scholarly journals Do we know how much force we apply with latex intermaxillary elastics?

2021 ◽  
Vol 11 ◽  
pp. 191-197
Author(s):  
Berza Sen Yilmaz ◽  
Mihriban Kara ◽  
Elif Dilara Seker ◽  
Deniz Yenidünya
Keyword(s):  
Room Temperature ◽  
Lumen Diameter ◽  
Aqueous Environment ◽  
Distilled Water ◽  
Force Level ◽  
Force Measurements ◽  
Second Molar ◽  
Know How ◽  
Custom Made ◽  
Significant Difference

Objectives: The aim of our study was to evaluate the variation of the forces provided by different branded elastics and to compare the force diminution that occurs after 24-h of use in wet environment. Materials and Methods: Elastics from four different manufacturer (American Orthodontics [AO], USA; Dentaurum [DENT], Germany; Ormco, USA; RMO, USA) with 3/16-inch (4.8 mm) lumen diameter, and two different force degrees (medium/heavy) were included in the study with a total of eight groups of elastics. First force measurements were performed with 50 elastics of each group at various stretching distances; lumen diameter ×2 (9.52 mm), ×3 (14.28 mm), the average canine-first molar length (22.3 mm), and the canine-second molar length (38.7 mm) under room temperature and dry air conditions. In addition, ten the elastics from each group were stretched at 22.3 mm distance in a custom-made plate and kept in 37°C distilled water. Twenty-four hours later, the force measurements were repeated. Results: Regardless of the brand and type (medium-heavy), all the tested elastics showed variations in matter of generated forces at different stretching distances. The variation amount increased as the length of elongation increased. The lowest standard deviation values were observed for both medium and heavy DENT elastic groups. When stretched to 3 times of their lumen size, the medium and heavy elastics both produced either lower or higher forces compared to the levels of force indicated by the manufacturers. The closest mean force to the force level stated by the manufacturer was provided with medium AO (3.6 g difference) elastics and heavy RMO counterparts (7.9 g difference). A significant 20–23% reduction of force was observed in all brands, both in medium and heavy elastics after passing 24-h in aqueous environment. No significant difference was observed in matter of force degradation between groups for both medium and heavy elastics (P < 0.05). Conclusion: The forces exerted by intermaxillary elastics were not found to be standard and the force stated on the package is not always provided precisely. A significant force loss around 20% was observed with all the elastics after 24-h of use in wet environment at 37°C.

scholarly journals The effect of temperature change on fluoride uptake from a mouthrinse by enamel specimens

2012 ◽  
Vol 06 (04) ◽  
pp. 361-369 ◽  
Author(s):  
Serdar Baglar ◽  
Adil Nalcaci ◽  
Mustafa Tastekin
Keyword(s):  
Body Temperature ◽  
Room Temperature ◽  
Hot Water ◽  
Effect Of Temperature ◽  
Distilled Water ◽  
Fluoride Solution ◽  
Fluoride Uptake ◽  
Significant Difference ◽  
Human Body Temperature ◽  
Different Temperatures

ABSTRACTObjective: The aim of this study was to examine the effect of temperature on fluoride uptake by enamel specimens from a 0.05% NaF-fluoridated mouthrinse (Oral-B Advantage; Oral-B Laboratories, Newbridge, UK).Methods: Enamel specimens were prepared from extracted human maxillary central incisors. A fluoride-specific ion electrode was used to measure the uptake from a 2 ppm fluoride solution containing 50.0 mL of distilled water, total ion strength adjustment buffer, and fluoridated rinse at 3 different temperatures (room temperature, 25°C; human body temperature, 37°C; hyper-fever temperature, 43°C). One-way analysis of variance and least significant difference were used to assess intragroup and intergroup differences (P<.05).Results: The study found that both the amount and the rate of fluoride uptake increased significantly with increase in temperature. This effect was particularly noticeable at 43°C.Conclusions: The temperature of the NaF mouthrinse may easily and safely be increased beyond room temperature by placing a container of the NaF mouthrinse in a bowl of hot water, allowing greater fluoride penetration into the enamel from the mouthrinse when used at home as a routine prophylactic agent. (Eur J Dent 2012;6:361-369)

scholarly journals Changes in Factor VIII:C Activity over 24 Hours Depending on Diluent and Storage Conditions after Dilution

