Clinical case-stidies: Multi-unit FRC bridge by Dr J Van Rensburg
This is an example of a bridge carried out with the semi-direct technique. Part of the bridge was constructed on a POP model and then finished in the mouth. In this case the occlusal vertical dimension (OVD) was increase by approximately 4 mm.
Patient
Male, 68 years
Case history
The patient had lost his anterior bridge, replacing the UR4, UR3, UR2, UR1, UL1, UL2, and UL3 a year ago. The patient had had the bridge for approximately 20 years but unfortunately some of the retainer teeth had to be removed due to excessive decay. All possible treatment options were discussed with the patient, including replacing the bridge with a new conventional porcelain fused to metal bridge restoration or an implant retained prosthesis to replace the missing teeth. Several non-dental factors complicated the case and after thorough discussion it was decided that a semi-permanent restoration with translucent glass fibre-reinforced composite would be the treatment of choice. This would enable the reconstruction of some function and acceptable aesthetics at an affordable price. The case was further complicated by the loss of posterior support as the patient had lost several teeth over the years. The LL8, LL7, LL6, LL4, LL3, LR5 AND LR8 were missing in the lower jaw and the UR8, UR7, UR6, UR5, UR1, UL1, UL2, UL5 and UL8 were missing in the upper jaw. The UR2, UR3 and LL5 were only root canal treated roots. Due to the posterior collapse the vertical occlusal height ( or occlusal vertical dimention,- OVD) was reduced to such an extent that the patient was suffering chronically from angular challises. No posterior teeth except for the LL5 (root canal treated root) were present in the LL quadrant. A peri-apical radiograph of the LL5 revealed an acceptable but not perfect root canal treatment and caries present in the coronal part of the root. The alone standing UR4 was over erupted due to the loss of the LR5 and no other posterior teeth were present in this quadrant. The periodontal states of the remaining teeth were acceptable but not good. The oral hygiene was acceptable but the patient would need the care of proper oral hygiene treatment in the future. No caries were detected and the patient had a full acrylic temporary crown on the UR3. The soft tissues were found to be in a satisfactory condition despite the loss in posterior occlusion. The patient was wearing a removable acrylic denture (which he detested) and several repairs were necessary due to the close bite directly on the acrylic denture palat of the upper anterior teeth on the denture. Prior to the removable denture the missing teeth were replaced with an acrylic post retained temporary bridge which was also not successful. It was clear according to the history that all possible treatment options within the patient’s financial budget for dentistry were tried and tested without a reasonable long-term result.
Treatment
Three different appointments were scheduled for the completion of the treatment. During the first appointment the vertical occlusal dimension (OVD) was increased by providing a fixed partial denture (FRC bridge) to replace the missing LR5. Two Criss-Cross C&B fibres were bonded from Bu of the LR6 to lingual of the LR4 and the second fibre from lingual of the LR6 to buccal of the LR4. This provided the strong reliable “criss-cross fibre design” on to which the pontic to replace the missing LR5 was built up layer by layer with composite material. The occlusion was adjusted and the OVD was increased by approximately 4 mm. An anatomical fibre post was bonded into the root of the LL5 after all the caries was removed from this root. A composite crown was then constructed layer by layer in the mouth onto the extruding part of the fibre post in the root. The longevity of this restoration could not be guaranteed but this semi-permanent composite restoration had the value of balancing the occlusion on the left side of the dentition. The patient was well informed about the prognosis of this tooth. During the second appointment anatomical fibre posts were bonded into the roots of the UR3and UR2 after all decay was removed. The temporary crown of the UL3 was removed and the tooth was partially restored with composite material on the gingival shoulder that was prepared on the tooth. All edges of this tooth were now visible above the gingival. The fibre frame, consisting of two everStick C&B fibres, a piece of everStick Ortho fibre and everStick Net, was planned and designed. The fitting surfaces of the pontics replacing the UL1, UR1and UR2 were constructed partially with a silicone stint, made in the laboratory, on a POP model. This stint was constructed with a ‘suck-down’ vacuum former. The three partially constructed pontics were reinforced by a u-shaped, everStick ortho fibre followed by placing a piece of everStick fibre net over the composite and ortho fibre. This preformed construction was kept in position by means of the stint and spot-bonded onto the UL3 and the fibre post of the UR2, to secure its position. The first everStick C&B fibre was bonded buccal of the UL4 and buccal of the UL3, all along the previously described partially constructed pontics, buccal of the two anatomical posts (UR3, UR2) and then crossing to the palatal side of the UR5. The second everStick C&B fibre was bonded into the occlusal and mesial aspect of the UL4, palatal of the UL3, all along the previously described partially constructed pontics, palatal of the two anatomical posts (UR3, UR2) and then crossing over the first fibre to the buccal surface of the UR5. The UR5 was completely wrapped in the fibres – all around the clinical crown. The teeth were then built up with composite layer by layer with composite material. The composite was finally shaped and polished to achieve the end result. The patient was requested to schedule the third appointment for the final review and polish of the semi-permanent fixed partial denture.
These models illustrate the pre-operative situation and vertical occlusal dimention very well.
The FRC bridge LR Quadrant to increase the OVD
Increased OVD
Increased OVD with denture in place
End Result
