Alveolar ridge preservation with a xenograft Bio-Oss Collagen) and a collagen matrix (Mucograft Seal) or a free connective tissue graft versus spontaneous healing: a 1-year prospective randomized clinical study

Replacement of a single tooth in the esthetic zone is a demanding procedure.
For optimal esthetic results, no deficiency in both bone and soft tissue is
acceptable. Immediately after tooth extraction, the alveolar ridge undergoes
horizontal and vertical bone loss (Lang et al., 2012). This negatively
influences the soft tissue contours, and thus esthetic outcome. Although
immediate placement of an implant after extraction leads to acceptable esthetic
results, there is an increased risk of mucosal recession due to the lack of
adequate soft tissue (Lang et al., 2012; Chen et al., 2014). Early implant
placement, 4 to 8 weeks after extraction, may offer advantages in terms of soft
and hard tissue preservation (Sanz et al., 2012; Buser et al., 2014). The main
goals when treating the extraction socket in the esthetic zone is to preserve
as much as possible existing soft and hard tissue volume as possible for future
implant placement (Fickl et al., 2012). Landsberg described a modified ridge
preservation technique called *socket seal surgery* where flap elevation is
avoided and it combines both bone and soft tissue grafting prior to implant
placement. Closing the extraction site from the oral cavity using a thick
epithelized palatal graft enables optimal ridge preservation immediately after
tooth extraction (Landberg et al., 1994). Jung showed that the application of a
slowly resorbing biomaterial (BioOss Collagen®, Geistlich) into an extraction
socket, covered with an autogenous palatal soft tissue punch graft resulted in
a high predictability and reliability for a good esthetic result for future
(early) implant placement (Jung et al., 2004). The primary intention for the
placement of the biomaterial is not to enhance bone formation, but to support
the buccal contour of the alveolar ridge and stabilize the blood clot. Although
a soft tissue graft is a relatively easy procedure, patient morbidity is often
associated with the second surgical site (Griffin et al., 2006). An artificial
socket seal might prevent donor morbidity associated with soft tissue grafts.
Although there seems to be no difference in the long term change of the buccal
soft tissue contour between an autogenous soft tissue punch graft and a
collagen matrix (Schneider 2014), there is a lack in data concerning the
difference in esthetic outcome between these two methods in early implant
placement.

To evaluate clinical and esthetic outcomes and patient satisfaction following
single-tooth replacement in the anterior maxilla in patients treated with a
collagen matrix (Geistlich Mucograft® Seal) and a free connective tissue graft
versus spontaneous healing.

A prospective randomized clinical study with 1-year follow-up.

In the current prospective randomized clinical study, patients are assigned to
one of three socket seal techniques:

A) Placement of a bone substitute material (demineralized bovine bone mineral
with 10% collagen; Bio-Oss Collagen®, Geistlich) covered with a collagen matrix
(Geistlich Mucograft® Seal).

B) Placement of a bone substitute material (demineralized bovine bone mineral
with 10% collagen; Bio-Oss Collagen®, Geistlich) covered with a punch biopsy of
the palate.

C) Spontaneous healing (control group).

The measurements performed in this research are analyses of the peri-implant
soft tissue and radiological analyses. Participation in this research is not
dangerous and the patients are not at risk. The radiographs (before and after
placing the implants) are taken anyway whether or not the patient is
participating in this research. Radiological follow-up is not dangerous; the
health of the patients is not at risk. Because the treatments are already
performed for many years we expect no unknown or known incidences. In case of
pregnancy the treatment is not performed. In case the patient wants to withdraw
from this research this does not have any consequence. The treatment will be
identical. However, the so far collected measurements data cannot be used
anymore for this research.