|Year : 2013 | Volume
| Issue : 1 | Page : 72-77
Management of crown root fractures: A novel technique with multidisciplinary approach
Kantheti Sirisha1, Yalavarthy Ravi Shankar2, Naga Sasidhar Yalavarthy3, Koneru Suneetha4
1 Department of Conservative Dentistry and Endodontics, GITAM Dental College and Hospital, Visakhapatnam, India
2 Department of Prosthodontics, GITAM Dental College and Hospital, Visakhapatnam, India
3 Department of Orthodontics, GITAM Dental College and Hospital, Visakhapatnam, India
4 Department of Periodontics, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
|Date of Web Publication||13-Mar-2013|
Plot No.: 23, D. No.: 7-5-148, Ocean View Layout, Pandurangapuram, Visakhapatnam - 530 003, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Crown root fractures with subgingival extent are difficult to manage as the biologic width is difficult to maintain. Various treatment options range from conservative reattachment procedure to radical procedures like extraction. One among them is forced eruption or orthodontic extrusion. A novel technique is reported in the management of fractured anterior tooth using the method of forced eruption. This case report gives an option of multidisciplinary approach that does not compromise the aesthetics even during the treatment.
Keywords: Crown-root fracture, forced eruption, multidisciplinary, orthodontic extrusion
|How to cite this article:|
Sirisha K, Shankar YR, Yalavarthy NS, Suneetha K. Management of crown root fractures: A novel technique with multidisciplinary approach. J NTR Univ Health Sci 2013;2:72-7
|How to cite this URL:|
Sirisha K, Shankar YR, Yalavarthy NS, Suneetha K. Management of crown root fractures: A novel technique with multidisciplinary approach. J NTR Univ Health Sci [serial online] 2013 [cited 2020 Jul 13];2:72-7. Available from: http://www.jdrntruhs.org/text.asp?2013/2/1/72/108524
| Introduction|| |
Main objective of restorative dentistry is to restore tooth form, function, and aesthetics. While achieving this, practitioners often face circumstances where the remaining tooth structure is inadequate for a good definitive restoration. Crown root fracture up to the level of osseous crest is one of those kinds of situation. Main problems associated with subgingival crown root fractures are difficulty in maintaining perfect seal and exposure to coronal leakage.  Treatment options for crown root fractures  are reattachment of the fractured fragment,  surgical crown lengthening, , orthodontic extrusion or forced eruption, , surgical extrusion, , and extraction.
Reattachment of fractured fragment is indicated in situations where the biologic width of 2 mm is maintained.  Indication for surgical crown lengthening in subgingival crown root fractures is to produce a ferrule and to relocate margins of restorations that are impinging on biologic width.  At times, periodontal surgery (crown lengthening) cannot be performed due to compromise on esthetics and osseous support.
Orthodontic extrusion along with the post and core (after endodontic treatment) can be used in such kind of situations. It can be rapid extrusion or slow extrusion. Rapid extrusion is associated with a risk that periodontal ligament will be torn and tooth ankylosis may occur.  It must be followed by an extended retention period to allow remodeling and adaptation of the periodontium with the new tooth position. Intense force can cause root resorption. , Slow extrusion requires forces less than 30 g.  The forces must be adjusted on the basis of the clinically verified speed of extrusion. 
This article presents a case where a badly traumatized tooth is treated endodontically and extruded using novel technique of forced eruption without compromising the esthetics.
