RESUMO
Implant-prosthetic rehabilitation of missing teeth in the anterior maxilla is often challenging due to ongoing bone resorption and remodeling events and may require regeneration procedures involving the nasopalatine canal (NPC). We describe a surgical approach with a block graft in relation to the NPC and evaluate clinical performance, sensory perception, and aesthetic result of the implant-prosthetic treatment over a two- to nine-year (mean: 3.5 years) follow-up. Ten implants (six in the right central incisor and four in the left central incisor) were, respectively, placed in 10 consecutive patients with bone defects affecting the NPC and unfavorable widening of the incisive foramen. Treatment stages included: (1) Diagnosis: evaluation of clinical-aesthetic parameters using Cone Beam Computed Tomography; (2) Surgery: block graft placement by palatine and incisal with simultaneous guided bone regeneration, and late (6-10 months) implant placement; (3) Prosthetics: placement of a screw-retained crown (torque of 32 N/cm). At treatment initiation, all the NPCs evaluated in our study were free of pathologies. Treatment evaluation included bone crest thickness, neurosensory status, patients' treatment perception, and pink and white aesthetic scores (PES/WES). Pre-surgery, anterior ridge thickness at the level of the incisive foramen was (mean ± SD) 3.5 ± 2 mm, 5.4 ± 1.5 mm, and 6.1 ± 1.9 mm at heights of 4, 8, and 14 mm apical to the marginal bone crest, respectively. Post-treatment values were, respectively, 10.1 ± 2.0 mm, 10.5 ± 1.0 mm, and 13.4 ± 3.0 mm. The perception of treatment with the aesthetic pink and white indices (PES/WES) was an average of 7.5 and 7 points, respectively, out of a total of 10 each index, with a recovery of 100% of the neurosensory perception of the area. We propose that bone augmentation using block and particulate graft material can compensate for anatomical variations in the NPC, optimize implant's three-dimensional positioning and improve facial contour, providing tissue and implant stability and good aesthetic outcomes.
RESUMO
OBJECTIVES: This study aimed to evaluate the retention on two or four implants of eight resilient and nonresilient retentive anchors used in overdentures. METHOD AND MATERIALS: Eight groups of retentive anchors were used: Dyna and Shiner (magnets); Dalla Bona and O-Ring (balls); Ceka Revax and Zaag attachments (studs); the cast bar (Dolder type) system with plastic clips; and the milled bars system. These specimens with their respective overdentures were prepared on two similar acrylic resin models with four implants (3.75 x 13 mm). Ten tensile strength tests (Instron) were performed on each group at a speed of 3 mm per minute. The statistical analysis (one-way analysis of variance, Tukey's HSD test) was considered significant. RESULTS: The pull force values ranged between 0.400 and 3.800 daN (International System of Units). There was a significant difference in retention in favor of the milled bars in comparison with the Ceka Revax, Hader bars, Zaag attachments, O-Ring, and Dyna groups, and a marginally significant difference compared with the Dalla Bona group. There was a highly significant difference with the Shiner magnets. CONCLUSION: The milled bar system was the most retentive anchor, with the Dalla Bona, Ceka Revax, Hader Bar, Zaag attachment, and O-Ring groups being the second most retentive. The least retentive groups were the Shiner and Dyna magnets. Proper abutment placement in the mandible and the correct selection of the retentive anchor will improve overdenture retention.