Annals of Emergency Surgery

Cite this article: Mallick S, Murali PS, Shetty A, Hegde P, Ramesh AS (2017) Accidental Orthodontic Mini-Implant Slippage into the Retromolar Trigone Re-gion: A Case Report. Ann Emerg Surg 2(5): 1025.

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*Corresponding authorSoham Mallick, Department of Orthodontics and Dentofacial Orthopedics, NITTE University, Deralakatte, Manguluru-575017, Karnataka, India, Tel: 91-9167908473; Email:

Submitted: 21 October 2017

Accepted: 13 December 2017

Published: 15 December 2017

Copyright© 2017 Mallick et al.

ISSN: 2573-1017

OPEN ACCESS

Keywords•Miniscrews; Retromolar trigone; CBCT imaging;

Surgical retrieval

Case Report

Accidental Orthodontic Mini-Implant Slippage into the Retromolar Trigone Region: A Case ReportSoham Mallick1*, Murali PS1, Ashutosh Shetty1, Padmaraj Hegde2, and Achalli Sonika Ramesh3

1Department of Orthodontics and Dentofacial Orthopedics, NITTE University, India2Department of Oral and Maxillofacial Surgery, NITTE University, India3Department of Oral Medicine and Radiology, NITTE University, India

Abstract

Miniscrews have proved to be an invaluable addition to an orthodontist’s armamentarium. A proper understanding of implant dimensions, regional anatomy, and proper insertion technique are critical to the success of implant stability, as well as optimal patient safety. This case report deals with the protocol for retrieval of an orthodontic mini-implant which had dislodged into the retromolar trigone region. The implant was accurately located using CBCT imaging software and surgical retrieval was done quickly and efficiently from the retro molar trigone region.

ABBREVIATIONSE-chains: Elastomeric Chains; OPG: Orthopantomograph;

CBCT: Cone Beam Computed Tomography; mm: Millimeter

INTRODUCTIONForeign body ingestion/aspiration episodes are potential

complications in all branches of dentistry. Orthodontic components are usually small and in the moist oral environment, their handling can become cumbersome. Nowadays there is a massive interest generated in the use of orthodontic miniscrews for anchorage preparation. Miniscrews have proved to be an invaluable addition to an orthodontist’s armamentarium [1]. The insertion of miniscrews gives the orthodontist an option of utilizing the concept of “absolute anchorage”.

The complications that can take place during miniscrew placement can be broadly divided into Complications during insertion, Complications under orthodontic loading and Soft Tissue Complications [2]. The complications during insertion include, Trauma to Periodontal ligament or dental root, Miniscrew slippage into the Oropharyngeal region, Nerve Involvement, Subcutaneous Emphysema, Miniscrew bending leading to fracture and torsional stress. Miniscrews can be inserted in one of the following ways, the self-tapping method or the drilling method. Often during insertion, procedural errors may take place and lead to slippage or damage to surrounding vital structures. Prevention is always better than initiating a cumbersome retrieval procedure. This case report deals with the protocol for retrieval of an orthodontic mini-implant which had dislodged into the retro molar trigone region.

CASE PRESENTATION21-year-old female was undergoing fixed orthodontic

treatment at the department of orthodontics, for her Class II Division I Malocclusion with missing lower left first Molar. It was planned to place a mini implant in the retro molar region to upright her mesially tilted lower second molar.

The up righting of mesially lower tipped 2nd molar by attaching 3 bondable buttons on its mesial, buccal and lingual surfaces of the molar respectively (Figure 1). 3 e-chains would be attached from each of these buttons to the implant head. This would help in producing a distalizing, intrusive and up righting movement of the molar. It also avoids undesirable rotation of the molar. This procedure was done in accordance with the case report by Maria Greco et al. [3].

A 10mm length, 0.6mm diameter DentosTM Mini-Implantwas selected for the procedure. While driving the implant onto the ridge in the retromolar region following an incorrect angulation of insertion by the operator, the implant slipped into the lingual pouch area (Disto-lingual to lower right second molar) (Figure 2). Finger manipulation of the area and re-insertion of the implant driver was attempted to retrieve the implant, but the procedure wasn’t successful. At this stage an OPG was taken to localize the implant (Figure 3). The implant was localized distal to the second molar at 12mm from the distal root of the molar. Due to the proximity of the dislodged implant to the oropharyngeal airway and the progressive slipping of the implant deeper into the soft tissues Cone Beam computer tomography [CBCT] imaging was taken. The patient was also instructed to minimize her

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Figure 1 The mesially tilted lower second Molar.

Figure 2 The target area of insertion of the mini-implant. The correct method of drilling the implant would be along the arrow mark distal to the right lower second molar.

Figure 3 The mini-implant was initially localized using an OPG.

