Extreme atrophy of the maxilla poses still challenging for the clinicians. Some of the techniques used could be complex, risky, expensive, time consuming and should be performed, preferably, only by skilled surgeons. Most the commonly used techniques have been reported to have very high success percentages; however, sometimes complications may occur. In this regard, Premaxillary Device (PD) is a technique that has been devised to render more simple the reconstruction of extremely atrophic maxilla, trying to avoid more complicated and risky surgical procedures. Finite Element Analysis (FEA) allows evaluation of several differen aspects of dental implant biomechanics. Our results showed that the use of PD allows an optimal distribution of the stresses on the basal bone, avoiding tension peaks that could determine bone resorption or, even, implant failure. ANSYS has been used to perform this type of localized finite element analysis; with this type of analysis, it was possible to analyze the peri-crestal area of the plant more precisely and the PD through a more accurate reconstruction of the mesh element, which allowed us to mathematically solve the FEA solution. A most favorable biomechanical behavior has been found for the materials such as titanium alloys and reduce stress levels for bone, implants, screws, and abutments. Moreover, the stress values did not exceed bone strength limits for basal bone and titanium alloy. In conclusion, from a biomechanical point of view, PD could be considered a viable alternative for rehabilitation of severe atrophic maxilla.

The aim of this study was to evaluate implants survival rate, marginal bone loss, surgical and prosthetic complications of implants placed through sinus floor elevation and tilted implants en-gaged in basal bone in order to bypass maxillary sinus. 60 patients were enrolled for this study. According with residual bone height of posterior maxilla the sample was divided in three groups of 20 patients: Group A (lateral sinus floor elevation), Group B (transrectal sinus floor elevation) and Group C (tilted implants employed to bypass sinus floor). Follow-up visits were performed one week after surgery, at 3, 6 months and then once a year for next 4 years. The outcomes were implants survival rate, marginal bone loss and surgical and prosthetic complications. Although the Group A, B and C have demonstrated an implants survival rate of 83.3%, 86,7% and 98,3% respectively, the statistically analysis showed that there was no statistically significant difference between groups. Statistically significant differences between the groups were also not found con-cerning marginal bone loss, as recorded by intra-oral X-ray measurements during follow-up. About complications it wasn’t possible to perform a statistical analysis. To as to reduce potential surgical risks implants placement in basal bone should be preferred.

The purpose of this study was to investigate the functional load capacity of the periodontal ligament (PDL) in a full arch maxilla and mandible model using numerical simulation. The goal of was to determine the functional load pattern in multi- and single rooted teeth with full and reduced periodontal support. CBCT data were used to create 3D-models of a maxilla and mandible. The DICOM dataset was used to create a CAD-model. For a precise description of the surfaces of each structure (enamel, dentin, cementum, pulp, PDL, gingiva, bone), each tooth was segmented separately, and the biomechanical characteristics were considered. A Finite-Element-Analysis (FEA) software computed the biomechanical behavior of stepwise increased force of 700N in cranial and 350N in ventral direction of the muscle approach of the Masseter muscle. The periodontal attachment (cementum-PDL-bone contact) was subsequently reduced in 1mm increments and the simulation repeated. Quantitative (pressure, tension, and deformation) and qualitative (color-coded images) data were recorded and descriptively analyzed. The teeth with the highest load capacities were the upper and lower molars (0.4-0.6MPa), followed by the premolars (0.4-0.5MPa) and canines (0.3-0.4MPa) when vertically loaded. Qualitative data showed that the area with the highest stress in the PDL were for single rooted teeth the cervical and apical area and for molars additionally the furcation roof. In both, single- and multi rooted teeth the gradual reduction of the bone levels caused an increase of the load on the remaining PDL. Cervical and apical areas as well as the furcation roof are the zones with the highest functional stress. The more bone loss, the higher the mechanical load on the residual periodontal supporting structures.

The study aimed to evaluate implant success and bone height variations after transcrestal sinus floor elevation (tSFE) using the osseodensification technique (OD) combined with beta-tricalcium phosphate (β-TCP), as bone graft material and simultaneous implant placement. Thirteen patients requiring the placement of one implant in the upper posterior maxilla, with a residual bone height of

(1) Background: In orthognathic surgery, segmental Le Fort I osteotomies are a valuable method to correct maxillary deformities or transversal discrepancies. However, these procedures are technically challenging, and osteosynthesis can be prone to error. (2) Methods: In this retrospective, monocentric cohort study, patients were enrolled who underwent a virtually planned segmental maxillary osteotomy during their combined treatment. Positioning and osteosynthesis were achieved by either a 3D-printed splint and conventional mini plates or Patient-Specific Implants (PSI). The preoperative CT data, virtual planning data, and postoperative CBCT data were segmented. The deviation of all segments from the desired virtually planned position was measured using the analysis function of the IPS Case Designer. (3) Results: 28 Patients in the PSI Group and 22 in the conventional groups could be included. The PSI group showed significantly lower deviation from the planned position anteroposteriorly (-0.63±1.62mm vs. -1.3±2.54mm) and craniocaudally (-1.39±1.59mm vs. -2.7±3.1mm). For rotational deviations, the Pitch (0.64±2.59° vs. 2.91±4.08°) as well as the inward rotation of the lateral segments was positively influenced by PSI. (4). Conclusions: The presented data show that patient-specific osteosynthesis significantly reduces deviations from the preoperative plan in virtually planned cases. Especially transversal expansions and vertical positioning can be addressed better.