Socket Preservation with D-PTFE Membrane: Histologic Analysis of the Newly Formed Matrix at Membrane Removal

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Socket Preservation with d-PTFE Membrane: Histologic Analysis of the Newly Formed Matrix at Membrane Removal

Domenica Laurito, DDS, PhD1/Riccardo Cugnetto, DDS2 Adequate alveolar ridge volume is Marco Lollobrigida, DDS1/Fabrizio Guerra, MD, DDS3 a prerequisite for successful implant Annarita Vestri, PhD4/Francesca Gianno, MD5 placement. Postextraction bone Sandro Bosco, MD6/Luca Lamazza, DMD, PhD2 resorption can significantly affect 3 Alberto De Biase, MD, DDS implant-related esthetics as well as long-term implant survival. This study aimed to evaluate the efficacy of an exposed high-density After tooth extraction, the heal- polytetrafluoroethylene (d-PTFE) membrane in preventing epithelial migration ing process leads to closure of the in postextraction sockets. For this purpose, a histologic description of the newly socket.1 However, this process is not formed soft tissue underlying the membrane is presented. The periodontal status of purely reparative; it involves an unfa- the adjacent teeth was also evaluated to assess the gingival response. Ten premolar extraction sockets were treated. After tooth extraction, the sockets were filled with vorable loss of hard and soft tissues. nanocrystalline hydroxyapatite and covered with d-PTFE membranes. Subperiosteal The first phase of healing consists of pockets were created to ensure the stability of the membranes. Membranes were blood clot formation. The clot is then left intentionally exposed and were atraumatically removed after 28 days. At that replaced by a granulation tissue that, time, a bioptic specimen of the newly formed soft tissue under the membranes through migration of mesenchymal was taken. All the histologic samples showed a dense connective tissue without cells and synthesis of collagen fibers, epithelial cells and no signs of foreign body reaction. No significant variation of the periodontal indices was observed on the teeth adjacent to the extraction sites. leads to the formation of a provision- The study results indicate that exposed d-PTFE membranes can prevent epithelial al connective tissue. Osteoid matrix migration in healing sockets without consequences on the periodontal health. is then deposited and starts to min- Int J Periodontics Restorative Dent 2016;36:877–883. doi: 10.11607/prd.2114 eralize from the deepest portion of the socket. The bone initially formed is an immature woven bone that will be replaced by a lamellar bone. Throughout this process, bone resorption can occur due to the loss of the periodontal ligament.2,3 Hence, 1PhD Student, Department of Oral and Maxillofacial Sciences, Division of Oral Surgery, the overall result of these events is Sapienza University of Rome, Rome, Italy. 2Private Practice, Rome, Italy. the closure of the socket in associa- 3Associate Professor, Department of Oral and Maxillofacial Sciences, tion with a dimensional vertical and Division of Oral Surgery, Sapienza University of Rome, Rome, Italy. horizontal loss of the alveolar bone. 4Full Professor, Department of Public Health and Infectious Diseases, Hygiene Unit, 4 Sapienza University of Rome, Rome, Italy. Lekovic et al reported bone resorp- 5Anatomic Pathology Student, Department of Molecular Medicine, Division of Oral Surgery, tion up to 40% of the alveolar height Sapienza University of Rome, Rome, Italy. 6Researcher, Department of Molecular Medicine, Sapienza University of Rome, and 60% of the alveolar width for an- Rome, Italy. terior teeth and premolars 6 months

Correspondence to: Prof Alberto De Biase, Department of Oral and Maxillofacial Surgery, after tooth extraction. Division of Oral Surgery, Via Caserta 6, 00161 Rome, Italy. Socket preservation (SP) in- Email: [email protected] cludes several techniques to mini- ©2016 by Quintessence Publishing Co Inc. mize the dimensional changes in

