Advanced surgery V- Vertical Augmentation

rhBMP with wire mesh, sonic weld, block grafts, titanium reinforced membranes. Nerve transposition

Advanced Surgery and Implant Literature Review

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Implant success/survival. Complications

Proussaefs P, Lozada J, Kleinman A, Rohrer MD. The use of ramus autogenous block grafts for vertical alveolar ridge augmentation and implant placement: a pilot study. Int J Oral Maxillofac Implants. 2002 Mar-Apr;17(2):238-48
Proussaefs P, Lozada J. The use of intraorally harvested autogenous block grafts for vertical alveolar ridge augmentation: a human study. Int J Periodontics Restorative Dent. 2005 Aug;25(4):351-63.
Merli M, Lombardini F, Esposito M. Vertical ridge augmentation with autogenous bone grafts 3 years after loading: resorbable barriers versus titanium-reinforced barriers. A randomized controlled clinical trial. Int J Oral Maxillofac Implants. 2010 Jul-Aug;25(4):801-7.
Urban IA, Lozada JL, Jovanovic SA, Nagursky H, Nagy K. Vertical ridge augmentation with titanium-reinforced, dense-PTFE membranes and a combination of particulated autogenous bone and anorganic bovine bone-derived mineral: a prospective case series in 19 patients. Int J Oral Maxillofac Implants. 2014 Jan-Feb;29(1):185-93
Guze KA, Arguello E, Kim D, Nevins M, Karimbux NY. Growth factor-mediated vertical mandibular ridge augmentation: a case report. Int J Periodontics Restorative Dent. 2013 Sep-Oct;33(5):611-7.
Louis PJ, Gutta R, Said-Al-Naief N, Bartolucci AA. Reconstruction of the maxilla and mandible with particulate bone graft and titanium mesh for implant placement. J Oral Maxillofac Surg. 2008 Feb;66(2):235-45.
Louis PJ. Vertical ridge augmentation using titanium mesh. Oral Maxillofac Surg Clin North Am. 2010 Aug;22(3):353-68
Todisco M. Early loading of implants in vertically augmented bone with non-resorbable membranes and deproteinised anorganic bovine bone. An uncontrolled prospective cohort study. Eur J Oral Implantol. 2010 Spring;3(1):47-58.
Lorean A, Kablan F, et al. Inferior alveolar nerve transposition and reposition for dental implant placement in edentulous or partially edentulous mandibles: a multicenter retrospective study. Int J Oral Maxillofac Surg. 2013 May;42(5):656-9.
Friberg, G et al: Inferior Alveolar Nerve Transposition in Combination with Branemark Implant Treatment. I nt. J Perio Rest Dent 12:441-450, 1992
Proussaefs P. Inferior alveolar nerve transposing in a situation with minimal bone height: a clinical report. J Oral Implantol. 2005;31(4):180-5.
Chiapasco M et al: Vertical distraction osteogenesis of edentulous ridges for improvement of oral implant positioning: A clinical report of preliminary results. Int J Oral Maxillofac Implants 16:43-51,2001
Spagnoli DB, Marx RE. Dental implants and the use of rhBMP-2. Dent Clin North Am. 2011 Oct;55(4):883-907
Simion M et al: Long-term evaluation of osseointegrated implants inserted at the time or after vertical ridge augmentation. A retrospective study on 123 implants with 1-5 year follow-up. Clin Oral Implants Res: 12:35-45, 2001
Urban IA, Jovanovic SA, Lozada JL. Vertical ridge augmentation using guided bone regeneration (GBR) in three clinical scenarios prior to implant placement: a retrospective study of 35 patients 12 to 72 months after loading. Int J Oral Maxillofac Implants. 2009 May-Jun;24(3):502-10.
Clementini M, Morlupi A, Canullo L, Agrestini C, Barlattani A. Success rate of dental implants inserted in horizontal and vertical guided bone regenerated areas: a systematic review. Int J Oral Maxillofac Surg. 2012 Jul;41(7):847-52.

Abstracts:

Authors: Proussaefs P, Lozada J, Kleinman A, Rohrer MD.

Title: The use of ramus autogenous block grafts for vertical alveolar ridge augmentation and implant placement:

Source: Int J Oral Maxillofac Implants. 2002 Mar-Apr;17(2):238-48

Type: a pilot study.

Keywords: block graft, vertical ridge augmentation

Purpose:This study presents a clinical, radiographic, laboratory, and histologic/histomorphometric analysis of the use of mandibular ramus block autografts for vertical alveolar ridge augmentation and implant placement.

