- Email: [email protected]
Vertical Ridge Augmentation Using the Modified Shell Technique—A Case Report
DENTAL IMPLANTS
Vertical Ridge Augmentation Using the Modified Shell Technique—A Case Report Michael Stimmelmayr, DMD, PhD,* Jan-Frederik G€ uth, DMD,y Markus Schlee, DMD,z and Florian Beuer, DMD, PhDx Purpose:
Vertical defects of the alveolar crest limit implant placements. Accordingly, hard tissue grafting is essential in a separate procedure before implant placement; however, the outcome of vertical bone augmentation is unpredictable.
Materials and Methods:
This case report describes a new approach to vertical hard tissue grafting using the modified autogenous shell technique. With the help of a bone mill, the bone graft was trimmed to a shell with a thickness of less than 1 mm and seeded to rebuild the vertical dimension of the alveolar ridge. The shell was fixated with titanium microscrews, and the vertical distance between the shell and the residual bone was filled with autogenous particulate bone.
Results:
Wound healing was uneventful. Corticalization was observed across the bone chips, and there was only a small vertical resorption of the shell. Two implants could be inserted above the alveolar nerve into the augmented bone.
Conclusion:
The modified shell technique showed promising results for the reconstruction of vertical bone defects. This technique could decrease the need for bone grafts taken from the iliac crest. Ó 2014 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 72:286-291, 2014
Reconstruction of partially or totally edentulous patients with dental implants has become routine treatment with predictable outcomes in the past 25 years.1 Guided bone regeneration extended the number of possible sites for dental implants in the early 1990s,2 and reliable long-term results also can be observed when implants are placed in augmented bone.3 Initially, space holders were used to provide room for bone regeneration; however, bone substitutes or bone grafts showed better clinical results. Horizontal defects can be reconstructed predictably using membrane techniques in combination with bone substitutes or bone grafts.4-6 However, the predictability of this technique decreases when the size of the defects increases and when vertical defects have to be reconstructed.3,7 It has been shown that there is a critical size of bone defect that cannot be reconstructed with bone substitutes.8
Hence, reconstruction of such defects raises the requirement for augmentation with autogenous bone grafts.9,10 The reconstruction of severe vertical defects of the alveolar crest remains a challenge. Vertical augmentation has been performed mostly with bone grafts from the iliac crest, potentially in combination with distraction osteogenesis, sandwich, or interpositional techniques.3,7,11 Owing to the greater resorption and morbidity of the donor site, intraoral donor sites have become more popular.12-14 Severe 3-dimensional defects can be reconstructed predictably with the modified shell technique using intraoral autogenous bone grafts. Long-term stability of the peri-implant bone and a high implant survival rate have been shown.14-16 In the present study, thin cortical bone shells that were thinned and trimmed with a bone mill were placed horizontally to
*Assistant Professor, Department of Prosthodontics, University of Munich, Munich, Germany; Private Practice in Oral Surgery, Cham,
Address correspondence and reprint requests to Dr Stimmelmayr: Josef-Heilingbrunnerstr 2, 93413 Cham, Germany; e-mail: michael
Germany.
[email protected]
yAssistant Professor, Department of Prosthodontics, University of
Received June 5 2013
Munich, Munich, Germany.
Accepted September 2 2013
zPrivate Practice, Forchheim, Germany.
Ó 2014 American Association of Oral and Maxillofacial Surgeons
xTenured Professor, Department of Prosthodontics, University of
0278-2391/13/01143-9$36.00/0
Munich, Munich, Germany.
http://dx.doi.org/10.1016/j.joms.2013.09.004
286
287
STIMMELMAYR ET AL
reconstruct 3 dimensions. These shells served as a natural barrier membrane by maintaining space and preventing soft tissue ingrowth. Particulate bone was placed in the vertical cavity between the shell and the residual alveolar crest. The technique described in this article is similar to the technique described for horizontal ridge augmentation. However, the shell is placed horizontally to provide vertical space between the shell and the alveolar ridge. To fit the mesiodistal contour of the reconstructed area (straight or curved), the shape of the bone graft taken from the lateral side of the mandibular ramus must fit exactly to recontour the form of the alveolar crest. The present clinical case report describes the surgical procedure step by step, in detail.
FIGURE 1. Vertical bony defect in the region of the left lower first molar and second bicuspid because of aplasia (detail of a Panorex radiograph).
