Assessment the retentive force and XRD analysis on the recycling esthetic thermoplastic acetal clasps / Avaliação da força de retenção e análise de DRX dos grampos de resina estética termoplástica acetal reciclada

Objective: To reduce environmental biohazards, technicians should be educated with safe biological waste disposal procedures and dental material recycling. The present study assesses the retentive force, deformation test and XRD analysis of re-injection acetal resin clasps. Material and Methods: specimens were prepared for clasp retention test injection according to the manufacture's instruction for acetal resin. The first group represent control group with (100% New) and other five groups as experimental groups (group II (25% old +75% new), group III (50% old + 50%) new, and group IV (75% old + 25% new) with different percentages between new acetal materials and old acetal materials, while two last groups with several times (group V (100% old) and group VI (re-injection two times)) only used old acetal materials. The X-ray diffraction (XRD) device used to give structural information for the materials to be tested. The study data were analyzed via One-way ANOVA (LSD) at a significant P-value of (p≤0.05) and a confidence level of 95%. Results: After comparing the results, a significant improvement in the retentive force of acetal clasp specimens after re-injection two times there was found high mean value in group re-injection two times and lower mean value recorded in control group. In XRD patterns of there was no diffraction peak refers to crystal structure of acetal resin. Conclusion: the present study findings concluded that the recycling of acetal resin enhanced the retentive force of acetal clasp and not affected on the crystal structures of material(AU)

Objetivo: Para reduzir os riscos biológicos ambientais, os técnicos devem ser educados com procedimentos seguros de eliminação de resíduos biológicos e reciclagem de material dentário. O presente estudo avalia a força de retenção, teste de deformação e análise de DRX de grampos de resina acetal reinjetada. Material e Métodos: as amostras foram preparadas para o teste de retenção dos grampos e a injeção realizada de acordo com as instruções do fabricante para resina de acetal. O primeiro grupo representa o grupo controle com (100% novo) e os outros cinco grupos como grupos experimentais (grupo II (25% antigo + 75% novo), grupo III (50% antigo + 50% novo) e grupo IV (75% antigo + 25% novo) com porcentagens diferentes entre materiais de acetal novos e antigos, enquanto os dois últimos grupos (grupo V (100% antigo) e grupo VI (reinjeção duas vezes)) utilizaram apenas materiais de acetal antigos. O dispositivo de difração de raios X (DRX) foi utilizado para fornecer informações estruturais dos materiais a testados. Os dados do estudo foram analisados por ANOVA um fator (LSD) com um valor P significativo de (p≤0,05) e um nível de confiança de 95%. Resultados: Após a comparação dos resultados, foi encontrada uma melhora significativa na força de retenção das amostras de grampo de acetal após duas reinjeções, além disso, foi registrado um maior valor médio no grupo reinjeção duas vezes e menor valor médio no grupo controle. Nos padrões de DRX não houve pico de difração referente à estrutura cristalina da resina acetal. Conclusão: os resultados do presente estudo concluíram que a reciclagem da resina de acetal aumentou a força retentiva do grampo e não afetou as estruturas cristalinas do material(AU)

Finite element analyses of retention of removable partial denture circumferential clasps manufactured by selective laser melting / 北京大学学报(医学版)

