Evaluation of the intaglio surface shape of implant-supported complete-arch maxillary prostheses and its association with biological complications: An analytical cross-sectional study.

Statement Of Problem: Whether the shape of the intaglio surface of fixed implant-supported maxillary prostheses is associated with the occurrence of biological is unclear.

Purpose: The purpose of this cross-sectional study was to evaluate the shape (convex or concave) of the intaglio surface of complete-arch implant-supported maxillary fixed prostheses and to assess the association with biofilm accumulation, hyperemia, bone loss, and patient satisfaction.

Material And Methods: Study participants consisted of 56 individuals with fixed complete implant-supported maxillary prosthesis attending follow-up appointments. The 56 prostheses supported by 388 implants had been in place for an average of 5.5 years (range 1-14 years). The intaglio surface was divided into areas corresponding to the cantilever regions and between implants (n=442) and was assessed for shape (concave or convex) and biofilm index (0 to 3). Tissue hyperemia (redness) was assessed as absent or present. Bone loss (mm) was measured from digital periapical radiographs by 2 calibrated evaluators (kappa=94.9%). Study participant satisfaction was investigated by using a visual analog scale. Association assessments (α=.05) between the shape of each area and all these parameters were performed with the Friedman, linear regression, and logistic regression tests.

Results: Of the analyzed areas, 58 (13.1%) were concave, and 384 (86.9%) were convex. Biofilm was absent on 3.5% of the concave and 5.5% of the convex areas. Biofilm was detectable with a probe on 12% of the concave and 22.4% of the convex areas and clinically visible in 58.6% of the concave and 57.8% of the convex areas. Abundant biofilm was seen in 25.9% of the concave and 14.3% of the convex areas and was associated with hyperemia (P=.003). A statistically significant association was found between the shape and biofilm accumulation (P=.009). Hyperemia was present in 199 (45%) areas. The association analysis between the shape of the area and the presence of hyperemia was not significant (P>.05). The mean bone loss was 0.71 mm (0.91 mm). Implants placed near concave areas underwent greater bone loss (P=.001). Study participants reported a high level of satisfaction with the esthetics, mastication, speech, and smile provided by the prosthesis, with satisfaction scores ranging between 8.46 and 8.77. However, in relation to ease of cleaning, only 19.6% were fully satisfied.

Conclusions: The shape of the intaglio surface of prostheses influenced the occurrence of biofilm accumulation and bone loss, and concave areas showed greater biofilm accumulation and bone resorption. High rates of satisfaction with treatment were identified.