Report of Case
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
The requirements of the Declaration of Helsinki were observed, and the patient gave informed consent for all surgical procedures. This case report documents a retrospective analysis of a surgical technique. The described technique is also a complement of a well-described technique for horizontal augmentation procedures. Therefore, the case report was exempted from the institutional review board approval process. A healthy 26-year-old woman had aplasia of multiple teeth in the upper and lower jaws. In addition to extensive bilaterally maxillary sinus and transversal ridge defects, a severe vertical bone defect was present in the mandible in the region of the left lower first molar and second bicuspid (Fig 1).
line angle of the left lower second molar to the ascending ramus. This relieving incision also was the access for the donor site of the bone graft. A full-thickness flap was elevated and, for tension-free wound closure, the periosteum was slit basally to the flap right at the beginning of surgery to prevent bleeding by the time of membrane placement at the end of the procedure. The bony defect was measured using a periodontal probe to determine the size of the defect, and the bone shell and the cortical plate, respectively, were perforated with a bur for better angiogenesis of the graft. In addition, mesial and distal rests were created for a precise fit of the shell.
SURGICAL PLANNING
Backward planning using a wax-up and a mock-up was performed for prosthodontic reconstruction. The result was transformed to a radio-opaque surgical template, and cone-beam computer tomography (Model 9500 CBCT, Carestream Dental; Kodak, Rochester, NY) was performed for surgical planning. The patient was instructed to take amoxicillin 1,000 mg 3 times a day, ibuprofen 400 mg, and Decortin (Merck KGaA, Darmstadt, Germany) 50 mg (to prevent inflammation and swelling) 1 hour before ridge augmentation. Ibuprofen was continued for 3 days at 3 times a day and the antibiotics for 6 days at 3 times a day after augmentation. Immediately before surgery, the patient rinsed her mouth with a 0.2% chlorhexidine solution for 3 minutes.
GRAFT HARVESTING
The augmented bone was harvested at the left ascending ramus of the mandible. With the help of an ultrasonic knife (Piezosurgery; Mectron, Cologne, Germany), a corticocancellous bone block was obtained. The harvested bone block had a thickness of approximately 3 mm. In a bone mill (Bull Bone Mill; Mondeal, M€ uhlheim an der Donau, Germany), the block was decreased to a thickness of less than 1 mm and used as the shell. The milled bone chips were mixed with autogenous blood and used as particulate bone for the augmentation. The donor site was filled with a collagen fleece (Resorba, Nueremberg, Germany) and closed with interrupted sutures (nylon, 5-0; Resorba). GRAFT PLACEMENT
GRAFT SITE PREPARATION
A midcrestal incision in the region of the left lower first molar and second bicuspid was followed by a sulcular incision along the left lower second molar and first bicuspid, with a relieving incision at the distal
The bone shell was trimmed with a cutting wheel, adjusted with a round bur, and anchored in the residual bone with 2 titanium microscrews, 1.3 mm in diameter 9 mm in the region of the left lower second bicuspid and 1.0 mm in diameter 7 mm in the region
288
VERTICAL RIDGE AUGMENTATION
FIGURE 2. Lateral view of the fixated bone shell shows the huge vertical defect.
FIGURE 4. Postsurgical radiograph shows vertical augmentation and microscrews (detail of a Panorex radiograph).
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
of the left lower first molar (Q-Bone-Grafting Set; Trinon, Karlsruhe, Germany; Fig 2). The vertical space between the shell and the alveolar crest was filled with a mixture of milled bone chips and autogenous blood (Fig 3). The bone graft was covered with a resorbable collagen membrane (BioGide; Geistlich, Wolhusen, Switzerland) and the wound was closed with a coronally advanced flap. To secure the wound margins, deep horizontal mattress sutures (Gore-Tex, 6-0; WL Gore, Flagstaff, AZ) were applied for wound fixation and interrupted sutures (Mopylen, 6-0; Resorba) were applied for wound adaptation. To document the surgical result, a Panorex radiograph (Orthophos 3D; Sirona, Bensheim, Germany) was obtained just after surgery (Fig 4).
grafted site were removed on day 10 after surgery, and the mattress sutures were removed on day 14 after surgery. After 2 weeks, the wound was primarily closed without any signs of inflammation. The patient was provided with a removable dental prosthesis (RDP). Particular attention was paid so that no contact or pressure from the prosthesis was transferred to the gingiva or the graft.
