Dental prostheses

Tobacco consumption is a significant global health issue, responsible for over eight million deaths annually. Various forms of tobacco, including cigarettes, hookah, smokeless tobacco, and electronic cigarettes, have been linked to oral cancer, particularly squamous cell carcinoma. Individuals wearing dental prostheses, whether removable or fixed, are at an increased risk due to chronic mucosal irritation, which may accelerate carcinogenic processes when combined with tobacco exposure. Accordingly, this systematic review explored the relationship between tobacco consumption and oral cancer in patients with dental prostheses, with a focus on different tobacco types and their respective carcinogenic mechanisms. A comprehensive literature search was conducted in PubMed, Scopus, and Web of Science, covering publications from January 2000 to March 2023. Studies examining adult prosthesis users, their tobacco consumption patterns, and oral cancer outcomes were included in this review. The final analysis encompassed twenty-two studies of case-control, cohort, and cross-sectional designs. The findings consistently demonstrated that tobacco use amplifies oral cancer risk in prosthesis wearers due to the synergistic effects of chronic mechanical irritation, inflammation, oxidative stress, and microbial dysbiosis. Notably, different tobacco products exhibited varying carcinogenic mechanisms. While cigarette and hookah smoke led to polycyclic aromatic hydrocarbon exposure, smokeless tobacco caused prolonged mucosal nitrosamine contact, and e-cigarette aerosols induced oxidative DNA damage. This review highlights the critical need for routine oral examinations, prosthesis maintenance, and integrated tobacco cessation interventions to mitigate oral cancer risks in this vulnerable population. Future research should focus on identifying high-risk subgroups, evaluating innovative prosthetic materials with lower inflammatory potential, and elucidating the molecular pathways.

An ideal complete denture must achieve a delicate balance between rigidity and resilience. The polished surface should possess adequate strength to resist masticatory loads, while the tissue-bearing surface should provide cushioning and flexibility to ensure uniform stress distribution. Conventional acrylic dentures, being entirely rigid, frequently transmit occlusal loads unevenly, resulting in mucosal trauma, discomfort, and progressive alveolar bone resorption. This problem is accentuated in patients with flabby or atrophic ridges, where mobile fibrous tissue distorts under pressure, compromising denture stability and retention. The liquid-supported denture concept offers a biologically compatible solution that integrates a rigid acrylic base with a flexible, fluid-filled interface capable of dynamic adaptation to functional stresses. By incorporating a thin polyethylene sheet and a viscous liquid such as glycerin, the system enables equalized stress transmission, reduced mucosal distortion, and enhanced comfort. This report describes the clinical and laboratory procedures involved in fabricating a liquid-supported complete denture for a 72-year-old male patient presenting with a flabby anterior maxillary ridge. The steps-from impression making and spacer adaptation to final sealing and patient evaluation-are explained in detail. The outcome demonstrated improved retention, stability, and patient satisfaction. The liquid-supported denture thus represents a conservative yet effective alternative for prosthodontic rehabilitation of compromised ridges where surgical or implant options are unsuitable.

Rehabilitation of missing maxillary anterior teeth with malpositioned implants presents significant esthetic and functional challenges. This case describes a 29-year-old male who lost both maxillary central incisors due to trauma, with implant placement in region 11 positioned buccally outside the ideal prosthetic envelope. Clinical and radiographic evaluation revealed adequate bone volume, allowing prosthetic correction without additional surgery. Management involved a custom cobalt-chromium abutment for implant 11, a prefabricated angled titanium abutment for implant 21, and digital design of a two-unit porcelain-fused-to-metal bridge using Exocad software. The framework was fabricated via Direct Metal Laser Sintering (DMLS) and veneered with natural and pink porcelain to optimize emergence profile, interdental spacing, and gingival esthetics. The final prosthesis achieved excellent functional stability and esthetic integration, successfully correcting implant malposition. This case demonstrates that combining digital workflows, customized abutments, and additive manufacturing can effectively address complex anterior implant restorations, emphasizing the importance of precise diagnosis, interdisciplinary planning, and tailored prosthetic strategies for predictable long-term success.

INTRODUTION A superficial region of movable soft tissue influencing the maxillary or mandibular alveolar ridges was referred to as a "flabby" or "fibrous" ridge. It was a common discovery, especially in long-term denture wearers, and can arise when hyperplastic soft tissue replaces the alveolar bone. Trauma from denture bases is said to be the cause of these ridges. [1] It was more frequently discovered in the anterior area in the edentulous patient. Kelly originally identified "combination syndrome" in 1972 based on observations made during a 3-year followup period with six patients. Every patient had a removable partial denture that extended distally and a complete maxillary denture that was opposed by mandibular teeth. [2] He noted the growth of the tuberosities, the resorption of alveolar bone in the front maxilla, and the resorption of bone beneath the bases of the mandibular dentures. Histologically, hyperplastic mucosal tissue, loosely distributed fibrous connective tissue, and robust collagenous connective tissue make up flabby ridges. There is a significant quantity of visible metaplastic cartilage and/or bone in the soft tissue. [3]

The high failure rate of the Yttria Partially Stabilized Zirconia (YPSZ)-porcelain interface in dental prostheses is influenced by the micro-scale mechanical property variation in this region. To improve the understanding of this behavior, micro-scale fracture toughness profiling by nanoindentation micropillar splitting is reported for the first time. Sixty 5 μm diameter micropillars were machined within the first 100 μm of the interface. Berkovich nanoindentation provided estimates of the bulk fracture toughness of YPSZ and porcelain that matched the literature values closely. However, the large included tip angle prevented precise alignment of indenter with the pillar center. Cube corner indentation was performed on the remainder of the pillars and calibration between nanoindentation using different tip shapes was used to determine the associated conversion factors. YPSZ micropillars failed by gradual crack propagation and bulk values persisted to within 15 μm from the interface, beyond which scatter increased and a 10% increase in fracture toughness was observed that may be associated with grain size variation at this location. Micropillars straddling the interface displayed preferential fracture within porcelain parallel to the interface at a location where nano-voiding has previously been observed and reported. Pure porcelain micropillars exhibited highly brittle failure and a large reduction of fracture toughness (by up to ~90%) within the first 50 μm of the interface. These new insights constitute a major advance in understanding the structure-property relationship of this important bi-material interface at the micro-scale, and will improve micromechanical modelling needed to optimize current manufacturing routes and reduce failure.