| Case Report|| |
A 40-year-old-male patient reported to the dental office with a complaint of mobility in relation to upper front tooth. On examination, fractured right maxillary lateral incisor (#12) which was restored with a metal ceramic crown was noticed. Patient had given a previous history of root canal treatment and placement of a crown for the same and subsequent history of accident which was the cause for the fracture. There was a crown root fracture which was extending up to the alveolar crest on the palatal aspect. Intra-oral periapical radiograph revealed sealed root canal [Figure 1]. Fractured coronal fragment was removed and it was noticed that the fracture was extending palatally till the alveolar crest [Figure 2]. Hence, treatment of forced eruption was planned. [Figure 3] reveals the extent of the fracture radiographically after removal of coronal fragment. Post-space was prepared with anti-rotation notches placed on the proximal aspects [Figure 4] and a custom post and core pattern was prepared using pattern resin. While casting the post, two hooks were fabricated on the core, one on the labial aspect and other on the palatal aspect of the cast core [Figure 5]. The hooks were not in centric contact area and they did not interfere during centric and eccentric movements. The edges of hooks were rounded and the length of each hook was approximately 2 mm, and it did not irritate the tongue and lips. Post was placed in the post-space without cementation for trial [Figure 6] and its extent was evaluated through a radiograph.
|Figure 3: Intra-oral periapical radiograph after removal of coronal fragment|
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This post prepared was the final restoration for the placement of crown over it and care was taken that mesiodistal and buccolingual planes and access of tooth were maintained keeping in mind for future restoration and a pick-up impression was made with alginate [Figure 7]. With the post within the impression, dental stone model was poured with post attached to model or cast, evaluation was made for checking the plane of orientation. Later, the post was coated with metal masking agent and a provisional crown was fabricated using tooth colored heat polymerized acrylic resign in such a way that the hooks were prominent [Figure 8]. The post and core with provisional crown were cemented with Type I Glass ionomer cement Fuji I). A heavy wire called supporting wire (18 Gauge) was contoured from central incisor to canine with loops for retention and was firmly secured by composite resin and it was ensured that the wire did not interfere in any way during protrusive and excursive movements. Distance between hooks and wire was measured [Figure 9] and elastics were attached to hooks on the temporary crown, looping around supporting wire engaging the labial and palatal hooks [Figure 10]. Light force generating elastics were used for the extrusion purpose which generated forces at a range of 1.5-2 Oz. Forces exerted were measured by Dontrix. The patient was instructed to use fresh elastics daily. The patient was instructed to wear the elastics continuously. It was ensured that the forces applied were not more than 30 g.  Periodic evaluation was done every month and the movement was measured [Figure 11]. This process was continued for 6 months. On obtaining desirable extrusion, the supporting wire and composite were removed and circumferential fiberotomy was performed to rearrange the periodontal fibers according to the new position of the tooth.  During a stabilization period of 60 days, no active force was applied. The extruded tooth was bonded (splinted) to adjacent teeth with composite resin (spot welded) to ensure the achieved extruded position of the tooth was maintained. ,
After a maintenance period of 2 months, wire was removed and provisional crown and hooks were trimmed using diamond abrasive burs. Core was polished with ultra-low speed burs and metal polishing disks and pick-up impression was made with polyvinyl siloxane, a ceramic crown was fabricated and cemented [Figure 12] and [Figure 13]. Patient was reviewed periodically for 2 years. There were no signs of post-treatment gingival inflammation and other periodontal changes.
| Discussion|| |
The ultimate goal of any restoration is to maintain an acceptable crown root ratio, maintaining good periodontal health. There is a general agreement that placing restorative margins within/encroaching on the biologic width frequently leads to gingival inflammation, clinical attachment loss, and bone loss, thus the supragingival margin is being classically used. In crown root fractures where the fracture line is extending subgingivally, the biologic width is encroached. The biologic width is commonly stated to be 2.04 mm, which represents the sum of the epithelial and connective tissue measurements. 
Post and core restoration requires a preparation design feature such as ferrule, which increases fracture resistance of endodontically treated tooth.  To place a restorative margin with adequate marginal seal, there is a need of additional 1-2 mm of sound tooth structure making a total requirement of 4 mm necessary.  The effective ferrule length as demonstrated by various authors and personnel ranges from 1.25 to 2.5 mm. The fracture resistance increased when the length of ferrule was 1.5-2.0 mm. 
