Retrospective Radiographic Analysis and Treatment Outcomes of Patients With Congenitally Missing Maxillary Lateral Incisors
Replacing congenitally missing teeth can be challenging due to anatomical limitations. This retrospective radiographic study aimed to evaluate (1) the dimensions of the alveolar ridge in congenitally missing maxillary lateral incisor sites and (2) whether straightforward implant placement and placement in a prosthetically ideal position was possible. CBCT images of the maxillary alveolar ridge were measured at 3, 8, and 13 mm from the planned crown margin in a labio-palatal and mesio-distal dimension. Virtual implant planning was completed in 3D planning software to evaluate whether the straightforward placement of a 3-mm wide and 10-mm long implant (with 1.5 mm safety distance to neighboring teeth; 1 mm bone wall on the buccal and palatal aspect of the implant) was possible in a prosthetically driven position. Twenty-three patients with 39 missing maxillary lateral incisors were analyzed. The mean (SD) of the alveolar ridge labio-palatal width was varying, 4.6 mm (1.3) at 3 mm, 5.6 mm (1.2) at 8 mm, and 7.8 mm (1.9) at 13 mm. Radiologically straightforward implant placement was possible in 56.4% (n = 22) of the sites. In 5 sites (22.7%) where straightforward implant placement was possible, the implants could be planned in a prosthetically driven position. According to patient records, straightforward implant placement was performed in 33.3% (n = 13) of the cases, 5 of them in prosthetically driven position. In congenitally missing maxillary lateral incisor sites, the alveolar ridge width is limited in the labio-palatal direction and might affect the possibility of straightforward and prosthetically driven implant placement.
Description of the measurements: (a) The labio-palatal width of the alveolar process was measured perpendicular to the alveolar process at 3 mm, 8 mm, and 13 mm from the planned labial crown margin. In the case of an alveolar ridge located more than 3 mm away apically to the crown margin, the first measurement was not applicable. (b) The mesiodistal width of the edentulous site was measured from the root surfaces of the neighboring teeth at 3 mm, 8 mm, and 13 mm apically to the planned labial crown margin. The labio-palatal measurement in this figure (I) is done at 8 mm apically to the planned crown margin (marked with green line in image on the right-hand side). (c) The implant was virtually placed on the edentulous site in a planning software (SMOP, Swissmeda). The angle between the implant placed in the actual anatomical alveolar ridge (blue implant) and the ideal prosthetic position (pink implant) was measured.
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