Clinical Advances in Periodontics Vol. 7, No. 4, November 2017 : Page-207

CASE SERIES Protocol for Maintaining Alveolar Ridge Volume in Molar Immediate Implant Sites Thomas M. Johnson,* † Joshua P. Berridge,* † and Dmitry Baron* Introduction: Numerous biomaterials are available for augmenting bone around dental implants. In contained extrac-tion sockets, a demineralized freeze-dried bone allograft (DFDBA) appears capable of maintaining dimensional stability of the alveolar ridge as well as mineralized alternatives but may yield a higher percentage of new vital bone. When DFDBA is used in large horizontal gap defects at molar immediate implant sites, graft containment and protection must occur through provisional restoration, an anatomic custom healing abutment, or by other means. Case Series: Two mandibular molar immediate implant sites received DFDBA covered by dense polytetrafluoroethy-lene membranes. Conclusion: The present report suggests a protocol for maintaining favorable dimensional stability of the alveolar ridge at molar immediate implant sites, while possibly minimizing residual peri-implant biomaterial. Clin Adv Periodontics 2017;7:207-214. Key Words : Allografts; biocompatible materials; bone regeneration; dental implants; polytetrafluoroethylene; wound healing. Background It is well understood that tooth extraction, with or without flap reflection, will result in modeling of alveolar bone and substantial loss of horizontal and vertical ridge dimensions. 1,2 Ridge preservation procedures can partially mitigate this volumetric bone loss. 2 One study suggested that the smallest overall reduction in the horizontal ridge dimension after tooth extraction occurred when immediate dental implant placement was performed. 3 For replacement of teeth in the esthetic zone, the authors of the present report favor avoiding flap reflection, placing an immediate implant, and sealing an allograft in the * United States Army Advanced Education Program in Periodontics, Fort Gordon, GA. † horizontal defect using a well-crafted provisional restoration. The same procedure can be used in the replacement of a molar tooth, although with added chair time, expense, and complexity compared with a ridge preservation procedure. Moreover, immediate implants do not always achieve adequate insertion torque to support a provisional restoration or custom healing abutment. How, then, are clinicians to deal with large gap defects between implant platforms and molar extraction socket walls? Molar immediate implants are not new. However, the present report proposes a simple protocol using specific materials to achieve favorable clinical results with immediate implant placement in molar extraction sites. Department of Periodontics, Army Postgraduate Dental School, Uniformed Services University of the Health Sciences, Fort Gordon, GA. Clinical Presentation, Case Management, and Clinical Outcomes Case 1 A 49-year-old male patient presented on April 30, 2015, to Tingay Dental Clinic, Fort Gordon, Georgia, with Clinical Advances in Periodontics, Vol. 7, No. 4, November 2017 Submitted April 19, 2017; accepted for publication July 3, 2017 doi: 10.1902/cap.2017.170026 207

Protocol For Maintaining Alveolar Ridge Volume In Molar Immediate Implant Sites

Thomas M. Johnson, Joshua P. Berridge, and Dmitry Baron

Introduction: Numerous biomaterials are available for augmenting bone around dental implants. In contained extraction sockets, a demineralized freeze-dried bone allograft (DFDBA) appears capable of maintaining dimensional stability of the alveolar ridge as well as mineralized alternatives but may yield a higher percentage of new vital bone. When DFDBA is used in large horizontal gap defects at molar immediate implant sites, graft containment and protection must occur through provisional restoration, an anatomic custom healing abutment, or by other means.

Case Series: Two mandibular molar immediate implant sites received DFDBA covered by dense polytetrafluoroethylene membranes.

Conclusion: The present report suggests a protocol for maintaining favorable dimensional stability of the alveolar ridge at molar immediate implant sites, while possibly minimizing residual peri-implant biomaterial. Clin Adv Periodontics 2017;7:207-214.

Key Words: Allografts; biocompatible materials; bone regeneration; dental implants; polytetrafluoroethylene; wound healing.

