Immediate graftless rehabilitation of the posterior maxilla using digitally-guided palatonasal cortical engagement with long angled implants: A prospective 12-month pilot cohort

Abstract

Immediate implants in the posterior maxilla are often limited by reduced bone height and sinus proximity, traditionally requiring grafting. Long tilted implants engaging the palatal cortex and nasal floor may enhance stability without augmentation; however, prospective evidence for immediately loaded, digitally guided palatonasal protocols is limited. Therefore, the aim of this study was to evaluate clinical, radiographic, and patient-reported outcomes of an immediate graftless palatonasal cortical-engagement protocol using digitally guided long tilted implants for posterior maxillary rehabilitation. In this nonrandomized single-arm prospective cohort, 15 patients (25 implants) requiring immediate implants in the posterior maxilla were recruited through consecutive sampling. Following flapless atraumatic extraction, single-drill low-speed osteotomies were prepared. Implants (20–25 mm length; 3.75–4.2 mm diameter) were placed approximately 4 mm subgingivally with computer-guided trajectories (30°–45° tilt) to engage the palatal cortex and nasal floor/lateral wall. Immediate screw-retained monolithic zirconia crowns were delivered within 48 h. Primary outcomes were implant and prosthesis survival at 12 months. Secondary outcomes included marginal bone level (MBL) changes, probing pocket depth (PPD), complications, and patient-reported outcome measures (PROMs). Two blinded examiners performed radiographic assessments. Repeated-measures analysis of variance and Wilcoxon signed-rank tests were used to evaluate longitudinal changes. Statistical significance was set at P < 0.05. Implant and prosthesis survival were 100% at 12 months. Mean mesial MBL change was −0.13 ± 0.18 mm ( P < 0.05) and distal −0.18 ± 0.18 mm ( P < 0.01). PPD decreased significantly mesially (3.77 ± 0.68–2.93 ± 0.50 mm) and distally (3.83 ± 0.88–3.00 ± 0.65 mm) ( P < 0.001). PROMs indicated high satisfaction (9.60 ± 0.51), willingness to recommend (9.73 ± 0.46), and chewing comfort (9.40 ± 0.74). Postoperative pain declined significantly by day 7( P < 0.001). No surgical or sinus complications were observed. Within this study’s limitations, immediate guided palatonasal implants demonstrated satisfactory short-term implant and prosthesis survival, minimal marginal bone changes, improved peri-implant soft tissues, and high patient satisfaction. Longer randomized controlled trials are warranted.