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   Table of Contents    
ORIGINAL ARTICLE
Year : 2017  |  Volume : 21  |  Issue : 3  |  Page : 207-209  

Submandibular fossa augmentation in implant dentistry


1 Oral & Maxillofacial Diseases Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
2 Dental Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran

Date of Submission30-Nov-2016
Date of Acceptance21-Oct-2017
Date of Web Publication16-Jan-2018

Correspondence Address:
Saeedeh Khajehahmadi
Dental Research Center, Mashhad University of Medical Sciences, Vakil Abad Blvd, P.O. Box: 91735-984, Mashhad
Iran
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jisp.jisp_392_16

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   Abstract 

Background: There are two limiting factors for determining the dental implant fixture length in mandibular posterior edentulous region: Inferior dental canal and submandibular fossa. Purpose: Submandibular fossa augmentation is a suggested way to overcome the problem of lingual undercut beneath the mylohyoid ridge in implant dentistry. Materials and Methods: Patients with lingual posterior bony undercut that interferes with the placement of a standard implant with a length of 10 mm were enrolled in this study. Results: This method was used for eight patients in 10 sites. Increased implant length and decreasing the chance of sublingual hematoma due to lingual cortical plate perforation are the results of this study. Conclusions: Submandibular fossa augmentation is a new technique to improve the maneuver of oral surgeons to increase dental implant length in the presence of deep lingual bony undercut.

Keywords: Bone graft, dental implant, submandibular fossa


How to cite this article:
Rahpeyma A, Khajehahmadi S. Submandibular fossa augmentation in implant dentistry. J Indian Soc Periodontol 2017;21:207-9

How to cite this URL:
Rahpeyma A, Khajehahmadi S. Submandibular fossa augmentation in implant dentistry. J Indian Soc Periodontol [serial online] 2017 [cited 2020 Aug 15];21:207-9. Available from: http://www.jisponline.com/text.asp?2017/21/3/207/222494


   Introduction Top


There are two limiting factors for determining the dental implant fixture length in mandibular posterior edentulous region: Inferior dental canal and submandibular fossa.[1]

The problem of insufficient bone between the ridge crest and inferior dental canal is solved by nerve repositioning while there is no recommendation to solve the problem of influential lingual undercut.[2] Short or inclined dental implants to prevent lingual cortical plate perforation, are two suggestions,[3],[4] the former is far from ideal crown/root ratio and the latter is accompanied with compromised occlusion.

Submandibular fossa augmentation that is a form of veneer bone grafting may solve this problem. Hematoma in mouth floor after lingual plate perforation may compromise airway and increase the risk of infection. This risk is more pronounced in second molar site, especially if wide implants have to be inserted and should be parallel with the other implant in this region.[5],[6] The aim of this study is to introduce a practical method for bony augmentation of this undercut and evaluate the results and possible complications.


   Materials and Methods Top


Patients with lingual posterior bony undercut that interferes with placement of a standard implant with a length of 10 mm were enrolled in this study. All procedures were approved by the Institutional Ethics Committee (number 940738) of Mashhad dental school. The patient consent form was obtained.

Crestal incision and buccal/lingual mucoperiosteal flap reflection were done. Detachment of the mylohyoid muscle from inner oblique ridge with the aid of a mediolaterally curved periosteal elevator was encountered. Sharpness of mylohyoid ridge was reduced by round surgical bur and bone graft insertion/fixation beneath the lingual undercut was done [Figure 1]. Cortical vertical part of the graft was equal to the length of the vertical distance between the ridge crest and undercut roof. Horizontal inferior component of the graft was equal to the lingual bony undercut depth. The preferred method for graft immobilization was wire osteosynthesis and reflected mucoperiosteal flaps were sutured back to original position [Figure 2].
Figure 1: Schematic picture: (a) Lingual undercut beneath mylohyoid ridge attachment; (b) Reflection of buccal and lingual full thickness flap; (c) detachment of mylohyoid muscle from mandible and rounding of mylohyoid ridge; (d) graft shaping, adaptation, and wire osteosynthesis for fixation; (e) soft-tissue tensionless closure of incision

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Figure 2: (a) Bony undercut in lingual side of the mandible; (b) submandibular fossa augmentation. The graft is secured to the mandible by wire osteosynthesis; (c) Postoperative graphy; (d) an implant with 12 mm length, Ø 4.3 mm was inserted in the right side. In the left side, a short implant (8 mm) was used previously due to deep submandibular fossa

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Both autogenous or allograft bone can be used. Graft shaping according to the undercut depth was important. Dental implants were inserted after graft consolidation.


