1. Rola Shadid, BDS, MSc, Associate Fellow of AAID
The completely edentulous mandible & maxilla: Treatment plans for fixed restoration
Rola Shadid, BDS, MSc, Associate Fellow of AAID

2. Treatment Options
Carl Misch; Dental implant prosthetics; 2ed; Ch. 24

3. Treatment option 1, Branemark approach
4 or 6 implants betw. mental foraminae & distal cantilever off each side to replace posterior teeth (5)
Carl Misch; Dental implant prosthetics; 2ed; Ch. 24

4. Treatment option 1, Branemark approach
The anterior arch form (square, oval, tapered) is related to the anterior most implant position
The foraminae position affects the position of distal most implants

5. A-P distance of greater than 8 mm A-P distance of 6 to 8 mm
The ovoid arch form often has an A-P distance of 6 to 8 mm. A square arch form often has an A-P dimension of 2 to 5 mm. A tapered arch form has the greatest A-P distance, larger than 8 mm.
A-P distance of 2 to 5 mm

6. Mental foramenae may be located as far anterior as just distal to the canine (more common in white women) and as far distal as the mesial of the first molar apex (more often in black men).
Cutright B, Quillopa N, Shupert W, et al. An anthropometric analysis of key foramina for maxillofacial surgery. J Oral Maxillofac Surg. 2003;61:354–357.

7. Treatment option 1, Branemark approach
For five anterior implants in anterior mandible, cantilever should not exceed 2 times A-P spread, with all other stress factors being low
A cantilever rarely indicated on 3 implants, even with simillar A-P spread as 5 implants
If the stress factors are high: ( parafunction, crown height, masticatory musculature dynamics) , cantilevering may be contraindicated
Narrow implants are not designed to support cantilevers

8. Treatment option 1, Branemark approach
Reserve this option for patients with low force factors (older female, wearing upper denture, abundant anterior bone, CHS to 15 mm, tapered or ovoid mandibular arches, & posterior segments of inadequate height for endosteal implant)

9. Treatment option 2
A slight variation of Branemark protocol to place additional implants above mental foraminae

10. Treatment option 2
A prerequisite available bone in height and width over foraminae
A minimum recommended implant height of 9 mm & a greater diameter of an enhanced surface area recommended
the most distal implant bears the greatest load when loads are placed on the cantilever

11. Treatment option 2 advantages
No. of implants may be increased to as many as 7
A-P spread for implant placement is greatly increased
Length of cantilever is reduced
Key implant positions: second premolars, canines, centeral incisor or midline position

12. Treatment option 3 One posterior segment connected to anterior segment
key implant positions first molar (on one side), bilateral 1st premolars, bilateral canines
Secondary positions second premolar on same side as molar implant, central incisor (midline)

13. Treatment option 3 Option 3 is better than 1 & 2:
A-P spread 1.5 to 2 times greater
When force factors are greater, 6 or 7 implant may be used (5 implant between foraminae & one or two implant distal on one side)

14. Treatment option 3
One piece casting can be fabricated & one cantilever to opposite side of molar implant would replace those posterior teeth
Requires available bone in at least one posterior region

15. Treatment option 4
Bilateral posterior implants that they are not splinted together
Key implant positions:
First molars, first premolars, canines
Secondary implant positions second premolars and/or incisor
Segmentation of the complete arch prosthetic rehabilitation has been proposed to improve ease of fabrication and maintenance issues.

16. advantages: Disadvantages Elimination of cantilever
Treatment option 4
advantages:
Elimination of cantilever
Risk of uncemented restorations & occlusal overload reduced
Prostheses has two segments rather than one
If the prostheses requires repair , the affected segment may be removed easily
Disadvantages
1. Need for abundant bone in both posterior region
2. Additional cost

17. Treatment option 4 is selected :
When force factors are great or bone density is poor
When the body of mandible is division C-h & subperiosteal or disc like implants are used for posterior

18. Treatment of choice when force factors are severe
Treatment option 5
Treatment of choice when force factors are severe
Three independent prostheses

