connectors , the portion of a fixed dental prosthesis that unites the retainer(s ) and 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 . we are more accustomed to the use of rigid connector in clinical practice since its placement requires minimum technical and laboratory expertise . the real problem arises when we encounter 5-unit fixed dental prosthesis ( fdp ) with a pier abutment . because of the curvature of the arch , the faciolingual movement of anterior tooth occurs at a considerable angle to the faciolingual movement of molar tooth . these movements can create stresses on the abutments in long - span prosthesis . a non - rigid connector , a stress breaking mechanical union of retainer and pontic , is usually recommended in such situation.[16 ] a 26 year - old male patient [ figure 1 ] reported to the department of prosthetic dentistry with missing teeth # 14 and # 16 , and he had difficulty in chewing and esthetic problems . on examination it was found that the patient had canine - guided occlusion bilaterally . caries was found in # 24 , which was later extracted and an fdp was fabricated . radiologically and clinically , the abutment teeth were having favourable criteria . after discussing all the treatment options and their pros and cons , it was decided to rehabilitate the case with 5-unit fdp using non - rigid connectors on the distal aspect of pier abutment . a semi - precision attachment named plastic dovetail ( stern gold attachments , attleboro , ma , usa ) [ figure 2 ] was selected in this case . it had frictional retention , plastic pattern male and female , with built in paralleling mandrels . intraoral preoperative view semi - precision attachment  plastic dovetail fixation : male / patrix cast as part of pontic pattern ; female / matrix cast as part of crown pattern . space requirements : height  2 mm , preparation depth  2 mm , width tooth preparations were completed [ figure 3 ] and impression was taken with poly ( vinyl siloxane ) impression material.wax pattern was fabricated and recess for the female was cut accordingly to fit the plastic dovetail on distal aspect of pier abutment.surveying was done to determine the position / parallelism of plastic dovetail [ figure 4].plastic dovetail female was placed within the correct contour of the abutment tooth . male pattern was removed from the female pattern , keeping the inside of female pattern free of wax . any extension of the female pattern above the occlusal of the abutment was left remaining.after investing and casting , excess height of the female was reduced , metal try - in of the part with the matrix / female was done [ figure 5].male / patrix pattern was seated in the casted female . adjacent pontic and abutment were waxed up and the mandrel was cut off from the male [ figure 6 ] . casting of the male pattern was contemplated.now matrix and patrix were assembled together [ figure 7].ceramization was done on # 13 , # 14 and buccal facing was done on # 15 , # 16 , and # 17 . tooth preparations were completed [ figure 3 ] and impression was taken with poly ( vinyl siloxane ) impression material . wax pattern was fabricated and recess for the female was cut accordingly to fit the plastic dovetail on distal aspect of pier abutment . surveying was done to determine the position / parallelism of plastic dovetail [ figure 4 ] . male pattern was removed from the female pattern , keeping the inside of female pattern free of wax . any extension of the female pattern above the occlusal of the abutment was left remaining . after investing and casting , excess height of the female was reduced , metal try - in of the part with the matrix / female was done [ figure 5 ] . adjacent pontic and abutment were waxed up and the mandrel was cut off from the male [ figure 6 ] . ceramization was done on # 13 , # 14 and buccal facing was done on # 15 , # 16 , and # 17 . surveying done to check the parallelism metal try - in of the part with the matrix wax pattern of patrix matrix and patrix assembled together postoperative view in smile postoperative intraoral buccal view postoperative occlusal view tooth preparations were completed [ figure 3 ] and impression was taken with poly ( vinyl siloxane ) impression material.wax pattern was fabricated and recess for the female was cut accordingly to fit the plastic dovetail on distal aspect of pier abutment.surveying was done to determine the position / parallelism of plastic dovetail [ figure 4].plastic dovetail female was placed within the correct contour of the abutment tooth . male pattern was removed from the female pattern , keeping the inside of female pattern free of wax . any extension of the female pattern above the occlusal of the abutment was left remaining.after investing and casting , excess height of the female was reduced , metal try - in of the part with the matrix / female was done [ figure 5].male / patrix pattern was seated in the casted female . adjacent pontic and abutment were waxed up and the mandrel was cut off from the male [ figure 6 ] . casting of the male pattern was contemplated.now matrix and patrix were assembled together [ figure 7].ceramization was done on # 13 , # 14 and buccal facing was done on # 15 , # 16 , and # 17 . tooth preparations were completed [ figure 3 ] and impression was taken with poly ( vinyl siloxane ) impression material . wax pattern was fabricated and recess for the female was cut accordingly to fit the plastic dovetail on distal aspect of pier abutment . surveying was done to determine the position / parallelism of plastic dovetail [ figure 4 ] . male pattern was removed from the female pattern , keeping the inside of female pattern free of wax . any extension of the female pattern above the occlusal of the abutment was left remaining . after investing and casting , excess height of the female was reduced , metal try - in of the part with the matrix / female was done [ figure 5 ] . adjacent pontic and abutment were waxed up and the mandrel was cut off from the male [ figure 6 ] . ceramization was done on # 13 , # 14 and buccal facing was done on # 15 , # 16 , and # 17 . surveying done to check the parallelism metal try - in of the part with the matrix wax pattern of patrix matrix and patrix assembled together postoperative view in smile postoperative intraoral buccal view postoperative occlusal view with rigid connectors , an occlusal load applied on the abutment tooth at one end of an fdp ( mainly the molar retainer ) with a pier abutment , the pier may act as a fulcrum . tensile forces may then be generated between the retainer and abutment at the other end of the restoration ( in the canine retainer ) . anterior or posterior abutments may experience extrusive force and the resultant tensile force at the retainer to abutment interface may lead to potential loss of retention for these restorations , thus resulting in marginal leakage , caries of abutment , and fdp failure.[16 ] . 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 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 . 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 . in this case , we have placed it on distal aspect of the pier . the contraindications of using a non - rigid connector in a posterior 5-unit fpd with a pier are as follows : 
 significant mobility of abutments.if the span between the abutments is longer than one tooth.if the distal retainer and pontic are opposed by a removable partial denture or an edentulous ridge , while the two anterior retainers are opposed by natural dentition , allowing the distal terminal abutment to supraerupt.[46 ] 
  significant mobility of abutments . if the span between the abutments is longer than one tooth . if the distal retainer and pontic are opposed by a removable partial denture or an edentulous ridge , while the two anterior retainers are opposed by natural dentition , allowing the distal terminal abutment to supraerupt.[46 ] the bonhomie of rigid and non - rigid connectors can increase the life span of an abutment in 5-unit fdps as it transfers less stress on the abutments . also , allowing physiologic tooth movement , it eliminates any hindrance as against a fixed restoration with all rigid connectors . the selection of right type of connector is an important step when sorting treatment plan .
the use of rigid connectors in 5-unit fixed dental prosthesis with a pier abutment can result in failure of weaker retainer in the long run as the pier abutment acts as a fulcrum . 
 non - rigid connector placed on the distal aspect of pier seems to reduce potentially excess stress concentration on the pier abutment .