Materials and Methods: pts (2 men and 6 women, mean age 65) participated in this study.Autogenous block autografts were fixed at the recipient site with fixation screws while a mixture of autogenous bone marrow and inorganic bovine material (Bio-Oss) was used at the periphery. All grafts appeared well incorporated at the recipient site during re-entry surgery.

Results:

1. - Radiographic measurements revealed an average of 6.12 mm vertical ridge augmentation 1 month after surgery and 5.12 mm 4 to 6 months after surgery.
  - Laboratory volumetric measurements revealed an average of 0.91 mL alveolar ridge augmentation 1 month after surgery and 0.75 mL 6 months postoperatively. Linear laboratory measurements revealed 6.12 mm of vertical ridge augmentation 1 month postoperatively and 4.37 mm 4 to 6 months after surgery.
  - Histologic evaluation indicated signs of active remodeling in all the specimens.
  - Histomorphometric analysis of the peripheral particulate bone indicated bone present at 34.33% of the grafted area, while 42.17% of the area was occupied by fibrous tissue and 23.50% by residual Bio-Oss particles.

Conclusion:

1. 1. Mandibular block autografts can maintain their vitality when used for vertical alveolar ridge augmentation.
  2. An average of 5.12 mm of vertical ridge augmentation was achieved and 17% resorption was seen 4 to 6 months after bone grafting.
  3. Late graft exposure may not necessarily result in graft necrosis, while early exposure may result in compromised healing and partial graft necrosis.
  4. Inorganic bovine mineral (Bio-Oss) can be used at the periphery of the block graft when mixed with autogenous bone marrow. This mixture resulted in an average of 34.33% bone formation in this series.

Topic: Vertical Augmentation

Authors:Proussaefs P, Lozada J

Tittle: The use of intraorally harvested autogenous block grafts for vertical alveolar ridge augmentation: a human study.

Source: Int J Periodontics Restorative Dent. 2005 Aug;25(4):351-63.

Type: Clinical study

Keywords: Vertical Augmentation

Purpose: This study presents a clinical, radiographic, laboratory, and histologic/histomorphometric analysis of the use of mandibular block autografts for vertical alveolar ridge augmentation.

Methods: 12 patients received autogenous block autografts. These were fixated at the recipient sites with screws, and a mixture of autogenous bone marrow and inorganic bovine mineral (Bio-Oss) was used at the periphery.

Results:

1. - At re-entry surgery, all the grafts appeared well incorporated at the recipient sites.
  - Radiographic measurements revealed an average of 5.75 ± 1.29 mm vertical ridge augmentation at 1 month after surgery and 4.75 ± 1.29 mm at 4 to 6 months after surgery. This indicated 17.4% resorption.
  - Histologic evaluation of the block autografts indicated signs of active remodeling activity in 10 of the 12 specimens.
  - In one case the block graft became exposed and infected, and in another case the block autograft became dislodged during implant placement surgery.
  - Histomorphometric analysis of the peripheral mixture of particulate results in an aver- age of 33.99% bone formation, while 42.43% of the area was occupied by fibrous tissue and 23.89% was made up of residual Bio-Oss particles. Residual Bio-Oss particles were in tight contact with newly formed bone along 58.57% of their perimeter.

Conclusions: Mandibular block autografts can maintain their vitality when used for vertical alveolar ridge augmentation.

Topic: Resorbable barrier vs titanium-reinforced barriers
Authors: Merli M, Lombardini F, Esposito M.

Title: Vertical ridge augmentation with autogenous bone grafts 3 years after loading: resorbable barriers versus titanium-reinforced barriers. A randomized controlled clinical trial.

Source: Int J Oral Maxillofac Implants. 2010 Jul-Aug;25(4):801-7.

Type: Clinical study

Keywords: dental implants, guided bone regeneration, peri-implant bone levels, vertical augmentation

Purpose: To compare vertical bone regeneration at implant placement results using resorbable collagen membranes versus non-resortable titanium reinforced membranes.

Method: 22 patients requiring vertical bone augmentation were split into two groups, resorbable and non-resorbable membranes. Prosthetic and implant failures, complications, the amount of vertically regenerated bone, and peri-implant marginal bone levels were recorded by independent and blind assessors. Follow-up time ranged from provisional loading to 3 years after loading.

Result: No prosthetic or implant failures or complications occurred after loading. There was NSSD in bone loss between the two groups at 1 or 3 years. Both groups had gradually lost a SS amount of peri-implant bone at 1 and 3 years. At year 3, patients treated with resorbable membranes lost a mean of 0.55 mm of bone and those treated with non-resorbable membranes lost 0.53 mm.

