|Year : 2016 | Volume
| Issue : 1 | Page : 89-92
Different techniques for management of pier abutment: Reports of three cases with review of literature
Puja Hazari, Surabhi Somkuwar, Naveen S Yadav, Sunil Kumar Mishra
Department of Maxillofacial Prosthodontics and Implantology, Peoples Dental Academy, Bhopal, Madhya Pradesh, India
|Date of Web Publication||2-Jun-2016|
Sunil Kumar Mishra
Department of Maxillofacial Prosthodontics and Implantology, Peoples Dental Academy, Bhopal, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
This teaching image highlights the CT abdominal imaging finding of 'crocodile jaw sign' which should raise concern about the presence of an incomplete annular pancreas which causes partial encasement of the duodenum.
Keywords: Nonrigid connector, pier abutment, precision attachment
|How to cite this article:|
Hazari P, Somkuwar S, Yadav NS, Mishra SK. Different techniques for management of pier abutment: Reports of three cases with review of literature. Arch Med Health Sci 2016;4:89-92
|How to cite this URL:|
Hazari P, Somkuwar S, Yadav NS, Mishra SK. Different techniques for management of pier abutment: Reports of three cases with review of literature. Arch Med Health Sci [serial online] 2016 [cited 2019 Jun 25];4:89-92. Available from: http://www.amhsjournal.org/text.asp?2016/4/1/89/183343
| Introduction|| |
The occlusal forces applied to a fixed partial denture (FPD) are transmitted to the supporting structures through the pontic, connectors, and retainers. An FPD with the pontic rigidly fixed to the retainer provides adequate strength and stability to the prosthesis and also minimizes the stresses associated with the restoration. But if an edentulous space occurs on both sides of a tooth, creating a pier abutment then physiologic tooth movement, arch position of the abutment, and a disparity in the retentive capacity of the retainers can make a 5-unit FPD a less than ideal plan of treatment. Pontic are considered as heartthrob of abutments since under occlusal load maximum stresses are concentrated on them. Selection of the right type of connector can make a real difference between success and failure. Researchers had given different opinions about nonrigid connectors which are tabulated in [Table 1].,,,,,,,, The purpose of this article is to summarize various treatment approaches to minimize the effect of forces in long span bridges given in cases of pier abutment. The treatment options in case of pier abutment are implant in edentulous spaces or FPD with nonrigid connectors, using precision and semi-precision attachments.
| Case Reports|| |
Restoration using independent implant-supported restorations
A 55-year-old patient presented with missing maxillary first premolar (14) and first molar (16) on the right side. The second premolar (15) was a pier abutment. After complete radiological and medical examination, two implants supported restorations for each missing tooth were planned. Orthopantomograph was taken, bone mapping was done, and implant sizes were determined. In 16 area and 14 area, the first stage surgery was done and an implant fixture measuring 3.75 mm × 8 mm and 2.8 mm × 10 mm (Adin, Israel), respectively, were placed. A shorter implant was placed in 16 area due to the proximity of the maxillary sinus. A narrower implant was placed in 14 area due to prominent canine fossa and thinner cortical plate in that area [Figure 1]. After a waiting period of 6 months for osseointegration, the second stage surgery was done, and porcelain fused to metal restorations were placed. As the pier abutment, 15 was also endodontically treated, it was also restored with a porcelain fused to metal restoration [Figure 2].
|Figure 1: Intraoral radiograph showing implants placed adjacent to pier abutment|
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Restoration using prefabricated precision attachments
A 52-year-old patient visited the Department of Prosthodontics with a chief complaint of inability to masticate and poor esthetics. Intraoral examination revealed missing first molar (16) and second molar (17) of maxillary right side and missing first premolar (24) and first molar (26) of the maxillary left side with deep bite. After discussing all the treatment options, it was decided to rehabilitate the case with 5-unit FDP using nonrigid connectors on the distal aspect of pier abutment and an FDP using rigid connector on the right side. A precision attachment (Vario Soft 3, Bredent, Germany) was selected for this case. It had frictional retention, plastic pattern male and female, with built in paralleling mandrels. Tooth preparations were done with respect to canine (23), second premolar (25), and second molar (27) on left side and impressions were made. Wax pattern was fabricated with patrix/male as a part of pontic pattern and matrix/female as a part of a crown pattern. Accurate alignment of female part is crucial. This is accomplished with a dental surveyor. After casting, metal try-in of the individual units was done to verify proper seating and then finally restorations were finished [Figure 3]. Mesial 3-unit bridge with keyway was cemented first and then distal 2-unit bridge with key was cemented with glass ionomer cement (GC, Fuji, America) [Figure 4].
|Figure 4: Postcementation occlusal view of 5-unit fixed movable prosthesis|
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Restoration using customized semi-precision attachments
A 30-year-old patient presented with missing mandibular first premolar (44) and first molar (46) on the right side for FPD [Figure 5]. Due to financial factors, patient cannot afford for dental implants and FPD with precision attachment. FPD with a semi-precision attachment was fabricated with a key-keyway or Tenon-Mortise connector. Mortise (female) part prepared within the contours of the wax pattern of the retainer. Casting was done and the first segment was cemented [Figure 6]. For the second portion, a second impression was made. Care was taken to make the impression of the female portion with accuracy. Second casting was done with a tenon (male) portion attached to the pontic. Metal try-in of the second segment was done and proper key-keyway fitting was verified. Ceramic build up was done. The second segment was cemented [Figure 7].
| Discussion|| |
The existence of pier abutment which promotes a fulcrum-like situation that can cause the weakest of the terminal abutments to fail and may cause the intrusion of a pier abutment. There is a need for stress breakers on a pier abutment which is supporting prosthesis on both ends as nonrigid connector so that shear stresses can be transferred to supporting bone rather than concentrating them in connectors. A stress breaker minimizes mesiodistal torquing of abutments and permits them to move independently. The bonhomie of rigid and nonrigid connectors can increase the lifespan of an abutment in 5-unit FDPs as it transfers less stress on the abutments. Furthermore, allowing physiologic tooth movement, it eliminates any hindrance as against a fixed restoration with all rigid connectors. The precision attachment is indicated in cases with compromised periodontal conditions to reduce the stresses on the abutment tooth. It is contraindicated in patients with abnormally high caries rate and where there is inadequate space. The semi-precision attachments were indicated in cases where patient cannot afford costly precision attachments. In this case series, restorations using prefabricated precision attachments (case report 2) and customized semi-precision attachments (case report 3) were used for the patient to overcome the stresses generated in long span bridges in cases of pier abutments. This treatment options are for patient who cannot afford dental implants or patients with poor bone support were implant cannot be placed.
FPDs have been considered the standard of care before the advent of implant therapy. The long-term survival of FPDs has been reported to be 87% at 10 years and 69% at 15 years. Factors that predisposed to failure included nonvital anterior abutments and pier abutments. Hence, in such cases, dental implant can be a better alternative as presented in case report 1 of this article for the patient with good bone support and financially affordable.
| Conclusion|| |
One of the treatment options in case of pier abutment is placing two implants one in each edentulous regions followed by independent crowns. By doing so, we are completely eliminating the load and fulcrum-like situation associated with the pier abutment. However, implants can only be placed after complete medical and radiological evaluation. In cases where implants cannot be placed because of medical or financial conditions nonrigid connectors are advocated. Precision and semi-precision attachments provide room for slight movements which prevents loading of the pier abutment created due to the fulcrum-like situation and increases the lifespan of 5-unit FDP.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]