Socket Preservation Procedure Studying Soft and Hard Tissue Outcomes

The effect of different surgical techniques for socket preservation on soft tissue parameters has seldom been investigated. The aim of this study was to evaluate One with a cross-linked membrane used in secondary intention healing and the other with a non-cross-linked membrane used in primary intentional healing. Thirty subjects requiring tooth extraction were randomly allocated to either control group C (allograft covered with a non-cross-linked collagen membrane with primary closure) or experimental group E (allograft covered with cross-linked collagen membrane left exposed). Sites were surgically re-entered at 6-months. Soft and hard tissue measurements, cone beam computed tomography (CBCT) and cast measurements were taken at baseline \& 6-months.

• Socket preservation control (Procedure): After a tooth was extracted, the adjacent gum tissue was fully reflected, bone graft (FDBA) and non-cross-linked barrier membrane (Bio-Gide) were applied to the defect. The site was stabilized with sutures. Patients were followed for 6 months post operatively.
• Socket preservation experimental (Procedure): After a tooth was extracted, the adjacent gum tissue was minimally reflected, bone graft (FDBA) and cross-linked barrier membrane (OssixPlus) were applied to the defect. The site was stabilized with sutures. Patients were followed for 6 months post operatively.

Primary outcomes

• Keratinized tissue width [6 months]: Keratinized gingival tissue width measured from the free gingival margin to the muco-gingival junction.

Secondary outcomes

• Keratinized tissue thickness [6 months]: Keratinized gingival tissue thickness measured with a needle and stopper 3mm from the free gingival margin.
• Vestibular Depth [6 months]: The distance from the free gingival margin to the apical extent of the vestibule measured with a probe.
• CEJ-FGM [6 months]: The distance from the tooth's cervical enamel junction (CEJ) to the free gingival margin (FGM) was taken with a probe.
• Ridge Width [6 months]: After the gum tissue is reflected, the width of the ridge 6mm from the crest was measured with a caliper.
• CEJ- Buccal crest [6 months]: The distance from the tooth's cervical enamel junction and the top of the buccal bone crest was taken with a probe.
• CBCT bone height [6 months]: CBCT scans were taken and the alveolar ridge height was then measured.
• CBCT bone width [6 months]: CBCT scans were taken and the alveolar ridge width was then measured.
• Cast ridge width [6 months]: Dental impressions were taken and stone casts obtained from them.The ridge width was then measured with calipers.
• Cast ridge volume [6 months]: Dental impressions were taken and stone casts obtained from them.The ridge volume was measured using an optical scanner.

Sex: All, ages: 20 Years to 80 Years, accepts healthy volunteers

Inclusion Criteria:

1. between 20-80 years of age
2. healthy with no conditions that could alter wound healing
3. requiring the extraction of a non-molar tooth with two neighboring teeth on either side and intact bony walls
4. a tooth requiring extraction that is treatment planned for implant placement
5. willing to participate in the study and sign the informed consent
6. willing to receive clinical exams, radiographs, surgery, two and six week post-operative exams and six month re-entry exam.

Exclusion Criteria:

1. systemic conditions which could alter wound healing
2. tooth anatomy requiring aggressive bone removal or greater flap reflection for extraction
3. severe local infection at extraction site
4. a tooth exhibiting severe resorption of buccal or lingual plates
5. absence of keratinized tissue buccal to the tooth to be extracted
6. severely reduced vestibular depth (≤ 3.0 mm) at the tooth to be extracted.

• Informed Consent Form (PDF, 2016-07-22)
• Study Protocol and Statistical Analysis Plan (PDF, 2016-05-06)

• Eli Machtei, DMD, Principal investigator, Harvard School of Dental Med.