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 Table of Contents  
DENTAL SCIENCE - CASE REPORT
Year : 2015  |  Volume : 7  |  Issue : 6  |  Page : 740-745  

Prosthetic management of malpositioned implant using custom cast abutment


1 Department of Dentistry, SMS Medical College and Hospital, Jaipur, Rajasthan, India
2 Department of Prosthodontics, Yenepoya Dental College, Mangalore, Karnataka, India
3 Department of Prosthodontics, Yogita Dental College and Hospital, Ratnagiri, Maharashtra, India
4 Department of Periodontics, RUHS College of Dental Sciences, Jaipur, Rajasthan, India
5 Department of Oral Pathology, Yenepoya Dental College, Mangalore, Karnataka, India

Date of Submission28-Apr-2015
Date of Decision28-Apr-2015
Date of Acceptance22-May-2015
Date of Web Publication1-Sep-2015

Correspondence Address:
Aishwarya Chatterjee
Department of Dentistry, SMS Medical College and Hospital, Jaipur, Rajasthan
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0975-7406.163528

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   Abstract 

Two cases are reported with malpositioned implants. Both the implants were placed 6-7 months back. They had osseointegrated well with the surrounding bone. However, they presented severe facial inclination. Case I was restored with custom cast abutment with an auto polymerizing acrylic gingival veneer. Case II was restored with custom cast UCLA type plastic implant abutment. Ceramic was directly fired on the custom cast abutments. The dual treatment strategy resulted in functional and esthetic restorations despite facial malposition of the implants.

Keywords: Custom cast implant abutment, malpositioned implant, UCLA abutment


How to cite this article:
Chatterjee A, Ragher M, Patil S, Chatterjee D, Dandekeri S, Prabhu V. Prosthetic management of malpositioned implant using custom cast abutment. J Pharm Bioall Sci 2015;7, Suppl S2:740-5

How to cite this URL:
Chatterjee A, Ragher M, Patil S, Chatterjee D, Dandekeri S, Prabhu V. Prosthetic management of malpositioned implant using custom cast abutment. J Pharm Bioall Sci [serial online] 2015 [cited 2019 Aug 25];7, Suppl S2:740-5. Available from: http://www.jpbsonline.org/text.asp?2015/7/6/740/163528

With the advent of osseointegrated implants, restorative and prosthetic dentistry has conquered new horizons. The clinical success and outcome of implants are well-documented in the scientific literature. [1],[2],[3],[4],[5] Riding alongside this success story is another picture which is not very pleasant to look at. Complications have arisen which challenge the patient and the restorative dentist as well. [1] All too often these complications are due to poor planning; poor case selection; poor communication between, the patient, surgical and restorative operator, laboratory personnel; faulty operator technique, to name a few. [2] One of the most common and preventable complications is an error in placing the implant in a favorable position facially. [3]

Malpositioned implants often exhibit facial bone dehiscence or fenestration. [4] Several authors have reported multiple techniques for management of misaligned implants. [4],[6],[7] Other than managing the malposed implant, restoration of the surrounding tissue also proves challenging especially if the patient has a high lip line. [8],[9]

Two cases are reported showcasing prosthetic, nonsurgical management of malpositioned implant and one management of soft tissue due to patient's high smile line.


   Case Reports Top


Case report I

A 27-year-old female patient reported to the Department of Prosthodontics, College of Dental Sciences, Davangere, Karnataka, India with a chief complaint of missing teeth. Patient history and clinical examination revealed missing maxillary left lateral incisor whish she had lost due to trauma 1 year back. She had then opted for a fixed dental prosthesis and the option of an endosseous implant was given. The patient had revealed no relevant medical history and results of routine investigations were within normal limits. Following this an endosseous internal hex two stage implant was placed in the edentulous area. After a seven month period of healing second stage surgery was done, the cover screw was retrieved and healing abutment (gingival conformer) was placed. The case was then referred to the Department of Prosthodontics for prosthesis fabrication [Figure 1].
Figure 1: Implant with permucosal extension-note the angulation of the extension

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During treatment planning for restorative options, sub-optimal implant position was observed in three geometric planes-faciopalatal angulation, depth and positioning. In the given situation, following options were presented to the patient:

  • Re-submerging of osseointegrated implant followed by a fixed dental prosthesis, with maxillary left central incisor and canine as abutments
  • Complete surgical removal of malposed implant followed by grafting and a second implant placement at a later date
  • Relocation of the malpositioned implant by segmental osteotomies
  • Prosthodontic management by fabricating customized implant abutment.


The patient did not opt for surgical procedures and consented for prosthodontic management by fabricating customized implant abutment.

A closed tray impression of the implant was made with addition silicone elastomeric impression material (Aquasil; Dentsply). The implant analog was placed in the impression and silicone resin was injected around the analog to mimic gingival tissue. Type III dental stone (Kalstone; Kalabhai) was then poured, and models were made. Materials available for fabrication of the custom abutment were:

  • Inlay casting wax
  • Pattern resin.


Inlay casting wax was chosen for fabrication for relative ease in manipulation and carving properties.

