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 Table of Contents  
CASE REPORT
Year : 2017  |  Volume : 6  |  Issue : 1  |  Page : 44-47

Andrews bridge revisited: A new custom cast ribbed bar and sleeve design fixed removable partial denture


Department of Prosthodontics, Al-Jouf Dental Centre, King Abdul-Aziz Speciality Hospital, Ministry of Health, Jouf, KSA

Date of Web Publication2-May-2017

Correspondence Address:
Arbaz Sajjad
P. O. Box #1978, Sakaka 42421, Al-Jouf
KSA
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jdas.jdas_51_16

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  Abstract 


The loss of teeth invariably is followed by the loss of soft tissue. There is a high incidence (91%) of residual ridge deformity following anterior tooth loss reported in literature; the majority of these are Class III defects that require soft-tissue surgery to augment the ridge defects. Esthetic surgical replacement is difficult and unpredictable, particularly when papilla in the esthetic zone needs to be restored. One choice is a fixed removable prosthesis retained by an Andrews bar and sleeve system. The prosthesis is designed to meet the requirements for esthetics, comfort, phonetics, hygiene, and favorable stress distribution to the abutment and soft tissues. One of the major advantages of an Andrews's bridge over fixed prosthesis is that it can be removed by the patient for improved oral hygiene access. This article describes the procedure for fabricating a new custom cast “ribbed” bar and sleeve design Andrews bridge.

Keywords: Alabama bridge, Andrews bridge, Class III ridge defect, fixed removable partial denture


How to cite this article:
Sajjad A. Andrews bridge revisited: A new custom cast ribbed bar and sleeve design fixed removable partial denture. J Dent Allied Sci 2017;6:44-7

How to cite this URL:
Sajjad A. Andrews bridge revisited: A new custom cast ribbed bar and sleeve design fixed removable partial denture. J Dent Allied Sci [serial online] 2017 [cited 2021 May 7];6:44-7. Available from: https://www.jdas.in/text.asp?2017/6/1/44/205447




  Introduction Top


The art and science prosthodontics involves the replacement and restoration of teeth by artificial substitutes. The primary focus is to restore function, esthetics, and comfort. Fixed prosthodontics, removable prosthodontics, or a combination of both can offer exceptional satisfaction for patient. These prostheses can transform an unhealthy, unattractive dentition with poor function into a comfortable, healthy occlusion capable of years of further service with enhanced esthetics.[1] Having said that it would do good to remember that, the correct choice of treatment for any patient depends on a thorough history and examination and an accurate diagnosis. Decisions concerning the type of the restoration involve many factors - caries, existing restorations, tooth vitality, shape, angulation, oral hygiene, cost, and experience.

The loss of teeth invariably is followed by the loss of soft tissue. Loss of residual ridge contour may lead to unaesthetic open gingival embrasures, food impaction, and percolation of saliva during speech.[2] There is a high incidence (91%) of residual ridge deformity following anterior tooth loss;[3] the majority of these are Class III defects. Because patients with Class II and III defects are often dissatisfied with the esthetics of their fixed partial dentures (FPDs), preprosthetic surgery to augment the residual ridge must be carefully considered.[4] Esthetic surgical replacement is difficult and unpredictable, particularly when papilla in the esthetic zone needs to be restored. One choice is a fixed removable prosthesis retained by an Andrews bar and sleeve system. The prosthesis is designed to meet the requirements for esthetics, comfort, phonetics, hygiene, and favorable stress distribution to the abutment and soft tissues.[5] The Andrews bar joins and splints single or multiple abutment teeth on either side of the edentulous area. A precision fit metal sleeve inserts retentively on the bar. The narrow width and great strength allow for restoration of all natural contours without creating unnatural bulk.[6] It is very strong, corrosion resistant and has a molecular stickiness between metal plated surfaces.[7]


