The effect of frontal trauma on the edentulous mandible with four different interforaminal implant-prosthodontic anchoring configurations. A 3D finite element analysis.

PURPOSE: The present three-dimensional (3D) finite element analysis (FEA) was aimed to assess the biomechanical effects and fracture risks of four different interforaminal implant-prosthodontic anchoring configurations exposed to frontal trauma. MATERIAL AND METHODS: A symphyseal frontal trauma of 1 MPa was applied to four dental implant models with different configurations (two unsplinted interforaminal implants [2IF-U], two splinted interforaminal implants [2IF-S], four unsplinted interforaminal implants[ 4IF-U], four splinted interforaminal implants [4IF-S]. By using a 3D-FEA analysis the effective cortical bone stress values were evaluated in four defined regions of interest (ROI) (ROI 1: symphyseal area; ROI 2: preforaminal area; ROI 3: mental foraminal area; and ROI 4: condylar neck) followed by a subsequent intermodel comparison. RESULTS: In all models the frontal traumatic force application revealed the highest stress values in the condylar neck region. In both models with a four-implant configuration (4IF-U, 4IF-S), the stress values in the median mandibular body (ROI 1) and in the condylar neck region (ROI 4) were significantly reduced (P <0.01) compared with the two-implant models (2IF-U, 2IF-S). However, in ROI 1, the model with four splinted implants (4IF-S) showed significantly (P < 0.01) reduced stress values compared to the unsplinted model (4IF-U). In addition, all models showed increased stress patterns in the area adjacent to the posterior implants, which is represented by increased stress values for both 2IF-U and 2IF-S in the preforaminal area (ROI 3) and for the four implant-based models (4IF-U, 4IF-S) in the mental foraminal area. CONCLUSION: The configuration of four splinted interforaminal implants showed the most beneficial distribution of stress pattern representing reduced stress distribution and associated reduced fracture risk in anterior symphysis, condylar neck and preforaminal region.

Clinical features of peri-implant medication-related osteonecrosis of the jaw: Is there an association to peri-implantitis?

The purpose of this study was to examine the behavior of dental implants in patients diagnosed with MRONJ and to analyze the characteristics of peri-implant MRONJ. It was hypothesized that peri-implant parameters are not associated with peri-implant MRONJ. A retrospective study design was selected to address the research purpose. Patients with confirmed MRONJ and the simultaneous presence of dental implants who presented between 2010 and 2016 served as the study cohort. Predefined inclusion and exclusion criteria were applied. Demographic, clinical and radiological data were collected and analyzed statistically with respect to the variable scale (significance level p ≤ 0.05). The study sample was composed of 34 patients (female: 16; male: 18; average age: 70.6 years) with a total of 117 dental implants the majority of whom had received antiresorptive drug therapy within oncologic treatment protocols. Peri-implant MRONJ occurred in 15 patients (44%). Signs of peri-implantitis (present around 46/117 implants; 39%) appeared to be associated with the occurrence of peri-implant MRONJ. Patients receiving antiresorptive drugs in high doses seem to be at risk of developing MRONJ in the vicinity of dental implants. Peri-implantitis may be associated with the etiology of peri-implant MRONJ.