Year : 2007 | Volume
: 25 | Issue : 5 | Page : 20--24
Restoring biological width in crown-root fracture: A periodontal concern
B Nandlal, V Daneswari
Department of Pedodontics and Preventive Dentistry, JSS Dental College and Hospital, SS Nagar, Mysore - 570 015, India
Department of Pedodontics Preventive Dentistry, JSS Dental College and Hospital, SS Nagar, Mysore - 570 015
A 10-year-old male child reported to J.S.S. Dental College and Hospital presenting with a vertical crown-root fracture of maxillary central incisor with a history of fall 10 days back. A new treatment protocol was attempted in contrary to various schools of thoughts of coronal fragment removal wherein fractured fragments were approximated and internally reinforced with latest technologies in adhesive dentistry, the goal was to save the tooth, restore its function and esthetics. This case presents the above mentioned philosophy.
|How to cite this article:|
Nandlal B, Daneswari V. Restoring biological width in crown-root fracture: A periodontal concern.J Indian Soc Pedod Prev Dent 2007;25:20-24
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Nandlal B, Daneswari V. Restoring biological width in crown-root fracture: A periodontal concern. J Indian Soc Pedod Prev Dent [serial online] 2007 [cited 2023 Feb 5 ];25:20-24
Available from: http://www.jisppd.com/text.asp?2007/25/5/20/34742
Crown-root fracture is defined as fracture involving enamel, dentin and root cementum.  Maxillary incisors are the most common teeth involved in dental trauma and, most of the times, the crowns are damaged. According to the system adopted by the World Health Organization in its application of International Classification of Diseases to Dentistry and Stomatology (N.502.54), crown-root fractures have been classified as complicated and uncomplicated. 
Frontal and horizontal impacts can result in fracture line starting at some point on the crown and extend longitudinally with or without involving pulp reaching the mesial or distal subgingival area. 
The common approach to management of such fractures is disarticulation of the coronal fragment.  However, this is time consuming and involves loss of natural tooth structure. Further, loss of an anterior tooth has a substantial effect on the psychology of a child. With the latest advances in the field of esthetic dentistry, there is mounting expectation for the earliest restoration of a confident smile.
Taking into advantage, the properties of dentin bonding agents, a conservative approach for the reattachment of fractured fragment was attempted. Following is a case illustrating the utility of these restorative materials in the preservation of the esthetics, biological width as well as permanent restoration and form of an anterior tooth with crown root fracture.
A 10-year-old boy reported to Department of Pedodontics and Preventive Dentistry, J.S.S. Dental College and Hospital with a ten-day-old history of broken upper front tooth following a fall. Initial examination did not reveal any extra-oral soft tissue injury. Intra-oral examination showed a vertical crown root fracture in relation to maxillary right central incisor with Grade I mobility of intact tooth fragment. Buccally, the fracture line was seen to extend from the incisal edge to the marginal gingiva, with a vertical course below the gingival crevice [Figure 1]. Palatally, coronal fragment was firmly held by intact gingival epithelial attachment and connective tissue with the pulp exposed orally. Surrounding soft tissue was found to be normal.
Patient was subsequently investigated. Intra-oral periapical radiograph of the tooth in complaint exhibited two cleavage lines, one oblique extending 3 mm from the distoincisal point angle on the incisal edge to 2 mm apically from the distal CEJ. The other line was seen from the same point on the incisal edge as the former one and extending vertically across pulp chamber. Root formation was found to be incomplete in Nolla stage 9. The adjacent teeth and supporting structures appeared normal [Figure 2].
Clinical and radiographic examinations were suggestive of a vertical crown-root fracture with irreversible pulpitis classified as Class D, wherein all the enamel-dentin lesions involve a mesial or distal crown angle and the incisal or palatal surface or, root cementum. 
The patient and the mother were informed regarding the various treatment protocols applicable with their respective benefits and drawbacks.
With parental consent, immediate esthetics was achieved by reuniting the fracture fragment taking care not to disturb the palatal attachment. The tooth was isolated, rinsed thoroughly with physiological saline and dried. Internal bevels were made in the fractured fragments, which were coated with dentin bonding agent (Prime and Bond NT, Dentsply) [Figure 3]. Internal strengthening of the tooth buccally and palatally was carried out by placing vertical grooves 1 mm on either side of the cleavage line and saucerization at the interface of the fractured fragment, which was reinforced with flowable resin composite (X-flow, Dentsply) [Figure 4]. The tooth was splinted using rectangular stainless steel wire and light cured resin was applied from right canine to left canine [Figure 5]. Occlusal adjustment was performed. An intra-oral periapical radiograph, taken to confirm the alignment of the approximated tooth fragments, revealed a spur of the fragment projecting away from the root outline subgingivally [Figure 6].
Endodontic intervention was initiated immediately, access cavity was prepared and root canal instrumented. Calcium hydroxide and propylene glycol intra-canal dressing was placed and maintained in the canal for three months [Figure 7]. Patient was instructed on the importance of plaque control using chemical and mechanical methods. Reestablishment of the lost biological space was deemed necessary because of the extension of the fracture. The splint was debonded after 10 days. Periodontal flap was raised, odontoplasty of the tooth spur was performed using tapered bur. Smoothness of the root outline was confirmed both clinically and radiologically [Figure 8] and the soft tissues were sutured.