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2488-2488
Author(s):  
Shin Young Hyun ◽  
Kun soo Lee ◽  
Yu Ri Kim
Keyword(s):  
Factor Viii ◽  
Normal Saline ◽  
Room Temperature ◽  
Conflicts Of Interest ◽  
Distilled Water ◽  
Factor Viii Activity ◽  
Fviii Activity ◽  
Significant Difference ◽  
Over Time

Abstract Background : Continuous infusion of factor VIII (FVIII) is a more cost-effective method for treating hemophilia A than intermittent bolus injection, especially when undergoing surgery. The activity of the factor 8 concentrates may gradually decreases over 24 hours at room temperature, making it difficult to maintain a desired appropriate blood concentration. However, there are no specific guidelines for precise method and duration of continuous intravenous. administration of factor VIII products. In this study, we evaluate in vitro factor VIII activity during 24 hours after reconstitution with diluent fluid in various conditions to propose an effective continuous i.v. infusion method. Method : A total 6 of coagulation factor VIII concentrates were used (2 plasma derived FVIII products and 4 recombinant FVIII products) - Greengene-F®,Advate®, Xyntha®, monoclateP®, Koginate®,Immunate®. Each drug was dissolved in the enclosed water for injection according to the manufacturer's instruction. After 30 minutes of stabilizing, each drug was further diluted in sterilized distilled water or normal saline or dextrose water was adjusted to the same concentration for this experiment. Then, the drugs were stored at refrigeration or room temperature with exposure to light or light-shielded. In vitro FVIII:C was measured at five time points (0, 2, 4, 6, 8, and 24 hours after reconstitution) with a one-stage clotting assay a CS5100 coagulation analyzer system from Sysmex. Then, the factor VIII activity of each time was statistically compared with activity of 0 hour. Results: With all experimental conditions, FVIII activities of all 6 drugs persistently decreased over the course of 24 hours (p <0.001). There was a significant difference in the degree of decrease in activity over time depending on the type of drug (p <0.001), the activity after 2 hours is 47.58 to 90.76 %, the activity after 4 hours is 31.58 to 86.21 %, the activity after 8 hours is 6.49 to 77.03 %, the activity after 18 hours is 2.24 to 75.49 %, the activity after 24 hours is 1.23 to 73.63%. Two hours after the dilution, the FVIII activity decreased to 80% or less with 3 of 6 drugs. After 4 hours, 5 of 6 drugs had the FVIII activity of 80% or less, and after 6 hours the FVIII activity decreased to less than 80% in all of 6 drugs. There was a difference in the degree of decrease in activity depending on the presence or absence of shading and refrigeration, and diluent solutions (normal saline or dextrose water instead of distilled water), but there was a difference between the drugs and consistent correlation was not observed. Conclusions : When the FVIII concentrates were diluted, the activity of each of the six drugs decreased significantly over the 24 hours in vitro, and the degree of decrease was significantly different according to the exposed conditions although there was a difference by drug. Based on the results of the continuous decrease in FVIII activity over time, it is not appropriate to dissolve a 24-hour dose in a large amount of diluted fluid at one time and continuously infuse during 24 hours. Replacing the concentrate before 2 to 6 hours after dilution is probably a better method to maintain desired FVIII activity in patients with hemophilia. Disclosures No relevant conflicts of interest to declare.

Effect of Placement Agitation and Placement Time on the Shear Bond Strength of 3 Self-etching Adhesives

10.2341/05-52 ◽  
2006 ◽  
Vol 31 (4) ◽  
pp. 426-430 ◽  
Author(s):  
L. M. Velasquez ◽  
R. S. Sergent ◽  
J. O. Burgess ◽  
D. E. Mercante
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Room Temperature ◽  
Distilled Water ◽  
Application Time ◽  
Bonding Agents ◽  
Crosshead Speed ◽  
Occlusal Surfaces ◽  
Significant Difference ◽  
Wet Ground

