evaluation of the patient’s general condition and local
conditions of the operation area should be done, antibiotics should be
taking preoperatively if necessary, and all sources of infection in the
operation area and its vicinity need to be removed; during surgery, flaps
should be designed to obtain adequate blood supply and facilitate flap
closure, titanium mesh should be immobilize tightly, the buccal
periosteal release and completely tension-free closure must be done, and
deep mattress and single interrupted sutures are recommended; after
surgery, systemic antibiotics and local disinfection care should be
performed, and postoperative precautions should be explained to the
patients clearly.

36. HOW TO SELECT REPLACEMENT
GRAFTS FOR VARIOUS PERIODONTAL
AND IMPLANT INDICATIONS
• The main indications of bone grafting procedures can be divided into both
periodontal and peri-implant disease-related sites and implant site
development applications.
• They include regenerative procedures for destruction caused by
periodontal or peri-implant diseases and bone augmentation procedures
for implant site preparation.
• In addition to defect morphology, selection of bone replacement grafts
should be based on their properties corresponding to indications.

40. GRAFT USED FOR REGENERATION

42. PLATELET-DERIVED GROWTH
FACTOR-BB
• Platelet-derived growth factor-BB (PDGF) is one of most investigated
growth factors in periodontal tissue engineering.
• Since its early introduction in the late 1980s, several animal and clinical
studies have confirmed its role in promoting bone, cementum, and PDL
regeneration.
• Regarding its mechanism of action, it has been shown that PDL and
alveolar bone cells express multiple receptors for PDGF, which enhances
proliferation and chemotaxis of these cells.

43. • In particular, Boyan et al. investigated the effect of the various isoforms of
recombinant human PDGF (AB,AA, and BB) on the mitogenic and
chemotactic responses of PDL cells, showing that PDGF-BB was the most
potent one.
• The rationale of using 𝛽-TCP as a carrier of the rhPDGF-BB∗ is that 𝛽-
TCP particles have a scaffolding role preventing the soft tissue collapse
and providing a matrix for the new bone formation, also facilitating the
stabilization of the blood clot.

44. EVIDENCE/INDICATIONS
• animal studies conducted by Simion and coworkers and Schwarz and colleagues
investigated the potential of PDGF for both vertical bone regeneration and horizontal
bone regeneration, respectively. Both studies have shown greater bone regeneration
when PDGF was used in combination with the grafting material compared to using
the grafting material alone.
• Interestingly, in the above-mentioned studies, Simion et al. tested the effectiveness of
three different treatment groups for vertical bone augmentation: (1) deproteinized
bovine blocks and collagen barrier, (2) deproteinized bovine blocks with rhPDGF-BB,
and (3) deproteinized bovine blocks with rhPDGF-BB and collagen membrane.
• Histological and radiographical analysis demonstrated greater bone formation when
rhPDGF-BB was utilized without collagen membrane, suggesting that membranes
block the migration of bone forming cells from periosteum into the area of interest

46. BONE MORPHOGENIC PROTEINS
(BMP-2)
• Rationale. BMPs are members of the transforming growth factor-beta
(TGF-𝛽) superfamily which have demonstrated high osteoinductive
potential .
• In the periodontics arena, both BMP-2 and BMP-7 stimulate PDL cell
differentiation into osteoblasts and increase expression of mineralized tissue
markers.
• Moreover, BMPs have been demonstrated to downregulate the
mineralization process of cementoblasts.
• Additionally, their employment in the implant field relies on BMPs having
the properties to modulate bone formation, contour, and density through
endochondral formation and bone formation by autoinduction.

47. • Induction and maintenance of bone formation by the TGF- 𝛽 family of
proteins occur in a synergistic and synchronous way with a wide variety of
different proteins acting in the process
Evidence/Indications
• rhBMP-2 (Infuse Bone Graft by Medtronic Inc.) has recently been approved
by the FDA as an alternative to autologous bone grafting for sinus
augmentation and ridge preservation procedures owing to its osteoinductive
potential.
• Clinical and histologic outcomes obtained for sinus augmentation showed
similar pattern to autogenous bone in terms of bone quality and quantity .
• Nonetheless, if rhBMP-2 is grafted in combination with autologous bone it
seems to further increase cell activity, osteoid lines, and vascular supply,
which may lead to more predictable results.