19. Treatment option 5 Advantages: Disadvantages:
Smaller segments for individual restorations
Most flexibility and torsion of mandible
Disadvantages:
Greater number of implants required
Available bone needs are greatest

20. Treatment option 5
Most common scenario for option 5 is when posterior mandible is C-H bone volume & a circumferential subperiosteal or disc-design implant is used as second premolar & first molar

21. Other configurations

22. Other configurations

23. Implant Supported Fixed Prostheses Edentulous Mandible
Minimum requirements from biomechanical perspective:
Four or more implants
Minimum 1 cm of A—P spread
Posterior cantilever should be limited to 2 times the A-P spread

24. Edentulous Maxilla

25. Implant Supported Fixed Prostheses Edentulous Maxilla
Minimum requirements from biomechanical perspective:
Six or more implants
Minimum 2 cm of A—P spread
Posterior cantilever should be imited to ½ times the A-P spread

26. Key implant positions
From 7 to 10, with at least 3 implants from canine to canine
The ideal seven-implant positioning for a maxillary edentulous arch includes at least one central incisor position, bilateral canine positions, bilateral second premolar sites, and bilateral sites in the distal half of the first molars. In case of heavy stress factors, an additional anterior implant and bilateral second molar positions (to increase the anterior-posterior distance) may be of benefit.
In the case of heavy stress factors, an additional anterior implant and bilateral second molar positions (to increase the anteroposterior distance) may be of benefit
Carl Misch; Dental implant prosthetics; 2ed; Ch. 25

27. The dentist may use the following guidelines for implant locations in a completely edentulous maxilla:
1. The bilateral canine position is a key implant position and is planned for 4-mm-diameter implants.
2. The center of the first premolar is planned 7 to 8 mm distal from the center of the canine implant (for a 4.0-mm-diameter implant). This is an optional implant site when parafunction is moderate to severe.
3. The center of the second premolar is 7 to 8 mm distal from the first premolar site (14 mm from the midcanine position) on each side for a 4.0-mm-diameter implant. This is a key implant position.
4. The distal half of the first molar is 8 to 10 mm distal from the mid second premolar implant (this places the implant in the distal of the first molar and increases the A-P distance). Ideally, the implant should be 5 to 6 mm in diameter. This is a key implant position. When a 4-mm diameter is used, the first implant is 7 to 8 mm from the mid second premolar site, and the second implant is 7 to 8 mm more distal than the first implant.
5. The center of the second molar is 8 to 10 mm distal from the center of the first molar implant. This position is most important for the edentulous arch with a tapered dentate arch form, D4 bone types, or severe force factors.
Carl Misch; Dental implant prosthetics; 2ed; Ch. 25

28. Arch Form Square, ovoid, and tapering
Carl Misch; Dental implant prosthetics; 2ed; Ch. 25

29. Anterior Cantilever (mm) Number of Implants Implant Position
Arch Form
Anterior Cantilever (mm)
Number of Implants
Implant Position
Square
<8 2
Canines
Ovoid
8-12 3
Two canines and one incisor
Tapering
>12 4
Two canines and two incisors
Carl Misch; Dental implant prosthetics; 2ed; Ch. 25

30. Premaxilla Arch Form vs No. of implants
Carl Misch; Dental implant prosthetics; 2ed; Ch. 25

31. Other configurations

32. Other configurations

33. Other configurations

34. Other configurations

35. Implant Supported Fixed Prostheses Edentulous Maxilla
Minimum requirements from biomechanical perspective:
Six or more implants
Minimum 2 cm of A—P spread
Posterior cantilever should be imited to ½ times the A-P spread

36. Review of related literature (edentulous mandible)
Treatment with mandibular IFCDPs yields high implant and prosthodontic survival rates (more than 96% after 10 years).
Rough surface implants exhibited cumulative survival rates similar to the smooth surface ones in the edentulous mandible.
Implant fixed complete dental prostheses (IFCDPs). The one-piece prosthetic design with incorporation of posterior cantilevers into mandibular IFCDPs was the most common in this systematic review . The time period extended from January 1980 up to December 2011.
Papaspyridakos et al. Implant and Prosthodontic Survival Rates with Implant Fixed Complete Dental Prostheses in the Edentulous Mandible after at Least 5 Years: A Systematic Review Clinical Implant Dentistry and Related Research, Volume 16, Number 5, 2014