OBJECTIVE@#To compare the retentions of different designs of cobalt-chromium (Co-Cr), pure titanium (CP Ti), and titanium alloy (Ti-6Al-4V) removable partial denture (RPD) circumferential clasps manufactured by selective laser melting (SLM) and to analyze the stress distribution of these clasps during the removal from abutment teeth.@*METHODS@#Clasps with clasp arm size A (1.9 mm width/1.1 mm thickness at the body and 0.8-taper) or B (1.2 times A) and 0.25 mm or 0.50 mm undercut engagement were modeled on a prepared first premolar die, named as designs A1, A2, A3, and A4, respectively. The density and elastic modulus of SLM-built Co-Cr, CP Ti, and Ti-6Al-4V were measured and given to different groups of clasps. The density, elastic modulus, and Poisson ' s ratio of enamel were given to the die. The control group was the cast Co-Cr clasp with design A1, to which the density and elastic modulus of cast Co-Cr alloy were given. The Poisson's ratio of all metals was 0.33. The initial 5 N dislodging force was applied, and the maximum displacement of the clasp along the insertion path was computed. The load was reapplied with an increment of 5 N than in the last simulation until the clasp was completely dislodged. The retentive force range of different groups of clasps was obtained. The retentive forces of the SLM-built Co-Cr, CP Ti, and Ti-6Al-4V clasps with equivalent computed retentive force range to the control group were validated through the insertion/removal experiment. The von Mises stress distributions of these three groups of SLM-built clasps under 15 N loads were analyzed.@*RESULTS@#SLM-built Co-Cr, CP Ti, and Ti-6Al-4V clasps with designs B1 or B2, and Co-Cr clasps with design A2 had higher retentive forces than those of the control group. SLM-built CP Ti and Ti-6Al-4V clasps with design A1 had lower retentive forces than those of the control group. SLM-built Co-Cr clasp with design A1 and SLM-built CP Ti and Ti-6Al-4V clasps with design A2 had equivalent retentive forces to those of the control group. The insertion/removal experiment showed that the measured retentive forces of these three groups of SLM-built clasps were (21.57±5.41) N, (19.75±4.47) N, and (19.32±2.04) N, respectively. No statistically significant measured retentive force difference was found among these three groups of SLM-built clasps (P>0.05). The maximum von Mises stress of these three groups of SLM-built clasps exceeded their responding yield strength except for the Ti-6Al-4V one.@*CONCLUSION@#SLM-built Co-Cr circumferential clasps had higher retention than CP Ti and Ti-6Al-4V ones with the same clasp arm size and undercut engagement. The retention of SLM-built circumferential clasps could be adjusted by changing the undercut engagement and clasp arm size. If SLM-built circumferential clasps are used in clinical practice, the Ti-6Al-4V clasp with clasp arm size A and 0.50 mm undercut engagement is recommended considering the long-term use of RPD in the patient's mouth.

Physical properties and color stability of injection-molded thermoplastic denture base resins

PURPOSE: The purpose of this study was to compare mechanical and physical properties of injection-molded thermoplastic denture base resins. MATERIALS AND METHODS: In this study, six commercially available products (VA; Valplast, LC; Lucitone, ST; Smiltone, ES; Estheshot-Bright, AC; Acrytone, WE; Weldenz) were selected from four types of thermoplastic denture base materials (Polyamide, Polyester, Acrylic resin and Polypropylene). The flexural properties and shore D hardness have been investigated and water sorption and solubility, and color stability have evaluated. RESULTS: For the flexural modulus value, ES showed the highest value and WE showed significantly lower value than all other groups (P < .05). Most of experimental groups showed weak color stability beyond the clinically acceptable range. CONCLUSION: Within the limits of this study, thermoplastic denture base resin did not show sufficient modulus to function as a denture base. In addition, all resins showed discoloration with clinical significance, and especially polyamides showed the lowest color stability.

Retentiveness comparison of individual clasps made from polyamide, acetate resin and cobalt-chrome for removable partial dentures / Comparação da retenção de grampos individuais de poliamida, resina de acetato e cromo-cobalto para próteses parciais removíveis

Objective: This study aimed to evaluate and compare the retention force of individual clasps made from polyamide, acetate resin and cobalt-chrome for removable partial dentures. Material and methods: Three groups of clasps were fabricated: Cr-Co ­ 10 conventional chrome-cobalt metal clasps; Ac ­ 10 clasps with reciprocal arms and occlusal rests in chrome-cobalt and retentive arms in acetate resin; and Poly - 10 clasps with reciprocal arms and occlusal rests in chrome-cobalt and retentive arms in polyamide resin. Through the tensile test, in a universal testing machine, the initial retention force of the specimens was obtained and then clasps were cycled 7200 times, immersed in artificial saliva (60 months of simulated clinical use). After cycling, tensile test was performed. Results: All groups presented a retention decrease after the cycling. Ac presented a large reduction in retentive force (61.43%), followed by Cr-Co (26.5%) and Poly (12.09%). Conclusions: Aesthetic clasps of polyamide can be used in clinical cases where the anterior supporting teeth will not be essential for good retention of the removable partial denture because this clasp showed to be more resistant than the acetate resin. (AU)