48. • Additionally, rhBMP-2 has been studied for
alveolar ridge augmentation/preservation.
• Although in vivo data is very limited, it was
found to be successful in preventing socket
from collapse by minimizing the horizontal
bone resorption.
• In this study, it was also demonstrated that the
dose-dependent effect of the protein of
1.5mg/mL shows better results than
0.75mg/ml.
• It has also been shown to improve the results
of sinus bone augmentation when used alone.

49. MATERIALS AND METHOD
• The present retrospective study included patients receiving ridge augmentation using
Ti-mesh between March 2009 and July 2013 at a private periodontal practice
(R.A.L.) in Philadelphia, Pennsylvania, for replacement of non restorable or hopeless
maxillary teeth.
• Patients signed a written informed consent for the surgical procedures and data
collection for potential future publication, in accordance with the guidelines of the
World Medical Association Declaration of Helsinki.
• Patients who underwent Ti-mesh ridge augmentation, had an implant placed in the
maxilla, and had complete pre- and postoperative clinical and radiographic data were
included; the exclusion criteria were history of alcoholism or drug abuse, medical
contraindications affecting bone/soft tissue healing, history of cervicofacial
radiation, use of bone sparing medications, poor oral hygiene, poor compliance, and
smoking > 20 cigarettes/day

50. A total of 48 patients (demographic data in Table 1) were identified through the
records. Seven different combinations of biomaterials were used along with Ti-
mesh.
(1) AG/rhPDGF: freeze-dried bone allograft (AG) + recombinant human
platelet-derived growth factor (rh- PDGF);
(2) AG/PRGF: demineralized AG + calcium sulfate powder and autogenous
platelet-rich growth factor (PRGF);
(3) AG/NB: demineralized AG + calcium sulfate powder (no biologics [NB]);
(4) Cellular AG: cellular AG containing a minimum of 250,000 cells/cc;
(5) XG/BMP: deproteinized bovine bone mineral (DBBM) + recombinant
human bone morphogenetic protein-2 (BMP-2);
(6) XG/rhPDGF: DBBM + PDGF; and
(7) XG/rhPRGF: DBBM + PRGF.

51. • All patients received two CBCT scans:
one taken within a month prior to ridge
augmentation, and the other taken prior
to Ti-mesh removal and implant
placement.
• The selection of treatment group was
arbitrarily decided by the same
periodontist (R.A.L.) after acquiring
each patient’s presurgical CBCT image.

52. SURGICAL PROCEDURE
• Briefly, following tooth extraction, the wounds were allowed to heal
spontaneously for 2 to 3 months to have complete soft tissue closure.
• Once the bony defect was confirmed and measured on the presurgical CBCT
scan, the Ti-mesh ridge augmentation procedure was performed.
• Under profound local anesthesia, a full-thickness flap was raised with
vertical incisions at the distal ends of the flap for better visualization and
access.
• After debridement of the granulation tissue, numerous intra marrow
penetrations were made at the buccal surface of the alveolar ridge.

53. • The Ti-mesh was firstly carefully secured to the buccal plate using
stabilizing screws, creating a buccal wall to pack the bone graft, and then
trimmed with surgical scissors to keep a 1.5-mm distance from the adjacent
tooth to prevent postoperative bacterial penetration from the tooth surfaces.
• When needed, additional tenting screws were used to support the mesh.
• One of the seven combinations of biomaterials was placed at the bony
defects, followed by securing the mesh on to the palatal wall to prevent any
micromovement.
• The stability of the mesh was examined carefully.

54. • In three treatment groups (AG/PRGF, AG/NB, and XG/PRGF), a
collagen membrane was used to cover the mesh, while a collagen
dressing tape was used in the other groups.
• When applicable, the collagen membranes were soaked in PRGF, and
the tapes were soaked in rhPDGF, respectively, before being applied to
the augmented sites.
• The surgical site was then sutured to obtain tension-free primary
closure.
• The provisional restorations (either nothing, temporary partial
dentures, flippers, or complete dentures) were delivered, with special
attention to exert no pressure on the graft during the initial healing
period.