37. Review of related literature (edentulous mandible)
The number of supporting implants and the anteroposterior implant distribution had no influence on the implant survival rate.
The prosthetic design, the veneering material, and the retention type had no influence on the prosthodontic survival rates.
The loading protocol also had no influence on the prosthodontic survival rates.
Papaspyridakos et al. Implant and Prosthodontic Survival Rates with Implant Fixed Complete Dental Prostheses in the Edentulous Mandible after at Least 5 Years: A Systematic Review Clinical Implant Dentistry and Related Research, Volume 16, Number 5, 2014

38. Review of related literature (edentulous mandible)
A recent meta-analysis showed that technical complications are frequently encountered with IFCDPs during 5 to 10 years of clinical function.
The 10-year cumulative rate of “prosthesis free of complications” of 8.6% reported in that review opitomizes the advantage of retrievability of screw-retained IFCDPs vs cement-retained metal-ceramic IFCDPs.
Technical complications after the definitive prosthesis placement may not lead to implant loss but can result in an increased number of repairs and maintenance sessions.
The presence of cantilevers in mandibular IFCDPs had no influence on the prosthesis survival
Papaspyridakos P, Chen CJ, Chuang SK, Weber HP, Gallucci GO. A systematic review of biologic and technical complications with fixed implant rehabilitations for edentulous patients. Int J Oral Maxillofac Implants 2012; 27: 102–110.

39. Review of related literature (edentulous mandible)
The insertion of four implants for a fixed restoration in the edentulous mandible reveals satisfying results. However, it has to be noticed that five or more implants showed a slightly better outcome.
Kern et al. A systematic review and meta-analysis of removable and fixed implant supported prostheses in edentulous jaws: post-loading implant loss. Clin. Oral Impl. Res. 00, 2015, 1–22

40. Review of related literature (edentulous maxilla)
Implants with rough surfaces showed a statistically higher survival rate than machined implants at all intervals.
Implants placed in augmented bone had a statistically lower survival rate, except for rough-surface implants, for which no statistical difference between augmented and non-augmented bone survival rates was found.
Machined implants showed a stable survival rate only when placed in native bone.
When machined implants were placed in augmented bone, the survival rate decreased significantly at each study endpoint.
Lambert FE,Weber HP, Susarla SM, Belser UC, Gallucci GO. Descriptive analysis of implant and prosthodontic survival rates with fixed implant-supported rehabilitations in the edentulous maxilla. J Periodontol 2009; 80:1220–1230.

41. Review of related literature (edentulous maxilla)
The prosthetic design, veneering material, and the number of prostheses per arch had no influence on the prosthodontic survival rate.
Implant number and distribution along the edentulous maxilla seemed to influence the prosthodontic survival rate.
Lambert FE,Weber HP, Susarla SM, Belser UC, Gallucci GO. Descriptive analysis of implant and prosthodontic survival rates with fixed implant-supported rehabilitations in the edentulous maxilla. J Periodontol 2009; 80:1220–1230.

42. Review of related literature (edentulous maxilla)
The insertion of six or more implants for a fixed reconstruction in the maxilla reveals favorable results.
Considering the “all-on-4” concept for the maxilla, one study (Crespi et al. 2012) with an acceptable level of evidence was found, revealing a satisfactory outcome.
Kern et al. A systematic review and meta-analysis of removable and fixed implant supported prostheses in edentulous jaws: post-loading implant loss. Clin. Oral Impl. Res. 00, 2015, 1–22

43. Review of related literature
Implants with fixed prostheses show slightly but significantly better results than removable prostheses regarding both jaws.
Rough-surfaced implants demonstrated favorable results compared to machined implants.
Kern et al. A systematic review and meta-analysis of removable and fixed implant supported prostheses in edentulous jaws: post-loading implant loss. Clin. Oral Impl. Res. 00, 2015, 1–22

44. Thank you for your attention!