The influence of initial defect morphology of alveolar ridge on volumetric change of grafted bone following guided bone regeneration in the anterior maxilla region: an exploratory retrospective study.

BACKGROUND

This study aimed to explore the influence of initial ridge defect morphology on the outcome of guided bone regeneration (GBR) in the anterior maxilla region.

METHODS

Cone beam computed tomography (CBCT) examinations of patients who participated in a previous randomized controlled trial were used to assess linear and volumetric changes of bone grafts (LCB and VCB) from immediately (T0) to 6 months (T1) after surgery. The three-dimensional (3D) surface rendering of the initial defect was reconstructed, and morphological variables were defined in mesial-distal, buccal-lingual, and coronal-apical directions. The Spearman correlation, logistic regression model, and receiver operating characteristic (ROC) analyses were used to assess the possible association between initial defect morphological variables and VCB.

RESULTS

A total of 62 eligible patients were included in this study. The median value of LCB was less than 20% at different levels, while the corresponding value of VCB was 52.0%. The Spearman correlation analysis showed that the standard deviation of buccal-lingual distance (BL) was negatively associated with VCB (r=-0.315, P=0.013), whereas the ratio of maximum coronal-apical/mesial-distal distance (R) was positively related to VCB (r=0.607, P<0.001). The multivariate regression analysis revealed that the prognosis effect of BLSD (OR: 0.220, 95% CI: 0.074 to 0.655, P=0.0047) and R (OR: 7.045, 95% CI: 2.361 to 21.024, P=0.0017) remained significant. ROC curve analysis showed that R could be used to correctly classify VCB in 78.9% patients and BLSD in 71.0% of patients, as classified by the median of VCB. The discrimination value of BLSD and R revealed the areas under curve (AUC) of 0.71 (95% CI: 0.545 to 0.883) and 0.74 (95% CI: 0.573 to 0.913), respectively.

CONCLUSIONS

Within the limitations of this study, the present data confirmed the effect of initial ridge morphology on the GBR outcome in the anterior maxilla region. Specifically, a defect morphology with more BLSD and/or lower R may significantly decrease the resorption amount of grafted bone.