SUMMARY This study measured the shear bond strength (SBS) of 3 self-etching bonding agents to enamel and dentin with and without agitation at 3 different application times. The null hypotheses tested were that agitation and application time have no effect on bond strength. Occlusal surfaces of 180 recently extracted caries-free human molars were wet ground with 600 grit wet-dry silica carbide abrasive paper to obtain a flat enamel surface. The teeth were divided into 18 groups of 10 teeth. Three self-etching bonding agents, Clearfil SE BOND (Kuraray America), Xeno III (Dentsply) and AdheSE (Ivoclar-Vivadent) were applied using application times of 10, 20 or 30 seconds with or without agitation, thinned with a gentle stream of air and cured for 10 seconds, according to manufacturers' directions. Z100 (3M ESPE) composite, A2 shade, was placed over the cured adhesive and cured for 40 seconds. The samples were stored in distilled water at room temperature until testing. The samples were tested in shear to failure with a 1-mm/minute crosshead speed. After enamel shear bond strength testing, the teeth were again ground with 400 and 600-grit wet-dry SiC paper to obtain a flat dentin surface. The protocol used for preparing the enamel bond test samples was repeated, and the teeth were stored until testing in distilled water at room temperature. The samples were again tested in shear at a 1-mm/minute crosshead speed. Values were converted to MPa and data analyzed for intergroup differences using ANOVA and Tukey post-hoc tests. Agitation did not improve enamel SBS for any of the materials tested, but there was a significant difference in enamel SBS among materials: Clearfil SE Bond shear bond strength was greater than Xeno III, which was greater than AdheSE. At 10 seconds application time on dentin, agitation improved the Clearfil SE Bond SBS and, at 20 seconds application time on dentin, agitation significantly improved SBS to dentin for all systems tested. Agitation had no affect when the adhesive was applied to dentin for 30 seconds. Clearfil SE Bond SBS to dentin was significantly higher than the other self-etching adhesives tested except at 10 seconds without agitation.

Degradation of AlN Powder in Aqueous Environments

2004 ◽  
Vol 19 (4) ◽  
pp. 1157-1163 ◽  
Author(s):  
Kristoffer Krnel ◽  
Goran Dražič ◽  
Tomaž Kosmač
Keyword(s):  
Incubation Time ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Low Ph ◽  
Aqueous Environment ◽  
Distilled Water ◽  
Ph Values ◽  
Powder Concentration ◽  
Aqueous Environments ◽  
Hydrolysis Of

The reactivity of AlN powder in an aqueous environment was studied by measuring the pH and the temperature during the hydrolysis of the powder at room and elevated temperatures. The influences of the powder concentration and the starting pH of the slurry were also investigated. The results of the measurements at room temperature show that there is an incubation time before the start of the AlN hydrolysis reactions. Once this incubation time is over, the pH and the temperature of the slurry start to increase, indicating the onset of the reactions. A higher starting temperature not only speeds up the reaction of the AlN powder with water, but it also shortens the incubation time. In addition, the starting temperature influences the morphology of the reaction product: at temperatures below 60 °C, the final product of the hydrolysis is crystalline Al(OH)3, whereas at higher temperatures (above 60 °C), crystalline AlOOH is formed. At very low pH values (pH = 1), the reaction of AlN powder with water is prevented (i.e., the incubation time is very long), whereas in an alkaline environment, the incubation time is approximately the same as in distilled water, but the reaction is accelerated.

Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

1970 ◽  
Vol 28 ◽  
pp. 114-115
Author(s):  
P. A. Madden ◽  
W. R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Freeze Drying ◽  
Room Temperature ◽  
Secondary Electron ◽  
Distilled Water ◽  
Freeze Dried ◽  
Silver Paint ◽  
To Come ◽  
Scanning Electron

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.

