|Year : 2021 | Volume
| Issue : 1 | Page : 68-72
Autologous chin graft for implant site augmentation revisited
Oliver Jacob1, Manab Kosala2
1 Dental Centre, INHS Kalyani, Visakhapatnam, Andhra Pradesh, India
2 Division of Periodontology, Armed Forces Medical College, Pune, Maharashtra, India
|Date of Submission||10-Dec-2020|
|Date of Decision||07-Feb-2021|
|Date of Acceptance||02-Mar-2021|
|Date of Web Publication||26-Jun-2021|
Dr. Oliver Jacob
Dental Centre, INHS Kalyani, Gandhigram PO, Visakhapatnam - 530 005, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Advanced alveolar bone resorption in the maxillary anterior teeth is a common finding that limits the placement of implants for prosthetic rehabilitation. Autologous bone graft from the mandibular symphysis is one of the oldest techniques in horizontal ridge augmentation techniques for placement of implants in advanced resorption of the alveolar ridge in the maxillary anterior region. This case report revisits the technique carried out using piezoelectric osteotome for harvesting block graft from the mandible to augment the resorbed ridge horizontally to place implant in a young and healthy patient.
Keywords: Autologous block graft, implants, mandibular symphysis graft, ridge augmentation
|How to cite this article:|
Jacob O, Kosala M. Autologous chin graft for implant site augmentation revisited. J Int Clin Dent Res Organ 2021;13:68-72
| Introduction|| |
The placement of endosseous implants in the maxillary anterior postextraction of teeth has always been challenged by the advanced ridge resorption which reduces the horizontal and vertical dimensions. Inadequate horizontal ridge width has always been a common finding in the maxillary anterior region due to the ridge resorption patterns. Horizontal ridge augmentation is an option prior to placement of implants to create adequate bone width for the primary stability of implants. Several procedures are available to augment the ridge resorbed prior to placement of implants. These techniques include autologous bone grafts including onlay grafts, interpositional bone grafts, bone regeneration (GBR), and combination of these techniques.
Autogenous bone grafts are considered “Gold Standard” due to their inherent osteogenic, osteoinductive, and osteoconductive properties. A variety of donor sites such as ilium, calvaria, tibia, maxilla, and mandible are available for the surgeon for correction of osseous defects. However, a local donor site provides for a convenient surgical site and accessibility. Local donor sites also help to reduce the operative time and anesthesia, thus allowing the procedure to be performed by a single team and on an outpatient basis. Decreased morbidity of the local site along and use of local anesthesia instead of general anesthesia increases the cost–benefit ratio for this technique.
A variety of local donor sites have been used for the management of local alveolar ridge defects and augmentation of bone for implant placement. Bone harvested from maxillary tuberosity and bony exostoses is commonly used for periodontal and alveolar bone defects and for augmentation of ridge prior to endosseous implant placement. Misch had described a technique using mandibular ramus block graft to augment alveolar process prior to placement of implants. However, due to the potential to damage the inferior alveolar neurovascular bundle and compromised surgical accessibility to the donor site, the utilization of this site for a good corticocancellous bone graft is less feasible.
Mandibular symphysial graft has been successfully used for reconstruction in the maxillofacial region including secondary alveolar clefts osteoplasty, reconstruction of orbital floor, interpositional grafts for management of malunion and reunion of maxillary and mandibular fractures, maxillary sinus grafting, and in acquired alveolar defects prior to placement of endosseous implants. This versatility of mandibular block graft has made it an ideal contender for horizontal ridge augmentation prior to endosseous implant placement using autologous bone grafts.
| Case Report|| |
A 28-year-old female patient reported to the outpatient department with chief complaints of missing upper anterior teeth, extracted about 10 years back due to extensive caries. The patient had not replaced the missing teeth until now owing to academic reasons. The patient wished to rehabilitate the tooth with a fixed prosthesis. The patient's medical and dental history was elicited, which revealed no other systemic comorbidities. Extraoral and intraoral examinations were carried out and all maxillofacial and oral structures appeared normal. On examining the edentulous area of the upper right lateral incisor, a reduced horizontal ridge width of 3 mm with adequate ridge height and keratinized tissue was found [Figure 1]. The patient was advised cone-beam computerized tomography for radiological evaluation and blood investigations. The laboratory investigations were within normal limits. The radiological evaluation revealed 3.2 mm of residual bone width [Figure 2]. The patient was given options of tooth-supported or implant-supported fixed prosthesis. The patient opted for implant-supported fixed prosthesis. The procedure of horizontal ridge augmentation using mandibular symphyseal graft was discussed and patient consent was obtaoned prior to performing the procedure.
|Figure 2: axial view of the residual alveolar ridge using cone-beam computerized tomography|
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Post phase I therapy which included scaling, phase II surgery to augment the residual ridge with autologous onlay graft was performed under local anesthesia using lignocaine 2% with 1:80000 adrenaline. A full-thickness flap was raised in the edentulous area of tooth #12 [Figure 3]. Decortication was performed on the buccal cortical plate using a piezoelectric surgical unit to expose the medullary spaces [Figure 4]. The donor site was exposed with a full-thickness flap using a trapezoidal incision apical to the attached gingiva [Figure 5]. Using a piezoelectric surgical unit, a rectangular block graft was harvested measuring 13 mm × 7 mm [Figure 6] and [Figure 7]. The harvested graft was placed in saline to maintain the viability of the graft. The donor site was covered using a composite graft consisting of β-tricalcium phosphate and hydroxyapatite was placed and biocollagen membrane (resorbable collagen membrane) was used for GBR [Figure 8]. The graft was trimmed using osteotomes and fixed onto the residual alveolar ridge as an onlay using 9 mm titanium screws. The dead spaces around the graft postadaptation were covered using composite graft and biocollagen membrane [Figure 9]. The recipient site flap was then closed using 3-0 silk sutures, while the mucoperiosteal flap of the donor was covered using layered suturing technique with 4-0 Vicryl sutures [Figure 10]. Postoperative instructions were given and the patient was prescribed antibiotics and chlorhexidine mouth was (0.2%) for 14 days. The patient was kept on regular review for a duration of 6 months during which the increase in horizontal ridge dimension was evident [Figure 11].
