Eliane Porto Barboza D.M.D, M.Sc.D, Ph.D
Healing process after tooth extraction
Amler’s study [1] provided a detailed, stage-by-stage description of how the tissues (both bone and soft tissue) heal after a tooth extraction. One of his significant findings was that bone resorption occurs after tooth extraction and this process is a natural part of healing.
After tooth extraction, it is expected that: (1) up to 50% of the original ridge thickness may be lost; (2) resorption will be more pronounced on the buccal (vestibular)aspect than on the lingual/palatal aspect; and (3) the greatest bone loss will occur in the molar regions[2].Since bone tissue provides support for the gingival tissue, when a too this lost and the bone is not preserved, the alveolar ridge collapses, leading to the subsequent loss of gingival support and interdental papilla.
Guided Bone Regeneration(GBR)
The biological principle behind GBR has been successfully employed for alveolar ridge preservation procedures. A resorbable or non-resorbable membrane is used to exclude epithelial and connective tissues and maintain the space previously occupied by the tooth. The importance of preserving the alveolar ridge immediately after extraction using bone substitutes and membranes offers several advantages for the patient, including: (1) reduced alveolar ridge volume loss; (2) accelerated tissue regeneration; (3) reduced need for additional bone grafts; (4) improved future implant stability and placement; and (5) better aesthetic outcomes for prosthetics[3].A recent evidence-based assessment concluded that alveolar ridge preservation significantly decreases the need for additional bone grafting at the time of implant placement[4].
The expanded polytetrafluoroethylene (e-PTFE), with or without titanium support, features porosities that allows connective tissue growth to establish healing while inhibiting epithelial migration. Although e-PTFE membranes are highly predictable, a major disadvantage is the potential for bacterial penetration and subsequent inflammatory response to its porosity. Furthermore, e-PTFE membranes require complete coverage by the flap, which necessitates relaxing incisions and flap manipulation, thereby altering the gingival architecture and mucogingival line position. Dense, non-expanded polytetrafluoroethylene (d-PTFE) membranes, with porosity less than 0.2 μm, resist bacterial incorporation into their structure, allowing for exposure in the oral cavity with a low risk of infection. In 1995, Bartee [5] was the first to report clinical cases where d-PTFE membranes were intentionally exposed for 21 days. Scanning electron microscopy revealed fibroblast-like cells on the inner surface of the membrane, while bacterial colonies were only observed on the outer surface. Subsequent human studies [6-8]on intentionally exposed d-PTFE membranes showed favorable clinical and histological results, including the formation of keratinized gingiva and absence of inflammation.
Increasing keratinized tissue
In addition to the need for sufficient bone volume for implant placement, the presence of keratinized tissue around implants is also critical for maintaining peri-implant health. Patients with a thin periodontal phenotype were 4.5 times more likely to develop peri-implant disease[9], and the lack of keratinized mucosa around implants was associated with increased plaque accumulation, inflammation, tissue recession, and loss of attachment[10].We conducted a randomized clinical trial[7]using intentionally exposed d-PTFE membranes in 15 post-extraction alveoli and demonstrated a mean gain in keratinized tissue of 6.60 ± 2.84 mm after 90 days, compared to 1.40 ± 1.40 mm in control sites that did not receive membranes. We concluded that d-PTFE membranes can be predictably used to increase the zone of keratinized tissue in preparation for future dental implant placement(Fig. 1).
Figure 1: A. Membrane in place, immediately after tooth extraction; B. Tissue aspect immediately after membrane removal (28 days after membrane placement); Sixty-days after membrane removal.
Another study from our group[8]aimed to assess the clinical, histological, and biomolecular aspects of newly formed tissues in post-extraction alveoli and compared dimensional changes using d-PTFE membranes. Twenty human lower molar and premolar alveoli were selected. The test group (10 sites) received a membrane that was intentionally exposed for 28 days, while the control group (10 sites) did not receive a membrane. Clinically, both the test and control groups showed an average gain in keratinized gingiva of 4.3 ± 1.2 mm and 2.5 ± 2.2 mm, respectively. The mucogingival line remained unchanged in both groups. Bone height reduction occurred in both groups, with a mean variation of 0.6 mm to 1.8 mm. Histologically, osteoblasts adjacent to osteoid tissue and trabecular bone composed of young and lamellar bone were observed in both groups, with no inflammatory response. The study also demonstrated that the use of d-PTFE membranes for alveolar ridge preservation resulted in greater formation of keratinized tissue. Biomolecular analysis indicated no influence of the membrane on the healing process, confirming the inert nature of the biomaterial.
