Khalid Al-Hezaimi Ivan Rudek Khalid S. Al-Hamdan Fawad Javed Nasser Nooh Hom-Lay Wang Efficacy of using a dual layer of membrane (dPTFE placed over collagen) for ridge preservation in fresh extraction sites: a micro-computed tomographic study in dogs Authors’ affiliations: Khalid Al-Hezaimi, Khalid S. Al-Hamdan, Fawad Javed, Hom-Lay Wang, Engineer Abdullah Bugshan Research Chair for Growth Factors and Bone Regeneration, 3D Imaging and Biomechanical Lab, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia Khalid Al-Hezaimi, Khalid S. Al-Hamdan, Department of Periodontics and Community Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia Nasser Nooh, Department of Oral and Maxillofacial Surgery, King Saud University, Riyadh, Saudi Arabia Ivan Rudek, School of Dentistry, University of Michigan, Ann Arbor, MI, USA Hom-Lay Wang, Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, USA Corresponding author: Dr Khalid Al-Hezaimi Engineer Abdullah Bugshan Research Chair for Growth Factors and Bone Regeneration 3D Imaging and Biomechanical Lab, College of Applied Medical Sciences, King Saud University Riyadh, Saudi Arabia Tel.: +966 50 230 3000 Fax: +966 1 46 78639 e-mail: hezaimik16@gmail.com Key words: collagen membrane, high-density polytetrafluoroethylene membrane, micro-com- puted tomography, ridge preservation Abstract Objective: To assess if overbuilding the buccal plate or using a dual-layer socket grafting technique prevents alveolar bone resorption and enhances final ridge width, height, and volume after tooth loss in an animal model. Material and methods: In eight beagle dogs bilateral second (P2)-, third (P3)-, and fourth (P4) premolars were endodontically treated. All bilateral mandibular first premolars and distal roots of P2, P3, and P4 were hemisectioned and atraumatically extracted. Animals were randomly divided into four groups: (i) Control–Socket alone, (ii) Particulate allograft in the alveolum, socket covered with high-density polytetrafluoroethylene (dPTFE) membrane and sutured over the alveolum, (iii) Particulate allograft in the alveolum and overbuilding the buccal plate, socket covered with dPTFE membrane and sutured over the alveolum, (iv) Particulate allograft in the alveolum and covered with dual layer (dPTFE placed over collagen membrane), and sutured over the alveolum. After 16 weeks, the animals were sacrificed. Mandibular blocks of the jaws were assessed for bone volume (BV), vertical bone height (VBH), alveolar ridge thickness, and bone mineral density (BMD) using micro-computed tomography. Results: The BV in groups 1, 2, 3, and 4 was 169.5, 207.57, 242.4, and 306.1 mm 3 , respectively. The VBH in groups 1, 2, 3, and 4 was 4.2, 6.4, 6.2, and 7.3 mm, respectively. Ridge widths in groups 1, 2, 3, and 4 were 5.45 ± 0.75, 5.91 ± 0.86, 6.05 ± 0.63, and 6.28 ± 1.01 mm, respectively. There was no significant difference in BMD between the groups. Conclusions: The RP using a dual layer of membrane following tooth extraction results in more BV, VBH, and alveolar ridge width as compared to when a single layer of membrane is used. Tooth extraction is a traumatic procedure that jeopardizes alveolar bone and surrounding soft tissues (Amler 1969; Arau ´ jo & Lindhe 2005). During the healing process, the extraction socket is initially filled with blood and by the first-week of extraction, is replaced by granula- tion tissue (Amler 1969). By the 14th day of extraction, granulation tissue is replaced by connective tissue and osteoid bone starts appearing in the base of the socket. The socket gets completely filled with woven (bundle) bone by the fourth week of extraction (Amler 1969). Buccal bone remodeling following tooth extraction has been reported (Arau ´ jo & Lindhe 2005); however, recent studies have shown that extraction of multiple contiguous teeth causes are more extensive buccal bone remodeling as compared to when a single tooth is extracted (Arau ´ jo & Lindhe 2005; Al-Askar et al. 2011; Al-Hezaimi et al. 2011; Al-Shabeeb et al. 2011). The use of ridge preservation protocols for the treatment of osseous defects is well estab- lished (Gapski et al. 2006; Neiva et al. 2008; Avila et al. 2010). A novel approach has been proposed and consists of overbuilding the buc- cal plate with bone grafting materials (Fickl et al. 2009a,b). The rationale behind this modi- fication of the conventional socket grafting approach relies on the addition of extra mate- rial in the area of the ridge where bone resorp- tion is known to be more marked (buccal and coronal), with the hope of compensating natu- ral resorption phenomena. Two animal studies Date: Accepted 26 May 2012 To cite this article: Al-Hezaimi K, Rudek I, Al-Hamdan KS, Javed F, Nooh N, Wang H-L. Efficacy of using a dual layer of membrane (dPTFE placed over collagen) for ridge preservation in fresh extraction sites: A micro-computed tomographic study in dogs. Clin. Oral Imp. Res. , 2012, 1–6 doi: 10.1111/j.1600-0501.2012.02526.x © 2012 John Wiley & Sons A/S 1