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 Table of Contents  
CASE REPORT
Year : 2016  |  Volume : 2  |  Issue : 1  |  Page : 17-20

A step ahead in post and core technique for patients with limited interarch space


1 Department of Prosthodontics, Faculty of Dental Sciences, SGT University, Gurgaon, India
2 Prosthodontics Private Practioner, New Delhi, India
3 Department of Conservative Dentistry, Faculty of Dental Sciences, SGT University, Gurgaon, India
4 Private Practioner, Dental Consultant, Tooth for Life, Dental Clinic and Implant Centre, Patiala, Punjab, India

Date of Web Publication14-Mar-2017

Correspondence Address:
Reshu Madan
1123, Sector 17B, Iffco Colony, Gurgaon, Haryana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2454-3160.202124

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  Abstract 

The successful treatment of a badly broken down tooth with pulpal disease depends not only on a good endodontic therapy but also on a good prosthodontic reconstruction of the tooth following the root canal treatment. Often, we come across an endodontically treated tooth with little or no clinical crown. In such cases, a postspace is prepared into the canal for the cementation of post and an artificial crown structure called the core is prepared over it to support the fixed partial denture. Post and cores though commonly used now have their own limitations. Failures associated with these systems include the loss of retention of posts and fracture of roots or even root perforations. Moreover, placement of a post in situations with limited interarch space is a challenge for any dentist. The failure rate associated with the conventional techniques would be higher in these conditions. This case report discusses an alternative technique of restoration of a badly broken down endodontically treated tooth with a specially designed post and core attachment to provide the necessary resistance and retention form for the overlying prosthesis in patients with limited interarch space.

Keywords: Cast post, post and core, reduced interarch space


How to cite this article:
Madan R, Phogat S, Bhatia K, Malhotra P, Bhatia G, Singh J. A step ahead in post and core technique for patients with limited interarch space. Saint Int Dent J 2016;2:17-20

How to cite this URL:
Madan R, Phogat S, Bhatia K, Malhotra P, Bhatia G, Singh J. A step ahead in post and core technique for patients with limited interarch space. Saint Int Dent J [serial online] 2016 [cited 2019 May 23];2:17-20. Available from: http://www.sidj.org/text.asp?2016/2/1/17/202124

Dentistry has grown leaps and bound in the past few decades. Endodontic therapy has provided dentistry with the ability to retain teeth that just a few decades ago would have been extracted without hesitation. However, the restoration of endodontically treated teeth has been the focus of considerable controversy and empiricism. Questions arise as how to restore and protect the tooth structure that remains [1] after endodontic treatment. These teeth have special needs that exceed the requirements of teeth with viable pulps because of the weakening and undermining by caries, fracture, tooth preparation, and restoration.[2] The major changes in these teeth include architectural changes, altered physical characteristics, and altered esthetic characteristics. To overcome these changes when there is a significant loss of tooth structure, a post and core restoration is indicated to support and retain the crown. However, in cases of limited interarch space, the failures associated with the conventional technique are high because of limited height of the abutment and loss of a large amount of tooth structure.[1] A successful treatment modality for limited interarch space cases can be a cast post and core with an attachment system.


  Case Report Top


A 23-year-old female patient presented to the Department of Prosthodontics of SGT Dental College, Gurgaon, with a root canal treated mandibular right first molar, i.e. 46 [Figure 1]. The patient did not report any relevant recent dental or medical history.
Figure 1: Preoperative photograph of the tooth

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On examination

  • A clinical and radiographic examination of endodontically treated tooth revealed the need for post and core assembly
  • The tooth was grossly decayed with the entire buccal wall missing due to caries
  • The length of the clinical crown available for crown preparation was found to be less
  • In occlusion, interarch space was also observed to be reduced [Figure 2].
Figure 2: Limited interarch space

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When insufficient tooth structure exists to prepare a tooth for coronal coverage, the clinician must use a technique that restores lost dentin. Therefore, the patient was advised crown lengthening to expose sounder tooth. Furthermore, extrusion of the tooth by orthodontic treatment was advised to the patient. However, the patient refused both the options. Consequently, it was decided to treat the patient with this alternative technique.

