OBJECTIVE: To examine implant stability, radiographic bone loss and periodontal clinical parameters for implants placed in conjunction with the ridge-split technique.
MATERIALS AND METHODS: Ten subjects (9 females, 1 male, average age of 48 yrs) with partial edentulism associated to horizontal ridge resorption in either the maxillary or mandibular arches were included. Inclusion criteria were non-smokers, missing at least 1-3 teeth, with a minimum of 3 mm of existing ridge width at assigned edentulous site. Exclusion criteria were smokers and systemic diseases that may affect wound healing. The ridge split technique (RST) was performed using ultrasonic bone surgery and bone chisels. Implants were immediately placed with a two-stage approach. The space between host bone and implant surface was filled with particulate bone graft. A resorbable membrane was used to isolate the wound and flaps were sutured. Pre- and post-operative ridge widths and soft tissue parameters were recorded at defined time intervals; implant stability was assessed using resonance frequency analysis (RFA). Cone Beam Computed tomography (CBCT) and conventional radiography analysis were performed prior to, at surgery and during the osseointegration period. Wound healing time prior to loading was 4.5 months ± 6 days.
RESULTS: The initial ridge width was 4.02 ± 0.55 mm. The immediate ridge width after surgery was 6.52 ± 0.63 mm. The final ridge width at the uncovery surgery (t=3 months) was 6.52 ± 0.57 mm. Total of 20 implants were placed via RST. All implants were osseointegrated. Seven implants (35%) exhibited marginal bone resorption ranging from 2 – 4 mm at the uncovery surgery (t=3 months). Initial implant stability quotient (ISQ) was 56 ± 4.3 immediately following implant placement with an observed increase to 65 ± 3.6 ISQ following osseointegration. Seventeen implants were followed up to 6 months after loading with no further changes in peri-implant clinical and radiographic parameters.
CONCLUSION: Based on the reported case series, immediate implant placement in conjunction with RST results in marginal bone loss (2 -4 mm) around 35% of the implants following 3 months of healing. Peri-implant clinical and radiographic parameters around the loaded implants exhibited no further changes. This modality of treatment should be implemented cautiously since an initial crestal bone loss is expected. Additional studies are necessary to determine various factors that may have differential effect on outcome.