Alveolar ridge bone changes in patients treated with the split-crest technique with simultaneous implant placement: A retrospective longitudinal observational study

Objectives

To investigate long-term alveolar ridge bone changes in patients treated with the split-crest technique (SCT) with simultaneous implant placement.

Materials and Methods

Alveolar ridge width (ARW) was measured with a caliper immediately before (ARW1) and after SCT (ARW2) with a caliper. Existing CBCT scans taken at least 5 years postoperatively were used to assess the healed ARW (ARWF), buccal bone thickness (BBT), and lingual/palatal bone thickness (L/PBT) at 0, 3, and 5 mm apically from implant platform level (IPL). The distance between IPL and buccal bone crest (IPL-BBC) was also measured. Findings were compared with Wilcoxon and Student's t tests (p < .05).

Results

Records of thirty patients with 85 implants were included. Eleven patients (31 implants) presented CBCT scans taken in two separate occasions, resulting in 116 measurements. Tomographic follow-up ranged from 5 to 18 years (11.5 ± 4.18 years). Mean ARW increased from 3.2 ± 0.6 to 6.6 ± 0.48 mm after SCT, but significantly reduced overtime to 4.46 ± 0.83 mm (ARWF) (p < .0001). Mean BBT was 0.5 ± 0.9, 1.3 ± 0.9, and 2.0 ± 1.2 mm, while mean L/PBT was 0.9 ± 0.7, 1.6 ± 0.9, and 2.1 ± 1.0 mm at 0, 3, and 5 mm from IPL, respectively. IPL-BBC distance varied up to 8.7 mm (1.4 ± 2.0 mm), with 56/116 measurements (51/85 implants) showing IPL-BBC = 0 mm.

Conclusion

Although SCT with simultaneous implant placement can predictably increase ARW postoperatively, ARW tended to significantly reduce over time, due to reductions in BBT and L/PBT, especially coronally. Nonetheless, 60% of the implants still presented some buccal bone at IPL.