Evaluation of Zimmer Puros® Allograft vs. Creos™ Allograft for Alveolar Ridge Preservation

Twenty-four consecutive subjects requiring extraction of two non-adjacent molars or premolars
located in the same jaw will be selected from the patient pool of the Center for Advanced
Periodontology at the University of Florida, College of Dentistry.

Preoperative Procedures: At the initial screening, the goals of the study, potential risks
and possible benefits will be explained and each subject will be asked to sign a written
consent statement permitting extraction of the involved teeth and the placement of Puros®
allograft and creos™ allograft for ridge preservation. After which a complete medical and
dental history will be obtained, a pregnancy test will be performed, and establishment of
inclusion and exclusion criteria will be determined. If meeting all study criteria,
examination periapical radiographs will be taken and each subject will receive oral hygiene
instructions, prophylaxis, and full-arch alginate impressions. The study models will also be
used to fabricate occlusal templates to permit reproducible clinical measurements of the
alveolar ridge dimensions of the residual tooth socket.

Surgical Protocol & Treatment Assessment: To help minimize technical variances in the
surgical treatment protocol, the primary investigator will perform baseline and 12-week
re-entry surgeries. Under local anesthesia, full-thickness mucoperiosteal flaps will be
elevated; the selected teeth will be extracted atraumatically, followed by debridement of the
sockets, and collection of all clinical measurements.The following clinical measurements will
be made at the baseline and re-entry surgeries using standard University of North Carolina
(UNC) manual probes (Hu-Friedy, Chicago, IL):

1. Facial/buccal thickness (baseline, only)

2. Distance from the occlusal template to the facial, lingual and crestal bone

3. Socket depth (or template to crest distance at the 90-day re-entry surgery)

4. Osseous dehiscence location and dimension

5. Bone density (on re-entry)

The surgeon will then preserve each site with either Puros® allograft creos™ allograft.
Puros® allograft will be placed into half of the extraction sockets to the level of the
osseous crest. A bovine pericardium membrane (CopiOs ®Pericardium) will be then placed to
cover the bone graft material. Primary closure will be achieved in all cases. The site will
be sutured with 4.0 PTFE sutures. The other extraction sites will receive the same treatment
but with creos™ allograft. Participants will be prescribed a 10 day regimen of Ibuprofen
(2.4g/day) and antibiotics (amoxicillin (1.5g/day) or clindamycin (0.6g/day)) unless other
allergies are present. Subjects will be instructed to change their diet to semi-liquid for 48
hours, followed by soft foods for the first 2-weeks. Subjects will also be instructed to
begin rinsing with warm water, as needed, and to resume their normal oral hygiene routine the
day after surgery in all areas except the surgical site.

At 2-week post-surgery, the extraction sites will be inspected and gently cleaned with
saline-soaked gauze, health histories will be reviewed, oral hygiene instructions will be
repeated, photographs will be taken; and a plaque score will be recorded. Cone beam CT images
will be performed 2 weeks and 12 weeks post-operative. All imaging will be done using the
Kodak limited view CBCT to minimize the subjects' exposure to radiation.

Soft tissue healing will be assessed at 2, 8 and 12 weeks with a wound-healing index (WHI)
according to the following scheme: score "1" for uneventful wound healing with no gingival
edema, erythema, suppuration, discomfort or graft exposure; score "2" for uneventful wound
healing with slight gingival edema, erythema, or discomfort, but minimal loss of graft and no
suppuration; score "3" for poor wound healing with significant gingival edema, erythema,
discomfort, loss of graft or any suppuration.

Re-entry surgery will be performed at 12 weeks, and all clinical measurements will be
repeated. Crestal flapless soft tissue and bone core biopsies approximately 2.7 x 10 mm in
size will be removed with a 3.2 mm trephine drill from the area corresponding to the center
of the previous extraction from the crest of the ridge using the occlusal template as a
guide.

The cores will be placed in bottles of 10% neutral buffered formalin (NBF) for fixation, and
then labeled with a 5-digit number in order to permit masked histomorphometric analysis.
Analysis will be performed in the outer aspect of the bone cores, which correspond to the
bone surface that will contact the dental implants at the time of placement. Zimmer TSTV
implants will be placed at the same time the second re-entry procedure is done. All implants
will be placed according to the manufacturer's specifications. Restorative treatment will be
initiated 90 days after implant placement.

Inclusion Criteria:

- Systemically healthy subjects with two non-adjacent molar or premolar teeth located in
the same jaw that require extraction and socket augmentation for implant site
development (treatment sites may be located in either the mandibular or maxillary jaw)

- Residual extraction sockets must have <70% bone loss in all dimensions (3 or 4-walled
bony defects)

- Nonsmokers (individuals who quit smoking at least 6 months prior to the study will be
allowed to participate)

- Subjects willing and able to comply with all study-related procedures including
maintenance of good oral hygiene and compliance with re-evaluation appointments

- Subjects who read, understand and are willing to sign an informed consent statement.

Exclusion Criteria:

- Inadequate zone of keratinized gingiva (KG) or alveolar mucosa to obtain primary wound
closure of the surgical site

- Presence of acute infections at the time of tooth extraction

- Clinically significant or unstable (as defined by the investigators) systemic diseases
affecting bone or soft tissue growth; or other renal, hepatic, cardiac, endocrine,
hematologic, autoimmune or acute infectious diseases that makes interpretation of the
data more difficult

- History of head & neck radiation therapy

- Subjects taking steroids, tetracycline or tetracycline analogs, bone therapeutic
levels of fluorides, biphosphonates, medications affecting bone turnover, antibiotics
for >7 days or any investigational drug

- Patients who are or become pregnant during the length of the study.