Therefore, “A cast post and core with an attachment” was planned for this patient.[1]

Technique

After the endodontic treatment was completed, the length of the distal canal of the tooth was measured to be 13 mm. Postspace was then prepared in the distal canal by removing 8 mm of Gutta-percha with the help of Peeso reamers leaving 5 mm of apical Gutta-percha intact to maintain the apical seal. Hence, a postspace 1.5–2 mm wide and 8 mm in length was prepared. After this, a temporary restoration with polycarboxylate cement was done so as to prevent the fracture of the remaining tooth structure [Figure 3]. The ferrule was then prepared on the remaining tooth structure [Figure 4]. Once the ferrule preparation was complete an impression of the postspace was made using polyvinyl siloxane impression material, this impression was then poured in die stone [Figure 5]. In the laboratory, a post and core assembly was cast with base metal alloys [Figure 6]. After retrieving the cast post and core, a hole was drilled in the casted core, half round in cross section to provide the antirotational effect [Figure 7]. Crown was then cast with an attachment corresponding to the drilled hole [Figure 8]. The assembly was cemented using GIC (Type I). First, the post and core assembly was cemented [Figure 9] followed by the crown with the attachment to fit into the post and core assembly [Figure 10].
Figure 3: Tooth in occlusion after temporary restoration

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Figure 4: Temporary restoration

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Figure 5: Impression

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Figure 6: Cast post and core

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Figure 7: Hole drilled in the cast post and core assembly

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Figure 8: Cast crown

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Figure 9: Cemented post

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Figure 10: Final restoration cemented

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  Discussion Top


Endodontic access into pulp chamber destroys structural integrity provided by the coronal dentin of the pulpal roof and allows greater flexing of the tooth under function. With reduction of the inner cuspal slopes that unite and support the cusps during function by preventing excessive deformation, greater chances of fracture exist. In case of significantly reduced remaining tooth structure, normal functional forces may cause the tooth to fracture in the area of the smallest circumference, frequently the cement-enamel junction. In addition, if these teeth have extensive restoration or caries, their strength and structural integrity are further compromised.

Moreover, the tooth structure exhibits irreversibly altered physical properties. Calcified tissues of pulpless teeth have 9% less moisture content than in vital teeth. The shear strength and toughness of dentin of root canal treated teeth are significantly lower than that of vital teeth. Changes in collagen crosslinking and dehydration of the dentin result in the brittleness of the ET teeth. The combined loss of structural integrity, loss of moisture, and loss of dentin toughness compromises these teeth and necessitates special care in their restoration.

A darkened endodontically treated tooth is a common clinical phenomenon. Biochemically altered dentin modifies light refraction through the tooth and changes its appearance. Inadequate endodontic cleaning and shaping of the coronal area also contribute to this discoloration by staining the dentin from degradation of pulp tissue left in the pulp horns. Medicaments used in dental treatment and cement of root canal fillings can also affect the appearance of these teeth.

Therefore, endodontic treatment is mostly always followed by prosthodontic reconstruction but in special cases, i.e., in grossly decayed teeth, the tooth has to be first reinforced with a post and core before crowning. When this situation is further complicated with decreased clinical crown and reduced interarch space, conventional post and core restoration would probably not be adequate. The alternative technique described in this article achieves internal reinforcement by cementing the semi-precision attachment into the root canal provides the prosthesis with retention and stability. The half round cross-section of the semi-precision attachment provides the antirotational effect to the restoration and thus increases the longevity of the restoration. This technique derives retention from the internal surfaces of the core besides the external surface. However, failures in this system include the fracture of root or even root perforation.


  Conclusion Top


The technique described above was found to be effective for extensively damaged teeth that lack sufficient tooth structure, particularly when combined with insufficient interarch space for a conventional post and core restoration. When insufficient tooth structure exists to prepare a tooth for coronal coverage, the clinician must use a technique that restores lost dentin. First, lengthening the clinical crown by removing supporting alveolar bone to expose more sound tooth structure may be effective, but typically, it produces other problems such as compromising the supporting bone.[3] Second, extrusion of teeth can also be done;[4],[5] however, the patient refused both the options. In addition, the insufficient interarch space would have limited the amount of forced eruption. As a result, it was decided to treat the patient with this alternative technique. At the 6 months recall visit, the prosthesis did not exhibit any evidence of failure, and the patient was satisfied with its function and esthetics.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Ersu B, Canay S. An alternative post-and-core method for patients with limited interarch space. J Am Dent Assoc 2007;138:1464-7.  Back to cited text no. 1
    
2.
Hsu YB, Nicholls JI, Phillips KM, Libman WJ. Effect of core bonding on fatigue failure of compromised teeth. Int J Prosthodont 2002;15:175-8.  Back to cited text no. 2
    
3.
Assif D, Pilo R, Marshak B. Restoring teeth following crown lengthening procedures. J Prosthet Dent 1991;65:62-4.  Back to cited text no. 3
    
4.
Jorgensen MG, Nowzari H. Aesthetic crown lengthening. Periodontol 2000 2001;27:45-58.  Back to cited text no. 4
    
5.
Paul SJ, Werder P. Clinical success of zirconium oxide posts with resin composite or glass-ceramic cores in endodontically treated teeth: A 4-year retrospective study. Int J Prosthodont 2004;17:524-8.  Back to cited text no. 5
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]



 

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