Journal of Oral Biology
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Case Report
Horizontal Ridge Augmentation Using PDLLA Fixing Screw in Combination with a Block Graft in a Tunnel Technique to Replace Amaxillary Anterior Missing Tooth - A Case Report
Alghamdi R, Guei-hua GH, Sawada M, Kakumoto T and Fernández-Guallart I, Cheng Yu PY*
Department of Periodontology and Implant Dentistry, New York University, USA
*Address for Correspondence: Cheng Yu PY, Department of Periodontology and Implant Dentistry, New York University, Clinic 5W, 345 E 24th St, New York, NY 10010, New York, USA, Tel: +1-3472792958; E-mail: ycy233@nyu.edu
Submission: 19 December 2019
Accepted: 22 January 2020
Published: 28 January 2020
Copyright: © 2019 Cheng Yu PY, et al. This is an open access article
distributed under the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.
Abstract
An important aspect of the success criteria for dental implants in the
maxillary anterior area involves the establishment of soft tissue contours with
an intact inter-implant papilla and a gingival outline that is harmonious with
the gingival levels of the adjacent healthy dentition. Recently, the tunnel
technique was introduced to maintain the integrity of the soft tissue as an
alternative approach for horizontal augmentation, ideally used in sites with
2-wall defects or a prominent C-shaped curvature of the alveolar ridge.
The purpose of the present case report is to describe step by step a ridge
augmentation procedure utilizing the tunnel technique in combination with
an allograft block graft for horizontal ridge augmentation, performed in
anterior maxilla.
Introduction
Th e anterior maxilla has traditionally been seen as a challenge
when it comes to successfully placing dental implants. An important
aspect of the success criteria for dental implants in the maxillary
Anterior area involves the establishment of soft tissue contours
with an intact inter-implant papilla and a gingival outline that is
harmonious with the gingival levels of the adjacent healthy dentition
[1,2]. Th is is especially true in patients with a high smile line. Th e
clinician must also be aware of the patient’s desires and expectations
regarding esthetics when restoring an implant to provide the best
treatment options.
Following an uncomplicated extraction, the width of the alveolar
ridge has shown to be reduced by approximately 50% aft er 12 months,
with two thirds of this reduction occurring in the fi rst 3 months [3].
Restoring horizontal hard tissue to the alveolar ridge for implantation
is one of the most common challenges for correct 3-dimensional
implant placement. Various techniques have been suggested in the
literature to increase atrophic horizontal bone [4-11]. Successful
bone graft ing is a multifactorial process that requires the following
osteogenic cells including osteoblasts and/or mesenchymal stem cells
which originate from the existing bone [5-7], enough blood supply
from the adjacent periosteum or cancellous bone to nourish the graft ,
an appropriate volume of resorbable graft that does not exceed the diff usion distance of oxygen and nutrients to the graft site [8-10],
tension-free primary closure of the incision that protects the graft
from the oral environment, and a suffi cient quantity of cancellous
bone at the recipient site providing stability, nourishment, and cells
to transform the graft into vital bone [10]. Both non-resorbable and
bioresorbable barrier membranes have been used to contain the
graft materials and allow osteoblast cells to repopulate the defect and
prevent ingrowth or migration of undesired soft tissue [11].
However, the use of membrane barriers may have some potential
complications. Th e most commonly encountered complication is
wound dehiscence and early membrane exposure, which can lead to
bacterial colonization and infection, necessitating early removal of
the membrane and materials. A percentage between 22% and 32% of
early membrane exposure has been reported for collagen membrane
by several authors [12-15], and it has been shown that bone gain is
considerably decreased when it happens in an early stage [16,17].
Recently, the tunnel technique was introduced to prevent these
undesirable exposures by maintaining the integrity of the soft tissue
and in consequence, it’s blood supply. It is an alternative approach
for horizontal augmentation, ideally used in sites with 2-wall defects
or a prominent C-shaped curvature of the alveolar ridge [18].
Th e purpose of the present case report is to describe step by step
a ridge augmentation procedure utilizing the Tunnel technique
in combination with an allograft block graft for horizontal ridge
augmentation, performed in anterior maxilla.
Report of a Case
A 26 years-old African-American male patient presented to the
New York University College of Dentistry Ashman Department
of Periodontology and Implant Dentistry with a chief complaint
of wanting to replace a missing maxillary anterior tooth. Th e right
maxillary central incisor was avulsed following a traumatic injury
in a football game at the age of 22. He had undergone orthodontic
treatment for two years in a private clinic and was referred to implant
clinic for the evaluation of an Implant-supported restoration to
replace this tooth. Th e patient did not have any medical conditions
and was not taking any medications.
Clinical intra-oral pictures revealed a severely horizontally
atrophic ridge in its labial-palatal dimension, which presented limited
space for placement of a standard diameter implant (Figure 1 and 2).
A Cone Beam Computed Tomographic (CBCT) scan was taken and
evaluated, showing a 2 mm ridge width 2 mm apical to the crest of
bone (Figure 3).