Immediate dentures are removable prostheses fabricated before extraction and delivered immediately postextraction to maintain esthetics, function, and psychological well-being during healing. [1,2] Conventional workflows involve multiple steps-initial impressions, bite registration, facebow transfer, model surgery, and wax try-in-each susceptible to errors related to material properties, clinical handling, or laboratory inaccuracies. [3-7] With advancements in digital dentistry, including intraoral scanning, computer-aided design/computer-aided manufacture, and three-dimensional (3D) printing, many of these limitations are being addressed. [1] Digital technologies enable virtual tooth extractions, simulated soft tissue changes, and preoperative prosthetic visualization, thereby improving predictability and reducing chairside time. [8-10] However, one challenge in immediate denture fabrication is accurately recording vestibular border extensions without compromising Integration of digital technology in prosthodontics enables precise and predictable outcomes. A hybrid digital-conventional workflow combines the accuracy of digital protocols with the reliability of traditional techniques. A 46-year-old male with generalized aggressive periodontitis required full-mouth extraction and immediate dentures. Intraoral scans were captured at the existing vertical dimension and used to design custom trays in EXOCAD. The trays, three-dimensional-printed with windows for natural teeth, facilitated border molding and final impressions for soft tissue capture. These impressions were digitized, superimposed on intraoral scans, and used to create a virtual model, perform virtual extractions, and fabricate definitive dentures. The digital approach improved patient comfort, accelerated planning, and enhanced accuracy, while conventional steps ensured an optimal peripheral seal in scanner-inaccessible areas. The technique delivered a functionally stable and esthetically satisfactory outcome.

Cleft lip and cleft palate is one of the common developmental disorders of head and neck region with increasing incidences every year. Feeding problems for infants and children are one of the common complaints of patients with cleft lip and palate. Patients with cleft lip and palate can syndromic or nonsyndromic. Common difficulties arising due to this condition is inability to form complete seal in the oral cavity leading to nasal regurgitation and choking. This article presents the Prosthodontic management of an infant with a cleft palate through fabricating a feeding plate.

A completely edentulous patient reported to the Department of Prosthodontics for replacement of worn out dentures. Extensive resorption of lower ridge and fibrous anterior maxillary ridge was found. As the surgical intervention was refused by the patient, a gel-supported denture was planned. The prosthodontic science has seen a vast progress in techniques and material advances in complete denture planning. Yet there has been no solution to the age-old problem of soreness under a denture and continued ridge resorption. A complete denture must be adequately rigid to bear masticatory forces and, at the same time, exhibit flexibility and softness on the tissue surface for proper and even distribution of the masticatory forces. However, a conventional denture is rigid on all surfaces, leading to uneven distribution of load which often presents as soreness. Various methods and materials have been used to give a cushioning effect to the tissues when dentures are actually in use. A gel-supported denture is adequately rigid on the polished surface and equally resilient on the tissue surface. This technique allows continued adaptation of the denture to the mucosa in the resting and functional states.

Introduction: The objective of this study in vitro was to evaluate the retentive forces of PEEK and Co-Cr alloy clasps by the insertion and removal test simulating 10 years use. Material and Methods: 16 PEEK clasps and 16 Co-Cr clasps were fabricated for 32 third molars with similar dimensions. Each clasp assembly was subjected to an insertion /removal test on its abutment molar with a Test Universal Machine (Instron® 4465, Instron Co. Ltd, Norwwod, MA) to analyze with Newton the retention force. To analyze the retention over the course of insertion/removal test, retention was measured every 1500 cycles. With a total of 15000 cycles, which represents the insertion / removal of the clasp for 10 years, estimating that the patient would do four full cycles a day. Results: Co-Cr clasps showed higher retention (mean 13,63 Nw) than PEEK clasps (mean 8,04 Nw). All clasps exhibited an increase in retentive force during the first period of cycling followed by continuous decrease. Were obtained significant differences between retention forces of each material groups (p<0.001). Conclusions: We can use PEEK clasps for removable prostheses. Retention forces of PEEK clasps were clinically acceptable, but inferior retention forces of Co-Cr clasps. They are needed in vivo studies to contrast the results.

This clinical trial aimed to assess the clinical performance of 3D-printed resin composite fixed dental prostheses (FDPs) for posterior restorations. Methods: From October 10, 2020, to August 5, 2022, a total of 49 patients (33 females and 16 males), aged 19 to 60, were treated with 68 three-unit 3D-printed resin composite posterior FDPs (ELS Even Stronger, Saremco, Switzerland). Two weeks after placement, the FDPs were evaluated by two independent observers using modified FDI criteria. Parameters assessed included anatomical form, secondary caries, marginal adaptation, surface roughness, color match, material fracture, surface staining, margin staining, anatomical form, retention, gingival health, and patient satisfaction. Failures were classified as either mechanical or biological. Results: The mean observation period was 22.36 months. At the final recall, of the 64 FDPs, 24 remained in clinical service without any complications, indicating limited long-term success. Almost all restorations maintained normal anatomical contours throughout the follow-up period. During the initial six-month period, 9 instances of fractures were identified, followed by 14 after 1 year, 11 after two-year a further 2 cases after a threeyear period of clinical service. Of the 40 failed FDPs, 36 exhibited mechanical failures, while 6 showed biological failures (2 cases exhibited both and were counted in both categories). Thirty-four FDPs showed cohesive fractures. Two FDPs were re-bonded, four abutment teeth required endodontic treatment, and two presented periodontal issues. Additionally, 2 FDPs exhibited a loss of surface luster, 4 exhibited color mismatches, and 4 exhibited surface staining (all scored 4). Kaplan-Meier analysis revealed a 40.7 % survival rate for mechanical failures and a 36.2 % survival rate when biological complications were included. Conclusions: The results of a three-year follow-up study indicated that 3D-printed resin composite FDPs present failures mainly in the connector region, suggesting the need for further design improvements. Clinical Significance: Three-dimensionally printed resin composite FDPs offer certain advantages but current restorations could be considered as long-term provisional due to the incidence of mainly mechanical failures up to 3 years.

