Comparing circular cortical-lamina anchoring versus split-crest technique in posterior mandible: A retrospective cohort study.

Background: This retrospective study aimed to assess the effect of horizontal bone augmentation using the circular cortical-lamina anchoring technique (CCA) and modified split-crest technique (MSC) on the knife ridge of the posterior mandible.

Methods: Patients who underwent horizontal bone augmentation in posterior mandible sites between 2018 and 2023 were reviewed and divided into MSC and CCA groups based on the procedure performed. Clinical and cone-beam computed tomography data were recorded to evaluate the horizontal bone width at 1, 3, 5, and 7 mm below the crest; buccal width change; alveolar ridge width resorption during the healing period; and keratinized mucosa change.

Results: This study examined 48 sites (CCA, 24; MSC, 24) in 39 patients (CCA, 21; MSC, 18). At baseline, there was no significant difference in alveolar ridge width between the two groups. Both groups showed significant horizontal ridge augmentation after healing (CCA: 4.25 ± 1.11 mm; MSC: 2.97 ± 0.36), and the average bone gain was more in the CCA group (p < 0.001). Both groups showed a significant horizontal bone width increase at 3 mm below the crest (CCA: 4.99 ± 1.60 mm; MSC: 3.34 ± 0.78 mm). Besides, compared with the CCA group, an increase in keratinized mucosa was observed in the MSC group after the healing period (CCA: -0.72 ± 0.36 mm; MSC: 3.40 ± 1.03 mm; p < 0.001).

Conclusion: This study demonstrated that both the CCA and MSC could achieve effective horizontal augmentation, with the CCA presenting a similar spatial maintenance ability during the healing process along with increased bone gain. Therefore, the CCA can be considered as an effective alternative to the MSC.

Clinical trial registration number: ChiCTR2400084525.

Plain language summary: This study compared two methods to widen the bone at the back of the lower jaw: circular cortical-lamina anchoring (CCA) and modified split-crest technique (MSC). We checked 39 patients who underwent these procedures from 2018 to 2023 and measured the width of the bones and the changes in soft tissue after the operations. Initially, the size of the jawbones was similar. After the operations, both groups had wider jawbones and the bones in the CCA group showed more growth (4.25 mm on average) than the bones in the MSC group (2.97 mm on average). The best results were seen at 3 mm below the top of the jawbone. Therefore, both methods can make the jawbone wider, but the CCA method seems to be better suited for growing more bone. The CCA could be a good alternative to the MSC for patients who require widening of their jawbone for implantation.