Axial Triangle of the Maxillary Sinus, and its Surgical Implication With the Position of Maxillary Sinus Septa During Sinus Floor Elevation: A CBCT Analysis

2020 ◽  
Vol 46 (4) ◽  
pp. 415-422
Author(s):  
Junho Jung ◽  
Jung Soo Park ◽  
Seoung-Jin Hong ◽  
Gyu-Tae Kim ◽  
Yong-Dae Kwon
Keyword(s):  
Maxillary Sinus ◽  
Surgical Techniques ◽  
Lateral Sinus ◽  
Sinus Floor Elevation ◽  
Second Molar ◽  
Sinus Wall ◽  
Posterior Maxilla ◽  
Significant Difference ◽  
Sinus Floor ◽  
Molar Region

The aim of this study was to measure the convexity of the lateral wall of the maxillary (Mx) sinus and identify the locational distribution of antral septa in relation to the zygomaticomaxillary buttress (ZMB), in order to suggest another anatomical consideration and surgical modification of sinus floor elevation procedures. This study was designed as a cross-sectional study, and a total of 134 patients and 161 sinuses containing edentulous alveolar ridges were analyzed. The angle between the anterior and lateral walls of the Mx sinus (lateral sinus angle [LSA]), and the angle between the midpalatal line and the anterior sinus wall (anterior sinus angle [ASA]) were measured. Mean LSAs and ASAs were 105.9° ± 9.86° and 58.4° ± 6.43°, respectively. No significant difference between left and right sides was found (LSA, P = .420; right = 105.5° ± 9.27°; left = 105.5° ± 9.27° and ASA, P = .564; right = 57.9° ± 6.80°; left = 58.8° ± 6.02°). The prevalence of septa was 37.3%, and it was most frequently noted in the second molar region (32.8%), followed by the first molar (20.9%), retromolar (16.4%), and second premolar regions (14.9%). Septa were most frequently located posterior to the ZMB (49.2%), while ZMB was mostly located in the first molar region (66.4%). Narrow LSAs may complicate the surgical approach to the posterior maxilla, especially when sinus elevation should be used in the second molar region. Considering the occasional presence of antral septa, membrane elevation may be complicated when a septum is encountered during the procedure. These results suggest that 3-dimensional examination of the convexity of the Mx sinus should be performed preoperatively to choose proper surgical techniques and minimize surgical complications.

Properties of Gliricidia Wood (Gliricidia sepium) lntercropped with Cocoa (Theobroma cocoa) in Malaysia

2014 ◽  
Vol 11 (1) ◽  
pp. 51
Author(s):  
Mohd Helmy Ibrahim ◽  
Mohd Nazip Suratman ◽  
Razali Abd Kader
Keyword(s):  
Cell Wall ◽  
Specific Gravity ◽  
Moisture Content ◽  
Wall Thickness ◽  
Age Groups ◽  
Gliricidia Sepium ◽  
Cell Wall Thickness ◽  
Tree Age ◽  
Lumen Diameter ◽  
Significant Difference

Trees planted from agroforestry practices can become valuable resources in meeting the wood requirements of many nations. Gliricidia sepium is an exotic species introduced to the agricultural sector in Malaysia mainly for providing shade for cocoa and coffee plantations. This study investigates its wood physical properties (specific gravity and moisture content) and fibre morphology (length, lumen diameter and cell wall thickness) of G. sepium at three intervals according to age groups ( three, five and seven years of ages). Specific gravity (0.72) was significantly higher at seven years ofage as compared to five (0.41) and three (0.35) years age group with a mean of 0.43 (p<0.05). Mean moisture content was 58.3% with no significant difference existing between the tree age groups. Fibre diameter (22.4 mm) was significantly lower (p<0.05) for the trees which were three years of age when compared to five and seven years age groups (26.6 mm and 24. 7 mm), respectively. Means of fibre length, lumen diameter and cell wall thickness were 0.83 mm, 18.3 mm, and 6.2 mm, respectively, with no significant differences detected between trees in all age groups. Further calculation on the coefficient of suppleness and runkel ratio suggest that wood from G.sepium may have the potential for insulation board manufacturing and paper making. However, future studies should experiment the utilisation of this species for these products to determine its full potential.