Die lubricant was applied into the internal hex of the implant analog. A drop of inlay was applied into the internal hex compartment, and the abutment screw was slowly screwed into place. This was done a couple of times till enough wax was visible around the abutment screw. Wax was then added to this incrementally so as to obtain a framework similar to the outline of a maxillary left lateral incisor. The abutment screw was carefully removed, and the obtained pattern was inspected for any deficiencies at the internal hex level [Figure 2].
Figure 2: Abutment access as seen from the internal hex aspect

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The wax pattern was immediately invested and cast following standard casting procedures. Fit was checked of the obtained framework in the patient's mouth. Shade was matched, and ceramic build-up was completed directly over the framework. A bisque stage trial of the ceramic crown was done [Figure 3].
Figure 3: Post ceramic firing showing abutment screw and access visible at full smile with marginal gingiva visible

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The crown was glazed and inserted in the patient's mouth. The smile of the patient revealed a high lip line. The abutment screw access was showing at maximum smile as the patient had a gingival show. Hence, it was decided to veneer the abutment screw access with auto polymerizing acrylic resin characterized with pigments [Figure 4].
Figure 4: Gingival veneer on the abutment access characterised to match patient's marginal gingiva

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Intra oral periapical radiograph revealed that the abutment screw had engaged the internal hex threads [Figure 5].
Figure 5: Post attachment Iopa radiograph showing abutment screw engaging the internal hex chamber

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Acrylic resin was used to provide ease of access to the abutment screw access for future procedures. Ceramic pigments were used for characterization of the acrylic veneer. The patient was satisfied with the final outcome [Figure 6].
Figure 6: Post operative view showing smile line and prosthesis with gingival veneer

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Oral hygiene procedures were explained to the patient keeping in mind the abutment gingival tissue interface, a dental floss and an interdental brush were recommended for hygiene around the acrylic veneer.

Case report II

A 25-year-old patient reported to the Department of Prosthodontics, College of Dental Sciences, Davangere, Karnataka, India with chief complaint "my missing tooth has been replaced by implant and now it is ready to receive crown." Patient history, clinical examination, revealed a missing maxillary left central incisor which was lost due to caries during child hood. The patient had opted for endosseous implant, after rejecting removable appliance and a 3 unit Fixed dental prosthesis [FDP] involving maxillary left central incisor and canine. He did not want the adjacent teeth to be prepared for receiving the FDP. The medical history of the patient was normal as were the routine investigations. An endosseous, internal hex root form implant was placed in the edentulous region. After 6 months period of healing surgical re-entry was done cover screw was recovered and healing abutment (gingival conformer) was placed. The case was then referred to the Department of Prosthodontics for prosthesis fabrication. Clinical examination revealed that the implant was malpositioned labially [Figure 7].
Figure 7: Facially inclined implant abutment with ball top impression attachment

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There was no hard or soft tissue defect associated with the implant. Following options were presented to the patient:

  • Re-submerging of osseointegrated implant followed by a fixed dental prosthesis, with maxillary left central incisor and canine as abutments
  • Complete surgical removal of malposed implant followed by grafting and a second implant placement at a later date
  • Relocation of the malpositioned implant by segmental osteotomies
  • Prosthodontic management by combination of customized abutment and hexed UCLA type plastic burn out pattern.


Patient did not opt for a second surgical procedure, and hence a nonsurgical approach was planned. Closed tray impression of the implant was made with addition silicone elastomeric impression material (Aquasil; Dentsply). The implant analog was placed in the impression and type III dental stone (Kalstone; Kalabhai) was then poured, and models were made. A hexed UCLA type plastic burn out pattern sleeve (Biohorizon) was fitted to the implant analog [Figure 8].
Figure 8: UCLA type plastic abutment attached to implant analog in type IV die stone cast

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The angulation of the sleeve was adjusted by trimming and molding. Inlay casting wax was added incrementally to obtain a framework, similar to a central incisor [Figure 9].
Figure 9: Wax pattern fabricated on the trimmed UCLA plastic abutment with provision for abutment screw access

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Necessary carving was done, and it was immediately invested and standard casting procedure was followed.

The obtained casting was tried on the implant in the patient's mouth and checked for fit, angulation, and clearance from adjacent tooth [Figure 10].
Figure 10: Custom cast abutment with the abutment screw in place

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Shade matching was done, and ceramic build-up completed. The abutment screw access was left intact. Trial seating of the crown was done for verification of esthetics, fit and interferences. On confirmation, glazing was done. Postglazing, the abutment screw access was closed with visible light cure (VLC) composite resin. The VLC composite shade was approximated to that of the ceramic crown [Figure 11].
Figure 11: Post ceramic firing with access concealed with VLC composite of same shade as ceramic

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However, the patient did not report for revision of the composite resin for gingival mask. Hence, superior esthetics was not achieved.


   Discussion Top


Implant malposition is an avoidable problem. Proper diagnostic mounting with wax up, use of surgical guide, meticulous planning, good imaging techniques, and a good communication between the operator, restorative doctor, and the laboratory personnel. [1],[2]

Few criteria are to be followed for optimum implant restoration: [2],[3]

  • Ideal hard and soft tissue morphology
  • Adequate interarch space
  • Optimum implant type and position
  • Arch relationship
  • Arch form
  • Existing occlusal relationship
  • Existing occlusion
  • Existing prosthesis
  • Number and position of missing teeth
  • Lip line.