55. POSTOPERATIVE HEALING AND IMPLANT
PLACEMENT
• Each patient was followed up at 2 to 3 weeks for suture removal with
plaque control reinforcement and at 4, 8, and 12 weeks postoperatively to
ensure appropriate healing and complete soft tissue coverage over the Ti-
mesh.
• Any early (≤ 6 weeks) or late (> 6 weeks) mesh exposure was recorded.
The patients with mesh exposure would clean the areas with
chlorhexidine and have individualized recall appointments before the
implant placement surgery.
• A second CBCT scan was taken 5 to 6 months postoperatively.

56. • The patient then met their restorative dentist to fabricate a clear
acrylic tooth-borne (when present), digitally designed, anatomically
correct surgical guide template (ACSGT) for prosthetically driven
implant placement.
• The implant surgery took place 7 to 9 months after the Timesh
procedures.
• During surgery, the Ti-mesh was removed, and the implant was
placed. All implants with < 2 mm of bone to the facial of the
osteotomy received contour augmentation using DBBM and a
collagen membrane.

60. CLINICAL INDICES
• The primary outcome is the gain in the ridge width resulting from the Ti-
mesh procedure.
• The initial width was first measured at the widest point (no more apical
than 4 mm from the crest) to the nearest 0.5 mm at the mesiodistal center
of the ridge on the cross-sectional CBCT image, and then confirmed
clinically by the periodontist during surgery.
• The buccolingual width of the ridge at the future implant site was
measured by placing a 15-mm periodontal probe at the crest, measuring to
the nearest 0.5 mm, and documenting it with digital photography.
• The clinical confirmation helped to avoid potential errors from residual
bone grafts (vs healed bone).

61. • Other recorded indices included the change in ridge height, mesh
exposures (none, early, or late), smoking status (yes/no), the
gingival phenotype (thin, medium, or thick; assessed using
visual assessment with the aid of a periodontal probe), implant
location (anterior/ posterior), age (younger adults [< 50 years],
middle-aged [50 to 65 years], or older adults [65+ years]),
gender, the provisional restorations (none, fixed, transitional
partial denture, or complete denture), contour augmentation at
implant placement (yes/no), and treatment groups (seven
biomaterial combinations).

62. STATISTICAL ANALYSIS
• Descriptive statistics for all data were performed. The effects of age,
gender, implant location, gingival phenotype, treatment group,
provisional restorations, smoking, and mesh exposure on the gain in
ridge width were analyzed by fitting a linear regression model.
• For mesh exposure, the final logistic regression model was
determined by stepwise selection. All analyses were completed using
R statistical software (The R Foundation).

63. RESULTS
• A total of 58 mesh procedures covering 91
implant sites were performed in the
maxillae of 48 patients.
• More than half of the mesh procedures
covered a single implant site (32 of 58),
while 20, 5, and 1 mesh procedures
covered 2, 3, and 4 implant sites,
respectively.
• The demographic data of the participants
are summarized.

64. • The clinical outcomes from each treatment group are summarized in Table 2.
• The gross mean horizontal gain was 4.7±1.6 mm, ranging from 4.5 ±1.8 mm in the AG/PDGF
group to 5.7 ± 1.0 mm in the XG/ PRGF group.
• The gross mean vertical Gain from available sites was 2.8 ± 1.7 mm ranging from 1.5 ± 0.7
mm in the XG/BMP group to 3.4 ± 2.9 mm in the AG/rhPDGF group.
• Based on the fitted regression model on the horizontal gain, posterior location (vs anterior)
was significantly associated with more horizontal gain (P = .016; Table 3).

65. • Postoperative mesh exposure occurred after 13 procedures, or 22% of the
time, but no mesh required early removal.
• Late exposure was more frequent than early exposure (62.5% and 37.5%,
respectively).
• Among the sites with exposure, thin phenotype was related to 3 exposures (3
implant sites), medium phenotype was related to 7 exposures (10 implant
sites), and thick phenotype was related to 3 exposures (3 implant sites).
• The logistic regression model indicated that age was positively associated
with mesh exposure: Both the middle aged adults (odds ratio [OR] = 8.59;
95% confidence interval [CI]: 1.04 to 71.09; P = .046) and the older adults
(OR = 16.66; 95% CI: 1.56 to 177.5; P = .02) had significantly higher
chances of mesh exposure than younger adults.