This clinical trial aimed to assess the clinical performance of 3D-printed resin composite fixed dental prostheses (FDPs) for posterior restorations. Methods: From October 10, 2020, to August 5, 2022, a total of 49 patients (33 females and 16 males), aged 19 to 60, were treated with 68 three-unit 3D-printed resin composite posterior FDPs (ELS Even Stronger, Saremco, Switzerland). Two weeks after placement, the FDPs were evaluated by two independent observers using modified FDI criteria. Parameters assessed included anatomical form, secondary caries, marginal adaptation, surface roughness, color match, material fracture, surface staining, margin staining, anatomical form, retention, gingival health, and patient satisfaction. Failures were classified as either mechanical or biological. Results: The mean observation period was 22.36 months. At the final recall, of the 64 FDPs, 24 remained in clinical service without any complications, indicating limited long-term success. Almost all restorations maintained normal anatomical contours throughout the follow-up period. During the initial six-month period, 9 instances of fractures were identified, followed by 14 after 1 year, 11 after two-year a further 2 cases after a threeyear period of clinical service. Of the 40 failed FDPs, 36 exhibited mechanical failures, while 6 showed biological failures (2 cases exhibited both and were counted in both categories). Thirty-four FDPs showed cohesive fractures. Two FDPs were re-bonded, four abutment teeth required endodontic treatment, and two presented periodontal issues. Additionally, 2 FDPs exhibited a loss of surface luster, 4 exhibited color mismatches, and 4 exhibited surface staining (all scored 4). Kaplan-Meier analysis revealed a 40.7 % survival rate for mechanical failures and a 36.2 % survival rate when biological complications were included. Conclusions: The results of a three-year follow-up study indicated that 3D-printed resin composite FDPs present failures mainly in the connector region, suggesting the need for further design improvements. Clinical Significance: Three-dimensionally printed resin composite FDPs offer certain advantages but current restorations could be considered as long-term provisional due to the incidence of mainly mechanical failures up to 3 years.

This paper reports a wireless passive resonator architecture that is used as a fiducial electronic marker (e-marker) intended for internal marking purposes in magnetic resonance imaging (MRI). As a proofof-concept demonstration, a class of double-layer, sub-cm helical resonators were microfabricated and tuned to the operating frequency of 123 MHz for a three T MRI system. Effects of various geometrical parameters on the resonance frequency of the e-marker were studied, and the resulting specific absorption rate (SAR) increase was analyzed using a full-wave microwave solver. The B + 1 field distribution was calculated, and experimental results were compared. As an exemplary application to locate subdural electrodes, these markers were paired with subdural electrodes. It was shown that such sub-cm self-resonant e-markers with biocompatible constituents can be designed and used for implant marking, with sub-mm positioning accuracy, in MRI. In this application, a free-space quality factor (Q-factor) of approximately 50 was achieved for the proposed resonator architecture. However, this structure caused an SAR increase in certain cases, which limits its usage for in vivo imaging practices. The findings indicate that these implantable resonators hold great promise for wireless fiducial e-marking in MRI as an alternative to multimodal imaging.

This paper reports a wireless passive resonator architecture that is used as a fiducial electronic marker (e-marker) intended for internal marking purposes in magnetic resonance imaging (MRI). As a proofof-concept demonstration, a class of double-layer, sub-cm helical resonators were microfabricated and tuned to the operating frequency of 123 MHz for a three T MRI system. Effects of various geometrical parameters on the resonance frequency of the e-marker were studied, and the resulting specific absorption rate (SAR) increase was analyzed using a full-wave microwave solver. The B + 1 field distribution was calculated, and experimental results were compared. As an exemplary application to locate subdural electrodes, these markers were paired with subdural electrodes. It was shown that such sub-cm self-resonant e-markers with biocompatible constituents can be designed and used for implant marking, with sub-mm positioning accuracy, in MRI. In this application, a free-space quality factor (Q-factor) of approximately 50 was achieved for the proposed resonator architecture. However, this structure caused an SAR increase in certain cases, which limits its usage for in vivo imaging practices. The findings indicate that these implantable resonators hold great promise for wireless fiducial e-marking in MRI as an alternative to multimodal imaging.

The aim of this study was to evaluate and compare the outcomes of immediately loaded all-ceramic crown restorations supported by implants placed in both mature bone and immediate extraction sockets. Materials and Methods: Forty-three tapered, external hex implants were placed immediately after extraction or in healed bone in a convenience sample of 38 patients from two clinics, with 23 implants immediately placed after tooth extraction and 20 placed in mature bone. Thirty implants were located in the maxilla and 13 in the mandible. Each surgical implant placement was followed by the fabrication of a screw-retained all-ceramic crown (zirconia-toughened alumina cylinder and layered with porcelain) that was then put into immediate function. Each patient was recalled annually for clinical and radiographic assessments. Results: All implants were loaded immediately and all functioned successfully following a mean follow-up of 26 months. Significantly more bone loss was recorded around delayed implants compared with immediately placed ones. Smoking, platform switching, and jaw location did not influence peri-implant bone loss. Porcelain chipping was noted in the case of two crowns. The short-term outcome of prefabricated ceramic cylinders used to support a single screw-retained crown was regarded as successful. Immediate implant placement did not appear to increase the risk for implant failure and was accompanied by reduced peri-implant bone loss.