Volume 36, Number 6, 2016 © 2019 BY QUINTESSENCE PUBLISHING CO, INC. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER. 878 Digital hosting permission provided by the publisher soft and hard tissues after tooth Study design (UNC-15, Hu-Friedy) immediately extraction. Barrier membranes before the surgical procedure (T1). have been used extensively in SP to A total of 10 patients (5 women and Plaque Index (PI), Gingival Index isolate the extraction sites from the 5 men; aged ≥ 18 years; mean age (GI), and bleeding on probing (BoP) oral environment and to guarantee 37.65; age range 24–55), referred were recorded. the blood clot stability.5–8 To serve for maxillary and mandibular pre- A reassessment was planned these purposes, membranes must molar extraction and subsequent for 6 weeks after the SP procedure be impenetrable to cells and must single-tooth implant rehabilitation, (T5). All measurements were taken ensure a space-maintaining effect.9 were enrolled in the present study. by one dental hygienist who was Different techniques have been The indications for dental extraction previously calibrated after an initial described in the literature with included root fracture, advanced training on casts. A clinical follow-up particular concern for the ridge di- periodontal disease, endodontic of the complete healing was finally mensions and the histologic charac- treatment failure, and nonrestorable carried out at 6 months (T6). teristics of the newly formed bone hopeless teeth. at the time of implant placement.10 Subjects presenting any of the Conversely, limited histologic data is following exclusion criteria were not Surgical procedure and available with respect to the soft tis- admitted to the study: materials sue healing in postextraction sockets covered with membranes. The • Systemic diseases/conditions After a mouthrinse with 0.20% aim of the present pilot study was (eg, pregnancy, diabetes, chlorhexidine for 1 minute prior to to investigate the barrier effect of metabolic bone diseases, surgery, local anesthesia (2% mepi- an exposed high-density polytetra- history of malignancy) vacain with 1:100.000 epinephrine) fluoroethylene (d-PTFE) membrane • Long-term steroidal or was administered. All cases were in postextraction sockets, histo- nonsteroidal anti-inflammatory treated by the same operator (D.L.) logically evaluating the underlying drug therapy (Fig 1). Atraumatic extractions were newly formed soft tissue at 28 days. • Heavy smokers performed with a dedicated piezo- Periodontal indices on the teeth ad- (> 10 cigarettes/day) electric device to prevent fracture or jacent to the healing sites were also • Failure to sign the informed fenestration of the facial bone walls. recorded to investigate the effects consent After debridement and irriga- of membrane exposure on the peri- • Unwillingness to return for the tion with sterile saline solution, the odontal tissue. follow-up examinations sockets were filled with nanocrystalline hydroxyapatite (ncHA) (Nano- An informed consent form was Bone, Artoss). Materials and methods signed in accordance with the Nonresorbable d-PTFE mem- Helsinki Declaration of 1975, as re- branes (Cytoplast TXT-200 Singles, The present study was performed at vised in 2008. Osteogenics) were trimmed to fit the Department of Oral and Maxil- An oral hygiene protocol in- and cover the sockets. Two subperi- lofacial Science, Division of Oral Sur- cluding scaling, root planing, and osteal pockets were created buccal gery, Sapienza University of Rome, oral hygiene instructions was estab- and lingual to each extraction site to Italy. Ethical approval was obtained lished for each patient 1 week be- insert the edges of the membrane. from the local Ethics Committee for fore the surgery (T0). For this purpose, the gingival mar- Human Research (protocol number A comprehensive periodontal gins were undermined without a re- 2815/13.06.2013). examination of the tooth to be ex- leasing incision. A space of 1.0 mm tracted and the adjacent teeth was between the membrane and the performed with a periodontal probe adjacent teeth was maintained to

Fig 1 A maxillary second premolar to be Fig 2 Clinical view before membrane Fig 3 Clinical view immediately after mem- extracted. removal (28 days). Plaque accumulation brane removal. was detected on the exposed surface of the membrane.

enhance the reattachment of the width and 2 mm in depth). The cen- The probability values are two-sided, papillae. Membrane stabilization ter of the socket was determined and P < .05 was considered statistical- was obtained with two interrupted with a periodontal probe as the cross ly significant. All analyses were carried sutures at the interdental papillae point between the buccolingual and out with Stata 12 software. and a horizontal mattress suture mesiodistal dimensions from the across the socket (Cytoplast PTFE, midpoint of the alveolar crests. No Osteogenics). The membrane was postoperative therapy was given af- Results left intentionally exposed until re- ter this procedure. moval. Each of the 10 patients in the study Postoperative therapy consisted contributed one extraction site. Of of antibiotics (amoxicillin 875 mg + Histologic analysis the subjects, 5 were smokers (< 10 clavulanic acid 125 mg, twice a day cigarettes per day). All the proce- for 7 days), anti-inflammatories (nime- Specimens were fixed in 10% neu- dures were successfully carried out sulide 100 mg, twice a day for 3 days), tral buffered formalin, dehydrated with no postoperative complica- and 0.20% chlorhexidine mouthrins- through alcohol baths of increasing tion. es (twice a day for 14 days). Patients concentration (70% to 100% ethylic were observed at 7 days (T2), and su- alcohol and xylene) and included in tures were removed at 14 days (T3). paraffin. Sections of 4-µm thickness Clinical evaluation were prepared and stained with hematoxylin-eosin. None of the patients reported any Membrane removal unusual pain and no clinical signs of infection (swelling and suppu- Membranes were atraumatically Statistical analysis ration) were observed until mem- removed at 28 days (T4) without brane removal. Mild inflammation anesthesia (Figs 2 and 3). After the Periodontal indices were statistically of the gingival margins was noted removal, a biopsy of the underlying analyzed. Continuous variables are at T4, and plaque accumulation tissue was performed in the middle presented as median and interquar- was constantly detected on the ex- of the socket with a #11 blade (Bard tile range because the distribution is posed surface of the membranes. Parker). The specimens were mini- not normal. Wilcoxon test was used to Partial epithelialization occurred at mally dimensioned (2 × 2 mm in evaluate differences within the groups. T5 without signs of inflammation

