A clinical prospective feasibility study to address the effectiveness and safety of calciumphosphate/poly(lactic-co-glycolic-acid) for bone augmentation in maxillary sinus floor elevation surgery.

Various bone regenerative treatments are clinically applied to obtain
sufficient bone volume for dental implant placement. Autografting, in which
autologous bone is used to regenerate bone defects, is still considered the
gold standard. The major disadvantage of this type of treatment is the need of
an extra surgical site to harvest donor bone, leading to an extra burden for
the patient, donor site morbidity and an increased infection risk. An
alternative treatment modality is the use of an allograft, in which processed
cadaver bone is transplanted into the patient. Disadvantages of this type of
treatment involve graft-versus-host reaction and possible transmission of
diseases.
Synthetic bone substitutes are thoroughly explored in literature due to the
abovementioned disadvantages related to the use of autologous bone and
allografting. Synthetic calcium phosphate (CaP) ceramics are the most widely
used biomaterials for bone regenerative treatments in the field of dentistry,
trauma surgery, plastic and reconstructive surgery and orthopedics. Their
biological performance is characterized by bioactivity and osteoconductive
properties. A major drawback of CaP ceramics however, is their generally poor
degradability.
Previous research provided an injectable, well-degradable porous CaP cement
(CPC), successfully developed via inclusion of poly(D,L-lactic-co-glycolic
acid) (PLGA) particles. The PLGA particles in CPC degrade in a relatively short
time period thereby inducing porosity in CPC which increases the surface area
available to interact with body fluids (Lanao et al. 2011, Lopez-Heredia et al.
2012). This process enables faster degradation of CPC, leading to the
possibility of new bone formation.
An example for the importance of bone regeneration in the craniomaxillofacial
region is the placement of dental implants, which requires the presence of
adequate bone volume. In patients with inadequate bone volume, additional
surgical techniques may be needed to achieve acceptable treatment results. In
the maxilla, typically a lack of bone volume is present in the posterior region
due to the presence of the often pneumatized maxillary sinus. To create enough
bone quantity for the insertion of dental implants in this region, a so-called
sinus floor elevation procedure can be performed. In this procedure, a small
window is created in the lateral wall of the maxillary sinus, the sinus
epithelium is elevated and the created space is filled with a grafting
material.
In this study the effectiveness, in terms of new bone formation and implant
survival, and safety of injectable CPC combined with PLGA (CPC-PLGA) will be
addressed using the technique of sinus floor elevation surgery.

The primary objective is to determine the feasibility of applying CPC-PLGA in
sinus floor elevation surgery in terms of bone formation and implant survival.
The secondary objective is to investigate pain, health-related quality of life
and the safety profile of CPC-PLGA.

Clinical prospective feasibility study.

Patients fulfilling all inclusion criteria will be requested for informed
consent and scheduled for sinus floor elevation surgery with CPC-PLGA. Surgery
is performed under local anesthesia. Prophylactic antibiotics will be
administered 1 hour prior to the surgery and on a daily basis for seven days
post-operatively. Post-surgical visits will be scheduled as in regular therapy
to check the course of healing. After a healing period of 5 months, insertion
of a dental implant will take place and a biopsy will be obtained via a
trephine bur at the exact implant site.

Sinus floor elevation procedures with autologous bone are most often performed
with crista iliaca bone. Grafting procedures with bone harvested from the iliac
crest cause a secondary surgical site leading to donor site morbidity and are
always performed under general anesthesia. Further, this procedure increases
the risk of gait disturbances, deviation in form, meralgia paresthetica
(neuropraxia N. cutaneus femoralis lateralis), or herniation of intestines.
Moreover, the available bone volume in the crista iliaca is limited and the
grafting procedures result in prolonged operation time. The method of applying
CPC-PLGA can be performed under local anesthesia because of the absent donor
site, thereby significantly reducing the abovementioned drawbacks and costs.
CPC-PLGA has already extensively been tested in vitro and in vivo. No adverse
biological reactions to the biomaterial have been observed. The potential risks
related to this study are associated with normal sinus floor elevation surgery,
such as pain, infection and loss of the grafting material.