Functionally Generated Pathway

This presentation describes the functionally generated pathway for fed, rod and single dentures.

1. FUNCTIONALLY GENERATED PATH Dr. Sabnoor Aujla M.D.S III Year MMCDSR, Mullana

2. The functionally generated pathways (FGP) of occlusion refer to the: R egistration of the paths of movement of the occlusal surfaces of the teeth of one dental arch, to the teeth or occlusion rims of the opposing arch, recorded with the help of a plastic medium. DYANAMIC OCCLUSION This indentation/tracing in the lower arch has been made from the functional movement (lateral excursions and protrusive) by the patient.

3. SIMPLE TERMS… Functionally generated path relies on recording in a simple, yet precise manner the pathways traveled by the cusps in the border movements of the mandible. Wax is adapted over the occlusal surface of the prepared tooth. The patient occludes the teeth in the intercuspal position and moves the mandible through all excursions . By this process the tips of the opposing cusps acts a recording styli that carve , in three dimensions in wax, a record of the border movements in all mandibular positions. Stone is brushed and poured into the wax record in the mouth to produce functional core. The stone core is then used in the fabrication of posterior tooth restoration.

4. The distinct advantage of the FGP technique is that, it facilitate to record all dimensions of mandibular border movements at the correct vertical dimension as they are directly influenced by both condylar guidance and anterior guidance. Meyers first described this method in 1933, as a means of obtaining the “Functional Occlusal path” for bridges fabricated by a direct/indirect technique and for dentures.

5. STEPS: REGISTRATION OF FGP RECORD STONE- OCCLUSAL TEMPLATE IS FORMED ARTIFICIAL TEETH ARRANGEMENT IS DONE AGAINST IT (Single Cd) or Wax Up for Group Function and Posterior Disclusion Occlusal Schemes; in regard to the restoration of maxillary posterior teeth (RPD, FPD) The occlusion achieved with the help of this technique is considered to be in great harmony with controlling factors of occlusion namely, the anterior and condylar guidance, occlusal cusps, and the neuromuscular system.

6. USE: a single crown, more complex full mouth reconstructions. It has also been used in developing occlusion for complete and partial dentures and dental implant restorations.

7. PRE-REQUISTIES Presence of an optimal occlusion. Appropriate anterior guidance. Elimination of posterior interferences prior to making the restoration. No missing or broken down opposing teeth. Badly rotated, carious, or poorly restored teeth in the opposing arch will not provide the occlusal pathways needed for shaping the occlusal surface and hence FGP should be avoided in these cases.

8. FUNCTIONALLY GENERATED PATH OCCLUSION IN FPD FUNCTIONALLY GENERATED PATH OCCLUSION IN SINGLE COMPLETE DENTURE FUNCTIONALLY GENERATED PATH OCCLUSION IN REMOVABLE PARTIAL DENTURE

9. OCCLUSAL REDUCTION is done prior to the axial reduction which will afford greater stability to the wax tracing. Piece of wax is cut in a square slightly larger than the occlusal surface of the teeth being restored. Tracing begins by asking the patient to perform functional movements Step 1 : REGISTRATION

10. 11 Step 2 : TO OBTAIN THE FUNCTIONAL CORE • Unneeded portion of the functional index tray is broken off The functional core fabrication is begun by brushing mounting stone on the functional tracing This stone replica of the movement of the cusp tips is called the functional core. It is also referred to as the functional index or counter die.

11. The rest of the tooth preparation is completed and an impression of the quadrant containing the prepared tooth is made using a custom acrylic tray made previo u sl y . 22 It is possible to fabricate a restoration using only the functional core for an opposing model. However it is very helpful to have an anatomic cast against which you can occlude the wax pattern. For this an occlusal registration is made at the intercuspal position using bite registration paste in a bite registration frame.

12. STEP 3: TO ATTACH THE ANATOMIC CAST, FUNCTIONAL CAST AND THE PREAPARED CAST IN THE TWIN STAGE OCCLUDER Sawing of the die is done. Ditching Gingival finish line marked in red pencil The d i e an d th e section s o f th e qu a dran t ca s t reassembled The mounting is ready for wax pattern fabrication.

13. 14 The verticulator is another instrument that is made for use with the functionally generated path technique. It is extremely rigid and provides a precise alignment of cast and functional core. It also utilizes a second upper member (removable not hinged) that can be employed with the anatomic cast. A plane line hinge articulator can also be used for this purpose, but it does not permit the use of an anatomic cast.

