Abstract
BACKGROUND: Immediate implant placement is a technique-sensitive procedure, requiring precise positioning on the palatal aspect to ensure ideal prosthetic emergence and contour. Achieving primary stability is essential for the placement of an immediate provisional crown. The Inverted Co-Axis implant is uniquely designed for this purpose, featuring a 12-degree angled neck and a widened middle third, allowing central positioning within the alveolar socket while maintaining primary stability. Given its uncommon use, this study aimed to compare the performance of the Inverted Co-Axis implant with that of a conventional conical implant. MATERIALS AND METHODS: A randomized controlled trial was conducted with 30 patients, equally divided into two groups (n=15). Immediate implants were placed in the anterior maxilla, each restored with an immediate provisional crown and accompanied by connective tissue grafting during surgery. Outcomes included implant survival, success rates, primary stability (insertion torque, ISQ), bone remodeling, and aesthetic results. Statistical analysis comprised descriptive measures (mean, SD, median, quartiles) and appropriate inferential tests: Mann-Whitney U, Wilcoxon signed-rank, Student's t-test, Chi-square, Kruskal-Wallis, Spearman's correlation, and Brunner-Langer. Significance was set at α=0.05. RESULTS: All implants survived (100% survival rate). Success rates were 93.3% in the control group and 73.3% in the test group, with no statistically significant difference. Insertion torque averaged 35 Ncm (control) and 42 Ncm (test), with ISQ values between 56-62 in both groups. Minimal horizontal bone loss was observed at 1mm, 3mm and 5mm. Vertical bone loss was greater on the buccal aspect in the test group, while palatal loss was higher in the control group. Aesthetic evaluation via the Pink Esthetic Score yielded comparable results. CONCLUSIONS: Both implant designs proved effective and reliable for immediate post-extraction implantation, with favorable outcomes in stability, bone preservation, and aesthetics.