1. Ridge Splitting Techniques
By David R. Telles, DDS Diplomate of the American Board of Oral and Maxillofacial Surgeons

2. Introduction Not a well documented procedure
Technique useful for expansion of horizontal width deficiency
Historically
Indications
Block Grafting vs. Ridge split
Literature review

3. Available Techniques Bone grafting Guided bone regeneration
Distraction osteogenesis
Expansion of the existing residual ridge
AKA ridge splitting, bone spreading, ridge expansion, or the osteotome technique

4. Ridge Split Depends on numerous variables Clinical training
anatomic region
degree of atrophy
arch relationships
Prosthetic goals
esthetic demands
Economics
healing time requirements

5. Historically
Ridge splitting for root-form implant placement was developed in the 1970s by Dr. Hilt Tatum
Tatum developed specific instruments including tapered channel formers and D-shaped osteotomes to expand the resorbed residual ridge
Designed an implant system (Omni R system, St. Petersburg, Florida) for this technique that was tapped into place with a mallet.
Summers later revived the interest in this technique
developed round implant osteotomes suitable for use with commercially available cylinder root-form implant systems
reported that in 143 maxillary implants placed using the osteotome technique, only 5 failed
Scipioni et al published their experience with the edentulous ridge expansion technique
329 implants in 170 patients with narrowed residual ridges
Following a 4 to 5 month healing period and 3 to 5 months of provisional loading, the implants were restored
98.8% implant survival over 5 years.

6. Historically
Sethi and Kaus evaluated the ridge expansion technique in thin maxillary ridges with adequate height and two cortical plates separated by a cancellous layer of bone
placed 449 implants at the time of expansion in 150 patients
97% implant survival rate after a 5-year observation period
Clinical studies have shown that surgeons may achieve predictable results in managing the narrow edentulous ridge with ridge splitting techniques
treatment has become an integral part of implant surgical therapy

7. Indications
used to expand the edentulous ridge for implant placement or insertion of an interpositional bone graft
only suitable for enhancing ridge width – must be adequate done height – no vertical bony defect can be present
minimum ridge width of 3.0 mm is preferred
Splitting ridges narrower than this is technique sensitive and can result in bone fractures and resorption
Very Difficult to expand narrow ridges in single tooth sites – these cases better augmented with graft
Avoid ridge splitting when facial bone concavities are present

8. Indications More applicable to the maxilla than the mandible
Thinner cortical plates and softer medullary bone make maxillary ridge splits more predictable
In some cases narrow posterior mandible may be split
E.g. long edentulous span
Abundant bone height superior to the mandibular canal (> 12 mm)
Presence of some cancellous bone between the dense outer cortical plates
If these conditions are not met may be best to consider onlay augmentation
Bone quality dictates outcome

11. Following tooth loss….
thin buccal cortex of the maxillary alveolus resorbs to a greater degree than the thicker palatal socket wall
resorption results in a decrease in bone width and more medial position of the residual ridge
narrower ridge in the anterior maxilla and premolar areas is often inadequate for placement of standard-diameter dental implants (4.0 mm)
When Ridge splitting considered– do not compromise on the desired implant diameter simply for implant placement
Goal = expand the ridge to allow placement of the appropriate size implant for proper prosthetic / biomechanical support

12. Considerations Interocclusal space
r/o unfavorable crown-to-implant ratios
Ridge splitting doesn’t correct ridge discrepancies
If significant medial resorption has occurred – causing an unfavorable ridge relationship – consider only grafting
When implants are placed following ridge splitting – angulation is typically more facial compared to the axis of natural teeth
Due to greater remodeling and resoprtion of the facial cortical plate following extraction
Restoring these may require angle abutments – communicate to GP

13. Advantage over Grafting
Ridge splitting may allow for immediate implant placement
Unlike guided bone regeneration, which relies on bone forming over the exposed implant surface, ridge splitting repositions the cortical plates around the implant. Bone then regenerates within the space between the expanded cortical plates
Diminished treatment length
Cost for implant treatment is decreased
No bone grafting or barrier membranes required
DisAdv:
If complications arise and bone loss occurs – pt may be left with an even more greater bone defect

14. Evaluation / Technique
Periapical Eval
Panorex
--- help to determine bone height
CT scan –
Use of a radiographic stent can guide placement and give information regarding ridge deficiency
Helps to determine actual ridge width and deficiencies
Determine if cortices have fused
Palpation / Ridge mapping – to determine the depth/thickness of soft tissue
Soft tissue considerations – adequate attached gingiva
Study models – interocclusal distance

16. Technique
Minimal mucoperiosteal flap reflection is performed to expose only the ridge crest
periosteum along the lateral cortices should remain intact to ensure blood supply to the underlying bone
Evaluate the ridge width and determine whether the bone dimensions and anatomy are suitable for ridge splitting
If necessary, the peak of the thin ridge may be slightly reduced with a ronguer or osteoplasty bur
round-handled scalpel with a No. 15 or round-tip Beaver blade is used to begin the osteotomy
osteotomy should bisect the ridge and separate the cortical plates
A mallet is used to advance the scalpel blade through the bone
Hold blade parallel to the palatal or lingual cortex – will often result in a more facial angulation
Remove blade with a back and forth motion parallel to the cut
This crestal bone cut can be within 1 mm of the adjacent tooth
The ridge split should be performed well beyond the planned implant sites in an edentulous span