WOUND HEALING
Wound healing showed no complications. The single sutures on the retromolar donor site and on the
FIGURE 3. Bone chips mixed with autogenous blood fill the gap between the shell and the residual bone. Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
IMPLANT PLACEMENT
The patient was instructed to take amoxicillin 1,000 mg 3 times a day and ibuprofen 400 mg 1 hour before implant placement. Ibuprofen was continued for 3 days at 3 times a day and the antibiotics for 6 days at 3 times a day after surgery. Mouth disinfection was performed as described earlier. The integration period of the bone graft was 6 months 24 days. Because of the previous massive augmentation and the coronally advanced flap for wound closure, the displacement of the mucogingival junction had to be replaced during implant placement. Therefore, an incision about 1 mm deep was performed at the mucogingival junction, and a splitthickness flap was sharply dissected for a plasty of the vestibule.17 Then, a midcrestal incision was conducted to cut the periosteum. The periosteum was reflected buccally and a full-thickness flap was reflected lingually to expose the augmented bone (Fig 5). After removal of the 2 microscrews, the implants in the region of the left lower first molar (4.3 mm in diameter 7 mm; Conelog; Camlog Biotechnologies, Wimsheim, Germany) and the region of the left lower second bicuspid (3.8 mm in diameter 9 mm; Screwline Promote Plus; Camlog Biotechnologies) were placed with a positioning guide at the planned positions. Healing abutments were screwed into the 2 implants for open healing. The buccally reflected periosteum
289
STIMMELMAYR ET AL
FIGURE 5. Re-entry 5 months after augmentation shows ideal consolidation of the bone graft and reconstruction of the alveolar crest. Note the formation of a thin cortical plate. Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
and the lingually reflected full-thickness flap were adapted around the healing abutments with a combination of mattress and interrupted sutures (Mopylen 6-0; Resorba), for which all knots were placed on the lingual side. A free gingival graft, taken from the hard palate, was placed and secured with interrupted sutures (Mopylen, 6-0; Resorba) on the periosteum to increase the width of the keratinized gingiva.17 The palatal donor site was covered with a palatal stent (1.5 mm; Erkodent, Pfalzgrafenweiler, Germany) for 5 days to facilitate wound healing. To document the implant positions, a postsurgical Panorex radiograph (Orthophos 3D) was obtained (Fig 6). The RDP was reduced on the basal side to avoid any contact between the RDP and the healing abutments during osseointegration of the implants. Wound healing was uneventful. The single sutures were removed on day 8, and the mattress sutures were removed on day 14 after implant placement (Fig 7).
FIGURE 7. Surgical result after vertical ridge augmentation, implant placement in the region of the left lower first molar and second bicuspid, and extension of the keratinized gingiva with a free gingival graft. Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
Owing to the loss of vertical dimension because of the multiple aplasias, the implants were restored with long-term provisional for progressive bone loading and to test the new vertical dimension. A radiograph after a loading period of 6 months showed biological bone resorption around the implants and stable vertical bone regeneration. A potential small bone sequestration was noticeable distal to the implant in the region of the left lower second bicuspid (Fig 8). However, no clinical signs of an inflammation were present. This will be checked at the 12-month recall.
Discussion This case ended with a primary wound closure and uneventful bone healing. Nearly 7 months after the vertical augmentation procedure, the planned implants could be inserted at the proper positions in
FIGURE 6. Postsurgical radiograph shows stabile vertical augmentation and implants (detail of a Panorex radiograph).
FIGURE 8. Six-month follow-up radiograph shows implants restored with a long-term provision for progressive bone loading. A potential small bone sequestration is noticeable distal to the implant in the region of the left lower second bicuspid.