Effect of Temperature on Oil/Water Relative Permeabilities of Unconsolidated and Consolidated Sands

1985 ◽  
Vol 25 (06) ◽  
pp. 945-953 ◽  
Author(s):  
Mark A. Miller ◽  
H.J. Ramey
Keyword(s):  
Relative Permeability ◽  
Room Temperature ◽  
Water Saturation ◽  
High Water ◽  
Distilled Water ◽  
Relative Permeabilities ◽  
Two Phase ◽  
Dynamic Displacement ◽  
Irreducible Water Saturation ◽  
Increasing Temperature

Abstract Over the past 20 years, a number of studies have reported temperature effects on two-phase relative permeabilities in porous media. Some of the reported results, however, have been contradictory. Also, observed effects have not been explained in terms of fundamental properties known to govern two-phase flow. The purpose of this study was to attempt to isolate the fundamental properties affecting two-phase relative permeabilities at elevated temperatures. Laboratory dynamic-displacement relative permeability measurements were made on unconsolidated and consolidated sand cores with water and a refined white mineral oil. Experiments were run on 2-in. [5.1-cm] -diameter, 20-in. [52.-cm] -long cores from room temperature to 300F [149C]. Unlike previous researchers, we observed essentially no changes with temperature in either residual saturations or relative permeability relationships. We concluded that previous results may have been affected by viscous previous results may have been affected by viscous instabilities, capillary end effects, and/or difficulties in maintaining material balances. Introduction Interest in measuring relative permeabilities at elevated temperatures began in the 1960's with petroleum industry interest in thermal oil recovery. Early thermal oil recovery field operations (well heaters, steam injection, in-situ combustion) indicated oil flow rate increases far in excess of what was predicted by viscosity reductions resulting from heating. This suggested that temperature affects relative permeabilities. One of the early studies of temperature effects on relative permeabilities was presented by Edmondson, who performed dynamic displacement measurements with crude performed dynamic displacement measurements with crude and white oils and distilled water in Berea sandstone cores. Edmondson reported that residual oil saturations (ROS's) (at the end of 10 PV's of water injected) decreased with increasing temperature. Relative permeability ratios decreased with temperature at high water saturations but increased with temperature at low water saturations. A series of elevated-temperature, dynamic-displacement relative permeability measurements on clean quartz and "natural" unconsolidated sands were reported by Poston et al. Like Edmondson, Poston et al. reported a decrease in the "practical" ROS (at less than 1 % oil cut) as temperature increased. Poston et al. also reported an increase in irreducible water saturation. Although irreducible water saturations decreased with decreasing temperature, they did not revert to the original room temperature values. It was assumed that the cores became increasingly water-wet with an increase in both temperature and time; measured changes of the IFT and the contact angle with temperature increase, however, were not sufficient to explain observed effects. Davidson measured dynamic-displacement relative permeability ratios on a coarse sand and gravel core with permeability ratios on a coarse sand and gravel core with white oil displaced by distilled water, nitrogen, and superheated steam at temperatures up to 540F [282C]. Starting from irreducible water saturation, relative permeability ratio curves were similar to Edmondson's. permeability ratio curves were similar to Edmondson's. Starting from 100% oil saturation, however, the curves changed significantly only at low water saturations. A troublesome aspect of Davidson's work was that he used a hydrocarbon solvent to clean the core between experiments. No mention was made of any consideration of wettability changes, which could explain large increases in irreducible water saturations observed in some runs. Sinnokrot et al. followed Poston et al.'s suggestion of increasing water-wetness and performed water/oil capillary pressure measurements on consolidated sandstone and limestone cores from room temperature up to 325F [163C]. Sinnokrot et al confirmed that, for sandstones, irreducible water saturation appeared to increase with temperature. Capillary pressures increased with temperature, and the hysteresis between drainage and imbibition curves reduced to essentially zero at 300F [149C]. With limestone cores, however, irreducible water saturations remained constant with increase in temperature, as did capillary pressure curves. Weinbrandt et al. performed dynamic displacement experiments on small (0.24 to 0.49 cu in. [4 to 8 cm3] PV) consolidated Boise sandstone cores to 175F [75C] PV) consolidated Boise sandstone cores to 175F [75C] with distilled water and white oil. Oil relative permeabilities shifted toward high water saturations with permeabilities shifted toward high water saturations with increasing temperature, while water relative permeabilities exhibited little change. Weinbrandt et al. confirmed the findings of previous studies that irreducible water saturation increases and ROS decreases with increasing temperature. SPEJ P. 945

scholarly journals An Assessment of Treated Greywater Reuse in Irrigation on Growth and Protein Content of Prosopis and Albizia