14. Axial contours and proximal contacts are checked before preceding to the occlusal surface. 15 The wax added technique is used to form the occlusal morphology. STEP 4 : WAX-UP OF THE PREPARED TOOTH ACCORDING TO FGP

15. Now the occlusal portion of the wax pattern can be completed by waxing against the functional core. 16

16. White liquid shoe polish is painted on the functional core. The articulator is closed so that the functional core is brought in contact with the occlusal surface of the wax pattern. The shoe polish will leave white marks on the occlusal surface of the wax pattern corresponding to the contacts in function. Any areas in white that are not part of the of the desired centric or excursive contact pattern are carved off according to the restoration which would go to mutually protected or group function occlusion. 35

17. restoration should b e in If the mutually p r otec t ed rel at i o n s h i p t h ere should be no contact on the lingual incline of the buccal cusp other than the centric contacts. If on the other hand the restoration to be fabricated in group function, the lingual incline of the buccal cusp should maintain continuous contact with the functional core. In no case should the non working inclines have any contact with the functional core. 36

18. 19

19. Fabrication of fixed partial dentures using functionally generated path technique and double casting Pre treatment appearance. Fabrication of wax pattern with retentive beads for base casting Base casting checked in the mouth. Completed functionally generated path PATTERN RESIN applied on the occlusal surface of the metal coping with retentive beads.

20. Completed double casting . Double casting with functionally generated path cemented Functionally generated path prosthesis in occlusion Once the occlusal morphology was perfected, the MIP contacts were marked using 50-ìm blue articulating papers (Products Dentaires S.A., Vevey, Switzerland) Zinc oxide powder (Dental Products of India, Mumbai, India) was sprinkled and brushed onto the occlusal surface to form a thin, uniform coat, and the patient was instructed to perform the eccentric movements as before. All eccentric contacts became visible with the wiping away of the zinc oxide powder. The wiped out areas were trimmed using an acrylic trimmer to eliminate all eccentric interferences and the FGP patterns were completThe pattern, along with the base casting, was invested and double casted

21. The casting was placed in the oral cavity (before occlusal correction) to check whether it felt comfortable. At the same time the occlusion was checked to identify any high points in the casting. It was observed that there was absolutely no occlusal error identified in the MIP position. Only minimal eccentric interferences were identified and could be eliminated by selective grinding of the casting. The time taken for metal trimming was drastically reduced to 5 min. The patient reported absolute comfort with the prosthesis. The final prosthesis was cemented using glass ionomer cement The present technique has certain advantages over the conventional functional path technique; these are as follows: 1 A cast fixed partial denture with retentive beads was used as a stable base in the present case report. Hence a functional path tray was not required and the problems associated with the tray, including inaccurate seating and distortions, were avoided. 2 To overcome the drawbacks of using inlay wax pattern resin was used ; this has better dimensional stability compared to the waxes. 3 The occlusal morphology was developed and corrected directly in the patient's mouth. The discrepancies which can result due to differences between the teeth in the mouth and that in the master dies could thus be avoided. 4 A functional core used routinely for the conventional FGP technique was not utilized in the present technique. Hence, the discrepancies which may result from the functional core becoming slightly degraded during waxing and metal adjustment were avoided. 5 Further, the use of the opposing functional core to adjust maximum intercuspation and to remove eccentric interferences presupposes that it will be necessary to use the patient's mandibular movements to make final adjustments to the prosthesis. Moreover, eccentric interferences were removed in the patient's mouth directly.

22. Sarfaraz Memon . A Comparative Evaluation of the Effect of Double Casting Technique Using Functionally Generated Path and Conventional Single Casting with Respect to Functional Articulation, Patient Satisfaction and Chair Side Time, in Single Unit Molar Teeth: An In Vivo Study J Indian Prosthodont Soc . 2014 Dec; 14(Suppl 1): 119–125. This study was conducted to evaluate the benefits of the double casting technique with FGP over the conventional casting technique. Ten patients with root canal treated maxillary molar were selected for the fabrication of metal crown. Two techniques, one involving the conventional fabrication and other using functionally generated path with double casting were used to fabricate the prosthesis. A comparison based on various parameters which was done between the two techniques. The change in the height of castings for the double casting group was less compared t o the conventional group and was highly statistically significant ( P  < 0.001). The time taken for occlusal correction was significantly lower in double casting group than the conventional group ( P  < 0.001). The patient satisfaction (before occlusal correction) indicated better satisfaction for double casting group compared to conventional ( P  < 0.01). The functionally generated path with double casting technique resulted in castings which had better dimensional accuracy, less occlusal correction and better patient satisfaction compared to the conventional castings.

