Journal of Interdisciplinary Dentistry

CASE REPORT
Year
: 2020  |  Volume : 10  |  Issue : 2  |  Page : 87--90

Orthodontic extrusion using a cast post for implant site enhancement


Bhavya Amin, Kennedy Mascarenhas, Meena Aras 
 Department of Prosthodontics, Goa Dental College and Hospital, Panaji, Goa, India

Correspondence Address:
Dr. Bhavya Amin
Lydia Gardens, 1-T-1, ST. Inez, Panaji - 403 001, Goa
India

Abstract

Orthodontic extrusion of a nonrestorable tooth prior to its extraction can help in preserving or remodeling the hard and soft tissues to enable predictable implant placement and a favorable treatment outcome. This case report describes the use of a modified cast post for orthodontic extrusion followed by extraction and immediate implant placement.



How to cite this article:
Amin B, Mascarenhas K, Aras M. Orthodontic extrusion using a cast post for implant site enhancement.J Interdiscip Dentistry 2020;10:87-90


How to cite this URL:
Amin B, Mascarenhas K, Aras M. Orthodontic extrusion using a cast post for implant site enhancement. J Interdiscip Dentistry [serial online] 2020 [cited 2021 Nov 26 ];10:87-90
Available from: https://www.jidonline.com/text.asp?2020/10/2/87/292921


Full Text



 Clinical Relevance to Interdisciplinary Dentistry



This case report involves the disciplines of orthodontics, prosthodontics, and implant dentistryOrthodontic extrusion of a nonrestorable tooth has been carried out in this case prior to extraction and replacement with an implantThe prosthodontic procedure involves the fabrication of a custom cast post shaped in the form of a hook to help orthodontic extrusion as well as fabrication of the final restoration.

 Introduction



An implant-supported restoration is often the preferred choice of treatment for the replacement of a single maxillary anterior tooth. Immediate implant placement is indicated when tooth is deemed unsalvageable due to trauma, endodontic failure, root fracture, internal or external resorption, and extensive caries with the alveolar walls still intact. Achieving an optimal result in the maxillary anterior zone can be a challenging endeavor for the clinician due to high esthetic requirements and sensitive hard- and soft-tissue management.[1] Immediate implants are generally considered only when the hard and soft tissues of the tooth to be extracted are not compromised, but the nature of the alveolar bone found in the anterior maxilla often necessitates the need for augmentative procedures.[2] Although various surgical methods of preservation and augmentation of the peri-implant tissues have been proposed,[2],[3] a favorable and predictable restorative outcome can also be achieved by an alternate nonsurgical method such as orthodontic extrusion.

Orthodontic extrusion of unsalvageable teeth prior to extraction and subsequent implant placement is considered to be an effective nonsurgical method to optimize the hard- and soft-tissue topography of implant recipient sites. Slow extrusion of the tooth using light eruptive forces can stimulate the marginal apposition of the crestal bone and allow the gingival apparatus to migrate with the bone coronally, thereby improving the volume of alveolar bone as well as keratinized gingiva for the implant to be placed.[3],[4],[5]

Depending on the clinical situations encountered, a variety of extrusion methods can be employed. Fixed mechanotherapy involving placement of orthodontic brackets on the involved tooth as well as adjacent teeth and a 0.016″ nickel–titanium wire attached to the brackets is a popular method used. The bracket on the tooth to be extruded is placed more apically compared to the other teeth to effect extrusion. The arch wires can also be modified by incorporating horizontal loops or springs.[2],[4],[5] Other strategies include the cementation of a hooked wire into the root canal of the tooth to be extruded. An elastic connects this wire to another rigid anchor wire inserted into restorations of adjacent anchor teeth. The elastic is changed every 2 weeks.[5] Alternatively, a rectangular stainless steel wire can also be bonded with composite to the anchor teeth and a post with a temporary crown cemented on it can be used as a traction attachment point.[5],[6] Removable retainers with rubber bands, dual-magnet systems attached to an Essig's appliance, and mini implants have also been used.[2],[5]

This case report describes the fabrication of a cast post and core shaped into a hook to serve as a traction attachment point for orthodontic extrusion prior to immediate implant placement.