The aim of this study was to evaluate and compare the outcomes of immediately loaded all-ceramic crown restorations supported by implants placed in both mature bone and immediate extraction sockets. Materials and Methods: Forty-three tapered, external hex implants were placed immediately after extraction or in healed bone in a convenience sample of 38 patients from two clinics, with 23 implants immediately placed after tooth extraction and 20 placed in mature bone. Thirty implants were located in the maxilla and 13 in the mandible. Each surgical implant placement was followed by the fabrication of a screw-retained all-ceramic crown (zirconia-toughened alumina cylinder and layered with porcelain) that was then put into immediate function. Each patient was recalled annually for clinical and radiographic assessments. Results: All implants were loaded immediately and all functioned successfully following a mean follow-up of 26 months. Significantly more bone loss was recorded around delayed implants compared with immediately placed ones. Smoking, platform switching, and jaw location did not influence peri-implant bone loss. Porcelain chipping was noted in the case of two crowns. Conclusion: The short-term outcome of prefabricated ceramic cylinders used to support a single screw-retained crown was regarded as successful. Immediate implant placement did not appear to increase the risk for implant failure and was accompanied by reduced peri-implant bone loss.

Since the 17th century, archaeological evidence for dental prosthetics and restorative dentistry has constantly increased. Artificial dentures first appeared in central Europe among the upper classes; however, they were mainly used for aesthetic reasons. It was not until the 19th century that the raw material of hard rubber made it possible to manufacture a functional dental prosthesis in which porcelain teeth were inserted. With the development of synthetic plastics, dentures became a mass product. Based on burials from Germany, Austria and Switzerland, the paper traces the most important steps in the development of dental prosthetics and presents, in addition to the materials used, other technical aspects concerning the anchoring of the teeth and the attachment of the prosthesis in the mouth. The interplay of these parameters can contribute to a dating of a burial in the sense of a terminus post quem. At the same time, based on our sample we discuss the availability and affordability of such measures for different social classes. Using our database we explore the potential of the typo-chronological and social classification of dental appliances between the 17th and the mid-20th century.

This case report describes an alternative method to rehabilitate completely edentulous atrophic ridges by the use of liquid supported denture. Liquid supported dentures eliminate the disadvantages of denture designs and allows continued adaptation of denture over the denture bearing area based on the application of vacuum heat pressed polyethylene sheets filled with fluid.

Volume 48 Issue 3 (September 2024) https://powertechjournal.com for comparison with the main algorithm proposed in this article is the use of a threshold limit instead of the FBP active contour model for initial separation; That means, first, by using a threshold limit, the metal regions in the sinogram image are separated with very low accuracy. Then by applying the mentioned Hough transformation to the separated parts, these areas are identified with high approximation. The result of applying this algorithm to the real data (sinogram image of the patient with tooth filling material and hip prosResearch) and the data related to the mentioned mollage scan sinogram along with the results of the main algorithm are obtained. Compared to the original algorithm, the results of this algorithm are the same for the data related to mollage and for the data related to the patient with dental filling materials and hip prosResearch of lower quality. In fact, because the dental filling materials are small and large, as well as the number of hip prosResearch parts for the relevant data in this research is high, and on the other hand, the data is related to the spiral CT scan.

Introduction: the removable dental prostheses is a rehabilitation treatment that returns the functions to the stomatognathic system; for its successful action it is necessary responsibility and commitment between the professional and the patient on hygiene and mode of use. Objective: to determine the hygienic condition of the removable acrylic prostheses in patients attended in the dental clinics at San Gregorio de Portoviejo University in the period March - August 2019. Method: A cross-sectional descriptive study was conducted using a validated questionnaire and observation worksheet. All participants in the research provided handwritten signature informed consent form before answering the questionnaire and being examined. Descriptive statistics, frequency and percentage were applied. Results: a total of 100 patients were evaluated, with higher prevalence in females (74%), and 50 years of age or more (54%). The results show that 53% of the patients use prostheses made for five or m...

Resorption of alveolar ridges is a dynamic process. It is a continuous process, with varying rates in individual at different times. Due to residual ridge resorption, complete denture prosthesis seldom remains in close adaptation to underlying soft tissues, causing tissue irritation and alteration in underlying mucosa. Denture base have to be flexible to adapt underlying mucosa, and rigid to withstand masticatory forces. Also the incorrect tooth placement and arbitrary shaping of the polished surfaces also questions the success of prosthesis, which can be managed by using neutral zone concept. This case report presents the use neutral zone for atrophic mandibular ridge and fluid retained denture for flabby tissue in anterior maxillary arch.

