Dental prostheses

In edentulous individuals, flabby ridges are prevalent. In these individuals, insufficient retention and stability of a full denture are common issues. Because of its flexible tissue treatment option in such circumstances. The adoption of a liquid-supported denture in an individual with a totally edentulous maxillary arch with flabby tissue in the anterior area opposing a completely edentulous area, a liquid supported denture allows for improved stress transmission and thus gives an alternative mandibular arch is described in this case report. Esthetics were also enhanced by customising the dentures to fit the patient's lip colour.

The necessity for prostheses was as apparent in antiquity as it is today. There are two primary considerations for these devices; form and function. Form is both the aesthetics of the appliance in its own right and also how accurately the appliance replicates its natural counterpart. Function refers to how effectively the device performs its assigned task(s). With these in mind, it be will discussed whether the examples of ancient prostheses available to us today shared such considerations, and if so, in what way did benefit the physically impaired.

This study aimed to investigate residual ridge resorption (RRR) of anterior and posterior maxillary and mandibular edentulous ridges, inpatients treated with mandibular implant overdentures (IOD) and compare with conventional complete denture (CD) wearers, and to determine at each location, the association of RRR with the occlusal forces distribution and other patients' variables. The anterior and posterior RRR of IOD (six males, 17 females) and CD (12 males, 11 females) groups were determined using baseline and follow-up dental panaromic radiographs (DPT) (mean intervals 4 +/- 1<bold></bold>8years). The bone ratios were calculated using proportional area: anatomic to fixed reference areas and mean difference of ratios between the intervals determined RRR. The ridge locations included anterior and posterior maxillary and posterior mandibular arches. The T-Scan III digital occlusal system was used to record anterior and posterior percentage occlusal force (%OF) distributions. There were significant differences in anterior and posterior %OF between treatment groups. Two-way anova showed RRR was significant for arch locations (P=0<bold></bold>005), treatment group (IOD versus CD) (P=0<bold></bold>001), however, no significant interaction (P=0<bold></bold>799). Multivariate regression analyses showed significant association between RRR and %OF at anterior maxilla (P=0<bold></bold>000) and posterior mandible (P=0<bold></bold>023) and for treatment groups at posterior maxilla (P=0<bold></bold>033) and mandibular areas (P=0<bold></bold>021). Resorption was observed in IOD compared to CD groups, with 8<bold></bold>5% chance of less resorption in former and 7<bold></bold>8% in the latter location. Depending on arch location, ridge resorption at various locations was associated with occlusal force distribution and/or treatment groups (implant prostheses or conventional complete dentures).

Background: The utilization of intraoral scanning for manufacturing of complete dentures (CD) has been reported recently. However, functional border molding still cannot be supported digitally. A proof-of-concept trial shows two possible pathways to overcome this limitation by integrating a relining procedure into the digital workflow for CD manufacturing.

Two cases are reported with malpositioned implants. Both the implants were placed 6–7 months back. They
had osseointegrated well with the surrounding bone. However, they presented severe facial inclination. Case
I was restored with custom cast abutment with an auto polymerizing acrylic gingival veneer. Case II was
restored with custom cast UCLA type plastic implant abutment. Ceramic was directly fired on the custom
cast abutments. The dual treatment strategy resulted in functional and esthetic restorations despite facial
malposition of the implants.

Retrieval of cement-retained implant prostheses can be more demanding than retrieval of screw-retained prostheses. This case report describes a simple and predictable procedure to locate the abutment screw access openings of cementretained implant-supported crowns in cases of fractured ceramic veneer. A conventional periapical radiography image was captured using a digital camera, transferred to a computer, and manipulated using Microsoft Word document software to estimate the location of the abutment screw access.

Objective: The aim of this study was to investigate the effect of adding different concentrations nanoparticles of silver on color stability of acrylic resin denture base material. Materials and Methods: A total of 20 discs were used in this study, divided into 4 groups (5 each) relative to percentage of nanoparticles of silver (NAg) adding (1%, 2%and 5%) and one group without additives (control group). A double beam ultraviolet visible spectrophotometer was used to obtain diffuse reflectance data at every 5nm between 400-700nm. An integrating sphere attachment was used for the measurement. The results were recorded using a computer color matching system (CCM) and tabulated for the statistical analysis of the data. Data analysis was performed by one way ANOVA. Post Hoc test (Scheffe) was used for pair-wise comparison between the means when ANOVA test is significant. Results: Heat-cured acrylic resin with 5% nanoparticles of silver (group D) showed significantly highest mean color differences (ΔE) followed by heat-cured acrylic resin with 2% nanoparticles of silver (group C) then heat-cured acrylic resin with 1% nanoparticles of silver (group B). Heat-cured acrylic resin without additives (control group) showed significantly lowest mean color differences (ΔE). The results of color differences (ΔE) showed significant difference (P<0.05) between groups (B, C and D) and group A. Conclusion: All Groups of heat-cured acrylic resin with addition of nanoparticles of silver (NAg) showed color differences (ΔE) values higher than that control group. From a clinical point of view, the silver nanoparticles incorporation within the acrylic denture base material can be improve its color stability. (Jul 2013)

In this study robotic hands and fingers' materials are investigated from past to present and a sponge robotic hand is designed for biomedical applications. Emergence and necessity of soft robotic technology are explained and description of soft robot is made. Because of the importance of hand in a person's body, researchers have dealt with robotic hand prostheses for many centuries and developed many hand types. To mimic the best for the human limbs, softness of the hand is one of the important features. Recent studies are summarized in a table. In the table you can see materials that are used in robotic hand and fingers; they are classified as soft and rigid with their years. In literature sponge was found as the most suitable material for the fingers, but there is no study about a sponge hand. This study aims to fill this gap in literature. In this paper manufacturing of a Sponge Robotic Hand's production parameters and stages are explained clearly. Finally advantages of sponge robotic hand and future studies about sponge robotic hand are mentioned.

Purpose - The purpose of this paper is to highlight the significance of placing identification marks on dentures. Design/methodology/approach - This paper reviews the legislation with regard to denture marking in certain countries, various methods of denture marking and describes a simple, inexpensive, paper-based labelling system. Findings - Various methods have been proposed for denture marking but it is important to use a method that is simple, practical, affordable and universally acceptable. Practical implications - The identification of unknown or missing persons by means of denture marking is a very successful method of identification in forensic investigation. It is also useful for patients residing in hospitals and community homes where dentures could be misplaced, particularly during cleaning by personnel where there is a chance of loss or mix-up. The importance of denture marking should be emphasized by all law-enforcing authorities and should be promoted among all dentists, towards making it a compulsory routine dental procedure throughout the world. Originality/value - In Malaysia, denture marking, as recommended by its Ministry of Health, uses a unique coding system which can readily provide information about the wearer in whichever part of the world the person is found. The method applied is simple, practical and affordable and can easily be adapted by others. It can be of great value during times of crisis.