Patient was recalled three months later and the tooth was assessed clinically for gingival sulcus depth and mobility, radiographically for signs of inflammatory root resorption and alveolar crest integrity, all of which were found to be satisfactory [Figure 9]. The root canal was treated conventionally and sealed with lateral condensation technique [Figure 10]. The tooth was restored with laminate veneer [Figure 11].
Clinical and radiographic follow-up for six-month post-operative period showed no abnormalities.
Patients expect adequate esthetics and the ability to confidently smile immediately after the first appointment. In addition, they require that esthetics be maintained throughout the definitive phase as well. 
Using the remaining tooth, instead of temporary resin crown before performing the permanent fixed prosthesis, provides many advantages with respect to shade, morphology, translucency, physiochemical characteristics, patient acceptance, structurally conservative and financial considerations. 
The treatment options depend on the relationship of the fracture to the alveolar crest, degree of pulpal involvement, amount of eruption, apex formation and esthetic requirements of patient. 
Successful treatment occurs when a case is selected correctly based on clinical and radiographic examinations. Treatment must be carefully planned to avoid any accidents such as root fractures or extensive periodontal ligament damage. 
Following management protocols are recommended for this kind of fracture. 
Removal of coronal fragment, immediate extrusion of the root by surgical or orthodontic procedure.Removal of the coronal fragment supplemented by gingivectomy and osteotomy, subsequent restoration with crown.Removal of the coronal fragment, raising of gingival flap immediate endodontic treatment and fragment bonding.Removal of coronal fragment, disarticulation of the radicular fragment followed by intentional replantation with 180 degrees rotation.Removal of the coronal fragment with subsequent restoration above the gingival level.Extraction when the fracture is in more than one-third of the root.
An approach has been quoted for managing crown-root fractures which involves removal of the coronal fragment, raising of gingival flap, immediate endodontic treatment and fragment bonding.  Our approach was dissimilar in a way that dentin-bonding agents were utilized to eliminate the need for disarticulation of the coronal fragment with subsequent steps as suggested. Since this modality adopts the advantages of adhesive concepts with special emphasis on esthetic, biologic and restorative protocol, reattachment of tooth fragments involving minimal invasion of the biological width can be accomplished with this approach.
Esthetic, biological and restorative problems may occur as a result of fracture extending subgingivally and impinging on the biological width.  Bonding the coronal fragment to the root structure can be permanent treatment in some cases,  as was attempted in the present case. However, our case required further endodontic and periodontal interventions to enhance prognosis.
Controversies exist regarding the timing of endodontic intervention of a recently traumatized tooth.  Our case exhibited a history of trauma more than 24 hours and showed fracture involving pulp, indicating little probability of pulp revascularization. This prompted immediate endodontic treatment using calcium hydroxide. The use of this material has been recommended for controlling factors leading to inflammatory root resorption , and stimulating apexification. 
There should be 2-3 mm of biological width on all teeth to protect the body from progression of infection from the gingival sulcus into periodontium and must be reestablished before esthetic and functional recovery. , Further, presence of intact periodontal ligament on the root surface is an important factor for healing without radicular resorption.  In our case, palatal fragment was found to be clinically attached by the junctional epithelium and the connective tissue, disarticulation of which would have resulted in inadvertent gingival bleeding and compromised biological width. Healing occurs by re-vascularization of ruptured periodontal ligament, ruputured Sharpey's fibers and by formation of new gingival adhesion.  Hence, there is need to preserve the biological width, a dimension which was taken care of in the present case by performing odontoplasty. After clinical and radiographic follow-up, laminate veneering was done to restore the smile line and to compensate for the time-lag for final prosthetic treatment.
Because of large incidence of trauma to dental tissues and their supporting structures, knowledge of the techniques is important. Reattachment of tooth fragments involving minimal invasion of the biological width can be accomplished with the approach presented. This is an attempt of easy execution and allows recovery of biological space assuring adequate bone and gingival levels and the absence of resorption of dental structures by substitution or inflammation. Contemporary resin adhesives that allow strong durable bonds to dentin facilitate this option.
|1||Andreason JO, Andreason FM. Traumatic injuries of teeth. 2 nd ed. Saunders Publications: Munksgaard; 1988|
|2||Fariniuk LF, Ferreira EL, Soresini GC, Cavali AE, Baratto Filho F. Intentional replantation with 180 degrees rotation of a crown-root fracture: A case report. Dent Traumatol 2003;19:321-5|
|3||Spinas E, Atlanta M. A new classification for crown fractures of teeth. J Clin Pediatr Dent 2002;26:225-31|
|4||Villat C, Machtou P, Naulin-Ifi C. Multidisciplinary approach to the immediate esthetic repair and long term treatment of an oblique crown-root fracture. Dent Traumatol 2004;20:56-60|
|5||Trushkowsky RD. Esthetic, biologic and restorative considerations in coronal segment reattachment for a fractured tooth: A clinical report. J Prosthet Dent 1998;79:115-9|
|6||Grossman LL Oliet S, Del Rio CE. Endodontic practice. 11th ed. Lea and Febiger: Philadelphia; 1988|
|7||Deardorf KA, Swartz ML, Newton CW, Brown C Jr. Effect of root canal treatments on dentin permeability. J Endod 1994;20:1-5|
|8||Tsukiboshi M. Treatment planning for traumatized teeth. Quintessence Publishing Co. Ltd: Tokyo; 1998|
|9||Kawai K, Masaka N. Vertical root fracture treated by bonding fragments and rotational replantation. Dent Traumatol 2002;18:42-5|