Relationship of the maxillary posterior teeth and maxillary sinus floor in different skeletal growth patterns: A cone-beam computed tomographic study of 1600 roots

Purpose@#This study evaluated the distance from the posterior root apices to the maxillary sinus floor (MSF) and the frequency of roots touching or protruding through the MSF using cone-beam computed tomography (CBCT). @*Materials and Methods@#This study included 100 subjects divided into different vertical and anteroposterior skeletal growth patterns. On CBCT images, the distance from the posterior root apices to MSF was measured and the frequency of roots touching or protruding through the MSF was evaluated using NNT software (version 5.3.0.0; ImageWorks, Elmsford, NY, USA). @*Results@#No statistically significant differences were found in the distance from the posterior root apices to the MSF among vertical skeletal groups (P>0.05). The palatal roots of the first molar and the palatal, mesio-buccal and disto-buccal roots of the second molars had significantly less distance from MSF in skeletal class II than in class III (P<0.05). The high-angle group had the highest frequencies of roots touching or protruding into the maxillary sinus (49.8%); the lowest proportion of these roots was found in skeletal class III (28.3%) and the highest proportion in class II (50.3%). Males had shorter distances from the posterior root apices to the MSF and higher frequencies of roots protruding through or touching the MSF than females. @*Conclusion@#Anteroposterior skeletal growth patterns and sex affected the distances from the maxillary posterior roots to the MSF. The frequency of roots protruding into or touching the sinus was affected by both vertical and anteroposterior skeletal groups and sex. These findings have implications for dental practice.

Clinical use of ridge-splitting combined with ridge expansion osteotomy, sandwich bone augmentation, and simultaneous implantation.

Our aim was to describe and evaluate the outcome of ridge-splitting and simultaneous implantation combined with ridge expansion osteotomy and sandwich-bone augmentation in the aesthetic zone. Thirty-one patients aged from 21-55 years who presented with narrow edentulous ridges (2.88∼5.08mm) were treated by ridge-splitting together with ridge expansion osteotomy and sandwich-bone augmentation to correct the osseous deficiency for simultaneous implantation. Bicon(®) implants were used. Calipers were used for biometric evaluation of the width of the ridge at both the first and second operations. Cone-beam computed tomography (CT, Morita, Kyodo, Japan) was used to assess the morphology of the ridge and the outcome of the operation. Forty-three implants were placed in the 31 patients selected, and none failed. At follow up all the implants functioned well and we saw no sign of gingival recession. Biometric evaluation at the surgical sites showed that the mean (SD) amount of augmentation of the ridge in the buccopalatal dimension was 2.8 (0.7) mm, p<0.01). For a narrow edentulous ridge in an aesthetic zone, ridge splitting together with ridge expansion osteotomy and sandwich-bone augmentation is a reliable technique.