Conclusion: Vertically regenerated bone can be successfully maintained after functional loading at 3 year follow up. There is no difference between the resorbable and non-resorbable barriers for this application.

Topic: Vertical ridge augmentation

Authors: Urban IA, Lozada JL, Jovanovic SA, Nagursky H, Nagy K.

Title:Vertical ridge augmentation with titanium-reinforced, dense-PTFE membranes and a combination of particulated autogenous bone and anorganic bovine bone-derived mineral: a prospective case series in 19 patients

Source:Int J Oral Maxillofac Implants. 2014 Jan-Feb;29(1):185-93

Type: Case Series

Keywords:anorganic bovine bone-derived mineral, case series, guided bone regeneration, nonresorbable membrane, verticial augmentation.

Purpose: This prospective case series evaluated the use of a new titanium-reinforced nonresorbable membrane (high-density polytetrafluoroethylene), in combination with a mixture of anorganic bovine bone-derived mineral (ABBM) and autogenous particulated bone, for vertical augmentation of deficient alveolar ridges.

Method: A mixture of ABBM and autogenous particulated bone was used for vertical ridge augmentation and covered with a new titanium-reinforced nonresorbable membrane. Ridge measurements were obtained before and after the procedure, complications were recorded, and biopsy specimens were taken for histologic examination.

Results: Twenty vertical ridge augmentation procedures were carried out in 19 patients. All treated defect sites exhibited excellent bone formation, with an average bone gain of 5.45 mm (standard deviation 1.93 mm). The healing period was uneventful, and no complications were observed. Eight specimens were examined histologically; on average, autogenous or regenerated bone represented 36.6% of the specimens, ABBM 16.6%, and marrow space 46.8%. No inflammatory responses or foreign-body reactions were noted in the specimens.

Conclusion: The treatment of vertically deficient alveolar ridges with guided bone regeneration using a mixture of autogenous bone and ABBM and a new titanium-reinforced nonresorbable membrane can be considered successful.

Topic:Ridge augmentation with growth factor

Title: Growth Factor Mediated Vertical Mandibular Ridge Augmentation: A Case report

Author: Guze, K et al

Source: International journal of periodontics and restorative dentistry 2013: 33, 5 611-620

Type: Case report

Keywords: vertical ridge augmentation, growth factors, guided bone regeneration

Purpose: to demonstrate a proof of principle case report utilizing a composite freeze-dried bone allograft and recombinant human platelet-derived growth factor BB in conjunction with an overlying titanium mesh to regenerate well-vasculatized bone in significant posterior mandibular ridge defect prior to implant placement.

Methods and Materials: 44 year-old woman with left sided unilateral partially endentulous, moderately atrophic mandible with vertical deficiency. Surgery: FTF was reflected to expose ridge, a flexible 0.1mm thick titanium mesh was shaped and refined for graft site. Intramarrow penetrations completed. FDBA was saturated in rhPDGF-BB for 15 minutes and then carefully placed o permit optimal vertical and horizontal bone regeneration to occur. Mesh was then placed over graft and secured with screws. The flaps were closed with no reported tension. Patient was examined at 1, 2, 4, 8, 12, 24 weeks post op. CT scan was taken at 6 months and then a re-entry surgery was done at the same time to place implants. During implant placement bone cores were taken for histology.

Results: During the 24-week follow up no complications were seen. Direct linear measurements revealed an alveolar ridge width of 8mm and an approximately 10mm increase in ridge height. Histo: no native bone was present in the core samples. A number of residual graft particles seen surrounded by newly formed bone.

Conclusion: Within the boundaries of this study, the combination of FDBA, rhPDGF-BB, and titanium mesh may provide a minimally invasive, alternative treatment modality for moderate/severely resorbed alveolar ridge.

Topic: Vertical Augmentation

Authors: Louis PJ, Gutta R, Said-Al-Naief N, Bartolucci AA.

Title: Reconstruction of the maxilla and mandible with particulate bone graft and titanium mesh for implant placement

Source: J Oral Maxillofac Surg. 2008 Feb;66(2):235-45.

Type: Retrospective Study

Keywords: titanium mesh, particulate bone graft, ridge augmentation

PURPOSE: The purpose of the study was to evaluate the magnitude of ridge augmentation with titanium mesh, overall graft success, anatomic location of ridge defects and their relationship to mesh exposure.