Denture adhesives (DA) improve the retention and stability of ill-fitting dentures, especially for older adults. These materials should be biocompatible, i.e., they cannot cause undesired biological responses and be non-cytotoxic to oral tissues. However, in vitro testing of DA biocompatibility employing primary cell culture may possibly be affected by other factors, such as the donor age. To compare the cytotoxicity of three different denture adhesives when assessed in primary gingival fibroblasts from a young donor or from an older donor, as well as the release of the basic fibroblast growth factor (bFGF), and the inflammatory response marker interleukin-6 (IL-6). Gingival fibroblasts isolated from a 30- and a 62-year-old donor were assayed for proliferation (1-7 days) and sensitivity to latex (positive control). Fibroblasts were indirectly exposed to Corega Ultra (cream), Corega powder and Fixodent Original for a 24 h period and assayed by XTT and Crystal Violet tests. The releas...

summary  Nylon denture base material could be a useful alternative to poly (methyl methacrylate) (PMMA) in special circumstances such as patient allergy to the monomer. The aim of this study was to evaluate the flexural properties of a nylon denture base material (Lucitone FRS), a conventional compression‐moulded heat‐polymerized (Meliodent), a compression‐moulded microwave‐polymerized (Acron MC) and an injection‐moulded microwave‐polymerized (Lucitone 199) PMMA polymers. The effect of aldehyde‐free, oxygen releasing disinfectant solution (Perform®) on these properties was also investigated. The flexural modulus and the flexural strength were assessed with a three‐point bending test. Specimens were stored in water at a temperature of 37 °C for 30 days. For each material, half of the prepared specimens were randomly selected and immersed in the disinfectant 24 h prior to testing. Results were compared statistically at a confidence level of 95%. The result showed that in both the cont...

right. To fulfill these requirements a retainer should provide means of primary retention, vertical force transmission, and occlusal force transmission (Blaterfein 1969). All clasp assemblies must be designed so that they satisfy the following six requirements: 1) Retention: Provides resistance to vertical dislodgement, 2) Stability: Provides resistance to horizontal forces, 3) Support: Provides resistance to vertical seating, 4) Reciprocation: Provides resistance to horizontal forces exerted on a tooth by an active retentive clasp, 5) Encirclement: Engages the tooth greater than 180° to prevent horizontal tooth movement from within the confines of a clasp assembly, 6) Passivity: Puts no active force on a tooth when a clasp is in place (Phoenix et al. 2003, Jones and García 2009). There are many factors affecting the retention of the extracoronal direct retainers (clasps). Applegate (1965), Osborne and Lammie (1974), Korl (1976), and Henderson and Steffel (1981) listed four factors to be considered in determining the amount of clasp retention to be used, these factors are the angle of infrabulge convergence, the distance below the height of contour, the accuracy of adaptation to the contacting surface, and the flexibility of the clasp arms. The retention of RPD clasp depends upon the following features: (1) number and position of the saddles and the guiding planes, (2) mobility of the teeth, (3) mechanical properties of the alloy, (4) dimensions of the clasps; shape, length, and taper, and (5) design of clasps (Bates 1980). The dislodging force was dependent on the fit of the framework, the depth of the undercut, the number of the clasps, and its point of application (Ahmed et al. 1992). However, La Vere (1993) listed five factors that determine clasp retention, and summarized them in the following three categories (1) the fit of the clasp to the abutment, (2) the flexibility of the retentive arm, and (3) the condition of the abutment. Others investigated the effect of clasp material on the retention force of the clasp. Bates (1965) studied the mechanical properties of cobalt chromium alloys (Co-Cr) and their relation to RPDs. The author reported that the minimum undercut to be tested for the Co-Cr alloys should be 0.25 mm and the clasps should be at least 15 mm long. Where undercuts greater than 0.25 mm are available on the teeth, a gold clasp is to be preferred, since it has adequate flexibility and a safety margin not available with Co-Cr alloys. The significant differences exist in the fatigue resistance of RPD clasps made from different commercial cast metals, which may cause loss of retention of the RPD

Rapid advancements in computer-aided design and computer-aided manufacturing (CAD-CAM) have opened new pathways in the fabrication of removable partial denture (RPD) frameworks through additive and subtractive processes. 1 To produce a digital file that can be milled or 3D printed, sophisticated 3D dental modeling software programs have been used. Several commercial CAD software systems, including 3Shape Dental System and Exocad, have recently become available for 3D designing of RPD frameworks. 2 Once digitally designed, different pathways exist for the fabrication of the RPD framework. The typical digital workflow includes obtaining a digital model of the oral hard and soft tissues. This can be accomplished directly from an intraoral digital scan or from a laboratory digital scan of a stone cast. Second, the path of insertion is defined, and undercuts are color coded based on the

Rapid advancements in computer-aided design and computer-aided manufacturing (CAD-CAM) have opened new pathways in the fabrication of removable partial denture (RPD) frameworks through additive and subtractive processes. 1 To produce a digital file that can be milled or 3D printed, sophisticated 3D dental modeling software programs have been used. Several commercial CAD software systems, including 3Shape Dental System and Exocad, have recently become available for 3D designing of RPD frameworks. 2 Once digitally designed, different pathways exist for the fabrication of the RPD framework. The typical digital workflow includes obtaining a digital model of the oral hard and soft tissues. This can be accomplished directly from an intraoral digital scan or from a laboratory digital scan of a stone cast. Second, the path of insertion is defined, and undercuts are color coded based on the

The world is a growing place with great technological advancement in all areas of life. For some decades now, various disciplines and industries have been engaged in using Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) across different nations. CAD/CAM utilizes computers to integrate design and manufacturing processes for quality product attainment. This review article examined the present impacts of CAD/CAM on some sectors such as architecture, manufacturing, engineering and design, electronics, automobile, shipbuilding, aerospace, and medicine. Highlights on some applications and future impacts of CAD/CAM have also been discussed. The numerous impacts of CAD/CAM are discussed in the study. It was concluded that CAD/CAM had become integral parts of our world to ease production against traditional methods. The study recommended more research focus on biomaterials for 3-D bioprinting for tissue engineering applications.