  Case Report Top


A 37-year-old male patient of Arabic origin reported to the fixed prosthetic clinic with the chief complaint of poor appearance owing to the loss of mandibular anterior teeth. On clinical examination, teeth #31, 32, and 41 were missing with mild drifting and rotation of adjacent teeth #42 [Figure 1]. The patient gave a history of extraction of #31, 32, and 41 due to periodontal disease 4 years back. The ridge defect was found to be a severe Seibert's Class III (i.e., deficient in both height and width).[8]
Figure 1: Preoperative view

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A conventional FPD could not be planned as it would result in overtly long slanted pontics in an attempt to contact the deficient ridge underneath with poor facial musculature support, food entrapment, and poor esthetics. An implant-retained FPD was a viable alternative but would require prior osseous and connective tissue grafts entailing protracted treatment time and high cost. A decision was thus made to fabricate a custom cast bar and sleeve design Andrews bridge. The Andrews bridge provides good esthetics, improved phonetics, and facial musculature support through its ridge replacing acrylic removable component. Another advantage of Andrews bridge is that it can be removed by the patient for improved hygiene access to the pontic area.[9]

Procedure

During the first visit, diagnostic irreversible hydrocolloid impressions (Bosworth Supergel ®, Bosworth Company; Skokie, IL: USA) were made, and study casts were obtained. A diagnostic mock-up was performed, and a labial putty index (Express ™, 3M ESPE Dental Products; St. Paul, MN: USA) was fabricated [Figure 2] which would be used as a guide to determine the optimal position of the bar during wax-up later.

  1. At the second visit, teeth #33 and 42 were prepared, and a polyvinyl siloxane (PVS) impression (Express ™, 3M ESPE Dental Products; St. Paul, MN: USA) was made in a stock tray (Jescoform DR 203, Aesculap Inc., Corporate Parkway; Center Valley, PA, USA) and poured with type IV gypsum (Prima-Rock, Whip Mix Corp. Farmington Ave; Louisville: KY, USA)
  2. The bar and coping assembly was waxed (Duo Dip, Yeti Dental Gmbh; Engen: Germany), and the indexed labial putty matrix was used to determine the position and angulation of the bar. The wax pattern was then sprued, invested, and casted using Ni-Cr alloy (Solibond N, Yeti Dental Gmbh; Engen: Germany) following standard manufacturer's recommendations
  3. The casting was divested, cleaned, and finished. Using a 0.3 mm disk (Komet, Brasseler Gmbh and Co; Lemgo: Germany), very shallow horizontal grooves were scored along the length of the bar to create a “ribbed” effect. The mesial surfaces of both the copings were ground flat and parallel to each other to create guide planes for the removable component
  4. Next, the copings for teeth #33 and 42 were fully veneered with feldspathic porcelain (VMK 95 MetallKeramik, Vita Zahnfabrik; Bad Sackingen: Germany) except on the guide plane surface after which the “ribbed” bar was buffed to a high shine [Figure 3]
  5. During the third visit, the bar and crown assembly was cemented in the patients' mouth [Figure 4] using Type I glass ionomer (Ketac ™ Cem Radiopaque, 3M ESPE AG; Seefeld: Germany), and another PVS impression was made and poured with type IV gypsum (Prima-Rock, Whip Mix Corp. Farmington Ave; Louisville: KY, USA)
  6. The working cast was then duplicated with agar gel hydrocolloid (Precigel, Yeti Dental Gmbh; Engen: Germany), and a refractory cast (Wirovest ®/Begosol ®, Bego; Bremen: Germany) was obtained. The sleeve was then waxed over the bar replica portion on the refractory cast using 0.60 mm casting sheet wax (Casting sheet wax, fine, Yeti Dental Gmbh; Engen: Germany), and over it a small piece of wax retention mesh (Retention mesh, Yeti Dental Gmbh; Engen: Germany) was added to aid in the retention of the metal sleeve within the acrylic [Figure 5]
  7. The wax pattern was sprued, invested, and casted using Ni-Cr (Solibond N, Yeti Dental Gmbh; Engen: Germany) alloy following the manufacturer's recommendations. The casted sleeve was then tried in the patient's mouth, and a pick-up impression was made with PVS (Express ™, 3M ESPE Dental Products; St. Paul, MN: USA). The impression was poured with type IV gypsum (Prima-Rock, Whip Mix Corp. Farmington Ave; Louisville: KY, USA) and on this working cast, and the removable denture component was set up using cross-linked acrylic teeth (Vitapan Cuspiform, Vita Zahnfabrik Gmbh; Germany)
  8. The try-in was performed, and when the patient was satisfied with the esthetics, the denture was acrylized using heat cure poly methyl methacrylate (SR Triplex Hot, Ivoclar Vivadent Gmbh; Liechtenstein: Germany), and a long-curing cycle was followed
  9. At the final visit, the fit-in of the removable partial denture component was done and checked for passive fit and satisfactory retention of the cast sleeve over the ribbed bar [Figure 6]. The patient was then trained how to insert and remove the removable pontic component of the Andrews bridge and educated about the oral hygiene maintenance measures. The patient was recalled at intervals of 1 week, 1 month, 3 months, and 6 months for evaluation. The patient was satisfied with the Andrew's bridge and had no difficulty in maintaining the oral hygiene.
Figure 2: Diagnostic wax-up with the labial putty matrix

