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 Table of Contents  
CASE REPORT
Year : 2021  |  Volume : 11  |  Issue : 2  |  Page : 132-135

Rehabilitation using semi-precision attachment in fixed partial denture


1 Department of Prosthodontics, AFDC, New Delhi, India
2 Department of Prosthodontics, CMDC, Chhattisgarh, India

Date of Submission10-Sep-2021
Date of Acceptance12-Oct-2021
Date of Web Publication11-Feb-2022

Correspondence Address:
Dr. Ashish Kalra
AFDC, New Delhi
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijohs.ijohs_26_21

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  Abstract 


The desire to balance between functional stability and cosmetic appeal in partial dentures gave rise to the development of precision attachments, since then, precision attachments have always been surrounded by an aura of mystery. A 35-year-old patient reported a chief complaint of missing upper anterior teeth and wants their replacement. Examination revealed the congenitally missing first and second premolars in the maxillary arch bilaterally, and canines were at first premolar place, which were brought there orthodontically. The patient was planned for 5-unit fixed partial denture from lateral incisor to first molar with semi-precision attachment distal to canine bilaterally, and canines were decided to be converted into the first premolar bilaterally. In this case, it was decided to use the semi-precision attachment and it was procured from Sterngold company, USA. Semi-precision attachments are used to reduce the detrimental stresses and excessive torque on pier abutment, thereby maintaining its health. The decision to use precision attachments in partial denture design should be carefully considered. It is alright to consider such sophistication where the facilities for this precise laboratory work and knowledge of using semi-precision attachment are available.

Keywords: Fixed denture, precision, semi-precision attachment


How to cite this article:
Kalra A, Chowdhury S K, Nandi A K. Rehabilitation using semi-precision attachment in fixed partial denture. Int J Oral Health Sci 2021;11:132-5

How to cite this URL:
Kalra A, Chowdhury S K, Nandi A K. Rehabilitation using semi-precision attachment in fixed partial denture. Int J Oral Health Sci [serial online] 2021 [cited 2022 May 24];11:132-5. Available from: https://www.ijohsjournal.org/text.asp?2021/11/2/132/337499




  Introduction Top


Esthetically pleasing and comfortable restorations can be given with ever-increasing knowledge of the oral environment, technological improvements, and good armamentarium materials.[1] Today's practitioners are provided with changing techniques and a better understanding of the oral environment. This makes it all the more important to reconcile what is actually feasible with the patient's own expectations.

The desire to balance between functional stability and cosmetic appeal in partial dentures gave rise to the development of precision attachments, since then, precision attachments have always been surrounded by an aura of mystery.[2] The use of precision attachments for partial denture retention is a practice builder for the better class of dentistry and helps to elevate the general standard of partial denture prosthetics.[3] The precision attachment is sometimes said to be a connecting link between the fixed and the removable types of partial denture because it incorporates features common to both types of construction.


  Case Report Top


A 35-year-old patient reported a chief complaint of missing upper anterior teeth and wants their replacement. History revealed that he had missing teeth since beginning and got the orthodontic treatment done for proclination of upper anterior teeth 5 years back. Examination revealed the congenitally missing first and second premolars in the maxillary arch bilaterally, and canines were at first premolar place, which were brought there orthodontically [Figure 1]. The patient was planned for 5-unit fixed partial denture (FPD) from lateral incisor to first molar with semi-precision attachment distal to canine bilaterally, and canines were decided to be converted into the first premolar bilaterally. Tooth preparation was done and final impression was made using putty and light body using two-stage double-mix putty-wash impression [Figure 2]. Cast was fabricated and die cutting was done. Wax-up was done for 3-unit FPD from lateral incisor to canine replacing canine and converting existing canine as first premolars bilaterally. Key-keyway type of semi-precision attachment was used (Sterngold, USA) [Figure 3]. The keyway of semi-precision attachment was attached distal to distal abutment, i.e., canine [Figure 4] with the help of a surveyor to keep it parallel to long axis of tooth, and casting was done. Care should be taken that the lower surface of attachment should be 0.5–1 mm away from the soft tissue to prevent soft-tissue irritation and ease of cleaning. Casting was finished and placed onto the cast back. Now, wax-up for 2-unit FPD from second premolar to first molar was done with key of semi-precision attachment attached to mesial side of second premolar pontic. Casting was done and the prosthesis was finished [Figure 5]. Metal try was taken in the patient's mouth to confirm that the accurate fit of the prosthesis and key and keyway of semi-precision attachment are seating properly [Figure 6]. After try-in, ceramic application was done. Five-unit FPD consisting of 3-unit FPD from lateral incisor to first premolar and 2-unit FPD from second premolar to first molar was cemented in the patient's mouth [Figure 7]. Group function occlusion was given on both sides, which was verified, and the patient was recalled after 1 month. After 1 year also, the patient is comfortable and is still under follow-up.
Figure 1: Showing the missing teeth

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Figure 2: Putty light body impression

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Figure 3: Semi precision attachment

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Figure 4: Wax up

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Figure 5: Metal frame work

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Figure 6: Metal try in

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Figure 7: Prosthesis in Situ