Figure 1: Pre-operative clinical frontal view showing a severely atrophic
anterior maxillary edentulous ridge.
Figure 2: Pre-operative clinical occlusal view a severely atrophic anterior
maxillary edentulous ridge.
Th e treatment options for replacing the missing tooth were
discussed with the patient, including a removable partial denture, a
fi xed partial denture, and an Implant-supported crown. Th e patient
opted for the implant option, being aware that bone augmentation
would be necessary to complete the implant supported restoration.
He agreed to the procedure and the subsequent placement of an
implant supported crown.
Ridge augmentation procedure:
Th e patient took 2 grams of oral amoxicillin 1 hour prior to
surgery and was instructed to continue amoxicillin 500mg tablets
three times a day for 7 days post-surgery. Anesthesia was achieved
by local infi ltration of Xylocaine (Lidocaine HCl, Henry Schein,
CA) 2% containing epinephrine at a concentration of 1:100,000.
Two vertical incisions were made on labial side mesial and distal of
area #8the maxillary right central incisor, from the interproximal
mucogingival junction and apically, followed by periosteum elevation
to create the subperiosteal tunnel (Figure 4). Decortication was done over the recipient site, and a hole was made for the Poly-D-L-Lactic
Acid (PLDLLA) pin (SonicPin) insertion (Figure 5). Th e allograft Th e
patient was prescribed took 2 grams of oral amoxicillin 1 hour prior
to surgery and was instructed to continue amoxicillin 500 mg tablets
three times a day for 7 days post-surgery. Anesthesia was achieved
by lLocal infi ltration anesthesia of Xylocaine (Lidocaine HCl,
Henry Schein, CA) 2% containing epinephrine at a concentration
of 1:100,000 was used. Two vertical incisions were made on labial
side mesial and distal of area #8the maxillary right central incisorf, r
from the interproximal mucogingival junction and apically, followed
by periosteum elevation to create the subperiosteal tunnel (Figure 4). Decortications was done over the recipient site, and a hole was
made for the Poly-D-L-Lactic Acid (PLDLLA) pin (SonicPin)
insertion (Figure 5). Th e allograft block (Zimmer-Biomet, Florida)
was adjusted using a high speed diamond bur to the ideal shape and
volume (Figure 6). Th e block was inserted underneath the mucosa
and adapted to the recipient site (Figure 7). A 2.1x13 mm SonicPin
was used to fi x the block to the bone (Figure 8). Aft er fi xation was
completed, the SonicPin went through the middle of the block
into the labial bone (Figure 9). Tension-free soft tissue closure was
achieved using 4/0 Chromic Gut resorbable material (635-CG, Henry
Schein, CA) (Figure 10).Implant placement procedure:
Aft er 4 months of healing, a new Cone Beam Computed Tomography (CBCT) scan was taken prior to implant placement,
presenting an increase of 6mm in width of the alveolar ridge (Figures 11 and 12). A full thickness fl ap was refl ected, and a bone level implant
(4.1x12 mm; Straumann, Switzerland) was installed into the prepared
site with an insertion torque of 35 N/cm (Figure 13). Following cover
screw placement, the surgical site was sutured with 4-0 Chromic Gut
and allowed to heal.
Figure 3: Pre-operative CBCT scan image of Anterior maxillary edentulous
area. Note the 2mm thick alveolar ridge.
Figure 4: Two vertical incisions were made, followed by the periosteum
elevation to create the subperiosteal tunnel.
Figure 5: Decortication was done over the recipient site, and a hole was
made for the SonicPin insertion.
Figure 6: The allograft block was adjusted using a high speed diamond bur
to the ideal shape and volume.
Restorative procedure:
Th e implant was allowed to integrate for 4 months. Th e second
stage procedure was done to expose the implant platform, and a
chairside-made, screw-retained acrylic provisional crown was placed
(Figures 14 and 15). Th ree weeks later, when soft tissue shaping was
achieved with the provisional restoration, a customized impression
coping was fabricated according to the emergence profi le of the
provisional crown, and a fi nal implant impression was made. Aft er
6 months, a screw-retained porcelain fused to metal crown was
delivered and torqued to 35 N/cm. No abnormality of the implant
area was noted, and the patient was satisfi ed with the result and did
not report any pain or inconvenience (Figures 16 and 17).Maintenance procedure:
Aft er the initial surgery treatment, the patient was followed
up every 6 months for 3 years on appropriate oral hygiene and
maintenance programs, which are crucial for long-term success.Discussion
Th e availability of adequate bone volume for dental implant
placement is oft en diminished by trauma, pathology, periodontal
disease, and tooth loss. Bone resorption in the maxillary ridge
frequently results in a knife-edged deformity, which complicates
implant placement and stabilization. Th e end goal of implant therapy
is to provide a functional restoration that is in harmony with the
adjacent dentition [19]. Th ese horizontal hard tissue defects are the
most common challenge encountered. Many options for management
of these defects exist, assuming that an implant of appropriate
diameter is to be placed and graft ing at the time of implant placement
is not an option. One of the most common methods for treating
horizontal bone defi ciency is the use of barrier membranes for guided
bone regeneration. Many variations of this approach have proved to
be successful, but are not exempt of complications, being the most
common of them wound dehiscence and early membrane exposure,
which can compromise the fi nal amount of gained bone. Th e tunnel
technique shows less wound dehiscence or membrane exposure
as well as fewer required courses of antibiotics and postoperative
visits. In fact, it has been reported by some authors as a more cost
eff ective and time-effi cient option with similar success and fewer
complications, thus being considered as minimally invasive [20-22].