In our course, you will learn:
·The science behind alveolar bone resorption and why ARP is crucial for maintaining implant site quality.
·The role of membranes in ARP, not just to secure graft material but also to guide
tissue regeneration and prevent undesirable epithelial invasion—key to
achieving optimal bone formation.
·How intentional membrane exposure can lead to increased keratinized gingiva, enhancing soft tissue quality for future implant success (Fig. 2).
·Effective ARP techniques, including the pocket flap, the use of bone substitutes
that act as scaffolds to promote natural bone healing without triggering immune
responses and d-PTFE membrane placement. With expert-led demonstrations and detailed discussions on the materials and techniques used in ARP, our course will equip you with the knowledge and hands-on experience to enhance your clinical practice, improve patient outcomes, and ensure a more predictable future for your implant placements. Join us to discover how you can leverage ARP to elevate your practice and deliver lasting, natural results for your patients.
Eliane Barboza, DMD, MSD, DScD earned her dental degree from the Fluminense Federal University in Brazil. She then earned her master’s degree in periodontics and doctorate degree in the science of dentistry and residency from Boston University. Dr. Barboza is board-certified by the American Board of Periodontology. She is the director of periodontics at LECOM School of Dental Medicine.
Dr. Barboza will present the course “Alveolar Ridge Preservation Using Bone Graft and Membrane Workshop” on Thursday, June 19, from 2-5 PM at the Florida Dental Convention. Learn more and register at www.floridadentalconvention.com.
References
Figure 2:A. Extraction site; B. d-PTFE membrane in place. C. Thirty days after membrane removal.
1. AmlerMH. The time sequence of tissue regeneration in human extraction wounds. Oral Surg Oral Med Oral Pathol. 1969;27:309-18.
2.Araújo GA, Silva CO, Misawa M, Sukekava F. Alveolar socket healing: what can we learn? Periodontol 2000 2015;68:122-134.
3.PagniG, Pellegrini G, Giannobile WV, Rasperini G. Postextraction alveolar ridge pres-ervation: biological basis and treatments. Int J Dent 2012;2012:1-13.
4. Barootchi S, Tavelli L, Majzoub J, Stefanini M, Wang HL, Avila-Ortiz G. Alveolar ridgepreservation:Complications and cost-effectiveness. Periodontol 2000. 2023Jun;92(1):235-262.
5. Bartee BK. The use of high-density polytetrafluoroethylene membrane to treat osseousdefects: clinical reports. Implant Dent 1995;4:21–26.
6.Barboza EP, Stutz B, Ferreira VF, Carvalho W. Guided bone regeneration using nonexpanded polytetrafluoroethylene membranes in preparation for dental implant placements–A report of 420 Cases. Implant Dent 2010;19:2-7.
7.Barboza EP, Stutz B, Mandarino D, Rodrigues DM, FERREIRA VF. Evaluation of a dense polytetrafluoroethylene membrane to increase keratinized tissue: a randomized controlled clinical trial. Implant Dent 2010;23:289-294.
8. Mandarino D, Luz D, Moraschini V, Rodrigues DM, Barboza ESP. Alveolar ridge preservation using a non-resorbable membrane: randomized clinical trial with biomolecular analysis. Int J Oral Maxillofac Surg. 2018 Nov;47(11):1465-1473.
9. Casado PL, Canullo L, Filardy A, Granjeiro J, Barboza EP, Duarte MEL.Interleukins1-β and 10 expressions in the peri-implant crevicular fluid from patients with untreated perimplant disease. Implant Dent 2013;22:143-160. 10.Lin GH, Chan HL, Wang HL. The significance of keratinized mucosa on implant health: A systematic review. J Periodontol. 2013;84:1755–17
Beyond the Bite 