Background

It is well understood that tooth extraction, with or without flap reflection, will result in modeling of alveolar bone and substantial loss of horizontal and vertical ridge dimensions.1,2 Ridge preservation procedures can partially mitigate this volumetric bone loss.2 One study suggested that the smallest overall reduction in the horizontal ridge dimension after tooth extraction occurred when immediate dental implant placement was performed.3 For replacement of teeth in the esthetic zone, the authors of the present report favor avoiding flap reflection, placing an immediate implant, and sealing an allograft in the horizontal defect using a well-crafted provisional restoration. The same procedure can be used in the replacement of a molar tooth, although with added chair time, expense, and complexity compared with a ridge preservation procedure. Moreover, immediate implants do not always achieve adequate insertion torque to support a provisional restoration or custom healing abutment. How, then, are clinicians to deal with large gap defects between implant platforms and molar extraction socket walls? Molar immediate implants are not new. However, the present report proposes a simple protocol using specific materials to achieve favorable clinical results with immediate implant placement in molar extraction sites.

Clinical Presentation, Case Management, and Clinical Outcomes

Case 1

A 49-year-old male patient presented on April 30, 2015, to Tingay Dental Clinic, Fort Gordon, Georgia, with non-restorable tooth #19. A periodontics resident (DB) fully discussed alternative therapies with the patient, who elected extraction with immediate implant placement. Risks, benefits, and complications of the procedure were explained, and the patient provided written consent for treatment. Tooth #19 was carefully removed, and a 5 X 11.5 mm implant‡ was placed with 45-Ncm insertion torque (Figs. 1 through 3). Demineralized freeze-dried bone allograftx (DFDBA) was placed in the peri-implant defect. Limited gingival flaps were reflected to allow stabilization of a 12 24 mm dense polytetrafluoroethylene (dPTFE) membrane.║ PTFE sutures{ stabilized the buccal and lingual flaps (Fig. 4). Tooth brushing in the mandibular left posterior sextant was withheld for 2 weeks; the patient used chlorhexidine plaque control until normal oral hygiene measures could be reinstituted. The patient received postoperative analgesics and completed a 1-week course of amoxicillin (500 mg three times daily). Sutures were removed at day 14 after surgery, and the tightly adherentmembrane was carefully freed from the surrounding tissue and removed using a dental explorer at day 30 without need for local anesthesia. At 5 months after surgery (Fig. 5), a healing abutment was placed. Peri-implant mucosa aroundimplant#19appeared healthy in the period after restoration; the final crown is shown in Figures 6 and 7.

Case 2

In Case 2, informed consent, extraction technique, biomaterial, membrane, sutures, medications, and oral hygiene regimen were the same as described in Case 1. A 31-yearold male patient presented to Tingay Dental Clinic, Fort Gordon, Georgia, on May 25, 2016, with non-restorable tooth #30. A periodontics resident (JPB) placed an immediate implant# (5 13 mm) in accordance with the presented protocol (Figs. 8 through 14).

Discussion

Periodontics literature is replete with histologic evaluations of bone grafts, bone derivatives and substitutes, and biologic amplifiers used in a wide variety of clinical indications. 4-12 When these materials have been used in implant site development, most reports illustrate that the implant is ultimately not placed in a ridge indistinguishable from native bone.4-12 Rather, the implant appears anchored in an amalgamation of new vital bone and marrow, residual biomaterial, and connective tissue/other elements in various proportions (Table 1).4-12 Even so, contemporary dental implants placed under such provisions display survival and success rates comparable to implants placed in native bone.13 Depending on the biomaterial used, defect configuration, surgical approach, and healing interval, the proportion of vital bone may vary considerably. In perspective, an animal model suggested that application of bone morphogenetic protein-2 and provision of space maintenance may result in bone formation histologically similar to the immediate resident bone.14 Investigators have consistently presented xenograft histology showing new vital bone in direct approximation with graft particles but little or no xenograft biodegradation.6,10-12 Conversely, DFDBA appears to degrade more readily, permitting additional new bone formation. A series of studies conducted at University of Texas Health Science Center San Antonio showed no meaningful difference between DFDBA and FDBA relative to dimensional stability of the alveolar ridge; however, DFDBA or a combination of DFDBA and FDBA was superior to FDBA alone with respect to new vital bone formation at reentry surgery.5,7 Ridge preservation procedures using DFDBA and long (18 to 20 weeks) observation periods displayed a higher percentage of vital bone on reentry compared with short (8 to 10 weeks) intervals.4 Although no critical percentage of new vital bone formation in a grafted socket or ridge has been defined, maximal vital bone–implant contact is intuitively the preferred outcome. Thus, in extraction sockets with intact bony walls, DFDBA appears preferable to other available options.