MATERIALS AND METHODS: This retrospective study evaluated 44 patients who received mandibular or maxillary reconstruction with autogenous particulate bone graft and titanium mesh for the purpose of implant placement. Autogenous bone graft was harvested from the iliac crest, tibia, and mandibular symphysis. A total of 45 sites were included in the study. Average augmentation bone heights were measured and compared. Statistical analysis was done with ANOVA and Student’s t test. Histomorphometric analysis was performed on the soft tissue specimen found between the mesh and the bone graft.

RESULTS:Twenty-nine sites underwent mandibular reconstruction and 16 underwent maxillary reconstruction. The mean augmentation in partial maxillary defects was 11.33 +/- 1.56 mm, and in complete maxillary augmentation, the height achieved was 14.3 +/- 1.39 mm. In the mandible, mean increase in height for partial defects was 14 +/- 1.42 mm and for complete augmentation it was 13.71 +/- 1.14 mm. The mean augmentation for all sites was 13.7 mm (12.8 mm in the maxilla and 13.9 mm in the mandible). A total of 82 implants were placed in the maxilla and 92 implants were placed in the mandible. In the maxillary group, 7 sites had exposure of the titanium mesh and 16 sites were exposed in the mandible. The success of the bone grafting procedure was 97.72%.

CONCLUSIONS: Porous titanium mesh is a reliable containment system used for reconstruction of the maxilla and the mandible. This material tolerates exposure very well and gives predictable results.

Topic:Vertical ridge augmentation using titanium mesh

Authors: Louis PJ

Title:Vertical ridge augmentation using titanium mesh.

Source: Oral Maxillofac Surg Clin North Am. 2010 Aug;22(3):353-68, v. doi: 10.1016/j.coms.2010.04.005

Type: clinical

Keywords: vertical ridge augmentation; titanium mesh; reconstruction.

Purpose:All of techniques have advantages and disadvantages. This article focuses on augmentation procedures using titanium mesh, which acts as a barrier and physical support of the soft tissue over the bone graft.
Methods:management of edentulous maxilla: full thickness flap; 5 mm below the depth of the maxillary vestibule extending posterior. Superior extent: just below the infraorbital nerve. Sinus lift performed simultaneously. Precontoured titanium mesh is chosen based on desired augmentation. Further contouring if needed. Titanium mesh trays are filled with bone graft material and placed in position and secured with at least 2 screws in facial and at least one in palate. Then the wound can be closed in layers. Titanium mesh can be used on partially edentulous maxilla with a modification of this method.

Atrophic mandible can be augmented with titanium mesh with an intraoral and extraoral approach. In extra oral approach, the incision is made along the submental crease, sharply down to the inferior border of mandible where a subperiosteal dissection is performed. Using this approach, the mental nerves can be easily identified.

Results:

Advantages of titanium mesh:

1. - Height and width of augmentation, ideal shape.
  - Nonresorbable and rigid: The rigidity allows for shape maintenance, which is important when attempting to extend the bony envelope. The soft tissue is placed under tension during an augmentation procedure, thus causing a flattening or deforming of nonrigid membranes and the associated graft. Titanium mesh is rigid and will maintain its shape.
  - Biocompatible: can be place subperiosteally.
  - Vestibuloplasty at the time of mesh removal

Disadvantages:

1. - Tendency to become exposed during healing. (although, the risk of infection remains low). The use of vestibular incisions may decrease the risk of exposure.
  - Additional contouring needed.

Conclusion: the use of titanium mesh and bone graft is a successful technique in reconstruction of atrophic mandible and maxilla. The main advantage of is the rigidity of the material which prevents collapse and flattening of the graft during ridge augmentation.

Topic:Early implant loading

Author:Todisco M.

Title: Early loading of implants in vertically augmented bone with non-resorbable membranes and deproteinised anorganic bovine bone. An uncontrolled prospective cohort study

Source:Eur J Oral Implantol. 2010 Spring;3(1):47-58.

Type:Prospective cohort study

Keywords:bone regeneration; bone substitute; implants; membrane

Purpose: To evaluate the clinical and histological outcomes 1 year after loading of early-loaded implants placed in vertically augmented bone using deproteinised bovine bone (Bio-Oss) and a titanium-reinforced membrane (Gore-Tex)Results:A total of 23 out of 25 sties healed uneventfully. Two sites showed ehe surgery was repeated with success 2 months later. The mean vertical bone gain after GBR was 5.2mm. Histology of five samples showed a total percentage of xenograft and new bone of 52.6%, with dispersed graft particles surrounded by layers of bone. The density of regenerated tissue at drilling was found to be slightly less than the native bone. All implants were stable after 1 year of function (100% survival rate). SS peri-implant bone loss (0.95mm) was observed radiographically from baseline to the 1-year follow-up.