   Results Top


This method was used for eight patients in 10 sites. Six cases were unilateral, and two patients had bilateral undercuts interfering with dental implant insertion. The range of available bone for implant insertion before bone grafting was between 7 and 8 mm. After graft consolidation with recipient bed, 12 mm length dental implants were used in all situations. There was no case of hematoma in mouth floor, injury to the lingual nerve, or damage to submandibular salivary gland, subsequent to dental implant insertion. All implants were centralized in the mandibular bone and osseointegrated. All patients were followed up for 6 months after prosthesis fabrication.


   Discussion Top


Lingual cortex perforation during implant placement in posterior mandible irritates tongue.[7] Submandibular space infection and hematoma in mouth floor are two other dangerous complications of this error.[5],[8] Immediate bleeding complications in the posterior mandible is reported rarely, and dental implants causing important bleeding complications were most reported in the mandibular canine region.[9] Lingual aspect of the body of the mandible between the angle and the mental foramen is considered relatively hypovascular, but occasionally anastomosis between submental artery and inferior dental artery happens through unnamed foramina [Figure 3].[10],[11]
Figure 3: Anastomosis between submental artery and inferior alveolar artery through a foramen located in internal aspect of the mandible below mylohyoid ridge (arrow)

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Salivary gland injury subsequent to implant surgery and ranula formation has been reported.[12] Herniation of mylohyoid muscle that is a common finding and predispose sublingual salivary gland at risk of mechanical injury during drilling for implant bed preparation below the internal oblique ridge[Figure 4].[13],[14]
Figure 4: Intraoral view of the right sublingual swelling due to lingual cortical plate perforation and direct injury of sublingual gland

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Lingual concavity is common in posterior mandible, but only small percentages (10%–19%) are influential undercuts and interfere with dental implants.[15],[16] This fact is more important in the second molar region than in the first molar region.[17]

Submandibular fossa augmentation is a practical way to increase the implant length in posterior edentulous mandible when there is bony undercut in lingual side of the mandible. Another indication is when there is need to inferior alveolar nerve repositioning, and the mandibular edentulous ridge is buccal to the maxillary ridge crest. In this special situation, submandibular fossa augmentation has two benefits; avoiding the complications of nerve repositioning and improving final occlusion.

Although submandibular fossa augmentation is a form of medial onlay bone grafting, incidence of graft exposure is low, thanks to appropriate soft tissue thickness. It is expected that this bone graft undergoes small resorption because transferred bone falls in depository field of the basal bone.[18]

An important note in the interpretation of postoperative radiography (periapical or panoramic), taken after dental implant insertion in augmented submandibular fossa is that the dental implant is crossed by inferior dental canal while it is actually lingual to this structure.


   Conclusions Top


Submandibular fossa augmentation is a new technique to improve the maneuver of oral surgeons to increase dental implant length in the presence of deep lingual bony undercut.

Acknowledgement

This study was supported by a grant from the Vice Chancellor of Research of Mashhad University of Medical Sciences.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Yildiz S, Bayar GR, Guvenc I, Kocabiyik N, Cömert A, Yazar F, et al. Tomographic evaluation on bone morphology in posterior mandibular region for safe placement of dental implant. Surg Radiol Anat 2015;37:167-73.  Back to cited text no. 1
    
2.
Khajehahmadi S, Rahpeyma A, Bidar M, Jafarzadeh H. Vitality of intact teeth anterior to the mental foramen after inferior alveolar nerve repositioning: Nerve transpositioning versus nerve lateralization. Int J Oral Maxillofac Surg 2013;42:1073-8.  Back to cited text no. 2
    