When expanded PTFEmembranes are exposed to the oral environment, bacteria penetrate the barrier, colonizing the membrane thickness and alveolar surface.15 Once bacteria contaminate the site, little to no regeneration can be expected. However, exposed dPTFE membranes appear to adequately protect allograft material against bacteria for at least 4 weeks, as shown in the presented cases.16 The proposed technique requires sufficient flap reflection for subgingival membrane stabilization even when tooth extraction occurs using a flapless technique. Thus, the vulnerable buccal bone is traumatized. However, some evidence suggests that a non-resorbable membrane placed between the periosteum and buccal bone surface positively influences final buccal bone thickness around immediate implants.17

Successful immediate implant placement is achievable without use of any membrane or biomaterial.3,18 However, when maintenance of peri-implant alveolar ridge volume is intended, use of a protected and contained biomaterial may be warranted.1-3 Exposed bioabsorbable membranes have achieved favorable clinical outcomes and alveolar ridge stability,2,11 although some clinicians suggest that early degradation limits bioabsorbable membrane efficacy without flap advancement and wound closure.16 Presently, a DFDBA–dPTFE membrane combination has produced favorable clinical outcomes in molar immediate implant sites. Controlled clinical and confirmative biologic study of this technique is appropriate.

Summary

Why are these cases new information?

■ This report defines a protocol for managing molar immediate implant sites, leveraging apparent advantages of DFDBA and dPTFE membranes to maintain alveolar ridge dimensions and possibly minimize residual peri-implant biomaterial particles.

What are the keys to successful management of these cases?

■ Minimally traumatic extraction technique, optimal implant positioning, and an intimate seal of graft material with the dPTFE membrane appear important considerations.

What are the primary limitations to success in these cases?

■ In sites exhibiting dehiscence or fenestration defects, ridge preservation with secondary implant placement is preferred.

Acknowledgments

The authors thank Professor Ulf M.E. Wikesjo , Department of Periodontics, Oral Biology Laboratory for Applied Periodontal & Craniofacial Regeneration, Augusta University, The Dental College of Georgia, Augusta, Georgia, for his assistance with editing the manuscript. The authors also thank CPT Nathan Kosiba, US Army Advanced Education Program in Prosthodontics, Fort Gordon, Georgia, for providing the restorative treatment in these cases. The views expressed in this manuscript are those of the authors and do not necessarily reflect the official policy of the US Government, Department of Defense, Department of Army, US Army Medical Department, or Uniformed Services University of the Health Sciences. The authors report no conflicts of interest related to this case series.

CORRESPONDENCE:

Dr. Thomas M. Johnson, 320 East Hospital Rd., Fort Gordon, GA 30905. E-mail: thomas.m.johnson34.mil@mail.mil.

References

1.Schropp L, Wenzel A, Kostopoulos L, Karring T. Bone healing and soft tissue contour changes following single-tooth extraction: A clinical and radiographic 12-month prospective study. Int J Periodontics Restorative Dent 2003;23:313-323.

2.Iasella JM, Greenwell H, Miller RL, et al. Ridge preservation with freeze-dried bone allograft and a collagen membrane compared to extraction alone for implant site development: A clinical and histologic study in humans. J Periodontol 2003;74:990-999.

