ABSTRACT

Purpose of the study: The aim of the present study was to investigate the marginal bone height changes around maxillary and mandibular implants supporting all on four fixed detachable prosthesis after one year follow up

Materials and methods: six completely edentulous patients (4 males and 2 females) received new conventional maxillary and mandibular dentures and were asked to wear them for 3 months to enhance adaptation. Four implants were inserted in the maxillary (between the nasal sinuses) and mandibular (between the mental foramina) arch of each patient according to the All On four protocol. Implants were immediately loaded with provisional dentures after connection of multiunit abutments, and after 3 months of osseointegration temporary dentures were replaced by fixed ceramo-metal prosthesis. Vertical marginal bone loss (VBL) was evaluated at the time of fixed hybrid prosthesis insertion, 6 and 12 months later using standardized peri-apical radiographs.

Results: Maxillary anterior implants recorded significant higher VBL (P ≤ 0.005) than mandibular implants after 6 months and 12 months of prosthesis insertion. Also, the maxillary anterior implants showed significant VBL (P ≤ 0.005) than the posterior implants. For the posterior implants, no significant difference in VBL was observed between the maxillary and mandibular implants. For the mandibular implants, no significant difference in VBL between the anterior and posterior implants was observed.

Conclusion: Within the limitation of this short-term study, taking the small patient cohort into account, it could be concluded that maxillary anterior implants supporting all on four fixed hybrid prosthesis are at increased risk for marginal bone loss compared to maxillary posterior implants or mandibular implants.