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
290 a second-stage surgery. In the region of the left lower first molar, slight vertical resorption of the horizontally placed shell was observed. Using the radiographs after the augmentation procedure and before implant placement, the heads of the titanium microscrews served as detectors for the amount of resorption. Because of this minimal vertical resorption, the implant in the region of the left lower first molar was placed slightly deeper. Placing a thick cortical bone block as an onlay graft can lead to sequestration of the block because of poor or missing revascularization and revitalization. This was noted in some cases several years after the augmentation procedure. With the help of the shell technique described earlier, the regeneration of vital bone was observed.13-16 Filling the vertical gap with particulate bone has 2 advantages. First, it is easier to fill the gap with bone chips than to trim a bone block exactly to a form that fits between the shell and the residual bone. Second, angiogenesis of bone chips seems favorable compared with a thick cortical bone block, which represents a biological benefit. Shells thinner than 1 mm provide the vertical dimension of the graft and prevent the resorption of particulate bone chips. Perforations of the cortical plate of the residual bone allow a blood supply to and revascularization of the bone chips. However, there is no evidence that these perforations lead to better bone healing. In most animal studies, no perforations were made. In a personal comment, Prof Dr Frank Schwarz (personal communication, August 21, 2010) mentioned that perforations can never be performed similarly and therefore are not performed in studies comparing different augmentation procedures. He suggested always perforating the cortical bone plate in clinical situations for better angiogenesis. In the present case, natural bleeding of the implant bed during implant placement suggested vital bone cells. The need for circumferential keratinized gingiva around implants has been a controversial issue for years. Evidence of bone loss is still pending, however, and the available data clearly suggest that implants should be surrounded by keratinized gingiva wherever possible. This is particularly difficult in the posterior mandible after long-standing tooth loss or disuse atrophy. As shown in this case report, hard tissue augmentation requires primary wound closure and leads to vestibular flattening and displacement of the mucogingival line. Therefore, a secondary soft tissue grafting was conducted simultaneously with implant placement. This technique offers long-term stability of the keratinized gingiva around dental implants.17 Harvesting a bone graft from the iliac crest for vertical ridge augmentation is a major surgical procedure compared with the modified shell technique described in
VERTICAL RIDGE AUGMENTATION
the present study.7 The donor site is intraoral and often in the same quadrant as the region where augmentation is required. Therefore, in many cases, especially for augmentation of defects in the lower jaw, only 1 wound is opened for augmentation and for harvesting the shell and bone chips. Adjusting the thickness of the bone shell with the bone mill is convenient and uncomplicated and allows simultaneous retrieval of the bone chips. Also, the technique is relatively straightforward, as shown previously for horizontal hard tissue augmentation.14 Future clinical studies are needed to evaluate the amount of vertical bone regeneration quantitatively and histologically. A case series with data acquisition of 19 cases is under way. In this case report, the vertical reconstruction of the alveolar crest was conducted using the modified shell technique. This has a major influence for long-term stability of an implant-supported dental prosthesis. The potential of only 1 donor site might help to decrease postsurgical morbidity and complication rates. The vertical shell technique described offers 1) possible vertical bone reconstruction, 2) intraoral harvesting of autogenous bone for major vertical augmentation procedures, 3) regeneration of vital bone, and 4) proper conditions for implant placement.
References 1. Esposito M, Worthington HV, Coulthard P: Interventions for replacing missing teeth: Treatment of perimplantitis. Cochrane Database Syst Rev, 2004 CD004970 2. Nyman S, Lang NP, Buser D, et al: Bone regeneration adjacent to titanium dental implants using guided tissue regeneration: A report of two cases. Int J Oral Maxillofac Implants 5:9, 1990 3. Chiapasco M, Casentini P, Zaniboni M: Bone augmentation procedures in implant dentistry. Int J Oral Maxillofac Implants 24(suppl):237, 2009 4. Buser D, Dula K, Belser U, et al: Localized ridge augmentation using guided bone regeneration. 1. Surgical procedure in the maxilla. Int J Periodontics Restorative Dent 13:29, 1993 5. Buser D, Dula K, Belser UC, et al: Localized ridge augmentation using guided bone regeneration. II. Surgical procedure in the mandible. Int J Periodontics Restorative Dent 15:10, 1995 6. Chiapasco M, Zaniboni M, Boisco M: Augmentation procedures for the rehabilitation of deficient edentulous ridges with oral implants. Clin Oral Implants Res 17(suppl 2):136, 2006 7. Jensen SS, Terheyden H: Bone augmentation procedures in localized defects in the alveolar ridge: Clinical results with different bone grafts and bone-substitute materials. Int J Oral Maxillofac Implants 24(suppl):218, 2009 8. Block MS, Degen M: Horizontal ridge augmentation using human mineralized particulate bone: Preliminary results. J Oral Maxillofac Surg 62:67, 2004 9. Merli M, Migani M, Esposito M: Vertical ridge augmentation with autogenous bone grafts: Resorbable barriers supported by osteosynthesis plates versus titanium-reinforced barriers. A preliminary report of a blinded, randomized controlled clinical trial. Int J Oral Maxillofac Implants 22:373, 2007 10. Moghadam HG: Vertical and horizontal bone augmentation with the intraoral autogenous J-graft. Implant Dent 18:230, 2009 11. Aghaloo TL, Moy PK: Which hard tissue augmentation techniques are the most successful in furnishing bony support for implant placement? Int J Oral Maxillofac Implants 22:49, 2007