Axially malposed implants are the most common avoidable error. However, when the malposition is mild to moderate, they can be restored adequately with angled or customized implant abutments. Commonly, this is seen in the maxillary anterior edentulous segment. [1],[2],[3],[4] But a compromise in the above-mentioned criteria will result in a compromised restoration and esthetics, especially in the facial gingival contour. [2],[3]

Numerous procedures for restoring a malposed implant prosthetically abound in the literature. [1],[4],[5],[6],[10],[11],[12] Mild to moderately misaligned implants can well be restored with prefabricated angulated abutments, individualized framework, customized abutments and UCLA type abutments. [4],[5],[10],[11],[12] For severe malposition of the implant, surgical procedures have been advocated, ranging from sub apical osteotomy to segmental osteotomy. All these procedures reposition the implant to a more prosthetically restorable position. Removal of implant entails the reconstruction of implant site with block graft, advanced regenerative procedure or submergence of the mal-aligned implant. [6] However, the patient might not want to undergo a second surgical procedure, as was the case in these two cases, plus with added morbidity of the recipient tissue bed, alternative restorative procedures should be explored.

Case I reported with labially placed implant. The implant was restored with a custom cast abutment. Ceramic was directly built up on the abutment and attached to the implant with abutment screw. Case II also reported with a facially placed implant. A UCLA type plastic abutment was used as framework to design a custom abutment. Direct application of ceramic was done on the custom cast abutment and attached to the implant with abutment screw.

Hard tissue in misaligned implant often shows fenestration and dehiscence. [4] Management of soft tissue around malpositioned implants is a challenge to the restorative dentist more so when the patient presents with a high smile line, or with melanin pigmentation in the gingiva. [8],[9],[13] Prosthetically, numerous techniques are reported in the literature for improving soft tissue deficiency. Gingiva colored acrylic resin façade, flexible silicone-based tissue colored material, or removable prosthesis like Andrews Bridge are a few examples of the various techniques attempted. Peri implant tissue correction can also be done, by adding gingiva colored porcelain on the cervical portions of implant supported metal-ceramic restoration. [8],[9],[13]

Case I presented with a high lip line at initial examination. The abutment screw access was visible when the patient smiled. The gingiva of the patient had melanin pigmentation. Auto polymerizing acrylic was tinted with ceramic stains and veneered on the prosthesis. The final outcome was satisfactory to the patient as it camouflaged the access to the surrounding gingiva. Case II did not show such aesthetic deficiency. The abutment screw access was covered with VLC composite resin. A revision of the composite resin was planned at a later dated.

Both the prostheses were fabricated with inlay casting wax. Inlay casting wax possess desirable properties, such as ease of manipulation, predictable coefficient of thermal expansion, absence of residue on burnout. [14] However, if not invested immediately, they lead to distortion as residual stresses are released a long as they are outside the mold. [14],[15],[16] Auto polymerizing acrylic pattern resin and VLC pattern resin provide an alternative to inlay wax in the fabrication of patterns. But proper manipulation technique and immediate investment of the wax pattern tips the balance in favor of inlay casting wax. [17] Inlay wax was used in this study for the fabrication of the wax patterns. It was observed that for both the custom cast abutment the fit was adequate, and the abutment was stable.


   Summary Top


Two case reports are presented, reporting the prosthetic management of malpositioned implant. Custom cast implant abutment was used for case I and a UCLA type plastic abutment was used for case II. Both were fabricated using inlay casting wax. Auto polymerizing acrylic gingival façade was fabricated to mask the abutment screw access visible during the patient's smile in case I. VLC composite resin was used for merging the exposed abutment screw access with the rest of the prosthesis in case II. No characterization was done for the composite resin as it was well above the patient's smile line.

 
   References Top

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Duff RE, Razzoog ME. Management of a partially edentulous patient with malpositioned implants, using all-ceramic abutments and all-ceramic restorations: A clinical report. J Prosthet Dent 2006;96:309-12.  Back to cited text no. 1
    
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Stacchi C, Chen ST, Raghoebar GM, Rosen D, Poggio CE, Ronda M, et al. Malpositioned osseointegrated implants relocated with segmental osteotomies: A retrospective analysis of a multicenter case series with a 1- to 15-year follow-up. Clin Implant Dent Relat Res 2013;15:836-46.  Back to cited text no. 4
    
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Glauser R, Sailer I, Wohlwend A, Studer S, Schibli M, Schärer P. Experimental zirconia abutments for implant-supported single-tooth restorations in esthetically demanding regions: 4-year results of a prospective clinical study. Int J Prosthodont 2004;17:285-90.  Back to cited text no. 13
    
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Rajagopal P, Chitre V, Aras MA. A comparison of the accuracy of patterns processed from an inlay casting wax, an auto-polymerized resin and a light-cured resin pattern material. Indian J Dent Res 2012;23:152-6.  Back to cited text no. 14
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11]



 

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