Conclusion: This study shows that by using deproteinised bovine bone and non-resorbable titanium-reinforced membrane, vertical bone gain can be obtained and implants can be loaded after 30 days. The vertical regenerated tissue exhibited good stability over 1 year of implant function.

Criticism: No control was evaluated in this study. The process of standardized radiographs seems to have a lot of room for error.

Topic: Inferior alveolar nerve transposition

Authors: Lorean A, Kablan F, et al.

Title: Inferior alveolar nerve transposition and reposition for dental implant placement in edentulous or partially edentulous mandibles: a multicenter retrospective study

Source: Int J Oral Maxillofac Surg. 2013 May;42(5):656-9.

Type: Retrospective Study

Keywords: bone width; success; survival; alveolar bone; dental implantation; mandible

Purpose: To evaluate the success and complications following IAN transposition/reposition for dental implant placement in edentulous or partially edentulous mandibles.

Methods: IAN lateralization: Nerve is exposed and traction is used to deflect it laterally while implants are placed. IAN transposition: Corticotomy is done about the mental foramen and the incisive nerve is transected, such that the mental foramen can be positioned more posteriorly. At follow up visits, nerve function was assessed with a 2-point discrimination test, Von Frey test (nociceptor stimulation), and pin prick with a sharp instrument. Findings were recorded.

Results: 68 repositions and 11 transpositions were performed in 57 patients (46 females and 11 males, avg. age 47). 3 patients reported smoking. 232 implants were placed. Average follow up time was 20 months. One implant was lost during the follow up period. 4 patients reported neural disturbances (1 transposition, 3 repositions) following surgery for 1-6 months. Some patients reported short-term disturbances (0-4 weeks). No symptoms were permanent.

Conclusion: IAN transposition and reposition are useful adjunct techniques for the management of severely atrophic posterior edentulous/partially edentulous mandibles, with very low risk of neural dysfunction.

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Topic: Inferior Alveolar Nerve Transposition

Authors: Friberg, G et al
Title: Inferior Alveolar Nerve Transposition in Combination with Branemark Implant Treatment

Source:I nt. J Perio Rest Dent 12:441-450, 1992

Type: Technique article

Keywords

Purpose: to present the surgical protocol for the inferior alveolar nerve transposition in combination with implant placement and evaluates the short-term outcome of the first procedures with this technique as used at the Branemark Clinic.

Method:ten nerve transpositions performed in one man and 6 women with mean age 60 years (range 41 to 82 years). Three of the treated jaws received three implants each, while the other seven received 2 implants each. In total, 23 implants were placed from Dec, 1990 to Dec, 1991. All patients were edentulous posterior to the mandibular canine or first bicuspid and had poor vertical bone as radiographs had shown. Patients were informed about the transposition procedure and possible long-term paresthesia/anesthesia. The patients were assessed postoperatively for pain, paresthesia/anesthesia, and/or other complications after 1,4 and 8 weeks after surgery, at abutment connection and after 6 months.

Results:Primary soft tissue healing was uneventful in all patients. However, after 7 weeks, an infection similar to osteomyelitis developed in one patient and the source was a necrotic canine close to the implant. This was managed by antibiotics which failed and explorative surgery was carried on 4 weeks later. 2 implants had to be removed along with two bone sequestra. Healing was normal and with minor sins of hypoesthesia. Complete bone regeneration of the defects was seen in all patients along with distal position of the foramen. Fixed partial dentures were connected and were in function for 1 to 12 months.

Conclusion:Strict patient selection criteria are necessary for the transposition of the inferior alveolar nerve together with implant placement. This can be beneficial for reconstructing severely resorbed edentulous posterior mandibles.

Topic: Inferior alveolar nerve transposing

Authors: Proussaefs P.

Title:Inferior alveolar nerve transposing in a situation with minimal bone height: A clinical report

Source: Journal of Oral Implantology: 2005; 31(4): 180-185.

Type: Clinical Report

Keywords:Nerve transposing, alveolar resorption, bone grafting, inferior alveolar nerve repositioning, neurosensory disturbance

Purpose:To describe treatment of a patient where minimal crestal bone was observed coronal to the canal of the Inferior alveolar nerve (IAN). For this purpose, an autogenous bone graft was placed around the implants and covered with a collagen membrane.