STIMMELMAYR ET AL 12. Sbordone C, Toti P, Guidetti F, et al: Volume changes of iliac crest autogenous bone grafts after vertical and horizontal alveolar ridge augmentation of atrophic maxillas and mandibles: A 6-year computerized tomographic follow-up. J Oral Maxillofac Surg 70:2559, 2012 13. Khoury F, Ponte A: The 3-dimensional reconstruction of the alveolar crest with mandibular bone block graft: A clinical study. Int J Oral Maxillofac Implants 19:795, 2004 14. Stimmelmayr M, Guth JF, Schlee M, et al: Use of a modified shell technique for three-dimensional bone grafting: Description of a technique. Aust Dent J 57:93, 2012
291 15. Khoury F, Khoury C: Mandibular bone block grafts; instrumentation, harvesting technique and application. J Par Impl Orale 25: 15, 2006 16. Khoury F, Antoun H, Missika P: Bone Augmentation in Oral Implantology. London, UK, Quintessence, 2007 17. Stimmelmayr M, Stangl M, Edelhoff D, et al: Clinical prospective study of a modified technique to extend the keratinized gingiva around implants in combination with ridge augmentation: One-year results. Int J Oral Maxillofac Implants 26: 1094, 2011
Vertical Ridge Augmentation Using the Modified Shell Technique—A Case Report Michael Stimmelmayr, DMD, PhD,* Jan-Frederik G€ uth, DMD,y Markus Schlee, DMD,z and Florian Beuer, DMD, PhDx Purpose:
Vertical defects of the alveolar crest limit implant placements. Accordingly, hard tissue grafting is essential in a separate procedure before implant placement; however, the outcome of vertical bone augmentation is unpredictable.
Materials and Methods:
This case report describes a new approach to vertical hard tissue grafting using the modified autogenous shell technique. With the help of a bone mill, the bone graft was trimmed to a shell with a thickness of less than 1 mm and seeded to rebuild the vertical dimension of the alveolar ridge. The shell was fixated with titanium microscrews, and the vertical distance between the shell and the residual bone was filled with autogenous particulate bone.
Results:
Wound healing was uneventful. Corticalization was observed across the bone chips, and there was only a small vertical resorption of the shell. Two implants could be inserted above the alveolar nerve into the augmented bone.
Conclusion:
The modified shell technique showed promising results for the reconstruction of vertical bone defects. This technique could decrease the need for bone grafts taken from the iliac crest. Ó 2014 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 72:286-291, 2014
Reconstruction of partially or totally edentulous patients with dental implants has become routine treatment with predictable outcomes in the past 25 years.1 Guided bone regeneration extended the number of possible sites for dental implants in the early 1990s,2 and reliable long-term results also can be observed when implants are placed in augmented bone.3 Initially, space holders were used to provide room for bone regeneration; however, bone substitutes or bone grafts showed better clinical results. Horizontal defects can be reconstructed predictably using membrane techniques in combination with bone substitutes or bone grafts.4-6 However, the predictability of this technique decreases when the size of the defects increases and when vertical defects have to be reconstructed.3,7 It has been shown that there is a critical size of bone defect that cannot be reconstructed with bone substitutes.8
Hence, reconstruction of such defects raises the requirement for augmentation with autogenous bone grafts.9,10 The reconstruction of severe vertical defects of the alveolar crest remains a challenge. Vertical augmentation has been performed mostly with bone grafts from the iliac crest, potentially in combination with distraction osteogenesis, sandwich, or interpositional techniques.3,7,11 Owing to the greater resorption and morbidity of the donor site, intraoral donor sites have become more popular.12-14 Severe 3-dimensional defects can be reconstructed predictably with the modified shell technique using intraoral autogenous bone grafts. Long-term stability of the peri-implant bone and a high implant survival rate have been shown.14-16 In the present study, thin cortical bone shells that were thinned and trimmed with a bone mill were placed horizontally to
*Assistant Professor, Department of Prosthodontics, University of Munich, Munich, Germany; Private Practice in Oral Surgery, Cham,
Address correspondence and reprint requests to Dr Stimmelmayr: Josef-Heilingbrunnerstr 2, 93413 Cham, Germany; e-mail: michael
Germany.
[email protected]
yAssistant Professor, Department of Prosthodontics, University of
Received June 5 2013
Munich, Munich, Germany.
Accepted September 2 2013
zPrivate Practice, Forchheim, Germany.
