Ridge Splitting

Management of the narrow edentulous ridge is a challenge that all implant surgeons face. Traditional procedures for ridge enhancement with these cases include autogenous and allogeneic bone grafting and GBR. Ridge expansion can also be used in preparation for bone augmentation with and without simultaneous implant placement. Hilt Tatum is given credit for working with ridge expansion protocols in the 1970s.

The protocol at the time included tapered channel formers, D-shaped osteotomes, and custom implants.65 Several advancements in implant dentistry and surgical instrumentation have further facilitated this tech- nique. More commonly today the use of the Piezosurgery device has been favored to ease ridge splitting with more control and safety. Long-term results with excellent main- tenance of ridge width have been well documented with excellent success rates. Scipioni et al reported a 98% 5-year implant survival rate when utilizing ridge expansion with simultaneous implant placement.66 Summers et al further showed a 96% implant survival rate in 143 maxillary implant osteotome cases utilizing this technique. Sethi and Kaus performed ridge expansion in 150 patients (449 implants total) and demonstrated a 97% survival rate at 5 years.

Lustmann and Lewinstein demonstrated a number of key elements to ridge expansion techniques with simultane- ous interpositional bone grafting.69 Because the grafting is performed intraosseously, a more predictable technique with favorable wound healing was reported with abundance in vasculature and osteogenic cells coming from the marrow, favoring graft incorporation. Staged implant placement is recommended after 4 to 5 months as opposed to 7 months with the use of rhBMP-2.Therefore, the treating clinician must carefully select cases appropriately.

Indications for ridge expansion
• Narrow alveolar ridge (minimum 2+ mm, marrow component)
• Primarily maxillary sites greater than one tooth
• If in the mandible, only posterior distal-extension eden- tulous sites with a marrow component
• Adequate alveolar bone height (approximately 10 mm minimum)

Contraindications for ridge expansion
• Inadequate alveolar bone height
• Concavities or undercuts of ridge
• Fused cortices (no marrow)
• Less than 2-mm ridge width
• Single-tooth sites

Key points
One key point that needs to be addressed is that ridge expan- sion and simultaneous implant placement in the maxilla typically result in an exaggerated facial implant inclination because the implant osteotome follows the denser palatal bone. Factors to consider include interocclusal space and biomechanical force factors (especially parafunction).While the advantages of the ridge splitting technique include faster healing, the treating clinician must always weigh the pros and cons because ridge split failure can also occur and result in catastrophic bone loss.

Surgical protocols for maxillary ridge expansion and interpositional bone grafting are routinely performed via intravenous sedation in my practice. Figures 4-32 and 4-33 demonstrate two cases utilizing ridge splitting.A midcrestal incision is made within keratinized gingiva with reflection of the mucoperiosteal flap. Thin straight osteotomes for initial crestal penetration may be utilized along with rotary burs and/or a Piezosurgery device. In general, the author’s personal preference is ridge expansion with interpositional bone grafting and delayed implant placement as opposed to simultaneous implant placement. Furthermore, this tech- nique is more suitable for the maxillary arch because of its more cancellous nature (ie, lower bone density). Figure 4-34 demonstrates another ridge split case performed in the posterior mandible.

 

Use of osseodensification to expand ridge dimension during a ridge split technique
Osseodensification, presented primarily in chapter 5, has also been utilized in conjunction with the ridge split technique (Fig 4-35). During such cases, a bone void is typically encountered on the mesial and distal aspects of the implants. While the use of grafting materials within the ridge expansion has been controversial, one element that may certainly assist the clinician in both maintaining adequate bone volume within the osteotomy site and helping to increase primary stability of the implants is the use of osseodensification.