ABSTRACT
Objectives: To radiographically evaluate the effect of the degree of palatal coverage on crestal bone height around maxillary hybrid -implants.
Methods: Fourteen edentulous patients with conventional maxillary and mandibular complete dentures were included in this study. Four hybrid implants (one piece 3 mm in diameter, 12 mm in length) were installed in maxillary arch of each patient in areas of lateral incisors and first premolars to retain maxillary implant overdenture then the upper denture was modified by reduction of the palatal coverage area for half of the patients and was followed radiographically for one year.
Results: In this study, at the end of follow up period, there was statistically significant difference between the two groups regarding the average bone loss around the dental implants as shown by student t-test. The least bone loss was reported around the implants in group I. After six months, the mean differences of bone height loss were (0.745 ± 0.098) and (0.77 ± 0.051) mm while from six to twelve month, the mean differences of bone height loss were (0.50 ± 0.041) and (0.57 ± 0.036) mm in group I and group II respectively.

Conclusion: Bone height loss around implants was increased by reduction of the palatal coverage.