Materials and methods:

56-year-old woman with edentulism and extensive resorption at area of teeth 18-20, 30 and 31. Computerized tomography scan indicated that the IAN was 1 to 2 mm below the crest of residual alveolar ridge. Around mental foramen, the canal of the IAN was at the same level with the crest. A crestal incision was performed; full thickness labial and lingual flaps were reflected. Al lateral access window (LAW) was performed. Two horizontal and two vertical osteotomies were performed. The IAN was retracted. With an acrylic resin surgical stent, implants were placed in teeth 18-20, 30 and 31. The autogenous bone from the LAW was particulate and placed around the implants. Resorbable collagen membrane was placed above the graft material. Flaps sutured. Second stage surgery after 6 months of implant placement. Implants were osseointegrated and restored with cement retained metal ceramic restorations. Three years post loading; there was minimal marginal bone loss. The patient reported transient hypesthesia that lasted for 3 months but no further symptoms of neurosensory disturbance were observed.

Discussion: Previous studies suggest that a minimum of 6 to 8 mm of bone is needed above the canal of the IAN to provide implant stability, in most cases this means vertical ridge augmentation and implant placement simultaneously (1-stage bone grafting). In this case, application of this technique was not feasible because of the excessive resorption.

Mandibular block autografts: used for vertical ridge augmentation/ 5 mm, 6 months after graft

1. - In this case 10 mm vertical ridge would be needed. 2-stage bone grafting offers inadequate results in severely resorbed cases.

In this case, autogenous bone was particulated and placed around implants. Particulate graft was used to avoid mechanical trauma to the IAN from fixation process of the block.

Regarding transposing IAN, sensory disturbance should be considered and explained to the patient.

Conclusion: In a situation with minimal bone height above IAN, implant placement and TIAN may be considered in conjunction with autogenous particulated bone graft.

Topic: INTRAORAL VERTICAL DISTRACTION OSTEOGENESIS, RIDGE AUGMENTATION

Authors: Chiapasco

Title: Vertical Distraction Osteogenesis of Edentulous Ridges for Improvement of Oral Implant Positioning: A Clinical Report of Preliminary Results

Source: IJOMI

Type: clinical report

Rating: good results,Low number of paitents, low level evidence

Keywords: dental implants, distraction osteogenesis, implant-supported prosthesis, preprosthetic oral surgical procedures

Background: Vertically deficient edentulous ridges remain a challenge for implant placement. Vertical guided regeneration (GBR) with semipermeable barriers often yield unpredictable bone gain, membranes are at risk for exposure and infection, and autogenous grafts are associated with increased morbidity and are prone to unpredictable gain. Distraction osteogenesis was originally created for orthopedic purposes and was later applied to the maxillofacial region to correct severe malformations, sleep apnea and dento-facial manifestations of various syndromes. More recently it has been being used to improve bone volume to facilitate eventual implant placement.

Purpose: To present the experience of the authors in treating vertical defects in edentulous ridges by means of intraoral vertical distraction osteogenesis followed by implant placement in the distracted areas.

Materials and Methods: 8 patients w defects from various etiologies with minimum 5mm width of ridge but height that was deficient for implant placement and who didn’t present with common relative contraindications of implant placement were included. Intraoral photographs and panoramic radiographs taken intraoperatively, at time of distractor removal. and implant placement, 4 patients evaluated with CT.

The procedure was started with an intraoral incision in the buccal vestibule, without lateral releasing incisions. Careful subperiosteal dissection was per- formed to obtain adequate visibility of the underlying bone, but to preserve as much as possible the lingual or palatal pedicle after the osteotomy was performed. Preplating and adjustment of the intra- oral distractor was performed before starting the osteotomy. With an oscillating saw or a fissure bur, under irrigation with sterile saline, the bone seg- ment to be vertically distracted was completely separated from the basal bone. The vertical osteotomies were enlarged to allow movement of the segment with no interference. Once the osteotomy was completed, the intraoral distractor was fixed to both the basal bone and the ostetomized segment with 1.5-mm titanium miniscrews (Gebruder Mar- tin GmbH). The osteotomized segment to be distracted was immediately moved by activating the distractor to check the direction of distraction and freedom of movement. Finally, the osteotomized segment was repositioned at its initial position and the surgical access was sutured with 4/0 silk sutures. Healing by secondary intention is unavoidable, because a portion of the distractor must pass through the incision to activate the distractor. All patients received antibiotics and non- steroidal analgesics postoperatively. A soft diet for 2 weeks postoperatively and appropriate oral hygiene with 0.2% chlorhexidine mouthwash were pre- scribed. After a 7-day waiting period for closure of the surgical wound, sutures were removed and the activation was started. A distraction of 1 mm per day (subdivided into 2 activations of 0.5 mm every 12 hours) was performed with a specific device until the desired amount of distraction was obtained. The distractor was then maintained in position for 2 to 3 months to obtain maturation of the neocallus formed between the basal bone and the distracted segment. Once consolidation of the distracted seg- ments was obtained, the distractor was removed and endosseous implants were placed following the indi- cations of surgical templates.

A total of 26 titanium screw-shaped endosseous implants were placed in the distracted segments; 4 patients received 15 Brånemark System implants (Nobel Biocare, Göteborg, Sweden), and 4 patients received 11

screw-type ITI implants (Straumann, Waldenburg, Switzerland). Four to 6 months later, abutments were connected to the implants, and prosthetic treatment was started. Implants were followed with clinical examinations and panoramic radiographs every 6 months. The following parameters were evaluated: (1)vertical bone gain obtained after distraction; (2)radiographic assessment of peri-implant bone resorption mesial and distal to each implant;(3) peri-implant soft tissue parameters (Modified Plaque Index [MPI], Modified Bleeding Index [MBI], and probing depth [PD]); and (4)implant success (Albrekson definition)

Results: Recovery after the distraction procedure was uneventful in all patients treated, and all patients regularly followed the recall program. In all patients, the desired bone gain was reached at the end of distraction, with a mean vertical bone gain of 8.5 mm (range: 6 to 15 mm). In all patients it was possible to place the previously planned number of implants with primary stability and with complete embedding of the implants in both native and newly generated bone at the level of the distracted area. The mean follow-up after initial prosthetic loading was 14 months (range: 12 to 18 months). None of the implants placed were lost during the follow-up period.

Conclusions: distraction osteogenesis provides the following advantages

1. It provides the opportunity to obtain a natural formation of bone between the distracted segment and basal bone in a relatively short time span.

2. It eliminates the need to harvest bone, with con- sequent shortening of operating times and reduction in morbidity.

3. Soft tissues can follow elongation of the underlying bone.

4. Frequently, the procedure can be performed under local anesthesia on an outpatient basis, and postoperative recovery is favorable.

5. The regenerated bone seems to resist resorption. 6. The newly generated bone seems to be able to withstand the functional demands of implant- supported prostheses

Critique: low number of patients, highly skilled surgeons.

Topic: implants and the use of rhBMP-2

Authors: Spagnoli DB, Marx RE

Title: Dental implants and the use of rhBMP-2.

Source: Dent Clin North Am. 2011 Oct;55(4):883-907

Type: Discussion

Keywords: rhBMP-2, Implants

BMPs are members of the transforming growth factor-b superfamily of growth factors.They are key regulators of cellular growth and differentiation, and regulate tissue formation in both developing and mature organisms. Twenty unique BMP ligands have been identified and categorized into subclasses based on amino acid sequence similarity
BMPs exposed within or secreted into a wound affect mesenchymal stem cell (MSC) accumulation through chemotaxis and proliferation. MSCs are influenced by BMP-2 to differentiate either directly into osteoblasts for intramembranous bone development or into chondrocytes, followed by cartilage development and removal for endochondral bone formation.
BMP-induced vascular endothelial growth factor a (VEGF-a) production in osteoblasts plays an important role in the coupling of bone formation and angiogenesis by acting as a chemoattractant for neighboring endothelial cells and stimulating VEGF-a secretion by osteoblasts and endothelial cells.
The only BMP currently available for grafting of maxillofacial implant sites is recombinant human BMP-2 (rhBMP-2)
Histologic specimens were obtained with a trephine technique used at implant placement during the clinical trials. The findings of the histologic assessment showed development of native bone through a de novo intramembranous pathway that repli- cates native bone development. Preosteoblast condensations were observed in asso- ciation with blood vessels, and osteoblasts were observed forming new bone trabeculae through appositional secretion of osteoid and mineralized matrix. Osteo- clast remodeling of the trabeculae was also observed.

Case 1 – complete vertical augmentation of maxilla

Case 2 – continuity defect of the mandible salvaging a deficient-free vascular fibula graft.

Topic: Vertical ridge augmentation

Authors: Simion M

Tittle: Long-term evaluation of osseointegrated implants inserted at the time or after vertical ridge augmentation. A retrospective study on 123 implants with 1-5 year follow-up.