Objetivo: Este estudo teve como objetivo avaliar e comparar a força de retenção de grampos individuais feitos de poliamida, resina de acetato e cromo-cobalto para próteses parciais removíveis. Material e Métodos: Três grupos de grampos foram fabricados: Cr-Co ­ 10 grampos metálicos convencionais de cromo-cobalto; Ac - 10 grampos com apoios e braço de oposição em cromocobalto e braços de retenção em resina de acetato; e Poly - 10 grampos com apoios e braço de oposição em cromo cobalto e braço de retenção em resina de poliamida. Por meio do teste de tração, em uma máquina de ensaio universal, a força de retenção inicial dos espécimes foi obtida e então, os grampos foram ciclados 7200 vezes, imersos em saliva artificial (60 meses de uso clínico simulado). Após a ciclagem, o teste de tração foi realizado. Resultados: Todos os grupos apresentaram diminuição da retenção após a ciclagem. Ac apresentou uma grande redução na força retentiva (61,43%), seguida por Cr-Co (26,5%) e Poly (12,09%). Conclusões: Grampos estéticos de poliamida podem ser usados em casos clínicos em que os dentes de suporte anteriores não serão essenciais para uma boa retenção da prótese parcial removível, pois esse grampo mostrouse mais resistente que os de resina de acetato (AU)

Rehabilitación de maxilares clases I y II de Kennedy mediante prótesis removibles / Rehabilitation of maxillary Kennedy class I & II treated with removable dentures

RESUMEN: La irrupción de los implantes óseo integrados y su posterior validación, a comienzos de los años '80, aportó sin duda un utilísimo recurso en la rehabilitación oral. Lamentablemente, en gran medida debido a los costes económicos involucrados, a pesar de alentadores augurios, no han devenido en una alternativa terapéutica concreta para la gran mayoría de los pacientes desdentados. El edentulismo parcial de maxilas, clases Kennedy I y II, con remanencia de todos o parte de los dientes del sextante 2, en su mayoría casos de sustancial complejidad, léase clases III del Índice Diagnóstico Prostodóntico, genera un desafío protésico a solventar en relación a la retención y satisfacción estética de los pacientes. Presentamos en este reporte dos de estos casos, rehabilitados mediante prótesis metálicas "convencionales", en los cuales creemos logramos conjugar acertadamente ambas variables, combinando complejos retentivos RMC y facetas retentivas friccionales.

ABSTRACT The emergence of osseointegrated implants and their further validation, at the beginning of the 80's, contributed undoubtedly to oral rehabilitation as a very useful resource. Unfortunately, mainly because of the economic costs involved and despite an encouraging initial augury, they have not become in a specific therapeutic alternative for the vast majority of edentulous patients. Partial edentulism of maxillae, Kennedy's class I, & II, with all or a few teeth remaining at the sextant 2, mostly class III PDI, substantially compromised denture-supporting anatomy, generate a prosthetic challenge to overcome regarding retention and aesthetic satisfaction of these patients. In this report, we display two of them, which we believe have been successfully managed in order to fulfill both variables, by means of "conventional" removable metallic prostheses combining MGR's clasps and frictional retentive facets.

The clinical application of modified adams clasp / 实用口腔医学杂志

The disadvantages of Admas clasp include inconvenient manual adjustment and being unsuitable to the deciduous molars.The modified Admas clasp can overcome the shortcomings.

Retentive force comparison between esthetic and metal clasps for removable partial denture / Comparação da força retentiva entre grampos estéticos e metálicos para prótese parcial removível

Objetivo: Este estudo teve como objetivo avaliar a retenção do grampo de resina de acetato quando comparado ao grampo metálico. Material e métodos: Para isso, 10 grampos metálicos Co-Cr convencionais (Ackers) e 20 de resina de acetate foram confeccionados. Os grampos de resina de acetato foram constituídos por braços de oposição, suporte e retenção feitos de CoCr. Dos 20 grampos estéticos, 10 tiveram a espessura do braço de retenção diminuídos para torná-los mais estéticos. A força de retenção inicial dos espécimes foi testada em uma máquina de teste universal através de teste de tração. Depois disso, os espécimes foram submetidos a 7.000 ciclos, cada um, em uma máquina adaptada, imersos em saliva artificial, por 36 meses, simulando uso clínico de uma prótese parcial removível. Os dados foram tabulados para análise estatística da eficácia de retenção. Resultados: Após ciclagem, os grampos de resina de acetato de 3 mm de espessura e 2 mm de espessura perderam mais retenção do que os grampos metálicos. O tipo de material (p = 0,0000) e a ciclagem (p = 0,0039) mostraram um efeito significativo, mas a interação material / ciclagem (p = 0,1436) não. Conclusões: Portanto, os grampos estéticos apresentaram força de retenção inferior à dos grampus metálicos. No entanto, os grampos estéticos podem ser utilizados em casos clínicos que requerem retenção mínima. (AU)