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= Standard deviation 0.50

0.45 0.475

0.40

0.35 0.35

0.30 0.3 0.3 0.25 0.25 0.25 0.20 0.175 0.15 0.125 0.10

0.05 0.075 0.075 0.075 0.05 0 GI PI BoP GI PI BoP GI PI BoP GI PI BoP Mesial T0 Distal T0 Mesial T5 Distal T5

Fig 4 (top) Follow-up at 42 days. Fig 5 Periodontal indices variation. GI = Gingival Index; PI = Plaque Index; BoP = bleeding on probing. Fig 6 (bottom) Follow-up at 6 months. Keratinized tissue had completely covered the socket.

Fig 7 (left) Histologic specimen showing fibroblasts (solid arrowheads) surrounded by connective tissue matrix, with some ncHA granules (open arrowheads) and multinucleated giant cells (arrows). Hematoxylin-eosin staining; original magnification× 10.

Fig 8 (right) At a higher magnification, acute inflammatory cell infiltration of polymorphonuclear granulocytes (open arrows) can be noted. Hematoxylin-eosin staining; original magnification× 20.

(Fig 4). Although all the periodontal Histologic evaluation phlogistic areas with granulation indices were reduced at T5 on both aspect. No signs of foreign-body the mesial (GI from 0.18 to 0.08; PI Ten tissue samples were harvested reaction were present. Giant mul- from 0.30 to 0.25) and the distal at the time of membrane removal. tinucleated osteoclastic-like cells tooth (GI from 0.35 to 0.08; PI from At the microscopic analysis, no ep- were also detectable in associa- 0.48 to 0.25), only the BoP reduc- ithelial cells were detected. All the tion with various ncHA granules. tion on the distal tooth (from 0.30 specimens exhibited a dense con- A network of small blood vessels to 0.05) was statistically significant nective tissue with a large num- within the connective tissue was (P = .046) (Fig 5). A complete epi- ber of fibroblast and inflammatory observed. No bacterial contami- thelialization was observed at T6 in cells (both lymphoplasma cells and nation was observed in any case all cases (Fig 6). neutrophil granulocytes), forming (Figs 7 and 8).

Discussion lactic acid, collagen membranes) even when exposed to the oral envi- is that a second surgical procedure ronment.19 This assumption is based In the present study, the effect of a is not necessary for membrane re- on the disparity between the aver- d-PTFE membrane associated with moval. On the other hand, they age size of bacteria (about 1–2 µm) ncHA was evaluated via clinical ex- require a primary tension-free clo- and the pore diameter. Examining amination and histologic analysis of sure, which can create more prob- d-PTFE membranes with a scanning the newly formed soft tissue under- lems during the primary surgery.14 electron microscope after 21 days lying the membrane. Nonresorbable expanded PTFE exposure, Krauser20 observed no At membrane removal, the orig- (e-PTFE) membranes have been bacterial contamination on the in- inal position of the gingival margins reported to be most effective in ternal surface. In the present study, was unvaried and an underlying soft providing bone regeneration, but a no bacterial cells were observed in tissue was clinically observable. In all second surgery is needed for their the specimens although plaque ac- cases, the d-PTFE membranes con- retrieval.15 Similar to resorbable cumulation was constantly detected tained the graft material and pre- membranes, e-PTFE membranes on the external surface of the mem- vented epithelial migration into the need a complete coverage but branes. Furthermore, the external cavity. No infective complications present a higher incidence of pre- contamination did not negatively af- occurred in the postextraction sites mature spontaneous exposure. fect the periodontal indices on the during the follow-up. The histologic One major problem occurring adjacent teeth. The observed reduc- analysis of the soft tissue samples with flap dehiscence and mem- tion may be related to the postop- showed the presence of a dense brane exposure is infection of the erative therapy with chlorhexidine. connective tissue matrix with mainly healing site. However, different These findings support the idea of fibroblasts and no epithelial cells. outcomes have been described a minimal or absent inflammation in- The GI and PI recorded on the ad- with exposed nonresorbable and duced by the exposed membranes jacent teeth showed no significant resorbable membranes. Exposed e- on the surrounding tissue. differences at the 6-week follow-up, PTFE membranes, due to their high In the esthetic area, SP tech- while a BoP reduction on the distal surface roughness and microporos- niques with d-PTFE membranes tooth was noted. ity, are susceptible to bacterial pen- were demonstrated to preserve The rationale for adopting SP etration and need to be removed.16 the keratinized gingiva (KG). On the techniques is the maintenance of On the contrary, exposed collagen contrary, different studies have re- a sufficient alveolar bone volume membranes usually do not lead to ported a reduction in KG with e-PT- for implant placement. Different infection, although premature deg- FE and resorbable membranes.21,22 protocols, including the use of radation causes a loss of the barrier Maintenance of the original posi- membranes, graft materials, or a function and a reduction in bone re- tion of the gingival margins may combination of both, have been generation.17 From this perspective, contribute to preserve the existing described in the literature. Howev- one of the most relevant topics in keratinized tissue. In addition, the er, there is currently no agreement recent years is the use of intention- secondary epithelialization that fol- about the procedure or the timing. ally exposed occlusive membranes lows membrane removal can further Although some authors have pro- to protect healing extraction sites. increase the keratinized tissue.23 In posed the use of graft materials Bartee and Carr18 were the first au- a series of 420 cases treated with alone to maintain the alveolar vol- thors to extensively describe the use exposed d-PTFE membranes after ume,11,12 the association with barrier of d-PTFE membranes in GBR and tooth extraction, Barboza et al24 re- membranes has been claimed as SP techniques. Due to the 0.2-µm ported the formation of a normal giving better results.13 nanopores, dense membranes have KG and a preserved mucogingival One of the main advantages of been claimed to resist bacterial pen- junction position for all patients at resorbable membranes (eg, poly- etration with a low risk of infection the time of implant placement. The