In the realm of biomaterials engineering, Functionally Graded Materials (FGMs) have emerged as a novel class of composites, characterized by spatial variations in composition that yield a gradient in properties tailor-made for specific applications. This investigation delineates the development of a multi-layered FGM composed of titanium, nickel, and hydroxyapatite (NiTi/HA), designed to address the challenges associated with bone implant integration. Porous NiTi, renowned for its mechanical compatibility with bone tissue, is coupled with hydroxyapatite, a material celebrated for its osteoconductive properties, to enhance bioactivity and promote bone ingrowth. The fabrication of this NiTi/HA FGM was realized through a powder metallurgy approach, culminating in the production of specimens with either three or five stratified layers that progressively transition from NiTi-rich at one extremity to HA-rich at the other. The compaction of these powders was executed under a pressure of 450 MPa, followed by a sintering process at 1000°C sustained for a duration of three hours-parameters meticulously chosen to optimize material integrity without compromising the functional gradient. Mechanical characterization was systematically conducted, revealing that the microhardness of the FGMs ranged from 269.6 to 458.11 kg/mm 2 and 365.5 to 436.5 kg/mm 2 for the threelayered and five-layered specimens, respectively. The density and porosity of these materials were also quantified, with the three-layered FGM (FGM1) exhibiting an apparent density of 2.665 g/cm 3 and a porosity of 33.5%, while the five-layered FGM (FGM2) displayed an increased density of 3.754 g/cm 3 and a reduced porosity of 24.6%. X-ray diffraction analysis verified the phase composition of the graded specimens, confirming the presence of the anticipated monoclinic NiTi, cubic NiTi, and hexagonal Ni3Ti phases, integral to the material's function. The synergistic combination of the robust mechanical properties of the NiTi alloy with the superior bioactivity of hydroxyapatite underscores the potential of this FGM NiTi/HA for hard tissue implant applications, offering a promising avenue for the advancement of orthopedic treatments.

The details of this case have been omitted in order to maintain anonymity. forensic odontology unit at the University of Pretoria for examination and comparative analysis. An elderly male was reported missing from his home by his family. Initially, an inquiry and missing person&#39;s docket was opened. On investigation, several suspicious ifndings, along with other emerging evidence led to the case being changed into one of kidnapping. Unbeknown to the investigating officers, around the same time a body had been found buried in a shallow grave about 200 kilometers from the missing person&#39;s home (First burial). The body had been taken to the state mortuary were a post-mortem was performed. At that stage there was no connection made to the missing person&#39;s case and after the body remained unclaimed, the corpse was given a pauper&#39;s funeral (Second burial).

Objectives: Cleft lip and palate (CLP) is one of the most common congenital deformities with worldwide prevalence. It causes a range of issues for infants that mainly involve difficulty in feeding due to abnormal oronasal communication. For this purpose, feeding plates are provided to infants to act as an artificial palate to aid in feeding. The most crucial procedure in fabrication of a feeding plate is creation of the impression using the traditional finger technique or impression trays. This preliminary research aims to compare the effectiveness of novel impression trays with that of the traditional finger technique for recording impressions of infants with CLP. Materials and Methods: This randomized controlled trial was conducted among 30 infants who were divided into two groups based on the method of obtaining impressions: Group I, finger technique; Group II, specialized acrylic tray (cleftray). Results: Use of cleftray required less impression time, a reduced amount of material, no incidence of cyanosis/choking in infants, and lower anxiety among doctors compared to the traditional method. Additionally, there was no distortion of cleft impressions, recorded maxillary tuberosity, or other fine details. Therefore, the novel impression tray (cleftray) exhibited superior outcomes in all the parameters compared to the finger technique. Conclusion: Within the limitations of this study, we conclude that impression trays are superior to the traditional finger, spoon, or ice cream stick methods of creating impressions of CLP. However, it is necessary to conduct more clinical trials on a larger population based on other parameters to compare the effectiveness of the two techniques to draw definitive conclusions.

BACKGROUND: The introduction and evolution of CAD/CAM technology into complete dentures fabrication brought high expectations in improving disadvantages associated with conventional methods.AIM: The purpose of this review was to analyse the existing literature on computer-engineered complete dentures and to determine their advantages over the conventional dentures.MATERIAL AND METHODS: An electronic search of the English literature from January 1994 to March 2018 was performed in PubMed/MEDLINE, using the following keywords: CAD/CAM complete dentures, computer-engineered complete dentures, complete digital dentures, complete milled dentures, and rapid prototyping dentures.RESULTS: A total of 179 English language titles were obtained from the database, and 14 were relevant to fulfil the purpose of this review. A review of 7 articles is summarized in 2 tables for presenting a comparison between CAD/CAM and conventional dentures in clinical and laboratory studies.CONCLUSION: Following ...

Conventional complete denture lacks retention and stability in patients with fibrous hyperplasic tissue. The ideal properties of a denture are adequate rigidity of polished surface to bear masticatory forces and at the same time, flexibility and softness for better stress distribution. In conventional denture, there is uneven distribution of load due to rigidity of tissue surface, especially in the case of flabby, atrophic ridge. A Liquid supported denture allows uniform stress distribution due to its flexible tissue surface and improve the patient&#39;s acceptance.

Objectives Despite the complexity of the edentulous anatomy, little evidence exists as to what impression techniques and materials should be employed for an optimal result. The aim of this in silico study was to evaluate the trueness of peripheral and inner seals of different edentulous jaw impressions. Materials and methods Twelve maxillary edentulous participants (male = 8, female = 4; age 68.5 ± 11.7 years) participated in this study. Four different impression materials and techniques, irreversible hydrocolloid (Alginate; Blueprint X-Crème, Dentsply Sirona, PA, USA), polyvinyl siloxane impression (PVS; Aquasil Ultra+ Medium, Dentsply Sirona, PA, USA), and subsequently modified with ZnOE (PVSM) and an optical impression (Optical; 3Shape A/S, Copenhagen, Denmark), were tested against a control impression: low-fusing impression compound border molding (Kerr Corp., CA, USA) followed by a ZnOE impression (ZnOE; SS White impression paste, S.S. White Group, Gloucester, England). All impressions were scanned and analyzed using a custom-built 3D comparison software analyzing the vertical and horizontal trueness. Results The vertical discrepancy (peripheral seal) of the impression surface was significantly more true for PVSM than Alginate (p = 0.001), PVS (p = 0.019), and Optical groups (p < 0.001). Where the horizontal discrepancy (inner seal) was compared, the impression surface was more true for PVSM than Alginate (p < 0.001) and Optical (p < 0.001). PVS group was also significantly more true than Optical (p = 0.015). Conclusion Impression techniques and materials may significantly influence the peripheral and inner seal of an edentulous jaw impression. Clinical relevance When using a polyvinylsiloxane impression material for master edentulous impressions, a selective inner seal reline with a conventional zinc oxide eugenol impression paste can improve the inner seal.

The success of complete denture is enhanced by achieving the objectives of impression making, that is preservation of underlying tissue, retention, stability, support and esthetics. Flabby tissue is a common clinical finding affecting the alveolar ridges of both mandibular or maxillary arches. The use of conventional impression techniques for recording flabby tissues can lead to unstable and unsatisfactory denture. But some modification in the impression techniques can record the flabby tissues in an undistorted form and thus help to fabricate a stable denture. The problem with conventional denture is rigidity of material which comes in contact with tissue surface, leading to uneven distribution of load. A liquid supported denture allows uniform stress distribution due to its flexible tissue surface and provides improved patient's acceptance.

Nano-zirconia, also known as nanocrystalline zirconia or zirconia nanoparticles, is a versatile material with numerous applications in various fields, including catalysis, sensors, energy storage, and biomedical engineering. This review manuscript explores the synthesis methods of nano-zirconia, focusing on the sol-gel method, precipitation method, hydrothermal method, flame spray pyrolysis, and template-assisted synthesis. Each method is discussed in detail, highlighting its advantages and disadvantages. The selection of a synthesis approach depends on factors such as desired properties, scalability, cost, and equipment availability. Furthermore, the study examines specific dental applications where nano-zirconia materials find utility. In dental implantology, nano-zirconia implants have shown promising results in terms of osseointegration, with comparable or superior performance to titanium implants. Surface modifications, such as bioactive coatings, have been explored to enhance ...

Hard skills and soft skills arises from a learning recognized by an academic training sanctioned by diplomas. This learning is doubled by an interpersonal skills which leans on an emotional intelligence acquired during the education and during the teaching. If soft skills soft and hard skills are necessary and complementary in the practice of a profession or a function within an organization or a company, the part of the weight of each component of the two types of there skills exchange in time ... This article shows in which sense this evolution is made and why as well the recruiters as the recruits have to feel to reach there. A rebalancing of soft and hard skills has to be made by a coaching from the upstream in training to give their fruits downstream in the professional world.

Bio-composites with vegetal reinforcement have experienced great industrial development in various sectors of activity such as: automotive, electronics, medical, or construction. Compared with synthetic fibers, plant fibers have numerous environmental, technical, processing, economic and health advantages. With the objective of application in the dental field, we present in this paper the study of bacterial adhesion on a biomaterial composite with polypropylene reinforced vegetable fibers extracted from the Alfa plant (stepa tenassicma). For this study, two strains of bacteria from the oral bacterial flora were chosen, Lactobacillus acidophilus and Streptococcus mutans, and analyzed by spectrophotometric method. The results analysis shows clearly the formation of biofilm by bacterial adhesion is remarkable in the presence of the composite not reinforced by vegetable fibers in comparison with the biocomposite reinforced by Alfa fibers, and more remarkably formed by the strain Streptococcus mutans than with the strain Lactobacillus acidophilus.

Background: Incisor loss constitutes a strong aesthetic and psychologic traumatism for the patient and it remains a challenging situation for the dental practitioner because of the necessity to rapidly replace the lacking tooth. Various therapeutic procedures have been proposed to replace the incisor concerned, for example by using a removable partial denture. However, the manufacturing of such a denture with classical procedures is often subject to processing errors and inaccuracies. The computer-aided design and computer-aided manufacturing (CAD-CAM) technology could represent a good alternative, but it is currently difficult because of the lack of dental softwares able to design easily immediate removable partial dentures. Case presentation: A 30-year-patient complained about pain caused by a horizontally and vertically mobile maxillary right central incisor. After all options were presented, extraction of the traumatized incisor was decided due to its very poor prognosis, and the patient selected the realization of a removable denture for economic reasons. The present paper proposes an innovative procedure for immediate removable denture, based on the use of an intraoral scanner, CAD with two different softwares used sequentially, and CAM with a 5-axis machine. Conclusions: We show in this report that associating an intraoral scanner and CAD-CAM technology can be extended to immediate dentures manufacturing, which could be a valuable procedure for dental practitioners and laboratories, and also for patients.

Background: Incisor loss constitutes a strong aesthetic and psychologic traumatism for the patient and it remains a challenging situation for the dental practitioner because of the necessity to rapidly replace the lacking tooth. Various therapeutic procedures have been proposed to replace the incisor concerned, for example by using a removable partial denture. However, the manufacturing of such a denture with classical procedures is often subject to processing errors and inaccuracies. The computer-aided design and computer-aided manufacturing (CAD-CAM) technology could represent a good alternative, but it is currently difficult because of the lack of dental softwares able to design easily immediate removable partial dentures. Case presentation: A 30-year-patient complained about pain caused by a horizontally and vertically mobile maxillary right central incisor. After all options were presented, extraction of the traumatized incisor was decided due to its very poor prognosis, and the patient selected the realization of a removable denture for economic reasons. The present paper proposes an innovative procedure for immediate removable denture, based on the use of an intraoral scanner, CAD with two different softwares used sequentially, and CAM with a 5-axis machine. Conclusions: We show in this report that associating an intraoral scanner and CAD-CAM technology can be extended to immediate dentures manufacturing, which could be a valuable procedure for dental practitioners and laboratories, and also for patients.

Background: The purpose of this paper is to review the available literature on three-dimensionally printed complete dentures in terms of novel biomaterials, fabrication techniques and workflow, clinical performance and patient satisfaction. Methods: The methodology included applying a search strategy, defining inclusion and exclusion criteria, selecting studies and forming tables to summarize the results. Searches of PubMed, Scopus, and Embase databases were performed independently by two reviewers to gather literature published between 2010 and 2020. Results: A total of 126 titles were obtained from the electronic database, and the application of exclusion criteria resulted in the identification of 21 articles pertaining to printed technology for complete dentures. Current innovations and developments in digital dentistry have successfully led to the fabrication of removable dental prostheses using CAD/CAM technologies. Milled dentures have been studied more than 3D printed ones in the currently available literature. The limited number of clinical studies, mainly case reports, suggest current indications of 3D printing in denture fabrication process to be custom tray, record bases, trial, interim or immediate dentures but not definitive prostheses fabrication. Limitations include poor esthetics and retention, inability to balance occlusion and low printer resolution. Conclusions: Initial studies on digital dentures have shown promising short-term clinical performance, positive patient-related results and reasonable cost-effectiveness. 3D printing has potential to modernize and streamline the denture fabrication techniques, materials and workflows. However, more research is required on the existing and developing materials and printers to allow for advancement and increase its application in removable prosthodontics.

In the following case studies we wish to discuss the necessity of making use of digital technology in the occlusion-oriented dental practice. In the three presented cases, patients underwent complex orthodontic, implant and prosthetic treatment, the aim being to re-establish the functionality of the dento-maxillary apparatus. The patients were evaluated clinically at the completion of the treatment. Subsequently, during the follow-ups (which varied between 2 and 4 years), clinical analysis using articulating paper was carried out and possible signs of relapse were specifically searched for. Occlusal clinical analysis was later on compared with the occlusion recorded using the TRIOS® 3 intraoral scanner (3Shape) and the T-Scan™ Novus™ device (TekScan). Clinical and digitally obtained scanner results were similar. The results yielded by the T-Scan™ Novus™ device were different and they were also relevant for elucidating the cause of the symptomatology.

Objectives: To assess the rate of biologic complications and implant survival in edentulous patients treated with implant-supported fixed complete dental prostheses (IFCDPs) after a mean observation period of 5.2 years (range: 1-12 years). Materials and Methods: A single-visit clinical and radiographic examination was performed to assess types and rates of biologic complications with ceramic IFCDPs (Group 1) and metal-resin IFCDPs (Group 2). Results: Of 457 rough surface dental implants supporting 71 IFCDPs (52 patients), six had failed, yielding an implant survival rate of 98.7% after a mean observation period of 5.2 years after definitive prosthesis insertion. The most frequent minor biologic complication was soft tissue recession (7.7% annual rate), inflammation under the IFCDP (7.4% annual rate), and peri-implant mucositis (6.3% annual rate). The most frequent major biologic complication was peri-implantitis (2.0% annual rate), in 46/457 implants (10.1%) supporting 19 IFCDPs and late implant failure (0.3% annual rate). The frequency of biologic complications was not statistically different between Group 1 and Group 2. The presence of high plaque index had significant effect on bone loss. Conclusions: After a mean exposure time of 5.2 years postdefinitive prosthesis insertion (range: 1-12 years), implant survival rate of 98.7% was achieved. The six implant failures in three patients occurred after 5 years and affected the prosthesis survival. Soft tissue recession was the most frequent minor biologic complication, whereas peri-implantitis was the most frequent major biologic complication. A 10year implant-based mucosal recession rate of 77% (95% CI: 68.2-87.9) and a 10-year implant-based peri-implantitis rate of 20% (95% CI: 16.9-24.9) were found. K E Y W O R D S biologic implant complications, dental implants, full arch implant prostheses, implant failure, implant fixed complete dental prostheses, implant survival

Ceramic/polymer Nano composites in the view of possessing design uniqueness and property combinations have gained a great attention and reported to be the materials of the 21st century that are not found in conventional composites. In the present work, an attempt has been made to study, develop and improve the bio-mechanic for a designed and fabricated Ceramic/polymer bio-composite for a human natural bone repair and replacement in the case of complex fracture and bone diseases by adding the Nano fillers ceramic particles to the Polymer Matrix Nano composites (PMNC) for fabricated a hybrid Titanium dioxide and yttria stabilized zirconia reinforced high density polyethylene (HDPE) matrix bio-composites properties. These bioactive composites have been investigated by using hot pressing technique at different compression pressures of (30, 60, and 90 MPa) at a compounding temperature of (180, 190, and 200 °C). The SOLIDWORKS 17.0 and the finite element ANSYS 15.7 software programs were used to the simulation, modelling and analysing of femur bone biomechanics that can withstand the highest stresses and strains. The response surface methodology (RSM) technique was used to improve and verify the results. For all the fabricated Nano bio-composites systems, the results showed that the obtained output parameters values were increased with increasing the process input parameters, also the vice versa for the strain energy and equivalent elastic strain values, also the Nano ceramic compositions represented the main factor influenced the results. The main investigates results of the current research deduced that for the increase of the Nano ceramic powder (TiO2) contain from 1% to 10%, the compression fracture strength and the micro-Vickers hardness values increased by 50% and by 8.45%, respectively, and when adding 2% of zirconia (ZrO2), an additional increase in the compression fracture strength and micro hardness by 28.21% and 40.19% achieved, respectively. When using 10% TiO2 + 2% ZrO2/HDPE bio-composite at highest compact