Prosthodontic criteria for maxillary immediate occlusal loading, surgical classifications of atrophic maxillae, and presentation of a new implant/anatomic classification system for immediate maxillary rehabilitation. Journal of prosthodontics : official journal of the American College of Prosthodontists PURPOSE:Immediate full-arch occlusal loading for patients with atrophic edentulous maxillae satisfies critical needs for this specific type of edentulous patient after placement of implants with high levels of primary implant stability. The needs include improved aesthetics, limited immediate improved function, and elimination of removable prostheses. Classification systems exist for edentulous maxillae but they do not include specifics regarding posterior implant placement. In conjunction with anterior implants, posterior implants improve Anterior/Posterior (A/P) spreads, decrease cantilevered segments (CLs), and likely will improve implant and prosthetic success rates. The purposes of this article include presenting a new classification system that outlines the different types of implants now available which will likely achieve the requisite primary stability for immediate fixed rehabilitation. This proposed classification system identifies a relationship between different implant options currently available and the remaining quantity of bone in the first and second maxillary molar zones. MATERIALS AND METHODS:The available literature regarding current classification systems was reviewed. The benefits and limitations of each system were described. The parameters associated with Immediate Occlusal Loading (IOL) for full arch maxillary prostheses include: posterior cantilever lengths of full arch fixed prostheses; existing A/P spread considerations for full arch prostheses; and introduction of a new classification system for atrophic posterior maxillary edentulous ridges were identified. RESULTS:Currently, there are no available classification systems that outline specific implant options for posterior maxillae which will likely achieve the minimum primary stability needed for immediate rehabilitation. A new classification system was proposed where the rationale was to show clinicians that when a certain amount of bone remains in the posterior maxilla, there are specific implants designed to maximize primary stability. High implant primary stability is required for rehabilitation with immediate fixed implant-supported provisional prostheses. The proposed classification system assists clinicians in understanding what implant geometry is available and can be expected to achieve the requisite primary stability for immediate occlusal loading based on the available bone in the posterior maxillary molar zone. CONCLUSIONS:This article reviewed current classification systems for edentulous maxillary patients, as well as clinical parameters required for full arch, immediate occlusal loading.  It also presented a new classification system to assist clinicians in selecting appropriate implants and surgical techniques for immediate fixed rehabilitation of patients with atrophic maxillae. 10.1111/jopr.13898

Single missing molar with wide mesiodistal length restored using a single or double implant-supported crown: A self-controlled case report and 3D finite element analysis. Journal of prosthodontic research PURPOSE:Based on a self-controlled case, this study evaluated the finite element analysis (FEA) results of a single missing molar with wide mesiodistal length (MDL) restored by a single or double implant-supported crown. METHODS:A case of a missing bilateral mandibular first molar with wide MDL was restored using a single or double implant-supported crown. The implant survival and peri-implant bone were compared. FEA was conducted in coordination with the case using eight models with different MDLs (12, 13, 14, and 15 mm). Von Mises stress was calculated in the FEA to evaluate the biomechanical responses of the implants under increasing vertical and lateral loading, including the stress values of the implant, abutment, screw, crown, and cortical bone. RESULTS:The restorations on the left and right sides supported by double implants have been used for 6 and 12 years, respectively, and so far have shown excellent osseointegration radiographically.The von Mises stress calculated in the FEA showed that when the MDL was >14 mm, both the bone and prosthetic components bore more stress in the single implant-supported strategy. The strength was 188.62-201.37 MPa and 201.85-215.9 MPa when the MDL was 14 mm and 15 mm, respectively, which significantly exceeded the allowable yield stress (180 MPa). CONCLUSIONS:Compared with the single implant-supported crown, the double implant-supported crown reduced peri-implant bone stress and produced a more appropriate stress transfer model at the implant-bone interface when the MDL of the single missing molar was ≥14 mm. 10.2186/jpr.JPR_D_23_00278

Marginal bone loss in dental implants: A literature review of risk factors and treatment strategies for prevention. Journal of prosthodontic research PURPOSE:Marginal bone loss (MBL) occurs in the periapical cervical bone after dental implant placement and abutment connection. MBL may not result in peri-implantitis; however, it is always accompanied by MBL. Recent studies have demonstrated that early MBL is a predictor of peri-implantitis. In this narrative review, we aimed to provide an evidence base for recommended treatment strategies for clinicians to prevent MBL. STUDY SELECTION:We reviewed the recent literature and performed a narrative synthesis of the evidence, focusing on available systematic reviews and meta-analyses of implant marginal bone resorption. RESULTS:The available evidence indicates that certain biological, material, and technical factors can influence MBL and consequently dictate the risk of developing peri-implant disease in later years. The order of the impact of the strength of each factor is unknown. Current recommendations to prevent MBL include controlling patients' smoking and hemoglobin A1c levels to sufficiently low levels before surgery and throughout their lifetime. Regarding the material, a platform-switching, conical-connecting implant system, and an abutment with a height of at least 2 mm should be selected. Placement should be performed using techniques that ensure sufficient soft tissue (keratinized gingival width > 2 mm, supracrestal tissue height > 3 mm), and non-undersized preparations in the cortical bone should be made with connected concave abutments during primary or secondary surgery. Patients should receive supportive peri-implant therapy during maintenance. CONCLUSIONS:MBL development is multifactorial and can be reduced by considering the biological, material, and technical factors. 10.2186/jpr.JPR_D_23_00223