Objective: This study aimed to evaluate the retention of acetate resin clasp as when compared to metal clasp. Material and methods: For this purpose, we constructed 10 conventional Co-Cr metal clasps (Ackers) and 20 acetate resin clasps. The acetate resin clasps had the opposition, support and retaining arms made of Co-Cr. Of the 20 esthetic clasps, 10 had the thickness of the retention arm decreased to make it more esthetic. The initial retentive force of the specimens was tested in a universal testing machine through tensile test. After that, the specimens were subjected to 7,000 cycles, each one, in an adapted machine, immersed into artificial saliva, for 36 months of simulated clinical use of a removable partial denture. Data were tabulated for statistical analysis of the retention effectiveness. Results: After cycling, 3-mm-thick and 2-mmthick acetate resin clasps lost more retention than metal clasps. The material type (p=0.0000) and cycling (p=0.0039) showed a significant effect, but the material/cycling interaction (p=0.1436) did not. Conclusions: Therefore, esthetic clasps presented retention force lower than that of metal clasps. Notwithstanding, the esthetic clasps can be used in clinical cases requiring minimum retention. (AU)

Evaluation And Comparison Of Patient Satisfaction Tendencies And Acceptance For Different Prosthodontic Treatment Modalities.

Objective: To evaluate and compare the denture satisfaction tendencies for and between the completely and partially edentulous patients, with different prosthodontic treatment modalities. Methodology: The study was conducted to include twenty eight patients that were fit to the criteria of the research, asked to answer some questions, reflect their satisfaction with the newly received dentures, which were delivered to patients according to their conditions and needs (complete removable denture, conventional metal frame RPD, RPD with flexible esthetic clasps and RPD with attachments). Results:The data collected from these patients was grouped and the questionnaires values were calculated to estimate the most satisfied group, which was seen with the group who received RPD with flexible esthetic clasps. But the significant difference analysed by Mann-Whitney Test, was focused on the satisfaction of prostheses’ appearance, that was clearly revealed for the patients who received RPD with resilient attachments; followed by the group who received complete dentures and RPD with esthetic flexible clasp (at the same level), supported by the family and friends positive opinions. Also the same group that received RPD with attachments achieved optimum level in prosthesis’ satisfaction for retention. Conclusion:The results of this research directed the attention to the recent treatment modalities in fabrication of dentures, like using flexible esthetic clasps and attachments; the patients that received RPD with flexible esthetic clasps appeared to be more satisfied with their prostheses, mostly this was related to the comfortability, esthetic and retention traits, followed with group that received RPD with attachments that showed significant differences in esthetic and retention scores than other groups. While the complete denture wearers were the less satisfied group, related obviously to the difficulty to gain the retention in relation to the partial once, as well as the uncomfortable feelings.

Definition of Spasticity / The Japanese Journal of Rehabilitation Medicine

<p>Although the term “spasticity” refers to one of the most important concepts in physical medicine and rehabilitation, it is inconsistently defined, particularly in the Japanese literature.<br/>Here, I have presented several definitions widely used throughout Japan and discussed differences among those proposed by Lance, Shimamura, and Tanaka. The use of the phrase “phasic and tonic stretch reflexes” and the meaning of “rigidity” were indicated to cause confusion regarding the definition.<br/>Exaggerated tendon jerks without a reflex response during a continuous muscle stretch should not be included under spasticity. However, if tendon jerks are exaggerated, the increased stretch reflexes without muscle (or joint) movement should be termed “spasticity” rather than “rigidity.” Although some researchers use the term “rigidospasticity” to express severe spasticity, it differs from the original meaning.<br/>According to the discussion, I agree with the definition proposed by Lance：“Spasticity is a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex, as one component of the upper motor neuron syndrome.” However, it is a mysterious phenomenon that depends not only on velocity but also on muscle length. Further review of its definition is required.</p>