66. • The mean horizontal gain in the exposed sites was slightly less than
that in the unexposed sites (4.4 ± 1.1 mm and 4.8 ± 1.7 mm,
respectively), but the difference was not statistically significant (P >
.05).
• The mean thickness of the pseudo periosteum at the exposed site was
thicker than that at the unexposed sites (1.5 ± 0.6 mm and 1.1 ± 0.8
mm, respectively), but the difference was not statistically significant
(P > .05).
• Contour augmentation during implant placement was performed in
56% of the sites (51 of 91 sites), ranging from 25% in the AG/PRGF
and XG/PRGF groups to 78% in the cellular AG group.
• The differences in the percentages among treatment groups were not
statistically significant. Significantly lower odds of needing
additional contour augmentation were associated with using a
complete denture as the provisional restoration (vs no provisional
restoration; OR = 0.03, P < .001) and posterior location (vs anterior;
OR = 0.21, P = .016) (Table 4).

67. DISCUSSION
• Vertical and horizontal regeneration procedures allow for ideal implant
placement in the reconstruction of deficient alveolar ridges.
• The use of Ti-mesh for implant site development procedures is well
supported in the literature.
• Although Ti-mesh is not cell-occlusive, its biocompatibility and handling
properties that enable it to act as a form-stable scaffold are beneficial in 3D
augmentation procedures.
• The present study found that Ti-mesh with various combinations of
biomaterials produced effective horizontal and vertical bone gain, allowing
prosthetically driven implant placement if the space is well maintained and
stabilized.

68. • Postoperative mesh exposure is the most common complication.
• Early exposure was reportedly more detrimental to bone gain than late
exposure.
• Two systematic reviews reported mean exposure rates of 16.1%and 34.8%
(range: 0% to 80%).
• In a recent systematic review regarding vertical augmentation, other non
resorbable barrier membranes were reported to have a lower complication rate
(6.9%) than Ti-mesh (20%).
• The mesh exposure rate of 22% in the present study was consistent with
systemic reviews: The exposure risk increased as age increased.
• In the younger adults, only 3% (1 of 33) of implant sites had exposure, while
the values were 23% and 36% in the middle-aged and older adults,
respectively.

69. • While most studies did not report an association between age and exposure,
the association between aging and delayed wound healing and increased soft
tissue fragility was biologically plausible.
• Other studies reported male gender and thin gingival biotype as being more
likely to have exposure, while using platelet concentrates over the mesh
reduced the chance of exposure.
• Thick, soft tissue is advantageous because of the high volume of extracellular
matrix collagen to withstand collapse and contraction, as well as the increased
vascularity that boosts wound healing.
• Removable provisional restorations should be passive to reduce the risk of
flap dehiscence from loading over the surgical site.
• Although mesh exposure was related to reduced horizontal bone gain in other
studies, the difference in the present study was not statistically significant.

70. • No mesh was removed early in the present study, though one
systematic review reported the necessity for early removal at 22.8%.
• It is possible that the soft tissue migrates under the exposed mesh,
protecting the graft from infection and limiting the amount of
resorption.
• Consistent with other studies, mesh exposure did not interfere with
successful implant placement in the present study.
• The dimensional changes in bone volume in the present study were
consistent with previous Ti mesh studies.

71. • In a randomized clinical trial of 30 patients,28 effective bone
augmentation was achieved using Ti-mesh with or without platelet-rich
plasma (PRP).
• In the PRP group, the mean horizontal and vertical gains were 4.1 ± 0.6
mm and 3.5 ± 0.7mm,respectively.
• The values in the non-PRP group were 3.7 ± 0.6mm for the width gain
and 3.1 ± 0.8mm for height gain.
• One systemic review reported a mean horizontal augmentation of 4.36
mm (range: 3.75 to 5.65 mm) and a mean vertical augmentation of 4.91
mm (range: 2.56 to 8.6 mm).
• While not all included studies reported implant-related data, the survival
rate was 100% among the 130 analyzed implants.

72. CONCLUSIONS
• With the limitations of this retrospective study, Ti-mesh used with a variety
of biomaterials is an effective technique for implant site development in the
maxilla.
• All cases had sufficient bone gain for implant placement, and the small
differences in horizontal bone gain among different combinations of bone
grafts and biologics were not statistically significant.
• Older adults seemed to have a higher chance of mesh exposure than the
younger adults.
• Patients, especially those undergoing procedures in the anterior region,
should be informed of the possibility of additional contour bone grafting at
the time of implant placement to achieve the desirable bone thickness buccal
to the implants for long term implant success.

73. CRITICAL EVALUATION ?