23. USES OF F.G.P Preparing the wax pattern directly against the functional model. After making wax pattern against anatomic model, refine the occlusal inclines against functional stone core. After completing the casting against anatomic model, adjust the metal or porcelain occlusal surfaces against the functional model.

24. FGP for RPD

25. Try-in of partial denture framework with inlay wax attached for occlusal registration. (b) Obtaining functionally generated pathway record in eccentric relation RECORDING FGP

26. Functionally generated pathway record seated on master cast. (b) Modeling clay used to block specified areas on the cast Recording the FGP eliminates the need to reproduce mandibular movements on the articulator, and hence the mounting was done on a simple three-point (mean value) articulator. Occluding template with functionally generated pathway record mounted. (b) Occlusal surfaces of teeth modified to fit occluding template

27. Postoperative view with removable partial denture in occlusion Functionally generated path technique utilises the patient's masticatory system to develop occlusion and has the advantages of being simple, accurate, and reliable.

28. FGP for Single Complete Denture

29. Stansbury, in his functional chew-in technique, mounted the maxillary and mandibular casts on an articulator in centric relation at an acceptable vertical dimension. He then adapted a new base plate and fabricated the occlusal rim made of impression compound on the edentulous cast. The compound occlusal rim was at least twice the width of the molar teeth and sufficient in height to receive an impression of the central fosse of the lower teeth. This occlusal rim was then heated and placed in the articulator to record the impression of the fosse of all opposing teeth. STANSBURY TECHNIQUE Stansbury CB. Single denture construction against a non- modified natural dentition. J Prosthet Dent 1951;1:692–9.

30. The occlusal rim was then trimmed bucco-lingually so that only a fin of the compound extending to the central fosse remained and the anterior region was trimmed till the level of indentation of the incisors. Carding wax was then added on the bucco-lingual sides of the occlusal fin. The assembly was then placed in the patient’s mouth and the patient was asked to perform eccentric chewing movements. The opposing teeth cut their path in the soft carding wax and the compound in the central fosse acted as a guide to preserve the cusp height and a stone index was poured in this path. The original mandibular cast was placed on the articulator and maxillary teeth setting was done according to esthetics and centric occlusion. The dentures were processed, remounted, placed opposite the stone index. Interferences were removed in centric relation and eccentric movements to establish bilateral balanced occlusion.

31. FUNCTIONALLY GENERATED PATHWAY IS MADE ON THE UPPER RIM THE FUNCTIONAL REGISTRATION IS POURED TO GET THE POSITIVE REPLICA THE REPLICATED CORE IS PLACED ON THE LOWER MEMBER OF THE ARTICULATOR WHICH CONSISTED THE FGP OF THE LOWER PRESENT TEETH BALANCED TEETH SETTING IS DONE AGAINST THE FGP FOR THE UPPER DENTURE

32. 33 ADVANTAGES: FGPT eliminates the need for adjusting articulator with interocclusal records or a tracing device The excursive movements produced in the mouth are more accurate than those in an articulator. It eliminates the need of face bow transfer. Is simple and can produce precise excellent results.

33. DISADVANTAGES: The occlusion in one of the arches must be complete before functional generated path can be developed. This cannot be effectively utilized for CD opposing RPD. 3. Verification of record in mouth is difficult. 49

34. Classically, the FGP occlusion has been described as “3D static expression of dynamic tooth movement,” since exact occlusal pathways of posterior teeth are captured three-dimensionally in the functional wax

35. REFERANCES Dawson, P. E. Evaluation, Diagnosis, and treatment of Occlusal Problems. Functionally generated path techniques for recording border movements intraorally. C. V. Mosby 1989, 410-433. F. S. Meyer. The generated path technique in reconstruction dentistry. J Prosthet Dent 9; 432-440; 1959

36. Edwin H. Getz. Functional “ Check Bite-Impressions” for fixed prosthodontics. J Prosthet Dent 26; 146-153; 1971 Robert C. King. Stabilizing functional chew in wax records J Prosthet Dent 26; 601-603; 1971 Pankey L. D & Mann A.W. Reconstruction of the upper teeth using a functionally generated path technique. J Prosthet Dent 10; 151-162; 1960