A preliminary morphologic classification of the alveolar ridge after distraction osteogenesis

We sought to develop and evaluate a preliminary morphologic classification of the alveolar ridge after distraction osteogenesis.

Twelve patients (7 women and 5 men; mean age, 42.6 years; age range, 30 to 57 years) underwent a total of 17 alveolar ridge distractions before the placement of a total of 44 dental implants. Ridge bone morphology was evaluated and categorized at implant placement, with subsequent evaluation of the frequency and type of complications in each category.

Four morphologic categories were identified, as follows. Category I consisted of wide alveolar rim and no bone defects; 7 (41.2%) of the 17 ridges were assigned to this category, and a total of 22 implants were placed with no complications. Category II consisted of wide alveolar rim, lateral bone surface concavity; 4 (24%) of the 17 ridges were assigned to this category, and a total of 8 implants were placed, with fenestration defects being the most frequent complication (2 of 8 implants [25%]). Category III consisted of narrow alveolar rim, lateral bone surface concavity; 5 (29.4%) of the 17 ridges were assigned to this category, and a total of 13 implants were placed, with dehiscence defects being the most frequent complication (4 of 13 implants [31%]). Category IV consisted of distraction transport segment forming a bridge, without bone formed beneath, necessitating guided bone regeneration; 1 (6%) of the 17 ridges was assigned to this category, and following bone regeneration 1 implant was placed, without complications. Subcategory D consisted of lingual deviation of the distraction axis, occurring in any of categories I to IV, and when severe requiring corrective osteotomy to free and reposition the transport segment and neoformed bone; 4 (24%) of the 17 ridges were assigned to this subcategory (ie, to subcategory ID, IID, IIID, or IVD); in 1 case, the deviation was severe, requiring corrective osteotomy; in this case 3 implants were placed, without complications.

This preliminary morphologic classification of the postdistraction alveolar ridge effectively categorizes the variation observed in our patients and in our experience provides a useful basis for decision-making regarding implant placement. However, further studies are required to confirm the generality of this classification and incidences of complications in each category.