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

Statement of problem. Despite the broad clinical application of zirconia for fixed implant-supported prostheses, evidence of long-term performance is sparse.
Purpose. The purpose of this retrospective study was to evaluate the long-term clinical and radiographic outcomes of zirconia-based partial and complete screw-retained implant-supported zirconia fixed dental prostheses (ISZFDPs).
Material and methods. Records of patients treated with dental implants and ISZFDPs between December 2004 and June 2017 were screened. Eligible study participants, according to inclusion criteria, were contacted and invited to undergo clinical and radiographic examinations. Outcomes were evaluated as implant and prosthetic survival rates, prosthetic success rate, complications, marginal bone level (MBL) change, and soft tissue condition. Along with the effects of zirconia prosthesis type and level, the effects of implant type and connection, type of loading, and follow-up on MBL were tested with a generalized linear effects model (GLEM) (a=.05).
Results. A total of 118 patients were identified, of whom 20 (16.9%) were not available for clinical examination for various reasons. Ninety- eight participants (mean age 60.7 ±11.7 years) with 337 implants were included, of which 176 (52.2%) had been immediately loaded. A total of 111 ISZFDPs (96 zirconia connection and 15 titanium base) were investigated: 24 complete ISZFDPs with a zirconia connection (12.9 ±0.97 dental units, minimum 12, maximum 14), 72 partial with a zirconia connection (3.11 ±1.12, minimum 2, maximum 7), 15 partial with a titanium base (3.62 ±1.02, minimum 2, maximum 5). Forty ISZFDPs had been in function for !10 years (36%), 38 for 5 to 9 years (34.2%), and 33 for 2 to 4 years (22.8%). The mean follow-up time was 7.2 ±3.4 years. No zirconia fractures were identified. Two implants and 2 ISZFDPs failed, with chipping being the most common complication (13.5%). The implant survival rate was 99.4%, and the prosthetic survival rate was 98.2%. The cumulative prosthetic success rate was 91.9%. MBL change was -0.18 ±0.59 mm. Thirteen implants were treated for peri-implantitis (3.8%), and 9 for mucositis (2.7%), but presented healthy peri-implant soft tissues at the follow-up examination. A significant difference was found between the implant-level and abutment-level prostheses (P=.013), with less marginal bone loss observed in ISZFDPs delivered at the implant level.
Conclusions. Zirconia-based screw-retained implant-supported prosthesis can be considered a reliable long-term treatment option for partial and complete edentulism. No zirconia fractures were experienced. Stable bone levels and low peri-implantitis rates were reported regardless of the ISZFDP type and level, implant type and connection, and type of loading.

Purpose: The purpose of this in vitro study was to measure the loss of retention and wear of two clasp types (E-circlet, back action) against three abutment materials (enamel, composite, CAD/CAM ceramic) after 16,000 simulated cycles of attachment-detachment. Materials and Methods: Forty-eight models were constructed by placing either an upper first premolar or a metal die inside a metal rectangular block. Models were divided according to the abutment teeth into three groups. Group E consisted of 16 un-restored human premolars with sound enamel. Group R had 16 premolars recontoured buccally using composite resin. Group C had 16 metal dies (duplicated from a human premolar) covered by CAD/CAM all-ceramic crowns. On the models, E-circlet (E) and back-action (B) clasps were constructed to engage the model's teeth. Withdrawal and insertion cycling of clasps was carried out for 16,000 cycles by using a chewing simulator. The retention force of each clasp was measured after cycling. An acrylic replica was made for each abutment retention surface before and after cycling. Each replica was examined by SEM, and the wear areas were measured. The data were analyzed statistically using one-way ANOVA, two-way ANOVA, and Mann-Whitney tests. Results: There was no significant retention loss after 16,000 cycles (p ≥ 0.05) of both clasps (E, B) on the three abutment materials (E, R, C). The mean of wear areas in mm 2 were 1.83 ± 0.36, 0.85 ± 0.66, 2.37 ± 1.88, 1.7 ± 1.11, 0.6 ± 0.2, and 0.06 ± 0 for EE, BE, ER, BR, EC, and BC, respectively. There were significant differences among the wear areas of the abutment surface of the six subgroups (p ≤ 0.05). Conclusion: The composite resin contoured surfaces showed more wear than the enamel and ceramic surfaces. E-clasps caused more wear on the abutment materials than back-action clasps.