Retention force attenuation of 2 kinds of clasps and surface abrasion of the Cr-Co crowns / 实用口腔医学杂志

Objective:To investigate the the retention force changes of 2 kinds of T bar clasps on Cr-Co crowns and the surface ab-rasion of the crowns.Methods:Standard Cr-Co crowns were made,and standard T bar clasps were made of Cr-Co alloy and Vitalli-um2000 with 0.25 mm and 0.5 mm undercut depth respectively.1 800 times repeated placement and removal(fatigue test)were car-ried out on instron testing machine in or without saliva soak condition.The attenuation curves of the maximum retention force was an-alysed.The surface abrasion of the crowns was observed before and after the fatigue test by SEM.Results:The retention force attenu-ation of the clasps in every group was accord with the logarithm attenuation law.SEMexamination showed that in the same condition, there was less surface abrasion in Vitallium2000 group than that in Cr-Co group.Vitallium2000 clasp was superior to Cr-Co clasp in maintaining the retention force.Conclusion:Vitallium2000 T bar clasp may provide better retention force with less furface abrasion on Cr-Co crown than Cr-Co clasp.

Development of Desing of Denture and Treatment Issues / Монголын Анагаах Ухаан

Background An impotant step in maintaining smile to replace missing teeth. When teeth are missing, the remaining ones can change position, drifting the surruonding space. Teeth that are out of position can damage tissues in the mouth. A denture helps you properly chew food, a diffi cult task when you are missing teeth. In addition, a denture may improve speech and prevent sagging face by providing support for lips and cheeks. A partial denture is suitable for those who have some natural teeth remaining.While missing one and two adjacent teeth can often be best restored fi xed bridge or implant, partail denture work best to replace multiple missing teeth. Removable partial denture usually consist of replacement teeth attached to pink or gum- colored plastic bases, which are connected by framework. Removable patial dentures attach to your natural teeth with metal clasp or devices called precision attachment. Precision attachments are generally more estetic and cost more than those metal clasps. Denture with metal and wrought wire clasps are generally more fi t and stay in place much better than (provisional) denture. Objective The main purpose of this study is to develop of provisional denture. Materials and Methods This study has been used to study medicine. Enerel dental clinic served 1481 people whom they were made denture between 2003 and 2005. from those people were made denture with wrought clasp for 60 people. By experimental study, jawing activity test has been used by I.S.Rubinov method. Results Denture with wrought clasp needs was increasing gradually until 56 percents in 2003, 82.1 percents in 2004, 93 percents in 2005. A large number of denture with wrought clasp was made 32.4 percent of maxilla, 47.1 percent was mandible but this denture were used and suited for people 78 percent, 22 percent of people who made those type of denture did not and uncomfortable for them. Denture with wrought clasp jawing activity was 1.920.13 seconds and jawed things weight was1.89 0.1, lost of jawing activity was 2.691.44 (=0.001). Conclusion Method of denture with wrought clasp is simpler and nearly minted removable denture.

Regulation of gastrin and motilin on the tension of human lower esophageal sphincter in vitro / 基础医学与临床

Objective To explore the regulatory mechanism of gastrin and motilin on sling fibers and clasp fibers of human lower esophageal sphincter.Methods Muscle strips of the sling and clasp fibers from human lower esophageal sphincter and the circular layers of the esophagus and gastric fundus were obtained from patients with subtotal esophagectomy.Through the isolated tissue tension detection technique and pharmacological method,the concentration-response curves of the strips responding to gastrin and motilin were constructed,from which E_(max)s were derived.Results All strips contracted to gastrin and motilin with different rules and different intensity in a concentration-dependent fashion.Sling fibers' E_(max)value(4.91?(0.95 mN/mm~(2))) to gastrin was significantly higher than clasp fibers'(0.72?(0.14 mN/mm~(2))).Otherwise,in response to motilin,both sling fibers and clasp fibers contracted to motilin intensively(3.61?(0.65 mN/mm~(2))and 2.64?(0.33 mN/mm~(2))).Conclusions The sling fibers and clasp fibers have different responses to gastrin and motilin.

