ALVEOLAR DIMENSIONAL VARIATIONS IN ALVEOLAR PRESERVATION AND POST-EXTRACTION IMMEDIATE MAXILLARY IMPLANTS—A 3-D MULTILEVEL MULTIVARIATE PROSPECTIVE STUDY
by Tiago Borges (Portugal), Bruno Leitão, Miguel Pereira, Ágata Carvalho

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Objectives: The aim of the study was to evaluate the bone dimensional alterations that occur following tooth extraction and immediate or secondary implant installation in the maxillary arch, and the factors that may influence it, through assessment of early healing events and dimensional changes of the buccal and lingual walls of fresh extraction sockets following immediate implant installation compared to alveolar preservation and secondary implant placement. Methods: Thirty-five patients (mean age 49.58 ± 11.09 years) treated with 37 single-tooth implants in the maxillary area (from 15 to 25) were included in this study. Before surgery, patients were randomly assigned to two groups to ensure balanced distribution. In group A, fresh extraction sockets were filled with Bio-OssTMdeproteinised bovine bone material (DBBM) and sealed with a resorbable collagen membrane (Mucograf SealTM). Implants were inserted 16 weeks after alveolar preservation. In group B, implants were placed over immediate extraction sites with no compromise of the buccal bone plate and left to heal for a period of 16 weeks, following a two-stage protocol. The implant surface–alveolar buccal wall gap was filled with the same DBBM material. Cone-beam CT was performed after extraction and implant placement (baseline), and at 4 weeks (T1), 16 weeks (T2) and 1 year (T3) after surgery, to assess buccal plate height (BH), palatal plate height (PH), buccal–palatal coronal distance (BPD) and buccal plate thickness (BPT). Mean values of each groups were compared using a t-test and ANOVA for comparison of multiple variables. A Pearson correlation analysis assessed the influence of the alveolar anatomy and extension of bone resorption in at different time sets. Statistical significance was set at 0.05. Results: Thirty-one patients (mean age 43.6 ± 11.4 years; range 30–66) treated with thirteen alveolar bone preservation procedures (Group A) and twenty single-tooth immediate implants (Group B) were examined. Of the initial thirty-five patients, one was excluded due to implant failure and three failed did not finish the recall program (all were in group B). At baseline, group A had BPT at the incisive/canine sites of 0.48 ± 0, 36mm, and 0.93 ± 0.36mm at premolar locations. Group B had BPT of 0.91 ± 0.47mm and 1.22 ± 0.98mm for the incisive/canine and premolar sites, respectively. A normal distribution was found for both groups regarding BPT. At T2, there was a reduction in bone dimensions. No significant changes were found in BH between baseline and T2 in either group. Significant differences were found in BPD from baseline to T1 and from baseline to T2, with a statistically significant reduction in buccal–palatal volume in both groups. A positive correlation was found between BPT and the reduction in buccal–palatal volume, described by the BPD measurements, in both groups. Conclusion: Both treatments failed to prevent bone resorption. Immediate implant installation in fresh sockets with DBBM particles was no better than alveolar bone preservation in terms of bone preservation of fresh extraction sockets, but both treatments reduced bone loss after extraction compared to non-grafted sites (described in the literature), and may help clinicians to make decisions about immediate implant placement into sockets. Future studies might compare this type of placement with other treatments in the anterior maxillary region, and consider different timings of placement and related surgical procedures.
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Content Type:
Poster
Publication date:
10/01/2016
Publisher: