Rotational path removable partial mandibular resection prostheses: A case series of patients with mandibular symphyseal defects.

Rotational path removable partial mandibular resection prostheses (MRPs) offer advantages in the management of patients with acquired symphyseal defects of the mandible, including enhanced esthetics achieved through a reduced number of clasps, the provision of rigid retainers less prone to distortion compared with flexible alternatives, and the ability to engage prominent proximal undercuts in patients lacking buccal undercuts. Additionally, removable partial MRPs represent a suitable treatment option in scenarios where the cost of implant-retained prostheses is prohibitive or in patients where implant therapy is contraindicated, such as those with a history of head and neck radiation. While the use of rotational path removable prostheses has been well documented in conventional prosthodontics, its application in maxillofacial prosthetics remains less explored. This case series describes 3 patients, all of whom underwent mandibular resections involving the mandibular symphysis and subsequently received prosthetic rehabilitation incorporating rotational path removable partial MRPs.

Disparity in the Influence of Implant Provisional Materials on Human Gingival Fibroblasts with Different Phases of Cell Settlement: An In Vitro Study.

The development of healthy peri-implant soft tissues is critical to achieving the esthetic and biological success of implant restorations throughout all stages of healing and tissue maturation, starting with provisionalization. The purpose of this study was to investigate the effects of eight different implant provisional materials on human gingival fibroblasts at various stages of cell settlement by examining initial cell attachment, growth, and function. Eight different specimens-bis-acrylic 1 and 2, flowable and bulk-fill composites, self-curing acrylic 1 and 2, milled acrylic, and titanium (Ti) alloy as a control-were fabricated in rectangular plates (n = 3). The condition of human gingival fibroblasts was divided into two groups: those in direct contact with test materials (contact experiment) and those in close proximity to test materials (proximity experiment). The proximity experiment was further divided into three phases: pre-settlement, early settlement, and late settlement. A cell culture insert containing each test plate was placed into a well where the cells were pre-cultured. The number of attached cells, cell proliferation, resistance to detachment, and collagen production were evaluated. In the contact experiment, bis-acrylics and composites showed detrimental effects on cells. The number of cells attached to milled acrylic and self-curing acrylic was relatively high, being approximately 70% and 20-30%, respectively, of that on Ti alloy. There was a significant difference between self-curing acrylic 1 and 2, even with the same curing modality. The cell retention ability also varied considerably among the materials. Although the detrimental effects were mitigated in the proximity experiment compared to the contact experiment, adverse effects on cell growth and collagen production remained significant during all phases of cell settlement for bis-acrylics and flowable composite. Specifically, the early settlement phase was not sufficient to significantly mitigate the material cytotoxicity. The flowable composite was consistently more cytotoxic than the bulk-fill composite. The harmful effects of the provisional materials on gingival fibroblasts vary considerably depending on the curing modality and compositions. Pre-settlement of cells mitigated the harmful effects, implying the susceptibility to material toxicity varies depending on the progress of wound healing and tissue condition. However, cell pre-settlement was not sufficient to fully restore the fibroblastic function to the normal level. Particularly, the adverse effects of bis-acrylics and flowable composite remained significant. Milled and self-curing acrylic exhibited excellent and acceptable biocompatibility, respectively, compared to other materials.

Use of zirconia onlays in a maxillary removable implant-supported denture: A clinical report.

A common complication with the use of acrylic resin denture teeth is wear of the occlusal surfaces. Modifying the occlusal surfaces with gold onlays has been suggested to combat this phenomenon. This clinical report describes the use of zirconia as an alternative material on a patient with increased tendencies for occlusal wear. The advantages of using zirconia include wear resistance, decreased cost, and straightforward fabrication.

Double sleeve guided placement of quadruple zygomatic implants for rehabilitation of a patient with ectodermal dysplasia: A clinical report.

The surgical and prosthodontic treatment for a 22-year-old man with ectodermal dysplasia is described and illustrated. He had never managed to wear complete dentures, and implant-retained or implant-supported prostheses were indicated. However, the placement of conventional maxillary endosseous implants was contraindicated. A novel surgical template with double sleeves was used to guide osteotomies for 4 zygomatic implants used with an unloaded, one-stage approach. After confirming osseointegration, prosthetic rehabilitation began with an interim implant-supported fixed prosthesis to evaluate esthetics, phonetics, and hygiene maintenance. Clinical challenges included lip biting and speech articulation.

Modified vestibuloplasty of the zygomaticoalveolar crest to gain intradefect support for an obturator prosthesis.

This clinical report details a novel surgical modification at the time of maxillectomy to improve obturator function. A vestibuloplasty and split thickness skin graft of the zygomaticoalveolar crest created a denture-bearing surface that, when engaged, provided support and stability for the obturator prosthesis. This report outlines the surgical and prosthodontic procedures and the results achieved.

Prosthetic reconstruction of a patient with an irradiated total rhinectomy with navigated surgical placement of a single zygomatic implant: A clinical report.

This clinical report details the rehabilitation of a patient who underwent a total rhinectomy, subsequent adjuvant radiation therapy, and eventual prosthetic rehabilitation but then developed an empirically diagnosed medical adhesive intolerance. With the aid of digital planning and real time navigation, 2 zygomatic implants were placed by using a flapless surgical approach followed by early delivery of an interim prosthesis. In spite of the failure of 1 craniofacial implant, definitive restoration was accomplished by using a titanium bar, double magnetic attachments, and a new silicone prosthesis.

Digital workflow for predictable immediate loading in the mandible by using a shape memory dental implant abutment system: A clinical report.

Digital surgical planning for immediately loaded dental implants can be a predictable and accurate procedure, with the interim prosthesis also designed digitally. If the planning and execution are meticulous, chairside adjustments can be minimized because the outcome should be closely matched to the proposed digital plan. A novel dental implant abutment system made from a shape memory metal could be an answer to the cement versus screw controversy as it uses neither. This new system can provide patients with better esthetics and is biologically favorable.

Digital custom implant impression technique for capturing the acquired emergence profile.

A digital method for capturing the acquired emergence profile from contoured implant interim restorations is described. Three separate digital scans were made by using an intraoral scanner and aligned by using a design software program capable of merging and alignment. The Boolean Difference function was then performed by using a free software program to obtain the emergence profile. This technique may be less time-consuming than analog methods and may be more accurate than existing digital methods.

Human Gingival Fibroblast Growth and Function in Response to Laser-Induced Meso- and Microscale Hybrid Topography on Dental Implant Healing Abutments.

PURPOSE: To examine the behavior and function of human gingival fibroblasts growing on healing abutments with or without laser-textured topography. MATERIALS AND METHODS: Human primary gingival connective tissue fibroblasts were cultured on healing abutments with machined or laser-textured (Laser-Lok, BioHorizons) surfaces. Cellular and molecular responses were evaluated by a variety of tests, including cell density assay (WST-1), fluorescence microscopy, real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and detachment tests. RESULTS: The machined surface showed monodirectional traces and scratches from milling, whereas the laser-textured surface showed a distinct morphology consisting of monodirectional mesoscale channels (15-µm pitch) and woven oblique microridges formed within the channels. There were no differences in initial fibroblast attachment, subsequent fibroblast proliferation, or collagen production between the machined and laser-textured surfaces. Fibroblasts growing on a laser-textured surface were found to spread in one direction along the mesochannels, while cells growing on machined surfaces tended to spread randomly. Fibroblasts on laser-textured surfaces were 1.8 times more resistant to detachment than those on machined surfaces. An adhesive glycoprotein (fibronectin) and transmembrane adhesion linker gene (integrin ß-1) were upregulated on laser-textured surfaces. CONCLUSIONS: The increased fibroblast retention, uniform growth, and increased transcription of cell adhesion proteins compellingly explain the enhanced tissue-level response to laser-created and hybrid-textured titanium surfaces. These results provide a cellular and molecular rationale for the tissue reaction to this unique surface; in addition, they support its extended use, from implants and healing abutments to diverse prosthetic components where enhanced soft tissue responses would be desirable.