Stress analysis on the different clasps of the removable partial denture by three-dimensional finite element method / 대한치과보철학회지

STATEMENT OF PROBLEM: In the partially edentulous patients, removable partial dentures have been working as a important treatment modality. Clasps, a kind of direct retainers, received some amount of stresses during the insertion and removal of partial denture on the abutment tooth. PURPOSE: The study is to investigate stresses of the different clasps. MATERIAL AND METHODS: In order to investigate the degree of stresses, maxillary partial edentulism (Kennedy Class II, modification 1) was assumed and removable partial dentures were designed on it with three kinds of metallic materials; cobalt-chromium alloy, type IV gold alloy and commercially pure (c.p.) titanium. Aker's clasp was applied on the left second molar, RPA (mesial rest-proximal plate-Aker's) clasp was on the left first premolar and wrought wire clasp was on the right first premolar. Three dimensional, non-linear, dynamic finite element analysis method was run to solve this process. RESULTS: 1. Cobalt-chromium alloy had the highest von Mises stress value and c.p. titanium had the lowest one irrespective of the types of clasps. 2. In the Aker's clasps, stress on the retentive tips was shown shortly after the appearance of stresses of the middle and minor connector areas. These time lag was much shorter in the RPA clasps than in the Aker's clasp. 3. In general, retentive tips of wrought wire clasps had much less amount of stress than other clasps. CONCLUSION: The amount of stress was the highest in the RPA clasp and the lowest in the wrought wire clasp, in general.

Corrective therapy for different kinds of open bite malformations / 中华医学美学美容杂志

Objective To investigate the effects of a corrective tr ea tment on open bite malformations, such as gnash their teeth, nail-biting, tongu e thrusting, impacted tooth, cross bite with improper correction, open bite defo rmity resulted from premature shedding of deciduous tooth and molar cysts. Methods We used dental resin technology: acid etching the teeth, adh ering metal clasps to the teeth by means of composite resin, and applying elasti c bands for intermaxillary traction to correct the cross bite. Results We had treated 22 patients, age ranged from 7-30, with the malformatio ns resulted from different kinds of reasons, and obtained significant results. Conclusion With cooperation of the patients, simple corrections for open bite with sticky clasp and occlusion with elastic band are easy to car ry on, with short period of treatment time, and every patient gets prominent out come. It is effective, prior to commonly-used corrective therapy and deserves t o be widely used.

A STUDY ON THE STRESS DISTRIBUTION OF ABUTMENT TEETH AND RESIDUAL RIDGE AREA BETWEEN TELESCOPIC AND CLASP TYPE RPD BY FEM METHOD / 대한치과보철학회지

The purpose of this study was to compare and evaluate the stress distribution and displacement developed in the abutment teeth and residual ridge area by madibular unilateral distal extension removable partial denture with 2 different retainer designs. The retainers on right and left canine and right 2nd molar were Akers clasp in one model and telescopic crown in the other model. The stress distribution of abutment teeth and residual ridge area on two model were compared and analyzed with 3-dimensional finite element method. 150N and 400N forces were applied vertically, 30 degree and horizontally on the central fossa area of left 1st molar of the removable partial denture, and then stress distribution patterns were analyzed and compared. The results were as follows 1. As the magnitude and angulation of applied force were increased, the magnitude of stress on the right and central residual ridge area and the right canine of the telescopic type increased and comparing to those of the Akers clasp type. 2. As the magnitude and angulation of applied force were increased, the mesial direction of displacement on the right residual ridge area and the right tooth of the telescopic type increased and the distal direction of displacement on left residual ridge area and the left canine increased comparing to those of Akers clasp type. 3. As the vertical force was applied, the distal direction of the displacement of the right tooth were greater and that of the left canine was smaller and the upward displacement of the right canine was greater in telescopic partial denture than those of Akers clasp type. 4. As the 30 degree force was applied, the mesial direction of the displacement of the right tooth were greater and the distal direction of the displacement of the left canine was smaller and the upward displacement of the right canine was greater in telescopic partial denture than those of Akers clasp type. In the horizontal force the results were same in right area tooth but the distal direction of displacement was greater in left canine. 5. In both removable partial dentures, as the magnitude and degree of force were increased, the stress and displacement were increased. The compressive force was dominative than the tensile force. 6. In both removable partial dentures, the magnitude of stress was greater on mucosal tissue area than that of the alveolar bone area on distal extension residual ridge area but the result was reversed on anterior residual ridge area. The displacement was always greater on mucosal tissue area than that of alveolar bone area.