Ó 2014 American Association of Oral and Maxillofacial Surgeons
xTenured Professor, Department of Prosthodontics, University of
0278-2391/13/01143-9$36.00/0
Munich, Munich, Germany.
http://dx.doi.org/10.1016/j.joms.2013.09.004
286
287
STIMMELMAYR ET AL
reconstruct 3 dimensions. These shells served as a natural barrier membrane by maintaining space and preventing soft tissue ingrowth. Particulate bone was placed in the vertical cavity between the shell and the residual alveolar crest. The technique described in this article is similar to the technique described for horizontal ridge augmentation. However, the shell is placed horizontally to provide vertical space between the shell and the alveolar ridge. To fit the mesiodistal contour of the reconstructed area (straight or curved), the shape of the bone graft taken from the lateral side of the mandibular ramus must fit exactly to recontour the form of the alveolar crest. The present clinical case report describes the surgical procedure step by step, in detail.
FIGURE 1. Vertical bony defect in the region of the left lower first molar and second bicuspid because of aplasia (detail of a Panorex radiograph).
Report of Case
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
The requirements of the Declaration of Helsinki were observed, and the patient gave informed consent for all surgical procedures. This case report documents a retrospective analysis of a surgical technique. The described technique is also a complement of a well-described technique for horizontal augmentation procedures. Therefore, the case report was exempted from the institutional review board approval process. A healthy 26-year-old woman had aplasia of multiple teeth in the upper and lower jaws. In addition to extensive bilaterally maxillary sinus and transversal ridge defects, a severe vertical bone defect was present in the mandible in the region of the left lower first molar and second bicuspid (Fig 1).
line angle of the left lower second molar to the ascending ramus. This relieving incision also was the access for the donor site of the bone graft. A full-thickness flap was elevated and, for tension-free wound closure, the periosteum was slit basally to the flap right at the beginning of surgery to prevent bleeding by the time of membrane placement at the end of the procedure. The bony defect was measured using a periodontal probe to determine the size of the defect, and the bone shell and the cortical plate, respectively, were perforated with a bur for better angiogenesis of the graft. In addition, mesial and distal rests were created for a precise fit of the shell.
SURGICAL PLANNING
Backward planning using a wax-up and a mock-up was performed for prosthodontic reconstruction. The result was transformed to a radio-opaque surgical template, and cone-beam computer tomography (Model 9500 CBCT, Carestream Dental; Kodak, Rochester, NY) was performed for surgical planning. The patient was instructed to take amoxicillin 1,000 mg 3 times a day, ibuprofen 400 mg, and Decortin (Merck KGaA, Darmstadt, Germany) 50 mg (to prevent inflammation and swelling) 1 hour before ridge augmentation. Ibuprofen was continued for 3 days at 3 times a day and the antibiotics for 6 days at 3 times a day after augmentation. Immediately before surgery, the patient rinsed her mouth with a 0.2% chlorhexidine solution for 3 minutes.
GRAFT HARVESTING
The augmented bone was harvested at the left ascending ramus of the mandible. With the help of an ultrasonic knife (Piezosurgery; Mectron, Cologne, Germany), a corticocancellous bone block was obtained. The harvested bone block had a thickness of approximately 3 mm. In a bone mill (Bull Bone Mill; Mondeal, M€ uhlheim an der Donau, Germany), the block was decreased to a thickness of less than 1 mm and used as the shell. The milled bone chips were mixed with autogenous blood and used as particulate bone for the augmentation. The donor site was filled with a collagen fleece (Resorba, Nueremberg, Germany) and closed with interrupted sutures (nylon, 5-0; Resorba). GRAFT PLACEMENT
GRAFT SITE PREPARATION
A midcrestal incision in the region of the left lower first molar and second bicuspid was followed by a sulcular incision along the left lower second molar and first bicuspid, with a relieving incision at the distal
The bone shell was trimmed with a cutting wheel, adjusted with a round bur, and anchored in the residual bone with 2 titanium microscrews, 1.3 mm in diameter 9 mm in the region of the left lower second bicuspid and 1.0 mm in diameter 7 mm in the region
288
VERTICAL RIDGE AUGMENTATION
FIGURE 2. Lateral view of the fixated bone shell shows the huge vertical defect.
FIGURE 4. Postsurgical radiograph shows vertical augmentation and microscrews (detail of a Panorex radiograph).
