Estimating the occurrence of labial bone perforation and implantation into the maxillary sinus maxillary premolars based on the morphology of maxillary premolars: A clinical study

Abstract Objectives The purpose of this study was to investigate the occurrence of labial bone perforation (LBP) and implantation into the maxillary sinus between various tooth-alveolar classifications with respect to the crown axis in maxillary premolars. Material and methods Cone beam computed tomography (CBCT) of 399 participants were analyzed to determine the probability of LBP and implantation into the maxillary sinus when associated with variables that included tooth position and tooth-alveolar classification. Results The morphology in the maxillary premolars was classified as straight, oblique, or boot-shaped. The first premolars were 62.3% straight, 37.0% oblique, and 0.8% boot-shaped and LBP occurred in 4.2% straight, 54.2% oblique, and 83.3% boot-shaped first premolars when the virtual implant was 3.5×10 mm. When the virtual implant was 4.3×10 mm, LBP occurred in 8.5% , 68.5% and 83.3% first premolars, respectively. The second premolars were 92.4% straight, 7.5% oblique, and 0.1% boot-shaped and LBP occurred in 0.5% straight , 33.3% oblique, and 0% boot-shaped, respectively, when the virtual implant was 3.5×10 mm; and LBP occurred in 1.3%, 53.3% and 100% second premolars, respectively, when the virtual implant was 4.3×10 mm. Conclusions When an implant is placed in the long axis of a maxillary premolar, the tooth position and tooth-alveolar classification should be considered when assessing the risk of LBP. Attention should be paid to the implant direction, diameter, and length in the oblique and boot-shaped maxillary premolars. Clinical relevance Preoperative CBCT needs to be used to reduce LBP in the maxillary premolars, especially when oblique or boot-shaped.