3.Covani U, Bortolaia C, Barone A, Sbordone L. Bucco-lingual crestal bone changes after immediate and delayed implant placement. J Periodontol 2004;75:1605-1612.

4.Whetman J, Mealey BL. Effect of healing time on new bone formation after tooth extraction and ridge preservation with demineralized freezedried bone allograft: A randomized controlled clinical trial. J Periodontol 2016;87:1022-1029.

5.Borg TD, Mealey BL. Histologic healing following tooth extraction with ridge preservation using mineralized versus combined mineralizedd emineralized freeze-dried bone allograft: A randomized controlled clinical trial. J Periodontol 2015;86:348-355.

6.Urban IA, Nagursky H, Lozada JL, Nagy K. Horizontal ridge augmentation with a collagen membrane and a combination of particulated autogenous bone and anorganic bovine bone-derived mineral: A prospective case series in 25 patients. Int J Periodontics Restorative Dent 2013;33:299-307.

7.Wood RA, Mealey BL. Histologic comparison of healing after tooth extraction with ridge preservation using mineralized versus demineralized freeze-dried bone allograft. J Periodontol 2012;83:329-336.

8.Kolerman R, Goshen G, Joseph N, Kozlovsky A, Shetty S, Tal H. Histomorphometric analysis of maxillary sinus augmentation using an alloplast bone substitute. J Oral Maxillofac Surg 2012;70:1835- 1843.

9.Acocella A, Bertolai R, Colafranceschi M, Sacco R. Clinical, histological and histomorphometric evaluation of the healing of mandibular ramus bone block grafts for alveolar ridge augmentation before implant placement. J Craniomaxillofac Surg 2010;38:222-230.

10.Nevins ML, Camelo M, Nevins M, et al. Minimally invasive alveolar ridge augmentation procedure (tunneling technique) using rhPDGF-BB in combination with three matrices: A case series. Int J Periodontics Restorative Dent 2009;29:371-383.

11.Norton MR, Odell EW, Thompson ID, Cook RJ. Efficacy of bovine bone mineral for alveolar augmentation: A human histologic study. Clin Oral Implants Res 2003;14:775-783.

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13.Fiorellini JP, Nevins ML. Localized ridge augmentation/preservation. A systematic review. Ann Periodontol 2003;8:321-327.

14.Wikesjo¨ UM, Qahash M, Polimeni G, et al. Alveolar ridge augmentation using implants coated with recombinant human bone morphogenetic protein-2: Histologic observations. J Clin Periodontol 2008;35:1001-1010.

15.Simion M, Baldoni M, Rossi P, Zaffe D. A comparative study of the effectiveness of e-PTFE membranes with and without early exposure during the healing period. Int J Periodontics Restorative Dent 1994;14: 166-180.

16.Barber HD, Lignelli J, Smith BM, Bartee BK. Using a dense PTFE membrane without primary closure to achieve bone and tissue regeneration. J Oral Maxillofac Surg 2007;65:748-752.

17.Park SY, Kye SB, Yang SM, Shin SY. The effect of non-resorbable membrane on buccal bone healing at an immediate implant site: An experimental study in dogs. Clin Oral Implants Res 2011;22:289-294.

18.Botticelli D, Berglundh T, Buser D, Lindhe J. The jumping distance revisited: An experimental study in the dog. Clin Oral Implants Res 2003;14:35-42.

indicates key references.


United States Army Advanced Education Program in Periodontics, Fort Gordon, GA.

† Department of Periodontics, Army Postgraduate Dental School, Uniformed Services University of the Health Sciences, Fort Gordon, GA.

Submitted April 19, 2017; accepted for publication July 3, 2017

doi: 10.1902/cap.2017.170026

Read the full article at http://onlinedigeditions.com/article/Protocol+For+Maintaining+Alveolar+Ridge+Volume+In+Molar+Immediate+Implant+Sites/2908976/445120/article.html.

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