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Figure 3: Abutment retainers and the cast bar assembly within the natural contours of the missing teeth

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Figure 4: Retainers and the cast bar assembly cemented on the abutment teeth

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Figure 5: Sleeve wax pattern on the refractory cast; finished casting (inset)

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Figure 6: Postoperative view

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  Discussion Top


It has been observed that there is a high incidence (91%) of residual ridge deformity following anterior tooth loss.[3] In these situations, the conventional FPDs should be ruled out because they give rise to many cosmetic, hygienic, and functional disadvantages as compared to the Andrews bridge. There will be dark triangles, potential food trap areas that cannot be flossed and cleaned. The Andrew's bridge, on the other hand, with its acrylic saddle provides improved esthetics, phonetics, eliminates food traps, and can be removed by the patient for hygiene access.[5] Although many authors have advocated soft-tissue surgeries such as interpositional grafts and onlay grafts to regain the lost ridge volume,[8],[10] only a few of these procedures can increase the ridge height with any predictability.[2]

As mentioned before, an implant-retained FPD was a viable alternative but would require prior osseous and connective tissue grafts entailing multiple surgeries, protracted treatment time, and high cost. The new “ribbed bar” and sleeve design described in this article offers certain advantages over conventional bar and clip attachments. It is inexpensive, can be designed to meet specific situation needs easily, and the “ribbed” bar effect offered the advantage of increased contact area and improved the friction fit between the walls of the bar and sleeve providing better retention. Today, the bar and sleeve techniques have evolved to produce whole new class of prosthesis. Twin Andrews bars and a double tract sleeve allow for a tissue-supported, unilateral free-end saddle partial denture.[11]

Recently, spark erosion technology has been introduced in dentistry. It is made of a primary bar casting joining the implants and a removable metal superstructure upon which the replacement teeth are processed. Both the Andrews bar and the spark erosion overdenture share the similarity of having the advantages of the totally implant supported FPD and the implant supported overdenture.[12] However, their use is limited as they require high laboratory precision, are bulky, and tend to wear out.[13]

Andrews components have been marvelously adapted to implant prosthetics such as the Alabama implant restorative system. It overcomes the same ridge loss problems for implant that Andrews bridge do for natural abutments. Tissue support ability of the removable pontic segment allows restoration of long-span edentulous spaces with fewer implants.[14]


  Conclusion Top


The author in this case report has attempted to describe in detail and with clarity the chairside and laboratory procedure involved in the fabrication of a new custom cast “ribbed” bar and sleeve design Andrews bridge so that others may be encouraged to follow suit. Although not widely used, the Andrews bridge offers a simple, user-friendly, and economic alternative to conventional FPDs and soft-tissue surgical procedures for restoring Class II and Class III pontic ridge defects. Probably, the biggest obstacle to the widespread acceptance of Andrews bridges is the dental fraternity's traditional bias for fixed over removable prosthesis. The success of the Andrews system stems from the fact that it allows the pontic to be entirely ridge borne and only retained and stabilized by the bar.