Objectives: To evaluate the retention and wear behavior for different designs of precision attachments. Materials and Methods: Fifteen specimens of OT attachments castable system (Rhein83) with three different designs with plastic female parts and metal alloy male parts were selected. The specimens divided into three different designs groups; group I containing OT cap attachments, group II containing OT vertical attachments and group III containing OT strategy attachments. Each specimen subjected to 1200 wear cycle in a universal testing machine. Each cycle had performed full insertion/separation movement in an axial direction at a cross head speed of 50 mm/min in the presence of artificial saliva; and the retentive force had been measured at different thirteen intervals. Before and after testing, each one of the polymeric retentive female parts (caps and clips) had been individually weighted and scanned by SEM using low vacuum mode to detect loss of material and worn areas. Results: One-way ANOVA test revealed that there was a statistically significant difference between the groups (P<0.001). Pair-wise comparisons between the groups showed that; group II (OT vertical) showed the highest mean weight and retention loss followed by group I (OT cap) then group III (OT strategy). All designs subjected to wear but only OT vertical (group II) attachments have showed marked wear and retention loss. Conclusion: The designs of attachments have an important role in wear process. OT cap attachments and OT strategy attachments showed slight wear and material loss in comparison to OT vertical attachments.

Objectives: The study aimed to evaluate and compare the dental prosthetic status and treatment needs of adult population in Jizan, Saudi Arabia, in relation to the age. Materials and Methods: A total of 1779 people aged 35–74 years from 4 survey areas (Hay al matar, Mahata khams, Dara ut tawhid, and Suq ad dakhili) selected through convenient sampling, around Jizan University, were surveyed, using the WHO survey criteria, 1997. Statistical Analysis: Number and percentages were calculated, and univariate analysis was performed using Chi-square test at 5% level of significance. Results: Different forms of prosthesis were present among patients in the upper (19.9%) and lower (19%) arches, respectively. Prosthetic treatment need was recognized in subjects, 56.4% for the upper and 57.2% for the lower arches, respectively. The prosthetic status and treatment needs differed statistically with respect to age. Conclusion: More than half of the surveyed adult populations were in need of some or the other forms of prosthesis. This study provides data for an oral health-care provider program for Jizan.

Implant-retained mandibular ball-supported and bar-supported overlay dentures are the two most common treatment options for the edentulous mandible. The superior option in terms of strain distribution should be determined. The three-dimensional model of mandible (based on computerized tomography scan) and its overlying implant-retained bar-supported and ball-supported overlay dentures were simulated using SolidWorks, NURBS, and ANSYS Workbench. Loads A (60 N) and B (60 N) were exerted, respectively, in protrusive and laterotrusive motions, on second molar mesial, first molar mesial, and first premolar. The strain distribution patterns were assessed on (1) implant tissue, (2) first implant-bone, and (3) second implant-bone interfaces. Protrusive: Strain was mostly detected in the apical of the fixtures and least in the cervical when bar design was used. On the nonworking side, however, strain was higher in the cervical and lower in the apical compared with the working side implant. Laterotrusive: The strain values were closely similar in the two designs. It seems that both designs are acceptable in terms of stress distribution, although a superior pattern is associated with the application of bar design in protrusive motion.

Background: In studies comparing different prosthetic treatment concepts the repeated loss of teeth was chosen as the primary outcome. The resulting data appear to represent a data structure of recurrent events. However, the application of an existing method for recurrent events is far from straightforward. Often only the first event or the final state is analyzed using Kaplan–Meier survival statistics, thereby giving a great deal of information away. Methods: The paper presents a strategy for the analysis of recurrent data using a previously published study on the influence of different prosthetic treatment concepts for the shortened dental arch on tooth loss. A method based on cumulative sample history functions of recurrent events was adjusted for tooth loss. The shapes of these cumulative functions suggest a time dependency of the recurrence rate. To keep the model as simple as possible, a tripartite Poisson process (which assumes piecewise time-independent rates) was fitted to the cumulative mean functions stratified by treatment. Results: Within the middle interval of the three-phasic process, the treatment effects differ significantly, which is interpreted as a delay of tooth loss due to the use of one type of prosthesis (fixed) compared with the other (removable). Conclusions: An analysis based on cumulative history functions is based on process, therefore, temporally changing characteristics are better captured than in methods for survival analyses. The presented approach offers useful new insight into the temporal behavior of ongoing tooth loss after prosthetic treatment. Trial registration: The trial has been registered at controlled-trials.com under ISRCTN97265367 (registration date 4

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((R))) 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 degreesC 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 control and disinfected groups, the flexural modulus of nylon was significantly lower than the three PMMA polymers. The flexural strength of nylon was significantly lower than those of Meliodent and Acron MC but was comparable with Lucitone 199. A 24-h immersion in the disinfecting solution increased the rigidity of nylon denture base material.