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results of the present study are in be highlighted since it represents the 5. Mardas N, Chadha V, Donos N. Alveo- accordance with these findings, only separation between the graft lar ridge preservation with guided bone regeneration and a synthetic bone sub- since no infection occurred in any material and the oral environment un- stitute or a bovine-derived xenograft: A case and a complete epithelializa- til the complete epithelialization. randomized, controlled clinical trial. Clin Oral Implants Res 2010;21:688–698. tion could be clinically observed at 6. Barone A, Aldini NN, Fini M, Giardino R, 6 months. Calvo Guirado JL, Covani U. Xenograft Another advantage of exposed Conclusions versus extraction alone for ridge preservation after tooth extraction. A clinical d-PTFE membranes is that they do and histomorphometric study. J Peri- not require a second surgical phase The present study focused exclu- odontol 2008;79:1370–1377. 25 7. Fotek PD, Neiva RF, Wang HL. Compari- to be removed. The removal is sively on soft tissue. The histologic son of dermal matrix and polytetrafluo- also facilitated by the smooth in- analysis of 10 tissue specimens re- roethylene membrane for socket bone ternal surface. In the present study, vealed no epithelial ingrowth or augmentation: A clinical and histologic study. J Periodontol 2009;80:776–785. membrane removal was scheduled bacterial contamination after 28 8. Becker W, Lynch SE, Lekholm U, et al. A at 28 days. According to Barber et days of membrane exposure in comparison of ePTFE membranes alone 23 or in combination with platelet-derived al longer membrane persistence postextraction sockets filled with growth factors and insulin-like growth may lead to an apical migration of ncHA. Although the specimens factor-I or demineralized freeze-dried the flap or a delay in bone forma- may be not representative of the bone in promoting bone formation around immediate extraction socket im- tion. For this reason, the authors whole of the soft tissue under the plants. J Periodontol 1992;63:929–940. suggested a time range for mem- membranes, the histologic findings 9. De Biase A, Catalano G, Vozza I, Lamazza L. Rigenerazione ossea guidata in 40 sedi brane removal between 4 and 6 indicate that the use of d-PTFE can implantari ritardate mediante l’utilizzo di weeks after surgery. exclude epithelial and bacterial cells Biostite e membrana Paroguide. Implan- To the authors’ knowledge, no from the healing sites. tologia 2007;2:33–39. 10. Vignoletti F, Matesanz P, Rodrigo D, histologic analyses of specimens re- Figuero E, Martin C, Sanz M. Surgical pro- trieved at the removal of exposed tocols for ridge preservation after tooth extraction. A systematic review. Clin Oral d-PTFE membranes have been per- Acknowledgments Implants Res 2012;23 (suppl):s22–s38. formed to date. In a recent study on 11. Nemcovsky CE, Serfaty V. 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