It is been shown to provide a conservative approach to accessing oral
bone graft ing sites while minimally compromising the blood supply and reducing trauma to the soft tissue, allowing to maintain primary
closure uneventfully, which is vital for any graft ing procedure. In
contrast to the open-fl ap techniques, the tunnel technique allows
better soft tissue closure, and thus helps in reducing the chances of soft
tissue dehiscence, as well as secures bone graft healing. In tunneling
techniques, the periosteum is detached during the preparation, but
stretched without horizontally cutting it, and thus , the bone graft
remains directly in contact with it [23].
Autogenous bone harvested from either extraoral or intraoral sites
was reported as a gold standard in post-trauma cases [24]. Th e graft
must possess strength and rigidity to allow its fi xation in the recipient
site and 3-dimensional stability to withstand muscular forces.
Consequently, an autogenous block graft is oft en recommended in
the post-traumatic anterior maxilla. Recent studies suggest that a
block allograft in conjunction with a resorbable membrane may be an
acceptable alternative to the autogenous block graft in the treatment
of compromised alveolar ridges. Th e incentive for using an allograft
block in post-traumatic cases in young patients is to avoid donorsite
morbidity. Functional and esthetic post-traumatic demands are
provided by the use of cancellous allograft blocks without donor site
morbidity and discomfort to the patient [25].
Figure 9: After fi xation was completed, the SonicPin went through the middle
of the block into the labial bone.
Th e contouring of the block by the surgeon demands considerable
surgical time and it’s considered one of the major requirements for the success of the tunnel technique in graft s [26], since a good adjustment
of the graft into the recipient bed promotes greater stability to it.
Currently, most of the appositional bone block graft s are stabilized to
the receptor through rigid fi xation with medical grade stainless steel
screws. However, the use of this type of screw requires its removal in
a second surgical procedure before the placement of dental implants,
causing a more morbid and time-consuming experience for the
patient due to this additional surgery. Another drawback associated
with the removal of the screws is that it takes a long releasing incision
to access them, oft en in a high-demand aesthetic region [27]. During this procedure, it is necessary to detach the periosteum covering
the bone graft , which preservation is believed to be a key factor
contributing to the successful integration of the graft to the receptor
bed. Moreover, despite the fact that fi xing screws are generally made of
a poorer titanium alloy, it is possible that these screws osseaintegrate
to the graft , which can hinder their removal and even cause damages
that compromise the overall outcome of the procedure [28]. PDLLA
screws do not interfere in the incorporation of the graft s and on bone
viability and/or quality; also they do not need to be removed. Th e
PDLLA screws, whose contours are reported to be clearly visible in
all biopsies, are encapsulated by a thin and immature fi brous tissue
capsule containing many giant cells in direct contact with the PDLLA
material as well as infi ltrating in areas with fragmented PDLLA.
PDLLA particles are observed within the giant cells. Furthermore, the
adaptation of the biodegradable screws for fi xation of the bone graft s
results as uncomplicated as with metal screws, with the advantage
that they do not need to be removed, thus avoiding a second surgery
to do so and creating less morbidity to the patient. A part from that,
the fact that they remain partially in the bone and thus connecting it
to the block graft prevents separation of it in the moment of implant
osteotomy, as can happen in conventional cases aft er the titanium
screws are removed, due to incomplete graft incorporation in the
recipient site and drilling vibration. In the present study, only one
PDLLA fi xing screw was placed instead of two conventional metal
screws, there was no second surgery to remove it, and neither an
undesirable separation of the graft at the time of implant placement.
Th e tunnel technique and PDLLA allowed the surgery to be performed in a shorter time and with less complications.
Conclusion
Utilizing implant-supported fi xed prosthesis to solve singlemissing
edentulous ridge in the anterior maxilla area has been
achieved predictably. However, an ideal aesthetic result may be
hard to achieve given certain initial conditions. Th e result of this
case report clearly demonstrates how to successfully manage singletooth
replacement in a considerable complex initial situation with
step by step surgical and prosthetic procedure. Th e tunnel technique
for bone augmentation in combination with the use of an allograft
block graft stabilized with biodegradable PDLLA fi xing screws is a
simple and easy to perform technique, which is completed with less
surgical time, less appointments and less morbidity to the patient,
and has presented a high predictable results with high success rate in
the present case. To validate this results, multi-centered randomized
controlled studies about these techniques should be performed.