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.

A master cast representing a completely edentulous mandible was fabricated in polyurethane resin and had four implants secured to the anterior interforaminal area. Impressions were made using six technique-material combinations. Ten definitive casts were fabricated for each technique. Linear distances between implants were measured using a traveling microscope. There was no statistically significant difference between the direct unsplinted and splinted techniques (P >. 05), while the indirect technique was statistically significantly different from the other two techniques (P <. 05). There was no statistically significant difference between the two impression materials.

Aims: To evaluate the reliability and reproducibility and calculating arch discrepancy measurement using cone-beam computed tomography (CBCT) and comparing it to measurements obtained using the 2D Digital Method.
Material and Methods: Traditional dental plaster casts were obtained from 50 patients and then digitalized, so as to be able to measure them using the Digital Method. Likewise, CBCTs were undertaken on those same patients using the Dental Picasso Master 3D® and the images obtained analysed using the InVivoDental program.
Results: Determining the regression lines from both measuring methods, as well as the difference in values between them, shows how the two methods are comparable, despite the fact that the measurements analysed presented statistically significant differences.
Conclusions: The three-dimensional models obtained from the CBCT are as accurate and reproducible as the digital models obtained from plaster casts for calculating arch discrepancy measurement. The differences existing between both methods were clinically acceptable.

OBJECTIVE: The objectives of this study were to compare the effects of a newly designed magnetic suspension system with that of two existing suspension methods on pistoning inside the prosthetic socket and to compare satisfaction and perceived problems among transtibial amputees. DESIGN: In this prospective study, three lower limb prostheses with three different suspension systems were fabricated for ten transtibial amputees. The participants used each of the three prostheses for 1 mo in random order. Pistoning inside the prosthetic socket was measured by motion analysis system. The Prosthesis Evaluation Questionnaire was used to evaluate satisfaction and perceived problems with each suspension system. RESULTS: The lowest pistoning motion was found with the suction system compared with the other two suspension systems (P < 0.05). The new suspension system showed peak pistoning values similar to that of the pin lock system (P = 0.086). The results of the questionnaire survey revealed significantly higher satisfaction rates with the new system than with the other two systems in donning and doffing, walking, uneven walking, stair negotiation, and overall satisfaction (P < 0.05). CONCLUSIONS: The new suspension system has the potential to be used as an alternative to the available suspension systems. The pistoning motion was comparable to that of the other two systems. The new system showed compatible prosthetic suspension with the other two systems (suction and pin lock). The satisfaction with donning and doffing was high with the magnetic system. Moreover, the subjects reported fewer problems with the new system. Copyright © 2012 by Lippincott Williams & Wilkins.

http://graphics.tx.ovid.com/ovftpdfs/FPDDNCLBPCEOKH00/fs047/ovft/live/gv024/00002060/00002060-201212000-00003.pdf 
http://www.ncbi.nlm.nih.gov/pubmed/23168378

One of the main issues facing dental implantation, which makes osseointegration and bone remodeling problematical, is a mismatch of mechanical properties between engineered and native biomaterials. Functionally Graded Materials (FGMs) has been proposed as a potential alternative to some conventional implant materials such as titanium for selection in prosthetic dentistry. The idea of FGM dental implant is that the property would vary in a certain pattern to match the biomechanical characteristics required at different regions in the hosting bone. This research presents some important findings for the FGM dental implant design in optimization of material gradient. Due to the nature of the problem, multi-objective optimization methods should apply for solving multi-criteria problems. The Pareto front was determined using the Multi-Objective Particle Swarm Optimization (MOPSO). The obtained results from the MOPSO confirm the results obtained by the Response Surface Methodology (RSM) in addition to offering further improvements.

http://www.scientific.net/AMR.647.30