17. Technique
After the crestal osteotomy is completed, thin chisels, osteotomes, tapered fissure burs, or saws are used to further separate the cortices and begin the ridge expansion
In dense bone, a thin, tapered fissure bur or a saw blade is often preferred to complete the bony cut
Gradually, wider chisels or osteotomes are used to gently expand the ridge
If bone expansion is difficult, then vertical osteotomies may be made through the facial cortex at each end of the crestal osteotomy
Implant site preparation can be accomplished using round, tapered implant osteotomes or implant drills
Slowly place implant to allow for expansion
Some ppl perfer to place particulate bone graft around the implants and between separated cortices – usually unnecessary
Follwing implant placement – split thickness facial flap developed leaving the periosteum in tact – will allow for advancement of the flap for primary closure
Wait 3-6 months to allow for adequate implant / bony healing

19. Technique - osteotome
When greater ridge width is present and minimal gains required – implant osteotome technique may be considered
Useful in anterior and posterior maxilla
OR indicated when ridge width is adequate but clinician wants to place wider diameter implant (>4.5 mm) for improved emergence profile or biomechanical

20. Technique -- osteotome
A small, round bur is used to penetrate the crestal bone slightly palatal to the center of the ridge.
implant osteotomy is started with a small-diameter drill (1.5–2.0 mm)
shank of the drill is angulated slightly facially to follow the palatal cortical bone
palatal cortex is more difficult to expand
help prevent apical perforation of the tip through the facial cortex
A Linderman bur is also useful for the initial preparation because it is side cutting, and palatal pressure during drilling can prepare the denser palatal bone
Tapered implant osteotomes in gradually greater diameters are then used to prepare the implant site
Gently malleted to compress and expand the bone as opposed to removing it with a drill.
force should be directed over the long axis of the osteotome w/ periodic pauses allow the viscoelastic bone to adapt to the expansion
The osteotome should be rotated with a gentle pulling force to allow atraumatic removal
Digital pressure on the facial plate can help support the bone during preparation and detect apical perforation of the osteotome or drill.

21. Technique -- osteotome
A screw tap may be needed in denser bone (type II) and to prepare the thicker palatal cortex
Before implant insertion, a depth gauge or periodontal probe is used to detect any perforation of the facial cortex
If a fenestration or dehiscence is noted, then an incision can be made through the mucosa over the site and the tissues can be reflected to expose and repair the defect.

23. Review
Clinical experience has shown that the ridge splitting technique can be a useful method for managing the narrow residual ridge
Careful preparation of the bone and maintenance of an attached periosteum are critical to the formation of new bone around the interproximal surfaces of the implants.
Wound healing in these cases is similar to the fracture repair of bone

24. Review
The risk of complications with ridge splitting increases when treating very thin ridges or denser inflexible cortices.
Failure with this technique can result in significant bone loss
If significant cortical bone fractures occur or the facial plate separates at the base, then the implant should not be placed.
bone graft materials such as particulate bone or cortical struts may be inserted within the osteotomy for a staged reconstruction of the ridge
fractured facial plate should be stabilized with a screw or miniplate
Recommendation by Misch – sedation or GA

25. Techniques on the rise
Utilization of Distraction osteogenesis techniques
After the ridge split – device is inserted to control horizontal expansion
Latency of 5-7 days
Then the device is activated – segment is distracted 1.0 mm per day until the desired ridge width is achieved
Consolidation period of 8 weeks – device removed and implants placed
Healing time is less than onlay bone grafting
Does not allow simultaneous implant placement

26. Summary
Ridge splitting techniques are useful for managing the narrow edentulous ridge for implant placement or interpositional bone grafting
Surgical approach may be used in both jaws -- best suited for the maxilla
Limited to treating ridge width deficiency
cortical plates of the residual ridge must be carefully split while maintaining periosteal attachment
Allows simultaneous implant placement
Proper patient evaluation and case selection is essential to achieving a successful surgical and prosthetic outcome

27. References
Sethi A, Kaus T. Maxillary ridge expansion with simultaneous implant placement: 5-year results of an ongoing clinical study. Int J Oral Maxillofacial Implants 2000;15:491– 9.
Misch CM. Ridge augmentation using mandibular ramus bone grafts for the placement of dental implants: presentation of a technique. Prac Periodont Aesth Dent 1996;8:127 – 35.
Misch CM. Comparison of intraoral donor sites for onlay grafting prior to implant placement. Int J Oral Maxillofacial Implants 1997;12:767– 76.
Misch CM. The use of the mandibular ramus as a donor site for onlay bone grafting. J Oral Implantol 2000;26:42 –9.
Pietrokovski J, Massler M. Alveolar ridge resorption following tooth extraction. J Prosthet Dent 1975;17: 21–7.
Mecall RA, Rosenfeld AL. The influence of residual ridge resorption patterns on fixture placement and tooth position in the partially edentulous patient. Part III. Presurgical assessment of ridge augmentation requirements. Int J Periodont Rest Dent 1996;16:323– 37.
Misch CE. Divisions of available bone. In: Misch CE, editor. Contemporary implant dentistry. St. Louis (MO): Mosby; p. 98– 9. [11] Triplett RG, Schow SR.
Summers RB. The osteotome technique: part 4—future site development. Comp Cont Ed Dent 1995;16: 1090– 9.