Individual “alveolar phenotype” limits dimensions of lateral bone augmentation

Abstract

Aim Alveolar ridge resorption following tooth extraction often renders a lateral bone augmentation inevitable. Some patients, however, suffer from severe early (during graft healing, Eres) and/or late (during follow‐up, Lres) graft resorption. We explored the hypothesis that the “individual phenotypic dimensions” may partially explain the degree of such resorptions. Materials and Methods Patients who underwent a guided bone regeneration (GBR) procedure were screened for inclusion according to the following criteria: (1) a relatively symmetrical maxillary arch; (2) an intact contra‐lateral alveolar bone dimension; (3) the availability of a pre‐operative cone‐beam CT (CBCT); (4) a CBCT taken immediately after GBR, and (5) at least one CBCT scan ≥6 months after surgery. CBCT scans from different timepoints were registered and imported into the Mimics software (Materialise, Leuven, Belgium). Bone dimensions of the contra‐lateral site of the augmentation, representing the “individual phenotypical dimension (IPD) of the alveolar crest”, were superimposed on the augmented site and registered accordingly. As such, Eres and Lres could be measured over time, in relation to the IPD (in two dimensions; per millimetre apically from the alveolar crest, in the centre of the GBR), as well as in three dimensions (the entire GBR, 2 mm away from the mesial, distal, and apical border for standardization). Results A total of 17 patients (23 augmented sites) were included. After Eres, the outline of the augmentation was in general located ±1 mm outside the IPD, but ≥1.5 years after GBR, it further moved towards the IPD (85% within 0.5 mm distance). Conclusions Within the limitations of this study, the results indicate that the dimensions of a lateral bone augmentation are defined by the “individual phenotypic bone boundaries” of the patient.

Defect angle as prognostic indicator in the reconstructive therapy of peri‐implantitis

“…Interestingly, data suggested that deeper defects with narrower baseline radiographic defect angles (DAs) exhibit more favorable reconstructive outcomes 14 . This is consistent with data derived from guided bone regeneration in alveolar deficiencies, where individual phenotypic dimensions and the buccal DA are key to understand the predictability of regenerative procedures 15,16 . In the arena of reconstructive therapy for the management of peri‐implantitis, however, the influence of the DA upon the outcomes is yet unexplored.…”

“…In fact, it was found that in cases of a crest angulation of <150°, the horizontal bone gain was ∼4, whereas in scenarios presenting crest angulation >150°, the gain was ∼3 mm lesser. More recently, Quirynen and colleagues 16 demonstrated the existence of individual alveolar phenotypes to predict horizontal ridge augmentation using 3‐dimensional virtual reconstruction and superimposition of CBCT data, with the contralateral ridge dimensions as reference. One possible explanation for this finding is the stability of the coagulum and the material that provides the barrier membrane in a contained defect in contrast to a flat architecture.…”

“…14 This is consistent with data derived from guided bone regeneration in alveolar deficiencies, where individual phenotypic dimensions and the buccal DA are key to understand the predictability of regenerative procedures. 15,16 In the arena of reconstructive therapy for the management of periimplantitis, however, the influence of the DA upon the outcomes is yet unexplored. Accordingly, the aim of this study was to analyze the influence of peri-implantitis bone defect-related features on the clinical resolution and radiographic bone gain of reconstructive therapy.…”

Efficacy of biomaterials for lateral bone augmentation performed with guided bone regeneration. A network meta‐analysis

“…74 Interestingly, a recent study indicated that the "individual phenotypical dimension" (which represents the natural alveolar crest contour before tooth loss) may be a predictor of how much buccally one can regenerate bone when applying the GBR concept. 75 Hence, over-augmentation beyond the boundary line of the bony envelope may not be a successful strategy.…”

Simultaneous or staged lateral ridge augmentation: A clinical guideline on the decision‐making process

“…It is worth noting that bone resorption after LRA can vary based on the patient's individual phenotype dimensions, as observed in a study comparing the healthy contra-lateral site of the LRA. 47,111 This highlights the importance of considering over-engineering during LRA. 47 • Therefore, it is critical to follow a workflow that ensures predictable long-term biological and esthetic outcomes in all scenarios.…”