3.
Parnia F, Fard EM, Mahboub F, Hafezeqoran A, Gavgani FE. Tomographic volume evaluation of submandibular fossa in patients requiring dental implants. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:e32-6.  Back to cited text no. 3
    
4.
Chan HL, Benavides E, Yeh CY, Fu JH, Rudek IE, Wang HL, et al. Risk assessment of lingual plate perforation in posterior mandibular region: A virtual implant placement study using cone-beam computed tomography. J Periodontol 2011;82:129-35.  Back to cited text no. 4
    
5.
Nickenig HJ, Wichmann M, Eitner S, Zöller JE, Kreppel M. Lingual concavities in the mandible: A morphological study using cross-sectional analysis determined by CBCT. J Craniomaxillofac Surg 2015;43:254-9.  Back to cited text no. 5
    
6.
Quirynen M, Mraiwa N, van Steenberghe D, Jacobs R. Morphology and dimensions of the mandibular jaw bone in the interforaminal region in patients requiring implants in the distal areas. Clin Oral Implants Res 2003;14:280-5.  Back to cited text no. 6
    
7.
Chan HL, Brooks SL, Fu JH, Yeh CY, Rudek I, Wang HL, et al. Cross-sectional analysis of the mandibular lingual concavity using cone beam computed tomography. Clin Oral Implants Res 2011;22:201-6.  Back to cited text no. 7
    
8.
Frei C, Buser D, Dula K. Study on the necessity for cross-section imaging of the posterior mandible for treatment planning of standard cases in implant dentistry. Clin Oral Implants Res 2004;15:490-7.  Back to cited text no. 8
    
9.
Balaguer-Martí JC, Peñarrocha-Oltra D, Balaguer-Martínez J, Peñarrocha-Diago M. Immediate bleeding complications in dental implants: A systematic review. Med Oral Patol Oral Cir Bucal 2015;20:e231-8.  Back to cited text no. 9
    
10.
McGregor AD, MacDonald DG. Vascular basis of lateral osteotomy of the mandible. Head Neck 1994;16:135-42.  Back to cited text no. 10
    
11.
Kawai T, Sato I, Yosue T, Takamori H, Sunohara M. Anastomosis between the inferior alveolar artery branches and submental artery in human mandible. Surg Radiol Anat 2006;28:308-10.  Back to cited text no. 11
    
12.
Nahlieli O, Droma EB, Eliav E, Zaguri A, Shacham R, Bar T, et al. Salivary gland injury subsequent to implant surgery. Int J Oral Maxillofac Implants 2008;23:556-60.  Back to cited text no. 12
    
13.
Mandel L. Plunging ranula following placement of mandibular implants: Case report. J Oral Maxillofac Surg 2008;66:1743-7.  Back to cited text no. 13
    
14.
Loney WW Jr., Termini S, Sisto J. Plunging ranula formation as a complication of dental implant surgery: A case report. J Oral Maxillofac Surg 2006;64:1204-8.  Back to cited text no. 14
    
15.
Braut V, Bornstein MM, Kuchler U, Buser D. Bone dimensions in the posterior mandible: A retrospective radiographic study using cone beam computed tomography. Part 2 – Analysis of edentulous sites. Int J Periodontics Restorative Dent 2014;34:639-47.  Back to cited text no. 15
    
16.
de Souza LA, Souza Picorelli Assis NM, Ribeiro RA, Pires Carvalho AC, Devito KL. Assessment of mandibular posterior regional landmarks using cone-beam computed tomography in dental implant surgery. Ann Anat 2016;205:53-9.  Back to cited text no. 16
    
17.
Yu DC, Friedland BD, Karimbux NY, Guze KA. Supramandibular canal portion superior to the fossa of the submaxillary gland: A tomographic evaluation of the cross-sectional dimension in the molar region. Clin Implant Dent Relat Res 2013;15:750-8.  Back to cited text no. 17
    
18.
Güler AU, Sumer M, Sumer P, Biçer I. The evaluation of vertical heights of maxillary and mandibular bones and the location of anatomic landmarks in panoramic radiographs of edentulous patients for implant dentistry. J Oral Rehabil 2005;32:741-6.  Back to cited text no. 18
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

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