Remodeling Pattern of Mandible after “All-on-4” Immediate Fixed Rehabilitation: A Radiographic Study

doi:10.13701/j.cnki.kqyxyj.2020.10.016

Abstract

Abstract: Objective: To investigate the pattern of mandible remodeling after “All-on-4” immediate fixed rehabilitation and its influential factors. Methods: 30 patients rehabilitated with “All-on-4” implant-supported fixed restorations were studied. All patients were followed-up for more than 1 year. Panoramic radiographs (OPT) were taken after the completion of prosthetic restoration and during the follow-up period. The samples were investigated by 2-dimensional radiological retrospective analysis. 7 sites on the mandible were marked (M: mid-line site; ML/MR: the sites between two implants on the same side; L1/R1: molar sites; L2/R2: retromolar sites) based on the anatomical landmarks and the locations of implants on the OPTs. The vertical bone heights were measured and the average annual bone resorption rates were calculated on these 7 sites. Correlation analysis was conducted for age, gender, initial mandibular height, and chewing force, respectively. Results: Bone resorption was observed on sites ML, M, and MR [ML:(-0.02±0.33) mm/year;M:(-0.15±0.27) mm/year;MR:(-0.02±0.22) mm/year]. Bone augment was discovered at L1/R1 [L1: (0.25±0.57) mm/year, R1: (0.21±0.61) mm/year]. While slight alveolar height increments were recorded at L2/R2 [L2: (0.07±0.580 mm/year, R2: (0.01±0.52) mm/year]. Furthermore, chewing force was positively correlated with the height changes at site L1/R1 (P<0.05). Conclusion: “All-on-4” immediate fixed rehabilitation may change the mandible remodeling pattern. Placing implants between the mental foramen contributes to the lower resorption rate in the area between mental foramen and fixed rehabilitation contributes to the increments of vertical bone height at the molar sites of the mandible.

Key words: alveolar bone loss, dental implants, implant-supported dental prosthesis, all-on-4

JIA Shengnan, DI Ping, LIN Ye. Remodeling Pattern of Mandible after “All-on-4” Immediate Fixed Rehabilitation: A Radiographic Study[J]. Journal of Oral Science Research, 2020, 36(10): 957-961.

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