 Case Report



A 28-year-old male patient reported to the Department of Prosthodontics, Goa Dental College and Hospital, with a fractured left maxillary central incisor. Clinical examination revealed a horizontal cervical fracture of the tooth with minimal tooth structure present above the gingival level with a thin gingival biotype [Figure 1]. Past history indicated that the tooth was endodontically treated. A cone-beam computed tomography (CBCT) scan was advised to enable a detailed three-dimensional evaluation of the fractured incisor and the surrounding bone. The CBCT image showed that the fractured incisor had a short root with a wide obturated canal [Figure 2]. The prognosis of the tooth was considered to be poor due to the lack of adequate tooth structure for supporting a restoration and the short root which precluded any crown lengthening procedures. It was therefore decided to extract the tooth and replace it with an implant. To improve the osseous topography and compensate for crestal bone loss that would occur post implant placement, orthodontic extrusion of the fractured tooth fragment was considered prior to extraction and immediate implant placement. Extrusion of 2 mm was desired keeping in mind the gingival levels of the adjacent teeth and the estimated cervical bone loss that could occur after implant placement.{Figure 1}{Figure 2}

Since the remaining fragment provided an insufficient surface for bonding of a bracket and embedding a wire with a hook into the wide canal supported with composite resin alone could weaken and dislodge it, a cast post was considered to be a better alternative. The cast core was designed to have the shape of a hook to help engage an elastic. The patient was explained the treatment plan as well as duration of the entire procedure and a consent form was obtained from the patient for the same.

The procedure for fabrication of the cast post involved the removal of gutta percha from the root canal, preparation of the post space with Peeso Reamers, and making the post pattern which was then cast. Pattern resin (GC America) was used to make the post pattern with the direct method by first placing a preformed pattern resin post in the lubricated canal and then incrementally building it up with more resin till the desired size and passive fit were obtained. However, the core was modified by shaping it into a hook to serve as a traction attachment point. This pattern was then cast. In addition, to avoid metal display, a layer of opaque ceramic (IPS Classic Opaquer, Ivoclar Vivadent) was applied on the coronal portion [Figure 3] and the post was cemented with self-adhesive resin cement (Rely X U200, 3M ESPE, USA). A 19 gauge stainless steel wire of length equal to the intercanine width was bent to conform to the arch shape. Two perpendicular bends were incorporated into the wire corresponding to the distal edge of the right maxillary central incisor and mesial edge of the left maxillary lateral incisor. This resulted in a small segment of the wire lowered by 5 mm to accommodate the extrusion of the tooth. Placement of the wire was checked to ensure that the direction of force would be along the long axis of the tooth and no tipping forces would be exerted.{Figure 3}

The wire was sandblasted with 50 μ alumina particles followed by the application of an opaque resin (SR Adoro Opaquer, Ivoclar Vivadent) and polymerization in the furnace (Lumamat 100, Ivoclar Vivadent) for 11 min. The wire was then bonded onto the adjacent teeth (three on the right side and two on the left) with composite resin. Traction was provided with the help of an orthodontic elastic engaged into the hook and looped around the wire [Figure 4]. The force exerted by the elastic was measured to be 28 g with a Dontrix gauge. The elastic was changed every 15 days till 2 mm of extrusion was observed over a period of 8 weeks and a stabilization phase of 6 weeks was maintained before implant placement [Figure 5] and [Figure 6]. No supracrestal fiberotomy was performed to enable the attachment apparatus to migrate along with the tooth.{Figure 4}{Figure 5}{Figure 6}

After the retention period, the tooth was carefully extracted using periotomes to minimize bone damage and the implant was placed (3.6 mm × 14 mm, SuperLine, Dentium Co., Seoul, Korea) [Figure 7]. The jumping distance was filled with a xenograft (Bio-Oss®, Geistlich Pharma). Since the final placement torque obtained was 35 Ncm, the implant was loaded immediately by fabricating a provisional restoration on the implant abutment using bis-acryl composite resin material (Protemp 4, 3M ESPE, USA). After a healing period of 6 months, a veneered zirconia ceramic crown was cemented onto the implant abutment [Figure 8] and [Figure 9].{Figure 7}{Figure 8}{Figure 9}

 Discussion



Orthodontic extrusive remodeling, as described by Salama and Salama,[3] is a nonsurgical approach to develop the hard and soft tissues of a recipient implant site by extruding an unsalvageable tooth over 6 weeks and stabilizing it for the same amount of time prior to its extraction and subsequent implant placement. This facilitates predictable implant placement by providing a sufficient amount of peri-implant tissue.[3]

Although the choice of removable or fixed appliances for extrusion is matter of preference, fixed appliances do have the advantage of providing more control over the force and direction. Regardless of the method used, one needs to carry out a thorough clinical and radiographic analysis prior to commencing extrusion. The dentist needs to evaluate the periodontal status of the tooth involved as well as the anchorage teeth, the overjet and overbite, occlusion, interference with tooth movement, and the general condition of the existing dentition.[5]

The technique described in this case report uses a cast post shaped into a traction hook to apply orthodontic forces for tooth extrusion. The cast post was the most feasible option considering the wide obturated canal which would not be suitable to engage a wire as a point of attachment for an elastic. Since the post is cemented into the tooth, fabricating it in the form of a hook enabled forces to be directed along the long axis of the tooth, thereby preventing tipping forces. A 19 gauge stainless steel wire affixed to five adjacent teeth provided anchorage. The perpendicular bends incorporated into the anchorage wire lowered a segment of the wire to accommodate the extrusion of the tooth. The elastic was secured in between two blobs of composite resin to prevent it from drifting along the wire segment and resulting in unwanted forces. Since the applied forces should not exceed 30 g for slow tooth movement,[7],[8] a light, constant extrusive 28 g was applied in this case. This resulted in an extrusion of 1 mm/month. The amount extrusion was calculated to be 2 mm to compensate for the gingival recession post implant placement and place the implant margin in the optimal position. This is of importance in patients with thin gingival biotype prone to recession.[2],[9]

Post extrusion, the patient was kept on a stabilization phase of 6 weeks.[4],[5],[9] The stabilization phase allows for bone remodeling and soft-tissue organization, thereby preventing relapse.[10] Supracrestal fiberotomy was not performed post extrusion since it is shown to negatively affect the soft tissues in cases of implant site development and is considered unpredictable.[2],[5]

 Conclusion



The successful esthetic and functional outcome in implant treatment depends on a good understanding of the hard and soft tissues, proper treatment planning, and implementation of treatment procedures. Considering the inclination toward immediate implant placement in recent years and the need for adjunctive tissue augmentation procedures, orthodontic extrusion presents a viable nonsurgical alternative to enhance implant recipient sites. Although it is time consuming, it can be used to provide a predictable and favorable restorative outcome.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Misch CE. Maxillary anterior single-tooth replacement. In: Misch CE, editor. Dental Implant Prosthetics. St. Louis, MO: Mosby Elsevier; 2005. p. 368-71.
2Alsahhaf A, Att W. Orthodontic extrusion for pre-implant site enhancement: Principles and clinical guidelines. J Prosthodont Res 2016;60:145-55.
3Salama H, Salama M. The role of orthodontic extrusive remodeling in the enhancement of soft and hard tissue profiles prior to implant placement: A systematic approach to the management of extraction site defects. Int J Periodontics Restorative Dent 1993;13:312-33.
4Korayem M, Flores-Mir C, Nassar U, Olfert K. Implant site development by orthodontic extrusion. A systematic review. Angle Orthod 2008;78:752-60.
5Bach N, Baylard JF, Voyer R. Orthodontic extrusion: Periodontal considerations and applications. J Can Dent Assoc 2004;70:775-80.
6Oesterle LJ, Wood LW. Raising the root. A look at orthodontic extrusion. J Am Dent Assoc 1991;122:193-8.
7Minsk L. Orthodontic tooth extrusion as an adjunct to periodontal therapy. Compend Contin Educ Dent 2000;21:768-70, 72, 74 passim.
8Reitan K. Clinical and histological observations on tooth movement during and after orthodontic treatment. Am J Orthod 1967;53:721-45.
9Amato F, Mirabella AD, Macca U, Tarnow DP. Implant site development by orthodontic forced extraction: A preliminary study. Int J Oral Maxillofac Implants 2012;27:411-20.
10Mantzikos T, Shamus I. Forced eruption and implant site development: Soft tissue response. Am J Orthod Dentofacial Orthop 1997;112:596-606.