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
of the left lower first molar (Q-Bone-Grafting Set; Trinon, Karlsruhe, Germany; Fig 2). The vertical space between the shell and the alveolar crest was filled with a mixture of milled bone chips and autogenous blood (Fig 3). The bone graft was covered with a resorbable collagen membrane (BioGide; Geistlich, Wolhusen, Switzerland) and the wound was closed with a coronally advanced flap. To secure the wound margins, deep horizontal mattress sutures (Gore-Tex, 6-0; WL Gore, Flagstaff, AZ) were applied for wound fixation and interrupted sutures (Mopylen, 6-0; Resorba) were applied for wound adaptation. To document the surgical result, a Panorex radiograph (Orthophos 3D; Sirona, Bensheim, Germany) was obtained just after surgery (Fig 4).
grafted site were removed on day 10 after surgery, and the mattress sutures were removed on day 14 after surgery. After 2 weeks, the wound was primarily closed without any signs of inflammation. The patient was provided with a removable dental prosthesis (RDP). Particular attention was paid so that no contact or pressure from the prosthesis was transferred to the gingiva or the graft.
WOUND HEALING
Wound healing showed no complications. The single sutures on the retromolar donor site and on the
FIGURE 3. Bone chips mixed with autogenous blood fill the gap between the shell and the residual bone. Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
IMPLANT PLACEMENT
The patient was instructed to take amoxicillin 1,000 mg 3 times a day and ibuprofen 400 mg 1 hour before implant placement. Ibuprofen was continued for 3 days at 3 times a day and the antibiotics for 6 days at 3 times a day after surgery. Mouth disinfection was performed as described earlier. The integration period of the bone graft was 6 months 24 days. Because of the previous massive augmentation and the coronally advanced flap for wound closure, the displacement of the mucogingival junction had to be replaced during implant placement. Therefore, an incision about 1 mm deep was performed at the mucogingival junction, and a splitthickness flap was sharply dissected for a plasty of the vestibule.17 Then, a midcrestal incision was conducted to cut the periosteum. The periosteum was reflected buccally and a full-thickness flap was reflected lingually to expose the augmented bone (Fig 5). After removal of the 2 microscrews, the implants in the region of the left lower first molar (4.3 mm in diameter 7 mm; Conelog; Camlog Biotechnologies, Wimsheim, Germany) and the region of the left lower second bicuspid (3.8 mm in diameter 9 mm; Screwline Promote Plus; Camlog Biotechnologies) were placed with a positioning guide at the planned positions. Healing abutments were screwed into the 2 implants for open healing. The buccally reflected periosteum
289
STIMMELMAYR ET AL
FIGURE 5. Re-entry 5 months after augmentation shows ideal consolidation of the bone graft and reconstruction of the alveolar crest. Note the formation of a thin cortical plate. Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
and the lingually reflected full-thickness flap were adapted around the healing abutments with a combination of mattress and interrupted sutures (Mopylen 6-0; Resorba), for which all knots were placed on the lingual side. A free gingival graft, taken from the hard palate, was placed and secured with interrupted sutures (Mopylen, 6-0; Resorba) on the periosteum to increase the width of the keratinized gingiva.17 The palatal donor site was covered with a palatal stent (1.5 mm; Erkodent, Pfalzgrafenweiler, Germany) for 5 days to facilitate wound healing. To document the implant positions, a postsurgical Panorex radiograph (Orthophos 3D) was obtained (Fig 6). The RDP was reduced on the basal side to avoid any contact between the RDP and the healing abutments during osseointegration of the implants. Wound healing was uneventful. The single sutures were removed on day 8, and the mattress sutures were removed on day 14 after implant placement (Fig 7).
FIGURE 7. Surgical result after vertical ridge augmentation, implant placement in the region of the left lower first molar and second bicuspid, and extension of the keratinized gingiva with a free gingival graft. Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
Owing to the loss of vertical dimension because of the multiple aplasias, the implants were restored with long-term provisional for progressive bone loading and to test the new vertical dimension. A radiograph after a loading period of 6 months showed biological bone resorption around the implants and stable vertical bone regeneration. A potential small bone sequestration was noticeable distal to the implant in the region of the left lower second bicuspid (Fig 8). However, no clinical signs of an inflammation were present. This will be checked at the 12-month recall.
Discussion This case ended with a primary wound closure and uneventful bone healing. Nearly 7 months after the vertical augmentation procedure, the planned implants could be inserted at the proper positions in
FIGURE 6. Postsurgical radiograph shows stabile vertical augmentation and implants (detail of a Panorex radiograph).
FIGURE 8. Six-month follow-up radiograph shows implants restored with a long-term provision for progressive bone loading. A potential small bone sequestration is noticeable distal to the implant in the region of the left lower second bicuspid.
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
Stimmelmayr et al. Vertical Ridge Augmentation. J Oral Maxillofac Surg 2014.