Source: Clin Oral Implants Res: 12:35-45, 2001

Keywords: vertical ridge augmentation

Purpose To evaluate retrospectively, in 4 clinics, 123 implants consecutively inserted in alveolar ridges at the time or after vertical bone augmentation

Methods: 123 Brånemark implants consecutively placed in 53 vertically augmented ridges were evaluated after a period of functional loading varying from 16 to 69 months. The study comprehended 49 partially edentulous patients requiring vertical bone augmentation to improve the crown–implant ratio and the implant support, and/or the esthetic of the final prosthetic reconstruction. The age of the patients ranged from 34 to 66 (median 50.4) years. At the time of the implant surgery, 3 different techniques were used: the implants were allowed to protrude 2 to 7 mm from the  bone level and a titanium reinforced expanded-polytetrafluoroethylene (e-PTFE) membrane was positioned to protect either the blood clot (Group A, 6 patients), or an allograft (Group B, 11 patients), or an autograft (Group C, 32 patients). Follow up at 1 year.

Results:

Only 1 implant failed immediately after the second stage surgery and after 1 month it was substituted with a new implant. All the remaining implants appeared clinically stable, no signs of radiolucency were present at the bone–implant interface, therefore, they could be defined successfully osseointegrated. The radiographic analysis showed stable bone crest levels with a mean bone loss of 1.35 mm for the Group A, of 1.87 mm for the Group B and of 1.71 for the Group C during the period of observation. Only 2 implants demonstrated an increased crestal bone loss of 3.5 mm and 4 mm respectively at the first year examination.

Conclusions: Vertically augmented bone  with GBR techniques respond to implant placement like native, non-regenerated bone.

Topic:Vertical ridge augmentation using guided bone regeneration

Authors: Urban IA, Jovanovic SA, Lozada JL.

Title: Vertical ridge augmentation using guided bone regeneration (GBR) in three clinical scenarios prior to implant placement: a retrospective study of 35 patients 12 to 72 months after loading.

Source: Int J Oral Maxillofac Implants. 2009 May-Jun;24(3):502-10.

Type: Clinical study

Keywords: autogenous bone graft, barrier membranes, guided bone regeneration, sinus augmentation, vertical ridge augmentation

Purpose: To evaluate the results of vertical guided bone regeneration with particulate autogenous bone grafts, determine clinically and radiographically the success and survival rates of implants placed in such surgical sites after prosthetic loading for 12-72 months, and compare defects that were treated simultaneously with sinus augmentation and vertical GBR to other areas of the jaw with vertical GBR only.

Method: 82 implants were placed in 35 patients with 36 vertical bone defects. Patients were divided into three groups: A) single missing teeth, B) multiple missing teeth, C) vertical defects in the posterior maxilla only. All patients were treated with ePTFE membranes and particulated autografts. After removal of the ePTFE membrane, all sites received a collagen membrane.

Result: Mean vertical augmentation at membrane removal was 5.5 mm. At 12 months mean combined crestal remodeling was 1.01 mm and remained stable 6 year follow up. There was NSSD between the three groups in mean marginal bone modeling. Overall implant survival rate was 100% with cumulative success rate of 94.7%.

Conclusion: Vertical augmentation with ePTFE membranes and particulated allografts is safe and predictable. Implant success and survival rates of implants placed in vertically augmented bone are similar to those placed in native bone. Success and failure rates of implants placed into bone regenerated simultaneously with sinus and vertical augmentation techniques compare favorable to those requiring only vertical augmentation.

Topic:Success rate

Authors: Clementini M, Morlupi A, Canullo L, Agrestini C, Barlattani A

Title:Success rate of dental implants inserted in horizontal and vertical guided bone regenerated areas: a systematic review

Source:Int J Oral Maxillofac Surg. 2012 Jul;41(7):847-52.

Type: Review

Keywords:systematic review, ridge augmentation

Purpose:This study assessed the success rate of implants placed in horizontal and vertical guided bone regenerated areas

Method: A systematic review was carried out of all prospective and retrospective studies, involving at least five consecutively treated patients, that analysed the success rate of implants placed simultaneously or as second surgery following ridge augmentation by means of a guided bone regeneration (GBR) technique. Studies reporting only the survival rate of implants and studies with a post-loading follow up less than 6 months were excluded

Results: From 323 potentially relevant studies, 32 full text publications were screened and 8 were identified as fulfilling the inclusion criteria. The success rate of implants placed in GBR augmented ridges ranged from 61.5% to 100%; all studies, apart from three, reported a success rate higher than 90% (range 90–100%). The survival rate of implants, was reported in 6 studies to range from 93.75% to 100%. One study reported a survival rate lower than 99.2%.

Conclusion: The data obtained demonstrated that GBR is a predictable technique that allows the placement of implants in atrophic areas. Despite that, studies with well-defined implant success criteria after a longer follow-up are required.