Anatomical study of palato-gingival groove in maxillary central incisors

Palatogingival groove (PGG) is a developmental anomaly affecting mainly the maxillary incisors. PGG incidence, depth, and length are clinically important because it may cause severe and localized periodontitis; and it may divide the root canal resulting in accessory foramina. This study aimedto analyze the presence, shape, length, and depth of the palatogingival groove in maxillary central incisors. 1,668 maxillary central incisors wereused. Each tooth had its root portion inspected in order to verify PGG presence and depth. The found palatogingival grooves were classified according to the system proposed by Gu [5], as follows: Type I (short and superficial), Type II (long and superficial), and Type III (long and deep). All teeth that showed the grooves were radiographed; five teeth had theirroot surface analyzed through Scanning Electron Microscopic (SEM); and four teeth corresponding to each PGG type were sent to obtain histologicalsections and then submitted to microscopic analysis. Of the 1.668 analyzed incisors, 27 (1.61%) showed the palatogingival groove: 8 (29.6%) Type I, 17 (63%) type II, and 2 (7.4%) Type III. Microscopic analysis revealed no communication between PGG and root canal. In conclusion, our results showed that PGG can be clinically and radiographically diagnosed on maxillary central incisors, with the type II being the most common. The professionalsshould be aware of the features of this groove due to its severe clinical consequences. KEYWORDSIncisor; Anatomical variation; Palatogingival groove