Conditional Mitigation of Dental-Composite Material-Induced Cytotoxicity by Increasing the Cure Time.

Light-cured composite resins are widely used in dental restorations to fill cavities and fabricate temporary crowns. After curing, the residual monomer is a known to be cytotoxic, but increasing the curing time should improve biocompatibility. However, a biologically optimized cure time has not been determined through systematic experimentation. The objective of this study was to examine the behavior and function of human gingival fibroblasts cultured with flowable and bulk-fill composites cured for different periods of time, while considering the physical location of the cells with regard to the materials. Biological effects were separately evaluated for cells in direct contact with, and in close proximity to, the two composite materials. Curing time varied from the recommended 20 s to 40, 60, and 80 s. Pre-cured, milled-acrylic resin was used as a control. No cell survived and attached to or around the flowable composite, regardless of curing time. Some cells survived and attached close to (but not on) the bulk-fill composite, with survival increasing with a longer curing time, albeit to <20% of the numbers growing on milled acrylic even after 80 s of curing. A few cells (<5% of milled acrylic) survived and attached around the flowable composite after removal of the surface layer, but attachment was not cure-time dependent. Removing the surface layer increased cell survival and attachment around the bulk-fill composite after a 20-s cure, but survival was reduced after an 80-s cure. Dental-composite materials are lethal to contacting fibroblasts, regardless of curing time. However, longer curing times mitigated material cytotoxicity exclusively for bulk-fill composites when the cells were not in direct contact. Removing the surface layer slightly improved biocompatibility for cells in proximity to the materials, but not in proportion to cure time. In conclusion, mitigating the cytotoxicity of composite materials by increasing cure time is conditional on the physical location of cells, the type of material, and the finish of the surface layer. This study provides valuable information for clinical decision making and novel insights into the polymerization behavior of composite materials.

Cell Type-Specific Effects of Implant Provisional Restoration Materials on the Growth and Function of Human Fibroblasts and Osteoblasts.

Implant provisional restorations should ideally be nontoxic to the contacting and adjacent tissues, create anatomical and biophysiological stability, and establish a soft tissue seal through interactions between prosthesis, soft tissue, and alveolar bone. However, there is a lack of robust, systematic, and fundamental data to inform clinical decision making. Here we systematically explored the biocompatibility of fibroblasts and osteoblasts in direct contact with, or close proximity to, provisional restoration materials. Human gingival fibroblasts and osteoblasts were cultured on the "contact" effect and around the "proximity" effect with various provisional materials: bis-acrylic, composite, self-curing acrylic, and milled acrylic, with titanium alloy as a bioinert control. The number of fibroblasts and osteoblasts surviving and attaching to and around the materials varied considerably depending on the material, with milled acrylic the most biocompatible and similar to titanium alloy, followed by self-curing acrylic and little to no attachment on or around bis-acrylic and composite materials. Milled and self-curing acrylics similarly favored subsequent cellular proliferation and physiological functions such as collagen production in fibroblasts and alkaline phosphatase activity in osteoblasts. Neither fibroblasts nor osteoblasts showed a functional phenotype when cultured with bis-acrylic or composite. By calculating a biocompatibility index for each material, we established that fibroblasts were more resistant to the cytotoxicity induced by most materials in direct contact, however, the osteoblasts were more resistant when the materials were in close proximity. In conclusion, there was a wide variation in the cytotoxicity of implant provisional restoration materials ranging from lethal and tolerant to near inert, and this cytotoxicity may be received differently between the different cell types and depending on their physical interrelationships.

Shape-Memory Retained Complete Arch Guided Implant Treatment Using Nitinol (Smileloc) Abutments.

A case report of a complete arch interim prosthesis executed using digital work flows and with guided implant surgery is presented. The novel shape-memory retained system used to retain the complete dental prosthesis is easily indexed onto the remaining dentition, thereby being both efficient and cost-effective in the short and long term.