|Figure 5: incision and full-thickness flap raised in the mandibular symphyseal region|
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|Figure 8: guided bone regeneration using composite graft and biocollagen membrane in the donor site|
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|Figure 9: rigid fixation of the harvested block graft with titanium screw and guided bone regeneration|
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Seven months post the first surgical phase for augmentation, the second surgical phase to place endosseous implants was carried out. A full-thickness mucoperiosteal flap was raised and the edentulous ridge was exposed [Figure 12]. An increase in crestal width of 2 mm was appreciated on elevation of a full-thickness flap. The screw used to fix the onlay graft was removed and endosseous implant of dimensions 3.3 mm × 11 mm was placed [Figure 13] and GBR was carried out in the space created by removal of screw using composite graft and biocollagen membrane. Six months metal-ceramic crown was placed to complete the prosthetic rehabilitation [Figure 14]. The patient was given posttherapy instructions on oral hygiene and is currently under regular recall for maintenance and supportive care.
|Figure 14: rehabilitation with PFM crown buccal view and cone-beam computerized tomography assessment|
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| Discussion|| |
There are several reports of bone grafting before or in a combination of implant placement in patients with severe atrophy in the posterior maxillary region. On the contrary, there are very few reports and studies on the utilization of mandibular symphyseal block graft for ridge augmentation in the maxillary anterior region. Mandibular bone grafts provide good-quality corticocancellous autografts with reduced resorption rates compared to extraoral autografts harvested from the tibia, iliac crest, or ribs. Owing to the embryological origin of the mandibular grafts, they possess inherent biological properties of maintaining the architecture, quality, and density of bone. This proves to be of higher biomechanical advantage for placement of functionally loaded implants.
Bone harvested from the mandibular symphyseal region is primarily corticocancellous in nature, thus allowing rigid fixation in situ with good primary stability. This rigid fixation reduces the incidence of migration of the graft which is routinely encountered in particulate bone grafts. The other major advantage is these can be carved and placed over the residual ridge to adapt intimately and this provides good alveolar ridge contour.
Another major concern regarding residual ridge augmentation is the resorptive rates of grafts. Autogenous grafts of membranous origin have an inherent advantage of less resorption as compared to endochondral origin autografts or other substitutes. The use of intraoral grafts provides this added advantage to the fact that they can be harvested in the dental office setup under local anesthesia with a reduced cost–benefit ratio. On an average, the predictable increase of 4–5 mm (6 mm average) is appreciated horizontally and 2 mm vertically using mandibular autografts. Chiapasco in 1999 compared the rates of resorption of GBR versus block grafts using symphyseal grafts. In his study, he found a resorption rate of a maximum of 25% in block grafts as compared to 40% in GBR.
Decortication of the recipient site is generally carried out to expose the medullary spaces and establish a good collateral blood supply to maintain the viability of the graft during the healing phase. On an average, 4–6 months of healing is essential prior to placement of dental implants in the augmented site which increases the success and predictability of the implant site.
Some major disadvantages of using mandibular symphyseal autografts are potential paresthesia of mental nerve, infection, damage and tooth vitality of mandibular anterior teeth, and postoperative appearance of the chin. Mandibular symphysis graft is a highly predictable source for intraoral autograft harvesting that can be performed in the dental office setting under local anesthesia with low morbidity. The intraoral approach reduces the incidence of cutaneous scarring, thus making this a highly predictable and reliable donor site for corticocancellous autografts for residual ridge augmentation.
Another technique to augment the residual ridge for implant placement is the ridge split and expansion technique given by Summers in 1994 for thin residual ridges. However, this technique has a minimal residual ridge requirement of 3 mm as proposed by Summers in 1994 owing to the assumption of this being the residual cancellous bone availability. Katranji et al. in 2007 proposed a minimal availability of 4–5 mm with 1.0–2.1 mm of cortical bone and remaining cancellous bone to perform ridge split and expansion for implant placement. Owing to this limitation in our study, autologous block graft technique was used as the residual ridge width was utilized as the minimal available bone was 3.2 mm.
| Conclusion|| |
Keeping in view the increased requirements of the modern-day implant dentistry, management of residual ridge deformities has become a common day to surgical procedure which is routinely encountered in the dental office. Horizontal bone loss post extraction has been one of the many challenges in the placement of a biomechanical and functionally loaded implant-supported prosthesis in modern-day implant dentistry. With the advent of various modalities to augment the residual alveolar ridge defects, a wide array of choices are available for the dentist. However, autologous block grafts still remain the gold standard for augmentation. Mandibular symphyseal block grafts are ideal due to their ease of access and the quality of bone available. A proper surgical procedure utilizing mandibular symphyseal block grafts is ideal for long-term success and predictability of implant site augmentation.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient's parents have given their consent for his images and other clinical information to be reported in the journal. The patient's parents understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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