Purpose: To assess the location of posterior superior alveolar artery (PSAA) using CBCT in relevance to sinus lift procedure for implant placement. Patients and Methods: A retrospective study was conducted using the CBCT data of 500 patients (n = 500). Linear measurements were carried out to localize the medio-lateral and vertical position of posterior superior alveolar artery in postero-lateral wall of maxillary sinus and its proximity to the floor of maxillary sinus using CS 3D imaging 3.7.0 software program. The relative position of PSAA was determined as; (a) intra-osseous, (b) below the membrane and (c) outer-cortex of lateral sinus wall. The location of PSAA was assessed in molar region bilaterally by using following radiographic measurement; (1) distance between the lower border of posterior superior alveolar artery and alveolar crest, (2) height from the floor of maxillary sinus to alveolar crest and (3) distance from the posterior superior alveolar artery to medial wall of maxillary sinus. Results: The prevalence of the artery was observed in 99.4% of the sinuses and was mostly intraosseous (84.2%).The mean distance between the lower border of the artery and alveolar crest is significantly higher in males compared to females (P < 0.01). The distribution of artery location did not differ significantly across various age groups (P > 0.05). Discussion/Conclusion: The most common variant of PSAA was identified in the intra-osseous region and the mean distance of the vessel to crest of the residual ridge differs significantly with gender and not with age.

Aim: The aim of the study was to investigate whether the surface geometry or topography of implant abutments affects the retentive strength of prosthesis cemented with zinc phosphate on standard machined, sandblasted, and grooved implant abutments and to compare the results between them. Materials and Methods: Fifteen similarly shaped implant abutments (MDcpk61; MIS Implant Technologies Ltd.,) (height 6.0 mm and 6-degree taper) were divided into three groups (n = 05): Group I – standard machined abutments without grooves, Group II – sandblasted abutments (same as Group I but sandblasted with 50 μ aluminum oxide), and Group III – abutment with prefabricated circumferential grooves. Further in these groups of 15 abutments, 5 abutments each are to be taken to check the retentive force of zinc phosphate cement. Fifteen identical cast copings was prepared to fit all 15 abutments. The castings will be cemented to each group of abutments with an above-mentioned luting agent. After thermal cycling and storage for 6 days in a water bath, a retention test is to be done with a tensile testing machine (Instron) (5 mm/min) and retentive forces will be recorded. Data will be subjected to one-way ANOVA test and Student's t-test. Results: For zinc phosphate cement, F = 30.53 (>3.59 for P = 0.05) shows a statistically significant difference between all the three groups. Conclusion: Circumferential grooves on implant abutments give better retention when compared with standard machined (plain) and sandblasted abutments despite marked difference. Clinical Significance: Retention of restoration depends on the surface of the abutment as well as the luting agents used. Incorporation of retentive grooves can enhance retention of prosthesis, especially in situation of short abutments.