Acknowledgment

We would like to thank Director, Dental Administration, Al-Jouf for their support.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Rosenstiel SF, Land MF, Fujimoto J. History taking and clinical examination. In: Contemporary Fixed Prosthodontics. 3rd ed. St. Louis: Mosby; 2001. p. 2.  Back to cited text no. 1
    
2.
Rosenstiel SF, Land MF, Fujimoto J. History taking and clinical examination. In: Contemporary Fixed Prosthodontics. 3rd ed. St. Louis: Mosby; 2001. p. 514.  Back to cited text no. 2
    
3.
Abrams H, Kopczyk RA, Kaplan AL. Incidence of anterior ridge deformities in partially edentulous patients. J Prosthet Dent 1987;57:191-4.  Back to cited text no. 3
[PUBMED]    
4.
Hawkins CH, Sterrett JD, Murphy HJ, Thomas JC. Ridge contour related to esthetics and function. J Prosthet Dent 1991;66:165-8.  Back to cited text no. 4
[PUBMED]    
5.
Andrews JA, Biggs WF. The Andrews bar-and-sleeve-retained bridge: A clinical report. Dent Today 1999;18:94-6, 98-9.  Back to cited text no. 5
[PUBMED]    
6.
Andrews JA. The Andrews Bridge: A Clinical Guide. Convington, LA: Institute of Cosmetic Dentistry; 1976. p. 3-7.  Back to cited text no. 6
    
7.
Venugopalan R, Lucas L. Electro Chemical Characteristics of the Alabama Bridge System. Proceedings of the 5th World Biomaterial Congress. Toronto, Canada; 1996.  Back to cited text no. 7
    
8.
Seibert JS. Reconstruction of deformed, partially edentulous ridges, using full thickness onlay grafts. Part I. Technique and wound healing. Compend Contin Educ Dent 1983;4:437-53.  Back to cited text no. 8
    
9.
Sadig WM. Bone anchored Andrew's bar system – A prosthetic alternative. Cairo Dent J 1995;11:11-5.  Back to cited text no. 9
    
10.
McHenry KR, Smutko GE, McMullen JA. Restructuring the topography of the mandibular ridge with gingival autografts. J Am Dent Assoc 1982;104:478-9.  Back to cited text no. 10
    
11.
Andrews J. A unilateral, free-end, Saddle bridge. Dent Today 1998;17:120-1.  Back to cited text no. 11
    
12.
Salinas TJ, Finger IM, Thaler JJ 2nd, Clark RS. Spark erosion implant-supported overdentures: Clinical and laboratory techniques. Implant Dent 1992;1:246-51.  Back to cited text no. 12
    
13.
Kaurani P, Samra RK, Kaurani M, Padiyar N. Prosthodontic rehabilitation of a case with an anterior ridge defect using Andrews bridge. Indian J Dent Sci 2013;5:100-3.  Back to cited text no. 13
    
14.
Mueninghoff LA. The Alabama implant restorative system. S Dent J 1994;6:4-6.  Back to cited text no. 14
    


    Figures

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


This article has been cited by
1 Andrewęs bridge system: A boon for huge ridge defect in esthetic zone
Romesh Soni,Himanshi Yadav,Vikram Kumar
Journal of Oral Biology and Craniofacial Research. 2020;
[Pubmed] | [DOI]



 

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