The biologic or attachment width can be identified for each individual patient by probing under anesthesia to the bone level (referred to as "sounding to bone") and subtracting the sulcus depth from the resulting measurement. This measurement must be performed on teeth with healthy gingival tissues and should be repeated on more than one tooth to ensure an accurate assessment. The information obtained is then used to definitively diagnose biologic width violations, the extent of correction needed, and the parameters for placement of future restorations. 
Procedures for maintaining biologic width are lengthening of clinical crown using techniques like soft tissue re-contouring, soft tissue and bone re-contouring, biometric approach to crown lengthening using proportion and sounding gauges, laser assisted crown lengthening, fixed orthodontic treatment, and surgical template. ,
Forced tooth eruption through orthodontic extrusion is the technique of choice when clinical crown lengthening is necessary for an isolated tooth in the esthetic zone. Surgical crown lengthening procedures like ostectomy can lead to negative architecture. In this case forced eruption provides better results than any other procedure as esthetics is not compromised, provides a provisional guide for the amount of extrusion required, and makes the assessment of oral hygiene and extrusion appreciated by the patient. 
Few contraindications to forced eruption are inadequate crown to root ratio, lack of occlusal clearance for required amount of eruption, and any possible periodontal complications. It can be used only in cases where a minimum of 1:1 crown-root ratio can be achieved after the treatment completion. The force required for anterior tooth forced eruption is 20-50 g. Forces cannot be applied suddenly as that might lead to external root resorption. Supracrestal fiberotomy is performed, so that the crestal bone and the gingival margin are retained at their pre-treatment location and the tooth-gingival interface at adjacent teeth is unaltered. Supracrestal fiberotomy is performed by the use of a scalpel at 7-10 days intervals during the forced eruption to sever the supracrestal connective tissue fibers, thereby preventing the crestal bone from following the root in coronal direction.  Fiberotomy should not be used for teeth associated with angular bone defects, ectopically erupting tooth.
Initially, minimal force application is required followed by progressive increase in application of required forces for extrusion. The amount of forces required for extrusion varies with the configuration and number of roots of the tooth. Various colors of orthodontic elastics with varying lumen diameter that can generate various amounts of forces are available. The force generation by elastic depends on the distance or amount of stretching and period of wearing. It is a fact that more the stretching, more will be the initial forces and as time progresses the decay/dampening of forces occur. It was reported that the force applied reduced by 30% after 2 h of wearing the elastic, and it further reduced in due course of time. 
The advantages of this novel method of extrusion are:
- The post and core with hooks and provisional crown are cemented and after satisfactory extrusion, the provisional crown and the hooks attached to the core are removed using air rotor and diamond burs and post can be left behind. The risks faced during the removal of "J" hook (which is one of the treatment alternatives for extruding a tooth) are need for the use of rotary method to remove the old cement and the hook within the post space. This might widen the post canal space. As the same post and core would be a part of final restoration, risk of over-preparation of the canal does not exist.
- It can be used when there is no adequate amount of tooth structure for cementation of the brackets and also esthetically better acceptable.
- It allows us to assess the orientation and direction of final restoration and helps us to alter it, if needed, by adjusting the position and orientation of wire and composite.
- The amount of eruption achieved can be incisally and cervically measured.
- If further extrusion is required, the incisal edge of the provisional crown can be reduced and the tooth can be extruded further until the required amount of extrusion is achieved.
- It enables the patient to maintain better oral hygiene than a case where conventional brackets are bonded instead of simple wire with composite bonding.
- The oral hygiene of the patient can be assessed during the eruption phase and the prognosis of the final restoration can be determined.
- The provisional crown will function as healing matrix after supracrestal fiberotomy.
| Conclusion|| |
Various treatment options are available for management of a tooth with subgingival crown root fracture. The choice of treatment plan depends upon several factors. This novel technique of multidisciplinary approach is preferred when the area of involvement is esthetically important and limited to single tooth with good periodontal support of adjacent teeth.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13]