290 a second-stage surgery. In the region of the left lower first molar, slight vertical resorption of the horizontally placed shell was observed. Using the radiographs after the augmentation procedure and before implant placement, the heads of the titanium microscrews served as detectors for the amount of resorption. Because of this minimal vertical resorption, the implant in the region of the left lower first molar was placed slightly deeper. Placing a thick cortical bone block as an onlay graft can lead to sequestration of the block because of poor or missing revascularization and revitalization. This was noted in some cases several years after the augmentation procedure. With the help of the shell technique described earlier, the regeneration of vital bone was observed.13-16 Filling the vertical gap with particulate bone has 2 advantages. First, it is easier to fill the gap with bone chips than to trim a bone block exactly to a form that fits between the shell and the residual bone. Second, angiogenesis of bone chips seems favorable compared with a thick cortical bone block, which represents a biological benefit. Shells thinner than 1 mm provide the vertical dimension of the graft and prevent the resorption of particulate bone chips. Perforations of the cortical plate of the residual bone allow a blood supply to and revascularization of the bone chips. However, there is no evidence that these perforations lead to better bone healing. In most animal studies, no perforations were made. In a personal comment, Prof Dr Frank Schwarz (personal communication, August 21, 2010) mentioned that perforations can never be performed similarly and therefore are not performed in studies comparing different augmentation procedures. He suggested always perforating the cortical bone plate in clinical situations for better angiogenesis. In the present case, natural bleeding of the implant bed during implant placement suggested vital bone cells. The need for circumferential keratinized gingiva around implants has been a controversial issue for years. Evidence of bone loss is still pending, however, and the available data clearly suggest that implants should be surrounded by keratinized gingiva wherever possible. This is particularly difficult in the posterior mandible after long-standing tooth loss or disuse atrophy. As shown in this case report, hard tissue augmentation requires primary wound closure and leads to vestibular flattening and displacement of the mucogingival line. Therefore, a secondary soft tissue grafting was conducted simultaneously with implant placement. This technique offers long-term stability of the keratinized gingiva around dental implants.17 Harvesting a bone graft from the iliac crest for vertical ridge augmentation is a major surgical procedure compared with the modified shell technique described in
VERTICAL RIDGE AUGMENTATION
the present study.7 The donor site is intraoral and often in the same quadrant as the region where augmentation is required. Therefore, in many cases, especially for augmentation of defects in the lower jaw, only 1 wound is opened for augmentation and for harvesting the shell and bone chips. Adjusting the thickness of the bone shell with the bone mill is convenient and uncomplicated and allows simultaneous retrieval of the bone chips. Also, the technique is relatively straightforward, as shown previously for horizontal hard tissue augmentation.14 Future clinical studies are needed to evaluate the amount of vertical bone regeneration quantitatively and histologically. A case series with data acquisition of 19 cases is under way. In this case report, the vertical reconstruction of the alveolar crest was conducted using the modified shell technique. This has a major influence for long-term stability of an implant-supported dental prosthesis. The potential of only 1 donor site might help to decrease postsurgical morbidity and complication rates. The vertical shell technique described offers 1) possible vertical bone reconstruction, 2) intraoral harvesting of autogenous bone for major vertical augmentation procedures, 3) regeneration of vital bone, and 4) proper conditions for implant placement.
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STIMMELMAYR ET AL 12. Sbordone C, Toti P, Guidetti F, et al: Volume changes of iliac crest autogenous bone grafts after vertical and horizontal alveolar ridge augmentation of atrophic maxillas and mandibles: A 6-year computerized tomographic follow-up. J Oral Maxillofac Surg 70:2559, 2012 13. Khoury F, Ponte A: The 3-dimensional reconstruction of the alveolar crest with mandibular bone block graft: A clinical study. Int J Oral Maxillofac Implants 19:795, 2004 14. Stimmelmayr M, Guth JF, Schlee M, et al: Use of a modified shell technique for three-dimensional bone grafting: Description of a technique. Aust Dent J 57:93, 2012
291 15. Khoury F, Khoury C: Mandibular bone block grafts; instrumentation, harvesting technique and application. J Par Impl Orale 25: 15, 2006 16. Khoury F, Antoun H, Missika P: Bone Augmentation in Oral Implantology. London, UK, Quintessence, 2007 17. Stimmelmayr M, Stangl M, Edelhoff D, et al: Clinical prospective study of a modified technique to extend the keratinized gingiva around implants in combination with ridge augmentation: One-year results. Int J Oral Maxillofac Implants 26: 1094, 2011