A clinical, prospective feasibility study to assess the effectiveness and safety of micro-structured TCP granules as a bone augmentation material in sinus floor elevation procedures.

The placement of dental implants requires the presence of adequate bone. In
patients with inadequate bone volume, additional surgical techniques may be
needed to achieve acceptable treatment results. In the case of extensive
alveolar defects or in relation to expanded maxillary sinuses, onlay or inlay
grafting procedures have been advised. To create enough bone quantity and
quality for the insertion of oral implants in the maxilla, so-called sinus
floor elevations are performed. In this procedure, a small window is created in
the lateral wall of the maxilla, the sinus epithelium is elevated and the
created space is filled with a grafting material. The iliac crest is the most
common donor site for obtaining autologous bone grafts. However, the surgical
removal of bone from the iliac crest requires an additional surgical procedure
with a distinct set of disadvantages (i.e. possibility of infection, donor site
pain, etc). Calcium phosphate (CaP) implant materials are widely used as an
alternative to autologous bone transplantation. In this study micro-structured
TCP granules will be used as a bone graft. These granules can be shaped exactly
to the defect. A solid and mechanically strong bone filling construct by
degradation and replacement of the biomaterial by the patients own surrounding
bone during the time after augmentation will develop.

The primary objective is to determine whether micro-structured TCP granules
provides sufficient bone volume as basis to insert endosseous dental implants
in a two staged sinus floor elevation technique by benefiting from the clinical
handling properties of this material. An additional primary objective is to
quantify the biodegradability of the micro-structured TCP granules. Secondary
objective is to investigate the clinical performance, pain, health related
quality of life, economical evaluation and the safety profile of
micro-structured TCP granules.

Clinical, prospective, single center feasibility study

Patients fulfilling all in- and exclusion criteria will be requested for
informed consent and scheduled for sinus floor elevation surgery. At surgery
patients will undergo sinus augmentation with micro-structured TCP granules,
postsurgical visits will be scheduled as in regular therapy to check the course
of healing. Secondly after a healing period of the sinus of 5 months insertion
of the endosseous implant will take place and a biopsy will be obtained.

Sinus elevation procedures with bone of the crista iliaca region, cause a
secondary operation site and result in donor site morbidity e.g. pain, gait
disturbances, deviation in form, meralgia paresthetica, or herniation of
intestine. Moreover, the available bone volume in the crista iliaca is limited
and the grafting procedures result in prolonged operation time. Grafting
procedures of the iliac crest always are performed under general anesthesia.
The method of applying micro-structured TCP granules can be performed under
local anesthesia because of the absent donor site.

Micro-structured TCP granules have already been tested in vitro and in vivo. No
adverse reactions to the biomaterial have been observed. The potential risks
related to this study are associated with normal sinus augmentation surgery
such as pain, infection and loss of the grafting material. At the start of the
study, micro-structured TCP granules will bear a CE mark.

It was decided to include patients with the presence of a residual alveolar
ridge height between 3 and 8 mm. A minimal amount of original bone height is
needed to allow ingrowth of new bone into the micro-structured TCP granules.

Visits and radiographic evaluation will be scheduled according to regular
treatment procedures. Five months after augmentation a biopsy will be obtained
during implant insertion. During visits 1 and 3 up to 7 SF36 questionnaire and
VAS pain score will be performed.