Figure 4 The implant was localized in the lingual pouch region close to the oropharyngeal airway. (arrow red color).

Figure 5 Note the proximity of the implant to the oropharyngeal airway.

Figure 6 Position of the implant as shown by the Planmeca ProFaceTM view. Note the proximity of the implant to the lingual nerve.

Figure 7 Retrieved Micro-implant.

swallowing motions and not to have any water or drinks, which may exacerbate the dislodgement.

Location of mini implant

The axial section in CBCT imaging revealed a solitary radiopacity of approximately 10x2mm in size which is at 5mm from the lingual cortical plate of the mandible (Figure 4) and at a distance of 16.8mm from the oropharyngeal space on the right side (Figure 5). Inferior alveolar nerve tracing was done

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to assess the proximity of the radiopaque object (Figure 6) 3D reconstruction showed a solitary radiopacity of size 10x2mm near the angle of the mandible on the right side. It was at a distance of 6.80mm from the inferior alveolar canal and at a distance of 3.77mm from the lower border of the mandible.

Retrieval surgical procedure

The patient was administered Inferior alveolar nerve block, buccal nerve block and lingual nerve block before the surgical retrieval was commenced. An incision was placed over the retromolar trigone region and was extended anteriorly and posteriorly. Reflection was done buccally and lingually and the lingual nerve was visualized. Blunt dissection was carried out towards the lingual side. The implant was detected on extra-oral palpation behind the angle of the mandible and removed using artery forceps. The patient was put on antibiotics and palliative care instructions were given.

DISCUSSION Mini implants are an essential tool for orthodontist as they

help to negate many adverse biomechanical effects in various types of orthodontic tooth movements. In this case report a mini implant was used to upright a mesially tipped right mandibular second molar. During the insertion process, it slipped into the retro molar trigone region.

The dangers of having dislodged foreign bodies in the retro molar trigone region stems from the anatomy of the region. This triangular space is bounded laterally by the inner surface of the mandible, medially by the medial pterygoid muscle, superiorly by the lat eral pterygoid muscle and it com municates with the retromandibular space posteriorly. This triangular space houses the in ferior alveolar and lingual nerves, which enters from the infratemporal fossa. Fraser-Moodie (1958) [4] suggested that the needle fragment must be removed before it approaches the blood vessels and other vital anatomic structures of the head and neck. To avoid infection and oropharyngeal space complications, the surgical retrieval of dislodged foreign bodies in this area is mandatory.

The location of the foreign body in this region is critical for its successful retrieval. The earliest reports by Mark (1984) [5], Bedrock (1999) [6] describe the use of Posterior-Anterior Cephalograms and Lateral cephalograms to visualize the area of needle dislodgement. They retrieved the syringe needles, by giving a vertical incision medial to the anterior border of the ramus of the mandible followed by dissection, avoiding incisions on the lingual aspect of the ascending ramus, so that the inferior alveolar and lingual nerve is not severed. In our case report, Cone Beam Computed Tomography was used for three-dimensional visualization of the area. This helped in determining the exact location of the dislodged implant. Similar case reports were reported by Hassani A et al. [7], also successfully localized a dislodged suture needle in the retromolar region during 3rd molar surgery using this modality. Thus, the use of Cone beam computed tomography imaging modality would give the exact co-ordinates for locating the dislodged body and illustrates the possible directions of migration of the implant during the surgical retrieval procedure.

To prevent accidental dislodgement of mini implants one can use a thicker diameter, longer length and increased taper miniscrew for this region, such as the IMTEC Mini implant system or Spider Screw system. In a case report by Nikhilesh et al. (2017) [8], he suggested a protocol for management of accidentally ingested miniscrews. The author suggested tying floss to the implant head, keeping high speed suction tips, good illumination and gauze packs in the area where the implant is being inserted, as essential keys for preventing accidents. The use of CBCT imaging and Stereolithography accurately reproduces the area of mini implant insertion and is useful to prevent such injuries. Removable acrylic stents or archwires bent denoting the area of implant insertion can help the operator in proper site selection for mini implant placement.

CONCLUSIONThe use of advanced imaging techniques, such as the CBCT

software help to accurately localize the dislodged implant, which minimized the extent of the surgical procedure and saved a lot of time and effort for the operating surgeon. The risks associated with miniscrew placement should be understood by both the clinician and the patient. A proper understanding of implant dimensions, regional anatomy, and proper insertion technique are critical to the success of implant stability, as well as optimal patient safety.

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Figure 8 The area of the surgical retrieval, 5 days after the surgical procedure.

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Mallick S, Murali PS, Shetty A, Hegde P, Ramesh AS (2017) Accidental Orthodontic Mini-Implant Slippage into the Retromolar Trigone Region: A Case Report. Ann Emerg Surg 2(5): 1025.

Cite this article

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