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 38
Author(s):  
Naji K. Al-Mefleh ◽  
Yahia A. Othman ◽  
Maher J. Tadros ◽  
Amani Al-Assaf ◽  
Samer Talozi
Keyword(s):  
Protein Content ◽  
Crude Protein ◽  
Dry Weight ◽  
World Health ◽  
Quality Analysis ◽  
Distilled Water ◽  
Albizia Lebbeck ◽  
Forage Production ◽  
Water Control ◽  
Significant Difference

This study investigated the influence of treated greywater on growth and protein content of multipurpose (forage and ornamental) transplants, Prosopis juliflora L., Prosopis tamarugo L., and Albizia lebbeck L. Transplants of tested species were irrigated with treated greywater, diluted greywater (grey + distilled water, 1:1/by volume), and distilled water (control) for seven months. Water quality analysis showed that the concentrations of nutrients and heavy metals found in the greywater were within the acceptable range compared with Jordan Institution for Standard and Metrology (JISM) and the World Health Organization (WHO) thresholds for safe use of greywater. Escherichia coli found in the greywater were lower compared to JISM and WHO guidelines for the safe use of greywater. Irrigation with treated greywater increased shoot fresh weight by 24–39% and dry weight by 34–40% compared to diluted greywater and control. No significant difference in crude protein was noticed between water treatments. Prosopis species (P. juliflora Albizia lebbeck L. and P. tamarugo Albizia lebbeck L.) had higher shoot fresh (35%) and dry weight the same species had lower crude protein (44%) when compared to Albizia lebbeck Albizia lebbeck L. The reuse of treated greywater for landscaping or forage production alleviates the demand for water resources and reduces the pressure on wastewater treatment plants. However, considering the controversial findings of previous studies on greywater quality (especially, long-term reuse), the reuse of treated greywater needs to be considered with caution and periodic quality analyses and economic assessments are required.

scholarly journals Influence of rigidity of retainers on dynamic behavior of implant-supported removable partial dentures

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Toshifumi Nogawa ◽  
Masayasu Saito ◽  
Naomichi Murashima ◽  
Yoshiyuki Takayama ◽  
Atsuro Yokoyama
Keyword(s):  
Dynamic Behavior ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Denture Base ◽  
Second Molar ◽  
Mechanical Simulation ◽  
Computed Tomography Images ◽  
Significant Difference ◽  
Abutment Teeth ◽  
Distal Extension

Abstract Background Implant-supported removable partial dentures (ISRPDs) are an effective treatment for partially edentulous patients. ISRPDs improve patients’ satisfaction and oral function to a greater extent than RPDs by improving denture stability and enhancing support. However, the effect of a type of direct retainer on displacement of the abutment teeth and dentures in ISRPDs remains unclear. Therefore, we made a resin mandibular model of unilateral mandibular distal-extension partial edentulism for mechanical simulation and compared the dynamic behavior of the abutment teeth and the denture base among different tooth-borne retainers with various rigidities for RPDs and ISRPDs. Methods A resin mandibular model for mechanical simulation that had unilateral mandibular distal-extension edentulism and was missing the first molar, second molar, first premolar, and second premolar, and a denture fabricated from the patient’s computed tomography images were used. Three types of direct retainers with different connecting rigidities were evaluated. The vertical displacement of the denture base and buccal and lingual sides and the mesial displacement of the abutment teeth were measured. Results Regardless of the rigidity of the direct retainers and loading positions, the displacement of the denture bases in the ISRPDs was significantly smaller than that in the RPDs (P < 0.001). There was no significant difference in vertical displacement of the denture bases among direct retainers with various connecting rigidities in the ISRPDs. Conversely, horizontal displacement of the abutment teeth in both the RPDs and ISRPDs tended to be larger with the cone crown telescope, which has high rigidity, than with the cast cingulum rest and wire clasp, which have much lower rigidities. Conclusion Our results suggested that cast cingulum rest and wire clasps as direct retainers are appropriate ISRPDs to minimize denture movement and suppress displacement of the remaining teeth in patients with unilateral mandibular distal-extension partial edentulism.

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