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  Discussion Top


Semi-precision attachment is an attachment that is fabricated by the direct casting of plastic, wax, metal, or refractory patterns. The semi-precision type of retainer has an advantage over the manufactured type in the fact that it is somewhat simpler to construct and hence is less time consuming and, as a consequence, not as costly.[2] A disadvantage is that the parts do not fit together with the same degree of machined precision.[3],[4] Semi-precision partial dentures are retained in the mouth by means of mechanical interlocking components. A specially shaped extension of the partial denture fits into or onto a complementary receiving area or projection of a natural tooth that has been crowned. The components fit snugly and consist of a semi-rigid metal to other surface interfaces, which may also be metal or some other resilient materials such as nylon.[5]

The indications[6] for the use of nonrigid connector in fixed prosthodontics are as follows:

  • Pier abutment: It promotes a fulcrum-like situation that can cause the weakest of the terminal abutments to fail and may cause the intrusion of the pier abutment.
  • Malaligned abutment: Where parallel preparation might result in devitalization. Such situation can be solved by the use of intracoronal attachments as connectors
  • Mobile teeth: Which need to be splinted together with fixed prosthesis
  • Long-span FPDs: Which can distort due to shrinkage and pull of porcelain on thin sections of framework and thus affect the fitting of the prosthesis on the teeth.


The four types of nonrigid connectors are as follows:

  • Dovetail (key-keyway) or tenon-mortise-type connectors
  • Cross-pin and wing-type connector
  • Split-type connector
  • Loop-type connector.


In this case, it was decided to use the key-keyway type of semi-precision attachment and it was procured from Sterngold company, USA. This case report involves the application of key-keyway type of semi-precision attachment, which is known to reduce detrimental stresses and excessive torque on the pier abutment, thereby maintaining the periodontal health of the remaining teeth.

There is a conflict in opinion on placement site of nonrigid connector. Markley suggested placement on one of the terminal abutments and not at the pier abutment. Adams suggested placing the connector at the distal side of the pier, and if desired, adding one more at the distal side of the anterior retainer, while Gill suggested placing it at one side or both sides of the pier.[7] Carl E Misch[8] recommended that in conventional fixed prostheses, the “male” portion of a nonrigid attachment usually is located on the mesial aspect of the posterior pontic; whereas, the “female” portion is in the distal aspect of the natural pier abutment tooth. This prevents mesial drift from unseating the attachment. However, an implant does not undergo mesial drifting, and the nonrigid connector location is more flexible. For a natural pier abutment between two implants, a stress breaker is not indicated.

Shillingburg et al.[9] suggested placing the connector at the distal aspect of the pier abutment. Since the long axis of the posterior teeth usually leans slightly in a mesial direction, vertically applied occlusal forces produce further movement in this direction. This would nullify the fulcrum effect and the patrix/male of the attachment would be seated firmly in place when pressure is applied distally to the pier. This position has been supported by finite element analysis study done by Oruc et al.[10] In this case, we have placed it on the distal aspect of the pier.

In this case, group function occlusion was given on both sides as canine-guided occlusion should not be given if canine is periodontally weak, canine is missing, or canine is replaced with implant.


  Conclusion Top


The decision to use precision attachments in partial denture design should be carefully considered. Conventional-type FPDs should be used whenever practical because of their lower cost, ease of fabrication, and maintenance and the predictability of results. However, if precision attachment FPD is the treatment of choice because of esthetics, abutment alignment, or the need for greater cross-arch bracing, it must be used with a thorough knowledge and understanding of prosthodontic principles. Intricacies and special problems associated with the precision attachments should also be considered.

It is alright to consider such sophistication where the facilities for this precise laboratory work and knowledge of using semi-precision attachment are available.

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 Top

1.
Caldarone CV. Attachments for partial denture without clasps. J Prosthet Dent 1957;7:206-8.  Back to cited text no. 1
    
2.
Council on dental materials and devices. Status report on precision attachments. J Am Dent Assoc 1976;92:602-5.  Back to cited text no. 2
    
3.
Grosser D. The dynamics of internal precision attachments. J Prosthet Dent 1953;3:393-401.  Back to cited text no. 3
    
4.
Lorencki SF. Planning precision attachment restorations. J Prosthet Dent 1969;21:506-8.  Back to cited text no. 4
    
5.
Preiskel HW. Precision attachments: Uses and abuses. J Prosthet Dent 1973;30:491-2.  Back to cited text no. 5
    
6.
Yaqoob A, Rasheed N, Ashraf J, Yaqub G. Nonrigid semi-precision connectors for FPD. Dent Med Res 2014;2:17-21.  Back to cited text no. 6
  [Full text]  
7.
Banerjee S, Khongshei A, Gupta T, Banerjee A. Non-rigid connector: The wand to allay the stresses on abutment. Contemp Clin Dent 2011;2:351-4.  Back to cited text no. 7
[PUBMED]  [Full text]  
8.
Misch CE. Dental Implant Prosthetics. Mosby; 2005. p. 189-90.  Back to cited text no. 8
    
9.
Shillingburg HT Jr., Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of Fixed Prosthodontics. 3rd ed. Chicago: Quintessence; 1997. p. 85-118.  Back to cited text no. 9
    
10.
Oruc S, Eraslan O, Tukay HA, Atay A. Stress analysis of effects of nonrigid connectors on fixed partial dentures with pier abutments. J Prosthet Dent 2008;99:185-92.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]



 

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